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1  //===--- SemaDecl.cpp - Semantic Analysis for Declarations ----------------===//
2  //
3  //                     The LLVM Compiler Infrastructure
4  //
5  // This file is distributed under the University of Illinois Open Source
6  // License. See LICENSE.TXT for details.
7  //
8  //===----------------------------------------------------------------------===//
9  //
10  //  This file implements semantic analysis for declarations.
11  //
12  //===----------------------------------------------------------------------===//
13  
14  #include "clang/Sema/SemaInternal.h"
15  #include "TypeLocBuilder.h"
16  #include "clang/AST/ASTConsumer.h"
17  #include "clang/AST/ASTContext.h"
18  #include "clang/AST/ASTLambda.h"
19  #include "clang/AST/CXXInheritance.h"
20  #include "clang/AST/CharUnits.h"
21  #include "clang/AST/CommentDiagnostic.h"
22  #include "clang/AST/DeclCXX.h"
23  #include "clang/AST/DeclObjC.h"
24  #include "clang/AST/DeclTemplate.h"
25  #include "clang/AST/EvaluatedExprVisitor.h"
26  #include "clang/AST/ExprCXX.h"
27  #include "clang/AST/StmtCXX.h"
28  #include "clang/Basic/Builtins.h"
29  #include "clang/Basic/PartialDiagnostic.h"
30  #include "clang/Basic/SourceManager.h"
31  #include "clang/Basic/TargetInfo.h"
32  #include "clang/Lex/HeaderSearch.h" // TODO: Sema shouldn't depend on Lex
33  #include "clang/Lex/Lexer.h" // TODO: Extract static functions to fix layering.
34  #include "clang/Lex/ModuleLoader.h" // TODO: Sema shouldn't depend on Lex
35  #include "clang/Lex/Preprocessor.h" // Included for isCodeCompletionEnabled()
36  #include "clang/Sema/CXXFieldCollector.h"
37  #include "clang/Sema/DeclSpec.h"
38  #include "clang/Sema/DelayedDiagnostic.h"
39  #include "clang/Sema/Initialization.h"
40  #include "clang/Sema/Lookup.h"
41  #include "clang/Sema/ParsedTemplate.h"
42  #include "clang/Sema/Scope.h"
43  #include "clang/Sema/ScopeInfo.h"
44  #include "clang/Sema/Template.h"
45  #include "llvm/ADT/SmallString.h"
46  #include "llvm/ADT/Triple.h"
47  #include <algorithm>
48  #include <cstring>
49  #include <functional>
50  using namespace clang;
51  using namespace sema;
52  
ConvertDeclToDeclGroup(Decl * Ptr,Decl * OwnedType)53  Sema::DeclGroupPtrTy Sema::ConvertDeclToDeclGroup(Decl *Ptr, Decl *OwnedType) {
54    if (OwnedType) {
55      Decl *Group[2] = { OwnedType, Ptr };
56      return DeclGroupPtrTy::make(DeclGroupRef::Create(Context, Group, 2));
57    }
58  
59    return DeclGroupPtrTy::make(DeclGroupRef(Ptr));
60  }
61  
62  namespace {
63  
64  class TypeNameValidatorCCC : public CorrectionCandidateCallback {
65   public:
TypeNameValidatorCCC(bool AllowInvalid,bool WantClass=false,bool AllowTemplates=false)66    TypeNameValidatorCCC(bool AllowInvalid, bool WantClass=false,
67                         bool AllowTemplates=false)
68        : AllowInvalidDecl(AllowInvalid), WantClassName(WantClass),
69          AllowClassTemplates(AllowTemplates) {
70      WantExpressionKeywords = false;
71      WantCXXNamedCasts = false;
72      WantRemainingKeywords = false;
73    }
74  
ValidateCandidate(const TypoCorrection & candidate)75    bool ValidateCandidate(const TypoCorrection &candidate) override {
76      if (NamedDecl *ND = candidate.getCorrectionDecl()) {
77        bool IsType = isa<TypeDecl>(ND) || isa<ObjCInterfaceDecl>(ND);
78        bool AllowedTemplate = AllowClassTemplates && isa<ClassTemplateDecl>(ND);
79        return (IsType || AllowedTemplate) &&
80               (AllowInvalidDecl || !ND->isInvalidDecl());
81      }
82      return !WantClassName && candidate.isKeyword();
83    }
84  
85   private:
86    bool AllowInvalidDecl;
87    bool WantClassName;
88    bool AllowClassTemplates;
89  };
90  
91  }
92  
93  /// \brief Determine whether the token kind starts a simple-type-specifier.
isSimpleTypeSpecifier(tok::TokenKind Kind) const94  bool Sema::isSimpleTypeSpecifier(tok::TokenKind Kind) const {
95    switch (Kind) {
96    // FIXME: Take into account the current language when deciding whether a
97    // token kind is a valid type specifier
98    case tok::kw_short:
99    case tok::kw_long:
100    case tok::kw___int64:
101    case tok::kw___int128:
102    case tok::kw_signed:
103    case tok::kw_unsigned:
104    case tok::kw_void:
105    case tok::kw_char:
106    case tok::kw_int:
107    case tok::kw_half:
108    case tok::kw_float:
109    case tok::kw_double:
110    case tok::kw_wchar_t:
111    case tok::kw_bool:
112    case tok::kw___underlying_type:
113    case tok::kw___auto_type:
114      return true;
115  
116    case tok::annot_typename:
117    case tok::kw_char16_t:
118    case tok::kw_char32_t:
119    case tok::kw_typeof:
120    case tok::annot_decltype:
121    case tok::kw_decltype:
122      return getLangOpts().CPlusPlus;
123  
124    default:
125      break;
126    }
127  
128    return false;
129  }
130  
131  namespace {
132  enum class UnqualifiedTypeNameLookupResult {
133    NotFound,
134    FoundNonType,
135    FoundType
136  };
137  } // namespace
138  
139  /// \brief Tries to perform unqualified lookup of the type decls in bases for
140  /// dependent class.
141  /// \return \a NotFound if no any decls is found, \a FoundNotType if found not a
142  /// type decl, \a FoundType if only type decls are found.
143  static UnqualifiedTypeNameLookupResult
lookupUnqualifiedTypeNameInBase(Sema & S,const IdentifierInfo & II,SourceLocation NameLoc,const CXXRecordDecl * RD)144  lookupUnqualifiedTypeNameInBase(Sema &S, const IdentifierInfo &II,
145                                  SourceLocation NameLoc,
146                                  const CXXRecordDecl *RD) {
147    if (!RD->hasDefinition())
148      return UnqualifiedTypeNameLookupResult::NotFound;
149    // Look for type decls in base classes.
150    UnqualifiedTypeNameLookupResult FoundTypeDecl =
151        UnqualifiedTypeNameLookupResult::NotFound;
152    for (const auto &Base : RD->bases()) {
153      const CXXRecordDecl *BaseRD = nullptr;
154      if (auto *BaseTT = Base.getType()->getAs<TagType>())
155        BaseRD = BaseTT->getAsCXXRecordDecl();
156      else if (auto *TST = Base.getType()->getAs<TemplateSpecializationType>()) {
157        // Look for type decls in dependent base classes that have known primary
158        // templates.
159        if (!TST || !TST->isDependentType())
160          continue;
161        auto *TD = TST->getTemplateName().getAsTemplateDecl();
162        if (!TD)
163          continue;
164        auto *BasePrimaryTemplate =
165            dyn_cast_or_null<CXXRecordDecl>(TD->getTemplatedDecl());
166        if (!BasePrimaryTemplate)
167          continue;
168        BaseRD = BasePrimaryTemplate;
169      }
170      if (BaseRD) {
171        for (NamedDecl *ND : BaseRD->lookup(&II)) {
172          if (!isa<TypeDecl>(ND))
173            return UnqualifiedTypeNameLookupResult::FoundNonType;
174          FoundTypeDecl = UnqualifiedTypeNameLookupResult::FoundType;
175        }
176        if (FoundTypeDecl == UnqualifiedTypeNameLookupResult::NotFound) {
177          switch (lookupUnqualifiedTypeNameInBase(S, II, NameLoc, BaseRD)) {
178          case UnqualifiedTypeNameLookupResult::FoundNonType:
179            return UnqualifiedTypeNameLookupResult::FoundNonType;
180          case UnqualifiedTypeNameLookupResult::FoundType:
181            FoundTypeDecl = UnqualifiedTypeNameLookupResult::FoundType;
182            break;
183          case UnqualifiedTypeNameLookupResult::NotFound:
184            break;
185          }
186        }
187      }
188    }
189  
190    return FoundTypeDecl;
191  }
192  
recoverFromTypeInKnownDependentBase(Sema & S,const IdentifierInfo & II,SourceLocation NameLoc)193  static ParsedType recoverFromTypeInKnownDependentBase(Sema &S,
194                                                        const IdentifierInfo &II,
195                                                        SourceLocation NameLoc) {
196    // Lookup in the parent class template context, if any.
197    const CXXRecordDecl *RD = nullptr;
198    UnqualifiedTypeNameLookupResult FoundTypeDecl =
199        UnqualifiedTypeNameLookupResult::NotFound;
200    for (DeclContext *DC = S.CurContext;
201         DC && FoundTypeDecl == UnqualifiedTypeNameLookupResult::NotFound;
202         DC = DC->getParent()) {
203      // Look for type decls in dependent base classes that have known primary
204      // templates.
205      RD = dyn_cast<CXXRecordDecl>(DC);
206      if (RD && RD->getDescribedClassTemplate())
207        FoundTypeDecl = lookupUnqualifiedTypeNameInBase(S, II, NameLoc, RD);
208    }
209    if (FoundTypeDecl != UnqualifiedTypeNameLookupResult::FoundType)
210      return ParsedType();
211  
212    // We found some types in dependent base classes.  Recover as if the user
213    // wrote 'typename MyClass::II' instead of 'II'.  We'll fully resolve the
214    // lookup during template instantiation.
215    S.Diag(NameLoc, diag::ext_found_via_dependent_bases_lookup) << &II;
216  
217    ASTContext &Context = S.Context;
218    auto *NNS = NestedNameSpecifier::Create(Context, nullptr, false,
219                                            cast<Type>(Context.getRecordType(RD)));
220    QualType T = Context.getDependentNameType(ETK_Typename, NNS, &II);
221  
222    CXXScopeSpec SS;
223    SS.MakeTrivial(Context, NNS, SourceRange(NameLoc));
224  
225    TypeLocBuilder Builder;
226    DependentNameTypeLoc DepTL = Builder.push<DependentNameTypeLoc>(T);
227    DepTL.setNameLoc(NameLoc);
228    DepTL.setElaboratedKeywordLoc(SourceLocation());
229    DepTL.setQualifierLoc(SS.getWithLocInContext(Context));
230    return S.CreateParsedType(T, Builder.getTypeSourceInfo(Context, T));
231  }
232  
233  /// \brief If the identifier refers to a type name within this scope,
234  /// return the declaration of that type.
235  ///
236  /// This routine performs ordinary name lookup of the identifier II
237  /// within the given scope, with optional C++ scope specifier SS, to
238  /// determine whether the name refers to a type. If so, returns an
239  /// opaque pointer (actually a QualType) corresponding to that
240  /// type. Otherwise, returns NULL.
getTypeName(const IdentifierInfo & II,SourceLocation NameLoc,Scope * S,CXXScopeSpec * SS,bool isClassName,bool HasTrailingDot,ParsedType ObjectTypePtr,bool IsCtorOrDtorName,bool WantNontrivialTypeSourceInfo,IdentifierInfo ** CorrectedII)241  ParsedType Sema::getTypeName(const IdentifierInfo &II, SourceLocation NameLoc,
242                               Scope *S, CXXScopeSpec *SS,
243                               bool isClassName, bool HasTrailingDot,
244                               ParsedType ObjectTypePtr,
245                               bool IsCtorOrDtorName,
246                               bool WantNontrivialTypeSourceInfo,
247                               IdentifierInfo **CorrectedII) {
248    // Determine where we will perform name lookup.
249    DeclContext *LookupCtx = nullptr;
250    if (ObjectTypePtr) {
251      QualType ObjectType = ObjectTypePtr.get();
252      if (ObjectType->isRecordType())
253        LookupCtx = computeDeclContext(ObjectType);
254    } else if (SS && SS->isNotEmpty()) {
255      LookupCtx = computeDeclContext(*SS, false);
256  
257      if (!LookupCtx) {
258        if (isDependentScopeSpecifier(*SS)) {
259          // C++ [temp.res]p3:
260          //   A qualified-id that refers to a type and in which the
261          //   nested-name-specifier depends on a template-parameter (14.6.2)
262          //   shall be prefixed by the keyword typename to indicate that the
263          //   qualified-id denotes a type, forming an
264          //   elaborated-type-specifier (7.1.5.3).
265          //
266          // We therefore do not perform any name lookup if the result would
267          // refer to a member of an unknown specialization.
268          if (!isClassName && !IsCtorOrDtorName)
269            return ParsedType();
270  
271          // We know from the grammar that this name refers to a type,
272          // so build a dependent node to describe the type.
273          if (WantNontrivialTypeSourceInfo)
274            return ActOnTypenameType(S, SourceLocation(), *SS, II, NameLoc).get();
275  
276          NestedNameSpecifierLoc QualifierLoc = SS->getWithLocInContext(Context);
277          QualType T = CheckTypenameType(ETK_None, SourceLocation(), QualifierLoc,
278                                         II, NameLoc);
279          return ParsedType::make(T);
280        }
281  
282        return ParsedType();
283      }
284  
285      if (!LookupCtx->isDependentContext() &&
286          RequireCompleteDeclContext(*SS, LookupCtx))
287        return ParsedType();
288    }
289  
290    // FIXME: LookupNestedNameSpecifierName isn't the right kind of
291    // lookup for class-names.
292    LookupNameKind Kind = isClassName ? LookupNestedNameSpecifierName :
293                                        LookupOrdinaryName;
294    LookupResult Result(*this, &II, NameLoc, Kind);
295    if (LookupCtx) {
296      // Perform "qualified" name lookup into the declaration context we
297      // computed, which is either the type of the base of a member access
298      // expression or the declaration context associated with a prior
299      // nested-name-specifier.
300      LookupQualifiedName(Result, LookupCtx);
301  
302      if (ObjectTypePtr && Result.empty()) {
303        // C++ [basic.lookup.classref]p3:
304        //   If the unqualified-id is ~type-name, the type-name is looked up
305        //   in the context of the entire postfix-expression. If the type T of
306        //   the object expression is of a class type C, the type-name is also
307        //   looked up in the scope of class C. At least one of the lookups shall
308        //   find a name that refers to (possibly cv-qualified) T.
309        LookupName(Result, S);
310      }
311    } else {
312      // Perform unqualified name lookup.
313      LookupName(Result, S);
314  
315      // For unqualified lookup in a class template in MSVC mode, look into
316      // dependent base classes where the primary class template is known.
317      if (Result.empty() && getLangOpts().MSVCCompat && (!SS || SS->isEmpty())) {
318        if (ParsedType TypeInBase =
319                recoverFromTypeInKnownDependentBase(*this, II, NameLoc))
320          return TypeInBase;
321      }
322    }
323  
324    NamedDecl *IIDecl = nullptr;
325    switch (Result.getResultKind()) {
326    case LookupResult::NotFound:
327    case LookupResult::NotFoundInCurrentInstantiation:
328      if (CorrectedII) {
329        TypoCorrection Correction = CorrectTypo(
330            Result.getLookupNameInfo(), Kind, S, SS,
331            llvm::make_unique<TypeNameValidatorCCC>(true, isClassName),
332            CTK_ErrorRecovery);
333        IdentifierInfo *NewII = Correction.getCorrectionAsIdentifierInfo();
334        TemplateTy Template;
335        bool MemberOfUnknownSpecialization;
336        UnqualifiedId TemplateName;
337        TemplateName.setIdentifier(NewII, NameLoc);
338        NestedNameSpecifier *NNS = Correction.getCorrectionSpecifier();
339        CXXScopeSpec NewSS, *NewSSPtr = SS;
340        if (SS && NNS) {
341          NewSS.MakeTrivial(Context, NNS, SourceRange(NameLoc));
342          NewSSPtr = &NewSS;
343        }
344        if (Correction && (NNS || NewII != &II) &&
345            // Ignore a correction to a template type as the to-be-corrected
346            // identifier is not a template (typo correction for template names
347            // is handled elsewhere).
348            !(getLangOpts().CPlusPlus && NewSSPtr &&
349              isTemplateName(S, *NewSSPtr, false, TemplateName, ParsedType(),
350                             false, Template, MemberOfUnknownSpecialization))) {
351          ParsedType Ty = getTypeName(*NewII, NameLoc, S, NewSSPtr,
352                                      isClassName, HasTrailingDot, ObjectTypePtr,
353                                      IsCtorOrDtorName,
354                                      WantNontrivialTypeSourceInfo);
355          if (Ty) {
356            diagnoseTypo(Correction,
357                         PDiag(diag::err_unknown_type_or_class_name_suggest)
358                           << Result.getLookupName() << isClassName);
359            if (SS && NNS)
360              SS->MakeTrivial(Context, NNS, SourceRange(NameLoc));
361            *CorrectedII = NewII;
362            return Ty;
363          }
364        }
365      }
366      // If typo correction failed or was not performed, fall through
367    case LookupResult::FoundOverloaded:
368    case LookupResult::FoundUnresolvedValue:
369      Result.suppressDiagnostics();
370      return ParsedType();
371  
372    case LookupResult::Ambiguous:
373      // Recover from type-hiding ambiguities by hiding the type.  We'll
374      // do the lookup again when looking for an object, and we can
375      // diagnose the error then.  If we don't do this, then the error
376      // about hiding the type will be immediately followed by an error
377      // that only makes sense if the identifier was treated like a type.
378      if (Result.getAmbiguityKind() == LookupResult::AmbiguousTagHiding) {
379        Result.suppressDiagnostics();
380        return ParsedType();
381      }
382  
383      // Look to see if we have a type anywhere in the list of results.
384      for (LookupResult::iterator Res = Result.begin(), ResEnd = Result.end();
385           Res != ResEnd; ++Res) {
386        if (isa<TypeDecl>(*Res) || isa<ObjCInterfaceDecl>(*Res)) {
387          if (!IIDecl ||
388              (*Res)->getLocation().getRawEncoding() <
389                IIDecl->getLocation().getRawEncoding())
390            IIDecl = *Res;
391        }
392      }
393  
394      if (!IIDecl) {
395        // None of the entities we found is a type, so there is no way
396        // to even assume that the result is a type. In this case, don't
397        // complain about the ambiguity. The parser will either try to
398        // perform this lookup again (e.g., as an object name), which
399        // will produce the ambiguity, or will complain that it expected
400        // a type name.
401        Result.suppressDiagnostics();
402        return ParsedType();
403      }
404  
405      // We found a type within the ambiguous lookup; diagnose the
406      // ambiguity and then return that type. This might be the right
407      // answer, or it might not be, but it suppresses any attempt to
408      // perform the name lookup again.
409      break;
410  
411    case LookupResult::Found:
412      IIDecl = Result.getFoundDecl();
413      break;
414    }
415  
416    assert(IIDecl && "Didn't find decl");
417  
418    QualType T;
419    if (TypeDecl *TD = dyn_cast<TypeDecl>(IIDecl)) {
420      DiagnoseUseOfDecl(IIDecl, NameLoc);
421  
422      T = Context.getTypeDeclType(TD);
423      MarkAnyDeclReferenced(TD->getLocation(), TD, /*OdrUse=*/false);
424  
425      // NOTE: avoid constructing an ElaboratedType(Loc) if this is a
426      // constructor or destructor name (in such a case, the scope specifier
427      // will be attached to the enclosing Expr or Decl node).
428      if (SS && SS->isNotEmpty() && !IsCtorOrDtorName) {
429        if (WantNontrivialTypeSourceInfo) {
430          // Construct a type with type-source information.
431          TypeLocBuilder Builder;
432          Builder.pushTypeSpec(T).setNameLoc(NameLoc);
433  
434          T = getElaboratedType(ETK_None, *SS, T);
435          ElaboratedTypeLoc ElabTL = Builder.push<ElaboratedTypeLoc>(T);
436          ElabTL.setElaboratedKeywordLoc(SourceLocation());
437          ElabTL.setQualifierLoc(SS->getWithLocInContext(Context));
438          return CreateParsedType(T, Builder.getTypeSourceInfo(Context, T));
439        } else {
440          T = getElaboratedType(ETK_None, *SS, T);
441        }
442      }
443    } else if (ObjCInterfaceDecl *IDecl = dyn_cast<ObjCInterfaceDecl>(IIDecl)) {
444      (void)DiagnoseUseOfDecl(IDecl, NameLoc);
445      if (!HasTrailingDot)
446        T = Context.getObjCInterfaceType(IDecl);
447    }
448  
449    if (T.isNull()) {
450      // If it's not plausibly a type, suppress diagnostics.
451      Result.suppressDiagnostics();
452      return ParsedType();
453    }
454    return ParsedType::make(T);
455  }
456  
457  // Builds a fake NNS for the given decl context.
458  static NestedNameSpecifier *
synthesizeCurrentNestedNameSpecifier(ASTContext & Context,DeclContext * DC)459  synthesizeCurrentNestedNameSpecifier(ASTContext &Context, DeclContext *DC) {
460    for (;; DC = DC->getLookupParent()) {
461      DC = DC->getPrimaryContext();
462      auto *ND = dyn_cast<NamespaceDecl>(DC);
463      if (ND && !ND->isInline() && !ND->isAnonymousNamespace())
464        return NestedNameSpecifier::Create(Context, nullptr, ND);
465      else if (auto *RD = dyn_cast<CXXRecordDecl>(DC))
466        return NestedNameSpecifier::Create(Context, nullptr, RD->isTemplateDecl(),
467                                           RD->getTypeForDecl());
468      else if (isa<TranslationUnitDecl>(DC))
469        return NestedNameSpecifier::GlobalSpecifier(Context);
470    }
471    llvm_unreachable("something isn't in TU scope?");
472  }
473  
ActOnDelayedDefaultTemplateArg(const IdentifierInfo & II,SourceLocation NameLoc)474  ParsedType Sema::ActOnDelayedDefaultTemplateArg(const IdentifierInfo &II,
475                                                  SourceLocation NameLoc) {
476    // Accepting an undeclared identifier as a default argument for a template
477    // type parameter is a Microsoft extension.
478    Diag(NameLoc, diag::ext_ms_delayed_template_argument) << &II;
479  
480    // Build a fake DependentNameType that will perform lookup into CurContext at
481    // instantiation time.  The name specifier isn't dependent, so template
482    // instantiation won't transform it.  It will retry the lookup, however.
483    NestedNameSpecifier *NNS =
484        synthesizeCurrentNestedNameSpecifier(Context, CurContext);
485    QualType T = Context.getDependentNameType(ETK_None, NNS, &II);
486  
487    // Build type location information.  We synthesized the qualifier, so we have
488    // to build a fake NestedNameSpecifierLoc.
489    NestedNameSpecifierLocBuilder NNSLocBuilder;
490    NNSLocBuilder.MakeTrivial(Context, NNS, SourceRange(NameLoc));
491    NestedNameSpecifierLoc QualifierLoc = NNSLocBuilder.getWithLocInContext(Context);
492  
493    TypeLocBuilder Builder;
494    DependentNameTypeLoc DepTL = Builder.push<DependentNameTypeLoc>(T);
495    DepTL.setNameLoc(NameLoc);
496    DepTL.setElaboratedKeywordLoc(SourceLocation());
497    DepTL.setQualifierLoc(QualifierLoc);
498    return CreateParsedType(T, Builder.getTypeSourceInfo(Context, T));
499  }
500  
501  /// isTagName() - This method is called *for error recovery purposes only*
502  /// to determine if the specified name is a valid tag name ("struct foo").  If
503  /// so, this returns the TST for the tag corresponding to it (TST_enum,
504  /// TST_union, TST_struct, TST_interface, TST_class).  This is used to diagnose
505  /// cases in C where the user forgot to specify the tag.
isTagName(IdentifierInfo & II,Scope * S)506  DeclSpec::TST Sema::isTagName(IdentifierInfo &II, Scope *S) {
507    // Do a tag name lookup in this scope.
508    LookupResult R(*this, &II, SourceLocation(), LookupTagName);
509    LookupName(R, S, false);
510    R.suppressDiagnostics();
511    if (R.getResultKind() == LookupResult::Found)
512      if (const TagDecl *TD = R.getAsSingle<TagDecl>()) {
513        switch (TD->getTagKind()) {
514        case TTK_Struct: return DeclSpec::TST_struct;
515        case TTK_Interface: return DeclSpec::TST_interface;
516        case TTK_Union:  return DeclSpec::TST_union;
517        case TTK_Class:  return DeclSpec::TST_class;
518        case TTK_Enum:   return DeclSpec::TST_enum;
519        }
520      }
521  
522    return DeclSpec::TST_unspecified;
523  }
524  
525  /// isMicrosoftMissingTypename - In Microsoft mode, within class scope,
526  /// if a CXXScopeSpec's type is equal to the type of one of the base classes
527  /// then downgrade the missing typename error to a warning.
528  /// This is needed for MSVC compatibility; Example:
529  /// @code
530  /// template<class T> class A {
531  /// public:
532  ///   typedef int TYPE;
533  /// };
534  /// template<class T> class B : public A<T> {
535  /// public:
536  ///   A<T>::TYPE a; // no typename required because A<T> is a base class.
537  /// };
538  /// @endcode
isMicrosoftMissingTypename(const CXXScopeSpec * SS,Scope * S)539  bool Sema::isMicrosoftMissingTypename(const CXXScopeSpec *SS, Scope *S) {
540    if (CurContext->isRecord()) {
541      if (SS->getScopeRep()->getKind() == NestedNameSpecifier::Super)
542        return true;
543  
544      const Type *Ty = SS->getScopeRep()->getAsType();
545  
546      CXXRecordDecl *RD = cast<CXXRecordDecl>(CurContext);
547      for (const auto &Base : RD->bases())
548        if (Context.hasSameUnqualifiedType(QualType(Ty, 1), Base.getType()))
549          return true;
550      return S->isFunctionPrototypeScope();
551    }
552    return CurContext->isFunctionOrMethod() || S->isFunctionPrototypeScope();
553  }
554  
DiagnoseUnknownTypeName(IdentifierInfo * & II,SourceLocation IILoc,Scope * S,CXXScopeSpec * SS,ParsedType & SuggestedType,bool AllowClassTemplates)555  void Sema::DiagnoseUnknownTypeName(IdentifierInfo *&II,
556                                     SourceLocation IILoc,
557                                     Scope *S,
558                                     CXXScopeSpec *SS,
559                                     ParsedType &SuggestedType,
560                                     bool AllowClassTemplates) {
561    // We don't have anything to suggest (yet).
562    SuggestedType = ParsedType();
563  
564    // There may have been a typo in the name of the type. Look up typo
565    // results, in case we have something that we can suggest.
566    if (TypoCorrection Corrected =
567            CorrectTypo(DeclarationNameInfo(II, IILoc), LookupOrdinaryName, S, SS,
568                        llvm::make_unique<TypeNameValidatorCCC>(
569                            false, false, AllowClassTemplates),
570                        CTK_ErrorRecovery)) {
571      if (Corrected.isKeyword()) {
572        // We corrected to a keyword.
573        diagnoseTypo(Corrected, PDiag(diag::err_unknown_typename_suggest) << II);
574        II = Corrected.getCorrectionAsIdentifierInfo();
575      } else {
576        // We found a similarly-named type or interface; suggest that.
577        if (!SS || !SS->isSet()) {
578          diagnoseTypo(Corrected,
579                       PDiag(diag::err_unknown_typename_suggest) << II);
580        } else if (DeclContext *DC = computeDeclContext(*SS, false)) {
581          std::string CorrectedStr(Corrected.getAsString(getLangOpts()));
582          bool DroppedSpecifier = Corrected.WillReplaceSpecifier() &&
583                                  II->getName().equals(CorrectedStr);
584          diagnoseTypo(Corrected,
585                       PDiag(diag::err_unknown_nested_typename_suggest)
586                         << II << DC << DroppedSpecifier << SS->getRange());
587        } else {
588          llvm_unreachable("could not have corrected a typo here");
589        }
590  
591        CXXScopeSpec tmpSS;
592        if (Corrected.getCorrectionSpecifier())
593          tmpSS.MakeTrivial(Context, Corrected.getCorrectionSpecifier(),
594                            SourceRange(IILoc));
595        SuggestedType = getTypeName(*Corrected.getCorrectionAsIdentifierInfo(),
596                                    IILoc, S, tmpSS.isSet() ? &tmpSS : SS, false,
597                                    false, ParsedType(),
598                                    /*IsCtorOrDtorName=*/false,
599                                    /*NonTrivialTypeSourceInfo=*/true);
600      }
601      return;
602    }
603  
604    if (getLangOpts().CPlusPlus) {
605      // See if II is a class template that the user forgot to pass arguments to.
606      UnqualifiedId Name;
607      Name.setIdentifier(II, IILoc);
608      CXXScopeSpec EmptySS;
609      TemplateTy TemplateResult;
610      bool MemberOfUnknownSpecialization;
611      if (isTemplateName(S, SS ? *SS : EmptySS, /*hasTemplateKeyword=*/false,
612                         Name, ParsedType(), true, TemplateResult,
613                         MemberOfUnknownSpecialization) == TNK_Type_template) {
614        TemplateName TplName = TemplateResult.get();
615        Diag(IILoc, diag::err_template_missing_args) << TplName;
616        if (TemplateDecl *TplDecl = TplName.getAsTemplateDecl()) {
617          Diag(TplDecl->getLocation(), diag::note_template_decl_here)
618            << TplDecl->getTemplateParameters()->getSourceRange();
619        }
620        return;
621      }
622    }
623  
624    // FIXME: Should we move the logic that tries to recover from a missing tag
625    // (struct, union, enum) from Parser::ParseImplicitInt here, instead?
626  
627    if (!SS || (!SS->isSet() && !SS->isInvalid()))
628      Diag(IILoc, diag::err_unknown_typename) << II;
629    else if (DeclContext *DC = computeDeclContext(*SS, false))
630      Diag(IILoc, diag::err_typename_nested_not_found)
631        << II << DC << SS->getRange();
632    else if (isDependentScopeSpecifier(*SS)) {
633      unsigned DiagID = diag::err_typename_missing;
634      if (getLangOpts().MSVCCompat && isMicrosoftMissingTypename(SS, S))
635        DiagID = diag::ext_typename_missing;
636  
637      Diag(SS->getRange().getBegin(), DiagID)
638        << SS->getScopeRep() << II->getName()
639        << SourceRange(SS->getRange().getBegin(), IILoc)
640        << FixItHint::CreateInsertion(SS->getRange().getBegin(), "typename ");
641      SuggestedType = ActOnTypenameType(S, SourceLocation(),
642                                        *SS, *II, IILoc).get();
643    } else {
644      assert(SS && SS->isInvalid() &&
645             "Invalid scope specifier has already been diagnosed");
646    }
647  }
648  
649  /// \brief Determine whether the given result set contains either a type name
650  /// or
isResultTypeOrTemplate(LookupResult & R,const Token & NextToken)651  static bool isResultTypeOrTemplate(LookupResult &R, const Token &NextToken) {
652    bool CheckTemplate = R.getSema().getLangOpts().CPlusPlus &&
653                         NextToken.is(tok::less);
654  
655    for (LookupResult::iterator I = R.begin(), IEnd = R.end(); I != IEnd; ++I) {
656      if (isa<TypeDecl>(*I) || isa<ObjCInterfaceDecl>(*I))
657        return true;
658  
659      if (CheckTemplate && isa<TemplateDecl>(*I))
660        return true;
661    }
662  
663    return false;
664  }
665  
isTagTypeWithMissingTag(Sema & SemaRef,LookupResult & Result,Scope * S,CXXScopeSpec & SS,IdentifierInfo * & Name,SourceLocation NameLoc)666  static bool isTagTypeWithMissingTag(Sema &SemaRef, LookupResult &Result,
667                                      Scope *S, CXXScopeSpec &SS,
668                                      IdentifierInfo *&Name,
669                                      SourceLocation NameLoc) {
670    LookupResult R(SemaRef, Name, NameLoc, Sema::LookupTagName);
671    SemaRef.LookupParsedName(R, S, &SS);
672    if (TagDecl *Tag = R.getAsSingle<TagDecl>()) {
673      StringRef FixItTagName;
674      switch (Tag->getTagKind()) {
675        case TTK_Class:
676          FixItTagName = "class ";
677          break;
678  
679        case TTK_Enum:
680          FixItTagName = "enum ";
681          break;
682  
683        case TTK_Struct:
684          FixItTagName = "struct ";
685          break;
686  
687        case TTK_Interface:
688          FixItTagName = "__interface ";
689          break;
690  
691        case TTK_Union:
692          FixItTagName = "union ";
693          break;
694      }
695  
696      StringRef TagName = FixItTagName.drop_back();
697      SemaRef.Diag(NameLoc, diag::err_use_of_tag_name_without_tag)
698        << Name << TagName << SemaRef.getLangOpts().CPlusPlus
699        << FixItHint::CreateInsertion(NameLoc, FixItTagName);
700  
701      for (LookupResult::iterator I = Result.begin(), IEnd = Result.end();
702           I != IEnd; ++I)
703        SemaRef.Diag((*I)->getLocation(), diag::note_decl_hiding_tag_type)
704          << Name << TagName;
705  
706      // Replace lookup results with just the tag decl.
707      Result.clear(Sema::LookupTagName);
708      SemaRef.LookupParsedName(Result, S, &SS);
709      return true;
710    }
711  
712    return false;
713  }
714  
715  /// Build a ParsedType for a simple-type-specifier with a nested-name-specifier.
buildNestedType(Sema & S,CXXScopeSpec & SS,QualType T,SourceLocation NameLoc)716  static ParsedType buildNestedType(Sema &S, CXXScopeSpec &SS,
717                                    QualType T, SourceLocation NameLoc) {
718    ASTContext &Context = S.Context;
719  
720    TypeLocBuilder Builder;
721    Builder.pushTypeSpec(T).setNameLoc(NameLoc);
722  
723    T = S.getElaboratedType(ETK_None, SS, T);
724    ElaboratedTypeLoc ElabTL = Builder.push<ElaboratedTypeLoc>(T);
725    ElabTL.setElaboratedKeywordLoc(SourceLocation());
726    ElabTL.setQualifierLoc(SS.getWithLocInContext(Context));
727    return S.CreateParsedType(T, Builder.getTypeSourceInfo(Context, T));
728  }
729  
730  Sema::NameClassification
ClassifyName(Scope * S,CXXScopeSpec & SS,IdentifierInfo * & Name,SourceLocation NameLoc,const Token & NextToken,bool IsAddressOfOperand,std::unique_ptr<CorrectionCandidateCallback> CCC)731  Sema::ClassifyName(Scope *S, CXXScopeSpec &SS, IdentifierInfo *&Name,
732                     SourceLocation NameLoc, const Token &NextToken,
733                     bool IsAddressOfOperand,
734                     std::unique_ptr<CorrectionCandidateCallback> CCC) {
735    DeclarationNameInfo NameInfo(Name, NameLoc);
736    ObjCMethodDecl *CurMethod = getCurMethodDecl();
737  
738    if (NextToken.is(tok::coloncolon)) {
739      BuildCXXNestedNameSpecifier(S, *Name, NameLoc, NextToken.getLocation(),
740                                  QualType(), false, SS, nullptr, false);
741    }
742  
743    LookupResult Result(*this, Name, NameLoc, LookupOrdinaryName);
744    LookupParsedName(Result, S, &SS, !CurMethod);
745  
746    // For unqualified lookup in a class template in MSVC mode, look into
747    // dependent base classes where the primary class template is known.
748    if (Result.empty() && SS.isEmpty() && getLangOpts().MSVCCompat) {
749      if (ParsedType TypeInBase =
750              recoverFromTypeInKnownDependentBase(*this, *Name, NameLoc))
751        return TypeInBase;
752    }
753  
754    // Perform lookup for Objective-C instance variables (including automatically
755    // synthesized instance variables), if we're in an Objective-C method.
756    // FIXME: This lookup really, really needs to be folded in to the normal
757    // unqualified lookup mechanism.
758    if (!SS.isSet() && CurMethod && !isResultTypeOrTemplate(Result, NextToken)) {
759      ExprResult E = LookupInObjCMethod(Result, S, Name, true);
760      if (E.get() || E.isInvalid())
761        return E;
762    }
763  
764    bool SecondTry = false;
765    bool IsFilteredTemplateName = false;
766  
767  Corrected:
768    switch (Result.getResultKind()) {
769    case LookupResult::NotFound:
770      // If an unqualified-id is followed by a '(', then we have a function
771      // call.
772      if (!SS.isSet() && NextToken.is(tok::l_paren)) {
773        // In C++, this is an ADL-only call.
774        // FIXME: Reference?
775        if (getLangOpts().CPlusPlus)
776          return BuildDeclarationNameExpr(SS, Result, /*ADL=*/true);
777  
778        // C90 6.3.2.2:
779        //   If the expression that precedes the parenthesized argument list in a
780        //   function call consists solely of an identifier, and if no
781        //   declaration is visible for this identifier, the identifier is
782        //   implicitly declared exactly as if, in the innermost block containing
783        //   the function call, the declaration
784        //
785        //     extern int identifier ();
786        //
787        //   appeared.
788        //
789        // We also allow this in C99 as an extension.
790        if (NamedDecl *D = ImplicitlyDefineFunction(NameLoc, *Name, S)) {
791          Result.addDecl(D);
792          Result.resolveKind();
793          return BuildDeclarationNameExpr(SS, Result, /*ADL=*/false);
794        }
795      }
796  
797      // In C, we first see whether there is a tag type by the same name, in
798      // which case it's likely that the user just forget to write "enum",
799      // "struct", or "union".
800      if (!getLangOpts().CPlusPlus && !SecondTry &&
801          isTagTypeWithMissingTag(*this, Result, S, SS, Name, NameLoc)) {
802        break;
803      }
804  
805      // Perform typo correction to determine if there is another name that is
806      // close to this name.
807      if (!SecondTry && CCC) {
808        SecondTry = true;
809        if (TypoCorrection Corrected = CorrectTypo(Result.getLookupNameInfo(),
810                                                   Result.getLookupKind(), S,
811                                                   &SS, std::move(CCC),
812                                                   CTK_ErrorRecovery)) {
813          unsigned UnqualifiedDiag = diag::err_undeclared_var_use_suggest;
814          unsigned QualifiedDiag = diag::err_no_member_suggest;
815  
816          NamedDecl *FirstDecl = Corrected.getCorrectionDecl();
817          NamedDecl *UnderlyingFirstDecl
818            = FirstDecl? FirstDecl->getUnderlyingDecl() : nullptr;
819          if (getLangOpts().CPlusPlus && NextToken.is(tok::less) &&
820              UnderlyingFirstDecl && isa<TemplateDecl>(UnderlyingFirstDecl)) {
821            UnqualifiedDiag = diag::err_no_template_suggest;
822            QualifiedDiag = diag::err_no_member_template_suggest;
823          } else if (UnderlyingFirstDecl &&
824                     (isa<TypeDecl>(UnderlyingFirstDecl) ||
825                      isa<ObjCInterfaceDecl>(UnderlyingFirstDecl) ||
826                      isa<ObjCCompatibleAliasDecl>(UnderlyingFirstDecl))) {
827            UnqualifiedDiag = diag::err_unknown_typename_suggest;
828            QualifiedDiag = diag::err_unknown_nested_typename_suggest;
829          }
830  
831          if (SS.isEmpty()) {
832            diagnoseTypo(Corrected, PDiag(UnqualifiedDiag) << Name);
833          } else {// FIXME: is this even reachable? Test it.
834            std::string CorrectedStr(Corrected.getAsString(getLangOpts()));
835            bool DroppedSpecifier = Corrected.WillReplaceSpecifier() &&
836                                    Name->getName().equals(CorrectedStr);
837            diagnoseTypo(Corrected, PDiag(QualifiedDiag)
838                                      << Name << computeDeclContext(SS, false)
839                                      << DroppedSpecifier << SS.getRange());
840          }
841  
842          // Update the name, so that the caller has the new name.
843          Name = Corrected.getCorrectionAsIdentifierInfo();
844  
845          // Typo correction corrected to a keyword.
846          if (Corrected.isKeyword())
847            return Name;
848  
849          // Also update the LookupResult...
850          // FIXME: This should probably go away at some point
851          Result.clear();
852          Result.setLookupName(Corrected.getCorrection());
853          if (FirstDecl)
854            Result.addDecl(FirstDecl);
855  
856          // If we found an Objective-C instance variable, let
857          // LookupInObjCMethod build the appropriate expression to
858          // reference the ivar.
859          // FIXME: This is a gross hack.
860          if (ObjCIvarDecl *Ivar = Result.getAsSingle<ObjCIvarDecl>()) {
861            Result.clear();
862            ExprResult E(LookupInObjCMethod(Result, S, Ivar->getIdentifier()));
863            return E;
864          }
865  
866          goto Corrected;
867        }
868      }
869  
870      // We failed to correct; just fall through and let the parser deal with it.
871      Result.suppressDiagnostics();
872      return NameClassification::Unknown();
873  
874    case LookupResult::NotFoundInCurrentInstantiation: {
875      // We performed name lookup into the current instantiation, and there were
876      // dependent bases, so we treat this result the same way as any other
877      // dependent nested-name-specifier.
878  
879      // C++ [temp.res]p2:
880      //   A name used in a template declaration or definition and that is
881      //   dependent on a template-parameter is assumed not to name a type
882      //   unless the applicable name lookup finds a type name or the name is
883      //   qualified by the keyword typename.
884      //
885      // FIXME: If the next token is '<', we might want to ask the parser to
886      // perform some heroics to see if we actually have a
887      // template-argument-list, which would indicate a missing 'template'
888      // keyword here.
889      return ActOnDependentIdExpression(SS, /*TemplateKWLoc=*/SourceLocation(),
890                                        NameInfo, IsAddressOfOperand,
891                                        /*TemplateArgs=*/nullptr);
892    }
893  
894    case LookupResult::Found:
895    case LookupResult::FoundOverloaded:
896    case LookupResult::FoundUnresolvedValue:
897      break;
898  
899    case LookupResult::Ambiguous:
900      if (getLangOpts().CPlusPlus && NextToken.is(tok::less) &&
901          hasAnyAcceptableTemplateNames(Result)) {
902        // C++ [temp.local]p3:
903        //   A lookup that finds an injected-class-name (10.2) can result in an
904        //   ambiguity in certain cases (for example, if it is found in more than
905        //   one base class). If all of the injected-class-names that are found
906        //   refer to specializations of the same class template, and if the name
907        //   is followed by a template-argument-list, the reference refers to the
908        //   class template itself and not a specialization thereof, and is not
909        //   ambiguous.
910        //
911        // This filtering can make an ambiguous result into an unambiguous one,
912        // so try again after filtering out template names.
913        FilterAcceptableTemplateNames(Result);
914        if (!Result.isAmbiguous()) {
915          IsFilteredTemplateName = true;
916          break;
917        }
918      }
919  
920      // Diagnose the ambiguity and return an error.
921      return NameClassification::Error();
922    }
923  
924    if (getLangOpts().CPlusPlus && NextToken.is(tok::less) &&
925        (IsFilteredTemplateName || hasAnyAcceptableTemplateNames(Result))) {
926      // C++ [temp.names]p3:
927      //   After name lookup (3.4) finds that a name is a template-name or that
928      //   an operator-function-id or a literal- operator-id refers to a set of
929      //   overloaded functions any member of which is a function template if
930      //   this is followed by a <, the < is always taken as the delimiter of a
931      //   template-argument-list and never as the less-than operator.
932      if (!IsFilteredTemplateName)
933        FilterAcceptableTemplateNames(Result);
934  
935      if (!Result.empty()) {
936        bool IsFunctionTemplate;
937        bool IsVarTemplate;
938        TemplateName Template;
939        if (Result.end() - Result.begin() > 1) {
940          IsFunctionTemplate = true;
941          Template = Context.getOverloadedTemplateName(Result.begin(),
942                                                       Result.end());
943        } else {
944          TemplateDecl *TD
945            = cast<TemplateDecl>((*Result.begin())->getUnderlyingDecl());
946          IsFunctionTemplate = isa<FunctionTemplateDecl>(TD);
947          IsVarTemplate = isa<VarTemplateDecl>(TD);
948  
949          if (SS.isSet() && !SS.isInvalid())
950            Template = Context.getQualifiedTemplateName(SS.getScopeRep(),
951                                                      /*TemplateKeyword=*/false,
952                                                        TD);
953          else
954            Template = TemplateName(TD);
955        }
956  
957        if (IsFunctionTemplate) {
958          // Function templates always go through overload resolution, at which
959          // point we'll perform the various checks (e.g., accessibility) we need
960          // to based on which function we selected.
961          Result.suppressDiagnostics();
962  
963          return NameClassification::FunctionTemplate(Template);
964        }
965  
966        return IsVarTemplate ? NameClassification::VarTemplate(Template)
967                             : NameClassification::TypeTemplate(Template);
968      }
969    }
970  
971    NamedDecl *FirstDecl = (*Result.begin())->getUnderlyingDecl();
972    if (TypeDecl *Type = dyn_cast<TypeDecl>(FirstDecl)) {
973      DiagnoseUseOfDecl(Type, NameLoc);
974      MarkAnyDeclReferenced(Type->getLocation(), Type, /*OdrUse=*/false);
975      QualType T = Context.getTypeDeclType(Type);
976      if (SS.isNotEmpty())
977        return buildNestedType(*this, SS, T, NameLoc);
978      return ParsedType::make(T);
979    }
980  
981    ObjCInterfaceDecl *Class = dyn_cast<ObjCInterfaceDecl>(FirstDecl);
982    if (!Class) {
983      // FIXME: It's unfortunate that we don't have a Type node for handling this.
984      if (ObjCCompatibleAliasDecl *Alias =
985              dyn_cast<ObjCCompatibleAliasDecl>(FirstDecl))
986        Class = Alias->getClassInterface();
987    }
988  
989    if (Class) {
990      DiagnoseUseOfDecl(Class, NameLoc);
991  
992      if (NextToken.is(tok::period)) {
993        // Interface. <something> is parsed as a property reference expression.
994        // Just return "unknown" as a fall-through for now.
995        Result.suppressDiagnostics();
996        return NameClassification::Unknown();
997      }
998  
999      QualType T = Context.getObjCInterfaceType(Class);
1000      return ParsedType::make(T);
1001    }
1002  
1003    // We can have a type template here if we're classifying a template argument.
1004    if (isa<TemplateDecl>(FirstDecl) && !isa<FunctionTemplateDecl>(FirstDecl))
1005      return NameClassification::TypeTemplate(
1006          TemplateName(cast<TemplateDecl>(FirstDecl)));
1007  
1008    // Check for a tag type hidden by a non-type decl in a few cases where it
1009    // seems likely a type is wanted instead of the non-type that was found.
1010    bool NextIsOp = NextToken.isOneOf(tok::amp, tok::star);
1011    if ((NextToken.is(tok::identifier) ||
1012         (NextIsOp &&
1013          FirstDecl->getUnderlyingDecl()->isFunctionOrFunctionTemplate())) &&
1014        isTagTypeWithMissingTag(*this, Result, S, SS, Name, NameLoc)) {
1015      TypeDecl *Type = Result.getAsSingle<TypeDecl>();
1016      DiagnoseUseOfDecl(Type, NameLoc);
1017      QualType T = Context.getTypeDeclType(Type);
1018      if (SS.isNotEmpty())
1019        return buildNestedType(*this, SS, T, NameLoc);
1020      return ParsedType::make(T);
1021    }
1022  
1023    if (FirstDecl->isCXXClassMember())
1024      return BuildPossibleImplicitMemberExpr(SS, SourceLocation(), Result,
1025                                             nullptr, S);
1026  
1027    bool ADL = UseArgumentDependentLookup(SS, Result, NextToken.is(tok::l_paren));
1028    return BuildDeclarationNameExpr(SS, Result, ADL);
1029  }
1030  
1031  // Determines the context to return to after temporarily entering a
1032  // context.  This depends in an unnecessarily complicated way on the
1033  // exact ordering of callbacks from the parser.
getContainingDC(DeclContext * DC)1034  DeclContext *Sema::getContainingDC(DeclContext *DC) {
1035  
1036    // Functions defined inline within classes aren't parsed until we've
1037    // finished parsing the top-level class, so the top-level class is
1038    // the context we'll need to return to.
1039    // A Lambda call operator whose parent is a class must not be treated
1040    // as an inline member function.  A Lambda can be used legally
1041    // either as an in-class member initializer or a default argument.  These
1042    // are parsed once the class has been marked complete and so the containing
1043    // context would be the nested class (when the lambda is defined in one);
1044    // If the class is not complete, then the lambda is being used in an
1045    // ill-formed fashion (such as to specify the width of a bit-field, or
1046    // in an array-bound) - in which case we still want to return the
1047    // lexically containing DC (which could be a nested class).
1048    if (isa<FunctionDecl>(DC) && !isLambdaCallOperator(DC)) {
1049      DC = DC->getLexicalParent();
1050  
1051      // A function not defined within a class will always return to its
1052      // lexical context.
1053      if (!isa<CXXRecordDecl>(DC))
1054        return DC;
1055  
1056      // A C++ inline method/friend is parsed *after* the topmost class
1057      // it was declared in is fully parsed ("complete");  the topmost
1058      // class is the context we need to return to.
1059      while (CXXRecordDecl *RD = dyn_cast<CXXRecordDecl>(DC->getLexicalParent()))
1060        DC = RD;
1061  
1062      // Return the declaration context of the topmost class the inline method is
1063      // declared in.
1064      return DC;
1065    }
1066  
1067    return DC->getLexicalParent();
1068  }
1069  
PushDeclContext(Scope * S,DeclContext * DC)1070  void Sema::PushDeclContext(Scope *S, DeclContext *DC) {
1071    assert(getContainingDC(DC) == CurContext &&
1072        "The next DeclContext should be lexically contained in the current one.");
1073    CurContext = DC;
1074    S->setEntity(DC);
1075  }
1076  
PopDeclContext()1077  void Sema::PopDeclContext() {
1078    assert(CurContext && "DeclContext imbalance!");
1079  
1080    CurContext = getContainingDC(CurContext);
1081    assert(CurContext && "Popped translation unit!");
1082  }
1083  
ActOnTagStartSkippedDefinition(Scope * S,Decl * D)1084  Sema::SkippedDefinitionContext Sema::ActOnTagStartSkippedDefinition(Scope *S,
1085                                                                      Decl *D) {
1086    // Unlike PushDeclContext, the context to which we return is not necessarily
1087    // the containing DC of TD, because the new context will be some pre-existing
1088    // TagDecl definition instead of a fresh one.
1089    auto Result = static_cast<SkippedDefinitionContext>(CurContext);
1090    CurContext = cast<TagDecl>(D)->getDefinition();
1091    assert(CurContext && "skipping definition of undefined tag");
1092    // Start lookups from the parent of the current context; we don't want to look
1093    // into the pre-existing complete definition.
1094    S->setEntity(CurContext->getLookupParent());
1095    return Result;
1096  }
1097  
ActOnTagFinishSkippedDefinition(SkippedDefinitionContext Context)1098  void Sema::ActOnTagFinishSkippedDefinition(SkippedDefinitionContext Context) {
1099    CurContext = static_cast<decltype(CurContext)>(Context);
1100  }
1101  
1102  /// EnterDeclaratorContext - Used when we must lookup names in the context
1103  /// of a declarator's nested name specifier.
1104  ///
EnterDeclaratorContext(Scope * S,DeclContext * DC)1105  void Sema::EnterDeclaratorContext(Scope *S, DeclContext *DC) {
1106    // C++0x [basic.lookup.unqual]p13:
1107    //   A name used in the definition of a static data member of class
1108    //   X (after the qualified-id of the static member) is looked up as
1109    //   if the name was used in a member function of X.
1110    // C++0x [basic.lookup.unqual]p14:
1111    //   If a variable member of a namespace is defined outside of the
1112    //   scope of its namespace then any name used in the definition of
1113    //   the variable member (after the declarator-id) is looked up as
1114    //   if the definition of the variable member occurred in its
1115    //   namespace.
1116    // Both of these imply that we should push a scope whose context
1117    // is the semantic context of the declaration.  We can't use
1118    // PushDeclContext here because that context is not necessarily
1119    // lexically contained in the current context.  Fortunately,
1120    // the containing scope should have the appropriate information.
1121  
1122    assert(!S->getEntity() && "scope already has entity");
1123  
1124  #ifndef NDEBUG
1125    Scope *Ancestor = S->getParent();
1126    while (!Ancestor->getEntity()) Ancestor = Ancestor->getParent();
1127    assert(Ancestor->getEntity() == CurContext && "ancestor context mismatch");
1128  #endif
1129  
1130    CurContext = DC;
1131    S->setEntity(DC);
1132  }
1133  
ExitDeclaratorContext(Scope * S)1134  void Sema::ExitDeclaratorContext(Scope *S) {
1135    assert(S->getEntity() == CurContext && "Context imbalance!");
1136  
1137    // Switch back to the lexical context.  The safety of this is
1138    // enforced by an assert in EnterDeclaratorContext.
1139    Scope *Ancestor = S->getParent();
1140    while (!Ancestor->getEntity()) Ancestor = Ancestor->getParent();
1141    CurContext = Ancestor->getEntity();
1142  
1143    // We don't need to do anything with the scope, which is going to
1144    // disappear.
1145  }
1146  
1147  
ActOnReenterFunctionContext(Scope * S,Decl * D)1148  void Sema::ActOnReenterFunctionContext(Scope* S, Decl *D) {
1149    // We assume that the caller has already called
1150    // ActOnReenterTemplateScope so getTemplatedDecl() works.
1151    FunctionDecl *FD = D->getAsFunction();
1152    if (!FD)
1153      return;
1154  
1155    // Same implementation as PushDeclContext, but enters the context
1156    // from the lexical parent, rather than the top-level class.
1157    assert(CurContext == FD->getLexicalParent() &&
1158      "The next DeclContext should be lexically contained in the current one.");
1159    CurContext = FD;
1160    S->setEntity(CurContext);
1161  
1162    for (unsigned P = 0, NumParams = FD->getNumParams(); P < NumParams; ++P) {
1163      ParmVarDecl *Param = FD->getParamDecl(P);
1164      // If the parameter has an identifier, then add it to the scope
1165      if (Param->getIdentifier()) {
1166        S->AddDecl(Param);
1167        IdResolver.AddDecl(Param);
1168      }
1169    }
1170  }
1171  
1172  
ActOnExitFunctionContext()1173  void Sema::ActOnExitFunctionContext() {
1174    // Same implementation as PopDeclContext, but returns to the lexical parent,
1175    // rather than the top-level class.
1176    assert(CurContext && "DeclContext imbalance!");
1177    CurContext = CurContext->getLexicalParent();
1178    assert(CurContext && "Popped translation unit!");
1179  }
1180  
1181  
1182  /// \brief Determine whether we allow overloading of the function
1183  /// PrevDecl with another declaration.
1184  ///
1185  /// This routine determines whether overloading is possible, not
1186  /// whether some new function is actually an overload. It will return
1187  /// true in C++ (where we can always provide overloads) or, as an
1188  /// extension, in C when the previous function is already an
1189  /// overloaded function declaration or has the "overloadable"
1190  /// attribute.
AllowOverloadingOfFunction(LookupResult & Previous,ASTContext & Context)1191  static bool AllowOverloadingOfFunction(LookupResult &Previous,
1192                                         ASTContext &Context) {
1193    if (Context.getLangOpts().CPlusPlus)
1194      return true;
1195  
1196    if (Previous.getResultKind() == LookupResult::FoundOverloaded)
1197      return true;
1198  
1199    return (Previous.getResultKind() == LookupResult::Found
1200            && Previous.getFoundDecl()->hasAttr<OverloadableAttr>());
1201  }
1202  
1203  /// Add this decl to the scope shadowed decl chains.
PushOnScopeChains(NamedDecl * D,Scope * S,bool AddToContext)1204  void Sema::PushOnScopeChains(NamedDecl *D, Scope *S, bool AddToContext) {
1205    // Move up the scope chain until we find the nearest enclosing
1206    // non-transparent context. The declaration will be introduced into this
1207    // scope.
1208    while (S->getEntity() && S->getEntity()->isTransparentContext())
1209      S = S->getParent();
1210  
1211    // Add scoped declarations into their context, so that they can be
1212    // found later. Declarations without a context won't be inserted
1213    // into any context.
1214    if (AddToContext)
1215      CurContext->addDecl(D);
1216  
1217    // Out-of-line definitions shouldn't be pushed into scope in C++, unless they
1218    // are function-local declarations.
1219    if (getLangOpts().CPlusPlus && D->isOutOfLine() &&
1220        !D->getDeclContext()->getRedeclContext()->Equals(
1221          D->getLexicalDeclContext()->getRedeclContext()) &&
1222        !D->getLexicalDeclContext()->isFunctionOrMethod())
1223      return;
1224  
1225    // Template instantiations should also not be pushed into scope.
1226    if (isa<FunctionDecl>(D) &&
1227        cast<FunctionDecl>(D)->isFunctionTemplateSpecialization())
1228      return;
1229  
1230    // If this replaces anything in the current scope,
1231    IdentifierResolver::iterator I = IdResolver.begin(D->getDeclName()),
1232                                 IEnd = IdResolver.end();
1233    for (; I != IEnd; ++I) {
1234      if (S->isDeclScope(*I) && D->declarationReplaces(*I)) {
1235        S->RemoveDecl(*I);
1236        IdResolver.RemoveDecl(*I);
1237  
1238        // Should only need to replace one decl.
1239        break;
1240      }
1241    }
1242  
1243    S->AddDecl(D);
1244  
1245    if (isa<LabelDecl>(D) && !cast<LabelDecl>(D)->isGnuLocal()) {
1246      // Implicitly-generated labels may end up getting generated in an order that
1247      // isn't strictly lexical, which breaks name lookup. Be careful to insert
1248      // the label at the appropriate place in the identifier chain.
1249      for (I = IdResolver.begin(D->getDeclName()); I != IEnd; ++I) {
1250        DeclContext *IDC = (*I)->getLexicalDeclContext()->getRedeclContext();
1251        if (IDC == CurContext) {
1252          if (!S->isDeclScope(*I))
1253            continue;
1254        } else if (IDC->Encloses(CurContext))
1255          break;
1256      }
1257  
1258      IdResolver.InsertDeclAfter(I, D);
1259    } else {
1260      IdResolver.AddDecl(D);
1261    }
1262  }
1263  
pushExternalDeclIntoScope(NamedDecl * D,DeclarationName Name)1264  void Sema::pushExternalDeclIntoScope(NamedDecl *D, DeclarationName Name) {
1265    if (IdResolver.tryAddTopLevelDecl(D, Name) && TUScope)
1266      TUScope->AddDecl(D);
1267  }
1268  
isDeclInScope(NamedDecl * D,DeclContext * Ctx,Scope * S,bool AllowInlineNamespace)1269  bool Sema::isDeclInScope(NamedDecl *D, DeclContext *Ctx, Scope *S,
1270                           bool AllowInlineNamespace) {
1271    return IdResolver.isDeclInScope(D, Ctx, S, AllowInlineNamespace);
1272  }
1273  
getScopeForDeclContext(Scope * S,DeclContext * DC)1274  Scope *Sema::getScopeForDeclContext(Scope *S, DeclContext *DC) {
1275    DeclContext *TargetDC = DC->getPrimaryContext();
1276    do {
1277      if (DeclContext *ScopeDC = S->getEntity())
1278        if (ScopeDC->getPrimaryContext() == TargetDC)
1279          return S;
1280    } while ((S = S->getParent()));
1281  
1282    return nullptr;
1283  }
1284  
1285  static bool isOutOfScopePreviousDeclaration(NamedDecl *,
1286                                              DeclContext*,
1287                                              ASTContext&);
1288  
1289  /// Filters out lookup results that don't fall within the given scope
1290  /// as determined by isDeclInScope.
FilterLookupForScope(LookupResult & R,DeclContext * Ctx,Scope * S,bool ConsiderLinkage,bool AllowInlineNamespace)1291  void Sema::FilterLookupForScope(LookupResult &R, DeclContext *Ctx, Scope *S,
1292                                  bool ConsiderLinkage,
1293                                  bool AllowInlineNamespace) {
1294    LookupResult::Filter F = R.makeFilter();
1295    while (F.hasNext()) {
1296      NamedDecl *D = F.next();
1297  
1298      if (isDeclInScope(D, Ctx, S, AllowInlineNamespace))
1299        continue;
1300  
1301      if (ConsiderLinkage && isOutOfScopePreviousDeclaration(D, Ctx, Context))
1302        continue;
1303  
1304      F.erase();
1305    }
1306  
1307    F.done();
1308  }
1309  
isUsingDecl(NamedDecl * D)1310  static bool isUsingDecl(NamedDecl *D) {
1311    return isa<UsingShadowDecl>(D) ||
1312           isa<UnresolvedUsingTypenameDecl>(D) ||
1313           isa<UnresolvedUsingValueDecl>(D);
1314  }
1315  
1316  /// Removes using shadow declarations from the lookup results.
RemoveUsingDecls(LookupResult & R)1317  static void RemoveUsingDecls(LookupResult &R) {
1318    LookupResult::Filter F = R.makeFilter();
1319    while (F.hasNext())
1320      if (isUsingDecl(F.next()))
1321        F.erase();
1322  
1323    F.done();
1324  }
1325  
1326  /// \brief Check for this common pattern:
1327  /// @code
1328  /// class S {
1329  ///   S(const S&); // DO NOT IMPLEMENT
1330  ///   void operator=(const S&); // DO NOT IMPLEMENT
1331  /// };
1332  /// @endcode
IsDisallowedCopyOrAssign(const CXXMethodDecl * D)1333  static bool IsDisallowedCopyOrAssign(const CXXMethodDecl *D) {
1334    // FIXME: Should check for private access too but access is set after we get
1335    // the decl here.
1336    if (D->doesThisDeclarationHaveABody())
1337      return false;
1338  
1339    if (const CXXConstructorDecl *CD = dyn_cast<CXXConstructorDecl>(D))
1340      return CD->isCopyConstructor();
1341    if (const CXXMethodDecl *Method = dyn_cast<CXXMethodDecl>(D))
1342      return Method->isCopyAssignmentOperator();
1343    return false;
1344  }
1345  
1346  // We need this to handle
1347  //
1348  // typedef struct {
1349  //   void *foo() { return 0; }
1350  // } A;
1351  //
1352  // When we see foo we don't know if after the typedef we will get 'A' or '*A'
1353  // for example. If 'A', foo will have external linkage. If we have '*A',
1354  // foo will have no linkage. Since we can't know until we get to the end
1355  // of the typedef, this function finds out if D might have non-external linkage.
1356  // Callers should verify at the end of the TU if it D has external linkage or
1357  // not.
mightHaveNonExternalLinkage(const DeclaratorDecl * D)1358  bool Sema::mightHaveNonExternalLinkage(const DeclaratorDecl *D) {
1359    const DeclContext *DC = D->getDeclContext();
1360    while (!DC->isTranslationUnit()) {
1361      if (const RecordDecl *RD = dyn_cast<RecordDecl>(DC)){
1362        if (!RD->hasNameForLinkage())
1363          return true;
1364      }
1365      DC = DC->getParent();
1366    }
1367  
1368    return !D->isExternallyVisible();
1369  }
1370  
1371  // FIXME: This needs to be refactored; some other isInMainFile users want
1372  // these semantics.
isMainFileLoc(const Sema & S,SourceLocation Loc)1373  static bool isMainFileLoc(const Sema &S, SourceLocation Loc) {
1374    if (S.TUKind != TU_Complete)
1375      return false;
1376    return S.SourceMgr.isInMainFile(Loc);
1377  }
1378  
ShouldWarnIfUnusedFileScopedDecl(const DeclaratorDecl * D) const1379  bool Sema::ShouldWarnIfUnusedFileScopedDecl(const DeclaratorDecl *D) const {
1380    assert(D);
1381  
1382    if (D->isInvalidDecl() || D->isUsed() || D->hasAttr<UnusedAttr>())
1383      return false;
1384  
1385    // Ignore all entities declared within templates, and out-of-line definitions
1386    // of members of class templates.
1387    if (D->getDeclContext()->isDependentContext() ||
1388        D->getLexicalDeclContext()->isDependentContext())
1389      return false;
1390  
1391    if (const FunctionDecl *FD = dyn_cast<FunctionDecl>(D)) {
1392      if (FD->getTemplateSpecializationKind() == TSK_ImplicitInstantiation)
1393        return false;
1394  
1395      if (const CXXMethodDecl *MD = dyn_cast<CXXMethodDecl>(FD)) {
1396        if (MD->isVirtual() || IsDisallowedCopyOrAssign(MD))
1397          return false;
1398      } else {
1399        // 'static inline' functions are defined in headers; don't warn.
1400        if (FD->isInlined() && !isMainFileLoc(*this, FD->getLocation()))
1401          return false;
1402      }
1403  
1404      if (FD->doesThisDeclarationHaveABody() &&
1405          Context.DeclMustBeEmitted(FD))
1406        return false;
1407    } else if (const VarDecl *VD = dyn_cast<VarDecl>(D)) {
1408      // Constants and utility variables are defined in headers with internal
1409      // linkage; don't warn.  (Unlike functions, there isn't a convenient marker
1410      // like "inline".)
1411      if (!isMainFileLoc(*this, VD->getLocation()))
1412        return false;
1413  
1414      if (Context.DeclMustBeEmitted(VD))
1415        return false;
1416  
1417      if (VD->isStaticDataMember() &&
1418          VD->getTemplateSpecializationKind() == TSK_ImplicitInstantiation)
1419        return false;
1420    } else {
1421      return false;
1422    }
1423  
1424    // Only warn for unused decls internal to the translation unit.
1425    // FIXME: This seems like a bogus check; it suppresses -Wunused-function
1426    // for inline functions defined in the main source file, for instance.
1427    return mightHaveNonExternalLinkage(D);
1428  }
1429  
MarkUnusedFileScopedDecl(const DeclaratorDecl * D)1430  void Sema::MarkUnusedFileScopedDecl(const DeclaratorDecl *D) {
1431    if (!D)
1432      return;
1433  
1434    if (const FunctionDecl *FD = dyn_cast<FunctionDecl>(D)) {
1435      const FunctionDecl *First = FD->getFirstDecl();
1436      if (FD != First && ShouldWarnIfUnusedFileScopedDecl(First))
1437        return; // First should already be in the vector.
1438    }
1439  
1440    if (const VarDecl *VD = dyn_cast<VarDecl>(D)) {
1441      const VarDecl *First = VD->getFirstDecl();
1442      if (VD != First && ShouldWarnIfUnusedFileScopedDecl(First))
1443        return; // First should already be in the vector.
1444    }
1445  
1446    if (ShouldWarnIfUnusedFileScopedDecl(D))
1447      UnusedFileScopedDecls.push_back(D);
1448  }
1449  
ShouldDiagnoseUnusedDecl(const NamedDecl * D)1450  static bool ShouldDiagnoseUnusedDecl(const NamedDecl *D) {
1451    if (D->isInvalidDecl())
1452      return false;
1453  
1454    if (D->isReferenced() || D->isUsed() || D->hasAttr<UnusedAttr>() ||
1455        D->hasAttr<ObjCPreciseLifetimeAttr>())
1456      return false;
1457  
1458    if (isa<LabelDecl>(D))
1459      return true;
1460  
1461    // Except for labels, we only care about unused decls that are local to
1462    // functions.
1463    bool WithinFunction = D->getDeclContext()->isFunctionOrMethod();
1464    if (const auto *R = dyn_cast<CXXRecordDecl>(D->getDeclContext()))
1465      // For dependent types, the diagnostic is deferred.
1466      WithinFunction =
1467          WithinFunction || (R->isLocalClass() && !R->isDependentType());
1468    if (!WithinFunction)
1469      return false;
1470  
1471    if (isa<TypedefNameDecl>(D))
1472      return true;
1473  
1474    // White-list anything that isn't a local variable.
1475    if (!isa<VarDecl>(D) || isa<ParmVarDecl>(D) || isa<ImplicitParamDecl>(D))
1476      return false;
1477  
1478    // Types of valid local variables should be complete, so this should succeed.
1479    if (const VarDecl *VD = dyn_cast<VarDecl>(D)) {
1480  
1481      // White-list anything with an __attribute__((unused)) type.
1482      QualType Ty = VD->getType();
1483  
1484      // Only look at the outermost level of typedef.
1485      if (const TypedefType *TT = Ty->getAs<TypedefType>()) {
1486        if (TT->getDecl()->hasAttr<UnusedAttr>())
1487          return false;
1488      }
1489  
1490      // If we failed to complete the type for some reason, or if the type is
1491      // dependent, don't diagnose the variable.
1492      if (Ty->isIncompleteType() || Ty->isDependentType())
1493        return false;
1494  
1495      if (const TagType *TT = Ty->getAs<TagType>()) {
1496        const TagDecl *Tag = TT->getDecl();
1497        if (Tag->hasAttr<UnusedAttr>())
1498          return false;
1499  
1500        if (const CXXRecordDecl *RD = dyn_cast<CXXRecordDecl>(Tag)) {
1501          if (!RD->hasTrivialDestructor() && !RD->hasAttr<WarnUnusedAttr>())
1502            return false;
1503  
1504          if (const Expr *Init = VD->getInit()) {
1505            if (const ExprWithCleanups *Cleanups =
1506                    dyn_cast<ExprWithCleanups>(Init))
1507              Init = Cleanups->getSubExpr();
1508            const CXXConstructExpr *Construct =
1509              dyn_cast<CXXConstructExpr>(Init);
1510            if (Construct && !Construct->isElidable()) {
1511              CXXConstructorDecl *CD = Construct->getConstructor();
1512              if (!CD->isTrivial() && !RD->hasAttr<WarnUnusedAttr>())
1513                return false;
1514            }
1515          }
1516        }
1517      }
1518  
1519      // TODO: __attribute__((unused)) templates?
1520    }
1521  
1522    return true;
1523  }
1524  
GenerateFixForUnusedDecl(const NamedDecl * D,ASTContext & Ctx,FixItHint & Hint)1525  static void GenerateFixForUnusedDecl(const NamedDecl *D, ASTContext &Ctx,
1526                                       FixItHint &Hint) {
1527    if (isa<LabelDecl>(D)) {
1528      SourceLocation AfterColon = Lexer::findLocationAfterToken(D->getLocEnd(),
1529                  tok::colon, Ctx.getSourceManager(), Ctx.getLangOpts(), true);
1530      if (AfterColon.isInvalid())
1531        return;
1532      Hint = FixItHint::CreateRemoval(CharSourceRange::
1533                                      getCharRange(D->getLocStart(), AfterColon));
1534    }
1535    return;
1536  }
1537  
DiagnoseUnusedNestedTypedefs(const RecordDecl * D)1538  void Sema::DiagnoseUnusedNestedTypedefs(const RecordDecl *D) {
1539    if (D->getTypeForDecl()->isDependentType())
1540      return;
1541  
1542    for (auto *TmpD : D->decls()) {
1543      if (const auto *T = dyn_cast<TypedefNameDecl>(TmpD))
1544        DiagnoseUnusedDecl(T);
1545      else if(const auto *R = dyn_cast<RecordDecl>(TmpD))
1546        DiagnoseUnusedNestedTypedefs(R);
1547    }
1548  }
1549  
1550  /// DiagnoseUnusedDecl - Emit warnings about declarations that are not used
1551  /// unless they are marked attr(unused).
DiagnoseUnusedDecl(const NamedDecl * D)1552  void Sema::DiagnoseUnusedDecl(const NamedDecl *D) {
1553    if (!ShouldDiagnoseUnusedDecl(D))
1554      return;
1555  
1556    if (auto *TD = dyn_cast<TypedefNameDecl>(D)) {
1557      // typedefs can be referenced later on, so the diagnostics are emitted
1558      // at end-of-translation-unit.
1559      UnusedLocalTypedefNameCandidates.insert(TD);
1560      return;
1561    }
1562  
1563    FixItHint Hint;
1564    GenerateFixForUnusedDecl(D, Context, Hint);
1565  
1566    unsigned DiagID;
1567    if (isa<VarDecl>(D) && cast<VarDecl>(D)->isExceptionVariable())
1568      DiagID = diag::warn_unused_exception_param;
1569    else if (isa<LabelDecl>(D))
1570      DiagID = diag::warn_unused_label;
1571    else
1572      DiagID = diag::warn_unused_variable;
1573  
1574    Diag(D->getLocation(), DiagID) << D->getDeclName() << Hint;
1575  }
1576  
CheckPoppedLabel(LabelDecl * L,Sema & S)1577  static void CheckPoppedLabel(LabelDecl *L, Sema &S) {
1578    // Verify that we have no forward references left.  If so, there was a goto
1579    // or address of a label taken, but no definition of it.  Label fwd
1580    // definitions are indicated with a null substmt which is also not a resolved
1581    // MS inline assembly label name.
1582    bool Diagnose = false;
1583    if (L->isMSAsmLabel())
1584      Diagnose = !L->isResolvedMSAsmLabel();
1585    else
1586      Diagnose = L->getStmt() == nullptr;
1587    if (Diagnose)
1588      S.Diag(L->getLocation(), diag::err_undeclared_label_use) <<L->getDeclName();
1589  }
1590  
ActOnPopScope(SourceLocation Loc,Scope * S)1591  void Sema::ActOnPopScope(SourceLocation Loc, Scope *S) {
1592    S->mergeNRVOIntoParent();
1593  
1594    if (S->decl_empty()) return;
1595    assert((S->getFlags() & (Scope::DeclScope | Scope::TemplateParamScope)) &&
1596           "Scope shouldn't contain decls!");
1597  
1598    for (auto *TmpD : S->decls()) {
1599      assert(TmpD && "This decl didn't get pushed??");
1600  
1601      assert(isa<NamedDecl>(TmpD) && "Decl isn't NamedDecl?");
1602      NamedDecl *D = cast<NamedDecl>(TmpD);
1603  
1604      if (!D->getDeclName()) continue;
1605  
1606      // Diagnose unused variables in this scope.
1607      if (!S->hasUnrecoverableErrorOccurred()) {
1608        DiagnoseUnusedDecl(D);
1609        if (const auto *RD = dyn_cast<RecordDecl>(D))
1610          DiagnoseUnusedNestedTypedefs(RD);
1611      }
1612  
1613      // If this was a forward reference to a label, verify it was defined.
1614      if (LabelDecl *LD = dyn_cast<LabelDecl>(D))
1615        CheckPoppedLabel(LD, *this);
1616  
1617      // Remove this name from our lexical scope.
1618      IdResolver.RemoveDecl(D);
1619    }
1620  }
1621  
1622  /// \brief Look for an Objective-C class in the translation unit.
1623  ///
1624  /// \param Id The name of the Objective-C class we're looking for. If
1625  /// typo-correction fixes this name, the Id will be updated
1626  /// to the fixed name.
1627  ///
1628  /// \param IdLoc The location of the name in the translation unit.
1629  ///
1630  /// \param DoTypoCorrection If true, this routine will attempt typo correction
1631  /// if there is no class with the given name.
1632  ///
1633  /// \returns The declaration of the named Objective-C class, or NULL if the
1634  /// class could not be found.
getObjCInterfaceDecl(IdentifierInfo * & Id,SourceLocation IdLoc,bool DoTypoCorrection)1635  ObjCInterfaceDecl *Sema::getObjCInterfaceDecl(IdentifierInfo *&Id,
1636                                                SourceLocation IdLoc,
1637                                                bool DoTypoCorrection) {
1638    // The third "scope" argument is 0 since we aren't enabling lazy built-in
1639    // creation from this context.
1640    NamedDecl *IDecl = LookupSingleName(TUScope, Id, IdLoc, LookupOrdinaryName);
1641  
1642    if (!IDecl && DoTypoCorrection) {
1643      // Perform typo correction at the given location, but only if we
1644      // find an Objective-C class name.
1645      if (TypoCorrection C = CorrectTypo(
1646              DeclarationNameInfo(Id, IdLoc), LookupOrdinaryName, TUScope, nullptr,
1647              llvm::make_unique<DeclFilterCCC<ObjCInterfaceDecl>>(),
1648              CTK_ErrorRecovery)) {
1649        diagnoseTypo(C, PDiag(diag::err_undef_interface_suggest) << Id);
1650        IDecl = C.getCorrectionDeclAs<ObjCInterfaceDecl>();
1651        Id = IDecl->getIdentifier();
1652      }
1653    }
1654    ObjCInterfaceDecl *Def = dyn_cast_or_null<ObjCInterfaceDecl>(IDecl);
1655    // This routine must always return a class definition, if any.
1656    if (Def && Def->getDefinition())
1657        Def = Def->getDefinition();
1658    return Def;
1659  }
1660  
1661  /// getNonFieldDeclScope - Retrieves the innermost scope, starting
1662  /// from S, where a non-field would be declared. This routine copes
1663  /// with the difference between C and C++ scoping rules in structs and
1664  /// unions. For example, the following code is well-formed in C but
1665  /// ill-formed in C++:
1666  /// @code
1667  /// struct S6 {
1668  ///   enum { BAR } e;
1669  /// };
1670  ///
1671  /// void test_S6() {
1672  ///   struct S6 a;
1673  ///   a.e = BAR;
1674  /// }
1675  /// @endcode
1676  /// For the declaration of BAR, this routine will return a different
1677  /// scope. The scope S will be the scope of the unnamed enumeration
1678  /// within S6. In C++, this routine will return the scope associated
1679  /// with S6, because the enumeration's scope is a transparent
1680  /// context but structures can contain non-field names. In C, this
1681  /// routine will return the translation unit scope, since the
1682  /// enumeration's scope is a transparent context and structures cannot
1683  /// contain non-field names.
getNonFieldDeclScope(Scope * S)1684  Scope *Sema::getNonFieldDeclScope(Scope *S) {
1685    while (((S->getFlags() & Scope::DeclScope) == 0) ||
1686           (S->getEntity() && S->getEntity()->isTransparentContext()) ||
1687           (S->isClassScope() && !getLangOpts().CPlusPlus))
1688      S = S->getParent();
1689    return S;
1690  }
1691  
1692  /// \brief Looks up the declaration of "struct objc_super" and
1693  /// saves it for later use in building builtin declaration of
1694  /// objc_msgSendSuper and objc_msgSendSuper_stret. If no such
1695  /// pre-existing declaration exists no action takes place.
LookupPredefedObjCSuperType(Sema & ThisSema,Scope * S,IdentifierInfo * II)1696  static void LookupPredefedObjCSuperType(Sema &ThisSema, Scope *S,
1697                                          IdentifierInfo *II) {
1698    if (!II->isStr("objc_msgSendSuper"))
1699      return;
1700    ASTContext &Context = ThisSema.Context;
1701  
1702    LookupResult Result(ThisSema, &Context.Idents.get("objc_super"),
1703                        SourceLocation(), Sema::LookupTagName);
1704    ThisSema.LookupName(Result, S);
1705    if (Result.getResultKind() == LookupResult::Found)
1706      if (const TagDecl *TD = Result.getAsSingle<TagDecl>())
1707        Context.setObjCSuperType(Context.getTagDeclType(TD));
1708  }
1709  
getHeaderName(ASTContext::GetBuiltinTypeError Error)1710  static StringRef getHeaderName(ASTContext::GetBuiltinTypeError Error) {
1711    switch (Error) {
1712    case ASTContext::GE_None:
1713      return "";
1714    case ASTContext::GE_Missing_stdio:
1715      return "stdio.h";
1716    case ASTContext::GE_Missing_setjmp:
1717      return "setjmp.h";
1718    case ASTContext::GE_Missing_ucontext:
1719      return "ucontext.h";
1720    }
1721    llvm_unreachable("unhandled error kind");
1722  }
1723  
1724  /// LazilyCreateBuiltin - The specified Builtin-ID was first used at
1725  /// file scope.  lazily create a decl for it. ForRedeclaration is true
1726  /// if we're creating this built-in in anticipation of redeclaring the
1727  /// built-in.
LazilyCreateBuiltin(IdentifierInfo * II,unsigned ID,Scope * S,bool ForRedeclaration,SourceLocation Loc)1728  NamedDecl *Sema::LazilyCreateBuiltin(IdentifierInfo *II, unsigned ID,
1729                                       Scope *S, bool ForRedeclaration,
1730                                       SourceLocation Loc) {
1731    LookupPredefedObjCSuperType(*this, S, II);
1732  
1733    ASTContext::GetBuiltinTypeError Error;
1734    QualType R = Context.GetBuiltinType(ID, Error);
1735    if (Error) {
1736      if (ForRedeclaration)
1737        Diag(Loc, diag::warn_implicit_decl_requires_sysheader)
1738            << getHeaderName(Error) << Context.BuiltinInfo.getName(ID);
1739      return nullptr;
1740    }
1741  
1742    if (!ForRedeclaration && Context.BuiltinInfo.isPredefinedLibFunction(ID)) {
1743      Diag(Loc, diag::ext_implicit_lib_function_decl)
1744          << Context.BuiltinInfo.getName(ID) << R;
1745      if (Context.BuiltinInfo.getHeaderName(ID) &&
1746          !Diags.isIgnored(diag::ext_implicit_lib_function_decl, Loc))
1747        Diag(Loc, diag::note_include_header_or_declare)
1748            << Context.BuiltinInfo.getHeaderName(ID)
1749            << Context.BuiltinInfo.getName(ID);
1750    }
1751  
1752    DeclContext *Parent = Context.getTranslationUnitDecl();
1753    if (getLangOpts().CPlusPlus) {
1754      LinkageSpecDecl *CLinkageDecl =
1755          LinkageSpecDecl::Create(Context, Parent, Loc, Loc,
1756                                  LinkageSpecDecl::lang_c, false);
1757      CLinkageDecl->setImplicit();
1758      Parent->addDecl(CLinkageDecl);
1759      Parent = CLinkageDecl;
1760    }
1761  
1762    FunctionDecl *New = FunctionDecl::Create(Context,
1763                                             Parent,
1764                                             Loc, Loc, II, R, /*TInfo=*/nullptr,
1765                                             SC_Extern,
1766                                             false,
1767                                             R->isFunctionProtoType());
1768    New->setImplicit();
1769  
1770    // Create Decl objects for each parameter, adding them to the
1771    // FunctionDecl.
1772    if (const FunctionProtoType *FT = dyn_cast<FunctionProtoType>(R)) {
1773      SmallVector<ParmVarDecl*, 16> Params;
1774      for (unsigned i = 0, e = FT->getNumParams(); i != e; ++i) {
1775        ParmVarDecl *parm =
1776            ParmVarDecl::Create(Context, New, SourceLocation(), SourceLocation(),
1777                                nullptr, FT->getParamType(i), /*TInfo=*/nullptr,
1778                                SC_None, nullptr);
1779        parm->setScopeInfo(0, i);
1780        Params.push_back(parm);
1781      }
1782      New->setParams(Params);
1783    }
1784  
1785    AddKnownFunctionAttributes(New);
1786    RegisterLocallyScopedExternCDecl(New, S);
1787  
1788    // TUScope is the translation-unit scope to insert this function into.
1789    // FIXME: This is hideous. We need to teach PushOnScopeChains to
1790    // relate Scopes to DeclContexts, and probably eliminate CurContext
1791    // entirely, but we're not there yet.
1792    DeclContext *SavedContext = CurContext;
1793    CurContext = Parent;
1794    PushOnScopeChains(New, TUScope);
1795    CurContext = SavedContext;
1796    return New;
1797  }
1798  
1799  /// Typedef declarations don't have linkage, but they still denote the same
1800  /// entity if their types are the same.
1801  /// FIXME: This is notionally doing the same thing as ASTReaderDecl's
1802  /// isSameEntity.
filterNonConflictingPreviousTypedefDecls(Sema & S,TypedefNameDecl * Decl,LookupResult & Previous)1803  static void filterNonConflictingPreviousTypedefDecls(Sema &S,
1804                                                       TypedefNameDecl *Decl,
1805                                                       LookupResult &Previous) {
1806    // This is only interesting when modules are enabled.
1807    if (!S.getLangOpts().Modules && !S.getLangOpts().ModulesLocalVisibility)
1808      return;
1809  
1810    // Empty sets are uninteresting.
1811    if (Previous.empty())
1812      return;
1813  
1814    LookupResult::Filter Filter = Previous.makeFilter();
1815    while (Filter.hasNext()) {
1816      NamedDecl *Old = Filter.next();
1817  
1818      // Non-hidden declarations are never ignored.
1819      if (S.isVisible(Old))
1820        continue;
1821  
1822      // Declarations of the same entity are not ignored, even if they have
1823      // different linkages.
1824      if (auto *OldTD = dyn_cast<TypedefNameDecl>(Old)) {
1825        if (S.Context.hasSameType(OldTD->getUnderlyingType(),
1826                                  Decl->getUnderlyingType()))
1827          continue;
1828  
1829        // If both declarations give a tag declaration a typedef name for linkage
1830        // purposes, then they declare the same entity.
1831        if (S.getLangOpts().CPlusPlus &&
1832            OldTD->getAnonDeclWithTypedefName(/*AnyRedecl*/true) &&
1833            Decl->getAnonDeclWithTypedefName())
1834          continue;
1835      }
1836  
1837      Filter.erase();
1838    }
1839  
1840    Filter.done();
1841  }
1842  
isIncompatibleTypedef(TypeDecl * Old,TypedefNameDecl * New)1843  bool Sema::isIncompatibleTypedef(TypeDecl *Old, TypedefNameDecl *New) {
1844    QualType OldType;
1845    if (TypedefNameDecl *OldTypedef = dyn_cast<TypedefNameDecl>(Old))
1846      OldType = OldTypedef->getUnderlyingType();
1847    else
1848      OldType = Context.getTypeDeclType(Old);
1849    QualType NewType = New->getUnderlyingType();
1850  
1851    if (NewType->isVariablyModifiedType()) {
1852      // Must not redefine a typedef with a variably-modified type.
1853      int Kind = isa<TypeAliasDecl>(Old) ? 1 : 0;
1854      Diag(New->getLocation(), diag::err_redefinition_variably_modified_typedef)
1855        << Kind << NewType;
1856      if (Old->getLocation().isValid())
1857        Diag(Old->getLocation(), diag::note_previous_definition);
1858      New->setInvalidDecl();
1859      return true;
1860    }
1861  
1862    if (OldType != NewType &&
1863        !OldType->isDependentType() &&
1864        !NewType->isDependentType() &&
1865        !Context.hasSameType(OldType, NewType)) {
1866      int Kind = isa<TypeAliasDecl>(Old) ? 1 : 0;
1867      Diag(New->getLocation(), diag::err_redefinition_different_typedef)
1868        << Kind << NewType << OldType;
1869      if (Old->getLocation().isValid())
1870        Diag(Old->getLocation(), diag::note_previous_definition);
1871      New->setInvalidDecl();
1872      return true;
1873    }
1874    return false;
1875  }
1876  
1877  /// MergeTypedefNameDecl - We just parsed a typedef 'New' which has the
1878  /// same name and scope as a previous declaration 'Old'.  Figure out
1879  /// how to resolve this situation, merging decls or emitting
1880  /// diagnostics as appropriate. If there was an error, set New to be invalid.
1881  ///
MergeTypedefNameDecl(Scope * S,TypedefNameDecl * New,LookupResult & OldDecls)1882  void Sema::MergeTypedefNameDecl(Scope *S, TypedefNameDecl *New,
1883                                  LookupResult &OldDecls) {
1884    // If the new decl is known invalid already, don't bother doing any
1885    // merging checks.
1886    if (New->isInvalidDecl()) return;
1887  
1888    // Allow multiple definitions for ObjC built-in typedefs.
1889    // FIXME: Verify the underlying types are equivalent!
1890    if (getLangOpts().ObjC1) {
1891      const IdentifierInfo *TypeID = New->getIdentifier();
1892      switch (TypeID->getLength()) {
1893      default: break;
1894      case 2:
1895        {
1896          if (!TypeID->isStr("id"))
1897            break;
1898          QualType T = New->getUnderlyingType();
1899          if (!T->isPointerType())
1900            break;
1901          if (!T->isVoidPointerType()) {
1902            QualType PT = T->getAs<PointerType>()->getPointeeType();
1903            if (!PT->isStructureType())
1904              break;
1905          }
1906          Context.setObjCIdRedefinitionType(T);
1907          // Install the built-in type for 'id', ignoring the current definition.
1908          New->setTypeForDecl(Context.getObjCIdType().getTypePtr());
1909          return;
1910        }
1911      case 5:
1912        if (!TypeID->isStr("Class"))
1913          break;
1914        Context.setObjCClassRedefinitionType(New->getUnderlyingType());
1915        // Install the built-in type for 'Class', ignoring the current definition.
1916        New->setTypeForDecl(Context.getObjCClassType().getTypePtr());
1917        return;
1918      case 3:
1919        if (!TypeID->isStr("SEL"))
1920          break;
1921        Context.setObjCSelRedefinitionType(New->getUnderlyingType());
1922        // Install the built-in type for 'SEL', ignoring the current definition.
1923        New->setTypeForDecl(Context.getObjCSelType().getTypePtr());
1924        return;
1925      }
1926      // Fall through - the typedef name was not a builtin type.
1927    }
1928  
1929    // Verify the old decl was also a type.
1930    TypeDecl *Old = OldDecls.getAsSingle<TypeDecl>();
1931    if (!Old) {
1932      Diag(New->getLocation(), diag::err_redefinition_different_kind)
1933        << New->getDeclName();
1934  
1935      NamedDecl *OldD = OldDecls.getRepresentativeDecl();
1936      if (OldD->getLocation().isValid())
1937        Diag(OldD->getLocation(), diag::note_previous_definition);
1938  
1939      return New->setInvalidDecl();
1940    }
1941  
1942    // If the old declaration is invalid, just give up here.
1943    if (Old->isInvalidDecl())
1944      return New->setInvalidDecl();
1945  
1946    if (auto *OldTD = dyn_cast<TypedefNameDecl>(Old)) {
1947      auto *OldTag = OldTD->getAnonDeclWithTypedefName(/*AnyRedecl*/true);
1948      auto *NewTag = New->getAnonDeclWithTypedefName();
1949      NamedDecl *Hidden = nullptr;
1950      if (getLangOpts().CPlusPlus && OldTag && NewTag &&
1951          OldTag->getCanonicalDecl() != NewTag->getCanonicalDecl() &&
1952          !hasVisibleDefinition(OldTag, &Hidden)) {
1953        // There is a definition of this tag, but it is not visible. Use it
1954        // instead of our tag.
1955        New->setTypeForDecl(OldTD->getTypeForDecl());
1956        if (OldTD->isModed())
1957          New->setModedTypeSourceInfo(OldTD->getTypeSourceInfo(),
1958                                      OldTD->getUnderlyingType());
1959        else
1960          New->setTypeSourceInfo(OldTD->getTypeSourceInfo());
1961  
1962        // Make the old tag definition visible.
1963        makeMergedDefinitionVisible(Hidden, NewTag->getLocation());
1964  
1965        // If this was an unscoped enumeration, yank all of its enumerators
1966        // out of the scope.
1967        if (isa<EnumDecl>(NewTag)) {
1968          Scope *EnumScope = getNonFieldDeclScope(S);
1969          for (auto *D : NewTag->decls()) {
1970            auto *ED = cast<EnumConstantDecl>(D);
1971            assert(EnumScope->isDeclScope(ED));
1972            EnumScope->RemoveDecl(ED);
1973            IdResolver.RemoveDecl(ED);
1974            ED->getLexicalDeclContext()->removeDecl(ED);
1975          }
1976        }
1977      }
1978    }
1979  
1980    // If the typedef types are not identical, reject them in all languages and
1981    // with any extensions enabled.
1982    if (isIncompatibleTypedef(Old, New))
1983      return;
1984  
1985    // The types match.  Link up the redeclaration chain and merge attributes if
1986    // the old declaration was a typedef.
1987    if (TypedefNameDecl *Typedef = dyn_cast<TypedefNameDecl>(Old)) {
1988      New->setPreviousDecl(Typedef);
1989      mergeDeclAttributes(New, Old);
1990    }
1991  
1992    if (getLangOpts().MicrosoftExt)
1993      return;
1994  
1995    if (getLangOpts().CPlusPlus) {
1996      // C++ [dcl.typedef]p2:
1997      //   In a given non-class scope, a typedef specifier can be used to
1998      //   redefine the name of any type declared in that scope to refer
1999      //   to the type to which it already refers.
2000      if (!isa<CXXRecordDecl>(CurContext))
2001        return;
2002  
2003      // C++0x [dcl.typedef]p4:
2004      //   In a given class scope, a typedef specifier can be used to redefine
2005      //   any class-name declared in that scope that is not also a typedef-name
2006      //   to refer to the type to which it already refers.
2007      //
2008      // This wording came in via DR424, which was a correction to the
2009      // wording in DR56, which accidentally banned code like:
2010      //
2011      //   struct S {
2012      //     typedef struct A { } A;
2013      //   };
2014      //
2015      // in the C++03 standard. We implement the C++0x semantics, which
2016      // allow the above but disallow
2017      //
2018      //   struct S {
2019      //     typedef int I;
2020      //     typedef int I;
2021      //   };
2022      //
2023      // since that was the intent of DR56.
2024      if (!isa<TypedefNameDecl>(Old))
2025        return;
2026  
2027      Diag(New->getLocation(), diag::err_redefinition)
2028        << New->getDeclName();
2029      Diag(Old->getLocation(), diag::note_previous_definition);
2030      return New->setInvalidDecl();
2031    }
2032  
2033    // Modules always permit redefinition of typedefs, as does C11.
2034    if (getLangOpts().Modules || getLangOpts().C11)
2035      return;
2036  
2037    // If we have a redefinition of a typedef in C, emit a warning.  This warning
2038    // is normally mapped to an error, but can be controlled with
2039    // -Wtypedef-redefinition.  If either the original or the redefinition is
2040    // in a system header, don't emit this for compatibility with GCC.
2041    if (getDiagnostics().getSuppressSystemWarnings() &&
2042        (Context.getSourceManager().isInSystemHeader(Old->getLocation()) ||
2043         Context.getSourceManager().isInSystemHeader(New->getLocation())))
2044      return;
2045  
2046    Diag(New->getLocation(), diag::ext_redefinition_of_typedef)
2047      << New->getDeclName();
2048    Diag(Old->getLocation(), diag::note_previous_definition);
2049  }
2050  
2051  /// DeclhasAttr - returns true if decl Declaration already has the target
2052  /// attribute.
DeclHasAttr(const Decl * D,const Attr * A)2053  static bool DeclHasAttr(const Decl *D, const Attr *A) {
2054    const OwnershipAttr *OA = dyn_cast<OwnershipAttr>(A);
2055    const AnnotateAttr *Ann = dyn_cast<AnnotateAttr>(A);
2056    for (const auto *i : D->attrs())
2057      if (i->getKind() == A->getKind()) {
2058        if (Ann) {
2059          if (Ann->getAnnotation() == cast<AnnotateAttr>(i)->getAnnotation())
2060            return true;
2061          continue;
2062        }
2063        // FIXME: Don't hardcode this check
2064        if (OA && isa<OwnershipAttr>(i))
2065          return OA->getOwnKind() == cast<OwnershipAttr>(i)->getOwnKind();
2066        return true;
2067      }
2068  
2069    return false;
2070  }
2071  
isAttributeTargetADefinition(Decl * D)2072  static bool isAttributeTargetADefinition(Decl *D) {
2073    if (VarDecl *VD = dyn_cast<VarDecl>(D))
2074      return VD->isThisDeclarationADefinition();
2075    if (TagDecl *TD = dyn_cast<TagDecl>(D))
2076      return TD->isCompleteDefinition() || TD->isBeingDefined();
2077    return true;
2078  }
2079  
2080  /// Merge alignment attributes from \p Old to \p New, taking into account the
2081  /// special semantics of C11's _Alignas specifier and C++11's alignas attribute.
2082  ///
2083  /// \return \c true if any attributes were added to \p New.
mergeAlignedAttrs(Sema & S,NamedDecl * New,Decl * Old)2084  static bool mergeAlignedAttrs(Sema &S, NamedDecl *New, Decl *Old) {
2085    // Look for alignas attributes on Old, and pick out whichever attribute
2086    // specifies the strictest alignment requirement.
2087    AlignedAttr *OldAlignasAttr = nullptr;
2088    AlignedAttr *OldStrictestAlignAttr = nullptr;
2089    unsigned OldAlign = 0;
2090    for (auto *I : Old->specific_attrs<AlignedAttr>()) {
2091      // FIXME: We have no way of representing inherited dependent alignments
2092      // in a case like:
2093      //   template<int A, int B> struct alignas(A) X;
2094      //   template<int A, int B> struct alignas(B) X {};
2095      // For now, we just ignore any alignas attributes which are not on the
2096      // definition in such a case.
2097      if (I->isAlignmentDependent())
2098        return false;
2099  
2100      if (I->isAlignas())
2101        OldAlignasAttr = I;
2102  
2103      unsigned Align = I->getAlignment(S.Context);
2104      if (Align > OldAlign) {
2105        OldAlign = Align;
2106        OldStrictestAlignAttr = I;
2107      }
2108    }
2109  
2110    // Look for alignas attributes on New.
2111    AlignedAttr *NewAlignasAttr = nullptr;
2112    unsigned NewAlign = 0;
2113    for (auto *I : New->specific_attrs<AlignedAttr>()) {
2114      if (I->isAlignmentDependent())
2115        return false;
2116  
2117      if (I->isAlignas())
2118        NewAlignasAttr = I;
2119  
2120      unsigned Align = I->getAlignment(S.Context);
2121      if (Align > NewAlign)
2122        NewAlign = Align;
2123    }
2124  
2125    if (OldAlignasAttr && NewAlignasAttr && OldAlign != NewAlign) {
2126      // Both declarations have 'alignas' attributes. We require them to match.
2127      // C++11 [dcl.align]p6 and C11 6.7.5/7 both come close to saying this, but
2128      // fall short. (If two declarations both have alignas, they must both match
2129      // every definition, and so must match each other if there is a definition.)
2130  
2131      // If either declaration only contains 'alignas(0)' specifiers, then it
2132      // specifies the natural alignment for the type.
2133      if (OldAlign == 0 || NewAlign == 0) {
2134        QualType Ty;
2135        if (ValueDecl *VD = dyn_cast<ValueDecl>(New))
2136          Ty = VD->getType();
2137        else
2138          Ty = S.Context.getTagDeclType(cast<TagDecl>(New));
2139  
2140        if (OldAlign == 0)
2141          OldAlign = S.Context.getTypeAlign(Ty);
2142        if (NewAlign == 0)
2143          NewAlign = S.Context.getTypeAlign(Ty);
2144      }
2145  
2146      if (OldAlign != NewAlign) {
2147        S.Diag(NewAlignasAttr->getLocation(), diag::err_alignas_mismatch)
2148          << (unsigned)S.Context.toCharUnitsFromBits(OldAlign).getQuantity()
2149          << (unsigned)S.Context.toCharUnitsFromBits(NewAlign).getQuantity();
2150        S.Diag(OldAlignasAttr->getLocation(), diag::note_previous_declaration);
2151      }
2152    }
2153  
2154    if (OldAlignasAttr && !NewAlignasAttr && isAttributeTargetADefinition(New)) {
2155      // C++11 [dcl.align]p6:
2156      //   if any declaration of an entity has an alignment-specifier,
2157      //   every defining declaration of that entity shall specify an
2158      //   equivalent alignment.
2159      // C11 6.7.5/7:
2160      //   If the definition of an object does not have an alignment
2161      //   specifier, any other declaration of that object shall also
2162      //   have no alignment specifier.
2163      S.Diag(New->getLocation(), diag::err_alignas_missing_on_definition)
2164        << OldAlignasAttr;
2165      S.Diag(OldAlignasAttr->getLocation(), diag::note_alignas_on_declaration)
2166        << OldAlignasAttr;
2167    }
2168  
2169    bool AnyAdded = false;
2170  
2171    // Ensure we have an attribute representing the strictest alignment.
2172    if (OldAlign > NewAlign) {
2173      AlignedAttr *Clone = OldStrictestAlignAttr->clone(S.Context);
2174      Clone->setInherited(true);
2175      New->addAttr(Clone);
2176      AnyAdded = true;
2177    }
2178  
2179    // Ensure we have an alignas attribute if the old declaration had one.
2180    if (OldAlignasAttr && !NewAlignasAttr &&
2181        !(AnyAdded && OldStrictestAlignAttr->isAlignas())) {
2182      AlignedAttr *Clone = OldAlignasAttr->clone(S.Context);
2183      Clone->setInherited(true);
2184      New->addAttr(Clone);
2185      AnyAdded = true;
2186    }
2187  
2188    return AnyAdded;
2189  }
2190  
mergeDeclAttribute(Sema & S,NamedDecl * D,const InheritableAttr * Attr,Sema::AvailabilityMergeKind AMK)2191  static bool mergeDeclAttribute(Sema &S, NamedDecl *D,
2192                                 const InheritableAttr *Attr,
2193                                 Sema::AvailabilityMergeKind AMK) {
2194    InheritableAttr *NewAttr = nullptr;
2195    unsigned AttrSpellingListIndex = Attr->getSpellingListIndex();
2196    if (const auto *AA = dyn_cast<AvailabilityAttr>(Attr))
2197      NewAttr = S.mergeAvailabilityAttr(D, AA->getRange(), AA->getPlatform(),
2198                                        AA->getIntroduced(), AA->getDeprecated(),
2199                                        AA->getObsoleted(), AA->getUnavailable(),
2200                                        AA->getMessage(), AMK,
2201                                        AttrSpellingListIndex);
2202    else if (const auto *VA = dyn_cast<VisibilityAttr>(Attr))
2203      NewAttr = S.mergeVisibilityAttr(D, VA->getRange(), VA->getVisibility(),
2204                                      AttrSpellingListIndex);
2205    else if (const auto *VA = dyn_cast<TypeVisibilityAttr>(Attr))
2206      NewAttr = S.mergeTypeVisibilityAttr(D, VA->getRange(), VA->getVisibility(),
2207                                          AttrSpellingListIndex);
2208    else if (const auto *ImportA = dyn_cast<DLLImportAttr>(Attr))
2209      NewAttr = S.mergeDLLImportAttr(D, ImportA->getRange(),
2210                                     AttrSpellingListIndex);
2211    else if (const auto *ExportA = dyn_cast<DLLExportAttr>(Attr))
2212      NewAttr = S.mergeDLLExportAttr(D, ExportA->getRange(),
2213                                     AttrSpellingListIndex);
2214    else if (const auto *FA = dyn_cast<FormatAttr>(Attr))
2215      NewAttr = S.mergeFormatAttr(D, FA->getRange(), FA->getType(),
2216                                  FA->getFormatIdx(), FA->getFirstArg(),
2217                                  AttrSpellingListIndex);
2218    else if (const auto *SA = dyn_cast<SectionAttr>(Attr))
2219      NewAttr = S.mergeSectionAttr(D, SA->getRange(), SA->getName(),
2220                                   AttrSpellingListIndex);
2221    else if (const auto *IA = dyn_cast<MSInheritanceAttr>(Attr))
2222      NewAttr = S.mergeMSInheritanceAttr(D, IA->getRange(), IA->getBestCase(),
2223                                         AttrSpellingListIndex,
2224                                         IA->getSemanticSpelling());
2225    else if (const auto *AA = dyn_cast<AlwaysInlineAttr>(Attr))
2226      NewAttr = S.mergeAlwaysInlineAttr(D, AA->getRange(),
2227                                        &S.Context.Idents.get(AA->getSpelling()),
2228                                        AttrSpellingListIndex);
2229    else if (const auto *MA = dyn_cast<MinSizeAttr>(Attr))
2230      NewAttr = S.mergeMinSizeAttr(D, MA->getRange(), AttrSpellingListIndex);
2231    else if (const auto *OA = dyn_cast<OptimizeNoneAttr>(Attr))
2232      NewAttr = S.mergeOptimizeNoneAttr(D, OA->getRange(), AttrSpellingListIndex);
2233    else if (const auto *InternalLinkageA = dyn_cast<InternalLinkageAttr>(Attr))
2234      NewAttr = S.mergeInternalLinkageAttr(
2235          D, InternalLinkageA->getRange(),
2236          &S.Context.Idents.get(InternalLinkageA->getSpelling()),
2237          AttrSpellingListIndex);
2238    else if (const auto *CommonA = dyn_cast<CommonAttr>(Attr))
2239      NewAttr = S.mergeCommonAttr(D, CommonA->getRange(),
2240                                  &S.Context.Idents.get(CommonA->getSpelling()),
2241                                  AttrSpellingListIndex);
2242    else if (isa<AlignedAttr>(Attr))
2243      // AlignedAttrs are handled separately, because we need to handle all
2244      // such attributes on a declaration at the same time.
2245      NewAttr = nullptr;
2246    else if ((isa<DeprecatedAttr>(Attr) || isa<UnavailableAttr>(Attr)) &&
2247             (AMK == Sema::AMK_Override ||
2248              AMK == Sema::AMK_ProtocolImplementation))
2249      NewAttr = nullptr;
2250    else if (Attr->duplicatesAllowed() || !DeclHasAttr(D, Attr))
2251      NewAttr = cast<InheritableAttr>(Attr->clone(S.Context));
2252  
2253    if (NewAttr) {
2254      NewAttr->setInherited(true);
2255      D->addAttr(NewAttr);
2256      return true;
2257    }
2258  
2259    return false;
2260  }
2261  
getDefinition(const Decl * D)2262  static const Decl *getDefinition(const Decl *D) {
2263    if (const TagDecl *TD = dyn_cast<TagDecl>(D))
2264      return TD->getDefinition();
2265    if (const VarDecl *VD = dyn_cast<VarDecl>(D)) {
2266      const VarDecl *Def = VD->getDefinition();
2267      if (Def)
2268        return Def;
2269      return VD->getActingDefinition();
2270    }
2271    if (const FunctionDecl *FD = dyn_cast<FunctionDecl>(D)) {
2272      const FunctionDecl* Def;
2273      if (FD->isDefined(Def))
2274        return Def;
2275    }
2276    return nullptr;
2277  }
2278  
hasAttribute(const Decl * D,attr::Kind Kind)2279  static bool hasAttribute(const Decl *D, attr::Kind Kind) {
2280    for (const auto *Attribute : D->attrs())
2281      if (Attribute->getKind() == Kind)
2282        return true;
2283    return false;
2284  }
2285  
2286  /// checkNewAttributesAfterDef - If we already have a definition, check that
2287  /// there are no new attributes in this declaration.
checkNewAttributesAfterDef(Sema & S,Decl * New,const Decl * Old)2288  static void checkNewAttributesAfterDef(Sema &S, Decl *New, const Decl *Old) {
2289    if (!New->hasAttrs())
2290      return;
2291  
2292    const Decl *Def = getDefinition(Old);
2293    if (!Def || Def == New)
2294      return;
2295  
2296    AttrVec &NewAttributes = New->getAttrs();
2297    for (unsigned I = 0, E = NewAttributes.size(); I != E;) {
2298      const Attr *NewAttribute = NewAttributes[I];
2299  
2300      if (isa<AliasAttr>(NewAttribute)) {
2301        if (FunctionDecl *FD = dyn_cast<FunctionDecl>(New)) {
2302          Sema::SkipBodyInfo SkipBody;
2303          S.CheckForFunctionRedefinition(FD, cast<FunctionDecl>(Def), &SkipBody);
2304  
2305          // If we're skipping this definition, drop the "alias" attribute.
2306          if (SkipBody.ShouldSkip) {
2307            NewAttributes.erase(NewAttributes.begin() + I);
2308            --E;
2309            continue;
2310          }
2311        } else {
2312          VarDecl *VD = cast<VarDecl>(New);
2313          unsigned Diag = cast<VarDecl>(Def)->isThisDeclarationADefinition() ==
2314                                  VarDecl::TentativeDefinition
2315                              ? diag::err_alias_after_tentative
2316                              : diag::err_redefinition;
2317          S.Diag(VD->getLocation(), Diag) << VD->getDeclName();
2318          S.Diag(Def->getLocation(), diag::note_previous_definition);
2319          VD->setInvalidDecl();
2320        }
2321        ++I;
2322        continue;
2323      }
2324  
2325      if (const VarDecl *VD = dyn_cast<VarDecl>(Def)) {
2326        // Tentative definitions are only interesting for the alias check above.
2327        if (VD->isThisDeclarationADefinition() != VarDecl::Definition) {
2328          ++I;
2329          continue;
2330        }
2331      }
2332  
2333      if (hasAttribute(Def, NewAttribute->getKind())) {
2334        ++I;
2335        continue; // regular attr merging will take care of validating this.
2336      }
2337  
2338      if (isa<C11NoReturnAttr>(NewAttribute)) {
2339        // C's _Noreturn is allowed to be added to a function after it is defined.
2340        ++I;
2341        continue;
2342      } else if (const AlignedAttr *AA = dyn_cast<AlignedAttr>(NewAttribute)) {
2343        if (AA->isAlignas()) {
2344          // C++11 [dcl.align]p6:
2345          //   if any declaration of an entity has an alignment-specifier,
2346          //   every defining declaration of that entity shall specify an
2347          //   equivalent alignment.
2348          // C11 6.7.5/7:
2349          //   If the definition of an object does not have an alignment
2350          //   specifier, any other declaration of that object shall also
2351          //   have no alignment specifier.
2352          S.Diag(Def->getLocation(), diag::err_alignas_missing_on_definition)
2353            << AA;
2354          S.Diag(NewAttribute->getLocation(), diag::note_alignas_on_declaration)
2355            << AA;
2356          NewAttributes.erase(NewAttributes.begin() + I);
2357          --E;
2358          continue;
2359        }
2360      }
2361  
2362      S.Diag(NewAttribute->getLocation(),
2363             diag::warn_attribute_precede_definition);
2364      S.Diag(Def->getLocation(), diag::note_previous_definition);
2365      NewAttributes.erase(NewAttributes.begin() + I);
2366      --E;
2367    }
2368  }
2369  
2370  /// mergeDeclAttributes - Copy attributes from the Old decl to the New one.
mergeDeclAttributes(NamedDecl * New,Decl * Old,AvailabilityMergeKind AMK)2371  void Sema::mergeDeclAttributes(NamedDecl *New, Decl *Old,
2372                                 AvailabilityMergeKind AMK) {
2373    if (UsedAttr *OldAttr = Old->getMostRecentDecl()->getAttr<UsedAttr>()) {
2374      UsedAttr *NewAttr = OldAttr->clone(Context);
2375      NewAttr->setInherited(true);
2376      New->addAttr(NewAttr);
2377    }
2378  
2379    if (!Old->hasAttrs() && !New->hasAttrs())
2380      return;
2381  
2382    // Attributes declared post-definition are currently ignored.
2383    checkNewAttributesAfterDef(*this, New, Old);
2384  
2385    if (AsmLabelAttr *NewA = New->getAttr<AsmLabelAttr>()) {
2386      if (AsmLabelAttr *OldA = Old->getAttr<AsmLabelAttr>()) {
2387        if (OldA->getLabel() != NewA->getLabel()) {
2388          // This redeclaration changes __asm__ label.
2389          Diag(New->getLocation(), diag::err_different_asm_label);
2390          Diag(OldA->getLocation(), diag::note_previous_declaration);
2391        }
2392      } else if (Old->isUsed()) {
2393        // This redeclaration adds an __asm__ label to a declaration that has
2394        // already been ODR-used.
2395        Diag(New->getLocation(), diag::err_late_asm_label_name)
2396          << isa<FunctionDecl>(Old) << New->getAttr<AsmLabelAttr>()->getRange();
2397      }
2398    }
2399  
2400    if (!Old->hasAttrs())
2401      return;
2402  
2403    bool foundAny = New->hasAttrs();
2404  
2405    // Ensure that any moving of objects within the allocated map is done before
2406    // we process them.
2407    if (!foundAny) New->setAttrs(AttrVec());
2408  
2409    for (auto *I : Old->specific_attrs<InheritableAttr>()) {
2410      // Ignore deprecated/unavailable/availability attributes if requested.
2411      AvailabilityMergeKind LocalAMK = AMK_None;
2412      if (isa<DeprecatedAttr>(I) ||
2413          isa<UnavailableAttr>(I) ||
2414          isa<AvailabilityAttr>(I)) {
2415        switch (AMK) {
2416        case AMK_None:
2417          continue;
2418  
2419        case AMK_Redeclaration:
2420        case AMK_Override:
2421        case AMK_ProtocolImplementation:
2422          LocalAMK = AMK;
2423          break;
2424        }
2425      }
2426  
2427      // Already handled.
2428      if (isa<UsedAttr>(I))
2429        continue;
2430  
2431      if (mergeDeclAttribute(*this, New, I, LocalAMK))
2432        foundAny = true;
2433    }
2434  
2435    if (mergeAlignedAttrs(*this, New, Old))
2436      foundAny = true;
2437  
2438    if (!foundAny) New->dropAttrs();
2439  }
2440  
2441  /// mergeParamDeclAttributes - Copy attributes from the old parameter
2442  /// to the new one.
mergeParamDeclAttributes(ParmVarDecl * newDecl,const ParmVarDecl * oldDecl,Sema & S)2443  static void mergeParamDeclAttributes(ParmVarDecl *newDecl,
2444                                       const ParmVarDecl *oldDecl,
2445                                       Sema &S) {
2446    // C++11 [dcl.attr.depend]p2:
2447    //   The first declaration of a function shall specify the
2448    //   carries_dependency attribute for its declarator-id if any declaration
2449    //   of the function specifies the carries_dependency attribute.
2450    const CarriesDependencyAttr *CDA = newDecl->getAttr<CarriesDependencyAttr>();
2451    if (CDA && !oldDecl->hasAttr<CarriesDependencyAttr>()) {
2452      S.Diag(CDA->getLocation(),
2453             diag::err_carries_dependency_missing_on_first_decl) << 1/*Param*/;
2454      // Find the first declaration of the parameter.
2455      // FIXME: Should we build redeclaration chains for function parameters?
2456      const FunctionDecl *FirstFD =
2457        cast<FunctionDecl>(oldDecl->getDeclContext())->getFirstDecl();
2458      const ParmVarDecl *FirstVD =
2459        FirstFD->getParamDecl(oldDecl->getFunctionScopeIndex());
2460      S.Diag(FirstVD->getLocation(),
2461             diag::note_carries_dependency_missing_first_decl) << 1/*Param*/;
2462    }
2463  
2464    if (!oldDecl->hasAttrs())
2465      return;
2466  
2467    bool foundAny = newDecl->hasAttrs();
2468  
2469    // Ensure that any moving of objects within the allocated map is
2470    // done before we process them.
2471    if (!foundAny) newDecl->setAttrs(AttrVec());
2472  
2473    for (const auto *I : oldDecl->specific_attrs<InheritableParamAttr>()) {
2474      if (!DeclHasAttr(newDecl, I)) {
2475        InheritableAttr *newAttr =
2476          cast<InheritableParamAttr>(I->clone(S.Context));
2477        newAttr->setInherited(true);
2478        newDecl->addAttr(newAttr);
2479        foundAny = true;
2480      }
2481    }
2482  
2483    if (!foundAny) newDecl->dropAttrs();
2484  }
2485  
mergeParamDeclTypes(ParmVarDecl * NewParam,const ParmVarDecl * OldParam,Sema & S)2486  static void mergeParamDeclTypes(ParmVarDecl *NewParam,
2487                                  const ParmVarDecl *OldParam,
2488                                  Sema &S) {
2489    if (auto Oldnullability = OldParam->getType()->getNullability(S.Context)) {
2490      if (auto Newnullability = NewParam->getType()->getNullability(S.Context)) {
2491        if (*Oldnullability != *Newnullability) {
2492          S.Diag(NewParam->getLocation(), diag::warn_mismatched_nullability_attr)
2493            << DiagNullabilityKind(
2494                 *Newnullability,
2495                 ((NewParam->getObjCDeclQualifier() & Decl::OBJC_TQ_CSNullability)
2496                  != 0))
2497            << DiagNullabilityKind(
2498                 *Oldnullability,
2499                 ((OldParam->getObjCDeclQualifier() & Decl::OBJC_TQ_CSNullability)
2500                  != 0));
2501          S.Diag(OldParam->getLocation(), diag::note_previous_declaration);
2502        }
2503      } else {
2504        QualType NewT = NewParam->getType();
2505        NewT = S.Context.getAttributedType(
2506                           AttributedType::getNullabilityAttrKind(*Oldnullability),
2507                           NewT, NewT);
2508        NewParam->setType(NewT);
2509      }
2510    }
2511  }
2512  
2513  namespace {
2514  
2515  /// Used in MergeFunctionDecl to keep track of function parameters in
2516  /// C.
2517  struct GNUCompatibleParamWarning {
2518    ParmVarDecl *OldParm;
2519    ParmVarDecl *NewParm;
2520    QualType PromotedType;
2521  };
2522  
2523  }
2524  
2525  /// getSpecialMember - get the special member enum for a method.
getSpecialMember(const CXXMethodDecl * MD)2526  Sema::CXXSpecialMember Sema::getSpecialMember(const CXXMethodDecl *MD) {
2527    if (const CXXConstructorDecl *Ctor = dyn_cast<CXXConstructorDecl>(MD)) {
2528      if (Ctor->isDefaultConstructor())
2529        return Sema::CXXDefaultConstructor;
2530  
2531      if (Ctor->isCopyConstructor())
2532        return Sema::CXXCopyConstructor;
2533  
2534      if (Ctor->isMoveConstructor())
2535        return Sema::CXXMoveConstructor;
2536    } else if (isa<CXXDestructorDecl>(MD)) {
2537      return Sema::CXXDestructor;
2538    } else if (MD->isCopyAssignmentOperator()) {
2539      return Sema::CXXCopyAssignment;
2540    } else if (MD->isMoveAssignmentOperator()) {
2541      return Sema::CXXMoveAssignment;
2542    }
2543  
2544    return Sema::CXXInvalid;
2545  }
2546  
2547  // Determine whether the previous declaration was a definition, implicit
2548  // declaration, or a declaration.
2549  template <typename T>
2550  static std::pair<diag::kind, SourceLocation>
getNoteDiagForInvalidRedeclaration(const T * Old,const T * New)2551  getNoteDiagForInvalidRedeclaration(const T *Old, const T *New) {
2552    diag::kind PrevDiag;
2553    SourceLocation OldLocation = Old->getLocation();
2554    if (Old->isThisDeclarationADefinition())
2555      PrevDiag = diag::note_previous_definition;
2556    else if (Old->isImplicit()) {
2557      PrevDiag = diag::note_previous_implicit_declaration;
2558      if (OldLocation.isInvalid())
2559        OldLocation = New->getLocation();
2560    } else
2561      PrevDiag = diag::note_previous_declaration;
2562    return std::make_pair(PrevDiag, OldLocation);
2563  }
2564  
2565  /// canRedefineFunction - checks if a function can be redefined. Currently,
2566  /// only extern inline functions can be redefined, and even then only in
2567  /// GNU89 mode.
canRedefineFunction(const FunctionDecl * FD,const LangOptions & LangOpts)2568  static bool canRedefineFunction(const FunctionDecl *FD,
2569                                  const LangOptions& LangOpts) {
2570    return ((FD->hasAttr<GNUInlineAttr>() || LangOpts.GNUInline) &&
2571            !LangOpts.CPlusPlus &&
2572            FD->isInlineSpecified() &&
2573            FD->getStorageClass() == SC_Extern);
2574  }
2575  
getCallingConvAttributedType(QualType T) const2576  const AttributedType *Sema::getCallingConvAttributedType(QualType T) const {
2577    const AttributedType *AT = T->getAs<AttributedType>();
2578    while (AT && !AT->isCallingConv())
2579      AT = AT->getModifiedType()->getAs<AttributedType>();
2580    return AT;
2581  }
2582  
2583  template <typename T>
haveIncompatibleLanguageLinkages(const T * Old,const T * New)2584  static bool haveIncompatibleLanguageLinkages(const T *Old, const T *New) {
2585    const DeclContext *DC = Old->getDeclContext();
2586    if (DC->isRecord())
2587      return false;
2588  
2589    LanguageLinkage OldLinkage = Old->getLanguageLinkage();
2590    if (OldLinkage == CXXLanguageLinkage && New->isInExternCContext())
2591      return true;
2592    if (OldLinkage == CLanguageLinkage && New->isInExternCXXContext())
2593      return true;
2594    return false;
2595  }
2596  
isExternC(T * D)2597  template<typename T> static bool isExternC(T *D) { return D->isExternC(); }
isExternC(VarTemplateDecl *)2598  static bool isExternC(VarTemplateDecl *) { return false; }
2599  
2600  /// \brief Check whether a redeclaration of an entity introduced by a
2601  /// using-declaration is valid, given that we know it's not an overload
2602  /// (nor a hidden tag declaration).
2603  template<typename ExpectedDecl>
checkUsingShadowRedecl(Sema & S,UsingShadowDecl * OldS,ExpectedDecl * New)2604  static bool checkUsingShadowRedecl(Sema &S, UsingShadowDecl *OldS,
2605                                     ExpectedDecl *New) {
2606    // C++11 [basic.scope.declarative]p4:
2607    //   Given a set of declarations in a single declarative region, each of
2608    //   which specifies the same unqualified name,
2609    //   -- they shall all refer to the same entity, or all refer to functions
2610    //      and function templates; or
2611    //   -- exactly one declaration shall declare a class name or enumeration
2612    //      name that is not a typedef name and the other declarations shall all
2613    //      refer to the same variable or enumerator, or all refer to functions
2614    //      and function templates; in this case the class name or enumeration
2615    //      name is hidden (3.3.10).
2616  
2617    // C++11 [namespace.udecl]p14:
2618    //   If a function declaration in namespace scope or block scope has the
2619    //   same name and the same parameter-type-list as a function introduced
2620    //   by a using-declaration, and the declarations do not declare the same
2621    //   function, the program is ill-formed.
2622  
2623    auto *Old = dyn_cast<ExpectedDecl>(OldS->getTargetDecl());
2624    if (Old &&
2625        !Old->getDeclContext()->getRedeclContext()->Equals(
2626            New->getDeclContext()->getRedeclContext()) &&
2627        !(isExternC(Old) && isExternC(New)))
2628      Old = nullptr;
2629  
2630    if (!Old) {
2631      S.Diag(New->getLocation(), diag::err_using_decl_conflict_reverse);
2632      S.Diag(OldS->getTargetDecl()->getLocation(), diag::note_using_decl_target);
2633      S.Diag(OldS->getUsingDecl()->getLocation(), diag::note_using_decl) << 0;
2634      return true;
2635    }
2636    return false;
2637  }
2638  
hasIdenticalPassObjectSizeAttrs(const FunctionDecl * A,const FunctionDecl * B)2639  static bool hasIdenticalPassObjectSizeAttrs(const FunctionDecl *A,
2640                                              const FunctionDecl *B) {
2641    assert(A->getNumParams() == B->getNumParams());
2642  
2643    auto AttrEq = [](const ParmVarDecl *A, const ParmVarDecl *B) {
2644      const auto *AttrA = A->getAttr<PassObjectSizeAttr>();
2645      const auto *AttrB = B->getAttr<PassObjectSizeAttr>();
2646      if (AttrA == AttrB)
2647        return true;
2648      return AttrA && AttrB && AttrA->getType() == AttrB->getType();
2649    };
2650  
2651    return std::equal(A->param_begin(), A->param_end(), B->param_begin(), AttrEq);
2652  }
2653  
2654  /// MergeFunctionDecl - We just parsed a function 'New' from
2655  /// declarator D which has the same name and scope as a previous
2656  /// declaration 'Old'.  Figure out how to resolve this situation,
2657  /// merging decls or emitting diagnostics as appropriate.
2658  ///
2659  /// In C++, New and Old must be declarations that are not
2660  /// overloaded. Use IsOverload to determine whether New and Old are
2661  /// overloaded, and to select the Old declaration that New should be
2662  /// merged with.
2663  ///
2664  /// Returns true if there was an error, false otherwise.
MergeFunctionDecl(FunctionDecl * New,NamedDecl * & OldD,Scope * S,bool MergeTypeWithOld)2665  bool Sema::MergeFunctionDecl(FunctionDecl *New, NamedDecl *&OldD,
2666                               Scope *S, bool MergeTypeWithOld) {
2667    // Verify the old decl was also a function.
2668    FunctionDecl *Old = OldD->getAsFunction();
2669    if (!Old) {
2670      if (UsingShadowDecl *Shadow = dyn_cast<UsingShadowDecl>(OldD)) {
2671        if (New->getFriendObjectKind()) {
2672          Diag(New->getLocation(), diag::err_using_decl_friend);
2673          Diag(Shadow->getTargetDecl()->getLocation(),
2674               diag::note_using_decl_target);
2675          Diag(Shadow->getUsingDecl()->getLocation(),
2676               diag::note_using_decl) << 0;
2677          return true;
2678        }
2679  
2680        // Check whether the two declarations might declare the same function.
2681        if (checkUsingShadowRedecl<FunctionDecl>(*this, Shadow, New))
2682          return true;
2683        OldD = Old = cast<FunctionDecl>(Shadow->getTargetDecl());
2684      } else {
2685        Diag(New->getLocation(), diag::err_redefinition_different_kind)
2686          << New->getDeclName();
2687        Diag(OldD->getLocation(), diag::note_previous_definition);
2688        return true;
2689      }
2690    }
2691  
2692    // If the old declaration is invalid, just give up here.
2693    if (Old->isInvalidDecl())
2694      return true;
2695  
2696    diag::kind PrevDiag;
2697    SourceLocation OldLocation;
2698    std::tie(PrevDiag, OldLocation) =
2699        getNoteDiagForInvalidRedeclaration(Old, New);
2700  
2701    // Don't complain about this if we're in GNU89 mode and the old function
2702    // is an extern inline function.
2703    // Don't complain about specializations. They are not supposed to have
2704    // storage classes.
2705    if (!isa<CXXMethodDecl>(New) && !isa<CXXMethodDecl>(Old) &&
2706        New->getStorageClass() == SC_Static &&
2707        Old->hasExternalFormalLinkage() &&
2708        !New->getTemplateSpecializationInfo() &&
2709        !canRedefineFunction(Old, getLangOpts())) {
2710      if (getLangOpts().MicrosoftExt) {
2711        Diag(New->getLocation(), diag::ext_static_non_static) << New;
2712        Diag(OldLocation, PrevDiag);
2713      } else {
2714        Diag(New->getLocation(), diag::err_static_non_static) << New;
2715        Diag(OldLocation, PrevDiag);
2716        return true;
2717      }
2718    }
2719  
2720    if (New->hasAttr<InternalLinkageAttr>() &&
2721        !Old->hasAttr<InternalLinkageAttr>()) {
2722      Diag(New->getLocation(), diag::err_internal_linkage_redeclaration)
2723          << New->getDeclName();
2724      Diag(Old->getLocation(), diag::note_previous_definition);
2725      New->dropAttr<InternalLinkageAttr>();
2726    }
2727  
2728    // If a function is first declared with a calling convention, but is later
2729    // declared or defined without one, all following decls assume the calling
2730    // convention of the first.
2731    //
2732    // It's OK if a function is first declared without a calling convention,
2733    // but is later declared or defined with the default calling convention.
2734    //
2735    // To test if either decl has an explicit calling convention, we look for
2736    // AttributedType sugar nodes on the type as written.  If they are missing or
2737    // were canonicalized away, we assume the calling convention was implicit.
2738    //
2739    // Note also that we DO NOT return at this point, because we still have
2740    // other tests to run.
2741    QualType OldQType = Context.getCanonicalType(Old->getType());
2742    QualType NewQType = Context.getCanonicalType(New->getType());
2743    const FunctionType *OldType = cast<FunctionType>(OldQType);
2744    const FunctionType *NewType = cast<FunctionType>(NewQType);
2745    FunctionType::ExtInfo OldTypeInfo = OldType->getExtInfo();
2746    FunctionType::ExtInfo NewTypeInfo = NewType->getExtInfo();
2747    bool RequiresAdjustment = false;
2748  
2749    if (OldTypeInfo.getCC() != NewTypeInfo.getCC()) {
2750      FunctionDecl *First = Old->getFirstDecl();
2751      const FunctionType *FT =
2752          First->getType().getCanonicalType()->castAs<FunctionType>();
2753      FunctionType::ExtInfo FI = FT->getExtInfo();
2754      bool NewCCExplicit = getCallingConvAttributedType(New->getType());
2755      if (!NewCCExplicit) {
2756        // Inherit the CC from the previous declaration if it was specified
2757        // there but not here.
2758        NewTypeInfo = NewTypeInfo.withCallingConv(OldTypeInfo.getCC());
2759        RequiresAdjustment = true;
2760      } else {
2761        // Calling conventions aren't compatible, so complain.
2762        bool FirstCCExplicit = getCallingConvAttributedType(First->getType());
2763        Diag(New->getLocation(), diag::err_cconv_change)
2764          << FunctionType::getNameForCallConv(NewTypeInfo.getCC())
2765          << !FirstCCExplicit
2766          << (!FirstCCExplicit ? "" :
2767              FunctionType::getNameForCallConv(FI.getCC()));
2768  
2769        // Put the note on the first decl, since it is the one that matters.
2770        Diag(First->getLocation(), diag::note_previous_declaration);
2771        return true;
2772      }
2773    }
2774  
2775    // FIXME: diagnose the other way around?
2776    if (OldTypeInfo.getNoReturn() && !NewTypeInfo.getNoReturn()) {
2777      NewTypeInfo = NewTypeInfo.withNoReturn(true);
2778      RequiresAdjustment = true;
2779    }
2780  
2781    // Merge regparm attribute.
2782    if (OldTypeInfo.getHasRegParm() != NewTypeInfo.getHasRegParm() ||
2783        OldTypeInfo.getRegParm() != NewTypeInfo.getRegParm()) {
2784      if (NewTypeInfo.getHasRegParm()) {
2785        Diag(New->getLocation(), diag::err_regparm_mismatch)
2786          << NewType->getRegParmType()
2787          << OldType->getRegParmType();
2788        Diag(OldLocation, diag::note_previous_declaration);
2789        return true;
2790      }
2791  
2792      NewTypeInfo = NewTypeInfo.withRegParm(OldTypeInfo.getRegParm());
2793      RequiresAdjustment = true;
2794    }
2795  
2796    // Merge ns_returns_retained attribute.
2797    if (OldTypeInfo.getProducesResult() != NewTypeInfo.getProducesResult()) {
2798      if (NewTypeInfo.getProducesResult()) {
2799        Diag(New->getLocation(), diag::err_returns_retained_mismatch);
2800        Diag(OldLocation, diag::note_previous_declaration);
2801        return true;
2802      }
2803  
2804      NewTypeInfo = NewTypeInfo.withProducesResult(true);
2805      RequiresAdjustment = true;
2806    }
2807  
2808    if (RequiresAdjustment) {
2809      const FunctionType *AdjustedType = New->getType()->getAs<FunctionType>();
2810      AdjustedType = Context.adjustFunctionType(AdjustedType, NewTypeInfo);
2811      New->setType(QualType(AdjustedType, 0));
2812      NewQType = Context.getCanonicalType(New->getType());
2813      NewType = cast<FunctionType>(NewQType);
2814    }
2815  
2816    // If this redeclaration makes the function inline, we may need to add it to
2817    // UndefinedButUsed.
2818    if (!Old->isInlined() && New->isInlined() &&
2819        !New->hasAttr<GNUInlineAttr>() &&
2820        !getLangOpts().GNUInline &&
2821        Old->isUsed(false) &&
2822        !Old->isDefined() && !New->isThisDeclarationADefinition())
2823      UndefinedButUsed.insert(std::make_pair(Old->getCanonicalDecl(),
2824                                             SourceLocation()));
2825  
2826    // If this redeclaration makes it newly gnu_inline, we don't want to warn
2827    // about it.
2828    if (New->hasAttr<GNUInlineAttr>() &&
2829        Old->isInlined() && !Old->hasAttr<GNUInlineAttr>()) {
2830      UndefinedButUsed.erase(Old->getCanonicalDecl());
2831    }
2832  
2833    // If pass_object_size params don't match up perfectly, this isn't a valid
2834    // redeclaration.
2835    if (Old->getNumParams() > 0 && Old->getNumParams() == New->getNumParams() &&
2836        !hasIdenticalPassObjectSizeAttrs(Old, New)) {
2837      Diag(New->getLocation(), diag::err_different_pass_object_size_params)
2838          << New->getDeclName();
2839      Diag(OldLocation, PrevDiag) << Old << Old->getType();
2840      return true;
2841    }
2842  
2843    if (getLangOpts().CPlusPlus) {
2844      // (C++98 13.1p2):
2845      //   Certain function declarations cannot be overloaded:
2846      //     -- Function declarations that differ only in the return type
2847      //        cannot be overloaded.
2848  
2849      // Go back to the type source info to compare the declared return types,
2850      // per C++1y [dcl.type.auto]p13:
2851      //   Redeclarations or specializations of a function or function template
2852      //   with a declared return type that uses a placeholder type shall also
2853      //   use that placeholder, not a deduced type.
2854      QualType OldDeclaredReturnType =
2855          (Old->getTypeSourceInfo()
2856               ? Old->getTypeSourceInfo()->getType()->castAs<FunctionType>()
2857               : OldType)->getReturnType();
2858      QualType NewDeclaredReturnType =
2859          (New->getTypeSourceInfo()
2860               ? New->getTypeSourceInfo()->getType()->castAs<FunctionType>()
2861               : NewType)->getReturnType();
2862      QualType ResQT;
2863      if (!Context.hasSameType(OldDeclaredReturnType, NewDeclaredReturnType) &&
2864          !((NewQType->isDependentType() || OldQType->isDependentType()) &&
2865            New->isLocalExternDecl())) {
2866        if (NewDeclaredReturnType->isObjCObjectPointerType() &&
2867            OldDeclaredReturnType->isObjCObjectPointerType())
2868          ResQT = Context.mergeObjCGCQualifiers(NewQType, OldQType);
2869        if (ResQT.isNull()) {
2870          if (New->isCXXClassMember() && New->isOutOfLine())
2871            Diag(New->getLocation(), diag::err_member_def_does_not_match_ret_type)
2872                << New << New->getReturnTypeSourceRange();
2873          else
2874            Diag(New->getLocation(), diag::err_ovl_diff_return_type)
2875                << New->getReturnTypeSourceRange();
2876          Diag(OldLocation, PrevDiag) << Old << Old->getType()
2877                                      << Old->getReturnTypeSourceRange();
2878          return true;
2879        }
2880        else
2881          NewQType = ResQT;
2882      }
2883  
2884      QualType OldReturnType = OldType->getReturnType();
2885      QualType NewReturnType = cast<FunctionType>(NewQType)->getReturnType();
2886      if (OldReturnType != NewReturnType) {
2887        // If this function has a deduced return type and has already been
2888        // defined, copy the deduced value from the old declaration.
2889        AutoType *OldAT = Old->getReturnType()->getContainedAutoType();
2890        if (OldAT && OldAT->isDeduced()) {
2891          New->setType(
2892              SubstAutoType(New->getType(),
2893                            OldAT->isDependentType() ? Context.DependentTy
2894                                                     : OldAT->getDeducedType()));
2895          NewQType = Context.getCanonicalType(
2896              SubstAutoType(NewQType,
2897                            OldAT->isDependentType() ? Context.DependentTy
2898                                                     : OldAT->getDeducedType()));
2899        }
2900      }
2901  
2902      const CXXMethodDecl *OldMethod = dyn_cast<CXXMethodDecl>(Old);
2903      CXXMethodDecl *NewMethod = dyn_cast<CXXMethodDecl>(New);
2904      if (OldMethod && NewMethod) {
2905        // Preserve triviality.
2906        NewMethod->setTrivial(OldMethod->isTrivial());
2907  
2908        // MSVC allows explicit template specialization at class scope:
2909        // 2 CXXMethodDecls referring to the same function will be injected.
2910        // We don't want a redeclaration error.
2911        bool IsClassScopeExplicitSpecialization =
2912                                OldMethod->isFunctionTemplateSpecialization() &&
2913                                NewMethod->isFunctionTemplateSpecialization();
2914        bool isFriend = NewMethod->getFriendObjectKind();
2915  
2916        if (!isFriend && NewMethod->getLexicalDeclContext()->isRecord() &&
2917            !IsClassScopeExplicitSpecialization) {
2918          //    -- Member function declarations with the same name and the
2919          //       same parameter types cannot be overloaded if any of them
2920          //       is a static member function declaration.
2921          if (OldMethod->isStatic() != NewMethod->isStatic()) {
2922            Diag(New->getLocation(), diag::err_ovl_static_nonstatic_member);
2923            Diag(OldLocation, PrevDiag) << Old << Old->getType();
2924            return true;
2925          }
2926  
2927          // C++ [class.mem]p1:
2928          //   [...] A member shall not be declared twice in the
2929          //   member-specification, except that a nested class or member
2930          //   class template can be declared and then later defined.
2931          if (ActiveTemplateInstantiations.empty()) {
2932            unsigned NewDiag;
2933            if (isa<CXXConstructorDecl>(OldMethod))
2934              NewDiag = diag::err_constructor_redeclared;
2935            else if (isa<CXXDestructorDecl>(NewMethod))
2936              NewDiag = diag::err_destructor_redeclared;
2937            else if (isa<CXXConversionDecl>(NewMethod))
2938              NewDiag = diag::err_conv_function_redeclared;
2939            else
2940              NewDiag = diag::err_member_redeclared;
2941  
2942            Diag(New->getLocation(), NewDiag);
2943          } else {
2944            Diag(New->getLocation(), diag::err_member_redeclared_in_instantiation)
2945              << New << New->getType();
2946          }
2947          Diag(OldLocation, PrevDiag) << Old << Old->getType();
2948          return true;
2949  
2950        // Complain if this is an explicit declaration of a special
2951        // member that was initially declared implicitly.
2952        //
2953        // As an exception, it's okay to befriend such methods in order
2954        // to permit the implicit constructor/destructor/operator calls.
2955        } else if (OldMethod->isImplicit()) {
2956          if (isFriend) {
2957            NewMethod->setImplicit();
2958          } else {
2959            Diag(NewMethod->getLocation(),
2960                 diag::err_definition_of_implicitly_declared_member)
2961              << New << getSpecialMember(OldMethod);
2962            return true;
2963          }
2964        } else if (OldMethod->isExplicitlyDefaulted() && !isFriend) {
2965          Diag(NewMethod->getLocation(),
2966               diag::err_definition_of_explicitly_defaulted_member)
2967            << getSpecialMember(OldMethod);
2968          return true;
2969        }
2970      }
2971  
2972      // C++11 [dcl.attr.noreturn]p1:
2973      //   The first declaration of a function shall specify the noreturn
2974      //   attribute if any declaration of that function specifies the noreturn
2975      //   attribute.
2976      const CXX11NoReturnAttr *NRA = New->getAttr<CXX11NoReturnAttr>();
2977      if (NRA && !Old->hasAttr<CXX11NoReturnAttr>()) {
2978        Diag(NRA->getLocation(), diag::err_noreturn_missing_on_first_decl);
2979        Diag(Old->getFirstDecl()->getLocation(),
2980             diag::note_noreturn_missing_first_decl);
2981      }
2982  
2983      // C++11 [dcl.attr.depend]p2:
2984      //   The first declaration of a function shall specify the
2985      //   carries_dependency attribute for its declarator-id if any declaration
2986      //   of the function specifies the carries_dependency attribute.
2987      const CarriesDependencyAttr *CDA = New->getAttr<CarriesDependencyAttr>();
2988      if (CDA && !Old->hasAttr<CarriesDependencyAttr>()) {
2989        Diag(CDA->getLocation(),
2990             diag::err_carries_dependency_missing_on_first_decl) << 0/*Function*/;
2991        Diag(Old->getFirstDecl()->getLocation(),
2992             diag::note_carries_dependency_missing_first_decl) << 0/*Function*/;
2993      }
2994  
2995      // (C++98 8.3.5p3):
2996      //   All declarations for a function shall agree exactly in both the
2997      //   return type and the parameter-type-list.
2998      // We also want to respect all the extended bits except noreturn.
2999  
3000      // noreturn should now match unless the old type info didn't have it.
3001      QualType OldQTypeForComparison = OldQType;
3002      if (!OldTypeInfo.getNoReturn() && NewTypeInfo.getNoReturn()) {
3003        assert(OldQType == QualType(OldType, 0));
3004        const FunctionType *OldTypeForComparison
3005          = Context.adjustFunctionType(OldType, OldTypeInfo.withNoReturn(true));
3006        OldQTypeForComparison = QualType(OldTypeForComparison, 0);
3007        assert(OldQTypeForComparison.isCanonical());
3008      }
3009  
3010      if (haveIncompatibleLanguageLinkages(Old, New)) {
3011        // As a special case, retain the language linkage from previous
3012        // declarations of a friend function as an extension.
3013        //
3014        // This liberal interpretation of C++ [class.friend]p3 matches GCC/MSVC
3015        // and is useful because there's otherwise no way to specify language
3016        // linkage within class scope.
3017        //
3018        // Check cautiously as the friend object kind isn't yet complete.
3019        if (New->getFriendObjectKind() != Decl::FOK_None) {
3020          Diag(New->getLocation(), diag::ext_retained_language_linkage) << New;
3021          Diag(OldLocation, PrevDiag);
3022        } else {
3023          Diag(New->getLocation(), diag::err_different_language_linkage) << New;
3024          Diag(OldLocation, PrevDiag);
3025          return true;
3026        }
3027      }
3028  
3029      if (OldQTypeForComparison == NewQType)
3030        return MergeCompatibleFunctionDecls(New, Old, S, MergeTypeWithOld);
3031  
3032      if ((NewQType->isDependentType() || OldQType->isDependentType()) &&
3033          New->isLocalExternDecl()) {
3034        // It's OK if we couldn't merge types for a local function declaraton
3035        // if either the old or new type is dependent. We'll merge the types
3036        // when we instantiate the function.
3037        return false;
3038      }
3039  
3040      // Fall through for conflicting redeclarations and redefinitions.
3041    }
3042  
3043    // C: Function types need to be compatible, not identical. This handles
3044    // duplicate function decls like "void f(int); void f(enum X);" properly.
3045    if (!getLangOpts().CPlusPlus &&
3046        Context.typesAreCompatible(OldQType, NewQType)) {
3047      const FunctionType *OldFuncType = OldQType->getAs<FunctionType>();
3048      const FunctionType *NewFuncType = NewQType->getAs<FunctionType>();
3049      const FunctionProtoType *OldProto = nullptr;
3050      if (MergeTypeWithOld && isa<FunctionNoProtoType>(NewFuncType) &&
3051          (OldProto = dyn_cast<FunctionProtoType>(OldFuncType))) {
3052        // The old declaration provided a function prototype, but the
3053        // new declaration does not. Merge in the prototype.
3054        assert(!OldProto->hasExceptionSpec() && "Exception spec in C");
3055        SmallVector<QualType, 16> ParamTypes(OldProto->param_types());
3056        NewQType =
3057            Context.getFunctionType(NewFuncType->getReturnType(), ParamTypes,
3058                                    OldProto->getExtProtoInfo());
3059        New->setType(NewQType);
3060        New->setHasInheritedPrototype();
3061  
3062        // Synthesize parameters with the same types.
3063        SmallVector<ParmVarDecl*, 16> Params;
3064        for (const auto &ParamType : OldProto->param_types()) {
3065          ParmVarDecl *Param = ParmVarDecl::Create(Context, New, SourceLocation(),
3066                                                   SourceLocation(), nullptr,
3067                                                   ParamType, /*TInfo=*/nullptr,
3068                                                   SC_None, nullptr);
3069          Param->setScopeInfo(0, Params.size());
3070          Param->setImplicit();
3071          Params.push_back(Param);
3072        }
3073  
3074        New->setParams(Params);
3075      }
3076  
3077      return MergeCompatibleFunctionDecls(New, Old, S, MergeTypeWithOld);
3078    }
3079  
3080    // GNU C permits a K&R definition to follow a prototype declaration
3081    // if the declared types of the parameters in the K&R definition
3082    // match the types in the prototype declaration, even when the
3083    // promoted types of the parameters from the K&R definition differ
3084    // from the types in the prototype. GCC then keeps the types from
3085    // the prototype.
3086    //
3087    // If a variadic prototype is followed by a non-variadic K&R definition,
3088    // the K&R definition becomes variadic.  This is sort of an edge case, but
3089    // it's legal per the standard depending on how you read C99 6.7.5.3p15 and
3090    // C99 6.9.1p8.
3091    if (!getLangOpts().CPlusPlus &&
3092        Old->hasPrototype() && !New->hasPrototype() &&
3093        New->getType()->getAs<FunctionProtoType>() &&
3094        Old->getNumParams() == New->getNumParams()) {
3095      SmallVector<QualType, 16> ArgTypes;
3096      SmallVector<GNUCompatibleParamWarning, 16> Warnings;
3097      const FunctionProtoType *OldProto
3098        = Old->getType()->getAs<FunctionProtoType>();
3099      const FunctionProtoType *NewProto
3100        = New->getType()->getAs<FunctionProtoType>();
3101  
3102      // Determine whether this is the GNU C extension.
3103      QualType MergedReturn = Context.mergeTypes(OldProto->getReturnType(),
3104                                                 NewProto->getReturnType());
3105      bool LooseCompatible = !MergedReturn.isNull();
3106      for (unsigned Idx = 0, End = Old->getNumParams();
3107           LooseCompatible && Idx != End; ++Idx) {
3108        ParmVarDecl *OldParm = Old->getParamDecl(Idx);
3109        ParmVarDecl *NewParm = New->getParamDecl(Idx);
3110        if (Context.typesAreCompatible(OldParm->getType(),
3111                                       NewProto->getParamType(Idx))) {
3112          ArgTypes.push_back(NewParm->getType());
3113        } else if (Context.typesAreCompatible(OldParm->getType(),
3114                                              NewParm->getType(),
3115                                              /*CompareUnqualified=*/true)) {
3116          GNUCompatibleParamWarning Warn = { OldParm, NewParm,
3117                                             NewProto->getParamType(Idx) };
3118          Warnings.push_back(Warn);
3119          ArgTypes.push_back(NewParm->getType());
3120        } else
3121          LooseCompatible = false;
3122      }
3123  
3124      if (LooseCompatible) {
3125        for (unsigned Warn = 0; Warn < Warnings.size(); ++Warn) {
3126          Diag(Warnings[Warn].NewParm->getLocation(),
3127               diag::ext_param_promoted_not_compatible_with_prototype)
3128            << Warnings[Warn].PromotedType
3129            << Warnings[Warn].OldParm->getType();
3130          if (Warnings[Warn].OldParm->getLocation().isValid())
3131            Diag(Warnings[Warn].OldParm->getLocation(),
3132                 diag::note_previous_declaration);
3133        }
3134  
3135        if (MergeTypeWithOld)
3136          New->setType(Context.getFunctionType(MergedReturn, ArgTypes,
3137                                               OldProto->getExtProtoInfo()));
3138        return MergeCompatibleFunctionDecls(New, Old, S, MergeTypeWithOld);
3139      }
3140  
3141      // Fall through to diagnose conflicting types.
3142    }
3143  
3144    // A function that has already been declared has been redeclared or
3145    // defined with a different type; show an appropriate diagnostic.
3146  
3147    // If the previous declaration was an implicitly-generated builtin
3148    // declaration, then at the very least we should use a specialized note.
3149    unsigned BuiltinID;
3150    if (Old->isImplicit() && (BuiltinID = Old->getBuiltinID())) {
3151      // If it's actually a library-defined builtin function like 'malloc'
3152      // or 'printf', just warn about the incompatible redeclaration.
3153      if (Context.BuiltinInfo.isPredefinedLibFunction(BuiltinID)) {
3154        Diag(New->getLocation(), diag::warn_redecl_library_builtin) << New;
3155        Diag(OldLocation, diag::note_previous_builtin_declaration)
3156          << Old << Old->getType();
3157  
3158        // If this is a global redeclaration, just forget hereafter
3159        // about the "builtin-ness" of the function.
3160        //
3161        // Doing this for local extern declarations is problematic.  If
3162        // the builtin declaration remains visible, a second invalid
3163        // local declaration will produce a hard error; if it doesn't
3164        // remain visible, a single bogus local redeclaration (which is
3165        // actually only a warning) could break all the downstream code.
3166        if (!New->getLexicalDeclContext()->isFunctionOrMethod())
3167          New->getIdentifier()->revertBuiltin();
3168  
3169        return false;
3170      }
3171  
3172      PrevDiag = diag::note_previous_builtin_declaration;
3173    }
3174  
3175    Diag(New->getLocation(), diag::err_conflicting_types) << New->getDeclName();
3176    Diag(OldLocation, PrevDiag) << Old << Old->getType();
3177    return true;
3178  }
3179  
3180  /// \brief Completes the merge of two function declarations that are
3181  /// known to be compatible.
3182  ///
3183  /// This routine handles the merging of attributes and other
3184  /// properties of function declarations from the old declaration to
3185  /// the new declaration, once we know that New is in fact a
3186  /// redeclaration of Old.
3187  ///
3188  /// \returns false
MergeCompatibleFunctionDecls(FunctionDecl * New,FunctionDecl * Old,Scope * S,bool MergeTypeWithOld)3189  bool Sema::MergeCompatibleFunctionDecls(FunctionDecl *New, FunctionDecl *Old,
3190                                          Scope *S, bool MergeTypeWithOld) {
3191    // Merge the attributes
3192    mergeDeclAttributes(New, Old);
3193  
3194    // Merge "pure" flag.
3195    if (Old->isPure())
3196      New->setPure();
3197  
3198    // Merge "used" flag.
3199    if (Old->getMostRecentDecl()->isUsed(false))
3200      New->setIsUsed();
3201  
3202    // Merge attributes from the parameters.  These can mismatch with K&R
3203    // declarations.
3204    if (New->getNumParams() == Old->getNumParams())
3205        for (unsigned i = 0, e = New->getNumParams(); i != e; ++i) {
3206          ParmVarDecl *NewParam = New->getParamDecl(i);
3207          ParmVarDecl *OldParam = Old->getParamDecl(i);
3208          mergeParamDeclAttributes(NewParam, OldParam, *this);
3209          mergeParamDeclTypes(NewParam, OldParam, *this);
3210        }
3211  
3212    if (getLangOpts().CPlusPlus)
3213      return MergeCXXFunctionDecl(New, Old, S);
3214  
3215    // Merge the function types so the we get the composite types for the return
3216    // and argument types. Per C11 6.2.7/4, only update the type if the old decl
3217    // was visible.
3218    QualType Merged = Context.mergeTypes(Old->getType(), New->getType());
3219    if (!Merged.isNull() && MergeTypeWithOld)
3220      New->setType(Merged);
3221  
3222    return false;
3223  }
3224  
3225  
mergeObjCMethodDecls(ObjCMethodDecl * newMethod,ObjCMethodDecl * oldMethod)3226  void Sema::mergeObjCMethodDecls(ObjCMethodDecl *newMethod,
3227                                  ObjCMethodDecl *oldMethod) {
3228  
3229    // Merge the attributes, including deprecated/unavailable
3230    AvailabilityMergeKind MergeKind =
3231      isa<ObjCProtocolDecl>(oldMethod->getDeclContext())
3232        ? AMK_ProtocolImplementation
3233        : isa<ObjCImplDecl>(newMethod->getDeclContext()) ? AMK_Redeclaration
3234                                                         : AMK_Override;
3235  
3236    mergeDeclAttributes(newMethod, oldMethod, MergeKind);
3237  
3238    // Merge attributes from the parameters.
3239    ObjCMethodDecl::param_const_iterator oi = oldMethod->param_begin(),
3240                                         oe = oldMethod->param_end();
3241    for (ObjCMethodDecl::param_iterator
3242           ni = newMethod->param_begin(), ne = newMethod->param_end();
3243         ni != ne && oi != oe; ++ni, ++oi)
3244      mergeParamDeclAttributes(*ni, *oi, *this);
3245  
3246    CheckObjCMethodOverride(newMethod, oldMethod);
3247  }
3248  
3249  /// MergeVarDeclTypes - We parsed a variable 'New' which has the same name and
3250  /// scope as a previous declaration 'Old'.  Figure out how to merge their types,
3251  /// emitting diagnostics as appropriate.
3252  ///
3253  /// Declarations using the auto type specifier (C++ [decl.spec.auto]) call back
3254  /// to here in AddInitializerToDecl. We can't check them before the initializer
3255  /// is attached.
MergeVarDeclTypes(VarDecl * New,VarDecl * Old,bool MergeTypeWithOld)3256  void Sema::MergeVarDeclTypes(VarDecl *New, VarDecl *Old,
3257                               bool MergeTypeWithOld) {
3258    if (New->isInvalidDecl() || Old->isInvalidDecl())
3259      return;
3260  
3261    QualType MergedT;
3262    if (getLangOpts().CPlusPlus) {
3263      if (New->getType()->isUndeducedType()) {
3264        // We don't know what the new type is until the initializer is attached.
3265        return;
3266      } else if (Context.hasSameType(New->getType(), Old->getType())) {
3267        // These could still be something that needs exception specs checked.
3268        return MergeVarDeclExceptionSpecs(New, Old);
3269      }
3270      // C++ [basic.link]p10:
3271      //   [...] the types specified by all declarations referring to a given
3272      //   object or function shall be identical, except that declarations for an
3273      //   array object can specify array types that differ by the presence or
3274      //   absence of a major array bound (8.3.4).
3275      else if (Old->getType()->isIncompleteArrayType() &&
3276               New->getType()->isArrayType()) {
3277        const ArrayType *OldArray = Context.getAsArrayType(Old->getType());
3278        const ArrayType *NewArray = Context.getAsArrayType(New->getType());
3279        if (Context.hasSameType(OldArray->getElementType(),
3280                                NewArray->getElementType()))
3281          MergedT = New->getType();
3282      } else if (Old->getType()->isArrayType() &&
3283                 New->getType()->isIncompleteArrayType()) {
3284        const ArrayType *OldArray = Context.getAsArrayType(Old->getType());
3285        const ArrayType *NewArray = Context.getAsArrayType(New->getType());
3286        if (Context.hasSameType(OldArray->getElementType(),
3287                                NewArray->getElementType()))
3288          MergedT = Old->getType();
3289      } else if (New->getType()->isObjCObjectPointerType() &&
3290                 Old->getType()->isObjCObjectPointerType()) {
3291        MergedT = Context.mergeObjCGCQualifiers(New->getType(),
3292                                                Old->getType());
3293      }
3294    } else {
3295      // C 6.2.7p2:
3296      //   All declarations that refer to the same object or function shall have
3297      //   compatible type.
3298      MergedT = Context.mergeTypes(New->getType(), Old->getType());
3299    }
3300    if (MergedT.isNull()) {
3301      // It's OK if we couldn't merge types if either type is dependent, for a
3302      // block-scope variable. In other cases (static data members of class
3303      // templates, variable templates, ...), we require the types to be
3304      // equivalent.
3305      // FIXME: The C++ standard doesn't say anything about this.
3306      if ((New->getType()->isDependentType() ||
3307           Old->getType()->isDependentType()) && New->isLocalVarDecl()) {
3308        // If the old type was dependent, we can't merge with it, so the new type
3309        // becomes dependent for now. We'll reproduce the original type when we
3310        // instantiate the TypeSourceInfo for the variable.
3311        if (!New->getType()->isDependentType() && MergeTypeWithOld)
3312          New->setType(Context.DependentTy);
3313        return;
3314      }
3315  
3316      // FIXME: Even if this merging succeeds, some other non-visible declaration
3317      // of this variable might have an incompatible type. For instance:
3318      //
3319      //   extern int arr[];
3320      //   void f() { extern int arr[2]; }
3321      //   void g() { extern int arr[3]; }
3322      //
3323      // Neither C nor C++ requires a diagnostic for this, but we should still try
3324      // to diagnose it.
3325      Diag(New->getLocation(), New->isThisDeclarationADefinition()
3326                                   ? diag::err_redefinition_different_type
3327                                   : diag::err_redeclaration_different_type)
3328          << New->getDeclName() << New->getType() << Old->getType();
3329  
3330      diag::kind PrevDiag;
3331      SourceLocation OldLocation;
3332      std::tie(PrevDiag, OldLocation) =
3333          getNoteDiagForInvalidRedeclaration(Old, New);
3334      Diag(OldLocation, PrevDiag);
3335      return New->setInvalidDecl();
3336    }
3337  
3338    // Don't actually update the type on the new declaration if the old
3339    // declaration was an extern declaration in a different scope.
3340    if (MergeTypeWithOld)
3341      New->setType(MergedT);
3342  }
3343  
mergeTypeWithPrevious(Sema & S,VarDecl * NewVD,VarDecl * OldVD,LookupResult & Previous)3344  static bool mergeTypeWithPrevious(Sema &S, VarDecl *NewVD, VarDecl *OldVD,
3345                                    LookupResult &Previous) {
3346    // C11 6.2.7p4:
3347    //   For an identifier with internal or external linkage declared
3348    //   in a scope in which a prior declaration of that identifier is
3349    //   visible, if the prior declaration specifies internal or
3350    //   external linkage, the type of the identifier at the later
3351    //   declaration becomes the composite type.
3352    //
3353    // If the variable isn't visible, we do not merge with its type.
3354    if (Previous.isShadowed())
3355      return false;
3356  
3357    if (S.getLangOpts().CPlusPlus) {
3358      // C++11 [dcl.array]p3:
3359      //   If there is a preceding declaration of the entity in the same
3360      //   scope in which the bound was specified, an omitted array bound
3361      //   is taken to be the same as in that earlier declaration.
3362      return NewVD->isPreviousDeclInSameBlockScope() ||
3363             (!OldVD->getLexicalDeclContext()->isFunctionOrMethod() &&
3364              !NewVD->getLexicalDeclContext()->isFunctionOrMethod());
3365    } else {
3366      // If the old declaration was function-local, don't merge with its
3367      // type unless we're in the same function.
3368      return !OldVD->getLexicalDeclContext()->isFunctionOrMethod() ||
3369             OldVD->getLexicalDeclContext() == NewVD->getLexicalDeclContext();
3370    }
3371  }
3372  
3373  /// MergeVarDecl - We just parsed a variable 'New' which has the same name
3374  /// and scope as a previous declaration 'Old'.  Figure out how to resolve this
3375  /// situation, merging decls or emitting diagnostics as appropriate.
3376  ///
3377  /// Tentative definition rules (C99 6.9.2p2) are checked by
3378  /// FinalizeDeclaratorGroup. Unfortunately, we can't analyze tentative
3379  /// definitions here, since the initializer hasn't been attached.
3380  ///
MergeVarDecl(VarDecl * New,LookupResult & Previous)3381  void Sema::MergeVarDecl(VarDecl *New, LookupResult &Previous) {
3382    // If the new decl is already invalid, don't do any other checking.
3383    if (New->isInvalidDecl())
3384      return;
3385  
3386    if (!shouldLinkPossiblyHiddenDecl(Previous, New))
3387      return;
3388  
3389    VarTemplateDecl *NewTemplate = New->getDescribedVarTemplate();
3390  
3391    // Verify the old decl was also a variable or variable template.
3392    VarDecl *Old = nullptr;
3393    VarTemplateDecl *OldTemplate = nullptr;
3394    if (Previous.isSingleResult()) {
3395      if (NewTemplate) {
3396        OldTemplate = dyn_cast<VarTemplateDecl>(Previous.getFoundDecl());
3397        Old = OldTemplate ? OldTemplate->getTemplatedDecl() : nullptr;
3398  
3399        if (auto *Shadow =
3400                dyn_cast<UsingShadowDecl>(Previous.getRepresentativeDecl()))
3401          if (checkUsingShadowRedecl<VarTemplateDecl>(*this, Shadow, NewTemplate))
3402            return New->setInvalidDecl();
3403      } else {
3404        Old = dyn_cast<VarDecl>(Previous.getFoundDecl());
3405  
3406        if (auto *Shadow =
3407                dyn_cast<UsingShadowDecl>(Previous.getRepresentativeDecl()))
3408          if (checkUsingShadowRedecl<VarDecl>(*this, Shadow, New))
3409            return New->setInvalidDecl();
3410      }
3411    }
3412    if (!Old) {
3413      Diag(New->getLocation(), diag::err_redefinition_different_kind)
3414        << New->getDeclName();
3415      Diag(Previous.getRepresentativeDecl()->getLocation(),
3416           diag::note_previous_definition);
3417      return New->setInvalidDecl();
3418    }
3419  
3420    // Ensure the template parameters are compatible.
3421    if (NewTemplate &&
3422        !TemplateParameterListsAreEqual(NewTemplate->getTemplateParameters(),
3423                                        OldTemplate->getTemplateParameters(),
3424                                        /*Complain=*/true, TPL_TemplateMatch))
3425      return New->setInvalidDecl();
3426  
3427    // C++ [class.mem]p1:
3428    //   A member shall not be declared twice in the member-specification [...]
3429    //
3430    // Here, we need only consider static data members.
3431    if (Old->isStaticDataMember() && !New->isOutOfLine()) {
3432      Diag(New->getLocation(), diag::err_duplicate_member)
3433        << New->getIdentifier();
3434      Diag(Old->getLocation(), diag::note_previous_declaration);
3435      New->setInvalidDecl();
3436    }
3437  
3438    mergeDeclAttributes(New, Old);
3439    // Warn if an already-declared variable is made a weak_import in a subsequent
3440    // declaration
3441    if (New->hasAttr<WeakImportAttr>() &&
3442        Old->getStorageClass() == SC_None &&
3443        !Old->hasAttr<WeakImportAttr>()) {
3444      Diag(New->getLocation(), diag::warn_weak_import) << New->getDeclName();
3445      Diag(Old->getLocation(), diag::note_previous_definition);
3446      // Remove weak_import attribute on new declaration.
3447      New->dropAttr<WeakImportAttr>();
3448    }
3449  
3450    if (New->hasAttr<InternalLinkageAttr>() &&
3451        !Old->hasAttr<InternalLinkageAttr>()) {
3452      Diag(New->getLocation(), diag::err_internal_linkage_redeclaration)
3453          << New->getDeclName();
3454      Diag(Old->getLocation(), diag::note_previous_definition);
3455      New->dropAttr<InternalLinkageAttr>();
3456    }
3457  
3458    // Merge the types.
3459    VarDecl *MostRecent = Old->getMostRecentDecl();
3460    if (MostRecent != Old) {
3461      MergeVarDeclTypes(New, MostRecent,
3462                        mergeTypeWithPrevious(*this, New, MostRecent, Previous));
3463      if (New->isInvalidDecl())
3464        return;
3465    }
3466  
3467    MergeVarDeclTypes(New, Old, mergeTypeWithPrevious(*this, New, Old, Previous));
3468    if (New->isInvalidDecl())
3469      return;
3470  
3471    diag::kind PrevDiag;
3472    SourceLocation OldLocation;
3473    std::tie(PrevDiag, OldLocation) =
3474        getNoteDiagForInvalidRedeclaration(Old, New);
3475  
3476    // [dcl.stc]p8: Check if we have a non-static decl followed by a static.
3477    if (New->getStorageClass() == SC_Static &&
3478        !New->isStaticDataMember() &&
3479        Old->hasExternalFormalLinkage()) {
3480      if (getLangOpts().MicrosoftExt) {
3481        Diag(New->getLocation(), diag::ext_static_non_static)
3482            << New->getDeclName();
3483        Diag(OldLocation, PrevDiag);
3484      } else {
3485        Diag(New->getLocation(), diag::err_static_non_static)
3486            << New->getDeclName();
3487        Diag(OldLocation, PrevDiag);
3488        return New->setInvalidDecl();
3489      }
3490    }
3491    // C99 6.2.2p4:
3492    //   For an identifier declared with the storage-class specifier
3493    //   extern in a scope in which a prior declaration of that
3494    //   identifier is visible,23) if the prior declaration specifies
3495    //   internal or external linkage, the linkage of the identifier at
3496    //   the later declaration is the same as the linkage specified at
3497    //   the prior declaration. If no prior declaration is visible, or
3498    //   if the prior declaration specifies no linkage, then the
3499    //   identifier has external linkage.
3500    if (New->hasExternalStorage() && Old->hasLinkage())
3501      /* Okay */;
3502    else if (New->getCanonicalDecl()->getStorageClass() != SC_Static &&
3503             !New->isStaticDataMember() &&
3504             Old->getCanonicalDecl()->getStorageClass() == SC_Static) {
3505      Diag(New->getLocation(), diag::err_non_static_static) << New->getDeclName();
3506      Diag(OldLocation, PrevDiag);
3507      return New->setInvalidDecl();
3508    }
3509  
3510    // Check if extern is followed by non-extern and vice-versa.
3511    if (New->hasExternalStorage() &&
3512        !Old->hasLinkage() && Old->isLocalVarDeclOrParm()) {
3513      Diag(New->getLocation(), diag::err_extern_non_extern) << New->getDeclName();
3514      Diag(OldLocation, PrevDiag);
3515      return New->setInvalidDecl();
3516    }
3517    if (Old->hasLinkage() && New->isLocalVarDeclOrParm() &&
3518        !New->hasExternalStorage()) {
3519      Diag(New->getLocation(), diag::err_non_extern_extern) << New->getDeclName();
3520      Diag(OldLocation, PrevDiag);
3521      return New->setInvalidDecl();
3522    }
3523  
3524    // Variables with external linkage are analyzed in FinalizeDeclaratorGroup.
3525  
3526    // FIXME: The test for external storage here seems wrong? We still
3527    // need to check for mismatches.
3528    if (!New->hasExternalStorage() && !New->isFileVarDecl() &&
3529        // Don't complain about out-of-line definitions of static members.
3530        !(Old->getLexicalDeclContext()->isRecord() &&
3531          !New->getLexicalDeclContext()->isRecord())) {
3532      Diag(New->getLocation(), diag::err_redefinition) << New->getDeclName();
3533      Diag(OldLocation, PrevDiag);
3534      return New->setInvalidDecl();
3535    }
3536  
3537    if (New->getTLSKind() != Old->getTLSKind()) {
3538      if (!Old->getTLSKind()) {
3539        Diag(New->getLocation(), diag::err_thread_non_thread) << New->getDeclName();
3540        Diag(OldLocation, PrevDiag);
3541      } else if (!New->getTLSKind()) {
3542        Diag(New->getLocation(), diag::err_non_thread_thread) << New->getDeclName();
3543        Diag(OldLocation, PrevDiag);
3544      } else {
3545        // Do not allow redeclaration to change the variable between requiring
3546        // static and dynamic initialization.
3547        // FIXME: GCC allows this, but uses the TLS keyword on the first
3548        // declaration to determine the kind. Do we need to be compatible here?
3549        Diag(New->getLocation(), diag::err_thread_thread_different_kind)
3550          << New->getDeclName() << (New->getTLSKind() == VarDecl::TLS_Dynamic);
3551        Diag(OldLocation, PrevDiag);
3552      }
3553    }
3554  
3555    // C++ doesn't have tentative definitions, so go right ahead and check here.
3556    VarDecl *Def;
3557    if (getLangOpts().CPlusPlus &&
3558        New->isThisDeclarationADefinition() == VarDecl::Definition &&
3559        (Def = Old->getDefinition())) {
3560      NamedDecl *Hidden = nullptr;
3561      if (!hasVisibleDefinition(Def, &Hidden) &&
3562          (New->getFormalLinkage() == InternalLinkage ||
3563           New->getDescribedVarTemplate() ||
3564           New->getNumTemplateParameterLists() ||
3565           New->getDeclContext()->isDependentContext())) {
3566        // The previous definition is hidden, and multiple definitions are
3567        // permitted (in separate TUs). Form another definition of it.
3568      } else {
3569        Diag(New->getLocation(), diag::err_redefinition) << New;
3570        Diag(Def->getLocation(), diag::note_previous_definition);
3571        New->setInvalidDecl();
3572        return;
3573      }
3574    }
3575  
3576    if (haveIncompatibleLanguageLinkages(Old, New)) {
3577      Diag(New->getLocation(), diag::err_different_language_linkage) << New;
3578      Diag(OldLocation, PrevDiag);
3579      New->setInvalidDecl();
3580      return;
3581    }
3582  
3583    // Merge "used" flag.
3584    if (Old->getMostRecentDecl()->isUsed(false))
3585      New->setIsUsed();
3586  
3587    // Keep a chain of previous declarations.
3588    New->setPreviousDecl(Old);
3589    if (NewTemplate)
3590      NewTemplate->setPreviousDecl(OldTemplate);
3591  
3592    // Inherit access appropriately.
3593    New->setAccess(Old->getAccess());
3594    if (NewTemplate)
3595      NewTemplate->setAccess(New->getAccess());
3596  }
3597  
3598  /// ParsedFreeStandingDeclSpec - This method is invoked when a declspec with
3599  /// no declarator (e.g. "struct foo;") is parsed.
ParsedFreeStandingDeclSpec(Scope * S,AccessSpecifier AS,DeclSpec & DS)3600  Decl *Sema::ParsedFreeStandingDeclSpec(Scope *S, AccessSpecifier AS,
3601                                         DeclSpec &DS) {
3602    return ParsedFreeStandingDeclSpec(S, AS, DS, MultiTemplateParamsArg());
3603  }
3604  
3605  // The MS ABI changed between VS2013 and VS2015 with regard to numbers used to
3606  // disambiguate entities defined in different scopes.
3607  // While the VS2015 ABI fixes potential miscompiles, it is also breaks
3608  // compatibility.
3609  // We will pick our mangling number depending on which version of MSVC is being
3610  // targeted.
getMSManglingNumber(const LangOptions & LO,Scope * S)3611  static unsigned getMSManglingNumber(const LangOptions &LO, Scope *S) {
3612    return LO.isCompatibleWithMSVC(LangOptions::MSVC2015)
3613               ? S->getMSCurManglingNumber()
3614               : S->getMSLastManglingNumber();
3615  }
3616  
handleTagNumbering(const TagDecl * Tag,Scope * TagScope)3617  void Sema::handleTagNumbering(const TagDecl *Tag, Scope *TagScope) {
3618    if (!Context.getLangOpts().CPlusPlus)
3619      return;
3620  
3621    if (isa<CXXRecordDecl>(Tag->getParent())) {
3622      // If this tag is the direct child of a class, number it if
3623      // it is anonymous.
3624      if (!Tag->getName().empty() || Tag->getTypedefNameForAnonDecl())
3625        return;
3626      MangleNumberingContext &MCtx =
3627          Context.getManglingNumberContext(Tag->getParent());
3628      Context.setManglingNumber(
3629          Tag, MCtx.getManglingNumber(
3630                   Tag, getMSManglingNumber(getLangOpts(), TagScope)));
3631      return;
3632    }
3633  
3634    // If this tag isn't a direct child of a class, number it if it is local.
3635    Decl *ManglingContextDecl;
3636    if (MangleNumberingContext *MCtx = getCurrentMangleNumberContext(
3637            Tag->getDeclContext(), ManglingContextDecl)) {
3638      Context.setManglingNumber(
3639          Tag, MCtx->getManglingNumber(
3640                   Tag, getMSManglingNumber(getLangOpts(), TagScope)));
3641    }
3642  }
3643  
setTagNameForLinkagePurposes(TagDecl * TagFromDeclSpec,TypedefNameDecl * NewTD)3644  void Sema::setTagNameForLinkagePurposes(TagDecl *TagFromDeclSpec,
3645                                          TypedefNameDecl *NewTD) {
3646    if (TagFromDeclSpec->isInvalidDecl())
3647      return;
3648  
3649    // Do nothing if the tag already has a name for linkage purposes.
3650    if (TagFromDeclSpec->hasNameForLinkage())
3651      return;
3652  
3653    // A well-formed anonymous tag must always be a TUK_Definition.
3654    assert(TagFromDeclSpec->isThisDeclarationADefinition());
3655  
3656    // The type must match the tag exactly;  no qualifiers allowed.
3657    if (!Context.hasSameType(NewTD->getUnderlyingType(),
3658                             Context.getTagDeclType(TagFromDeclSpec))) {
3659      if (getLangOpts().CPlusPlus)
3660        Context.addTypedefNameForUnnamedTagDecl(TagFromDeclSpec, NewTD);
3661      return;
3662    }
3663  
3664    // If we've already computed linkage for the anonymous tag, then
3665    // adding a typedef name for the anonymous decl can change that
3666    // linkage, which might be a serious problem.  Diagnose this as
3667    // unsupported and ignore the typedef name.  TODO: we should
3668    // pursue this as a language defect and establish a formal rule
3669    // for how to handle it.
3670    if (TagFromDeclSpec->hasLinkageBeenComputed()) {
3671      Diag(NewTD->getLocation(), diag::err_typedef_changes_linkage);
3672  
3673      SourceLocation tagLoc = TagFromDeclSpec->getInnerLocStart();
3674      tagLoc = getLocForEndOfToken(tagLoc);
3675  
3676      llvm::SmallString<40> textToInsert;
3677      textToInsert += ' ';
3678      textToInsert += NewTD->getIdentifier()->getName();
3679      Diag(tagLoc, diag::note_typedef_changes_linkage)
3680          << FixItHint::CreateInsertion(tagLoc, textToInsert);
3681      return;
3682    }
3683  
3684    // Otherwise, set this is the anon-decl typedef for the tag.
3685    TagFromDeclSpec->setTypedefNameForAnonDecl(NewTD);
3686  }
3687  
GetDiagnosticTypeSpecifierID(DeclSpec::TST T)3688  static unsigned GetDiagnosticTypeSpecifierID(DeclSpec::TST T) {
3689    switch (T) {
3690    case DeclSpec::TST_class:
3691      return 0;
3692    case DeclSpec::TST_struct:
3693      return 1;
3694    case DeclSpec::TST_interface:
3695      return 2;
3696    case DeclSpec::TST_union:
3697      return 3;
3698    case DeclSpec::TST_enum:
3699      return 4;
3700    default:
3701      llvm_unreachable("unexpected type specifier");
3702    }
3703  }
3704  
3705  /// ParsedFreeStandingDeclSpec - This method is invoked when a declspec with
3706  /// no declarator (e.g. "struct foo;") is parsed. It also accepts template
3707  /// parameters to cope with template friend declarations.
ParsedFreeStandingDeclSpec(Scope * S,AccessSpecifier AS,DeclSpec & DS,MultiTemplateParamsArg TemplateParams,bool IsExplicitInstantiation)3708  Decl *Sema::ParsedFreeStandingDeclSpec(Scope *S, AccessSpecifier AS,
3709                                         DeclSpec &DS,
3710                                         MultiTemplateParamsArg TemplateParams,
3711                                         bool IsExplicitInstantiation) {
3712    Decl *TagD = nullptr;
3713    TagDecl *Tag = nullptr;
3714    if (DS.getTypeSpecType() == DeclSpec::TST_class ||
3715        DS.getTypeSpecType() == DeclSpec::TST_struct ||
3716        DS.getTypeSpecType() == DeclSpec::TST_interface ||
3717        DS.getTypeSpecType() == DeclSpec::TST_union ||
3718        DS.getTypeSpecType() == DeclSpec::TST_enum) {
3719      TagD = DS.getRepAsDecl();
3720  
3721      if (!TagD) // We probably had an error
3722        return nullptr;
3723  
3724      // Note that the above type specs guarantee that the
3725      // type rep is a Decl, whereas in many of the others
3726      // it's a Type.
3727      if (isa<TagDecl>(TagD))
3728        Tag = cast<TagDecl>(TagD);
3729      else if (ClassTemplateDecl *CTD = dyn_cast<ClassTemplateDecl>(TagD))
3730        Tag = CTD->getTemplatedDecl();
3731    }
3732  
3733    if (Tag) {
3734      handleTagNumbering(Tag, S);
3735      Tag->setFreeStanding();
3736      if (Tag->isInvalidDecl())
3737        return Tag;
3738    }
3739  
3740    if (unsigned TypeQuals = DS.getTypeQualifiers()) {
3741      // Enforce C99 6.7.3p2: "Types other than pointer types derived from object
3742      // or incomplete types shall not be restrict-qualified."
3743      if (TypeQuals & DeclSpec::TQ_restrict)
3744        Diag(DS.getRestrictSpecLoc(),
3745             diag::err_typecheck_invalid_restrict_not_pointer_noarg)
3746             << DS.getSourceRange();
3747    }
3748  
3749    if (DS.isConstexprSpecified()) {
3750      // C++0x [dcl.constexpr]p1: constexpr can only be applied to declarations
3751      // and definitions of functions and variables.
3752      if (Tag)
3753        Diag(DS.getConstexprSpecLoc(), diag::err_constexpr_tag)
3754            << GetDiagnosticTypeSpecifierID(DS.getTypeSpecType());
3755      else
3756        Diag(DS.getConstexprSpecLoc(), diag::err_constexpr_no_declarators);
3757      // Don't emit warnings after this error.
3758      return TagD;
3759    }
3760  
3761    if (DS.isConceptSpecified()) {
3762      // C++ Concepts TS [dcl.spec.concept]p1: A concept definition refers to
3763      // either a function concept and its definition or a variable concept and
3764      // its initializer.
3765      Diag(DS.getConceptSpecLoc(), diag::err_concept_wrong_decl_kind);
3766      return TagD;
3767    }
3768  
3769    DiagnoseFunctionSpecifiers(DS);
3770  
3771    if (DS.isFriendSpecified()) {
3772      // If we're dealing with a decl but not a TagDecl, assume that
3773      // whatever routines created it handled the friendship aspect.
3774      if (TagD && !Tag)
3775        return nullptr;
3776      return ActOnFriendTypeDecl(S, DS, TemplateParams);
3777    }
3778  
3779    const CXXScopeSpec &SS = DS.getTypeSpecScope();
3780    bool IsExplicitSpecialization =
3781      !TemplateParams.empty() && TemplateParams.back()->size() == 0;
3782    if (Tag && SS.isNotEmpty() && !Tag->isCompleteDefinition() &&
3783        !IsExplicitInstantiation && !IsExplicitSpecialization &&
3784        !isa<ClassTemplatePartialSpecializationDecl>(Tag)) {
3785      // Per C++ [dcl.type.elab]p1, a class declaration cannot have a
3786      // nested-name-specifier unless it is an explicit instantiation
3787      // or an explicit specialization.
3788      //
3789      // FIXME: We allow class template partial specializations here too, per the
3790      // obvious intent of DR1819.
3791      //
3792      // Per C++ [dcl.enum]p1, an opaque-enum-declaration can't either.
3793      Diag(SS.getBeginLoc(), diag::err_standalone_class_nested_name_specifier)
3794          << GetDiagnosticTypeSpecifierID(DS.getTypeSpecType()) << SS.getRange();
3795      return nullptr;
3796    }
3797  
3798    // Track whether this decl-specifier declares anything.
3799    bool DeclaresAnything = true;
3800  
3801    // Handle anonymous struct definitions.
3802    if (RecordDecl *Record = dyn_cast_or_null<RecordDecl>(Tag)) {
3803      if (!Record->getDeclName() && Record->isCompleteDefinition() &&
3804          DS.getStorageClassSpec() != DeclSpec::SCS_typedef) {
3805        if (getLangOpts().CPlusPlus ||
3806            Record->getDeclContext()->isRecord())
3807          return BuildAnonymousStructOrUnion(S, DS, AS, Record,
3808                                             Context.getPrintingPolicy());
3809  
3810        DeclaresAnything = false;
3811      }
3812    }
3813  
3814    // C11 6.7.2.1p2:
3815    //   A struct-declaration that does not declare an anonymous structure or
3816    //   anonymous union shall contain a struct-declarator-list.
3817    //
3818    // This rule also existed in C89 and C99; the grammar for struct-declaration
3819    // did not permit a struct-declaration without a struct-declarator-list.
3820    if (!getLangOpts().CPlusPlus && CurContext->isRecord() &&
3821        DS.getStorageClassSpec() == DeclSpec::SCS_unspecified) {
3822      // Check for Microsoft C extension: anonymous struct/union member.
3823      // Handle 2 kinds of anonymous struct/union:
3824      //   struct STRUCT;
3825      //   union UNION;
3826      // and
3827      //   STRUCT_TYPE;  <- where STRUCT_TYPE is a typedef struct.
3828      //   UNION_TYPE;   <- where UNION_TYPE is a typedef union.
3829      if ((Tag && Tag->getDeclName()) ||
3830          DS.getTypeSpecType() == DeclSpec::TST_typename) {
3831        RecordDecl *Record = nullptr;
3832        if (Tag)
3833          Record = dyn_cast<RecordDecl>(Tag);
3834        else if (const RecordType *RT =
3835                     DS.getRepAsType().get()->getAsStructureType())
3836          Record = RT->getDecl();
3837        else if (const RecordType *UT = DS.getRepAsType().get()->getAsUnionType())
3838          Record = UT->getDecl();
3839  
3840        if (Record && getLangOpts().MicrosoftExt) {
3841          Diag(DS.getLocStart(), diag::ext_ms_anonymous_record)
3842            << Record->isUnion() << DS.getSourceRange();
3843          return BuildMicrosoftCAnonymousStruct(S, DS, Record);
3844        }
3845  
3846        DeclaresAnything = false;
3847      }
3848    }
3849  
3850    // Skip all the checks below if we have a type error.
3851    if (DS.getTypeSpecType() == DeclSpec::TST_error ||
3852        (TagD && TagD->isInvalidDecl()))
3853      return TagD;
3854  
3855    if (getLangOpts().CPlusPlus &&
3856        DS.getStorageClassSpec() != DeclSpec::SCS_typedef)
3857      if (EnumDecl *Enum = dyn_cast_or_null<EnumDecl>(Tag))
3858        if (Enum->enumerator_begin() == Enum->enumerator_end() &&
3859            !Enum->getIdentifier() && !Enum->isInvalidDecl())
3860          DeclaresAnything = false;
3861  
3862    if (!DS.isMissingDeclaratorOk()) {
3863      // Customize diagnostic for a typedef missing a name.
3864      if (DS.getStorageClassSpec() == DeclSpec::SCS_typedef)
3865        Diag(DS.getLocStart(), diag::ext_typedef_without_a_name)
3866          << DS.getSourceRange();
3867      else
3868        DeclaresAnything = false;
3869    }
3870  
3871    if (DS.isModulePrivateSpecified() &&
3872        Tag && Tag->getDeclContext()->isFunctionOrMethod())
3873      Diag(DS.getModulePrivateSpecLoc(), diag::err_module_private_local_class)
3874        << Tag->getTagKind()
3875        << FixItHint::CreateRemoval(DS.getModulePrivateSpecLoc());
3876  
3877    ActOnDocumentableDecl(TagD);
3878  
3879    // C 6.7/2:
3880    //   A declaration [...] shall declare at least a declarator [...], a tag,
3881    //   or the members of an enumeration.
3882    // C++ [dcl.dcl]p3:
3883    //   [If there are no declarators], and except for the declaration of an
3884    //   unnamed bit-field, the decl-specifier-seq shall introduce one or more
3885    //   names into the program, or shall redeclare a name introduced by a
3886    //   previous declaration.
3887    if (!DeclaresAnything) {
3888      // In C, we allow this as a (popular) extension / bug. Don't bother
3889      // producing further diagnostics for redundant qualifiers after this.
3890      Diag(DS.getLocStart(), diag::ext_no_declarators) << DS.getSourceRange();
3891      return TagD;
3892    }
3893  
3894    // C++ [dcl.stc]p1:
3895    //   If a storage-class-specifier appears in a decl-specifier-seq, [...] the
3896    //   init-declarator-list of the declaration shall not be empty.
3897    // C++ [dcl.fct.spec]p1:
3898    //   If a cv-qualifier appears in a decl-specifier-seq, the
3899    //   init-declarator-list of the declaration shall not be empty.
3900    //
3901    // Spurious qualifiers here appear to be valid in C.
3902    unsigned DiagID = diag::warn_standalone_specifier;
3903    if (getLangOpts().CPlusPlus)
3904      DiagID = diag::ext_standalone_specifier;
3905  
3906    // Note that a linkage-specification sets a storage class, but
3907    // 'extern "C" struct foo;' is actually valid and not theoretically
3908    // useless.
3909    if (DeclSpec::SCS SCS = DS.getStorageClassSpec()) {
3910      if (SCS == DeclSpec::SCS_mutable)
3911        // Since mutable is not a viable storage class specifier in C, there is
3912        // no reason to treat it as an extension. Instead, diagnose as an error.
3913        Diag(DS.getStorageClassSpecLoc(), diag::err_mutable_nonmember);
3914      else if (!DS.isExternInLinkageSpec() && SCS != DeclSpec::SCS_typedef)
3915        Diag(DS.getStorageClassSpecLoc(), DiagID)
3916          << DeclSpec::getSpecifierName(SCS);
3917    }
3918  
3919    if (DeclSpec::TSCS TSCS = DS.getThreadStorageClassSpec())
3920      Diag(DS.getThreadStorageClassSpecLoc(), DiagID)
3921        << DeclSpec::getSpecifierName(TSCS);
3922    if (DS.getTypeQualifiers()) {
3923      if (DS.getTypeQualifiers() & DeclSpec::TQ_const)
3924        Diag(DS.getConstSpecLoc(), DiagID) << "const";
3925      if (DS.getTypeQualifiers() & DeclSpec::TQ_volatile)
3926        Diag(DS.getConstSpecLoc(), DiagID) << "volatile";
3927      // Restrict is covered above.
3928      if (DS.getTypeQualifiers() & DeclSpec::TQ_atomic)
3929        Diag(DS.getAtomicSpecLoc(), DiagID) << "_Atomic";
3930    }
3931  
3932    // Warn about ignored type attributes, for example:
3933    // __attribute__((aligned)) struct A;
3934    // Attributes should be placed after tag to apply to type declaration.
3935    if (!DS.getAttributes().empty()) {
3936      DeclSpec::TST TypeSpecType = DS.getTypeSpecType();
3937      if (TypeSpecType == DeclSpec::TST_class ||
3938          TypeSpecType == DeclSpec::TST_struct ||
3939          TypeSpecType == DeclSpec::TST_interface ||
3940          TypeSpecType == DeclSpec::TST_union ||
3941          TypeSpecType == DeclSpec::TST_enum) {
3942        for (AttributeList* attrs = DS.getAttributes().getList(); attrs;
3943             attrs = attrs->getNext())
3944          Diag(attrs->getLoc(), diag::warn_declspec_attribute_ignored)
3945              << attrs->getName() << GetDiagnosticTypeSpecifierID(TypeSpecType);
3946      }
3947    }
3948  
3949    return TagD;
3950  }
3951  
3952  /// We are trying to inject an anonymous member into the given scope;
3953  /// check if there's an existing declaration that can't be overloaded.
3954  ///
3955  /// \return true if this is a forbidden redeclaration
CheckAnonMemberRedeclaration(Sema & SemaRef,Scope * S,DeclContext * Owner,DeclarationName Name,SourceLocation NameLoc,bool IsUnion)3956  static bool CheckAnonMemberRedeclaration(Sema &SemaRef,
3957                                           Scope *S,
3958                                           DeclContext *Owner,
3959                                           DeclarationName Name,
3960                                           SourceLocation NameLoc,
3961                                           bool IsUnion) {
3962    LookupResult R(SemaRef, Name, NameLoc, Sema::LookupMemberName,
3963                   Sema::ForRedeclaration);
3964    if (!SemaRef.LookupName(R, S)) return false;
3965  
3966    if (R.getAsSingle<TagDecl>())
3967      return false;
3968  
3969    // Pick a representative declaration.
3970    NamedDecl *PrevDecl = R.getRepresentativeDecl()->getUnderlyingDecl();
3971    assert(PrevDecl && "Expected a non-null Decl");
3972  
3973    if (!SemaRef.isDeclInScope(PrevDecl, Owner, S))
3974      return false;
3975  
3976    SemaRef.Diag(NameLoc, diag::err_anonymous_record_member_redecl)
3977      << IsUnion << Name;
3978    SemaRef.Diag(PrevDecl->getLocation(), diag::note_previous_declaration);
3979  
3980    return true;
3981  }
3982  
3983  /// InjectAnonymousStructOrUnionMembers - Inject the members of the
3984  /// anonymous struct or union AnonRecord into the owning context Owner
3985  /// and scope S. This routine will be invoked just after we realize
3986  /// that an unnamed union or struct is actually an anonymous union or
3987  /// struct, e.g.,
3988  ///
3989  /// @code
3990  /// union {
3991  ///   int i;
3992  ///   float f;
3993  /// }; // InjectAnonymousStructOrUnionMembers called here to inject i and
3994  ///    // f into the surrounding scope.x
3995  /// @endcode
3996  ///
3997  /// This routine is recursive, injecting the names of nested anonymous
3998  /// structs/unions into the owning context and scope as well.
InjectAnonymousStructOrUnionMembers(Sema & SemaRef,Scope * S,DeclContext * Owner,RecordDecl * AnonRecord,AccessSpecifier AS,SmallVectorImpl<NamedDecl * > & Chaining,bool MSAnonStruct)3999  static bool InjectAnonymousStructOrUnionMembers(Sema &SemaRef, Scope *S,
4000                                           DeclContext *Owner,
4001                                           RecordDecl *AnonRecord,
4002                                           AccessSpecifier AS,
4003                                           SmallVectorImpl<NamedDecl *> &Chaining,
4004                                           bool MSAnonStruct) {
4005    bool Invalid = false;
4006  
4007    // Look every FieldDecl and IndirectFieldDecl with a name.
4008    for (auto *D : AnonRecord->decls()) {
4009      if ((isa<FieldDecl>(D) || isa<IndirectFieldDecl>(D)) &&
4010          cast<NamedDecl>(D)->getDeclName()) {
4011        ValueDecl *VD = cast<ValueDecl>(D);
4012        if (CheckAnonMemberRedeclaration(SemaRef, S, Owner, VD->getDeclName(),
4013                                         VD->getLocation(),
4014                                         AnonRecord->isUnion())) {
4015          // C++ [class.union]p2:
4016          //   The names of the members of an anonymous union shall be
4017          //   distinct from the names of any other entity in the
4018          //   scope in which the anonymous union is declared.
4019          Invalid = true;
4020        } else {
4021          // C++ [class.union]p2:
4022          //   For the purpose of name lookup, after the anonymous union
4023          //   definition, the members of the anonymous union are
4024          //   considered to have been defined in the scope in which the
4025          //   anonymous union is declared.
4026          unsigned OldChainingSize = Chaining.size();
4027          if (IndirectFieldDecl *IF = dyn_cast<IndirectFieldDecl>(VD))
4028            Chaining.append(IF->chain_begin(), IF->chain_end());
4029          else
4030            Chaining.push_back(VD);
4031  
4032          assert(Chaining.size() >= 2);
4033          NamedDecl **NamedChain =
4034            new (SemaRef.Context)NamedDecl*[Chaining.size()];
4035          for (unsigned i = 0; i < Chaining.size(); i++)
4036            NamedChain[i] = Chaining[i];
4037  
4038          IndirectFieldDecl *IndirectField = IndirectFieldDecl::Create(
4039              SemaRef.Context, Owner, VD->getLocation(), VD->getIdentifier(),
4040              VD->getType(), NamedChain, Chaining.size());
4041  
4042          for (const auto *Attr : VD->attrs())
4043            IndirectField->addAttr(Attr->clone(SemaRef.Context));
4044  
4045          IndirectField->setAccess(AS);
4046          IndirectField->setImplicit();
4047          SemaRef.PushOnScopeChains(IndirectField, S);
4048  
4049          // That includes picking up the appropriate access specifier.
4050          if (AS != AS_none) IndirectField->setAccess(AS);
4051  
4052          Chaining.resize(OldChainingSize);
4053        }
4054      }
4055    }
4056  
4057    return Invalid;
4058  }
4059  
4060  /// StorageClassSpecToVarDeclStorageClass - Maps a DeclSpec::SCS to
4061  /// a VarDecl::StorageClass. Any error reporting is up to the caller:
4062  /// illegal input values are mapped to SC_None.
4063  static StorageClass
StorageClassSpecToVarDeclStorageClass(const DeclSpec & DS)4064  StorageClassSpecToVarDeclStorageClass(const DeclSpec &DS) {
4065    DeclSpec::SCS StorageClassSpec = DS.getStorageClassSpec();
4066    assert(StorageClassSpec != DeclSpec::SCS_typedef &&
4067           "Parser allowed 'typedef' as storage class VarDecl.");
4068    switch (StorageClassSpec) {
4069    case DeclSpec::SCS_unspecified:    return SC_None;
4070    case DeclSpec::SCS_extern:
4071      if (DS.isExternInLinkageSpec())
4072        return SC_None;
4073      return SC_Extern;
4074    case DeclSpec::SCS_static:         return SC_Static;
4075    case DeclSpec::SCS_auto:           return SC_Auto;
4076    case DeclSpec::SCS_register:       return SC_Register;
4077    case DeclSpec::SCS_private_extern: return SC_PrivateExtern;
4078      // Illegal SCSs map to None: error reporting is up to the caller.
4079    case DeclSpec::SCS_mutable:        // Fall through.
4080    case DeclSpec::SCS_typedef:        return SC_None;
4081    }
4082    llvm_unreachable("unknown storage class specifier");
4083  }
4084  
findDefaultInitializer(const CXXRecordDecl * Record)4085  static SourceLocation findDefaultInitializer(const CXXRecordDecl *Record) {
4086    assert(Record->hasInClassInitializer());
4087  
4088    for (const auto *I : Record->decls()) {
4089      const auto *FD = dyn_cast<FieldDecl>(I);
4090      if (const auto *IFD = dyn_cast<IndirectFieldDecl>(I))
4091        FD = IFD->getAnonField();
4092      if (FD && FD->hasInClassInitializer())
4093        return FD->getLocation();
4094    }
4095  
4096    llvm_unreachable("couldn't find in-class initializer");
4097  }
4098  
checkDuplicateDefaultInit(Sema & S,CXXRecordDecl * Parent,SourceLocation DefaultInitLoc)4099  static void checkDuplicateDefaultInit(Sema &S, CXXRecordDecl *Parent,
4100                                        SourceLocation DefaultInitLoc) {
4101    if (!Parent->isUnion() || !Parent->hasInClassInitializer())
4102      return;
4103  
4104    S.Diag(DefaultInitLoc, diag::err_multiple_mem_union_initialization);
4105    S.Diag(findDefaultInitializer(Parent), diag::note_previous_initializer) << 0;
4106  }
4107  
checkDuplicateDefaultInit(Sema & S,CXXRecordDecl * Parent,CXXRecordDecl * AnonUnion)4108  static void checkDuplicateDefaultInit(Sema &S, CXXRecordDecl *Parent,
4109                                        CXXRecordDecl *AnonUnion) {
4110    if (!Parent->isUnion() || !Parent->hasInClassInitializer())
4111      return;
4112  
4113    checkDuplicateDefaultInit(S, Parent, findDefaultInitializer(AnonUnion));
4114  }
4115  
4116  /// BuildAnonymousStructOrUnion - Handle the declaration of an
4117  /// anonymous structure or union. Anonymous unions are a C++ feature
4118  /// (C++ [class.union]) and a C11 feature; anonymous structures
4119  /// are a C11 feature and GNU C++ extension.
BuildAnonymousStructOrUnion(Scope * S,DeclSpec & DS,AccessSpecifier AS,RecordDecl * Record,const PrintingPolicy & Policy)4120  Decl *Sema::BuildAnonymousStructOrUnion(Scope *S, DeclSpec &DS,
4121                                          AccessSpecifier AS,
4122                                          RecordDecl *Record,
4123                                          const PrintingPolicy &Policy) {
4124    DeclContext *Owner = Record->getDeclContext();
4125  
4126    // Diagnose whether this anonymous struct/union is an extension.
4127    if (Record->isUnion() && !getLangOpts().CPlusPlus && !getLangOpts().C11)
4128      Diag(Record->getLocation(), diag::ext_anonymous_union);
4129    else if (!Record->isUnion() && getLangOpts().CPlusPlus)
4130      Diag(Record->getLocation(), diag::ext_gnu_anonymous_struct);
4131    else if (!Record->isUnion() && !getLangOpts().C11)
4132      Diag(Record->getLocation(), diag::ext_c11_anonymous_struct);
4133  
4134    // C and C++ require different kinds of checks for anonymous
4135    // structs/unions.
4136    bool Invalid = false;
4137    if (getLangOpts().CPlusPlus) {
4138      const char *PrevSpec = nullptr;
4139      unsigned DiagID;
4140      if (Record->isUnion()) {
4141        // C++ [class.union]p6:
4142        //   Anonymous unions declared in a named namespace or in the
4143        //   global namespace shall be declared static.
4144        if (DS.getStorageClassSpec() != DeclSpec::SCS_static &&
4145            (isa<TranslationUnitDecl>(Owner) ||
4146             (isa<NamespaceDecl>(Owner) &&
4147              cast<NamespaceDecl>(Owner)->getDeclName()))) {
4148          Diag(Record->getLocation(), diag::err_anonymous_union_not_static)
4149            << FixItHint::CreateInsertion(Record->getLocation(), "static ");
4150  
4151          // Recover by adding 'static'.
4152          DS.SetStorageClassSpec(*this, DeclSpec::SCS_static, SourceLocation(),
4153                                 PrevSpec, DiagID, Policy);
4154        }
4155        // C++ [class.union]p6:
4156        //   A storage class is not allowed in a declaration of an
4157        //   anonymous union in a class scope.
4158        else if (DS.getStorageClassSpec() != DeclSpec::SCS_unspecified &&
4159                 isa<RecordDecl>(Owner)) {
4160          Diag(DS.getStorageClassSpecLoc(),
4161               diag::err_anonymous_union_with_storage_spec)
4162            << FixItHint::CreateRemoval(DS.getStorageClassSpecLoc());
4163  
4164          // Recover by removing the storage specifier.
4165          DS.SetStorageClassSpec(*this, DeclSpec::SCS_unspecified,
4166                                 SourceLocation(),
4167                                 PrevSpec, DiagID, Context.getPrintingPolicy());
4168        }
4169      }
4170  
4171      // Ignore const/volatile/restrict qualifiers.
4172      if (DS.getTypeQualifiers()) {
4173        if (DS.getTypeQualifiers() & DeclSpec::TQ_const)
4174          Diag(DS.getConstSpecLoc(), diag::ext_anonymous_struct_union_qualified)
4175            << Record->isUnion() << "const"
4176            << FixItHint::CreateRemoval(DS.getConstSpecLoc());
4177        if (DS.getTypeQualifiers() & DeclSpec::TQ_volatile)
4178          Diag(DS.getVolatileSpecLoc(),
4179               diag::ext_anonymous_struct_union_qualified)
4180            << Record->isUnion() << "volatile"
4181            << FixItHint::CreateRemoval(DS.getVolatileSpecLoc());
4182        if (DS.getTypeQualifiers() & DeclSpec::TQ_restrict)
4183          Diag(DS.getRestrictSpecLoc(),
4184               diag::ext_anonymous_struct_union_qualified)
4185            << Record->isUnion() << "restrict"
4186            << FixItHint::CreateRemoval(DS.getRestrictSpecLoc());
4187        if (DS.getTypeQualifiers() & DeclSpec::TQ_atomic)
4188          Diag(DS.getAtomicSpecLoc(),
4189               diag::ext_anonymous_struct_union_qualified)
4190            << Record->isUnion() << "_Atomic"
4191            << FixItHint::CreateRemoval(DS.getAtomicSpecLoc());
4192  
4193        DS.ClearTypeQualifiers();
4194      }
4195  
4196      // C++ [class.union]p2:
4197      //   The member-specification of an anonymous union shall only
4198      //   define non-static data members. [Note: nested types and
4199      //   functions cannot be declared within an anonymous union. ]
4200      for (auto *Mem : Record->decls()) {
4201        if (auto *FD = dyn_cast<FieldDecl>(Mem)) {
4202          // C++ [class.union]p3:
4203          //   An anonymous union shall not have private or protected
4204          //   members (clause 11).
4205          assert(FD->getAccess() != AS_none);
4206          if (FD->getAccess() != AS_public) {
4207            Diag(FD->getLocation(), diag::err_anonymous_record_nonpublic_member)
4208              << Record->isUnion() << (FD->getAccess() == AS_protected);
4209            Invalid = true;
4210          }
4211  
4212          // C++ [class.union]p1
4213          //   An object of a class with a non-trivial constructor, a non-trivial
4214          //   copy constructor, a non-trivial destructor, or a non-trivial copy
4215          //   assignment operator cannot be a member of a union, nor can an
4216          //   array of such objects.
4217          if (CheckNontrivialField(FD))
4218            Invalid = true;
4219        } else if (Mem->isImplicit()) {
4220          // Any implicit members are fine.
4221        } else if (isa<TagDecl>(Mem) && Mem->getDeclContext() != Record) {
4222          // This is a type that showed up in an
4223          // elaborated-type-specifier inside the anonymous struct or
4224          // union, but which actually declares a type outside of the
4225          // anonymous struct or union. It's okay.
4226        } else if (auto *MemRecord = dyn_cast<RecordDecl>(Mem)) {
4227          if (!MemRecord->isAnonymousStructOrUnion() &&
4228              MemRecord->getDeclName()) {
4229            // Visual C++ allows type definition in anonymous struct or union.
4230            if (getLangOpts().MicrosoftExt)
4231              Diag(MemRecord->getLocation(), diag::ext_anonymous_record_with_type)
4232                << Record->isUnion();
4233            else {
4234              // This is a nested type declaration.
4235              Diag(MemRecord->getLocation(), diag::err_anonymous_record_with_type)
4236                << Record->isUnion();
4237              Invalid = true;
4238            }
4239          } else {
4240            // This is an anonymous type definition within another anonymous type.
4241            // This is a popular extension, provided by Plan9, MSVC and GCC, but
4242            // not part of standard C++.
4243            Diag(MemRecord->getLocation(),
4244                 diag::ext_anonymous_record_with_anonymous_type)
4245              << Record->isUnion();
4246          }
4247        } else if (isa<AccessSpecDecl>(Mem)) {
4248          // Any access specifier is fine.
4249        } else if (isa<StaticAssertDecl>(Mem)) {
4250          // In C++1z, static_assert declarations are also fine.
4251        } else {
4252          // We have something that isn't a non-static data
4253          // member. Complain about it.
4254          unsigned DK = diag::err_anonymous_record_bad_member;
4255          if (isa<TypeDecl>(Mem))
4256            DK = diag::err_anonymous_record_with_type;
4257          else if (isa<FunctionDecl>(Mem))
4258            DK = diag::err_anonymous_record_with_function;
4259          else if (isa<VarDecl>(Mem))
4260            DK = diag::err_anonymous_record_with_static;
4261  
4262          // Visual C++ allows type definition in anonymous struct or union.
4263          if (getLangOpts().MicrosoftExt &&
4264              DK == diag::err_anonymous_record_with_type)
4265            Diag(Mem->getLocation(), diag::ext_anonymous_record_with_type)
4266              << Record->isUnion();
4267          else {
4268            Diag(Mem->getLocation(), DK) << Record->isUnion();
4269            Invalid = true;
4270          }
4271        }
4272      }
4273  
4274      // C++11 [class.union]p8 (DR1460):
4275      //   At most one variant member of a union may have a
4276      //   brace-or-equal-initializer.
4277      if (cast<CXXRecordDecl>(Record)->hasInClassInitializer() &&
4278          Owner->isRecord())
4279        checkDuplicateDefaultInit(*this, cast<CXXRecordDecl>(Owner),
4280                                  cast<CXXRecordDecl>(Record));
4281    }
4282  
4283    if (!Record->isUnion() && !Owner->isRecord()) {
4284      Diag(Record->getLocation(), diag::err_anonymous_struct_not_member)
4285        << getLangOpts().CPlusPlus;
4286      Invalid = true;
4287    }
4288  
4289    // Mock up a declarator.
4290    Declarator Dc(DS, Declarator::MemberContext);
4291    TypeSourceInfo *TInfo = GetTypeForDeclarator(Dc, S);
4292    assert(TInfo && "couldn't build declarator info for anonymous struct/union");
4293  
4294    // Create a declaration for this anonymous struct/union.
4295    NamedDecl *Anon = nullptr;
4296    if (RecordDecl *OwningClass = dyn_cast<RecordDecl>(Owner)) {
4297      Anon = FieldDecl::Create(Context, OwningClass,
4298                               DS.getLocStart(),
4299                               Record->getLocation(),
4300                               /*IdentifierInfo=*/nullptr,
4301                               Context.getTypeDeclType(Record),
4302                               TInfo,
4303                               /*BitWidth=*/nullptr, /*Mutable=*/false,
4304                               /*InitStyle=*/ICIS_NoInit);
4305      Anon->setAccess(AS);
4306      if (getLangOpts().CPlusPlus)
4307        FieldCollector->Add(cast<FieldDecl>(Anon));
4308    } else {
4309      DeclSpec::SCS SCSpec = DS.getStorageClassSpec();
4310      StorageClass SC = StorageClassSpecToVarDeclStorageClass(DS);
4311      if (SCSpec == DeclSpec::SCS_mutable) {
4312        // mutable can only appear on non-static class members, so it's always
4313        // an error here
4314        Diag(Record->getLocation(), diag::err_mutable_nonmember);
4315        Invalid = true;
4316        SC = SC_None;
4317      }
4318  
4319      Anon = VarDecl::Create(Context, Owner,
4320                             DS.getLocStart(),
4321                             Record->getLocation(), /*IdentifierInfo=*/nullptr,
4322                             Context.getTypeDeclType(Record),
4323                             TInfo, SC);
4324  
4325      // Default-initialize the implicit variable. This initialization will be
4326      // trivial in almost all cases, except if a union member has an in-class
4327      // initializer:
4328      //   union { int n = 0; };
4329      ActOnUninitializedDecl(Anon, /*TypeMayContainAuto=*/false);
4330    }
4331    Anon->setImplicit();
4332  
4333    // Mark this as an anonymous struct/union type.
4334    Record->setAnonymousStructOrUnion(true);
4335  
4336    // Add the anonymous struct/union object to the current
4337    // context. We'll be referencing this object when we refer to one of
4338    // its members.
4339    Owner->addDecl(Anon);
4340  
4341    // Inject the members of the anonymous struct/union into the owning
4342    // context and into the identifier resolver chain for name lookup
4343    // purposes.
4344    SmallVector<NamedDecl*, 2> Chain;
4345    Chain.push_back(Anon);
4346  
4347    if (InjectAnonymousStructOrUnionMembers(*this, S, Owner, Record, AS,
4348                                            Chain, false))
4349      Invalid = true;
4350  
4351    if (VarDecl *NewVD = dyn_cast<VarDecl>(Anon)) {
4352      if (getLangOpts().CPlusPlus && NewVD->isStaticLocal()) {
4353        Decl *ManglingContextDecl;
4354        if (MangleNumberingContext *MCtx = getCurrentMangleNumberContext(
4355                NewVD->getDeclContext(), ManglingContextDecl)) {
4356          Context.setManglingNumber(
4357              NewVD, MCtx->getManglingNumber(
4358                         NewVD, getMSManglingNumber(getLangOpts(), S)));
4359          Context.setStaticLocalNumber(NewVD, MCtx->getStaticLocalNumber(NewVD));
4360        }
4361      }
4362    }
4363  
4364    if (Invalid)
4365      Anon->setInvalidDecl();
4366  
4367    return Anon;
4368  }
4369  
4370  /// BuildMicrosoftCAnonymousStruct - Handle the declaration of an
4371  /// Microsoft C anonymous structure.
4372  /// Ref: http://msdn.microsoft.com/en-us/library/z2cx9y4f.aspx
4373  /// Example:
4374  ///
4375  /// struct A { int a; };
4376  /// struct B { struct A; int b; };
4377  ///
4378  /// void foo() {
4379  ///   B var;
4380  ///   var.a = 3;
4381  /// }
4382  ///
BuildMicrosoftCAnonymousStruct(Scope * S,DeclSpec & DS,RecordDecl * Record)4383  Decl *Sema::BuildMicrosoftCAnonymousStruct(Scope *S, DeclSpec &DS,
4384                                             RecordDecl *Record) {
4385    assert(Record && "expected a record!");
4386  
4387    // Mock up a declarator.
4388    Declarator Dc(DS, Declarator::TypeNameContext);
4389    TypeSourceInfo *TInfo = GetTypeForDeclarator(Dc, S);
4390    assert(TInfo && "couldn't build declarator info for anonymous struct");
4391  
4392    auto *ParentDecl = cast<RecordDecl>(CurContext);
4393    QualType RecTy = Context.getTypeDeclType(Record);
4394  
4395    // Create a declaration for this anonymous struct.
4396    NamedDecl *Anon = FieldDecl::Create(Context,
4397                               ParentDecl,
4398                               DS.getLocStart(),
4399                               DS.getLocStart(),
4400                               /*IdentifierInfo=*/nullptr,
4401                               RecTy,
4402                               TInfo,
4403                               /*BitWidth=*/nullptr, /*Mutable=*/false,
4404                               /*InitStyle=*/ICIS_NoInit);
4405    Anon->setImplicit();
4406  
4407    // Add the anonymous struct object to the current context.
4408    CurContext->addDecl(Anon);
4409  
4410    // Inject the members of the anonymous struct into the current
4411    // context and into the identifier resolver chain for name lookup
4412    // purposes.
4413    SmallVector<NamedDecl*, 2> Chain;
4414    Chain.push_back(Anon);
4415  
4416    RecordDecl *RecordDef = Record->getDefinition();
4417    if (RequireCompleteType(Anon->getLocation(), RecTy,
4418                            diag::err_field_incomplete) ||
4419        InjectAnonymousStructOrUnionMembers(*this, S, CurContext, RecordDef,
4420                                            AS_none, Chain, true)) {
4421      Anon->setInvalidDecl();
4422      ParentDecl->setInvalidDecl();
4423    }
4424  
4425    return Anon;
4426  }
4427  
4428  /// GetNameForDeclarator - Determine the full declaration name for the
4429  /// given Declarator.
GetNameForDeclarator(Declarator & D)4430  DeclarationNameInfo Sema::GetNameForDeclarator(Declarator &D) {
4431    return GetNameFromUnqualifiedId(D.getName());
4432  }
4433  
4434  /// \brief Retrieves the declaration name from a parsed unqualified-id.
4435  DeclarationNameInfo
GetNameFromUnqualifiedId(const UnqualifiedId & Name)4436  Sema::GetNameFromUnqualifiedId(const UnqualifiedId &Name) {
4437    DeclarationNameInfo NameInfo;
4438    NameInfo.setLoc(Name.StartLocation);
4439  
4440    switch (Name.getKind()) {
4441  
4442    case UnqualifiedId::IK_ImplicitSelfParam:
4443    case UnqualifiedId::IK_Identifier:
4444      NameInfo.setName(Name.Identifier);
4445      NameInfo.setLoc(Name.StartLocation);
4446      return NameInfo;
4447  
4448    case UnqualifiedId::IK_OperatorFunctionId:
4449      NameInfo.setName(Context.DeclarationNames.getCXXOperatorName(
4450                                             Name.OperatorFunctionId.Operator));
4451      NameInfo.setLoc(Name.StartLocation);
4452      NameInfo.getInfo().CXXOperatorName.BeginOpNameLoc
4453        = Name.OperatorFunctionId.SymbolLocations[0];
4454      NameInfo.getInfo().CXXOperatorName.EndOpNameLoc
4455        = Name.EndLocation.getRawEncoding();
4456      return NameInfo;
4457  
4458    case UnqualifiedId::IK_LiteralOperatorId:
4459      NameInfo.setName(Context.DeclarationNames.getCXXLiteralOperatorName(
4460                                                             Name.Identifier));
4461      NameInfo.setLoc(Name.StartLocation);
4462      NameInfo.setCXXLiteralOperatorNameLoc(Name.EndLocation);
4463      return NameInfo;
4464  
4465    case UnqualifiedId::IK_ConversionFunctionId: {
4466      TypeSourceInfo *TInfo;
4467      QualType Ty = GetTypeFromParser(Name.ConversionFunctionId, &TInfo);
4468      if (Ty.isNull())
4469        return DeclarationNameInfo();
4470      NameInfo.setName(Context.DeclarationNames.getCXXConversionFunctionName(
4471                                                 Context.getCanonicalType(Ty)));
4472      NameInfo.setLoc(Name.StartLocation);
4473      NameInfo.setNamedTypeInfo(TInfo);
4474      return NameInfo;
4475    }
4476  
4477    case UnqualifiedId::IK_ConstructorName: {
4478      TypeSourceInfo *TInfo;
4479      QualType Ty = GetTypeFromParser(Name.ConstructorName, &TInfo);
4480      if (Ty.isNull())
4481        return DeclarationNameInfo();
4482      NameInfo.setName(Context.DeclarationNames.getCXXConstructorName(
4483                                                Context.getCanonicalType(Ty)));
4484      NameInfo.setLoc(Name.StartLocation);
4485      NameInfo.setNamedTypeInfo(TInfo);
4486      return NameInfo;
4487    }
4488  
4489    case UnqualifiedId::IK_ConstructorTemplateId: {
4490      // In well-formed code, we can only have a constructor
4491      // template-id that refers to the current context, so go there
4492      // to find the actual type being constructed.
4493      CXXRecordDecl *CurClass = dyn_cast<CXXRecordDecl>(CurContext);
4494      if (!CurClass || CurClass->getIdentifier() != Name.TemplateId->Name)
4495        return DeclarationNameInfo();
4496  
4497      // Determine the type of the class being constructed.
4498      QualType CurClassType = Context.getTypeDeclType(CurClass);
4499  
4500      // FIXME: Check two things: that the template-id names the same type as
4501      // CurClassType, and that the template-id does not occur when the name
4502      // was qualified.
4503  
4504      NameInfo.setName(Context.DeclarationNames.getCXXConstructorName(
4505                                      Context.getCanonicalType(CurClassType)));
4506      NameInfo.setLoc(Name.StartLocation);
4507      // FIXME: should we retrieve TypeSourceInfo?
4508      NameInfo.setNamedTypeInfo(nullptr);
4509      return NameInfo;
4510    }
4511  
4512    case UnqualifiedId::IK_DestructorName: {
4513      TypeSourceInfo *TInfo;
4514      QualType Ty = GetTypeFromParser(Name.DestructorName, &TInfo);
4515      if (Ty.isNull())
4516        return DeclarationNameInfo();
4517      NameInfo.setName(Context.DeclarationNames.getCXXDestructorName(
4518                                                Context.getCanonicalType(Ty)));
4519      NameInfo.setLoc(Name.StartLocation);
4520      NameInfo.setNamedTypeInfo(TInfo);
4521      return NameInfo;
4522    }
4523  
4524    case UnqualifiedId::IK_TemplateId: {
4525      TemplateName TName = Name.TemplateId->Template.get();
4526      SourceLocation TNameLoc = Name.TemplateId->TemplateNameLoc;
4527      return Context.getNameForTemplate(TName, TNameLoc);
4528    }
4529  
4530    } // switch (Name.getKind())
4531  
4532    llvm_unreachable("Unknown name kind");
4533  }
4534  
getCoreType(QualType Ty)4535  static QualType getCoreType(QualType Ty) {
4536    do {
4537      if (Ty->isPointerType() || Ty->isReferenceType())
4538        Ty = Ty->getPointeeType();
4539      else if (Ty->isArrayType())
4540        Ty = Ty->castAsArrayTypeUnsafe()->getElementType();
4541      else
4542        return Ty.withoutLocalFastQualifiers();
4543    } while (true);
4544  }
4545  
4546  /// hasSimilarParameters - Determine whether the C++ functions Declaration
4547  /// and Definition have "nearly" matching parameters. This heuristic is
4548  /// used to improve diagnostics in the case where an out-of-line function
4549  /// definition doesn't match any declaration within the class or namespace.
4550  /// Also sets Params to the list of indices to the parameters that differ
4551  /// between the declaration and the definition. If hasSimilarParameters
4552  /// returns true and Params is empty, then all of the parameters match.
hasSimilarParameters(ASTContext & Context,FunctionDecl * Declaration,FunctionDecl * Definition,SmallVectorImpl<unsigned> & Params)4553  static bool hasSimilarParameters(ASTContext &Context,
4554                                       FunctionDecl *Declaration,
4555                                       FunctionDecl *Definition,
4556                                       SmallVectorImpl<unsigned> &Params) {
4557    Params.clear();
4558    if (Declaration->param_size() != Definition->param_size())
4559      return false;
4560    for (unsigned Idx = 0; Idx < Declaration->param_size(); ++Idx) {
4561      QualType DeclParamTy = Declaration->getParamDecl(Idx)->getType();
4562      QualType DefParamTy = Definition->getParamDecl(Idx)->getType();
4563  
4564      // The parameter types are identical
4565      if (Context.hasSameType(DefParamTy, DeclParamTy))
4566        continue;
4567  
4568      QualType DeclParamBaseTy = getCoreType(DeclParamTy);
4569      QualType DefParamBaseTy = getCoreType(DefParamTy);
4570      const IdentifierInfo *DeclTyName = DeclParamBaseTy.getBaseTypeIdentifier();
4571      const IdentifierInfo *DefTyName = DefParamBaseTy.getBaseTypeIdentifier();
4572  
4573      if (Context.hasSameUnqualifiedType(DeclParamBaseTy, DefParamBaseTy) ||
4574          (DeclTyName && DeclTyName == DefTyName))
4575        Params.push_back(Idx);
4576      else  // The two parameters aren't even close
4577        return false;
4578    }
4579  
4580    return true;
4581  }
4582  
4583  /// NeedsRebuildingInCurrentInstantiation - Checks whether the given
4584  /// declarator needs to be rebuilt in the current instantiation.
4585  /// Any bits of declarator which appear before the name are valid for
4586  /// consideration here.  That's specifically the type in the decl spec
4587  /// and the base type in any member-pointer chunks.
RebuildDeclaratorInCurrentInstantiation(Sema & S,Declarator & D,DeclarationName Name)4588  static bool RebuildDeclaratorInCurrentInstantiation(Sema &S, Declarator &D,
4589                                                      DeclarationName Name) {
4590    // The types we specifically need to rebuild are:
4591    //   - typenames, typeofs, and decltypes
4592    //   - types which will become injected class names
4593    // Of course, we also need to rebuild any type referencing such a
4594    // type.  It's safest to just say "dependent", but we call out a
4595    // few cases here.
4596  
4597    DeclSpec &DS = D.getMutableDeclSpec();
4598    switch (DS.getTypeSpecType()) {
4599    case DeclSpec::TST_typename:
4600    case DeclSpec::TST_typeofType:
4601    case DeclSpec::TST_underlyingType:
4602    case DeclSpec::TST_atomic: {
4603      // Grab the type from the parser.
4604      TypeSourceInfo *TSI = nullptr;
4605      QualType T = S.GetTypeFromParser(DS.getRepAsType(), &TSI);
4606      if (T.isNull() || !T->isDependentType()) break;
4607  
4608      // Make sure there's a type source info.  This isn't really much
4609      // of a waste; most dependent types should have type source info
4610      // attached already.
4611      if (!TSI)
4612        TSI = S.Context.getTrivialTypeSourceInfo(T, DS.getTypeSpecTypeLoc());
4613  
4614      // Rebuild the type in the current instantiation.
4615      TSI = S.RebuildTypeInCurrentInstantiation(TSI, D.getIdentifierLoc(), Name);
4616      if (!TSI) return true;
4617  
4618      // Store the new type back in the decl spec.
4619      ParsedType LocType = S.CreateParsedType(TSI->getType(), TSI);
4620      DS.UpdateTypeRep(LocType);
4621      break;
4622    }
4623  
4624    case DeclSpec::TST_decltype:
4625    case DeclSpec::TST_typeofExpr: {
4626      Expr *E = DS.getRepAsExpr();
4627      ExprResult Result = S.RebuildExprInCurrentInstantiation(E);
4628      if (Result.isInvalid()) return true;
4629      DS.UpdateExprRep(Result.get());
4630      break;
4631    }
4632  
4633    default:
4634      // Nothing to do for these decl specs.
4635      break;
4636    }
4637  
4638    // It doesn't matter what order we do this in.
4639    for (unsigned I = 0, E = D.getNumTypeObjects(); I != E; ++I) {
4640      DeclaratorChunk &Chunk = D.getTypeObject(I);
4641  
4642      // The only type information in the declarator which can come
4643      // before the declaration name is the base type of a member
4644      // pointer.
4645      if (Chunk.Kind != DeclaratorChunk::MemberPointer)
4646        continue;
4647  
4648      // Rebuild the scope specifier in-place.
4649      CXXScopeSpec &SS = Chunk.Mem.Scope();
4650      if (S.RebuildNestedNameSpecifierInCurrentInstantiation(SS))
4651        return true;
4652    }
4653  
4654    return false;
4655  }
4656  
ActOnDeclarator(Scope * S,Declarator & D)4657  Decl *Sema::ActOnDeclarator(Scope *S, Declarator &D) {
4658    D.setFunctionDefinitionKind(FDK_Declaration);
4659    Decl *Dcl = HandleDeclarator(S, D, MultiTemplateParamsArg());
4660  
4661    if (OriginalLexicalContext && OriginalLexicalContext->isObjCContainer() &&
4662        Dcl && Dcl->getDeclContext()->isFileContext())
4663      Dcl->setTopLevelDeclInObjCContainer();
4664  
4665    return Dcl;
4666  }
4667  
4668  /// DiagnoseClassNameShadow - Implement C++ [class.mem]p13:
4669  ///   If T is the name of a class, then each of the following shall have a
4670  ///   name different from T:
4671  ///     - every static data member of class T;
4672  ///     - every member function of class T
4673  ///     - every member of class T that is itself a type;
4674  /// \returns true if the declaration name violates these rules.
DiagnoseClassNameShadow(DeclContext * DC,DeclarationNameInfo NameInfo)4675  bool Sema::DiagnoseClassNameShadow(DeclContext *DC,
4676                                     DeclarationNameInfo NameInfo) {
4677    DeclarationName Name = NameInfo.getName();
4678  
4679    if (CXXRecordDecl *Record = dyn_cast<CXXRecordDecl>(DC))
4680      if (Record->getIdentifier() && Record->getDeclName() == Name) {
4681        Diag(NameInfo.getLoc(), diag::err_member_name_of_class) << Name;
4682        return true;
4683      }
4684  
4685    return false;
4686  }
4687  
4688  /// \brief Diagnose a declaration whose declarator-id has the given
4689  /// nested-name-specifier.
4690  ///
4691  /// \param SS The nested-name-specifier of the declarator-id.
4692  ///
4693  /// \param DC The declaration context to which the nested-name-specifier
4694  /// resolves.
4695  ///
4696  /// \param Name The name of the entity being declared.
4697  ///
4698  /// \param Loc The location of the name of the entity being declared.
4699  ///
4700  /// \returns true if we cannot safely recover from this error, false otherwise.
diagnoseQualifiedDeclaration(CXXScopeSpec & SS,DeclContext * DC,DeclarationName Name,SourceLocation Loc)4701  bool Sema::diagnoseQualifiedDeclaration(CXXScopeSpec &SS, DeclContext *DC,
4702                                          DeclarationName Name,
4703                                          SourceLocation Loc) {
4704    DeclContext *Cur = CurContext;
4705    while (isa<LinkageSpecDecl>(Cur) || isa<CapturedDecl>(Cur))
4706      Cur = Cur->getParent();
4707  
4708    // If the user provided a superfluous scope specifier that refers back to the
4709    // class in which the entity is already declared, diagnose and ignore it.
4710    //
4711    // class X {
4712    //   void X::f();
4713    // };
4714    //
4715    // Note, it was once ill-formed to give redundant qualification in all
4716    // contexts, but that rule was removed by DR482.
4717    if (Cur->Equals(DC)) {
4718      if (Cur->isRecord()) {
4719        Diag(Loc, LangOpts.MicrosoftExt ? diag::warn_member_extra_qualification
4720                                        : diag::err_member_extra_qualification)
4721          << Name << FixItHint::CreateRemoval(SS.getRange());
4722        SS.clear();
4723      } else {
4724        Diag(Loc, diag::warn_namespace_member_extra_qualification) << Name;
4725      }
4726      return false;
4727    }
4728  
4729    // Check whether the qualifying scope encloses the scope of the original
4730    // declaration.
4731    if (!Cur->Encloses(DC)) {
4732      if (Cur->isRecord())
4733        Diag(Loc, diag::err_member_qualification)
4734          << Name << SS.getRange();
4735      else if (isa<TranslationUnitDecl>(DC))
4736        Diag(Loc, diag::err_invalid_declarator_global_scope)
4737          << Name << SS.getRange();
4738      else if (isa<FunctionDecl>(Cur))
4739        Diag(Loc, diag::err_invalid_declarator_in_function)
4740          << Name << SS.getRange();
4741      else if (isa<BlockDecl>(Cur))
4742        Diag(Loc, diag::err_invalid_declarator_in_block)
4743          << Name << SS.getRange();
4744      else
4745        Diag(Loc, diag::err_invalid_declarator_scope)
4746        << Name << cast<NamedDecl>(Cur) << cast<NamedDecl>(DC) << SS.getRange();
4747  
4748      return true;
4749    }
4750  
4751    if (Cur->isRecord()) {
4752      // Cannot qualify members within a class.
4753      Diag(Loc, diag::err_member_qualification)
4754        << Name << SS.getRange();
4755      SS.clear();
4756  
4757      // C++ constructors and destructors with incorrect scopes can break
4758      // our AST invariants by having the wrong underlying types. If
4759      // that's the case, then drop this declaration entirely.
4760      if ((Name.getNameKind() == DeclarationName::CXXConstructorName ||
4761           Name.getNameKind() == DeclarationName::CXXDestructorName) &&
4762          !Context.hasSameType(Name.getCXXNameType(),
4763                               Context.getTypeDeclType(cast<CXXRecordDecl>(Cur))))
4764        return true;
4765  
4766      return false;
4767    }
4768  
4769    // C++11 [dcl.meaning]p1:
4770    //   [...] "The nested-name-specifier of the qualified declarator-id shall
4771    //   not begin with a decltype-specifer"
4772    NestedNameSpecifierLoc SpecLoc(SS.getScopeRep(), SS.location_data());
4773    while (SpecLoc.getPrefix())
4774      SpecLoc = SpecLoc.getPrefix();
4775    if (dyn_cast_or_null<DecltypeType>(
4776          SpecLoc.getNestedNameSpecifier()->getAsType()))
4777      Diag(Loc, diag::err_decltype_in_declarator)
4778        << SpecLoc.getTypeLoc().getSourceRange();
4779  
4780    return false;
4781  }
4782  
HandleDeclarator(Scope * S,Declarator & D,MultiTemplateParamsArg TemplateParamLists)4783  NamedDecl *Sema::HandleDeclarator(Scope *S, Declarator &D,
4784                                    MultiTemplateParamsArg TemplateParamLists) {
4785    // TODO: consider using NameInfo for diagnostic.
4786    DeclarationNameInfo NameInfo = GetNameForDeclarator(D);
4787    DeclarationName Name = NameInfo.getName();
4788  
4789    // All of these full declarators require an identifier.  If it doesn't have
4790    // one, the ParsedFreeStandingDeclSpec action should be used.
4791    if (!Name) {
4792      if (!D.isInvalidType())  // Reject this if we think it is valid.
4793        Diag(D.getDeclSpec().getLocStart(),
4794             diag::err_declarator_need_ident)
4795          << D.getDeclSpec().getSourceRange() << D.getSourceRange();
4796      return nullptr;
4797    } else if (DiagnoseUnexpandedParameterPack(NameInfo, UPPC_DeclarationType))
4798      return nullptr;
4799  
4800    // The scope passed in may not be a decl scope.  Zip up the scope tree until
4801    // we find one that is.
4802    while ((S->getFlags() & Scope::DeclScope) == 0 ||
4803           (S->getFlags() & Scope::TemplateParamScope) != 0)
4804      S = S->getParent();
4805  
4806    DeclContext *DC = CurContext;
4807    if (D.getCXXScopeSpec().isInvalid())
4808      D.setInvalidType();
4809    else if (D.getCXXScopeSpec().isSet()) {
4810      if (DiagnoseUnexpandedParameterPack(D.getCXXScopeSpec(),
4811                                          UPPC_DeclarationQualifier))
4812        return nullptr;
4813  
4814      bool EnteringContext = !D.getDeclSpec().isFriendSpecified();
4815      DC = computeDeclContext(D.getCXXScopeSpec(), EnteringContext);
4816      if (!DC || isa<EnumDecl>(DC)) {
4817        // If we could not compute the declaration context, it's because the
4818        // declaration context is dependent but does not refer to a class,
4819        // class template, or class template partial specialization. Complain
4820        // and return early, to avoid the coming semantic disaster.
4821        Diag(D.getIdentifierLoc(),
4822             diag::err_template_qualified_declarator_no_match)
4823          << D.getCXXScopeSpec().getScopeRep()
4824          << D.getCXXScopeSpec().getRange();
4825        return nullptr;
4826      }
4827      bool IsDependentContext = DC->isDependentContext();
4828  
4829      if (!IsDependentContext &&
4830          RequireCompleteDeclContext(D.getCXXScopeSpec(), DC))
4831        return nullptr;
4832  
4833      // If a class is incomplete, do not parse entities inside it.
4834      if (isa<CXXRecordDecl>(DC) && !cast<CXXRecordDecl>(DC)->hasDefinition()) {
4835        Diag(D.getIdentifierLoc(),
4836             diag::err_member_def_undefined_record)
4837          << Name << DC << D.getCXXScopeSpec().getRange();
4838        return nullptr;
4839      }
4840      if (!D.getDeclSpec().isFriendSpecified()) {
4841        if (diagnoseQualifiedDeclaration(D.getCXXScopeSpec(), DC,
4842                                        Name, D.getIdentifierLoc())) {
4843          if (DC->isRecord())
4844            return nullptr;
4845  
4846          D.setInvalidType();
4847        }
4848      }
4849  
4850      // Check whether we need to rebuild the type of the given
4851      // declaration in the current instantiation.
4852      if (EnteringContext && IsDependentContext &&
4853          TemplateParamLists.size() != 0) {
4854        ContextRAII SavedContext(*this, DC);
4855        if (RebuildDeclaratorInCurrentInstantiation(*this, D, Name))
4856          D.setInvalidType();
4857      }
4858    }
4859  
4860    TypeSourceInfo *TInfo = GetTypeForDeclarator(D, S);
4861    QualType R = TInfo->getType();
4862  
4863    if (!R->isFunctionType() && DiagnoseClassNameShadow(DC, NameInfo))
4864      // If this is a typedef, we'll end up spewing multiple diagnostics.
4865      // Just return early; it's safer. If this is a function, let the
4866      // "constructor cannot have a return type" diagnostic handle it.
4867      if (D.getDeclSpec().getStorageClassSpec() == DeclSpec::SCS_typedef)
4868        return nullptr;
4869  
4870    if (DiagnoseUnexpandedParameterPack(D.getIdentifierLoc(), TInfo,
4871                                        UPPC_DeclarationType))
4872      D.setInvalidType();
4873  
4874    LookupResult Previous(*this, NameInfo, LookupOrdinaryName,
4875                          ForRedeclaration);
4876  
4877    // See if this is a redefinition of a variable in the same scope.
4878    if (!D.getCXXScopeSpec().isSet()) {
4879      bool IsLinkageLookup = false;
4880      bool CreateBuiltins = false;
4881  
4882      // If the declaration we're planning to build will be a function
4883      // or object with linkage, then look for another declaration with
4884      // linkage (C99 6.2.2p4-5 and C++ [basic.link]p6).
4885      //
4886      // If the declaration we're planning to build will be declared with
4887      // external linkage in the translation unit, create any builtin with
4888      // the same name.
4889      if (D.getDeclSpec().getStorageClassSpec() == DeclSpec::SCS_typedef)
4890        /* Do nothing*/;
4891      else if (CurContext->isFunctionOrMethod() &&
4892               (D.getDeclSpec().getStorageClassSpec() == DeclSpec::SCS_extern ||
4893                R->isFunctionType())) {
4894        IsLinkageLookup = true;
4895        CreateBuiltins =
4896            CurContext->getEnclosingNamespaceContext()->isTranslationUnit();
4897      } else if (CurContext->getRedeclContext()->isTranslationUnit() &&
4898                 D.getDeclSpec().getStorageClassSpec() != DeclSpec::SCS_static)
4899        CreateBuiltins = true;
4900  
4901      if (IsLinkageLookup)
4902        Previous.clear(LookupRedeclarationWithLinkage);
4903  
4904      LookupName(Previous, S, CreateBuiltins);
4905    } else { // Something like "int foo::x;"
4906      LookupQualifiedName(Previous, DC);
4907  
4908      // C++ [dcl.meaning]p1:
4909      //   When the declarator-id is qualified, the declaration shall refer to a
4910      //  previously declared member of the class or namespace to which the
4911      //  qualifier refers (or, in the case of a namespace, of an element of the
4912      //  inline namespace set of that namespace (7.3.1)) or to a specialization
4913      //  thereof; [...]
4914      //
4915      // Note that we already checked the context above, and that we do not have
4916      // enough information to make sure that Previous contains the declaration
4917      // we want to match. For example, given:
4918      //
4919      //   class X {
4920      //     void f();
4921      //     void f(float);
4922      //   };
4923      //
4924      //   void X::f(int) { } // ill-formed
4925      //
4926      // In this case, Previous will point to the overload set
4927      // containing the two f's declared in X, but neither of them
4928      // matches.
4929  
4930      // C++ [dcl.meaning]p1:
4931      //   [...] the member shall not merely have been introduced by a
4932      //   using-declaration in the scope of the class or namespace nominated by
4933      //   the nested-name-specifier of the declarator-id.
4934      RemoveUsingDecls(Previous);
4935    }
4936  
4937    if (Previous.isSingleResult() &&
4938        Previous.getFoundDecl()->isTemplateParameter()) {
4939      // Maybe we will complain about the shadowed template parameter.
4940      if (!D.isInvalidType())
4941        DiagnoseTemplateParameterShadow(D.getIdentifierLoc(),
4942                                        Previous.getFoundDecl());
4943  
4944      // Just pretend that we didn't see the previous declaration.
4945      Previous.clear();
4946    }
4947  
4948    // In C++, the previous declaration we find might be a tag type
4949    // (class or enum). In this case, the new declaration will hide the
4950    // tag type. Note that this does does not apply if we're declaring a
4951    // typedef (C++ [dcl.typedef]p4).
4952    if (Previous.isSingleTagDecl() &&
4953        D.getDeclSpec().getStorageClassSpec() != DeclSpec::SCS_typedef)
4954      Previous.clear();
4955  
4956    // Check that there are no default arguments other than in the parameters
4957    // of a function declaration (C++ only).
4958    if (getLangOpts().CPlusPlus)
4959      CheckExtraCXXDefaultArguments(D);
4960  
4961    if (D.getDeclSpec().isConceptSpecified()) {
4962      // C++ Concepts TS [dcl.spec.concept]p1: The concept specifier shall be
4963      // applied only to the definition of a function template or variable
4964      // template, declared in namespace scope
4965      if (!TemplateParamLists.size()) {
4966        Diag(D.getDeclSpec().getConceptSpecLoc(),
4967             diag:: err_concept_wrong_decl_kind);
4968        return nullptr;
4969      }
4970  
4971      if (!DC->getRedeclContext()->isFileContext()) {
4972        Diag(D.getIdentifierLoc(),
4973             diag::err_concept_decls_may_only_appear_in_namespace_scope);
4974        return nullptr;
4975      }
4976    }
4977  
4978    NamedDecl *New;
4979  
4980    bool AddToScope = true;
4981    if (D.getDeclSpec().getStorageClassSpec() == DeclSpec::SCS_typedef) {
4982      if (TemplateParamLists.size()) {
4983        Diag(D.getIdentifierLoc(), diag::err_template_typedef);
4984        return nullptr;
4985      }
4986  
4987      New = ActOnTypedefDeclarator(S, D, DC, TInfo, Previous);
4988    } else if (R->isFunctionType()) {
4989      New = ActOnFunctionDeclarator(S, D, DC, TInfo, Previous,
4990                                    TemplateParamLists,
4991                                    AddToScope);
4992    } else {
4993      New = ActOnVariableDeclarator(S, D, DC, TInfo, Previous, TemplateParamLists,
4994                                    AddToScope);
4995    }
4996  
4997    if (!New)
4998      return nullptr;
4999  
5000    // If this has an identifier and is not an invalid redeclaration or
5001    // function template specialization, add it to the scope stack.
5002    if (New->getDeclName() && AddToScope &&
5003         !(D.isRedeclaration() && New->isInvalidDecl())) {
5004      // Only make a locally-scoped extern declaration visible if it is the first
5005      // declaration of this entity. Qualified lookup for such an entity should
5006      // only find this declaration if there is no visible declaration of it.
5007      bool AddToContext = !D.isRedeclaration() || !New->isLocalExternDecl();
5008      PushOnScopeChains(New, S, AddToContext);
5009      if (!AddToContext)
5010        CurContext->addHiddenDecl(New);
5011    }
5012  
5013    return New;
5014  }
5015  
5016  /// Helper method to turn variable array types into constant array
5017  /// types in certain situations which would otherwise be errors (for
5018  /// GCC compatibility).
TryToFixInvalidVariablyModifiedType(QualType T,ASTContext & Context,bool & SizeIsNegative,llvm::APSInt & Oversized)5019  static QualType TryToFixInvalidVariablyModifiedType(QualType T,
5020                                                      ASTContext &Context,
5021                                                      bool &SizeIsNegative,
5022                                                      llvm::APSInt &Oversized) {
5023    // This method tries to turn a variable array into a constant
5024    // array even when the size isn't an ICE.  This is necessary
5025    // for compatibility with code that depends on gcc's buggy
5026    // constant expression folding, like struct {char x[(int)(char*)2];}
5027    SizeIsNegative = false;
5028    Oversized = 0;
5029  
5030    if (T->isDependentType())
5031      return QualType();
5032  
5033    QualifierCollector Qs;
5034    const Type *Ty = Qs.strip(T);
5035  
5036    if (const PointerType* PTy = dyn_cast<PointerType>(Ty)) {
5037      QualType Pointee = PTy->getPointeeType();
5038      QualType FixedType =
5039          TryToFixInvalidVariablyModifiedType(Pointee, Context, SizeIsNegative,
5040                                              Oversized);
5041      if (FixedType.isNull()) return FixedType;
5042      FixedType = Context.getPointerType(FixedType);
5043      return Qs.apply(Context, FixedType);
5044    }
5045    if (const ParenType* PTy = dyn_cast<ParenType>(Ty)) {
5046      QualType Inner = PTy->getInnerType();
5047      QualType FixedType =
5048          TryToFixInvalidVariablyModifiedType(Inner, Context, SizeIsNegative,
5049                                              Oversized);
5050      if (FixedType.isNull()) return FixedType;
5051      FixedType = Context.getParenType(FixedType);
5052      return Qs.apply(Context, FixedType);
5053    }
5054  
5055    const VariableArrayType* VLATy = dyn_cast<VariableArrayType>(T);
5056    if (!VLATy)
5057      return QualType();
5058    // FIXME: We should probably handle this case
5059    if (VLATy->getElementType()->isVariablyModifiedType())
5060      return QualType();
5061  
5062    llvm::APSInt Res;
5063    if (!VLATy->getSizeExpr() ||
5064        !VLATy->getSizeExpr()->EvaluateAsInt(Res, Context))
5065      return QualType();
5066  
5067    // Check whether the array size is negative.
5068    if (Res.isSigned() && Res.isNegative()) {
5069      SizeIsNegative = true;
5070      return QualType();
5071    }
5072  
5073    // Check whether the array is too large to be addressed.
5074    unsigned ActiveSizeBits
5075      = ConstantArrayType::getNumAddressingBits(Context, VLATy->getElementType(),
5076                                                Res);
5077    if (ActiveSizeBits > ConstantArrayType::getMaxSizeBits(Context)) {
5078      Oversized = Res;
5079      return QualType();
5080    }
5081  
5082    return Context.getConstantArrayType(VLATy->getElementType(),
5083                                        Res, ArrayType::Normal, 0);
5084  }
5085  
5086  static void
FixInvalidVariablyModifiedTypeLoc(TypeLoc SrcTL,TypeLoc DstTL)5087  FixInvalidVariablyModifiedTypeLoc(TypeLoc SrcTL, TypeLoc DstTL) {
5088    SrcTL = SrcTL.getUnqualifiedLoc();
5089    DstTL = DstTL.getUnqualifiedLoc();
5090    if (PointerTypeLoc SrcPTL = SrcTL.getAs<PointerTypeLoc>()) {
5091      PointerTypeLoc DstPTL = DstTL.castAs<PointerTypeLoc>();
5092      FixInvalidVariablyModifiedTypeLoc(SrcPTL.getPointeeLoc(),
5093                                        DstPTL.getPointeeLoc());
5094      DstPTL.setStarLoc(SrcPTL.getStarLoc());
5095      return;
5096    }
5097    if (ParenTypeLoc SrcPTL = SrcTL.getAs<ParenTypeLoc>()) {
5098      ParenTypeLoc DstPTL = DstTL.castAs<ParenTypeLoc>();
5099      FixInvalidVariablyModifiedTypeLoc(SrcPTL.getInnerLoc(),
5100                                        DstPTL.getInnerLoc());
5101      DstPTL.setLParenLoc(SrcPTL.getLParenLoc());
5102      DstPTL.setRParenLoc(SrcPTL.getRParenLoc());
5103      return;
5104    }
5105    ArrayTypeLoc SrcATL = SrcTL.castAs<ArrayTypeLoc>();
5106    ArrayTypeLoc DstATL = DstTL.castAs<ArrayTypeLoc>();
5107    TypeLoc SrcElemTL = SrcATL.getElementLoc();
5108    TypeLoc DstElemTL = DstATL.getElementLoc();
5109    DstElemTL.initializeFullCopy(SrcElemTL);
5110    DstATL.setLBracketLoc(SrcATL.getLBracketLoc());
5111    DstATL.setSizeExpr(SrcATL.getSizeExpr());
5112    DstATL.setRBracketLoc(SrcATL.getRBracketLoc());
5113  }
5114  
5115  /// Helper method to turn variable array types into constant array
5116  /// types in certain situations which would otherwise be errors (for
5117  /// GCC compatibility).
5118  static TypeSourceInfo*
TryToFixInvalidVariablyModifiedTypeSourceInfo(TypeSourceInfo * TInfo,ASTContext & Context,bool & SizeIsNegative,llvm::APSInt & Oversized)5119  TryToFixInvalidVariablyModifiedTypeSourceInfo(TypeSourceInfo *TInfo,
5120                                                ASTContext &Context,
5121                                                bool &SizeIsNegative,
5122                                                llvm::APSInt &Oversized) {
5123    QualType FixedTy
5124      = TryToFixInvalidVariablyModifiedType(TInfo->getType(), Context,
5125                                            SizeIsNegative, Oversized);
5126    if (FixedTy.isNull())
5127      return nullptr;
5128    TypeSourceInfo *FixedTInfo = Context.getTrivialTypeSourceInfo(FixedTy);
5129    FixInvalidVariablyModifiedTypeLoc(TInfo->getTypeLoc(),
5130                                      FixedTInfo->getTypeLoc());
5131    return FixedTInfo;
5132  }
5133  
5134  /// \brief Register the given locally-scoped extern "C" declaration so
5135  /// that it can be found later for redeclarations. We include any extern "C"
5136  /// declaration that is not visible in the translation unit here, not just
5137  /// function-scope declarations.
5138  void
RegisterLocallyScopedExternCDecl(NamedDecl * ND,Scope * S)5139  Sema::RegisterLocallyScopedExternCDecl(NamedDecl *ND, Scope *S) {
5140    if (!getLangOpts().CPlusPlus &&
5141        ND->getLexicalDeclContext()->getRedeclContext()->isTranslationUnit())
5142      // Don't need to track declarations in the TU in C.
5143      return;
5144  
5145    // Note that we have a locally-scoped external with this name.
5146    Context.getExternCContextDecl()->makeDeclVisibleInContext(ND);
5147  }
5148  
findLocallyScopedExternCDecl(DeclarationName Name)5149  NamedDecl *Sema::findLocallyScopedExternCDecl(DeclarationName Name) {
5150    // FIXME: We can have multiple results via __attribute__((overloadable)).
5151    auto Result = Context.getExternCContextDecl()->lookup(Name);
5152    return Result.empty() ? nullptr : *Result.begin();
5153  }
5154  
5155  /// \brief Diagnose function specifiers on a declaration of an identifier that
5156  /// does not identify a function.
DiagnoseFunctionSpecifiers(const DeclSpec & DS)5157  void Sema::DiagnoseFunctionSpecifiers(const DeclSpec &DS) {
5158    // FIXME: We should probably indicate the identifier in question to avoid
5159    // confusion for constructs like "inline int a(), b;"
5160    if (DS.isInlineSpecified())
5161      Diag(DS.getInlineSpecLoc(),
5162           diag::err_inline_non_function);
5163  
5164    if (DS.isVirtualSpecified())
5165      Diag(DS.getVirtualSpecLoc(),
5166           diag::err_virtual_non_function);
5167  
5168    if (DS.isExplicitSpecified())
5169      Diag(DS.getExplicitSpecLoc(),
5170           diag::err_explicit_non_function);
5171  
5172    if (DS.isNoreturnSpecified())
5173      Diag(DS.getNoreturnSpecLoc(),
5174           diag::err_noreturn_non_function);
5175  }
5176  
5177  NamedDecl*
ActOnTypedefDeclarator(Scope * S,Declarator & D,DeclContext * DC,TypeSourceInfo * TInfo,LookupResult & Previous)5178  Sema::ActOnTypedefDeclarator(Scope* S, Declarator& D, DeclContext* DC,
5179                               TypeSourceInfo *TInfo, LookupResult &Previous) {
5180    // Typedef declarators cannot be qualified (C++ [dcl.meaning]p1).
5181    if (D.getCXXScopeSpec().isSet()) {
5182      Diag(D.getIdentifierLoc(), diag::err_qualified_typedef_declarator)
5183        << D.getCXXScopeSpec().getRange();
5184      D.setInvalidType();
5185      // Pretend we didn't see the scope specifier.
5186      DC = CurContext;
5187      Previous.clear();
5188    }
5189  
5190    DiagnoseFunctionSpecifiers(D.getDeclSpec());
5191  
5192    if (D.getDeclSpec().isConstexprSpecified())
5193      Diag(D.getDeclSpec().getConstexprSpecLoc(), diag::err_invalid_constexpr)
5194        << 1;
5195    if (D.getDeclSpec().isConceptSpecified())
5196      Diag(D.getDeclSpec().getConceptSpecLoc(),
5197           diag::err_concept_wrong_decl_kind);
5198  
5199    if (D.getName().Kind != UnqualifiedId::IK_Identifier) {
5200      Diag(D.getName().StartLocation, diag::err_typedef_not_identifier)
5201        << D.getName().getSourceRange();
5202      return nullptr;
5203    }
5204  
5205    TypedefDecl *NewTD = ParseTypedefDecl(S, D, TInfo->getType(), TInfo);
5206    if (!NewTD) return nullptr;
5207  
5208    // Handle attributes prior to checking for duplicates in MergeVarDecl
5209    ProcessDeclAttributes(S, NewTD, D);
5210  
5211    CheckTypedefForVariablyModifiedType(S, NewTD);
5212  
5213    bool Redeclaration = D.isRedeclaration();
5214    NamedDecl *ND = ActOnTypedefNameDecl(S, DC, NewTD, Previous, Redeclaration);
5215    D.setRedeclaration(Redeclaration);
5216    return ND;
5217  }
5218  
5219  void
CheckTypedefForVariablyModifiedType(Scope * S,TypedefNameDecl * NewTD)5220  Sema::CheckTypedefForVariablyModifiedType(Scope *S, TypedefNameDecl *NewTD) {
5221    // C99 6.7.7p2: If a typedef name specifies a variably modified type
5222    // then it shall have block scope.
5223    // Note that variably modified types must be fixed before merging the decl so
5224    // that redeclarations will match.
5225    TypeSourceInfo *TInfo = NewTD->getTypeSourceInfo();
5226    QualType T = TInfo->getType();
5227    if (T->isVariablyModifiedType()) {
5228      getCurFunction()->setHasBranchProtectedScope();
5229  
5230      if (S->getFnParent() == nullptr) {
5231        bool SizeIsNegative;
5232        llvm::APSInt Oversized;
5233        TypeSourceInfo *FixedTInfo =
5234          TryToFixInvalidVariablyModifiedTypeSourceInfo(TInfo, Context,
5235                                                        SizeIsNegative,
5236                                                        Oversized);
5237        if (FixedTInfo) {
5238          Diag(NewTD->getLocation(), diag::warn_illegal_constant_array_size);
5239          NewTD->setTypeSourceInfo(FixedTInfo);
5240        } else {
5241          if (SizeIsNegative)
5242            Diag(NewTD->getLocation(), diag::err_typecheck_negative_array_size);
5243          else if (T->isVariableArrayType())
5244            Diag(NewTD->getLocation(), diag::err_vla_decl_in_file_scope);
5245          else if (Oversized.getBoolValue())
5246            Diag(NewTD->getLocation(), diag::err_array_too_large)
5247              << Oversized.toString(10);
5248          else
5249            Diag(NewTD->getLocation(), diag::err_vm_decl_in_file_scope);
5250          NewTD->setInvalidDecl();
5251        }
5252      }
5253    }
5254  }
5255  
5256  
5257  /// ActOnTypedefNameDecl - Perform semantic checking for a declaration which
5258  /// declares a typedef-name, either using the 'typedef' type specifier or via
5259  /// a C++0x [dcl.typedef]p2 alias-declaration: 'using T = A;'.
5260  NamedDecl*
ActOnTypedefNameDecl(Scope * S,DeclContext * DC,TypedefNameDecl * NewTD,LookupResult & Previous,bool & Redeclaration)5261  Sema::ActOnTypedefNameDecl(Scope *S, DeclContext *DC, TypedefNameDecl *NewTD,
5262                             LookupResult &Previous, bool &Redeclaration) {
5263    // Merge the decl with the existing one if appropriate. If the decl is
5264    // in an outer scope, it isn't the same thing.
5265    FilterLookupForScope(Previous, DC, S, /*ConsiderLinkage*/false,
5266                         /*AllowInlineNamespace*/false);
5267    filterNonConflictingPreviousTypedefDecls(*this, NewTD, Previous);
5268    if (!Previous.empty()) {
5269      Redeclaration = true;
5270      MergeTypedefNameDecl(S, NewTD, Previous);
5271    }
5272  
5273    // If this is the C FILE type, notify the AST context.
5274    if (IdentifierInfo *II = NewTD->getIdentifier())
5275      if (!NewTD->isInvalidDecl() &&
5276          NewTD->getDeclContext()->getRedeclContext()->isTranslationUnit()) {
5277        if (II->isStr("FILE"))
5278          Context.setFILEDecl(NewTD);
5279        else if (II->isStr("jmp_buf"))
5280          Context.setjmp_bufDecl(NewTD);
5281        else if (II->isStr("sigjmp_buf"))
5282          Context.setsigjmp_bufDecl(NewTD);
5283        else if (II->isStr("ucontext_t"))
5284          Context.setucontext_tDecl(NewTD);
5285      }
5286  
5287    return NewTD;
5288  }
5289  
5290  /// \brief Determines whether the given declaration is an out-of-scope
5291  /// previous declaration.
5292  ///
5293  /// This routine should be invoked when name lookup has found a
5294  /// previous declaration (PrevDecl) that is not in the scope where a
5295  /// new declaration by the same name is being introduced. If the new
5296  /// declaration occurs in a local scope, previous declarations with
5297  /// linkage may still be considered previous declarations (C99
5298  /// 6.2.2p4-5, C++ [basic.link]p6).
5299  ///
5300  /// \param PrevDecl the previous declaration found by name
5301  /// lookup
5302  ///
5303  /// \param DC the context in which the new declaration is being
5304  /// declared.
5305  ///
5306  /// \returns true if PrevDecl is an out-of-scope previous declaration
5307  /// for a new delcaration with the same name.
5308  static bool
isOutOfScopePreviousDeclaration(NamedDecl * PrevDecl,DeclContext * DC,ASTContext & Context)5309  isOutOfScopePreviousDeclaration(NamedDecl *PrevDecl, DeclContext *DC,
5310                                  ASTContext &Context) {
5311    if (!PrevDecl)
5312      return false;
5313  
5314    if (!PrevDecl->hasLinkage())
5315      return false;
5316  
5317    if (Context.getLangOpts().CPlusPlus) {
5318      // C++ [basic.link]p6:
5319      //   If there is a visible declaration of an entity with linkage
5320      //   having the same name and type, ignoring entities declared
5321      //   outside the innermost enclosing namespace scope, the block
5322      //   scope declaration declares that same entity and receives the
5323      //   linkage of the previous declaration.
5324      DeclContext *OuterContext = DC->getRedeclContext();
5325      if (!OuterContext->isFunctionOrMethod())
5326        // This rule only applies to block-scope declarations.
5327        return false;
5328  
5329      DeclContext *PrevOuterContext = PrevDecl->getDeclContext();
5330      if (PrevOuterContext->isRecord())
5331        // We found a member function: ignore it.
5332        return false;
5333  
5334      // Find the innermost enclosing namespace for the new and
5335      // previous declarations.
5336      OuterContext = OuterContext->getEnclosingNamespaceContext();
5337      PrevOuterContext = PrevOuterContext->getEnclosingNamespaceContext();
5338  
5339      // The previous declaration is in a different namespace, so it
5340      // isn't the same function.
5341      if (!OuterContext->Equals(PrevOuterContext))
5342        return false;
5343    }
5344  
5345    return true;
5346  }
5347  
SetNestedNameSpecifier(DeclaratorDecl * DD,Declarator & D)5348  static void SetNestedNameSpecifier(DeclaratorDecl *DD, Declarator &D) {
5349    CXXScopeSpec &SS = D.getCXXScopeSpec();
5350    if (!SS.isSet()) return;
5351    DD->setQualifierInfo(SS.getWithLocInContext(DD->getASTContext()));
5352  }
5353  
inferObjCARCLifetime(ValueDecl * decl)5354  bool Sema::inferObjCARCLifetime(ValueDecl *decl) {
5355    QualType type = decl->getType();
5356    Qualifiers::ObjCLifetime lifetime = type.getObjCLifetime();
5357    if (lifetime == Qualifiers::OCL_Autoreleasing) {
5358      // Various kinds of declaration aren't allowed to be __autoreleasing.
5359      unsigned kind = -1U;
5360      if (VarDecl *var = dyn_cast<VarDecl>(decl)) {
5361        if (var->hasAttr<BlocksAttr>())
5362          kind = 0; // __block
5363        else if (!var->hasLocalStorage())
5364          kind = 1; // global
5365      } else if (isa<ObjCIvarDecl>(decl)) {
5366        kind = 3; // ivar
5367      } else if (isa<FieldDecl>(decl)) {
5368        kind = 2; // field
5369      }
5370  
5371      if (kind != -1U) {
5372        Diag(decl->getLocation(), diag::err_arc_autoreleasing_var)
5373          << kind;
5374      }
5375    } else if (lifetime == Qualifiers::OCL_None) {
5376      // Try to infer lifetime.
5377      if (!type->isObjCLifetimeType())
5378        return false;
5379  
5380      lifetime = type->getObjCARCImplicitLifetime();
5381      type = Context.getLifetimeQualifiedType(type, lifetime);
5382      decl->setType(type);
5383    }
5384  
5385    if (VarDecl *var = dyn_cast<VarDecl>(decl)) {
5386      // Thread-local variables cannot have lifetime.
5387      if (lifetime && lifetime != Qualifiers::OCL_ExplicitNone &&
5388          var->getTLSKind()) {
5389        Diag(var->getLocation(), diag::err_arc_thread_ownership)
5390          << var->getType();
5391        return true;
5392      }
5393    }
5394  
5395    return false;
5396  }
5397  
checkAttributesAfterMerging(Sema & S,NamedDecl & ND)5398  static void checkAttributesAfterMerging(Sema &S, NamedDecl &ND) {
5399    // Ensure that an auto decl is deduced otherwise the checks below might cache
5400    // the wrong linkage.
5401    assert(S.ParsingInitForAutoVars.count(&ND) == 0);
5402  
5403    // 'weak' only applies to declarations with external linkage.
5404    if (WeakAttr *Attr = ND.getAttr<WeakAttr>()) {
5405      if (!ND.isExternallyVisible()) {
5406        S.Diag(Attr->getLocation(), diag::err_attribute_weak_static);
5407        ND.dropAttr<WeakAttr>();
5408      }
5409    }
5410    if (WeakRefAttr *Attr = ND.getAttr<WeakRefAttr>()) {
5411      if (ND.isExternallyVisible()) {
5412        S.Diag(Attr->getLocation(), diag::err_attribute_weakref_not_static);
5413        ND.dropAttr<WeakRefAttr>();
5414        ND.dropAttr<AliasAttr>();
5415      }
5416    }
5417  
5418    if (auto *VD = dyn_cast<VarDecl>(&ND)) {
5419      if (VD->hasInit()) {
5420        if (const auto *Attr = VD->getAttr<AliasAttr>()) {
5421          assert(VD->isThisDeclarationADefinition() &&
5422                 !VD->isExternallyVisible() && "Broken AliasAttr handled late!");
5423          S.Diag(Attr->getLocation(), diag::err_alias_is_definition) << VD;
5424          VD->dropAttr<AliasAttr>();
5425        }
5426      }
5427    }
5428  
5429    // 'selectany' only applies to externally visible variable declarations.
5430    // It does not apply to functions.
5431    if (SelectAnyAttr *Attr = ND.getAttr<SelectAnyAttr>()) {
5432      if (isa<FunctionDecl>(ND) || !ND.isExternallyVisible()) {
5433        S.Diag(Attr->getLocation(),
5434               diag::err_attribute_selectany_non_extern_data);
5435        ND.dropAttr<SelectAnyAttr>();
5436      }
5437    }
5438  
5439    if (const InheritableAttr *Attr = getDLLAttr(&ND)) {
5440      // dll attributes require external linkage. Static locals may have external
5441      // linkage but still cannot be explicitly imported or exported.
5442      auto *VD = dyn_cast<VarDecl>(&ND);
5443      if (!ND.isExternallyVisible() || (VD && VD->isStaticLocal())) {
5444        S.Diag(ND.getLocation(), diag::err_attribute_dll_not_extern)
5445          << &ND << Attr;
5446        ND.setInvalidDecl();
5447      }
5448    }
5449  
5450    // Virtual functions cannot be marked as 'notail'.
5451    if (auto *Attr = ND.getAttr<NotTailCalledAttr>())
5452      if (auto *MD = dyn_cast<CXXMethodDecl>(&ND))
5453        if (MD->isVirtual()) {
5454          S.Diag(ND.getLocation(),
5455                 diag::err_invalid_attribute_on_virtual_function)
5456              << Attr;
5457          ND.dropAttr<NotTailCalledAttr>();
5458        }
5459  }
5460  
checkDLLAttributeRedeclaration(Sema & S,NamedDecl * OldDecl,NamedDecl * NewDecl,bool IsSpecialization)5461  static void checkDLLAttributeRedeclaration(Sema &S, NamedDecl *OldDecl,
5462                                             NamedDecl *NewDecl,
5463                                             bool IsSpecialization) {
5464    if (TemplateDecl *OldTD = dyn_cast<TemplateDecl>(OldDecl))
5465      OldDecl = OldTD->getTemplatedDecl();
5466    if (TemplateDecl *NewTD = dyn_cast<TemplateDecl>(NewDecl))
5467      NewDecl = NewTD->getTemplatedDecl();
5468  
5469    if (!OldDecl || !NewDecl)
5470      return;
5471  
5472    const DLLImportAttr *OldImportAttr = OldDecl->getAttr<DLLImportAttr>();
5473    const DLLExportAttr *OldExportAttr = OldDecl->getAttr<DLLExportAttr>();
5474    const DLLImportAttr *NewImportAttr = NewDecl->getAttr<DLLImportAttr>();
5475    const DLLExportAttr *NewExportAttr = NewDecl->getAttr<DLLExportAttr>();
5476  
5477    // dllimport and dllexport are inheritable attributes so we have to exclude
5478    // inherited attribute instances.
5479    bool HasNewAttr = (NewImportAttr && !NewImportAttr->isInherited()) ||
5480                      (NewExportAttr && !NewExportAttr->isInherited());
5481  
5482    // A redeclaration is not allowed to add a dllimport or dllexport attribute,
5483    // the only exception being explicit specializations.
5484    // Implicitly generated declarations are also excluded for now because there
5485    // is no other way to switch these to use dllimport or dllexport.
5486    bool AddsAttr = !(OldImportAttr || OldExportAttr) && HasNewAttr;
5487  
5488    if (AddsAttr && !IsSpecialization && !OldDecl->isImplicit()) {
5489      // Allow with a warning for free functions and global variables.
5490      bool JustWarn = false;
5491      if (!OldDecl->isCXXClassMember()) {
5492        auto *VD = dyn_cast<VarDecl>(OldDecl);
5493        if (VD && !VD->getDescribedVarTemplate())
5494          JustWarn = true;
5495        auto *FD = dyn_cast<FunctionDecl>(OldDecl);
5496        if (FD && FD->getTemplatedKind() == FunctionDecl::TK_NonTemplate)
5497          JustWarn = true;
5498      }
5499  
5500      // We cannot change a declaration that's been used because IR has already
5501      // been emitted. Dllimported functions will still work though (modulo
5502      // address equality) as they can use the thunk.
5503      if (OldDecl->isUsed())
5504        if (!isa<FunctionDecl>(OldDecl) || !NewImportAttr)
5505          JustWarn = false;
5506  
5507      unsigned DiagID = JustWarn ? diag::warn_attribute_dll_redeclaration
5508                                 : diag::err_attribute_dll_redeclaration;
5509      S.Diag(NewDecl->getLocation(), DiagID)
5510          << NewDecl
5511          << (NewImportAttr ? (const Attr *)NewImportAttr : NewExportAttr);
5512      S.Diag(OldDecl->getLocation(), diag::note_previous_declaration);
5513      if (!JustWarn) {
5514        NewDecl->setInvalidDecl();
5515        return;
5516      }
5517    }
5518  
5519    // A redeclaration is not allowed to drop a dllimport attribute, the only
5520    // exceptions being inline function definitions, local extern declarations,
5521    // and qualified friend declarations.
5522    // NB: MSVC converts such a declaration to dllexport.
5523    bool IsInline = false, IsStaticDataMember = false, IsQualifiedFriend = false;
5524    if (const auto *VD = dyn_cast<VarDecl>(NewDecl))
5525      // Ignore static data because out-of-line definitions are diagnosed
5526      // separately.
5527      IsStaticDataMember = VD->isStaticDataMember();
5528    else if (const auto *FD = dyn_cast<FunctionDecl>(NewDecl)) {
5529      IsInline = FD->isInlined();
5530      IsQualifiedFriend = FD->getQualifier() &&
5531                          FD->getFriendObjectKind() == Decl::FOK_Declared;
5532    }
5533  
5534    if (OldImportAttr && !HasNewAttr && !IsInline && !IsStaticDataMember &&
5535        !NewDecl->isLocalExternDecl() && !IsQualifiedFriend) {
5536      S.Diag(NewDecl->getLocation(),
5537             diag::warn_redeclaration_without_attribute_prev_attribute_ignored)
5538        << NewDecl << OldImportAttr;
5539      S.Diag(OldDecl->getLocation(), diag::note_previous_declaration);
5540      S.Diag(OldImportAttr->getLocation(), diag::note_previous_attribute);
5541      OldDecl->dropAttr<DLLImportAttr>();
5542      NewDecl->dropAttr<DLLImportAttr>();
5543    } else if (IsInline && OldImportAttr &&
5544               !S.Context.getTargetInfo().getCXXABI().isMicrosoft()) {
5545      // In MinGW, seeing a function declared inline drops the dllimport attribute.
5546      OldDecl->dropAttr<DLLImportAttr>();
5547      NewDecl->dropAttr<DLLImportAttr>();
5548      S.Diag(NewDecl->getLocation(),
5549             diag::warn_dllimport_dropped_from_inline_function)
5550          << NewDecl << OldImportAttr;
5551    }
5552  }
5553  
5554  /// Given that we are within the definition of the given function,
5555  /// will that definition behave like C99's 'inline', where the
5556  /// definition is discarded except for optimization purposes?
isFunctionDefinitionDiscarded(Sema & S,FunctionDecl * FD)5557  static bool isFunctionDefinitionDiscarded(Sema &S, FunctionDecl *FD) {
5558    // Try to avoid calling GetGVALinkageForFunction.
5559  
5560    // All cases of this require the 'inline' keyword.
5561    if (!FD->isInlined()) return false;
5562  
5563    // This is only possible in C++ with the gnu_inline attribute.
5564    if (S.getLangOpts().CPlusPlus && !FD->hasAttr<GNUInlineAttr>())
5565      return false;
5566  
5567    // Okay, go ahead and call the relatively-more-expensive function.
5568  
5569  #ifndef NDEBUG
5570    // AST quite reasonably asserts that it's working on a function
5571    // definition.  We don't really have a way to tell it that we're
5572    // currently defining the function, so just lie to it in +Asserts
5573    // builds.  This is an awful hack.
5574    FD->setLazyBody(1);
5575  #endif
5576  
5577    bool isC99Inline =
5578        S.Context.GetGVALinkageForFunction(FD) == GVA_AvailableExternally;
5579  
5580  #ifndef NDEBUG
5581    FD->setLazyBody(0);
5582  #endif
5583  
5584    return isC99Inline;
5585  }
5586  
5587  /// Determine whether a variable is extern "C" prior to attaching
5588  /// an initializer. We can't just call isExternC() here, because that
5589  /// will also compute and cache whether the declaration is externally
5590  /// visible, which might change when we attach the initializer.
5591  ///
5592  /// This can only be used if the declaration is known to not be a
5593  /// redeclaration of an internal linkage declaration.
5594  ///
5595  /// For instance:
5596  ///
5597  ///   auto x = []{};
5598  ///
5599  /// Attaching the initializer here makes this declaration not externally
5600  /// visible, because its type has internal linkage.
5601  ///
5602  /// FIXME: This is a hack.
5603  template<typename T>
isIncompleteDeclExternC(Sema & S,const T * D)5604  static bool isIncompleteDeclExternC(Sema &S, const T *D) {
5605    if (S.getLangOpts().CPlusPlus) {
5606      // In C++, the overloadable attribute negates the effects of extern "C".
5607      if (!D->isInExternCContext() || D->template hasAttr<OverloadableAttr>())
5608        return false;
5609  
5610      // So do CUDA's host/device attributes if overloading is enabled.
5611      if (S.getLangOpts().CUDA && S.getLangOpts().CUDATargetOverloads &&
5612          (D->template hasAttr<CUDADeviceAttr>() ||
5613           D->template hasAttr<CUDAHostAttr>()))
5614        return false;
5615    }
5616    return D->isExternC();
5617  }
5618  
shouldConsiderLinkage(const VarDecl * VD)5619  static bool shouldConsiderLinkage(const VarDecl *VD) {
5620    const DeclContext *DC = VD->getDeclContext()->getRedeclContext();
5621    if (DC->isFunctionOrMethod())
5622      return VD->hasExternalStorage();
5623    if (DC->isFileContext())
5624      return true;
5625    if (DC->isRecord())
5626      return false;
5627    llvm_unreachable("Unexpected context");
5628  }
5629  
shouldConsiderLinkage(const FunctionDecl * FD)5630  static bool shouldConsiderLinkage(const FunctionDecl *FD) {
5631    const DeclContext *DC = FD->getDeclContext()->getRedeclContext();
5632    if (DC->isFileContext() || DC->isFunctionOrMethod())
5633      return true;
5634    if (DC->isRecord())
5635      return false;
5636    llvm_unreachable("Unexpected context");
5637  }
5638  
hasParsedAttr(Scope * S,const AttributeList * AttrList,AttributeList::Kind Kind)5639  static bool hasParsedAttr(Scope *S, const AttributeList *AttrList,
5640                            AttributeList::Kind Kind) {
5641    for (const AttributeList *L = AttrList; L; L = L->getNext())
5642      if (L->getKind() == Kind)
5643        return true;
5644    return false;
5645  }
5646  
hasParsedAttr(Scope * S,const Declarator & PD,AttributeList::Kind Kind)5647  static bool hasParsedAttr(Scope *S, const Declarator &PD,
5648                            AttributeList::Kind Kind) {
5649    // Check decl attributes on the DeclSpec.
5650    if (hasParsedAttr(S, PD.getDeclSpec().getAttributes().getList(), Kind))
5651      return true;
5652  
5653    // Walk the declarator structure, checking decl attributes that were in a type
5654    // position to the decl itself.
5655    for (unsigned I = 0, E = PD.getNumTypeObjects(); I != E; ++I) {
5656      if (hasParsedAttr(S, PD.getTypeObject(I).getAttrs(), Kind))
5657        return true;
5658    }
5659  
5660    // Finally, check attributes on the decl itself.
5661    return hasParsedAttr(S, PD.getAttributes(), Kind);
5662  }
5663  
5664  /// Adjust the \c DeclContext for a function or variable that might be a
5665  /// function-local external declaration.
adjustContextForLocalExternDecl(DeclContext * & DC)5666  bool Sema::adjustContextForLocalExternDecl(DeclContext *&DC) {
5667    if (!DC->isFunctionOrMethod())
5668      return false;
5669  
5670    // If this is a local extern function or variable declared within a function
5671    // template, don't add it into the enclosing namespace scope until it is
5672    // instantiated; it might have a dependent type right now.
5673    if (DC->isDependentContext())
5674      return true;
5675  
5676    // C++11 [basic.link]p7:
5677    //   When a block scope declaration of an entity with linkage is not found to
5678    //   refer to some other declaration, then that entity is a member of the
5679    //   innermost enclosing namespace.
5680    //
5681    // Per C++11 [namespace.def]p6, the innermost enclosing namespace is a
5682    // semantically-enclosing namespace, not a lexically-enclosing one.
5683    while (!DC->isFileContext() && !isa<LinkageSpecDecl>(DC))
5684      DC = DC->getParent();
5685    return true;
5686  }
5687  
5688  /// \brief Returns true if given declaration has external C language linkage.
isDeclExternC(const Decl * D)5689  static bool isDeclExternC(const Decl *D) {
5690    if (const auto *FD = dyn_cast<FunctionDecl>(D))
5691      return FD->isExternC();
5692    if (const auto *VD = dyn_cast<VarDecl>(D))
5693      return VD->isExternC();
5694  
5695    llvm_unreachable("Unknown type of decl!");
5696  }
5697  
5698  NamedDecl *
ActOnVariableDeclarator(Scope * S,Declarator & D,DeclContext * DC,TypeSourceInfo * TInfo,LookupResult & Previous,MultiTemplateParamsArg TemplateParamLists,bool & AddToScope)5699  Sema::ActOnVariableDeclarator(Scope *S, Declarator &D, DeclContext *DC,
5700                                TypeSourceInfo *TInfo, LookupResult &Previous,
5701                                MultiTemplateParamsArg TemplateParamLists,
5702                                bool &AddToScope) {
5703    QualType R = TInfo->getType();
5704    DeclarationName Name = GetNameForDeclarator(D).getName();
5705  
5706    DeclSpec::SCS SCSpec = D.getDeclSpec().getStorageClassSpec();
5707    StorageClass SC = StorageClassSpecToVarDeclStorageClass(D.getDeclSpec());
5708  
5709    // dllimport globals without explicit storage class are treated as extern. We
5710    // have to change the storage class this early to get the right DeclContext.
5711    if (SC == SC_None && !DC->isRecord() &&
5712        hasParsedAttr(S, D, AttributeList::AT_DLLImport) &&
5713        !hasParsedAttr(S, D, AttributeList::AT_DLLExport))
5714      SC = SC_Extern;
5715  
5716    DeclContext *OriginalDC = DC;
5717    bool IsLocalExternDecl = SC == SC_Extern &&
5718                             adjustContextForLocalExternDecl(DC);
5719  
5720    if (getLangOpts().OpenCL) {
5721      // OpenCL v1.0 s6.8.a.3: Pointers to functions are not allowed.
5722      QualType NR = R;
5723      while (NR->isPointerType()) {
5724        if (NR->isFunctionPointerType()) {
5725          Diag(D.getIdentifierLoc(), diag::err_opencl_function_pointer_variable);
5726          D.setInvalidType();
5727          break;
5728        }
5729        NR = NR->getPointeeType();
5730      }
5731  
5732      if (!getOpenCLOptions().cl_khr_fp16) {
5733        // OpenCL v1.2 s6.1.1.1: reject declaring variables of the half and
5734        // half array type (unless the cl_khr_fp16 extension is enabled).
5735        if (Context.getBaseElementType(R)->isHalfType()) {
5736          Diag(D.getIdentifierLoc(), diag::err_opencl_half_declaration) << R;
5737          D.setInvalidType();
5738        }
5739      }
5740    }
5741  
5742    if (SCSpec == DeclSpec::SCS_mutable) {
5743      // mutable can only appear on non-static class members, so it's always
5744      // an error here
5745      Diag(D.getIdentifierLoc(), diag::err_mutable_nonmember);
5746      D.setInvalidType();
5747      SC = SC_None;
5748    }
5749  
5750    if (getLangOpts().CPlusPlus11 && SCSpec == DeclSpec::SCS_register &&
5751        !D.getAsmLabel() && !getSourceManager().isInSystemMacro(
5752                                D.getDeclSpec().getStorageClassSpecLoc())) {
5753      // In C++11, the 'register' storage class specifier is deprecated.
5754      // Suppress the warning in system macros, it's used in macros in some
5755      // popular C system headers, such as in glibc's htonl() macro.
5756      Diag(D.getDeclSpec().getStorageClassSpecLoc(),
5757           getLangOpts().CPlusPlus1z ? diag::ext_register_storage_class
5758                                     : diag::warn_deprecated_register)
5759        << FixItHint::CreateRemoval(D.getDeclSpec().getStorageClassSpecLoc());
5760    }
5761  
5762    IdentifierInfo *II = Name.getAsIdentifierInfo();
5763    if (!II) {
5764      Diag(D.getIdentifierLoc(), diag::err_bad_variable_name)
5765        << Name;
5766      return nullptr;
5767    }
5768  
5769    DiagnoseFunctionSpecifiers(D.getDeclSpec());
5770  
5771    if (!DC->isRecord() && S->getFnParent() == nullptr) {
5772      // C99 6.9p2: The storage-class specifiers auto and register shall not
5773      // appear in the declaration specifiers in an external declaration.
5774      // Global Register+Asm is a GNU extension we support.
5775      if (SC == SC_Auto || (SC == SC_Register && !D.getAsmLabel())) {
5776        Diag(D.getIdentifierLoc(), diag::err_typecheck_sclass_fscope);
5777        D.setInvalidType();
5778      }
5779    }
5780  
5781    if (getLangOpts().OpenCL) {
5782      // OpenCL v1.2 s6.9.b p4:
5783      // The sampler type cannot be used with the __local and __global address
5784      // space qualifiers.
5785      if (R->isSamplerT() && (R.getAddressSpace() == LangAS::opencl_local ||
5786        R.getAddressSpace() == LangAS::opencl_global)) {
5787        Diag(D.getIdentifierLoc(), diag::err_wrong_sampler_addressspace);
5788      }
5789  
5790      // OpenCL 1.2 spec, p6.9 r:
5791      // The event type cannot be used to declare a program scope variable.
5792      // The event type cannot be used with the __local, __constant and __global
5793      // address space qualifiers.
5794      if (R->isEventT()) {
5795        if (S->getParent() == nullptr) {
5796          Diag(D.getLocStart(), diag::err_event_t_global_var);
5797          D.setInvalidType();
5798        }
5799  
5800        if (R.getAddressSpace()) {
5801          Diag(D.getLocStart(), diag::err_event_t_addr_space_qual);
5802          D.setInvalidType();
5803        }
5804      }
5805    }
5806  
5807    bool IsExplicitSpecialization = false;
5808    bool IsVariableTemplateSpecialization = false;
5809    bool IsPartialSpecialization = false;
5810    bool IsVariableTemplate = false;
5811    VarDecl *NewVD = nullptr;
5812    VarTemplateDecl *NewTemplate = nullptr;
5813    TemplateParameterList *TemplateParams = nullptr;
5814    if (!getLangOpts().CPlusPlus) {
5815      NewVD = VarDecl::Create(Context, DC, D.getLocStart(),
5816                              D.getIdentifierLoc(), II,
5817                              R, TInfo, SC);
5818  
5819      if (D.getDeclSpec().containsPlaceholderType() && R->getContainedAutoType())
5820        ParsingInitForAutoVars.insert(NewVD);
5821  
5822      if (D.isInvalidType())
5823        NewVD->setInvalidDecl();
5824    } else {
5825      bool Invalid = false;
5826  
5827      if (DC->isRecord() && !CurContext->isRecord()) {
5828        // This is an out-of-line definition of a static data member.
5829        switch (SC) {
5830        case SC_None:
5831          break;
5832        case SC_Static:
5833          Diag(D.getDeclSpec().getStorageClassSpecLoc(),
5834               diag::err_static_out_of_line)
5835            << FixItHint::CreateRemoval(D.getDeclSpec().getStorageClassSpecLoc());
5836          break;
5837        case SC_Auto:
5838        case SC_Register:
5839        case SC_Extern:
5840          // [dcl.stc] p2: The auto or register specifiers shall be applied only
5841          // to names of variables declared in a block or to function parameters.
5842          // [dcl.stc] p6: The extern specifier cannot be used in the declaration
5843          // of class members
5844  
5845          Diag(D.getDeclSpec().getStorageClassSpecLoc(),
5846               diag::err_storage_class_for_static_member)
5847            << FixItHint::CreateRemoval(D.getDeclSpec().getStorageClassSpecLoc());
5848          break;
5849        case SC_PrivateExtern:
5850          llvm_unreachable("C storage class in c++!");
5851        }
5852      }
5853  
5854      if (SC == SC_Static && CurContext->isRecord()) {
5855        if (const CXXRecordDecl *RD = dyn_cast<CXXRecordDecl>(DC)) {
5856          if (RD->isLocalClass())
5857            Diag(D.getIdentifierLoc(),
5858                 diag::err_static_data_member_not_allowed_in_local_class)
5859              << Name << RD->getDeclName();
5860  
5861          // C++98 [class.union]p1: If a union contains a static data member,
5862          // the program is ill-formed. C++11 drops this restriction.
5863          if (RD->isUnion())
5864            Diag(D.getIdentifierLoc(),
5865                 getLangOpts().CPlusPlus11
5866                   ? diag::warn_cxx98_compat_static_data_member_in_union
5867                   : diag::ext_static_data_member_in_union) << Name;
5868          // We conservatively disallow static data members in anonymous structs.
5869          else if (!RD->getDeclName())
5870            Diag(D.getIdentifierLoc(),
5871                 diag::err_static_data_member_not_allowed_in_anon_struct)
5872              << Name << RD->isUnion();
5873        }
5874      }
5875  
5876      // Match up the template parameter lists with the scope specifier, then
5877      // determine whether we have a template or a template specialization.
5878      TemplateParams = MatchTemplateParametersToScopeSpecifier(
5879          D.getDeclSpec().getLocStart(), D.getIdentifierLoc(),
5880          D.getCXXScopeSpec(),
5881          D.getName().getKind() == UnqualifiedId::IK_TemplateId
5882              ? D.getName().TemplateId
5883              : nullptr,
5884          TemplateParamLists,
5885          /*never a friend*/ false, IsExplicitSpecialization, Invalid);
5886  
5887      if (TemplateParams) {
5888        if (!TemplateParams->size() &&
5889            D.getName().getKind() != UnqualifiedId::IK_TemplateId) {
5890          // There is an extraneous 'template<>' for this variable. Complain
5891          // about it, but allow the declaration of the variable.
5892          Diag(TemplateParams->getTemplateLoc(),
5893               diag::err_template_variable_noparams)
5894            << II
5895            << SourceRange(TemplateParams->getTemplateLoc(),
5896                           TemplateParams->getRAngleLoc());
5897          TemplateParams = nullptr;
5898        } else {
5899          if (D.getName().getKind() == UnqualifiedId::IK_TemplateId) {
5900            // This is an explicit specialization or a partial specialization.
5901            // FIXME: Check that we can declare a specialization here.
5902            IsVariableTemplateSpecialization = true;
5903            IsPartialSpecialization = TemplateParams->size() > 0;
5904          } else { // if (TemplateParams->size() > 0)
5905            // This is a template declaration.
5906            IsVariableTemplate = true;
5907  
5908            // Check that we can declare a template here.
5909            if (CheckTemplateDeclScope(S, TemplateParams))
5910              return nullptr;
5911  
5912            // Only C++1y supports variable templates (N3651).
5913            Diag(D.getIdentifierLoc(),
5914                 getLangOpts().CPlusPlus14
5915                     ? diag::warn_cxx11_compat_variable_template
5916                     : diag::ext_variable_template);
5917          }
5918        }
5919      } else {
5920        assert(
5921            (Invalid || D.getName().getKind() != UnqualifiedId::IK_TemplateId) &&
5922            "should have a 'template<>' for this decl");
5923      }
5924  
5925      if (IsVariableTemplateSpecialization) {
5926        SourceLocation TemplateKWLoc =
5927            TemplateParamLists.size() > 0
5928                ? TemplateParamLists[0]->getTemplateLoc()
5929                : SourceLocation();
5930        DeclResult Res = ActOnVarTemplateSpecialization(
5931            S, D, TInfo, TemplateKWLoc, TemplateParams, SC,
5932            IsPartialSpecialization);
5933        if (Res.isInvalid())
5934          return nullptr;
5935        NewVD = cast<VarDecl>(Res.get());
5936        AddToScope = false;
5937      } else
5938        NewVD = VarDecl::Create(Context, DC, D.getLocStart(),
5939                                D.getIdentifierLoc(), II, R, TInfo, SC);
5940  
5941      // If this is supposed to be a variable template, create it as such.
5942      if (IsVariableTemplate) {
5943        NewTemplate =
5944            VarTemplateDecl::Create(Context, DC, D.getIdentifierLoc(), Name,
5945                                    TemplateParams, NewVD);
5946        NewVD->setDescribedVarTemplate(NewTemplate);
5947      }
5948  
5949      // If this decl has an auto type in need of deduction, make a note of the
5950      // Decl so we can diagnose uses of it in its own initializer.
5951      if (D.getDeclSpec().containsPlaceholderType() && R->getContainedAutoType())
5952        ParsingInitForAutoVars.insert(NewVD);
5953  
5954      if (D.isInvalidType() || Invalid) {
5955        NewVD->setInvalidDecl();
5956        if (NewTemplate)
5957          NewTemplate->setInvalidDecl();
5958      }
5959  
5960      SetNestedNameSpecifier(NewVD, D);
5961  
5962      // If we have any template parameter lists that don't directly belong to
5963      // the variable (matching the scope specifier), store them.
5964      unsigned VDTemplateParamLists = TemplateParams ? 1 : 0;
5965      if (TemplateParamLists.size() > VDTemplateParamLists)
5966        NewVD->setTemplateParameterListsInfo(
5967            Context, TemplateParamLists.drop_back(VDTemplateParamLists));
5968  
5969      if (D.getDeclSpec().isConstexprSpecified())
5970        NewVD->setConstexpr(true);
5971  
5972      if (D.getDeclSpec().isConceptSpecified()) {
5973        NewVD->setConcept(true);
5974  
5975        // C++ Concepts TS [dcl.spec.concept]p2: A concept definition shall not
5976        // be declared with the thread_local, inline, friend, or constexpr
5977        // specifiers, [...]
5978        if (D.getDeclSpec().getThreadStorageClassSpec() == TSCS_thread_local) {
5979          Diag(D.getDeclSpec().getThreadStorageClassSpecLoc(),
5980               diag::err_concept_decl_invalid_specifiers)
5981              << 0 << 0;
5982          NewVD->setInvalidDecl(true);
5983        }
5984  
5985        if (D.getDeclSpec().isConstexprSpecified()) {
5986          Diag(D.getDeclSpec().getConstexprSpecLoc(),
5987               diag::err_concept_decl_invalid_specifiers)
5988              << 0 << 3;
5989          NewVD->setInvalidDecl(true);
5990        }
5991      }
5992    }
5993  
5994    // Set the lexical context. If the declarator has a C++ scope specifier, the
5995    // lexical context will be different from the semantic context.
5996    NewVD->setLexicalDeclContext(CurContext);
5997    if (NewTemplate)
5998      NewTemplate->setLexicalDeclContext(CurContext);
5999  
6000    if (IsLocalExternDecl)
6001      NewVD->setLocalExternDecl();
6002  
6003    bool EmitTLSUnsupportedError = false;
6004    if (DeclSpec::TSCS TSCS = D.getDeclSpec().getThreadStorageClassSpec()) {
6005      // C++11 [dcl.stc]p4:
6006      //   When thread_local is applied to a variable of block scope the
6007      //   storage-class-specifier static is implied if it does not appear
6008      //   explicitly.
6009      // Core issue: 'static' is not implied if the variable is declared
6010      //   'extern'.
6011      if (NewVD->hasLocalStorage() &&
6012          (SCSpec != DeclSpec::SCS_unspecified ||
6013           TSCS != DeclSpec::TSCS_thread_local ||
6014           !DC->isFunctionOrMethod()))
6015        Diag(D.getDeclSpec().getThreadStorageClassSpecLoc(),
6016             diag::err_thread_non_global)
6017          << DeclSpec::getSpecifierName(TSCS);
6018      else if (!Context.getTargetInfo().isTLSSupported()) {
6019        if (getLangOpts().CUDA) {
6020          // Postpone error emission until we've collected attributes required to
6021          // figure out whether it's a host or device variable and whether the
6022          // error should be ignored.
6023          EmitTLSUnsupportedError = true;
6024          // We still need to mark the variable as TLS so it shows up in AST with
6025          // proper storage class for other tools to use even if we're not going
6026          // to emit any code for it.
6027          NewVD->setTSCSpec(TSCS);
6028        } else
6029          Diag(D.getDeclSpec().getThreadStorageClassSpecLoc(),
6030               diag::err_thread_unsupported);
6031      } else
6032        NewVD->setTSCSpec(TSCS);
6033    }
6034  
6035    // C99 6.7.4p3
6036    //   An inline definition of a function with external linkage shall
6037    //   not contain a definition of a modifiable object with static or
6038    //   thread storage duration...
6039    // We only apply this when the function is required to be defined
6040    // elsewhere, i.e. when the function is not 'extern inline'.  Note
6041    // that a local variable with thread storage duration still has to
6042    // be marked 'static'.  Also note that it's possible to get these
6043    // semantics in C++ using __attribute__((gnu_inline)).
6044    if (SC == SC_Static && S->getFnParent() != nullptr &&
6045        !NewVD->getType().isConstQualified()) {
6046      FunctionDecl *CurFD = getCurFunctionDecl();
6047      if (CurFD && isFunctionDefinitionDiscarded(*this, CurFD)) {
6048        Diag(D.getDeclSpec().getStorageClassSpecLoc(),
6049             diag::warn_static_local_in_extern_inline);
6050        MaybeSuggestAddingStaticToDecl(CurFD);
6051      }
6052    }
6053  
6054    if (D.getDeclSpec().isModulePrivateSpecified()) {
6055      if (IsVariableTemplateSpecialization)
6056        Diag(NewVD->getLocation(), diag::err_module_private_specialization)
6057            << (IsPartialSpecialization ? 1 : 0)
6058            << FixItHint::CreateRemoval(
6059                   D.getDeclSpec().getModulePrivateSpecLoc());
6060      else if (IsExplicitSpecialization)
6061        Diag(NewVD->getLocation(), diag::err_module_private_specialization)
6062          << 2
6063          << FixItHint::CreateRemoval(D.getDeclSpec().getModulePrivateSpecLoc());
6064      else if (NewVD->hasLocalStorage())
6065        Diag(NewVD->getLocation(), diag::err_module_private_local)
6066          << 0 << NewVD->getDeclName()
6067          << SourceRange(D.getDeclSpec().getModulePrivateSpecLoc())
6068          << FixItHint::CreateRemoval(D.getDeclSpec().getModulePrivateSpecLoc());
6069      else {
6070        NewVD->setModulePrivate();
6071        if (NewTemplate)
6072          NewTemplate->setModulePrivate();
6073      }
6074    }
6075  
6076    // Handle attributes prior to checking for duplicates in MergeVarDecl
6077    ProcessDeclAttributes(S, NewVD, D);
6078  
6079    if (getLangOpts().CUDA) {
6080      if (EmitTLSUnsupportedError && DeclAttrsMatchCUDAMode(getLangOpts(), NewVD))
6081        Diag(D.getDeclSpec().getThreadStorageClassSpecLoc(),
6082             diag::err_thread_unsupported);
6083      // CUDA B.2.5: "__shared__ and __constant__ variables have implied static
6084      // storage [duration]."
6085      if (SC == SC_None && S->getFnParent() != nullptr &&
6086          (NewVD->hasAttr<CUDASharedAttr>() ||
6087           NewVD->hasAttr<CUDAConstantAttr>())) {
6088        NewVD->setStorageClass(SC_Static);
6089      }
6090    }
6091  
6092    // Ensure that dllimport globals without explicit storage class are treated as
6093    // extern. The storage class is set above using parsed attributes. Now we can
6094    // check the VarDecl itself.
6095    assert(!NewVD->hasAttr<DLLImportAttr>() ||
6096           NewVD->getAttr<DLLImportAttr>()->isInherited() ||
6097           NewVD->isStaticDataMember() || NewVD->getStorageClass() != SC_None);
6098  
6099    // In auto-retain/release, infer strong retension for variables of
6100    // retainable type.
6101    if (getLangOpts().ObjCAutoRefCount && inferObjCARCLifetime(NewVD))
6102      NewVD->setInvalidDecl();
6103  
6104    // Handle GNU asm-label extension (encoded as an attribute).
6105    if (Expr *E = (Expr*)D.getAsmLabel()) {
6106      // The parser guarantees this is a string.
6107      StringLiteral *SE = cast<StringLiteral>(E);
6108      StringRef Label = SE->getString();
6109      if (S->getFnParent() != nullptr) {
6110        switch (SC) {
6111        case SC_None:
6112        case SC_Auto:
6113          Diag(E->getExprLoc(), diag::warn_asm_label_on_auto_decl) << Label;
6114          break;
6115        case SC_Register:
6116          // Local Named register
6117          if (!Context.getTargetInfo().isValidGCCRegisterName(Label) &&
6118              DeclAttrsMatchCUDAMode(getLangOpts(), getCurFunctionDecl()))
6119            Diag(E->getExprLoc(), diag::err_asm_unknown_register_name) << Label;
6120          break;
6121        case SC_Static:
6122        case SC_Extern:
6123        case SC_PrivateExtern:
6124          break;
6125        }
6126      } else if (SC == SC_Register) {
6127        // Global Named register
6128        if (DeclAttrsMatchCUDAMode(getLangOpts(), NewVD)) {
6129          const auto &TI = Context.getTargetInfo();
6130          bool HasSizeMismatch;
6131  
6132          if (!TI.isValidGCCRegisterName(Label))
6133            Diag(E->getExprLoc(), diag::err_asm_unknown_register_name) << Label;
6134          else if (!TI.validateGlobalRegisterVariable(Label,
6135                                                      Context.getTypeSize(R),
6136                                                      HasSizeMismatch))
6137            Diag(E->getExprLoc(), diag::err_asm_invalid_global_var_reg) << Label;
6138          else if (HasSizeMismatch)
6139            Diag(E->getExprLoc(), diag::err_asm_register_size_mismatch) << Label;
6140        }
6141  
6142        if (!R->isIntegralType(Context) && !R->isPointerType()) {
6143          Diag(D.getLocStart(), diag::err_asm_bad_register_type);
6144          NewVD->setInvalidDecl(true);
6145        }
6146      }
6147  
6148      NewVD->addAttr(::new (Context) AsmLabelAttr(SE->getStrTokenLoc(0),
6149                                                  Context, Label, 0));
6150    } else if (!ExtnameUndeclaredIdentifiers.empty()) {
6151      llvm::DenseMap<IdentifierInfo*,AsmLabelAttr*>::iterator I =
6152        ExtnameUndeclaredIdentifiers.find(NewVD->getIdentifier());
6153      if (I != ExtnameUndeclaredIdentifiers.end()) {
6154        if (isDeclExternC(NewVD)) {
6155          NewVD->addAttr(I->second);
6156          ExtnameUndeclaredIdentifiers.erase(I);
6157        } else
6158          Diag(NewVD->getLocation(), diag::warn_redefine_extname_not_applied)
6159              << /*Variable*/1 << NewVD;
6160      }
6161    }
6162  
6163    // Diagnose shadowed variables before filtering for scope.
6164    if (D.getCXXScopeSpec().isEmpty())
6165      CheckShadow(S, NewVD, Previous);
6166  
6167    // Don't consider existing declarations that are in a different
6168    // scope and are out-of-semantic-context declarations (if the new
6169    // declaration has linkage).
6170    FilterLookupForScope(Previous, OriginalDC, S, shouldConsiderLinkage(NewVD),
6171                         D.getCXXScopeSpec().isNotEmpty() ||
6172                         IsExplicitSpecialization ||
6173                         IsVariableTemplateSpecialization);
6174  
6175    // Check whether the previous declaration is in the same block scope. This
6176    // affects whether we merge types with it, per C++11 [dcl.array]p3.
6177    if (getLangOpts().CPlusPlus &&
6178        NewVD->isLocalVarDecl() && NewVD->hasExternalStorage())
6179      NewVD->setPreviousDeclInSameBlockScope(
6180          Previous.isSingleResult() && !Previous.isShadowed() &&
6181          isDeclInScope(Previous.getFoundDecl(), OriginalDC, S, false));
6182  
6183    if (!getLangOpts().CPlusPlus) {
6184      D.setRedeclaration(CheckVariableDeclaration(NewVD, Previous));
6185    } else {
6186      // If this is an explicit specialization of a static data member, check it.
6187      if (IsExplicitSpecialization && !NewVD->isInvalidDecl() &&
6188          CheckMemberSpecialization(NewVD, Previous))
6189        NewVD->setInvalidDecl();
6190  
6191      // Merge the decl with the existing one if appropriate.
6192      if (!Previous.empty()) {
6193        if (Previous.isSingleResult() &&
6194            isa<FieldDecl>(Previous.getFoundDecl()) &&
6195            D.getCXXScopeSpec().isSet()) {
6196          // The user tried to define a non-static data member
6197          // out-of-line (C++ [dcl.meaning]p1).
6198          Diag(NewVD->getLocation(), diag::err_nonstatic_member_out_of_line)
6199            << D.getCXXScopeSpec().getRange();
6200          Previous.clear();
6201          NewVD->setInvalidDecl();
6202        }
6203      } else if (D.getCXXScopeSpec().isSet()) {
6204        // No previous declaration in the qualifying scope.
6205        Diag(D.getIdentifierLoc(), diag::err_no_member)
6206          << Name << computeDeclContext(D.getCXXScopeSpec(), true)
6207          << D.getCXXScopeSpec().getRange();
6208        NewVD->setInvalidDecl();
6209      }
6210  
6211      if (!IsVariableTemplateSpecialization)
6212        D.setRedeclaration(CheckVariableDeclaration(NewVD, Previous));
6213  
6214      if (NewTemplate) {
6215        VarTemplateDecl *PrevVarTemplate =
6216            NewVD->getPreviousDecl()
6217                ? NewVD->getPreviousDecl()->getDescribedVarTemplate()
6218                : nullptr;
6219  
6220        // Check the template parameter list of this declaration, possibly
6221        // merging in the template parameter list from the previous variable
6222        // template declaration.
6223        if (CheckTemplateParameterList(
6224                TemplateParams,
6225                PrevVarTemplate ? PrevVarTemplate->getTemplateParameters()
6226                                : nullptr,
6227                (D.getCXXScopeSpec().isSet() && DC && DC->isRecord() &&
6228                 DC->isDependentContext())
6229                    ? TPC_ClassTemplateMember
6230                    : TPC_VarTemplate))
6231          NewVD->setInvalidDecl();
6232  
6233        // If we are providing an explicit specialization of a static variable
6234        // template, make a note of that.
6235        if (PrevVarTemplate &&
6236            PrevVarTemplate->getInstantiatedFromMemberTemplate())
6237          PrevVarTemplate->setMemberSpecialization();
6238      }
6239    }
6240  
6241    ProcessPragmaWeak(S, NewVD);
6242  
6243    // If this is the first declaration of an extern C variable, update
6244    // the map of such variables.
6245    if (NewVD->isFirstDecl() && !NewVD->isInvalidDecl() &&
6246        isIncompleteDeclExternC(*this, NewVD))
6247      RegisterLocallyScopedExternCDecl(NewVD, S);
6248  
6249    if (getLangOpts().CPlusPlus && NewVD->isStaticLocal()) {
6250      Decl *ManglingContextDecl;
6251      if (MangleNumberingContext *MCtx = getCurrentMangleNumberContext(
6252              NewVD->getDeclContext(), ManglingContextDecl)) {
6253        Context.setManglingNumber(
6254            NewVD, MCtx->getManglingNumber(
6255                       NewVD, getMSManglingNumber(getLangOpts(), S)));
6256        Context.setStaticLocalNumber(NewVD, MCtx->getStaticLocalNumber(NewVD));
6257      }
6258    }
6259  
6260    // Special handling of variable named 'main'.
6261    if (Name.isIdentifier() && Name.getAsIdentifierInfo()->isStr("main") &&
6262        NewVD->getDeclContext()->getRedeclContext()->isTranslationUnit() &&
6263        !getLangOpts().Freestanding && !NewVD->getDescribedVarTemplate()) {
6264  
6265      // C++ [basic.start.main]p3
6266      // A program that declares a variable main at global scope is ill-formed.
6267      if (getLangOpts().CPlusPlus)
6268        Diag(D.getLocStart(), diag::err_main_global_variable);
6269  
6270      // In C, and external-linkage variable named main results in undefined
6271      // behavior.
6272      else if (NewVD->hasExternalFormalLinkage())
6273        Diag(D.getLocStart(), diag::warn_main_redefined);
6274    }
6275  
6276    if (D.isRedeclaration() && !Previous.empty()) {
6277      checkDLLAttributeRedeclaration(
6278          *this, dyn_cast<NamedDecl>(Previous.getRepresentativeDecl()), NewVD,
6279          IsExplicitSpecialization);
6280    }
6281  
6282    if (NewTemplate) {
6283      if (NewVD->isInvalidDecl())
6284        NewTemplate->setInvalidDecl();
6285      ActOnDocumentableDecl(NewTemplate);
6286      return NewTemplate;
6287    }
6288  
6289    return NewVD;
6290  }
6291  
6292  /// \brief Diagnose variable or built-in function shadowing.  Implements
6293  /// -Wshadow.
6294  ///
6295  /// This method is called whenever a VarDecl is added to a "useful"
6296  /// scope.
6297  ///
6298  /// \param S the scope in which the shadowing name is being declared
6299  /// \param R the lookup of the name
6300  ///
CheckShadow(Scope * S,VarDecl * D,const LookupResult & R)6301  void Sema::CheckShadow(Scope *S, VarDecl *D, const LookupResult& R) {
6302    // Return if warning is ignored.
6303    if (Diags.isIgnored(diag::warn_decl_shadow, R.getNameLoc()))
6304      return;
6305  
6306    // Don't diagnose declarations at file scope.
6307    if (D->hasGlobalStorage())
6308      return;
6309  
6310    DeclContext *NewDC = D->getDeclContext();
6311  
6312    // Only diagnose if we're shadowing an unambiguous field or variable.
6313    if (R.getResultKind() != LookupResult::Found)
6314      return;
6315  
6316    NamedDecl* ShadowedDecl = R.getFoundDecl();
6317    if (!isa<VarDecl>(ShadowedDecl) && !isa<FieldDecl>(ShadowedDecl))
6318      return;
6319  
6320    // Fields are not shadowed by variables in C++ static methods.
6321    if (isa<FieldDecl>(ShadowedDecl))
6322      if (CXXMethodDecl *MD = dyn_cast<CXXMethodDecl>(NewDC))
6323        if (MD->isStatic())
6324          return;
6325  
6326    if (VarDecl *shadowedVar = dyn_cast<VarDecl>(ShadowedDecl))
6327      if (shadowedVar->isExternC()) {
6328        // For shadowing external vars, make sure that we point to the global
6329        // declaration, not a locally scoped extern declaration.
6330        for (auto I : shadowedVar->redecls())
6331          if (I->isFileVarDecl()) {
6332            ShadowedDecl = I;
6333            break;
6334          }
6335      }
6336  
6337    DeclContext *OldDC = ShadowedDecl->getDeclContext();
6338  
6339    // Only warn about certain kinds of shadowing for class members.
6340    if (NewDC && NewDC->isRecord()) {
6341      // In particular, don't warn about shadowing non-class members.
6342      if (!OldDC->isRecord())
6343        return;
6344  
6345      // TODO: should we warn about static data members shadowing
6346      // static data members from base classes?
6347  
6348      // TODO: don't diagnose for inaccessible shadowed members.
6349      // This is hard to do perfectly because we might friend the
6350      // shadowing context, but that's just a false negative.
6351    }
6352  
6353    // Determine what kind of declaration we're shadowing.
6354    unsigned Kind;
6355    if (isa<RecordDecl>(OldDC)) {
6356      if (isa<FieldDecl>(ShadowedDecl))
6357        Kind = 3; // field
6358      else
6359        Kind = 2; // static data member
6360    } else if (OldDC->isFileContext())
6361      Kind = 1; // global
6362    else
6363      Kind = 0; // local
6364  
6365    DeclarationName Name = R.getLookupName();
6366  
6367    // Emit warning and note.
6368    if (getSourceManager().isInSystemMacro(R.getNameLoc()))
6369      return;
6370    Diag(R.getNameLoc(), diag::warn_decl_shadow) << Name << Kind << OldDC;
6371    Diag(ShadowedDecl->getLocation(), diag::note_previous_declaration);
6372  }
6373  
6374  /// \brief Check -Wshadow without the advantage of a previous lookup.
CheckShadow(Scope * S,VarDecl * D)6375  void Sema::CheckShadow(Scope *S, VarDecl *D) {
6376    if (Diags.isIgnored(diag::warn_decl_shadow, D->getLocation()))
6377      return;
6378  
6379    LookupResult R(*this, D->getDeclName(), D->getLocation(),
6380                   Sema::LookupOrdinaryName, Sema::ForRedeclaration);
6381    LookupName(R, S);
6382    CheckShadow(S, D, R);
6383  }
6384  
6385  /// Check for conflict between this global or extern "C" declaration and
6386  /// previous global or extern "C" declarations. This is only used in C++.
6387  template<typename T>
checkGlobalOrExternCConflict(Sema & S,const T * ND,bool IsGlobal,LookupResult & Previous)6388  static bool checkGlobalOrExternCConflict(
6389      Sema &S, const T *ND, bool IsGlobal, LookupResult &Previous) {
6390    assert(S.getLangOpts().CPlusPlus && "only C++ has extern \"C\"");
6391    NamedDecl *Prev = S.findLocallyScopedExternCDecl(ND->getDeclName());
6392  
6393    if (!Prev && IsGlobal && !isIncompleteDeclExternC(S, ND)) {
6394      // The common case: this global doesn't conflict with any extern "C"
6395      // declaration.
6396      return false;
6397    }
6398  
6399    if (Prev) {
6400      if (!IsGlobal || isIncompleteDeclExternC(S, ND)) {
6401        // Both the old and new declarations have C language linkage. This is a
6402        // redeclaration.
6403        Previous.clear();
6404        Previous.addDecl(Prev);
6405        return true;
6406      }
6407  
6408      // This is a global, non-extern "C" declaration, and there is a previous
6409      // non-global extern "C" declaration. Diagnose if this is a variable
6410      // declaration.
6411      if (!isa<VarDecl>(ND))
6412        return false;
6413    } else {
6414      // The declaration is extern "C". Check for any declaration in the
6415      // translation unit which might conflict.
6416      if (IsGlobal) {
6417        // We have already performed the lookup into the translation unit.
6418        IsGlobal = false;
6419        for (LookupResult::iterator I = Previous.begin(), E = Previous.end();
6420             I != E; ++I) {
6421          if (isa<VarDecl>(*I)) {
6422            Prev = *I;
6423            break;
6424          }
6425        }
6426      } else {
6427        DeclContext::lookup_result R =
6428            S.Context.getTranslationUnitDecl()->lookup(ND->getDeclName());
6429        for (DeclContext::lookup_result::iterator I = R.begin(), E = R.end();
6430             I != E; ++I) {
6431          if (isa<VarDecl>(*I)) {
6432            Prev = *I;
6433            break;
6434          }
6435          // FIXME: If we have any other entity with this name in global scope,
6436          // the declaration is ill-formed, but that is a defect: it breaks the
6437          // 'stat' hack, for instance. Only variables can have mangled name
6438          // clashes with extern "C" declarations, so only they deserve a
6439          // diagnostic.
6440        }
6441      }
6442  
6443      if (!Prev)
6444        return false;
6445    }
6446  
6447    // Use the first declaration's location to ensure we point at something which
6448    // is lexically inside an extern "C" linkage-spec.
6449    assert(Prev && "should have found a previous declaration to diagnose");
6450    if (FunctionDecl *FD = dyn_cast<FunctionDecl>(Prev))
6451      Prev = FD->getFirstDecl();
6452    else
6453      Prev = cast<VarDecl>(Prev)->getFirstDecl();
6454  
6455    S.Diag(ND->getLocation(), diag::err_extern_c_global_conflict)
6456      << IsGlobal << ND;
6457    S.Diag(Prev->getLocation(), diag::note_extern_c_global_conflict)
6458      << IsGlobal;
6459    return false;
6460  }
6461  
6462  /// Apply special rules for handling extern "C" declarations. Returns \c true
6463  /// if we have found that this is a redeclaration of some prior entity.
6464  ///
6465  /// Per C++ [dcl.link]p6:
6466  ///   Two declarations [for a function or variable] with C language linkage
6467  ///   with the same name that appear in different scopes refer to the same
6468  ///   [entity]. An entity with C language linkage shall not be declared with
6469  ///   the same name as an entity in global scope.
6470  template<typename T>
checkForConflictWithNonVisibleExternC(Sema & S,const T * ND,LookupResult & Previous)6471  static bool checkForConflictWithNonVisibleExternC(Sema &S, const T *ND,
6472                                                    LookupResult &Previous) {
6473    if (!S.getLangOpts().CPlusPlus) {
6474      // In C, when declaring a global variable, look for a corresponding 'extern'
6475      // variable declared in function scope. We don't need this in C++, because
6476      // we find local extern decls in the surrounding file-scope DeclContext.
6477      if (ND->getDeclContext()->getRedeclContext()->isTranslationUnit()) {
6478        if (NamedDecl *Prev = S.findLocallyScopedExternCDecl(ND->getDeclName())) {
6479          Previous.clear();
6480          Previous.addDecl(Prev);
6481          return true;
6482        }
6483      }
6484      return false;
6485    }
6486  
6487    // A declaration in the translation unit can conflict with an extern "C"
6488    // declaration.
6489    if (ND->getDeclContext()->getRedeclContext()->isTranslationUnit())
6490      return checkGlobalOrExternCConflict(S, ND, /*IsGlobal*/true, Previous);
6491  
6492    // An extern "C" declaration can conflict with a declaration in the
6493    // translation unit or can be a redeclaration of an extern "C" declaration
6494    // in another scope.
6495    if (isIncompleteDeclExternC(S,ND))
6496      return checkGlobalOrExternCConflict(S, ND, /*IsGlobal*/false, Previous);
6497  
6498    // Neither global nor extern "C": nothing to do.
6499    return false;
6500  }
6501  
CheckVariableDeclarationType(VarDecl * NewVD)6502  void Sema::CheckVariableDeclarationType(VarDecl *NewVD) {
6503    // If the decl is already known invalid, don't check it.
6504    if (NewVD->isInvalidDecl())
6505      return;
6506  
6507    TypeSourceInfo *TInfo = NewVD->getTypeSourceInfo();
6508    QualType T = TInfo->getType();
6509  
6510    // Defer checking an 'auto' type until its initializer is attached.
6511    if (T->isUndeducedType())
6512      return;
6513  
6514    if (NewVD->hasAttrs())
6515      CheckAlignasUnderalignment(NewVD);
6516  
6517    if (T->isObjCObjectType()) {
6518      Diag(NewVD->getLocation(), diag::err_statically_allocated_object)
6519        << FixItHint::CreateInsertion(NewVD->getLocation(), "*");
6520      T = Context.getObjCObjectPointerType(T);
6521      NewVD->setType(T);
6522    }
6523  
6524    // Emit an error if an address space was applied to decl with local storage.
6525    // This includes arrays of objects with address space qualifiers, but not
6526    // automatic variables that point to other address spaces.
6527    // ISO/IEC TR 18037 S5.1.2
6528    if (!getLangOpts().OpenCL
6529        && NewVD->hasLocalStorage() && T.getAddressSpace() != 0) {
6530      Diag(NewVD->getLocation(), diag::err_as_qualified_auto_decl);
6531      NewVD->setInvalidDecl();
6532      return;
6533    }
6534  
6535    // OpenCL v1.2 s6.8 -- The static qualifier is valid only in program
6536    // scope.
6537    if (getLangOpts().OpenCLVersion == 120 &&
6538        !getOpenCLOptions().cl_clang_storage_class_specifiers &&
6539        NewVD->isStaticLocal()) {
6540      Diag(NewVD->getLocation(), diag::err_static_function_scope);
6541      NewVD->setInvalidDecl();
6542      return;
6543    }
6544  
6545    // OpenCL v1.2 s6.5 - All program scope variables must be declared in the
6546    // __constant address space.
6547    // OpenCL v2.0 s6.5.1 - Variables defined at program scope and static
6548    // variables inside a function can also be declared in the global
6549    // address space.
6550    if (getLangOpts().OpenCL) {
6551      if (NewVD->isFileVarDecl()) {
6552        if (!T->isSamplerT() &&
6553            !(T.getAddressSpace() == LangAS::opencl_constant ||
6554              (T.getAddressSpace() == LangAS::opencl_global &&
6555               getLangOpts().OpenCLVersion == 200))) {
6556          if (getLangOpts().OpenCLVersion == 200)
6557            Diag(NewVD->getLocation(), diag::err_opencl_global_invalid_addr_space)
6558                << "global or constant";
6559          else
6560            Diag(NewVD->getLocation(), diag::err_opencl_global_invalid_addr_space)
6561                << "constant";
6562          NewVD->setInvalidDecl();
6563          return;
6564        }
6565      } else {
6566        // OpenCL v2.0 s6.5.1 - Variables defined at program scope and static
6567        // variables inside a function can also be declared in the global
6568        // address space.
6569        if (NewVD->isStaticLocal() &&
6570            !(T.getAddressSpace() == LangAS::opencl_constant ||
6571              (T.getAddressSpace() == LangAS::opencl_global &&
6572               getLangOpts().OpenCLVersion == 200))) {
6573          if (getLangOpts().OpenCLVersion == 200)
6574            Diag(NewVD->getLocation(), diag::err_opencl_global_invalid_addr_space)
6575                << "global or constant";
6576          else
6577            Diag(NewVD->getLocation(), diag::err_opencl_global_invalid_addr_space)
6578                << "constant";
6579          NewVD->setInvalidDecl();
6580          return;
6581        }
6582        // OpenCL v1.1 s6.5.2 and s6.5.3 no local or constant variables
6583        // in functions.
6584        if (T.getAddressSpace() == LangAS::opencl_constant ||
6585            T.getAddressSpace() == LangAS::opencl_local) {
6586          FunctionDecl *FD = getCurFunctionDecl();
6587          if (FD && !FD->hasAttr<OpenCLKernelAttr>()) {
6588            if (T.getAddressSpace() == LangAS::opencl_constant)
6589              Diag(NewVD->getLocation(), diag::err_opencl_non_kernel_variable)
6590                  << "constant";
6591            else
6592              Diag(NewVD->getLocation(), diag::err_opencl_non_kernel_variable)
6593                  << "local";
6594            NewVD->setInvalidDecl();
6595            return;
6596          }
6597        }
6598      }
6599    }
6600  
6601    if (NewVD->hasLocalStorage() && T.isObjCGCWeak()
6602        && !NewVD->hasAttr<BlocksAttr>()) {
6603      if (getLangOpts().getGC() != LangOptions::NonGC)
6604        Diag(NewVD->getLocation(), diag::warn_gc_attribute_weak_on_local);
6605      else {
6606        assert(!getLangOpts().ObjCAutoRefCount);
6607        Diag(NewVD->getLocation(), diag::warn_attribute_weak_on_local);
6608      }
6609    }
6610  
6611    bool isVM = T->isVariablyModifiedType();
6612    if (isVM || NewVD->hasAttr<CleanupAttr>() ||
6613        NewVD->hasAttr<BlocksAttr>())
6614      getCurFunction()->setHasBranchProtectedScope();
6615  
6616    if ((isVM && NewVD->hasLinkage()) ||
6617        (T->isVariableArrayType() && NewVD->hasGlobalStorage())) {
6618      bool SizeIsNegative;
6619      llvm::APSInt Oversized;
6620      TypeSourceInfo *FixedTInfo =
6621        TryToFixInvalidVariablyModifiedTypeSourceInfo(TInfo, Context,
6622                                                      SizeIsNegative, Oversized);
6623      if (!FixedTInfo && T->isVariableArrayType()) {
6624        const VariableArrayType *VAT = Context.getAsVariableArrayType(T);
6625        // FIXME: This won't give the correct result for
6626        // int a[10][n];
6627        SourceRange SizeRange = VAT->getSizeExpr()->getSourceRange();
6628  
6629        if (NewVD->isFileVarDecl())
6630          Diag(NewVD->getLocation(), diag::err_vla_decl_in_file_scope)
6631          << SizeRange;
6632        else if (NewVD->isStaticLocal())
6633          Diag(NewVD->getLocation(), diag::err_vla_decl_has_static_storage)
6634          << SizeRange;
6635        else
6636          Diag(NewVD->getLocation(), diag::err_vla_decl_has_extern_linkage)
6637          << SizeRange;
6638        NewVD->setInvalidDecl();
6639        return;
6640      }
6641  
6642      if (!FixedTInfo) {
6643        if (NewVD->isFileVarDecl())
6644          Diag(NewVD->getLocation(), diag::err_vm_decl_in_file_scope);
6645        else
6646          Diag(NewVD->getLocation(), diag::err_vm_decl_has_extern_linkage);
6647        NewVD->setInvalidDecl();
6648        return;
6649      }
6650  
6651      Diag(NewVD->getLocation(), diag::warn_illegal_constant_array_size);
6652      NewVD->setType(FixedTInfo->getType());
6653      NewVD->setTypeSourceInfo(FixedTInfo);
6654    }
6655  
6656    if (T->isVoidType()) {
6657      // C++98 [dcl.stc]p5: The extern specifier can be applied only to the names
6658      //                    of objects and functions.
6659      if (NewVD->isThisDeclarationADefinition() || getLangOpts().CPlusPlus) {
6660        Diag(NewVD->getLocation(), diag::err_typecheck_decl_incomplete_type)
6661          << T;
6662        NewVD->setInvalidDecl();
6663        return;
6664      }
6665    }
6666  
6667    if (!NewVD->hasLocalStorage() && NewVD->hasAttr<BlocksAttr>()) {
6668      Diag(NewVD->getLocation(), diag::err_block_on_nonlocal);
6669      NewVD->setInvalidDecl();
6670      return;
6671    }
6672  
6673    if (isVM && NewVD->hasAttr<BlocksAttr>()) {
6674      Diag(NewVD->getLocation(), diag::err_block_on_vm);
6675      NewVD->setInvalidDecl();
6676      return;
6677    }
6678  
6679    if (NewVD->isConstexpr() && !T->isDependentType() &&
6680        RequireLiteralType(NewVD->getLocation(), T,
6681                           diag::err_constexpr_var_non_literal)) {
6682      NewVD->setInvalidDecl();
6683      return;
6684    }
6685  }
6686  
6687  /// \brief Perform semantic checking on a newly-created variable
6688  /// declaration.
6689  ///
6690  /// This routine performs all of the type-checking required for a
6691  /// variable declaration once it has been built. It is used both to
6692  /// check variables after they have been parsed and their declarators
6693  /// have been translated into a declaration, and to check variables
6694  /// that have been instantiated from a template.
6695  ///
6696  /// Sets NewVD->isInvalidDecl() if an error was encountered.
6697  ///
6698  /// Returns true if the variable declaration is a redeclaration.
CheckVariableDeclaration(VarDecl * NewVD,LookupResult & Previous)6699  bool Sema::CheckVariableDeclaration(VarDecl *NewVD, LookupResult &Previous) {
6700    CheckVariableDeclarationType(NewVD);
6701  
6702    // If the decl is already known invalid, don't check it.
6703    if (NewVD->isInvalidDecl())
6704      return false;
6705  
6706    // If we did not find anything by this name, look for a non-visible
6707    // extern "C" declaration with the same name.
6708    if (Previous.empty() &&
6709        checkForConflictWithNonVisibleExternC(*this, NewVD, Previous))
6710      Previous.setShadowed();
6711  
6712    if (!Previous.empty()) {
6713      MergeVarDecl(NewVD, Previous);
6714      return true;
6715    }
6716    return false;
6717  }
6718  
6719  namespace {
6720  struct FindOverriddenMethod {
6721    Sema *S;
6722    CXXMethodDecl *Method;
6723  
6724    /// Member lookup function that determines whether a given C++
6725    /// method overrides a method in a base class, to be used with
6726    /// CXXRecordDecl::lookupInBases().
operator ()__anon7cb36e300511::FindOverriddenMethod6727    bool operator()(const CXXBaseSpecifier *Specifier, CXXBasePath &Path) {
6728      RecordDecl *BaseRecord =
6729          Specifier->getType()->getAs<RecordType>()->getDecl();
6730  
6731      DeclarationName Name = Method->getDeclName();
6732  
6733      // FIXME: Do we care about other names here too?
6734      if (Name.getNameKind() == DeclarationName::CXXDestructorName) {
6735        // We really want to find the base class destructor here.
6736        QualType T = S->Context.getTypeDeclType(BaseRecord);
6737        CanQualType CT = S->Context.getCanonicalType(T);
6738  
6739        Name = S->Context.DeclarationNames.getCXXDestructorName(CT);
6740      }
6741  
6742      for (Path.Decls = BaseRecord->lookup(Name); !Path.Decls.empty();
6743           Path.Decls = Path.Decls.slice(1)) {
6744        NamedDecl *D = Path.Decls.front();
6745        if (CXXMethodDecl *MD = dyn_cast<CXXMethodDecl>(D)) {
6746          if (MD->isVirtual() && !S->IsOverload(Method, MD, false))
6747            return true;
6748        }
6749      }
6750  
6751      return false;
6752    }
6753  };
6754  
6755  enum OverrideErrorKind { OEK_All, OEK_NonDeleted, OEK_Deleted };
6756  } // end anonymous namespace
6757  
6758  /// \brief Report an error regarding overriding, along with any relevant
6759  /// overriden methods.
6760  ///
6761  /// \param DiagID the primary error to report.
6762  /// \param MD the overriding method.
6763  /// \param OEK which overrides to include as notes.
ReportOverrides(Sema & S,unsigned DiagID,const CXXMethodDecl * MD,OverrideErrorKind OEK=OEK_All)6764  static void ReportOverrides(Sema& S, unsigned DiagID, const CXXMethodDecl *MD,
6765                              OverrideErrorKind OEK = OEK_All) {
6766    S.Diag(MD->getLocation(), DiagID) << MD->getDeclName();
6767    for (CXXMethodDecl::method_iterator I = MD->begin_overridden_methods(),
6768                                        E = MD->end_overridden_methods();
6769         I != E; ++I) {
6770      // This check (& the OEK parameter) could be replaced by a predicate, but
6771      // without lambdas that would be overkill. This is still nicer than writing
6772      // out the diag loop 3 times.
6773      if ((OEK == OEK_All) ||
6774          (OEK == OEK_NonDeleted && !(*I)->isDeleted()) ||
6775          (OEK == OEK_Deleted && (*I)->isDeleted()))
6776        S.Diag((*I)->getLocation(), diag::note_overridden_virtual_function);
6777    }
6778  }
6779  
6780  /// AddOverriddenMethods - See if a method overrides any in the base classes,
6781  /// and if so, check that it's a valid override and remember it.
AddOverriddenMethods(CXXRecordDecl * DC,CXXMethodDecl * MD)6782  bool Sema::AddOverriddenMethods(CXXRecordDecl *DC, CXXMethodDecl *MD) {
6783    // Look for methods in base classes that this method might override.
6784    CXXBasePaths Paths;
6785    FindOverriddenMethod FOM;
6786    FOM.Method = MD;
6787    FOM.S = this;
6788    bool hasDeletedOverridenMethods = false;
6789    bool hasNonDeletedOverridenMethods = false;
6790    bool AddedAny = false;
6791    if (DC->lookupInBases(FOM, Paths)) {
6792      for (auto *I : Paths.found_decls()) {
6793        if (CXXMethodDecl *OldMD = dyn_cast<CXXMethodDecl>(I)) {
6794          MD->addOverriddenMethod(OldMD->getCanonicalDecl());
6795          if (!CheckOverridingFunctionReturnType(MD, OldMD) &&
6796              !CheckOverridingFunctionAttributes(MD, OldMD) &&
6797              !CheckOverridingFunctionExceptionSpec(MD, OldMD) &&
6798              !CheckIfOverriddenFunctionIsMarkedFinal(MD, OldMD)) {
6799            hasDeletedOverridenMethods |= OldMD->isDeleted();
6800            hasNonDeletedOverridenMethods |= !OldMD->isDeleted();
6801            AddedAny = true;
6802          }
6803        }
6804      }
6805    }
6806  
6807    if (hasDeletedOverridenMethods && !MD->isDeleted()) {
6808      ReportOverrides(*this, diag::err_non_deleted_override, MD, OEK_Deleted);
6809    }
6810    if (hasNonDeletedOverridenMethods && MD->isDeleted()) {
6811      ReportOverrides(*this, diag::err_deleted_override, MD, OEK_NonDeleted);
6812    }
6813  
6814    return AddedAny;
6815  }
6816  
6817  namespace {
6818    // Struct for holding all of the extra arguments needed by
6819    // DiagnoseInvalidRedeclaration to call Sema::ActOnFunctionDeclarator.
6820    struct ActOnFDArgs {
6821      Scope *S;
6822      Declarator &D;
6823      MultiTemplateParamsArg TemplateParamLists;
6824      bool AddToScope;
6825    };
6826  }
6827  
6828  namespace {
6829  
6830  // Callback to only accept typo corrections that have a non-zero edit distance.
6831  // Also only accept corrections that have the same parent decl.
6832  class DifferentNameValidatorCCC : public CorrectionCandidateCallback {
6833   public:
DifferentNameValidatorCCC(ASTContext & Context,FunctionDecl * TypoFD,CXXRecordDecl * Parent)6834    DifferentNameValidatorCCC(ASTContext &Context, FunctionDecl *TypoFD,
6835                              CXXRecordDecl *Parent)
6836        : Context(Context), OriginalFD(TypoFD),
6837          ExpectedParent(Parent ? Parent->getCanonicalDecl() : nullptr) {}
6838  
ValidateCandidate(const TypoCorrection & candidate)6839    bool ValidateCandidate(const TypoCorrection &candidate) override {
6840      if (candidate.getEditDistance() == 0)
6841        return false;
6842  
6843      SmallVector<unsigned, 1> MismatchedParams;
6844      for (TypoCorrection::const_decl_iterator CDecl = candidate.begin(),
6845                                            CDeclEnd = candidate.end();
6846           CDecl != CDeclEnd; ++CDecl) {
6847        FunctionDecl *FD = dyn_cast<FunctionDecl>(*CDecl);
6848  
6849        if (FD && !FD->hasBody() &&
6850            hasSimilarParameters(Context, FD, OriginalFD, MismatchedParams)) {
6851          if (CXXMethodDecl *MD = dyn_cast<CXXMethodDecl>(FD)) {
6852            CXXRecordDecl *Parent = MD->getParent();
6853            if (Parent && Parent->getCanonicalDecl() == ExpectedParent)
6854              return true;
6855          } else if (!ExpectedParent) {
6856            return true;
6857          }
6858        }
6859      }
6860  
6861      return false;
6862    }
6863  
6864   private:
6865    ASTContext &Context;
6866    FunctionDecl *OriginalFD;
6867    CXXRecordDecl *ExpectedParent;
6868  };
6869  
6870  }
6871  
6872  /// \brief Generate diagnostics for an invalid function redeclaration.
6873  ///
6874  /// This routine handles generating the diagnostic messages for an invalid
6875  /// function redeclaration, including finding possible similar declarations
6876  /// or performing typo correction if there are no previous declarations with
6877  /// the same name.
6878  ///
6879  /// Returns a NamedDecl iff typo correction was performed and substituting in
6880  /// the new declaration name does not cause new errors.
DiagnoseInvalidRedeclaration(Sema & SemaRef,LookupResult & Previous,FunctionDecl * NewFD,ActOnFDArgs & ExtraArgs,bool IsLocalFriend,Scope * S)6881  static NamedDecl *DiagnoseInvalidRedeclaration(
6882      Sema &SemaRef, LookupResult &Previous, FunctionDecl *NewFD,
6883      ActOnFDArgs &ExtraArgs, bool IsLocalFriend, Scope *S) {
6884    DeclarationName Name = NewFD->getDeclName();
6885    DeclContext *NewDC = NewFD->getDeclContext();
6886    SmallVector<unsigned, 1> MismatchedParams;
6887    SmallVector<std::pair<FunctionDecl *, unsigned>, 1> NearMatches;
6888    TypoCorrection Correction;
6889    bool IsDefinition = ExtraArgs.D.isFunctionDefinition();
6890    unsigned DiagMsg = IsLocalFriend ? diag::err_no_matching_local_friend
6891                                     : diag::err_member_decl_does_not_match;
6892    LookupResult Prev(SemaRef, Name, NewFD->getLocation(),
6893                      IsLocalFriend ? Sema::LookupLocalFriendName
6894                                    : Sema::LookupOrdinaryName,
6895                      Sema::ForRedeclaration);
6896  
6897    NewFD->setInvalidDecl();
6898    if (IsLocalFriend)
6899      SemaRef.LookupName(Prev, S);
6900    else
6901      SemaRef.LookupQualifiedName(Prev, NewDC);
6902    assert(!Prev.isAmbiguous() &&
6903           "Cannot have an ambiguity in previous-declaration lookup");
6904    CXXMethodDecl *MD = dyn_cast<CXXMethodDecl>(NewFD);
6905    if (!Prev.empty()) {
6906      for (LookupResult::iterator Func = Prev.begin(), FuncEnd = Prev.end();
6907           Func != FuncEnd; ++Func) {
6908        FunctionDecl *FD = dyn_cast<FunctionDecl>(*Func);
6909        if (FD &&
6910            hasSimilarParameters(SemaRef.Context, FD, NewFD, MismatchedParams)) {
6911          // Add 1 to the index so that 0 can mean the mismatch didn't
6912          // involve a parameter
6913          unsigned ParamNum =
6914              MismatchedParams.empty() ? 0 : MismatchedParams.front() + 1;
6915          NearMatches.push_back(std::make_pair(FD, ParamNum));
6916        }
6917      }
6918    // If the qualified name lookup yielded nothing, try typo correction
6919    } else if ((Correction = SemaRef.CorrectTypo(
6920                    Prev.getLookupNameInfo(), Prev.getLookupKind(), S,
6921                    &ExtraArgs.D.getCXXScopeSpec(),
6922                    llvm::make_unique<DifferentNameValidatorCCC>(
6923                        SemaRef.Context, NewFD, MD ? MD->getParent() : nullptr),
6924                    Sema::CTK_ErrorRecovery, IsLocalFriend ? nullptr : NewDC))) {
6925      // Set up everything for the call to ActOnFunctionDeclarator
6926      ExtraArgs.D.SetIdentifier(Correction.getCorrectionAsIdentifierInfo(),
6927                                ExtraArgs.D.getIdentifierLoc());
6928      Previous.clear();
6929      Previous.setLookupName(Correction.getCorrection());
6930      for (TypoCorrection::decl_iterator CDecl = Correction.begin(),
6931                                      CDeclEnd = Correction.end();
6932           CDecl != CDeclEnd; ++CDecl) {
6933        FunctionDecl *FD = dyn_cast<FunctionDecl>(*CDecl);
6934        if (FD && !FD->hasBody() &&
6935            hasSimilarParameters(SemaRef.Context, FD, NewFD, MismatchedParams)) {
6936          Previous.addDecl(FD);
6937        }
6938      }
6939      bool wasRedeclaration = ExtraArgs.D.isRedeclaration();
6940  
6941      NamedDecl *Result;
6942      // Retry building the function declaration with the new previous
6943      // declarations, and with errors suppressed.
6944      {
6945        // Trap errors.
6946        Sema::SFINAETrap Trap(SemaRef);
6947  
6948        // TODO: Refactor ActOnFunctionDeclarator so that we can call only the
6949        // pieces need to verify the typo-corrected C++ declaration and hopefully
6950        // eliminate the need for the parameter pack ExtraArgs.
6951        Result = SemaRef.ActOnFunctionDeclarator(
6952            ExtraArgs.S, ExtraArgs.D,
6953            Correction.getCorrectionDecl()->getDeclContext(),
6954            NewFD->getTypeSourceInfo(), Previous, ExtraArgs.TemplateParamLists,
6955            ExtraArgs.AddToScope);
6956  
6957        if (Trap.hasErrorOccurred())
6958          Result = nullptr;
6959      }
6960  
6961      if (Result) {
6962        // Determine which correction we picked.
6963        Decl *Canonical = Result->getCanonicalDecl();
6964        for (LookupResult::iterator I = Previous.begin(), E = Previous.end();
6965             I != E; ++I)
6966          if ((*I)->getCanonicalDecl() == Canonical)
6967            Correction.setCorrectionDecl(*I);
6968  
6969        SemaRef.diagnoseTypo(
6970            Correction,
6971            SemaRef.PDiag(IsLocalFriend
6972                            ? diag::err_no_matching_local_friend_suggest
6973                            : diag::err_member_decl_does_not_match_suggest)
6974              << Name << NewDC << IsDefinition);
6975        return Result;
6976      }
6977  
6978      // Pretend the typo correction never occurred
6979      ExtraArgs.D.SetIdentifier(Name.getAsIdentifierInfo(),
6980                                ExtraArgs.D.getIdentifierLoc());
6981      ExtraArgs.D.setRedeclaration(wasRedeclaration);
6982      Previous.clear();
6983      Previous.setLookupName(Name);
6984    }
6985  
6986    SemaRef.Diag(NewFD->getLocation(), DiagMsg)
6987        << Name << NewDC << IsDefinition << NewFD->getLocation();
6988  
6989    bool NewFDisConst = false;
6990    if (CXXMethodDecl *NewMD = dyn_cast<CXXMethodDecl>(NewFD))
6991      NewFDisConst = NewMD->isConst();
6992  
6993    for (SmallVectorImpl<std::pair<FunctionDecl *, unsigned> >::iterator
6994         NearMatch = NearMatches.begin(), NearMatchEnd = NearMatches.end();
6995         NearMatch != NearMatchEnd; ++NearMatch) {
6996      FunctionDecl *FD = NearMatch->first;
6997      CXXMethodDecl *MD = dyn_cast<CXXMethodDecl>(FD);
6998      bool FDisConst = MD && MD->isConst();
6999      bool IsMember = MD || !IsLocalFriend;
7000  
7001      // FIXME: These notes are poorly worded for the local friend case.
7002      if (unsigned Idx = NearMatch->second) {
7003        ParmVarDecl *FDParam = FD->getParamDecl(Idx-1);
7004        SourceLocation Loc = FDParam->getTypeSpecStartLoc();
7005        if (Loc.isInvalid()) Loc = FD->getLocation();
7006        SemaRef.Diag(Loc, IsMember ? diag::note_member_def_close_param_match
7007                                   : diag::note_local_decl_close_param_match)
7008          << Idx << FDParam->getType()
7009          << NewFD->getParamDecl(Idx - 1)->getType();
7010      } else if (FDisConst != NewFDisConst) {
7011        SemaRef.Diag(FD->getLocation(), diag::note_member_def_close_const_match)
7012            << NewFDisConst << FD->getSourceRange().getEnd();
7013      } else
7014        SemaRef.Diag(FD->getLocation(),
7015                     IsMember ? diag::note_member_def_close_match
7016                              : diag::note_local_decl_close_match);
7017    }
7018    return nullptr;
7019  }
7020  
getFunctionStorageClass(Sema & SemaRef,Declarator & D)7021  static StorageClass getFunctionStorageClass(Sema &SemaRef, Declarator &D) {
7022    switch (D.getDeclSpec().getStorageClassSpec()) {
7023    default: llvm_unreachable("Unknown storage class!");
7024    case DeclSpec::SCS_auto:
7025    case DeclSpec::SCS_register:
7026    case DeclSpec::SCS_mutable:
7027      SemaRef.Diag(D.getDeclSpec().getStorageClassSpecLoc(),
7028                   diag::err_typecheck_sclass_func);
7029      D.setInvalidType();
7030      break;
7031    case DeclSpec::SCS_unspecified: break;
7032    case DeclSpec::SCS_extern:
7033      if (D.getDeclSpec().isExternInLinkageSpec())
7034        return SC_None;
7035      return SC_Extern;
7036    case DeclSpec::SCS_static: {
7037      if (SemaRef.CurContext->getRedeclContext()->isFunctionOrMethod()) {
7038        // C99 6.7.1p5:
7039        //   The declaration of an identifier for a function that has
7040        //   block scope shall have no explicit storage-class specifier
7041        //   other than extern
7042        // See also (C++ [dcl.stc]p4).
7043        SemaRef.Diag(D.getDeclSpec().getStorageClassSpecLoc(),
7044                     diag::err_static_block_func);
7045        break;
7046      } else
7047        return SC_Static;
7048    }
7049    case DeclSpec::SCS_private_extern: return SC_PrivateExtern;
7050    }
7051  
7052    // No explicit storage class has already been returned
7053    return SC_None;
7054  }
7055  
CreateNewFunctionDecl(Sema & SemaRef,Declarator & D,DeclContext * DC,QualType & R,TypeSourceInfo * TInfo,StorageClass SC,bool & IsVirtualOkay)7056  static FunctionDecl* CreateNewFunctionDecl(Sema &SemaRef, Declarator &D,
7057                                             DeclContext *DC, QualType &R,
7058                                             TypeSourceInfo *TInfo,
7059                                             StorageClass SC,
7060                                             bool &IsVirtualOkay) {
7061    DeclarationNameInfo NameInfo = SemaRef.GetNameForDeclarator(D);
7062    DeclarationName Name = NameInfo.getName();
7063  
7064    FunctionDecl *NewFD = nullptr;
7065    bool isInline = D.getDeclSpec().isInlineSpecified();
7066  
7067    if (!SemaRef.getLangOpts().CPlusPlus) {
7068      // Determine whether the function was written with a
7069      // prototype. This true when:
7070      //   - there is a prototype in the declarator, or
7071      //   - the type R of the function is some kind of typedef or other reference
7072      //     to a type name (which eventually refers to a function type).
7073      bool HasPrototype =
7074        (D.isFunctionDeclarator() && D.getFunctionTypeInfo().hasPrototype) ||
7075        (!isa<FunctionType>(R.getTypePtr()) && R->isFunctionProtoType());
7076  
7077      NewFD = FunctionDecl::Create(SemaRef.Context, DC,
7078                                   D.getLocStart(), NameInfo, R,
7079                                   TInfo, SC, isInline,
7080                                   HasPrototype, false);
7081      if (D.isInvalidType())
7082        NewFD->setInvalidDecl();
7083  
7084      return NewFD;
7085    }
7086  
7087    bool isExplicit = D.getDeclSpec().isExplicitSpecified();
7088    bool isConstexpr = D.getDeclSpec().isConstexprSpecified();
7089  
7090    // Check that the return type is not an abstract class type.
7091    // For record types, this is done by the AbstractClassUsageDiagnoser once
7092    // the class has been completely parsed.
7093    if (!DC->isRecord() &&
7094        SemaRef.RequireNonAbstractType(
7095            D.getIdentifierLoc(), R->getAs<FunctionType>()->getReturnType(),
7096            diag::err_abstract_type_in_decl, SemaRef.AbstractReturnType))
7097      D.setInvalidType();
7098  
7099    if (Name.getNameKind() == DeclarationName::CXXConstructorName) {
7100      // This is a C++ constructor declaration.
7101      assert(DC->isRecord() &&
7102             "Constructors can only be declared in a member context");
7103  
7104      R = SemaRef.CheckConstructorDeclarator(D, R, SC);
7105      return CXXConstructorDecl::Create(SemaRef.Context, cast<CXXRecordDecl>(DC),
7106                                        D.getLocStart(), NameInfo,
7107                                        R, TInfo, isExplicit, isInline,
7108                                        /*isImplicitlyDeclared=*/false,
7109                                        isConstexpr);
7110  
7111    } else if (Name.getNameKind() == DeclarationName::CXXDestructorName) {
7112      // This is a C++ destructor declaration.
7113      if (DC->isRecord()) {
7114        R = SemaRef.CheckDestructorDeclarator(D, R, SC);
7115        CXXRecordDecl *Record = cast<CXXRecordDecl>(DC);
7116        CXXDestructorDecl *NewDD = CXXDestructorDecl::Create(
7117                                          SemaRef.Context, Record,
7118                                          D.getLocStart(),
7119                                          NameInfo, R, TInfo, isInline,
7120                                          /*isImplicitlyDeclared=*/false);
7121  
7122        // If the class is complete, then we now create the implicit exception
7123        // specification. If the class is incomplete or dependent, we can't do
7124        // it yet.
7125        if (SemaRef.getLangOpts().CPlusPlus11 && !Record->isDependentType() &&
7126            Record->getDefinition() && !Record->isBeingDefined() &&
7127            R->getAs<FunctionProtoType>()->getExceptionSpecType() == EST_None) {
7128          SemaRef.AdjustDestructorExceptionSpec(Record, NewDD);
7129        }
7130  
7131        IsVirtualOkay = true;
7132        return NewDD;
7133  
7134      } else {
7135        SemaRef.Diag(D.getIdentifierLoc(), diag::err_destructor_not_member);
7136        D.setInvalidType();
7137  
7138        // Create a FunctionDecl to satisfy the function definition parsing
7139        // code path.
7140        return FunctionDecl::Create(SemaRef.Context, DC,
7141                                    D.getLocStart(),
7142                                    D.getIdentifierLoc(), Name, R, TInfo,
7143                                    SC, isInline,
7144                                    /*hasPrototype=*/true, isConstexpr);
7145      }
7146  
7147    } else if (Name.getNameKind() == DeclarationName::CXXConversionFunctionName) {
7148      if (!DC->isRecord()) {
7149        SemaRef.Diag(D.getIdentifierLoc(),
7150             diag::err_conv_function_not_member);
7151        return nullptr;
7152      }
7153  
7154      SemaRef.CheckConversionDeclarator(D, R, SC);
7155      IsVirtualOkay = true;
7156      return CXXConversionDecl::Create(SemaRef.Context, cast<CXXRecordDecl>(DC),
7157                                       D.getLocStart(), NameInfo,
7158                                       R, TInfo, isInline, isExplicit,
7159                                       isConstexpr, SourceLocation());
7160  
7161    } else if (DC->isRecord()) {
7162      // If the name of the function is the same as the name of the record,
7163      // then this must be an invalid constructor that has a return type.
7164      // (The parser checks for a return type and makes the declarator a
7165      // constructor if it has no return type).
7166      if (Name.getAsIdentifierInfo() &&
7167          Name.getAsIdentifierInfo() == cast<CXXRecordDecl>(DC)->getIdentifier()){
7168        SemaRef.Diag(D.getIdentifierLoc(), diag::err_constructor_return_type)
7169          << SourceRange(D.getDeclSpec().getTypeSpecTypeLoc())
7170          << SourceRange(D.getIdentifierLoc());
7171        return nullptr;
7172      }
7173  
7174      // This is a C++ method declaration.
7175      CXXMethodDecl *Ret = CXXMethodDecl::Create(SemaRef.Context,
7176                                                 cast<CXXRecordDecl>(DC),
7177                                                 D.getLocStart(), NameInfo, R,
7178                                                 TInfo, SC, isInline,
7179                                                 isConstexpr, SourceLocation());
7180      IsVirtualOkay = !Ret->isStatic();
7181      return Ret;
7182    } else {
7183      bool isFriend =
7184          SemaRef.getLangOpts().CPlusPlus && D.getDeclSpec().isFriendSpecified();
7185      if (!isFriend && SemaRef.CurContext->isRecord())
7186        return nullptr;
7187  
7188      // Determine whether the function was written with a
7189      // prototype. This true when:
7190      //   - we're in C++ (where every function has a prototype),
7191      return FunctionDecl::Create(SemaRef.Context, DC,
7192                                  D.getLocStart(),
7193                                  NameInfo, R, TInfo, SC, isInline,
7194                                  true/*HasPrototype*/, isConstexpr);
7195    }
7196  }
7197  
7198  enum OpenCLParamType {
7199    ValidKernelParam,
7200    PtrPtrKernelParam,
7201    PtrKernelParam,
7202    PrivatePtrKernelParam,
7203    InvalidKernelParam,
7204    RecordKernelParam
7205  };
7206  
getOpenCLKernelParameterType(QualType PT)7207  static OpenCLParamType getOpenCLKernelParameterType(QualType PT) {
7208    if (PT->isPointerType()) {
7209      QualType PointeeType = PT->getPointeeType();
7210      if (PointeeType->isPointerType())
7211        return PtrPtrKernelParam;
7212      return PointeeType.getAddressSpace() == 0 ? PrivatePtrKernelParam
7213                                                : PtrKernelParam;
7214    }
7215  
7216    // TODO: Forbid the other integer types (size_t, ptrdiff_t...) when they can
7217    // be used as builtin types.
7218  
7219    if (PT->isImageType())
7220      return PtrKernelParam;
7221  
7222    if (PT->isBooleanType())
7223      return InvalidKernelParam;
7224  
7225    if (PT->isEventT())
7226      return InvalidKernelParam;
7227  
7228    if (PT->isHalfType())
7229      return InvalidKernelParam;
7230  
7231    if (PT->isRecordType())
7232      return RecordKernelParam;
7233  
7234    return ValidKernelParam;
7235  }
7236  
checkIsValidOpenCLKernelParameter(Sema & S,Declarator & D,ParmVarDecl * Param,llvm::SmallPtrSetImpl<const Type * > & ValidTypes)7237  static void checkIsValidOpenCLKernelParameter(
7238    Sema &S,
7239    Declarator &D,
7240    ParmVarDecl *Param,
7241    llvm::SmallPtrSetImpl<const Type *> &ValidTypes) {
7242    QualType PT = Param->getType();
7243  
7244    // Cache the valid types we encounter to avoid rechecking structs that are
7245    // used again
7246    if (ValidTypes.count(PT.getTypePtr()))
7247      return;
7248  
7249    switch (getOpenCLKernelParameterType(PT)) {
7250    case PtrPtrKernelParam:
7251      // OpenCL v1.2 s6.9.a:
7252      // A kernel function argument cannot be declared as a
7253      // pointer to a pointer type.
7254      S.Diag(Param->getLocation(), diag::err_opencl_ptrptr_kernel_param);
7255      D.setInvalidType();
7256      return;
7257  
7258    case PrivatePtrKernelParam:
7259      // OpenCL v1.2 s6.9.a:
7260      // A kernel function argument cannot be declared as a
7261      // pointer to the private address space.
7262      S.Diag(Param->getLocation(), diag::err_opencl_private_ptr_kernel_param);
7263      D.setInvalidType();
7264      return;
7265  
7266      // OpenCL v1.2 s6.9.k:
7267      // Arguments to kernel functions in a program cannot be declared with the
7268      // built-in scalar types bool, half, size_t, ptrdiff_t, intptr_t, and
7269      // uintptr_t or a struct and/or union that contain fields declared to be
7270      // one of these built-in scalar types.
7271  
7272    case InvalidKernelParam:
7273      // OpenCL v1.2 s6.8 n:
7274      // A kernel function argument cannot be declared
7275      // of event_t type.
7276      S.Diag(Param->getLocation(), diag::err_bad_kernel_param_type) << PT;
7277      D.setInvalidType();
7278      return;
7279  
7280    case PtrKernelParam:
7281    case ValidKernelParam:
7282      ValidTypes.insert(PT.getTypePtr());
7283      return;
7284  
7285    case RecordKernelParam:
7286      break;
7287    }
7288  
7289    // Track nested structs we will inspect
7290    SmallVector<const Decl *, 4> VisitStack;
7291  
7292    // Track where we are in the nested structs. Items will migrate from
7293    // VisitStack to HistoryStack as we do the DFS for bad field.
7294    SmallVector<const FieldDecl *, 4> HistoryStack;
7295    HistoryStack.push_back(nullptr);
7296  
7297    const RecordDecl *PD = PT->castAs<RecordType>()->getDecl();
7298    VisitStack.push_back(PD);
7299  
7300    assert(VisitStack.back() && "First decl null?");
7301  
7302    do {
7303      const Decl *Next = VisitStack.pop_back_val();
7304      if (!Next) {
7305        assert(!HistoryStack.empty());
7306        // Found a marker, we have gone up a level
7307        if (const FieldDecl *Hist = HistoryStack.pop_back_val())
7308          ValidTypes.insert(Hist->getType().getTypePtr());
7309  
7310        continue;
7311      }
7312  
7313      // Adds everything except the original parameter declaration (which is not a
7314      // field itself) to the history stack.
7315      const RecordDecl *RD;
7316      if (const FieldDecl *Field = dyn_cast<FieldDecl>(Next)) {
7317        HistoryStack.push_back(Field);
7318        RD = Field->getType()->castAs<RecordType>()->getDecl();
7319      } else {
7320        RD = cast<RecordDecl>(Next);
7321      }
7322  
7323      // Add a null marker so we know when we've gone back up a level
7324      VisitStack.push_back(nullptr);
7325  
7326      for (const auto *FD : RD->fields()) {
7327        QualType QT = FD->getType();
7328  
7329        if (ValidTypes.count(QT.getTypePtr()))
7330          continue;
7331  
7332        OpenCLParamType ParamType = getOpenCLKernelParameterType(QT);
7333        if (ParamType == ValidKernelParam)
7334          continue;
7335  
7336        if (ParamType == RecordKernelParam) {
7337          VisitStack.push_back(FD);
7338          continue;
7339        }
7340  
7341        // OpenCL v1.2 s6.9.p:
7342        // Arguments to kernel functions that are declared to be a struct or union
7343        // do not allow OpenCL objects to be passed as elements of the struct or
7344        // union.
7345        if (ParamType == PtrKernelParam || ParamType == PtrPtrKernelParam ||
7346            ParamType == PrivatePtrKernelParam) {
7347          S.Diag(Param->getLocation(),
7348                 diag::err_record_with_pointers_kernel_param)
7349            << PT->isUnionType()
7350            << PT;
7351        } else {
7352          S.Diag(Param->getLocation(), diag::err_bad_kernel_param_type) << PT;
7353        }
7354  
7355        S.Diag(PD->getLocation(), diag::note_within_field_of_type)
7356          << PD->getDeclName();
7357  
7358        // We have an error, now let's go back up through history and show where
7359        // the offending field came from
7360        for (ArrayRef<const FieldDecl *>::const_iterator
7361                 I = HistoryStack.begin() + 1,
7362                 E = HistoryStack.end();
7363             I != E; ++I) {
7364          const FieldDecl *OuterField = *I;
7365          S.Diag(OuterField->getLocation(), diag::note_within_field_of_type)
7366            << OuterField->getType();
7367        }
7368  
7369        S.Diag(FD->getLocation(), diag::note_illegal_field_declared_here)
7370          << QT->isPointerType()
7371          << QT;
7372        D.setInvalidType();
7373        return;
7374      }
7375    } while (!VisitStack.empty());
7376  }
7377  
7378  NamedDecl*
ActOnFunctionDeclarator(Scope * S,Declarator & D,DeclContext * DC,TypeSourceInfo * TInfo,LookupResult & Previous,MultiTemplateParamsArg TemplateParamLists,bool & AddToScope)7379  Sema::ActOnFunctionDeclarator(Scope *S, Declarator &D, DeclContext *DC,
7380                                TypeSourceInfo *TInfo, LookupResult &Previous,
7381                                MultiTemplateParamsArg TemplateParamLists,
7382                                bool &AddToScope) {
7383    QualType R = TInfo->getType();
7384  
7385    assert(R.getTypePtr()->isFunctionType());
7386  
7387    // TODO: consider using NameInfo for diagnostic.
7388    DeclarationNameInfo NameInfo = GetNameForDeclarator(D);
7389    DeclarationName Name = NameInfo.getName();
7390    StorageClass SC = getFunctionStorageClass(*this, D);
7391  
7392    if (DeclSpec::TSCS TSCS = D.getDeclSpec().getThreadStorageClassSpec())
7393      Diag(D.getDeclSpec().getThreadStorageClassSpecLoc(),
7394           diag::err_invalid_thread)
7395        << DeclSpec::getSpecifierName(TSCS);
7396  
7397    if (D.isFirstDeclarationOfMember())
7398      adjustMemberFunctionCC(R, D.isStaticMember(), D.isCtorOrDtor(),
7399                             D.getIdentifierLoc());
7400  
7401    bool isFriend = false;
7402    FunctionTemplateDecl *FunctionTemplate = nullptr;
7403    bool isExplicitSpecialization = false;
7404    bool isFunctionTemplateSpecialization = false;
7405  
7406    bool isDependentClassScopeExplicitSpecialization = false;
7407    bool HasExplicitTemplateArgs = false;
7408    TemplateArgumentListInfo TemplateArgs;
7409  
7410    bool isVirtualOkay = false;
7411  
7412    DeclContext *OriginalDC = DC;
7413    bool IsLocalExternDecl = adjustContextForLocalExternDecl(DC);
7414  
7415    FunctionDecl *NewFD = CreateNewFunctionDecl(*this, D, DC, R, TInfo, SC,
7416                                                isVirtualOkay);
7417    if (!NewFD) return nullptr;
7418  
7419    if (OriginalLexicalContext && OriginalLexicalContext->isObjCContainer())
7420      NewFD->setTopLevelDeclInObjCContainer();
7421  
7422    // Set the lexical context. If this is a function-scope declaration, or has a
7423    // C++ scope specifier, or is the object of a friend declaration, the lexical
7424    // context will be different from the semantic context.
7425    NewFD->setLexicalDeclContext(CurContext);
7426  
7427    if (IsLocalExternDecl)
7428      NewFD->setLocalExternDecl();
7429  
7430    if (getLangOpts().CPlusPlus) {
7431      bool isInline = D.getDeclSpec().isInlineSpecified();
7432      bool isVirtual = D.getDeclSpec().isVirtualSpecified();
7433      bool isExplicit = D.getDeclSpec().isExplicitSpecified();
7434      bool isConstexpr = D.getDeclSpec().isConstexprSpecified();
7435      bool isConcept = D.getDeclSpec().isConceptSpecified();
7436      isFriend = D.getDeclSpec().isFriendSpecified();
7437      if (isFriend && !isInline && D.isFunctionDefinition()) {
7438        // C++ [class.friend]p5
7439        //   A function can be defined in a friend declaration of a
7440        //   class . . . . Such a function is implicitly inline.
7441        NewFD->setImplicitlyInline();
7442      }
7443  
7444      // If this is a method defined in an __interface, and is not a constructor
7445      // or an overloaded operator, then set the pure flag (isVirtual will already
7446      // return true).
7447      if (const CXXRecordDecl *Parent =
7448            dyn_cast<CXXRecordDecl>(NewFD->getDeclContext())) {
7449        if (Parent->isInterface() && cast<CXXMethodDecl>(NewFD)->isUserProvided())
7450          NewFD->setPure(true);
7451  
7452        // C++ [class.union]p2
7453        //   A union can have member functions, but not virtual functions.
7454        if (isVirtual && Parent->isUnion())
7455          Diag(D.getDeclSpec().getVirtualSpecLoc(), diag::err_virtual_in_union);
7456      }
7457  
7458      SetNestedNameSpecifier(NewFD, D);
7459      isExplicitSpecialization = false;
7460      isFunctionTemplateSpecialization = false;
7461      if (D.isInvalidType())
7462        NewFD->setInvalidDecl();
7463  
7464      // Match up the template parameter lists with the scope specifier, then
7465      // determine whether we have a template or a template specialization.
7466      bool Invalid = false;
7467      if (TemplateParameterList *TemplateParams =
7468              MatchTemplateParametersToScopeSpecifier(
7469                  D.getDeclSpec().getLocStart(), D.getIdentifierLoc(),
7470                  D.getCXXScopeSpec(),
7471                  D.getName().getKind() == UnqualifiedId::IK_TemplateId
7472                      ? D.getName().TemplateId
7473                      : nullptr,
7474                  TemplateParamLists, isFriend, isExplicitSpecialization,
7475                  Invalid)) {
7476        if (TemplateParams->size() > 0) {
7477          // This is a function template
7478  
7479          // Check that we can declare a template here.
7480          if (CheckTemplateDeclScope(S, TemplateParams))
7481            NewFD->setInvalidDecl();
7482  
7483          // A destructor cannot be a template.
7484          if (Name.getNameKind() == DeclarationName::CXXDestructorName) {
7485            Diag(NewFD->getLocation(), diag::err_destructor_template);
7486            NewFD->setInvalidDecl();
7487          }
7488  
7489          // If we're adding a template to a dependent context, we may need to
7490          // rebuilding some of the types used within the template parameter list,
7491          // now that we know what the current instantiation is.
7492          if (DC->isDependentContext()) {
7493            ContextRAII SavedContext(*this, DC);
7494            if (RebuildTemplateParamsInCurrentInstantiation(TemplateParams))
7495              Invalid = true;
7496          }
7497  
7498  
7499          FunctionTemplate = FunctionTemplateDecl::Create(Context, DC,
7500                                                          NewFD->getLocation(),
7501                                                          Name, TemplateParams,
7502                                                          NewFD);
7503          FunctionTemplate->setLexicalDeclContext(CurContext);
7504          NewFD->setDescribedFunctionTemplate(FunctionTemplate);
7505  
7506          // For source fidelity, store the other template param lists.
7507          if (TemplateParamLists.size() > 1) {
7508            NewFD->setTemplateParameterListsInfo(Context,
7509                                                 TemplateParamLists.drop_back(1));
7510          }
7511        } else {
7512          // This is a function template specialization.
7513          isFunctionTemplateSpecialization = true;
7514          // For source fidelity, store all the template param lists.
7515          if (TemplateParamLists.size() > 0)
7516            NewFD->setTemplateParameterListsInfo(Context, TemplateParamLists);
7517  
7518          // C++0x [temp.expl.spec]p20 forbids "template<> friend void foo(int);".
7519          if (isFriend) {
7520            // We want to remove the "template<>", found here.
7521            SourceRange RemoveRange = TemplateParams->getSourceRange();
7522  
7523            // If we remove the template<> and the name is not a
7524            // template-id, we're actually silently creating a problem:
7525            // the friend declaration will refer to an untemplated decl,
7526            // and clearly the user wants a template specialization.  So
7527            // we need to insert '<>' after the name.
7528            SourceLocation InsertLoc;
7529            if (D.getName().getKind() != UnqualifiedId::IK_TemplateId) {
7530              InsertLoc = D.getName().getSourceRange().getEnd();
7531              InsertLoc = getLocForEndOfToken(InsertLoc);
7532            }
7533  
7534            Diag(D.getIdentifierLoc(), diag::err_template_spec_decl_friend)
7535              << Name << RemoveRange
7536              << FixItHint::CreateRemoval(RemoveRange)
7537              << FixItHint::CreateInsertion(InsertLoc, "<>");
7538          }
7539        }
7540      }
7541      else {
7542        // All template param lists were matched against the scope specifier:
7543        // this is NOT (an explicit specialization of) a template.
7544        if (TemplateParamLists.size() > 0)
7545          // For source fidelity, store all the template param lists.
7546          NewFD->setTemplateParameterListsInfo(Context, TemplateParamLists);
7547      }
7548  
7549      if (Invalid) {
7550        NewFD->setInvalidDecl();
7551        if (FunctionTemplate)
7552          FunctionTemplate->setInvalidDecl();
7553      }
7554  
7555      // C++ [dcl.fct.spec]p5:
7556      //   The virtual specifier shall only be used in declarations of
7557      //   nonstatic class member functions that appear within a
7558      //   member-specification of a class declaration; see 10.3.
7559      //
7560      if (isVirtual && !NewFD->isInvalidDecl()) {
7561        if (!isVirtualOkay) {
7562          Diag(D.getDeclSpec().getVirtualSpecLoc(),
7563               diag::err_virtual_non_function);
7564        } else if (!CurContext->isRecord()) {
7565          // 'virtual' was specified outside of the class.
7566          Diag(D.getDeclSpec().getVirtualSpecLoc(),
7567               diag::err_virtual_out_of_class)
7568            << FixItHint::CreateRemoval(D.getDeclSpec().getVirtualSpecLoc());
7569        } else if (NewFD->getDescribedFunctionTemplate()) {
7570          // C++ [temp.mem]p3:
7571          //  A member function template shall not be virtual.
7572          Diag(D.getDeclSpec().getVirtualSpecLoc(),
7573               diag::err_virtual_member_function_template)
7574            << FixItHint::CreateRemoval(D.getDeclSpec().getVirtualSpecLoc());
7575        } else {
7576          // Okay: Add virtual to the method.
7577          NewFD->setVirtualAsWritten(true);
7578        }
7579  
7580        if (getLangOpts().CPlusPlus14 &&
7581            NewFD->getReturnType()->isUndeducedType())
7582          Diag(D.getDeclSpec().getVirtualSpecLoc(), diag::err_auto_fn_virtual);
7583      }
7584  
7585      if (getLangOpts().CPlusPlus14 &&
7586          (NewFD->isDependentContext() ||
7587           (isFriend && CurContext->isDependentContext())) &&
7588          NewFD->getReturnType()->isUndeducedType()) {
7589        // If the function template is referenced directly (for instance, as a
7590        // member of the current instantiation), pretend it has a dependent type.
7591        // This is not really justified by the standard, but is the only sane
7592        // thing to do.
7593        // FIXME: For a friend function, we have not marked the function as being
7594        // a friend yet, so 'isDependentContext' on the FD doesn't work.
7595        const FunctionProtoType *FPT =
7596            NewFD->getType()->castAs<FunctionProtoType>();
7597        QualType Result =
7598            SubstAutoType(FPT->getReturnType(), Context.DependentTy);
7599        NewFD->setType(Context.getFunctionType(Result, FPT->getParamTypes(),
7600                                               FPT->getExtProtoInfo()));
7601      }
7602  
7603      // C++ [dcl.fct.spec]p3:
7604      //  The inline specifier shall not appear on a block scope function
7605      //  declaration.
7606      if (isInline && !NewFD->isInvalidDecl()) {
7607        if (CurContext->isFunctionOrMethod()) {
7608          // 'inline' is not allowed on block scope function declaration.
7609          Diag(D.getDeclSpec().getInlineSpecLoc(),
7610               diag::err_inline_declaration_block_scope) << Name
7611            << FixItHint::CreateRemoval(D.getDeclSpec().getInlineSpecLoc());
7612        }
7613      }
7614  
7615      // C++ [dcl.fct.spec]p6:
7616      //  The explicit specifier shall be used only in the declaration of a
7617      //  constructor or conversion function within its class definition;
7618      //  see 12.3.1 and 12.3.2.
7619      if (isExplicit && !NewFD->isInvalidDecl()) {
7620        if (!CurContext->isRecord()) {
7621          // 'explicit' was specified outside of the class.
7622          Diag(D.getDeclSpec().getExplicitSpecLoc(),
7623               diag::err_explicit_out_of_class)
7624            << FixItHint::CreateRemoval(D.getDeclSpec().getExplicitSpecLoc());
7625        } else if (!isa<CXXConstructorDecl>(NewFD) &&
7626                   !isa<CXXConversionDecl>(NewFD)) {
7627          // 'explicit' was specified on a function that wasn't a constructor
7628          // or conversion function.
7629          Diag(D.getDeclSpec().getExplicitSpecLoc(),
7630               diag::err_explicit_non_ctor_or_conv_function)
7631            << FixItHint::CreateRemoval(D.getDeclSpec().getExplicitSpecLoc());
7632        }
7633      }
7634  
7635      if (isConstexpr) {
7636        // C++11 [dcl.constexpr]p2: constexpr functions and constexpr constructors
7637        // are implicitly inline.
7638        NewFD->setImplicitlyInline();
7639  
7640        // C++11 [dcl.constexpr]p3: functions declared constexpr are required to
7641        // be either constructors or to return a literal type. Therefore,
7642        // destructors cannot be declared constexpr.
7643        if (isa<CXXDestructorDecl>(NewFD))
7644          Diag(D.getDeclSpec().getConstexprSpecLoc(), diag::err_constexpr_dtor);
7645      }
7646  
7647      if (isConcept) {
7648        // C++ Concepts TS [dcl.spec.concept]p1: The concept specifier shall be
7649        // applied only to the definition of a function template [...]
7650        if (!D.isFunctionDefinition()) {
7651          Diag(D.getDeclSpec().getConceptSpecLoc(),
7652               diag::err_function_concept_not_defined);
7653          NewFD->setInvalidDecl();
7654        }
7655  
7656        // C++ Concepts TS [dcl.spec.concept]p1: [...] A function concept shall
7657        // have no exception-specification and is treated as if it were specified
7658        // with noexcept(true) (15.4). [...]
7659        if (const FunctionProtoType *FPT = R->getAs<FunctionProtoType>()) {
7660          if (FPT->hasExceptionSpec()) {
7661            SourceRange Range;
7662            if (D.isFunctionDeclarator())
7663              Range = D.getFunctionTypeInfo().getExceptionSpecRange();
7664            Diag(NewFD->getLocation(), diag::err_function_concept_exception_spec)
7665                << FixItHint::CreateRemoval(Range);
7666            NewFD->setInvalidDecl();
7667          } else {
7668            Context.adjustExceptionSpec(NewFD, EST_BasicNoexcept);
7669          }
7670  
7671          // C++ Concepts TS [dcl.spec.concept]p5: A function concept has the
7672          // following restrictions:
7673          // - The declaration's parameter list shall be equivalent to an empty
7674          //   parameter list.
7675          if (FPT->getNumParams() > 0 || FPT->isVariadic())
7676            Diag(NewFD->getLocation(), diag::err_function_concept_with_params);
7677        }
7678  
7679        // C++ Concepts TS [dcl.spec.concept]p2: Every concept definition is
7680        // implicity defined to be a constexpr declaration (implicitly inline)
7681        NewFD->setImplicitlyInline();
7682  
7683        // C++ Concepts TS [dcl.spec.concept]p2: A concept definition shall not
7684        // be declared with the thread_local, inline, friend, or constexpr
7685        // specifiers, [...]
7686        if (isInline) {
7687          Diag(D.getDeclSpec().getInlineSpecLoc(),
7688               diag::err_concept_decl_invalid_specifiers)
7689              << 1 << 1;
7690          NewFD->setInvalidDecl(true);
7691        }
7692  
7693        if (isFriend) {
7694          Diag(D.getDeclSpec().getFriendSpecLoc(),
7695               diag::err_concept_decl_invalid_specifiers)
7696              << 1 << 2;
7697          NewFD->setInvalidDecl(true);
7698        }
7699  
7700        if (isConstexpr) {
7701          Diag(D.getDeclSpec().getConstexprSpecLoc(),
7702               diag::err_concept_decl_invalid_specifiers)
7703              << 1 << 3;
7704          NewFD->setInvalidDecl(true);
7705        }
7706      }
7707  
7708      // If __module_private__ was specified, mark the function accordingly.
7709      if (D.getDeclSpec().isModulePrivateSpecified()) {
7710        if (isFunctionTemplateSpecialization) {
7711          SourceLocation ModulePrivateLoc
7712            = D.getDeclSpec().getModulePrivateSpecLoc();
7713          Diag(ModulePrivateLoc, diag::err_module_private_specialization)
7714            << 0
7715            << FixItHint::CreateRemoval(ModulePrivateLoc);
7716        } else {
7717          NewFD->setModulePrivate();
7718          if (FunctionTemplate)
7719            FunctionTemplate->setModulePrivate();
7720        }
7721      }
7722  
7723      if (isFriend) {
7724        if (FunctionTemplate) {
7725          FunctionTemplate->setObjectOfFriendDecl();
7726          FunctionTemplate->setAccess(AS_public);
7727        }
7728        NewFD->setObjectOfFriendDecl();
7729        NewFD->setAccess(AS_public);
7730      }
7731  
7732      // If a function is defined as defaulted or deleted, mark it as such now.
7733      // FIXME: Does this ever happen? ActOnStartOfFunctionDef forces the function
7734      // definition kind to FDK_Definition.
7735      switch (D.getFunctionDefinitionKind()) {
7736        case FDK_Declaration:
7737        case FDK_Definition:
7738          break;
7739  
7740        case FDK_Defaulted:
7741          NewFD->setDefaulted();
7742          break;
7743  
7744        case FDK_Deleted:
7745          NewFD->setDeletedAsWritten();
7746          break;
7747      }
7748  
7749      if (isa<CXXMethodDecl>(NewFD) && DC == CurContext &&
7750          D.isFunctionDefinition()) {
7751        // C++ [class.mfct]p2:
7752        //   A member function may be defined (8.4) in its class definition, in
7753        //   which case it is an inline member function (7.1.2)
7754        NewFD->setImplicitlyInline();
7755      }
7756  
7757      if (SC == SC_Static && isa<CXXMethodDecl>(NewFD) &&
7758          !CurContext->isRecord()) {
7759        // C++ [class.static]p1:
7760        //   A data or function member of a class may be declared static
7761        //   in a class definition, in which case it is a static member of
7762        //   the class.
7763  
7764        // Complain about the 'static' specifier if it's on an out-of-line
7765        // member function definition.
7766        Diag(D.getDeclSpec().getStorageClassSpecLoc(),
7767             diag::err_static_out_of_line)
7768          << FixItHint::CreateRemoval(D.getDeclSpec().getStorageClassSpecLoc());
7769      }
7770  
7771      // C++11 [except.spec]p15:
7772      //   A deallocation function with no exception-specification is treated
7773      //   as if it were specified with noexcept(true).
7774      const FunctionProtoType *FPT = R->getAs<FunctionProtoType>();
7775      if ((Name.getCXXOverloadedOperator() == OO_Delete ||
7776           Name.getCXXOverloadedOperator() == OO_Array_Delete) &&
7777          getLangOpts().CPlusPlus11 && FPT && !FPT->hasExceptionSpec())
7778        NewFD->setType(Context.getFunctionType(
7779            FPT->getReturnType(), FPT->getParamTypes(),
7780            FPT->getExtProtoInfo().withExceptionSpec(EST_BasicNoexcept)));
7781    }
7782  
7783    // Filter out previous declarations that don't match the scope.
7784    FilterLookupForScope(Previous, OriginalDC, S, shouldConsiderLinkage(NewFD),
7785                         D.getCXXScopeSpec().isNotEmpty() ||
7786                         isExplicitSpecialization ||
7787                         isFunctionTemplateSpecialization);
7788  
7789    // Handle GNU asm-label extension (encoded as an attribute).
7790    if (Expr *E = (Expr*) D.getAsmLabel()) {
7791      // The parser guarantees this is a string.
7792      StringLiteral *SE = cast<StringLiteral>(E);
7793      NewFD->addAttr(::new (Context) AsmLabelAttr(SE->getStrTokenLoc(0), Context,
7794                                                  SE->getString(), 0));
7795    } else if (!ExtnameUndeclaredIdentifiers.empty()) {
7796      llvm::DenseMap<IdentifierInfo*,AsmLabelAttr*>::iterator I =
7797        ExtnameUndeclaredIdentifiers.find(NewFD->getIdentifier());
7798      if (I != ExtnameUndeclaredIdentifiers.end()) {
7799        if (isDeclExternC(NewFD)) {
7800          NewFD->addAttr(I->second);
7801          ExtnameUndeclaredIdentifiers.erase(I);
7802        } else
7803          Diag(NewFD->getLocation(), diag::warn_redefine_extname_not_applied)
7804              << /*Variable*/0 << NewFD;
7805      }
7806    }
7807  
7808    // Copy the parameter declarations from the declarator D to the function
7809    // declaration NewFD, if they are available.  First scavenge them into Params.
7810    SmallVector<ParmVarDecl*, 16> Params;
7811    if (D.isFunctionDeclarator()) {
7812      DeclaratorChunk::FunctionTypeInfo &FTI = D.getFunctionTypeInfo();
7813  
7814      // Check for C99 6.7.5.3p10 - foo(void) is a non-varargs
7815      // function that takes no arguments, not a function that takes a
7816      // single void argument.
7817      // We let through "const void" here because Sema::GetTypeForDeclarator
7818      // already checks for that case.
7819      if (FTIHasNonVoidParameters(FTI) && FTI.Params[0].Param) {
7820        for (unsigned i = 0, e = FTI.NumParams; i != e; ++i) {
7821          ParmVarDecl *Param = cast<ParmVarDecl>(FTI.Params[i].Param);
7822          assert(Param->getDeclContext() != NewFD && "Was set before ?");
7823          Param->setDeclContext(NewFD);
7824          Params.push_back(Param);
7825  
7826          if (Param->isInvalidDecl())
7827            NewFD->setInvalidDecl();
7828        }
7829      }
7830  
7831    } else if (const FunctionProtoType *FT = R->getAs<FunctionProtoType>()) {
7832      // When we're declaring a function with a typedef, typeof, etc as in the
7833      // following example, we'll need to synthesize (unnamed)
7834      // parameters for use in the declaration.
7835      //
7836      // @code
7837      // typedef void fn(int);
7838      // fn f;
7839      // @endcode
7840  
7841      // Synthesize a parameter for each argument type.
7842      for (const auto &AI : FT->param_types()) {
7843        ParmVarDecl *Param =
7844            BuildParmVarDeclForTypedef(NewFD, D.getIdentifierLoc(), AI);
7845        Param->setScopeInfo(0, Params.size());
7846        Params.push_back(Param);
7847      }
7848    } else {
7849      assert(R->isFunctionNoProtoType() && NewFD->getNumParams() == 0 &&
7850             "Should not need args for typedef of non-prototype fn");
7851    }
7852  
7853    // Finally, we know we have the right number of parameters, install them.
7854    NewFD->setParams(Params);
7855  
7856    // Find all anonymous symbols defined during the declaration of this function
7857    // and add to NewFD. This lets us track decls such 'enum Y' in:
7858    //
7859    //   void f(enum Y {AA} x) {}
7860    //
7861    // which would otherwise incorrectly end up in the translation unit scope.
7862    NewFD->setDeclsInPrototypeScope(DeclsInPrototypeScope);
7863    DeclsInPrototypeScope.clear();
7864  
7865    if (D.getDeclSpec().isNoreturnSpecified())
7866      NewFD->addAttr(
7867          ::new(Context) C11NoReturnAttr(D.getDeclSpec().getNoreturnSpecLoc(),
7868                                         Context, 0));
7869  
7870    // Functions returning a variably modified type violate C99 6.7.5.2p2
7871    // because all functions have linkage.
7872    if (!NewFD->isInvalidDecl() &&
7873        NewFD->getReturnType()->isVariablyModifiedType()) {
7874      Diag(NewFD->getLocation(), diag::err_vm_func_decl);
7875      NewFD->setInvalidDecl();
7876    }
7877  
7878    // Apply an implicit SectionAttr if #pragma code_seg is active.
7879    if (CodeSegStack.CurrentValue && D.isFunctionDefinition() &&
7880        !NewFD->hasAttr<SectionAttr>()) {
7881      NewFD->addAttr(
7882          SectionAttr::CreateImplicit(Context, SectionAttr::Declspec_allocate,
7883                                      CodeSegStack.CurrentValue->getString(),
7884                                      CodeSegStack.CurrentPragmaLocation));
7885      if (UnifySection(CodeSegStack.CurrentValue->getString(),
7886                       ASTContext::PSF_Implicit | ASTContext::PSF_Execute |
7887                           ASTContext::PSF_Read,
7888                       NewFD))
7889        NewFD->dropAttr<SectionAttr>();
7890    }
7891  
7892    // Handle attributes.
7893    ProcessDeclAttributes(S, NewFD, D);
7894  
7895    if (getLangOpts().OpenCL) {
7896      // OpenCL v1.1 s6.5: Using an address space qualifier in a function return
7897      // type declaration will generate a compilation error.
7898      unsigned AddressSpace = NewFD->getReturnType().getAddressSpace();
7899      if (AddressSpace == LangAS::opencl_local ||
7900          AddressSpace == LangAS::opencl_global ||
7901          AddressSpace == LangAS::opencl_constant) {
7902        Diag(NewFD->getLocation(),
7903             diag::err_opencl_return_value_with_address_space);
7904        NewFD->setInvalidDecl();
7905      }
7906    }
7907  
7908    if (!getLangOpts().CPlusPlus) {
7909      // Perform semantic checking on the function declaration.
7910      bool isExplicitSpecialization=false;
7911      if (!NewFD->isInvalidDecl() && NewFD->isMain())
7912        CheckMain(NewFD, D.getDeclSpec());
7913  
7914      if (!NewFD->isInvalidDecl() && NewFD->isMSVCRTEntryPoint())
7915        CheckMSVCRTEntryPoint(NewFD);
7916  
7917      if (!NewFD->isInvalidDecl())
7918        D.setRedeclaration(CheckFunctionDeclaration(S, NewFD, Previous,
7919                                                    isExplicitSpecialization));
7920      else if (!Previous.empty())
7921        // Recover gracefully from an invalid redeclaration.
7922        D.setRedeclaration(true);
7923      assert((NewFD->isInvalidDecl() || !D.isRedeclaration() ||
7924              Previous.getResultKind() != LookupResult::FoundOverloaded) &&
7925             "previous declaration set still overloaded");
7926  
7927      // Diagnose no-prototype function declarations with calling conventions that
7928      // don't support variadic calls. Only do this in C and do it after merging
7929      // possibly prototyped redeclarations.
7930      const FunctionType *FT = NewFD->getType()->castAs<FunctionType>();
7931      if (isa<FunctionNoProtoType>(FT) && !D.isFunctionDefinition()) {
7932        CallingConv CC = FT->getExtInfo().getCC();
7933        if (!supportsVariadicCall(CC)) {
7934          // Windows system headers sometimes accidentally use stdcall without
7935          // (void) parameters, so we relax this to a warning.
7936          int DiagID =
7937              CC == CC_X86StdCall ? diag::warn_cconv_knr : diag::err_cconv_knr;
7938          Diag(NewFD->getLocation(), DiagID)
7939              << FunctionType::getNameForCallConv(CC);
7940        }
7941      }
7942    } else {
7943      // C++11 [replacement.functions]p3:
7944      //  The program's definitions shall not be specified as inline.
7945      //
7946      // N.B. We diagnose declarations instead of definitions per LWG issue 2340.
7947      //
7948      // Suppress the diagnostic if the function is __attribute__((used)), since
7949      // that forces an external definition to be emitted.
7950      if (D.getDeclSpec().isInlineSpecified() &&
7951          NewFD->isReplaceableGlobalAllocationFunction() &&
7952          !NewFD->hasAttr<UsedAttr>())
7953        Diag(D.getDeclSpec().getInlineSpecLoc(),
7954             diag::ext_operator_new_delete_declared_inline)
7955          << NewFD->getDeclName();
7956  
7957      // If the declarator is a template-id, translate the parser's template
7958      // argument list into our AST format.
7959      if (D.getName().getKind() == UnqualifiedId::IK_TemplateId) {
7960        TemplateIdAnnotation *TemplateId = D.getName().TemplateId;
7961        TemplateArgs.setLAngleLoc(TemplateId->LAngleLoc);
7962        TemplateArgs.setRAngleLoc(TemplateId->RAngleLoc);
7963        ASTTemplateArgsPtr TemplateArgsPtr(TemplateId->getTemplateArgs(),
7964                                           TemplateId->NumArgs);
7965        translateTemplateArguments(TemplateArgsPtr,
7966                                   TemplateArgs);
7967  
7968        HasExplicitTemplateArgs = true;
7969  
7970        if (NewFD->isInvalidDecl()) {
7971          HasExplicitTemplateArgs = false;
7972        } else if (FunctionTemplate) {
7973          // Function template with explicit template arguments.
7974          Diag(D.getIdentifierLoc(), diag::err_function_template_partial_spec)
7975            << SourceRange(TemplateId->LAngleLoc, TemplateId->RAngleLoc);
7976  
7977          HasExplicitTemplateArgs = false;
7978        } else {
7979          assert((isFunctionTemplateSpecialization ||
7980                  D.getDeclSpec().isFriendSpecified()) &&
7981                 "should have a 'template<>' for this decl");
7982          // "friend void foo<>(int);" is an implicit specialization decl.
7983          isFunctionTemplateSpecialization = true;
7984        }
7985      } else if (isFriend && isFunctionTemplateSpecialization) {
7986        // This combination is only possible in a recovery case;  the user
7987        // wrote something like:
7988        //   template <> friend void foo(int);
7989        // which we're recovering from as if the user had written:
7990        //   friend void foo<>(int);
7991        // Go ahead and fake up a template id.
7992        HasExplicitTemplateArgs = true;
7993        TemplateArgs.setLAngleLoc(D.getIdentifierLoc());
7994        TemplateArgs.setRAngleLoc(D.getIdentifierLoc());
7995      }
7996  
7997      // If it's a friend (and only if it's a friend), it's possible
7998      // that either the specialized function type or the specialized
7999      // template is dependent, and therefore matching will fail.  In
8000      // this case, don't check the specialization yet.
8001      bool InstantiationDependent = false;
8002      if (isFunctionTemplateSpecialization && isFriend &&
8003          (NewFD->getType()->isDependentType() || DC->isDependentContext() ||
8004           TemplateSpecializationType::anyDependentTemplateArguments(
8005              TemplateArgs.getArgumentArray(), TemplateArgs.size(),
8006              InstantiationDependent))) {
8007        assert(HasExplicitTemplateArgs &&
8008               "friend function specialization without template args");
8009        if (CheckDependentFunctionTemplateSpecialization(NewFD, TemplateArgs,
8010                                                         Previous))
8011          NewFD->setInvalidDecl();
8012      } else if (isFunctionTemplateSpecialization) {
8013        if (CurContext->isDependentContext() && CurContext->isRecord()
8014            && !isFriend) {
8015          isDependentClassScopeExplicitSpecialization = true;
8016          Diag(NewFD->getLocation(), getLangOpts().MicrosoftExt ?
8017            diag::ext_function_specialization_in_class :
8018            diag::err_function_specialization_in_class)
8019            << NewFD->getDeclName();
8020        } else if (CheckFunctionTemplateSpecialization(NewFD,
8021                                    (HasExplicitTemplateArgs ? &TemplateArgs
8022                                                             : nullptr),
8023                                                       Previous))
8024          NewFD->setInvalidDecl();
8025  
8026        // C++ [dcl.stc]p1:
8027        //   A storage-class-specifier shall not be specified in an explicit
8028        //   specialization (14.7.3)
8029        FunctionTemplateSpecializationInfo *Info =
8030            NewFD->getTemplateSpecializationInfo();
8031        if (Info && SC != SC_None) {
8032          if (SC != Info->getTemplate()->getTemplatedDecl()->getStorageClass())
8033            Diag(NewFD->getLocation(),
8034                 diag::err_explicit_specialization_inconsistent_storage_class)
8035              << SC
8036              << FixItHint::CreateRemoval(
8037                                        D.getDeclSpec().getStorageClassSpecLoc());
8038  
8039          else
8040            Diag(NewFD->getLocation(),
8041                 diag::ext_explicit_specialization_storage_class)
8042              << FixItHint::CreateRemoval(
8043                                        D.getDeclSpec().getStorageClassSpecLoc());
8044        }
8045  
8046      } else if (isExplicitSpecialization && isa<CXXMethodDecl>(NewFD)) {
8047        if (CheckMemberSpecialization(NewFD, Previous))
8048            NewFD->setInvalidDecl();
8049      }
8050  
8051      // Perform semantic checking on the function declaration.
8052      if (!isDependentClassScopeExplicitSpecialization) {
8053        if (!NewFD->isInvalidDecl() && NewFD->isMain())
8054          CheckMain(NewFD, D.getDeclSpec());
8055  
8056        if (!NewFD->isInvalidDecl() && NewFD->isMSVCRTEntryPoint())
8057          CheckMSVCRTEntryPoint(NewFD);
8058  
8059        if (!NewFD->isInvalidDecl())
8060          D.setRedeclaration(CheckFunctionDeclaration(S, NewFD, Previous,
8061                                                      isExplicitSpecialization));
8062        else if (!Previous.empty())
8063          // Recover gracefully from an invalid redeclaration.
8064          D.setRedeclaration(true);
8065      }
8066  
8067      assert((NewFD->isInvalidDecl() || !D.isRedeclaration() ||
8068              Previous.getResultKind() != LookupResult::FoundOverloaded) &&
8069             "previous declaration set still overloaded");
8070  
8071      NamedDecl *PrincipalDecl = (FunctionTemplate
8072                                  ? cast<NamedDecl>(FunctionTemplate)
8073                                  : NewFD);
8074  
8075      if (isFriend && D.isRedeclaration()) {
8076        AccessSpecifier Access = AS_public;
8077        if (!NewFD->isInvalidDecl())
8078          Access = NewFD->getPreviousDecl()->getAccess();
8079  
8080        NewFD->setAccess(Access);
8081        if (FunctionTemplate) FunctionTemplate->setAccess(Access);
8082      }
8083  
8084      if (NewFD->isOverloadedOperator() && !DC->isRecord() &&
8085          PrincipalDecl->isInIdentifierNamespace(Decl::IDNS_Ordinary))
8086        PrincipalDecl->setNonMemberOperator();
8087  
8088      // If we have a function template, check the template parameter
8089      // list. This will check and merge default template arguments.
8090      if (FunctionTemplate) {
8091        FunctionTemplateDecl *PrevTemplate =
8092                                       FunctionTemplate->getPreviousDecl();
8093        CheckTemplateParameterList(FunctionTemplate->getTemplateParameters(),
8094                         PrevTemplate ? PrevTemplate->getTemplateParameters()
8095                                      : nullptr,
8096                              D.getDeclSpec().isFriendSpecified()
8097                                ? (D.isFunctionDefinition()
8098                                     ? TPC_FriendFunctionTemplateDefinition
8099                                     : TPC_FriendFunctionTemplate)
8100                                : (D.getCXXScopeSpec().isSet() &&
8101                                   DC && DC->isRecord() &&
8102                                   DC->isDependentContext())
8103                                    ? TPC_ClassTemplateMember
8104                                    : TPC_FunctionTemplate);
8105      }
8106  
8107      if (NewFD->isInvalidDecl()) {
8108        // Ignore all the rest of this.
8109      } else if (!D.isRedeclaration()) {
8110        struct ActOnFDArgs ExtraArgs = { S, D, TemplateParamLists,
8111                                         AddToScope };
8112        // Fake up an access specifier if it's supposed to be a class member.
8113        if (isa<CXXRecordDecl>(NewFD->getDeclContext()))
8114          NewFD->setAccess(AS_public);
8115  
8116        // Qualified decls generally require a previous declaration.
8117        if (D.getCXXScopeSpec().isSet()) {
8118          // ...with the major exception of templated-scope or
8119          // dependent-scope friend declarations.
8120  
8121          // TODO: we currently also suppress this check in dependent
8122          // contexts because (1) the parameter depth will be off when
8123          // matching friend templates and (2) we might actually be
8124          // selecting a friend based on a dependent factor.  But there
8125          // are situations where these conditions don't apply and we
8126          // can actually do this check immediately.
8127          if (isFriend &&
8128              (TemplateParamLists.size() ||
8129               D.getCXXScopeSpec().getScopeRep()->isDependent() ||
8130               CurContext->isDependentContext())) {
8131            // ignore these
8132          } else {
8133            // The user tried to provide an out-of-line definition for a
8134            // function that is a member of a class or namespace, but there
8135            // was no such member function declared (C++ [class.mfct]p2,
8136            // C++ [namespace.memdef]p2). For example:
8137            //
8138            // class X {
8139            //   void f() const;
8140            // };
8141            //
8142            // void X::f() { } // ill-formed
8143            //
8144            // Complain about this problem, and attempt to suggest close
8145            // matches (e.g., those that differ only in cv-qualifiers and
8146            // whether the parameter types are references).
8147  
8148            if (NamedDecl *Result = DiagnoseInvalidRedeclaration(
8149                    *this, Previous, NewFD, ExtraArgs, false, nullptr)) {
8150              AddToScope = ExtraArgs.AddToScope;
8151              return Result;
8152            }
8153          }
8154  
8155          // Unqualified local friend declarations are required to resolve
8156          // to something.
8157        } else if (isFriend && cast<CXXRecordDecl>(CurContext)->isLocalClass()) {
8158          if (NamedDecl *Result = DiagnoseInvalidRedeclaration(
8159                  *this, Previous, NewFD, ExtraArgs, true, S)) {
8160            AddToScope = ExtraArgs.AddToScope;
8161            return Result;
8162          }
8163        }
8164  
8165      } else if (!D.isFunctionDefinition() &&
8166                 isa<CXXMethodDecl>(NewFD) && NewFD->isOutOfLine() &&
8167                 !isFriend && !isFunctionTemplateSpecialization &&
8168                 !isExplicitSpecialization) {
8169        // An out-of-line member function declaration must also be a
8170        // definition (C++ [class.mfct]p2).
8171        // Note that this is not the case for explicit specializations of
8172        // function templates or member functions of class templates, per
8173        // C++ [temp.expl.spec]p2. We also allow these declarations as an
8174        // extension for compatibility with old SWIG code which likes to
8175        // generate them.
8176        Diag(NewFD->getLocation(), diag::ext_out_of_line_declaration)
8177          << D.getCXXScopeSpec().getRange();
8178      }
8179    }
8180  
8181    ProcessPragmaWeak(S, NewFD);
8182    checkAttributesAfterMerging(*this, *NewFD);
8183  
8184    AddKnownFunctionAttributes(NewFD);
8185  
8186    if (NewFD->hasAttr<OverloadableAttr>() &&
8187        !NewFD->getType()->getAs<FunctionProtoType>()) {
8188      Diag(NewFD->getLocation(),
8189           diag::err_attribute_overloadable_no_prototype)
8190        << NewFD;
8191  
8192      // Turn this into a variadic function with no parameters.
8193      const FunctionType *FT = NewFD->getType()->getAs<FunctionType>();
8194      FunctionProtoType::ExtProtoInfo EPI(
8195          Context.getDefaultCallingConvention(true, false));
8196      EPI.Variadic = true;
8197      EPI.ExtInfo = FT->getExtInfo();
8198  
8199      QualType R = Context.getFunctionType(FT->getReturnType(), None, EPI);
8200      NewFD->setType(R);
8201    }
8202  
8203    // If there's a #pragma GCC visibility in scope, and this isn't a class
8204    // member, set the visibility of this function.
8205    if (!DC->isRecord() && NewFD->isExternallyVisible())
8206      AddPushedVisibilityAttribute(NewFD);
8207  
8208    // If there's a #pragma clang arc_cf_code_audited in scope, consider
8209    // marking the function.
8210    AddCFAuditedAttribute(NewFD);
8211  
8212    // If this is a function definition, check if we have to apply optnone due to
8213    // a pragma.
8214    if(D.isFunctionDefinition())
8215      AddRangeBasedOptnone(NewFD);
8216  
8217    // If this is the first declaration of an extern C variable, update
8218    // the map of such variables.
8219    if (NewFD->isFirstDecl() && !NewFD->isInvalidDecl() &&
8220        isIncompleteDeclExternC(*this, NewFD))
8221      RegisterLocallyScopedExternCDecl(NewFD, S);
8222  
8223    // Set this FunctionDecl's range up to the right paren.
8224    NewFD->setRangeEnd(D.getSourceRange().getEnd());
8225  
8226    if (D.isRedeclaration() && !Previous.empty()) {
8227      checkDLLAttributeRedeclaration(
8228          *this, dyn_cast<NamedDecl>(Previous.getRepresentativeDecl()), NewFD,
8229          isExplicitSpecialization || isFunctionTemplateSpecialization);
8230    }
8231  
8232    if (getLangOpts().CPlusPlus) {
8233      if (FunctionTemplate) {
8234        if (NewFD->isInvalidDecl())
8235          FunctionTemplate->setInvalidDecl();
8236        return FunctionTemplate;
8237      }
8238    }
8239  
8240    if (NewFD->hasAttr<OpenCLKernelAttr>()) {
8241      // OpenCL v1.2 s6.8 static is invalid for kernel functions.
8242      if ((getLangOpts().OpenCLVersion >= 120)
8243          && (SC == SC_Static)) {
8244        Diag(D.getIdentifierLoc(), diag::err_static_kernel);
8245        D.setInvalidType();
8246      }
8247  
8248      // OpenCL v1.2, s6.9 -- Kernels can only have return type void.
8249      if (!NewFD->getReturnType()->isVoidType()) {
8250        SourceRange RTRange = NewFD->getReturnTypeSourceRange();
8251        Diag(D.getIdentifierLoc(), diag::err_expected_kernel_void_return_type)
8252            << (RTRange.isValid() ? FixItHint::CreateReplacement(RTRange, "void")
8253                                  : FixItHint());
8254        D.setInvalidType();
8255      }
8256  
8257      llvm::SmallPtrSet<const Type *, 16> ValidTypes;
8258      for (auto Param : NewFD->params())
8259        checkIsValidOpenCLKernelParameter(*this, D, Param, ValidTypes);
8260    }
8261  
8262    MarkUnusedFileScopedDecl(NewFD);
8263  
8264    if (getLangOpts().CUDA)
8265      if (IdentifierInfo *II = NewFD->getIdentifier())
8266        if (!NewFD->isInvalidDecl() &&
8267            NewFD->getDeclContext()->getRedeclContext()->isTranslationUnit()) {
8268          if (II->isStr("cudaConfigureCall")) {
8269            if (!R->getAs<FunctionType>()->getReturnType()->isScalarType())
8270              Diag(NewFD->getLocation(), diag::err_config_scalar_return);
8271  
8272            Context.setcudaConfigureCallDecl(NewFD);
8273          }
8274        }
8275  
8276    // Here we have an function template explicit specialization at class scope.
8277    // The actually specialization will be postponed to template instatiation
8278    // time via the ClassScopeFunctionSpecializationDecl node.
8279    if (isDependentClassScopeExplicitSpecialization) {
8280      ClassScopeFunctionSpecializationDecl *NewSpec =
8281                           ClassScopeFunctionSpecializationDecl::Create(
8282                                  Context, CurContext, SourceLocation(),
8283                                  cast<CXXMethodDecl>(NewFD),
8284                                  HasExplicitTemplateArgs, TemplateArgs);
8285      CurContext->addDecl(NewSpec);
8286      AddToScope = false;
8287    }
8288  
8289    return NewFD;
8290  }
8291  
8292  /// \brief Perform semantic checking of a new function declaration.
8293  ///
8294  /// Performs semantic analysis of the new function declaration
8295  /// NewFD. This routine performs all semantic checking that does not
8296  /// require the actual declarator involved in the declaration, and is
8297  /// used both for the declaration of functions as they are parsed
8298  /// (called via ActOnDeclarator) and for the declaration of functions
8299  /// that have been instantiated via C++ template instantiation (called
8300  /// via InstantiateDecl).
8301  ///
8302  /// \param IsExplicitSpecialization whether this new function declaration is
8303  /// an explicit specialization of the previous declaration.
8304  ///
8305  /// This sets NewFD->isInvalidDecl() to true if there was an error.
8306  ///
8307  /// \returns true if the function declaration is a redeclaration.
CheckFunctionDeclaration(Scope * S,FunctionDecl * NewFD,LookupResult & Previous,bool IsExplicitSpecialization)8308  bool Sema::CheckFunctionDeclaration(Scope *S, FunctionDecl *NewFD,
8309                                      LookupResult &Previous,
8310                                      bool IsExplicitSpecialization) {
8311    assert(!NewFD->getReturnType()->isVariablyModifiedType() &&
8312           "Variably modified return types are not handled here");
8313  
8314    // Determine whether the type of this function should be merged with
8315    // a previous visible declaration. This never happens for functions in C++,
8316    // and always happens in C if the previous declaration was visible.
8317    bool MergeTypeWithPrevious = !getLangOpts().CPlusPlus &&
8318                                 !Previous.isShadowed();
8319  
8320    bool Redeclaration = false;
8321    NamedDecl *OldDecl = nullptr;
8322  
8323    // Merge or overload the declaration with an existing declaration of
8324    // the same name, if appropriate.
8325    if (!Previous.empty()) {
8326      // Determine whether NewFD is an overload of PrevDecl or
8327      // a declaration that requires merging. If it's an overload,
8328      // there's no more work to do here; we'll just add the new
8329      // function to the scope.
8330      if (!AllowOverloadingOfFunction(Previous, Context)) {
8331        NamedDecl *Candidate = Previous.getRepresentativeDecl();
8332        if (shouldLinkPossiblyHiddenDecl(Candidate, NewFD)) {
8333          Redeclaration = true;
8334          OldDecl = Candidate;
8335        }
8336      } else {
8337        switch (CheckOverload(S, NewFD, Previous, OldDecl,
8338                              /*NewIsUsingDecl*/ false)) {
8339        case Ovl_Match:
8340          Redeclaration = true;
8341          break;
8342  
8343        case Ovl_NonFunction:
8344          Redeclaration = true;
8345          break;
8346  
8347        case Ovl_Overload:
8348          Redeclaration = false;
8349          break;
8350        }
8351  
8352        if (!getLangOpts().CPlusPlus && !NewFD->hasAttr<OverloadableAttr>()) {
8353          // If a function name is overloadable in C, then every function
8354          // with that name must be marked "overloadable".
8355          Diag(NewFD->getLocation(), diag::err_attribute_overloadable_missing)
8356            << Redeclaration << NewFD;
8357          NamedDecl *OverloadedDecl = nullptr;
8358          if (Redeclaration)
8359            OverloadedDecl = OldDecl;
8360          else if (!Previous.empty())
8361            OverloadedDecl = Previous.getRepresentativeDecl();
8362          if (OverloadedDecl)
8363            Diag(OverloadedDecl->getLocation(),
8364                 diag::note_attribute_overloadable_prev_overload);
8365          NewFD->addAttr(OverloadableAttr::CreateImplicit(Context));
8366        }
8367      }
8368    }
8369  
8370    // Check for a previous extern "C" declaration with this name.
8371    if (!Redeclaration &&
8372        checkForConflictWithNonVisibleExternC(*this, NewFD, Previous)) {
8373      if (!Previous.empty()) {
8374        // This is an extern "C" declaration with the same name as a previous
8375        // declaration, and thus redeclares that entity...
8376        Redeclaration = true;
8377        OldDecl = Previous.getFoundDecl();
8378        MergeTypeWithPrevious = false;
8379  
8380        // ... except in the presence of __attribute__((overloadable)).
8381        if (OldDecl->hasAttr<OverloadableAttr>()) {
8382          if (!getLangOpts().CPlusPlus && !NewFD->hasAttr<OverloadableAttr>()) {
8383            Diag(NewFD->getLocation(), diag::err_attribute_overloadable_missing)
8384              << Redeclaration << NewFD;
8385            Diag(Previous.getFoundDecl()->getLocation(),
8386                 diag::note_attribute_overloadable_prev_overload);
8387            NewFD->addAttr(OverloadableAttr::CreateImplicit(Context));
8388          }
8389          if (IsOverload(NewFD, cast<FunctionDecl>(OldDecl), false)) {
8390            Redeclaration = false;
8391            OldDecl = nullptr;
8392          }
8393        }
8394      }
8395    }
8396  
8397    // C++11 [dcl.constexpr]p8:
8398    //   A constexpr specifier for a non-static member function that is not
8399    //   a constructor declares that member function to be const.
8400    //
8401    // This needs to be delayed until we know whether this is an out-of-line
8402    // definition of a static member function.
8403    //
8404    // This rule is not present in C++1y, so we produce a backwards
8405    // compatibility warning whenever it happens in C++11.
8406    CXXMethodDecl *MD = dyn_cast<CXXMethodDecl>(NewFD);
8407    if (!getLangOpts().CPlusPlus14 && MD && MD->isConstexpr() &&
8408        !MD->isStatic() && !isa<CXXConstructorDecl>(MD) &&
8409        (MD->getTypeQualifiers() & Qualifiers::Const) == 0) {
8410      CXXMethodDecl *OldMD = nullptr;
8411      if (OldDecl)
8412        OldMD = dyn_cast_or_null<CXXMethodDecl>(OldDecl->getAsFunction());
8413      if (!OldMD || !OldMD->isStatic()) {
8414        const FunctionProtoType *FPT =
8415          MD->getType()->castAs<FunctionProtoType>();
8416        FunctionProtoType::ExtProtoInfo EPI = FPT->getExtProtoInfo();
8417        EPI.TypeQuals |= Qualifiers::Const;
8418        MD->setType(Context.getFunctionType(FPT->getReturnType(),
8419                                            FPT->getParamTypes(), EPI));
8420  
8421        // Warn that we did this, if we're not performing template instantiation.
8422        // In that case, we'll have warned already when the template was defined.
8423        if (ActiveTemplateInstantiations.empty()) {
8424          SourceLocation AddConstLoc;
8425          if (FunctionTypeLoc FTL = MD->getTypeSourceInfo()->getTypeLoc()
8426                  .IgnoreParens().getAs<FunctionTypeLoc>())
8427            AddConstLoc = getLocForEndOfToken(FTL.getRParenLoc());
8428  
8429          Diag(MD->getLocation(), diag::warn_cxx14_compat_constexpr_not_const)
8430            << FixItHint::CreateInsertion(AddConstLoc, " const");
8431        }
8432      }
8433    }
8434  
8435    if (Redeclaration) {
8436      // NewFD and OldDecl represent declarations that need to be
8437      // merged.
8438      if (MergeFunctionDecl(NewFD, OldDecl, S, MergeTypeWithPrevious)) {
8439        NewFD->setInvalidDecl();
8440        return Redeclaration;
8441      }
8442  
8443      Previous.clear();
8444      Previous.addDecl(OldDecl);
8445  
8446      if (FunctionTemplateDecl *OldTemplateDecl
8447                                    = dyn_cast<FunctionTemplateDecl>(OldDecl)) {
8448        NewFD->setPreviousDeclaration(OldTemplateDecl->getTemplatedDecl());
8449        FunctionTemplateDecl *NewTemplateDecl
8450          = NewFD->getDescribedFunctionTemplate();
8451        assert(NewTemplateDecl && "Template/non-template mismatch");
8452        if (CXXMethodDecl *Method
8453              = dyn_cast<CXXMethodDecl>(NewTemplateDecl->getTemplatedDecl())) {
8454          Method->setAccess(OldTemplateDecl->getAccess());
8455          NewTemplateDecl->setAccess(OldTemplateDecl->getAccess());
8456        }
8457  
8458        // If this is an explicit specialization of a member that is a function
8459        // template, mark it as a member specialization.
8460        if (IsExplicitSpecialization &&
8461            NewTemplateDecl->getInstantiatedFromMemberTemplate()) {
8462          NewTemplateDecl->setMemberSpecialization();
8463          assert(OldTemplateDecl->isMemberSpecialization());
8464        }
8465  
8466      } else {
8467        // This needs to happen first so that 'inline' propagates.
8468        NewFD->setPreviousDeclaration(cast<FunctionDecl>(OldDecl));
8469  
8470        if (isa<CXXMethodDecl>(NewFD))
8471          NewFD->setAccess(OldDecl->getAccess());
8472      }
8473    }
8474  
8475    // Semantic checking for this function declaration (in isolation).
8476  
8477    if (getLangOpts().CPlusPlus) {
8478      // C++-specific checks.
8479      if (CXXConstructorDecl *Constructor = dyn_cast<CXXConstructorDecl>(NewFD)) {
8480        CheckConstructor(Constructor);
8481      } else if (CXXDestructorDecl *Destructor =
8482                  dyn_cast<CXXDestructorDecl>(NewFD)) {
8483        CXXRecordDecl *Record = Destructor->getParent();
8484        QualType ClassType = Context.getTypeDeclType(Record);
8485  
8486        // FIXME: Shouldn't we be able to perform this check even when the class
8487        // type is dependent? Both gcc and edg can handle that.
8488        if (!ClassType->isDependentType()) {
8489          DeclarationName Name
8490            = Context.DeclarationNames.getCXXDestructorName(
8491                                          Context.getCanonicalType(ClassType));
8492          if (NewFD->getDeclName() != Name) {
8493            Diag(NewFD->getLocation(), diag::err_destructor_name);
8494            NewFD->setInvalidDecl();
8495            return Redeclaration;
8496          }
8497        }
8498      } else if (CXXConversionDecl *Conversion
8499                 = dyn_cast<CXXConversionDecl>(NewFD)) {
8500        ActOnConversionDeclarator(Conversion);
8501      }
8502  
8503      // Find any virtual functions that this function overrides.
8504      if (CXXMethodDecl *Method = dyn_cast<CXXMethodDecl>(NewFD)) {
8505        if (!Method->isFunctionTemplateSpecialization() &&
8506            !Method->getDescribedFunctionTemplate() &&
8507            Method->isCanonicalDecl()) {
8508          if (AddOverriddenMethods(Method->getParent(), Method)) {
8509            // If the function was marked as "static", we have a problem.
8510            if (NewFD->getStorageClass() == SC_Static) {
8511              ReportOverrides(*this, diag::err_static_overrides_virtual, Method);
8512            }
8513          }
8514        }
8515  
8516        if (Method->isStatic())
8517          checkThisInStaticMemberFunctionType(Method);
8518      }
8519  
8520      // Extra checking for C++ overloaded operators (C++ [over.oper]).
8521      if (NewFD->isOverloadedOperator() &&
8522          CheckOverloadedOperatorDeclaration(NewFD)) {
8523        NewFD->setInvalidDecl();
8524        return Redeclaration;
8525      }
8526  
8527      // Extra checking for C++0x literal operators (C++0x [over.literal]).
8528      if (NewFD->getLiteralIdentifier() &&
8529          CheckLiteralOperatorDeclaration(NewFD)) {
8530        NewFD->setInvalidDecl();
8531        return Redeclaration;
8532      }
8533  
8534      // In C++, check default arguments now that we have merged decls. Unless
8535      // the lexical context is the class, because in this case this is done
8536      // during delayed parsing anyway.
8537      if (!CurContext->isRecord())
8538        CheckCXXDefaultArguments(NewFD);
8539  
8540      // If this function declares a builtin function, check the type of this
8541      // declaration against the expected type for the builtin.
8542      if (unsigned BuiltinID = NewFD->getBuiltinID()) {
8543        ASTContext::GetBuiltinTypeError Error;
8544        LookupPredefedObjCSuperType(*this, S, NewFD->getIdentifier());
8545        QualType T = Context.GetBuiltinType(BuiltinID, Error);
8546        if (!T.isNull() && !Context.hasSameType(T, NewFD->getType())) {
8547          // The type of this function differs from the type of the builtin,
8548          // so forget about the builtin entirely.
8549          Context.BuiltinInfo.forgetBuiltin(BuiltinID, Context.Idents);
8550        }
8551      }
8552  
8553      // If this function is declared as being extern "C", then check to see if
8554      // the function returns a UDT (class, struct, or union type) that is not C
8555      // compatible, and if it does, warn the user.
8556      // But, issue any diagnostic on the first declaration only.
8557      if (Previous.empty() && NewFD->isExternC()) {
8558        QualType R = NewFD->getReturnType();
8559        if (R->isIncompleteType() && !R->isVoidType())
8560          Diag(NewFD->getLocation(), diag::warn_return_value_udt_incomplete)
8561              << NewFD << R;
8562        else if (!R.isPODType(Context) && !R->isVoidType() &&
8563                 !R->isObjCObjectPointerType())
8564          Diag(NewFD->getLocation(), diag::warn_return_value_udt) << NewFD << R;
8565      }
8566    }
8567    return Redeclaration;
8568  }
8569  
CheckMain(FunctionDecl * FD,const DeclSpec & DS)8570  void Sema::CheckMain(FunctionDecl* FD, const DeclSpec& DS) {
8571    // C++11 [basic.start.main]p3:
8572    //   A program that [...] declares main to be inline, static or
8573    //   constexpr is ill-formed.
8574    // C11 6.7.4p4:  In a hosted environment, no function specifier(s) shall
8575    //   appear in a declaration of main.
8576    // static main is not an error under C99, but we should warn about it.
8577    // We accept _Noreturn main as an extension.
8578    if (FD->getStorageClass() == SC_Static)
8579      Diag(DS.getStorageClassSpecLoc(), getLangOpts().CPlusPlus
8580           ? diag::err_static_main : diag::warn_static_main)
8581        << FixItHint::CreateRemoval(DS.getStorageClassSpecLoc());
8582    if (FD->isInlineSpecified())
8583      Diag(DS.getInlineSpecLoc(), diag::err_inline_main)
8584        << FixItHint::CreateRemoval(DS.getInlineSpecLoc());
8585    if (DS.isNoreturnSpecified()) {
8586      SourceLocation NoreturnLoc = DS.getNoreturnSpecLoc();
8587      SourceRange NoreturnRange(NoreturnLoc, getLocForEndOfToken(NoreturnLoc));
8588      Diag(NoreturnLoc, diag::ext_noreturn_main);
8589      Diag(NoreturnLoc, diag::note_main_remove_noreturn)
8590        << FixItHint::CreateRemoval(NoreturnRange);
8591    }
8592    if (FD->isConstexpr()) {
8593      Diag(DS.getConstexprSpecLoc(), diag::err_constexpr_main)
8594        << FixItHint::CreateRemoval(DS.getConstexprSpecLoc());
8595      FD->setConstexpr(false);
8596    }
8597  
8598    if (getLangOpts().OpenCL) {
8599      Diag(FD->getLocation(), diag::err_opencl_no_main)
8600          << FD->hasAttr<OpenCLKernelAttr>();
8601      FD->setInvalidDecl();
8602      return;
8603    }
8604  
8605    QualType T = FD->getType();
8606    assert(T->isFunctionType() && "function decl is not of function type");
8607    const FunctionType* FT = T->castAs<FunctionType>();
8608  
8609    if (getLangOpts().GNUMode && !getLangOpts().CPlusPlus) {
8610      // In C with GNU extensions we allow main() to have non-integer return
8611      // type, but we should warn about the extension, and we disable the
8612      // implicit-return-zero rule.
8613  
8614      // GCC in C mode accepts qualified 'int'.
8615      if (Context.hasSameUnqualifiedType(FT->getReturnType(), Context.IntTy))
8616        FD->setHasImplicitReturnZero(true);
8617      else {
8618        Diag(FD->getTypeSpecStartLoc(), diag::ext_main_returns_nonint);
8619        SourceRange RTRange = FD->getReturnTypeSourceRange();
8620        if (RTRange.isValid())
8621          Diag(RTRange.getBegin(), diag::note_main_change_return_type)
8622              << FixItHint::CreateReplacement(RTRange, "int");
8623      }
8624    } else {
8625      // In C and C++, main magically returns 0 if you fall off the end;
8626      // set the flag which tells us that.
8627      // This is C++ [basic.start.main]p5 and C99 5.1.2.2.3.
8628  
8629      // All the standards say that main() should return 'int'.
8630      if (Context.hasSameType(FT->getReturnType(), Context.IntTy))
8631        FD->setHasImplicitReturnZero(true);
8632      else {
8633        // Otherwise, this is just a flat-out error.
8634        SourceRange RTRange = FD->getReturnTypeSourceRange();
8635        Diag(FD->getTypeSpecStartLoc(), diag::err_main_returns_nonint)
8636            << (RTRange.isValid() ? FixItHint::CreateReplacement(RTRange, "int")
8637                                  : FixItHint());
8638        FD->setInvalidDecl(true);
8639      }
8640    }
8641  
8642    // Treat protoless main() as nullary.
8643    if (isa<FunctionNoProtoType>(FT)) return;
8644  
8645    const FunctionProtoType* FTP = cast<const FunctionProtoType>(FT);
8646    unsigned nparams = FTP->getNumParams();
8647    assert(FD->getNumParams() == nparams);
8648  
8649    bool HasExtraParameters = (nparams > 3);
8650  
8651    if (FTP->isVariadic()) {
8652      Diag(FD->getLocation(), diag::ext_variadic_main);
8653      // FIXME: if we had information about the location of the ellipsis, we
8654      // could add a FixIt hint to remove it as a parameter.
8655    }
8656  
8657    // Darwin passes an undocumented fourth argument of type char**.  If
8658    // other platforms start sprouting these, the logic below will start
8659    // getting shifty.
8660    if (nparams == 4 && Context.getTargetInfo().getTriple().isOSDarwin())
8661      HasExtraParameters = false;
8662  
8663    if (HasExtraParameters) {
8664      Diag(FD->getLocation(), diag::err_main_surplus_args) << nparams;
8665      FD->setInvalidDecl(true);
8666      nparams = 3;
8667    }
8668  
8669    // FIXME: a lot of the following diagnostics would be improved
8670    // if we had some location information about types.
8671  
8672    QualType CharPP =
8673      Context.getPointerType(Context.getPointerType(Context.CharTy));
8674    QualType Expected[] = { Context.IntTy, CharPP, CharPP, CharPP };
8675  
8676    for (unsigned i = 0; i < nparams; ++i) {
8677      QualType AT = FTP->getParamType(i);
8678  
8679      bool mismatch = true;
8680  
8681      if (Context.hasSameUnqualifiedType(AT, Expected[i]))
8682        mismatch = false;
8683      else if (Expected[i] == CharPP) {
8684        // As an extension, the following forms are okay:
8685        //   char const **
8686        //   char const * const *
8687        //   char * const *
8688  
8689        QualifierCollector qs;
8690        const PointerType* PT;
8691        if ((PT = qs.strip(AT)->getAs<PointerType>()) &&
8692            (PT = qs.strip(PT->getPointeeType())->getAs<PointerType>()) &&
8693            Context.hasSameType(QualType(qs.strip(PT->getPointeeType()), 0),
8694                                Context.CharTy)) {
8695          qs.removeConst();
8696          mismatch = !qs.empty();
8697        }
8698      }
8699  
8700      if (mismatch) {
8701        Diag(FD->getLocation(), diag::err_main_arg_wrong) << i << Expected[i];
8702        // TODO: suggest replacing given type with expected type
8703        FD->setInvalidDecl(true);
8704      }
8705    }
8706  
8707    if (nparams == 1 && !FD->isInvalidDecl()) {
8708      Diag(FD->getLocation(), diag::warn_main_one_arg);
8709    }
8710  
8711    if (!FD->isInvalidDecl() && FD->getDescribedFunctionTemplate()) {
8712      Diag(FD->getLocation(), diag::err_mainlike_template_decl) << FD;
8713      FD->setInvalidDecl();
8714    }
8715  }
8716  
CheckMSVCRTEntryPoint(FunctionDecl * FD)8717  void Sema::CheckMSVCRTEntryPoint(FunctionDecl *FD) {
8718    QualType T = FD->getType();
8719    assert(T->isFunctionType() && "function decl is not of function type");
8720    const FunctionType *FT = T->castAs<FunctionType>();
8721  
8722    // Set an implicit return of 'zero' if the function can return some integral,
8723    // enumeration, pointer or nullptr type.
8724    if (FT->getReturnType()->isIntegralOrEnumerationType() ||
8725        FT->getReturnType()->isAnyPointerType() ||
8726        FT->getReturnType()->isNullPtrType())
8727      // DllMain is exempt because a return value of zero means it failed.
8728      if (FD->getName() != "DllMain")
8729        FD->setHasImplicitReturnZero(true);
8730  
8731    if (!FD->isInvalidDecl() && FD->getDescribedFunctionTemplate()) {
8732      Diag(FD->getLocation(), diag::err_mainlike_template_decl) << FD;
8733      FD->setInvalidDecl();
8734    }
8735  }
8736  
CheckForConstantInitializer(Expr * Init,QualType DclT)8737  bool Sema::CheckForConstantInitializer(Expr *Init, QualType DclT) {
8738    // FIXME: Need strict checking.  In C89, we need to check for
8739    // any assignment, increment, decrement, function-calls, or
8740    // commas outside of a sizeof.  In C99, it's the same list,
8741    // except that the aforementioned are allowed in unevaluated
8742    // expressions.  Everything else falls under the
8743    // "may accept other forms of constant expressions" exception.
8744    // (We never end up here for C++, so the constant expression
8745    // rules there don't matter.)
8746    const Expr *Culprit;
8747    if (Init->isConstantInitializer(Context, false, &Culprit))
8748      return false;
8749    Diag(Culprit->getExprLoc(), diag::err_init_element_not_constant)
8750      << Culprit->getSourceRange();
8751    return true;
8752  }
8753  
8754  namespace {
8755    // Visits an initialization expression to see if OrigDecl is evaluated in
8756    // its own initialization and throws a warning if it does.
8757    class SelfReferenceChecker
8758        : public EvaluatedExprVisitor<SelfReferenceChecker> {
8759      Sema &S;
8760      Decl *OrigDecl;
8761      bool isRecordType;
8762      bool isPODType;
8763      bool isReferenceType;
8764  
8765      bool isInitList;
8766      llvm::SmallVector<unsigned, 4> InitFieldIndex;
8767    public:
8768      typedef EvaluatedExprVisitor<SelfReferenceChecker> Inherited;
8769  
SelfReferenceChecker(Sema & S,Decl * OrigDecl)8770      SelfReferenceChecker(Sema &S, Decl *OrigDecl) : Inherited(S.Context),
8771                                                      S(S), OrigDecl(OrigDecl) {
8772        isPODType = false;
8773        isRecordType = false;
8774        isReferenceType = false;
8775        isInitList = false;
8776        if (ValueDecl *VD = dyn_cast<ValueDecl>(OrigDecl)) {
8777          isPODType = VD->getType().isPODType(S.Context);
8778          isRecordType = VD->getType()->isRecordType();
8779          isReferenceType = VD->getType()->isReferenceType();
8780        }
8781      }
8782  
8783      // For most expressions, just call the visitor.  For initializer lists,
8784      // track the index of the field being initialized since fields are
8785      // initialized in order allowing use of previously initialized fields.
CheckExpr(Expr * E)8786      void CheckExpr(Expr *E) {
8787        InitListExpr *InitList = dyn_cast<InitListExpr>(E);
8788        if (!InitList) {
8789          Visit(E);
8790          return;
8791        }
8792  
8793        // Track and increment the index here.
8794        isInitList = true;
8795        InitFieldIndex.push_back(0);
8796        for (auto Child : InitList->children()) {
8797          CheckExpr(cast<Expr>(Child));
8798          ++InitFieldIndex.back();
8799        }
8800        InitFieldIndex.pop_back();
8801      }
8802  
8803      // Returns true if MemberExpr is checked and no futher checking is needed.
8804      // Returns false if additional checking is required.
CheckInitListMemberExpr(MemberExpr * E,bool CheckReference)8805      bool CheckInitListMemberExpr(MemberExpr *E, bool CheckReference) {
8806        llvm::SmallVector<FieldDecl*, 4> Fields;
8807        Expr *Base = E;
8808        bool ReferenceField = false;
8809  
8810        // Get the field memebers used.
8811        while (MemberExpr *ME = dyn_cast<MemberExpr>(Base)) {
8812          FieldDecl *FD = dyn_cast<FieldDecl>(ME->getMemberDecl());
8813          if (!FD)
8814            return false;
8815          Fields.push_back(FD);
8816          if (FD->getType()->isReferenceType())
8817            ReferenceField = true;
8818          Base = ME->getBase()->IgnoreParenImpCasts();
8819        }
8820  
8821        // Keep checking only if the base Decl is the same.
8822        DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(Base);
8823        if (!DRE || DRE->getDecl() != OrigDecl)
8824          return false;
8825  
8826        // A reference field can be bound to an unininitialized field.
8827        if (CheckReference && !ReferenceField)
8828          return true;
8829  
8830        // Convert FieldDecls to their index number.
8831        llvm::SmallVector<unsigned, 4> UsedFieldIndex;
8832        for (const FieldDecl *I : llvm::reverse(Fields))
8833          UsedFieldIndex.push_back(I->getFieldIndex());
8834  
8835        // See if a warning is needed by checking the first difference in index
8836        // numbers.  If field being used has index less than the field being
8837        // initialized, then the use is safe.
8838        for (auto UsedIter = UsedFieldIndex.begin(),
8839                  UsedEnd = UsedFieldIndex.end(),
8840                  OrigIter = InitFieldIndex.begin(),
8841                  OrigEnd = InitFieldIndex.end();
8842             UsedIter != UsedEnd && OrigIter != OrigEnd; ++UsedIter, ++OrigIter) {
8843          if (*UsedIter < *OrigIter)
8844            return true;
8845          if (*UsedIter > *OrigIter)
8846            break;
8847        }
8848  
8849        // TODO: Add a different warning which will print the field names.
8850        HandleDeclRefExpr(DRE);
8851        return true;
8852      }
8853  
8854      // For most expressions, the cast is directly above the DeclRefExpr.
8855      // For conditional operators, the cast can be outside the conditional
8856      // operator if both expressions are DeclRefExpr's.
HandleValue(Expr * E)8857      void HandleValue(Expr *E) {
8858        E = E->IgnoreParens();
8859        if (DeclRefExpr* DRE = dyn_cast<DeclRefExpr>(E)) {
8860          HandleDeclRefExpr(DRE);
8861          return;
8862        }
8863  
8864        if (ConditionalOperator *CO = dyn_cast<ConditionalOperator>(E)) {
8865          Visit(CO->getCond());
8866          HandleValue(CO->getTrueExpr());
8867          HandleValue(CO->getFalseExpr());
8868          return;
8869        }
8870  
8871        if (BinaryConditionalOperator *BCO =
8872                dyn_cast<BinaryConditionalOperator>(E)) {
8873          Visit(BCO->getCond());
8874          HandleValue(BCO->getFalseExpr());
8875          return;
8876        }
8877  
8878        if (OpaqueValueExpr *OVE = dyn_cast<OpaqueValueExpr>(E)) {
8879          HandleValue(OVE->getSourceExpr());
8880          return;
8881        }
8882  
8883        if (BinaryOperator *BO = dyn_cast<BinaryOperator>(E)) {
8884          if (BO->getOpcode() == BO_Comma) {
8885            Visit(BO->getLHS());
8886            HandleValue(BO->getRHS());
8887            return;
8888          }
8889        }
8890  
8891        if (isa<MemberExpr>(E)) {
8892          if (isInitList) {
8893            if (CheckInitListMemberExpr(cast<MemberExpr>(E),
8894                                        false /*CheckReference*/))
8895              return;
8896          }
8897  
8898          Expr *Base = E->IgnoreParenImpCasts();
8899          while (MemberExpr *ME = dyn_cast<MemberExpr>(Base)) {
8900            // Check for static member variables and don't warn on them.
8901            if (!isa<FieldDecl>(ME->getMemberDecl()))
8902              return;
8903            Base = ME->getBase()->IgnoreParenImpCasts();
8904          }
8905          if (DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(Base))
8906            HandleDeclRefExpr(DRE);
8907          return;
8908        }
8909  
8910        Visit(E);
8911      }
8912  
8913      // Reference types not handled in HandleValue are handled here since all
8914      // uses of references are bad, not just r-value uses.
VisitDeclRefExpr(DeclRefExpr * E)8915      void VisitDeclRefExpr(DeclRefExpr *E) {
8916        if (isReferenceType)
8917          HandleDeclRefExpr(E);
8918      }
8919  
VisitImplicitCastExpr(ImplicitCastExpr * E)8920      void VisitImplicitCastExpr(ImplicitCastExpr *E) {
8921        if (E->getCastKind() == CK_LValueToRValue) {
8922          HandleValue(E->getSubExpr());
8923          return;
8924        }
8925  
8926        Inherited::VisitImplicitCastExpr(E);
8927      }
8928  
VisitMemberExpr(MemberExpr * E)8929      void VisitMemberExpr(MemberExpr *E) {
8930        if (isInitList) {
8931          if (CheckInitListMemberExpr(E, true /*CheckReference*/))
8932            return;
8933        }
8934  
8935        // Don't warn on arrays since they can be treated as pointers.
8936        if (E->getType()->canDecayToPointerType()) return;
8937  
8938        // Warn when a non-static method call is followed by non-static member
8939        // field accesses, which is followed by a DeclRefExpr.
8940        CXXMethodDecl *MD = dyn_cast<CXXMethodDecl>(E->getMemberDecl());
8941        bool Warn = (MD && !MD->isStatic());
8942        Expr *Base = E->getBase()->IgnoreParenImpCasts();
8943        while (MemberExpr *ME = dyn_cast<MemberExpr>(Base)) {
8944          if (!isa<FieldDecl>(ME->getMemberDecl()))
8945            Warn = false;
8946          Base = ME->getBase()->IgnoreParenImpCasts();
8947        }
8948  
8949        if (DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(Base)) {
8950          if (Warn)
8951            HandleDeclRefExpr(DRE);
8952          return;
8953        }
8954  
8955        // The base of a MemberExpr is not a MemberExpr or a DeclRefExpr.
8956        // Visit that expression.
8957        Visit(Base);
8958      }
8959  
VisitCXXOperatorCallExpr(CXXOperatorCallExpr * E)8960      void VisitCXXOperatorCallExpr(CXXOperatorCallExpr *E) {
8961        Expr *Callee = E->getCallee();
8962  
8963        if (isa<UnresolvedLookupExpr>(Callee))
8964          return Inherited::VisitCXXOperatorCallExpr(E);
8965  
8966        Visit(Callee);
8967        for (auto Arg: E->arguments())
8968          HandleValue(Arg->IgnoreParenImpCasts());
8969      }
8970  
VisitUnaryOperator(UnaryOperator * E)8971      void VisitUnaryOperator(UnaryOperator *E) {
8972        // For POD record types, addresses of its own members are well-defined.
8973        if (E->getOpcode() == UO_AddrOf && isRecordType &&
8974            isa<MemberExpr>(E->getSubExpr()->IgnoreParens())) {
8975          if (!isPODType)
8976            HandleValue(E->getSubExpr());
8977          return;
8978        }
8979  
8980        if (E->isIncrementDecrementOp()) {
8981          HandleValue(E->getSubExpr());
8982          return;
8983        }
8984  
8985        Inherited::VisitUnaryOperator(E);
8986      }
8987  
VisitObjCMessageExpr(ObjCMessageExpr * E)8988      void VisitObjCMessageExpr(ObjCMessageExpr *E) { return; }
8989  
VisitCXXConstructExpr(CXXConstructExpr * E)8990      void VisitCXXConstructExpr(CXXConstructExpr *E) {
8991        if (E->getConstructor()->isCopyConstructor()) {
8992          Expr *ArgExpr = E->getArg(0);
8993          if (InitListExpr *ILE = dyn_cast<InitListExpr>(ArgExpr))
8994            if (ILE->getNumInits() == 1)
8995              ArgExpr = ILE->getInit(0);
8996          if (ImplicitCastExpr *ICE = dyn_cast<ImplicitCastExpr>(ArgExpr))
8997            if (ICE->getCastKind() == CK_NoOp)
8998              ArgExpr = ICE->getSubExpr();
8999          HandleValue(ArgExpr);
9000          return;
9001        }
9002        Inherited::VisitCXXConstructExpr(E);
9003      }
9004  
VisitCallExpr(CallExpr * E)9005      void VisitCallExpr(CallExpr *E) {
9006        // Treat std::move as a use.
9007        if (E->getNumArgs() == 1) {
9008          if (FunctionDecl *FD = E->getDirectCallee()) {
9009            if (FD->isInStdNamespace() && FD->getIdentifier() &&
9010                FD->getIdentifier()->isStr("move")) {
9011              HandleValue(E->getArg(0));
9012              return;
9013            }
9014          }
9015        }
9016  
9017        Inherited::VisitCallExpr(E);
9018      }
9019  
VisitBinaryOperator(BinaryOperator * E)9020      void VisitBinaryOperator(BinaryOperator *E) {
9021        if (E->isCompoundAssignmentOp()) {
9022          HandleValue(E->getLHS());
9023          Visit(E->getRHS());
9024          return;
9025        }
9026  
9027        Inherited::VisitBinaryOperator(E);
9028      }
9029  
9030      // A custom visitor for BinaryConditionalOperator is needed because the
9031      // regular visitor would check the condition and true expression separately
9032      // but both point to the same place giving duplicate diagnostics.
VisitBinaryConditionalOperator(BinaryConditionalOperator * E)9033      void VisitBinaryConditionalOperator(BinaryConditionalOperator *E) {
9034        Visit(E->getCond());
9035        Visit(E->getFalseExpr());
9036      }
9037  
HandleDeclRefExpr(DeclRefExpr * DRE)9038      void HandleDeclRefExpr(DeclRefExpr *DRE) {
9039        Decl* ReferenceDecl = DRE->getDecl();
9040        if (OrigDecl != ReferenceDecl) return;
9041        unsigned diag;
9042        if (isReferenceType) {
9043          diag = diag::warn_uninit_self_reference_in_reference_init;
9044        } else if (cast<VarDecl>(OrigDecl)->isStaticLocal()) {
9045          diag = diag::warn_static_self_reference_in_init;
9046        } else if (isa<TranslationUnitDecl>(OrigDecl->getDeclContext()) ||
9047                   isa<NamespaceDecl>(OrigDecl->getDeclContext()) ||
9048                   DRE->getDecl()->getType()->isRecordType()) {
9049          diag = diag::warn_uninit_self_reference_in_init;
9050        } else {
9051          // Local variables will be handled by the CFG analysis.
9052          return;
9053        }
9054  
9055        S.DiagRuntimeBehavior(DRE->getLocStart(), DRE,
9056                              S.PDiag(diag)
9057                                << DRE->getNameInfo().getName()
9058                                << OrigDecl->getLocation()
9059                                << DRE->getSourceRange());
9060      }
9061    };
9062  
9063    /// CheckSelfReference - Warns if OrigDecl is used in expression E.
CheckSelfReference(Sema & S,Decl * OrigDecl,Expr * E,bool DirectInit)9064    static void CheckSelfReference(Sema &S, Decl* OrigDecl, Expr *E,
9065                                   bool DirectInit) {
9066      // Parameters arguments are occassionially constructed with itself,
9067      // for instance, in recursive functions.  Skip them.
9068      if (isa<ParmVarDecl>(OrigDecl))
9069        return;
9070  
9071      E = E->IgnoreParens();
9072  
9073      // Skip checking T a = a where T is not a record or reference type.
9074      // Doing so is a way to silence uninitialized warnings.
9075      if (!DirectInit && !cast<VarDecl>(OrigDecl)->getType()->isRecordType())
9076        if (ImplicitCastExpr *ICE = dyn_cast<ImplicitCastExpr>(E))
9077          if (ICE->getCastKind() == CK_LValueToRValue)
9078            if (DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(ICE->getSubExpr()))
9079              if (DRE->getDecl() == OrigDecl)
9080                return;
9081  
9082      SelfReferenceChecker(S, OrigDecl).CheckExpr(E);
9083    }
9084  }
9085  
deduceVarTypeFromInitializer(VarDecl * VDecl,DeclarationName Name,QualType Type,TypeSourceInfo * TSI,SourceRange Range,bool DirectInit,Expr * Init)9086  QualType Sema::deduceVarTypeFromInitializer(VarDecl *VDecl,
9087                                              DeclarationName Name, QualType Type,
9088                                              TypeSourceInfo *TSI,
9089                                              SourceRange Range, bool DirectInit,
9090                                              Expr *Init) {
9091    bool IsInitCapture = !VDecl;
9092    assert((!VDecl || !VDecl->isInitCapture()) &&
9093           "init captures are expected to be deduced prior to initialization");
9094  
9095    ArrayRef<Expr *> DeduceInits = Init;
9096    if (DirectInit) {
9097      if (auto *PL = dyn_cast<ParenListExpr>(Init))
9098        DeduceInits = PL->exprs();
9099      else if (auto *IL = dyn_cast<InitListExpr>(Init))
9100        DeduceInits = IL->inits();
9101    }
9102  
9103    // Deduction only works if we have exactly one source expression.
9104    if (DeduceInits.empty()) {
9105      // It isn't possible to write this directly, but it is possible to
9106      // end up in this situation with "auto x(some_pack...);"
9107      Diag(Init->getLocStart(), IsInitCapture
9108                                    ? diag::err_init_capture_no_expression
9109                                    : diag::err_auto_var_init_no_expression)
9110          << Name << Type << Range;
9111      return QualType();
9112    }
9113  
9114    if (DeduceInits.size() > 1) {
9115      Diag(DeduceInits[1]->getLocStart(),
9116           IsInitCapture ? diag::err_init_capture_multiple_expressions
9117                         : diag::err_auto_var_init_multiple_expressions)
9118          << Name << Type << Range;
9119      return QualType();
9120    }
9121  
9122    Expr *DeduceInit = DeduceInits[0];
9123    if (DirectInit && isa<InitListExpr>(DeduceInit)) {
9124      Diag(Init->getLocStart(), IsInitCapture
9125                                    ? diag::err_init_capture_paren_braces
9126                                    : diag::err_auto_var_init_paren_braces)
9127          << isa<InitListExpr>(Init) << Name << Type << Range;
9128      return QualType();
9129    }
9130  
9131    // Expressions default to 'id' when we're in a debugger.
9132    bool DefaultedAnyToId = false;
9133    if (getLangOpts().DebuggerCastResultToId &&
9134        Init->getType() == Context.UnknownAnyTy && !IsInitCapture) {
9135      ExprResult Result = forceUnknownAnyToType(Init, Context.getObjCIdType());
9136      if (Result.isInvalid()) {
9137        return QualType();
9138      }
9139      Init = Result.get();
9140      DefaultedAnyToId = true;
9141    }
9142  
9143    QualType DeducedType;
9144    if (DeduceAutoType(TSI, DeduceInit, DeducedType) == DAR_Failed) {
9145      if (!IsInitCapture)
9146        DiagnoseAutoDeductionFailure(VDecl, DeduceInit);
9147      else if (isa<InitListExpr>(Init))
9148        Diag(Range.getBegin(),
9149             diag::err_init_capture_deduction_failure_from_init_list)
9150            << Name
9151            << (DeduceInit->getType().isNull() ? TSI->getType()
9152                                               : DeduceInit->getType())
9153            << DeduceInit->getSourceRange();
9154      else
9155        Diag(Range.getBegin(), diag::err_init_capture_deduction_failure)
9156            << Name << TSI->getType()
9157            << (DeduceInit->getType().isNull() ? TSI->getType()
9158                                               : DeduceInit->getType())
9159            << DeduceInit->getSourceRange();
9160    }
9161  
9162    // Warn if we deduced 'id'. 'auto' usually implies type-safety, but using
9163    // 'id' instead of a specific object type prevents most of our usual
9164    // checks.
9165    // We only want to warn outside of template instantiations, though:
9166    // inside a template, the 'id' could have come from a parameter.
9167    if (ActiveTemplateInstantiations.empty() && !DefaultedAnyToId &&
9168        !IsInitCapture && !DeducedType.isNull() && DeducedType->isObjCIdType()) {
9169      SourceLocation Loc = TSI->getTypeLoc().getBeginLoc();
9170      Diag(Loc, diag::warn_auto_var_is_id) << Name << Range;
9171    }
9172  
9173    return DeducedType;
9174  }
9175  
9176  /// AddInitializerToDecl - Adds the initializer Init to the
9177  /// declaration dcl. If DirectInit is true, this is C++ direct
9178  /// initialization rather than copy initialization.
AddInitializerToDecl(Decl * RealDecl,Expr * Init,bool DirectInit,bool TypeMayContainAuto)9179  void Sema::AddInitializerToDecl(Decl *RealDecl, Expr *Init,
9180                                  bool DirectInit, bool TypeMayContainAuto) {
9181    // If there is no declaration, there was an error parsing it.  Just ignore
9182    // the initializer.
9183    if (!RealDecl || RealDecl->isInvalidDecl()) {
9184      CorrectDelayedTyposInExpr(Init, dyn_cast_or_null<VarDecl>(RealDecl));
9185      return;
9186    }
9187  
9188    if (CXXMethodDecl *Method = dyn_cast<CXXMethodDecl>(RealDecl)) {
9189      // Pure-specifiers are handled in ActOnPureSpecifier.
9190      Diag(Method->getLocation(), diag::err_member_function_initialization)
9191        << Method->getDeclName() << Init->getSourceRange();
9192      Method->setInvalidDecl();
9193      return;
9194    }
9195  
9196    VarDecl *VDecl = dyn_cast<VarDecl>(RealDecl);
9197    if (!VDecl) {
9198      assert(!isa<FieldDecl>(RealDecl) && "field init shouldn't get here");
9199      Diag(RealDecl->getLocation(), diag::err_illegal_initializer);
9200      RealDecl->setInvalidDecl();
9201      return;
9202    }
9203  
9204    // C++11 [decl.spec.auto]p6. Deduce the type which 'auto' stands in for.
9205    if (TypeMayContainAuto && VDecl->getType()->isUndeducedType()) {
9206      // Attempt typo correction early so that the type of the init expression can
9207      // be deduced based on the chosen correction if the original init contains a
9208      // TypoExpr.
9209      ExprResult Res = CorrectDelayedTyposInExpr(Init, VDecl);
9210      if (!Res.isUsable()) {
9211        RealDecl->setInvalidDecl();
9212        return;
9213      }
9214      Init = Res.get();
9215  
9216      QualType DeducedType = deduceVarTypeFromInitializer(
9217          VDecl, VDecl->getDeclName(), VDecl->getType(),
9218          VDecl->getTypeSourceInfo(), VDecl->getSourceRange(), DirectInit, Init);
9219      if (DeducedType.isNull()) {
9220        RealDecl->setInvalidDecl();
9221        return;
9222      }
9223  
9224      VDecl->setType(DeducedType);
9225      assert(VDecl->isLinkageValid());
9226  
9227      // In ARC, infer lifetime.
9228      if (getLangOpts().ObjCAutoRefCount && inferObjCARCLifetime(VDecl))
9229        VDecl->setInvalidDecl();
9230  
9231      // If this is a redeclaration, check that the type we just deduced matches
9232      // the previously declared type.
9233      if (VarDecl *Old = VDecl->getPreviousDecl()) {
9234        // We never need to merge the type, because we cannot form an incomplete
9235        // array of auto, nor deduce such a type.
9236        MergeVarDeclTypes(VDecl, Old, /*MergeTypeWithPrevious*/ false);
9237      }
9238  
9239      // Check the deduced type is valid for a variable declaration.
9240      CheckVariableDeclarationType(VDecl);
9241      if (VDecl->isInvalidDecl())
9242        return;
9243    }
9244  
9245    // dllimport cannot be used on variable definitions.
9246    if (VDecl->hasAttr<DLLImportAttr>() && !VDecl->isStaticDataMember()) {
9247      Diag(VDecl->getLocation(), diag::err_attribute_dllimport_data_definition);
9248      VDecl->setInvalidDecl();
9249      return;
9250    }
9251  
9252    if (VDecl->isLocalVarDecl() && VDecl->hasExternalStorage()) {
9253      // C99 6.7.8p5. C++ has no such restriction, but that is a defect.
9254      Diag(VDecl->getLocation(), diag::err_block_extern_cant_init);
9255      VDecl->setInvalidDecl();
9256      return;
9257    }
9258  
9259    if (!VDecl->getType()->isDependentType()) {
9260      // A definition must end up with a complete type, which means it must be
9261      // complete with the restriction that an array type might be completed by
9262      // the initializer; note that later code assumes this restriction.
9263      QualType BaseDeclType = VDecl->getType();
9264      if (const ArrayType *Array = Context.getAsIncompleteArrayType(BaseDeclType))
9265        BaseDeclType = Array->getElementType();
9266      if (RequireCompleteType(VDecl->getLocation(), BaseDeclType,
9267                              diag::err_typecheck_decl_incomplete_type)) {
9268        RealDecl->setInvalidDecl();
9269        return;
9270      }
9271  
9272      // The variable can not have an abstract class type.
9273      if (RequireNonAbstractType(VDecl->getLocation(), VDecl->getType(),
9274                                 diag::err_abstract_type_in_decl,
9275                                 AbstractVariableType))
9276        VDecl->setInvalidDecl();
9277    }
9278  
9279    VarDecl *Def;
9280    if ((Def = VDecl->getDefinition()) && Def != VDecl) {
9281      NamedDecl *Hidden = nullptr;
9282      if (!hasVisibleDefinition(Def, &Hidden) &&
9283          (VDecl->getFormalLinkage() == InternalLinkage ||
9284           VDecl->getDescribedVarTemplate() ||
9285           VDecl->getNumTemplateParameterLists() ||
9286           VDecl->getDeclContext()->isDependentContext())) {
9287        // The previous definition is hidden, and multiple definitions are
9288        // permitted (in separate TUs). Form another definition of it.
9289      } else {
9290        Diag(VDecl->getLocation(), diag::err_redefinition)
9291          << VDecl->getDeclName();
9292        Diag(Def->getLocation(), diag::note_previous_definition);
9293        VDecl->setInvalidDecl();
9294        return;
9295      }
9296    }
9297  
9298    if (getLangOpts().CPlusPlus) {
9299      // C++ [class.static.data]p4
9300      //   If a static data member is of const integral or const
9301      //   enumeration type, its declaration in the class definition can
9302      //   specify a constant-initializer which shall be an integral
9303      //   constant expression (5.19). In that case, the member can appear
9304      //   in integral constant expressions. The member shall still be
9305      //   defined in a namespace scope if it is used in the program and the
9306      //   namespace scope definition shall not contain an initializer.
9307      //
9308      // We already performed a redefinition check above, but for static
9309      // data members we also need to check whether there was an in-class
9310      // declaration with an initializer.
9311      if (VDecl->isStaticDataMember() && VDecl->getCanonicalDecl()->hasInit()) {
9312        Diag(Init->getExprLoc(), diag::err_static_data_member_reinitialization)
9313            << VDecl->getDeclName();
9314        Diag(VDecl->getCanonicalDecl()->getInit()->getExprLoc(),
9315             diag::note_previous_initializer)
9316            << 0;
9317        return;
9318      }
9319  
9320      if (VDecl->hasLocalStorage())
9321        getCurFunction()->setHasBranchProtectedScope();
9322  
9323      if (DiagnoseUnexpandedParameterPack(Init, UPPC_Initializer)) {
9324        VDecl->setInvalidDecl();
9325        return;
9326      }
9327    }
9328  
9329    // OpenCL 1.1 6.5.2: "Variables allocated in the __local address space inside
9330    // a kernel function cannot be initialized."
9331    if (VDecl->getType().getAddressSpace() == LangAS::opencl_local) {
9332      Diag(VDecl->getLocation(), diag::err_local_cant_init);
9333      VDecl->setInvalidDecl();
9334      return;
9335    }
9336  
9337    // Get the decls type and save a reference for later, since
9338    // CheckInitializerTypes may change it.
9339    QualType DclT = VDecl->getType(), SavT = DclT;
9340  
9341    // Expressions default to 'id' when we're in a debugger
9342    // and we are assigning it to a variable of Objective-C pointer type.
9343    if (getLangOpts().DebuggerCastResultToId && DclT->isObjCObjectPointerType() &&
9344        Init->getType() == Context.UnknownAnyTy) {
9345      ExprResult Result = forceUnknownAnyToType(Init, Context.getObjCIdType());
9346      if (Result.isInvalid()) {
9347        VDecl->setInvalidDecl();
9348        return;
9349      }
9350      Init = Result.get();
9351    }
9352  
9353    // Perform the initialization.
9354    ParenListExpr *CXXDirectInit = dyn_cast<ParenListExpr>(Init);
9355    if (!VDecl->isInvalidDecl()) {
9356      InitializedEntity Entity = InitializedEntity::InitializeVariable(VDecl);
9357      InitializationKind Kind =
9358          DirectInit
9359              ? CXXDirectInit
9360                    ? InitializationKind::CreateDirect(VDecl->getLocation(),
9361                                                       Init->getLocStart(),
9362                                                       Init->getLocEnd())
9363                    : InitializationKind::CreateDirectList(VDecl->getLocation())
9364              : InitializationKind::CreateCopy(VDecl->getLocation(),
9365                                               Init->getLocStart());
9366  
9367      MultiExprArg Args = Init;
9368      if (CXXDirectInit)
9369        Args = MultiExprArg(CXXDirectInit->getExprs(),
9370                            CXXDirectInit->getNumExprs());
9371  
9372      // Try to correct any TypoExprs in the initialization arguments.
9373      for (size_t Idx = 0; Idx < Args.size(); ++Idx) {
9374        ExprResult Res = CorrectDelayedTyposInExpr(
9375            Args[Idx], VDecl, [this, Entity, Kind](Expr *E) {
9376              InitializationSequence Init(*this, Entity, Kind, MultiExprArg(E));
9377              return Init.Failed() ? ExprError() : E;
9378            });
9379        if (Res.isInvalid()) {
9380          VDecl->setInvalidDecl();
9381        } else if (Res.get() != Args[Idx]) {
9382          Args[Idx] = Res.get();
9383        }
9384      }
9385      if (VDecl->isInvalidDecl())
9386        return;
9387  
9388      InitializationSequence InitSeq(*this, Entity, Kind, Args);
9389      ExprResult Result = InitSeq.Perform(*this, Entity, Kind, Args, &DclT);
9390      if (Result.isInvalid()) {
9391        VDecl->setInvalidDecl();
9392        return;
9393      }
9394  
9395      Init = Result.getAs<Expr>();
9396    }
9397  
9398    // Check for self-references within variable initializers.
9399    // Variables declared within a function/method body (except for references)
9400    // are handled by a dataflow analysis.
9401    if (!VDecl->hasLocalStorage() || VDecl->getType()->isRecordType() ||
9402        VDecl->getType()->isReferenceType()) {
9403      CheckSelfReference(*this, RealDecl, Init, DirectInit);
9404    }
9405  
9406    // If the type changed, it means we had an incomplete type that was
9407    // completed by the initializer. For example:
9408    //   int ary[] = { 1, 3, 5 };
9409    // "ary" transitions from an IncompleteArrayType to a ConstantArrayType.
9410    if (!VDecl->isInvalidDecl() && (DclT != SavT))
9411      VDecl->setType(DclT);
9412  
9413    if (!VDecl->isInvalidDecl()) {
9414      checkUnsafeAssigns(VDecl->getLocation(), VDecl->getType(), Init);
9415  
9416      if (VDecl->hasAttr<BlocksAttr>())
9417        checkRetainCycles(VDecl, Init);
9418  
9419      // It is safe to assign a weak reference into a strong variable.
9420      // Although this code can still have problems:
9421      //   id x = self.weakProp;
9422      //   id y = self.weakProp;
9423      // we do not warn to warn spuriously when 'x' and 'y' are on separate
9424      // paths through the function. This should be revisited if
9425      // -Wrepeated-use-of-weak is made flow-sensitive.
9426      if (VDecl->getType().getObjCLifetime() == Qualifiers::OCL_Strong &&
9427          !Diags.isIgnored(diag::warn_arc_repeated_use_of_weak,
9428                           Init->getLocStart()))
9429        getCurFunction()->markSafeWeakUse(Init);
9430    }
9431  
9432    // The initialization is usually a full-expression.
9433    //
9434    // FIXME: If this is a braced initialization of an aggregate, it is not
9435    // an expression, and each individual field initializer is a separate
9436    // full-expression. For instance, in:
9437    //
9438    //   struct Temp { ~Temp(); };
9439    //   struct S { S(Temp); };
9440    //   struct T { S a, b; } t = { Temp(), Temp() }
9441    //
9442    // we should destroy the first Temp before constructing the second.
9443    ExprResult Result = ActOnFinishFullExpr(Init, VDecl->getLocation(),
9444                                            false,
9445                                            VDecl->isConstexpr());
9446    if (Result.isInvalid()) {
9447      VDecl->setInvalidDecl();
9448      return;
9449    }
9450    Init = Result.get();
9451  
9452    // Attach the initializer to the decl.
9453    VDecl->setInit(Init);
9454  
9455    if (VDecl->isLocalVarDecl()) {
9456      // C99 6.7.8p4: All the expressions in an initializer for an object that has
9457      // static storage duration shall be constant expressions or string literals.
9458      // C++ does not have this restriction.
9459      if (!getLangOpts().CPlusPlus && !VDecl->isInvalidDecl()) {
9460        const Expr *Culprit;
9461        if (VDecl->getStorageClass() == SC_Static)
9462          CheckForConstantInitializer(Init, DclT);
9463        // C89 is stricter than C99 for non-static aggregate types.
9464        // C89 6.5.7p3: All the expressions [...] in an initializer list
9465        // for an object that has aggregate or union type shall be
9466        // constant expressions.
9467        else if (!getLangOpts().C99 && VDecl->getType()->isAggregateType() &&
9468                 isa<InitListExpr>(Init) &&
9469                 !Init->isConstantInitializer(Context, false, &Culprit))
9470          Diag(Culprit->getExprLoc(),
9471               diag::ext_aggregate_init_not_constant)
9472            << Culprit->getSourceRange();
9473      }
9474    } else if (VDecl->isStaticDataMember() &&
9475               VDecl->getLexicalDeclContext()->isRecord()) {
9476      // This is an in-class initialization for a static data member, e.g.,
9477      //
9478      // struct S {
9479      //   static const int value = 17;
9480      // };
9481  
9482      // C++ [class.mem]p4:
9483      //   A member-declarator can contain a constant-initializer only
9484      //   if it declares a static member (9.4) of const integral or
9485      //   const enumeration type, see 9.4.2.
9486      //
9487      // C++11 [class.static.data]p3:
9488      //   If a non-volatile const static data member is of integral or
9489      //   enumeration type, its declaration in the class definition can
9490      //   specify a brace-or-equal-initializer in which every initalizer-clause
9491      //   that is an assignment-expression is a constant expression. A static
9492      //   data member of literal type can be declared in the class definition
9493      //   with the constexpr specifier; if so, its declaration shall specify a
9494      //   brace-or-equal-initializer in which every initializer-clause that is
9495      //   an assignment-expression is a constant expression.
9496  
9497      // Do nothing on dependent types.
9498      if (DclT->isDependentType()) {
9499  
9500      // Allow any 'static constexpr' members, whether or not they are of literal
9501      // type. We separately check that every constexpr variable is of literal
9502      // type.
9503      } else if (VDecl->isConstexpr()) {
9504  
9505      // Require constness.
9506      } else if (!DclT.isConstQualified()) {
9507        Diag(VDecl->getLocation(), diag::err_in_class_initializer_non_const)
9508          << Init->getSourceRange();
9509        VDecl->setInvalidDecl();
9510  
9511      // We allow integer constant expressions in all cases.
9512      } else if (DclT->isIntegralOrEnumerationType()) {
9513        // Check whether the expression is a constant expression.
9514        SourceLocation Loc;
9515        if (getLangOpts().CPlusPlus11 && DclT.isVolatileQualified())
9516          // In C++11, a non-constexpr const static data member with an
9517          // in-class initializer cannot be volatile.
9518          Diag(VDecl->getLocation(), diag::err_in_class_initializer_volatile);
9519        else if (Init->isValueDependent())
9520          ; // Nothing to check.
9521        else if (Init->isIntegerConstantExpr(Context, &Loc))
9522          ; // Ok, it's an ICE!
9523        else if (Init->isEvaluatable(Context)) {
9524          // If we can constant fold the initializer through heroics, accept it,
9525          // but report this as a use of an extension for -pedantic.
9526          Diag(Loc, diag::ext_in_class_initializer_non_constant)
9527            << Init->getSourceRange();
9528        } else {
9529          // Otherwise, this is some crazy unknown case.  Report the issue at the
9530          // location provided by the isIntegerConstantExpr failed check.
9531          Diag(Loc, diag::err_in_class_initializer_non_constant)
9532            << Init->getSourceRange();
9533          VDecl->setInvalidDecl();
9534        }
9535  
9536      // We allow foldable floating-point constants as an extension.
9537      } else if (DclT->isFloatingType()) { // also permits complex, which is ok
9538        // In C++98, this is a GNU extension. In C++11, it is not, but we support
9539        // it anyway and provide a fixit to add the 'constexpr'.
9540        if (getLangOpts().CPlusPlus11) {
9541          Diag(VDecl->getLocation(),
9542               diag::ext_in_class_initializer_float_type_cxx11)
9543              << DclT << Init->getSourceRange();
9544          Diag(VDecl->getLocStart(),
9545               diag::note_in_class_initializer_float_type_cxx11)
9546              << FixItHint::CreateInsertion(VDecl->getLocStart(), "constexpr ");
9547        } else {
9548          Diag(VDecl->getLocation(), diag::ext_in_class_initializer_float_type)
9549            << DclT << Init->getSourceRange();
9550  
9551          if (!Init->isValueDependent() && !Init->isEvaluatable(Context)) {
9552            Diag(Init->getExprLoc(), diag::err_in_class_initializer_non_constant)
9553              << Init->getSourceRange();
9554            VDecl->setInvalidDecl();
9555          }
9556        }
9557  
9558      // Suggest adding 'constexpr' in C++11 for literal types.
9559      } else if (getLangOpts().CPlusPlus11 && DclT->isLiteralType(Context)) {
9560        Diag(VDecl->getLocation(), diag::err_in_class_initializer_literal_type)
9561          << DclT << Init->getSourceRange()
9562          << FixItHint::CreateInsertion(VDecl->getLocStart(), "constexpr ");
9563        VDecl->setConstexpr(true);
9564  
9565      } else {
9566        Diag(VDecl->getLocation(), diag::err_in_class_initializer_bad_type)
9567          << DclT << Init->getSourceRange();
9568        VDecl->setInvalidDecl();
9569      }
9570    } else if (VDecl->isFileVarDecl()) {
9571      if (VDecl->getStorageClass() == SC_Extern &&
9572          (!getLangOpts().CPlusPlus ||
9573           !(Context.getBaseElementType(VDecl->getType()).isConstQualified() ||
9574             VDecl->isExternC())) &&
9575          !isTemplateInstantiation(VDecl->getTemplateSpecializationKind()))
9576        Diag(VDecl->getLocation(), diag::warn_extern_init);
9577  
9578      // C99 6.7.8p4. All file scoped initializers need to be constant.
9579      if (!getLangOpts().CPlusPlus && !VDecl->isInvalidDecl())
9580        CheckForConstantInitializer(Init, DclT);
9581    }
9582  
9583    // We will represent direct-initialization similarly to copy-initialization:
9584    //    int x(1);  -as-> int x = 1;
9585    //    ClassType x(a,b,c); -as-> ClassType x = ClassType(a,b,c);
9586    //
9587    // Clients that want to distinguish between the two forms, can check for
9588    // direct initializer using VarDecl::getInitStyle().
9589    // A major benefit is that clients that don't particularly care about which
9590    // exactly form was it (like the CodeGen) can handle both cases without
9591    // special case code.
9592  
9593    // C++ 8.5p11:
9594    // The form of initialization (using parentheses or '=') is generally
9595    // insignificant, but does matter when the entity being initialized has a
9596    // class type.
9597    if (CXXDirectInit) {
9598      assert(DirectInit && "Call-style initializer must be direct init.");
9599      VDecl->setInitStyle(VarDecl::CallInit);
9600    } else if (DirectInit) {
9601      // This must be list-initialization. No other way is direct-initialization.
9602      VDecl->setInitStyle(VarDecl::ListInit);
9603    }
9604  
9605    CheckCompleteVariableDeclaration(VDecl);
9606  }
9607  
9608  /// ActOnInitializerError - Given that there was an error parsing an
9609  /// initializer for the given declaration, try to return to some form
9610  /// of sanity.
ActOnInitializerError(Decl * D)9611  void Sema::ActOnInitializerError(Decl *D) {
9612    // Our main concern here is re-establishing invariants like "a
9613    // variable's type is either dependent or complete".
9614    if (!D || D->isInvalidDecl()) return;
9615  
9616    VarDecl *VD = dyn_cast<VarDecl>(D);
9617    if (!VD) return;
9618  
9619    // Auto types are meaningless if we can't make sense of the initializer.
9620    if (ParsingInitForAutoVars.count(D)) {
9621      D->setInvalidDecl();
9622      return;
9623    }
9624  
9625    QualType Ty = VD->getType();
9626    if (Ty->isDependentType()) return;
9627  
9628    // Require a complete type.
9629    if (RequireCompleteType(VD->getLocation(),
9630                            Context.getBaseElementType(Ty),
9631                            diag::err_typecheck_decl_incomplete_type)) {
9632      VD->setInvalidDecl();
9633      return;
9634    }
9635  
9636    // Require a non-abstract type.
9637    if (RequireNonAbstractType(VD->getLocation(), Ty,
9638                               diag::err_abstract_type_in_decl,
9639                               AbstractVariableType)) {
9640      VD->setInvalidDecl();
9641      return;
9642    }
9643  
9644    // Don't bother complaining about constructors or destructors,
9645    // though.
9646  }
9647  
ActOnUninitializedDecl(Decl * RealDecl,bool TypeMayContainAuto)9648  void Sema::ActOnUninitializedDecl(Decl *RealDecl,
9649                                    bool TypeMayContainAuto) {
9650    // If there is no declaration, there was an error parsing it. Just ignore it.
9651    if (!RealDecl)
9652      return;
9653  
9654    if (VarDecl *Var = dyn_cast<VarDecl>(RealDecl)) {
9655      QualType Type = Var->getType();
9656  
9657      // C++11 [dcl.spec.auto]p3
9658      if (TypeMayContainAuto && Type->getContainedAutoType()) {
9659        Diag(Var->getLocation(), diag::err_auto_var_requires_init)
9660          << Var->getDeclName() << Type;
9661        Var->setInvalidDecl();
9662        return;
9663      }
9664  
9665      // C++11 [class.static.data]p3: A static data member can be declared with
9666      // the constexpr specifier; if so, its declaration shall specify
9667      // a brace-or-equal-initializer.
9668      // C++11 [dcl.constexpr]p1: The constexpr specifier shall be applied only to
9669      // the definition of a variable [...] or the declaration of a static data
9670      // member.
9671      if (Var->isConstexpr() && !Var->isThisDeclarationADefinition()) {
9672        if (Var->isStaticDataMember())
9673          Diag(Var->getLocation(),
9674               diag::err_constexpr_static_mem_var_requires_init)
9675            << Var->getDeclName();
9676        else
9677          Diag(Var->getLocation(), diag::err_invalid_constexpr_var_decl);
9678        Var->setInvalidDecl();
9679        return;
9680      }
9681  
9682      // C++ Concepts TS [dcl.spec.concept]p1: [...]  A variable template
9683      // definition having the concept specifier is called a variable concept. A
9684      // concept definition refers to [...] a variable concept and its initializer.
9685      if (Var->isConcept()) {
9686        Diag(Var->getLocation(), diag::err_var_concept_not_initialized);
9687        Var->setInvalidDecl();
9688        return;
9689      }
9690  
9691      // OpenCL v1.1 s6.5.3: variables declared in the constant address space must
9692      // be initialized.
9693      if (!Var->isInvalidDecl() &&
9694          Var->getType().getAddressSpace() == LangAS::opencl_constant &&
9695          Var->getStorageClass() != SC_Extern && !Var->getInit()) {
9696        Diag(Var->getLocation(), diag::err_opencl_constant_no_init);
9697        Var->setInvalidDecl();
9698        return;
9699      }
9700  
9701      switch (Var->isThisDeclarationADefinition()) {
9702      case VarDecl::Definition:
9703        if (!Var->isStaticDataMember() || !Var->getAnyInitializer())
9704          break;
9705  
9706        // We have an out-of-line definition of a static data member
9707        // that has an in-class initializer, so we type-check this like
9708        // a declaration.
9709        //
9710        // Fall through
9711  
9712      case VarDecl::DeclarationOnly:
9713        // It's only a declaration.
9714  
9715        // Block scope. C99 6.7p7: If an identifier for an object is
9716        // declared with no linkage (C99 6.2.2p6), the type for the
9717        // object shall be complete.
9718        if (!Type->isDependentType() && Var->isLocalVarDecl() &&
9719            !Var->hasLinkage() && !Var->isInvalidDecl() &&
9720            RequireCompleteType(Var->getLocation(), Type,
9721                                diag::err_typecheck_decl_incomplete_type))
9722          Var->setInvalidDecl();
9723  
9724        // Make sure that the type is not abstract.
9725        if (!Type->isDependentType() && !Var->isInvalidDecl() &&
9726            RequireNonAbstractType(Var->getLocation(), Type,
9727                                   diag::err_abstract_type_in_decl,
9728                                   AbstractVariableType))
9729          Var->setInvalidDecl();
9730        if (!Type->isDependentType() && !Var->isInvalidDecl() &&
9731            Var->getStorageClass() == SC_PrivateExtern) {
9732          Diag(Var->getLocation(), diag::warn_private_extern);
9733          Diag(Var->getLocation(), diag::note_private_extern);
9734        }
9735  
9736        return;
9737  
9738      case VarDecl::TentativeDefinition:
9739        // File scope. C99 6.9.2p2: A declaration of an identifier for an
9740        // object that has file scope without an initializer, and without a
9741        // storage-class specifier or with the storage-class specifier "static",
9742        // constitutes a tentative definition. Note: A tentative definition with
9743        // external linkage is valid (C99 6.2.2p5).
9744        if (!Var->isInvalidDecl()) {
9745          if (const IncompleteArrayType *ArrayT
9746                                      = Context.getAsIncompleteArrayType(Type)) {
9747            if (RequireCompleteType(Var->getLocation(),
9748                                    ArrayT->getElementType(),
9749                                    diag::err_illegal_decl_array_incomplete_type))
9750              Var->setInvalidDecl();
9751          } else if (Var->getStorageClass() == SC_Static) {
9752            // C99 6.9.2p3: If the declaration of an identifier for an object is
9753            // a tentative definition and has internal linkage (C99 6.2.2p3), the
9754            // declared type shall not be an incomplete type.
9755            // NOTE: code such as the following
9756            //     static struct s;
9757            //     struct s { int a; };
9758            // is accepted by gcc. Hence here we issue a warning instead of
9759            // an error and we do not invalidate the static declaration.
9760            // NOTE: to avoid multiple warnings, only check the first declaration.
9761            if (Var->isFirstDecl())
9762              RequireCompleteType(Var->getLocation(), Type,
9763                                  diag::ext_typecheck_decl_incomplete_type);
9764          }
9765        }
9766  
9767        // Record the tentative definition; we're done.
9768        if (!Var->isInvalidDecl())
9769          TentativeDefinitions.push_back(Var);
9770        return;
9771      }
9772  
9773      // Provide a specific diagnostic for uninitialized variable
9774      // definitions with incomplete array type.
9775      if (Type->isIncompleteArrayType()) {
9776        Diag(Var->getLocation(),
9777             diag::err_typecheck_incomplete_array_needs_initializer);
9778        Var->setInvalidDecl();
9779        return;
9780      }
9781  
9782      // Provide a specific diagnostic for uninitialized variable
9783      // definitions with reference type.
9784      if (Type->isReferenceType()) {
9785        Diag(Var->getLocation(), diag::err_reference_var_requires_init)
9786          << Var->getDeclName()
9787          << SourceRange(Var->getLocation(), Var->getLocation());
9788        Var->setInvalidDecl();
9789        return;
9790      }
9791  
9792      // Do not attempt to type-check the default initializer for a
9793      // variable with dependent type.
9794      if (Type->isDependentType())
9795        return;
9796  
9797      if (Var->isInvalidDecl())
9798        return;
9799  
9800      if (!Var->hasAttr<AliasAttr>()) {
9801        if (RequireCompleteType(Var->getLocation(),
9802                                Context.getBaseElementType(Type),
9803                                diag::err_typecheck_decl_incomplete_type)) {
9804          Var->setInvalidDecl();
9805          return;
9806        }
9807      } else {
9808        return;
9809      }
9810  
9811      // The variable can not have an abstract class type.
9812      if (RequireNonAbstractType(Var->getLocation(), Type,
9813                                 diag::err_abstract_type_in_decl,
9814                                 AbstractVariableType)) {
9815        Var->setInvalidDecl();
9816        return;
9817      }
9818  
9819      // Check for jumps past the implicit initializer.  C++0x
9820      // clarifies that this applies to a "variable with automatic
9821      // storage duration", not a "local variable".
9822      // C++11 [stmt.dcl]p3
9823      //   A program that jumps from a point where a variable with automatic
9824      //   storage duration is not in scope to a point where it is in scope is
9825      //   ill-formed unless the variable has scalar type, class type with a
9826      //   trivial default constructor and a trivial destructor, a cv-qualified
9827      //   version of one of these types, or an array of one of the preceding
9828      //   types and is declared without an initializer.
9829      if (getLangOpts().CPlusPlus && Var->hasLocalStorage()) {
9830        if (const RecordType *Record
9831              = Context.getBaseElementType(Type)->getAs<RecordType>()) {
9832          CXXRecordDecl *CXXRecord = cast<CXXRecordDecl>(Record->getDecl());
9833          // Mark the function for further checking even if the looser rules of
9834          // C++11 do not require such checks, so that we can diagnose
9835          // incompatibilities with C++98.
9836          if (!CXXRecord->isPOD())
9837            getCurFunction()->setHasBranchProtectedScope();
9838        }
9839      }
9840  
9841      // C++03 [dcl.init]p9:
9842      //   If no initializer is specified for an object, and the
9843      //   object is of (possibly cv-qualified) non-POD class type (or
9844      //   array thereof), the object shall be default-initialized; if
9845      //   the object is of const-qualified type, the underlying class
9846      //   type shall have a user-declared default
9847      //   constructor. Otherwise, if no initializer is specified for
9848      //   a non- static object, the object and its subobjects, if
9849      //   any, have an indeterminate initial value); if the object
9850      //   or any of its subobjects are of const-qualified type, the
9851      //   program is ill-formed.
9852      // C++0x [dcl.init]p11:
9853      //   If no initializer is specified for an object, the object is
9854      //   default-initialized; [...].
9855      InitializedEntity Entity = InitializedEntity::InitializeVariable(Var);
9856      InitializationKind Kind
9857        = InitializationKind::CreateDefault(Var->getLocation());
9858  
9859      InitializationSequence InitSeq(*this, Entity, Kind, None);
9860      ExprResult Init = InitSeq.Perform(*this, Entity, Kind, None);
9861      if (Init.isInvalid())
9862        Var->setInvalidDecl();
9863      else if (Init.get()) {
9864        Var->setInit(MaybeCreateExprWithCleanups(Init.get()));
9865        // This is important for template substitution.
9866        Var->setInitStyle(VarDecl::CallInit);
9867      }
9868  
9869      CheckCompleteVariableDeclaration(Var);
9870    }
9871  }
9872  
ActOnCXXForRangeDecl(Decl * D)9873  void Sema::ActOnCXXForRangeDecl(Decl *D) {
9874    VarDecl *VD = dyn_cast<VarDecl>(D);
9875    if (!VD) {
9876      Diag(D->getLocation(), diag::err_for_range_decl_must_be_var);
9877      D->setInvalidDecl();
9878      return;
9879    }
9880  
9881    VD->setCXXForRangeDecl(true);
9882  
9883    // for-range-declaration cannot be given a storage class specifier.
9884    int Error = -1;
9885    switch (VD->getStorageClass()) {
9886    case SC_None:
9887      break;
9888    case SC_Extern:
9889      Error = 0;
9890      break;
9891    case SC_Static:
9892      Error = 1;
9893      break;
9894    case SC_PrivateExtern:
9895      Error = 2;
9896      break;
9897    case SC_Auto:
9898      Error = 3;
9899      break;
9900    case SC_Register:
9901      Error = 4;
9902      break;
9903    }
9904    if (Error != -1) {
9905      Diag(VD->getOuterLocStart(), diag::err_for_range_storage_class)
9906        << VD->getDeclName() << Error;
9907      D->setInvalidDecl();
9908    }
9909  }
9910  
9911  StmtResult
ActOnCXXForRangeIdentifier(Scope * S,SourceLocation IdentLoc,IdentifierInfo * Ident,ParsedAttributes & Attrs,SourceLocation AttrEnd)9912  Sema::ActOnCXXForRangeIdentifier(Scope *S, SourceLocation IdentLoc,
9913                                   IdentifierInfo *Ident,
9914                                   ParsedAttributes &Attrs,
9915                                   SourceLocation AttrEnd) {
9916    // C++1y [stmt.iter]p1:
9917    //   A range-based for statement of the form
9918    //      for ( for-range-identifier : for-range-initializer ) statement
9919    //   is equivalent to
9920    //      for ( auto&& for-range-identifier : for-range-initializer ) statement
9921    DeclSpec DS(Attrs.getPool().getFactory());
9922  
9923    const char *PrevSpec;
9924    unsigned DiagID;
9925    DS.SetTypeSpecType(DeclSpec::TST_auto, IdentLoc, PrevSpec, DiagID,
9926                       getPrintingPolicy());
9927  
9928    Declarator D(DS, Declarator::ForContext);
9929    D.SetIdentifier(Ident, IdentLoc);
9930    D.takeAttributes(Attrs, AttrEnd);
9931  
9932    ParsedAttributes EmptyAttrs(Attrs.getPool().getFactory());
9933    D.AddTypeInfo(DeclaratorChunk::getReference(0, IdentLoc, /*lvalue*/false),
9934                  EmptyAttrs, IdentLoc);
9935    Decl *Var = ActOnDeclarator(S, D);
9936    cast<VarDecl>(Var)->setCXXForRangeDecl(true);
9937    FinalizeDeclaration(Var);
9938    return ActOnDeclStmt(FinalizeDeclaratorGroup(S, DS, Var), IdentLoc,
9939                         AttrEnd.isValid() ? AttrEnd : IdentLoc);
9940  }
9941  
CheckCompleteVariableDeclaration(VarDecl * var)9942  void Sema::CheckCompleteVariableDeclaration(VarDecl *var) {
9943    if (var->isInvalidDecl()) return;
9944  
9945    // In Objective-C, don't allow jumps past the implicit initialization of a
9946    // local retaining variable.
9947    if (getLangOpts().ObjC1 &&
9948        var->hasLocalStorage()) {
9949      switch (var->getType().getObjCLifetime()) {
9950      case Qualifiers::OCL_None:
9951      case Qualifiers::OCL_ExplicitNone:
9952      case Qualifiers::OCL_Autoreleasing:
9953        break;
9954  
9955      case Qualifiers::OCL_Weak:
9956      case Qualifiers::OCL_Strong:
9957        getCurFunction()->setHasBranchProtectedScope();
9958        break;
9959      }
9960    }
9961  
9962    // Warn about externally-visible variables being defined without a
9963    // prior declaration.  We only want to do this for global
9964    // declarations, but we also specifically need to avoid doing it for
9965    // class members because the linkage of an anonymous class can
9966    // change if it's later given a typedef name.
9967    if (var->isThisDeclarationADefinition() &&
9968        var->getDeclContext()->getRedeclContext()->isFileContext() &&
9969        var->isExternallyVisible() && var->hasLinkage() &&
9970        !getDiagnostics().isIgnored(diag::warn_missing_variable_declarations,
9971                                    var->getLocation())) {
9972      // Find a previous declaration that's not a definition.
9973      VarDecl *prev = var->getPreviousDecl();
9974      while (prev && prev->isThisDeclarationADefinition())
9975        prev = prev->getPreviousDecl();
9976  
9977      if (!prev)
9978        Diag(var->getLocation(), diag::warn_missing_variable_declarations) << var;
9979    }
9980  
9981    if (var->getTLSKind() == VarDecl::TLS_Static) {
9982      const Expr *Culprit;
9983      if (var->getType().isDestructedType()) {
9984        // GNU C++98 edits for __thread, [basic.start.term]p3:
9985        //   The type of an object with thread storage duration shall not
9986        //   have a non-trivial destructor.
9987        Diag(var->getLocation(), diag::err_thread_nontrivial_dtor);
9988        if (getLangOpts().CPlusPlus11)
9989          Diag(var->getLocation(), diag::note_use_thread_local);
9990      } else if (getLangOpts().CPlusPlus && var->hasInit() &&
9991                 !var->getInit()->isConstantInitializer(
9992                     Context, var->getType()->isReferenceType(), &Culprit)) {
9993        // GNU C++98 edits for __thread, [basic.start.init]p4:
9994        //   An object of thread storage duration shall not require dynamic
9995        //   initialization.
9996        // FIXME: Need strict checking here.
9997        Diag(Culprit->getExprLoc(), diag::err_thread_dynamic_init)
9998          << Culprit->getSourceRange();
9999        if (getLangOpts().CPlusPlus11)
10000          Diag(var->getLocation(), diag::note_use_thread_local);
10001      }
10002  
10003    }
10004  
10005    // Apply section attributes and pragmas to global variables.
10006    bool GlobalStorage = var->hasGlobalStorage();
10007    if (GlobalStorage && var->isThisDeclarationADefinition() &&
10008        ActiveTemplateInstantiations.empty()) {
10009      PragmaStack<StringLiteral *> *Stack = nullptr;
10010      int SectionFlags = ASTContext::PSF_Implicit | ASTContext::PSF_Read;
10011      if (var->getType().isConstQualified())
10012        Stack = &ConstSegStack;
10013      else if (!var->getInit()) {
10014        Stack = &BSSSegStack;
10015        SectionFlags |= ASTContext::PSF_Write;
10016      } else {
10017        Stack = &DataSegStack;
10018        SectionFlags |= ASTContext::PSF_Write;
10019      }
10020      if (Stack->CurrentValue && !var->hasAttr<SectionAttr>()) {
10021        var->addAttr(SectionAttr::CreateImplicit(
10022            Context, SectionAttr::Declspec_allocate,
10023            Stack->CurrentValue->getString(), Stack->CurrentPragmaLocation));
10024      }
10025      if (const SectionAttr *SA = var->getAttr<SectionAttr>())
10026        if (UnifySection(SA->getName(), SectionFlags, var))
10027          var->dropAttr<SectionAttr>();
10028  
10029      // Apply the init_seg attribute if this has an initializer.  If the
10030      // initializer turns out to not be dynamic, we'll end up ignoring this
10031      // attribute.
10032      if (CurInitSeg && var->getInit())
10033        var->addAttr(InitSegAttr::CreateImplicit(Context, CurInitSeg->getString(),
10034                                                 CurInitSegLoc));
10035    }
10036  
10037    // All the following checks are C++ only.
10038    if (!getLangOpts().CPlusPlus) return;
10039  
10040    QualType type = var->getType();
10041    if (type->isDependentType()) return;
10042  
10043    // __block variables might require us to capture a copy-initializer.
10044    if (var->hasAttr<BlocksAttr>()) {
10045      // It's currently invalid to ever have a __block variable with an
10046      // array type; should we diagnose that here?
10047  
10048      // Regardless, we don't want to ignore array nesting when
10049      // constructing this copy.
10050      if (type->isStructureOrClassType()) {
10051        EnterExpressionEvaluationContext scope(*this, PotentiallyEvaluated);
10052        SourceLocation poi = var->getLocation();
10053        Expr *varRef =new (Context) DeclRefExpr(var, false, type, VK_LValue, poi);
10054        ExprResult result
10055          = PerformMoveOrCopyInitialization(
10056              InitializedEntity::InitializeBlock(poi, type, false),
10057              var, var->getType(), varRef, /*AllowNRVO=*/true);
10058        if (!result.isInvalid()) {
10059          result = MaybeCreateExprWithCleanups(result);
10060          Expr *init = result.getAs<Expr>();
10061          Context.setBlockVarCopyInits(var, init);
10062        }
10063      }
10064    }
10065  
10066    Expr *Init = var->getInit();
10067    bool IsGlobal = GlobalStorage && !var->isStaticLocal();
10068    QualType baseType = Context.getBaseElementType(type);
10069  
10070    if (!var->getDeclContext()->isDependentContext() &&
10071        Init && !Init->isValueDependent()) {
10072      if (IsGlobal && !var->isConstexpr() &&
10073          !getDiagnostics().isIgnored(diag::warn_global_constructor,
10074                                      var->getLocation())) {
10075        // Warn about globals which don't have a constant initializer.  Don't
10076        // warn about globals with a non-trivial destructor because we already
10077        // warned about them.
10078        CXXRecordDecl *RD = baseType->getAsCXXRecordDecl();
10079        if (!(RD && !RD->hasTrivialDestructor()) &&
10080            !Init->isConstantInitializer(Context, baseType->isReferenceType()))
10081          Diag(var->getLocation(), diag::warn_global_constructor)
10082            << Init->getSourceRange();
10083      }
10084  
10085      if (var->isConstexpr()) {
10086        SmallVector<PartialDiagnosticAt, 8> Notes;
10087        if (!var->evaluateValue(Notes) || !var->isInitICE()) {
10088          SourceLocation DiagLoc = var->getLocation();
10089          // If the note doesn't add any useful information other than a source
10090          // location, fold it into the primary diagnostic.
10091          if (Notes.size() == 1 && Notes[0].second.getDiagID() ==
10092                diag::note_invalid_subexpr_in_const_expr) {
10093            DiagLoc = Notes[0].first;
10094            Notes.clear();
10095          }
10096          Diag(DiagLoc, diag::err_constexpr_var_requires_const_init)
10097            << var << Init->getSourceRange();
10098          for (unsigned I = 0, N = Notes.size(); I != N; ++I)
10099            Diag(Notes[I].first, Notes[I].second);
10100        }
10101      } else if (var->isUsableInConstantExpressions(Context)) {
10102        // Check whether the initializer of a const variable of integral or
10103        // enumeration type is an ICE now, since we can't tell whether it was
10104        // initialized by a constant expression if we check later.
10105        var->checkInitIsICE();
10106      }
10107    }
10108  
10109    // Require the destructor.
10110    if (const RecordType *recordType = baseType->getAs<RecordType>())
10111      FinalizeVarWithDestructor(var, recordType);
10112  }
10113  
10114  /// \brief Determines if a variable's alignment is dependent.
hasDependentAlignment(VarDecl * VD)10115  static bool hasDependentAlignment(VarDecl *VD) {
10116    if (VD->getType()->isDependentType())
10117      return true;
10118    for (auto *I : VD->specific_attrs<AlignedAttr>())
10119      if (I->isAlignmentDependent())
10120        return true;
10121    return false;
10122  }
10123  
10124  /// FinalizeDeclaration - called by ParseDeclarationAfterDeclarator to perform
10125  /// any semantic actions necessary after any initializer has been attached.
10126  void
FinalizeDeclaration(Decl * ThisDecl)10127  Sema::FinalizeDeclaration(Decl *ThisDecl) {
10128    // Note that we are no longer parsing the initializer for this declaration.
10129    ParsingInitForAutoVars.erase(ThisDecl);
10130  
10131    VarDecl *VD = dyn_cast_or_null<VarDecl>(ThisDecl);
10132    if (!VD)
10133      return;
10134  
10135    checkAttributesAfterMerging(*this, *VD);
10136  
10137    // Perform TLS alignment check here after attributes attached to the variable
10138    // which may affect the alignment have been processed. Only perform the check
10139    // if the target has a maximum TLS alignment (zero means no constraints).
10140    if (unsigned MaxAlign = Context.getTargetInfo().getMaxTLSAlign()) {
10141      // Protect the check so that it's not performed on dependent types and
10142      // dependent alignments (we can't determine the alignment in that case).
10143      if (VD->getTLSKind() && !hasDependentAlignment(VD)) {
10144        CharUnits MaxAlignChars = Context.toCharUnitsFromBits(MaxAlign);
10145        if (Context.getDeclAlign(VD) > MaxAlignChars) {
10146          Diag(VD->getLocation(), diag::err_tls_var_aligned_over_maximum)
10147            << (unsigned)Context.getDeclAlign(VD).getQuantity() << VD
10148            << (unsigned)MaxAlignChars.getQuantity();
10149        }
10150      }
10151    }
10152  
10153    // Static locals inherit dll attributes from their function.
10154    if (VD->isStaticLocal()) {
10155      if (FunctionDecl *FD =
10156              dyn_cast_or_null<FunctionDecl>(VD->getParentFunctionOrMethod())) {
10157        if (Attr *A = getDLLAttr(FD)) {
10158          auto *NewAttr = cast<InheritableAttr>(A->clone(getASTContext()));
10159          NewAttr->setInherited(true);
10160          VD->addAttr(NewAttr);
10161        }
10162      }
10163    }
10164  
10165    // Grab the dllimport or dllexport attribute off of the VarDecl.
10166    const InheritableAttr *DLLAttr = getDLLAttr(VD);
10167  
10168    // Imported static data members cannot be defined out-of-line.
10169    if (const auto *IA = dyn_cast_or_null<DLLImportAttr>(DLLAttr)) {
10170      if (VD->isStaticDataMember() && VD->isOutOfLine() &&
10171          VD->isThisDeclarationADefinition()) {
10172        // We allow definitions of dllimport class template static data members
10173        // with a warning.
10174        CXXRecordDecl *Context =
10175          cast<CXXRecordDecl>(VD->getFirstDecl()->getDeclContext());
10176        bool IsClassTemplateMember =
10177            isa<ClassTemplatePartialSpecializationDecl>(Context) ||
10178            Context->getDescribedClassTemplate();
10179  
10180        Diag(VD->getLocation(),
10181             IsClassTemplateMember
10182                 ? diag::warn_attribute_dllimport_static_field_definition
10183                 : diag::err_attribute_dllimport_static_field_definition);
10184        Diag(IA->getLocation(), diag::note_attribute);
10185        if (!IsClassTemplateMember)
10186          VD->setInvalidDecl();
10187      }
10188    }
10189  
10190    // dllimport/dllexport variables cannot be thread local, their TLS index
10191    // isn't exported with the variable.
10192    if (DLLAttr && VD->getTLSKind()) {
10193      auto *F = dyn_cast_or_null<FunctionDecl>(VD->getParentFunctionOrMethod());
10194      if (F && getDLLAttr(F)) {
10195        assert(VD->isStaticLocal());
10196        // But if this is a static local in a dlimport/dllexport function, the
10197        // function will never be inlined, which means the var would never be
10198        // imported, so having it marked import/export is safe.
10199      } else {
10200        Diag(VD->getLocation(), diag::err_attribute_dll_thread_local) << VD
10201                                                                      << DLLAttr;
10202        VD->setInvalidDecl();
10203      }
10204    }
10205  
10206    if (UsedAttr *Attr = VD->getAttr<UsedAttr>()) {
10207      if (!Attr->isInherited() && !VD->isThisDeclarationADefinition()) {
10208        Diag(Attr->getLocation(), diag::warn_attribute_ignored) << Attr;
10209        VD->dropAttr<UsedAttr>();
10210      }
10211    }
10212  
10213    const DeclContext *DC = VD->getDeclContext();
10214    // If there's a #pragma GCC visibility in scope, and this isn't a class
10215    // member, set the visibility of this variable.
10216    if (DC->getRedeclContext()->isFileContext() && VD->isExternallyVisible())
10217      AddPushedVisibilityAttribute(VD);
10218  
10219    // FIXME: Warn on unused templates.
10220    if (VD->isFileVarDecl() && !VD->getDescribedVarTemplate() &&
10221        !isa<VarTemplatePartialSpecializationDecl>(VD))
10222      MarkUnusedFileScopedDecl(VD);
10223  
10224    // Now we have parsed the initializer and can update the table of magic
10225    // tag values.
10226    if (!VD->hasAttr<TypeTagForDatatypeAttr>() ||
10227        !VD->getType()->isIntegralOrEnumerationType())
10228      return;
10229  
10230    for (const auto *I : ThisDecl->specific_attrs<TypeTagForDatatypeAttr>()) {
10231      const Expr *MagicValueExpr = VD->getInit();
10232      if (!MagicValueExpr) {
10233        continue;
10234      }
10235      llvm::APSInt MagicValueInt;
10236      if (!MagicValueExpr->isIntegerConstantExpr(MagicValueInt, Context)) {
10237        Diag(I->getRange().getBegin(),
10238             diag::err_type_tag_for_datatype_not_ice)
10239          << LangOpts.CPlusPlus << MagicValueExpr->getSourceRange();
10240        continue;
10241      }
10242      if (MagicValueInt.getActiveBits() > 64) {
10243        Diag(I->getRange().getBegin(),
10244             diag::err_type_tag_for_datatype_too_large)
10245          << LangOpts.CPlusPlus << MagicValueExpr->getSourceRange();
10246        continue;
10247      }
10248      uint64_t MagicValue = MagicValueInt.getZExtValue();
10249      RegisterTypeTagForDatatype(I->getArgumentKind(),
10250                                 MagicValue,
10251                                 I->getMatchingCType(),
10252                                 I->getLayoutCompatible(),
10253                                 I->getMustBeNull());
10254    }
10255  }
10256  
FinalizeDeclaratorGroup(Scope * S,const DeclSpec & DS,ArrayRef<Decl * > Group)10257  Sema::DeclGroupPtrTy Sema::FinalizeDeclaratorGroup(Scope *S, const DeclSpec &DS,
10258                                                     ArrayRef<Decl *> Group) {
10259    SmallVector<Decl*, 8> Decls;
10260  
10261    if (DS.isTypeSpecOwned())
10262      Decls.push_back(DS.getRepAsDecl());
10263  
10264    DeclaratorDecl *FirstDeclaratorInGroup = nullptr;
10265    for (unsigned i = 0, e = Group.size(); i != e; ++i)
10266      if (Decl *D = Group[i]) {
10267        if (DeclaratorDecl *DD = dyn_cast<DeclaratorDecl>(D))
10268          if (!FirstDeclaratorInGroup)
10269            FirstDeclaratorInGroup = DD;
10270        Decls.push_back(D);
10271      }
10272  
10273    if (DeclSpec::isDeclRep(DS.getTypeSpecType())) {
10274      if (TagDecl *Tag = dyn_cast_or_null<TagDecl>(DS.getRepAsDecl())) {
10275        handleTagNumbering(Tag, S);
10276        if (FirstDeclaratorInGroup && !Tag->hasNameForLinkage() &&
10277            getLangOpts().CPlusPlus)
10278          Context.addDeclaratorForUnnamedTagDecl(Tag, FirstDeclaratorInGroup);
10279      }
10280    }
10281  
10282    return BuildDeclaratorGroup(Decls, DS.containsPlaceholderType());
10283  }
10284  
10285  /// BuildDeclaratorGroup - convert a list of declarations into a declaration
10286  /// group, performing any necessary semantic checking.
10287  Sema::DeclGroupPtrTy
BuildDeclaratorGroup(MutableArrayRef<Decl * > Group,bool TypeMayContainAuto)10288  Sema::BuildDeclaratorGroup(MutableArrayRef<Decl *> Group,
10289                             bool TypeMayContainAuto) {
10290    // C++0x [dcl.spec.auto]p7:
10291    //   If the type deduced for the template parameter U is not the same in each
10292    //   deduction, the program is ill-formed.
10293    // FIXME: When initializer-list support is added, a distinction is needed
10294    // between the deduced type U and the deduced type which 'auto' stands for.
10295    //   auto a = 0, b = { 1, 2, 3 };
10296    // is legal because the deduced type U is 'int' in both cases.
10297    if (TypeMayContainAuto && Group.size() > 1) {
10298      QualType Deduced;
10299      CanQualType DeducedCanon;
10300      VarDecl *DeducedDecl = nullptr;
10301      for (unsigned i = 0, e = Group.size(); i != e; ++i) {
10302        if (VarDecl *D = dyn_cast<VarDecl>(Group[i])) {
10303          AutoType *AT = D->getType()->getContainedAutoType();
10304          // Don't reissue diagnostics when instantiating a template.
10305          if (AT && D->isInvalidDecl())
10306            break;
10307          QualType U = AT ? AT->getDeducedType() : QualType();
10308          if (!U.isNull()) {
10309            CanQualType UCanon = Context.getCanonicalType(U);
10310            if (Deduced.isNull()) {
10311              Deduced = U;
10312              DeducedCanon = UCanon;
10313              DeducedDecl = D;
10314            } else if (DeducedCanon != UCanon) {
10315              Diag(D->getTypeSourceInfo()->getTypeLoc().getBeginLoc(),
10316                   diag::err_auto_different_deductions)
10317                << (unsigned)AT->getKeyword()
10318                << Deduced << DeducedDecl->getDeclName()
10319                << U << D->getDeclName()
10320                << DeducedDecl->getInit()->getSourceRange()
10321                << D->getInit()->getSourceRange();
10322              D->setInvalidDecl();
10323              break;
10324            }
10325          }
10326        }
10327      }
10328    }
10329  
10330    ActOnDocumentableDecls(Group);
10331  
10332    return DeclGroupPtrTy::make(
10333        DeclGroupRef::Create(Context, Group.data(), Group.size()));
10334  }
10335  
ActOnDocumentableDecl(Decl * D)10336  void Sema::ActOnDocumentableDecl(Decl *D) {
10337    ActOnDocumentableDecls(D);
10338  }
10339  
ActOnDocumentableDecls(ArrayRef<Decl * > Group)10340  void Sema::ActOnDocumentableDecls(ArrayRef<Decl *> Group) {
10341    // Don't parse the comment if Doxygen diagnostics are ignored.
10342    if (Group.empty() || !Group[0])
10343      return;
10344  
10345    if (Diags.isIgnored(diag::warn_doc_param_not_found,
10346                        Group[0]->getLocation()) &&
10347        Diags.isIgnored(diag::warn_unknown_comment_command_name,
10348                        Group[0]->getLocation()))
10349      return;
10350  
10351    if (Group.size() >= 2) {
10352      // This is a decl group.  Normally it will contain only declarations
10353      // produced from declarator list.  But in case we have any definitions or
10354      // additional declaration references:
10355      //   'typedef struct S {} S;'
10356      //   'typedef struct S *S;'
10357      //   'struct S *pS;'
10358      // FinalizeDeclaratorGroup adds these as separate declarations.
10359      Decl *MaybeTagDecl = Group[0];
10360      if (MaybeTagDecl && isa<TagDecl>(MaybeTagDecl)) {
10361        Group = Group.slice(1);
10362      }
10363    }
10364  
10365    // See if there are any new comments that are not attached to a decl.
10366    ArrayRef<RawComment *> Comments = Context.getRawCommentList().getComments();
10367    if (!Comments.empty() &&
10368        !Comments.back()->isAttached()) {
10369      // There is at least one comment that not attached to a decl.
10370      // Maybe it should be attached to one of these decls?
10371      //
10372      // Note that this way we pick up not only comments that precede the
10373      // declaration, but also comments that *follow* the declaration -- thanks to
10374      // the lookahead in the lexer: we've consumed the semicolon and looked
10375      // ahead through comments.
10376      for (unsigned i = 0, e = Group.size(); i != e; ++i)
10377        Context.getCommentForDecl(Group[i], &PP);
10378    }
10379  }
10380  
10381  /// ActOnParamDeclarator - Called from Parser::ParseFunctionDeclarator()
10382  /// to introduce parameters into function prototype scope.
ActOnParamDeclarator(Scope * S,Declarator & D)10383  Decl *Sema::ActOnParamDeclarator(Scope *S, Declarator &D) {
10384    const DeclSpec &DS = D.getDeclSpec();
10385  
10386    // Verify C99 6.7.5.3p2: The only SCS allowed is 'register'.
10387  
10388    // C++03 [dcl.stc]p2 also permits 'auto'.
10389    StorageClass SC = SC_None;
10390    if (DS.getStorageClassSpec() == DeclSpec::SCS_register) {
10391      SC = SC_Register;
10392    } else if (getLangOpts().CPlusPlus &&
10393               DS.getStorageClassSpec() == DeclSpec::SCS_auto) {
10394      SC = SC_Auto;
10395    } else if (DS.getStorageClassSpec() != DeclSpec::SCS_unspecified) {
10396      Diag(DS.getStorageClassSpecLoc(),
10397           diag::err_invalid_storage_class_in_func_decl);
10398      D.getMutableDeclSpec().ClearStorageClassSpecs();
10399    }
10400  
10401    if (DeclSpec::TSCS TSCS = DS.getThreadStorageClassSpec())
10402      Diag(DS.getThreadStorageClassSpecLoc(), diag::err_invalid_thread)
10403        << DeclSpec::getSpecifierName(TSCS);
10404    if (DS.isConstexprSpecified())
10405      Diag(DS.getConstexprSpecLoc(), diag::err_invalid_constexpr)
10406        << 0;
10407    if (DS.isConceptSpecified())
10408      Diag(DS.getConceptSpecLoc(), diag::err_concept_wrong_decl_kind);
10409  
10410    DiagnoseFunctionSpecifiers(DS);
10411  
10412    TypeSourceInfo *TInfo = GetTypeForDeclarator(D, S);
10413    QualType parmDeclType = TInfo->getType();
10414  
10415    if (getLangOpts().CPlusPlus) {
10416      // Check that there are no default arguments inside the type of this
10417      // parameter.
10418      CheckExtraCXXDefaultArguments(D);
10419  
10420      // Parameter declarators cannot be qualified (C++ [dcl.meaning]p1).
10421      if (D.getCXXScopeSpec().isSet()) {
10422        Diag(D.getIdentifierLoc(), diag::err_qualified_param_declarator)
10423          << D.getCXXScopeSpec().getRange();
10424        D.getCXXScopeSpec().clear();
10425      }
10426    }
10427  
10428    // Ensure we have a valid name
10429    IdentifierInfo *II = nullptr;
10430    if (D.hasName()) {
10431      II = D.getIdentifier();
10432      if (!II) {
10433        Diag(D.getIdentifierLoc(), diag::err_bad_parameter_name)
10434          << GetNameForDeclarator(D).getName();
10435        D.setInvalidType(true);
10436      }
10437    }
10438  
10439    // Check for redeclaration of parameters, e.g. int foo(int x, int x);
10440    if (II) {
10441      LookupResult R(*this, II, D.getIdentifierLoc(), LookupOrdinaryName,
10442                     ForRedeclaration);
10443      LookupName(R, S);
10444      if (R.isSingleResult()) {
10445        NamedDecl *PrevDecl = R.getFoundDecl();
10446        if (PrevDecl->isTemplateParameter()) {
10447          // Maybe we will complain about the shadowed template parameter.
10448          DiagnoseTemplateParameterShadow(D.getIdentifierLoc(), PrevDecl);
10449          // Just pretend that we didn't see the previous declaration.
10450          PrevDecl = nullptr;
10451        } else if (S->isDeclScope(PrevDecl)) {
10452          Diag(D.getIdentifierLoc(), diag::err_param_redefinition) << II;
10453          Diag(PrevDecl->getLocation(), diag::note_previous_declaration);
10454  
10455          // Recover by removing the name
10456          II = nullptr;
10457          D.SetIdentifier(nullptr, D.getIdentifierLoc());
10458          D.setInvalidType(true);
10459        }
10460      }
10461    }
10462  
10463    // Temporarily put parameter variables in the translation unit, not
10464    // the enclosing context.  This prevents them from accidentally
10465    // looking like class members in C++.
10466    ParmVarDecl *New = CheckParameter(Context.getTranslationUnitDecl(),
10467                                      D.getLocStart(),
10468                                      D.getIdentifierLoc(), II,
10469                                      parmDeclType, TInfo,
10470                                      SC);
10471  
10472    if (D.isInvalidType())
10473      New->setInvalidDecl();
10474  
10475    assert(S->isFunctionPrototypeScope());
10476    assert(S->getFunctionPrototypeDepth() >= 1);
10477    New->setScopeInfo(S->getFunctionPrototypeDepth() - 1,
10478                      S->getNextFunctionPrototypeIndex());
10479  
10480    // Add the parameter declaration into this scope.
10481    S->AddDecl(New);
10482    if (II)
10483      IdResolver.AddDecl(New);
10484  
10485    ProcessDeclAttributes(S, New, D);
10486  
10487    if (D.getDeclSpec().isModulePrivateSpecified())
10488      Diag(New->getLocation(), diag::err_module_private_local)
10489        << 1 << New->getDeclName()
10490        << SourceRange(D.getDeclSpec().getModulePrivateSpecLoc())
10491        << FixItHint::CreateRemoval(D.getDeclSpec().getModulePrivateSpecLoc());
10492  
10493    if (New->hasAttr<BlocksAttr>()) {
10494      Diag(New->getLocation(), diag::err_block_on_nonlocal);
10495    }
10496    return New;
10497  }
10498  
10499  /// \brief Synthesizes a variable for a parameter arising from a
10500  /// typedef.
BuildParmVarDeclForTypedef(DeclContext * DC,SourceLocation Loc,QualType T)10501  ParmVarDecl *Sema::BuildParmVarDeclForTypedef(DeclContext *DC,
10502                                                SourceLocation Loc,
10503                                                QualType T) {
10504    /* FIXME: setting StartLoc == Loc.
10505       Would it be worth to modify callers so as to provide proper source
10506       location for the unnamed parameters, embedding the parameter's type? */
10507    ParmVarDecl *Param = ParmVarDecl::Create(Context, DC, Loc, Loc, nullptr,
10508                                  T, Context.getTrivialTypeSourceInfo(T, Loc),
10509                                             SC_None, nullptr);
10510    Param->setImplicit();
10511    return Param;
10512  }
10513  
DiagnoseUnusedParameters(ParmVarDecl * const * Param,ParmVarDecl * const * ParamEnd)10514  void Sema::DiagnoseUnusedParameters(ParmVarDecl * const *Param,
10515                                      ParmVarDecl * const *ParamEnd) {
10516    // Don't diagnose unused-parameter errors in template instantiations; we
10517    // will already have done so in the template itself.
10518    if (!ActiveTemplateInstantiations.empty())
10519      return;
10520  
10521    for (; Param != ParamEnd; ++Param) {
10522      if (!(*Param)->isReferenced() && (*Param)->getDeclName() &&
10523          !(*Param)->hasAttr<UnusedAttr>()) {
10524        Diag((*Param)->getLocation(), diag::warn_unused_parameter)
10525          << (*Param)->getDeclName();
10526      }
10527    }
10528  }
10529  
DiagnoseSizeOfParametersAndReturnValue(ParmVarDecl * const * Param,ParmVarDecl * const * ParamEnd,QualType ReturnTy,NamedDecl * D)10530  void Sema::DiagnoseSizeOfParametersAndReturnValue(ParmVarDecl * const *Param,
10531                                                    ParmVarDecl * const *ParamEnd,
10532                                                    QualType ReturnTy,
10533                                                    NamedDecl *D) {
10534    if (LangOpts.NumLargeByValueCopy == 0) // No check.
10535      return;
10536  
10537    // Warn if the return value is pass-by-value and larger than the specified
10538    // threshold.
10539    if (!ReturnTy->isDependentType() && ReturnTy.isPODType(Context)) {
10540      unsigned Size = Context.getTypeSizeInChars(ReturnTy).getQuantity();
10541      if (Size > LangOpts.NumLargeByValueCopy)
10542        Diag(D->getLocation(), diag::warn_return_value_size)
10543            << D->getDeclName() << Size;
10544    }
10545  
10546    // Warn if any parameter is pass-by-value and larger than the specified
10547    // threshold.
10548    for (; Param != ParamEnd; ++Param) {
10549      QualType T = (*Param)->getType();
10550      if (T->isDependentType() || !T.isPODType(Context))
10551        continue;
10552      unsigned Size = Context.getTypeSizeInChars(T).getQuantity();
10553      if (Size > LangOpts.NumLargeByValueCopy)
10554        Diag((*Param)->getLocation(), diag::warn_parameter_size)
10555            << (*Param)->getDeclName() << Size;
10556    }
10557  }
10558  
CheckParameter(DeclContext * DC,SourceLocation StartLoc,SourceLocation NameLoc,IdentifierInfo * Name,QualType T,TypeSourceInfo * TSInfo,StorageClass SC)10559  ParmVarDecl *Sema::CheckParameter(DeclContext *DC, SourceLocation StartLoc,
10560                                    SourceLocation NameLoc, IdentifierInfo *Name,
10561                                    QualType T, TypeSourceInfo *TSInfo,
10562                                    StorageClass SC) {
10563    // In ARC, infer a lifetime qualifier for appropriate parameter types.
10564    if (getLangOpts().ObjCAutoRefCount &&
10565        T.getObjCLifetime() == Qualifiers::OCL_None &&
10566        T->isObjCLifetimeType()) {
10567  
10568      Qualifiers::ObjCLifetime lifetime;
10569  
10570      // Special cases for arrays:
10571      //   - if it's const, use __unsafe_unretained
10572      //   - otherwise, it's an error
10573      if (T->isArrayType()) {
10574        if (!T.isConstQualified()) {
10575          DelayedDiagnostics.add(
10576              sema::DelayedDiagnostic::makeForbiddenType(
10577              NameLoc, diag::err_arc_array_param_no_ownership, T, false));
10578        }
10579        lifetime = Qualifiers::OCL_ExplicitNone;
10580      } else {
10581        lifetime = T->getObjCARCImplicitLifetime();
10582      }
10583      T = Context.getLifetimeQualifiedType(T, lifetime);
10584    }
10585  
10586    ParmVarDecl *New = ParmVarDecl::Create(Context, DC, StartLoc, NameLoc, Name,
10587                                           Context.getAdjustedParameterType(T),
10588                                           TSInfo, SC, nullptr);
10589  
10590    // Parameters can not be abstract class types.
10591    // For record types, this is done by the AbstractClassUsageDiagnoser once
10592    // the class has been completely parsed.
10593    if (!CurContext->isRecord() &&
10594        RequireNonAbstractType(NameLoc, T, diag::err_abstract_type_in_decl,
10595                               AbstractParamType))
10596      New->setInvalidDecl();
10597  
10598    // Parameter declarators cannot be interface types. All ObjC objects are
10599    // passed by reference.
10600    if (T->isObjCObjectType()) {
10601      SourceLocation TypeEndLoc = TSInfo->getTypeLoc().getLocEnd();
10602      Diag(NameLoc,
10603           diag::err_object_cannot_be_passed_returned_by_value) << 1 << T
10604        << FixItHint::CreateInsertion(TypeEndLoc, "*");
10605      T = Context.getObjCObjectPointerType(T);
10606      New->setType(T);
10607    }
10608  
10609    // ISO/IEC TR 18037 S6.7.3: "The type of an object with automatic storage
10610    // duration shall not be qualified by an address-space qualifier."
10611    // Since all parameters have automatic store duration, they can not have
10612    // an address space.
10613    if (T.getAddressSpace() != 0) {
10614      // OpenCL allows function arguments declared to be an array of a type
10615      // to be qualified with an address space.
10616      if (!(getLangOpts().OpenCL && T->isArrayType())) {
10617        Diag(NameLoc, diag::err_arg_with_address_space);
10618        New->setInvalidDecl();
10619      }
10620    }
10621  
10622    return New;
10623  }
10624  
ActOnFinishKNRParamDeclarations(Scope * S,Declarator & D,SourceLocation LocAfterDecls)10625  void Sema::ActOnFinishKNRParamDeclarations(Scope *S, Declarator &D,
10626                                             SourceLocation LocAfterDecls) {
10627    DeclaratorChunk::FunctionTypeInfo &FTI = D.getFunctionTypeInfo();
10628  
10629    // Verify 6.9.1p6: 'every identifier in the identifier list shall be declared'
10630    // for a K&R function.
10631    if (!FTI.hasPrototype) {
10632      for (int i = FTI.NumParams; i != 0; /* decrement in loop */) {
10633        --i;
10634        if (FTI.Params[i].Param == nullptr) {
10635          SmallString<256> Code;
10636          llvm::raw_svector_ostream(Code)
10637              << "  int " << FTI.Params[i].Ident->getName() << ";\n";
10638          Diag(FTI.Params[i].IdentLoc, diag::ext_param_not_declared)
10639              << FTI.Params[i].Ident
10640              << FixItHint::CreateInsertion(LocAfterDecls, Code);
10641  
10642          // Implicitly declare the argument as type 'int' for lack of a better
10643          // type.
10644          AttributeFactory attrs;
10645          DeclSpec DS(attrs);
10646          const char* PrevSpec; // unused
10647          unsigned DiagID; // unused
10648          DS.SetTypeSpecType(DeclSpec::TST_int, FTI.Params[i].IdentLoc, PrevSpec,
10649                             DiagID, Context.getPrintingPolicy());
10650          // Use the identifier location for the type source range.
10651          DS.SetRangeStart(FTI.Params[i].IdentLoc);
10652          DS.SetRangeEnd(FTI.Params[i].IdentLoc);
10653          Declarator ParamD(DS, Declarator::KNRTypeListContext);
10654          ParamD.SetIdentifier(FTI.Params[i].Ident, FTI.Params[i].IdentLoc);
10655          FTI.Params[i].Param = ActOnParamDeclarator(S, ParamD);
10656        }
10657      }
10658    }
10659  }
10660  
10661  Decl *
ActOnStartOfFunctionDef(Scope * FnBodyScope,Declarator & D,MultiTemplateParamsArg TemplateParameterLists,SkipBodyInfo * SkipBody)10662  Sema::ActOnStartOfFunctionDef(Scope *FnBodyScope, Declarator &D,
10663                                MultiTemplateParamsArg TemplateParameterLists,
10664                                SkipBodyInfo *SkipBody) {
10665    assert(getCurFunctionDecl() == nullptr && "Function parsing confused");
10666    assert(D.isFunctionDeclarator() && "Not a function declarator!");
10667    Scope *ParentScope = FnBodyScope->getParent();
10668  
10669    D.setFunctionDefinitionKind(FDK_Definition);
10670    Decl *DP = HandleDeclarator(ParentScope, D, TemplateParameterLists);
10671    return ActOnStartOfFunctionDef(FnBodyScope, DP, SkipBody);
10672  }
10673  
ActOnFinishInlineMethodDef(CXXMethodDecl * D)10674  void Sema::ActOnFinishInlineMethodDef(CXXMethodDecl *D) {
10675    Consumer.HandleInlineMethodDefinition(D);
10676  }
10677  
ShouldWarnAboutMissingPrototype(const FunctionDecl * FD,const FunctionDecl * & PossibleZeroParamPrototype)10678  static bool ShouldWarnAboutMissingPrototype(const FunctionDecl *FD,
10679                               const FunctionDecl*& PossibleZeroParamPrototype) {
10680    // Don't warn about invalid declarations.
10681    if (FD->isInvalidDecl())
10682      return false;
10683  
10684    // Or declarations that aren't global.
10685    if (!FD->isGlobal())
10686      return false;
10687  
10688    // Don't warn about C++ member functions.
10689    if (isa<CXXMethodDecl>(FD))
10690      return false;
10691  
10692    // Don't warn about 'main'.
10693    if (FD->isMain())
10694      return false;
10695  
10696    // Don't warn about inline functions.
10697    if (FD->isInlined())
10698      return false;
10699  
10700    // Don't warn about function templates.
10701    if (FD->getDescribedFunctionTemplate())
10702      return false;
10703  
10704    // Don't warn about function template specializations.
10705    if (FD->isFunctionTemplateSpecialization())
10706      return false;
10707  
10708    // Don't warn for OpenCL kernels.
10709    if (FD->hasAttr<OpenCLKernelAttr>())
10710      return false;
10711  
10712    // Don't warn on explicitly deleted functions.
10713    if (FD->isDeleted())
10714      return false;
10715  
10716    bool MissingPrototype = true;
10717    for (const FunctionDecl *Prev = FD->getPreviousDecl();
10718         Prev; Prev = Prev->getPreviousDecl()) {
10719      // Ignore any declarations that occur in function or method
10720      // scope, because they aren't visible from the header.
10721      if (Prev->getLexicalDeclContext()->isFunctionOrMethod())
10722        continue;
10723  
10724      MissingPrototype = !Prev->getType()->isFunctionProtoType();
10725      if (FD->getNumParams() == 0)
10726        PossibleZeroParamPrototype = Prev;
10727      break;
10728    }
10729  
10730    return MissingPrototype;
10731  }
10732  
10733  void
CheckForFunctionRedefinition(FunctionDecl * FD,const FunctionDecl * EffectiveDefinition,SkipBodyInfo * SkipBody)10734  Sema::CheckForFunctionRedefinition(FunctionDecl *FD,
10735                                     const FunctionDecl *EffectiveDefinition,
10736                                     SkipBodyInfo *SkipBody) {
10737    // Don't complain if we're in GNU89 mode and the previous definition
10738    // was an extern inline function.
10739    const FunctionDecl *Definition = EffectiveDefinition;
10740    if (!Definition)
10741      if (!FD->isDefined(Definition))
10742        return;
10743  
10744    if (canRedefineFunction(Definition, getLangOpts()))
10745      return;
10746  
10747    // If we don't have a visible definition of the function, and it's inline or
10748    // a template, skip the new definition.
10749    if (SkipBody && !hasVisibleDefinition(Definition) &&
10750        (Definition->getFormalLinkage() == InternalLinkage ||
10751         Definition->isInlined() ||
10752         Definition->getDescribedFunctionTemplate() ||
10753         Definition->getNumTemplateParameterLists())) {
10754      SkipBody->ShouldSkip = true;
10755      if (auto *TD = Definition->getDescribedFunctionTemplate())
10756        makeMergedDefinitionVisible(TD, FD->getLocation());
10757      else
10758        makeMergedDefinitionVisible(const_cast<FunctionDecl*>(Definition),
10759                                    FD->getLocation());
10760      return;
10761    }
10762  
10763    if (getLangOpts().GNUMode && Definition->isInlineSpecified() &&
10764        Definition->getStorageClass() == SC_Extern)
10765      Diag(FD->getLocation(), diag::err_redefinition_extern_inline)
10766          << FD->getDeclName() << getLangOpts().CPlusPlus;
10767    else
10768      Diag(FD->getLocation(), diag::err_redefinition) << FD->getDeclName();
10769  
10770    Diag(Definition->getLocation(), diag::note_previous_definition);
10771    FD->setInvalidDecl();
10772  }
10773  
10774  
RebuildLambdaScopeInfo(CXXMethodDecl * CallOperator,Sema & S)10775  static void RebuildLambdaScopeInfo(CXXMethodDecl *CallOperator,
10776                                     Sema &S) {
10777    CXXRecordDecl *const LambdaClass = CallOperator->getParent();
10778  
10779    LambdaScopeInfo *LSI = S.PushLambdaScope();
10780    LSI->CallOperator = CallOperator;
10781    LSI->Lambda = LambdaClass;
10782    LSI->ReturnType = CallOperator->getReturnType();
10783    const LambdaCaptureDefault LCD = LambdaClass->getLambdaCaptureDefault();
10784  
10785    if (LCD == LCD_None)
10786      LSI->ImpCaptureStyle = CapturingScopeInfo::ImpCap_None;
10787    else if (LCD == LCD_ByCopy)
10788      LSI->ImpCaptureStyle = CapturingScopeInfo::ImpCap_LambdaByval;
10789    else if (LCD == LCD_ByRef)
10790      LSI->ImpCaptureStyle = CapturingScopeInfo::ImpCap_LambdaByref;
10791    DeclarationNameInfo DNI = CallOperator->getNameInfo();
10792  
10793    LSI->IntroducerRange = DNI.getCXXOperatorNameRange();
10794    LSI->Mutable = !CallOperator->isConst();
10795  
10796    // Add the captures to the LSI so they can be noted as already
10797    // captured within tryCaptureVar.
10798    auto I = LambdaClass->field_begin();
10799    for (const auto &C : LambdaClass->captures()) {
10800      if (C.capturesVariable()) {
10801        VarDecl *VD = C.getCapturedVar();
10802        if (VD->isInitCapture())
10803          S.CurrentInstantiationScope->InstantiatedLocal(VD, VD);
10804        QualType CaptureType = VD->getType();
10805        const bool ByRef = C.getCaptureKind() == LCK_ByRef;
10806        LSI->addCapture(VD, /*IsBlock*/false, ByRef,
10807            /*RefersToEnclosingVariableOrCapture*/true, C.getLocation(),
10808            /*EllipsisLoc*/C.isPackExpansion()
10809                           ? C.getEllipsisLoc() : SourceLocation(),
10810            CaptureType, /*Expr*/ nullptr);
10811  
10812      } else if (C.capturesThis()) {
10813        LSI->addThisCapture(/*Nested*/ false, C.getLocation(),
10814                                S.getCurrentThisType(), /*Expr*/ nullptr);
10815      } else {
10816        LSI->addVLATypeCapture(C.getLocation(), I->getType());
10817      }
10818      ++I;
10819    }
10820  }
10821  
ActOnStartOfFunctionDef(Scope * FnBodyScope,Decl * D,SkipBodyInfo * SkipBody)10822  Decl *Sema::ActOnStartOfFunctionDef(Scope *FnBodyScope, Decl *D,
10823                                      SkipBodyInfo *SkipBody) {
10824    // Clear the last template instantiation error context.
10825    LastTemplateInstantiationErrorContext = ActiveTemplateInstantiation();
10826  
10827    if (!D)
10828      return D;
10829    FunctionDecl *FD = nullptr;
10830  
10831    if (FunctionTemplateDecl *FunTmpl = dyn_cast<FunctionTemplateDecl>(D))
10832      FD = FunTmpl->getTemplatedDecl();
10833    else
10834      FD = cast<FunctionDecl>(D);
10835  
10836    // See if this is a redefinition.
10837    if (!FD->isLateTemplateParsed()) {
10838      CheckForFunctionRedefinition(FD, nullptr, SkipBody);
10839  
10840      // If we're skipping the body, we're done. Don't enter the scope.
10841      if (SkipBody && SkipBody->ShouldSkip)
10842        return D;
10843    }
10844  
10845    // If we are instantiating a generic lambda call operator, push
10846    // a LambdaScopeInfo onto the function stack.  But use the information
10847    // that's already been calculated (ActOnLambdaExpr) to prime the current
10848    // LambdaScopeInfo.
10849    // When the template operator is being specialized, the LambdaScopeInfo,
10850    // has to be properly restored so that tryCaptureVariable doesn't try
10851    // and capture any new variables. In addition when calculating potential
10852    // captures during transformation of nested lambdas, it is necessary to
10853    // have the LSI properly restored.
10854    if (isGenericLambdaCallOperatorSpecialization(FD)) {
10855      assert(ActiveTemplateInstantiations.size() &&
10856        "There should be an active template instantiation on the stack "
10857        "when instantiating a generic lambda!");
10858      RebuildLambdaScopeInfo(cast<CXXMethodDecl>(D), *this);
10859    }
10860    else
10861      // Enter a new function scope
10862      PushFunctionScope();
10863  
10864    // Builtin functions cannot be defined.
10865    if (unsigned BuiltinID = FD->getBuiltinID()) {
10866      if (!Context.BuiltinInfo.isPredefinedLibFunction(BuiltinID) &&
10867          !Context.BuiltinInfo.isPredefinedRuntimeFunction(BuiltinID)) {
10868        Diag(FD->getLocation(), diag::err_builtin_definition) << FD;
10869        FD->setInvalidDecl();
10870      }
10871    }
10872  
10873    // The return type of a function definition must be complete
10874    // (C99 6.9.1p3, C++ [dcl.fct]p6).
10875    QualType ResultType = FD->getReturnType();
10876    if (!ResultType->isDependentType() && !ResultType->isVoidType() &&
10877        !FD->isInvalidDecl() &&
10878        RequireCompleteType(FD->getLocation(), ResultType,
10879                            diag::err_func_def_incomplete_result))
10880      FD->setInvalidDecl();
10881  
10882    if (FnBodyScope)
10883      PushDeclContext(FnBodyScope, FD);
10884  
10885    // Check the validity of our function parameters
10886    CheckParmsForFunctionDef(FD->param_begin(), FD->param_end(),
10887                             /*CheckParameterNames=*/true);
10888  
10889    // Introduce our parameters into the function scope
10890    for (auto Param : FD->params()) {
10891      Param->setOwningFunction(FD);
10892  
10893      // If this has an identifier, add it to the scope stack.
10894      if (Param->getIdentifier() && FnBodyScope) {
10895        CheckShadow(FnBodyScope, Param);
10896  
10897        PushOnScopeChains(Param, FnBodyScope);
10898      }
10899    }
10900  
10901    // If we had any tags defined in the function prototype,
10902    // introduce them into the function scope.
10903    if (FnBodyScope) {
10904      for (ArrayRef<NamedDecl *>::iterator
10905               I = FD->getDeclsInPrototypeScope().begin(),
10906               E = FD->getDeclsInPrototypeScope().end();
10907           I != E; ++I) {
10908        NamedDecl *D = *I;
10909  
10910        // Some of these decls (like enums) may have been pinned to the
10911        // translation unit for lack of a real context earlier. If so, remove
10912        // from the translation unit and reattach to the current context.
10913        if (D->getLexicalDeclContext() == Context.getTranslationUnitDecl()) {
10914          // Is the decl actually in the context?
10915          for (const auto *DI : Context.getTranslationUnitDecl()->decls()) {
10916            if (DI == D) {
10917              Context.getTranslationUnitDecl()->removeDecl(D);
10918              break;
10919            }
10920          }
10921          // Either way, reassign the lexical decl context to our FunctionDecl.
10922          D->setLexicalDeclContext(CurContext);
10923        }
10924  
10925        // If the decl has a non-null name, make accessible in the current scope.
10926        if (!D->getName().empty())
10927          PushOnScopeChains(D, FnBodyScope, /*AddToContext=*/false);
10928  
10929        // Similarly, dive into enums and fish their constants out, making them
10930        // accessible in this scope.
10931        if (auto *ED = dyn_cast<EnumDecl>(D)) {
10932          for (auto *EI : ED->enumerators())
10933            PushOnScopeChains(EI, FnBodyScope, /*AddToContext=*/false);
10934        }
10935      }
10936    }
10937  
10938    // Ensure that the function's exception specification is instantiated.
10939    if (const FunctionProtoType *FPT = FD->getType()->getAs<FunctionProtoType>())
10940      ResolveExceptionSpec(D->getLocation(), FPT);
10941  
10942    // dllimport cannot be applied to non-inline function definitions.
10943    if (FD->hasAttr<DLLImportAttr>() && !FD->isInlined() &&
10944        !FD->isTemplateInstantiation()) {
10945      assert(!FD->hasAttr<DLLExportAttr>());
10946      Diag(FD->getLocation(), diag::err_attribute_dllimport_function_definition);
10947      FD->setInvalidDecl();
10948      return D;
10949    }
10950    // We want to attach documentation to original Decl (which might be
10951    // a function template).
10952    ActOnDocumentableDecl(D);
10953    if (getCurLexicalContext()->isObjCContainer() &&
10954        getCurLexicalContext()->getDeclKind() != Decl::ObjCCategoryImpl &&
10955        getCurLexicalContext()->getDeclKind() != Decl::ObjCImplementation)
10956      Diag(FD->getLocation(), diag::warn_function_def_in_objc_container);
10957  
10958    return D;
10959  }
10960  
10961  /// \brief Given the set of return statements within a function body,
10962  /// compute the variables that are subject to the named return value
10963  /// optimization.
10964  ///
10965  /// Each of the variables that is subject to the named return value
10966  /// optimization will be marked as NRVO variables in the AST, and any
10967  /// return statement that has a marked NRVO variable as its NRVO candidate can
10968  /// use the named return value optimization.
10969  ///
10970  /// This function applies a very simplistic algorithm for NRVO: if every return
10971  /// statement in the scope of a variable has the same NRVO candidate, that
10972  /// candidate is an NRVO variable.
computeNRVO(Stmt * Body,FunctionScopeInfo * Scope)10973  void Sema::computeNRVO(Stmt *Body, FunctionScopeInfo *Scope) {
10974    ReturnStmt **Returns = Scope->Returns.data();
10975  
10976    for (unsigned I = 0, E = Scope->Returns.size(); I != E; ++I) {
10977      if (const VarDecl *NRVOCandidate = Returns[I]->getNRVOCandidate()) {
10978        if (!NRVOCandidate->isNRVOVariable())
10979          Returns[I]->setNRVOCandidate(nullptr);
10980      }
10981    }
10982  }
10983  
canDelayFunctionBody(const Declarator & D)10984  bool Sema::canDelayFunctionBody(const Declarator &D) {
10985    // We can't delay parsing the body of a constexpr function template (yet).
10986    if (D.getDeclSpec().isConstexprSpecified())
10987      return false;
10988  
10989    // We can't delay parsing the body of a function template with a deduced
10990    // return type (yet).
10991    if (D.getDeclSpec().containsPlaceholderType()) {
10992      // If the placeholder introduces a non-deduced trailing return type,
10993      // we can still delay parsing it.
10994      if (D.getNumTypeObjects()) {
10995        const auto &Outer = D.getTypeObject(D.getNumTypeObjects() - 1);
10996        if (Outer.Kind == DeclaratorChunk::Function &&
10997            Outer.Fun.hasTrailingReturnType()) {
10998          QualType Ty = GetTypeFromParser(Outer.Fun.getTrailingReturnType());
10999          return Ty.isNull() || !Ty->isUndeducedType();
11000        }
11001      }
11002      return false;
11003    }
11004  
11005    return true;
11006  }
11007  
canSkipFunctionBody(Decl * D)11008  bool Sema::canSkipFunctionBody(Decl *D) {
11009    // We cannot skip the body of a function (or function template) which is
11010    // constexpr, since we may need to evaluate its body in order to parse the
11011    // rest of the file.
11012    // We cannot skip the body of a function with an undeduced return type,
11013    // because any callers of that function need to know the type.
11014    if (const FunctionDecl *FD = D->getAsFunction())
11015      if (FD->isConstexpr() || FD->getReturnType()->isUndeducedType())
11016        return false;
11017    return Consumer.shouldSkipFunctionBody(D);
11018  }
11019  
ActOnSkippedFunctionBody(Decl * Decl)11020  Decl *Sema::ActOnSkippedFunctionBody(Decl *Decl) {
11021    if (FunctionDecl *FD = dyn_cast_or_null<FunctionDecl>(Decl))
11022      FD->setHasSkippedBody();
11023    else if (ObjCMethodDecl *MD = dyn_cast_or_null<ObjCMethodDecl>(Decl))
11024      MD->setHasSkippedBody();
11025    return ActOnFinishFunctionBody(Decl, nullptr);
11026  }
11027  
ActOnFinishFunctionBody(Decl * D,Stmt * BodyArg)11028  Decl *Sema::ActOnFinishFunctionBody(Decl *D, Stmt *BodyArg) {
11029    return ActOnFinishFunctionBody(D, BodyArg, false);
11030  }
11031  
ActOnFinishFunctionBody(Decl * dcl,Stmt * Body,bool IsInstantiation)11032  Decl *Sema::ActOnFinishFunctionBody(Decl *dcl, Stmt *Body,
11033                                      bool IsInstantiation) {
11034    FunctionDecl *FD = dcl ? dcl->getAsFunction() : nullptr;
11035  
11036    sema::AnalysisBasedWarnings::Policy WP = AnalysisWarnings.getDefaultPolicy();
11037    sema::AnalysisBasedWarnings::Policy *ActivePolicy = nullptr;
11038  
11039    if (getLangOpts().Coroutines && !getCurFunction()->CoroutineStmts.empty())
11040      CheckCompletedCoroutineBody(FD, Body);
11041  
11042    if (FD) {
11043      FD->setBody(Body);
11044  
11045      if (getLangOpts().CPlusPlus14 && !FD->isInvalidDecl() && Body &&
11046          !FD->isDependentContext() && FD->getReturnType()->isUndeducedType()) {
11047        // If the function has a deduced result type but contains no 'return'
11048        // statements, the result type as written must be exactly 'auto', and
11049        // the deduced result type is 'void'.
11050        if (!FD->getReturnType()->getAs<AutoType>()) {
11051          Diag(dcl->getLocation(), diag::err_auto_fn_no_return_but_not_auto)
11052              << FD->getReturnType();
11053          FD->setInvalidDecl();
11054        } else {
11055          // Substitute 'void' for the 'auto' in the type.
11056          TypeLoc ResultType = getReturnTypeLoc(FD);
11057          Context.adjustDeducedFunctionResultType(
11058              FD, SubstAutoType(ResultType.getType(), Context.VoidTy));
11059        }
11060      } else if (getLangOpts().CPlusPlus11 && isLambdaCallOperator(FD)) {
11061        auto *LSI = getCurLambda();
11062        if (LSI->HasImplicitReturnType) {
11063          deduceClosureReturnType(*LSI);
11064  
11065          // C++11 [expr.prim.lambda]p4:
11066          //   [...] if there are no return statements in the compound-statement
11067          //   [the deduced type is] the type void
11068          QualType RetType =
11069              LSI->ReturnType.isNull() ? Context.VoidTy : LSI->ReturnType;
11070  
11071          // Update the return type to the deduced type.
11072          const FunctionProtoType *Proto =
11073              FD->getType()->getAs<FunctionProtoType>();
11074          FD->setType(Context.getFunctionType(RetType, Proto->getParamTypes(),
11075                                              Proto->getExtProtoInfo()));
11076        }
11077      }
11078  
11079      // The only way to be included in UndefinedButUsed is if there is an
11080      // ODR use before the definition. Avoid the expensive map lookup if this
11081      // is the first declaration.
11082      if (!FD->isFirstDecl() && FD->getPreviousDecl()->isUsed()) {
11083        if (!FD->isExternallyVisible())
11084          UndefinedButUsed.erase(FD);
11085        else if (FD->isInlined() &&
11086                 !LangOpts.GNUInline &&
11087                 (!FD->getPreviousDecl()->hasAttr<GNUInlineAttr>()))
11088          UndefinedButUsed.erase(FD);
11089      }
11090  
11091      // If the function implicitly returns zero (like 'main') or is naked,
11092      // don't complain about missing return statements.
11093      if (FD->hasImplicitReturnZero() || FD->hasAttr<NakedAttr>())
11094        WP.disableCheckFallThrough();
11095  
11096      // MSVC permits the use of pure specifier (=0) on function definition,
11097      // defined at class scope, warn about this non-standard construct.
11098      if (getLangOpts().MicrosoftExt && FD->isPure() && FD->isCanonicalDecl())
11099        Diag(FD->getLocation(), diag::ext_pure_function_definition);
11100  
11101      if (!FD->isInvalidDecl()) {
11102        // Don't diagnose unused parameters of defaulted or deleted functions.
11103        if (!FD->isDeleted() && !FD->isDefaulted())
11104          DiagnoseUnusedParameters(FD->param_begin(), FD->param_end());
11105        DiagnoseSizeOfParametersAndReturnValue(FD->param_begin(), FD->param_end(),
11106                                               FD->getReturnType(), FD);
11107  
11108        // If this is a structor, we need a vtable.
11109        if (CXXConstructorDecl *Constructor = dyn_cast<CXXConstructorDecl>(FD))
11110          MarkVTableUsed(FD->getLocation(), Constructor->getParent());
11111        else if (CXXDestructorDecl *Destructor = dyn_cast<CXXDestructorDecl>(FD))
11112          MarkVTableUsed(FD->getLocation(), Destructor->getParent());
11113  
11114        // Try to apply the named return value optimization. We have to check
11115        // if we can do this here because lambdas keep return statements around
11116        // to deduce an implicit return type.
11117        if (getLangOpts().CPlusPlus && FD->getReturnType()->isRecordType() &&
11118            !FD->isDependentContext())
11119          computeNRVO(Body, getCurFunction());
11120      }
11121  
11122      // GNU warning -Wmissing-prototypes:
11123      //   Warn if a global function is defined without a previous
11124      //   prototype declaration. This warning is issued even if the
11125      //   definition itself provides a prototype. The aim is to detect
11126      //   global functions that fail to be declared in header files.
11127      const FunctionDecl *PossibleZeroParamPrototype = nullptr;
11128      if (ShouldWarnAboutMissingPrototype(FD, PossibleZeroParamPrototype)) {
11129        Diag(FD->getLocation(), diag::warn_missing_prototype) << FD;
11130  
11131        if (PossibleZeroParamPrototype) {
11132          // We found a declaration that is not a prototype,
11133          // but that could be a zero-parameter prototype
11134          if (TypeSourceInfo *TI =
11135                  PossibleZeroParamPrototype->getTypeSourceInfo()) {
11136            TypeLoc TL = TI->getTypeLoc();
11137            if (FunctionNoProtoTypeLoc FTL = TL.getAs<FunctionNoProtoTypeLoc>())
11138              Diag(PossibleZeroParamPrototype->getLocation(),
11139                   diag::note_declaration_not_a_prototype)
11140                  << PossibleZeroParamPrototype
11141                  << FixItHint::CreateInsertion(FTL.getRParenLoc(), "void");
11142          }
11143        }
11144      }
11145  
11146      if (auto *MD = dyn_cast<CXXMethodDecl>(FD)) {
11147        const CXXMethodDecl *KeyFunction;
11148        if (MD->isOutOfLine() && (MD = MD->getCanonicalDecl()) &&
11149            MD->isVirtual() &&
11150            (KeyFunction = Context.getCurrentKeyFunction(MD->getParent())) &&
11151            MD == KeyFunction->getCanonicalDecl()) {
11152          // Update the key-function state if necessary for this ABI.
11153          if (FD->isInlined() &&
11154              !Context.getTargetInfo().getCXXABI().canKeyFunctionBeInline()) {
11155            Context.setNonKeyFunction(MD);
11156  
11157            // If the newly-chosen key function is already defined, then we
11158            // need to mark the vtable as used retroactively.
11159            KeyFunction = Context.getCurrentKeyFunction(MD->getParent());
11160            const FunctionDecl *Definition;
11161            if (KeyFunction && KeyFunction->isDefined(Definition))
11162              MarkVTableUsed(Definition->getLocation(), MD->getParent(), true);
11163          } else {
11164            // We just defined they key function; mark the vtable as used.
11165            MarkVTableUsed(FD->getLocation(), MD->getParent(), true);
11166          }
11167        }
11168      }
11169  
11170      assert((FD == getCurFunctionDecl() || getCurLambda()->CallOperator == FD) &&
11171             "Function parsing confused");
11172    } else if (ObjCMethodDecl *MD = dyn_cast_or_null<ObjCMethodDecl>(dcl)) {
11173      assert(MD == getCurMethodDecl() && "Method parsing confused");
11174      MD->setBody(Body);
11175      if (!MD->isInvalidDecl()) {
11176        DiagnoseUnusedParameters(MD->param_begin(), MD->param_end());
11177        DiagnoseSizeOfParametersAndReturnValue(MD->param_begin(), MD->param_end(),
11178                                               MD->getReturnType(), MD);
11179  
11180        if (Body)
11181          computeNRVO(Body, getCurFunction());
11182      }
11183      if (getCurFunction()->ObjCShouldCallSuper) {
11184        Diag(MD->getLocEnd(), diag::warn_objc_missing_super_call)
11185          << MD->getSelector().getAsString();
11186        getCurFunction()->ObjCShouldCallSuper = false;
11187      }
11188      if (getCurFunction()->ObjCWarnForNoDesignatedInitChain) {
11189        const ObjCMethodDecl *InitMethod = nullptr;
11190        bool isDesignated =
11191            MD->isDesignatedInitializerForTheInterface(&InitMethod);
11192        assert(isDesignated && InitMethod);
11193        (void)isDesignated;
11194  
11195        auto superIsNSObject = [&](const ObjCMethodDecl *MD) {
11196          auto IFace = MD->getClassInterface();
11197          if (!IFace)
11198            return false;
11199          auto SuperD = IFace->getSuperClass();
11200          if (!SuperD)
11201            return false;
11202          return SuperD->getIdentifier() ==
11203              NSAPIObj->getNSClassId(NSAPI::ClassId_NSObject);
11204        };
11205        // Don't issue this warning for unavailable inits or direct subclasses
11206        // of NSObject.
11207        if (!MD->isUnavailable() && !superIsNSObject(MD)) {
11208          Diag(MD->getLocation(),
11209               diag::warn_objc_designated_init_missing_super_call);
11210          Diag(InitMethod->getLocation(),
11211               diag::note_objc_designated_init_marked_here);
11212        }
11213        getCurFunction()->ObjCWarnForNoDesignatedInitChain = false;
11214      }
11215      if (getCurFunction()->ObjCWarnForNoInitDelegation) {
11216        // Don't issue this warning for unavaialable inits.
11217        if (!MD->isUnavailable())
11218          Diag(MD->getLocation(),
11219               diag::warn_objc_secondary_init_missing_init_call);
11220        getCurFunction()->ObjCWarnForNoInitDelegation = false;
11221      }
11222    } else {
11223      return nullptr;
11224    }
11225  
11226    assert(!getCurFunction()->ObjCShouldCallSuper &&
11227           "This should only be set for ObjC methods, which should have been "
11228           "handled in the block above.");
11229  
11230    // Verify and clean out per-function state.
11231    if (Body && (!FD || !FD->isDefaulted())) {
11232      // C++ constructors that have function-try-blocks can't have return
11233      // statements in the handlers of that block. (C++ [except.handle]p14)
11234      // Verify this.
11235      if (FD && isa<CXXConstructorDecl>(FD) && isa<CXXTryStmt>(Body))
11236        DiagnoseReturnInConstructorExceptionHandler(cast<CXXTryStmt>(Body));
11237  
11238      // Verify that gotos and switch cases don't jump into scopes illegally.
11239      if (getCurFunction()->NeedsScopeChecking() &&
11240          !PP.isCodeCompletionEnabled())
11241        DiagnoseInvalidJumps(Body);
11242  
11243      if (CXXDestructorDecl *Destructor = dyn_cast<CXXDestructorDecl>(dcl)) {
11244        if (!Destructor->getParent()->isDependentType())
11245          CheckDestructor(Destructor);
11246  
11247        MarkBaseAndMemberDestructorsReferenced(Destructor->getLocation(),
11248                                               Destructor->getParent());
11249      }
11250  
11251      // If any errors have occurred, clear out any temporaries that may have
11252      // been leftover. This ensures that these temporaries won't be picked up for
11253      // deletion in some later function.
11254      if (getDiagnostics().hasErrorOccurred() ||
11255          getDiagnostics().getSuppressAllDiagnostics()) {
11256        DiscardCleanupsInEvaluationContext();
11257      }
11258      if (!getDiagnostics().hasUncompilableErrorOccurred() &&
11259          !isa<FunctionTemplateDecl>(dcl)) {
11260        // Since the body is valid, issue any analysis-based warnings that are
11261        // enabled.
11262        ActivePolicy = &WP;
11263      }
11264  
11265      if (!IsInstantiation && FD && FD->isConstexpr() && !FD->isInvalidDecl() &&
11266          (!CheckConstexprFunctionDecl(FD) ||
11267           !CheckConstexprFunctionBody(FD, Body)))
11268        FD->setInvalidDecl();
11269  
11270      if (FD && FD->hasAttr<NakedAttr>()) {
11271        for (const Stmt *S : Body->children()) {
11272          if (!isa<AsmStmt>(S) && !isa<NullStmt>(S)) {
11273            Diag(S->getLocStart(), diag::err_non_asm_stmt_in_naked_function);
11274            Diag(FD->getAttr<NakedAttr>()->getLocation(), diag::note_attribute);
11275            FD->setInvalidDecl();
11276            break;
11277          }
11278        }
11279      }
11280  
11281      assert(ExprCleanupObjects.size() ==
11282                 ExprEvalContexts.back().NumCleanupObjects &&
11283             "Leftover temporaries in function");
11284      assert(!ExprNeedsCleanups && "Unaccounted cleanups in function");
11285      assert(MaybeODRUseExprs.empty() &&
11286             "Leftover expressions for odr-use checking");
11287    }
11288  
11289    if (!IsInstantiation)
11290      PopDeclContext();
11291  
11292    PopFunctionScopeInfo(ActivePolicy, dcl);
11293    // If any errors have occurred, clear out any temporaries that may have
11294    // been leftover. This ensures that these temporaries won't be picked up for
11295    // deletion in some later function.
11296    if (getDiagnostics().hasErrorOccurred()) {
11297      DiscardCleanupsInEvaluationContext();
11298    }
11299  
11300    return dcl;
11301  }
11302  
11303  
11304  /// When we finish delayed parsing of an attribute, we must attach it to the
11305  /// relevant Decl.
ActOnFinishDelayedAttribute(Scope * S,Decl * D,ParsedAttributes & Attrs)11306  void Sema::ActOnFinishDelayedAttribute(Scope *S, Decl *D,
11307                                         ParsedAttributes &Attrs) {
11308    // Always attach attributes to the underlying decl.
11309    if (TemplateDecl *TD = dyn_cast<TemplateDecl>(D))
11310      D = TD->getTemplatedDecl();
11311    ProcessDeclAttributeList(S, D, Attrs.getList());
11312  
11313    if (CXXMethodDecl *Method = dyn_cast_or_null<CXXMethodDecl>(D))
11314      if (Method->isStatic())
11315        checkThisInStaticMemberFunctionAttributes(Method);
11316  }
11317  
11318  
11319  /// ImplicitlyDefineFunction - An undeclared identifier was used in a function
11320  /// call, forming a call to an implicitly defined function (per C99 6.5.1p2).
ImplicitlyDefineFunction(SourceLocation Loc,IdentifierInfo & II,Scope * S)11321  NamedDecl *Sema::ImplicitlyDefineFunction(SourceLocation Loc,
11322                                            IdentifierInfo &II, Scope *S) {
11323    // Before we produce a declaration for an implicitly defined
11324    // function, see whether there was a locally-scoped declaration of
11325    // this name as a function or variable. If so, use that
11326    // (non-visible) declaration, and complain about it.
11327    if (NamedDecl *ExternCPrev = findLocallyScopedExternCDecl(&II)) {
11328      Diag(Loc, diag::warn_use_out_of_scope_declaration) << ExternCPrev;
11329      Diag(ExternCPrev->getLocation(), diag::note_previous_declaration);
11330      return ExternCPrev;
11331    }
11332  
11333    // Extension in C99.  Legal in C90, but warn about it.
11334    unsigned diag_id;
11335    if (II.getName().startswith("__builtin_"))
11336      diag_id = diag::warn_builtin_unknown;
11337    else if (getLangOpts().C99)
11338      diag_id = diag::ext_implicit_function_decl;
11339    else
11340      diag_id = diag::warn_implicit_function_decl;
11341    Diag(Loc, diag_id) << &II;
11342  
11343    // Because typo correction is expensive, only do it if the implicit
11344    // function declaration is going to be treated as an error.
11345    if (Diags.getDiagnosticLevel(diag_id, Loc) >= DiagnosticsEngine::Error) {
11346      TypoCorrection Corrected;
11347      if (S &&
11348          (Corrected = CorrectTypo(
11349               DeclarationNameInfo(&II, Loc), LookupOrdinaryName, S, nullptr,
11350               llvm::make_unique<DeclFilterCCC<FunctionDecl>>(), CTK_NonError)))
11351        diagnoseTypo(Corrected, PDiag(diag::note_function_suggestion),
11352                     /*ErrorRecovery*/false);
11353    }
11354  
11355    // Set a Declarator for the implicit definition: int foo();
11356    const char *Dummy;
11357    AttributeFactory attrFactory;
11358    DeclSpec DS(attrFactory);
11359    unsigned DiagID;
11360    bool Error = DS.SetTypeSpecType(DeclSpec::TST_int, Loc, Dummy, DiagID,
11361                                    Context.getPrintingPolicy());
11362    (void)Error; // Silence warning.
11363    assert(!Error && "Error setting up implicit decl!");
11364    SourceLocation NoLoc;
11365    Declarator D(DS, Declarator::BlockContext);
11366    D.AddTypeInfo(DeclaratorChunk::getFunction(/*HasProto=*/false,
11367                                               /*IsAmbiguous=*/false,
11368                                               /*LParenLoc=*/NoLoc,
11369                                               /*Params=*/nullptr,
11370                                               /*NumParams=*/0,
11371                                               /*EllipsisLoc=*/NoLoc,
11372                                               /*RParenLoc=*/NoLoc,
11373                                               /*TypeQuals=*/0,
11374                                               /*RefQualifierIsLvalueRef=*/true,
11375                                               /*RefQualifierLoc=*/NoLoc,
11376                                               /*ConstQualifierLoc=*/NoLoc,
11377                                               /*VolatileQualifierLoc=*/NoLoc,
11378                                               /*RestrictQualifierLoc=*/NoLoc,
11379                                               /*MutableLoc=*/NoLoc,
11380                                               EST_None,
11381                                               /*ESpecRange=*/SourceRange(),
11382                                               /*Exceptions=*/nullptr,
11383                                               /*ExceptionRanges=*/nullptr,
11384                                               /*NumExceptions=*/0,
11385                                               /*NoexceptExpr=*/nullptr,
11386                                               /*ExceptionSpecTokens=*/nullptr,
11387                                               Loc, Loc, D),
11388                  DS.getAttributes(),
11389                  SourceLocation());
11390    D.SetIdentifier(&II, Loc);
11391  
11392    // Insert this function into translation-unit scope.
11393  
11394    DeclContext *PrevDC = CurContext;
11395    CurContext = Context.getTranslationUnitDecl();
11396  
11397    FunctionDecl *FD = cast<FunctionDecl>(ActOnDeclarator(TUScope, D));
11398    FD->setImplicit();
11399  
11400    CurContext = PrevDC;
11401  
11402    AddKnownFunctionAttributes(FD);
11403  
11404    return FD;
11405  }
11406  
11407  /// \brief Adds any function attributes that we know a priori based on
11408  /// the declaration of this function.
11409  ///
11410  /// These attributes can apply both to implicitly-declared builtins
11411  /// (like __builtin___printf_chk) or to library-declared functions
11412  /// like NSLog or printf.
11413  ///
11414  /// We need to check for duplicate attributes both here and where user-written
11415  /// attributes are applied to declarations.
AddKnownFunctionAttributes(FunctionDecl * FD)11416  void Sema::AddKnownFunctionAttributes(FunctionDecl *FD) {
11417    if (FD->isInvalidDecl())
11418      return;
11419  
11420    // If this is a built-in function, map its builtin attributes to
11421    // actual attributes.
11422    if (unsigned BuiltinID = FD->getBuiltinID()) {
11423      // Handle printf-formatting attributes.
11424      unsigned FormatIdx;
11425      bool HasVAListArg;
11426      if (Context.BuiltinInfo.isPrintfLike(BuiltinID, FormatIdx, HasVAListArg)) {
11427        if (!FD->hasAttr<FormatAttr>()) {
11428          const char *fmt = "printf";
11429          unsigned int NumParams = FD->getNumParams();
11430          if (FormatIdx < NumParams && // NumParams may be 0 (e.g. vfprintf)
11431              FD->getParamDecl(FormatIdx)->getType()->isObjCObjectPointerType())
11432            fmt = "NSString";
11433          FD->addAttr(FormatAttr::CreateImplicit(Context,
11434                                                 &Context.Idents.get(fmt),
11435                                                 FormatIdx+1,
11436                                                 HasVAListArg ? 0 : FormatIdx+2,
11437                                                 FD->getLocation()));
11438        }
11439      }
11440      if (Context.BuiltinInfo.isScanfLike(BuiltinID, FormatIdx,
11441                                               HasVAListArg)) {
11442       if (!FD->hasAttr<FormatAttr>())
11443         FD->addAttr(FormatAttr::CreateImplicit(Context,
11444                                                &Context.Idents.get("scanf"),
11445                                                FormatIdx+1,
11446                                                HasVAListArg ? 0 : FormatIdx+2,
11447                                                FD->getLocation()));
11448      }
11449  
11450      // Mark const if we don't care about errno and that is the only
11451      // thing preventing the function from being const. This allows
11452      // IRgen to use LLVM intrinsics for such functions.
11453      if (!getLangOpts().MathErrno &&
11454          Context.BuiltinInfo.isConstWithoutErrno(BuiltinID)) {
11455        if (!FD->hasAttr<ConstAttr>())
11456          FD->addAttr(ConstAttr::CreateImplicit(Context, FD->getLocation()));
11457      }
11458  
11459      if (Context.BuiltinInfo.isReturnsTwice(BuiltinID) &&
11460          !FD->hasAttr<ReturnsTwiceAttr>())
11461        FD->addAttr(ReturnsTwiceAttr::CreateImplicit(Context,
11462                                           FD->getLocation()));
11463      if (Context.BuiltinInfo.isNoThrow(BuiltinID) && !FD->hasAttr<NoThrowAttr>())
11464        FD->addAttr(NoThrowAttr::CreateImplicit(Context, FD->getLocation()));
11465      if (Context.BuiltinInfo.isConst(BuiltinID) && !FD->hasAttr<ConstAttr>())
11466        FD->addAttr(ConstAttr::CreateImplicit(Context, FD->getLocation()));
11467      if (getLangOpts().CUDA && getLangOpts().CUDATargetOverloads &&
11468          Context.BuiltinInfo.isTSBuiltin(BuiltinID) &&
11469          !FD->hasAttr<CUDADeviceAttr>() && !FD->hasAttr<CUDAHostAttr>()) {
11470        // Assign appropriate attribute depending on CUDA compilation
11471        // mode and the target builtin belongs to. E.g. during host
11472        // compilation, aux builtins are __device__, the rest are __host__.
11473        if (getLangOpts().CUDAIsDevice !=
11474            Context.BuiltinInfo.isAuxBuiltinID(BuiltinID))
11475          FD->addAttr(CUDADeviceAttr::CreateImplicit(Context, FD->getLocation()));
11476        else
11477          FD->addAttr(CUDAHostAttr::CreateImplicit(Context, FD->getLocation()));
11478      }
11479    }
11480  
11481    IdentifierInfo *Name = FD->getIdentifier();
11482    if (!Name)
11483      return;
11484    if ((!getLangOpts().CPlusPlus &&
11485         FD->getDeclContext()->isTranslationUnit()) ||
11486        (isa<LinkageSpecDecl>(FD->getDeclContext()) &&
11487         cast<LinkageSpecDecl>(FD->getDeclContext())->getLanguage() ==
11488         LinkageSpecDecl::lang_c)) {
11489      // Okay: this could be a libc/libm/Objective-C function we know
11490      // about.
11491    } else
11492      return;
11493  
11494    if (Name->isStr("asprintf") || Name->isStr("vasprintf")) {
11495      // FIXME: asprintf and vasprintf aren't C99 functions. Should they be
11496      // target-specific builtins, perhaps?
11497      if (!FD->hasAttr<FormatAttr>())
11498        FD->addAttr(FormatAttr::CreateImplicit(Context,
11499                                               &Context.Idents.get("printf"), 2,
11500                                               Name->isStr("vasprintf") ? 0 : 3,
11501                                               FD->getLocation()));
11502    }
11503  
11504    if (Name->isStr("__CFStringMakeConstantString")) {
11505      // We already have a __builtin___CFStringMakeConstantString,
11506      // but builds that use -fno-constant-cfstrings don't go through that.
11507      if (!FD->hasAttr<FormatArgAttr>())
11508        FD->addAttr(FormatArgAttr::CreateImplicit(Context, 1,
11509                                                  FD->getLocation()));
11510    }
11511  }
11512  
ParseTypedefDecl(Scope * S,Declarator & D,QualType T,TypeSourceInfo * TInfo)11513  TypedefDecl *Sema::ParseTypedefDecl(Scope *S, Declarator &D, QualType T,
11514                                      TypeSourceInfo *TInfo) {
11515    assert(D.getIdentifier() && "Wrong callback for declspec without declarator");
11516    assert(!T.isNull() && "GetTypeForDeclarator() returned null type");
11517  
11518    if (!TInfo) {
11519      assert(D.isInvalidType() && "no declarator info for valid type");
11520      TInfo = Context.getTrivialTypeSourceInfo(T);
11521    }
11522  
11523    // Scope manipulation handled by caller.
11524    TypedefDecl *NewTD = TypedefDecl::Create(Context, CurContext,
11525                                             D.getLocStart(),
11526                                             D.getIdentifierLoc(),
11527                                             D.getIdentifier(),
11528                                             TInfo);
11529  
11530    // Bail out immediately if we have an invalid declaration.
11531    if (D.isInvalidType()) {
11532      NewTD->setInvalidDecl();
11533      return NewTD;
11534    }
11535  
11536    if (D.getDeclSpec().isModulePrivateSpecified()) {
11537      if (CurContext->isFunctionOrMethod())
11538        Diag(NewTD->getLocation(), diag::err_module_private_local)
11539          << 2 << NewTD->getDeclName()
11540          << SourceRange(D.getDeclSpec().getModulePrivateSpecLoc())
11541          << FixItHint::CreateRemoval(D.getDeclSpec().getModulePrivateSpecLoc());
11542      else
11543        NewTD->setModulePrivate();
11544    }
11545  
11546    // C++ [dcl.typedef]p8:
11547    //   If the typedef declaration defines an unnamed class (or
11548    //   enum), the first typedef-name declared by the declaration
11549    //   to be that class type (or enum type) is used to denote the
11550    //   class type (or enum type) for linkage purposes only.
11551    // We need to check whether the type was declared in the declaration.
11552    switch (D.getDeclSpec().getTypeSpecType()) {
11553    case TST_enum:
11554    case TST_struct:
11555    case TST_interface:
11556    case TST_union:
11557    case TST_class: {
11558      TagDecl *tagFromDeclSpec = cast<TagDecl>(D.getDeclSpec().getRepAsDecl());
11559      setTagNameForLinkagePurposes(tagFromDeclSpec, NewTD);
11560      break;
11561    }
11562  
11563    default:
11564      break;
11565    }
11566  
11567    return NewTD;
11568  }
11569  
11570  
11571  /// \brief Check that this is a valid underlying type for an enum declaration.
CheckEnumUnderlyingType(TypeSourceInfo * TI)11572  bool Sema::CheckEnumUnderlyingType(TypeSourceInfo *TI) {
11573    SourceLocation UnderlyingLoc = TI->getTypeLoc().getBeginLoc();
11574    QualType T = TI->getType();
11575  
11576    if (T->isDependentType())
11577      return false;
11578  
11579    if (const BuiltinType *BT = T->getAs<BuiltinType>())
11580      if (BT->isInteger())
11581        return false;
11582  
11583    Diag(UnderlyingLoc, diag::err_enum_invalid_underlying) << T;
11584    return true;
11585  }
11586  
11587  /// Check whether this is a valid redeclaration of a previous enumeration.
11588  /// \return true if the redeclaration was invalid.
CheckEnumRedeclaration(SourceLocation EnumLoc,bool IsScoped,QualType EnumUnderlyingTy,bool EnumUnderlyingIsImplicit,const EnumDecl * Prev)11589  bool Sema::CheckEnumRedeclaration(
11590      SourceLocation EnumLoc, bool IsScoped, QualType EnumUnderlyingTy,
11591      bool EnumUnderlyingIsImplicit, const EnumDecl *Prev) {
11592    bool IsFixed = !EnumUnderlyingTy.isNull();
11593  
11594    if (IsScoped != Prev->isScoped()) {
11595      Diag(EnumLoc, diag::err_enum_redeclare_scoped_mismatch)
11596        << Prev->isScoped();
11597      Diag(Prev->getLocation(), diag::note_previous_declaration);
11598      return true;
11599    }
11600  
11601    if (IsFixed && Prev->isFixed()) {
11602      if (!EnumUnderlyingTy->isDependentType() &&
11603          !Prev->getIntegerType()->isDependentType() &&
11604          !Context.hasSameUnqualifiedType(EnumUnderlyingTy,
11605                                          Prev->getIntegerType())) {
11606        // TODO: Highlight the underlying type of the redeclaration.
11607        Diag(EnumLoc, diag::err_enum_redeclare_type_mismatch)
11608          << EnumUnderlyingTy << Prev->getIntegerType();
11609        Diag(Prev->getLocation(), diag::note_previous_declaration)
11610            << Prev->getIntegerTypeRange();
11611        return true;
11612      }
11613    } else if (IsFixed && !Prev->isFixed() && EnumUnderlyingIsImplicit) {
11614      ;
11615    } else if (!IsFixed && Prev->isFixed() && !Prev->getIntegerTypeSourceInfo()) {
11616      ;
11617    } else if (IsFixed != Prev->isFixed()) {
11618      Diag(EnumLoc, diag::err_enum_redeclare_fixed_mismatch)
11619        << Prev->isFixed();
11620      Diag(Prev->getLocation(), diag::note_previous_declaration);
11621      return true;
11622    }
11623  
11624    return false;
11625  }
11626  
11627  /// \brief Get diagnostic %select index for tag kind for
11628  /// redeclaration diagnostic message.
11629  /// WARNING: Indexes apply to particular diagnostics only!
11630  ///
11631  /// \returns diagnostic %select index.
getRedeclDiagFromTagKind(TagTypeKind Tag)11632  static unsigned getRedeclDiagFromTagKind(TagTypeKind Tag) {
11633    switch (Tag) {
11634    case TTK_Struct: return 0;
11635    case TTK_Interface: return 1;
11636    case TTK_Class:  return 2;
11637    default: llvm_unreachable("Invalid tag kind for redecl diagnostic!");
11638    }
11639  }
11640  
11641  /// \brief Determine if tag kind is a class-key compatible with
11642  /// class for redeclaration (class, struct, or __interface).
11643  ///
11644  /// \returns true iff the tag kind is compatible.
isClassCompatTagKind(TagTypeKind Tag)11645  static bool isClassCompatTagKind(TagTypeKind Tag)
11646  {
11647    return Tag == TTK_Struct || Tag == TTK_Class || Tag == TTK_Interface;
11648  }
11649  
11650  /// \brief Determine whether a tag with a given kind is acceptable
11651  /// as a redeclaration of the given tag declaration.
11652  ///
11653  /// \returns true if the new tag kind is acceptable, false otherwise.
isAcceptableTagRedeclaration(const TagDecl * Previous,TagTypeKind NewTag,bool isDefinition,SourceLocation NewTagLoc,const IdentifierInfo * Name)11654  bool Sema::isAcceptableTagRedeclaration(const TagDecl *Previous,
11655                                          TagTypeKind NewTag, bool isDefinition,
11656                                          SourceLocation NewTagLoc,
11657                                          const IdentifierInfo *Name) {
11658    // C++ [dcl.type.elab]p3:
11659    //   The class-key or enum keyword present in the
11660    //   elaborated-type-specifier shall agree in kind with the
11661    //   declaration to which the name in the elaborated-type-specifier
11662    //   refers. This rule also applies to the form of
11663    //   elaborated-type-specifier that declares a class-name or
11664    //   friend class since it can be construed as referring to the
11665    //   definition of the class. Thus, in any
11666    //   elaborated-type-specifier, the enum keyword shall be used to
11667    //   refer to an enumeration (7.2), the union class-key shall be
11668    //   used to refer to a union (clause 9), and either the class or
11669    //   struct class-key shall be used to refer to a class (clause 9)
11670    //   declared using the class or struct class-key.
11671    TagTypeKind OldTag = Previous->getTagKind();
11672    if (!isDefinition || !isClassCompatTagKind(NewTag))
11673      if (OldTag == NewTag)
11674        return true;
11675  
11676    if (isClassCompatTagKind(OldTag) && isClassCompatTagKind(NewTag)) {
11677      // Warn about the struct/class tag mismatch.
11678      bool isTemplate = false;
11679      if (const CXXRecordDecl *Record = dyn_cast<CXXRecordDecl>(Previous))
11680        isTemplate = Record->getDescribedClassTemplate();
11681  
11682      if (!ActiveTemplateInstantiations.empty()) {
11683        // In a template instantiation, do not offer fix-its for tag mismatches
11684        // since they usually mess up the template instead of fixing the problem.
11685        Diag(NewTagLoc, diag::warn_struct_class_tag_mismatch)
11686          << getRedeclDiagFromTagKind(NewTag) << isTemplate << Name
11687          << getRedeclDiagFromTagKind(OldTag);
11688        return true;
11689      }
11690  
11691      if (isDefinition) {
11692        // On definitions, check previous tags and issue a fix-it for each
11693        // one that doesn't match the current tag.
11694        if (Previous->getDefinition()) {
11695          // Don't suggest fix-its for redefinitions.
11696          return true;
11697        }
11698  
11699        bool previousMismatch = false;
11700        for (auto I : Previous->redecls()) {
11701          if (I->getTagKind() != NewTag) {
11702            if (!previousMismatch) {
11703              previousMismatch = true;
11704              Diag(NewTagLoc, diag::warn_struct_class_previous_tag_mismatch)
11705                << getRedeclDiagFromTagKind(NewTag) << isTemplate << Name
11706                << getRedeclDiagFromTagKind(I->getTagKind());
11707            }
11708            Diag(I->getInnerLocStart(), diag::note_struct_class_suggestion)
11709              << getRedeclDiagFromTagKind(NewTag)
11710              << FixItHint::CreateReplacement(I->getInnerLocStart(),
11711                   TypeWithKeyword::getTagTypeKindName(NewTag));
11712          }
11713        }
11714        return true;
11715      }
11716  
11717      // Check for a previous definition.  If current tag and definition
11718      // are same type, do nothing.  If no definition, but disagree with
11719      // with previous tag type, give a warning, but no fix-it.
11720      const TagDecl *Redecl = Previous->getDefinition() ?
11721                              Previous->getDefinition() : Previous;
11722      if (Redecl->getTagKind() == NewTag) {
11723        return true;
11724      }
11725  
11726      Diag(NewTagLoc, diag::warn_struct_class_tag_mismatch)
11727        << getRedeclDiagFromTagKind(NewTag) << isTemplate << Name
11728        << getRedeclDiagFromTagKind(OldTag);
11729      Diag(Redecl->getLocation(), diag::note_previous_use);
11730  
11731      // If there is a previous definition, suggest a fix-it.
11732      if (Previous->getDefinition()) {
11733          Diag(NewTagLoc, diag::note_struct_class_suggestion)
11734            << getRedeclDiagFromTagKind(Redecl->getTagKind())
11735            << FixItHint::CreateReplacement(SourceRange(NewTagLoc),
11736                 TypeWithKeyword::getTagTypeKindName(Redecl->getTagKind()));
11737      }
11738  
11739      return true;
11740    }
11741    return false;
11742  }
11743  
11744  /// Add a minimal nested name specifier fixit hint to allow lookup of a tag name
11745  /// from an outer enclosing namespace or file scope inside a friend declaration.
11746  /// This should provide the commented out code in the following snippet:
11747  ///   namespace N {
11748  ///     struct X;
11749  ///     namespace M {
11750  ///       struct Y { friend struct /*N::*/ X; };
11751  ///     }
11752  ///   }
createFriendTagNNSFixIt(Sema & SemaRef,NamedDecl * ND,Scope * S,SourceLocation NameLoc)11753  static FixItHint createFriendTagNNSFixIt(Sema &SemaRef, NamedDecl *ND, Scope *S,
11754                                           SourceLocation NameLoc) {
11755    // While the decl is in a namespace, do repeated lookup of that name and see
11756    // if we get the same namespace back.  If we do not, continue until
11757    // translation unit scope, at which point we have a fully qualified NNS.
11758    SmallVector<IdentifierInfo *, 4> Namespaces;
11759    DeclContext *DC = ND->getDeclContext()->getRedeclContext();
11760    for (; !DC->isTranslationUnit(); DC = DC->getParent()) {
11761      // This tag should be declared in a namespace, which can only be enclosed by
11762      // other namespaces.  Bail if there's an anonymous namespace in the chain.
11763      NamespaceDecl *Namespace = dyn_cast<NamespaceDecl>(DC);
11764      if (!Namespace || Namespace->isAnonymousNamespace())
11765        return FixItHint();
11766      IdentifierInfo *II = Namespace->getIdentifier();
11767      Namespaces.push_back(II);
11768      NamedDecl *Lookup = SemaRef.LookupSingleName(
11769          S, II, NameLoc, Sema::LookupNestedNameSpecifierName);
11770      if (Lookup == Namespace)
11771        break;
11772    }
11773  
11774    // Once we have all the namespaces, reverse them to go outermost first, and
11775    // build an NNS.
11776    SmallString<64> Insertion;
11777    llvm::raw_svector_ostream OS(Insertion);
11778    if (DC->isTranslationUnit())
11779      OS << "::";
11780    std::reverse(Namespaces.begin(), Namespaces.end());
11781    for (auto *II : Namespaces)
11782      OS << II->getName() << "::";
11783    return FixItHint::CreateInsertion(NameLoc, Insertion);
11784  }
11785  
11786  /// \brief Determine whether a tag originally declared in context \p OldDC can
11787  /// be redeclared with an unqualfied name in \p NewDC (assuming name lookup
11788  /// found a declaration in \p OldDC as a previous decl, perhaps through a
11789  /// using-declaration).
isAcceptableTagRedeclContext(Sema & S,DeclContext * OldDC,DeclContext * NewDC)11790  static bool isAcceptableTagRedeclContext(Sema &S, DeclContext *OldDC,
11791                                           DeclContext *NewDC) {
11792    OldDC = OldDC->getRedeclContext();
11793    NewDC = NewDC->getRedeclContext();
11794  
11795    if (OldDC->Equals(NewDC))
11796      return true;
11797  
11798    // In MSVC mode, we allow a redeclaration if the contexts are related (either
11799    // encloses the other).
11800    if (S.getLangOpts().MSVCCompat &&
11801        (OldDC->Encloses(NewDC) || NewDC->Encloses(OldDC)))
11802      return true;
11803  
11804    return false;
11805  }
11806  
11807  /// \brief This is invoked when we see 'struct foo' or 'struct {'.  In the
11808  /// former case, Name will be non-null.  In the later case, Name will be null.
11809  /// TagSpec indicates what kind of tag this is. TUK indicates whether this is a
11810  /// reference/declaration/definition of a tag.
11811  ///
11812  /// \param IsTypeSpecifier \c true if this is a type-specifier (or
11813  /// trailing-type-specifier) other than one in an alias-declaration.
11814  ///
11815  /// \param SkipBody If non-null, will be set to indicate if the caller should
11816  /// skip the definition of this tag and treat it as if it were a declaration.
ActOnTag(Scope * S,unsigned TagSpec,TagUseKind TUK,SourceLocation KWLoc,CXXScopeSpec & SS,IdentifierInfo * Name,SourceLocation NameLoc,AttributeList * Attr,AccessSpecifier AS,SourceLocation ModulePrivateLoc,MultiTemplateParamsArg TemplateParameterLists,bool & OwnedDecl,bool & IsDependent,SourceLocation ScopedEnumKWLoc,bool ScopedEnumUsesClassTag,TypeResult UnderlyingType,bool IsTypeSpecifier,SkipBodyInfo * SkipBody)11817  Decl *Sema::ActOnTag(Scope *S, unsigned TagSpec, TagUseKind TUK,
11818                       SourceLocation KWLoc, CXXScopeSpec &SS,
11819                       IdentifierInfo *Name, SourceLocation NameLoc,
11820                       AttributeList *Attr, AccessSpecifier AS,
11821                       SourceLocation ModulePrivateLoc,
11822                       MultiTemplateParamsArg TemplateParameterLists,
11823                       bool &OwnedDecl, bool &IsDependent,
11824                       SourceLocation ScopedEnumKWLoc,
11825                       bool ScopedEnumUsesClassTag,
11826                       TypeResult UnderlyingType,
11827                       bool IsTypeSpecifier, SkipBodyInfo *SkipBody) {
11828    // If this is not a definition, it must have a name.
11829    IdentifierInfo *OrigName = Name;
11830    assert((Name != nullptr || TUK == TUK_Definition) &&
11831           "Nameless record must be a definition!");
11832    assert(TemplateParameterLists.size() == 0 || TUK != TUK_Reference);
11833  
11834    OwnedDecl = false;
11835    TagTypeKind Kind = TypeWithKeyword::getTagTypeKindForTypeSpec(TagSpec);
11836    bool ScopedEnum = ScopedEnumKWLoc.isValid();
11837  
11838    // FIXME: Check explicit specializations more carefully.
11839    bool isExplicitSpecialization = false;
11840    bool Invalid = false;
11841  
11842    // We only need to do this matching if we have template parameters
11843    // or a scope specifier, which also conveniently avoids this work
11844    // for non-C++ cases.
11845    if (TemplateParameterLists.size() > 0 ||
11846        (SS.isNotEmpty() && TUK != TUK_Reference)) {
11847      if (TemplateParameterList *TemplateParams =
11848              MatchTemplateParametersToScopeSpecifier(
11849                  KWLoc, NameLoc, SS, nullptr, TemplateParameterLists,
11850                  TUK == TUK_Friend, isExplicitSpecialization, Invalid)) {
11851        if (Kind == TTK_Enum) {
11852          Diag(KWLoc, diag::err_enum_template);
11853          return nullptr;
11854        }
11855  
11856        if (TemplateParams->size() > 0) {
11857          // This is a declaration or definition of a class template (which may
11858          // be a member of another template).
11859  
11860          if (Invalid)
11861            return nullptr;
11862  
11863          OwnedDecl = false;
11864          DeclResult Result = CheckClassTemplate(S, TagSpec, TUK, KWLoc,
11865                                                 SS, Name, NameLoc, Attr,
11866                                                 TemplateParams, AS,
11867                                                 ModulePrivateLoc,
11868                                                 /*FriendLoc*/SourceLocation(),
11869                                                 TemplateParameterLists.size()-1,
11870                                                 TemplateParameterLists.data(),
11871                                                 SkipBody);
11872          return Result.get();
11873        } else {
11874          // The "template<>" header is extraneous.
11875          Diag(TemplateParams->getTemplateLoc(), diag::err_template_tag_noparams)
11876            << TypeWithKeyword::getTagTypeKindName(Kind) << Name;
11877          isExplicitSpecialization = true;
11878        }
11879      }
11880    }
11881  
11882    // Figure out the underlying type if this a enum declaration. We need to do
11883    // this early, because it's needed to detect if this is an incompatible
11884    // redeclaration.
11885    llvm::PointerUnion<const Type*, TypeSourceInfo*> EnumUnderlying;
11886    bool EnumUnderlyingIsImplicit = false;
11887  
11888    if (Kind == TTK_Enum) {
11889      if (UnderlyingType.isInvalid() || (!UnderlyingType.get() && ScopedEnum))
11890        // No underlying type explicitly specified, or we failed to parse the
11891        // type, default to int.
11892        EnumUnderlying = Context.IntTy.getTypePtr();
11893      else if (UnderlyingType.get()) {
11894        // C++0x 7.2p2: The type-specifier-seq of an enum-base shall name an
11895        // integral type; any cv-qualification is ignored.
11896        TypeSourceInfo *TI = nullptr;
11897        GetTypeFromParser(UnderlyingType.get(), &TI);
11898        EnumUnderlying = TI;
11899  
11900        if (CheckEnumUnderlyingType(TI))
11901          // Recover by falling back to int.
11902          EnumUnderlying = Context.IntTy.getTypePtr();
11903  
11904        if (DiagnoseUnexpandedParameterPack(TI->getTypeLoc().getBeginLoc(), TI,
11905                                            UPPC_FixedUnderlyingType))
11906          EnumUnderlying = Context.IntTy.getTypePtr();
11907  
11908      } else if (Context.getTargetInfo().getCXXABI().isMicrosoft()) {
11909        if (getLangOpts().MSVCCompat || TUK == TUK_Definition) {
11910          // Microsoft enums are always of int type.
11911          EnumUnderlying = Context.IntTy.getTypePtr();
11912          EnumUnderlyingIsImplicit = true;
11913        }
11914      }
11915    }
11916  
11917    DeclContext *SearchDC = CurContext;
11918    DeclContext *DC = CurContext;
11919    bool isStdBadAlloc = false;
11920  
11921    RedeclarationKind Redecl = ForRedeclaration;
11922    if (TUK == TUK_Friend || TUK == TUK_Reference)
11923      Redecl = NotForRedeclaration;
11924  
11925    LookupResult Previous(*this, Name, NameLoc, LookupTagName, Redecl);
11926    if (Name && SS.isNotEmpty()) {
11927      // We have a nested-name tag ('struct foo::bar').
11928  
11929      // Check for invalid 'foo::'.
11930      if (SS.isInvalid()) {
11931        Name = nullptr;
11932        goto CreateNewDecl;
11933      }
11934  
11935      // If this is a friend or a reference to a class in a dependent
11936      // context, don't try to make a decl for it.
11937      if (TUK == TUK_Friend || TUK == TUK_Reference) {
11938        DC = computeDeclContext(SS, false);
11939        if (!DC) {
11940          IsDependent = true;
11941          return nullptr;
11942        }
11943      } else {
11944        DC = computeDeclContext(SS, true);
11945        if (!DC) {
11946          Diag(SS.getRange().getBegin(), diag::err_dependent_nested_name_spec)
11947            << SS.getRange();
11948          return nullptr;
11949        }
11950      }
11951  
11952      if (RequireCompleteDeclContext(SS, DC))
11953        return nullptr;
11954  
11955      SearchDC = DC;
11956      // Look-up name inside 'foo::'.
11957      LookupQualifiedName(Previous, DC);
11958  
11959      if (Previous.isAmbiguous())
11960        return nullptr;
11961  
11962      if (Previous.empty()) {
11963        // Name lookup did not find anything. However, if the
11964        // nested-name-specifier refers to the current instantiation,
11965        // and that current instantiation has any dependent base
11966        // classes, we might find something at instantiation time: treat
11967        // this as a dependent elaborated-type-specifier.
11968        // But this only makes any sense for reference-like lookups.
11969        if (Previous.wasNotFoundInCurrentInstantiation() &&
11970            (TUK == TUK_Reference || TUK == TUK_Friend)) {
11971          IsDependent = true;
11972          return nullptr;
11973        }
11974  
11975        // A tag 'foo::bar' must already exist.
11976        Diag(NameLoc, diag::err_not_tag_in_scope)
11977          << Kind << Name << DC << SS.getRange();
11978        Name = nullptr;
11979        Invalid = true;
11980        goto CreateNewDecl;
11981      }
11982    } else if (Name) {
11983      // C++14 [class.mem]p14:
11984      //   If T is the name of a class, then each of the following shall have a
11985      //   name different from T:
11986      //    -- every member of class T that is itself a type
11987      if (TUK != TUK_Reference && TUK != TUK_Friend &&
11988          DiagnoseClassNameShadow(SearchDC, DeclarationNameInfo(Name, NameLoc)))
11989        return nullptr;
11990  
11991      // If this is a named struct, check to see if there was a previous forward
11992      // declaration or definition.
11993      // FIXME: We're looking into outer scopes here, even when we
11994      // shouldn't be. Doing so can result in ambiguities that we
11995      // shouldn't be diagnosing.
11996      LookupName(Previous, S);
11997  
11998      // When declaring or defining a tag, ignore ambiguities introduced
11999      // by types using'ed into this scope.
12000      if (Previous.isAmbiguous() &&
12001          (TUK == TUK_Definition || TUK == TUK_Declaration)) {
12002        LookupResult::Filter F = Previous.makeFilter();
12003        while (F.hasNext()) {
12004          NamedDecl *ND = F.next();
12005          if (ND->getDeclContext()->getRedeclContext() != SearchDC)
12006            F.erase();
12007        }
12008        F.done();
12009      }
12010  
12011      // C++11 [namespace.memdef]p3:
12012      //   If the name in a friend declaration is neither qualified nor
12013      //   a template-id and the declaration is a function or an
12014      //   elaborated-type-specifier, the lookup to determine whether
12015      //   the entity has been previously declared shall not consider
12016      //   any scopes outside the innermost enclosing namespace.
12017      //
12018      // MSVC doesn't implement the above rule for types, so a friend tag
12019      // declaration may be a redeclaration of a type declared in an enclosing
12020      // scope.  They do implement this rule for friend functions.
12021      //
12022      // Does it matter that this should be by scope instead of by
12023      // semantic context?
12024      if (!Previous.empty() && TUK == TUK_Friend) {
12025        DeclContext *EnclosingNS = SearchDC->getEnclosingNamespaceContext();
12026        LookupResult::Filter F = Previous.makeFilter();
12027        bool FriendSawTagOutsideEnclosingNamespace = false;
12028        while (F.hasNext()) {
12029          NamedDecl *ND = F.next();
12030          DeclContext *DC = ND->getDeclContext()->getRedeclContext();
12031          if (DC->isFileContext() &&
12032              !EnclosingNS->Encloses(ND->getDeclContext())) {
12033            if (getLangOpts().MSVCCompat)
12034              FriendSawTagOutsideEnclosingNamespace = true;
12035            else
12036              F.erase();
12037          }
12038        }
12039        F.done();
12040  
12041        // Diagnose this MSVC extension in the easy case where lookup would have
12042        // unambiguously found something outside the enclosing namespace.
12043        if (Previous.isSingleResult() && FriendSawTagOutsideEnclosingNamespace) {
12044          NamedDecl *ND = Previous.getFoundDecl();
12045          Diag(NameLoc, diag::ext_friend_tag_redecl_outside_namespace)
12046              << createFriendTagNNSFixIt(*this, ND, S, NameLoc);
12047        }
12048      }
12049  
12050      // Note:  there used to be some attempt at recovery here.
12051      if (Previous.isAmbiguous())
12052        return nullptr;
12053  
12054      if (!getLangOpts().CPlusPlus && TUK != TUK_Reference) {
12055        // FIXME: This makes sure that we ignore the contexts associated
12056        // with C structs, unions, and enums when looking for a matching
12057        // tag declaration or definition. See the similar lookup tweak
12058        // in Sema::LookupName; is there a better way to deal with this?
12059        while (isa<RecordDecl>(SearchDC) || isa<EnumDecl>(SearchDC))
12060          SearchDC = SearchDC->getParent();
12061      }
12062    }
12063  
12064    if (Previous.isSingleResult() &&
12065        Previous.getFoundDecl()->isTemplateParameter()) {
12066      // Maybe we will complain about the shadowed template parameter.
12067      DiagnoseTemplateParameterShadow(NameLoc, Previous.getFoundDecl());
12068      // Just pretend that we didn't see the previous declaration.
12069      Previous.clear();
12070    }
12071  
12072    if (getLangOpts().CPlusPlus && Name && DC && StdNamespace &&
12073        DC->Equals(getStdNamespace()) && Name->isStr("bad_alloc")) {
12074      // This is a declaration of or a reference to "std::bad_alloc".
12075      isStdBadAlloc = true;
12076  
12077      if (Previous.empty() && StdBadAlloc) {
12078        // std::bad_alloc has been implicitly declared (but made invisible to
12079        // name lookup). Fill in this implicit declaration as the previous
12080        // declaration, so that the declarations get chained appropriately.
12081        Previous.addDecl(getStdBadAlloc());
12082      }
12083    }
12084  
12085    // If we didn't find a previous declaration, and this is a reference
12086    // (or friend reference), move to the correct scope.  In C++, we
12087    // also need to do a redeclaration lookup there, just in case
12088    // there's a shadow friend decl.
12089    if (Name && Previous.empty() &&
12090        (TUK == TUK_Reference || TUK == TUK_Friend)) {
12091      if (Invalid) goto CreateNewDecl;
12092      assert(SS.isEmpty());
12093  
12094      if (TUK == TUK_Reference) {
12095        // C++ [basic.scope.pdecl]p5:
12096        //   -- for an elaborated-type-specifier of the form
12097        //
12098        //          class-key identifier
12099        //
12100        //      if the elaborated-type-specifier is used in the
12101        //      decl-specifier-seq or parameter-declaration-clause of a
12102        //      function defined in namespace scope, the identifier is
12103        //      declared as a class-name in the namespace that contains
12104        //      the declaration; otherwise, except as a friend
12105        //      declaration, the identifier is declared in the smallest
12106        //      non-class, non-function-prototype scope that contains the
12107        //      declaration.
12108        //
12109        // C99 6.7.2.3p8 has a similar (but not identical!) provision for
12110        // C structs and unions.
12111        //
12112        // It is an error in C++ to declare (rather than define) an enum
12113        // type, including via an elaborated type specifier.  We'll
12114        // diagnose that later; for now, declare the enum in the same
12115        // scope as we would have picked for any other tag type.
12116        //
12117        // GNU C also supports this behavior as part of its incomplete
12118        // enum types extension, while GNU C++ does not.
12119        //
12120        // Find the context where we'll be declaring the tag.
12121        // FIXME: We would like to maintain the current DeclContext as the
12122        // lexical context,
12123        while (!SearchDC->isFileContext() && !SearchDC->isFunctionOrMethod())
12124          SearchDC = SearchDC->getParent();
12125  
12126        // Find the scope where we'll be declaring the tag.
12127        while (S->isClassScope() ||
12128               (getLangOpts().CPlusPlus &&
12129                S->isFunctionPrototypeScope()) ||
12130               ((S->getFlags() & Scope::DeclScope) == 0) ||
12131               (S->getEntity() && S->getEntity()->isTransparentContext()))
12132          S = S->getParent();
12133      } else {
12134        assert(TUK == TUK_Friend);
12135        // C++ [namespace.memdef]p3:
12136        //   If a friend declaration in a non-local class first declares a
12137        //   class or function, the friend class or function is a member of
12138        //   the innermost enclosing namespace.
12139        SearchDC = SearchDC->getEnclosingNamespaceContext();
12140      }
12141  
12142      // In C++, we need to do a redeclaration lookup to properly
12143      // diagnose some problems.
12144      // FIXME: redeclaration lookup is also used (with and without C++) to find a
12145      // hidden declaration so that we don't get ambiguity errors when using a
12146      // type declared by an elaborated-type-specifier.  In C that is not correct
12147      // and we should instead merge compatible types found by lookup.
12148      if (getLangOpts().CPlusPlus) {
12149        Previous.setRedeclarationKind(ForRedeclaration);
12150        LookupQualifiedName(Previous, SearchDC);
12151      } else {
12152        Previous.setRedeclarationKind(ForRedeclaration);
12153        LookupName(Previous, S);
12154      }
12155    }
12156  
12157    // If we have a known previous declaration to use, then use it.
12158    if (Previous.empty() && SkipBody && SkipBody->Previous)
12159      Previous.addDecl(SkipBody->Previous);
12160  
12161    if (!Previous.empty()) {
12162      NamedDecl *PrevDecl = Previous.getFoundDecl();
12163      NamedDecl *DirectPrevDecl = Previous.getRepresentativeDecl();
12164  
12165      // It's okay to have a tag decl in the same scope as a typedef
12166      // which hides a tag decl in the same scope.  Finding this
12167      // insanity with a redeclaration lookup can only actually happen
12168      // in C++.
12169      //
12170      // This is also okay for elaborated-type-specifiers, which is
12171      // technically forbidden by the current standard but which is
12172      // okay according to the likely resolution of an open issue;
12173      // see http://www.open-std.org/jtc1/sc22/wg21/docs/cwg_active.html#407
12174      if (getLangOpts().CPlusPlus) {
12175        if (TypedefNameDecl *TD = dyn_cast<TypedefNameDecl>(PrevDecl)) {
12176          if (const TagType *TT = TD->getUnderlyingType()->getAs<TagType>()) {
12177            TagDecl *Tag = TT->getDecl();
12178            if (Tag->getDeclName() == Name &&
12179                Tag->getDeclContext()->getRedeclContext()
12180                            ->Equals(TD->getDeclContext()->getRedeclContext())) {
12181              PrevDecl = Tag;
12182              Previous.clear();
12183              Previous.addDecl(Tag);
12184              Previous.resolveKind();
12185            }
12186          }
12187        }
12188      }
12189  
12190      // If this is a redeclaration of a using shadow declaration, it must
12191      // declare a tag in the same context. In MSVC mode, we allow a
12192      // redefinition if either context is within the other.
12193      if (auto *Shadow = dyn_cast<UsingShadowDecl>(DirectPrevDecl)) {
12194        auto *OldTag = dyn_cast<TagDecl>(PrevDecl);
12195        if (SS.isEmpty() && TUK != TUK_Reference && TUK != TUK_Friend &&
12196            isDeclInScope(Shadow, SearchDC, S, isExplicitSpecialization) &&
12197            !(OldTag && isAcceptableTagRedeclContext(
12198                            *this, OldTag->getDeclContext(), SearchDC))) {
12199          Diag(KWLoc, diag::err_using_decl_conflict_reverse);
12200          Diag(Shadow->getTargetDecl()->getLocation(),
12201               diag::note_using_decl_target);
12202          Diag(Shadow->getUsingDecl()->getLocation(), diag::note_using_decl)
12203              << 0;
12204          // Recover by ignoring the old declaration.
12205          Previous.clear();
12206          goto CreateNewDecl;
12207        }
12208      }
12209  
12210      if (TagDecl *PrevTagDecl = dyn_cast<TagDecl>(PrevDecl)) {
12211        // If this is a use of a previous tag, or if the tag is already declared
12212        // in the same scope (so that the definition/declaration completes or
12213        // rementions the tag), reuse the decl.
12214        if (TUK == TUK_Reference || TUK == TUK_Friend ||
12215            isDeclInScope(DirectPrevDecl, SearchDC, S,
12216                          SS.isNotEmpty() || isExplicitSpecialization)) {
12217          // Make sure that this wasn't declared as an enum and now used as a
12218          // struct or something similar.
12219          if (!isAcceptableTagRedeclaration(PrevTagDecl, Kind,
12220                                            TUK == TUK_Definition, KWLoc,
12221                                            Name)) {
12222            bool SafeToContinue
12223              = (PrevTagDecl->getTagKind() != TTK_Enum &&
12224                 Kind != TTK_Enum);
12225            if (SafeToContinue)
12226              Diag(KWLoc, diag::err_use_with_wrong_tag)
12227                << Name
12228                << FixItHint::CreateReplacement(SourceRange(KWLoc),
12229                                                PrevTagDecl->getKindName());
12230            else
12231              Diag(KWLoc, diag::err_use_with_wrong_tag) << Name;
12232            Diag(PrevTagDecl->getLocation(), diag::note_previous_use);
12233  
12234            if (SafeToContinue)
12235              Kind = PrevTagDecl->getTagKind();
12236            else {
12237              // Recover by making this an anonymous redefinition.
12238              Name = nullptr;
12239              Previous.clear();
12240              Invalid = true;
12241            }
12242          }
12243  
12244          if (Kind == TTK_Enum && PrevTagDecl->getTagKind() == TTK_Enum) {
12245            const EnumDecl *PrevEnum = cast<EnumDecl>(PrevTagDecl);
12246  
12247            // If this is an elaborated-type-specifier for a scoped enumeration,
12248            // the 'class' keyword is not necessary and not permitted.
12249            if (TUK == TUK_Reference || TUK == TUK_Friend) {
12250              if (ScopedEnum)
12251                Diag(ScopedEnumKWLoc, diag::err_enum_class_reference)
12252                  << PrevEnum->isScoped()
12253                  << FixItHint::CreateRemoval(ScopedEnumKWLoc);
12254              return PrevTagDecl;
12255            }
12256  
12257            QualType EnumUnderlyingTy;
12258            if (TypeSourceInfo *TI = EnumUnderlying.dyn_cast<TypeSourceInfo*>())
12259              EnumUnderlyingTy = TI->getType().getUnqualifiedType();
12260            else if (const Type *T = EnumUnderlying.dyn_cast<const Type*>())
12261              EnumUnderlyingTy = QualType(T, 0);
12262  
12263            // All conflicts with previous declarations are recovered by
12264            // returning the previous declaration, unless this is a definition,
12265            // in which case we want the caller to bail out.
12266            if (CheckEnumRedeclaration(NameLoc.isValid() ? NameLoc : KWLoc,
12267                                       ScopedEnum, EnumUnderlyingTy,
12268                                       EnumUnderlyingIsImplicit, PrevEnum))
12269              return TUK == TUK_Declaration ? PrevTagDecl : nullptr;
12270          }
12271  
12272          // C++11 [class.mem]p1:
12273          //   A member shall not be declared twice in the member-specification,
12274          //   except that a nested class or member class template can be declared
12275          //   and then later defined.
12276          if (TUK == TUK_Declaration && PrevDecl->isCXXClassMember() &&
12277              S->isDeclScope(PrevDecl)) {
12278            Diag(NameLoc, diag::ext_member_redeclared);
12279            Diag(PrevTagDecl->getLocation(), diag::note_previous_declaration);
12280          }
12281  
12282          if (!Invalid) {
12283            // If this is a use, just return the declaration we found, unless
12284            // we have attributes.
12285  
12286            // FIXME: In the future, return a variant or some other clue
12287            // for the consumer of this Decl to know it doesn't own it.
12288            // For our current ASTs this shouldn't be a problem, but will
12289            // need to be changed with DeclGroups.
12290            if (!Attr &&
12291                ((TUK == TUK_Reference &&
12292                  (!PrevTagDecl->getFriendObjectKind() || getLangOpts().MicrosoftExt))
12293                 || TUK == TUK_Friend))
12294              return PrevTagDecl;
12295  
12296            // Diagnose attempts to redefine a tag.
12297            if (TUK == TUK_Definition) {
12298              if (NamedDecl *Def = PrevTagDecl->getDefinition()) {
12299                // If we're defining a specialization and the previous definition
12300                // is from an implicit instantiation, don't emit an error
12301                // here; we'll catch this in the general case below.
12302                bool IsExplicitSpecializationAfterInstantiation = false;
12303                if (isExplicitSpecialization) {
12304                  if (CXXRecordDecl *RD = dyn_cast<CXXRecordDecl>(Def))
12305                    IsExplicitSpecializationAfterInstantiation =
12306                      RD->getTemplateSpecializationKind() !=
12307                      TSK_ExplicitSpecialization;
12308                  else if (EnumDecl *ED = dyn_cast<EnumDecl>(Def))
12309                    IsExplicitSpecializationAfterInstantiation =
12310                      ED->getTemplateSpecializationKind() !=
12311                      TSK_ExplicitSpecialization;
12312                }
12313  
12314                NamedDecl *Hidden = nullptr;
12315                if (SkipBody && getLangOpts().CPlusPlus &&
12316                    !hasVisibleDefinition(Def, &Hidden)) {
12317                  // There is a definition of this tag, but it is not visible. We
12318                  // explicitly make use of C++'s one definition rule here, and
12319                  // assume that this definition is identical to the hidden one
12320                  // we already have. Make the existing definition visible and
12321                  // use it in place of this one.
12322                  SkipBody->ShouldSkip = true;
12323                  makeMergedDefinitionVisible(Hidden, KWLoc);
12324                  return Def;
12325                } else if (!IsExplicitSpecializationAfterInstantiation) {
12326                  // A redeclaration in function prototype scope in C isn't
12327                  // visible elsewhere, so merely issue a warning.
12328                  if (!getLangOpts().CPlusPlus && S->containedInPrototypeScope())
12329                    Diag(NameLoc, diag::warn_redefinition_in_param_list) << Name;
12330                  else
12331                    Diag(NameLoc, diag::err_redefinition) << Name;
12332                  Diag(Def->getLocation(), diag::note_previous_definition);
12333                  // If this is a redefinition, recover by making this
12334                  // struct be anonymous, which will make any later
12335                  // references get the previous definition.
12336                  Name = nullptr;
12337                  Previous.clear();
12338                  Invalid = true;
12339                }
12340              } else {
12341                // If the type is currently being defined, complain
12342                // about a nested redefinition.
12343                auto *TD = Context.getTagDeclType(PrevTagDecl)->getAsTagDecl();
12344                if (TD->isBeingDefined()) {
12345                  Diag(NameLoc, diag::err_nested_redefinition) << Name;
12346                  Diag(PrevTagDecl->getLocation(),
12347                       diag::note_previous_definition);
12348                  Name = nullptr;
12349                  Previous.clear();
12350                  Invalid = true;
12351                }
12352              }
12353  
12354              // Okay, this is definition of a previously declared or referenced
12355              // tag. We're going to create a new Decl for it.
12356            }
12357  
12358            // Okay, we're going to make a redeclaration.  If this is some kind
12359            // of reference, make sure we build the redeclaration in the same DC
12360            // as the original, and ignore the current access specifier.
12361            if (TUK == TUK_Friend || TUK == TUK_Reference) {
12362              SearchDC = PrevTagDecl->getDeclContext();
12363              AS = AS_none;
12364            }
12365          }
12366          // If we get here we have (another) forward declaration or we
12367          // have a definition.  Just create a new decl.
12368  
12369        } else {
12370          // If we get here, this is a definition of a new tag type in a nested
12371          // scope, e.g. "struct foo; void bar() { struct foo; }", just create a
12372          // new decl/type.  We set PrevDecl to NULL so that the entities
12373          // have distinct types.
12374          Previous.clear();
12375        }
12376        // If we get here, we're going to create a new Decl. If PrevDecl
12377        // is non-NULL, it's a definition of the tag declared by
12378        // PrevDecl. If it's NULL, we have a new definition.
12379  
12380  
12381      // Otherwise, PrevDecl is not a tag, but was found with tag
12382      // lookup.  This is only actually possible in C++, where a few
12383      // things like templates still live in the tag namespace.
12384      } else {
12385        // Use a better diagnostic if an elaborated-type-specifier
12386        // found the wrong kind of type on the first
12387        // (non-redeclaration) lookup.
12388        if ((TUK == TUK_Reference || TUK == TUK_Friend) &&
12389            !Previous.isForRedeclaration()) {
12390          unsigned Kind = 0;
12391          if (isa<TypedefDecl>(PrevDecl)) Kind = 1;
12392          else if (isa<TypeAliasDecl>(PrevDecl)) Kind = 2;
12393          else if (isa<ClassTemplateDecl>(PrevDecl)) Kind = 3;
12394          Diag(NameLoc, diag::err_tag_reference_non_tag) << Kind;
12395          Diag(PrevDecl->getLocation(), diag::note_declared_at);
12396          Invalid = true;
12397  
12398        // Otherwise, only diagnose if the declaration is in scope.
12399        } else if (!isDeclInScope(DirectPrevDecl, SearchDC, S,
12400                                  SS.isNotEmpty() || isExplicitSpecialization)) {
12401          // do nothing
12402  
12403        // Diagnose implicit declarations introduced by elaborated types.
12404        } else if (TUK == TUK_Reference || TUK == TUK_Friend) {
12405          unsigned Kind = 0;
12406          if (isa<TypedefDecl>(PrevDecl)) Kind = 1;
12407          else if (isa<TypeAliasDecl>(PrevDecl)) Kind = 2;
12408          else if (isa<ClassTemplateDecl>(PrevDecl)) Kind = 3;
12409          Diag(NameLoc, diag::err_tag_reference_conflict) << Kind;
12410          Diag(PrevDecl->getLocation(), diag::note_previous_decl) << PrevDecl;
12411          Invalid = true;
12412  
12413        // Otherwise it's a declaration.  Call out a particularly common
12414        // case here.
12415        } else if (TypedefNameDecl *TND = dyn_cast<TypedefNameDecl>(PrevDecl)) {
12416          unsigned Kind = 0;
12417          if (isa<TypeAliasDecl>(PrevDecl)) Kind = 1;
12418          Diag(NameLoc, diag::err_tag_definition_of_typedef)
12419            << Name << Kind << TND->getUnderlyingType();
12420          Diag(PrevDecl->getLocation(), diag::note_previous_decl) << PrevDecl;
12421          Invalid = true;
12422  
12423        // Otherwise, diagnose.
12424        } else {
12425          // The tag name clashes with something else in the target scope,
12426          // issue an error and recover by making this tag be anonymous.
12427          Diag(NameLoc, diag::err_redefinition_different_kind) << Name;
12428          Diag(PrevDecl->getLocation(), diag::note_previous_definition);
12429          Name = nullptr;
12430          Invalid = true;
12431        }
12432  
12433        // The existing declaration isn't relevant to us; we're in a
12434        // new scope, so clear out the previous declaration.
12435        Previous.clear();
12436      }
12437    }
12438  
12439  CreateNewDecl:
12440  
12441    TagDecl *PrevDecl = nullptr;
12442    if (Previous.isSingleResult())
12443      PrevDecl = cast<TagDecl>(Previous.getFoundDecl());
12444  
12445    // If there is an identifier, use the location of the identifier as the
12446    // location of the decl, otherwise use the location of the struct/union
12447    // keyword.
12448    SourceLocation Loc = NameLoc.isValid() ? NameLoc : KWLoc;
12449  
12450    // Otherwise, create a new declaration. If there is a previous
12451    // declaration of the same entity, the two will be linked via
12452    // PrevDecl.
12453    TagDecl *New;
12454  
12455    bool IsForwardReference = false;
12456    if (Kind == TTK_Enum) {
12457      // FIXME: Tag decls should be chained to any simultaneous vardecls, e.g.:
12458      // enum X { A, B, C } D;    D should chain to X.
12459      New = EnumDecl::Create(Context, SearchDC, KWLoc, Loc, Name,
12460                             cast_or_null<EnumDecl>(PrevDecl), ScopedEnum,
12461                             ScopedEnumUsesClassTag, !EnumUnderlying.isNull());
12462      // If this is an undefined enum, warn.
12463      if (TUK != TUK_Definition && !Invalid) {
12464        TagDecl *Def;
12465        if ((getLangOpts().CPlusPlus11 || getLangOpts().ObjC2) &&
12466            cast<EnumDecl>(New)->isFixed()) {
12467          // C++0x: 7.2p2: opaque-enum-declaration.
12468          // Conflicts are diagnosed above. Do nothing.
12469        }
12470        else if (PrevDecl && (Def = cast<EnumDecl>(PrevDecl)->getDefinition())) {
12471          Diag(Loc, diag::ext_forward_ref_enum_def)
12472            << New;
12473          Diag(Def->getLocation(), diag::note_previous_definition);
12474        } else {
12475          unsigned DiagID = diag::ext_forward_ref_enum;
12476          if (getLangOpts().MSVCCompat)
12477            DiagID = diag::ext_ms_forward_ref_enum;
12478          else if (getLangOpts().CPlusPlus)
12479            DiagID = diag::err_forward_ref_enum;
12480          Diag(Loc, DiagID);
12481  
12482          // If this is a forward-declared reference to an enumeration, make a
12483          // note of it; we won't actually be introducing the declaration into
12484          // the declaration context.
12485          if (TUK == TUK_Reference)
12486            IsForwardReference = true;
12487        }
12488      }
12489  
12490      if (EnumUnderlying) {
12491        EnumDecl *ED = cast<EnumDecl>(New);
12492        if (TypeSourceInfo *TI = EnumUnderlying.dyn_cast<TypeSourceInfo*>())
12493          ED->setIntegerTypeSourceInfo(TI);
12494        else
12495          ED->setIntegerType(QualType(EnumUnderlying.get<const Type*>(), 0));
12496        ED->setPromotionType(ED->getIntegerType());
12497      }
12498  
12499    } else {
12500      // struct/union/class
12501  
12502      // FIXME: Tag decls should be chained to any simultaneous vardecls, e.g.:
12503      // struct X { int A; } D;    D should chain to X.
12504      if (getLangOpts().CPlusPlus) {
12505        // FIXME: Look for a way to use RecordDecl for simple structs.
12506        New = CXXRecordDecl::Create(Context, Kind, SearchDC, KWLoc, Loc, Name,
12507                                    cast_or_null<CXXRecordDecl>(PrevDecl));
12508  
12509        if (isStdBadAlloc && (!StdBadAlloc || getStdBadAlloc()->isImplicit()))
12510          StdBadAlloc = cast<CXXRecordDecl>(New);
12511      } else
12512        New = RecordDecl::Create(Context, Kind, SearchDC, KWLoc, Loc, Name,
12513                                 cast_or_null<RecordDecl>(PrevDecl));
12514    }
12515  
12516    // C++11 [dcl.type]p3:
12517    //   A type-specifier-seq shall not define a class or enumeration [...].
12518    if (getLangOpts().CPlusPlus && IsTypeSpecifier && TUK == TUK_Definition) {
12519      Diag(New->getLocation(), diag::err_type_defined_in_type_specifier)
12520        << Context.getTagDeclType(New);
12521      Invalid = true;
12522    }
12523  
12524    // Maybe add qualifier info.
12525    if (SS.isNotEmpty()) {
12526      if (SS.isSet()) {
12527        // If this is either a declaration or a definition, check the
12528        // nested-name-specifier against the current context. We don't do this
12529        // for explicit specializations, because they have similar checking
12530        // (with more specific diagnostics) in the call to
12531        // CheckMemberSpecialization, below.
12532        if (!isExplicitSpecialization &&
12533            (TUK == TUK_Definition || TUK == TUK_Declaration) &&
12534            diagnoseQualifiedDeclaration(SS, DC, OrigName, Loc))
12535          Invalid = true;
12536  
12537        New->setQualifierInfo(SS.getWithLocInContext(Context));
12538        if (TemplateParameterLists.size() > 0) {
12539          New->setTemplateParameterListsInfo(Context, TemplateParameterLists);
12540        }
12541      }
12542      else
12543        Invalid = true;
12544    }
12545  
12546    if (RecordDecl *RD = dyn_cast<RecordDecl>(New)) {
12547      // Add alignment attributes if necessary; these attributes are checked when
12548      // the ASTContext lays out the structure.
12549      //
12550      // It is important for implementing the correct semantics that this
12551      // happen here (in act on tag decl). The #pragma pack stack is
12552      // maintained as a result of parser callbacks which can occur at
12553      // many points during the parsing of a struct declaration (because
12554      // the #pragma tokens are effectively skipped over during the
12555      // parsing of the struct).
12556      if (TUK == TUK_Definition) {
12557        AddAlignmentAttributesForRecord(RD);
12558        AddMsStructLayoutForRecord(RD);
12559      }
12560    }
12561  
12562    if (ModulePrivateLoc.isValid()) {
12563      if (isExplicitSpecialization)
12564        Diag(New->getLocation(), diag::err_module_private_specialization)
12565          << 2
12566          << FixItHint::CreateRemoval(ModulePrivateLoc);
12567      // __module_private__ does not apply to local classes. However, we only
12568      // diagnose this as an error when the declaration specifiers are
12569      // freestanding. Here, we just ignore the __module_private__.
12570      else if (!SearchDC->isFunctionOrMethod())
12571        New->setModulePrivate();
12572    }
12573  
12574    // If this is a specialization of a member class (of a class template),
12575    // check the specialization.
12576    if (isExplicitSpecialization && CheckMemberSpecialization(New, Previous))
12577      Invalid = true;
12578  
12579    // If we're declaring or defining a tag in function prototype scope in C,
12580    // note that this type can only be used within the function and add it to
12581    // the list of decls to inject into the function definition scope.
12582    if ((Name || Kind == TTK_Enum) &&
12583        getNonFieldDeclScope(S)->isFunctionPrototypeScope()) {
12584      if (getLangOpts().CPlusPlus) {
12585        // C++ [dcl.fct]p6:
12586        //   Types shall not be defined in return or parameter types.
12587        if (TUK == TUK_Definition && !IsTypeSpecifier) {
12588          Diag(Loc, diag::err_type_defined_in_param_type)
12589              << Name;
12590          Invalid = true;
12591        }
12592      } else {
12593        Diag(Loc, diag::warn_decl_in_param_list) << Context.getTagDeclType(New);
12594      }
12595      DeclsInPrototypeScope.push_back(New);
12596    }
12597  
12598    if (Invalid)
12599      New->setInvalidDecl();
12600  
12601    if (Attr)
12602      ProcessDeclAttributeList(S, New, Attr);
12603  
12604    // Set the lexical context. If the tag has a C++ scope specifier, the
12605    // lexical context will be different from the semantic context.
12606    New->setLexicalDeclContext(CurContext);
12607  
12608    // Mark this as a friend decl if applicable.
12609    // In Microsoft mode, a friend declaration also acts as a forward
12610    // declaration so we always pass true to setObjectOfFriendDecl to make
12611    // the tag name visible.
12612    if (TUK == TUK_Friend)
12613      New->setObjectOfFriendDecl(getLangOpts().MSVCCompat);
12614  
12615    // Set the access specifier.
12616    if (!Invalid && SearchDC->isRecord())
12617      SetMemberAccessSpecifier(New, PrevDecl, AS);
12618  
12619    if (TUK == TUK_Definition)
12620      New->startDefinition();
12621  
12622    // If this has an identifier, add it to the scope stack.
12623    if (TUK == TUK_Friend) {
12624      // We might be replacing an existing declaration in the lookup tables;
12625      // if so, borrow its access specifier.
12626      if (PrevDecl)
12627        New->setAccess(PrevDecl->getAccess());
12628  
12629      DeclContext *DC = New->getDeclContext()->getRedeclContext();
12630      DC->makeDeclVisibleInContext(New);
12631      if (Name) // can be null along some error paths
12632        if (Scope *EnclosingScope = getScopeForDeclContext(S, DC))
12633          PushOnScopeChains(New, EnclosingScope, /* AddToContext = */ false);
12634    } else if (Name) {
12635      S = getNonFieldDeclScope(S);
12636      PushOnScopeChains(New, S, !IsForwardReference);
12637      if (IsForwardReference)
12638        SearchDC->makeDeclVisibleInContext(New);
12639  
12640    } else {
12641      CurContext->addDecl(New);
12642    }
12643  
12644    // If this is the C FILE type, notify the AST context.
12645    if (IdentifierInfo *II = New->getIdentifier())
12646      if (!New->isInvalidDecl() &&
12647          New->getDeclContext()->getRedeclContext()->isTranslationUnit() &&
12648          II->isStr("FILE"))
12649        Context.setFILEDecl(New);
12650  
12651    if (PrevDecl)
12652      mergeDeclAttributes(New, PrevDecl);
12653  
12654    // If there's a #pragma GCC visibility in scope, set the visibility of this
12655    // record.
12656    AddPushedVisibilityAttribute(New);
12657  
12658    OwnedDecl = true;
12659    // In C++, don't return an invalid declaration. We can't recover well from
12660    // the cases where we make the type anonymous.
12661    return (Invalid && getLangOpts().CPlusPlus) ? nullptr : New;
12662  }
12663  
ActOnTagStartDefinition(Scope * S,Decl * TagD)12664  void Sema::ActOnTagStartDefinition(Scope *S, Decl *TagD) {
12665    AdjustDeclIfTemplate(TagD);
12666    TagDecl *Tag = cast<TagDecl>(TagD);
12667  
12668    // Enter the tag context.
12669    PushDeclContext(S, Tag);
12670  
12671    ActOnDocumentableDecl(TagD);
12672  
12673    // If there's a #pragma GCC visibility in scope, set the visibility of this
12674    // record.
12675    AddPushedVisibilityAttribute(Tag);
12676  }
12677  
ActOnObjCContainerStartDefinition(Decl * IDecl)12678  Decl *Sema::ActOnObjCContainerStartDefinition(Decl *IDecl) {
12679    assert(isa<ObjCContainerDecl>(IDecl) &&
12680           "ActOnObjCContainerStartDefinition - Not ObjCContainerDecl");
12681    DeclContext *OCD = cast<DeclContext>(IDecl);
12682    assert(getContainingDC(OCD) == CurContext &&
12683        "The next DeclContext should be lexically contained in the current one.");
12684    CurContext = OCD;
12685    return IDecl;
12686  }
12687  
ActOnStartCXXMemberDeclarations(Scope * S,Decl * TagD,SourceLocation FinalLoc,bool IsFinalSpelledSealed,SourceLocation LBraceLoc)12688  void Sema::ActOnStartCXXMemberDeclarations(Scope *S, Decl *TagD,
12689                                             SourceLocation FinalLoc,
12690                                             bool IsFinalSpelledSealed,
12691                                             SourceLocation LBraceLoc) {
12692    AdjustDeclIfTemplate(TagD);
12693    CXXRecordDecl *Record = cast<CXXRecordDecl>(TagD);
12694  
12695    FieldCollector->StartClass();
12696  
12697    if (!Record->getIdentifier())
12698      return;
12699  
12700    if (FinalLoc.isValid())
12701      Record->addAttr(new (Context)
12702                      FinalAttr(FinalLoc, Context, IsFinalSpelledSealed));
12703  
12704    // C++ [class]p2:
12705    //   [...] The class-name is also inserted into the scope of the
12706    //   class itself; this is known as the injected-class-name. For
12707    //   purposes of access checking, the injected-class-name is treated
12708    //   as if it were a public member name.
12709    CXXRecordDecl *InjectedClassName
12710      = CXXRecordDecl::Create(Context, Record->getTagKind(), CurContext,
12711                              Record->getLocStart(), Record->getLocation(),
12712                              Record->getIdentifier(),
12713                              /*PrevDecl=*/nullptr,
12714                              /*DelayTypeCreation=*/true);
12715    Context.getTypeDeclType(InjectedClassName, Record);
12716    InjectedClassName->setImplicit();
12717    InjectedClassName->setAccess(AS_public);
12718    if (ClassTemplateDecl *Template = Record->getDescribedClassTemplate())
12719        InjectedClassName->setDescribedClassTemplate(Template);
12720    PushOnScopeChains(InjectedClassName, S);
12721    assert(InjectedClassName->isInjectedClassName() &&
12722           "Broken injected-class-name");
12723  }
12724  
ActOnTagFinishDefinition(Scope * S,Decl * TagD,SourceLocation RBraceLoc)12725  void Sema::ActOnTagFinishDefinition(Scope *S, Decl *TagD,
12726                                      SourceLocation RBraceLoc) {
12727    AdjustDeclIfTemplate(TagD);
12728    TagDecl *Tag = cast<TagDecl>(TagD);
12729    Tag->setRBraceLoc(RBraceLoc);
12730  
12731    // Make sure we "complete" the definition even it is invalid.
12732    if (Tag->isBeingDefined()) {
12733      assert(Tag->isInvalidDecl() && "We should already have completed it");
12734      if (RecordDecl *RD = dyn_cast<RecordDecl>(Tag))
12735        RD->completeDefinition();
12736    }
12737  
12738    if (isa<CXXRecordDecl>(Tag))
12739      FieldCollector->FinishClass();
12740  
12741    // Exit this scope of this tag's definition.
12742    PopDeclContext();
12743  
12744    if (getCurLexicalContext()->isObjCContainer() &&
12745        Tag->getDeclContext()->isFileContext())
12746      Tag->setTopLevelDeclInObjCContainer();
12747  
12748    // Notify the consumer that we've defined a tag.
12749    if (!Tag->isInvalidDecl())
12750      Consumer.HandleTagDeclDefinition(Tag);
12751  }
12752  
ActOnObjCContainerFinishDefinition()12753  void Sema::ActOnObjCContainerFinishDefinition() {
12754    // Exit this scope of this interface definition.
12755    PopDeclContext();
12756  }
12757  
ActOnObjCTemporaryExitContainerContext(DeclContext * DC)12758  void Sema::ActOnObjCTemporaryExitContainerContext(DeclContext *DC) {
12759    assert(DC == CurContext && "Mismatch of container contexts");
12760    OriginalLexicalContext = DC;
12761    ActOnObjCContainerFinishDefinition();
12762  }
12763  
ActOnObjCReenterContainerContext(DeclContext * DC)12764  void Sema::ActOnObjCReenterContainerContext(DeclContext *DC) {
12765    ActOnObjCContainerStartDefinition(cast<Decl>(DC));
12766    OriginalLexicalContext = nullptr;
12767  }
12768  
ActOnTagDefinitionError(Scope * S,Decl * TagD)12769  void Sema::ActOnTagDefinitionError(Scope *S, Decl *TagD) {
12770    AdjustDeclIfTemplate(TagD);
12771    TagDecl *Tag = cast<TagDecl>(TagD);
12772    Tag->setInvalidDecl();
12773  
12774    // Make sure we "complete" the definition even it is invalid.
12775    if (Tag->isBeingDefined()) {
12776      if (RecordDecl *RD = dyn_cast<RecordDecl>(Tag))
12777        RD->completeDefinition();
12778    }
12779  
12780    // We're undoing ActOnTagStartDefinition here, not
12781    // ActOnStartCXXMemberDeclarations, so we don't have to mess with
12782    // the FieldCollector.
12783  
12784    PopDeclContext();
12785  }
12786  
12787  // Note that FieldName may be null for anonymous bitfields.
VerifyBitField(SourceLocation FieldLoc,IdentifierInfo * FieldName,QualType FieldTy,bool IsMsStruct,Expr * BitWidth,bool * ZeroWidth)12788  ExprResult Sema::VerifyBitField(SourceLocation FieldLoc,
12789                                  IdentifierInfo *FieldName,
12790                                  QualType FieldTy, bool IsMsStruct,
12791                                  Expr *BitWidth, bool *ZeroWidth) {
12792    // Default to true; that shouldn't confuse checks for emptiness
12793    if (ZeroWidth)
12794      *ZeroWidth = true;
12795  
12796    // C99 6.7.2.1p4 - verify the field type.
12797    // C++ 9.6p3: A bit-field shall have integral or enumeration type.
12798    if (!FieldTy->isDependentType() && !FieldTy->isIntegralOrEnumerationType()) {
12799      // Handle incomplete types with specific error.
12800      if (RequireCompleteType(FieldLoc, FieldTy, diag::err_field_incomplete))
12801        return ExprError();
12802      if (FieldName)
12803        return Diag(FieldLoc, diag::err_not_integral_type_bitfield)
12804          << FieldName << FieldTy << BitWidth->getSourceRange();
12805      return Diag(FieldLoc, diag::err_not_integral_type_anon_bitfield)
12806        << FieldTy << BitWidth->getSourceRange();
12807    } else if (DiagnoseUnexpandedParameterPack(const_cast<Expr *>(BitWidth),
12808                                               UPPC_BitFieldWidth))
12809      return ExprError();
12810  
12811    // If the bit-width is type- or value-dependent, don't try to check
12812    // it now.
12813    if (BitWidth->isValueDependent() || BitWidth->isTypeDependent())
12814      return BitWidth;
12815  
12816    llvm::APSInt Value;
12817    ExprResult ICE = VerifyIntegerConstantExpression(BitWidth, &Value);
12818    if (ICE.isInvalid())
12819      return ICE;
12820    BitWidth = ICE.get();
12821  
12822    if (Value != 0 && ZeroWidth)
12823      *ZeroWidth = false;
12824  
12825    // Zero-width bitfield is ok for anonymous field.
12826    if (Value == 0 && FieldName)
12827      return Diag(FieldLoc, diag::err_bitfield_has_zero_width) << FieldName;
12828  
12829    if (Value.isSigned() && Value.isNegative()) {
12830      if (FieldName)
12831        return Diag(FieldLoc, diag::err_bitfield_has_negative_width)
12832                 << FieldName << Value.toString(10);
12833      return Diag(FieldLoc, diag::err_anon_bitfield_has_negative_width)
12834        << Value.toString(10);
12835    }
12836  
12837    if (!FieldTy->isDependentType()) {
12838      uint64_t TypeStorageSize = Context.getTypeSize(FieldTy);
12839      uint64_t TypeWidth = Context.getIntWidth(FieldTy);
12840      bool BitfieldIsOverwide = Value.ugt(TypeWidth);
12841  
12842      // Over-wide bitfields are an error in C or when using the MSVC bitfield
12843      // ABI.
12844      bool CStdConstraintViolation =
12845          BitfieldIsOverwide && !getLangOpts().CPlusPlus;
12846      bool MSBitfieldViolation =
12847          Value.ugt(TypeStorageSize) &&
12848          (IsMsStruct || Context.getTargetInfo().getCXXABI().isMicrosoft());
12849      if (CStdConstraintViolation || MSBitfieldViolation) {
12850        unsigned DiagWidth =
12851            CStdConstraintViolation ? TypeWidth : TypeStorageSize;
12852        if (FieldName)
12853          return Diag(FieldLoc, diag::err_bitfield_width_exceeds_type_width)
12854                 << FieldName << (unsigned)Value.getZExtValue()
12855                 << !CStdConstraintViolation << DiagWidth;
12856  
12857        return Diag(FieldLoc, diag::err_anon_bitfield_width_exceeds_type_width)
12858               << (unsigned)Value.getZExtValue() << !CStdConstraintViolation
12859               << DiagWidth;
12860      }
12861  
12862      // Warn on types where the user might conceivably expect to get all
12863      // specified bits as value bits: that's all integral types other than
12864      // 'bool'.
12865      if (BitfieldIsOverwide && !FieldTy->isBooleanType()) {
12866        if (FieldName)
12867          Diag(FieldLoc, diag::warn_bitfield_width_exceeds_type_width)
12868              << FieldName << (unsigned)Value.getZExtValue()
12869              << (unsigned)TypeWidth;
12870        else
12871          Diag(FieldLoc, diag::warn_anon_bitfield_width_exceeds_type_width)
12872              << (unsigned)Value.getZExtValue() << (unsigned)TypeWidth;
12873      }
12874    }
12875  
12876    return BitWidth;
12877  }
12878  
12879  /// ActOnField - Each field of a C struct/union is passed into this in order
12880  /// to create a FieldDecl object for it.
ActOnField(Scope * S,Decl * TagD,SourceLocation DeclStart,Declarator & D,Expr * BitfieldWidth)12881  Decl *Sema::ActOnField(Scope *S, Decl *TagD, SourceLocation DeclStart,
12882                         Declarator &D, Expr *BitfieldWidth) {
12883    FieldDecl *Res = HandleField(S, cast_or_null<RecordDecl>(TagD),
12884                                 DeclStart, D, static_cast<Expr*>(BitfieldWidth),
12885                                 /*InitStyle=*/ICIS_NoInit, AS_public);
12886    return Res;
12887  }
12888  
12889  /// HandleField - Analyze a field of a C struct or a C++ data member.
12890  ///
HandleField(Scope * S,RecordDecl * Record,SourceLocation DeclStart,Declarator & D,Expr * BitWidth,InClassInitStyle InitStyle,AccessSpecifier AS)12891  FieldDecl *Sema::HandleField(Scope *S, RecordDecl *Record,
12892                               SourceLocation DeclStart,
12893                               Declarator &D, Expr *BitWidth,
12894                               InClassInitStyle InitStyle,
12895                               AccessSpecifier AS) {
12896    IdentifierInfo *II = D.getIdentifier();
12897    SourceLocation Loc = DeclStart;
12898    if (II) Loc = D.getIdentifierLoc();
12899  
12900    TypeSourceInfo *TInfo = GetTypeForDeclarator(D, S);
12901    QualType T = TInfo->getType();
12902    if (getLangOpts().CPlusPlus) {
12903      CheckExtraCXXDefaultArguments(D);
12904  
12905      if (DiagnoseUnexpandedParameterPack(D.getIdentifierLoc(), TInfo,
12906                                          UPPC_DataMemberType)) {
12907        D.setInvalidType();
12908        T = Context.IntTy;
12909        TInfo = Context.getTrivialTypeSourceInfo(T, Loc);
12910      }
12911    }
12912  
12913    // TR 18037 does not allow fields to be declared with address spaces.
12914    if (T.getQualifiers().hasAddressSpace()) {
12915      Diag(Loc, diag::err_field_with_address_space);
12916      D.setInvalidType();
12917    }
12918  
12919    // OpenCL 1.2 spec, s6.9 r:
12920    // The event type cannot be used to declare a structure or union field.
12921    if (LangOpts.OpenCL && T->isEventT()) {
12922      Diag(Loc, diag::err_event_t_struct_field);
12923      D.setInvalidType();
12924    }
12925  
12926    DiagnoseFunctionSpecifiers(D.getDeclSpec());
12927  
12928    if (DeclSpec::TSCS TSCS = D.getDeclSpec().getThreadStorageClassSpec())
12929      Diag(D.getDeclSpec().getThreadStorageClassSpecLoc(),
12930           diag::err_invalid_thread)
12931        << DeclSpec::getSpecifierName(TSCS);
12932  
12933    // Check to see if this name was declared as a member previously
12934    NamedDecl *PrevDecl = nullptr;
12935    LookupResult Previous(*this, II, Loc, LookupMemberName, ForRedeclaration);
12936    LookupName(Previous, S);
12937    switch (Previous.getResultKind()) {
12938      case LookupResult::Found:
12939      case LookupResult::FoundUnresolvedValue:
12940        PrevDecl = Previous.getAsSingle<NamedDecl>();
12941        break;
12942  
12943      case LookupResult::FoundOverloaded:
12944        PrevDecl = Previous.getRepresentativeDecl();
12945        break;
12946  
12947      case LookupResult::NotFound:
12948      case LookupResult::NotFoundInCurrentInstantiation:
12949      case LookupResult::Ambiguous:
12950        break;
12951    }
12952    Previous.suppressDiagnostics();
12953  
12954    if (PrevDecl && PrevDecl->isTemplateParameter()) {
12955      // Maybe we will complain about the shadowed template parameter.
12956      DiagnoseTemplateParameterShadow(D.getIdentifierLoc(), PrevDecl);
12957      // Just pretend that we didn't see the previous declaration.
12958      PrevDecl = nullptr;
12959    }
12960  
12961    if (PrevDecl && !isDeclInScope(PrevDecl, Record, S))
12962      PrevDecl = nullptr;
12963  
12964    bool Mutable
12965      = (D.getDeclSpec().getStorageClassSpec() == DeclSpec::SCS_mutable);
12966    SourceLocation TSSL = D.getLocStart();
12967    FieldDecl *NewFD
12968      = CheckFieldDecl(II, T, TInfo, Record, Loc, Mutable, BitWidth, InitStyle,
12969                       TSSL, AS, PrevDecl, &D);
12970  
12971    if (NewFD->isInvalidDecl())
12972      Record->setInvalidDecl();
12973  
12974    if (D.getDeclSpec().isModulePrivateSpecified())
12975      NewFD->setModulePrivate();
12976  
12977    if (NewFD->isInvalidDecl() && PrevDecl) {
12978      // Don't introduce NewFD into scope; there's already something
12979      // with the same name in the same scope.
12980    } else if (II) {
12981      PushOnScopeChains(NewFD, S);
12982    } else
12983      Record->addDecl(NewFD);
12984  
12985    return NewFD;
12986  }
12987  
12988  /// \brief Build a new FieldDecl and check its well-formedness.
12989  ///
12990  /// This routine builds a new FieldDecl given the fields name, type,
12991  /// record, etc. \p PrevDecl should refer to any previous declaration
12992  /// with the same name and in the same scope as the field to be
12993  /// created.
12994  ///
12995  /// \returns a new FieldDecl.
12996  ///
12997  /// \todo The Declarator argument is a hack. It will be removed once
CheckFieldDecl(DeclarationName Name,QualType T,TypeSourceInfo * TInfo,RecordDecl * Record,SourceLocation Loc,bool Mutable,Expr * BitWidth,InClassInitStyle InitStyle,SourceLocation TSSL,AccessSpecifier AS,NamedDecl * PrevDecl,Declarator * D)12998  FieldDecl *Sema::CheckFieldDecl(DeclarationName Name, QualType T,
12999                                  TypeSourceInfo *TInfo,
13000                                  RecordDecl *Record, SourceLocation Loc,
13001                                  bool Mutable, Expr *BitWidth,
13002                                  InClassInitStyle InitStyle,
13003                                  SourceLocation TSSL,
13004                                  AccessSpecifier AS, NamedDecl *PrevDecl,
13005                                  Declarator *D) {
13006    IdentifierInfo *II = Name.getAsIdentifierInfo();
13007    bool InvalidDecl = false;
13008    if (D) InvalidDecl = D->isInvalidType();
13009  
13010    // If we receive a broken type, recover by assuming 'int' and
13011    // marking this declaration as invalid.
13012    if (T.isNull()) {
13013      InvalidDecl = true;
13014      T = Context.IntTy;
13015    }
13016  
13017    QualType EltTy = Context.getBaseElementType(T);
13018    if (!EltTy->isDependentType()) {
13019      if (RequireCompleteType(Loc, EltTy, diag::err_field_incomplete)) {
13020        // Fields of incomplete type force their record to be invalid.
13021        Record->setInvalidDecl();
13022        InvalidDecl = true;
13023      } else {
13024        NamedDecl *Def;
13025        EltTy->isIncompleteType(&Def);
13026        if (Def && Def->isInvalidDecl()) {
13027          Record->setInvalidDecl();
13028          InvalidDecl = true;
13029        }
13030      }
13031    }
13032  
13033    // OpenCL v1.2 s6.9.c: bitfields are not supported.
13034    if (BitWidth && getLangOpts().OpenCL) {
13035      Diag(Loc, diag::err_opencl_bitfields);
13036      InvalidDecl = true;
13037    }
13038  
13039    // C99 6.7.2.1p8: A member of a structure or union may have any type other
13040    // than a variably modified type.
13041    if (!InvalidDecl && T->isVariablyModifiedType()) {
13042      bool SizeIsNegative;
13043      llvm::APSInt Oversized;
13044  
13045      TypeSourceInfo *FixedTInfo =
13046        TryToFixInvalidVariablyModifiedTypeSourceInfo(TInfo, Context,
13047                                                      SizeIsNegative,
13048                                                      Oversized);
13049      if (FixedTInfo) {
13050        Diag(Loc, diag::warn_illegal_constant_array_size);
13051        TInfo = FixedTInfo;
13052        T = FixedTInfo->getType();
13053      } else {
13054        if (SizeIsNegative)
13055          Diag(Loc, diag::err_typecheck_negative_array_size);
13056        else if (Oversized.getBoolValue())
13057          Diag(Loc, diag::err_array_too_large)
13058            << Oversized.toString(10);
13059        else
13060          Diag(Loc, diag::err_typecheck_field_variable_size);
13061        InvalidDecl = true;
13062      }
13063    }
13064  
13065    // Fields can not have abstract class types
13066    if (!InvalidDecl && RequireNonAbstractType(Loc, T,
13067                                               diag::err_abstract_type_in_decl,
13068                                               AbstractFieldType))
13069      InvalidDecl = true;
13070  
13071    bool ZeroWidth = false;
13072    if (InvalidDecl)
13073      BitWidth = nullptr;
13074    // If this is declared as a bit-field, check the bit-field.
13075    if (BitWidth) {
13076      BitWidth = VerifyBitField(Loc, II, T, Record->isMsStruct(Context), BitWidth,
13077                                &ZeroWidth).get();
13078      if (!BitWidth) {
13079        InvalidDecl = true;
13080        BitWidth = nullptr;
13081        ZeroWidth = false;
13082      }
13083    }
13084  
13085    // Check that 'mutable' is consistent with the type of the declaration.
13086    if (!InvalidDecl && Mutable) {
13087      unsigned DiagID = 0;
13088      if (T->isReferenceType())
13089        DiagID = getLangOpts().MSVCCompat ? diag::ext_mutable_reference
13090                                          : diag::err_mutable_reference;
13091      else if (T.isConstQualified())
13092        DiagID = diag::err_mutable_const;
13093  
13094      if (DiagID) {
13095        SourceLocation ErrLoc = Loc;
13096        if (D && D->getDeclSpec().getStorageClassSpecLoc().isValid())
13097          ErrLoc = D->getDeclSpec().getStorageClassSpecLoc();
13098        Diag(ErrLoc, DiagID);
13099        if (DiagID != diag::ext_mutable_reference) {
13100          Mutable = false;
13101          InvalidDecl = true;
13102        }
13103      }
13104    }
13105  
13106    // C++11 [class.union]p8 (DR1460):
13107    //   At most one variant member of a union may have a
13108    //   brace-or-equal-initializer.
13109    if (InitStyle != ICIS_NoInit)
13110      checkDuplicateDefaultInit(*this, cast<CXXRecordDecl>(Record), Loc);
13111  
13112    FieldDecl *NewFD = FieldDecl::Create(Context, Record, TSSL, Loc, II, T, TInfo,
13113                                         BitWidth, Mutable, InitStyle);
13114    if (InvalidDecl)
13115      NewFD->setInvalidDecl();
13116  
13117    if (PrevDecl && !isa<TagDecl>(PrevDecl)) {
13118      Diag(Loc, diag::err_duplicate_member) << II;
13119      Diag(PrevDecl->getLocation(), diag::note_previous_declaration);
13120      NewFD->setInvalidDecl();
13121    }
13122  
13123    if (!InvalidDecl && getLangOpts().CPlusPlus) {
13124      if (Record->isUnion()) {
13125        if (const RecordType *RT = EltTy->getAs<RecordType>()) {
13126          CXXRecordDecl* RDecl = cast<CXXRecordDecl>(RT->getDecl());
13127          if (RDecl->getDefinition()) {
13128            // C++ [class.union]p1: An object of a class with a non-trivial
13129            // constructor, a non-trivial copy constructor, a non-trivial
13130            // destructor, or a non-trivial copy assignment operator
13131            // cannot be a member of a union, nor can an array of such
13132            // objects.
13133            if (CheckNontrivialField(NewFD))
13134              NewFD->setInvalidDecl();
13135          }
13136        }
13137  
13138        // C++ [class.union]p1: If a union contains a member of reference type,
13139        // the program is ill-formed, except when compiling with MSVC extensions
13140        // enabled.
13141        if (EltTy->isReferenceType()) {
13142          Diag(NewFD->getLocation(), getLangOpts().MicrosoftExt ?
13143                                      diag::ext_union_member_of_reference_type :
13144                                      diag::err_union_member_of_reference_type)
13145            << NewFD->getDeclName() << EltTy;
13146          if (!getLangOpts().MicrosoftExt)
13147            NewFD->setInvalidDecl();
13148        }
13149      }
13150    }
13151  
13152    // FIXME: We need to pass in the attributes given an AST
13153    // representation, not a parser representation.
13154    if (D) {
13155      // FIXME: The current scope is almost... but not entirely... correct here.
13156      ProcessDeclAttributes(getCurScope(), NewFD, *D);
13157  
13158      if (NewFD->hasAttrs())
13159        CheckAlignasUnderalignment(NewFD);
13160    }
13161  
13162    // In auto-retain/release, infer strong retension for fields of
13163    // retainable type.
13164    if (getLangOpts().ObjCAutoRefCount && inferObjCARCLifetime(NewFD))
13165      NewFD->setInvalidDecl();
13166  
13167    if (T.isObjCGCWeak())
13168      Diag(Loc, diag::warn_attribute_weak_on_field);
13169  
13170    NewFD->setAccess(AS);
13171    return NewFD;
13172  }
13173  
CheckNontrivialField(FieldDecl * FD)13174  bool Sema::CheckNontrivialField(FieldDecl *FD) {
13175    assert(FD);
13176    assert(getLangOpts().CPlusPlus && "valid check only for C++");
13177  
13178    if (FD->isInvalidDecl() || FD->getType()->isDependentType())
13179      return false;
13180  
13181    QualType EltTy = Context.getBaseElementType(FD->getType());
13182    if (const RecordType *RT = EltTy->getAs<RecordType>()) {
13183      CXXRecordDecl *RDecl = cast<CXXRecordDecl>(RT->getDecl());
13184      if (RDecl->getDefinition()) {
13185        // We check for copy constructors before constructors
13186        // because otherwise we'll never get complaints about
13187        // copy constructors.
13188  
13189        CXXSpecialMember member = CXXInvalid;
13190        // We're required to check for any non-trivial constructors. Since the
13191        // implicit default constructor is suppressed if there are any
13192        // user-declared constructors, we just need to check that there is a
13193        // trivial default constructor and a trivial copy constructor. (We don't
13194        // worry about move constructors here, since this is a C++98 check.)
13195        if (RDecl->hasNonTrivialCopyConstructor())
13196          member = CXXCopyConstructor;
13197        else if (!RDecl->hasTrivialDefaultConstructor())
13198          member = CXXDefaultConstructor;
13199        else if (RDecl->hasNonTrivialCopyAssignment())
13200          member = CXXCopyAssignment;
13201        else if (RDecl->hasNonTrivialDestructor())
13202          member = CXXDestructor;
13203  
13204        if (member != CXXInvalid) {
13205          if (!getLangOpts().CPlusPlus11 &&
13206              getLangOpts().ObjCAutoRefCount && RDecl->hasObjectMember()) {
13207            // Objective-C++ ARC: it is an error to have a non-trivial field of
13208            // a union. However, system headers in Objective-C programs
13209            // occasionally have Objective-C lifetime objects within unions,
13210            // and rather than cause the program to fail, we make those
13211            // members unavailable.
13212            SourceLocation Loc = FD->getLocation();
13213            if (getSourceManager().isInSystemHeader(Loc)) {
13214              if (!FD->hasAttr<UnavailableAttr>())
13215                FD->addAttr(UnavailableAttr::CreateImplicit(Context, "",
13216                              UnavailableAttr::IR_ARCFieldWithOwnership, Loc));
13217              return false;
13218            }
13219          }
13220  
13221          Diag(FD->getLocation(), getLangOpts().CPlusPlus11 ?
13222                 diag::warn_cxx98_compat_nontrivial_union_or_anon_struct_member :
13223                 diag::err_illegal_union_or_anon_struct_member)
13224            << FD->getParent()->isUnion() << FD->getDeclName() << member;
13225          DiagnoseNontrivial(RDecl, member);
13226          return !getLangOpts().CPlusPlus11;
13227        }
13228      }
13229    }
13230  
13231    return false;
13232  }
13233  
13234  /// TranslateIvarVisibility - Translate visibility from a token ID to an
13235  ///  AST enum value.
13236  static ObjCIvarDecl::AccessControl
TranslateIvarVisibility(tok::ObjCKeywordKind ivarVisibility)13237  TranslateIvarVisibility(tok::ObjCKeywordKind ivarVisibility) {
13238    switch (ivarVisibility) {
13239    default: llvm_unreachable("Unknown visitibility kind");
13240    case tok::objc_private: return ObjCIvarDecl::Private;
13241    case tok::objc_public: return ObjCIvarDecl::Public;
13242    case tok::objc_protected: return ObjCIvarDecl::Protected;
13243    case tok::objc_package: return ObjCIvarDecl::Package;
13244    }
13245  }
13246  
13247  /// ActOnIvar - Each ivar field of an objective-c class is passed into this
13248  /// in order to create an IvarDecl object for it.
ActOnIvar(Scope * S,SourceLocation DeclStart,Declarator & D,Expr * BitfieldWidth,tok::ObjCKeywordKind Visibility)13249  Decl *Sema::ActOnIvar(Scope *S,
13250                                  SourceLocation DeclStart,
13251                                  Declarator &D, Expr *BitfieldWidth,
13252                                  tok::ObjCKeywordKind Visibility) {
13253  
13254    IdentifierInfo *II = D.getIdentifier();
13255    Expr *BitWidth = (Expr*)BitfieldWidth;
13256    SourceLocation Loc = DeclStart;
13257    if (II) Loc = D.getIdentifierLoc();
13258  
13259    // FIXME: Unnamed fields can be handled in various different ways, for
13260    // example, unnamed unions inject all members into the struct namespace!
13261  
13262    TypeSourceInfo *TInfo = GetTypeForDeclarator(D, S);
13263    QualType T = TInfo->getType();
13264  
13265    if (BitWidth) {
13266      // 6.7.2.1p3, 6.7.2.1p4
13267      BitWidth = VerifyBitField(Loc, II, T, /*IsMsStruct*/false, BitWidth).get();
13268      if (!BitWidth)
13269        D.setInvalidType();
13270    } else {
13271      // Not a bitfield.
13272  
13273      // validate II.
13274  
13275    }
13276    if (T->isReferenceType()) {
13277      Diag(Loc, diag::err_ivar_reference_type);
13278      D.setInvalidType();
13279    }
13280    // C99 6.7.2.1p8: A member of a structure or union may have any type other
13281    // than a variably modified type.
13282    else if (T->isVariablyModifiedType()) {
13283      Diag(Loc, diag::err_typecheck_ivar_variable_size);
13284      D.setInvalidType();
13285    }
13286  
13287    // Get the visibility (access control) for this ivar.
13288    ObjCIvarDecl::AccessControl ac =
13289      Visibility != tok::objc_not_keyword ? TranslateIvarVisibility(Visibility)
13290                                          : ObjCIvarDecl::None;
13291    // Must set ivar's DeclContext to its enclosing interface.
13292    ObjCContainerDecl *EnclosingDecl = cast<ObjCContainerDecl>(CurContext);
13293    if (!EnclosingDecl || EnclosingDecl->isInvalidDecl())
13294      return nullptr;
13295    ObjCContainerDecl *EnclosingContext;
13296    if (ObjCImplementationDecl *IMPDecl =
13297        dyn_cast<ObjCImplementationDecl>(EnclosingDecl)) {
13298      if (LangOpts.ObjCRuntime.isFragile()) {
13299      // Case of ivar declared in an implementation. Context is that of its class.
13300        EnclosingContext = IMPDecl->getClassInterface();
13301        assert(EnclosingContext && "Implementation has no class interface!");
13302      }
13303      else
13304        EnclosingContext = EnclosingDecl;
13305    } else {
13306      if (ObjCCategoryDecl *CDecl =
13307          dyn_cast<ObjCCategoryDecl>(EnclosingDecl)) {
13308        if (LangOpts.ObjCRuntime.isFragile() || !CDecl->IsClassExtension()) {
13309          Diag(Loc, diag::err_misplaced_ivar) << CDecl->IsClassExtension();
13310          return nullptr;
13311        }
13312      }
13313      EnclosingContext = EnclosingDecl;
13314    }
13315  
13316    // Construct the decl.
13317    ObjCIvarDecl *NewID = ObjCIvarDecl::Create(Context, EnclosingContext,
13318                                               DeclStart, Loc, II, T,
13319                                               TInfo, ac, (Expr *)BitfieldWidth);
13320  
13321    if (II) {
13322      NamedDecl *PrevDecl = LookupSingleName(S, II, Loc, LookupMemberName,
13323                                             ForRedeclaration);
13324      if (PrevDecl && isDeclInScope(PrevDecl, EnclosingContext, S)
13325          && !isa<TagDecl>(PrevDecl)) {
13326        Diag(Loc, diag::err_duplicate_member) << II;
13327        Diag(PrevDecl->getLocation(), diag::note_previous_declaration);
13328        NewID->setInvalidDecl();
13329      }
13330    }
13331  
13332    // Process attributes attached to the ivar.
13333    ProcessDeclAttributes(S, NewID, D);
13334  
13335    if (D.isInvalidType())
13336      NewID->setInvalidDecl();
13337  
13338    // In ARC, infer 'retaining' for ivars of retainable type.
13339    if (getLangOpts().ObjCAutoRefCount && inferObjCARCLifetime(NewID))
13340      NewID->setInvalidDecl();
13341  
13342    if (D.getDeclSpec().isModulePrivateSpecified())
13343      NewID->setModulePrivate();
13344  
13345    if (II) {
13346      // FIXME: When interfaces are DeclContexts, we'll need to add
13347      // these to the interface.
13348      S->AddDecl(NewID);
13349      IdResolver.AddDecl(NewID);
13350    }
13351  
13352    if (LangOpts.ObjCRuntime.isNonFragile() &&
13353        !NewID->isInvalidDecl() && isa<ObjCInterfaceDecl>(EnclosingDecl))
13354      Diag(Loc, diag::warn_ivars_in_interface);
13355  
13356    return NewID;
13357  }
13358  
13359  /// ActOnLastBitfield - This routine handles synthesized bitfields rules for
13360  /// class and class extensions. For every class \@interface and class
13361  /// extension \@interface, if the last ivar is a bitfield of any type,
13362  /// then add an implicit `char :0` ivar to the end of that interface.
ActOnLastBitfield(SourceLocation DeclLoc,SmallVectorImpl<Decl * > & AllIvarDecls)13363  void Sema::ActOnLastBitfield(SourceLocation DeclLoc,
13364                               SmallVectorImpl<Decl *> &AllIvarDecls) {
13365    if (LangOpts.ObjCRuntime.isFragile() || AllIvarDecls.empty())
13366      return;
13367  
13368    Decl *ivarDecl = AllIvarDecls[AllIvarDecls.size()-1];
13369    ObjCIvarDecl *Ivar = cast<ObjCIvarDecl>(ivarDecl);
13370  
13371    if (!Ivar->isBitField() || Ivar->getBitWidthValue(Context) == 0)
13372      return;
13373    ObjCInterfaceDecl *ID = dyn_cast<ObjCInterfaceDecl>(CurContext);
13374    if (!ID) {
13375      if (ObjCCategoryDecl *CD = dyn_cast<ObjCCategoryDecl>(CurContext)) {
13376        if (!CD->IsClassExtension())
13377          return;
13378      }
13379      // No need to add this to end of @implementation.
13380      else
13381        return;
13382    }
13383    // All conditions are met. Add a new bitfield to the tail end of ivars.
13384    llvm::APInt Zero(Context.getTypeSize(Context.IntTy), 0);
13385    Expr * BW = IntegerLiteral::Create(Context, Zero, Context.IntTy, DeclLoc);
13386  
13387    Ivar = ObjCIvarDecl::Create(Context, cast<ObjCContainerDecl>(CurContext),
13388                                DeclLoc, DeclLoc, nullptr,
13389                                Context.CharTy,
13390                                Context.getTrivialTypeSourceInfo(Context.CharTy,
13391                                                                 DeclLoc),
13392                                ObjCIvarDecl::Private, BW,
13393                                true);
13394    AllIvarDecls.push_back(Ivar);
13395  }
13396  
ActOnFields(Scope * S,SourceLocation RecLoc,Decl * EnclosingDecl,ArrayRef<Decl * > Fields,SourceLocation LBrac,SourceLocation RBrac,AttributeList * Attr)13397  void Sema::ActOnFields(Scope *S, SourceLocation RecLoc, Decl *EnclosingDecl,
13398                         ArrayRef<Decl *> Fields, SourceLocation LBrac,
13399                         SourceLocation RBrac, AttributeList *Attr) {
13400    assert(EnclosingDecl && "missing record or interface decl");
13401  
13402    // If this is an Objective-C @implementation or category and we have
13403    // new fields here we should reset the layout of the interface since
13404    // it will now change.
13405    if (!Fields.empty() && isa<ObjCContainerDecl>(EnclosingDecl)) {
13406      ObjCContainerDecl *DC = cast<ObjCContainerDecl>(EnclosingDecl);
13407      switch (DC->getKind()) {
13408      default: break;
13409      case Decl::ObjCCategory:
13410        Context.ResetObjCLayout(cast<ObjCCategoryDecl>(DC)->getClassInterface());
13411        break;
13412      case Decl::ObjCImplementation:
13413        Context.
13414          ResetObjCLayout(cast<ObjCImplementationDecl>(DC)->getClassInterface());
13415        break;
13416      }
13417    }
13418  
13419    RecordDecl *Record = dyn_cast<RecordDecl>(EnclosingDecl);
13420  
13421    // Start counting up the number of named members; make sure to include
13422    // members of anonymous structs and unions in the total.
13423    unsigned NumNamedMembers = 0;
13424    if (Record) {
13425      for (const auto *I : Record->decls()) {
13426        if (const auto *IFD = dyn_cast<IndirectFieldDecl>(I))
13427          if (IFD->getDeclName())
13428            ++NumNamedMembers;
13429      }
13430    }
13431  
13432    // Verify that all the fields are okay.
13433    SmallVector<FieldDecl*, 32> RecFields;
13434  
13435    bool ARCErrReported = false;
13436    for (ArrayRef<Decl *>::iterator i = Fields.begin(), end = Fields.end();
13437         i != end; ++i) {
13438      FieldDecl *FD = cast<FieldDecl>(*i);
13439  
13440      // Get the type for the field.
13441      const Type *FDTy = FD->getType().getTypePtr();
13442  
13443      if (!FD->isAnonymousStructOrUnion()) {
13444        // Remember all fields written by the user.
13445        RecFields.push_back(FD);
13446      }
13447  
13448      // If the field is already invalid for some reason, don't emit more
13449      // diagnostics about it.
13450      if (FD->isInvalidDecl()) {
13451        EnclosingDecl->setInvalidDecl();
13452        continue;
13453      }
13454  
13455      // C99 6.7.2.1p2:
13456      //   A structure or union shall not contain a member with
13457      //   incomplete or function type (hence, a structure shall not
13458      //   contain an instance of itself, but may contain a pointer to
13459      //   an instance of itself), except that the last member of a
13460      //   structure with more than one named member may have incomplete
13461      //   array type; such a structure (and any union containing,
13462      //   possibly recursively, a member that is such a structure)
13463      //   shall not be a member of a structure or an element of an
13464      //   array.
13465      if (FDTy->isFunctionType()) {
13466        // Field declared as a function.
13467        Diag(FD->getLocation(), diag::err_field_declared_as_function)
13468          << FD->getDeclName();
13469        FD->setInvalidDecl();
13470        EnclosingDecl->setInvalidDecl();
13471        continue;
13472      } else if (FDTy->isIncompleteArrayType() && Record &&
13473                 ((i + 1 == Fields.end() && !Record->isUnion()) ||
13474                  ((getLangOpts().MicrosoftExt ||
13475                    getLangOpts().CPlusPlus) &&
13476                   (i + 1 == Fields.end() || Record->isUnion())))) {
13477        // Flexible array member.
13478        // Microsoft and g++ is more permissive regarding flexible array.
13479        // It will accept flexible array in union and also
13480        // as the sole element of a struct/class.
13481        unsigned DiagID = 0;
13482        if (Record->isUnion())
13483          DiagID = getLangOpts().MicrosoftExt
13484                       ? diag::ext_flexible_array_union_ms
13485                       : getLangOpts().CPlusPlus
13486                             ? diag::ext_flexible_array_union_gnu
13487                             : diag::err_flexible_array_union;
13488        else if (Fields.size() == 1)
13489          DiagID = getLangOpts().MicrosoftExt
13490                       ? diag::ext_flexible_array_empty_aggregate_ms
13491                       : getLangOpts().CPlusPlus
13492                             ? diag::ext_flexible_array_empty_aggregate_gnu
13493                             : NumNamedMembers < 1
13494                                   ? diag::err_flexible_array_empty_aggregate
13495                                   : 0;
13496  
13497        if (DiagID)
13498          Diag(FD->getLocation(), DiagID) << FD->getDeclName()
13499                                          << Record->getTagKind();
13500        // While the layout of types that contain virtual bases is not specified
13501        // by the C++ standard, both the Itanium and Microsoft C++ ABIs place
13502        // virtual bases after the derived members.  This would make a flexible
13503        // array member declared at the end of an object not adjacent to the end
13504        // of the type.
13505        if (CXXRecordDecl *RD = dyn_cast<CXXRecordDecl>(Record))
13506          if (RD->getNumVBases() != 0)
13507            Diag(FD->getLocation(), diag::err_flexible_array_virtual_base)
13508              << FD->getDeclName() << Record->getTagKind();
13509        if (!getLangOpts().C99)
13510          Diag(FD->getLocation(), diag::ext_c99_flexible_array_member)
13511            << FD->getDeclName() << Record->getTagKind();
13512  
13513        // If the element type has a non-trivial destructor, we would not
13514        // implicitly destroy the elements, so disallow it for now.
13515        //
13516        // FIXME: GCC allows this. We should probably either implicitly delete
13517        // the destructor of the containing class, or just allow this.
13518        QualType BaseElem = Context.getBaseElementType(FD->getType());
13519        if (!BaseElem->isDependentType() && BaseElem.isDestructedType()) {
13520          Diag(FD->getLocation(), diag::err_flexible_array_has_nontrivial_dtor)
13521            << FD->getDeclName() << FD->getType();
13522          FD->setInvalidDecl();
13523          EnclosingDecl->setInvalidDecl();
13524          continue;
13525        }
13526        // Okay, we have a legal flexible array member at the end of the struct.
13527        Record->setHasFlexibleArrayMember(true);
13528      } else if (!FDTy->isDependentType() &&
13529                 RequireCompleteType(FD->getLocation(), FD->getType(),
13530                                     diag::err_field_incomplete)) {
13531        // Incomplete type
13532        FD->setInvalidDecl();
13533        EnclosingDecl->setInvalidDecl();
13534        continue;
13535      } else if (const RecordType *FDTTy = FDTy->getAs<RecordType>()) {
13536        if (Record && FDTTy->getDecl()->hasFlexibleArrayMember()) {
13537          // A type which contains a flexible array member is considered to be a
13538          // flexible array member.
13539          Record->setHasFlexibleArrayMember(true);
13540          if (!Record->isUnion()) {
13541            // If this is a struct/class and this is not the last element, reject
13542            // it.  Note that GCC supports variable sized arrays in the middle of
13543            // structures.
13544            if (i + 1 != Fields.end())
13545              Diag(FD->getLocation(), diag::ext_variable_sized_type_in_struct)
13546                << FD->getDeclName() << FD->getType();
13547            else {
13548              // We support flexible arrays at the end of structs in
13549              // other structs as an extension.
13550              Diag(FD->getLocation(), diag::ext_flexible_array_in_struct)
13551                << FD->getDeclName();
13552            }
13553          }
13554        }
13555        if (isa<ObjCContainerDecl>(EnclosingDecl) &&
13556            RequireNonAbstractType(FD->getLocation(), FD->getType(),
13557                                   diag::err_abstract_type_in_decl,
13558                                   AbstractIvarType)) {
13559          // Ivars can not have abstract class types
13560          FD->setInvalidDecl();
13561        }
13562        if (Record && FDTTy->getDecl()->hasObjectMember())
13563          Record->setHasObjectMember(true);
13564        if (Record && FDTTy->getDecl()->hasVolatileMember())
13565          Record->setHasVolatileMember(true);
13566      } else if (FDTy->isObjCObjectType()) {
13567        /// A field cannot be an Objective-c object
13568        Diag(FD->getLocation(), diag::err_statically_allocated_object)
13569          << FixItHint::CreateInsertion(FD->getLocation(), "*");
13570        QualType T = Context.getObjCObjectPointerType(FD->getType());
13571        FD->setType(T);
13572      } else if (getLangOpts().ObjCAutoRefCount && Record && !ARCErrReported &&
13573                 (!getLangOpts().CPlusPlus || Record->isUnion())) {
13574        // It's an error in ARC if a field has lifetime.
13575        // We don't want to report this in a system header, though,
13576        // so we just make the field unavailable.
13577        // FIXME: that's really not sufficient; we need to make the type
13578        // itself invalid to, say, initialize or copy.
13579        QualType T = FD->getType();
13580        Qualifiers::ObjCLifetime lifetime = T.getObjCLifetime();
13581        if (lifetime && lifetime != Qualifiers::OCL_ExplicitNone) {
13582          SourceLocation loc = FD->getLocation();
13583          if (getSourceManager().isInSystemHeader(loc)) {
13584            if (!FD->hasAttr<UnavailableAttr>()) {
13585              FD->addAttr(UnavailableAttr::CreateImplicit(Context, "",
13586                            UnavailableAttr::IR_ARCFieldWithOwnership, loc));
13587            }
13588          } else {
13589            Diag(FD->getLocation(), diag::err_arc_objc_object_in_tag)
13590              << T->isBlockPointerType() << Record->getTagKind();
13591          }
13592          ARCErrReported = true;
13593        }
13594      } else if (getLangOpts().ObjC1 &&
13595                 getLangOpts().getGC() != LangOptions::NonGC &&
13596                 Record && !Record->hasObjectMember()) {
13597        if (FD->getType()->isObjCObjectPointerType() ||
13598            FD->getType().isObjCGCStrong())
13599          Record->setHasObjectMember(true);
13600        else if (Context.getAsArrayType(FD->getType())) {
13601          QualType BaseType = Context.getBaseElementType(FD->getType());
13602          if (BaseType->isRecordType() &&
13603              BaseType->getAs<RecordType>()->getDecl()->hasObjectMember())
13604            Record->setHasObjectMember(true);
13605          else if (BaseType->isObjCObjectPointerType() ||
13606                   BaseType.isObjCGCStrong())
13607                 Record->setHasObjectMember(true);
13608        }
13609      }
13610      if (Record && FD->getType().isVolatileQualified())
13611        Record->setHasVolatileMember(true);
13612      // Keep track of the number of named members.
13613      if (FD->getIdentifier())
13614        ++NumNamedMembers;
13615    }
13616  
13617    // Okay, we successfully defined 'Record'.
13618    if (Record) {
13619      bool Completed = false;
13620      if (CXXRecordDecl *CXXRecord = dyn_cast<CXXRecordDecl>(Record)) {
13621        if (!CXXRecord->isInvalidDecl()) {
13622          // Set access bits correctly on the directly-declared conversions.
13623          for (CXXRecordDecl::conversion_iterator
13624                 I = CXXRecord->conversion_begin(),
13625                 E = CXXRecord->conversion_end(); I != E; ++I)
13626            I.setAccess((*I)->getAccess());
13627  
13628          if (!CXXRecord->isDependentType()) {
13629            if (CXXRecord->hasUserDeclaredDestructor()) {
13630              // Adjust user-defined destructor exception spec.
13631              if (getLangOpts().CPlusPlus11)
13632                AdjustDestructorExceptionSpec(CXXRecord,
13633                                              CXXRecord->getDestructor());
13634            }
13635  
13636            // Add any implicitly-declared members to this class.
13637            AddImplicitlyDeclaredMembersToClass(CXXRecord);
13638  
13639            // If we have virtual base classes, we may end up finding multiple
13640            // final overriders for a given virtual function. Check for this
13641            // problem now.
13642            if (CXXRecord->getNumVBases()) {
13643              CXXFinalOverriderMap FinalOverriders;
13644              CXXRecord->getFinalOverriders(FinalOverriders);
13645  
13646              for (CXXFinalOverriderMap::iterator M = FinalOverriders.begin(),
13647                                               MEnd = FinalOverriders.end();
13648                   M != MEnd; ++M) {
13649                for (OverridingMethods::iterator SO = M->second.begin(),
13650                                              SOEnd = M->second.end();
13651                     SO != SOEnd; ++SO) {
13652                  assert(SO->second.size() > 0 &&
13653                         "Virtual function without overridding functions?");
13654                  if (SO->second.size() == 1)
13655                    continue;
13656  
13657                  // C++ [class.virtual]p2:
13658                  //   In a derived class, if a virtual member function of a base
13659                  //   class subobject has more than one final overrider the
13660                  //   program is ill-formed.
13661                  Diag(Record->getLocation(), diag::err_multiple_final_overriders)
13662                    << (const NamedDecl *)M->first << Record;
13663                  Diag(M->first->getLocation(),
13664                       diag::note_overridden_virtual_function);
13665                  for (OverridingMethods::overriding_iterator
13666                            OM = SO->second.begin(),
13667                         OMEnd = SO->second.end();
13668                       OM != OMEnd; ++OM)
13669                    Diag(OM->Method->getLocation(), diag::note_final_overrider)
13670                      << (const NamedDecl *)M->first << OM->Method->getParent();
13671  
13672                  Record->setInvalidDecl();
13673                }
13674              }
13675              CXXRecord->completeDefinition(&FinalOverriders);
13676              Completed = true;
13677            }
13678          }
13679        }
13680      }
13681  
13682      if (!Completed)
13683        Record->completeDefinition();
13684  
13685      if (Record->hasAttrs()) {
13686        CheckAlignasUnderalignment(Record);
13687  
13688        if (const MSInheritanceAttr *IA = Record->getAttr<MSInheritanceAttr>())
13689          checkMSInheritanceAttrOnDefinition(cast<CXXRecordDecl>(Record),
13690                                             IA->getRange(), IA->getBestCase(),
13691                                             IA->getSemanticSpelling());
13692      }
13693  
13694      // Check if the structure/union declaration is a type that can have zero
13695      // size in C. For C this is a language extension, for C++ it may cause
13696      // compatibility problems.
13697      bool CheckForZeroSize;
13698      if (!getLangOpts().CPlusPlus) {
13699        CheckForZeroSize = true;
13700      } else {
13701        // For C++ filter out types that cannot be referenced in C code.
13702        CXXRecordDecl *CXXRecord = cast<CXXRecordDecl>(Record);
13703        CheckForZeroSize =
13704            CXXRecord->getLexicalDeclContext()->isExternCContext() &&
13705            !CXXRecord->isDependentType() &&
13706            CXXRecord->isCLike();
13707      }
13708      if (CheckForZeroSize) {
13709        bool ZeroSize = true;
13710        bool IsEmpty = true;
13711        unsigned NonBitFields = 0;
13712        for (RecordDecl::field_iterator I = Record->field_begin(),
13713                                        E = Record->field_end();
13714             (NonBitFields == 0 || ZeroSize) && I != E; ++I) {
13715          IsEmpty = false;
13716          if (I->isUnnamedBitfield()) {
13717            if (I->getBitWidthValue(Context) > 0)
13718              ZeroSize = false;
13719          } else {
13720            ++NonBitFields;
13721            QualType FieldType = I->getType();
13722            if (FieldType->isIncompleteType() ||
13723                !Context.getTypeSizeInChars(FieldType).isZero())
13724              ZeroSize = false;
13725          }
13726        }
13727  
13728        // Empty structs are an extension in C (C99 6.7.2.1p7). They are
13729        // allowed in C++, but warn if its declaration is inside
13730        // extern "C" block.
13731        if (ZeroSize) {
13732          Diag(RecLoc, getLangOpts().CPlusPlus ?
13733                           diag::warn_zero_size_struct_union_in_extern_c :
13734                           diag::warn_zero_size_struct_union_compat)
13735            << IsEmpty << Record->isUnion() << (NonBitFields > 1);
13736        }
13737  
13738        // Structs without named members are extension in C (C99 6.7.2.1p7),
13739        // but are accepted by GCC.
13740        if (NonBitFields == 0 && !getLangOpts().CPlusPlus) {
13741          Diag(RecLoc, IsEmpty ? diag::ext_empty_struct_union :
13742                                 diag::ext_no_named_members_in_struct_union)
13743            << Record->isUnion();
13744        }
13745      }
13746    } else {
13747      ObjCIvarDecl **ClsFields =
13748        reinterpret_cast<ObjCIvarDecl**>(RecFields.data());
13749      if (ObjCInterfaceDecl *ID = dyn_cast<ObjCInterfaceDecl>(EnclosingDecl)) {
13750        ID->setEndOfDefinitionLoc(RBrac);
13751        // Add ivar's to class's DeclContext.
13752        for (unsigned i = 0, e = RecFields.size(); i != e; ++i) {
13753          ClsFields[i]->setLexicalDeclContext(ID);
13754          ID->addDecl(ClsFields[i]);
13755        }
13756        // Must enforce the rule that ivars in the base classes may not be
13757        // duplicates.
13758        if (ID->getSuperClass())
13759          DiagnoseDuplicateIvars(ID, ID->getSuperClass());
13760      } else if (ObjCImplementationDecl *IMPDecl =
13761                    dyn_cast<ObjCImplementationDecl>(EnclosingDecl)) {
13762        assert(IMPDecl && "ActOnFields - missing ObjCImplementationDecl");
13763        for (unsigned I = 0, N = RecFields.size(); I != N; ++I)
13764          // Ivar declared in @implementation never belongs to the implementation.
13765          // Only it is in implementation's lexical context.
13766          ClsFields[I]->setLexicalDeclContext(IMPDecl);
13767        CheckImplementationIvars(IMPDecl, ClsFields, RecFields.size(), RBrac);
13768        IMPDecl->setIvarLBraceLoc(LBrac);
13769        IMPDecl->setIvarRBraceLoc(RBrac);
13770      } else if (ObjCCategoryDecl *CDecl =
13771                  dyn_cast<ObjCCategoryDecl>(EnclosingDecl)) {
13772        // case of ivars in class extension; all other cases have been
13773        // reported as errors elsewhere.
13774        // FIXME. Class extension does not have a LocEnd field.
13775        // CDecl->setLocEnd(RBrac);
13776        // Add ivar's to class extension's DeclContext.
13777        // Diagnose redeclaration of private ivars.
13778        ObjCInterfaceDecl *IDecl = CDecl->getClassInterface();
13779        for (unsigned i = 0, e = RecFields.size(); i != e; ++i) {
13780          if (IDecl) {
13781            if (const ObjCIvarDecl *ClsIvar =
13782                IDecl->getIvarDecl(ClsFields[i]->getIdentifier())) {
13783              Diag(ClsFields[i]->getLocation(),
13784                   diag::err_duplicate_ivar_declaration);
13785              Diag(ClsIvar->getLocation(), diag::note_previous_definition);
13786              continue;
13787            }
13788            for (const auto *Ext : IDecl->known_extensions()) {
13789              if (const ObjCIvarDecl *ClsExtIvar
13790                    = Ext->getIvarDecl(ClsFields[i]->getIdentifier())) {
13791                Diag(ClsFields[i]->getLocation(),
13792                     diag::err_duplicate_ivar_declaration);
13793                Diag(ClsExtIvar->getLocation(), diag::note_previous_definition);
13794                continue;
13795              }
13796            }
13797          }
13798          ClsFields[i]->setLexicalDeclContext(CDecl);
13799          CDecl->addDecl(ClsFields[i]);
13800        }
13801        CDecl->setIvarLBraceLoc(LBrac);
13802        CDecl->setIvarRBraceLoc(RBrac);
13803      }
13804    }
13805  
13806    if (Attr)
13807      ProcessDeclAttributeList(S, Record, Attr);
13808  }
13809  
13810  /// \brief Determine whether the given integral value is representable within
13811  /// the given type T.
isRepresentableIntegerValue(ASTContext & Context,llvm::APSInt & Value,QualType T)13812  static bool isRepresentableIntegerValue(ASTContext &Context,
13813                                          llvm::APSInt &Value,
13814                                          QualType T) {
13815    assert(T->isIntegralType(Context) && "Integral type required!");
13816    unsigned BitWidth = Context.getIntWidth(T);
13817  
13818    if (Value.isUnsigned() || Value.isNonNegative()) {
13819      if (T->isSignedIntegerOrEnumerationType())
13820        --BitWidth;
13821      return Value.getActiveBits() <= BitWidth;
13822    }
13823    return Value.getMinSignedBits() <= BitWidth;
13824  }
13825  
13826  // \brief Given an integral type, return the next larger integral type
13827  // (or a NULL type of no such type exists).
getNextLargerIntegralType(ASTContext & Context,QualType T)13828  static QualType getNextLargerIntegralType(ASTContext &Context, QualType T) {
13829    // FIXME: Int128/UInt128 support, which also needs to be introduced into
13830    // enum checking below.
13831    assert(T->isIntegralType(Context) && "Integral type required!");
13832    const unsigned NumTypes = 4;
13833    QualType SignedIntegralTypes[NumTypes] = {
13834      Context.ShortTy, Context.IntTy, Context.LongTy, Context.LongLongTy
13835    };
13836    QualType UnsignedIntegralTypes[NumTypes] = {
13837      Context.UnsignedShortTy, Context.UnsignedIntTy, Context.UnsignedLongTy,
13838      Context.UnsignedLongLongTy
13839    };
13840  
13841    unsigned BitWidth = Context.getTypeSize(T);
13842    QualType *Types = T->isSignedIntegerOrEnumerationType()? SignedIntegralTypes
13843                                                          : UnsignedIntegralTypes;
13844    for (unsigned I = 0; I != NumTypes; ++I)
13845      if (Context.getTypeSize(Types[I]) > BitWidth)
13846        return Types[I];
13847  
13848    return QualType();
13849  }
13850  
CheckEnumConstant(EnumDecl * Enum,EnumConstantDecl * LastEnumConst,SourceLocation IdLoc,IdentifierInfo * Id,Expr * Val)13851  EnumConstantDecl *Sema::CheckEnumConstant(EnumDecl *Enum,
13852                                            EnumConstantDecl *LastEnumConst,
13853                                            SourceLocation IdLoc,
13854                                            IdentifierInfo *Id,
13855                                            Expr *Val) {
13856    unsigned IntWidth = Context.getTargetInfo().getIntWidth();
13857    llvm::APSInt EnumVal(IntWidth);
13858    QualType EltTy;
13859  
13860    if (Val && DiagnoseUnexpandedParameterPack(Val, UPPC_EnumeratorValue))
13861      Val = nullptr;
13862  
13863    if (Val)
13864      Val = DefaultLvalueConversion(Val).get();
13865  
13866    if (Val) {
13867      if (Enum->isDependentType() || Val->isTypeDependent())
13868        EltTy = Context.DependentTy;
13869      else {
13870        SourceLocation ExpLoc;
13871        if (getLangOpts().CPlusPlus11 && Enum->isFixed() &&
13872            !getLangOpts().MSVCCompat) {
13873          // C++11 [dcl.enum]p5: If the underlying type is fixed, [...] the
13874          // constant-expression in the enumerator-definition shall be a converted
13875          // constant expression of the underlying type.
13876          EltTy = Enum->getIntegerType();
13877          ExprResult Converted =
13878            CheckConvertedConstantExpression(Val, EltTy, EnumVal,
13879                                             CCEK_Enumerator);
13880          if (Converted.isInvalid())
13881            Val = nullptr;
13882          else
13883            Val = Converted.get();
13884        } else if (!Val->isValueDependent() &&
13885                   !(Val = VerifyIntegerConstantExpression(Val,
13886                                                           &EnumVal).get())) {
13887          // C99 6.7.2.2p2: Make sure we have an integer constant expression.
13888        } else {
13889          if (Enum->isFixed()) {
13890            EltTy = Enum->getIntegerType();
13891  
13892            // In Obj-C and Microsoft mode, require the enumeration value to be
13893            // representable in the underlying type of the enumeration. In C++11,
13894            // we perform a non-narrowing conversion as part of converted constant
13895            // expression checking.
13896            if (!isRepresentableIntegerValue(Context, EnumVal, EltTy)) {
13897              if (getLangOpts().MSVCCompat) {
13898                Diag(IdLoc, diag::ext_enumerator_too_large) << EltTy;
13899                Val = ImpCastExprToType(Val, EltTy, CK_IntegralCast).get();
13900              } else
13901                Diag(IdLoc, diag::err_enumerator_too_large) << EltTy;
13902            } else
13903              Val = ImpCastExprToType(Val, EltTy, CK_IntegralCast).get();
13904          } else if (getLangOpts().CPlusPlus) {
13905            // C++11 [dcl.enum]p5:
13906            //   If the underlying type is not fixed, the type of each enumerator
13907            //   is the type of its initializing value:
13908            //     - If an initializer is specified for an enumerator, the
13909            //       initializing value has the same type as the expression.
13910            EltTy = Val->getType();
13911          } else {
13912            // C99 6.7.2.2p2:
13913            //   The expression that defines the value of an enumeration constant
13914            //   shall be an integer constant expression that has a value
13915            //   representable as an int.
13916  
13917            // Complain if the value is not representable in an int.
13918            if (!isRepresentableIntegerValue(Context, EnumVal, Context.IntTy))
13919              Diag(IdLoc, diag::ext_enum_value_not_int)
13920                << EnumVal.toString(10) << Val->getSourceRange()
13921                << (EnumVal.isUnsigned() || EnumVal.isNonNegative());
13922            else if (!Context.hasSameType(Val->getType(), Context.IntTy)) {
13923              // Force the type of the expression to 'int'.
13924              Val = ImpCastExprToType(Val, Context.IntTy, CK_IntegralCast).get();
13925            }
13926            EltTy = Val->getType();
13927          }
13928        }
13929      }
13930    }
13931  
13932    if (!Val) {
13933      if (Enum->isDependentType())
13934        EltTy = Context.DependentTy;
13935      else if (!LastEnumConst) {
13936        // C++0x [dcl.enum]p5:
13937        //   If the underlying type is not fixed, the type of each enumerator
13938        //   is the type of its initializing value:
13939        //     - If no initializer is specified for the first enumerator, the
13940        //       initializing value has an unspecified integral type.
13941        //
13942        // GCC uses 'int' for its unspecified integral type, as does
13943        // C99 6.7.2.2p3.
13944        if (Enum->isFixed()) {
13945          EltTy = Enum->getIntegerType();
13946        }
13947        else {
13948          EltTy = Context.IntTy;
13949        }
13950      } else {
13951        // Assign the last value + 1.
13952        EnumVal = LastEnumConst->getInitVal();
13953        ++EnumVal;
13954        EltTy = LastEnumConst->getType();
13955  
13956        // Check for overflow on increment.
13957        if (EnumVal < LastEnumConst->getInitVal()) {
13958          // C++0x [dcl.enum]p5:
13959          //   If the underlying type is not fixed, the type of each enumerator
13960          //   is the type of its initializing value:
13961          //
13962          //     - Otherwise the type of the initializing value is the same as
13963          //       the type of the initializing value of the preceding enumerator
13964          //       unless the incremented value is not representable in that type,
13965          //       in which case the type is an unspecified integral type
13966          //       sufficient to contain the incremented value. If no such type
13967          //       exists, the program is ill-formed.
13968          QualType T = getNextLargerIntegralType(Context, EltTy);
13969          if (T.isNull() || Enum->isFixed()) {
13970            // There is no integral type larger enough to represent this
13971            // value. Complain, then allow the value to wrap around.
13972            EnumVal = LastEnumConst->getInitVal();
13973            EnumVal = EnumVal.zext(EnumVal.getBitWidth() * 2);
13974            ++EnumVal;
13975            if (Enum->isFixed())
13976              // When the underlying type is fixed, this is ill-formed.
13977              Diag(IdLoc, diag::err_enumerator_wrapped)
13978                << EnumVal.toString(10)
13979                << EltTy;
13980            else
13981              Diag(IdLoc, diag::ext_enumerator_increment_too_large)
13982                << EnumVal.toString(10);
13983          } else {
13984            EltTy = T;
13985          }
13986  
13987          // Retrieve the last enumerator's value, extent that type to the
13988          // type that is supposed to be large enough to represent the incremented
13989          // value, then increment.
13990          EnumVal = LastEnumConst->getInitVal();
13991          EnumVal.setIsSigned(EltTy->isSignedIntegerOrEnumerationType());
13992          EnumVal = EnumVal.zextOrTrunc(Context.getIntWidth(EltTy));
13993          ++EnumVal;
13994  
13995          // If we're not in C++, diagnose the overflow of enumerator values,
13996          // which in C99 means that the enumerator value is not representable in
13997          // an int (C99 6.7.2.2p2). However, we support GCC's extension that
13998          // permits enumerator values that are representable in some larger
13999          // integral type.
14000          if (!getLangOpts().CPlusPlus && !T.isNull())
14001            Diag(IdLoc, diag::warn_enum_value_overflow);
14002        } else if (!getLangOpts().CPlusPlus &&
14003                   !isRepresentableIntegerValue(Context, EnumVal, EltTy)) {
14004          // Enforce C99 6.7.2.2p2 even when we compute the next value.
14005          Diag(IdLoc, diag::ext_enum_value_not_int)
14006            << EnumVal.toString(10) << 1;
14007        }
14008      }
14009    }
14010  
14011    if (!EltTy->isDependentType()) {
14012      // Make the enumerator value match the signedness and size of the
14013      // enumerator's type.
14014      EnumVal = EnumVal.extOrTrunc(Context.getIntWidth(EltTy));
14015      EnumVal.setIsSigned(EltTy->isSignedIntegerOrEnumerationType());
14016    }
14017  
14018    return EnumConstantDecl::Create(Context, Enum, IdLoc, Id, EltTy,
14019                                    Val, EnumVal);
14020  }
14021  
shouldSkipAnonEnumBody(Scope * S,IdentifierInfo * II,SourceLocation IILoc)14022  Sema::SkipBodyInfo Sema::shouldSkipAnonEnumBody(Scope *S, IdentifierInfo *II,
14023                                                  SourceLocation IILoc) {
14024    if (!(getLangOpts().Modules || getLangOpts().ModulesLocalVisibility) ||
14025        !getLangOpts().CPlusPlus)
14026      return SkipBodyInfo();
14027  
14028    // We have an anonymous enum definition. Look up the first enumerator to
14029    // determine if we should merge the definition with an existing one and
14030    // skip the body.
14031    NamedDecl *PrevDecl = LookupSingleName(S, II, IILoc, LookupOrdinaryName,
14032                                           ForRedeclaration);
14033    auto *PrevECD = dyn_cast_or_null<EnumConstantDecl>(PrevDecl);
14034    if (!PrevECD)
14035      return SkipBodyInfo();
14036  
14037    EnumDecl *PrevED = cast<EnumDecl>(PrevECD->getDeclContext());
14038    NamedDecl *Hidden;
14039    if (!PrevED->getDeclName() && !hasVisibleDefinition(PrevED, &Hidden)) {
14040      SkipBodyInfo Skip;
14041      Skip.Previous = Hidden;
14042      return Skip;
14043    }
14044  
14045    return SkipBodyInfo();
14046  }
14047  
ActOnEnumConstant(Scope * S,Decl * theEnumDecl,Decl * lastEnumConst,SourceLocation IdLoc,IdentifierInfo * Id,AttributeList * Attr,SourceLocation EqualLoc,Expr * Val)14048  Decl *Sema::ActOnEnumConstant(Scope *S, Decl *theEnumDecl, Decl *lastEnumConst,
14049                                SourceLocation IdLoc, IdentifierInfo *Id,
14050                                AttributeList *Attr,
14051                                SourceLocation EqualLoc, Expr *Val) {
14052    EnumDecl *TheEnumDecl = cast<EnumDecl>(theEnumDecl);
14053    EnumConstantDecl *LastEnumConst =
14054      cast_or_null<EnumConstantDecl>(lastEnumConst);
14055  
14056    // The scope passed in may not be a decl scope.  Zip up the scope tree until
14057    // we find one that is.
14058    S = getNonFieldDeclScope(S);
14059  
14060    // Verify that there isn't already something declared with this name in this
14061    // scope.
14062    NamedDecl *PrevDecl = LookupSingleName(S, Id, IdLoc, LookupOrdinaryName,
14063                                           ForRedeclaration);
14064    if (PrevDecl && PrevDecl->isTemplateParameter()) {
14065      // Maybe we will complain about the shadowed template parameter.
14066      DiagnoseTemplateParameterShadow(IdLoc, PrevDecl);
14067      // Just pretend that we didn't see the previous declaration.
14068      PrevDecl = nullptr;
14069    }
14070  
14071    // C++ [class.mem]p15:
14072    // If T is the name of a class, then each of the following shall have a name
14073    // different from T:
14074    // - every enumerator of every member of class T that is an unscoped
14075    // enumerated type
14076    if (!TheEnumDecl->isScoped())
14077      DiagnoseClassNameShadow(TheEnumDecl->getDeclContext(),
14078                              DeclarationNameInfo(Id, IdLoc));
14079  
14080    EnumConstantDecl *New =
14081      CheckEnumConstant(TheEnumDecl, LastEnumConst, IdLoc, Id, Val);
14082    if (!New)
14083      return nullptr;
14084  
14085    if (PrevDecl) {
14086      // When in C++, we may get a TagDecl with the same name; in this case the
14087      // enum constant will 'hide' the tag.
14088      assert((getLangOpts().CPlusPlus || !isa<TagDecl>(PrevDecl)) &&
14089             "Received TagDecl when not in C++!");
14090      if (!isa<TagDecl>(PrevDecl) && isDeclInScope(PrevDecl, CurContext, S) &&
14091          shouldLinkPossiblyHiddenDecl(PrevDecl, New)) {
14092        if (isa<EnumConstantDecl>(PrevDecl))
14093          Diag(IdLoc, diag::err_redefinition_of_enumerator) << Id;
14094        else
14095          Diag(IdLoc, diag::err_redefinition) << Id;
14096        Diag(PrevDecl->getLocation(), diag::note_previous_definition);
14097        return nullptr;
14098      }
14099    }
14100  
14101    // Process attributes.
14102    if (Attr) ProcessDeclAttributeList(S, New, Attr);
14103  
14104    // Register this decl in the current scope stack.
14105    New->setAccess(TheEnumDecl->getAccess());
14106    PushOnScopeChains(New, S);
14107  
14108    ActOnDocumentableDecl(New);
14109  
14110    return New;
14111  }
14112  
14113  // Returns true when the enum initial expression does not trigger the
14114  // duplicate enum warning.  A few common cases are exempted as follows:
14115  // Element2 = Element1
14116  // Element2 = Element1 + 1
14117  // Element2 = Element1 - 1
14118  // Where Element2 and Element1 are from the same enum.
ValidDuplicateEnum(EnumConstantDecl * ECD,EnumDecl * Enum)14119  static bool ValidDuplicateEnum(EnumConstantDecl *ECD, EnumDecl *Enum) {
14120    Expr *InitExpr = ECD->getInitExpr();
14121    if (!InitExpr)
14122      return true;
14123    InitExpr = InitExpr->IgnoreImpCasts();
14124  
14125    if (BinaryOperator *BO = dyn_cast<BinaryOperator>(InitExpr)) {
14126      if (!BO->isAdditiveOp())
14127        return true;
14128      IntegerLiteral *IL = dyn_cast<IntegerLiteral>(BO->getRHS());
14129      if (!IL)
14130        return true;
14131      if (IL->getValue() != 1)
14132        return true;
14133  
14134      InitExpr = BO->getLHS();
14135    }
14136  
14137    // This checks if the elements are from the same enum.
14138    DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(InitExpr);
14139    if (!DRE)
14140      return true;
14141  
14142    EnumConstantDecl *EnumConstant = dyn_cast<EnumConstantDecl>(DRE->getDecl());
14143    if (!EnumConstant)
14144      return true;
14145  
14146    if (cast<EnumDecl>(TagDecl::castFromDeclContext(ECD->getDeclContext())) !=
14147        Enum)
14148      return true;
14149  
14150    return false;
14151  }
14152  
14153  namespace {
14154  struct DupKey {
14155    int64_t val;
14156    bool isTombstoneOrEmptyKey;
DupKey__anon7cb36e300b11::DupKey14157    DupKey(int64_t val, bool isTombstoneOrEmptyKey)
14158      : val(val), isTombstoneOrEmptyKey(isTombstoneOrEmptyKey) {}
14159  };
14160  
GetDupKey(const llvm::APSInt & Val)14161  static DupKey GetDupKey(const llvm::APSInt& Val) {
14162    return DupKey(Val.isSigned() ? Val.getSExtValue() : Val.getZExtValue(),
14163                  false);
14164  }
14165  
14166  struct DenseMapInfoDupKey {
getEmptyKey__anon7cb36e300b11::DenseMapInfoDupKey14167    static DupKey getEmptyKey() { return DupKey(0, true); }
getTombstoneKey__anon7cb36e300b11::DenseMapInfoDupKey14168    static DupKey getTombstoneKey() { return DupKey(1, true); }
getHashValue__anon7cb36e300b11::DenseMapInfoDupKey14169    static unsigned getHashValue(const DupKey Key) {
14170      return (unsigned)(Key.val * 37);
14171    }
isEqual__anon7cb36e300b11::DenseMapInfoDupKey14172    static bool isEqual(const DupKey& LHS, const DupKey& RHS) {
14173      return LHS.isTombstoneOrEmptyKey == RHS.isTombstoneOrEmptyKey &&
14174             LHS.val == RHS.val;
14175    }
14176  };
14177  } // end anonymous namespace
14178  
14179  // Emits a warning when an element is implicitly set a value that
14180  // a previous element has already been set to.
CheckForDuplicateEnumValues(Sema & S,ArrayRef<Decl * > Elements,EnumDecl * Enum,QualType EnumType)14181  static void CheckForDuplicateEnumValues(Sema &S, ArrayRef<Decl *> Elements,
14182                                          EnumDecl *Enum,
14183                                          QualType EnumType) {
14184    if (S.Diags.isIgnored(diag::warn_duplicate_enum_values, Enum->getLocation()))
14185      return;
14186    // Avoid anonymous enums
14187    if (!Enum->getIdentifier())
14188      return;
14189  
14190    // Only check for small enums.
14191    if (Enum->getNumPositiveBits() > 63 || Enum->getNumNegativeBits() > 64)
14192      return;
14193  
14194    typedef SmallVector<EnumConstantDecl *, 3> ECDVector;
14195    typedef SmallVector<ECDVector *, 3> DuplicatesVector;
14196  
14197    typedef llvm::PointerUnion<EnumConstantDecl*, ECDVector*> DeclOrVector;
14198    typedef llvm::DenseMap<DupKey, DeclOrVector, DenseMapInfoDupKey>
14199            ValueToVectorMap;
14200  
14201    DuplicatesVector DupVector;
14202    ValueToVectorMap EnumMap;
14203  
14204    // Populate the EnumMap with all values represented by enum constants without
14205    // an initialier.
14206    for (unsigned i = 0, e = Elements.size(); i != e; ++i) {
14207      EnumConstantDecl *ECD = cast_or_null<EnumConstantDecl>(Elements[i]);
14208  
14209      // Null EnumConstantDecl means a previous diagnostic has been emitted for
14210      // this constant.  Skip this enum since it may be ill-formed.
14211      if (!ECD) {
14212        return;
14213      }
14214  
14215      if (ECD->getInitExpr())
14216        continue;
14217  
14218      DupKey Key = GetDupKey(ECD->getInitVal());
14219      DeclOrVector &Entry = EnumMap[Key];
14220  
14221      // First time encountering this value.
14222      if (Entry.isNull())
14223        Entry = ECD;
14224    }
14225  
14226    // Create vectors for any values that has duplicates.
14227    for (unsigned i = 0, e = Elements.size(); i != e; ++i) {
14228      EnumConstantDecl *ECD = cast<EnumConstantDecl>(Elements[i]);
14229      if (!ValidDuplicateEnum(ECD, Enum))
14230        continue;
14231  
14232      DupKey Key = GetDupKey(ECD->getInitVal());
14233  
14234      DeclOrVector& Entry = EnumMap[Key];
14235      if (Entry.isNull())
14236        continue;
14237  
14238      if (EnumConstantDecl *D = Entry.dyn_cast<EnumConstantDecl*>()) {
14239        // Ensure constants are different.
14240        if (D == ECD)
14241          continue;
14242  
14243        // Create new vector and push values onto it.
14244        ECDVector *Vec = new ECDVector();
14245        Vec->push_back(D);
14246        Vec->push_back(ECD);
14247  
14248        // Update entry to point to the duplicates vector.
14249        Entry = Vec;
14250  
14251        // Store the vector somewhere we can consult later for quick emission of
14252        // diagnostics.
14253        DupVector.push_back(Vec);
14254        continue;
14255      }
14256  
14257      ECDVector *Vec = Entry.get<ECDVector*>();
14258      // Make sure constants are not added more than once.
14259      if (*Vec->begin() == ECD)
14260        continue;
14261  
14262      Vec->push_back(ECD);
14263    }
14264  
14265    // Emit diagnostics.
14266    for (DuplicatesVector::iterator DupVectorIter = DupVector.begin(),
14267                                    DupVectorEnd = DupVector.end();
14268         DupVectorIter != DupVectorEnd; ++DupVectorIter) {
14269      ECDVector *Vec = *DupVectorIter;
14270      assert(Vec->size() > 1 && "ECDVector should have at least 2 elements.");
14271  
14272      // Emit warning for one enum constant.
14273      ECDVector::iterator I = Vec->begin();
14274      S.Diag((*I)->getLocation(), diag::warn_duplicate_enum_values)
14275        << (*I)->getName() << (*I)->getInitVal().toString(10)
14276        << (*I)->getSourceRange();
14277      ++I;
14278  
14279      // Emit one note for each of the remaining enum constants with
14280      // the same value.
14281      for (ECDVector::iterator E = Vec->end(); I != E; ++I)
14282        S.Diag((*I)->getLocation(), diag::note_duplicate_element)
14283          << (*I)->getName() << (*I)->getInitVal().toString(10)
14284          << (*I)->getSourceRange();
14285      delete Vec;
14286    }
14287  }
14288  
IsValueInFlagEnum(const EnumDecl * ED,const llvm::APInt & Val,bool AllowMask) const14289  bool Sema::IsValueInFlagEnum(const EnumDecl *ED, const llvm::APInt &Val,
14290                               bool AllowMask) const {
14291    assert(ED->hasAttr<FlagEnumAttr>() && "looking for value in non-flag enum");
14292    assert(ED->isCompleteDefinition() && "expected enum definition");
14293  
14294    auto R = FlagBitsCache.insert(std::make_pair(ED, llvm::APInt()));
14295    llvm::APInt &FlagBits = R.first->second;
14296  
14297    if (R.second) {
14298      for (auto *E : ED->enumerators()) {
14299        const auto &EVal = E->getInitVal();
14300        // Only single-bit enumerators introduce new flag values.
14301        if (EVal.isPowerOf2())
14302          FlagBits = FlagBits.zextOrSelf(EVal.getBitWidth()) | EVal;
14303      }
14304    }
14305  
14306    // A value is in a flag enum if either its bits are a subset of the enum's
14307    // flag bits (the first condition) or we are allowing masks and the same is
14308    // true of its complement (the second condition). When masks are allowed, we
14309    // allow the common idiom of ~(enum1 | enum2) to be a valid enum value.
14310    //
14311    // While it's true that any value could be used as a mask, the assumption is
14312    // that a mask will have all of the insignificant bits set. Anything else is
14313    // likely a logic error.
14314    llvm::APInt FlagMask = ~FlagBits.zextOrTrunc(Val.getBitWidth());
14315    return !(FlagMask & Val) || (AllowMask && !(FlagMask & ~Val));
14316  }
14317  
ActOnEnumBody(SourceLocation EnumLoc,SourceLocation LBraceLoc,SourceLocation RBraceLoc,Decl * EnumDeclX,ArrayRef<Decl * > Elements,Scope * S,AttributeList * Attr)14318  void Sema::ActOnEnumBody(SourceLocation EnumLoc, SourceLocation LBraceLoc,
14319                           SourceLocation RBraceLoc, Decl *EnumDeclX,
14320                           ArrayRef<Decl *> Elements,
14321                           Scope *S, AttributeList *Attr) {
14322    EnumDecl *Enum = cast<EnumDecl>(EnumDeclX);
14323    QualType EnumType = Context.getTypeDeclType(Enum);
14324  
14325    if (Attr)
14326      ProcessDeclAttributeList(S, Enum, Attr);
14327  
14328    if (Enum->isDependentType()) {
14329      for (unsigned i = 0, e = Elements.size(); i != e; ++i) {
14330        EnumConstantDecl *ECD =
14331          cast_or_null<EnumConstantDecl>(Elements[i]);
14332        if (!ECD) continue;
14333  
14334        ECD->setType(EnumType);
14335      }
14336  
14337      Enum->completeDefinition(Context.DependentTy, Context.DependentTy, 0, 0);
14338      return;
14339    }
14340  
14341    // TODO: If the result value doesn't fit in an int, it must be a long or long
14342    // long value.  ISO C does not support this, but GCC does as an extension,
14343    // emit a warning.
14344    unsigned IntWidth = Context.getTargetInfo().getIntWidth();
14345    unsigned CharWidth = Context.getTargetInfo().getCharWidth();
14346    unsigned ShortWidth = Context.getTargetInfo().getShortWidth();
14347  
14348    // Verify that all the values are okay, compute the size of the values, and
14349    // reverse the list.
14350    unsigned NumNegativeBits = 0;
14351    unsigned NumPositiveBits = 0;
14352  
14353    // Keep track of whether all elements have type int.
14354    bool AllElementsInt = true;
14355  
14356    for (unsigned i = 0, e = Elements.size(); i != e; ++i) {
14357      EnumConstantDecl *ECD =
14358        cast_or_null<EnumConstantDecl>(Elements[i]);
14359      if (!ECD) continue;  // Already issued a diagnostic.
14360  
14361      const llvm::APSInt &InitVal = ECD->getInitVal();
14362  
14363      // Keep track of the size of positive and negative values.
14364      if (InitVal.isUnsigned() || InitVal.isNonNegative())
14365        NumPositiveBits = std::max(NumPositiveBits,
14366                                   (unsigned)InitVal.getActiveBits());
14367      else
14368        NumNegativeBits = std::max(NumNegativeBits,
14369                                   (unsigned)InitVal.getMinSignedBits());
14370  
14371      // Keep track of whether every enum element has type int (very commmon).
14372      if (AllElementsInt)
14373        AllElementsInt = ECD->getType() == Context.IntTy;
14374    }
14375  
14376    // Figure out the type that should be used for this enum.
14377    QualType BestType;
14378    unsigned BestWidth;
14379  
14380    // C++0x N3000 [conv.prom]p3:
14381    //   An rvalue of an unscoped enumeration type whose underlying
14382    //   type is not fixed can be converted to an rvalue of the first
14383    //   of the following types that can represent all the values of
14384    //   the enumeration: int, unsigned int, long int, unsigned long
14385    //   int, long long int, or unsigned long long int.
14386    // C99 6.4.4.3p2:
14387    //   An identifier declared as an enumeration constant has type int.
14388    // The C99 rule is modified by a gcc extension
14389    QualType BestPromotionType;
14390  
14391    bool Packed = Enum->hasAttr<PackedAttr>();
14392    // -fshort-enums is the equivalent to specifying the packed attribute on all
14393    // enum definitions.
14394    if (LangOpts.ShortEnums)
14395      Packed = true;
14396  
14397    if (Enum->isFixed()) {
14398      BestType = Enum->getIntegerType();
14399      if (BestType->isPromotableIntegerType())
14400        BestPromotionType = Context.getPromotedIntegerType(BestType);
14401      else
14402        BestPromotionType = BestType;
14403  
14404      BestWidth = Context.getIntWidth(BestType);
14405    }
14406    else if (NumNegativeBits) {
14407      // If there is a negative value, figure out the smallest integer type (of
14408      // int/long/longlong) that fits.
14409      // If it's packed, check also if it fits a char or a short.
14410      if (Packed && NumNegativeBits <= CharWidth && NumPositiveBits < CharWidth) {
14411        BestType = Context.SignedCharTy;
14412        BestWidth = CharWidth;
14413      } else if (Packed && NumNegativeBits <= ShortWidth &&
14414                 NumPositiveBits < ShortWidth) {
14415        BestType = Context.ShortTy;
14416        BestWidth = ShortWidth;
14417      } else if (NumNegativeBits <= IntWidth && NumPositiveBits < IntWidth) {
14418        BestType = Context.IntTy;
14419        BestWidth = IntWidth;
14420      } else {
14421        BestWidth = Context.getTargetInfo().getLongWidth();
14422  
14423        if (NumNegativeBits <= BestWidth && NumPositiveBits < BestWidth) {
14424          BestType = Context.LongTy;
14425        } else {
14426          BestWidth = Context.getTargetInfo().getLongLongWidth();
14427  
14428          if (NumNegativeBits > BestWidth || NumPositiveBits >= BestWidth)
14429            Diag(Enum->getLocation(), diag::ext_enum_too_large);
14430          BestType = Context.LongLongTy;
14431        }
14432      }
14433      BestPromotionType = (BestWidth <= IntWidth ? Context.IntTy : BestType);
14434    } else {
14435      // If there is no negative value, figure out the smallest type that fits
14436      // all of the enumerator values.
14437      // If it's packed, check also if it fits a char or a short.
14438      if (Packed && NumPositiveBits <= CharWidth) {
14439        BestType = Context.UnsignedCharTy;
14440        BestPromotionType = Context.IntTy;
14441        BestWidth = CharWidth;
14442      } else if (Packed && NumPositiveBits <= ShortWidth) {
14443        BestType = Context.UnsignedShortTy;
14444        BestPromotionType = Context.IntTy;
14445        BestWidth = ShortWidth;
14446      } else if (NumPositiveBits <= IntWidth) {
14447        BestType = Context.UnsignedIntTy;
14448        BestWidth = IntWidth;
14449        BestPromotionType
14450          = (NumPositiveBits == BestWidth || !getLangOpts().CPlusPlus)
14451                             ? Context.UnsignedIntTy : Context.IntTy;
14452      } else if (NumPositiveBits <=
14453                 (BestWidth = Context.getTargetInfo().getLongWidth())) {
14454        BestType = Context.UnsignedLongTy;
14455        BestPromotionType
14456          = (NumPositiveBits == BestWidth || !getLangOpts().CPlusPlus)
14457                             ? Context.UnsignedLongTy : Context.LongTy;
14458      } else {
14459        BestWidth = Context.getTargetInfo().getLongLongWidth();
14460        assert(NumPositiveBits <= BestWidth &&
14461               "How could an initializer get larger than ULL?");
14462        BestType = Context.UnsignedLongLongTy;
14463        BestPromotionType
14464          = (NumPositiveBits == BestWidth || !getLangOpts().CPlusPlus)
14465                             ? Context.UnsignedLongLongTy : Context.LongLongTy;
14466      }
14467    }
14468  
14469    // Loop over all of the enumerator constants, changing their types to match
14470    // the type of the enum if needed.
14471    for (auto *D : Elements) {
14472      auto *ECD = cast_or_null<EnumConstantDecl>(D);
14473      if (!ECD) continue;  // Already issued a diagnostic.
14474  
14475      // Standard C says the enumerators have int type, but we allow, as an
14476      // extension, the enumerators to be larger than int size.  If each
14477      // enumerator value fits in an int, type it as an int, otherwise type it the
14478      // same as the enumerator decl itself.  This means that in "enum { X = 1U }"
14479      // that X has type 'int', not 'unsigned'.
14480  
14481      // Determine whether the value fits into an int.
14482      llvm::APSInt InitVal = ECD->getInitVal();
14483  
14484      // If it fits into an integer type, force it.  Otherwise force it to match
14485      // the enum decl type.
14486      QualType NewTy;
14487      unsigned NewWidth;
14488      bool NewSign;
14489      if (!getLangOpts().CPlusPlus &&
14490          !Enum->isFixed() &&
14491          isRepresentableIntegerValue(Context, InitVal, Context.IntTy)) {
14492        NewTy = Context.IntTy;
14493        NewWidth = IntWidth;
14494        NewSign = true;
14495      } else if (ECD->getType() == BestType) {
14496        // Already the right type!
14497        if (getLangOpts().CPlusPlus)
14498          // C++ [dcl.enum]p4: Following the closing brace of an
14499          // enum-specifier, each enumerator has the type of its
14500          // enumeration.
14501          ECD->setType(EnumType);
14502        continue;
14503      } else {
14504        NewTy = BestType;
14505        NewWidth = BestWidth;
14506        NewSign = BestType->isSignedIntegerOrEnumerationType();
14507      }
14508  
14509      // Adjust the APSInt value.
14510      InitVal = InitVal.extOrTrunc(NewWidth);
14511      InitVal.setIsSigned(NewSign);
14512      ECD->setInitVal(InitVal);
14513  
14514      // Adjust the Expr initializer and type.
14515      if (ECD->getInitExpr() &&
14516          !Context.hasSameType(NewTy, ECD->getInitExpr()->getType()))
14517        ECD->setInitExpr(ImplicitCastExpr::Create(Context, NewTy,
14518                                                  CK_IntegralCast,
14519                                                  ECD->getInitExpr(),
14520                                                  /*base paths*/ nullptr,
14521                                                  VK_RValue));
14522      if (getLangOpts().CPlusPlus)
14523        // C++ [dcl.enum]p4: Following the closing brace of an
14524        // enum-specifier, each enumerator has the type of its
14525        // enumeration.
14526        ECD->setType(EnumType);
14527      else
14528        ECD->setType(NewTy);
14529    }
14530  
14531    Enum->completeDefinition(BestType, BestPromotionType,
14532                             NumPositiveBits, NumNegativeBits);
14533  
14534    CheckForDuplicateEnumValues(*this, Elements, Enum, EnumType);
14535  
14536    if (Enum->hasAttr<FlagEnumAttr>()) {
14537      for (Decl *D : Elements) {
14538        EnumConstantDecl *ECD = cast_or_null<EnumConstantDecl>(D);
14539        if (!ECD) continue;  // Already issued a diagnostic.
14540  
14541        llvm::APSInt InitVal = ECD->getInitVal();
14542        if (InitVal != 0 && !InitVal.isPowerOf2() &&
14543            !IsValueInFlagEnum(Enum, InitVal, true))
14544          Diag(ECD->getLocation(), diag::warn_flag_enum_constant_out_of_range)
14545            << ECD << Enum;
14546      }
14547    }
14548  
14549    // Now that the enum type is defined, ensure it's not been underaligned.
14550    if (Enum->hasAttrs())
14551      CheckAlignasUnderalignment(Enum);
14552  }
14553  
ActOnFileScopeAsmDecl(Expr * expr,SourceLocation StartLoc,SourceLocation EndLoc)14554  Decl *Sema::ActOnFileScopeAsmDecl(Expr *expr,
14555                                    SourceLocation StartLoc,
14556                                    SourceLocation EndLoc) {
14557    StringLiteral *AsmString = cast<StringLiteral>(expr);
14558  
14559    FileScopeAsmDecl *New = FileScopeAsmDecl::Create(Context, CurContext,
14560                                                     AsmString, StartLoc,
14561                                                     EndLoc);
14562    CurContext->addDecl(New);
14563    return New;
14564  }
14565  
checkModuleImportContext(Sema & S,Module * M,SourceLocation ImportLoc,DeclContext * DC,bool FromInclude=false)14566  static void checkModuleImportContext(Sema &S, Module *M,
14567                                       SourceLocation ImportLoc, DeclContext *DC,
14568                                       bool FromInclude = false) {
14569    SourceLocation ExternCLoc;
14570  
14571    if (auto *LSD = dyn_cast<LinkageSpecDecl>(DC)) {
14572      switch (LSD->getLanguage()) {
14573      case LinkageSpecDecl::lang_c:
14574        if (ExternCLoc.isInvalid())
14575          ExternCLoc = LSD->getLocStart();
14576        break;
14577      case LinkageSpecDecl::lang_cxx:
14578        break;
14579      }
14580      DC = LSD->getParent();
14581    }
14582  
14583    while (isa<LinkageSpecDecl>(DC))
14584      DC = DC->getParent();
14585  
14586    if (!isa<TranslationUnitDecl>(DC)) {
14587      S.Diag(ImportLoc, (FromInclude && S.isModuleVisible(M))
14588                            ? diag::ext_module_import_not_at_top_level_noop
14589                            : diag::err_module_import_not_at_top_level_fatal)
14590          << M->getFullModuleName() << DC;
14591      S.Diag(cast<Decl>(DC)->getLocStart(),
14592             diag::note_module_import_not_at_top_level) << DC;
14593    } else if (!M->IsExternC && ExternCLoc.isValid()) {
14594      S.Diag(ImportLoc, diag::ext_module_import_in_extern_c)
14595        << M->getFullModuleName();
14596      S.Diag(ExternCLoc, diag::note_module_import_in_extern_c);
14597    }
14598  }
14599  
diagnoseMisplacedModuleImport(Module * M,SourceLocation ImportLoc)14600  void Sema::diagnoseMisplacedModuleImport(Module *M, SourceLocation ImportLoc) {
14601    return checkModuleImportContext(*this, M, ImportLoc, CurContext);
14602  }
14603  
ActOnModuleImport(SourceLocation AtLoc,SourceLocation ImportLoc,ModuleIdPath Path)14604  DeclResult Sema::ActOnModuleImport(SourceLocation AtLoc,
14605                                     SourceLocation ImportLoc,
14606                                     ModuleIdPath Path) {
14607    Module *Mod =
14608        getModuleLoader().loadModule(ImportLoc, Path, Module::AllVisible,
14609                                     /*IsIncludeDirective=*/false);
14610    if (!Mod)
14611      return true;
14612  
14613    VisibleModules.setVisible(Mod, ImportLoc);
14614  
14615    checkModuleImportContext(*this, Mod, ImportLoc, CurContext);
14616  
14617    // FIXME: we should support importing a submodule within a different submodule
14618    // of the same top-level module. Until we do, make it an error rather than
14619    // silently ignoring the import.
14620    if (Mod->getTopLevelModuleName() == getLangOpts().CurrentModule)
14621      Diag(ImportLoc, diag::err_module_self_import)
14622          << Mod->getFullModuleName() << getLangOpts().CurrentModule;
14623    else if (Mod->getTopLevelModuleName() == getLangOpts().ImplementationOfModule)
14624      Diag(ImportLoc, diag::err_module_import_in_implementation)
14625          << Mod->getFullModuleName() << getLangOpts().ImplementationOfModule;
14626  
14627    SmallVector<SourceLocation, 2> IdentifierLocs;
14628    Module *ModCheck = Mod;
14629    for (unsigned I = 0, N = Path.size(); I != N; ++I) {
14630      // If we've run out of module parents, just drop the remaining identifiers.
14631      // We need the length to be consistent.
14632      if (!ModCheck)
14633        break;
14634      ModCheck = ModCheck->Parent;
14635  
14636      IdentifierLocs.push_back(Path[I].second);
14637    }
14638  
14639    ImportDecl *Import = ImportDecl::Create(Context,
14640                                            Context.getTranslationUnitDecl(),
14641                                            AtLoc.isValid()? AtLoc : ImportLoc,
14642                                            Mod, IdentifierLocs);
14643    Context.getTranslationUnitDecl()->addDecl(Import);
14644    return Import;
14645  }
14646  
ActOnModuleInclude(SourceLocation DirectiveLoc,Module * Mod)14647  void Sema::ActOnModuleInclude(SourceLocation DirectiveLoc, Module *Mod) {
14648    checkModuleImportContext(*this, Mod, DirectiveLoc, CurContext, true);
14649  
14650    // Determine whether we're in the #include buffer for a module. The #includes
14651    // in that buffer do not qualify as module imports; they're just an
14652    // implementation detail of us building the module.
14653    //
14654    // FIXME: Should we even get ActOnModuleInclude calls for those?
14655    bool IsInModuleIncludes =
14656        TUKind == TU_Module &&
14657        getSourceManager().isWrittenInMainFile(DirectiveLoc);
14658  
14659    // If this module import was due to an inclusion directive, create an
14660    // implicit import declaration to capture it in the AST.
14661    if (!IsInModuleIncludes) {
14662      TranslationUnitDecl *TU = getASTContext().getTranslationUnitDecl();
14663      ImportDecl *ImportD = ImportDecl::CreateImplicit(getASTContext(), TU,
14664                                                       DirectiveLoc, Mod,
14665                                                       DirectiveLoc);
14666      TU->addDecl(ImportD);
14667      Consumer.HandleImplicitImportDecl(ImportD);
14668    }
14669  
14670    getModuleLoader().makeModuleVisible(Mod, Module::AllVisible, DirectiveLoc);
14671    VisibleModules.setVisible(Mod, DirectiveLoc);
14672  }
14673  
ActOnModuleBegin(SourceLocation DirectiveLoc,Module * Mod)14674  void Sema::ActOnModuleBegin(SourceLocation DirectiveLoc, Module *Mod) {
14675    checkModuleImportContext(*this, Mod, DirectiveLoc, CurContext);
14676  
14677    if (getLangOpts().ModulesLocalVisibility)
14678      VisibleModulesStack.push_back(std::move(VisibleModules));
14679    VisibleModules.setVisible(Mod, DirectiveLoc);
14680  }
14681  
ActOnModuleEnd(SourceLocation DirectiveLoc,Module * Mod)14682  void Sema::ActOnModuleEnd(SourceLocation DirectiveLoc, Module *Mod) {
14683    checkModuleImportContext(*this, Mod, DirectiveLoc, CurContext);
14684  
14685    if (getLangOpts().ModulesLocalVisibility) {
14686      VisibleModules = std::move(VisibleModulesStack.back());
14687      VisibleModulesStack.pop_back();
14688      VisibleModules.setVisible(Mod, DirectiveLoc);
14689    }
14690  }
14691  
createImplicitModuleImportForErrorRecovery(SourceLocation Loc,Module * Mod)14692  void Sema::createImplicitModuleImportForErrorRecovery(SourceLocation Loc,
14693                                                        Module *Mod) {
14694    // Bail if we're not allowed to implicitly import a module here.
14695    if (isSFINAEContext() || !getLangOpts().ModulesErrorRecovery)
14696      return;
14697  
14698    // Create the implicit import declaration.
14699    TranslationUnitDecl *TU = getASTContext().getTranslationUnitDecl();
14700    ImportDecl *ImportD = ImportDecl::CreateImplicit(getASTContext(), TU,
14701                                                     Loc, Mod, Loc);
14702    TU->addDecl(ImportD);
14703    Consumer.HandleImplicitImportDecl(ImportD);
14704  
14705    // Make the module visible.
14706    getModuleLoader().makeModuleVisible(Mod, Module::AllVisible, Loc);
14707    VisibleModules.setVisible(Mod, Loc);
14708  }
14709  
ActOnPragmaRedefineExtname(IdentifierInfo * Name,IdentifierInfo * AliasName,SourceLocation PragmaLoc,SourceLocation NameLoc,SourceLocation AliasNameLoc)14710  void Sema::ActOnPragmaRedefineExtname(IdentifierInfo* Name,
14711                                        IdentifierInfo* AliasName,
14712                                        SourceLocation PragmaLoc,
14713                                        SourceLocation NameLoc,
14714                                        SourceLocation AliasNameLoc) {
14715    NamedDecl *PrevDecl = LookupSingleName(TUScope, Name, NameLoc,
14716                                           LookupOrdinaryName);
14717    AsmLabelAttr *Attr =
14718        AsmLabelAttr::CreateImplicit(Context, AliasName->getName(), AliasNameLoc);
14719  
14720    // If a declaration that:
14721    // 1) declares a function or a variable
14722    // 2) has external linkage
14723    // already exists, add a label attribute to it.
14724    if (PrevDecl && (isa<FunctionDecl>(PrevDecl) || isa<VarDecl>(PrevDecl))) {
14725      if (isDeclExternC(PrevDecl))
14726        PrevDecl->addAttr(Attr);
14727      else
14728        Diag(PrevDecl->getLocation(), diag::warn_redefine_extname_not_applied)
14729            << /*Variable*/(isa<FunctionDecl>(PrevDecl) ? 0 : 1) << PrevDecl;
14730    // Otherwise, add a label atttibute to ExtnameUndeclaredIdentifiers.
14731    } else
14732      (void)ExtnameUndeclaredIdentifiers.insert(std::make_pair(Name, Attr));
14733  }
14734  
ActOnPragmaWeakID(IdentifierInfo * Name,SourceLocation PragmaLoc,SourceLocation NameLoc)14735  void Sema::ActOnPragmaWeakID(IdentifierInfo* Name,
14736                               SourceLocation PragmaLoc,
14737                               SourceLocation NameLoc) {
14738    Decl *PrevDecl = LookupSingleName(TUScope, Name, NameLoc, LookupOrdinaryName);
14739  
14740    if (PrevDecl) {
14741      PrevDecl->addAttr(WeakAttr::CreateImplicit(Context, PragmaLoc));
14742    } else {
14743      (void)WeakUndeclaredIdentifiers.insert(
14744        std::pair<IdentifierInfo*,WeakInfo>
14745          (Name, WeakInfo((IdentifierInfo*)nullptr, NameLoc)));
14746    }
14747  }
14748  
ActOnPragmaWeakAlias(IdentifierInfo * Name,IdentifierInfo * AliasName,SourceLocation PragmaLoc,SourceLocation NameLoc,SourceLocation AliasNameLoc)14749  void Sema::ActOnPragmaWeakAlias(IdentifierInfo* Name,
14750                                  IdentifierInfo* AliasName,
14751                                  SourceLocation PragmaLoc,
14752                                  SourceLocation NameLoc,
14753                                  SourceLocation AliasNameLoc) {
14754    Decl *PrevDecl = LookupSingleName(TUScope, AliasName, AliasNameLoc,
14755                                      LookupOrdinaryName);
14756    WeakInfo W = WeakInfo(Name, NameLoc);
14757  
14758    if (PrevDecl && (isa<FunctionDecl>(PrevDecl) || isa<VarDecl>(PrevDecl))) {
14759      if (!PrevDecl->hasAttr<AliasAttr>())
14760        if (NamedDecl *ND = dyn_cast<NamedDecl>(PrevDecl))
14761          DeclApplyPragmaWeak(TUScope, ND, W);
14762    } else {
14763      (void)WeakUndeclaredIdentifiers.insert(
14764        std::pair<IdentifierInfo*,WeakInfo>(AliasName, W));
14765    }
14766  }
14767  
getObjCDeclContext() const14768  Decl *Sema::getObjCDeclContext() const {
14769    return (dyn_cast_or_null<ObjCContainerDecl>(CurContext));
14770  }
14771  
getCurContextAvailability() const14772  AvailabilityResult Sema::getCurContextAvailability() const {
14773    const Decl *D = cast_or_null<Decl>(getCurObjCLexicalContext());
14774    if (!D)
14775      return AR_Available;
14776  
14777    // If we are within an Objective-C method, we should consult
14778    // both the availability of the method as well as the
14779    // enclosing class.  If the class is (say) deprecated,
14780    // the entire method is considered deprecated from the
14781    // purpose of checking if the current context is deprecated.
14782    if (const ObjCMethodDecl *MD = dyn_cast<ObjCMethodDecl>(D)) {
14783      AvailabilityResult R = MD->getAvailability();
14784      if (R != AR_Available)
14785        return R;
14786      D = MD->getClassInterface();
14787    }
14788    // If we are within an Objective-c @implementation, it
14789    // gets the same availability context as the @interface.
14790    else if (const ObjCImplementationDecl *ID =
14791              dyn_cast<ObjCImplementationDecl>(D)) {
14792      D = ID->getClassInterface();
14793    }
14794    // Recover from user error.
14795    return D ? D->getAvailability() : AR_Available;
14796  }
14797