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1 //===--- SemaTemplateInstantiateDecl.cpp - C++ Template Decl Instantiation ===/
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 //  This file implements C++ template instantiation for declarations.
10 //
11 //===----------------------------------------------------------------------===/
12 #include "clang/Sema/SemaInternal.h"
13 #include "clang/AST/ASTConsumer.h"
14 #include "clang/AST/ASTContext.h"
15 #include "clang/AST/DeclTemplate.h"
16 #include "clang/AST/DeclVisitor.h"
17 #include "clang/AST/DependentDiagnostic.h"
18 #include "clang/AST/Expr.h"
19 #include "clang/AST/ExprCXX.h"
20 #include "clang/AST/TypeLoc.h"
21 #include "clang/Lex/Preprocessor.h"
22 #include "clang/Sema/Lookup.h"
23 #include "clang/Sema/PrettyDeclStackTrace.h"
24 #include "clang/Sema/Template.h"
25 
26 using namespace clang;
27 
SubstQualifier(const DeclaratorDecl * OldDecl,DeclaratorDecl * NewDecl)28 bool TemplateDeclInstantiator::SubstQualifier(const DeclaratorDecl *OldDecl,
29                                               DeclaratorDecl *NewDecl) {
30   if (!OldDecl->getQualifierLoc())
31     return false;
32 
33   NestedNameSpecifierLoc NewQualifierLoc
34     = SemaRef.SubstNestedNameSpecifierLoc(OldDecl->getQualifierLoc(),
35                                           TemplateArgs);
36 
37   if (!NewQualifierLoc)
38     return true;
39 
40   NewDecl->setQualifierInfo(NewQualifierLoc);
41   return false;
42 }
43 
SubstQualifier(const TagDecl * OldDecl,TagDecl * NewDecl)44 bool TemplateDeclInstantiator::SubstQualifier(const TagDecl *OldDecl,
45                                               TagDecl *NewDecl) {
46   if (!OldDecl->getQualifierLoc())
47     return false;
48 
49   NestedNameSpecifierLoc NewQualifierLoc
50   = SemaRef.SubstNestedNameSpecifierLoc(OldDecl->getQualifierLoc(),
51                                         TemplateArgs);
52 
53   if (!NewQualifierLoc)
54     return true;
55 
56   NewDecl->setQualifierInfo(NewQualifierLoc);
57   return false;
58 }
59 
60 // Include attribute instantiation code.
61 #include "clang/Sema/AttrTemplateInstantiate.inc"
62 
instantiateDependentAlignedAttr(Sema & S,const MultiLevelTemplateArgumentList & TemplateArgs,const AlignedAttr * Aligned,Decl * New,bool IsPackExpansion)63 static void instantiateDependentAlignedAttr(
64     Sema &S, const MultiLevelTemplateArgumentList &TemplateArgs,
65     const AlignedAttr *Aligned, Decl *New, bool IsPackExpansion) {
66   if (Aligned->isAlignmentExpr()) {
67     // The alignment expression is a constant expression.
68     EnterExpressionEvaluationContext Unevaluated(S, Sema::ConstantEvaluated);
69     ExprResult Result = S.SubstExpr(Aligned->getAlignmentExpr(), TemplateArgs);
70     if (!Result.isInvalid())
71       S.AddAlignedAttr(Aligned->getLocation(), New, Result.takeAs<Expr>(),
72                        Aligned->getSpellingListIndex(), IsPackExpansion);
73   } else {
74     TypeSourceInfo *Result = S.SubstType(Aligned->getAlignmentType(),
75                                          TemplateArgs, Aligned->getLocation(),
76                                          DeclarationName());
77     if (Result)
78       S.AddAlignedAttr(Aligned->getLocation(), New, Result,
79                        Aligned->getSpellingListIndex(), IsPackExpansion);
80   }
81 }
82 
instantiateDependentAlignedAttr(Sema & S,const MultiLevelTemplateArgumentList & TemplateArgs,const AlignedAttr * Aligned,Decl * New)83 static void instantiateDependentAlignedAttr(
84     Sema &S, const MultiLevelTemplateArgumentList &TemplateArgs,
85     const AlignedAttr *Aligned, Decl *New) {
86   if (!Aligned->isPackExpansion()) {
87     instantiateDependentAlignedAttr(S, TemplateArgs, Aligned, New, false);
88     return;
89   }
90 
91   SmallVector<UnexpandedParameterPack, 2> Unexpanded;
92   if (Aligned->isAlignmentExpr())
93     S.collectUnexpandedParameterPacks(Aligned->getAlignmentExpr(),
94                                       Unexpanded);
95   else
96     S.collectUnexpandedParameterPacks(Aligned->getAlignmentType()->getTypeLoc(),
97                                       Unexpanded);
98   assert(!Unexpanded.empty() && "Pack expansion without parameter packs?");
99 
100   // Determine whether we can expand this attribute pack yet.
101   bool Expand = true, RetainExpansion = false;
102   Optional<unsigned> NumExpansions;
103   // FIXME: Use the actual location of the ellipsis.
104   SourceLocation EllipsisLoc = Aligned->getLocation();
105   if (S.CheckParameterPacksForExpansion(EllipsisLoc, Aligned->getRange(),
106                                         Unexpanded, TemplateArgs, Expand,
107                                         RetainExpansion, NumExpansions))
108     return;
109 
110   if (!Expand) {
111     Sema::ArgumentPackSubstitutionIndexRAII SubstIndex(S, -1);
112     instantiateDependentAlignedAttr(S, TemplateArgs, Aligned, New, true);
113   } else {
114     for (unsigned I = 0; I != *NumExpansions; ++I) {
115       Sema::ArgumentPackSubstitutionIndexRAII SubstIndex(S, I);
116       instantiateDependentAlignedAttr(S, TemplateArgs, Aligned, New, false);
117     }
118   }
119 }
120 
InstantiateAttrs(const MultiLevelTemplateArgumentList & TemplateArgs,const Decl * Tmpl,Decl * New,LateInstantiatedAttrVec * LateAttrs,LocalInstantiationScope * OuterMostScope)121 void Sema::InstantiateAttrs(const MultiLevelTemplateArgumentList &TemplateArgs,
122                             const Decl *Tmpl, Decl *New,
123                             LateInstantiatedAttrVec *LateAttrs,
124                             LocalInstantiationScope *OuterMostScope) {
125   for (AttrVec::const_iterator i = Tmpl->attr_begin(), e = Tmpl->attr_end();
126        i != e; ++i) {
127     const Attr *TmplAttr = *i;
128 
129     // FIXME: This should be generalized to more than just the AlignedAttr.
130     const AlignedAttr *Aligned = dyn_cast<AlignedAttr>(TmplAttr);
131     if (Aligned && Aligned->isAlignmentDependent()) {
132       instantiateDependentAlignedAttr(*this, TemplateArgs, Aligned, New);
133       continue;
134     }
135 
136     assert(!TmplAttr->isPackExpansion());
137     if (TmplAttr->isLateParsed() && LateAttrs) {
138       // Late parsed attributes must be instantiated and attached after the
139       // enclosing class has been instantiated.  See Sema::InstantiateClass.
140       LocalInstantiationScope *Saved = 0;
141       if (CurrentInstantiationScope)
142         Saved = CurrentInstantiationScope->cloneScopes(OuterMostScope);
143       LateAttrs->push_back(LateInstantiatedAttribute(TmplAttr, Saved, New));
144     } else {
145       Attr *NewAttr = sema::instantiateTemplateAttribute(TmplAttr, Context,
146                                                          *this, TemplateArgs);
147       if (NewAttr)
148         New->addAttr(NewAttr);
149     }
150   }
151 }
152 
153 Decl *
VisitTranslationUnitDecl(TranslationUnitDecl * D)154 TemplateDeclInstantiator::VisitTranslationUnitDecl(TranslationUnitDecl *D) {
155   llvm_unreachable("Translation units cannot be instantiated");
156 }
157 
158 Decl *
VisitLabelDecl(LabelDecl * D)159 TemplateDeclInstantiator::VisitLabelDecl(LabelDecl *D) {
160   LabelDecl *Inst = LabelDecl::Create(SemaRef.Context, Owner, D->getLocation(),
161                                       D->getIdentifier());
162   Owner->addDecl(Inst);
163   return Inst;
164 }
165 
166 Decl *
VisitNamespaceDecl(NamespaceDecl * D)167 TemplateDeclInstantiator::VisitNamespaceDecl(NamespaceDecl *D) {
168   llvm_unreachable("Namespaces cannot be instantiated");
169 }
170 
171 Decl *
VisitNamespaceAliasDecl(NamespaceAliasDecl * D)172 TemplateDeclInstantiator::VisitNamespaceAliasDecl(NamespaceAliasDecl *D) {
173   NamespaceAliasDecl *Inst
174     = NamespaceAliasDecl::Create(SemaRef.Context, Owner,
175                                  D->getNamespaceLoc(),
176                                  D->getAliasLoc(),
177                                  D->getIdentifier(),
178                                  D->getQualifierLoc(),
179                                  D->getTargetNameLoc(),
180                                  D->getNamespace());
181   Owner->addDecl(Inst);
182   return Inst;
183 }
184 
InstantiateTypedefNameDecl(TypedefNameDecl * D,bool IsTypeAlias)185 Decl *TemplateDeclInstantiator::InstantiateTypedefNameDecl(TypedefNameDecl *D,
186                                                            bool IsTypeAlias) {
187   bool Invalid = false;
188   TypeSourceInfo *DI = D->getTypeSourceInfo();
189   if (DI->getType()->isInstantiationDependentType() ||
190       DI->getType()->isVariablyModifiedType()) {
191     DI = SemaRef.SubstType(DI, TemplateArgs,
192                            D->getLocation(), D->getDeclName());
193     if (!DI) {
194       Invalid = true;
195       DI = SemaRef.Context.getTrivialTypeSourceInfo(SemaRef.Context.IntTy);
196     }
197   } else {
198     SemaRef.MarkDeclarationsReferencedInType(D->getLocation(), DI->getType());
199   }
200 
201   // HACK: g++ has a bug where it gets the value kind of ?: wrong.
202   // libstdc++ relies upon this bug in its implementation of common_type.
203   // If we happen to be processing that implementation, fake up the g++ ?:
204   // semantics. See LWG issue 2141 for more information on the bug.
205   const DecltypeType *DT = DI->getType()->getAs<DecltypeType>();
206   CXXRecordDecl *RD = dyn_cast<CXXRecordDecl>(D->getDeclContext());
207   if (DT && RD && isa<ConditionalOperator>(DT->getUnderlyingExpr()) &&
208       DT->isReferenceType() &&
209       RD->getEnclosingNamespaceContext() == SemaRef.getStdNamespace() &&
210       RD->getIdentifier() && RD->getIdentifier()->isStr("common_type") &&
211       D->getIdentifier() && D->getIdentifier()->isStr("type") &&
212       SemaRef.getSourceManager().isInSystemHeader(D->getLocStart()))
213     // Fold it to the (non-reference) type which g++ would have produced.
214     DI = SemaRef.Context.getTrivialTypeSourceInfo(
215       DI->getType().getNonReferenceType());
216 
217   // Create the new typedef
218   TypedefNameDecl *Typedef;
219   if (IsTypeAlias)
220     Typedef = TypeAliasDecl::Create(SemaRef.Context, Owner, D->getLocStart(),
221                                     D->getLocation(), D->getIdentifier(), DI);
222   else
223     Typedef = TypedefDecl::Create(SemaRef.Context, Owner, D->getLocStart(),
224                                   D->getLocation(), D->getIdentifier(), DI);
225   if (Invalid)
226     Typedef->setInvalidDecl();
227 
228   // If the old typedef was the name for linkage purposes of an anonymous
229   // tag decl, re-establish that relationship for the new typedef.
230   if (const TagType *oldTagType = D->getUnderlyingType()->getAs<TagType>()) {
231     TagDecl *oldTag = oldTagType->getDecl();
232     if (oldTag->getTypedefNameForAnonDecl() == D && !Invalid) {
233       TagDecl *newTag = DI->getType()->castAs<TagType>()->getDecl();
234       assert(!newTag->hasNameForLinkage());
235       newTag->setTypedefNameForAnonDecl(Typedef);
236     }
237   }
238 
239   if (TypedefNameDecl *Prev = D->getPreviousDecl()) {
240     NamedDecl *InstPrev = SemaRef.FindInstantiatedDecl(D->getLocation(), Prev,
241                                                        TemplateArgs);
242     if (!InstPrev)
243       return 0;
244 
245     TypedefNameDecl *InstPrevTypedef = cast<TypedefNameDecl>(InstPrev);
246 
247     // If the typedef types are not identical, reject them.
248     SemaRef.isIncompatibleTypedef(InstPrevTypedef, Typedef);
249 
250     Typedef->setPreviousDeclaration(InstPrevTypedef);
251   }
252 
253   SemaRef.InstantiateAttrs(TemplateArgs, D, Typedef);
254 
255   Typedef->setAccess(D->getAccess());
256 
257   return Typedef;
258 }
259 
VisitTypedefDecl(TypedefDecl * D)260 Decl *TemplateDeclInstantiator::VisitTypedefDecl(TypedefDecl *D) {
261   Decl *Typedef = InstantiateTypedefNameDecl(D, /*IsTypeAlias=*/false);
262   Owner->addDecl(Typedef);
263   return Typedef;
264 }
265 
VisitTypeAliasDecl(TypeAliasDecl * D)266 Decl *TemplateDeclInstantiator::VisitTypeAliasDecl(TypeAliasDecl *D) {
267   Decl *Typedef = InstantiateTypedefNameDecl(D, /*IsTypeAlias=*/true);
268   Owner->addDecl(Typedef);
269   return Typedef;
270 }
271 
272 Decl *
VisitTypeAliasTemplateDecl(TypeAliasTemplateDecl * D)273 TemplateDeclInstantiator::VisitTypeAliasTemplateDecl(TypeAliasTemplateDecl *D) {
274   // Create a local instantiation scope for this type alias template, which
275   // will contain the instantiations of the template parameters.
276   LocalInstantiationScope Scope(SemaRef);
277 
278   TemplateParameterList *TempParams = D->getTemplateParameters();
279   TemplateParameterList *InstParams = SubstTemplateParams(TempParams);
280   if (!InstParams)
281     return 0;
282 
283   TypeAliasDecl *Pattern = D->getTemplatedDecl();
284 
285   TypeAliasTemplateDecl *PrevAliasTemplate = 0;
286   if (Pattern->getPreviousDecl()) {
287     DeclContext::lookup_result Found = Owner->lookup(Pattern->getDeclName());
288     if (!Found.empty()) {
289       PrevAliasTemplate = dyn_cast<TypeAliasTemplateDecl>(Found.front());
290     }
291   }
292 
293   TypeAliasDecl *AliasInst = cast_or_null<TypeAliasDecl>(
294     InstantiateTypedefNameDecl(Pattern, /*IsTypeAlias=*/true));
295   if (!AliasInst)
296     return 0;
297 
298   TypeAliasTemplateDecl *Inst
299     = TypeAliasTemplateDecl::Create(SemaRef.Context, Owner, D->getLocation(),
300                                     D->getDeclName(), InstParams, AliasInst);
301   if (PrevAliasTemplate)
302     Inst->setPreviousDeclaration(PrevAliasTemplate);
303 
304   Inst->setAccess(D->getAccess());
305 
306   if (!PrevAliasTemplate)
307     Inst->setInstantiatedFromMemberTemplate(D);
308 
309   Owner->addDecl(Inst);
310 
311   return Inst;
312 }
313 
VisitVarDecl(VarDecl * D)314 Decl *TemplateDeclInstantiator::VisitVarDecl(VarDecl *D) {
315   // If this is the variable for an anonymous struct or union,
316   // instantiate the anonymous struct/union type first.
317   if (const RecordType *RecordTy = D->getType()->getAs<RecordType>())
318     if (RecordTy->getDecl()->isAnonymousStructOrUnion())
319       if (!VisitCXXRecordDecl(cast<CXXRecordDecl>(RecordTy->getDecl())))
320         return 0;
321 
322   // Do substitution on the type of the declaration
323   TypeSourceInfo *DI = SemaRef.SubstType(D->getTypeSourceInfo(),
324                                          TemplateArgs,
325                                          D->getTypeSpecStartLoc(),
326                                          D->getDeclName());
327   if (!DI)
328     return 0;
329 
330   if (DI->getType()->isFunctionType()) {
331     SemaRef.Diag(D->getLocation(), diag::err_variable_instantiates_to_function)
332       << D->isStaticDataMember() << DI->getType();
333     return 0;
334   }
335 
336   // Build the instantiated declaration
337   VarDecl *Var = VarDecl::Create(SemaRef.Context, Owner,
338                                  D->getInnerLocStart(),
339                                  D->getLocation(), D->getIdentifier(),
340                                  DI->getType(), DI,
341                                  D->getStorageClass(),
342                                  D->getStorageClassAsWritten());
343   Var->setThreadSpecified(D->isThreadSpecified());
344   Var->setInitStyle(D->getInitStyle());
345   Var->setCXXForRangeDecl(D->isCXXForRangeDecl());
346   Var->setConstexpr(D->isConstexpr());
347 
348   // Substitute the nested name specifier, if any.
349   if (SubstQualifier(D, Var))
350     return 0;
351 
352   // If we are instantiating a static data member defined
353   // out-of-line, the instantiation will have the same lexical
354   // context (which will be a namespace scope) as the template.
355   if (D->isOutOfLine())
356     Var->setLexicalDeclContext(D->getLexicalDeclContext());
357 
358   Var->setAccess(D->getAccess());
359 
360   if (!D->isStaticDataMember()) {
361     Var->setUsed(D->isUsed(false));
362     Var->setReferenced(D->isReferenced());
363   }
364 
365   SemaRef.InstantiateAttrs(TemplateArgs, D, Var, LateAttrs, StartingScope);
366 
367   if (Var->hasAttrs())
368     SemaRef.CheckAlignasUnderalignment(Var);
369 
370   // FIXME: In theory, we could have a previous declaration for variables that
371   // are not static data members.
372   // FIXME: having to fake up a LookupResult is dumb.
373   LookupResult Previous(SemaRef, Var->getDeclName(), Var->getLocation(),
374                         Sema::LookupOrdinaryName, Sema::ForRedeclaration);
375   if (D->isStaticDataMember())
376     SemaRef.LookupQualifiedName(Previous, Owner, false);
377 
378   // In ARC, infer 'retaining' for variables of retainable type.
379   if (SemaRef.getLangOpts().ObjCAutoRefCount &&
380       SemaRef.inferObjCARCLifetime(Var))
381     Var->setInvalidDecl();
382 
383   SemaRef.CheckVariableDeclaration(Var, Previous);
384 
385   if (D->isOutOfLine()) {
386     D->getLexicalDeclContext()->addDecl(Var);
387     Owner->makeDeclVisibleInContext(Var);
388   } else {
389     Owner->addDecl(Var);
390     if (Owner->isFunctionOrMethod())
391       SemaRef.CurrentInstantiationScope->InstantiatedLocal(D, Var);
392   }
393 
394   // Link instantiations of static data members back to the template from
395   // which they were instantiated.
396   if (Var->isStaticDataMember())
397     SemaRef.Context.setInstantiatedFromStaticDataMember(Var, D,
398                                                      TSK_ImplicitInstantiation);
399 
400   if (Var->getAnyInitializer()) {
401     // We already have an initializer in the class.
402   } else if (D->getInit()) {
403     if (Var->isStaticDataMember() && !D->isOutOfLine())
404       SemaRef.PushExpressionEvaluationContext(Sema::ConstantEvaluated, D);
405     else
406       SemaRef.PushExpressionEvaluationContext(Sema::PotentiallyEvaluated, D);
407 
408     // Instantiate the initializer.
409     ExprResult Init = SemaRef.SubstInitializer(D->getInit(), TemplateArgs,
410                                         D->getInitStyle() == VarDecl::CallInit);
411     if (!Init.isInvalid()) {
412       bool TypeMayContainAuto = true;
413       if (Init.get()) {
414         bool DirectInit = D->isDirectInit();
415         SemaRef.AddInitializerToDecl(Var, Init.take(), DirectInit,
416                                      TypeMayContainAuto);
417       } else
418         SemaRef.ActOnUninitializedDecl(Var, TypeMayContainAuto);
419     } else {
420       // FIXME: Not too happy about invalidating the declaration
421       // because of a bogus initializer.
422       Var->setInvalidDecl();
423     }
424 
425     SemaRef.PopExpressionEvaluationContext();
426   } else if ((!Var->isStaticDataMember() || Var->isOutOfLine()) &&
427              !Var->isCXXForRangeDecl())
428     SemaRef.ActOnUninitializedDecl(Var, false);
429 
430   // Diagnose unused local variables with dependent types, where the diagnostic
431   // will have been deferred.
432   if (!Var->isInvalidDecl() && Owner->isFunctionOrMethod() && !Var->isUsed() &&
433       D->getType()->isDependentType())
434     SemaRef.DiagnoseUnusedDecl(Var);
435 
436   return Var;
437 }
438 
VisitAccessSpecDecl(AccessSpecDecl * D)439 Decl *TemplateDeclInstantiator::VisitAccessSpecDecl(AccessSpecDecl *D) {
440   AccessSpecDecl* AD
441     = AccessSpecDecl::Create(SemaRef.Context, D->getAccess(), Owner,
442                              D->getAccessSpecifierLoc(), D->getColonLoc());
443   Owner->addHiddenDecl(AD);
444   return AD;
445 }
446 
VisitFieldDecl(FieldDecl * D)447 Decl *TemplateDeclInstantiator::VisitFieldDecl(FieldDecl *D) {
448   bool Invalid = false;
449   TypeSourceInfo *DI = D->getTypeSourceInfo();
450   if (DI->getType()->isInstantiationDependentType() ||
451       DI->getType()->isVariablyModifiedType())  {
452     DI = SemaRef.SubstType(DI, TemplateArgs,
453                            D->getLocation(), D->getDeclName());
454     if (!DI) {
455       DI = D->getTypeSourceInfo();
456       Invalid = true;
457     } else if (DI->getType()->isFunctionType()) {
458       // C++ [temp.arg.type]p3:
459       //   If a declaration acquires a function type through a type
460       //   dependent on a template-parameter and this causes a
461       //   declaration that does not use the syntactic form of a
462       //   function declarator to have function type, the program is
463       //   ill-formed.
464       SemaRef.Diag(D->getLocation(), diag::err_field_instantiates_to_function)
465         << DI->getType();
466       Invalid = true;
467     }
468   } else {
469     SemaRef.MarkDeclarationsReferencedInType(D->getLocation(), DI->getType());
470   }
471 
472   Expr *BitWidth = D->getBitWidth();
473   if (Invalid)
474     BitWidth = 0;
475   else if (BitWidth) {
476     // The bit-width expression is a constant expression.
477     EnterExpressionEvaluationContext Unevaluated(SemaRef,
478                                                  Sema::ConstantEvaluated);
479 
480     ExprResult InstantiatedBitWidth
481       = SemaRef.SubstExpr(BitWidth, TemplateArgs);
482     if (InstantiatedBitWidth.isInvalid()) {
483       Invalid = true;
484       BitWidth = 0;
485     } else
486       BitWidth = InstantiatedBitWidth.takeAs<Expr>();
487   }
488 
489   FieldDecl *Field = SemaRef.CheckFieldDecl(D->getDeclName(),
490                                             DI->getType(), DI,
491                                             cast<RecordDecl>(Owner),
492                                             D->getLocation(),
493                                             D->isMutable(),
494                                             BitWidth,
495                                             D->getInClassInitStyle(),
496                                             D->getInnerLocStart(),
497                                             D->getAccess(),
498                                             0);
499   if (!Field) {
500     cast<Decl>(Owner)->setInvalidDecl();
501     return 0;
502   }
503 
504   SemaRef.InstantiateAttrs(TemplateArgs, D, Field, LateAttrs, StartingScope);
505 
506   if (Field->hasAttrs())
507     SemaRef.CheckAlignasUnderalignment(Field);
508 
509   if (Invalid)
510     Field->setInvalidDecl();
511 
512   if (!Field->getDeclName()) {
513     // Keep track of where this decl came from.
514     SemaRef.Context.setInstantiatedFromUnnamedFieldDecl(Field, D);
515   }
516   if (CXXRecordDecl *Parent= dyn_cast<CXXRecordDecl>(Field->getDeclContext())) {
517     if (Parent->isAnonymousStructOrUnion() &&
518         Parent->getRedeclContext()->isFunctionOrMethod())
519       SemaRef.CurrentInstantiationScope->InstantiatedLocal(D, Field);
520   }
521 
522   Field->setImplicit(D->isImplicit());
523   Field->setAccess(D->getAccess());
524   Owner->addDecl(Field);
525 
526   return Field;
527 }
528 
VisitIndirectFieldDecl(IndirectFieldDecl * D)529 Decl *TemplateDeclInstantiator::VisitIndirectFieldDecl(IndirectFieldDecl *D) {
530   NamedDecl **NamedChain =
531     new (SemaRef.Context)NamedDecl*[D->getChainingSize()];
532 
533   int i = 0;
534   for (IndirectFieldDecl::chain_iterator PI =
535        D->chain_begin(), PE = D->chain_end();
536        PI != PE; ++PI) {
537     NamedDecl *Next = SemaRef.FindInstantiatedDecl(D->getLocation(), *PI,
538                                               TemplateArgs);
539     if (!Next)
540       return 0;
541 
542     NamedChain[i++] = Next;
543   }
544 
545   QualType T = cast<FieldDecl>(NamedChain[i-1])->getType();
546   IndirectFieldDecl* IndirectField
547     = IndirectFieldDecl::Create(SemaRef.Context, Owner, D->getLocation(),
548                                 D->getIdentifier(), T,
549                                 NamedChain, D->getChainingSize());
550 
551 
552   IndirectField->setImplicit(D->isImplicit());
553   IndirectField->setAccess(D->getAccess());
554   Owner->addDecl(IndirectField);
555   return IndirectField;
556 }
557 
VisitFriendDecl(FriendDecl * D)558 Decl *TemplateDeclInstantiator::VisitFriendDecl(FriendDecl *D) {
559   // Handle friend type expressions by simply substituting template
560   // parameters into the pattern type and checking the result.
561   if (TypeSourceInfo *Ty = D->getFriendType()) {
562     TypeSourceInfo *InstTy;
563     // If this is an unsupported friend, don't bother substituting template
564     // arguments into it. The actual type referred to won't be used by any
565     // parts of Clang, and may not be valid for instantiating. Just use the
566     // same info for the instantiated friend.
567     if (D->isUnsupportedFriend()) {
568       InstTy = Ty;
569     } else {
570       InstTy = SemaRef.SubstType(Ty, TemplateArgs,
571                                  D->getLocation(), DeclarationName());
572     }
573     if (!InstTy)
574       return 0;
575 
576     FriendDecl *FD = SemaRef.CheckFriendTypeDecl(D->getLocStart(),
577                                                  D->getFriendLoc(), InstTy);
578     if (!FD)
579       return 0;
580 
581     FD->setAccess(AS_public);
582     FD->setUnsupportedFriend(D->isUnsupportedFriend());
583     Owner->addDecl(FD);
584     return FD;
585   }
586 
587   NamedDecl *ND = D->getFriendDecl();
588   assert(ND && "friend decl must be a decl or a type!");
589 
590   // All of the Visit implementations for the various potential friend
591   // declarations have to be carefully written to work for friend
592   // objects, with the most important detail being that the target
593   // decl should almost certainly not be placed in Owner.
594   Decl *NewND = Visit(ND);
595   if (!NewND) return 0;
596 
597   FriendDecl *FD =
598     FriendDecl::Create(SemaRef.Context, Owner, D->getLocation(),
599                        cast<NamedDecl>(NewND), D->getFriendLoc());
600   FD->setAccess(AS_public);
601   FD->setUnsupportedFriend(D->isUnsupportedFriend());
602   Owner->addDecl(FD);
603   return FD;
604 }
605 
VisitStaticAssertDecl(StaticAssertDecl * D)606 Decl *TemplateDeclInstantiator::VisitStaticAssertDecl(StaticAssertDecl *D) {
607   Expr *AssertExpr = D->getAssertExpr();
608 
609   // The expression in a static assertion is a constant expression.
610   EnterExpressionEvaluationContext Unevaluated(SemaRef,
611                                                Sema::ConstantEvaluated);
612 
613   ExprResult InstantiatedAssertExpr
614     = SemaRef.SubstExpr(AssertExpr, TemplateArgs);
615   if (InstantiatedAssertExpr.isInvalid())
616     return 0;
617 
618   return SemaRef.BuildStaticAssertDeclaration(D->getLocation(),
619                                               InstantiatedAssertExpr.get(),
620                                               D->getMessage(),
621                                               D->getRParenLoc(),
622                                               D->isFailed());
623 }
624 
VisitEnumDecl(EnumDecl * D)625 Decl *TemplateDeclInstantiator::VisitEnumDecl(EnumDecl *D) {
626   EnumDecl *PrevDecl = 0;
627   if (D->getPreviousDecl()) {
628     NamedDecl *Prev = SemaRef.FindInstantiatedDecl(D->getLocation(),
629                                                    D->getPreviousDecl(),
630                                                    TemplateArgs);
631     if (!Prev) return 0;
632     PrevDecl = cast<EnumDecl>(Prev);
633   }
634 
635   EnumDecl *Enum = EnumDecl::Create(SemaRef.Context, Owner, D->getLocStart(),
636                                     D->getLocation(), D->getIdentifier(),
637                                     PrevDecl, D->isScoped(),
638                                     D->isScopedUsingClassTag(), D->isFixed());
639   if (D->isFixed()) {
640     if (TypeSourceInfo *TI = D->getIntegerTypeSourceInfo()) {
641       // If we have type source information for the underlying type, it means it
642       // has been explicitly set by the user. Perform substitution on it before
643       // moving on.
644       SourceLocation UnderlyingLoc = TI->getTypeLoc().getBeginLoc();
645       TypeSourceInfo *NewTI = SemaRef.SubstType(TI, TemplateArgs, UnderlyingLoc,
646                                                 DeclarationName());
647       if (!NewTI || SemaRef.CheckEnumUnderlyingType(NewTI))
648         Enum->setIntegerType(SemaRef.Context.IntTy);
649       else
650         Enum->setIntegerTypeSourceInfo(NewTI);
651     } else {
652       assert(!D->getIntegerType()->isDependentType()
653              && "Dependent type without type source info");
654       Enum->setIntegerType(D->getIntegerType());
655     }
656   }
657 
658   SemaRef.InstantiateAttrs(TemplateArgs, D, Enum);
659 
660   Enum->setInstantiationOfMemberEnum(D, TSK_ImplicitInstantiation);
661   Enum->setAccess(D->getAccess());
662   if (SubstQualifier(D, Enum)) return 0;
663   Owner->addDecl(Enum);
664 
665   EnumDecl *Def = D->getDefinition();
666   if (Def && Def != D) {
667     // If this is an out-of-line definition of an enum member template, check
668     // that the underlying types match in the instantiation of both
669     // declarations.
670     if (TypeSourceInfo *TI = Def->getIntegerTypeSourceInfo()) {
671       SourceLocation UnderlyingLoc = TI->getTypeLoc().getBeginLoc();
672       QualType DefnUnderlying =
673         SemaRef.SubstType(TI->getType(), TemplateArgs,
674                           UnderlyingLoc, DeclarationName());
675       SemaRef.CheckEnumRedeclaration(Def->getLocation(), Def->isScoped(),
676                                      DefnUnderlying, Enum);
677     }
678   }
679 
680   if (D->getDeclContext()->isFunctionOrMethod())
681     SemaRef.CurrentInstantiationScope->InstantiatedLocal(D, Enum);
682 
683   // C++11 [temp.inst]p1: The implicit instantiation of a class template
684   // specialization causes the implicit instantiation of the declarations, but
685   // not the definitions of scoped member enumerations.
686   // FIXME: There appears to be no wording for what happens for an enum defined
687   // within a block scope, but we treat that much like a member template. Only
688   // instantiate the definition when visiting the definition in that case, since
689   // we will visit all redeclarations.
690   if (!Enum->isScoped() && Def &&
691       (!D->getDeclContext()->isFunctionOrMethod() || D->isCompleteDefinition()))
692     InstantiateEnumDefinition(Enum, Def);
693 
694   return Enum;
695 }
696 
InstantiateEnumDefinition(EnumDecl * Enum,EnumDecl * Pattern)697 void TemplateDeclInstantiator::InstantiateEnumDefinition(
698     EnumDecl *Enum, EnumDecl *Pattern) {
699   Enum->startDefinition();
700 
701   // Update the location to refer to the definition.
702   Enum->setLocation(Pattern->getLocation());
703 
704   SmallVector<Decl*, 4> Enumerators;
705 
706   EnumConstantDecl *LastEnumConst = 0;
707   for (EnumDecl::enumerator_iterator EC = Pattern->enumerator_begin(),
708          ECEnd = Pattern->enumerator_end();
709        EC != ECEnd; ++EC) {
710     // The specified value for the enumerator.
711     ExprResult Value = SemaRef.Owned((Expr *)0);
712     if (Expr *UninstValue = EC->getInitExpr()) {
713       // The enumerator's value expression is a constant expression.
714       EnterExpressionEvaluationContext Unevaluated(SemaRef,
715                                                    Sema::ConstantEvaluated);
716 
717       Value = SemaRef.SubstExpr(UninstValue, TemplateArgs);
718     }
719 
720     // Drop the initial value and continue.
721     bool isInvalid = false;
722     if (Value.isInvalid()) {
723       Value = SemaRef.Owned((Expr *)0);
724       isInvalid = true;
725     }
726 
727     EnumConstantDecl *EnumConst
728       = SemaRef.CheckEnumConstant(Enum, LastEnumConst,
729                                   EC->getLocation(), EC->getIdentifier(),
730                                   Value.get());
731 
732     if (isInvalid) {
733       if (EnumConst)
734         EnumConst->setInvalidDecl();
735       Enum->setInvalidDecl();
736     }
737 
738     if (EnumConst) {
739       SemaRef.InstantiateAttrs(TemplateArgs, *EC, EnumConst);
740 
741       EnumConst->setAccess(Enum->getAccess());
742       Enum->addDecl(EnumConst);
743       Enumerators.push_back(EnumConst);
744       LastEnumConst = EnumConst;
745 
746       if (Pattern->getDeclContext()->isFunctionOrMethod() &&
747           !Enum->isScoped()) {
748         // If the enumeration is within a function or method, record the enum
749         // constant as a local.
750         SemaRef.CurrentInstantiationScope->InstantiatedLocal(*EC, EnumConst);
751       }
752     }
753   }
754 
755   // FIXME: Fixup LBraceLoc
756   SemaRef.ActOnEnumBody(Enum->getLocation(), SourceLocation(),
757                         Enum->getRBraceLoc(), Enum,
758                         Enumerators.data(), Enumerators.size(),
759                         0, 0);
760 }
761 
VisitEnumConstantDecl(EnumConstantDecl * D)762 Decl *TemplateDeclInstantiator::VisitEnumConstantDecl(EnumConstantDecl *D) {
763   llvm_unreachable("EnumConstantDecls can only occur within EnumDecls.");
764 }
765 
VisitClassTemplateDecl(ClassTemplateDecl * D)766 Decl *TemplateDeclInstantiator::VisitClassTemplateDecl(ClassTemplateDecl *D) {
767   bool isFriend = (D->getFriendObjectKind() != Decl::FOK_None);
768 
769   // Create a local instantiation scope for this class template, which
770   // will contain the instantiations of the template parameters.
771   LocalInstantiationScope Scope(SemaRef);
772   TemplateParameterList *TempParams = D->getTemplateParameters();
773   TemplateParameterList *InstParams = SubstTemplateParams(TempParams);
774   if (!InstParams)
775     return NULL;
776 
777   CXXRecordDecl *Pattern = D->getTemplatedDecl();
778 
779   // Instantiate the qualifier.  We have to do this first in case
780   // we're a friend declaration, because if we are then we need to put
781   // the new declaration in the appropriate context.
782   NestedNameSpecifierLoc QualifierLoc = Pattern->getQualifierLoc();
783   if (QualifierLoc) {
784     QualifierLoc = SemaRef.SubstNestedNameSpecifierLoc(QualifierLoc,
785                                                        TemplateArgs);
786     if (!QualifierLoc)
787       return 0;
788   }
789 
790   CXXRecordDecl *PrevDecl = 0;
791   ClassTemplateDecl *PrevClassTemplate = 0;
792 
793   if (!isFriend && Pattern->getPreviousDecl()) {
794     DeclContext::lookup_result Found = Owner->lookup(Pattern->getDeclName());
795     if (!Found.empty()) {
796       PrevClassTemplate = dyn_cast<ClassTemplateDecl>(Found.front());
797       if (PrevClassTemplate)
798         PrevDecl = PrevClassTemplate->getTemplatedDecl();
799     }
800   }
801 
802   // If this isn't a friend, then it's a member template, in which
803   // case we just want to build the instantiation in the
804   // specialization.  If it is a friend, we want to build it in
805   // the appropriate context.
806   DeclContext *DC = Owner;
807   if (isFriend) {
808     if (QualifierLoc) {
809       CXXScopeSpec SS;
810       SS.Adopt(QualifierLoc);
811       DC = SemaRef.computeDeclContext(SS);
812       if (!DC) return 0;
813     } else {
814       DC = SemaRef.FindInstantiatedContext(Pattern->getLocation(),
815                                            Pattern->getDeclContext(),
816                                            TemplateArgs);
817     }
818 
819     // Look for a previous declaration of the template in the owning
820     // context.
821     LookupResult R(SemaRef, Pattern->getDeclName(), Pattern->getLocation(),
822                    Sema::LookupOrdinaryName, Sema::ForRedeclaration);
823     SemaRef.LookupQualifiedName(R, DC);
824 
825     if (R.isSingleResult()) {
826       PrevClassTemplate = R.getAsSingle<ClassTemplateDecl>();
827       if (PrevClassTemplate)
828         PrevDecl = PrevClassTemplate->getTemplatedDecl();
829     }
830 
831     if (!PrevClassTemplate && QualifierLoc) {
832       SemaRef.Diag(Pattern->getLocation(), diag::err_not_tag_in_scope)
833         << D->getTemplatedDecl()->getTagKind() << Pattern->getDeclName() << DC
834         << QualifierLoc.getSourceRange();
835       return 0;
836     }
837 
838     bool AdoptedPreviousTemplateParams = false;
839     if (PrevClassTemplate) {
840       bool Complain = true;
841 
842       // HACK: libstdc++ 4.2.1 contains an ill-formed friend class
843       // template for struct std::tr1::__detail::_Map_base, where the
844       // template parameters of the friend declaration don't match the
845       // template parameters of the original declaration. In this one
846       // case, we don't complain about the ill-formed friend
847       // declaration.
848       if (isFriend && Pattern->getIdentifier() &&
849           Pattern->getIdentifier()->isStr("_Map_base") &&
850           DC->isNamespace() &&
851           cast<NamespaceDecl>(DC)->getIdentifier() &&
852           cast<NamespaceDecl>(DC)->getIdentifier()->isStr("__detail")) {
853         DeclContext *DCParent = DC->getParent();
854         if (DCParent->isNamespace() &&
855             cast<NamespaceDecl>(DCParent)->getIdentifier() &&
856             cast<NamespaceDecl>(DCParent)->getIdentifier()->isStr("tr1")) {
857           DeclContext *DCParent2 = DCParent->getParent();
858           if (DCParent2->isNamespace() &&
859               cast<NamespaceDecl>(DCParent2)->getIdentifier() &&
860               cast<NamespaceDecl>(DCParent2)->getIdentifier()->isStr("std") &&
861               DCParent2->getParent()->isTranslationUnit())
862             Complain = false;
863         }
864       }
865 
866       TemplateParameterList *PrevParams
867         = PrevClassTemplate->getTemplateParameters();
868 
869       // Make sure the parameter lists match.
870       if (!SemaRef.TemplateParameterListsAreEqual(InstParams, PrevParams,
871                                                   Complain,
872                                                   Sema::TPL_TemplateMatch)) {
873         if (Complain)
874           return 0;
875 
876         AdoptedPreviousTemplateParams = true;
877         InstParams = PrevParams;
878       }
879 
880       // Do some additional validation, then merge default arguments
881       // from the existing declarations.
882       if (!AdoptedPreviousTemplateParams &&
883           SemaRef.CheckTemplateParameterList(InstParams, PrevParams,
884                                              Sema::TPC_ClassTemplate))
885         return 0;
886     }
887   }
888 
889   CXXRecordDecl *RecordInst
890     = CXXRecordDecl::Create(SemaRef.Context, Pattern->getTagKind(), DC,
891                             Pattern->getLocStart(), Pattern->getLocation(),
892                             Pattern->getIdentifier(), PrevDecl,
893                             /*DelayTypeCreation=*/true);
894 
895   if (QualifierLoc)
896     RecordInst->setQualifierInfo(QualifierLoc);
897 
898   ClassTemplateDecl *Inst
899     = ClassTemplateDecl::Create(SemaRef.Context, DC, D->getLocation(),
900                                 D->getIdentifier(), InstParams, RecordInst,
901                                 PrevClassTemplate);
902   RecordInst->setDescribedClassTemplate(Inst);
903 
904   if (isFriend) {
905     if (PrevClassTemplate)
906       Inst->setAccess(PrevClassTemplate->getAccess());
907     else
908       Inst->setAccess(D->getAccess());
909 
910     Inst->setObjectOfFriendDecl(PrevClassTemplate != 0);
911     // TODO: do we want to track the instantiation progeny of this
912     // friend target decl?
913   } else {
914     Inst->setAccess(D->getAccess());
915     if (!PrevClassTemplate)
916       Inst->setInstantiatedFromMemberTemplate(D);
917   }
918 
919   // Trigger creation of the type for the instantiation.
920   SemaRef.Context.getInjectedClassNameType(RecordInst,
921                                     Inst->getInjectedClassNameSpecialization());
922 
923   // Finish handling of friends.
924   if (isFriend) {
925     DC->makeDeclVisibleInContext(Inst);
926     Inst->setLexicalDeclContext(Owner);
927     RecordInst->setLexicalDeclContext(Owner);
928     return Inst;
929   }
930 
931   if (D->isOutOfLine()) {
932     Inst->setLexicalDeclContext(D->getLexicalDeclContext());
933     RecordInst->setLexicalDeclContext(D->getLexicalDeclContext());
934   }
935 
936   Owner->addDecl(Inst);
937 
938   if (!PrevClassTemplate) {
939     // Queue up any out-of-line partial specializations of this member
940     // class template; the client will force their instantiation once
941     // the enclosing class has been instantiated.
942     SmallVector<ClassTemplatePartialSpecializationDecl *, 4> PartialSpecs;
943     D->getPartialSpecializations(PartialSpecs);
944     for (unsigned I = 0, N = PartialSpecs.size(); I != N; ++I)
945       if (PartialSpecs[I]->isOutOfLine())
946         OutOfLinePartialSpecs.push_back(std::make_pair(Inst, PartialSpecs[I]));
947   }
948 
949   return Inst;
950 }
951 
952 Decl *
VisitClassTemplatePartialSpecializationDecl(ClassTemplatePartialSpecializationDecl * D)953 TemplateDeclInstantiator::VisitClassTemplatePartialSpecializationDecl(
954                                    ClassTemplatePartialSpecializationDecl *D) {
955   ClassTemplateDecl *ClassTemplate = D->getSpecializedTemplate();
956 
957   // Lookup the already-instantiated declaration in the instantiation
958   // of the class template and return that.
959   DeclContext::lookup_result Found
960     = Owner->lookup(ClassTemplate->getDeclName());
961   if (Found.empty())
962     return 0;
963 
964   ClassTemplateDecl *InstClassTemplate
965     = dyn_cast<ClassTemplateDecl>(Found.front());
966   if (!InstClassTemplate)
967     return 0;
968 
969   if (ClassTemplatePartialSpecializationDecl *Result
970         = InstClassTemplate->findPartialSpecInstantiatedFromMember(D))
971     return Result;
972 
973   return InstantiateClassTemplatePartialSpecialization(InstClassTemplate, D);
974 }
975 
976 Decl *
VisitFunctionTemplateDecl(FunctionTemplateDecl * D)977 TemplateDeclInstantiator::VisitFunctionTemplateDecl(FunctionTemplateDecl *D) {
978   // Create a local instantiation scope for this function template, which
979   // will contain the instantiations of the template parameters and then get
980   // merged with the local instantiation scope for the function template
981   // itself.
982   LocalInstantiationScope Scope(SemaRef);
983 
984   TemplateParameterList *TempParams = D->getTemplateParameters();
985   TemplateParameterList *InstParams = SubstTemplateParams(TempParams);
986   if (!InstParams)
987     return NULL;
988 
989   FunctionDecl *Instantiated = 0;
990   if (CXXMethodDecl *DMethod = dyn_cast<CXXMethodDecl>(D->getTemplatedDecl()))
991     Instantiated = cast_or_null<FunctionDecl>(VisitCXXMethodDecl(DMethod,
992                                                                  InstParams));
993   else
994     Instantiated = cast_or_null<FunctionDecl>(VisitFunctionDecl(
995                                                           D->getTemplatedDecl(),
996                                                                 InstParams));
997 
998   if (!Instantiated)
999     return 0;
1000 
1001   // Link the instantiated function template declaration to the function
1002   // template from which it was instantiated.
1003   FunctionTemplateDecl *InstTemplate
1004     = Instantiated->getDescribedFunctionTemplate();
1005   InstTemplate->setAccess(D->getAccess());
1006   assert(InstTemplate &&
1007          "VisitFunctionDecl/CXXMethodDecl didn't create a template!");
1008 
1009   bool isFriend = (InstTemplate->getFriendObjectKind() != Decl::FOK_None);
1010 
1011   // Link the instantiation back to the pattern *unless* this is a
1012   // non-definition friend declaration.
1013   if (!InstTemplate->getInstantiatedFromMemberTemplate() &&
1014       !(isFriend && !D->getTemplatedDecl()->isThisDeclarationADefinition()))
1015     InstTemplate->setInstantiatedFromMemberTemplate(D);
1016 
1017   // Make declarations visible in the appropriate context.
1018   if (!isFriend) {
1019     Owner->addDecl(InstTemplate);
1020   } else if (InstTemplate->getDeclContext()->isRecord() &&
1021              !D->getPreviousDecl()) {
1022     SemaRef.CheckFriendAccess(InstTemplate);
1023   }
1024 
1025   return InstTemplate;
1026 }
1027 
VisitCXXRecordDecl(CXXRecordDecl * D)1028 Decl *TemplateDeclInstantiator::VisitCXXRecordDecl(CXXRecordDecl *D) {
1029   CXXRecordDecl *PrevDecl = 0;
1030   if (D->isInjectedClassName())
1031     PrevDecl = cast<CXXRecordDecl>(Owner);
1032   else if (D->getPreviousDecl()) {
1033     NamedDecl *Prev = SemaRef.FindInstantiatedDecl(D->getLocation(),
1034                                                    D->getPreviousDecl(),
1035                                                    TemplateArgs);
1036     if (!Prev) return 0;
1037     PrevDecl = cast<CXXRecordDecl>(Prev);
1038   }
1039 
1040   CXXRecordDecl *Record
1041     = CXXRecordDecl::Create(SemaRef.Context, D->getTagKind(), Owner,
1042                             D->getLocStart(), D->getLocation(),
1043                             D->getIdentifier(), PrevDecl);
1044 
1045   // Substitute the nested name specifier, if any.
1046   if (SubstQualifier(D, Record))
1047     return 0;
1048 
1049   Record->setImplicit(D->isImplicit());
1050   // FIXME: Check against AS_none is an ugly hack to work around the issue that
1051   // the tag decls introduced by friend class declarations don't have an access
1052   // specifier. Remove once this area of the code gets sorted out.
1053   if (D->getAccess() != AS_none)
1054     Record->setAccess(D->getAccess());
1055   if (!D->isInjectedClassName())
1056     Record->setInstantiationOfMemberClass(D, TSK_ImplicitInstantiation);
1057 
1058   // If the original function was part of a friend declaration,
1059   // inherit its namespace state.
1060   if (Decl::FriendObjectKind FOK = D->getFriendObjectKind())
1061     Record->setObjectOfFriendDecl(FOK == Decl::FOK_Declared);
1062 
1063   // Make sure that anonymous structs and unions are recorded.
1064   if (D->isAnonymousStructOrUnion()) {
1065     Record->setAnonymousStructOrUnion(true);
1066     if (Record->getDeclContext()->getRedeclContext()->isFunctionOrMethod())
1067       SemaRef.CurrentInstantiationScope->InstantiatedLocal(D, Record);
1068   }
1069 
1070   Owner->addDecl(Record);
1071   return Record;
1072 }
1073 
1074 /// \brief Adjust the given function type for an instantiation of the
1075 /// given declaration, to cope with modifications to the function's type that
1076 /// aren't reflected in the type-source information.
1077 ///
1078 /// \param D The declaration we're instantiating.
1079 /// \param TInfo The already-instantiated type.
adjustFunctionTypeForInstantiation(ASTContext & Context,FunctionDecl * D,TypeSourceInfo * TInfo)1080 static QualType adjustFunctionTypeForInstantiation(ASTContext &Context,
1081                                                    FunctionDecl *D,
1082                                                    TypeSourceInfo *TInfo) {
1083   const FunctionProtoType *OrigFunc
1084     = D->getType()->castAs<FunctionProtoType>();
1085   const FunctionProtoType *NewFunc
1086     = TInfo->getType()->castAs<FunctionProtoType>();
1087   if (OrigFunc->getExtInfo() == NewFunc->getExtInfo())
1088     return TInfo->getType();
1089 
1090   FunctionProtoType::ExtProtoInfo NewEPI = NewFunc->getExtProtoInfo();
1091   NewEPI.ExtInfo = OrigFunc->getExtInfo();
1092   return Context.getFunctionType(NewFunc->getResultType(),
1093                                  ArrayRef<QualType>(NewFunc->arg_type_begin(),
1094                                                     NewFunc->getNumArgs()),
1095                                  NewEPI);
1096 }
1097 
1098 /// Normal class members are of more specific types and therefore
1099 /// don't make it here.  This function serves two purposes:
1100 ///   1) instantiating function templates
1101 ///   2) substituting friend declarations
1102 /// FIXME: preserve function definitions in case #2
VisitFunctionDecl(FunctionDecl * D,TemplateParameterList * TemplateParams)1103 Decl *TemplateDeclInstantiator::VisitFunctionDecl(FunctionDecl *D,
1104                                        TemplateParameterList *TemplateParams) {
1105   // Check whether there is already a function template specialization for
1106   // this declaration.
1107   FunctionTemplateDecl *FunctionTemplate = D->getDescribedFunctionTemplate();
1108   if (FunctionTemplate && !TemplateParams) {
1109     std::pair<const TemplateArgument *, unsigned> Innermost
1110       = TemplateArgs.getInnermost();
1111 
1112     void *InsertPos = 0;
1113     FunctionDecl *SpecFunc
1114       = FunctionTemplate->findSpecialization(Innermost.first, Innermost.second,
1115                                              InsertPos);
1116 
1117     // If we already have a function template specialization, return it.
1118     if (SpecFunc)
1119       return SpecFunc;
1120   }
1121 
1122   bool isFriend;
1123   if (FunctionTemplate)
1124     isFriend = (FunctionTemplate->getFriendObjectKind() != Decl::FOK_None);
1125   else
1126     isFriend = (D->getFriendObjectKind() != Decl::FOK_None);
1127 
1128   bool MergeWithParentScope = (TemplateParams != 0) ||
1129     Owner->isFunctionOrMethod() ||
1130     !(isa<Decl>(Owner) &&
1131       cast<Decl>(Owner)->isDefinedOutsideFunctionOrMethod());
1132   LocalInstantiationScope Scope(SemaRef, MergeWithParentScope);
1133 
1134   SmallVector<ParmVarDecl *, 4> Params;
1135   TypeSourceInfo *TInfo = SubstFunctionType(D, Params);
1136   if (!TInfo)
1137     return 0;
1138   QualType T = adjustFunctionTypeForInstantiation(SemaRef.Context, D, TInfo);
1139 
1140   NestedNameSpecifierLoc QualifierLoc = D->getQualifierLoc();
1141   if (QualifierLoc) {
1142     QualifierLoc = SemaRef.SubstNestedNameSpecifierLoc(QualifierLoc,
1143                                                        TemplateArgs);
1144     if (!QualifierLoc)
1145       return 0;
1146   }
1147 
1148   // If we're instantiating a local function declaration, put the result
1149   // in the owner;  otherwise we need to find the instantiated context.
1150   DeclContext *DC;
1151   if (D->getDeclContext()->isFunctionOrMethod())
1152     DC = Owner;
1153   else if (isFriend && QualifierLoc) {
1154     CXXScopeSpec SS;
1155     SS.Adopt(QualifierLoc);
1156     DC = SemaRef.computeDeclContext(SS);
1157     if (!DC) return 0;
1158   } else {
1159     DC = SemaRef.FindInstantiatedContext(D->getLocation(), D->getDeclContext(),
1160                                          TemplateArgs);
1161   }
1162 
1163   FunctionDecl *Function =
1164       FunctionDecl::Create(SemaRef.Context, DC, D->getInnerLocStart(),
1165                            D->getNameInfo(), T, TInfo,
1166                            D->getStorageClass(), D->getStorageClassAsWritten(),
1167                            D->isInlineSpecified(), D->hasWrittenPrototype(),
1168                            D->isConstexpr());
1169 
1170   if (D->isInlined())
1171     Function->setImplicitlyInline();
1172 
1173   if (QualifierLoc)
1174     Function->setQualifierInfo(QualifierLoc);
1175 
1176   DeclContext *LexicalDC = Owner;
1177   if (!isFriend && D->isOutOfLine()) {
1178     assert(D->getDeclContext()->isFileContext());
1179     LexicalDC = D->getDeclContext();
1180   }
1181 
1182   Function->setLexicalDeclContext(LexicalDC);
1183 
1184   // Attach the parameters
1185   if (isa<FunctionProtoType>(Function->getType().IgnoreParens())) {
1186     // Adopt the already-instantiated parameters into our own context.
1187     for (unsigned P = 0; P < Params.size(); ++P)
1188       if (Params[P])
1189         Params[P]->setOwningFunction(Function);
1190   } else {
1191     // Since we were instantiated via a typedef of a function type, create
1192     // new parameters.
1193     const FunctionProtoType *Proto
1194       = Function->getType()->getAs<FunctionProtoType>();
1195     assert(Proto && "No function prototype in template instantiation?");
1196     for (FunctionProtoType::arg_type_iterator AI = Proto->arg_type_begin(),
1197          AE = Proto->arg_type_end(); AI != AE; ++AI) {
1198       ParmVarDecl *Param
1199         = SemaRef.BuildParmVarDeclForTypedef(Function, Function->getLocation(),
1200                                              *AI);
1201       Param->setScopeInfo(0, Params.size());
1202       Params.push_back(Param);
1203     }
1204   }
1205   Function->setParams(Params);
1206 
1207   SourceLocation InstantiateAtPOI;
1208   if (TemplateParams) {
1209     // Our resulting instantiation is actually a function template, since we
1210     // are substituting only the outer template parameters. For example, given
1211     //
1212     //   template<typename T>
1213     //   struct X {
1214     //     template<typename U> friend void f(T, U);
1215     //   };
1216     //
1217     //   X<int> x;
1218     //
1219     // We are instantiating the friend function template "f" within X<int>,
1220     // which means substituting int for T, but leaving "f" as a friend function
1221     // template.
1222     // Build the function template itself.
1223     FunctionTemplate = FunctionTemplateDecl::Create(SemaRef.Context, DC,
1224                                                     Function->getLocation(),
1225                                                     Function->getDeclName(),
1226                                                     TemplateParams, Function);
1227     Function->setDescribedFunctionTemplate(FunctionTemplate);
1228 
1229     FunctionTemplate->setLexicalDeclContext(LexicalDC);
1230 
1231     if (isFriend && D->isThisDeclarationADefinition()) {
1232       // TODO: should we remember this connection regardless of whether
1233       // the friend declaration provided a body?
1234       FunctionTemplate->setInstantiatedFromMemberTemplate(
1235                                            D->getDescribedFunctionTemplate());
1236     }
1237   } else if (FunctionTemplate) {
1238     // Record this function template specialization.
1239     std::pair<const TemplateArgument *, unsigned> Innermost
1240       = TemplateArgs.getInnermost();
1241     Function->setFunctionTemplateSpecialization(FunctionTemplate,
1242                             TemplateArgumentList::CreateCopy(SemaRef.Context,
1243                                                              Innermost.first,
1244                                                              Innermost.second),
1245                                                 /*InsertPos=*/0);
1246   } else if (isFriend) {
1247     // Note, we need this connection even if the friend doesn't have a body.
1248     // Its body may exist but not have been attached yet due to deferred
1249     // parsing.
1250     // FIXME: It might be cleaner to set this when attaching the body to the
1251     // friend function declaration, however that would require finding all the
1252     // instantiations and modifying them.
1253     Function->setInstantiationOfMemberFunction(D, TSK_ImplicitInstantiation);
1254   }
1255 
1256   if (InitFunctionInstantiation(Function, D))
1257     Function->setInvalidDecl();
1258 
1259   bool isExplicitSpecialization = false;
1260 
1261   LookupResult Previous(SemaRef, Function->getDeclName(), SourceLocation(),
1262                         Sema::LookupOrdinaryName, Sema::ForRedeclaration);
1263 
1264   if (DependentFunctionTemplateSpecializationInfo *Info
1265         = D->getDependentSpecializationInfo()) {
1266     assert(isFriend && "non-friend has dependent specialization info?");
1267 
1268     // This needs to be set now for future sanity.
1269     Function->setObjectOfFriendDecl(/*HasPrevious*/ true);
1270 
1271     // Instantiate the explicit template arguments.
1272     TemplateArgumentListInfo ExplicitArgs(Info->getLAngleLoc(),
1273                                           Info->getRAngleLoc());
1274     if (SemaRef.Subst(Info->getTemplateArgs(), Info->getNumTemplateArgs(),
1275                       ExplicitArgs, TemplateArgs))
1276       return 0;
1277 
1278     // Map the candidate templates to their instantiations.
1279     for (unsigned I = 0, E = Info->getNumTemplates(); I != E; ++I) {
1280       Decl *Temp = SemaRef.FindInstantiatedDecl(D->getLocation(),
1281                                                 Info->getTemplate(I),
1282                                                 TemplateArgs);
1283       if (!Temp) return 0;
1284 
1285       Previous.addDecl(cast<FunctionTemplateDecl>(Temp));
1286     }
1287 
1288     if (SemaRef.CheckFunctionTemplateSpecialization(Function,
1289                                                     &ExplicitArgs,
1290                                                     Previous))
1291       Function->setInvalidDecl();
1292 
1293     isExplicitSpecialization = true;
1294 
1295   } else if (TemplateParams || !FunctionTemplate) {
1296     // Look only into the namespace where the friend would be declared to
1297     // find a previous declaration. This is the innermost enclosing namespace,
1298     // as described in ActOnFriendFunctionDecl.
1299     SemaRef.LookupQualifiedName(Previous, DC);
1300 
1301     // In C++, the previous declaration we find might be a tag type
1302     // (class or enum). In this case, the new declaration will hide the
1303     // tag type. Note that this does does not apply if we're declaring a
1304     // typedef (C++ [dcl.typedef]p4).
1305     if (Previous.isSingleTagDecl())
1306       Previous.clear();
1307   }
1308 
1309   SemaRef.CheckFunctionDeclaration(/*Scope*/ 0, Function, Previous,
1310                                    isExplicitSpecialization);
1311 
1312   NamedDecl *PrincipalDecl = (TemplateParams
1313                               ? cast<NamedDecl>(FunctionTemplate)
1314                               : Function);
1315 
1316   // If the original function was part of a friend declaration,
1317   // inherit its namespace state and add it to the owner.
1318   if (isFriend) {
1319     NamedDecl *PrevDecl;
1320     if (TemplateParams)
1321       PrevDecl = FunctionTemplate->getPreviousDecl();
1322     else
1323       PrevDecl = Function->getPreviousDecl();
1324 
1325     PrincipalDecl->setObjectOfFriendDecl(PrevDecl != 0);
1326     DC->makeDeclVisibleInContext(PrincipalDecl);
1327 
1328     bool queuedInstantiation = false;
1329 
1330     // C++98 [temp.friend]p5: When a function is defined in a friend function
1331     //   declaration in a class template, the function is defined at each
1332     //   instantiation of the class template. The function is defined even if it
1333     //   is never used.
1334     // C++11 [temp.friend]p4: When a function is defined in a friend function
1335     //   declaration in a class template, the function is instantiated when the
1336     //   function is odr-used.
1337     //
1338     // If -Wc++98-compat is enabled, we go through the motions of checking for a
1339     // redefinition, but don't instantiate the function.
1340     if ((!SemaRef.getLangOpts().CPlusPlus11 ||
1341          SemaRef.Diags.getDiagnosticLevel(
1342              diag::warn_cxx98_compat_friend_redefinition,
1343              Function->getLocation())
1344            != DiagnosticsEngine::Ignored) &&
1345         D->isThisDeclarationADefinition()) {
1346       // Check for a function body.
1347       const FunctionDecl *Definition = 0;
1348       if (Function->isDefined(Definition) &&
1349           Definition->getTemplateSpecializationKind() == TSK_Undeclared) {
1350         SemaRef.Diag(Function->getLocation(),
1351                      SemaRef.getLangOpts().CPlusPlus11 ?
1352                        diag::warn_cxx98_compat_friend_redefinition :
1353                        diag::err_redefinition) << Function->getDeclName();
1354         SemaRef.Diag(Definition->getLocation(), diag::note_previous_definition);
1355         if (!SemaRef.getLangOpts().CPlusPlus11)
1356           Function->setInvalidDecl();
1357       }
1358       // Check for redefinitions due to other instantiations of this or
1359       // a similar friend function.
1360       else for (FunctionDecl::redecl_iterator R = Function->redecls_begin(),
1361                                            REnd = Function->redecls_end();
1362                 R != REnd; ++R) {
1363         if (*R == Function)
1364           continue;
1365         switch (R->getFriendObjectKind()) {
1366         case Decl::FOK_None:
1367           if (!SemaRef.getLangOpts().CPlusPlus11 &&
1368               !queuedInstantiation && R->isUsed(false)) {
1369             if (MemberSpecializationInfo *MSInfo
1370                 = Function->getMemberSpecializationInfo()) {
1371               if (MSInfo->getPointOfInstantiation().isInvalid()) {
1372                 SourceLocation Loc = R->getLocation(); // FIXME
1373                 MSInfo->setPointOfInstantiation(Loc);
1374                 SemaRef.PendingLocalImplicitInstantiations.push_back(
1375                                                  std::make_pair(Function, Loc));
1376                 queuedInstantiation = true;
1377               }
1378             }
1379           }
1380           break;
1381         default:
1382           if (const FunctionDecl *RPattern
1383               = R->getTemplateInstantiationPattern())
1384             if (RPattern->isDefined(RPattern)) {
1385               SemaRef.Diag(Function->getLocation(),
1386                            SemaRef.getLangOpts().CPlusPlus11 ?
1387                              diag::warn_cxx98_compat_friend_redefinition :
1388                              diag::err_redefinition)
1389                 << Function->getDeclName();
1390               SemaRef.Diag(R->getLocation(), diag::note_previous_definition);
1391               if (!SemaRef.getLangOpts().CPlusPlus11)
1392                 Function->setInvalidDecl();
1393               break;
1394             }
1395         }
1396       }
1397     }
1398   }
1399 
1400   if (Function->isOverloadedOperator() && !DC->isRecord() &&
1401       PrincipalDecl->isInIdentifierNamespace(Decl::IDNS_Ordinary))
1402     PrincipalDecl->setNonMemberOperator();
1403 
1404   assert(!D->isDefaulted() && "only methods should be defaulted");
1405   return Function;
1406 }
1407 
1408 Decl *
VisitCXXMethodDecl(CXXMethodDecl * D,TemplateParameterList * TemplateParams,bool IsClassScopeSpecialization)1409 TemplateDeclInstantiator::VisitCXXMethodDecl(CXXMethodDecl *D,
1410                                       TemplateParameterList *TemplateParams,
1411                                       bool IsClassScopeSpecialization) {
1412   FunctionTemplateDecl *FunctionTemplate = D->getDescribedFunctionTemplate();
1413   if (FunctionTemplate && !TemplateParams) {
1414     // We are creating a function template specialization from a function
1415     // template. Check whether there is already a function template
1416     // specialization for this particular set of template arguments.
1417     std::pair<const TemplateArgument *, unsigned> Innermost
1418       = TemplateArgs.getInnermost();
1419 
1420     void *InsertPos = 0;
1421     FunctionDecl *SpecFunc
1422       = FunctionTemplate->findSpecialization(Innermost.first, Innermost.second,
1423                                              InsertPos);
1424 
1425     // If we already have a function template specialization, return it.
1426     if (SpecFunc)
1427       return SpecFunc;
1428   }
1429 
1430   bool isFriend;
1431   if (FunctionTemplate)
1432     isFriend = (FunctionTemplate->getFriendObjectKind() != Decl::FOK_None);
1433   else
1434     isFriend = (D->getFriendObjectKind() != Decl::FOK_None);
1435 
1436   bool MergeWithParentScope = (TemplateParams != 0) ||
1437     !(isa<Decl>(Owner) &&
1438       cast<Decl>(Owner)->isDefinedOutsideFunctionOrMethod());
1439   LocalInstantiationScope Scope(SemaRef, MergeWithParentScope);
1440 
1441   // Instantiate enclosing template arguments for friends.
1442   SmallVector<TemplateParameterList *, 4> TempParamLists;
1443   unsigned NumTempParamLists = 0;
1444   if (isFriend && (NumTempParamLists = D->getNumTemplateParameterLists())) {
1445     TempParamLists.set_size(NumTempParamLists);
1446     for (unsigned I = 0; I != NumTempParamLists; ++I) {
1447       TemplateParameterList *TempParams = D->getTemplateParameterList(I);
1448       TemplateParameterList *InstParams = SubstTemplateParams(TempParams);
1449       if (!InstParams)
1450         return NULL;
1451       TempParamLists[I] = InstParams;
1452     }
1453   }
1454 
1455   SmallVector<ParmVarDecl *, 4> Params;
1456   TypeSourceInfo *TInfo = SubstFunctionType(D, Params);
1457   if (!TInfo)
1458     return 0;
1459   QualType T = adjustFunctionTypeForInstantiation(SemaRef.Context, D, TInfo);
1460 
1461   // \brief If the type of this function, after ignoring parentheses,
1462   // is not *directly* a function type, then we're instantiating a function
1463   // that was declared via a typedef, e.g.,
1464   //
1465   //   typedef int functype(int, int);
1466   //   functype func;
1467   //
1468   // In this case, we'll just go instantiate the ParmVarDecls that we
1469   // synthesized in the method declaration.
1470   if (!isa<FunctionProtoType>(T.IgnoreParens())) {
1471     assert(!Params.size() && "Instantiating type could not yield parameters");
1472     SmallVector<QualType, 4> ParamTypes;
1473     if (SemaRef.SubstParmTypes(D->getLocation(), D->param_begin(),
1474                                D->getNumParams(), TemplateArgs, ParamTypes,
1475                                &Params))
1476       return 0;
1477   }
1478 
1479   NestedNameSpecifierLoc QualifierLoc = D->getQualifierLoc();
1480   if (QualifierLoc) {
1481     QualifierLoc = SemaRef.SubstNestedNameSpecifierLoc(QualifierLoc,
1482                                                  TemplateArgs);
1483     if (!QualifierLoc)
1484       return 0;
1485   }
1486 
1487   DeclContext *DC = Owner;
1488   if (isFriend) {
1489     if (QualifierLoc) {
1490       CXXScopeSpec SS;
1491       SS.Adopt(QualifierLoc);
1492       DC = SemaRef.computeDeclContext(SS);
1493 
1494       if (DC && SemaRef.RequireCompleteDeclContext(SS, DC))
1495         return 0;
1496     } else {
1497       DC = SemaRef.FindInstantiatedContext(D->getLocation(),
1498                                            D->getDeclContext(),
1499                                            TemplateArgs);
1500     }
1501     if (!DC) return 0;
1502   }
1503 
1504   // Build the instantiated method declaration.
1505   CXXRecordDecl *Record = cast<CXXRecordDecl>(DC);
1506   CXXMethodDecl *Method = 0;
1507 
1508   SourceLocation StartLoc = D->getInnerLocStart();
1509   DeclarationNameInfo NameInfo
1510     = SemaRef.SubstDeclarationNameInfo(D->getNameInfo(), TemplateArgs);
1511   if (CXXConstructorDecl *Constructor = dyn_cast<CXXConstructorDecl>(D)) {
1512     Method = CXXConstructorDecl::Create(SemaRef.Context, Record,
1513                                         StartLoc, NameInfo, T, TInfo,
1514                                         Constructor->isExplicit(),
1515                                         Constructor->isInlineSpecified(),
1516                                         false, Constructor->isConstexpr());
1517   } else if (CXXDestructorDecl *Destructor = dyn_cast<CXXDestructorDecl>(D)) {
1518     Method = CXXDestructorDecl::Create(SemaRef.Context, Record,
1519                                        StartLoc, NameInfo, T, TInfo,
1520                                        Destructor->isInlineSpecified(),
1521                                        false);
1522   } else if (CXXConversionDecl *Conversion = dyn_cast<CXXConversionDecl>(D)) {
1523     Method = CXXConversionDecl::Create(SemaRef.Context, Record,
1524                                        StartLoc, NameInfo, T, TInfo,
1525                                        Conversion->isInlineSpecified(),
1526                                        Conversion->isExplicit(),
1527                                        Conversion->isConstexpr(),
1528                                        Conversion->getLocEnd());
1529   } else {
1530     Method = CXXMethodDecl::Create(SemaRef.Context, Record,
1531                                    StartLoc, NameInfo, T, TInfo,
1532                                    D->isStatic(),
1533                                    D->getStorageClassAsWritten(),
1534                                    D->isInlineSpecified(),
1535                                    D->isConstexpr(), D->getLocEnd());
1536   }
1537 
1538   if (D->isInlined())
1539     Method->setImplicitlyInline();
1540 
1541   if (QualifierLoc)
1542     Method->setQualifierInfo(QualifierLoc);
1543 
1544   if (TemplateParams) {
1545     // Our resulting instantiation is actually a function template, since we
1546     // are substituting only the outer template parameters. For example, given
1547     //
1548     //   template<typename T>
1549     //   struct X {
1550     //     template<typename U> void f(T, U);
1551     //   };
1552     //
1553     //   X<int> x;
1554     //
1555     // We are instantiating the member template "f" within X<int>, which means
1556     // substituting int for T, but leaving "f" as a member function template.
1557     // Build the function template itself.
1558     FunctionTemplate = FunctionTemplateDecl::Create(SemaRef.Context, Record,
1559                                                     Method->getLocation(),
1560                                                     Method->getDeclName(),
1561                                                     TemplateParams, Method);
1562     if (isFriend) {
1563       FunctionTemplate->setLexicalDeclContext(Owner);
1564       FunctionTemplate->setObjectOfFriendDecl(true);
1565     } else if (D->isOutOfLine())
1566       FunctionTemplate->setLexicalDeclContext(D->getLexicalDeclContext());
1567     Method->setDescribedFunctionTemplate(FunctionTemplate);
1568   } else if (FunctionTemplate) {
1569     // Record this function template specialization.
1570     std::pair<const TemplateArgument *, unsigned> Innermost
1571       = TemplateArgs.getInnermost();
1572     Method->setFunctionTemplateSpecialization(FunctionTemplate,
1573                          TemplateArgumentList::CreateCopy(SemaRef.Context,
1574                                                           Innermost.first,
1575                                                           Innermost.second),
1576                                               /*InsertPos=*/0);
1577   } else if (!isFriend) {
1578     // Record that this is an instantiation of a member function.
1579     Method->setInstantiationOfMemberFunction(D, TSK_ImplicitInstantiation);
1580   }
1581 
1582   // If we are instantiating a member function defined
1583   // out-of-line, the instantiation will have the same lexical
1584   // context (which will be a namespace scope) as the template.
1585   if (isFriend) {
1586     if (NumTempParamLists)
1587       Method->setTemplateParameterListsInfo(SemaRef.Context,
1588                                             NumTempParamLists,
1589                                             TempParamLists.data());
1590 
1591     Method->setLexicalDeclContext(Owner);
1592     Method->setObjectOfFriendDecl(true);
1593   } else if (D->isOutOfLine())
1594     Method->setLexicalDeclContext(D->getLexicalDeclContext());
1595 
1596   // Attach the parameters
1597   for (unsigned P = 0; P < Params.size(); ++P)
1598     Params[P]->setOwningFunction(Method);
1599   Method->setParams(Params);
1600 
1601   if (InitMethodInstantiation(Method, D))
1602     Method->setInvalidDecl();
1603 
1604   LookupResult Previous(SemaRef, NameInfo, Sema::LookupOrdinaryName,
1605                         Sema::ForRedeclaration);
1606 
1607   if (!FunctionTemplate || TemplateParams || isFriend) {
1608     SemaRef.LookupQualifiedName(Previous, Record);
1609 
1610     // In C++, the previous declaration we find might be a tag type
1611     // (class or enum). In this case, the new declaration will hide the
1612     // tag type. Note that this does does not apply if we're declaring a
1613     // typedef (C++ [dcl.typedef]p4).
1614     if (Previous.isSingleTagDecl())
1615       Previous.clear();
1616   }
1617 
1618   if (!IsClassScopeSpecialization)
1619     SemaRef.CheckFunctionDeclaration(0, Method, Previous, false);
1620 
1621   if (D->isPure())
1622     SemaRef.CheckPureMethod(Method, SourceRange());
1623 
1624   // Propagate access.  For a non-friend declaration, the access is
1625   // whatever we're propagating from.  For a friend, it should be the
1626   // previous declaration we just found.
1627   if (isFriend && Method->getPreviousDecl())
1628     Method->setAccess(Method->getPreviousDecl()->getAccess());
1629   else
1630     Method->setAccess(D->getAccess());
1631   if (FunctionTemplate)
1632     FunctionTemplate->setAccess(Method->getAccess());
1633 
1634   SemaRef.CheckOverrideControl(Method);
1635 
1636   // If a function is defined as defaulted or deleted, mark it as such now.
1637   if (D->isExplicitlyDefaulted())
1638     SemaRef.SetDeclDefaulted(Method, Method->getLocation());
1639   if (D->isDeletedAsWritten())
1640     SemaRef.SetDeclDeleted(Method, Method->getLocation());
1641 
1642   // If there's a function template, let our caller handle it.
1643   if (FunctionTemplate) {
1644     // do nothing
1645 
1646   // Don't hide a (potentially) valid declaration with an invalid one.
1647   } else if (Method->isInvalidDecl() && !Previous.empty()) {
1648     // do nothing
1649 
1650   // Otherwise, check access to friends and make them visible.
1651   } else if (isFriend) {
1652     // We only need to re-check access for methods which we didn't
1653     // manage to match during parsing.
1654     if (!D->getPreviousDecl())
1655       SemaRef.CheckFriendAccess(Method);
1656 
1657     Record->makeDeclVisibleInContext(Method);
1658 
1659   // Otherwise, add the declaration.  We don't need to do this for
1660   // class-scope specializations because we'll have matched them with
1661   // the appropriate template.
1662   } else if (!IsClassScopeSpecialization) {
1663     Owner->addDecl(Method);
1664   }
1665 
1666   return Method;
1667 }
1668 
VisitCXXConstructorDecl(CXXConstructorDecl * D)1669 Decl *TemplateDeclInstantiator::VisitCXXConstructorDecl(CXXConstructorDecl *D) {
1670   return VisitCXXMethodDecl(D);
1671 }
1672 
VisitCXXDestructorDecl(CXXDestructorDecl * D)1673 Decl *TemplateDeclInstantiator::VisitCXXDestructorDecl(CXXDestructorDecl *D) {
1674   return VisitCXXMethodDecl(D);
1675 }
1676 
VisitCXXConversionDecl(CXXConversionDecl * D)1677 Decl *TemplateDeclInstantiator::VisitCXXConversionDecl(CXXConversionDecl *D) {
1678   return VisitCXXMethodDecl(D);
1679 }
1680 
VisitParmVarDecl(ParmVarDecl * D)1681 ParmVarDecl *TemplateDeclInstantiator::VisitParmVarDecl(ParmVarDecl *D) {
1682   return SemaRef.SubstParmVarDecl(D, TemplateArgs, /*indexAdjustment*/ 0, None,
1683                                   /*ExpectParameterPack=*/ false);
1684 }
1685 
VisitTemplateTypeParmDecl(TemplateTypeParmDecl * D)1686 Decl *TemplateDeclInstantiator::VisitTemplateTypeParmDecl(
1687                                                     TemplateTypeParmDecl *D) {
1688   // TODO: don't always clone when decls are refcounted.
1689   assert(D->getTypeForDecl()->isTemplateTypeParmType());
1690 
1691   TemplateTypeParmDecl *Inst =
1692     TemplateTypeParmDecl::Create(SemaRef.Context, Owner,
1693                                  D->getLocStart(), D->getLocation(),
1694                                  D->getDepth() - TemplateArgs.getNumLevels(),
1695                                  D->getIndex(), D->getIdentifier(),
1696                                  D->wasDeclaredWithTypename(),
1697                                  D->isParameterPack());
1698   Inst->setAccess(AS_public);
1699 
1700   if (D->hasDefaultArgument())
1701     Inst->setDefaultArgument(D->getDefaultArgumentInfo(), false);
1702 
1703   // Introduce this template parameter's instantiation into the instantiation
1704   // scope.
1705   SemaRef.CurrentInstantiationScope->InstantiatedLocal(D, Inst);
1706 
1707   return Inst;
1708 }
1709 
VisitNonTypeTemplateParmDecl(NonTypeTemplateParmDecl * D)1710 Decl *TemplateDeclInstantiator::VisitNonTypeTemplateParmDecl(
1711                                                  NonTypeTemplateParmDecl *D) {
1712   // Substitute into the type of the non-type template parameter.
1713   TypeLoc TL = D->getTypeSourceInfo()->getTypeLoc();
1714   SmallVector<TypeSourceInfo *, 4> ExpandedParameterPackTypesAsWritten;
1715   SmallVector<QualType, 4> ExpandedParameterPackTypes;
1716   bool IsExpandedParameterPack = false;
1717   TypeSourceInfo *DI;
1718   QualType T;
1719   bool Invalid = false;
1720 
1721   if (D->isExpandedParameterPack()) {
1722     // The non-type template parameter pack is an already-expanded pack
1723     // expansion of types. Substitute into each of the expanded types.
1724     ExpandedParameterPackTypes.reserve(D->getNumExpansionTypes());
1725     ExpandedParameterPackTypesAsWritten.reserve(D->getNumExpansionTypes());
1726     for (unsigned I = 0, N = D->getNumExpansionTypes(); I != N; ++I) {
1727       TypeSourceInfo *NewDI =SemaRef.SubstType(D->getExpansionTypeSourceInfo(I),
1728                                                TemplateArgs,
1729                                                D->getLocation(),
1730                                                D->getDeclName());
1731       if (!NewDI)
1732         return 0;
1733 
1734       ExpandedParameterPackTypesAsWritten.push_back(NewDI);
1735       QualType NewT =SemaRef.CheckNonTypeTemplateParameterType(NewDI->getType(),
1736                                                               D->getLocation());
1737       if (NewT.isNull())
1738         return 0;
1739       ExpandedParameterPackTypes.push_back(NewT);
1740     }
1741 
1742     IsExpandedParameterPack = true;
1743     DI = D->getTypeSourceInfo();
1744     T = DI->getType();
1745   } else if (D->isPackExpansion()) {
1746     // The non-type template parameter pack's type is a pack expansion of types.
1747     // Determine whether we need to expand this parameter pack into separate
1748     // types.
1749     PackExpansionTypeLoc Expansion = TL.castAs<PackExpansionTypeLoc>();
1750     TypeLoc Pattern = Expansion.getPatternLoc();
1751     SmallVector<UnexpandedParameterPack, 2> Unexpanded;
1752     SemaRef.collectUnexpandedParameterPacks(Pattern, Unexpanded);
1753 
1754     // Determine whether the set of unexpanded parameter packs can and should
1755     // be expanded.
1756     bool Expand = true;
1757     bool RetainExpansion = false;
1758     Optional<unsigned> OrigNumExpansions
1759       = Expansion.getTypePtr()->getNumExpansions();
1760     Optional<unsigned> NumExpansions = OrigNumExpansions;
1761     if (SemaRef.CheckParameterPacksForExpansion(Expansion.getEllipsisLoc(),
1762                                                 Pattern.getSourceRange(),
1763                                                 Unexpanded,
1764                                                 TemplateArgs,
1765                                                 Expand, RetainExpansion,
1766                                                 NumExpansions))
1767       return 0;
1768 
1769     if (Expand) {
1770       for (unsigned I = 0; I != *NumExpansions; ++I) {
1771         Sema::ArgumentPackSubstitutionIndexRAII SubstIndex(SemaRef, I);
1772         TypeSourceInfo *NewDI = SemaRef.SubstType(Pattern, TemplateArgs,
1773                                                   D->getLocation(),
1774                                                   D->getDeclName());
1775         if (!NewDI)
1776           return 0;
1777 
1778         ExpandedParameterPackTypesAsWritten.push_back(NewDI);
1779         QualType NewT = SemaRef.CheckNonTypeTemplateParameterType(
1780                                                               NewDI->getType(),
1781                                                               D->getLocation());
1782         if (NewT.isNull())
1783           return 0;
1784         ExpandedParameterPackTypes.push_back(NewT);
1785       }
1786 
1787       // Note that we have an expanded parameter pack. The "type" of this
1788       // expanded parameter pack is the original expansion type, but callers
1789       // will end up using the expanded parameter pack types for type-checking.
1790       IsExpandedParameterPack = true;
1791       DI = D->getTypeSourceInfo();
1792       T = DI->getType();
1793     } else {
1794       // We cannot fully expand the pack expansion now, so substitute into the
1795       // pattern and create a new pack expansion type.
1796       Sema::ArgumentPackSubstitutionIndexRAII SubstIndex(SemaRef, -1);
1797       TypeSourceInfo *NewPattern = SemaRef.SubstType(Pattern, TemplateArgs,
1798                                                      D->getLocation(),
1799                                                      D->getDeclName());
1800       if (!NewPattern)
1801         return 0;
1802 
1803       DI = SemaRef.CheckPackExpansion(NewPattern, Expansion.getEllipsisLoc(),
1804                                       NumExpansions);
1805       if (!DI)
1806         return 0;
1807 
1808       T = DI->getType();
1809     }
1810   } else {
1811     // Simple case: substitution into a parameter that is not a parameter pack.
1812     DI = SemaRef.SubstType(D->getTypeSourceInfo(), TemplateArgs,
1813                            D->getLocation(), D->getDeclName());
1814     if (!DI)
1815       return 0;
1816 
1817     // Check that this type is acceptable for a non-type template parameter.
1818     T = SemaRef.CheckNonTypeTemplateParameterType(DI->getType(),
1819                                                   D->getLocation());
1820     if (T.isNull()) {
1821       T = SemaRef.Context.IntTy;
1822       Invalid = true;
1823     }
1824   }
1825 
1826   NonTypeTemplateParmDecl *Param;
1827   if (IsExpandedParameterPack)
1828     Param = NonTypeTemplateParmDecl::Create(SemaRef.Context, Owner,
1829                                             D->getInnerLocStart(),
1830                                             D->getLocation(),
1831                                     D->getDepth() - TemplateArgs.getNumLevels(),
1832                                             D->getPosition(),
1833                                             D->getIdentifier(), T,
1834                                             DI,
1835                                             ExpandedParameterPackTypes.data(),
1836                                             ExpandedParameterPackTypes.size(),
1837                                     ExpandedParameterPackTypesAsWritten.data());
1838   else
1839     Param = NonTypeTemplateParmDecl::Create(SemaRef.Context, Owner,
1840                                             D->getInnerLocStart(),
1841                                             D->getLocation(),
1842                                     D->getDepth() - TemplateArgs.getNumLevels(),
1843                                             D->getPosition(),
1844                                             D->getIdentifier(), T,
1845                                             D->isParameterPack(), DI);
1846 
1847   Param->setAccess(AS_public);
1848   if (Invalid)
1849     Param->setInvalidDecl();
1850 
1851   Param->setDefaultArgument(D->getDefaultArgument(), false);
1852 
1853   // Introduce this template parameter's instantiation into the instantiation
1854   // scope.
1855   SemaRef.CurrentInstantiationScope->InstantiatedLocal(D, Param);
1856   return Param;
1857 }
1858 
collectUnexpandedParameterPacks(Sema & S,TemplateParameterList * Params,SmallVectorImpl<UnexpandedParameterPack> & Unexpanded)1859 static void collectUnexpandedParameterPacks(
1860     Sema &S,
1861     TemplateParameterList *Params,
1862     SmallVectorImpl<UnexpandedParameterPack> &Unexpanded) {
1863   for (TemplateParameterList::const_iterator I = Params->begin(),
1864                                              E = Params->end(); I != E; ++I) {
1865     if ((*I)->isTemplateParameterPack())
1866       continue;
1867     if (NonTypeTemplateParmDecl *NTTP = dyn_cast<NonTypeTemplateParmDecl>(*I))
1868       S.collectUnexpandedParameterPacks(NTTP->getTypeSourceInfo()->getTypeLoc(),
1869                                         Unexpanded);
1870     if (TemplateTemplateParmDecl *TTP = dyn_cast<TemplateTemplateParmDecl>(*I))
1871       collectUnexpandedParameterPacks(S, TTP->getTemplateParameters(),
1872                                       Unexpanded);
1873   }
1874 }
1875 
1876 Decl *
VisitTemplateTemplateParmDecl(TemplateTemplateParmDecl * D)1877 TemplateDeclInstantiator::VisitTemplateTemplateParmDecl(
1878                                                   TemplateTemplateParmDecl *D) {
1879   // Instantiate the template parameter list of the template template parameter.
1880   TemplateParameterList *TempParams = D->getTemplateParameters();
1881   TemplateParameterList *InstParams;
1882   SmallVector<TemplateParameterList*, 8> ExpandedParams;
1883 
1884   bool IsExpandedParameterPack = false;
1885 
1886   if (D->isExpandedParameterPack()) {
1887     // The template template parameter pack is an already-expanded pack
1888     // expansion of template parameters. Substitute into each of the expanded
1889     // parameters.
1890     ExpandedParams.reserve(D->getNumExpansionTemplateParameters());
1891     for (unsigned I = 0, N = D->getNumExpansionTemplateParameters();
1892          I != N; ++I) {
1893       LocalInstantiationScope Scope(SemaRef);
1894       TemplateParameterList *Expansion =
1895         SubstTemplateParams(D->getExpansionTemplateParameters(I));
1896       if (!Expansion)
1897         return 0;
1898       ExpandedParams.push_back(Expansion);
1899     }
1900 
1901     IsExpandedParameterPack = true;
1902     InstParams = TempParams;
1903   } else if (D->isPackExpansion()) {
1904     // The template template parameter pack expands to a pack of template
1905     // template parameters. Determine whether we need to expand this parameter
1906     // pack into separate parameters.
1907     SmallVector<UnexpandedParameterPack, 2> Unexpanded;
1908     collectUnexpandedParameterPacks(SemaRef, D->getTemplateParameters(),
1909                                     Unexpanded);
1910 
1911     // Determine whether the set of unexpanded parameter packs can and should
1912     // be expanded.
1913     bool Expand = true;
1914     bool RetainExpansion = false;
1915     Optional<unsigned> NumExpansions;
1916     if (SemaRef.CheckParameterPacksForExpansion(D->getLocation(),
1917                                                 TempParams->getSourceRange(),
1918                                                 Unexpanded,
1919                                                 TemplateArgs,
1920                                                 Expand, RetainExpansion,
1921                                                 NumExpansions))
1922       return 0;
1923 
1924     if (Expand) {
1925       for (unsigned I = 0; I != *NumExpansions; ++I) {
1926         Sema::ArgumentPackSubstitutionIndexRAII SubstIndex(SemaRef, I);
1927         LocalInstantiationScope Scope(SemaRef);
1928         TemplateParameterList *Expansion = SubstTemplateParams(TempParams);
1929         if (!Expansion)
1930           return 0;
1931         ExpandedParams.push_back(Expansion);
1932       }
1933 
1934       // Note that we have an expanded parameter pack. The "type" of this
1935       // expanded parameter pack is the original expansion type, but callers
1936       // will end up using the expanded parameter pack types for type-checking.
1937       IsExpandedParameterPack = true;
1938       InstParams = TempParams;
1939     } else {
1940       // We cannot fully expand the pack expansion now, so just substitute
1941       // into the pattern.
1942       Sema::ArgumentPackSubstitutionIndexRAII SubstIndex(SemaRef, -1);
1943 
1944       LocalInstantiationScope Scope(SemaRef);
1945       InstParams = SubstTemplateParams(TempParams);
1946       if (!InstParams)
1947         return 0;
1948     }
1949   } else {
1950     // Perform the actual substitution of template parameters within a new,
1951     // local instantiation scope.
1952     LocalInstantiationScope Scope(SemaRef);
1953     InstParams = SubstTemplateParams(TempParams);
1954     if (!InstParams)
1955       return 0;
1956   }
1957 
1958   // Build the template template parameter.
1959   TemplateTemplateParmDecl *Param;
1960   if (IsExpandedParameterPack)
1961     Param = TemplateTemplateParmDecl::Create(SemaRef.Context, Owner,
1962                                              D->getLocation(),
1963                                    D->getDepth() - TemplateArgs.getNumLevels(),
1964                                              D->getPosition(),
1965                                              D->getIdentifier(), InstParams,
1966                                              ExpandedParams);
1967   else
1968     Param = TemplateTemplateParmDecl::Create(SemaRef.Context, Owner,
1969                                              D->getLocation(),
1970                                    D->getDepth() - TemplateArgs.getNumLevels(),
1971                                              D->getPosition(),
1972                                              D->isParameterPack(),
1973                                              D->getIdentifier(), InstParams);
1974   Param->setDefaultArgument(D->getDefaultArgument(), false);
1975   Param->setAccess(AS_public);
1976 
1977   // Introduce this template parameter's instantiation into the instantiation
1978   // scope.
1979   SemaRef.CurrentInstantiationScope->InstantiatedLocal(D, Param);
1980 
1981   return Param;
1982 }
1983 
VisitUsingDirectiveDecl(UsingDirectiveDecl * D)1984 Decl *TemplateDeclInstantiator::VisitUsingDirectiveDecl(UsingDirectiveDecl *D) {
1985   // Using directives are never dependent (and never contain any types or
1986   // expressions), so they require no explicit instantiation work.
1987 
1988   UsingDirectiveDecl *Inst
1989     = UsingDirectiveDecl::Create(SemaRef.Context, Owner, D->getLocation(),
1990                                  D->getNamespaceKeyLocation(),
1991                                  D->getQualifierLoc(),
1992                                  D->getIdentLocation(),
1993                                  D->getNominatedNamespace(),
1994                                  D->getCommonAncestor());
1995 
1996   // Add the using directive to its declaration context
1997   // only if this is not a function or method.
1998   if (!Owner->isFunctionOrMethod())
1999     Owner->addDecl(Inst);
2000 
2001   return Inst;
2002 }
2003 
VisitUsingDecl(UsingDecl * D)2004 Decl *TemplateDeclInstantiator::VisitUsingDecl(UsingDecl *D) {
2005 
2006   // The nested name specifier may be dependent, for example
2007   //     template <typename T> struct t {
2008   //       struct s1 { T f1(); };
2009   //       struct s2 : s1 { using s1::f1; };
2010   //     };
2011   //     template struct t<int>;
2012   // Here, in using s1::f1, s1 refers to t<T>::s1;
2013   // we need to substitute for t<int>::s1.
2014   NestedNameSpecifierLoc QualifierLoc
2015     = SemaRef.SubstNestedNameSpecifierLoc(D->getQualifierLoc(),
2016                                           TemplateArgs);
2017   if (!QualifierLoc)
2018     return 0;
2019 
2020   // The name info is non-dependent, so no transformation
2021   // is required.
2022   DeclarationNameInfo NameInfo = D->getNameInfo();
2023 
2024   // We only need to do redeclaration lookups if we're in a class
2025   // scope (in fact, it's not really even possible in non-class
2026   // scopes).
2027   bool CheckRedeclaration = Owner->isRecord();
2028 
2029   LookupResult Prev(SemaRef, NameInfo, Sema::LookupUsingDeclName,
2030                     Sema::ForRedeclaration);
2031 
2032   UsingDecl *NewUD = UsingDecl::Create(SemaRef.Context, Owner,
2033                                        D->getUsingLocation(),
2034                                        QualifierLoc,
2035                                        NameInfo,
2036                                        D->isTypeName());
2037 
2038   CXXScopeSpec SS;
2039   SS.Adopt(QualifierLoc);
2040   if (CheckRedeclaration) {
2041     Prev.setHideTags(false);
2042     SemaRef.LookupQualifiedName(Prev, Owner);
2043 
2044     // Check for invalid redeclarations.
2045     if (SemaRef.CheckUsingDeclRedeclaration(D->getUsingLocation(),
2046                                             D->isTypeName(), SS,
2047                                             D->getLocation(), Prev))
2048       NewUD->setInvalidDecl();
2049 
2050   }
2051 
2052   if (!NewUD->isInvalidDecl() &&
2053       SemaRef.CheckUsingDeclQualifier(D->getUsingLocation(), SS,
2054                                       D->getLocation()))
2055     NewUD->setInvalidDecl();
2056 
2057   SemaRef.Context.setInstantiatedFromUsingDecl(NewUD, D);
2058   NewUD->setAccess(D->getAccess());
2059   Owner->addDecl(NewUD);
2060 
2061   // Don't process the shadow decls for an invalid decl.
2062   if (NewUD->isInvalidDecl())
2063     return NewUD;
2064 
2065   if (NameInfo.getName().getNameKind() == DeclarationName::CXXConstructorName) {
2066     if (SemaRef.CheckInheritingConstructorUsingDecl(NewUD))
2067       NewUD->setInvalidDecl();
2068     return NewUD;
2069   }
2070 
2071   bool isFunctionScope = Owner->isFunctionOrMethod();
2072 
2073   // Process the shadow decls.
2074   for (UsingDecl::shadow_iterator I = D->shadow_begin(), E = D->shadow_end();
2075          I != E; ++I) {
2076     UsingShadowDecl *Shadow = *I;
2077     NamedDecl *InstTarget =
2078       cast_or_null<NamedDecl>(SemaRef.FindInstantiatedDecl(
2079                                                           Shadow->getLocation(),
2080                                                         Shadow->getTargetDecl(),
2081                                                            TemplateArgs));
2082     if (!InstTarget)
2083       return 0;
2084 
2085     if (CheckRedeclaration &&
2086         SemaRef.CheckUsingShadowDecl(NewUD, InstTarget, Prev))
2087       continue;
2088 
2089     UsingShadowDecl *InstShadow
2090       = SemaRef.BuildUsingShadowDecl(/*Scope*/ 0, NewUD, InstTarget);
2091     SemaRef.Context.setInstantiatedFromUsingShadowDecl(InstShadow, Shadow);
2092 
2093     if (isFunctionScope)
2094       SemaRef.CurrentInstantiationScope->InstantiatedLocal(Shadow, InstShadow);
2095   }
2096 
2097   return NewUD;
2098 }
2099 
VisitUsingShadowDecl(UsingShadowDecl * D)2100 Decl *TemplateDeclInstantiator::VisitUsingShadowDecl(UsingShadowDecl *D) {
2101   // Ignore these;  we handle them in bulk when processing the UsingDecl.
2102   return 0;
2103 }
2104 
2105 Decl * TemplateDeclInstantiator
VisitUnresolvedUsingTypenameDecl(UnresolvedUsingTypenameDecl * D)2106     ::VisitUnresolvedUsingTypenameDecl(UnresolvedUsingTypenameDecl *D) {
2107   NestedNameSpecifierLoc QualifierLoc
2108     = SemaRef.SubstNestedNameSpecifierLoc(D->getQualifierLoc(),
2109                                           TemplateArgs);
2110   if (!QualifierLoc)
2111     return 0;
2112 
2113   CXXScopeSpec SS;
2114   SS.Adopt(QualifierLoc);
2115 
2116   // Since NameInfo refers to a typename, it cannot be a C++ special name.
2117   // Hence, no transformation is required for it.
2118   DeclarationNameInfo NameInfo(D->getDeclName(), D->getLocation());
2119   NamedDecl *UD =
2120     SemaRef.BuildUsingDeclaration(/*Scope*/ 0, D->getAccess(),
2121                                   D->getUsingLoc(), SS, NameInfo, 0,
2122                                   /*instantiation*/ true,
2123                                   /*typename*/ true, D->getTypenameLoc());
2124   if (UD)
2125     SemaRef.Context.setInstantiatedFromUsingDecl(cast<UsingDecl>(UD), D);
2126 
2127   return UD;
2128 }
2129 
2130 Decl * TemplateDeclInstantiator
VisitUnresolvedUsingValueDecl(UnresolvedUsingValueDecl * D)2131     ::VisitUnresolvedUsingValueDecl(UnresolvedUsingValueDecl *D) {
2132   NestedNameSpecifierLoc QualifierLoc
2133       = SemaRef.SubstNestedNameSpecifierLoc(D->getQualifierLoc(), TemplateArgs);
2134   if (!QualifierLoc)
2135     return 0;
2136 
2137   CXXScopeSpec SS;
2138   SS.Adopt(QualifierLoc);
2139 
2140   DeclarationNameInfo NameInfo
2141     = SemaRef.SubstDeclarationNameInfo(D->getNameInfo(), TemplateArgs);
2142 
2143   NamedDecl *UD =
2144     SemaRef.BuildUsingDeclaration(/*Scope*/ 0, D->getAccess(),
2145                                   D->getUsingLoc(), SS, NameInfo, 0,
2146                                   /*instantiation*/ true,
2147                                   /*typename*/ false, SourceLocation());
2148   if (UD)
2149     SemaRef.Context.setInstantiatedFromUsingDecl(cast<UsingDecl>(UD), D);
2150 
2151   return UD;
2152 }
2153 
2154 
VisitClassScopeFunctionSpecializationDecl(ClassScopeFunctionSpecializationDecl * Decl)2155 Decl *TemplateDeclInstantiator::VisitClassScopeFunctionSpecializationDecl(
2156                                      ClassScopeFunctionSpecializationDecl *Decl) {
2157   CXXMethodDecl *OldFD = Decl->getSpecialization();
2158   CXXMethodDecl *NewFD = cast<CXXMethodDecl>(VisitCXXMethodDecl(OldFD,
2159                                                                 0, true));
2160 
2161   LookupResult Previous(SemaRef, NewFD->getNameInfo(), Sema::LookupOrdinaryName,
2162                         Sema::ForRedeclaration);
2163 
2164   TemplateArgumentListInfo TemplateArgs;
2165   TemplateArgumentListInfo* TemplateArgsPtr = 0;
2166   if (Decl->hasExplicitTemplateArgs()) {
2167     TemplateArgs = Decl->templateArgs();
2168     TemplateArgsPtr = &TemplateArgs;
2169   }
2170 
2171   SemaRef.LookupQualifiedName(Previous, SemaRef.CurContext);
2172   if (SemaRef.CheckFunctionTemplateSpecialization(NewFD, TemplateArgsPtr,
2173                                                   Previous)) {
2174     NewFD->setInvalidDecl();
2175     return NewFD;
2176   }
2177 
2178   // Associate the specialization with the pattern.
2179   FunctionDecl *Specialization = cast<FunctionDecl>(Previous.getFoundDecl());
2180   assert(Specialization && "Class scope Specialization is null");
2181   SemaRef.Context.setClassScopeSpecializationPattern(Specialization, OldFD);
2182 
2183   return NewFD;
2184 }
2185 
SubstDecl(Decl * D,DeclContext * Owner,const MultiLevelTemplateArgumentList & TemplateArgs)2186 Decl *Sema::SubstDecl(Decl *D, DeclContext *Owner,
2187                       const MultiLevelTemplateArgumentList &TemplateArgs) {
2188   TemplateDeclInstantiator Instantiator(*this, Owner, TemplateArgs);
2189   if (D->isInvalidDecl())
2190     return 0;
2191 
2192   return Instantiator.Visit(D);
2193 }
2194 
2195 /// \brief Instantiates a nested template parameter list in the current
2196 /// instantiation context.
2197 ///
2198 /// \param L The parameter list to instantiate
2199 ///
2200 /// \returns NULL if there was an error
2201 TemplateParameterList *
SubstTemplateParams(TemplateParameterList * L)2202 TemplateDeclInstantiator::SubstTemplateParams(TemplateParameterList *L) {
2203   // Get errors for all the parameters before bailing out.
2204   bool Invalid = false;
2205 
2206   unsigned N = L->size();
2207   typedef SmallVector<NamedDecl *, 8> ParamVector;
2208   ParamVector Params;
2209   Params.reserve(N);
2210   for (TemplateParameterList::iterator PI = L->begin(), PE = L->end();
2211        PI != PE; ++PI) {
2212     NamedDecl *D = cast_or_null<NamedDecl>(Visit(*PI));
2213     Params.push_back(D);
2214     Invalid = Invalid || !D || D->isInvalidDecl();
2215   }
2216 
2217   // Clean up if we had an error.
2218   if (Invalid)
2219     return NULL;
2220 
2221   TemplateParameterList *InstL
2222     = TemplateParameterList::Create(SemaRef.Context, L->getTemplateLoc(),
2223                                     L->getLAngleLoc(), &Params.front(), N,
2224                                     L->getRAngleLoc());
2225   return InstL;
2226 }
2227 
2228 /// \brief Instantiate the declaration of a class template partial
2229 /// specialization.
2230 ///
2231 /// \param ClassTemplate the (instantiated) class template that is partially
2232 // specialized by the instantiation of \p PartialSpec.
2233 ///
2234 /// \param PartialSpec the (uninstantiated) class template partial
2235 /// specialization that we are instantiating.
2236 ///
2237 /// \returns The instantiated partial specialization, if successful; otherwise,
2238 /// NULL to indicate an error.
2239 ClassTemplatePartialSpecializationDecl *
InstantiateClassTemplatePartialSpecialization(ClassTemplateDecl * ClassTemplate,ClassTemplatePartialSpecializationDecl * PartialSpec)2240 TemplateDeclInstantiator::InstantiateClassTemplatePartialSpecialization(
2241                                             ClassTemplateDecl *ClassTemplate,
2242                           ClassTemplatePartialSpecializationDecl *PartialSpec) {
2243   // Create a local instantiation scope for this class template partial
2244   // specialization, which will contain the instantiations of the template
2245   // parameters.
2246   LocalInstantiationScope Scope(SemaRef);
2247 
2248   // Substitute into the template parameters of the class template partial
2249   // specialization.
2250   TemplateParameterList *TempParams = PartialSpec->getTemplateParameters();
2251   TemplateParameterList *InstParams = SubstTemplateParams(TempParams);
2252   if (!InstParams)
2253     return 0;
2254 
2255   // Substitute into the template arguments of the class template partial
2256   // specialization.
2257   TemplateArgumentListInfo InstTemplateArgs; // no angle locations
2258   if (SemaRef.Subst(PartialSpec->getTemplateArgsAsWritten(),
2259                     PartialSpec->getNumTemplateArgsAsWritten(),
2260                     InstTemplateArgs, TemplateArgs))
2261     return 0;
2262 
2263   // Check that the template argument list is well-formed for this
2264   // class template.
2265   SmallVector<TemplateArgument, 4> Converted;
2266   if (SemaRef.CheckTemplateArgumentList(ClassTemplate,
2267                                         PartialSpec->getLocation(),
2268                                         InstTemplateArgs,
2269                                         false,
2270                                         Converted))
2271     return 0;
2272 
2273   // Figure out where to insert this class template partial specialization
2274   // in the member template's set of class template partial specializations.
2275   void *InsertPos = 0;
2276   ClassTemplateSpecializationDecl *PrevDecl
2277     = ClassTemplate->findPartialSpecialization(Converted.data(),
2278                                                Converted.size(), InsertPos);
2279 
2280   // Build the canonical type that describes the converted template
2281   // arguments of the class template partial specialization.
2282   QualType CanonType
2283     = SemaRef.Context.getTemplateSpecializationType(TemplateName(ClassTemplate),
2284                                                     Converted.data(),
2285                                                     Converted.size());
2286 
2287   // Build the fully-sugared type for this class template
2288   // specialization as the user wrote in the specialization
2289   // itself. This means that we'll pretty-print the type retrieved
2290   // from the specialization's declaration the way that the user
2291   // actually wrote the specialization, rather than formatting the
2292   // name based on the "canonical" representation used to store the
2293   // template arguments in the specialization.
2294   TypeSourceInfo *WrittenTy
2295     = SemaRef.Context.getTemplateSpecializationTypeInfo(
2296                                                     TemplateName(ClassTemplate),
2297                                                     PartialSpec->getLocation(),
2298                                                     InstTemplateArgs,
2299                                                     CanonType);
2300 
2301   if (PrevDecl) {
2302     // We've already seen a partial specialization with the same template
2303     // parameters and template arguments. This can happen, for example, when
2304     // substituting the outer template arguments ends up causing two
2305     // class template partial specializations of a member class template
2306     // to have identical forms, e.g.,
2307     //
2308     //   template<typename T, typename U>
2309     //   struct Outer {
2310     //     template<typename X, typename Y> struct Inner;
2311     //     template<typename Y> struct Inner<T, Y>;
2312     //     template<typename Y> struct Inner<U, Y>;
2313     //   };
2314     //
2315     //   Outer<int, int> outer; // error: the partial specializations of Inner
2316     //                          // have the same signature.
2317     SemaRef.Diag(PartialSpec->getLocation(), diag::err_partial_spec_redeclared)
2318       << WrittenTy->getType();
2319     SemaRef.Diag(PrevDecl->getLocation(), diag::note_prev_partial_spec_here)
2320       << SemaRef.Context.getTypeDeclType(PrevDecl);
2321     return 0;
2322   }
2323 
2324 
2325   // Create the class template partial specialization declaration.
2326   ClassTemplatePartialSpecializationDecl *InstPartialSpec
2327     = ClassTemplatePartialSpecializationDecl::Create(SemaRef.Context,
2328                                                      PartialSpec->getTagKind(),
2329                                                      Owner,
2330                                                      PartialSpec->getLocStart(),
2331                                                      PartialSpec->getLocation(),
2332                                                      InstParams,
2333                                                      ClassTemplate,
2334                                                      Converted.data(),
2335                                                      Converted.size(),
2336                                                      InstTemplateArgs,
2337                                                      CanonType,
2338                                                      0,
2339                              ClassTemplate->getNextPartialSpecSequenceNumber());
2340   // Substitute the nested name specifier, if any.
2341   if (SubstQualifier(PartialSpec, InstPartialSpec))
2342     return 0;
2343 
2344   InstPartialSpec->setInstantiatedFromMember(PartialSpec);
2345   InstPartialSpec->setTypeAsWritten(WrittenTy);
2346 
2347   // Add this partial specialization to the set of class template partial
2348   // specializations.
2349   ClassTemplate->AddPartialSpecialization(InstPartialSpec, /*InsertPos=*/0);
2350   return InstPartialSpec;
2351 }
2352 
2353 TypeSourceInfo*
SubstFunctionType(FunctionDecl * D,SmallVectorImpl<ParmVarDecl * > & Params)2354 TemplateDeclInstantiator::SubstFunctionType(FunctionDecl *D,
2355                               SmallVectorImpl<ParmVarDecl *> &Params) {
2356   TypeSourceInfo *OldTInfo = D->getTypeSourceInfo();
2357   assert(OldTInfo && "substituting function without type source info");
2358   assert(Params.empty() && "parameter vector is non-empty at start");
2359 
2360   CXXRecordDecl *ThisContext = 0;
2361   unsigned ThisTypeQuals = 0;
2362   if (CXXMethodDecl *Method = dyn_cast<CXXMethodDecl>(D)) {
2363     ThisContext = Method->getParent();
2364     ThisTypeQuals = Method->getTypeQualifiers();
2365   }
2366 
2367   TypeSourceInfo *NewTInfo
2368     = SemaRef.SubstFunctionDeclType(OldTInfo, TemplateArgs,
2369                                     D->getTypeSpecStartLoc(),
2370                                     D->getDeclName(),
2371                                     ThisContext, ThisTypeQuals);
2372   if (!NewTInfo)
2373     return 0;
2374 
2375   if (NewTInfo != OldTInfo) {
2376     // Get parameters from the new type info.
2377     TypeLoc OldTL = OldTInfo->getTypeLoc().IgnoreParens();
2378     if (FunctionProtoTypeLoc OldProtoLoc =
2379             OldTL.getAs<FunctionProtoTypeLoc>()) {
2380       TypeLoc NewTL = NewTInfo->getTypeLoc().IgnoreParens();
2381       FunctionProtoTypeLoc NewProtoLoc = NewTL.castAs<FunctionProtoTypeLoc>();
2382       unsigned NewIdx = 0;
2383       for (unsigned OldIdx = 0, NumOldParams = OldProtoLoc.getNumArgs();
2384            OldIdx != NumOldParams; ++OldIdx) {
2385         ParmVarDecl *OldParam = OldProtoLoc.getArg(OldIdx);
2386         LocalInstantiationScope *Scope = SemaRef.CurrentInstantiationScope;
2387 
2388         Optional<unsigned> NumArgumentsInExpansion;
2389         if (OldParam->isParameterPack())
2390           NumArgumentsInExpansion =
2391               SemaRef.getNumArgumentsInExpansion(OldParam->getType(),
2392                                                  TemplateArgs);
2393         if (!NumArgumentsInExpansion) {
2394           // Simple case: normal parameter, or a parameter pack that's
2395           // instantiated to a (still-dependent) parameter pack.
2396           ParmVarDecl *NewParam = NewProtoLoc.getArg(NewIdx++);
2397           Params.push_back(NewParam);
2398           Scope->InstantiatedLocal(OldParam, NewParam);
2399         } else {
2400           // Parameter pack expansion: make the instantiation an argument pack.
2401           Scope->MakeInstantiatedLocalArgPack(OldParam);
2402           for (unsigned I = 0; I != *NumArgumentsInExpansion; ++I) {
2403             ParmVarDecl *NewParam = NewProtoLoc.getArg(NewIdx++);
2404             Params.push_back(NewParam);
2405             Scope->InstantiatedLocalPackArg(OldParam, NewParam);
2406           }
2407         }
2408       }
2409     }
2410   } else {
2411     // The function type itself was not dependent and therefore no
2412     // substitution occurred. However, we still need to instantiate
2413     // the function parameters themselves.
2414     TypeLoc OldTL = OldTInfo->getTypeLoc().IgnoreParens();
2415     if (FunctionProtoTypeLoc OldProtoLoc =
2416             OldTL.getAs<FunctionProtoTypeLoc>()) {
2417       for (unsigned i = 0, i_end = OldProtoLoc.getNumArgs(); i != i_end; ++i) {
2418         ParmVarDecl *Parm = VisitParmVarDecl(OldProtoLoc.getArg(i));
2419         if (!Parm)
2420           return 0;
2421         Params.push_back(Parm);
2422       }
2423     }
2424   }
2425   return NewTInfo;
2426 }
2427 
2428 /// Introduce the instantiated function parameters into the local
2429 /// instantiation scope, and set the parameter names to those used
2430 /// in the template.
addInstantiatedParametersToScope(Sema & S,FunctionDecl * Function,const FunctionDecl * PatternDecl,LocalInstantiationScope & Scope,const MultiLevelTemplateArgumentList & TemplateArgs)2431 static void addInstantiatedParametersToScope(Sema &S, FunctionDecl *Function,
2432                                              const FunctionDecl *PatternDecl,
2433                                              LocalInstantiationScope &Scope,
2434                            const MultiLevelTemplateArgumentList &TemplateArgs) {
2435   unsigned FParamIdx = 0;
2436   for (unsigned I = 0, N = PatternDecl->getNumParams(); I != N; ++I) {
2437     const ParmVarDecl *PatternParam = PatternDecl->getParamDecl(I);
2438     if (!PatternParam->isParameterPack()) {
2439       // Simple case: not a parameter pack.
2440       assert(FParamIdx < Function->getNumParams());
2441       ParmVarDecl *FunctionParam = Function->getParamDecl(FParamIdx);
2442       FunctionParam->setDeclName(PatternParam->getDeclName());
2443       Scope.InstantiatedLocal(PatternParam, FunctionParam);
2444       ++FParamIdx;
2445       continue;
2446     }
2447 
2448     // Expand the parameter pack.
2449     Scope.MakeInstantiatedLocalArgPack(PatternParam);
2450     Optional<unsigned> NumArgumentsInExpansion
2451       = S.getNumArgumentsInExpansion(PatternParam->getType(), TemplateArgs);
2452     assert(NumArgumentsInExpansion &&
2453            "should only be called when all template arguments are known");
2454     for (unsigned Arg = 0; Arg < *NumArgumentsInExpansion; ++Arg) {
2455       ParmVarDecl *FunctionParam = Function->getParamDecl(FParamIdx);
2456       FunctionParam->setDeclName(PatternParam->getDeclName());
2457       Scope.InstantiatedLocalPackArg(PatternParam, FunctionParam);
2458       ++FParamIdx;
2459     }
2460   }
2461 }
2462 
InstantiateExceptionSpec(Sema & SemaRef,FunctionDecl * New,const FunctionProtoType * Proto,const MultiLevelTemplateArgumentList & TemplateArgs)2463 static void InstantiateExceptionSpec(Sema &SemaRef, FunctionDecl *New,
2464                                      const FunctionProtoType *Proto,
2465                            const MultiLevelTemplateArgumentList &TemplateArgs) {
2466   assert(Proto->getExceptionSpecType() != EST_Uninstantiated);
2467 
2468   // C++11 [expr.prim.general]p3:
2469   //   If a declaration declares a member function or member function
2470   //   template of a class X, the expression this is a prvalue of type
2471   //   "pointer to cv-qualifier-seq X" between the optional cv-qualifer-seq
2472   //   and the end of the function-definition, member-declarator, or
2473   //   declarator.
2474   CXXRecordDecl *ThisContext = 0;
2475   unsigned ThisTypeQuals = 0;
2476   if (CXXMethodDecl *Method = dyn_cast<CXXMethodDecl>(New)) {
2477     ThisContext = Method->getParent();
2478     ThisTypeQuals = Method->getTypeQualifiers();
2479   }
2480   Sema::CXXThisScopeRAII ThisScope(SemaRef, ThisContext, ThisTypeQuals,
2481                                    SemaRef.getLangOpts().CPlusPlus11);
2482 
2483   // The function has an exception specification or a "noreturn"
2484   // attribute. Substitute into each of the exception types.
2485   SmallVector<QualType, 4> Exceptions;
2486   for (unsigned I = 0, N = Proto->getNumExceptions(); I != N; ++I) {
2487     // FIXME: Poor location information!
2488     if (const PackExpansionType *PackExpansion
2489           = Proto->getExceptionType(I)->getAs<PackExpansionType>()) {
2490       // We have a pack expansion. Instantiate it.
2491       SmallVector<UnexpandedParameterPack, 2> Unexpanded;
2492       SemaRef.collectUnexpandedParameterPacks(PackExpansion->getPattern(),
2493                                               Unexpanded);
2494       assert(!Unexpanded.empty() &&
2495              "Pack expansion without parameter packs?");
2496 
2497       bool Expand = false;
2498       bool RetainExpansion = false;
2499       Optional<unsigned> NumExpansions
2500                                         = PackExpansion->getNumExpansions();
2501       if (SemaRef.CheckParameterPacksForExpansion(New->getLocation(),
2502                                                   SourceRange(),
2503                                                   Unexpanded,
2504                                                   TemplateArgs,
2505                                                   Expand,
2506                                                   RetainExpansion,
2507                                                   NumExpansions))
2508         break;
2509 
2510       if (!Expand) {
2511         // We can't expand this pack expansion into separate arguments yet;
2512         // just substitute into the pattern and create a new pack expansion
2513         // type.
2514         Sema::ArgumentPackSubstitutionIndexRAII SubstIndex(SemaRef, -1);
2515         QualType T = SemaRef.SubstType(PackExpansion->getPattern(),
2516                                        TemplateArgs,
2517                                      New->getLocation(), New->getDeclName());
2518         if (T.isNull())
2519           break;
2520 
2521         T = SemaRef.Context.getPackExpansionType(T, NumExpansions);
2522         Exceptions.push_back(T);
2523         continue;
2524       }
2525 
2526       // Substitute into the pack expansion pattern for each template
2527       bool Invalid = false;
2528       for (unsigned ArgIdx = 0; ArgIdx != *NumExpansions; ++ArgIdx) {
2529         Sema::ArgumentPackSubstitutionIndexRAII SubstIndex(SemaRef, ArgIdx);
2530 
2531         QualType T = SemaRef.SubstType(PackExpansion->getPattern(),
2532                                        TemplateArgs,
2533                                      New->getLocation(), New->getDeclName());
2534         if (T.isNull()) {
2535           Invalid = true;
2536           break;
2537         }
2538 
2539         Exceptions.push_back(T);
2540       }
2541 
2542       if (Invalid)
2543         break;
2544 
2545       continue;
2546     }
2547 
2548     QualType T
2549       = SemaRef.SubstType(Proto->getExceptionType(I), TemplateArgs,
2550                           New->getLocation(), New->getDeclName());
2551     if (T.isNull() ||
2552         SemaRef.CheckSpecifiedExceptionType(T, New->getLocation()))
2553       continue;
2554 
2555     Exceptions.push_back(T);
2556   }
2557   Expr *NoexceptExpr = 0;
2558   if (Expr *OldNoexceptExpr = Proto->getNoexceptExpr()) {
2559     EnterExpressionEvaluationContext Unevaluated(SemaRef,
2560                                                  Sema::ConstantEvaluated);
2561     ExprResult E = SemaRef.SubstExpr(OldNoexceptExpr, TemplateArgs);
2562     if (E.isUsable())
2563       E = SemaRef.CheckBooleanCondition(E.get(), E.get()->getLocStart());
2564 
2565     if (E.isUsable()) {
2566       NoexceptExpr = E.take();
2567       if (!NoexceptExpr->isTypeDependent() &&
2568           !NoexceptExpr->isValueDependent())
2569         NoexceptExpr
2570           = SemaRef.VerifyIntegerConstantExpression(NoexceptExpr,
2571               0, diag::err_noexcept_needs_constant_expression,
2572               /*AllowFold*/ false).take();
2573     }
2574   }
2575 
2576   // Rebuild the function type
2577   const FunctionProtoType *NewProto
2578     = New->getType()->getAs<FunctionProtoType>();
2579   assert(NewProto && "Template instantiation without function prototype?");
2580 
2581   FunctionProtoType::ExtProtoInfo EPI = NewProto->getExtProtoInfo();
2582   EPI.ExceptionSpecType = Proto->getExceptionSpecType();
2583   EPI.NumExceptions = Exceptions.size();
2584   EPI.Exceptions = Exceptions.data();
2585   EPI.NoexceptExpr = NoexceptExpr;
2586 
2587   New->setType(SemaRef.Context.getFunctionType(NewProto->getResultType(),
2588                                   ArrayRef<QualType>(NewProto->arg_type_begin(),
2589                                                      NewProto->getNumArgs()),
2590                                                EPI));
2591 }
2592 
InstantiateExceptionSpec(SourceLocation PointOfInstantiation,FunctionDecl * Decl)2593 void Sema::InstantiateExceptionSpec(SourceLocation PointOfInstantiation,
2594                                     FunctionDecl *Decl) {
2595   const FunctionProtoType *Proto = Decl->getType()->castAs<FunctionProtoType>();
2596   if (Proto->getExceptionSpecType() != EST_Uninstantiated)
2597     return;
2598 
2599   InstantiatingTemplate Inst(*this, PointOfInstantiation, Decl,
2600                              InstantiatingTemplate::ExceptionSpecification());
2601   if (Inst) {
2602     // We hit the instantiation depth limit. Clear the exception specification
2603     // so that our callers don't have to cope with EST_Uninstantiated.
2604     FunctionProtoType::ExtProtoInfo EPI = Proto->getExtProtoInfo();
2605     EPI.ExceptionSpecType = EST_None;
2606     Decl->setType(Context.getFunctionType(Proto->getResultType(),
2607                                     ArrayRef<QualType>(Proto->arg_type_begin(),
2608                                                        Proto->getNumArgs()),
2609                                           EPI));
2610     return;
2611   }
2612 
2613   // Enter the scope of this instantiation. We don't use
2614   // PushDeclContext because we don't have a scope.
2615   Sema::ContextRAII savedContext(*this, Decl);
2616   LocalInstantiationScope Scope(*this);
2617 
2618   MultiLevelTemplateArgumentList TemplateArgs =
2619     getTemplateInstantiationArgs(Decl, 0, /*RelativeToPrimary*/true);
2620 
2621   FunctionDecl *Template = Proto->getExceptionSpecTemplate();
2622   addInstantiatedParametersToScope(*this, Decl, Template, Scope, TemplateArgs);
2623 
2624   ::InstantiateExceptionSpec(*this, Decl,
2625                              Template->getType()->castAs<FunctionProtoType>(),
2626                              TemplateArgs);
2627 }
2628 
2629 /// \brief Initializes the common fields of an instantiation function
2630 /// declaration (New) from the corresponding fields of its template (Tmpl).
2631 ///
2632 /// \returns true if there was an error
2633 bool
InitFunctionInstantiation(FunctionDecl * New,FunctionDecl * Tmpl)2634 TemplateDeclInstantiator::InitFunctionInstantiation(FunctionDecl *New,
2635                                                     FunctionDecl *Tmpl) {
2636   if (Tmpl->isDeleted())
2637     New->setDeletedAsWritten();
2638 
2639   // If we are performing substituting explicitly-specified template arguments
2640   // or deduced template arguments into a function template and we reach this
2641   // point, we are now past the point where SFINAE applies and have committed
2642   // to keeping the new function template specialization. We therefore
2643   // convert the active template instantiation for the function template
2644   // into a template instantiation for this specific function template
2645   // specialization, which is not a SFINAE context, so that we diagnose any
2646   // further errors in the declaration itself.
2647   typedef Sema::ActiveTemplateInstantiation ActiveInstType;
2648   ActiveInstType &ActiveInst = SemaRef.ActiveTemplateInstantiations.back();
2649   if (ActiveInst.Kind == ActiveInstType::ExplicitTemplateArgumentSubstitution ||
2650       ActiveInst.Kind == ActiveInstType::DeducedTemplateArgumentSubstitution) {
2651     if (FunctionTemplateDecl *FunTmpl
2652           = dyn_cast<FunctionTemplateDecl>(ActiveInst.Entity)) {
2653       assert(FunTmpl->getTemplatedDecl() == Tmpl &&
2654              "Deduction from the wrong function template?");
2655       (void) FunTmpl;
2656       ActiveInst.Kind = ActiveInstType::TemplateInstantiation;
2657       ActiveInst.Entity = New;
2658     }
2659   }
2660 
2661   const FunctionProtoType *Proto = Tmpl->getType()->getAs<FunctionProtoType>();
2662   assert(Proto && "Function template without prototype?");
2663 
2664   if (Proto->hasExceptionSpec() || Proto->getNoReturnAttr()) {
2665     FunctionProtoType::ExtProtoInfo EPI = Proto->getExtProtoInfo();
2666 
2667     // DR1330: In C++11, defer instantiation of a non-trivial
2668     // exception specification.
2669     if (SemaRef.getLangOpts().CPlusPlus11 &&
2670         EPI.ExceptionSpecType != EST_None &&
2671         EPI.ExceptionSpecType != EST_DynamicNone &&
2672         EPI.ExceptionSpecType != EST_BasicNoexcept) {
2673       FunctionDecl *ExceptionSpecTemplate = Tmpl;
2674       if (EPI.ExceptionSpecType == EST_Uninstantiated)
2675         ExceptionSpecTemplate = EPI.ExceptionSpecTemplate;
2676       assert(EPI.ExceptionSpecType != EST_Unevaluated &&
2677              "instantiating implicitly-declared special member");
2678 
2679       // Mark the function has having an uninstantiated exception specification.
2680       const FunctionProtoType *NewProto
2681         = New->getType()->getAs<FunctionProtoType>();
2682       assert(NewProto && "Template instantiation without function prototype?");
2683       EPI = NewProto->getExtProtoInfo();
2684       EPI.ExceptionSpecType = EST_Uninstantiated;
2685       EPI.ExceptionSpecDecl = New;
2686       EPI.ExceptionSpecTemplate = ExceptionSpecTemplate;
2687       New->setType(SemaRef.Context.getFunctionType(NewProto->getResultType(),
2688                                   ArrayRef<QualType>(NewProto->arg_type_begin(),
2689                                                      NewProto->getNumArgs()),
2690                                                    EPI));
2691     } else {
2692       ::InstantiateExceptionSpec(SemaRef, New, Proto, TemplateArgs);
2693     }
2694   }
2695 
2696   // Get the definition. Leaves the variable unchanged if undefined.
2697   const FunctionDecl *Definition = Tmpl;
2698   Tmpl->isDefined(Definition);
2699 
2700   SemaRef.InstantiateAttrs(TemplateArgs, Definition, New,
2701                            LateAttrs, StartingScope);
2702 
2703   return false;
2704 }
2705 
2706 /// \brief Initializes common fields of an instantiated method
2707 /// declaration (New) from the corresponding fields of its template
2708 /// (Tmpl).
2709 ///
2710 /// \returns true if there was an error
2711 bool
InitMethodInstantiation(CXXMethodDecl * New,CXXMethodDecl * Tmpl)2712 TemplateDeclInstantiator::InitMethodInstantiation(CXXMethodDecl *New,
2713                                                   CXXMethodDecl *Tmpl) {
2714   if (InitFunctionInstantiation(New, Tmpl))
2715     return true;
2716 
2717   New->setAccess(Tmpl->getAccess());
2718   if (Tmpl->isVirtualAsWritten())
2719     New->setVirtualAsWritten(true);
2720 
2721   // FIXME: attributes
2722   // FIXME: New needs a pointer to Tmpl
2723   return false;
2724 }
2725 
2726 /// \brief Instantiate the definition of the given function from its
2727 /// template.
2728 ///
2729 /// \param PointOfInstantiation the point at which the instantiation was
2730 /// required. Note that this is not precisely a "point of instantiation"
2731 /// for the function, but it's close.
2732 ///
2733 /// \param Function the already-instantiated declaration of a
2734 /// function template specialization or member function of a class template
2735 /// specialization.
2736 ///
2737 /// \param Recursive if true, recursively instantiates any functions that
2738 /// are required by this instantiation.
2739 ///
2740 /// \param DefinitionRequired if true, then we are performing an explicit
2741 /// instantiation where the body of the function is required. Complain if
2742 /// there is no such body.
InstantiateFunctionDefinition(SourceLocation PointOfInstantiation,FunctionDecl * Function,bool Recursive,bool DefinitionRequired)2743 void Sema::InstantiateFunctionDefinition(SourceLocation PointOfInstantiation,
2744                                          FunctionDecl *Function,
2745                                          bool Recursive,
2746                                          bool DefinitionRequired) {
2747   if (Function->isInvalidDecl() || Function->isDefined())
2748     return;
2749 
2750   // Never instantiate an explicit specialization except if it is a class scope
2751   // explicit specialization.
2752   if (Function->getTemplateSpecializationKind() == TSK_ExplicitSpecialization &&
2753       !Function->getClassScopeSpecializationPattern())
2754     return;
2755 
2756   // Find the function body that we'll be substituting.
2757   const FunctionDecl *PatternDecl = Function->getTemplateInstantiationPattern();
2758   assert(PatternDecl && "instantiating a non-template");
2759 
2760   Stmt *Pattern = PatternDecl->getBody(PatternDecl);
2761   assert(PatternDecl && "template definition is not a template");
2762   if (!Pattern) {
2763     // Try to find a defaulted definition
2764     PatternDecl->isDefined(PatternDecl);
2765   }
2766   assert(PatternDecl && "template definition is not a template");
2767 
2768   // Postpone late parsed template instantiations.
2769   if (PatternDecl->isLateTemplateParsed() &&
2770       !LateTemplateParser) {
2771     PendingInstantiations.push_back(
2772       std::make_pair(Function, PointOfInstantiation));
2773     return;
2774   }
2775 
2776   // Call the LateTemplateParser callback if there a need to late parse
2777   // a templated function definition.
2778   if (!Pattern && PatternDecl->isLateTemplateParsed() &&
2779       LateTemplateParser) {
2780     LateTemplateParser(OpaqueParser, PatternDecl);
2781     Pattern = PatternDecl->getBody(PatternDecl);
2782   }
2783 
2784   if (!Pattern && !PatternDecl->isDefaulted()) {
2785     if (DefinitionRequired) {
2786       if (Function->getPrimaryTemplate())
2787         Diag(PointOfInstantiation,
2788              diag::err_explicit_instantiation_undefined_func_template)
2789           << Function->getPrimaryTemplate();
2790       else
2791         Diag(PointOfInstantiation,
2792              diag::err_explicit_instantiation_undefined_member)
2793           << 1 << Function->getDeclName() << Function->getDeclContext();
2794 
2795       if (PatternDecl)
2796         Diag(PatternDecl->getLocation(),
2797              diag::note_explicit_instantiation_here);
2798       Function->setInvalidDecl();
2799     } else if (Function->getTemplateSpecializationKind()
2800                  == TSK_ExplicitInstantiationDefinition) {
2801       PendingInstantiations.push_back(
2802         std::make_pair(Function, PointOfInstantiation));
2803     }
2804 
2805     return;
2806   }
2807 
2808   // C++0x [temp.explicit]p9:
2809   //   Except for inline functions, other explicit instantiation declarations
2810   //   have the effect of suppressing the implicit instantiation of the entity
2811   //   to which they refer.
2812   if (Function->getTemplateSpecializationKind()
2813         == TSK_ExplicitInstantiationDeclaration &&
2814       !PatternDecl->isInlined())
2815     return;
2816 
2817   if (PatternDecl->isInlined())
2818     Function->setImplicitlyInline();
2819 
2820   InstantiatingTemplate Inst(*this, PointOfInstantiation, Function);
2821   if (Inst)
2822     return;
2823 
2824   // Copy the inner loc start from the pattern.
2825   Function->setInnerLocStart(PatternDecl->getInnerLocStart());
2826 
2827   // If we're performing recursive template instantiation, create our own
2828   // queue of pending implicit instantiations that we will instantiate later,
2829   // while we're still within our own instantiation context.
2830   SmallVector<VTableUse, 16> SavedVTableUses;
2831   std::deque<PendingImplicitInstantiation> SavedPendingInstantiations;
2832   if (Recursive) {
2833     VTableUses.swap(SavedVTableUses);
2834     PendingInstantiations.swap(SavedPendingInstantiations);
2835   }
2836 
2837   EnterExpressionEvaluationContext EvalContext(*this,
2838                                                Sema::PotentiallyEvaluated);
2839 
2840   // Introduce a new scope where local variable instantiations will be
2841   // recorded, unless we're actually a member function within a local
2842   // class, in which case we need to merge our results with the parent
2843   // scope (of the enclosing function).
2844   bool MergeWithParentScope = false;
2845   if (CXXRecordDecl *Rec = dyn_cast<CXXRecordDecl>(Function->getDeclContext()))
2846     MergeWithParentScope = Rec->isLocalClass();
2847 
2848   LocalInstantiationScope Scope(*this, MergeWithParentScope);
2849 
2850   if (PatternDecl->isDefaulted())
2851     SetDeclDefaulted(Function, PatternDecl->getLocation());
2852   else {
2853     ActOnStartOfFunctionDef(0, Function);
2854 
2855     // Enter the scope of this instantiation. We don't use
2856     // PushDeclContext because we don't have a scope.
2857     Sema::ContextRAII savedContext(*this, Function);
2858 
2859     MultiLevelTemplateArgumentList TemplateArgs =
2860       getTemplateInstantiationArgs(Function, 0, false, PatternDecl);
2861 
2862     addInstantiatedParametersToScope(*this, Function, PatternDecl, Scope,
2863                                      TemplateArgs);
2864 
2865     // If this is a constructor, instantiate the member initializers.
2866     if (const CXXConstructorDecl *Ctor =
2867           dyn_cast<CXXConstructorDecl>(PatternDecl)) {
2868       InstantiateMemInitializers(cast<CXXConstructorDecl>(Function), Ctor,
2869                                  TemplateArgs);
2870     }
2871 
2872     // Instantiate the function body.
2873     StmtResult Body = SubstStmt(Pattern, TemplateArgs);
2874 
2875     if (Body.isInvalid())
2876       Function->setInvalidDecl();
2877 
2878     ActOnFinishFunctionBody(Function, Body.get(),
2879                             /*IsInstantiation=*/true);
2880 
2881     PerformDependentDiagnostics(PatternDecl, TemplateArgs);
2882 
2883     savedContext.pop();
2884   }
2885 
2886   DeclGroupRef DG(Function);
2887   Consumer.HandleTopLevelDecl(DG);
2888 
2889   // This class may have local implicit instantiations that need to be
2890   // instantiation within this scope.
2891   PerformPendingInstantiations(/*LocalOnly=*/true);
2892   Scope.Exit();
2893 
2894   if (Recursive) {
2895     // Define any pending vtables.
2896     DefineUsedVTables();
2897 
2898     // Instantiate any pending implicit instantiations found during the
2899     // instantiation of this template.
2900     PerformPendingInstantiations();
2901 
2902     // Restore the set of pending vtables.
2903     assert(VTableUses.empty() &&
2904            "VTableUses should be empty before it is discarded.");
2905     VTableUses.swap(SavedVTableUses);
2906 
2907     // Restore the set of pending implicit instantiations.
2908     assert(PendingInstantiations.empty() &&
2909            "PendingInstantiations should be empty before it is discarded.");
2910     PendingInstantiations.swap(SavedPendingInstantiations);
2911   }
2912 }
2913 
2914 /// \brief Instantiate the definition of the given variable from its
2915 /// template.
2916 ///
2917 /// \param PointOfInstantiation the point at which the instantiation was
2918 /// required. Note that this is not precisely a "point of instantiation"
2919 /// for the function, but it's close.
2920 ///
2921 /// \param Var the already-instantiated declaration of a static member
2922 /// variable of a class template specialization.
2923 ///
2924 /// \param Recursive if true, recursively instantiates any functions that
2925 /// are required by this instantiation.
2926 ///
2927 /// \param DefinitionRequired if true, then we are performing an explicit
2928 /// instantiation where an out-of-line definition of the member variable
2929 /// is required. Complain if there is no such definition.
InstantiateStaticDataMemberDefinition(SourceLocation PointOfInstantiation,VarDecl * Var,bool Recursive,bool DefinitionRequired)2930 void Sema::InstantiateStaticDataMemberDefinition(
2931                                           SourceLocation PointOfInstantiation,
2932                                                  VarDecl *Var,
2933                                                  bool Recursive,
2934                                                  bool DefinitionRequired) {
2935   if (Var->isInvalidDecl())
2936     return;
2937 
2938   // Find the out-of-line definition of this static data member.
2939   VarDecl *Def = Var->getInstantiatedFromStaticDataMember();
2940   assert(Def && "This data member was not instantiated from a template?");
2941   assert(Def->isStaticDataMember() && "Not a static data member?");
2942   Def = Def->getOutOfLineDefinition();
2943 
2944   if (!Def) {
2945     // We did not find an out-of-line definition of this static data member,
2946     // so we won't perform any instantiation. Rather, we rely on the user to
2947     // instantiate this definition (or provide a specialization for it) in
2948     // another translation unit.
2949     if (DefinitionRequired) {
2950       Def = Var->getInstantiatedFromStaticDataMember();
2951       Diag(PointOfInstantiation,
2952            diag::err_explicit_instantiation_undefined_member)
2953         << 2 << Var->getDeclName() << Var->getDeclContext();
2954       Diag(Def->getLocation(), diag::note_explicit_instantiation_here);
2955     } else if (Var->getTemplateSpecializationKind()
2956                  == TSK_ExplicitInstantiationDefinition) {
2957       PendingInstantiations.push_back(
2958         std::make_pair(Var, PointOfInstantiation));
2959     }
2960 
2961     return;
2962   }
2963 
2964   TemplateSpecializationKind TSK = Var->getTemplateSpecializationKind();
2965 
2966   // Never instantiate an explicit specialization.
2967   if (TSK == TSK_ExplicitSpecialization)
2968     return;
2969 
2970   // C++0x [temp.explicit]p9:
2971   //   Except for inline functions, other explicit instantiation declarations
2972   //   have the effect of suppressing the implicit instantiation of the entity
2973   //   to which they refer.
2974   if (TSK == TSK_ExplicitInstantiationDeclaration)
2975     return;
2976 
2977   // Make sure to pass the instantiated variable to the consumer at the end.
2978   struct PassToConsumerRAII {
2979     ASTConsumer &Consumer;
2980     VarDecl *Var;
2981 
2982     PassToConsumerRAII(ASTConsumer &Consumer, VarDecl *Var)
2983       : Consumer(Consumer), Var(Var) { }
2984 
2985     ~PassToConsumerRAII() {
2986       Consumer.HandleCXXStaticMemberVarInstantiation(Var);
2987     }
2988   } PassToConsumerRAII(Consumer, Var);
2989 
2990   // If we already have a definition, we're done.
2991   if (VarDecl *Def = Var->getDefinition()) {
2992     // We may be explicitly instantiating something we've already implicitly
2993     // instantiated.
2994     Def->setTemplateSpecializationKind(Var->getTemplateSpecializationKind(),
2995                                        PointOfInstantiation);
2996     return;
2997   }
2998 
2999   InstantiatingTemplate Inst(*this, PointOfInstantiation, Var);
3000   if (Inst)
3001     return;
3002 
3003   // If we're performing recursive template instantiation, create our own
3004   // queue of pending implicit instantiations that we will instantiate later,
3005   // while we're still within our own instantiation context.
3006   SmallVector<VTableUse, 16> SavedVTableUses;
3007   std::deque<PendingImplicitInstantiation> SavedPendingInstantiations;
3008   if (Recursive) {
3009     VTableUses.swap(SavedVTableUses);
3010     PendingInstantiations.swap(SavedPendingInstantiations);
3011   }
3012 
3013   // Enter the scope of this instantiation. We don't use
3014   // PushDeclContext because we don't have a scope.
3015   ContextRAII previousContext(*this, Var->getDeclContext());
3016   LocalInstantiationScope Local(*this);
3017 
3018   VarDecl *OldVar = Var;
3019   Var = cast_or_null<VarDecl>(SubstDecl(Def, Var->getDeclContext(),
3020                                         getTemplateInstantiationArgs(Var)));
3021 
3022   previousContext.pop();
3023 
3024   if (Var) {
3025     PassToConsumerRAII.Var = Var;
3026     MemberSpecializationInfo *MSInfo = OldVar->getMemberSpecializationInfo();
3027     assert(MSInfo && "Missing member specialization information?");
3028     Var->setTemplateSpecializationKind(MSInfo->getTemplateSpecializationKind(),
3029                                        MSInfo->getPointOfInstantiation());
3030   }
3031   Local.Exit();
3032 
3033   if (Recursive) {
3034     // Define any newly required vtables.
3035     DefineUsedVTables();
3036 
3037     // Instantiate any pending implicit instantiations found during the
3038     // instantiation of this template.
3039     PerformPendingInstantiations();
3040 
3041     // Restore the set of pending vtables.
3042     assert(VTableUses.empty() &&
3043            "VTableUses should be empty before it is discarded, "
3044            "while instantiating static data member.");
3045     VTableUses.swap(SavedVTableUses);
3046 
3047     // Restore the set of pending implicit instantiations.
3048     assert(PendingInstantiations.empty() &&
3049            "PendingInstantiations should be empty before it is discarded, "
3050            "while instantiating static data member.");
3051     PendingInstantiations.swap(SavedPendingInstantiations);
3052   }
3053 }
3054 
3055 void
InstantiateMemInitializers(CXXConstructorDecl * New,const CXXConstructorDecl * Tmpl,const MultiLevelTemplateArgumentList & TemplateArgs)3056 Sema::InstantiateMemInitializers(CXXConstructorDecl *New,
3057                                  const CXXConstructorDecl *Tmpl,
3058                            const MultiLevelTemplateArgumentList &TemplateArgs) {
3059 
3060   SmallVector<CXXCtorInitializer*, 4> NewInits;
3061   bool AnyErrors = Tmpl->isInvalidDecl();
3062 
3063   // Instantiate all the initializers.
3064   for (CXXConstructorDecl::init_const_iterator Inits = Tmpl->init_begin(),
3065                                             InitsEnd = Tmpl->init_end();
3066        Inits != InitsEnd; ++Inits) {
3067     CXXCtorInitializer *Init = *Inits;
3068 
3069     // Only instantiate written initializers, let Sema re-construct implicit
3070     // ones.
3071     if (!Init->isWritten())
3072       continue;
3073 
3074     SourceLocation EllipsisLoc;
3075 
3076     if (Init->isPackExpansion()) {
3077       // This is a pack expansion. We should expand it now.
3078       TypeLoc BaseTL = Init->getTypeSourceInfo()->getTypeLoc();
3079       SmallVector<UnexpandedParameterPack, 2> Unexpanded;
3080       collectUnexpandedParameterPacks(BaseTL, Unexpanded);
3081       bool ShouldExpand = false;
3082       bool RetainExpansion = false;
3083       Optional<unsigned> NumExpansions;
3084       if (CheckParameterPacksForExpansion(Init->getEllipsisLoc(),
3085                                           BaseTL.getSourceRange(),
3086                                           Unexpanded,
3087                                           TemplateArgs, ShouldExpand,
3088                                           RetainExpansion,
3089                                           NumExpansions)) {
3090         AnyErrors = true;
3091         New->setInvalidDecl();
3092         continue;
3093       }
3094       assert(ShouldExpand && "Partial instantiation of base initializer?");
3095 
3096       // Loop over all of the arguments in the argument pack(s),
3097       for (unsigned I = 0; I != *NumExpansions; ++I) {
3098         Sema::ArgumentPackSubstitutionIndexRAII SubstIndex(*this, I);
3099 
3100         // Instantiate the initializer.
3101         ExprResult TempInit = SubstInitializer(Init->getInit(), TemplateArgs,
3102                                                /*CXXDirectInit=*/true);
3103         if (TempInit.isInvalid()) {
3104           AnyErrors = true;
3105           break;
3106         }
3107 
3108         // Instantiate the base type.
3109         TypeSourceInfo *BaseTInfo = SubstType(Init->getTypeSourceInfo(),
3110                                               TemplateArgs,
3111                                               Init->getSourceLocation(),
3112                                               New->getDeclName());
3113         if (!BaseTInfo) {
3114           AnyErrors = true;
3115           break;
3116         }
3117 
3118         // Build the initializer.
3119         MemInitResult NewInit = BuildBaseInitializer(BaseTInfo->getType(),
3120                                                      BaseTInfo, TempInit.take(),
3121                                                      New->getParent(),
3122                                                      SourceLocation());
3123         if (NewInit.isInvalid()) {
3124           AnyErrors = true;
3125           break;
3126         }
3127 
3128         NewInits.push_back(NewInit.get());
3129       }
3130 
3131       continue;
3132     }
3133 
3134     // Instantiate the initializer.
3135     ExprResult TempInit = SubstInitializer(Init->getInit(), TemplateArgs,
3136                                            /*CXXDirectInit=*/true);
3137     if (TempInit.isInvalid()) {
3138       AnyErrors = true;
3139       continue;
3140     }
3141 
3142     MemInitResult NewInit;
3143     if (Init->isDelegatingInitializer() || Init->isBaseInitializer()) {
3144       TypeSourceInfo *TInfo = SubstType(Init->getTypeSourceInfo(),
3145                                         TemplateArgs,
3146                                         Init->getSourceLocation(),
3147                                         New->getDeclName());
3148       if (!TInfo) {
3149         AnyErrors = true;
3150         New->setInvalidDecl();
3151         continue;
3152       }
3153 
3154       if (Init->isBaseInitializer())
3155         NewInit = BuildBaseInitializer(TInfo->getType(), TInfo, TempInit.take(),
3156                                        New->getParent(), EllipsisLoc);
3157       else
3158         NewInit = BuildDelegatingInitializer(TInfo, TempInit.take(),
3159                                   cast<CXXRecordDecl>(CurContext->getParent()));
3160     } else if (Init->isMemberInitializer()) {
3161       FieldDecl *Member = cast_or_null<FieldDecl>(FindInstantiatedDecl(
3162                                                      Init->getMemberLocation(),
3163                                                      Init->getMember(),
3164                                                      TemplateArgs));
3165       if (!Member) {
3166         AnyErrors = true;
3167         New->setInvalidDecl();
3168         continue;
3169       }
3170 
3171       NewInit = BuildMemberInitializer(Member, TempInit.take(),
3172                                        Init->getSourceLocation());
3173     } else if (Init->isIndirectMemberInitializer()) {
3174       IndirectFieldDecl *IndirectMember =
3175          cast_or_null<IndirectFieldDecl>(FindInstantiatedDecl(
3176                                  Init->getMemberLocation(),
3177                                  Init->getIndirectMember(), TemplateArgs));
3178 
3179       if (!IndirectMember) {
3180         AnyErrors = true;
3181         New->setInvalidDecl();
3182         continue;
3183       }
3184 
3185       NewInit = BuildMemberInitializer(IndirectMember, TempInit.take(),
3186                                        Init->getSourceLocation());
3187     }
3188 
3189     if (NewInit.isInvalid()) {
3190       AnyErrors = true;
3191       New->setInvalidDecl();
3192     } else {
3193       NewInits.push_back(NewInit.get());
3194     }
3195   }
3196 
3197   // Assign all the initializers to the new constructor.
3198   ActOnMemInitializers(New,
3199                        /*FIXME: ColonLoc */
3200                        SourceLocation(),
3201                        NewInits,
3202                        AnyErrors);
3203 }
3204 
3205 // TODO: this could be templated if the various decl types used the
3206 // same method name.
isInstantiationOf(ClassTemplateDecl * Pattern,ClassTemplateDecl * Instance)3207 static bool isInstantiationOf(ClassTemplateDecl *Pattern,
3208                               ClassTemplateDecl *Instance) {
3209   Pattern = Pattern->getCanonicalDecl();
3210 
3211   do {
3212     Instance = Instance->getCanonicalDecl();
3213     if (Pattern == Instance) return true;
3214     Instance = Instance->getInstantiatedFromMemberTemplate();
3215   } while (Instance);
3216 
3217   return false;
3218 }
3219 
isInstantiationOf(FunctionTemplateDecl * Pattern,FunctionTemplateDecl * Instance)3220 static bool isInstantiationOf(FunctionTemplateDecl *Pattern,
3221                               FunctionTemplateDecl *Instance) {
3222   Pattern = Pattern->getCanonicalDecl();
3223 
3224   do {
3225     Instance = Instance->getCanonicalDecl();
3226     if (Pattern == Instance) return true;
3227     Instance = Instance->getInstantiatedFromMemberTemplate();
3228   } while (Instance);
3229 
3230   return false;
3231 }
3232 
3233 static bool
isInstantiationOf(ClassTemplatePartialSpecializationDecl * Pattern,ClassTemplatePartialSpecializationDecl * Instance)3234 isInstantiationOf(ClassTemplatePartialSpecializationDecl *Pattern,
3235                   ClassTemplatePartialSpecializationDecl *Instance) {
3236   Pattern
3237     = cast<ClassTemplatePartialSpecializationDecl>(Pattern->getCanonicalDecl());
3238   do {
3239     Instance = cast<ClassTemplatePartialSpecializationDecl>(
3240                                                 Instance->getCanonicalDecl());
3241     if (Pattern == Instance)
3242       return true;
3243     Instance = Instance->getInstantiatedFromMember();
3244   } while (Instance);
3245 
3246   return false;
3247 }
3248 
isInstantiationOf(CXXRecordDecl * Pattern,CXXRecordDecl * Instance)3249 static bool isInstantiationOf(CXXRecordDecl *Pattern,
3250                               CXXRecordDecl *Instance) {
3251   Pattern = Pattern->getCanonicalDecl();
3252 
3253   do {
3254     Instance = Instance->getCanonicalDecl();
3255     if (Pattern == Instance) return true;
3256     Instance = Instance->getInstantiatedFromMemberClass();
3257   } while (Instance);
3258 
3259   return false;
3260 }
3261 
isInstantiationOf(FunctionDecl * Pattern,FunctionDecl * Instance)3262 static bool isInstantiationOf(FunctionDecl *Pattern,
3263                               FunctionDecl *Instance) {
3264   Pattern = Pattern->getCanonicalDecl();
3265 
3266   do {
3267     Instance = Instance->getCanonicalDecl();
3268     if (Pattern == Instance) return true;
3269     Instance = Instance->getInstantiatedFromMemberFunction();
3270   } while (Instance);
3271 
3272   return false;
3273 }
3274 
isInstantiationOf(EnumDecl * Pattern,EnumDecl * Instance)3275 static bool isInstantiationOf(EnumDecl *Pattern,
3276                               EnumDecl *Instance) {
3277   Pattern = Pattern->getCanonicalDecl();
3278 
3279   do {
3280     Instance = Instance->getCanonicalDecl();
3281     if (Pattern == Instance) return true;
3282     Instance = Instance->getInstantiatedFromMemberEnum();
3283   } while (Instance);
3284 
3285   return false;
3286 }
3287 
isInstantiationOf(UsingShadowDecl * Pattern,UsingShadowDecl * Instance,ASTContext & C)3288 static bool isInstantiationOf(UsingShadowDecl *Pattern,
3289                               UsingShadowDecl *Instance,
3290                               ASTContext &C) {
3291   return C.getInstantiatedFromUsingShadowDecl(Instance) == Pattern;
3292 }
3293 
isInstantiationOf(UsingDecl * Pattern,UsingDecl * Instance,ASTContext & C)3294 static bool isInstantiationOf(UsingDecl *Pattern,
3295                               UsingDecl *Instance,
3296                               ASTContext &C) {
3297   return C.getInstantiatedFromUsingDecl(Instance) == Pattern;
3298 }
3299 
isInstantiationOf(UnresolvedUsingValueDecl * Pattern,UsingDecl * Instance,ASTContext & C)3300 static bool isInstantiationOf(UnresolvedUsingValueDecl *Pattern,
3301                               UsingDecl *Instance,
3302                               ASTContext &C) {
3303   return C.getInstantiatedFromUsingDecl(Instance) == Pattern;
3304 }
3305 
isInstantiationOf(UnresolvedUsingTypenameDecl * Pattern,UsingDecl * Instance,ASTContext & C)3306 static bool isInstantiationOf(UnresolvedUsingTypenameDecl *Pattern,
3307                               UsingDecl *Instance,
3308                               ASTContext &C) {
3309   return C.getInstantiatedFromUsingDecl(Instance) == Pattern;
3310 }
3311 
isInstantiationOfStaticDataMember(VarDecl * Pattern,VarDecl * Instance)3312 static bool isInstantiationOfStaticDataMember(VarDecl *Pattern,
3313                                               VarDecl *Instance) {
3314   assert(Instance->isStaticDataMember());
3315 
3316   Pattern = Pattern->getCanonicalDecl();
3317 
3318   do {
3319     Instance = Instance->getCanonicalDecl();
3320     if (Pattern == Instance) return true;
3321     Instance = Instance->getInstantiatedFromStaticDataMember();
3322   } while (Instance);
3323 
3324   return false;
3325 }
3326 
3327 // Other is the prospective instantiation
3328 // D is the prospective pattern
isInstantiationOf(ASTContext & Ctx,NamedDecl * D,Decl * Other)3329 static bool isInstantiationOf(ASTContext &Ctx, NamedDecl *D, Decl *Other) {
3330   if (D->getKind() != Other->getKind()) {
3331     if (UnresolvedUsingTypenameDecl *UUD
3332           = dyn_cast<UnresolvedUsingTypenameDecl>(D)) {
3333       if (UsingDecl *UD = dyn_cast<UsingDecl>(Other)) {
3334         return isInstantiationOf(UUD, UD, Ctx);
3335       }
3336     }
3337 
3338     if (UnresolvedUsingValueDecl *UUD
3339           = dyn_cast<UnresolvedUsingValueDecl>(D)) {
3340       if (UsingDecl *UD = dyn_cast<UsingDecl>(Other)) {
3341         return isInstantiationOf(UUD, UD, Ctx);
3342       }
3343     }
3344 
3345     return false;
3346   }
3347 
3348   if (CXXRecordDecl *Record = dyn_cast<CXXRecordDecl>(Other))
3349     return isInstantiationOf(cast<CXXRecordDecl>(D), Record);
3350 
3351   if (FunctionDecl *Function = dyn_cast<FunctionDecl>(Other))
3352     return isInstantiationOf(cast<FunctionDecl>(D), Function);
3353 
3354   if (EnumDecl *Enum = dyn_cast<EnumDecl>(Other))
3355     return isInstantiationOf(cast<EnumDecl>(D), Enum);
3356 
3357   if (VarDecl *Var = dyn_cast<VarDecl>(Other))
3358     if (Var->isStaticDataMember())
3359       return isInstantiationOfStaticDataMember(cast<VarDecl>(D), Var);
3360 
3361   if (ClassTemplateDecl *Temp = dyn_cast<ClassTemplateDecl>(Other))
3362     return isInstantiationOf(cast<ClassTemplateDecl>(D), Temp);
3363 
3364   if (FunctionTemplateDecl *Temp = dyn_cast<FunctionTemplateDecl>(Other))
3365     return isInstantiationOf(cast<FunctionTemplateDecl>(D), Temp);
3366 
3367   if (ClassTemplatePartialSpecializationDecl *PartialSpec
3368         = dyn_cast<ClassTemplatePartialSpecializationDecl>(Other))
3369     return isInstantiationOf(cast<ClassTemplatePartialSpecializationDecl>(D),
3370                              PartialSpec);
3371 
3372   if (FieldDecl *Field = dyn_cast<FieldDecl>(Other)) {
3373     if (!Field->getDeclName()) {
3374       // This is an unnamed field.
3375       return Ctx.getInstantiatedFromUnnamedFieldDecl(Field) ==
3376         cast<FieldDecl>(D);
3377     }
3378   }
3379 
3380   if (UsingDecl *Using = dyn_cast<UsingDecl>(Other))
3381     return isInstantiationOf(cast<UsingDecl>(D), Using, Ctx);
3382 
3383   if (UsingShadowDecl *Shadow = dyn_cast<UsingShadowDecl>(Other))
3384     return isInstantiationOf(cast<UsingShadowDecl>(D), Shadow, Ctx);
3385 
3386   return D->getDeclName() && isa<NamedDecl>(Other) &&
3387     D->getDeclName() == cast<NamedDecl>(Other)->getDeclName();
3388 }
3389 
3390 template<typename ForwardIterator>
findInstantiationOf(ASTContext & Ctx,NamedDecl * D,ForwardIterator first,ForwardIterator last)3391 static NamedDecl *findInstantiationOf(ASTContext &Ctx,
3392                                       NamedDecl *D,
3393                                       ForwardIterator first,
3394                                       ForwardIterator last) {
3395   for (; first != last; ++first)
3396     if (isInstantiationOf(Ctx, D, *first))
3397       return cast<NamedDecl>(*first);
3398 
3399   return 0;
3400 }
3401 
3402 /// \brief Finds the instantiation of the given declaration context
3403 /// within the current instantiation.
3404 ///
3405 /// \returns NULL if there was an error
FindInstantiatedContext(SourceLocation Loc,DeclContext * DC,const MultiLevelTemplateArgumentList & TemplateArgs)3406 DeclContext *Sema::FindInstantiatedContext(SourceLocation Loc, DeclContext* DC,
3407                           const MultiLevelTemplateArgumentList &TemplateArgs) {
3408   if (NamedDecl *D = dyn_cast<NamedDecl>(DC)) {
3409     Decl* ID = FindInstantiatedDecl(Loc, D, TemplateArgs);
3410     return cast_or_null<DeclContext>(ID);
3411   } else return DC;
3412 }
3413 
3414 /// \brief Find the instantiation of the given declaration within the
3415 /// current instantiation.
3416 ///
3417 /// This routine is intended to be used when \p D is a declaration
3418 /// referenced from within a template, that needs to mapped into the
3419 /// corresponding declaration within an instantiation. For example,
3420 /// given:
3421 ///
3422 /// \code
3423 /// template<typename T>
3424 /// struct X {
3425 ///   enum Kind {
3426 ///     KnownValue = sizeof(T)
3427 ///   };
3428 ///
3429 ///   bool getKind() const { return KnownValue; }
3430 /// };
3431 ///
3432 /// template struct X<int>;
3433 /// \endcode
3434 ///
3435 /// In the instantiation of X<int>::getKind(), we need to map the
3436 /// EnumConstantDecl for KnownValue (which refers to
3437 /// X<T>::\<Kind>\::KnownValue) to its instantiation
3438 /// (X<int>::\<Kind>\::KnownValue). InstantiateCurrentDeclRef() performs
3439 /// this mapping from within the instantiation of X<int>.
FindInstantiatedDecl(SourceLocation Loc,NamedDecl * D,const MultiLevelTemplateArgumentList & TemplateArgs)3440 NamedDecl *Sema::FindInstantiatedDecl(SourceLocation Loc, NamedDecl *D,
3441                           const MultiLevelTemplateArgumentList &TemplateArgs) {
3442   DeclContext *ParentDC = D->getDeclContext();
3443   if (isa<ParmVarDecl>(D) || isa<NonTypeTemplateParmDecl>(D) ||
3444       isa<TemplateTypeParmDecl>(D) || isa<TemplateTemplateParmDecl>(D) ||
3445       (ParentDC->isFunctionOrMethod() && ParentDC->isDependentContext()) ||
3446       (isa<CXXRecordDecl>(D) && cast<CXXRecordDecl>(D)->isLambda())) {
3447     // D is a local of some kind. Look into the map of local
3448     // declarations to their instantiations.
3449     typedef LocalInstantiationScope::DeclArgumentPack DeclArgumentPack;
3450     llvm::PointerUnion<Decl *, DeclArgumentPack *> *Found
3451       = CurrentInstantiationScope->findInstantiationOf(D);
3452 
3453     if (Found) {
3454       if (Decl *FD = Found->dyn_cast<Decl *>())
3455         return cast<NamedDecl>(FD);
3456 
3457       int PackIdx = ArgumentPackSubstitutionIndex;
3458       assert(PackIdx != -1 && "found declaration pack but not pack expanding");
3459       return cast<NamedDecl>((*Found->get<DeclArgumentPack *>())[PackIdx]);
3460     }
3461 
3462     // If we didn't find the decl, then we must have a label decl that hasn't
3463     // been found yet.  Lazily instantiate it and return it now.
3464     assert(isa<LabelDecl>(D));
3465 
3466     Decl *Inst = SubstDecl(D, CurContext, TemplateArgs);
3467     assert(Inst && "Failed to instantiate label??");
3468 
3469     CurrentInstantiationScope->InstantiatedLocal(D, Inst);
3470     return cast<LabelDecl>(Inst);
3471   }
3472 
3473   if (CXXRecordDecl *Record = dyn_cast<CXXRecordDecl>(D)) {
3474     if (!Record->isDependentContext())
3475       return D;
3476 
3477     // Determine whether this record is the "templated" declaration describing
3478     // a class template or class template partial specialization.
3479     ClassTemplateDecl *ClassTemplate = Record->getDescribedClassTemplate();
3480     if (ClassTemplate)
3481       ClassTemplate = ClassTemplate->getCanonicalDecl();
3482     else if (ClassTemplatePartialSpecializationDecl *PartialSpec
3483                = dyn_cast<ClassTemplatePartialSpecializationDecl>(Record))
3484       ClassTemplate = PartialSpec->getSpecializedTemplate()->getCanonicalDecl();
3485 
3486     // Walk the current context to find either the record or an instantiation of
3487     // it.
3488     DeclContext *DC = CurContext;
3489     while (!DC->isFileContext()) {
3490       // If we're performing substitution while we're inside the template
3491       // definition, we'll find our own context. We're done.
3492       if (DC->Equals(Record))
3493         return Record;
3494 
3495       if (CXXRecordDecl *InstRecord = dyn_cast<CXXRecordDecl>(DC)) {
3496         // Check whether we're in the process of instantiating a class template
3497         // specialization of the template we're mapping.
3498         if (ClassTemplateSpecializationDecl *InstSpec
3499                       = dyn_cast<ClassTemplateSpecializationDecl>(InstRecord)){
3500           ClassTemplateDecl *SpecTemplate = InstSpec->getSpecializedTemplate();
3501           if (ClassTemplate && isInstantiationOf(ClassTemplate, SpecTemplate))
3502             return InstRecord;
3503         }
3504 
3505         // Check whether we're in the process of instantiating a member class.
3506         if (isInstantiationOf(Record, InstRecord))
3507           return InstRecord;
3508       }
3509 
3510 
3511       // Move to the outer template scope.
3512       if (FunctionDecl *FD = dyn_cast<FunctionDecl>(DC)) {
3513         if (FD->getFriendObjectKind() && FD->getDeclContext()->isFileContext()){
3514           DC = FD->getLexicalDeclContext();
3515           continue;
3516         }
3517       }
3518 
3519       DC = DC->getParent();
3520     }
3521 
3522     // Fall through to deal with other dependent record types (e.g.,
3523     // anonymous unions in class templates).
3524   }
3525 
3526   if (!ParentDC->isDependentContext())
3527     return D;
3528 
3529   ParentDC = FindInstantiatedContext(Loc, ParentDC, TemplateArgs);
3530   if (!ParentDC)
3531     return 0;
3532 
3533   if (ParentDC != D->getDeclContext()) {
3534     // We performed some kind of instantiation in the parent context,
3535     // so now we need to look into the instantiated parent context to
3536     // find the instantiation of the declaration D.
3537 
3538     // If our context used to be dependent, we may need to instantiate
3539     // it before performing lookup into that context.
3540     bool IsBeingInstantiated = false;
3541     if (CXXRecordDecl *Spec = dyn_cast<CXXRecordDecl>(ParentDC)) {
3542       if (!Spec->isDependentContext()) {
3543         QualType T = Context.getTypeDeclType(Spec);
3544         const RecordType *Tag = T->getAs<RecordType>();
3545         assert(Tag && "type of non-dependent record is not a RecordType");
3546         if (Tag->isBeingDefined())
3547           IsBeingInstantiated = true;
3548         if (!Tag->isBeingDefined() &&
3549             RequireCompleteType(Loc, T, diag::err_incomplete_type))
3550           return 0;
3551 
3552         ParentDC = Tag->getDecl();
3553       }
3554     }
3555 
3556     NamedDecl *Result = 0;
3557     if (D->getDeclName()) {
3558       DeclContext::lookup_result Found = ParentDC->lookup(D->getDeclName());
3559       Result = findInstantiationOf(Context, D, Found.begin(), Found.end());
3560     } else {
3561       // Since we don't have a name for the entity we're looking for,
3562       // our only option is to walk through all of the declarations to
3563       // find that name. This will occur in a few cases:
3564       //
3565       //   - anonymous struct/union within a template
3566       //   - unnamed class/struct/union/enum within a template
3567       //
3568       // FIXME: Find a better way to find these instantiations!
3569       Result = findInstantiationOf(Context, D,
3570                                    ParentDC->decls_begin(),
3571                                    ParentDC->decls_end());
3572     }
3573 
3574     if (!Result) {
3575       if (isa<UsingShadowDecl>(D)) {
3576         // UsingShadowDecls can instantiate to nothing because of using hiding.
3577       } else if (Diags.hasErrorOccurred()) {
3578         // We've already complained about something, so most likely this
3579         // declaration failed to instantiate. There's no point in complaining
3580         // further, since this is normal in invalid code.
3581       } else if (IsBeingInstantiated) {
3582         // The class in which this member exists is currently being
3583         // instantiated, and we haven't gotten around to instantiating this
3584         // member yet. This can happen when the code uses forward declarations
3585         // of member classes, and introduces ordering dependencies via
3586         // template instantiation.
3587         Diag(Loc, diag::err_member_not_yet_instantiated)
3588           << D->getDeclName()
3589           << Context.getTypeDeclType(cast<CXXRecordDecl>(ParentDC));
3590         Diag(D->getLocation(), diag::note_non_instantiated_member_here);
3591       } else if (EnumConstantDecl *ED = dyn_cast<EnumConstantDecl>(D)) {
3592         // This enumeration constant was found when the template was defined,
3593         // but can't be found in the instantiation. This can happen if an
3594         // unscoped enumeration member is explicitly specialized.
3595         EnumDecl *Enum = cast<EnumDecl>(ED->getLexicalDeclContext());
3596         EnumDecl *Spec = cast<EnumDecl>(FindInstantiatedDecl(Loc, Enum,
3597                                                              TemplateArgs));
3598         assert(Spec->getTemplateSpecializationKind() ==
3599                  TSK_ExplicitSpecialization);
3600         Diag(Loc, diag::err_enumerator_does_not_exist)
3601           << D->getDeclName()
3602           << Context.getTypeDeclType(cast<TypeDecl>(Spec->getDeclContext()));
3603         Diag(Spec->getLocation(), diag::note_enum_specialized_here)
3604           << Context.getTypeDeclType(Spec);
3605       } else {
3606         // We should have found something, but didn't.
3607         llvm_unreachable("Unable to find instantiation of declaration!");
3608       }
3609     }
3610 
3611     D = Result;
3612   }
3613 
3614   return D;
3615 }
3616 
3617 /// \brief Performs template instantiation for all implicit template
3618 /// instantiations we have seen until this point.
PerformPendingInstantiations(bool LocalOnly)3619 void Sema::PerformPendingInstantiations(bool LocalOnly) {
3620   // Load pending instantiations from the external source.
3621   if (!LocalOnly && ExternalSource) {
3622     SmallVector<PendingImplicitInstantiation, 4> Pending;
3623     ExternalSource->ReadPendingInstantiations(Pending);
3624     PendingInstantiations.insert(PendingInstantiations.begin(),
3625                                  Pending.begin(), Pending.end());
3626   }
3627 
3628   while (!PendingLocalImplicitInstantiations.empty() ||
3629          (!LocalOnly && !PendingInstantiations.empty())) {
3630     PendingImplicitInstantiation Inst;
3631 
3632     if (PendingLocalImplicitInstantiations.empty()) {
3633       Inst = PendingInstantiations.front();
3634       PendingInstantiations.pop_front();
3635     } else {
3636       Inst = PendingLocalImplicitInstantiations.front();
3637       PendingLocalImplicitInstantiations.pop_front();
3638     }
3639 
3640     // Instantiate function definitions
3641     if (FunctionDecl *Function = dyn_cast<FunctionDecl>(Inst.first)) {
3642       PrettyDeclStackTraceEntry CrashInfo(*this, Function, SourceLocation(),
3643                                           "instantiating function definition");
3644       bool DefinitionRequired = Function->getTemplateSpecializationKind() ==
3645                                 TSK_ExplicitInstantiationDefinition;
3646       InstantiateFunctionDefinition(/*FIXME:*/Inst.second, Function, true,
3647                                     DefinitionRequired);
3648       continue;
3649     }
3650 
3651     // Instantiate static data member definitions.
3652     VarDecl *Var = cast<VarDecl>(Inst.first);
3653     assert(Var->isStaticDataMember() && "Not a static data member?");
3654 
3655     // Don't try to instantiate declarations if the most recent redeclaration
3656     // is invalid.
3657     if (Var->getMostRecentDecl()->isInvalidDecl())
3658       continue;
3659 
3660     // Check if the most recent declaration has changed the specialization kind
3661     // and removed the need for implicit instantiation.
3662     switch (Var->getMostRecentDecl()->getTemplateSpecializationKind()) {
3663     case TSK_Undeclared:
3664       llvm_unreachable("Cannot instantitiate an undeclared specialization.");
3665     case TSK_ExplicitInstantiationDeclaration:
3666     case TSK_ExplicitSpecialization:
3667       continue;  // No longer need to instantiate this type.
3668     case TSK_ExplicitInstantiationDefinition:
3669       // We only need an instantiation if the pending instantiation *is* the
3670       // explicit instantiation.
3671       if (Var != Var->getMostRecentDecl()) continue;
3672     case TSK_ImplicitInstantiation:
3673       break;
3674     }
3675 
3676     PrettyDeclStackTraceEntry CrashInfo(*this, Var, Var->getLocation(),
3677                                         "instantiating static data member "
3678                                         "definition");
3679 
3680     bool DefinitionRequired = Var->getTemplateSpecializationKind() ==
3681                               TSK_ExplicitInstantiationDefinition;
3682     InstantiateStaticDataMemberDefinition(/*FIXME:*/Inst.second, Var, true,
3683                                           DefinitionRequired);
3684   }
3685 }
3686 
PerformDependentDiagnostics(const DeclContext * Pattern,const MultiLevelTemplateArgumentList & TemplateArgs)3687 void Sema::PerformDependentDiagnostics(const DeclContext *Pattern,
3688                        const MultiLevelTemplateArgumentList &TemplateArgs) {
3689   for (DeclContext::ddiag_iterator I = Pattern->ddiag_begin(),
3690          E = Pattern->ddiag_end(); I != E; ++I) {
3691     DependentDiagnostic *DD = *I;
3692 
3693     switch (DD->getKind()) {
3694     case DependentDiagnostic::Access:
3695       HandleDependentAccessCheck(*DD, TemplateArgs);
3696       break;
3697     }
3698   }
3699 }
3700