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1 //===--- Sema.cpp - AST Builder and Semantic Analysis Implementation ------===//
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 the actions class which performs semantic analysis and
11 // builds an AST out of a parse stream.
12 //
13 //===----------------------------------------------------------------------===//
14 
15 #include "clang/Sema/SemaInternal.h"
16 #include "clang/AST/ASTContext.h"
17 #include "clang/AST/ASTDiagnostic.h"
18 #include "clang/AST/DeclCXX.h"
19 #include "clang/AST/DeclFriend.h"
20 #include "clang/AST/DeclObjC.h"
21 #include "clang/AST/Expr.h"
22 #include "clang/AST/ExprCXX.h"
23 #include "clang/AST/StmtCXX.h"
24 #include "clang/Basic/DiagnosticOptions.h"
25 #include "clang/Basic/FileManager.h"
26 #include "clang/Basic/PartialDiagnostic.h"
27 #include "clang/Basic/TargetInfo.h"
28 #include "clang/Lex/HeaderSearch.h"
29 #include "clang/Lex/Preprocessor.h"
30 #include "clang/Sema/CXXFieldCollector.h"
31 #include "clang/Sema/DelayedDiagnostic.h"
32 #include "clang/Sema/ExternalSemaSource.h"
33 #include "clang/Sema/MultiplexExternalSemaSource.h"
34 #include "clang/Sema/ObjCMethodList.h"
35 #include "clang/Sema/PrettyDeclStackTrace.h"
36 #include "clang/Sema/Scope.h"
37 #include "clang/Sema/ScopeInfo.h"
38 #include "clang/Sema/SemaConsumer.h"
39 #include "clang/Sema/TemplateDeduction.h"
40 #include "llvm/ADT/APFloat.h"
41 #include "llvm/ADT/DenseMap.h"
42 #include "llvm/ADT/SmallSet.h"
43 using namespace clang;
44 using namespace sema;
45 
getLocForEndOfToken(SourceLocation Loc,unsigned Offset)46 SourceLocation Sema::getLocForEndOfToken(SourceLocation Loc, unsigned Offset) {
47   return Lexer::getLocForEndOfToken(Loc, Offset, SourceMgr, LangOpts);
48 }
49 
getModuleLoader() const50 ModuleLoader &Sema::getModuleLoader() const { return PP.getModuleLoader(); }
51 
getPrintingPolicy(const ASTContext & Context,const Preprocessor & PP)52 PrintingPolicy Sema::getPrintingPolicy(const ASTContext &Context,
53                                        const Preprocessor &PP) {
54   PrintingPolicy Policy = Context.getPrintingPolicy();
55   // Our printing policy is copied over the ASTContext printing policy whenever
56   // a diagnostic is emitted, so recompute it.
57   Policy.Bool = Context.getLangOpts().Bool;
58   if (!Policy.Bool) {
59     if (const MacroInfo *BoolMacro = PP.getMacroInfo(Context.getBoolName())) {
60       Policy.Bool = BoolMacro->isObjectLike() &&
61                     BoolMacro->getNumTokens() == 1 &&
62                     BoolMacro->getReplacementToken(0).is(tok::kw__Bool);
63     }
64   }
65 
66   return Policy;
67 }
68 
ActOnTranslationUnitScope(Scope * S)69 void Sema::ActOnTranslationUnitScope(Scope *S) {
70   TUScope = S;
71   PushDeclContext(S, Context.getTranslationUnitDecl());
72 }
73 
Sema(Preprocessor & pp,ASTContext & ctxt,ASTConsumer & consumer,TranslationUnitKind TUKind,CodeCompleteConsumer * CodeCompleter)74 Sema::Sema(Preprocessor &pp, ASTContext &ctxt, ASTConsumer &consumer,
75            TranslationUnitKind TUKind,
76            CodeCompleteConsumer *CodeCompleter)
77   : ExternalSource(nullptr),
78     isMultiplexExternalSource(false), FPFeatures(pp.getLangOpts()),
79     LangOpts(pp.getLangOpts()), PP(pp), Context(ctxt), Consumer(consumer),
80     Diags(PP.getDiagnostics()), SourceMgr(PP.getSourceManager()),
81     CollectStats(false), CodeCompleter(CodeCompleter),
82     CurContext(nullptr), OriginalLexicalContext(nullptr),
83     MSStructPragmaOn(false),
84     MSPointerToMemberRepresentationMethod(
85         LangOpts.getMSPointerToMemberRepresentationMethod()),
86     VtorDispStack(MSVtorDispAttr::Mode(LangOpts.VtorDispMode)),
87     PackStack(0), DataSegStack(nullptr), BSSSegStack(nullptr),
88     ConstSegStack(nullptr), CodeSegStack(nullptr), CurInitSeg(nullptr),
89     VisContext(nullptr),
90     IsBuildingRecoveryCallExpr(false),
91     Cleanup{}, LateTemplateParser(nullptr),
92     LateTemplateParserCleanup(nullptr),
93     OpaqueParser(nullptr), IdResolver(pp), StdInitializerList(nullptr),
94     CXXTypeInfoDecl(nullptr), MSVCGuidDecl(nullptr),
95     NSNumberDecl(nullptr), NSValueDecl(nullptr),
96     NSStringDecl(nullptr), StringWithUTF8StringMethod(nullptr),
97     ValueWithBytesObjCTypeMethod(nullptr),
98     NSArrayDecl(nullptr), ArrayWithObjectsMethod(nullptr),
99     NSDictionaryDecl(nullptr), DictionaryWithObjectsMethod(nullptr),
100     MSAsmLabelNameCounter(0),
101     GlobalNewDeleteDeclared(false),
102     TUKind(TUKind),
103     NumSFINAEErrors(0),
104     CachedFakeTopLevelModule(nullptr),
105     AccessCheckingSFINAE(false), InNonInstantiationSFINAEContext(false),
106     NonInstantiationEntries(0), ArgumentPackSubstitutionIndex(-1),
107     CurrentInstantiationScope(nullptr), DisableTypoCorrection(false),
108     TyposCorrected(0), AnalysisWarnings(*this), ThreadSafetyDeclCache(nullptr),
109     VarDataSharingAttributesStack(nullptr), CurScope(nullptr),
110     Ident_super(nullptr), Ident___float128(nullptr)
111 {
112   TUScope = nullptr;
113 
114   LoadedExternalKnownNamespaces = false;
115   for (unsigned I = 0; I != NSAPI::NumNSNumberLiteralMethods; ++I)
116     NSNumberLiteralMethods[I] = nullptr;
117 
118   if (getLangOpts().ObjC1)
119     NSAPIObj.reset(new NSAPI(Context));
120 
121   if (getLangOpts().CPlusPlus)
122     FieldCollector.reset(new CXXFieldCollector());
123 
124   // Tell diagnostics how to render things from the AST library.
125   Diags.SetArgToStringFn(&FormatASTNodeDiagnosticArgument, &Context);
126 
127   ExprEvalContexts.emplace_back(PotentiallyEvaluated, 0, CleanupInfo{}, nullptr,
128                                 false);
129 
130   FunctionScopes.push_back(new FunctionScopeInfo(Diags));
131 
132   // Initilization of data sharing attributes stack for OpenMP
133   InitDataSharingAttributesStack();
134 }
135 
addImplicitTypedef(StringRef Name,QualType T)136 void Sema::addImplicitTypedef(StringRef Name, QualType T) {
137   DeclarationName DN = &Context.Idents.get(Name);
138   if (IdResolver.begin(DN) == IdResolver.end())
139     PushOnScopeChains(Context.buildImplicitTypedef(T, Name), TUScope);
140 }
141 
Initialize()142 void Sema::Initialize() {
143   if (SemaConsumer *SC = dyn_cast<SemaConsumer>(&Consumer))
144     SC->InitializeSema(*this);
145 
146   // Tell the external Sema source about this Sema object.
147   if (ExternalSemaSource *ExternalSema
148       = dyn_cast_or_null<ExternalSemaSource>(Context.getExternalSource()))
149     ExternalSema->InitializeSema(*this);
150 
151   // This needs to happen after ExternalSemaSource::InitializeSema(this) or we
152   // will not be able to merge any duplicate __va_list_tag decls correctly.
153   VAListTagName = PP.getIdentifierInfo("__va_list_tag");
154 
155   if (!TUScope)
156     return;
157 
158   // Initialize predefined 128-bit integer types, if needed.
159   if (Context.getTargetInfo().hasInt128Type()) {
160     // If either of the 128-bit integer types are unavailable to name lookup,
161     // define them now.
162     DeclarationName Int128 = &Context.Idents.get("__int128_t");
163     if (IdResolver.begin(Int128) == IdResolver.end())
164       PushOnScopeChains(Context.getInt128Decl(), TUScope);
165 
166     DeclarationName UInt128 = &Context.Idents.get("__uint128_t");
167     if (IdResolver.begin(UInt128) == IdResolver.end())
168       PushOnScopeChains(Context.getUInt128Decl(), TUScope);
169   }
170 
171 
172   // Initialize predefined Objective-C types:
173   if (getLangOpts().ObjC1) {
174     // If 'SEL' does not yet refer to any declarations, make it refer to the
175     // predefined 'SEL'.
176     DeclarationName SEL = &Context.Idents.get("SEL");
177     if (IdResolver.begin(SEL) == IdResolver.end())
178       PushOnScopeChains(Context.getObjCSelDecl(), TUScope);
179 
180     // If 'id' does not yet refer to any declarations, make it refer to the
181     // predefined 'id'.
182     DeclarationName Id = &Context.Idents.get("id");
183     if (IdResolver.begin(Id) == IdResolver.end())
184       PushOnScopeChains(Context.getObjCIdDecl(), TUScope);
185 
186     // Create the built-in typedef for 'Class'.
187     DeclarationName Class = &Context.Idents.get("Class");
188     if (IdResolver.begin(Class) == IdResolver.end())
189       PushOnScopeChains(Context.getObjCClassDecl(), TUScope);
190 
191     // Create the built-in forward declaratino for 'Protocol'.
192     DeclarationName Protocol = &Context.Idents.get("Protocol");
193     if (IdResolver.begin(Protocol) == IdResolver.end())
194       PushOnScopeChains(Context.getObjCProtocolDecl(), TUScope);
195   }
196 
197   // Create the internal type for the *StringMakeConstantString builtins.
198   DeclarationName ConstantString = &Context.Idents.get("__NSConstantString");
199   if (IdResolver.begin(ConstantString) == IdResolver.end())
200     PushOnScopeChains(Context.getCFConstantStringDecl(), TUScope);
201 
202   // Initialize Microsoft "predefined C++ types".
203   if (getLangOpts().MSVCCompat) {
204     if (getLangOpts().CPlusPlus &&
205         IdResolver.begin(&Context.Idents.get("type_info")) == IdResolver.end())
206       PushOnScopeChains(Context.buildImplicitRecord("type_info", TTK_Class),
207                         TUScope);
208 
209     addImplicitTypedef("size_t", Context.getSizeType());
210   }
211 
212   // Initialize predefined OpenCL types and supported optional core features.
213   if (getLangOpts().OpenCL) {
214 #define OPENCLEXT(Ext) \
215      if (Context.getTargetInfo().getSupportedOpenCLOpts().is_##Ext##_supported_core( \
216          getLangOpts().OpenCLVersion)) \
217        getOpenCLOptions().Ext = 1;
218 #include "clang/Basic/OpenCLExtensions.def"
219 
220     addImplicitTypedef("sampler_t", Context.OCLSamplerTy);
221     addImplicitTypedef("event_t", Context.OCLEventTy);
222     if (getLangOpts().OpenCLVersion >= 200) {
223       addImplicitTypedef("clk_event_t", Context.OCLClkEventTy);
224       addImplicitTypedef("queue_t", Context.OCLQueueTy);
225       addImplicitTypedef("ndrange_t", Context.OCLNDRangeTy);
226       addImplicitTypedef("reserve_id_t", Context.OCLReserveIDTy);
227       addImplicitTypedef("atomic_int", Context.getAtomicType(Context.IntTy));
228       addImplicitTypedef("atomic_uint",
229                          Context.getAtomicType(Context.UnsignedIntTy));
230       addImplicitTypedef("atomic_long", Context.getAtomicType(Context.LongTy));
231       addImplicitTypedef("atomic_ulong",
232                          Context.getAtomicType(Context.UnsignedLongTy));
233       addImplicitTypedef("atomic_float",
234                          Context.getAtomicType(Context.FloatTy));
235       addImplicitTypedef("atomic_double",
236                          Context.getAtomicType(Context.DoubleTy));
237       // OpenCLC v2.0, s6.13.11.6 requires that atomic_flag is implemented as
238       // 32-bit integer and OpenCLC v2.0, s6.1.1 int is always 32-bit wide.
239       addImplicitTypedef("atomic_flag", Context.getAtomicType(Context.IntTy));
240       addImplicitTypedef("atomic_intptr_t",
241                          Context.getAtomicType(Context.getIntPtrType()));
242       addImplicitTypedef("atomic_uintptr_t",
243                          Context.getAtomicType(Context.getUIntPtrType()));
244       addImplicitTypedef("atomic_size_t",
245                          Context.getAtomicType(Context.getSizeType()));
246       addImplicitTypedef("atomic_ptrdiff_t",
247                          Context.getAtomicType(Context.getPointerDiffType()));
248     }
249   }
250 
251   if (Context.getTargetInfo().hasBuiltinMSVaList()) {
252     DeclarationName MSVaList = &Context.Idents.get("__builtin_ms_va_list");
253     if (IdResolver.begin(MSVaList) == IdResolver.end())
254       PushOnScopeChains(Context.getBuiltinMSVaListDecl(), TUScope);
255   }
256 
257   DeclarationName BuiltinVaList = &Context.Idents.get("__builtin_va_list");
258   if (IdResolver.begin(BuiltinVaList) == IdResolver.end())
259     PushOnScopeChains(Context.getBuiltinVaListDecl(), TUScope);
260 }
261 
~Sema()262 Sema::~Sema() {
263   llvm::DeleteContainerSeconds(LateParsedTemplateMap);
264   if (VisContext) FreeVisContext();
265   // Kill all the active scopes.
266   for (unsigned I = 1, E = FunctionScopes.size(); I != E; ++I)
267     delete FunctionScopes[I];
268   if (FunctionScopes.size() == 1)
269     delete FunctionScopes[0];
270 
271   // Tell the SemaConsumer to forget about us; we're going out of scope.
272   if (SemaConsumer *SC = dyn_cast<SemaConsumer>(&Consumer))
273     SC->ForgetSema();
274 
275   // Detach from the external Sema source.
276   if (ExternalSemaSource *ExternalSema
277         = dyn_cast_or_null<ExternalSemaSource>(Context.getExternalSource()))
278     ExternalSema->ForgetSema();
279 
280   // If Sema's ExternalSource is the multiplexer - we own it.
281   if (isMultiplexExternalSource)
282     delete ExternalSource;
283 
284   threadSafety::threadSafetyCleanup(ThreadSafetyDeclCache);
285 
286   // Destroys data sharing attributes stack for OpenMP
287   DestroyDataSharingAttributesStack();
288 
289   assert(DelayedTypos.empty() && "Uncorrected typos!");
290 }
291 
292 /// makeUnavailableInSystemHeader - There is an error in the current
293 /// context.  If we're still in a system header, and we can plausibly
294 /// make the relevant declaration unavailable instead of erroring, do
295 /// so and return true.
makeUnavailableInSystemHeader(SourceLocation loc,UnavailableAttr::ImplicitReason reason)296 bool Sema::makeUnavailableInSystemHeader(SourceLocation loc,
297                                       UnavailableAttr::ImplicitReason reason) {
298   // If we're not in a function, it's an error.
299   FunctionDecl *fn = dyn_cast<FunctionDecl>(CurContext);
300   if (!fn) return false;
301 
302   // If we're in template instantiation, it's an error.
303   if (!ActiveTemplateInstantiations.empty())
304     return false;
305 
306   // If that function's not in a system header, it's an error.
307   if (!Context.getSourceManager().isInSystemHeader(loc))
308     return false;
309 
310   // If the function is already unavailable, it's not an error.
311   if (fn->hasAttr<UnavailableAttr>()) return true;
312 
313   fn->addAttr(UnavailableAttr::CreateImplicit(Context, "", reason, loc));
314   return true;
315 }
316 
getASTMutationListener() const317 ASTMutationListener *Sema::getASTMutationListener() const {
318   return getASTConsumer().GetASTMutationListener();
319 }
320 
321 ///\brief Registers an external source. If an external source already exists,
322 /// creates a multiplex external source and appends to it.
323 ///
324 ///\param[in] E - A non-null external sema source.
325 ///
addExternalSource(ExternalSemaSource * E)326 void Sema::addExternalSource(ExternalSemaSource *E) {
327   assert(E && "Cannot use with NULL ptr");
328 
329   if (!ExternalSource) {
330     ExternalSource = E;
331     return;
332   }
333 
334   if (isMultiplexExternalSource)
335     static_cast<MultiplexExternalSemaSource*>(ExternalSource)->addSource(*E);
336   else {
337     ExternalSource = new MultiplexExternalSemaSource(*ExternalSource, *E);
338     isMultiplexExternalSource = true;
339   }
340 }
341 
342 /// \brief Print out statistics about the semantic analysis.
PrintStats() const343 void Sema::PrintStats() const {
344   llvm::errs() << "\n*** Semantic Analysis Stats:\n";
345   llvm::errs() << NumSFINAEErrors << " SFINAE diagnostics trapped.\n";
346 
347   BumpAlloc.PrintStats();
348   AnalysisWarnings.PrintStats();
349 }
350 
diagnoseNullableToNonnullConversion(QualType DstType,QualType SrcType,SourceLocation Loc)351 void Sema::diagnoseNullableToNonnullConversion(QualType DstType,
352                                                QualType SrcType,
353                                                SourceLocation Loc) {
354   Optional<NullabilityKind> ExprNullability = SrcType->getNullability(Context);
355   if (!ExprNullability || *ExprNullability != NullabilityKind::Nullable)
356     return;
357 
358   Optional<NullabilityKind> TypeNullability = DstType->getNullability(Context);
359   if (!TypeNullability || *TypeNullability != NullabilityKind::NonNull)
360     return;
361 
362   Diag(Loc, diag::warn_nullability_lost) << SrcType << DstType;
363 }
364 
365 /// ImpCastExprToType - If Expr is not of type 'Type', insert an implicit cast.
366 /// If there is already an implicit cast, merge into the existing one.
367 /// The result is of the given category.
ImpCastExprToType(Expr * E,QualType Ty,CastKind Kind,ExprValueKind VK,const CXXCastPath * BasePath,CheckedConversionKind CCK)368 ExprResult Sema::ImpCastExprToType(Expr *E, QualType Ty,
369                                    CastKind Kind, ExprValueKind VK,
370                                    const CXXCastPath *BasePath,
371                                    CheckedConversionKind CCK) {
372 #ifndef NDEBUG
373   if (VK == VK_RValue && !E->isRValue()) {
374     switch (Kind) {
375     default:
376       llvm_unreachable("can't implicitly cast lvalue to rvalue with this cast "
377                        "kind");
378     case CK_LValueToRValue:
379     case CK_ArrayToPointerDecay:
380     case CK_FunctionToPointerDecay:
381     case CK_ToVoid:
382       break;
383     }
384   }
385   assert((VK == VK_RValue || !E->isRValue()) && "can't cast rvalue to lvalue");
386 #endif
387 
388   diagnoseNullableToNonnullConversion(Ty, E->getType(), E->getLocStart());
389 
390   QualType ExprTy = Context.getCanonicalType(E->getType());
391   QualType TypeTy = Context.getCanonicalType(Ty);
392 
393   if (ExprTy == TypeTy)
394     return E;
395 
396   if (ImplicitCastExpr *ImpCast = dyn_cast<ImplicitCastExpr>(E)) {
397     if (ImpCast->getCastKind() == Kind && (!BasePath || BasePath->empty())) {
398       ImpCast->setType(Ty);
399       ImpCast->setValueKind(VK);
400       return E;
401     }
402   }
403 
404   return ImplicitCastExpr::Create(Context, Ty, Kind, E, BasePath, VK);
405 }
406 
407 /// ScalarTypeToBooleanCastKind - Returns the cast kind corresponding
408 /// to the conversion from scalar type ScalarTy to the Boolean type.
ScalarTypeToBooleanCastKind(QualType ScalarTy)409 CastKind Sema::ScalarTypeToBooleanCastKind(QualType ScalarTy) {
410   switch (ScalarTy->getScalarTypeKind()) {
411   case Type::STK_Bool: return CK_NoOp;
412   case Type::STK_CPointer: return CK_PointerToBoolean;
413   case Type::STK_BlockPointer: return CK_PointerToBoolean;
414   case Type::STK_ObjCObjectPointer: return CK_PointerToBoolean;
415   case Type::STK_MemberPointer: return CK_MemberPointerToBoolean;
416   case Type::STK_Integral: return CK_IntegralToBoolean;
417   case Type::STK_Floating: return CK_FloatingToBoolean;
418   case Type::STK_IntegralComplex: return CK_IntegralComplexToBoolean;
419   case Type::STK_FloatingComplex: return CK_FloatingComplexToBoolean;
420   }
421   return CK_Invalid;
422 }
423 
424 /// \brief Used to prune the decls of Sema's UnusedFileScopedDecls vector.
ShouldRemoveFromUnused(Sema * SemaRef,const DeclaratorDecl * D)425 static bool ShouldRemoveFromUnused(Sema *SemaRef, const DeclaratorDecl *D) {
426   if (D->getMostRecentDecl()->isUsed())
427     return true;
428 
429   if (D->isExternallyVisible())
430     return true;
431 
432   if (const FunctionDecl *FD = dyn_cast<FunctionDecl>(D)) {
433     // UnusedFileScopedDecls stores the first declaration.
434     // The declaration may have become definition so check again.
435     const FunctionDecl *DeclToCheck;
436     if (FD->hasBody(DeclToCheck))
437       return !SemaRef->ShouldWarnIfUnusedFileScopedDecl(DeclToCheck);
438 
439     // Later redecls may add new information resulting in not having to warn,
440     // so check again.
441     DeclToCheck = FD->getMostRecentDecl();
442     if (DeclToCheck != FD)
443       return !SemaRef->ShouldWarnIfUnusedFileScopedDecl(DeclToCheck);
444   }
445 
446   if (const VarDecl *VD = dyn_cast<VarDecl>(D)) {
447     // If a variable usable in constant expressions is referenced,
448     // don't warn if it isn't used: if the value of a variable is required
449     // for the computation of a constant expression, it doesn't make sense to
450     // warn even if the variable isn't odr-used.  (isReferenced doesn't
451     // precisely reflect that, but it's a decent approximation.)
452     if (VD->isReferenced() &&
453         VD->isUsableInConstantExpressions(SemaRef->Context))
454       return true;
455 
456     // UnusedFileScopedDecls stores the first declaration.
457     // The declaration may have become definition so check again.
458     const VarDecl *DeclToCheck = VD->getDefinition();
459     if (DeclToCheck)
460       return !SemaRef->ShouldWarnIfUnusedFileScopedDecl(DeclToCheck);
461 
462     // Later redecls may add new information resulting in not having to warn,
463     // so check again.
464     DeclToCheck = VD->getMostRecentDecl();
465     if (DeclToCheck != VD)
466       return !SemaRef->ShouldWarnIfUnusedFileScopedDecl(DeclToCheck);
467   }
468 
469   return false;
470 }
471 
472 /// Obtains a sorted list of functions and variables that are undefined but
473 /// ODR-used.
getUndefinedButUsed(SmallVectorImpl<std::pair<NamedDecl *,SourceLocation>> & Undefined)474 void Sema::getUndefinedButUsed(
475     SmallVectorImpl<std::pair<NamedDecl *, SourceLocation> > &Undefined) {
476   for (const auto &UndefinedUse : UndefinedButUsed) {
477     NamedDecl *ND = UndefinedUse.first;
478 
479     // Ignore attributes that have become invalid.
480     if (ND->isInvalidDecl()) continue;
481 
482     // __attribute__((weakref)) is basically a definition.
483     if (ND->hasAttr<WeakRefAttr>()) continue;
484 
485     if (FunctionDecl *FD = dyn_cast<FunctionDecl>(ND)) {
486       if (FD->isDefined())
487         continue;
488       if (FD->isExternallyVisible() &&
489           !FD->getMostRecentDecl()->isInlined())
490         continue;
491     } else {
492       auto *VD = cast<VarDecl>(ND);
493       if (VD->hasDefinition() != VarDecl::DeclarationOnly)
494         continue;
495       if (VD->isExternallyVisible() && !VD->getMostRecentDecl()->isInline())
496         continue;
497     }
498 
499     Undefined.push_back(std::make_pair(ND, UndefinedUse.second));
500   }
501 }
502 
503 /// checkUndefinedButUsed - Check for undefined objects with internal linkage
504 /// or that are inline.
checkUndefinedButUsed(Sema & S)505 static void checkUndefinedButUsed(Sema &S) {
506   if (S.UndefinedButUsed.empty()) return;
507 
508   // Collect all the still-undefined entities with internal linkage.
509   SmallVector<std::pair<NamedDecl *, SourceLocation>, 16> Undefined;
510   S.getUndefinedButUsed(Undefined);
511   if (Undefined.empty()) return;
512 
513   for (SmallVectorImpl<std::pair<NamedDecl *, SourceLocation> >::iterator
514          I = Undefined.begin(), E = Undefined.end(); I != E; ++I) {
515     NamedDecl *ND = I->first;
516 
517     if (ND->hasAttr<DLLImportAttr>() || ND->hasAttr<DLLExportAttr>()) {
518       // An exported function will always be emitted when defined, so even if
519       // the function is inline, it doesn't have to be emitted in this TU. An
520       // imported function implies that it has been exported somewhere else.
521       continue;
522     }
523 
524     if (!ND->isExternallyVisible()) {
525       S.Diag(ND->getLocation(), diag::warn_undefined_internal)
526         << isa<VarDecl>(ND) << ND;
527     } else if (auto *FD = dyn_cast<FunctionDecl>(ND)) {
528       (void)FD;
529       assert(FD->getMostRecentDecl()->isInlined() &&
530              "used object requires definition but isn't inline or internal?");
531       // FIXME: This is ill-formed; we should reject.
532       S.Diag(ND->getLocation(), diag::warn_undefined_inline) << ND;
533     } else {
534       assert(cast<VarDecl>(ND)->getMostRecentDecl()->isInline() &&
535              "used var requires definition but isn't inline or internal?");
536       S.Diag(ND->getLocation(), diag::err_undefined_inline_var) << ND;
537     }
538     if (I->second.isValid())
539       S.Diag(I->second, diag::note_used_here);
540   }
541 
542   S.UndefinedButUsed.clear();
543 }
544 
LoadExternalWeakUndeclaredIdentifiers()545 void Sema::LoadExternalWeakUndeclaredIdentifiers() {
546   if (!ExternalSource)
547     return;
548 
549   SmallVector<std::pair<IdentifierInfo *, WeakInfo>, 4> WeakIDs;
550   ExternalSource->ReadWeakUndeclaredIdentifiers(WeakIDs);
551   for (auto &WeakID : WeakIDs)
552     WeakUndeclaredIdentifiers.insert(WeakID);
553 }
554 
555 
556 typedef llvm::DenseMap<const CXXRecordDecl*, bool> RecordCompleteMap;
557 
558 /// \brief Returns true, if all methods and nested classes of the given
559 /// CXXRecordDecl are defined in this translation unit.
560 ///
561 /// Should only be called from ActOnEndOfTranslationUnit so that all
562 /// definitions are actually read.
MethodsAndNestedClassesComplete(const CXXRecordDecl * RD,RecordCompleteMap & MNCComplete)563 static bool MethodsAndNestedClassesComplete(const CXXRecordDecl *RD,
564                                             RecordCompleteMap &MNCComplete) {
565   RecordCompleteMap::iterator Cache = MNCComplete.find(RD);
566   if (Cache != MNCComplete.end())
567     return Cache->second;
568   if (!RD->isCompleteDefinition())
569     return false;
570   bool Complete = true;
571   for (DeclContext::decl_iterator I = RD->decls_begin(),
572                                   E = RD->decls_end();
573        I != E && Complete; ++I) {
574     if (const CXXMethodDecl *M = dyn_cast<CXXMethodDecl>(*I))
575       Complete = M->isDefined() || (M->isPure() && !isa<CXXDestructorDecl>(M));
576     else if (const FunctionTemplateDecl *F = dyn_cast<FunctionTemplateDecl>(*I))
577       // If the template function is marked as late template parsed at this
578       // point, it has not been instantiated and therefore we have not
579       // performed semantic analysis on it yet, so we cannot know if the type
580       // can be considered complete.
581       Complete = !F->getTemplatedDecl()->isLateTemplateParsed() &&
582                   F->getTemplatedDecl()->isDefined();
583     else if (const CXXRecordDecl *R = dyn_cast<CXXRecordDecl>(*I)) {
584       if (R->isInjectedClassName())
585         continue;
586       if (R->hasDefinition())
587         Complete = MethodsAndNestedClassesComplete(R->getDefinition(),
588                                                    MNCComplete);
589       else
590         Complete = false;
591     }
592   }
593   MNCComplete[RD] = Complete;
594   return Complete;
595 }
596 
597 /// \brief Returns true, if the given CXXRecordDecl is fully defined in this
598 /// translation unit, i.e. all methods are defined or pure virtual and all
599 /// friends, friend functions and nested classes are fully defined in this
600 /// translation unit.
601 ///
602 /// Should only be called from ActOnEndOfTranslationUnit so that all
603 /// definitions are actually read.
IsRecordFullyDefined(const CXXRecordDecl * RD,RecordCompleteMap & RecordsComplete,RecordCompleteMap & MNCComplete)604 static bool IsRecordFullyDefined(const CXXRecordDecl *RD,
605                                  RecordCompleteMap &RecordsComplete,
606                                  RecordCompleteMap &MNCComplete) {
607   RecordCompleteMap::iterator Cache = RecordsComplete.find(RD);
608   if (Cache != RecordsComplete.end())
609     return Cache->second;
610   bool Complete = MethodsAndNestedClassesComplete(RD, MNCComplete);
611   for (CXXRecordDecl::friend_iterator I = RD->friend_begin(),
612                                       E = RD->friend_end();
613        I != E && Complete; ++I) {
614     // Check if friend classes and methods are complete.
615     if (TypeSourceInfo *TSI = (*I)->getFriendType()) {
616       // Friend classes are available as the TypeSourceInfo of the FriendDecl.
617       if (CXXRecordDecl *FriendD = TSI->getType()->getAsCXXRecordDecl())
618         Complete = MethodsAndNestedClassesComplete(FriendD, MNCComplete);
619       else
620         Complete = false;
621     } else {
622       // Friend functions are available through the NamedDecl of FriendDecl.
623       if (const FunctionDecl *FD =
624           dyn_cast<FunctionDecl>((*I)->getFriendDecl()))
625         Complete = FD->isDefined();
626       else
627         // This is a template friend, give up.
628         Complete = false;
629     }
630   }
631   RecordsComplete[RD] = Complete;
632   return Complete;
633 }
634 
emitAndClearUnusedLocalTypedefWarnings()635 void Sema::emitAndClearUnusedLocalTypedefWarnings() {
636   if (ExternalSource)
637     ExternalSource->ReadUnusedLocalTypedefNameCandidates(
638         UnusedLocalTypedefNameCandidates);
639   for (const TypedefNameDecl *TD : UnusedLocalTypedefNameCandidates) {
640     if (TD->isReferenced())
641       continue;
642     Diag(TD->getLocation(), diag::warn_unused_local_typedef)
643         << isa<TypeAliasDecl>(TD) << TD->getDeclName();
644   }
645   UnusedLocalTypedefNameCandidates.clear();
646 }
647 
648 /// ActOnEndOfTranslationUnit - This is called at the very end of the
649 /// translation unit when EOF is reached and all but the top-level scope is
650 /// popped.
ActOnEndOfTranslationUnit()651 void Sema::ActOnEndOfTranslationUnit() {
652   assert(DelayedDiagnostics.getCurrentPool() == nullptr
653          && "reached end of translation unit with a pool attached?");
654 
655   // If code completion is enabled, don't perform any end-of-translation-unit
656   // work.
657   if (PP.isCodeCompletionEnabled())
658     return;
659 
660   // Complete translation units and modules define vtables and perform implicit
661   // instantiations. PCH files do not.
662   if (TUKind != TU_Prefix) {
663     DiagnoseUseOfUnimplementedSelectors();
664 
665     // If DefinedUsedVTables ends up marking any virtual member functions it
666     // might lead to more pending template instantiations, which we then need
667     // to instantiate.
668     DefineUsedVTables();
669 
670     // C++: Perform implicit template instantiations.
671     //
672     // FIXME: When we perform these implicit instantiations, we do not
673     // carefully keep track of the point of instantiation (C++ [temp.point]).
674     // This means that name lookup that occurs within the template
675     // instantiation will always happen at the end of the translation unit,
676     // so it will find some names that are not required to be found. This is
677     // valid, but we could do better by diagnosing if an instantiation uses a
678     // name that was not visible at its first point of instantiation.
679     if (ExternalSource) {
680       // Load pending instantiations from the external source.
681       SmallVector<PendingImplicitInstantiation, 4> Pending;
682       ExternalSource->ReadPendingInstantiations(Pending);
683       PendingInstantiations.insert(PendingInstantiations.begin(),
684                                    Pending.begin(), Pending.end());
685     }
686     PerformPendingInstantiations();
687 
688     if (LateTemplateParserCleanup)
689       LateTemplateParserCleanup(OpaqueParser);
690 
691     CheckDelayedMemberExceptionSpecs();
692   }
693 
694   // All delayed member exception specs should be checked or we end up accepting
695   // incompatible declarations.
696   // FIXME: This is wrong for TUKind == TU_Prefix. In that case, we need to
697   // write out the lists to the AST file (if any).
698   assert(DelayedDefaultedMemberExceptionSpecs.empty());
699   assert(DelayedExceptionSpecChecks.empty());
700 
701   // All dllexport classes should have been processed already.
702   assert(DelayedDllExportClasses.empty());
703 
704   // Remove file scoped decls that turned out to be used.
705   UnusedFileScopedDecls.erase(
706       std::remove_if(UnusedFileScopedDecls.begin(nullptr, true),
707                      UnusedFileScopedDecls.end(),
708                      std::bind1st(std::ptr_fun(ShouldRemoveFromUnused), this)),
709       UnusedFileScopedDecls.end());
710 
711   if (TUKind == TU_Prefix) {
712     // Translation unit prefixes don't need any of the checking below.
713     TUScope = nullptr;
714     return;
715   }
716 
717   // Check for #pragma weak identifiers that were never declared
718   LoadExternalWeakUndeclaredIdentifiers();
719   for (auto WeakID : WeakUndeclaredIdentifiers) {
720     if (WeakID.second.getUsed())
721       continue;
722 
723     Decl *PrevDecl = LookupSingleName(TUScope, WeakID.first, SourceLocation(),
724                                       LookupOrdinaryName);
725     if (PrevDecl != nullptr &&
726         !(isa<FunctionDecl>(PrevDecl) || isa<VarDecl>(PrevDecl)))
727       Diag(WeakID.second.getLocation(), diag::warn_attribute_wrong_decl_type)
728           << "'weak'" << ExpectedVariableOrFunction;
729     else
730       Diag(WeakID.second.getLocation(), diag::warn_weak_identifier_undeclared)
731           << WeakID.first;
732   }
733 
734   if (LangOpts.CPlusPlus11 &&
735       !Diags.isIgnored(diag::warn_delegating_ctor_cycle, SourceLocation()))
736     CheckDelegatingCtorCycles();
737 
738   if (!Diags.hasErrorOccurred()) {
739     if (ExternalSource)
740       ExternalSource->ReadUndefinedButUsed(UndefinedButUsed);
741     checkUndefinedButUsed(*this);
742   }
743 
744   if (TUKind == TU_Module) {
745     // If we are building a module, resolve all of the exported declarations
746     // now.
747     if (Module *CurrentModule = PP.getCurrentModule()) {
748       ModuleMap &ModMap = PP.getHeaderSearchInfo().getModuleMap();
749 
750       SmallVector<Module *, 2> Stack;
751       Stack.push_back(CurrentModule);
752       while (!Stack.empty()) {
753         Module *Mod = Stack.pop_back_val();
754 
755         // Resolve the exported declarations and conflicts.
756         // FIXME: Actually complain, once we figure out how to teach the
757         // diagnostic client to deal with complaints in the module map at this
758         // point.
759         ModMap.resolveExports(Mod, /*Complain=*/false);
760         ModMap.resolveUses(Mod, /*Complain=*/false);
761         ModMap.resolveConflicts(Mod, /*Complain=*/false);
762 
763         // Queue the submodules, so their exports will also be resolved.
764         Stack.append(Mod->submodule_begin(), Mod->submodule_end());
765       }
766     }
767 
768     // Warnings emitted in ActOnEndOfTranslationUnit() should be emitted for
769     // modules when they are built, not every time they are used.
770     emitAndClearUnusedLocalTypedefWarnings();
771 
772     // Modules don't need any of the checking below.
773     TUScope = nullptr;
774     return;
775   }
776 
777   // C99 6.9.2p2:
778   //   A declaration of an identifier for an object that has file
779   //   scope without an initializer, and without a storage-class
780   //   specifier or with the storage-class specifier static,
781   //   constitutes a tentative definition. If a translation unit
782   //   contains one or more tentative definitions for an identifier,
783   //   and the translation unit contains no external definition for
784   //   that identifier, then the behavior is exactly as if the
785   //   translation unit contains a file scope declaration of that
786   //   identifier, with the composite type as of the end of the
787   //   translation unit, with an initializer equal to 0.
788   llvm::SmallSet<VarDecl *, 32> Seen;
789   for (TentativeDefinitionsType::iterator
790             T = TentativeDefinitions.begin(ExternalSource),
791          TEnd = TentativeDefinitions.end();
792        T != TEnd; ++T)
793   {
794     VarDecl *VD = (*T)->getActingDefinition();
795 
796     // If the tentative definition was completed, getActingDefinition() returns
797     // null. If we've already seen this variable before, insert()'s second
798     // return value is false.
799     if (!VD || VD->isInvalidDecl() || !Seen.insert(VD).second)
800       continue;
801 
802     if (const IncompleteArrayType *ArrayT
803         = Context.getAsIncompleteArrayType(VD->getType())) {
804       // Set the length of the array to 1 (C99 6.9.2p5).
805       Diag(VD->getLocation(), diag::warn_tentative_incomplete_array);
806       llvm::APInt One(Context.getTypeSize(Context.getSizeType()), true);
807       QualType T = Context.getConstantArrayType(ArrayT->getElementType(),
808                                                 One, ArrayType::Normal, 0);
809       VD->setType(T);
810     } else if (RequireCompleteType(VD->getLocation(), VD->getType(),
811                                    diag::err_tentative_def_incomplete_type))
812       VD->setInvalidDecl();
813 
814     CheckCompleteVariableDeclaration(VD);
815 
816     // Notify the consumer that we've completed a tentative definition.
817     if (!VD->isInvalidDecl())
818       Consumer.CompleteTentativeDefinition(VD);
819 
820   }
821 
822   // If there were errors, disable 'unused' warnings since they will mostly be
823   // noise.
824   if (!Diags.hasErrorOccurred()) {
825     // Output warning for unused file scoped decls.
826     for (UnusedFileScopedDeclsType::iterator
827            I = UnusedFileScopedDecls.begin(ExternalSource),
828            E = UnusedFileScopedDecls.end(); I != E; ++I) {
829       if (ShouldRemoveFromUnused(this, *I))
830         continue;
831 
832       if (const FunctionDecl *FD = dyn_cast<FunctionDecl>(*I)) {
833         const FunctionDecl *DiagD;
834         if (!FD->hasBody(DiagD))
835           DiagD = FD;
836         if (DiagD->isDeleted())
837           continue; // Deleted functions are supposed to be unused.
838         if (DiagD->isReferenced()) {
839           if (isa<CXXMethodDecl>(DiagD))
840             Diag(DiagD->getLocation(), diag::warn_unneeded_member_function)
841                   << DiagD->getDeclName();
842           else {
843             if (FD->getStorageClass() == SC_Static &&
844                 !FD->isInlineSpecified() &&
845                 !SourceMgr.isInMainFile(
846                    SourceMgr.getExpansionLoc(FD->getLocation())))
847               Diag(DiagD->getLocation(),
848                    diag::warn_unneeded_static_internal_decl)
849                   << DiagD->getDeclName();
850             else
851               Diag(DiagD->getLocation(), diag::warn_unneeded_internal_decl)
852                    << /*function*/0 << DiagD->getDeclName();
853           }
854         } else {
855           Diag(DiagD->getLocation(),
856                isa<CXXMethodDecl>(DiagD) ? diag::warn_unused_member_function
857                                          : diag::warn_unused_function)
858                 << DiagD->getDeclName();
859         }
860       } else {
861         const VarDecl *DiagD = cast<VarDecl>(*I)->getDefinition();
862         if (!DiagD)
863           DiagD = cast<VarDecl>(*I);
864         if (DiagD->isReferenced()) {
865           Diag(DiagD->getLocation(), diag::warn_unneeded_internal_decl)
866                 << /*variable*/1 << DiagD->getDeclName();
867         } else if (DiagD->getType().isConstQualified()) {
868           Diag(DiagD->getLocation(), diag::warn_unused_const_variable)
869               << DiagD->getDeclName();
870         } else {
871           Diag(DiagD->getLocation(), diag::warn_unused_variable)
872               << DiagD->getDeclName();
873         }
874       }
875     }
876 
877     emitAndClearUnusedLocalTypedefWarnings();
878   }
879 
880   if (!Diags.isIgnored(diag::warn_unused_private_field, SourceLocation())) {
881     RecordCompleteMap RecordsComplete;
882     RecordCompleteMap MNCComplete;
883     for (NamedDeclSetType::iterator I = UnusedPrivateFields.begin(),
884          E = UnusedPrivateFields.end(); I != E; ++I) {
885       const NamedDecl *D = *I;
886       const CXXRecordDecl *RD = dyn_cast<CXXRecordDecl>(D->getDeclContext());
887       if (RD && !RD->isUnion() &&
888           IsRecordFullyDefined(RD, RecordsComplete, MNCComplete)) {
889         Diag(D->getLocation(), diag::warn_unused_private_field)
890               << D->getDeclName();
891       }
892     }
893   }
894 
895   if (!Diags.isIgnored(diag::warn_mismatched_delete_new, SourceLocation())) {
896     if (ExternalSource)
897       ExternalSource->ReadMismatchingDeleteExpressions(DeleteExprs);
898     for (const auto &DeletedFieldInfo : DeleteExprs) {
899       for (const auto &DeleteExprLoc : DeletedFieldInfo.second) {
900         AnalyzeDeleteExprMismatch(DeletedFieldInfo.first, DeleteExprLoc.first,
901                                   DeleteExprLoc.second);
902       }
903     }
904   }
905 
906   // Check we've noticed that we're no longer parsing the initializer for every
907   // variable. If we miss cases, then at best we have a performance issue and
908   // at worst a rejects-valid bug.
909   assert(ParsingInitForAutoVars.empty() &&
910          "Didn't unmark var as having its initializer parsed");
911 
912   TUScope = nullptr;
913 }
914 
915 
916 //===----------------------------------------------------------------------===//
917 // Helper functions.
918 //===----------------------------------------------------------------------===//
919 
getFunctionLevelDeclContext()920 DeclContext *Sema::getFunctionLevelDeclContext() {
921   DeclContext *DC = CurContext;
922 
923   while (true) {
924     if (isa<BlockDecl>(DC) || isa<EnumDecl>(DC) || isa<CapturedDecl>(DC)) {
925       DC = DC->getParent();
926     } else if (isa<CXXMethodDecl>(DC) &&
927                cast<CXXMethodDecl>(DC)->getOverloadedOperator() == OO_Call &&
928                cast<CXXRecordDecl>(DC->getParent())->isLambda()) {
929       DC = DC->getParent()->getParent();
930     }
931     else break;
932   }
933 
934   return DC;
935 }
936 
937 /// getCurFunctionDecl - If inside of a function body, this returns a pointer
938 /// to the function decl for the function being parsed.  If we're currently
939 /// in a 'block', this returns the containing context.
getCurFunctionDecl()940 FunctionDecl *Sema::getCurFunctionDecl() {
941   DeclContext *DC = getFunctionLevelDeclContext();
942   return dyn_cast<FunctionDecl>(DC);
943 }
944 
getCurMethodDecl()945 ObjCMethodDecl *Sema::getCurMethodDecl() {
946   DeclContext *DC = getFunctionLevelDeclContext();
947   while (isa<RecordDecl>(DC))
948     DC = DC->getParent();
949   return dyn_cast<ObjCMethodDecl>(DC);
950 }
951 
getCurFunctionOrMethodDecl()952 NamedDecl *Sema::getCurFunctionOrMethodDecl() {
953   DeclContext *DC = getFunctionLevelDeclContext();
954   if (isa<ObjCMethodDecl>(DC) || isa<FunctionDecl>(DC))
955     return cast<NamedDecl>(DC);
956   return nullptr;
957 }
958 
EmitCurrentDiagnostic(unsigned DiagID)959 void Sema::EmitCurrentDiagnostic(unsigned DiagID) {
960   // FIXME: It doesn't make sense to me that DiagID is an incoming argument here
961   // and yet we also use the current diag ID on the DiagnosticsEngine. This has
962   // been made more painfully obvious by the refactor that introduced this
963   // function, but it is possible that the incoming argument can be
964   // eliminnated. If it truly cannot be (for example, there is some reentrancy
965   // issue I am not seeing yet), then there should at least be a clarifying
966   // comment somewhere.
967   if (Optional<TemplateDeductionInfo*> Info = isSFINAEContext()) {
968     switch (DiagnosticIDs::getDiagnosticSFINAEResponse(
969               Diags.getCurrentDiagID())) {
970     case DiagnosticIDs::SFINAE_Report:
971       // We'll report the diagnostic below.
972       break;
973 
974     case DiagnosticIDs::SFINAE_SubstitutionFailure:
975       // Count this failure so that we know that template argument deduction
976       // has failed.
977       ++NumSFINAEErrors;
978 
979       // Make a copy of this suppressed diagnostic and store it with the
980       // template-deduction information.
981       if (*Info && !(*Info)->hasSFINAEDiagnostic()) {
982         Diagnostic DiagInfo(&Diags);
983         (*Info)->addSFINAEDiagnostic(DiagInfo.getLocation(),
984                        PartialDiagnostic(DiagInfo, Context.getDiagAllocator()));
985       }
986 
987       Diags.setLastDiagnosticIgnored();
988       Diags.Clear();
989       return;
990 
991     case DiagnosticIDs::SFINAE_AccessControl: {
992       // Per C++ Core Issue 1170, access control is part of SFINAE.
993       // Additionally, the AccessCheckingSFINAE flag can be used to temporarily
994       // make access control a part of SFINAE for the purposes of checking
995       // type traits.
996       if (!AccessCheckingSFINAE && !getLangOpts().CPlusPlus11)
997         break;
998 
999       SourceLocation Loc = Diags.getCurrentDiagLoc();
1000 
1001       // Suppress this diagnostic.
1002       ++NumSFINAEErrors;
1003 
1004       // Make a copy of this suppressed diagnostic and store it with the
1005       // template-deduction information.
1006       if (*Info && !(*Info)->hasSFINAEDiagnostic()) {
1007         Diagnostic DiagInfo(&Diags);
1008         (*Info)->addSFINAEDiagnostic(DiagInfo.getLocation(),
1009                        PartialDiagnostic(DiagInfo, Context.getDiagAllocator()));
1010       }
1011 
1012       Diags.setLastDiagnosticIgnored();
1013       Diags.Clear();
1014 
1015       // Now the diagnostic state is clear, produce a C++98 compatibility
1016       // warning.
1017       Diag(Loc, diag::warn_cxx98_compat_sfinae_access_control);
1018 
1019       // The last diagnostic which Sema produced was ignored. Suppress any
1020       // notes attached to it.
1021       Diags.setLastDiagnosticIgnored();
1022       return;
1023     }
1024 
1025     case DiagnosticIDs::SFINAE_Suppress:
1026       // Make a copy of this suppressed diagnostic and store it with the
1027       // template-deduction information;
1028       if (*Info) {
1029         Diagnostic DiagInfo(&Diags);
1030         (*Info)->addSuppressedDiagnostic(DiagInfo.getLocation(),
1031                        PartialDiagnostic(DiagInfo, Context.getDiagAllocator()));
1032       }
1033 
1034       // Suppress this diagnostic.
1035       Diags.setLastDiagnosticIgnored();
1036       Diags.Clear();
1037       return;
1038     }
1039   }
1040 
1041   // Set up the context's printing policy based on our current state.
1042   Context.setPrintingPolicy(getPrintingPolicy());
1043 
1044   // Emit the diagnostic.
1045   if (!Diags.EmitCurrentDiagnostic())
1046     return;
1047 
1048   // If this is not a note, and we're in a template instantiation
1049   // that is different from the last template instantiation where
1050   // we emitted an error, print a template instantiation
1051   // backtrace.
1052   if (!DiagnosticIDs::isBuiltinNote(DiagID) &&
1053       !ActiveTemplateInstantiations.empty() &&
1054       ActiveTemplateInstantiations.back()
1055         != LastTemplateInstantiationErrorContext) {
1056     PrintInstantiationStack();
1057     LastTemplateInstantiationErrorContext = ActiveTemplateInstantiations.back();
1058   }
1059 }
1060 
1061 Sema::SemaDiagnosticBuilder
Diag(SourceLocation Loc,const PartialDiagnostic & PD)1062 Sema::Diag(SourceLocation Loc, const PartialDiagnostic& PD) {
1063   SemaDiagnosticBuilder Builder(Diag(Loc, PD.getDiagID()));
1064   PD.Emit(Builder);
1065 
1066   return Builder;
1067 }
1068 
1069 /// \brief Looks through the macro-expansion chain for the given
1070 /// location, looking for a macro expansion with the given name.
1071 /// If one is found, returns true and sets the location to that
1072 /// expansion loc.
findMacroSpelling(SourceLocation & locref,StringRef name)1073 bool Sema::findMacroSpelling(SourceLocation &locref, StringRef name) {
1074   SourceLocation loc = locref;
1075   if (!loc.isMacroID()) return false;
1076 
1077   // There's no good way right now to look at the intermediate
1078   // expansions, so just jump to the expansion location.
1079   loc = getSourceManager().getExpansionLoc(loc);
1080 
1081   // If that's written with the name, stop here.
1082   SmallVector<char, 16> buffer;
1083   if (getPreprocessor().getSpelling(loc, buffer) == name) {
1084     locref = loc;
1085     return true;
1086   }
1087   return false;
1088 }
1089 
1090 /// \brief Determines the active Scope associated with the given declaration
1091 /// context.
1092 ///
1093 /// This routine maps a declaration context to the active Scope object that
1094 /// represents that declaration context in the parser. It is typically used
1095 /// from "scope-less" code (e.g., template instantiation, lazy creation of
1096 /// declarations) that injects a name for name-lookup purposes and, therefore,
1097 /// must update the Scope.
1098 ///
1099 /// \returns The scope corresponding to the given declaraion context, or NULL
1100 /// if no such scope is open.
getScopeForContext(DeclContext * Ctx)1101 Scope *Sema::getScopeForContext(DeclContext *Ctx) {
1102 
1103   if (!Ctx)
1104     return nullptr;
1105 
1106   Ctx = Ctx->getPrimaryContext();
1107   for (Scope *S = getCurScope(); S; S = S->getParent()) {
1108     // Ignore scopes that cannot have declarations. This is important for
1109     // out-of-line definitions of static class members.
1110     if (S->getFlags() & (Scope::DeclScope | Scope::TemplateParamScope))
1111       if (DeclContext *Entity = S->getEntity())
1112         if (Ctx == Entity->getPrimaryContext())
1113           return S;
1114   }
1115 
1116   return nullptr;
1117 }
1118 
1119 /// \brief Enter a new function scope
PushFunctionScope()1120 void Sema::PushFunctionScope() {
1121   if (FunctionScopes.size() == 1) {
1122     // Use the "top" function scope rather than having to allocate
1123     // memory for a new scope.
1124     FunctionScopes.back()->Clear();
1125     FunctionScopes.push_back(FunctionScopes.back());
1126     return;
1127   }
1128 
1129   FunctionScopes.push_back(new FunctionScopeInfo(getDiagnostics()));
1130 }
1131 
PushBlockScope(Scope * BlockScope,BlockDecl * Block)1132 void Sema::PushBlockScope(Scope *BlockScope, BlockDecl *Block) {
1133   FunctionScopes.push_back(new BlockScopeInfo(getDiagnostics(),
1134                                               BlockScope, Block));
1135 }
1136 
PushLambdaScope()1137 LambdaScopeInfo *Sema::PushLambdaScope() {
1138   LambdaScopeInfo *const LSI = new LambdaScopeInfo(getDiagnostics());
1139   FunctionScopes.push_back(LSI);
1140   return LSI;
1141 }
1142 
RecordParsingTemplateParameterDepth(unsigned Depth)1143 void Sema::RecordParsingTemplateParameterDepth(unsigned Depth) {
1144   if (LambdaScopeInfo *const LSI = getCurLambda()) {
1145     LSI->AutoTemplateParameterDepth = Depth;
1146     return;
1147   }
1148   llvm_unreachable(
1149       "Remove assertion if intentionally called in a non-lambda context.");
1150 }
1151 
PopFunctionScopeInfo(const AnalysisBasedWarnings::Policy * WP,const Decl * D,const BlockExpr * blkExpr)1152 void Sema::PopFunctionScopeInfo(const AnalysisBasedWarnings::Policy *WP,
1153                                 const Decl *D, const BlockExpr *blkExpr) {
1154   FunctionScopeInfo *Scope = FunctionScopes.pop_back_val();
1155   assert(!FunctionScopes.empty() && "mismatched push/pop!");
1156 
1157   // Issue any analysis-based warnings.
1158   if (WP && D)
1159     AnalysisWarnings.IssueWarnings(*WP, Scope, D, blkExpr);
1160   else
1161     for (const auto &PUD : Scope->PossiblyUnreachableDiags)
1162       Diag(PUD.Loc, PUD.PD);
1163 
1164   if (FunctionScopes.back() != Scope)
1165     delete Scope;
1166 }
1167 
PushCompoundScope()1168 void Sema::PushCompoundScope() {
1169   getCurFunction()->CompoundScopes.push_back(CompoundScopeInfo());
1170 }
1171 
PopCompoundScope()1172 void Sema::PopCompoundScope() {
1173   FunctionScopeInfo *CurFunction = getCurFunction();
1174   assert(!CurFunction->CompoundScopes.empty() && "mismatched push/pop");
1175 
1176   CurFunction->CompoundScopes.pop_back();
1177 }
1178 
1179 /// \brief Determine whether any errors occurred within this function/method/
1180 /// block.
hasAnyUnrecoverableErrorsInThisFunction() const1181 bool Sema::hasAnyUnrecoverableErrorsInThisFunction() const {
1182   return getCurFunction()->ErrorTrap.hasUnrecoverableErrorOccurred();
1183 }
1184 
getCurBlock()1185 BlockScopeInfo *Sema::getCurBlock() {
1186   if (FunctionScopes.empty())
1187     return nullptr;
1188 
1189   auto CurBSI = dyn_cast<BlockScopeInfo>(FunctionScopes.back());
1190   if (CurBSI && CurBSI->TheDecl &&
1191       !CurBSI->TheDecl->Encloses(CurContext)) {
1192     // We have switched contexts due to template instantiation.
1193     assert(!ActiveTemplateInstantiations.empty());
1194     return nullptr;
1195   }
1196 
1197   return CurBSI;
1198 }
1199 
getCurLambda()1200 LambdaScopeInfo *Sema::getCurLambda() {
1201   if (FunctionScopes.empty())
1202     return nullptr;
1203 
1204   auto CurLSI = dyn_cast<LambdaScopeInfo>(FunctionScopes.back());
1205   if (CurLSI && CurLSI->Lambda &&
1206       !CurLSI->Lambda->Encloses(CurContext)) {
1207     // We have switched contexts due to template instantiation.
1208     assert(!ActiveTemplateInstantiations.empty());
1209     return nullptr;
1210   }
1211 
1212   return CurLSI;
1213 }
1214 // We have a generic lambda if we parsed auto parameters, or we have
1215 // an associated template parameter list.
getCurGenericLambda()1216 LambdaScopeInfo *Sema::getCurGenericLambda() {
1217   if (LambdaScopeInfo *LSI =  getCurLambda()) {
1218     return (LSI->AutoTemplateParams.size() ||
1219                     LSI->GLTemplateParameterList) ? LSI : nullptr;
1220   }
1221   return nullptr;
1222 }
1223 
1224 
ActOnComment(SourceRange Comment)1225 void Sema::ActOnComment(SourceRange Comment) {
1226   if (!LangOpts.RetainCommentsFromSystemHeaders &&
1227       SourceMgr.isInSystemHeader(Comment.getBegin()))
1228     return;
1229   RawComment RC(SourceMgr, Comment, false,
1230                 LangOpts.CommentOpts.ParseAllComments);
1231   if (RC.isAlmostTrailingComment()) {
1232     SourceRange MagicMarkerRange(Comment.getBegin(),
1233                                  Comment.getBegin().getLocWithOffset(3));
1234     StringRef MagicMarkerText;
1235     switch (RC.getKind()) {
1236     case RawComment::RCK_OrdinaryBCPL:
1237       MagicMarkerText = "///<";
1238       break;
1239     case RawComment::RCK_OrdinaryC:
1240       MagicMarkerText = "/**<";
1241       break;
1242     default:
1243       llvm_unreachable("if this is an almost Doxygen comment, "
1244                        "it should be ordinary");
1245     }
1246     Diag(Comment.getBegin(), diag::warn_not_a_doxygen_trailing_member_comment) <<
1247       FixItHint::CreateReplacement(MagicMarkerRange, MagicMarkerText);
1248   }
1249   Context.addComment(RC);
1250 }
1251 
1252 // Pin this vtable to this file.
~ExternalSemaSource()1253 ExternalSemaSource::~ExternalSemaSource() {}
1254 
ReadMethodPool(Selector Sel)1255 void ExternalSemaSource::ReadMethodPool(Selector Sel) { }
updateOutOfDateSelector(Selector Sel)1256 void ExternalSemaSource::updateOutOfDateSelector(Selector Sel) { }
1257 
ReadKnownNamespaces(SmallVectorImpl<NamespaceDecl * > & Namespaces)1258 void ExternalSemaSource::ReadKnownNamespaces(
1259                            SmallVectorImpl<NamespaceDecl *> &Namespaces) {
1260 }
1261 
ReadUndefinedButUsed(llvm::MapVector<NamedDecl *,SourceLocation> & Undefined)1262 void ExternalSemaSource::ReadUndefinedButUsed(
1263     llvm::MapVector<NamedDecl *, SourceLocation> &Undefined) {}
1264 
ReadMismatchingDeleteExpressions(llvm::MapVector<FieldDecl *,llvm::SmallVector<std::pair<SourceLocation,bool>,4>> &)1265 void ExternalSemaSource::ReadMismatchingDeleteExpressions(llvm::MapVector<
1266     FieldDecl *, llvm::SmallVector<std::pair<SourceLocation, bool>, 4>> &) {}
1267 
print(raw_ostream & OS) const1268 void PrettyDeclStackTraceEntry::print(raw_ostream &OS) const {
1269   SourceLocation Loc = this->Loc;
1270   if (!Loc.isValid() && TheDecl) Loc = TheDecl->getLocation();
1271   if (Loc.isValid()) {
1272     Loc.print(OS, S.getSourceManager());
1273     OS << ": ";
1274   }
1275   OS << Message;
1276 
1277   if (auto *ND = dyn_cast_or_null<NamedDecl>(TheDecl)) {
1278     OS << " '";
1279     ND->getNameForDiagnostic(OS, ND->getASTContext().getPrintingPolicy(), true);
1280     OS << "'";
1281   }
1282 
1283   OS << '\n';
1284 }
1285 
1286 /// \brief Figure out if an expression could be turned into a call.
1287 ///
1288 /// Use this when trying to recover from an error where the programmer may have
1289 /// written just the name of a function instead of actually calling it.
1290 ///
1291 /// \param E - The expression to examine.
1292 /// \param ZeroArgCallReturnTy - If the expression can be turned into a call
1293 ///  with no arguments, this parameter is set to the type returned by such a
1294 ///  call; otherwise, it is set to an empty QualType.
1295 /// \param OverloadSet - If the expression is an overloaded function
1296 ///  name, this parameter is populated with the decls of the various overloads.
tryExprAsCall(Expr & E,QualType & ZeroArgCallReturnTy,UnresolvedSetImpl & OverloadSet)1297 bool Sema::tryExprAsCall(Expr &E, QualType &ZeroArgCallReturnTy,
1298                          UnresolvedSetImpl &OverloadSet) {
1299   ZeroArgCallReturnTy = QualType();
1300   OverloadSet.clear();
1301 
1302   const OverloadExpr *Overloads = nullptr;
1303   bool IsMemExpr = false;
1304   if (E.getType() == Context.OverloadTy) {
1305     OverloadExpr::FindResult FR = OverloadExpr::find(const_cast<Expr*>(&E));
1306 
1307     // Ignore overloads that are pointer-to-member constants.
1308     if (FR.HasFormOfMemberPointer)
1309       return false;
1310 
1311     Overloads = FR.Expression;
1312   } else if (E.getType() == Context.BoundMemberTy) {
1313     Overloads = dyn_cast<UnresolvedMemberExpr>(E.IgnoreParens());
1314     IsMemExpr = true;
1315   }
1316 
1317   bool Ambiguous = false;
1318 
1319   if (Overloads) {
1320     for (OverloadExpr::decls_iterator it = Overloads->decls_begin(),
1321          DeclsEnd = Overloads->decls_end(); it != DeclsEnd; ++it) {
1322       OverloadSet.addDecl(*it);
1323 
1324       // Check whether the function is a non-template, non-member which takes no
1325       // arguments.
1326       if (IsMemExpr)
1327         continue;
1328       if (const FunctionDecl *OverloadDecl
1329             = dyn_cast<FunctionDecl>((*it)->getUnderlyingDecl())) {
1330         if (OverloadDecl->getMinRequiredArguments() == 0) {
1331           if (!ZeroArgCallReturnTy.isNull() && !Ambiguous) {
1332             ZeroArgCallReturnTy = QualType();
1333             Ambiguous = true;
1334           } else
1335             ZeroArgCallReturnTy = OverloadDecl->getReturnType();
1336         }
1337       }
1338     }
1339 
1340     // If it's not a member, use better machinery to try to resolve the call
1341     if (!IsMemExpr)
1342       return !ZeroArgCallReturnTy.isNull();
1343   }
1344 
1345   // Attempt to call the member with no arguments - this will correctly handle
1346   // member templates with defaults/deduction of template arguments, overloads
1347   // with default arguments, etc.
1348   if (IsMemExpr && !E.isTypeDependent()) {
1349     bool Suppress = getDiagnostics().getSuppressAllDiagnostics();
1350     getDiagnostics().setSuppressAllDiagnostics(true);
1351     ExprResult R = BuildCallToMemberFunction(nullptr, &E, SourceLocation(),
1352                                              None, SourceLocation());
1353     getDiagnostics().setSuppressAllDiagnostics(Suppress);
1354     if (R.isUsable()) {
1355       ZeroArgCallReturnTy = R.get()->getType();
1356       return true;
1357     }
1358     return false;
1359   }
1360 
1361   if (const DeclRefExpr *DeclRef = dyn_cast<DeclRefExpr>(E.IgnoreParens())) {
1362     if (const FunctionDecl *Fun = dyn_cast<FunctionDecl>(DeclRef->getDecl())) {
1363       if (Fun->getMinRequiredArguments() == 0)
1364         ZeroArgCallReturnTy = Fun->getReturnType();
1365       return true;
1366     }
1367   }
1368 
1369   // We don't have an expression that's convenient to get a FunctionDecl from,
1370   // but we can at least check if the type is "function of 0 arguments".
1371   QualType ExprTy = E.getType();
1372   const FunctionType *FunTy = nullptr;
1373   QualType PointeeTy = ExprTy->getPointeeType();
1374   if (!PointeeTy.isNull())
1375     FunTy = PointeeTy->getAs<FunctionType>();
1376   if (!FunTy)
1377     FunTy = ExprTy->getAs<FunctionType>();
1378 
1379   if (const FunctionProtoType *FPT =
1380       dyn_cast_or_null<FunctionProtoType>(FunTy)) {
1381     if (FPT->getNumParams() == 0)
1382       ZeroArgCallReturnTy = FunTy->getReturnType();
1383     return true;
1384   }
1385   return false;
1386 }
1387 
1388 /// \brief Give notes for a set of overloads.
1389 ///
1390 /// A companion to tryExprAsCall. In cases when the name that the programmer
1391 /// wrote was an overloaded function, we may be able to make some guesses about
1392 /// plausible overloads based on their return types; such guesses can be handed
1393 /// off to this method to be emitted as notes.
1394 ///
1395 /// \param Overloads - The overloads to note.
1396 /// \param FinalNoteLoc - If we've suppressed printing some overloads due to
1397 ///  -fshow-overloads=best, this is the location to attach to the note about too
1398 ///  many candidates. Typically this will be the location of the original
1399 ///  ill-formed expression.
noteOverloads(Sema & S,const UnresolvedSetImpl & Overloads,const SourceLocation FinalNoteLoc)1400 static void noteOverloads(Sema &S, const UnresolvedSetImpl &Overloads,
1401                           const SourceLocation FinalNoteLoc) {
1402   int ShownOverloads = 0;
1403   int SuppressedOverloads = 0;
1404   for (UnresolvedSetImpl::iterator It = Overloads.begin(),
1405        DeclsEnd = Overloads.end(); It != DeclsEnd; ++It) {
1406     // FIXME: Magic number for max shown overloads stolen from
1407     // OverloadCandidateSet::NoteCandidates.
1408     if (ShownOverloads >= 4 && S.Diags.getShowOverloads() == Ovl_Best) {
1409       ++SuppressedOverloads;
1410       continue;
1411     }
1412 
1413     NamedDecl *Fn = (*It)->getUnderlyingDecl();
1414     S.Diag(Fn->getLocation(), diag::note_possible_target_of_call);
1415     ++ShownOverloads;
1416   }
1417 
1418   if (SuppressedOverloads)
1419     S.Diag(FinalNoteLoc, diag::note_ovl_too_many_candidates)
1420       << SuppressedOverloads;
1421 }
1422 
notePlausibleOverloads(Sema & S,SourceLocation Loc,const UnresolvedSetImpl & Overloads,bool (* IsPlausibleResult)(QualType))1423 static void notePlausibleOverloads(Sema &S, SourceLocation Loc,
1424                                    const UnresolvedSetImpl &Overloads,
1425                                    bool (*IsPlausibleResult)(QualType)) {
1426   if (!IsPlausibleResult)
1427     return noteOverloads(S, Overloads, Loc);
1428 
1429   UnresolvedSet<2> PlausibleOverloads;
1430   for (OverloadExpr::decls_iterator It = Overloads.begin(),
1431          DeclsEnd = Overloads.end(); It != DeclsEnd; ++It) {
1432     const FunctionDecl *OverloadDecl = cast<FunctionDecl>(*It);
1433     QualType OverloadResultTy = OverloadDecl->getReturnType();
1434     if (IsPlausibleResult(OverloadResultTy))
1435       PlausibleOverloads.addDecl(It.getDecl());
1436   }
1437   noteOverloads(S, PlausibleOverloads, Loc);
1438 }
1439 
1440 /// Determine whether the given expression can be called by just
1441 /// putting parentheses after it.  Notably, expressions with unary
1442 /// operators can't be because the unary operator will start parsing
1443 /// outside the call.
IsCallableWithAppend(Expr * E)1444 static bool IsCallableWithAppend(Expr *E) {
1445   E = E->IgnoreImplicit();
1446   return (!isa<CStyleCastExpr>(E) &&
1447           !isa<UnaryOperator>(E) &&
1448           !isa<BinaryOperator>(E) &&
1449           !isa<CXXOperatorCallExpr>(E));
1450 }
1451 
tryToRecoverWithCall(ExprResult & E,const PartialDiagnostic & PD,bool ForceComplain,bool (* IsPlausibleResult)(QualType))1452 bool Sema::tryToRecoverWithCall(ExprResult &E, const PartialDiagnostic &PD,
1453                                 bool ForceComplain,
1454                                 bool (*IsPlausibleResult)(QualType)) {
1455   SourceLocation Loc = E.get()->getExprLoc();
1456   SourceRange Range = E.get()->getSourceRange();
1457 
1458   QualType ZeroArgCallTy;
1459   UnresolvedSet<4> Overloads;
1460   if (tryExprAsCall(*E.get(), ZeroArgCallTy, Overloads) &&
1461       !ZeroArgCallTy.isNull() &&
1462       (!IsPlausibleResult || IsPlausibleResult(ZeroArgCallTy))) {
1463     // At this point, we know E is potentially callable with 0
1464     // arguments and that it returns something of a reasonable type,
1465     // so we can emit a fixit and carry on pretending that E was
1466     // actually a CallExpr.
1467     SourceLocation ParenInsertionLoc = getLocForEndOfToken(Range.getEnd());
1468     Diag(Loc, PD)
1469       << /*zero-arg*/ 1 << Range
1470       << (IsCallableWithAppend(E.get())
1471           ? FixItHint::CreateInsertion(ParenInsertionLoc, "()")
1472           : FixItHint());
1473     notePlausibleOverloads(*this, Loc, Overloads, IsPlausibleResult);
1474 
1475     // FIXME: Try this before emitting the fixit, and suppress diagnostics
1476     // while doing so.
1477     E = ActOnCallExpr(nullptr, E.get(), Range.getEnd(), None,
1478                       Range.getEnd().getLocWithOffset(1));
1479     return true;
1480   }
1481 
1482   if (!ForceComplain) return false;
1483 
1484   Diag(Loc, PD) << /*not zero-arg*/ 0 << Range;
1485   notePlausibleOverloads(*this, Loc, Overloads, IsPlausibleResult);
1486   E = ExprError();
1487   return true;
1488 }
1489 
getSuperIdentifier() const1490 IdentifierInfo *Sema::getSuperIdentifier() const {
1491   if (!Ident_super)
1492     Ident_super = &Context.Idents.get("super");
1493   return Ident_super;
1494 }
1495 
getFloat128Identifier() const1496 IdentifierInfo *Sema::getFloat128Identifier() const {
1497   if (!Ident___float128)
1498     Ident___float128 = &Context.Idents.get("__float128");
1499   return Ident___float128;
1500 }
1501 
PushCapturedRegionScope(Scope * S,CapturedDecl * CD,RecordDecl * RD,CapturedRegionKind K)1502 void Sema::PushCapturedRegionScope(Scope *S, CapturedDecl *CD, RecordDecl *RD,
1503                                    CapturedRegionKind K) {
1504   CapturingScopeInfo *CSI = new CapturedRegionScopeInfo(
1505       getDiagnostics(), S, CD, RD, CD->getContextParam(), K,
1506       (getLangOpts().OpenMP && K == CR_OpenMP) ? getOpenMPNestingLevel() : 0);
1507   CSI->ReturnType = Context.VoidTy;
1508   FunctionScopes.push_back(CSI);
1509 }
1510 
getCurCapturedRegion()1511 CapturedRegionScopeInfo *Sema::getCurCapturedRegion() {
1512   if (FunctionScopes.empty())
1513     return nullptr;
1514 
1515   return dyn_cast<CapturedRegionScopeInfo>(FunctionScopes.back());
1516 }
1517 
1518 const llvm::MapVector<FieldDecl *, Sema::DeleteLocs> &
getMismatchingDeleteExpressions() const1519 Sema::getMismatchingDeleteExpressions() const {
1520   return DeleteExprs;
1521 }
1522