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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/Sema/Lookup.h"
14 #include "clang/Sema/PrettyDeclStackTrace.h"
15 #include "clang/Sema/Template.h"
16 #include "clang/AST/ASTConsumer.h"
17 #include "clang/AST/ASTContext.h"
18 #include "clang/AST/DeclTemplate.h"
19 #include "clang/AST/DeclVisitor.h"
20 #include "clang/AST/DependentDiagnostic.h"
21 #include "clang/AST/Expr.h"
22 #include "clang/AST/ExprCXX.h"
23 #include "clang/AST/TypeLoc.h"
24 #include "clang/Lex/Preprocessor.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 
InstantiateAttrs(const MultiLevelTemplateArgumentList & TemplateArgs,const Decl * Tmpl,Decl * New,LateInstantiatedAttrVec * LateAttrs,LocalInstantiationScope * OuterMostScope)63 void Sema::InstantiateAttrs(const MultiLevelTemplateArgumentList &TemplateArgs,
64                             const Decl *Tmpl, Decl *New,
65                             LateInstantiatedAttrVec *LateAttrs,
66                             LocalInstantiationScope *OuterMostScope) {
67   for (AttrVec::const_iterator i = Tmpl->attr_begin(), e = Tmpl->attr_end();
68        i != e; ++i) {
69     const Attr *TmplAttr = *i;
70 
71     // FIXME: This should be generalized to more than just the AlignedAttr.
72     if (const AlignedAttr *Aligned = dyn_cast<AlignedAttr>(TmplAttr)) {
73       if (Aligned->isAlignmentDependent()) {
74         if (Aligned->isAlignmentExpr()) {
75           // The alignment expression is a constant expression.
76           EnterExpressionEvaluationContext Unevaluated(*this,
77                                                        Sema::ConstantEvaluated);
78 
79           ExprResult Result = SubstExpr(Aligned->getAlignmentExpr(),
80                                         TemplateArgs);
81           if (!Result.isInvalid())
82             AddAlignedAttr(Aligned->getLocation(), New, Result.takeAs<Expr>(),
83                            Aligned->getIsMSDeclSpec());
84         } else {
85           TypeSourceInfo *Result = SubstType(Aligned->getAlignmentType(),
86                                              TemplateArgs,
87                                              Aligned->getLocation(),
88                                              DeclarationName());
89           if (Result)
90             AddAlignedAttr(Aligned->getLocation(), New, Result,
91                            Aligned->getIsMSDeclSpec());
92         }
93         continue;
94       }
95     }
96 
97     if (TmplAttr->isLateParsed() && LateAttrs) {
98       // Late parsed attributes must be instantiated and attached after the
99       // enclosing class has been instantiated.  See Sema::InstantiateClass.
100       LocalInstantiationScope *Saved = 0;
101       if (CurrentInstantiationScope)
102         Saved = CurrentInstantiationScope->cloneScopes(OuterMostScope);
103       LateAttrs->push_back(LateInstantiatedAttribute(TmplAttr, Saved, New));
104     } else {
105       Attr *NewAttr = sema::instantiateTemplateAttribute(TmplAttr, Context,
106                                                          *this, TemplateArgs);
107       if (NewAttr)
108         New->addAttr(NewAttr);
109     }
110   }
111 }
112 
113 Decl *
VisitTranslationUnitDecl(TranslationUnitDecl * D)114 TemplateDeclInstantiator::VisitTranslationUnitDecl(TranslationUnitDecl *D) {
115   llvm_unreachable("Translation units cannot be instantiated");
116 }
117 
118 Decl *
VisitLabelDecl(LabelDecl * D)119 TemplateDeclInstantiator::VisitLabelDecl(LabelDecl *D) {
120   LabelDecl *Inst = LabelDecl::Create(SemaRef.Context, Owner, D->getLocation(),
121                                       D->getIdentifier());
122   Owner->addDecl(Inst);
123   return Inst;
124 }
125 
126 Decl *
VisitNamespaceDecl(NamespaceDecl * D)127 TemplateDeclInstantiator::VisitNamespaceDecl(NamespaceDecl *D) {
128   llvm_unreachable("Namespaces cannot be instantiated");
129 }
130 
131 Decl *
VisitNamespaceAliasDecl(NamespaceAliasDecl * D)132 TemplateDeclInstantiator::VisitNamespaceAliasDecl(NamespaceAliasDecl *D) {
133   NamespaceAliasDecl *Inst
134     = NamespaceAliasDecl::Create(SemaRef.Context, Owner,
135                                  D->getNamespaceLoc(),
136                                  D->getAliasLoc(),
137                                  D->getIdentifier(),
138                                  D->getQualifierLoc(),
139                                  D->getTargetNameLoc(),
140                                  D->getNamespace());
141   Owner->addDecl(Inst);
142   return Inst;
143 }
144 
InstantiateTypedefNameDecl(TypedefNameDecl * D,bool IsTypeAlias)145 Decl *TemplateDeclInstantiator::InstantiateTypedefNameDecl(TypedefNameDecl *D,
146                                                            bool IsTypeAlias) {
147   bool Invalid = false;
148   TypeSourceInfo *DI = D->getTypeSourceInfo();
149   if (DI->getType()->isInstantiationDependentType() ||
150       DI->getType()->isVariablyModifiedType()) {
151     DI = SemaRef.SubstType(DI, TemplateArgs,
152                            D->getLocation(), D->getDeclName());
153     if (!DI) {
154       Invalid = true;
155       DI = SemaRef.Context.getTrivialTypeSourceInfo(SemaRef.Context.IntTy);
156     }
157   } else {
158     SemaRef.MarkDeclarationsReferencedInType(D->getLocation(), DI->getType());
159   }
160 
161   // Create the new typedef
162   TypedefNameDecl *Typedef;
163   if (IsTypeAlias)
164     Typedef = TypeAliasDecl::Create(SemaRef.Context, Owner, D->getLocStart(),
165                                     D->getLocation(), D->getIdentifier(), DI);
166   else
167     Typedef = TypedefDecl::Create(SemaRef.Context, Owner, D->getLocStart(),
168                                   D->getLocation(), D->getIdentifier(), DI);
169   if (Invalid)
170     Typedef->setInvalidDecl();
171 
172   // If the old typedef was the name for linkage purposes of an anonymous
173   // tag decl, re-establish that relationship for the new typedef.
174   if (const TagType *oldTagType = D->getUnderlyingType()->getAs<TagType>()) {
175     TagDecl *oldTag = oldTagType->getDecl();
176     if (oldTag->getTypedefNameForAnonDecl() == D) {
177       TagDecl *newTag = DI->getType()->castAs<TagType>()->getDecl();
178       assert(!newTag->getIdentifier() && !newTag->getTypedefNameForAnonDecl());
179       newTag->setTypedefNameForAnonDecl(Typedef);
180     }
181   }
182 
183   if (TypedefNameDecl *Prev = D->getPreviousDecl()) {
184     NamedDecl *InstPrev = SemaRef.FindInstantiatedDecl(D->getLocation(), Prev,
185                                                        TemplateArgs);
186     if (!InstPrev)
187       return 0;
188 
189     TypedefNameDecl *InstPrevTypedef = cast<TypedefNameDecl>(InstPrev);
190 
191     // If the typedef types are not identical, reject them.
192     SemaRef.isIncompatibleTypedef(InstPrevTypedef, Typedef);
193 
194     Typedef->setPreviousDeclaration(InstPrevTypedef);
195   }
196 
197   SemaRef.InstantiateAttrs(TemplateArgs, D, Typedef);
198 
199   Typedef->setAccess(D->getAccess());
200 
201   return Typedef;
202 }
203 
VisitTypedefDecl(TypedefDecl * D)204 Decl *TemplateDeclInstantiator::VisitTypedefDecl(TypedefDecl *D) {
205   Decl *Typedef = InstantiateTypedefNameDecl(D, /*IsTypeAlias=*/false);
206   Owner->addDecl(Typedef);
207   return Typedef;
208 }
209 
VisitTypeAliasDecl(TypeAliasDecl * D)210 Decl *TemplateDeclInstantiator::VisitTypeAliasDecl(TypeAliasDecl *D) {
211   Decl *Typedef = InstantiateTypedefNameDecl(D, /*IsTypeAlias=*/true);
212   Owner->addDecl(Typedef);
213   return Typedef;
214 }
215 
216 Decl *
VisitTypeAliasTemplateDecl(TypeAliasTemplateDecl * D)217 TemplateDeclInstantiator::VisitTypeAliasTemplateDecl(TypeAliasTemplateDecl *D) {
218   // Create a local instantiation scope for this type alias template, which
219   // will contain the instantiations of the template parameters.
220   LocalInstantiationScope Scope(SemaRef);
221 
222   TemplateParameterList *TempParams = D->getTemplateParameters();
223   TemplateParameterList *InstParams = SubstTemplateParams(TempParams);
224   if (!InstParams)
225     return 0;
226 
227   TypeAliasDecl *Pattern = D->getTemplatedDecl();
228 
229   TypeAliasTemplateDecl *PrevAliasTemplate = 0;
230   if (Pattern->getPreviousDecl()) {
231     DeclContext::lookup_result Found = Owner->lookup(Pattern->getDeclName());
232     if (Found.first != Found.second) {
233       PrevAliasTemplate = dyn_cast<TypeAliasTemplateDecl>(*Found.first);
234     }
235   }
236 
237   TypeAliasDecl *AliasInst = cast_or_null<TypeAliasDecl>(
238     InstantiateTypedefNameDecl(Pattern, /*IsTypeAlias=*/true));
239   if (!AliasInst)
240     return 0;
241 
242   TypeAliasTemplateDecl *Inst
243     = TypeAliasTemplateDecl::Create(SemaRef.Context, Owner, D->getLocation(),
244                                     D->getDeclName(), InstParams, AliasInst);
245   if (PrevAliasTemplate)
246     Inst->setPreviousDeclaration(PrevAliasTemplate);
247 
248   Inst->setAccess(D->getAccess());
249 
250   if (!PrevAliasTemplate)
251     Inst->setInstantiatedFromMemberTemplate(D);
252 
253   Owner->addDecl(Inst);
254 
255   return Inst;
256 }
257 
VisitVarDecl(VarDecl * D)258 Decl *TemplateDeclInstantiator::VisitVarDecl(VarDecl *D) {
259   // If this is the variable for an anonymous struct or union,
260   // instantiate the anonymous struct/union type first.
261   if (const RecordType *RecordTy = D->getType()->getAs<RecordType>())
262     if (RecordTy->getDecl()->isAnonymousStructOrUnion())
263       if (!VisitCXXRecordDecl(cast<CXXRecordDecl>(RecordTy->getDecl())))
264         return 0;
265 
266   // Do substitution on the type of the declaration
267   TypeSourceInfo *DI = SemaRef.SubstType(D->getTypeSourceInfo(),
268                                          TemplateArgs,
269                                          D->getTypeSpecStartLoc(),
270                                          D->getDeclName());
271   if (!DI)
272     return 0;
273 
274   if (DI->getType()->isFunctionType()) {
275     SemaRef.Diag(D->getLocation(), diag::err_variable_instantiates_to_function)
276       << D->isStaticDataMember() << DI->getType();
277     return 0;
278   }
279 
280   // Build the instantiated declaration
281   VarDecl *Var = VarDecl::Create(SemaRef.Context, Owner,
282                                  D->getInnerLocStart(),
283                                  D->getLocation(), D->getIdentifier(),
284                                  DI->getType(), DI,
285                                  D->getStorageClass(),
286                                  D->getStorageClassAsWritten());
287   Var->setThreadSpecified(D->isThreadSpecified());
288   Var->setInitStyle(D->getInitStyle());
289   Var->setCXXForRangeDecl(D->isCXXForRangeDecl());
290   Var->setConstexpr(D->isConstexpr());
291 
292   // Substitute the nested name specifier, if any.
293   if (SubstQualifier(D, Var))
294     return 0;
295 
296   // If we are instantiating a static data member defined
297   // out-of-line, the instantiation will have the same lexical
298   // context (which will be a namespace scope) as the template.
299   if (D->isOutOfLine())
300     Var->setLexicalDeclContext(D->getLexicalDeclContext());
301 
302   Var->setAccess(D->getAccess());
303 
304   if (!D->isStaticDataMember()) {
305     Var->setUsed(D->isUsed(false));
306     Var->setReferenced(D->isReferenced());
307   }
308 
309   // FIXME: In theory, we could have a previous declaration for variables that
310   // are not static data members.
311   // FIXME: having to fake up a LookupResult is dumb.
312   LookupResult Previous(SemaRef, Var->getDeclName(), Var->getLocation(),
313                         Sema::LookupOrdinaryName, Sema::ForRedeclaration);
314   if (D->isStaticDataMember())
315     SemaRef.LookupQualifiedName(Previous, Owner, false);
316 
317   // In ARC, infer 'retaining' for variables of retainable type.
318   if (SemaRef.getLangOpts().ObjCAutoRefCount &&
319       SemaRef.inferObjCARCLifetime(Var))
320     Var->setInvalidDecl();
321 
322   SemaRef.CheckVariableDeclaration(Var, Previous);
323 
324   if (D->isOutOfLine()) {
325     D->getLexicalDeclContext()->addDecl(Var);
326     Owner->makeDeclVisibleInContext(Var);
327   } else {
328     Owner->addDecl(Var);
329     if (Owner->isFunctionOrMethod())
330       SemaRef.CurrentInstantiationScope->InstantiatedLocal(D, Var);
331   }
332   SemaRef.InstantiateAttrs(TemplateArgs, D, Var, LateAttrs, StartingScope);
333 
334   // Link instantiations of static data members back to the template from
335   // which they were instantiated.
336   if (Var->isStaticDataMember())
337     SemaRef.Context.setInstantiatedFromStaticDataMember(Var, D,
338                                                      TSK_ImplicitInstantiation);
339 
340   if (Var->getAnyInitializer()) {
341     // We already have an initializer in the class.
342   } else if (D->getInit()) {
343     if (Var->isStaticDataMember() && !D->isOutOfLine())
344       SemaRef.PushExpressionEvaluationContext(Sema::ConstantEvaluated, D);
345     else
346       SemaRef.PushExpressionEvaluationContext(Sema::PotentiallyEvaluated, D);
347 
348     // Instantiate the initializer.
349     ExprResult Init = SemaRef.SubstInitializer(D->getInit(), TemplateArgs,
350                                         D->getInitStyle() == VarDecl::CallInit);
351     if (!Init.isInvalid()) {
352       bool TypeMayContainAuto = true;
353       if (Init.get()) {
354         bool DirectInit = D->isDirectInit();
355         SemaRef.AddInitializerToDecl(Var, Init.take(), DirectInit,
356                                      TypeMayContainAuto);
357       } else
358         SemaRef.ActOnUninitializedDecl(Var, TypeMayContainAuto);
359     } else {
360       // FIXME: Not too happy about invalidating the declaration
361       // because of a bogus initializer.
362       Var->setInvalidDecl();
363     }
364 
365     SemaRef.PopExpressionEvaluationContext();
366   } else if ((!Var->isStaticDataMember() || Var->isOutOfLine()) &&
367              !Var->isCXXForRangeDecl())
368     SemaRef.ActOnUninitializedDecl(Var, false);
369 
370   // Diagnose unused local variables with dependent types, where the diagnostic
371   // will have been deferred.
372   if (!Var->isInvalidDecl() && Owner->isFunctionOrMethod() && !Var->isUsed() &&
373       D->getType()->isDependentType())
374     SemaRef.DiagnoseUnusedDecl(Var);
375 
376   return Var;
377 }
378 
VisitAccessSpecDecl(AccessSpecDecl * D)379 Decl *TemplateDeclInstantiator::VisitAccessSpecDecl(AccessSpecDecl *D) {
380   AccessSpecDecl* AD
381     = AccessSpecDecl::Create(SemaRef.Context, D->getAccess(), Owner,
382                              D->getAccessSpecifierLoc(), D->getColonLoc());
383   Owner->addHiddenDecl(AD);
384   return AD;
385 }
386 
VisitFieldDecl(FieldDecl * D)387 Decl *TemplateDeclInstantiator::VisitFieldDecl(FieldDecl *D) {
388   bool Invalid = false;
389   TypeSourceInfo *DI = D->getTypeSourceInfo();
390   if (DI->getType()->isInstantiationDependentType() ||
391       DI->getType()->isVariablyModifiedType())  {
392     DI = SemaRef.SubstType(DI, TemplateArgs,
393                            D->getLocation(), D->getDeclName());
394     if (!DI) {
395       DI = D->getTypeSourceInfo();
396       Invalid = true;
397     } else if (DI->getType()->isFunctionType()) {
398       // C++ [temp.arg.type]p3:
399       //   If a declaration acquires a function type through a type
400       //   dependent on a template-parameter and this causes a
401       //   declaration that does not use the syntactic form of a
402       //   function declarator to have function type, the program is
403       //   ill-formed.
404       SemaRef.Diag(D->getLocation(), diag::err_field_instantiates_to_function)
405         << DI->getType();
406       Invalid = true;
407     }
408   } else {
409     SemaRef.MarkDeclarationsReferencedInType(D->getLocation(), DI->getType());
410   }
411 
412   Expr *BitWidth = D->getBitWidth();
413   if (Invalid)
414     BitWidth = 0;
415   else if (BitWidth) {
416     // The bit-width expression is a constant expression.
417     EnterExpressionEvaluationContext Unevaluated(SemaRef,
418                                                  Sema::ConstantEvaluated);
419 
420     ExprResult InstantiatedBitWidth
421       = SemaRef.SubstExpr(BitWidth, TemplateArgs);
422     if (InstantiatedBitWidth.isInvalid()) {
423       Invalid = true;
424       BitWidth = 0;
425     } else
426       BitWidth = InstantiatedBitWidth.takeAs<Expr>();
427   }
428 
429   FieldDecl *Field = SemaRef.CheckFieldDecl(D->getDeclName(),
430                                             DI->getType(), DI,
431                                             cast<RecordDecl>(Owner),
432                                             D->getLocation(),
433                                             D->isMutable(),
434                                             BitWidth,
435                                             D->getInClassInitStyle(),
436                                             D->getInnerLocStart(),
437                                             D->getAccess(),
438                                             0);
439   if (!Field) {
440     cast<Decl>(Owner)->setInvalidDecl();
441     return 0;
442   }
443 
444   SemaRef.InstantiateAttrs(TemplateArgs, D, Field, LateAttrs, StartingScope);
445 
446   if (Invalid)
447     Field->setInvalidDecl();
448 
449   if (!Field->getDeclName()) {
450     // Keep track of where this decl came from.
451     SemaRef.Context.setInstantiatedFromUnnamedFieldDecl(Field, D);
452   }
453   if (CXXRecordDecl *Parent= dyn_cast<CXXRecordDecl>(Field->getDeclContext())) {
454     if (Parent->isAnonymousStructOrUnion() &&
455         Parent->getRedeclContext()->isFunctionOrMethod())
456       SemaRef.CurrentInstantiationScope->InstantiatedLocal(D, Field);
457   }
458 
459   Field->setImplicit(D->isImplicit());
460   Field->setAccess(D->getAccess());
461   Owner->addDecl(Field);
462 
463   return Field;
464 }
465 
VisitIndirectFieldDecl(IndirectFieldDecl * D)466 Decl *TemplateDeclInstantiator::VisitIndirectFieldDecl(IndirectFieldDecl *D) {
467   NamedDecl **NamedChain =
468     new (SemaRef.Context)NamedDecl*[D->getChainingSize()];
469 
470   int i = 0;
471   for (IndirectFieldDecl::chain_iterator PI =
472        D->chain_begin(), PE = D->chain_end();
473        PI != PE; ++PI) {
474     NamedDecl *Next = SemaRef.FindInstantiatedDecl(D->getLocation(), *PI,
475                                               TemplateArgs);
476     if (!Next)
477       return 0;
478 
479     NamedChain[i++] = Next;
480   }
481 
482   QualType T = cast<FieldDecl>(NamedChain[i-1])->getType();
483   IndirectFieldDecl* IndirectField
484     = IndirectFieldDecl::Create(SemaRef.Context, Owner, D->getLocation(),
485                                 D->getIdentifier(), T,
486                                 NamedChain, D->getChainingSize());
487 
488 
489   IndirectField->setImplicit(D->isImplicit());
490   IndirectField->setAccess(D->getAccess());
491   Owner->addDecl(IndirectField);
492   return IndirectField;
493 }
494 
VisitFriendDecl(FriendDecl * D)495 Decl *TemplateDeclInstantiator::VisitFriendDecl(FriendDecl *D) {
496   // Handle friend type expressions by simply substituting template
497   // parameters into the pattern type and checking the result.
498   if (TypeSourceInfo *Ty = D->getFriendType()) {
499     TypeSourceInfo *InstTy;
500     // If this is an unsupported friend, don't bother substituting template
501     // arguments into it. The actual type referred to won't be used by any
502     // parts of Clang, and may not be valid for instantiating. Just use the
503     // same info for the instantiated friend.
504     if (D->isUnsupportedFriend()) {
505       InstTy = Ty;
506     } else {
507       InstTy = SemaRef.SubstType(Ty, TemplateArgs,
508                                  D->getLocation(), DeclarationName());
509     }
510     if (!InstTy)
511       return 0;
512 
513     FriendDecl *FD = SemaRef.CheckFriendTypeDecl(D->getLocation(),
514                                                  D->getFriendLoc(), InstTy);
515     if (!FD)
516       return 0;
517 
518     FD->setAccess(AS_public);
519     FD->setUnsupportedFriend(D->isUnsupportedFriend());
520     Owner->addDecl(FD);
521     return FD;
522   }
523 
524   NamedDecl *ND = D->getFriendDecl();
525   assert(ND && "friend decl must be a decl or a type!");
526 
527   // All of the Visit implementations for the various potential friend
528   // declarations have to be carefully written to work for friend
529   // objects, with the most important detail being that the target
530   // decl should almost certainly not be placed in Owner.
531   Decl *NewND = Visit(ND);
532   if (!NewND) return 0;
533 
534   FriendDecl *FD =
535     FriendDecl::Create(SemaRef.Context, Owner, D->getLocation(),
536                        cast<NamedDecl>(NewND), D->getFriendLoc());
537   FD->setAccess(AS_public);
538   FD->setUnsupportedFriend(D->isUnsupportedFriend());
539   Owner->addDecl(FD);
540   return FD;
541 }
542 
VisitStaticAssertDecl(StaticAssertDecl * D)543 Decl *TemplateDeclInstantiator::VisitStaticAssertDecl(StaticAssertDecl *D) {
544   Expr *AssertExpr = D->getAssertExpr();
545 
546   // The expression in a static assertion is a constant expression.
547   EnterExpressionEvaluationContext Unevaluated(SemaRef,
548                                                Sema::ConstantEvaluated);
549 
550   ExprResult InstantiatedAssertExpr
551     = SemaRef.SubstExpr(AssertExpr, TemplateArgs);
552   if (InstantiatedAssertExpr.isInvalid())
553     return 0;
554 
555   return SemaRef.BuildStaticAssertDeclaration(D->getLocation(),
556                                               InstantiatedAssertExpr.get(),
557                                               D->getMessage(),
558                                               D->getRParenLoc(),
559                                               D->isFailed());
560 }
561 
VisitEnumDecl(EnumDecl * D)562 Decl *TemplateDeclInstantiator::VisitEnumDecl(EnumDecl *D) {
563   EnumDecl *PrevDecl = 0;
564   if (D->getPreviousDecl()) {
565     NamedDecl *Prev = SemaRef.FindInstantiatedDecl(D->getLocation(),
566                                                    D->getPreviousDecl(),
567                                                    TemplateArgs);
568     if (!Prev) return 0;
569     PrevDecl = cast<EnumDecl>(Prev);
570   }
571 
572   EnumDecl *Enum = EnumDecl::Create(SemaRef.Context, Owner, D->getLocStart(),
573                                     D->getLocation(), D->getIdentifier(),
574                                     PrevDecl, D->isScoped(),
575                                     D->isScopedUsingClassTag(), D->isFixed());
576   if (D->isFixed()) {
577     if (TypeSourceInfo *TI = D->getIntegerTypeSourceInfo()) {
578       // If we have type source information for the underlying type, it means it
579       // has been explicitly set by the user. Perform substitution on it before
580       // moving on.
581       SourceLocation UnderlyingLoc = TI->getTypeLoc().getBeginLoc();
582       TypeSourceInfo *NewTI = SemaRef.SubstType(TI, TemplateArgs, UnderlyingLoc,
583                                                 DeclarationName());
584       if (!NewTI || SemaRef.CheckEnumUnderlyingType(NewTI))
585         Enum->setIntegerType(SemaRef.Context.IntTy);
586       else
587         Enum->setIntegerTypeSourceInfo(NewTI);
588     } else {
589       assert(!D->getIntegerType()->isDependentType()
590              && "Dependent type without type source info");
591       Enum->setIntegerType(D->getIntegerType());
592     }
593   }
594 
595   SemaRef.InstantiateAttrs(TemplateArgs, D, Enum);
596 
597   Enum->setInstantiationOfMemberEnum(D, TSK_ImplicitInstantiation);
598   Enum->setAccess(D->getAccess());
599   if (SubstQualifier(D, Enum)) return 0;
600   Owner->addDecl(Enum);
601 
602   EnumDecl *Def = D->getDefinition();
603   if (Def && Def != D) {
604     // If this is an out-of-line definition of an enum member template, check
605     // that the underlying types match in the instantiation of both
606     // declarations.
607     if (TypeSourceInfo *TI = Def->getIntegerTypeSourceInfo()) {
608       SourceLocation UnderlyingLoc = TI->getTypeLoc().getBeginLoc();
609       QualType DefnUnderlying =
610         SemaRef.SubstType(TI->getType(), TemplateArgs,
611                           UnderlyingLoc, DeclarationName());
612       SemaRef.CheckEnumRedeclaration(Def->getLocation(), Def->isScoped(),
613                                      DefnUnderlying, Enum);
614     }
615   }
616 
617   if (D->getDeclContext()->isFunctionOrMethod())
618     SemaRef.CurrentInstantiationScope->InstantiatedLocal(D, Enum);
619 
620   // C++11 [temp.inst]p1: The implicit instantiation of a class template
621   // specialization causes the implicit instantiation of the declarations, but
622   // not the definitions of scoped member enumerations.
623   // FIXME: There appears to be no wording for what happens for an enum defined
624   // within a block scope, but we treat that much like a member template. Only
625   // instantiate the definition when visiting the definition in that case, since
626   // we will visit all redeclarations.
627   if (!Enum->isScoped() && Def &&
628       (!D->getDeclContext()->isFunctionOrMethod() || D->isCompleteDefinition()))
629     InstantiateEnumDefinition(Enum, Def);
630 
631   return Enum;
632 }
633 
InstantiateEnumDefinition(EnumDecl * Enum,EnumDecl * Pattern)634 void TemplateDeclInstantiator::InstantiateEnumDefinition(
635     EnumDecl *Enum, EnumDecl *Pattern) {
636   Enum->startDefinition();
637 
638   // Update the location to refer to the definition.
639   Enum->setLocation(Pattern->getLocation());
640 
641   SmallVector<Decl*, 4> Enumerators;
642 
643   EnumConstantDecl *LastEnumConst = 0;
644   for (EnumDecl::enumerator_iterator EC = Pattern->enumerator_begin(),
645          ECEnd = Pattern->enumerator_end();
646        EC != ECEnd; ++EC) {
647     // The specified value for the enumerator.
648     ExprResult Value = SemaRef.Owned((Expr *)0);
649     if (Expr *UninstValue = EC->getInitExpr()) {
650       // The enumerator's value expression is a constant expression.
651       EnterExpressionEvaluationContext Unevaluated(SemaRef,
652                                                    Sema::ConstantEvaluated);
653 
654       Value = SemaRef.SubstExpr(UninstValue, TemplateArgs);
655     }
656 
657     // Drop the initial value and continue.
658     bool isInvalid = false;
659     if (Value.isInvalid()) {
660       Value = SemaRef.Owned((Expr *)0);
661       isInvalid = true;
662     }
663 
664     EnumConstantDecl *EnumConst
665       = SemaRef.CheckEnumConstant(Enum, LastEnumConst,
666                                   EC->getLocation(), EC->getIdentifier(),
667                                   Value.get());
668 
669     if (isInvalid) {
670       if (EnumConst)
671         EnumConst->setInvalidDecl();
672       Enum->setInvalidDecl();
673     }
674 
675     if (EnumConst) {
676       SemaRef.InstantiateAttrs(TemplateArgs, *EC, EnumConst);
677 
678       EnumConst->setAccess(Enum->getAccess());
679       Enum->addDecl(EnumConst);
680       Enumerators.push_back(EnumConst);
681       LastEnumConst = EnumConst;
682 
683       if (Pattern->getDeclContext()->isFunctionOrMethod() &&
684           !Enum->isScoped()) {
685         // If the enumeration is within a function or method, record the enum
686         // constant as a local.
687         SemaRef.CurrentInstantiationScope->InstantiatedLocal(*EC, EnumConst);
688       }
689     }
690   }
691 
692   // FIXME: Fixup LBraceLoc
693   SemaRef.ActOnEnumBody(Enum->getLocation(), SourceLocation(),
694                         Enum->getRBraceLoc(), Enum,
695                         Enumerators.data(), Enumerators.size(),
696                         0, 0);
697 }
698 
VisitEnumConstantDecl(EnumConstantDecl * D)699 Decl *TemplateDeclInstantiator::VisitEnumConstantDecl(EnumConstantDecl *D) {
700   llvm_unreachable("EnumConstantDecls can only occur within EnumDecls.");
701 }
702 
VisitClassTemplateDecl(ClassTemplateDecl * D)703 Decl *TemplateDeclInstantiator::VisitClassTemplateDecl(ClassTemplateDecl *D) {
704   bool isFriend = (D->getFriendObjectKind() != Decl::FOK_None);
705 
706   // Create a local instantiation scope for this class template, which
707   // will contain the instantiations of the template parameters.
708   LocalInstantiationScope Scope(SemaRef);
709   TemplateParameterList *TempParams = D->getTemplateParameters();
710   TemplateParameterList *InstParams = SubstTemplateParams(TempParams);
711   if (!InstParams)
712     return NULL;
713 
714   CXXRecordDecl *Pattern = D->getTemplatedDecl();
715 
716   // Instantiate the qualifier.  We have to do this first in case
717   // we're a friend declaration, because if we are then we need to put
718   // the new declaration in the appropriate context.
719   NestedNameSpecifierLoc QualifierLoc = Pattern->getQualifierLoc();
720   if (QualifierLoc) {
721     QualifierLoc = SemaRef.SubstNestedNameSpecifierLoc(QualifierLoc,
722                                                        TemplateArgs);
723     if (!QualifierLoc)
724       return 0;
725   }
726 
727   CXXRecordDecl *PrevDecl = 0;
728   ClassTemplateDecl *PrevClassTemplate = 0;
729 
730   if (!isFriend && Pattern->getPreviousDecl()) {
731     DeclContext::lookup_result Found = Owner->lookup(Pattern->getDeclName());
732     if (Found.first != Found.second) {
733       PrevClassTemplate = dyn_cast<ClassTemplateDecl>(*Found.first);
734       if (PrevClassTemplate)
735         PrevDecl = PrevClassTemplate->getTemplatedDecl();
736     }
737   }
738 
739   // If this isn't a friend, then it's a member template, in which
740   // case we just want to build the instantiation in the
741   // specialization.  If it is a friend, we want to build it in
742   // the appropriate context.
743   DeclContext *DC = Owner;
744   if (isFriend) {
745     if (QualifierLoc) {
746       CXXScopeSpec SS;
747       SS.Adopt(QualifierLoc);
748       DC = SemaRef.computeDeclContext(SS);
749       if (!DC) return 0;
750     } else {
751       DC = SemaRef.FindInstantiatedContext(Pattern->getLocation(),
752                                            Pattern->getDeclContext(),
753                                            TemplateArgs);
754     }
755 
756     // Look for a previous declaration of the template in the owning
757     // context.
758     LookupResult R(SemaRef, Pattern->getDeclName(), Pattern->getLocation(),
759                    Sema::LookupOrdinaryName, Sema::ForRedeclaration);
760     SemaRef.LookupQualifiedName(R, DC);
761 
762     if (R.isSingleResult()) {
763       PrevClassTemplate = R.getAsSingle<ClassTemplateDecl>();
764       if (PrevClassTemplate)
765         PrevDecl = PrevClassTemplate->getTemplatedDecl();
766     }
767 
768     if (!PrevClassTemplate && QualifierLoc) {
769       SemaRef.Diag(Pattern->getLocation(), diag::err_not_tag_in_scope)
770         << D->getTemplatedDecl()->getTagKind() << Pattern->getDeclName() << DC
771         << QualifierLoc.getSourceRange();
772       return 0;
773     }
774 
775     bool AdoptedPreviousTemplateParams = false;
776     if (PrevClassTemplate) {
777       bool Complain = true;
778 
779       // HACK: libstdc++ 4.2.1 contains an ill-formed friend class
780       // template for struct std::tr1::__detail::_Map_base, where the
781       // template parameters of the friend declaration don't match the
782       // template parameters of the original declaration. In this one
783       // case, we don't complain about the ill-formed friend
784       // declaration.
785       if (isFriend && Pattern->getIdentifier() &&
786           Pattern->getIdentifier()->isStr("_Map_base") &&
787           DC->isNamespace() &&
788           cast<NamespaceDecl>(DC)->getIdentifier() &&
789           cast<NamespaceDecl>(DC)->getIdentifier()->isStr("__detail")) {
790         DeclContext *DCParent = DC->getParent();
791         if (DCParent->isNamespace() &&
792             cast<NamespaceDecl>(DCParent)->getIdentifier() &&
793             cast<NamespaceDecl>(DCParent)->getIdentifier()->isStr("tr1")) {
794           DeclContext *DCParent2 = DCParent->getParent();
795           if (DCParent2->isNamespace() &&
796               cast<NamespaceDecl>(DCParent2)->getIdentifier() &&
797               cast<NamespaceDecl>(DCParent2)->getIdentifier()->isStr("std") &&
798               DCParent2->getParent()->isTranslationUnit())
799             Complain = false;
800         }
801       }
802 
803       TemplateParameterList *PrevParams
804         = PrevClassTemplate->getTemplateParameters();
805 
806       // Make sure the parameter lists match.
807       if (!SemaRef.TemplateParameterListsAreEqual(InstParams, PrevParams,
808                                                   Complain,
809                                                   Sema::TPL_TemplateMatch)) {
810         if (Complain)
811           return 0;
812 
813         AdoptedPreviousTemplateParams = true;
814         InstParams = PrevParams;
815       }
816 
817       // Do some additional validation, then merge default arguments
818       // from the existing declarations.
819       if (!AdoptedPreviousTemplateParams &&
820           SemaRef.CheckTemplateParameterList(InstParams, PrevParams,
821                                              Sema::TPC_ClassTemplate))
822         return 0;
823     }
824   }
825 
826   CXXRecordDecl *RecordInst
827     = CXXRecordDecl::Create(SemaRef.Context, Pattern->getTagKind(), DC,
828                             Pattern->getLocStart(), Pattern->getLocation(),
829                             Pattern->getIdentifier(), PrevDecl,
830                             /*DelayTypeCreation=*/true);
831 
832   if (QualifierLoc)
833     RecordInst->setQualifierInfo(QualifierLoc);
834 
835   ClassTemplateDecl *Inst
836     = ClassTemplateDecl::Create(SemaRef.Context, DC, D->getLocation(),
837                                 D->getIdentifier(), InstParams, RecordInst,
838                                 PrevClassTemplate);
839   RecordInst->setDescribedClassTemplate(Inst);
840 
841   if (isFriend) {
842     if (PrevClassTemplate)
843       Inst->setAccess(PrevClassTemplate->getAccess());
844     else
845       Inst->setAccess(D->getAccess());
846 
847     Inst->setObjectOfFriendDecl(PrevClassTemplate != 0);
848     // TODO: do we want to track the instantiation progeny of this
849     // friend target decl?
850   } else {
851     Inst->setAccess(D->getAccess());
852     if (!PrevClassTemplate)
853       Inst->setInstantiatedFromMemberTemplate(D);
854   }
855 
856   // Trigger creation of the type for the instantiation.
857   SemaRef.Context.getInjectedClassNameType(RecordInst,
858                                     Inst->getInjectedClassNameSpecialization());
859 
860   // Finish handling of friends.
861   if (isFriend) {
862     DC->makeDeclVisibleInContext(Inst);
863     Inst->setLexicalDeclContext(Owner);
864     RecordInst->setLexicalDeclContext(Owner);
865     return Inst;
866   }
867 
868   if (D->isOutOfLine()) {
869     Inst->setLexicalDeclContext(D->getLexicalDeclContext());
870     RecordInst->setLexicalDeclContext(D->getLexicalDeclContext());
871   }
872 
873   Owner->addDecl(Inst);
874 
875   if (!PrevClassTemplate) {
876     // Queue up any out-of-line partial specializations of this member
877     // class template; the client will force their instantiation once
878     // the enclosing class has been instantiated.
879     SmallVector<ClassTemplatePartialSpecializationDecl *, 4> PartialSpecs;
880     D->getPartialSpecializations(PartialSpecs);
881     for (unsigned I = 0, N = PartialSpecs.size(); I != N; ++I)
882       if (PartialSpecs[I]->isOutOfLine())
883         OutOfLinePartialSpecs.push_back(std::make_pair(Inst, PartialSpecs[I]));
884   }
885 
886   return Inst;
887 }
888 
889 Decl *
VisitClassTemplatePartialSpecializationDecl(ClassTemplatePartialSpecializationDecl * D)890 TemplateDeclInstantiator::VisitClassTemplatePartialSpecializationDecl(
891                                    ClassTemplatePartialSpecializationDecl *D) {
892   ClassTemplateDecl *ClassTemplate = D->getSpecializedTemplate();
893 
894   // Lookup the already-instantiated declaration in the instantiation
895   // of the class template and return that.
896   DeclContext::lookup_result Found
897     = Owner->lookup(ClassTemplate->getDeclName());
898   if (Found.first == Found.second)
899     return 0;
900 
901   ClassTemplateDecl *InstClassTemplate
902     = dyn_cast<ClassTemplateDecl>(*Found.first);
903   if (!InstClassTemplate)
904     return 0;
905 
906   if (ClassTemplatePartialSpecializationDecl *Result
907         = InstClassTemplate->findPartialSpecInstantiatedFromMember(D))
908     return Result;
909 
910   return InstantiateClassTemplatePartialSpecialization(InstClassTemplate, D);
911 }
912 
913 Decl *
VisitFunctionTemplateDecl(FunctionTemplateDecl * D)914 TemplateDeclInstantiator::VisitFunctionTemplateDecl(FunctionTemplateDecl *D) {
915   // Create a local instantiation scope for this function template, which
916   // will contain the instantiations of the template parameters and then get
917   // merged with the local instantiation scope for the function template
918   // itself.
919   LocalInstantiationScope Scope(SemaRef);
920 
921   TemplateParameterList *TempParams = D->getTemplateParameters();
922   TemplateParameterList *InstParams = SubstTemplateParams(TempParams);
923   if (!InstParams)
924     return NULL;
925 
926   FunctionDecl *Instantiated = 0;
927   if (CXXMethodDecl *DMethod = dyn_cast<CXXMethodDecl>(D->getTemplatedDecl()))
928     Instantiated = cast_or_null<FunctionDecl>(VisitCXXMethodDecl(DMethod,
929                                                                  InstParams));
930   else
931     Instantiated = cast_or_null<FunctionDecl>(VisitFunctionDecl(
932                                                           D->getTemplatedDecl(),
933                                                                 InstParams));
934 
935   if (!Instantiated)
936     return 0;
937 
938   // Link the instantiated function template declaration to the function
939   // template from which it was instantiated.
940   FunctionTemplateDecl *InstTemplate
941     = Instantiated->getDescribedFunctionTemplate();
942   InstTemplate->setAccess(D->getAccess());
943   assert(InstTemplate &&
944          "VisitFunctionDecl/CXXMethodDecl didn't create a template!");
945 
946   bool isFriend = (InstTemplate->getFriendObjectKind() != Decl::FOK_None);
947 
948   // Link the instantiation back to the pattern *unless* this is a
949   // non-definition friend declaration.
950   if (!InstTemplate->getInstantiatedFromMemberTemplate() &&
951       !(isFriend && !D->getTemplatedDecl()->isThisDeclarationADefinition()))
952     InstTemplate->setInstantiatedFromMemberTemplate(D);
953 
954   // Make declarations visible in the appropriate context.
955   if (!isFriend) {
956     Owner->addDecl(InstTemplate);
957   } else if (InstTemplate->getDeclContext()->isRecord() &&
958              !D->getPreviousDecl()) {
959     SemaRef.CheckFriendAccess(InstTemplate);
960   }
961 
962   return InstTemplate;
963 }
964 
VisitCXXRecordDecl(CXXRecordDecl * D)965 Decl *TemplateDeclInstantiator::VisitCXXRecordDecl(CXXRecordDecl *D) {
966   CXXRecordDecl *PrevDecl = 0;
967   if (D->isInjectedClassName())
968     PrevDecl = cast<CXXRecordDecl>(Owner);
969   else if (D->getPreviousDecl()) {
970     NamedDecl *Prev = SemaRef.FindInstantiatedDecl(D->getLocation(),
971                                                    D->getPreviousDecl(),
972                                                    TemplateArgs);
973     if (!Prev) return 0;
974     PrevDecl = cast<CXXRecordDecl>(Prev);
975   }
976 
977   CXXRecordDecl *Record
978     = CXXRecordDecl::Create(SemaRef.Context, D->getTagKind(), Owner,
979                             D->getLocStart(), D->getLocation(),
980                             D->getIdentifier(), PrevDecl);
981 
982   // Substitute the nested name specifier, if any.
983   if (SubstQualifier(D, Record))
984     return 0;
985 
986   Record->setImplicit(D->isImplicit());
987   // FIXME: Check against AS_none is an ugly hack to work around the issue that
988   // the tag decls introduced by friend class declarations don't have an access
989   // specifier. Remove once this area of the code gets sorted out.
990   if (D->getAccess() != AS_none)
991     Record->setAccess(D->getAccess());
992   if (!D->isInjectedClassName())
993     Record->setInstantiationOfMemberClass(D, TSK_ImplicitInstantiation);
994 
995   // If the original function was part of a friend declaration,
996   // inherit its namespace state.
997   if (Decl::FriendObjectKind FOK = D->getFriendObjectKind())
998     Record->setObjectOfFriendDecl(FOK == Decl::FOK_Declared);
999 
1000   // Make sure that anonymous structs and unions are recorded.
1001   if (D->isAnonymousStructOrUnion()) {
1002     Record->setAnonymousStructOrUnion(true);
1003     if (Record->getDeclContext()->getRedeclContext()->isFunctionOrMethod())
1004       SemaRef.CurrentInstantiationScope->InstantiatedLocal(D, Record);
1005   }
1006 
1007   Owner->addDecl(Record);
1008   return Record;
1009 }
1010 
1011 /// Normal class members are of more specific types and therefore
1012 /// don't make it here.  This function serves two purposes:
1013 ///   1) instantiating function templates
1014 ///   2) substituting friend declarations
1015 /// FIXME: preserve function definitions in case #2
VisitFunctionDecl(FunctionDecl * D,TemplateParameterList * TemplateParams)1016 Decl *TemplateDeclInstantiator::VisitFunctionDecl(FunctionDecl *D,
1017                                        TemplateParameterList *TemplateParams) {
1018   // Check whether there is already a function template specialization for
1019   // this declaration.
1020   FunctionTemplateDecl *FunctionTemplate = D->getDescribedFunctionTemplate();
1021   if (FunctionTemplate && !TemplateParams) {
1022     std::pair<const TemplateArgument *, unsigned> Innermost
1023       = TemplateArgs.getInnermost();
1024 
1025     void *InsertPos = 0;
1026     FunctionDecl *SpecFunc
1027       = FunctionTemplate->findSpecialization(Innermost.first, Innermost.second,
1028                                              InsertPos);
1029 
1030     // If we already have a function template specialization, return it.
1031     if (SpecFunc)
1032       return SpecFunc;
1033   }
1034 
1035   bool isFriend;
1036   if (FunctionTemplate)
1037     isFriend = (FunctionTemplate->getFriendObjectKind() != Decl::FOK_None);
1038   else
1039     isFriend = (D->getFriendObjectKind() != Decl::FOK_None);
1040 
1041   bool MergeWithParentScope = (TemplateParams != 0) ||
1042     Owner->isFunctionOrMethod() ||
1043     !(isa<Decl>(Owner) &&
1044       cast<Decl>(Owner)->isDefinedOutsideFunctionOrMethod());
1045   LocalInstantiationScope Scope(SemaRef, MergeWithParentScope);
1046 
1047   SmallVector<ParmVarDecl *, 4> Params;
1048   TypeSourceInfo *TInfo = SubstFunctionType(D, Params);
1049   if (!TInfo)
1050     return 0;
1051   QualType T = TInfo->getType();
1052 
1053   NestedNameSpecifierLoc QualifierLoc = D->getQualifierLoc();
1054   if (QualifierLoc) {
1055     QualifierLoc = SemaRef.SubstNestedNameSpecifierLoc(QualifierLoc,
1056                                                        TemplateArgs);
1057     if (!QualifierLoc)
1058       return 0;
1059   }
1060 
1061   // If we're instantiating a local function declaration, put the result
1062   // in the owner;  otherwise we need to find the instantiated context.
1063   DeclContext *DC;
1064   if (D->getDeclContext()->isFunctionOrMethod())
1065     DC = Owner;
1066   else if (isFriend && QualifierLoc) {
1067     CXXScopeSpec SS;
1068     SS.Adopt(QualifierLoc);
1069     DC = SemaRef.computeDeclContext(SS);
1070     if (!DC) return 0;
1071   } else {
1072     DC = SemaRef.FindInstantiatedContext(D->getLocation(), D->getDeclContext(),
1073                                          TemplateArgs);
1074   }
1075 
1076   FunctionDecl *Function =
1077       FunctionDecl::Create(SemaRef.Context, DC, D->getInnerLocStart(),
1078                            D->getLocation(), D->getDeclName(), T, TInfo,
1079                            D->getStorageClass(), D->getStorageClassAsWritten(),
1080                            D->isInlineSpecified(), D->hasWrittenPrototype(),
1081                            D->isConstexpr());
1082 
1083   if (QualifierLoc)
1084     Function->setQualifierInfo(QualifierLoc);
1085 
1086   DeclContext *LexicalDC = Owner;
1087   if (!isFriend && D->isOutOfLine()) {
1088     assert(D->getDeclContext()->isFileContext());
1089     LexicalDC = D->getDeclContext();
1090   }
1091 
1092   Function->setLexicalDeclContext(LexicalDC);
1093 
1094   // Attach the parameters
1095   if (isa<FunctionProtoType>(Function->getType().IgnoreParens())) {
1096     // Adopt the already-instantiated parameters into our own context.
1097     for (unsigned P = 0; P < Params.size(); ++P)
1098       if (Params[P])
1099         Params[P]->setOwningFunction(Function);
1100   } else {
1101     // Since we were instantiated via a typedef of a function type, create
1102     // new parameters.
1103     const FunctionProtoType *Proto
1104       = Function->getType()->getAs<FunctionProtoType>();
1105     assert(Proto && "No function prototype in template instantiation?");
1106     for (FunctionProtoType::arg_type_iterator AI = Proto->arg_type_begin(),
1107          AE = Proto->arg_type_end(); AI != AE; ++AI) {
1108       ParmVarDecl *Param
1109         = SemaRef.BuildParmVarDeclForTypedef(Function, Function->getLocation(),
1110                                              *AI);
1111       Param->setScopeInfo(0, Params.size());
1112       Params.push_back(Param);
1113     }
1114   }
1115   Function->setParams(Params);
1116 
1117   SourceLocation InstantiateAtPOI;
1118   if (TemplateParams) {
1119     // Our resulting instantiation is actually a function template, since we
1120     // are substituting only the outer template parameters. For example, given
1121     //
1122     //   template<typename T>
1123     //   struct X {
1124     //     template<typename U> friend void f(T, U);
1125     //   };
1126     //
1127     //   X<int> x;
1128     //
1129     // We are instantiating the friend function template "f" within X<int>,
1130     // which means substituting int for T, but leaving "f" as a friend function
1131     // template.
1132     // Build the function template itself.
1133     FunctionTemplate = FunctionTemplateDecl::Create(SemaRef.Context, DC,
1134                                                     Function->getLocation(),
1135                                                     Function->getDeclName(),
1136                                                     TemplateParams, Function);
1137     Function->setDescribedFunctionTemplate(FunctionTemplate);
1138 
1139     FunctionTemplate->setLexicalDeclContext(LexicalDC);
1140 
1141     if (isFriend && D->isThisDeclarationADefinition()) {
1142       // TODO: should we remember this connection regardless of whether
1143       // the friend declaration provided a body?
1144       FunctionTemplate->setInstantiatedFromMemberTemplate(
1145                                            D->getDescribedFunctionTemplate());
1146     }
1147   } else if (FunctionTemplate) {
1148     // Record this function template specialization.
1149     std::pair<const TemplateArgument *, unsigned> Innermost
1150       = TemplateArgs.getInnermost();
1151     Function->setFunctionTemplateSpecialization(FunctionTemplate,
1152                             TemplateArgumentList::CreateCopy(SemaRef.Context,
1153                                                              Innermost.first,
1154                                                              Innermost.second),
1155                                                 /*InsertPos=*/0);
1156   } else if (isFriend) {
1157     // Note, we need this connection even if the friend doesn't have a body.
1158     // Its body may exist but not have been attached yet due to deferred
1159     // parsing.
1160     // FIXME: It might be cleaner to set this when attaching the body to the
1161     // friend function declaration, however that would require finding all the
1162     // instantiations and modifying them.
1163     Function->setInstantiationOfMemberFunction(D, TSK_ImplicitInstantiation);
1164   }
1165 
1166   if (InitFunctionInstantiation(Function, D))
1167     Function->setInvalidDecl();
1168 
1169   bool isExplicitSpecialization = false;
1170 
1171   LookupResult Previous(SemaRef, Function->getDeclName(), SourceLocation(),
1172                         Sema::LookupOrdinaryName, Sema::ForRedeclaration);
1173 
1174   if (DependentFunctionTemplateSpecializationInfo *Info
1175         = D->getDependentSpecializationInfo()) {
1176     assert(isFriend && "non-friend has dependent specialization info?");
1177 
1178     // This needs to be set now for future sanity.
1179     Function->setObjectOfFriendDecl(/*HasPrevious*/ true);
1180 
1181     // Instantiate the explicit template arguments.
1182     TemplateArgumentListInfo ExplicitArgs(Info->getLAngleLoc(),
1183                                           Info->getRAngleLoc());
1184     if (SemaRef.Subst(Info->getTemplateArgs(), Info->getNumTemplateArgs(),
1185                       ExplicitArgs, TemplateArgs))
1186       return 0;
1187 
1188     // Map the candidate templates to their instantiations.
1189     for (unsigned I = 0, E = Info->getNumTemplates(); I != E; ++I) {
1190       Decl *Temp = SemaRef.FindInstantiatedDecl(D->getLocation(),
1191                                                 Info->getTemplate(I),
1192                                                 TemplateArgs);
1193       if (!Temp) return 0;
1194 
1195       Previous.addDecl(cast<FunctionTemplateDecl>(Temp));
1196     }
1197 
1198     if (SemaRef.CheckFunctionTemplateSpecialization(Function,
1199                                                     &ExplicitArgs,
1200                                                     Previous))
1201       Function->setInvalidDecl();
1202 
1203     isExplicitSpecialization = true;
1204 
1205   } else if (TemplateParams || !FunctionTemplate) {
1206     // Look only into the namespace where the friend would be declared to
1207     // find a previous declaration. This is the innermost enclosing namespace,
1208     // as described in ActOnFriendFunctionDecl.
1209     SemaRef.LookupQualifiedName(Previous, DC);
1210 
1211     // In C++, the previous declaration we find might be a tag type
1212     // (class or enum). In this case, the new declaration will hide the
1213     // tag type. Note that this does does not apply if we're declaring a
1214     // typedef (C++ [dcl.typedef]p4).
1215     if (Previous.isSingleTagDecl())
1216       Previous.clear();
1217   }
1218 
1219   SemaRef.CheckFunctionDeclaration(/*Scope*/ 0, Function, Previous,
1220                                    isExplicitSpecialization);
1221 
1222   NamedDecl *PrincipalDecl = (TemplateParams
1223                               ? cast<NamedDecl>(FunctionTemplate)
1224                               : Function);
1225 
1226   // If the original function was part of a friend declaration,
1227   // inherit its namespace state and add it to the owner.
1228   if (isFriend) {
1229     NamedDecl *PrevDecl;
1230     if (TemplateParams)
1231       PrevDecl = FunctionTemplate->getPreviousDecl();
1232     else
1233       PrevDecl = Function->getPreviousDecl();
1234 
1235     PrincipalDecl->setObjectOfFriendDecl(PrevDecl != 0);
1236     DC->makeDeclVisibleInContext(PrincipalDecl);
1237 
1238     bool queuedInstantiation = false;
1239 
1240     // C++98 [temp.friend]p5: When a function is defined in a friend function
1241     //   declaration in a class template, the function is defined at each
1242     //   instantiation of the class template. The function is defined even if it
1243     //   is never used.
1244     // C++11 [temp.friend]p4: When a function is defined in a friend function
1245     //   declaration in a class template, the function is instantiated when the
1246     //   function is odr-used.
1247     //
1248     // If -Wc++98-compat is enabled, we go through the motions of checking for a
1249     // redefinition, but don't instantiate the function.
1250     if ((!SemaRef.getLangOpts().CPlusPlus0x ||
1251          SemaRef.Diags.getDiagnosticLevel(
1252              diag::warn_cxx98_compat_friend_redefinition,
1253              Function->getLocation())
1254            != DiagnosticsEngine::Ignored) &&
1255         D->isThisDeclarationADefinition()) {
1256       // Check for a function body.
1257       const FunctionDecl *Definition = 0;
1258       if (Function->isDefined(Definition) &&
1259           Definition->getTemplateSpecializationKind() == TSK_Undeclared) {
1260         SemaRef.Diag(Function->getLocation(),
1261                      SemaRef.getLangOpts().CPlusPlus0x ?
1262                        diag::warn_cxx98_compat_friend_redefinition :
1263                        diag::err_redefinition) << Function->getDeclName();
1264         SemaRef.Diag(Definition->getLocation(), diag::note_previous_definition);
1265         if (!SemaRef.getLangOpts().CPlusPlus0x)
1266           Function->setInvalidDecl();
1267       }
1268       // Check for redefinitions due to other instantiations of this or
1269       // a similar friend function.
1270       else for (FunctionDecl::redecl_iterator R = Function->redecls_begin(),
1271                                            REnd = Function->redecls_end();
1272                 R != REnd; ++R) {
1273         if (*R == Function)
1274           continue;
1275         switch (R->getFriendObjectKind()) {
1276         case Decl::FOK_None:
1277           if (!SemaRef.getLangOpts().CPlusPlus0x &&
1278               !queuedInstantiation && R->isUsed(false)) {
1279             if (MemberSpecializationInfo *MSInfo
1280                 = Function->getMemberSpecializationInfo()) {
1281               if (MSInfo->getPointOfInstantiation().isInvalid()) {
1282                 SourceLocation Loc = R->getLocation(); // FIXME
1283                 MSInfo->setPointOfInstantiation(Loc);
1284                 SemaRef.PendingLocalImplicitInstantiations.push_back(
1285                                                  std::make_pair(Function, Loc));
1286                 queuedInstantiation = true;
1287               }
1288             }
1289           }
1290           break;
1291         default:
1292           if (const FunctionDecl *RPattern
1293               = R->getTemplateInstantiationPattern())
1294             if (RPattern->isDefined(RPattern)) {
1295               SemaRef.Diag(Function->getLocation(),
1296                            SemaRef.getLangOpts().CPlusPlus0x ?
1297                              diag::warn_cxx98_compat_friend_redefinition :
1298                              diag::err_redefinition)
1299                 << Function->getDeclName();
1300               SemaRef.Diag(R->getLocation(), diag::note_previous_definition);
1301               if (!SemaRef.getLangOpts().CPlusPlus0x)
1302                 Function->setInvalidDecl();
1303               break;
1304             }
1305         }
1306       }
1307     }
1308   }
1309 
1310   if (Function->isOverloadedOperator() && !DC->isRecord() &&
1311       PrincipalDecl->isInIdentifierNamespace(Decl::IDNS_Ordinary))
1312     PrincipalDecl->setNonMemberOperator();
1313 
1314   assert(!D->isDefaulted() && "only methods should be defaulted");
1315   return Function;
1316 }
1317 
1318 Decl *
VisitCXXMethodDecl(CXXMethodDecl * D,TemplateParameterList * TemplateParams,bool IsClassScopeSpecialization)1319 TemplateDeclInstantiator::VisitCXXMethodDecl(CXXMethodDecl *D,
1320                                       TemplateParameterList *TemplateParams,
1321                                       bool IsClassScopeSpecialization) {
1322   FunctionTemplateDecl *FunctionTemplate = D->getDescribedFunctionTemplate();
1323   if (FunctionTemplate && !TemplateParams) {
1324     // We are creating a function template specialization from a function
1325     // template. Check whether there is already a function template
1326     // specialization for this particular set of template arguments.
1327     std::pair<const TemplateArgument *, unsigned> Innermost
1328       = TemplateArgs.getInnermost();
1329 
1330     void *InsertPos = 0;
1331     FunctionDecl *SpecFunc
1332       = FunctionTemplate->findSpecialization(Innermost.first, Innermost.second,
1333                                              InsertPos);
1334 
1335     // If we already have a function template specialization, return it.
1336     if (SpecFunc)
1337       return SpecFunc;
1338   }
1339 
1340   bool isFriend;
1341   if (FunctionTemplate)
1342     isFriend = (FunctionTemplate->getFriendObjectKind() != Decl::FOK_None);
1343   else
1344     isFriend = (D->getFriendObjectKind() != Decl::FOK_None);
1345 
1346   bool MergeWithParentScope = (TemplateParams != 0) ||
1347     !(isa<Decl>(Owner) &&
1348       cast<Decl>(Owner)->isDefinedOutsideFunctionOrMethod());
1349   LocalInstantiationScope Scope(SemaRef, MergeWithParentScope);
1350 
1351   // Instantiate enclosing template arguments for friends.
1352   SmallVector<TemplateParameterList *, 4> TempParamLists;
1353   unsigned NumTempParamLists = 0;
1354   if (isFriend && (NumTempParamLists = D->getNumTemplateParameterLists())) {
1355     TempParamLists.set_size(NumTempParamLists);
1356     for (unsigned I = 0; I != NumTempParamLists; ++I) {
1357       TemplateParameterList *TempParams = D->getTemplateParameterList(I);
1358       TemplateParameterList *InstParams = SubstTemplateParams(TempParams);
1359       if (!InstParams)
1360         return NULL;
1361       TempParamLists[I] = InstParams;
1362     }
1363   }
1364 
1365   SmallVector<ParmVarDecl *, 4> Params;
1366   TypeSourceInfo *TInfo = SubstFunctionType(D, Params);
1367   if (!TInfo)
1368     return 0;
1369   QualType T = TInfo->getType();
1370 
1371   // \brief If the type of this function, after ignoring parentheses,
1372   // is not *directly* a function type, then we're instantiating a function
1373   // that was declared via a typedef, e.g.,
1374   //
1375   //   typedef int functype(int, int);
1376   //   functype func;
1377   //
1378   // In this case, we'll just go instantiate the ParmVarDecls that we
1379   // synthesized in the method declaration.
1380   if (!isa<FunctionProtoType>(T.IgnoreParens())) {
1381     assert(!Params.size() && "Instantiating type could not yield parameters");
1382     SmallVector<QualType, 4> ParamTypes;
1383     if (SemaRef.SubstParmTypes(D->getLocation(), D->param_begin(),
1384                                D->getNumParams(), TemplateArgs, ParamTypes,
1385                                &Params))
1386       return 0;
1387   }
1388 
1389   NestedNameSpecifierLoc QualifierLoc = D->getQualifierLoc();
1390   if (QualifierLoc) {
1391     QualifierLoc = SemaRef.SubstNestedNameSpecifierLoc(QualifierLoc,
1392                                                  TemplateArgs);
1393     if (!QualifierLoc)
1394       return 0;
1395   }
1396 
1397   DeclContext *DC = Owner;
1398   if (isFriend) {
1399     if (QualifierLoc) {
1400       CXXScopeSpec SS;
1401       SS.Adopt(QualifierLoc);
1402       DC = SemaRef.computeDeclContext(SS);
1403 
1404       if (DC && SemaRef.RequireCompleteDeclContext(SS, DC))
1405         return 0;
1406     } else {
1407       DC = SemaRef.FindInstantiatedContext(D->getLocation(),
1408                                            D->getDeclContext(),
1409                                            TemplateArgs);
1410     }
1411     if (!DC) return 0;
1412   }
1413 
1414   // Build the instantiated method declaration.
1415   CXXRecordDecl *Record = cast<CXXRecordDecl>(DC);
1416   CXXMethodDecl *Method = 0;
1417 
1418   SourceLocation StartLoc = D->getInnerLocStart();
1419   DeclarationNameInfo NameInfo
1420     = SemaRef.SubstDeclarationNameInfo(D->getNameInfo(), TemplateArgs);
1421   if (CXXConstructorDecl *Constructor = dyn_cast<CXXConstructorDecl>(D)) {
1422     Method = CXXConstructorDecl::Create(SemaRef.Context, Record,
1423                                         StartLoc, NameInfo, T, TInfo,
1424                                         Constructor->isExplicit(),
1425                                         Constructor->isInlineSpecified(),
1426                                         false, Constructor->isConstexpr());
1427   } else if (CXXDestructorDecl *Destructor = dyn_cast<CXXDestructorDecl>(D)) {
1428     Method = CXXDestructorDecl::Create(SemaRef.Context, Record,
1429                                        StartLoc, NameInfo, T, TInfo,
1430                                        Destructor->isInlineSpecified(),
1431                                        false);
1432   } else if (CXXConversionDecl *Conversion = dyn_cast<CXXConversionDecl>(D)) {
1433     Method = CXXConversionDecl::Create(SemaRef.Context, Record,
1434                                        StartLoc, NameInfo, T, TInfo,
1435                                        Conversion->isInlineSpecified(),
1436                                        Conversion->isExplicit(),
1437                                        Conversion->isConstexpr(),
1438                                        Conversion->getLocEnd());
1439   } else {
1440     Method = CXXMethodDecl::Create(SemaRef.Context, Record,
1441                                    StartLoc, NameInfo, T, TInfo,
1442                                    D->isStatic(),
1443                                    D->getStorageClassAsWritten(),
1444                                    D->isInlineSpecified(),
1445                                    D->isConstexpr(), D->getLocEnd());
1446   }
1447 
1448   if (QualifierLoc)
1449     Method->setQualifierInfo(QualifierLoc);
1450 
1451   if (TemplateParams) {
1452     // Our resulting instantiation is actually a function template, since we
1453     // are substituting only the outer template parameters. For example, given
1454     //
1455     //   template<typename T>
1456     //   struct X {
1457     //     template<typename U> void f(T, U);
1458     //   };
1459     //
1460     //   X<int> x;
1461     //
1462     // We are instantiating the member template "f" within X<int>, which means
1463     // substituting int for T, but leaving "f" as a member function template.
1464     // Build the function template itself.
1465     FunctionTemplate = FunctionTemplateDecl::Create(SemaRef.Context, Record,
1466                                                     Method->getLocation(),
1467                                                     Method->getDeclName(),
1468                                                     TemplateParams, Method);
1469     if (isFriend) {
1470       FunctionTemplate->setLexicalDeclContext(Owner);
1471       FunctionTemplate->setObjectOfFriendDecl(true);
1472     } else if (D->isOutOfLine())
1473       FunctionTemplate->setLexicalDeclContext(D->getLexicalDeclContext());
1474     Method->setDescribedFunctionTemplate(FunctionTemplate);
1475   } else if (FunctionTemplate) {
1476     // Record this function template specialization.
1477     std::pair<const TemplateArgument *, unsigned> Innermost
1478       = TemplateArgs.getInnermost();
1479     Method->setFunctionTemplateSpecialization(FunctionTemplate,
1480                          TemplateArgumentList::CreateCopy(SemaRef.Context,
1481                                                           Innermost.first,
1482                                                           Innermost.second),
1483                                               /*InsertPos=*/0);
1484   } else if (!isFriend) {
1485     // Record that this is an instantiation of a member function.
1486     Method->setInstantiationOfMemberFunction(D, TSK_ImplicitInstantiation);
1487   }
1488 
1489   // If we are instantiating a member function defined
1490   // out-of-line, the instantiation will have the same lexical
1491   // context (which will be a namespace scope) as the template.
1492   if (isFriend) {
1493     if (NumTempParamLists)
1494       Method->setTemplateParameterListsInfo(SemaRef.Context,
1495                                             NumTempParamLists,
1496                                             TempParamLists.data());
1497 
1498     Method->setLexicalDeclContext(Owner);
1499     Method->setObjectOfFriendDecl(true);
1500   } else if (D->isOutOfLine())
1501     Method->setLexicalDeclContext(D->getLexicalDeclContext());
1502 
1503   // Attach the parameters
1504   for (unsigned P = 0; P < Params.size(); ++P)
1505     Params[P]->setOwningFunction(Method);
1506   Method->setParams(Params);
1507 
1508   if (InitMethodInstantiation(Method, D))
1509     Method->setInvalidDecl();
1510 
1511   LookupResult Previous(SemaRef, NameInfo, Sema::LookupOrdinaryName,
1512                         Sema::ForRedeclaration);
1513 
1514   if (!FunctionTemplate || TemplateParams || isFriend) {
1515     SemaRef.LookupQualifiedName(Previous, Record);
1516 
1517     // In C++, the previous declaration we find might be a tag type
1518     // (class or enum). In this case, the new declaration will hide the
1519     // tag type. Note that this does does not apply if we're declaring a
1520     // typedef (C++ [dcl.typedef]p4).
1521     if (Previous.isSingleTagDecl())
1522       Previous.clear();
1523   }
1524 
1525   if (!IsClassScopeSpecialization)
1526     SemaRef.CheckFunctionDeclaration(0, Method, Previous, false);
1527 
1528   if (D->isPure())
1529     SemaRef.CheckPureMethod(Method, SourceRange());
1530 
1531   // Propagate access.  For a non-friend declaration, the access is
1532   // whatever we're propagating from.  For a friend, it should be the
1533   // previous declaration we just found.
1534   if (isFriend && Method->getPreviousDecl())
1535     Method->setAccess(Method->getPreviousDecl()->getAccess());
1536   else
1537     Method->setAccess(D->getAccess());
1538   if (FunctionTemplate)
1539     FunctionTemplate->setAccess(Method->getAccess());
1540 
1541   SemaRef.CheckOverrideControl(Method);
1542 
1543   // If a function is defined as defaulted or deleted, mark it as such now.
1544   if (D->isDefaulted())
1545     Method->setDefaulted();
1546   if (D->isDeletedAsWritten())
1547     Method->setDeletedAsWritten();
1548 
1549   // If there's a function template, let our caller handle it.
1550   if (FunctionTemplate) {
1551     // do nothing
1552 
1553   // Don't hide a (potentially) valid declaration with an invalid one.
1554   } else if (Method->isInvalidDecl() && !Previous.empty()) {
1555     // do nothing
1556 
1557   // Otherwise, check access to friends and make them visible.
1558   } else if (isFriend) {
1559     // We only need to re-check access for methods which we didn't
1560     // manage to match during parsing.
1561     if (!D->getPreviousDecl())
1562       SemaRef.CheckFriendAccess(Method);
1563 
1564     Record->makeDeclVisibleInContext(Method);
1565 
1566   // Otherwise, add the declaration.  We don't need to do this for
1567   // class-scope specializations because we'll have matched them with
1568   // the appropriate template.
1569   } else if (!IsClassScopeSpecialization) {
1570     Owner->addDecl(Method);
1571   }
1572 
1573   if (D->isExplicitlyDefaulted()) {
1574     SemaRef.SetDeclDefaulted(Method, Method->getLocation());
1575   } else {
1576     assert(!D->isDefaulted() &&
1577            "should not implicitly default uninstantiated function");
1578   }
1579 
1580   return Method;
1581 }
1582 
VisitCXXConstructorDecl(CXXConstructorDecl * D)1583 Decl *TemplateDeclInstantiator::VisitCXXConstructorDecl(CXXConstructorDecl *D) {
1584   return VisitCXXMethodDecl(D);
1585 }
1586 
VisitCXXDestructorDecl(CXXDestructorDecl * D)1587 Decl *TemplateDeclInstantiator::VisitCXXDestructorDecl(CXXDestructorDecl *D) {
1588   return VisitCXXMethodDecl(D);
1589 }
1590 
VisitCXXConversionDecl(CXXConversionDecl * D)1591 Decl *TemplateDeclInstantiator::VisitCXXConversionDecl(CXXConversionDecl *D) {
1592   return VisitCXXMethodDecl(D);
1593 }
1594 
VisitParmVarDecl(ParmVarDecl * D)1595 ParmVarDecl *TemplateDeclInstantiator::VisitParmVarDecl(ParmVarDecl *D) {
1596   return SemaRef.SubstParmVarDecl(D, TemplateArgs, /*indexAdjustment*/ 0,
1597                                   llvm::Optional<unsigned>(),
1598                                   /*ExpectParameterPack=*/false);
1599 }
1600 
VisitTemplateTypeParmDecl(TemplateTypeParmDecl * D)1601 Decl *TemplateDeclInstantiator::VisitTemplateTypeParmDecl(
1602                                                     TemplateTypeParmDecl *D) {
1603   // TODO: don't always clone when decls are refcounted.
1604   assert(D->getTypeForDecl()->isTemplateTypeParmType());
1605 
1606   TemplateTypeParmDecl *Inst =
1607     TemplateTypeParmDecl::Create(SemaRef.Context, Owner,
1608                                  D->getLocStart(), D->getLocation(),
1609                                  D->getDepth() - TemplateArgs.getNumLevels(),
1610                                  D->getIndex(), D->getIdentifier(),
1611                                  D->wasDeclaredWithTypename(),
1612                                  D->isParameterPack());
1613   Inst->setAccess(AS_public);
1614 
1615   if (D->hasDefaultArgument())
1616     Inst->setDefaultArgument(D->getDefaultArgumentInfo(), false);
1617 
1618   // Introduce this template parameter's instantiation into the instantiation
1619   // scope.
1620   SemaRef.CurrentInstantiationScope->InstantiatedLocal(D, Inst);
1621 
1622   return Inst;
1623 }
1624 
VisitNonTypeTemplateParmDecl(NonTypeTemplateParmDecl * D)1625 Decl *TemplateDeclInstantiator::VisitNonTypeTemplateParmDecl(
1626                                                  NonTypeTemplateParmDecl *D) {
1627   // Substitute into the type of the non-type template parameter.
1628   TypeLoc TL = D->getTypeSourceInfo()->getTypeLoc();
1629   SmallVector<TypeSourceInfo *, 4> ExpandedParameterPackTypesAsWritten;
1630   SmallVector<QualType, 4> ExpandedParameterPackTypes;
1631   bool IsExpandedParameterPack = false;
1632   TypeSourceInfo *DI;
1633   QualType T;
1634   bool Invalid = false;
1635 
1636   if (D->isExpandedParameterPack()) {
1637     // The non-type template parameter pack is an already-expanded pack
1638     // expansion of types. Substitute into each of the expanded types.
1639     ExpandedParameterPackTypes.reserve(D->getNumExpansionTypes());
1640     ExpandedParameterPackTypesAsWritten.reserve(D->getNumExpansionTypes());
1641     for (unsigned I = 0, N = D->getNumExpansionTypes(); I != N; ++I) {
1642       TypeSourceInfo *NewDI =SemaRef.SubstType(D->getExpansionTypeSourceInfo(I),
1643                                                TemplateArgs,
1644                                                D->getLocation(),
1645                                                D->getDeclName());
1646       if (!NewDI)
1647         return 0;
1648 
1649       ExpandedParameterPackTypesAsWritten.push_back(NewDI);
1650       QualType NewT =SemaRef.CheckNonTypeTemplateParameterType(NewDI->getType(),
1651                                                               D->getLocation());
1652       if (NewT.isNull())
1653         return 0;
1654       ExpandedParameterPackTypes.push_back(NewT);
1655     }
1656 
1657     IsExpandedParameterPack = true;
1658     DI = D->getTypeSourceInfo();
1659     T = DI->getType();
1660   } else if (D->isPackExpansion()) {
1661     // The non-type template parameter pack's type is a pack expansion of types.
1662     // Determine whether we need to expand this parameter pack into separate
1663     // types.
1664     PackExpansionTypeLoc Expansion = cast<PackExpansionTypeLoc>(TL);
1665     TypeLoc Pattern = Expansion.getPatternLoc();
1666     SmallVector<UnexpandedParameterPack, 2> Unexpanded;
1667     SemaRef.collectUnexpandedParameterPacks(Pattern, Unexpanded);
1668 
1669     // Determine whether the set of unexpanded parameter packs can and should
1670     // be expanded.
1671     bool Expand = true;
1672     bool RetainExpansion = false;
1673     llvm::Optional<unsigned> OrigNumExpansions
1674       = Expansion.getTypePtr()->getNumExpansions();
1675     llvm::Optional<unsigned> NumExpansions = OrigNumExpansions;
1676     if (SemaRef.CheckParameterPacksForExpansion(Expansion.getEllipsisLoc(),
1677                                                 Pattern.getSourceRange(),
1678                                                 Unexpanded,
1679                                                 TemplateArgs,
1680                                                 Expand, RetainExpansion,
1681                                                 NumExpansions))
1682       return 0;
1683 
1684     if (Expand) {
1685       for (unsigned I = 0; I != *NumExpansions; ++I) {
1686         Sema::ArgumentPackSubstitutionIndexRAII SubstIndex(SemaRef, I);
1687         TypeSourceInfo *NewDI = SemaRef.SubstType(Pattern, TemplateArgs,
1688                                                   D->getLocation(),
1689                                                   D->getDeclName());
1690         if (!NewDI)
1691           return 0;
1692 
1693         ExpandedParameterPackTypesAsWritten.push_back(NewDI);
1694         QualType NewT = SemaRef.CheckNonTypeTemplateParameterType(
1695                                                               NewDI->getType(),
1696                                                               D->getLocation());
1697         if (NewT.isNull())
1698           return 0;
1699         ExpandedParameterPackTypes.push_back(NewT);
1700       }
1701 
1702       // Note that we have an expanded parameter pack. The "type" of this
1703       // expanded parameter pack is the original expansion type, but callers
1704       // will end up using the expanded parameter pack types for type-checking.
1705       IsExpandedParameterPack = true;
1706       DI = D->getTypeSourceInfo();
1707       T = DI->getType();
1708     } else {
1709       // We cannot fully expand the pack expansion now, so substitute into the
1710       // pattern and create a new pack expansion type.
1711       Sema::ArgumentPackSubstitutionIndexRAII SubstIndex(SemaRef, -1);
1712       TypeSourceInfo *NewPattern = SemaRef.SubstType(Pattern, TemplateArgs,
1713                                                      D->getLocation(),
1714                                                      D->getDeclName());
1715       if (!NewPattern)
1716         return 0;
1717 
1718       DI = SemaRef.CheckPackExpansion(NewPattern, Expansion.getEllipsisLoc(),
1719                                       NumExpansions);
1720       if (!DI)
1721         return 0;
1722 
1723       T = DI->getType();
1724     }
1725   } else {
1726     // Simple case: substitution into a parameter that is not a parameter pack.
1727     DI = SemaRef.SubstType(D->getTypeSourceInfo(), TemplateArgs,
1728                            D->getLocation(), D->getDeclName());
1729     if (!DI)
1730       return 0;
1731 
1732     // Check that this type is acceptable for a non-type template parameter.
1733     T = SemaRef.CheckNonTypeTemplateParameterType(DI->getType(),
1734                                                   D->getLocation());
1735     if (T.isNull()) {
1736       T = SemaRef.Context.IntTy;
1737       Invalid = true;
1738     }
1739   }
1740 
1741   NonTypeTemplateParmDecl *Param;
1742   if (IsExpandedParameterPack)
1743     Param = NonTypeTemplateParmDecl::Create(SemaRef.Context, Owner,
1744                                             D->getInnerLocStart(),
1745                                             D->getLocation(),
1746                                     D->getDepth() - TemplateArgs.getNumLevels(),
1747                                             D->getPosition(),
1748                                             D->getIdentifier(), T,
1749                                             DI,
1750                                             ExpandedParameterPackTypes.data(),
1751                                             ExpandedParameterPackTypes.size(),
1752                                     ExpandedParameterPackTypesAsWritten.data());
1753   else
1754     Param = NonTypeTemplateParmDecl::Create(SemaRef.Context, Owner,
1755                                             D->getInnerLocStart(),
1756                                             D->getLocation(),
1757                                     D->getDepth() - TemplateArgs.getNumLevels(),
1758                                             D->getPosition(),
1759                                             D->getIdentifier(), T,
1760                                             D->isParameterPack(), DI);
1761 
1762   Param->setAccess(AS_public);
1763   if (Invalid)
1764     Param->setInvalidDecl();
1765 
1766   Param->setDefaultArgument(D->getDefaultArgument(), false);
1767 
1768   // Introduce this template parameter's instantiation into the instantiation
1769   // scope.
1770   SemaRef.CurrentInstantiationScope->InstantiatedLocal(D, Param);
1771   return Param;
1772 }
1773 
collectUnexpandedParameterPacks(Sema & S,TemplateParameterList * Params,SmallVectorImpl<UnexpandedParameterPack> & Unexpanded)1774 static void collectUnexpandedParameterPacks(
1775     Sema &S,
1776     TemplateParameterList *Params,
1777     SmallVectorImpl<UnexpandedParameterPack> &Unexpanded) {
1778   for (TemplateParameterList::const_iterator I = Params->begin(),
1779                                              E = Params->end(); I != E; ++I) {
1780     if ((*I)->isTemplateParameterPack())
1781       continue;
1782     if (NonTypeTemplateParmDecl *NTTP = dyn_cast<NonTypeTemplateParmDecl>(*I))
1783       S.collectUnexpandedParameterPacks(NTTP->getTypeSourceInfo()->getTypeLoc(),
1784                                         Unexpanded);
1785     if (TemplateTemplateParmDecl *TTP = dyn_cast<TemplateTemplateParmDecl>(*I))
1786       collectUnexpandedParameterPacks(S, TTP->getTemplateParameters(),
1787                                       Unexpanded);
1788   }
1789 }
1790 
1791 Decl *
VisitTemplateTemplateParmDecl(TemplateTemplateParmDecl * D)1792 TemplateDeclInstantiator::VisitTemplateTemplateParmDecl(
1793                                                   TemplateTemplateParmDecl *D) {
1794   // Instantiate the template parameter list of the template template parameter.
1795   TemplateParameterList *TempParams = D->getTemplateParameters();
1796   TemplateParameterList *InstParams;
1797   SmallVector<TemplateParameterList*, 8> ExpandedParams;
1798 
1799   bool IsExpandedParameterPack = false;
1800 
1801   if (D->isExpandedParameterPack()) {
1802     // The template template parameter pack is an already-expanded pack
1803     // expansion of template parameters. Substitute into each of the expanded
1804     // parameters.
1805     ExpandedParams.reserve(D->getNumExpansionTemplateParameters());
1806     for (unsigned I = 0, N = D->getNumExpansionTemplateParameters();
1807          I != N; ++I) {
1808       LocalInstantiationScope Scope(SemaRef);
1809       TemplateParameterList *Expansion =
1810         SubstTemplateParams(D->getExpansionTemplateParameters(I));
1811       if (!Expansion)
1812         return 0;
1813       ExpandedParams.push_back(Expansion);
1814     }
1815 
1816     IsExpandedParameterPack = true;
1817     InstParams = TempParams;
1818   } else if (D->isPackExpansion()) {
1819     // The template template parameter pack expands to a pack of template
1820     // template parameters. Determine whether we need to expand this parameter
1821     // pack into separate parameters.
1822     SmallVector<UnexpandedParameterPack, 2> Unexpanded;
1823     collectUnexpandedParameterPacks(SemaRef, D->getTemplateParameters(),
1824                                     Unexpanded);
1825 
1826     // Determine whether the set of unexpanded parameter packs can and should
1827     // be expanded.
1828     bool Expand = true;
1829     bool RetainExpansion = false;
1830     llvm::Optional<unsigned> NumExpansions;
1831     if (SemaRef.CheckParameterPacksForExpansion(D->getLocation(),
1832                                                 TempParams->getSourceRange(),
1833                                                 Unexpanded,
1834                                                 TemplateArgs,
1835                                                 Expand, RetainExpansion,
1836                                                 NumExpansions))
1837       return 0;
1838 
1839     if (Expand) {
1840       for (unsigned I = 0; I != *NumExpansions; ++I) {
1841         Sema::ArgumentPackSubstitutionIndexRAII SubstIndex(SemaRef, I);
1842         LocalInstantiationScope Scope(SemaRef);
1843         TemplateParameterList *Expansion = SubstTemplateParams(TempParams);
1844         if (!Expansion)
1845           return 0;
1846         ExpandedParams.push_back(Expansion);
1847       }
1848 
1849       // Note that we have an expanded parameter pack. The "type" of this
1850       // expanded parameter pack is the original expansion type, but callers
1851       // will end up using the expanded parameter pack types for type-checking.
1852       IsExpandedParameterPack = true;
1853       InstParams = TempParams;
1854     } else {
1855       // We cannot fully expand the pack expansion now, so just substitute
1856       // into the pattern.
1857       Sema::ArgumentPackSubstitutionIndexRAII SubstIndex(SemaRef, -1);
1858 
1859       LocalInstantiationScope Scope(SemaRef);
1860       InstParams = SubstTemplateParams(TempParams);
1861       if (!InstParams)
1862         return 0;
1863     }
1864   } else {
1865     // Perform the actual substitution of template parameters within a new,
1866     // local instantiation scope.
1867     LocalInstantiationScope Scope(SemaRef);
1868     InstParams = SubstTemplateParams(TempParams);
1869     if (!InstParams)
1870       return 0;
1871   }
1872 
1873   // Build the template template parameter.
1874   TemplateTemplateParmDecl *Param;
1875   if (IsExpandedParameterPack)
1876     Param = TemplateTemplateParmDecl::Create(SemaRef.Context, Owner,
1877                                              D->getLocation(),
1878                                    D->getDepth() - TemplateArgs.getNumLevels(),
1879                                              D->getPosition(),
1880                                              D->getIdentifier(), InstParams,
1881                                              ExpandedParams);
1882   else
1883     Param = TemplateTemplateParmDecl::Create(SemaRef.Context, Owner,
1884                                              D->getLocation(),
1885                                    D->getDepth() - TemplateArgs.getNumLevels(),
1886                                              D->getPosition(),
1887                                              D->isParameterPack(),
1888                                              D->getIdentifier(), InstParams);
1889   Param->setDefaultArgument(D->getDefaultArgument(), false);
1890   Param->setAccess(AS_public);
1891 
1892   // Introduce this template parameter's instantiation into the instantiation
1893   // scope.
1894   SemaRef.CurrentInstantiationScope->InstantiatedLocal(D, Param);
1895 
1896   return Param;
1897 }
1898 
VisitUsingDirectiveDecl(UsingDirectiveDecl * D)1899 Decl *TemplateDeclInstantiator::VisitUsingDirectiveDecl(UsingDirectiveDecl *D) {
1900   // Using directives are never dependent (and never contain any types or
1901   // expressions), so they require no explicit instantiation work.
1902 
1903   UsingDirectiveDecl *Inst
1904     = UsingDirectiveDecl::Create(SemaRef.Context, Owner, D->getLocation(),
1905                                  D->getNamespaceKeyLocation(),
1906                                  D->getQualifierLoc(),
1907                                  D->getIdentLocation(),
1908                                  D->getNominatedNamespace(),
1909                                  D->getCommonAncestor());
1910 
1911   // Add the using directive to its declaration context
1912   // only if this is not a function or method.
1913   if (!Owner->isFunctionOrMethod())
1914     Owner->addDecl(Inst);
1915 
1916   return Inst;
1917 }
1918 
VisitUsingDecl(UsingDecl * D)1919 Decl *TemplateDeclInstantiator::VisitUsingDecl(UsingDecl *D) {
1920 
1921   // The nested name specifier may be dependent, for example
1922   //     template <typename T> struct t {
1923   //       struct s1 { T f1(); };
1924   //       struct s2 : s1 { using s1::f1; };
1925   //     };
1926   //     template struct t<int>;
1927   // Here, in using s1::f1, s1 refers to t<T>::s1;
1928   // we need to substitute for t<int>::s1.
1929   NestedNameSpecifierLoc QualifierLoc
1930     = SemaRef.SubstNestedNameSpecifierLoc(D->getQualifierLoc(),
1931                                           TemplateArgs);
1932   if (!QualifierLoc)
1933     return 0;
1934 
1935   // The name info is non-dependent, so no transformation
1936   // is required.
1937   DeclarationNameInfo NameInfo = D->getNameInfo();
1938 
1939   // We only need to do redeclaration lookups if we're in a class
1940   // scope (in fact, it's not really even possible in non-class
1941   // scopes).
1942   bool CheckRedeclaration = Owner->isRecord();
1943 
1944   LookupResult Prev(SemaRef, NameInfo, Sema::LookupUsingDeclName,
1945                     Sema::ForRedeclaration);
1946 
1947   UsingDecl *NewUD = UsingDecl::Create(SemaRef.Context, Owner,
1948                                        D->getUsingLocation(),
1949                                        QualifierLoc,
1950                                        NameInfo,
1951                                        D->isTypeName());
1952 
1953   CXXScopeSpec SS;
1954   SS.Adopt(QualifierLoc);
1955   if (CheckRedeclaration) {
1956     Prev.setHideTags(false);
1957     SemaRef.LookupQualifiedName(Prev, Owner);
1958 
1959     // Check for invalid redeclarations.
1960     if (SemaRef.CheckUsingDeclRedeclaration(D->getUsingLocation(),
1961                                             D->isTypeName(), SS,
1962                                             D->getLocation(), Prev))
1963       NewUD->setInvalidDecl();
1964 
1965   }
1966 
1967   if (!NewUD->isInvalidDecl() &&
1968       SemaRef.CheckUsingDeclQualifier(D->getUsingLocation(), SS,
1969                                       D->getLocation()))
1970     NewUD->setInvalidDecl();
1971 
1972   SemaRef.Context.setInstantiatedFromUsingDecl(NewUD, D);
1973   NewUD->setAccess(D->getAccess());
1974   Owner->addDecl(NewUD);
1975 
1976   // Don't process the shadow decls for an invalid decl.
1977   if (NewUD->isInvalidDecl())
1978     return NewUD;
1979 
1980   if (NameInfo.getName().getNameKind() == DeclarationName::CXXConstructorName) {
1981     if (SemaRef.CheckInheritingConstructorUsingDecl(NewUD))
1982       NewUD->setInvalidDecl();
1983     return NewUD;
1984   }
1985 
1986   bool isFunctionScope = Owner->isFunctionOrMethod();
1987 
1988   // Process the shadow decls.
1989   for (UsingDecl::shadow_iterator I = D->shadow_begin(), E = D->shadow_end();
1990          I != E; ++I) {
1991     UsingShadowDecl *Shadow = *I;
1992     NamedDecl *InstTarget =
1993       cast_or_null<NamedDecl>(SemaRef.FindInstantiatedDecl(
1994                                                           Shadow->getLocation(),
1995                                                         Shadow->getTargetDecl(),
1996                                                            TemplateArgs));
1997     if (!InstTarget)
1998       return 0;
1999 
2000     if (CheckRedeclaration &&
2001         SemaRef.CheckUsingShadowDecl(NewUD, InstTarget, Prev))
2002       continue;
2003 
2004     UsingShadowDecl *InstShadow
2005       = SemaRef.BuildUsingShadowDecl(/*Scope*/ 0, NewUD, InstTarget);
2006     SemaRef.Context.setInstantiatedFromUsingShadowDecl(InstShadow, Shadow);
2007 
2008     if (isFunctionScope)
2009       SemaRef.CurrentInstantiationScope->InstantiatedLocal(Shadow, InstShadow);
2010   }
2011 
2012   return NewUD;
2013 }
2014 
VisitUsingShadowDecl(UsingShadowDecl * D)2015 Decl *TemplateDeclInstantiator::VisitUsingShadowDecl(UsingShadowDecl *D) {
2016   // Ignore these;  we handle them in bulk when processing the UsingDecl.
2017   return 0;
2018 }
2019 
2020 Decl * TemplateDeclInstantiator
VisitUnresolvedUsingTypenameDecl(UnresolvedUsingTypenameDecl * D)2021     ::VisitUnresolvedUsingTypenameDecl(UnresolvedUsingTypenameDecl *D) {
2022   NestedNameSpecifierLoc QualifierLoc
2023     = SemaRef.SubstNestedNameSpecifierLoc(D->getQualifierLoc(),
2024                                           TemplateArgs);
2025   if (!QualifierLoc)
2026     return 0;
2027 
2028   CXXScopeSpec SS;
2029   SS.Adopt(QualifierLoc);
2030 
2031   // Since NameInfo refers to a typename, it cannot be a C++ special name.
2032   // Hence, no tranformation is required for it.
2033   DeclarationNameInfo NameInfo(D->getDeclName(), D->getLocation());
2034   NamedDecl *UD =
2035     SemaRef.BuildUsingDeclaration(/*Scope*/ 0, D->getAccess(),
2036                                   D->getUsingLoc(), SS, NameInfo, 0,
2037                                   /*instantiation*/ true,
2038                                   /*typename*/ true, D->getTypenameLoc());
2039   if (UD)
2040     SemaRef.Context.setInstantiatedFromUsingDecl(cast<UsingDecl>(UD), D);
2041 
2042   return UD;
2043 }
2044 
2045 Decl * TemplateDeclInstantiator
VisitUnresolvedUsingValueDecl(UnresolvedUsingValueDecl * D)2046     ::VisitUnresolvedUsingValueDecl(UnresolvedUsingValueDecl *D) {
2047   NestedNameSpecifierLoc QualifierLoc
2048       = SemaRef.SubstNestedNameSpecifierLoc(D->getQualifierLoc(), TemplateArgs);
2049   if (!QualifierLoc)
2050     return 0;
2051 
2052   CXXScopeSpec SS;
2053   SS.Adopt(QualifierLoc);
2054 
2055   DeclarationNameInfo NameInfo
2056     = SemaRef.SubstDeclarationNameInfo(D->getNameInfo(), TemplateArgs);
2057 
2058   NamedDecl *UD =
2059     SemaRef.BuildUsingDeclaration(/*Scope*/ 0, D->getAccess(),
2060                                   D->getUsingLoc(), SS, NameInfo, 0,
2061                                   /*instantiation*/ true,
2062                                   /*typename*/ false, SourceLocation());
2063   if (UD)
2064     SemaRef.Context.setInstantiatedFromUsingDecl(cast<UsingDecl>(UD), D);
2065 
2066   return UD;
2067 }
2068 
2069 
VisitClassScopeFunctionSpecializationDecl(ClassScopeFunctionSpecializationDecl * Decl)2070 Decl *TemplateDeclInstantiator::VisitClassScopeFunctionSpecializationDecl(
2071                                      ClassScopeFunctionSpecializationDecl *Decl) {
2072   CXXMethodDecl *OldFD = Decl->getSpecialization();
2073   CXXMethodDecl *NewFD = cast<CXXMethodDecl>(VisitCXXMethodDecl(OldFD,
2074                                                                 0, true));
2075 
2076   LookupResult Previous(SemaRef, NewFD->getNameInfo(), Sema::LookupOrdinaryName,
2077                         Sema::ForRedeclaration);
2078 
2079   TemplateArgumentListInfo TemplateArgs;
2080   TemplateArgumentListInfo* TemplateArgsPtr = 0;
2081   if (Decl->hasExplicitTemplateArgs()) {
2082     TemplateArgs = Decl->templateArgs();
2083     TemplateArgsPtr = &TemplateArgs;
2084   }
2085 
2086   SemaRef.LookupQualifiedName(Previous, SemaRef.CurContext);
2087   if (SemaRef.CheckFunctionTemplateSpecialization(NewFD, TemplateArgsPtr,
2088                                                   Previous)) {
2089     NewFD->setInvalidDecl();
2090     return NewFD;
2091   }
2092 
2093   // Associate the specialization with the pattern.
2094   FunctionDecl *Specialization = cast<FunctionDecl>(Previous.getFoundDecl());
2095   assert(Specialization && "Class scope Specialization is null");
2096   SemaRef.Context.setClassScopeSpecializationPattern(Specialization, OldFD);
2097 
2098   return NewFD;
2099 }
2100 
SubstDecl(Decl * D,DeclContext * Owner,const MultiLevelTemplateArgumentList & TemplateArgs)2101 Decl *Sema::SubstDecl(Decl *D, DeclContext *Owner,
2102                       const MultiLevelTemplateArgumentList &TemplateArgs) {
2103   TemplateDeclInstantiator Instantiator(*this, Owner, TemplateArgs);
2104   if (D->isInvalidDecl())
2105     return 0;
2106 
2107   return Instantiator.Visit(D);
2108 }
2109 
2110 /// \brief Instantiates a nested template parameter list in the current
2111 /// instantiation context.
2112 ///
2113 /// \param L The parameter list to instantiate
2114 ///
2115 /// \returns NULL if there was an error
2116 TemplateParameterList *
SubstTemplateParams(TemplateParameterList * L)2117 TemplateDeclInstantiator::SubstTemplateParams(TemplateParameterList *L) {
2118   // Get errors for all the parameters before bailing out.
2119   bool Invalid = false;
2120 
2121   unsigned N = L->size();
2122   typedef SmallVector<NamedDecl *, 8> ParamVector;
2123   ParamVector Params;
2124   Params.reserve(N);
2125   for (TemplateParameterList::iterator PI = L->begin(), PE = L->end();
2126        PI != PE; ++PI) {
2127     NamedDecl *D = cast_or_null<NamedDecl>(Visit(*PI));
2128     Params.push_back(D);
2129     Invalid = Invalid || !D || D->isInvalidDecl();
2130   }
2131 
2132   // Clean up if we had an error.
2133   if (Invalid)
2134     return NULL;
2135 
2136   TemplateParameterList *InstL
2137     = TemplateParameterList::Create(SemaRef.Context, L->getTemplateLoc(),
2138                                     L->getLAngleLoc(), &Params.front(), N,
2139                                     L->getRAngleLoc());
2140   return InstL;
2141 }
2142 
2143 /// \brief Instantiate the declaration of a class template partial
2144 /// specialization.
2145 ///
2146 /// \param ClassTemplate the (instantiated) class template that is partially
2147 // specialized by the instantiation of \p PartialSpec.
2148 ///
2149 /// \param PartialSpec the (uninstantiated) class template partial
2150 /// specialization that we are instantiating.
2151 ///
2152 /// \returns The instantiated partial specialization, if successful; otherwise,
2153 /// NULL to indicate an error.
2154 ClassTemplatePartialSpecializationDecl *
InstantiateClassTemplatePartialSpecialization(ClassTemplateDecl * ClassTemplate,ClassTemplatePartialSpecializationDecl * PartialSpec)2155 TemplateDeclInstantiator::InstantiateClassTemplatePartialSpecialization(
2156                                             ClassTemplateDecl *ClassTemplate,
2157                           ClassTemplatePartialSpecializationDecl *PartialSpec) {
2158   // Create a local instantiation scope for this class template partial
2159   // specialization, which will contain the instantiations of the template
2160   // parameters.
2161   LocalInstantiationScope Scope(SemaRef);
2162 
2163   // Substitute into the template parameters of the class template partial
2164   // specialization.
2165   TemplateParameterList *TempParams = PartialSpec->getTemplateParameters();
2166   TemplateParameterList *InstParams = SubstTemplateParams(TempParams);
2167   if (!InstParams)
2168     return 0;
2169 
2170   // Substitute into the template arguments of the class template partial
2171   // specialization.
2172   TemplateArgumentListInfo InstTemplateArgs; // no angle locations
2173   if (SemaRef.Subst(PartialSpec->getTemplateArgsAsWritten(),
2174                     PartialSpec->getNumTemplateArgsAsWritten(),
2175                     InstTemplateArgs, TemplateArgs))
2176     return 0;
2177 
2178   // Check that the template argument list is well-formed for this
2179   // class template.
2180   SmallVector<TemplateArgument, 4> Converted;
2181   if (SemaRef.CheckTemplateArgumentList(ClassTemplate,
2182                                         PartialSpec->getLocation(),
2183                                         InstTemplateArgs,
2184                                         false,
2185                                         Converted))
2186     return 0;
2187 
2188   // Figure out where to insert this class template partial specialization
2189   // in the member template's set of class template partial specializations.
2190   void *InsertPos = 0;
2191   ClassTemplateSpecializationDecl *PrevDecl
2192     = ClassTemplate->findPartialSpecialization(Converted.data(),
2193                                                Converted.size(), InsertPos);
2194 
2195   // Build the canonical type that describes the converted template
2196   // arguments of the class template partial specialization.
2197   QualType CanonType
2198     = SemaRef.Context.getTemplateSpecializationType(TemplateName(ClassTemplate),
2199                                                     Converted.data(),
2200                                                     Converted.size());
2201 
2202   // Build the fully-sugared type for this class template
2203   // specialization as the user wrote in the specialization
2204   // itself. This means that we'll pretty-print the type retrieved
2205   // from the specialization's declaration the way that the user
2206   // actually wrote the specialization, rather than formatting the
2207   // name based on the "canonical" representation used to store the
2208   // template arguments in the specialization.
2209   TypeSourceInfo *WrittenTy
2210     = SemaRef.Context.getTemplateSpecializationTypeInfo(
2211                                                     TemplateName(ClassTemplate),
2212                                                     PartialSpec->getLocation(),
2213                                                     InstTemplateArgs,
2214                                                     CanonType);
2215 
2216   if (PrevDecl) {
2217     // We've already seen a partial specialization with the same template
2218     // parameters and template arguments. This can happen, for example, when
2219     // substituting the outer template arguments ends up causing two
2220     // class template partial specializations of a member class template
2221     // to have identical forms, e.g.,
2222     //
2223     //   template<typename T, typename U>
2224     //   struct Outer {
2225     //     template<typename X, typename Y> struct Inner;
2226     //     template<typename Y> struct Inner<T, Y>;
2227     //     template<typename Y> struct Inner<U, Y>;
2228     //   };
2229     //
2230     //   Outer<int, int> outer; // error: the partial specializations of Inner
2231     //                          // have the same signature.
2232     SemaRef.Diag(PartialSpec->getLocation(), diag::err_partial_spec_redeclared)
2233       << WrittenTy->getType();
2234     SemaRef.Diag(PrevDecl->getLocation(), diag::note_prev_partial_spec_here)
2235       << SemaRef.Context.getTypeDeclType(PrevDecl);
2236     return 0;
2237   }
2238 
2239 
2240   // Create the class template partial specialization declaration.
2241   ClassTemplatePartialSpecializationDecl *InstPartialSpec
2242     = ClassTemplatePartialSpecializationDecl::Create(SemaRef.Context,
2243                                                      PartialSpec->getTagKind(),
2244                                                      Owner,
2245                                                      PartialSpec->getLocStart(),
2246                                                      PartialSpec->getLocation(),
2247                                                      InstParams,
2248                                                      ClassTemplate,
2249                                                      Converted.data(),
2250                                                      Converted.size(),
2251                                                      InstTemplateArgs,
2252                                                      CanonType,
2253                                                      0,
2254                              ClassTemplate->getNextPartialSpecSequenceNumber());
2255   // Substitute the nested name specifier, if any.
2256   if (SubstQualifier(PartialSpec, InstPartialSpec))
2257     return 0;
2258 
2259   InstPartialSpec->setInstantiatedFromMember(PartialSpec);
2260   InstPartialSpec->setTypeAsWritten(WrittenTy);
2261 
2262   // Add this partial specialization to the set of class template partial
2263   // specializations.
2264   ClassTemplate->AddPartialSpecialization(InstPartialSpec, /*InsertPos=*/0);
2265   return InstPartialSpec;
2266 }
2267 
2268 TypeSourceInfo*
SubstFunctionType(FunctionDecl * D,SmallVectorImpl<ParmVarDecl * > & Params)2269 TemplateDeclInstantiator::SubstFunctionType(FunctionDecl *D,
2270                               SmallVectorImpl<ParmVarDecl *> &Params) {
2271   TypeSourceInfo *OldTInfo = D->getTypeSourceInfo();
2272   assert(OldTInfo && "substituting function without type source info");
2273   assert(Params.empty() && "parameter vector is non-empty at start");
2274 
2275   CXXRecordDecl *ThisContext = 0;
2276   unsigned ThisTypeQuals = 0;
2277   if (CXXMethodDecl *Method = dyn_cast<CXXMethodDecl>(D)) {
2278     ThisContext = Method->getParent();
2279     ThisTypeQuals = Method->getTypeQualifiers();
2280   }
2281 
2282   TypeSourceInfo *NewTInfo
2283     = SemaRef.SubstFunctionDeclType(OldTInfo, TemplateArgs,
2284                                     D->getTypeSpecStartLoc(),
2285                                     D->getDeclName(),
2286                                     ThisContext, ThisTypeQuals);
2287   if (!NewTInfo)
2288     return 0;
2289 
2290   if (NewTInfo != OldTInfo) {
2291     // Get parameters from the new type info.
2292     TypeLoc OldTL = OldTInfo->getTypeLoc().IgnoreParens();
2293     if (FunctionProtoTypeLoc *OldProtoLoc
2294                                   = dyn_cast<FunctionProtoTypeLoc>(&OldTL)) {
2295       TypeLoc NewTL = NewTInfo->getTypeLoc().IgnoreParens();
2296       FunctionProtoTypeLoc *NewProtoLoc = cast<FunctionProtoTypeLoc>(&NewTL);
2297       assert(NewProtoLoc && "Missing prototype?");
2298       unsigned NewIdx = 0;
2299       for (unsigned OldIdx = 0, NumOldParams = OldProtoLoc->getNumArgs();
2300            OldIdx != NumOldParams; ++OldIdx) {
2301         ParmVarDecl *OldParam = OldProtoLoc->getArg(OldIdx);
2302         LocalInstantiationScope *Scope = SemaRef.CurrentInstantiationScope;
2303 
2304         llvm::Optional<unsigned> NumArgumentsInExpansion;
2305         if (OldParam->isParameterPack())
2306           NumArgumentsInExpansion =
2307               SemaRef.getNumArgumentsInExpansion(OldParam->getType(),
2308                                                  TemplateArgs);
2309         if (!NumArgumentsInExpansion) {
2310           // Simple case: normal parameter, or a parameter pack that's
2311           // instantiated to a (still-dependent) parameter pack.
2312           ParmVarDecl *NewParam = NewProtoLoc->getArg(NewIdx++);
2313           Params.push_back(NewParam);
2314           Scope->InstantiatedLocal(OldParam, NewParam);
2315         } else {
2316           // Parameter pack expansion: make the instantiation an argument pack.
2317           Scope->MakeInstantiatedLocalArgPack(OldParam);
2318           for (unsigned I = 0; I != *NumArgumentsInExpansion; ++I) {
2319             ParmVarDecl *NewParam = NewProtoLoc->getArg(NewIdx++);
2320             Params.push_back(NewParam);
2321             Scope->InstantiatedLocalPackArg(OldParam, NewParam);
2322           }
2323         }
2324       }
2325     }
2326   } else {
2327     // The function type itself was not dependent and therefore no
2328     // substitution occurred. However, we still need to instantiate
2329     // the function parameters themselves.
2330     TypeLoc OldTL = OldTInfo->getTypeLoc().IgnoreParens();
2331     if (FunctionProtoTypeLoc *OldProtoLoc
2332                                     = dyn_cast<FunctionProtoTypeLoc>(&OldTL)) {
2333       for (unsigned i = 0, i_end = OldProtoLoc->getNumArgs(); i != i_end; ++i) {
2334         ParmVarDecl *Parm = VisitParmVarDecl(OldProtoLoc->getArg(i));
2335         if (!Parm)
2336           return 0;
2337         Params.push_back(Parm);
2338       }
2339     }
2340   }
2341   return NewTInfo;
2342 }
2343 
2344 /// Introduce the instantiated function parameters into the local
2345 /// instantiation scope, and set the parameter names to those used
2346 /// in the template.
addInstantiatedParametersToScope(Sema & S,FunctionDecl * Function,const FunctionDecl * PatternDecl,LocalInstantiationScope & Scope,const MultiLevelTemplateArgumentList & TemplateArgs)2347 static void addInstantiatedParametersToScope(Sema &S, FunctionDecl *Function,
2348                                              const FunctionDecl *PatternDecl,
2349                                              LocalInstantiationScope &Scope,
2350                            const MultiLevelTemplateArgumentList &TemplateArgs) {
2351   unsigned FParamIdx = 0;
2352   for (unsigned I = 0, N = PatternDecl->getNumParams(); I != N; ++I) {
2353     const ParmVarDecl *PatternParam = PatternDecl->getParamDecl(I);
2354     if (!PatternParam->isParameterPack()) {
2355       // Simple case: not a parameter pack.
2356       assert(FParamIdx < Function->getNumParams());
2357       ParmVarDecl *FunctionParam = Function->getParamDecl(FParamIdx);
2358       FunctionParam->setDeclName(PatternParam->getDeclName());
2359       Scope.InstantiatedLocal(PatternParam, FunctionParam);
2360       ++FParamIdx;
2361       continue;
2362     }
2363 
2364     // Expand the parameter pack.
2365     Scope.MakeInstantiatedLocalArgPack(PatternParam);
2366     llvm::Optional<unsigned> NumArgumentsInExpansion
2367       = S.getNumArgumentsInExpansion(PatternParam->getType(), TemplateArgs);
2368     assert(NumArgumentsInExpansion &&
2369            "should only be called when all template arguments are known");
2370     for (unsigned Arg = 0; Arg < *NumArgumentsInExpansion; ++Arg) {
2371       ParmVarDecl *FunctionParam = Function->getParamDecl(FParamIdx);
2372       FunctionParam->setDeclName(PatternParam->getDeclName());
2373       Scope.InstantiatedLocalPackArg(PatternParam, FunctionParam);
2374       ++FParamIdx;
2375     }
2376   }
2377 }
2378 
InstantiateExceptionSpec(Sema & SemaRef,FunctionDecl * New,const FunctionProtoType * Proto,const MultiLevelTemplateArgumentList & TemplateArgs)2379 static void InstantiateExceptionSpec(Sema &SemaRef, FunctionDecl *New,
2380                                      const FunctionProtoType *Proto,
2381                            const MultiLevelTemplateArgumentList &TemplateArgs) {
2382   assert(Proto->getExceptionSpecType() != EST_Uninstantiated);
2383 
2384   // C++11 [expr.prim.general]p3:
2385   //   If a declaration declares a member function or member function
2386   //   template of a class X, the expression this is a prvalue of type
2387   //   "pointer to cv-qualifier-seq X" between the optional cv-qualifer-seq
2388   //   and the end of the function-definition, member-declarator, or
2389   //   declarator.
2390   CXXRecordDecl *ThisContext = 0;
2391   unsigned ThisTypeQuals = 0;
2392   if (CXXMethodDecl *Method = dyn_cast<CXXMethodDecl>(New)) {
2393     ThisContext = Method->getParent();
2394     ThisTypeQuals = Method->getTypeQualifiers();
2395   }
2396   Sema::CXXThisScopeRAII ThisScope(SemaRef, ThisContext, ThisTypeQuals,
2397                                    SemaRef.getLangOpts().CPlusPlus0x);
2398 
2399   // The function has an exception specification or a "noreturn"
2400   // attribute. Substitute into each of the exception types.
2401   SmallVector<QualType, 4> Exceptions;
2402   for (unsigned I = 0, N = Proto->getNumExceptions(); I != N; ++I) {
2403     // FIXME: Poor location information!
2404     if (const PackExpansionType *PackExpansion
2405           = Proto->getExceptionType(I)->getAs<PackExpansionType>()) {
2406       // We have a pack expansion. Instantiate it.
2407       SmallVector<UnexpandedParameterPack, 2> Unexpanded;
2408       SemaRef.collectUnexpandedParameterPacks(PackExpansion->getPattern(),
2409                                               Unexpanded);
2410       assert(!Unexpanded.empty() &&
2411              "Pack expansion without parameter packs?");
2412 
2413       bool Expand = false;
2414       bool RetainExpansion = false;
2415       llvm::Optional<unsigned> NumExpansions
2416                                         = PackExpansion->getNumExpansions();
2417       if (SemaRef.CheckParameterPacksForExpansion(New->getLocation(),
2418                                                   SourceRange(),
2419                                                   Unexpanded,
2420                                                   TemplateArgs,
2421                                                   Expand,
2422                                                   RetainExpansion,
2423                                                   NumExpansions))
2424         break;
2425 
2426       if (!Expand) {
2427         // We can't expand this pack expansion into separate arguments yet;
2428         // just substitute into the pattern and create a new pack expansion
2429         // type.
2430         Sema::ArgumentPackSubstitutionIndexRAII SubstIndex(SemaRef, -1);
2431         QualType T = SemaRef.SubstType(PackExpansion->getPattern(),
2432                                        TemplateArgs,
2433                                      New->getLocation(), New->getDeclName());
2434         if (T.isNull())
2435           break;
2436 
2437         T = SemaRef.Context.getPackExpansionType(T, NumExpansions);
2438         Exceptions.push_back(T);
2439         continue;
2440       }
2441 
2442       // Substitute into the pack expansion pattern for each template
2443       bool Invalid = false;
2444       for (unsigned ArgIdx = 0; ArgIdx != *NumExpansions; ++ArgIdx) {
2445         Sema::ArgumentPackSubstitutionIndexRAII SubstIndex(SemaRef, ArgIdx);
2446 
2447         QualType T = SemaRef.SubstType(PackExpansion->getPattern(),
2448                                        TemplateArgs,
2449                                      New->getLocation(), New->getDeclName());
2450         if (T.isNull()) {
2451           Invalid = true;
2452           break;
2453         }
2454 
2455         Exceptions.push_back(T);
2456       }
2457 
2458       if (Invalid)
2459         break;
2460 
2461       continue;
2462     }
2463 
2464     QualType T
2465       = SemaRef.SubstType(Proto->getExceptionType(I), TemplateArgs,
2466                           New->getLocation(), New->getDeclName());
2467     if (T.isNull() ||
2468         SemaRef.CheckSpecifiedExceptionType(T, New->getLocation()))
2469       continue;
2470 
2471     Exceptions.push_back(T);
2472   }
2473   Expr *NoexceptExpr = 0;
2474   if (Expr *OldNoexceptExpr = Proto->getNoexceptExpr()) {
2475     EnterExpressionEvaluationContext Unevaluated(SemaRef,
2476                                                  Sema::ConstantEvaluated);
2477     ExprResult E = SemaRef.SubstExpr(OldNoexceptExpr, TemplateArgs);
2478     if (E.isUsable())
2479       E = SemaRef.CheckBooleanCondition(E.get(), E.get()->getLocStart());
2480 
2481     if (E.isUsable()) {
2482       NoexceptExpr = E.take();
2483       if (!NoexceptExpr->isTypeDependent() &&
2484           !NoexceptExpr->isValueDependent())
2485         NoexceptExpr
2486           = SemaRef.VerifyIntegerConstantExpression(NoexceptExpr,
2487               0, diag::err_noexcept_needs_constant_expression,
2488               /*AllowFold*/ false).take();
2489     }
2490   }
2491 
2492   // Rebuild the function type
2493   const FunctionProtoType *NewProto
2494     = New->getType()->getAs<FunctionProtoType>();
2495   assert(NewProto && "Template instantiation without function prototype?");
2496 
2497   FunctionProtoType::ExtProtoInfo EPI = NewProto->getExtProtoInfo();
2498   EPI.ExceptionSpecType = Proto->getExceptionSpecType();
2499   EPI.NumExceptions = Exceptions.size();
2500   EPI.Exceptions = Exceptions.data();
2501   EPI.NoexceptExpr = NoexceptExpr;
2502 
2503   New->setType(SemaRef.Context.getFunctionType(NewProto->getResultType(),
2504                                                NewProto->arg_type_begin(),
2505                                                NewProto->getNumArgs(),
2506                                                EPI));
2507 }
2508 
InstantiateExceptionSpec(SourceLocation PointOfInstantiation,FunctionDecl * Decl)2509 void Sema::InstantiateExceptionSpec(SourceLocation PointOfInstantiation,
2510                                     FunctionDecl *Decl) {
2511   const FunctionProtoType *Proto = Decl->getType()->castAs<FunctionProtoType>();
2512   if (Proto->getExceptionSpecType() != EST_Uninstantiated)
2513     return;
2514 
2515   InstantiatingTemplate Inst(*this, PointOfInstantiation, Decl,
2516                              InstantiatingTemplate::ExceptionSpecification());
2517   if (Inst) {
2518     // We hit the instantiation depth limit. Clear the exception specification
2519     // so that our callers don't have to cope with EST_Uninstantiated.
2520     FunctionProtoType::ExtProtoInfo EPI = Proto->getExtProtoInfo();
2521     EPI.ExceptionSpecType = EST_None;
2522     Decl->setType(Context.getFunctionType(Proto->getResultType(),
2523                                           Proto->arg_type_begin(),
2524                                           Proto->getNumArgs(),
2525                                           EPI));
2526     return;
2527   }
2528 
2529   // Enter the scope of this instantiation. We don't use
2530   // PushDeclContext because we don't have a scope.
2531   Sema::ContextRAII savedContext(*this, Decl);
2532   LocalInstantiationScope Scope(*this);
2533 
2534   MultiLevelTemplateArgumentList TemplateArgs =
2535     getTemplateInstantiationArgs(Decl, 0, /*RelativeToPrimary*/true);
2536 
2537   FunctionDecl *Template = Proto->getExceptionSpecTemplate();
2538   addInstantiatedParametersToScope(*this, Decl, Template, Scope, TemplateArgs);
2539 
2540   ::InstantiateExceptionSpec(*this, Decl,
2541                              Template->getType()->castAs<FunctionProtoType>(),
2542                              TemplateArgs);
2543 }
2544 
2545 /// \brief Initializes the common fields of an instantiation function
2546 /// declaration (New) from the corresponding fields of its template (Tmpl).
2547 ///
2548 /// \returns true if there was an error
2549 bool
InitFunctionInstantiation(FunctionDecl * New,FunctionDecl * Tmpl)2550 TemplateDeclInstantiator::InitFunctionInstantiation(FunctionDecl *New,
2551                                                     FunctionDecl *Tmpl) {
2552   if (Tmpl->isDeleted())
2553     New->setDeletedAsWritten();
2554 
2555   // If we are performing substituting explicitly-specified template arguments
2556   // or deduced template arguments into a function template and we reach this
2557   // point, we are now past the point where SFINAE applies and have committed
2558   // to keeping the new function template specialization. We therefore
2559   // convert the active template instantiation for the function template
2560   // into a template instantiation for this specific function template
2561   // specialization, which is not a SFINAE context, so that we diagnose any
2562   // further errors in the declaration itself.
2563   typedef Sema::ActiveTemplateInstantiation ActiveInstType;
2564   ActiveInstType &ActiveInst = SemaRef.ActiveTemplateInstantiations.back();
2565   if (ActiveInst.Kind == ActiveInstType::ExplicitTemplateArgumentSubstitution ||
2566       ActiveInst.Kind == ActiveInstType::DeducedTemplateArgumentSubstitution) {
2567     if (FunctionTemplateDecl *FunTmpl
2568           = dyn_cast<FunctionTemplateDecl>((Decl *)ActiveInst.Entity)) {
2569       assert(FunTmpl->getTemplatedDecl() == Tmpl &&
2570              "Deduction from the wrong function template?");
2571       (void) FunTmpl;
2572       ActiveInst.Kind = ActiveInstType::TemplateInstantiation;
2573       ActiveInst.Entity = reinterpret_cast<uintptr_t>(New);
2574     }
2575   }
2576 
2577   const FunctionProtoType *Proto = Tmpl->getType()->getAs<FunctionProtoType>();
2578   assert(Proto && "Function template without prototype?");
2579 
2580   if (Proto->hasExceptionSpec() || Proto->getNoReturnAttr()) {
2581     FunctionProtoType::ExtProtoInfo EPI = Proto->getExtProtoInfo();
2582 
2583     // DR1330: In C++11, defer instantiation of a non-trivial
2584     // exception specification.
2585     if (SemaRef.getLangOpts().CPlusPlus0x &&
2586         EPI.ExceptionSpecType != EST_None &&
2587         EPI.ExceptionSpecType != EST_DynamicNone &&
2588         EPI.ExceptionSpecType != EST_BasicNoexcept) {
2589       FunctionDecl *ExceptionSpecTemplate = Tmpl;
2590       if (EPI.ExceptionSpecType == EST_Uninstantiated)
2591         ExceptionSpecTemplate = EPI.ExceptionSpecTemplate;
2592       assert(EPI.ExceptionSpecType != EST_Unevaluated &&
2593              "instantiating implicitly-declared special member");
2594 
2595       // Mark the function has having an uninstantiated exception specification.
2596       const FunctionProtoType *NewProto
2597         = New->getType()->getAs<FunctionProtoType>();
2598       assert(NewProto && "Template instantiation without function prototype?");
2599       EPI = NewProto->getExtProtoInfo();
2600       EPI.ExceptionSpecType = EST_Uninstantiated;
2601       EPI.ExceptionSpecDecl = New;
2602       EPI.ExceptionSpecTemplate = ExceptionSpecTemplate;
2603       New->setType(SemaRef.Context.getFunctionType(NewProto->getResultType(),
2604                                                    NewProto->arg_type_begin(),
2605                                                    NewProto->getNumArgs(),
2606                                                    EPI));
2607     } else {
2608       ::InstantiateExceptionSpec(SemaRef, New, Proto, TemplateArgs);
2609     }
2610   }
2611 
2612   // Get the definition. Leaves the variable unchanged if undefined.
2613   const FunctionDecl *Definition = Tmpl;
2614   Tmpl->isDefined(Definition);
2615 
2616   SemaRef.InstantiateAttrs(TemplateArgs, Definition, New,
2617                            LateAttrs, StartingScope);
2618 
2619   return false;
2620 }
2621 
2622 /// \brief Initializes common fields of an instantiated method
2623 /// declaration (New) from the corresponding fields of its template
2624 /// (Tmpl).
2625 ///
2626 /// \returns true if there was an error
2627 bool
InitMethodInstantiation(CXXMethodDecl * New,CXXMethodDecl * Tmpl)2628 TemplateDeclInstantiator::InitMethodInstantiation(CXXMethodDecl *New,
2629                                                   CXXMethodDecl *Tmpl) {
2630   if (InitFunctionInstantiation(New, Tmpl))
2631     return true;
2632 
2633   New->setAccess(Tmpl->getAccess());
2634   if (Tmpl->isVirtualAsWritten())
2635     New->setVirtualAsWritten(true);
2636 
2637   // FIXME: attributes
2638   // FIXME: New needs a pointer to Tmpl
2639   return false;
2640 }
2641 
2642 /// \brief Instantiate the definition of the given function from its
2643 /// template.
2644 ///
2645 /// \param PointOfInstantiation the point at which the instantiation was
2646 /// required. Note that this is not precisely a "point of instantiation"
2647 /// for the function, but it's close.
2648 ///
2649 /// \param Function the already-instantiated declaration of a
2650 /// function template specialization or member function of a class template
2651 /// specialization.
2652 ///
2653 /// \param Recursive if true, recursively instantiates any functions that
2654 /// are required by this instantiation.
2655 ///
2656 /// \param DefinitionRequired if true, then we are performing an explicit
2657 /// instantiation where the body of the function is required. Complain if
2658 /// there is no such body.
InstantiateFunctionDefinition(SourceLocation PointOfInstantiation,FunctionDecl * Function,bool Recursive,bool DefinitionRequired)2659 void Sema::InstantiateFunctionDefinition(SourceLocation PointOfInstantiation,
2660                                          FunctionDecl *Function,
2661                                          bool Recursive,
2662                                          bool DefinitionRequired) {
2663   if (Function->isInvalidDecl() || Function->isDefined())
2664     return;
2665 
2666   // Never instantiate an explicit specialization except if it is a class scope
2667   // explicit specialization.
2668   if (Function->getTemplateSpecializationKind() == TSK_ExplicitSpecialization &&
2669       !Function->getClassScopeSpecializationPattern())
2670     return;
2671 
2672   // Find the function body that we'll be substituting.
2673   const FunctionDecl *PatternDecl = Function->getTemplateInstantiationPattern();
2674   assert(PatternDecl && "instantiating a non-template");
2675 
2676   Stmt *Pattern = PatternDecl->getBody(PatternDecl);
2677   assert(PatternDecl && "template definition is not a template");
2678   if (!Pattern) {
2679     // Try to find a defaulted definition
2680     PatternDecl->isDefined(PatternDecl);
2681   }
2682   assert(PatternDecl && "template definition is not a template");
2683 
2684   // Postpone late parsed template instantiations.
2685   if (PatternDecl->isLateTemplateParsed() &&
2686       !LateTemplateParser) {
2687     PendingInstantiations.push_back(
2688       std::make_pair(Function, PointOfInstantiation));
2689     return;
2690   }
2691 
2692   // Call the LateTemplateParser callback if there a need to late parse
2693   // a templated function definition.
2694   if (!Pattern && PatternDecl->isLateTemplateParsed() &&
2695       LateTemplateParser) {
2696     LateTemplateParser(OpaqueParser, PatternDecl);
2697     Pattern = PatternDecl->getBody(PatternDecl);
2698   }
2699 
2700   if (!Pattern && !PatternDecl->isDefaulted()) {
2701     if (DefinitionRequired) {
2702       if (Function->getPrimaryTemplate())
2703         Diag(PointOfInstantiation,
2704              diag::err_explicit_instantiation_undefined_func_template)
2705           << Function->getPrimaryTemplate();
2706       else
2707         Diag(PointOfInstantiation,
2708              diag::err_explicit_instantiation_undefined_member)
2709           << 1 << Function->getDeclName() << Function->getDeclContext();
2710 
2711       if (PatternDecl)
2712         Diag(PatternDecl->getLocation(),
2713              diag::note_explicit_instantiation_here);
2714       Function->setInvalidDecl();
2715     } else if (Function->getTemplateSpecializationKind()
2716                  == TSK_ExplicitInstantiationDefinition) {
2717       PendingInstantiations.push_back(
2718         std::make_pair(Function, PointOfInstantiation));
2719     }
2720 
2721     return;
2722   }
2723 
2724   // C++0x [temp.explicit]p9:
2725   //   Except for inline functions, other explicit instantiation declarations
2726   //   have the effect of suppressing the implicit instantiation of the entity
2727   //   to which they refer.
2728   if (Function->getTemplateSpecializationKind()
2729         == TSK_ExplicitInstantiationDeclaration &&
2730       !PatternDecl->isInlined())
2731     return;
2732 
2733   InstantiatingTemplate Inst(*this, PointOfInstantiation, Function);
2734   if (Inst)
2735     return;
2736 
2737   // Copy the inner loc start from the pattern.
2738   Function->setInnerLocStart(PatternDecl->getInnerLocStart());
2739 
2740   // If we're performing recursive template instantiation, create our own
2741   // queue of pending implicit instantiations that we will instantiate later,
2742   // while we're still within our own instantiation context.
2743   SmallVector<VTableUse, 16> SavedVTableUses;
2744   std::deque<PendingImplicitInstantiation> SavedPendingInstantiations;
2745   if (Recursive) {
2746     VTableUses.swap(SavedVTableUses);
2747     PendingInstantiations.swap(SavedPendingInstantiations);
2748   }
2749 
2750   EnterExpressionEvaluationContext EvalContext(*this,
2751                                                Sema::PotentiallyEvaluated);
2752   ActOnStartOfFunctionDef(0, Function);
2753 
2754   // Introduce a new scope where local variable instantiations will be
2755   // recorded, unless we're actually a member function within a local
2756   // class, in which case we need to merge our results with the parent
2757   // scope (of the enclosing function).
2758   bool MergeWithParentScope = false;
2759   if (CXXRecordDecl *Rec = dyn_cast<CXXRecordDecl>(Function->getDeclContext()))
2760     MergeWithParentScope = Rec->isLocalClass();
2761 
2762   LocalInstantiationScope Scope(*this, MergeWithParentScope);
2763 
2764   // Enter the scope of this instantiation. We don't use
2765   // PushDeclContext because we don't have a scope.
2766   Sema::ContextRAII savedContext(*this, Function);
2767 
2768   MultiLevelTemplateArgumentList TemplateArgs =
2769     getTemplateInstantiationArgs(Function, 0, false, PatternDecl);
2770 
2771   addInstantiatedParametersToScope(*this, Function, PatternDecl, Scope,
2772                                    TemplateArgs);
2773 
2774   if (PatternDecl->isDefaulted()) {
2775     ActOnFinishFunctionBody(Function, 0, /*IsInstantiation=*/true);
2776 
2777     SetDeclDefaulted(Function, PatternDecl->getLocation());
2778   } else {
2779     // If this is a constructor, instantiate the member initializers.
2780     if (const CXXConstructorDecl *Ctor =
2781           dyn_cast<CXXConstructorDecl>(PatternDecl)) {
2782       InstantiateMemInitializers(cast<CXXConstructorDecl>(Function), Ctor,
2783                                  TemplateArgs);
2784     }
2785 
2786     // Instantiate the function body.
2787     StmtResult Body = SubstStmt(Pattern, TemplateArgs);
2788 
2789     if (Body.isInvalid())
2790       Function->setInvalidDecl();
2791 
2792     ActOnFinishFunctionBody(Function, Body.get(),
2793                             /*IsInstantiation=*/true);
2794   }
2795 
2796   PerformDependentDiagnostics(PatternDecl, TemplateArgs);
2797 
2798   savedContext.pop();
2799 
2800   DeclGroupRef DG(Function);
2801   Consumer.HandleTopLevelDecl(DG);
2802 
2803   // This class may have local implicit instantiations that need to be
2804   // instantiation within this scope.
2805   PerformPendingInstantiations(/*LocalOnly=*/true);
2806   Scope.Exit();
2807 
2808   if (Recursive) {
2809     // Define any pending vtables.
2810     DefineUsedVTables();
2811 
2812     // Instantiate any pending implicit instantiations found during the
2813     // instantiation of this template.
2814     PerformPendingInstantiations();
2815 
2816     // Restore the set of pending vtables.
2817     assert(VTableUses.empty() &&
2818            "VTableUses should be empty before it is discarded.");
2819     VTableUses.swap(SavedVTableUses);
2820 
2821     // Restore the set of pending implicit instantiations.
2822     assert(PendingInstantiations.empty() &&
2823            "PendingInstantiations should be empty before it is discarded.");
2824     PendingInstantiations.swap(SavedPendingInstantiations);
2825   }
2826 }
2827 
2828 /// \brief Instantiate the definition of the given variable from its
2829 /// template.
2830 ///
2831 /// \param PointOfInstantiation the point at which the instantiation was
2832 /// required. Note that this is not precisely a "point of instantiation"
2833 /// for the function, but it's close.
2834 ///
2835 /// \param Var the already-instantiated declaration of a static member
2836 /// variable of a class template specialization.
2837 ///
2838 /// \param Recursive if true, recursively instantiates any functions that
2839 /// are required by this instantiation.
2840 ///
2841 /// \param DefinitionRequired if true, then we are performing an explicit
2842 /// instantiation where an out-of-line definition of the member variable
2843 /// is required. Complain if there is no such definition.
InstantiateStaticDataMemberDefinition(SourceLocation PointOfInstantiation,VarDecl * Var,bool Recursive,bool DefinitionRequired)2844 void Sema::InstantiateStaticDataMemberDefinition(
2845                                           SourceLocation PointOfInstantiation,
2846                                                  VarDecl *Var,
2847                                                  bool Recursive,
2848                                                  bool DefinitionRequired) {
2849   if (Var->isInvalidDecl())
2850     return;
2851 
2852   // Find the out-of-line definition of this static data member.
2853   VarDecl *Def = Var->getInstantiatedFromStaticDataMember();
2854   assert(Def && "This data member was not instantiated from a template?");
2855   assert(Def->isStaticDataMember() && "Not a static data member?");
2856   Def = Def->getOutOfLineDefinition();
2857 
2858   if (!Def) {
2859     // We did not find an out-of-line definition of this static data member,
2860     // so we won't perform any instantiation. Rather, we rely on the user to
2861     // instantiate this definition (or provide a specialization for it) in
2862     // another translation unit.
2863     if (DefinitionRequired) {
2864       Def = Var->getInstantiatedFromStaticDataMember();
2865       Diag(PointOfInstantiation,
2866            diag::err_explicit_instantiation_undefined_member)
2867         << 2 << Var->getDeclName() << Var->getDeclContext();
2868       Diag(Def->getLocation(), diag::note_explicit_instantiation_here);
2869     } else if (Var->getTemplateSpecializationKind()
2870                  == TSK_ExplicitInstantiationDefinition) {
2871       PendingInstantiations.push_back(
2872         std::make_pair(Var, PointOfInstantiation));
2873     }
2874 
2875     return;
2876   }
2877 
2878   TemplateSpecializationKind TSK = Var->getTemplateSpecializationKind();
2879 
2880   // Never instantiate an explicit specialization.
2881   if (TSK == TSK_ExplicitSpecialization)
2882     return;
2883 
2884   // C++0x [temp.explicit]p9:
2885   //   Except for inline functions, other explicit instantiation declarations
2886   //   have the effect of suppressing the implicit instantiation of the entity
2887   //   to which they refer.
2888   if (TSK == TSK_ExplicitInstantiationDeclaration)
2889     return;
2890 
2891   Consumer.HandleCXXStaticMemberVarInstantiation(Var);
2892 
2893   // If we already have a definition, we're done.
2894   if (VarDecl *Def = Var->getDefinition()) {
2895     // We may be explicitly instantiating something we've already implicitly
2896     // instantiated.
2897     Def->setTemplateSpecializationKind(Var->getTemplateSpecializationKind(),
2898                                        PointOfInstantiation);
2899     return;
2900   }
2901 
2902   InstantiatingTemplate Inst(*this, PointOfInstantiation, Var);
2903   if (Inst)
2904     return;
2905 
2906   // If we're performing recursive template instantiation, create our own
2907   // queue of pending implicit instantiations that we will instantiate later,
2908   // while we're still within our own instantiation context.
2909   SmallVector<VTableUse, 16> SavedVTableUses;
2910   std::deque<PendingImplicitInstantiation> SavedPendingInstantiations;
2911   if (Recursive) {
2912     VTableUses.swap(SavedVTableUses);
2913     PendingInstantiations.swap(SavedPendingInstantiations);
2914   }
2915 
2916   // Enter the scope of this instantiation. We don't use
2917   // PushDeclContext because we don't have a scope.
2918   ContextRAII previousContext(*this, Var->getDeclContext());
2919   LocalInstantiationScope Local(*this);
2920 
2921   VarDecl *OldVar = Var;
2922   Var = cast_or_null<VarDecl>(SubstDecl(Def, Var->getDeclContext(),
2923                                         getTemplateInstantiationArgs(Var)));
2924 
2925   previousContext.pop();
2926 
2927   if (Var) {
2928     MemberSpecializationInfo *MSInfo = OldVar->getMemberSpecializationInfo();
2929     assert(MSInfo && "Missing member specialization information?");
2930     Var->setTemplateSpecializationKind(MSInfo->getTemplateSpecializationKind(),
2931                                        MSInfo->getPointOfInstantiation());
2932     DeclGroupRef DG(Var);
2933     Consumer.HandleTopLevelDecl(DG);
2934   }
2935   Local.Exit();
2936 
2937   if (Recursive) {
2938     // Define any newly required vtables.
2939     DefineUsedVTables();
2940 
2941     // Instantiate any pending implicit instantiations found during the
2942     // instantiation of this template.
2943     PerformPendingInstantiations();
2944 
2945     // Restore the set of pending vtables.
2946     assert(VTableUses.empty() &&
2947            "VTableUses should be empty before it is discarded, "
2948            "while instantiating static data member.");
2949     VTableUses.swap(SavedVTableUses);
2950 
2951     // Restore the set of pending implicit instantiations.
2952     assert(PendingInstantiations.empty() &&
2953            "PendingInstantiations should be empty before it is discarded, "
2954            "while instantiating static data member.");
2955     PendingInstantiations.swap(SavedPendingInstantiations);
2956   }
2957 }
2958 
2959 void
InstantiateMemInitializers(CXXConstructorDecl * New,const CXXConstructorDecl * Tmpl,const MultiLevelTemplateArgumentList & TemplateArgs)2960 Sema::InstantiateMemInitializers(CXXConstructorDecl *New,
2961                                  const CXXConstructorDecl *Tmpl,
2962                            const MultiLevelTemplateArgumentList &TemplateArgs) {
2963 
2964   SmallVector<CXXCtorInitializer*, 4> NewInits;
2965   bool AnyErrors = false;
2966 
2967   // Instantiate all the initializers.
2968   for (CXXConstructorDecl::init_const_iterator Inits = Tmpl->init_begin(),
2969                                             InitsEnd = Tmpl->init_end();
2970        Inits != InitsEnd; ++Inits) {
2971     CXXCtorInitializer *Init = *Inits;
2972 
2973     // Only instantiate written initializers, let Sema re-construct implicit
2974     // ones.
2975     if (!Init->isWritten())
2976       continue;
2977 
2978     SourceLocation EllipsisLoc;
2979 
2980     if (Init->isPackExpansion()) {
2981       // This is a pack expansion. We should expand it now.
2982       TypeLoc BaseTL = Init->getTypeSourceInfo()->getTypeLoc();
2983       SmallVector<UnexpandedParameterPack, 2> Unexpanded;
2984       collectUnexpandedParameterPacks(BaseTL, Unexpanded);
2985       bool ShouldExpand = false;
2986       bool RetainExpansion = false;
2987       llvm::Optional<unsigned> NumExpansions;
2988       if (CheckParameterPacksForExpansion(Init->getEllipsisLoc(),
2989                                           BaseTL.getSourceRange(),
2990                                           Unexpanded,
2991                                           TemplateArgs, ShouldExpand,
2992                                           RetainExpansion,
2993                                           NumExpansions)) {
2994         AnyErrors = true;
2995         New->setInvalidDecl();
2996         continue;
2997       }
2998       assert(ShouldExpand && "Partial instantiation of base initializer?");
2999 
3000       // Loop over all of the arguments in the argument pack(s),
3001       for (unsigned I = 0; I != *NumExpansions; ++I) {
3002         Sema::ArgumentPackSubstitutionIndexRAII SubstIndex(*this, I);
3003 
3004         // Instantiate the initializer.
3005         ExprResult TempInit = SubstInitializer(Init->getInit(), TemplateArgs,
3006                                                /*CXXDirectInit=*/true);
3007         if (TempInit.isInvalid()) {
3008           AnyErrors = true;
3009           break;
3010         }
3011 
3012         // Instantiate the base type.
3013         TypeSourceInfo *BaseTInfo = SubstType(Init->getTypeSourceInfo(),
3014                                               TemplateArgs,
3015                                               Init->getSourceLocation(),
3016                                               New->getDeclName());
3017         if (!BaseTInfo) {
3018           AnyErrors = true;
3019           break;
3020         }
3021 
3022         // Build the initializer.
3023         MemInitResult NewInit = BuildBaseInitializer(BaseTInfo->getType(),
3024                                                      BaseTInfo, TempInit.take(),
3025                                                      New->getParent(),
3026                                                      SourceLocation());
3027         if (NewInit.isInvalid()) {
3028           AnyErrors = true;
3029           break;
3030         }
3031 
3032         NewInits.push_back(NewInit.get());
3033       }
3034 
3035       continue;
3036     }
3037 
3038     // Instantiate the initializer.
3039     ExprResult TempInit = SubstInitializer(Init->getInit(), TemplateArgs,
3040                                            /*CXXDirectInit=*/true);
3041     if (TempInit.isInvalid()) {
3042       AnyErrors = true;
3043       continue;
3044     }
3045 
3046     MemInitResult NewInit;
3047     if (Init->isDelegatingInitializer() || Init->isBaseInitializer()) {
3048       TypeSourceInfo *TInfo = SubstType(Init->getTypeSourceInfo(),
3049                                         TemplateArgs,
3050                                         Init->getSourceLocation(),
3051                                         New->getDeclName());
3052       if (!TInfo) {
3053         AnyErrors = true;
3054         New->setInvalidDecl();
3055         continue;
3056       }
3057 
3058       if (Init->isBaseInitializer())
3059         NewInit = BuildBaseInitializer(TInfo->getType(), TInfo, TempInit.take(),
3060                                        New->getParent(), EllipsisLoc);
3061       else
3062         NewInit = BuildDelegatingInitializer(TInfo, TempInit.take(),
3063                                   cast<CXXRecordDecl>(CurContext->getParent()));
3064     } else if (Init->isMemberInitializer()) {
3065       FieldDecl *Member = cast_or_null<FieldDecl>(FindInstantiatedDecl(
3066                                                      Init->getMemberLocation(),
3067                                                      Init->getMember(),
3068                                                      TemplateArgs));
3069       if (!Member) {
3070         AnyErrors = true;
3071         New->setInvalidDecl();
3072         continue;
3073       }
3074 
3075       NewInit = BuildMemberInitializer(Member, TempInit.take(),
3076                                        Init->getSourceLocation());
3077     } else if (Init->isIndirectMemberInitializer()) {
3078       IndirectFieldDecl *IndirectMember =
3079          cast_or_null<IndirectFieldDecl>(FindInstantiatedDecl(
3080                                  Init->getMemberLocation(),
3081                                  Init->getIndirectMember(), TemplateArgs));
3082 
3083       if (!IndirectMember) {
3084         AnyErrors = true;
3085         New->setInvalidDecl();
3086         continue;
3087       }
3088 
3089       NewInit = BuildMemberInitializer(IndirectMember, TempInit.take(),
3090                                        Init->getSourceLocation());
3091     }
3092 
3093     if (NewInit.isInvalid()) {
3094       AnyErrors = true;
3095       New->setInvalidDecl();
3096     } else {
3097       NewInits.push_back(NewInit.get());
3098     }
3099   }
3100 
3101   // Assign all the initializers to the new constructor.
3102   ActOnMemInitializers(New,
3103                        /*FIXME: ColonLoc */
3104                        SourceLocation(),
3105                        NewInits.data(), NewInits.size(),
3106                        AnyErrors);
3107 }
3108 
SubstInitializer(Expr * Init,const MultiLevelTemplateArgumentList & TemplateArgs,bool CXXDirectInit)3109 ExprResult Sema::SubstInitializer(Expr *Init,
3110                           const MultiLevelTemplateArgumentList &TemplateArgs,
3111                           bool CXXDirectInit) {
3112   // Initializers are instantiated like expressions, except that various outer
3113   // layers are stripped.
3114   if (!Init)
3115     return Owned(Init);
3116 
3117   if (ExprWithCleanups *ExprTemp = dyn_cast<ExprWithCleanups>(Init))
3118     Init = ExprTemp->getSubExpr();
3119 
3120   while (CXXBindTemporaryExpr *Binder = dyn_cast<CXXBindTemporaryExpr>(Init))
3121     Init = Binder->getSubExpr();
3122 
3123   if (ImplicitCastExpr *ICE = dyn_cast<ImplicitCastExpr>(Init))
3124     Init = ICE->getSubExprAsWritten();
3125 
3126   // If this is a direct-initializer, we take apart CXXConstructExprs.
3127   // Everything else is passed through.
3128   CXXConstructExpr *Construct;
3129   if (!CXXDirectInit || !(Construct = dyn_cast<CXXConstructExpr>(Init)) ||
3130       isa<CXXTemporaryObjectExpr>(Construct))
3131     return SubstExpr(Init, TemplateArgs);
3132 
3133   SmallVector<Expr*, 8> NewArgs;
3134   if (SubstExprs(Construct->getArgs(), Construct->getNumArgs(), true,
3135                  TemplateArgs, NewArgs))
3136     return ExprError();
3137 
3138   // Treat an empty initializer like none.
3139   if (NewArgs.empty())
3140     return Owned((Expr*)0);
3141 
3142   // Build a ParenListExpr to represent anything else.
3143   // FIXME: Fake locations!
3144   SourceLocation Loc = PP.getLocForEndOfToken(Init->getLocStart());
3145   return ActOnParenListExpr(Loc, Loc, NewArgs);
3146 }
3147 
3148 // TODO: this could be templated if the various decl types used the
3149 // same method name.
isInstantiationOf(ClassTemplateDecl * Pattern,ClassTemplateDecl * Instance)3150 static bool isInstantiationOf(ClassTemplateDecl *Pattern,
3151                               ClassTemplateDecl *Instance) {
3152   Pattern = Pattern->getCanonicalDecl();
3153 
3154   do {
3155     Instance = Instance->getCanonicalDecl();
3156     if (Pattern == Instance) return true;
3157     Instance = Instance->getInstantiatedFromMemberTemplate();
3158   } while (Instance);
3159 
3160   return false;
3161 }
3162 
isInstantiationOf(FunctionTemplateDecl * Pattern,FunctionTemplateDecl * Instance)3163 static bool isInstantiationOf(FunctionTemplateDecl *Pattern,
3164                               FunctionTemplateDecl *Instance) {
3165   Pattern = Pattern->getCanonicalDecl();
3166 
3167   do {
3168     Instance = Instance->getCanonicalDecl();
3169     if (Pattern == Instance) return true;
3170     Instance = Instance->getInstantiatedFromMemberTemplate();
3171   } while (Instance);
3172 
3173   return false;
3174 }
3175 
3176 static bool
isInstantiationOf(ClassTemplatePartialSpecializationDecl * Pattern,ClassTemplatePartialSpecializationDecl * Instance)3177 isInstantiationOf(ClassTemplatePartialSpecializationDecl *Pattern,
3178                   ClassTemplatePartialSpecializationDecl *Instance) {
3179   Pattern
3180     = cast<ClassTemplatePartialSpecializationDecl>(Pattern->getCanonicalDecl());
3181   do {
3182     Instance = cast<ClassTemplatePartialSpecializationDecl>(
3183                                                 Instance->getCanonicalDecl());
3184     if (Pattern == Instance)
3185       return true;
3186     Instance = Instance->getInstantiatedFromMember();
3187   } while (Instance);
3188 
3189   return false;
3190 }
3191 
isInstantiationOf(CXXRecordDecl * Pattern,CXXRecordDecl * Instance)3192 static bool isInstantiationOf(CXXRecordDecl *Pattern,
3193                               CXXRecordDecl *Instance) {
3194   Pattern = Pattern->getCanonicalDecl();
3195 
3196   do {
3197     Instance = Instance->getCanonicalDecl();
3198     if (Pattern == Instance) return true;
3199     Instance = Instance->getInstantiatedFromMemberClass();
3200   } while (Instance);
3201 
3202   return false;
3203 }
3204 
isInstantiationOf(FunctionDecl * Pattern,FunctionDecl * Instance)3205 static bool isInstantiationOf(FunctionDecl *Pattern,
3206                               FunctionDecl *Instance) {
3207   Pattern = Pattern->getCanonicalDecl();
3208 
3209   do {
3210     Instance = Instance->getCanonicalDecl();
3211     if (Pattern == Instance) return true;
3212     Instance = Instance->getInstantiatedFromMemberFunction();
3213   } while (Instance);
3214 
3215   return false;
3216 }
3217 
isInstantiationOf(EnumDecl * Pattern,EnumDecl * Instance)3218 static bool isInstantiationOf(EnumDecl *Pattern,
3219                               EnumDecl *Instance) {
3220   Pattern = Pattern->getCanonicalDecl();
3221 
3222   do {
3223     Instance = Instance->getCanonicalDecl();
3224     if (Pattern == Instance) return true;
3225     Instance = Instance->getInstantiatedFromMemberEnum();
3226   } while (Instance);
3227 
3228   return false;
3229 }
3230 
isInstantiationOf(UsingShadowDecl * Pattern,UsingShadowDecl * Instance,ASTContext & C)3231 static bool isInstantiationOf(UsingShadowDecl *Pattern,
3232                               UsingShadowDecl *Instance,
3233                               ASTContext &C) {
3234   return C.getInstantiatedFromUsingShadowDecl(Instance) == Pattern;
3235 }
3236 
isInstantiationOf(UsingDecl * Pattern,UsingDecl * Instance,ASTContext & C)3237 static bool isInstantiationOf(UsingDecl *Pattern,
3238                               UsingDecl *Instance,
3239                               ASTContext &C) {
3240   return C.getInstantiatedFromUsingDecl(Instance) == Pattern;
3241 }
3242 
isInstantiationOf(UnresolvedUsingValueDecl * Pattern,UsingDecl * Instance,ASTContext & C)3243 static bool isInstantiationOf(UnresolvedUsingValueDecl *Pattern,
3244                               UsingDecl *Instance,
3245                               ASTContext &C) {
3246   return C.getInstantiatedFromUsingDecl(Instance) == Pattern;
3247 }
3248 
isInstantiationOf(UnresolvedUsingTypenameDecl * Pattern,UsingDecl * Instance,ASTContext & C)3249 static bool isInstantiationOf(UnresolvedUsingTypenameDecl *Pattern,
3250                               UsingDecl *Instance,
3251                               ASTContext &C) {
3252   return C.getInstantiatedFromUsingDecl(Instance) == Pattern;
3253 }
3254 
isInstantiationOfStaticDataMember(VarDecl * Pattern,VarDecl * Instance)3255 static bool isInstantiationOfStaticDataMember(VarDecl *Pattern,
3256                                               VarDecl *Instance) {
3257   assert(Instance->isStaticDataMember());
3258 
3259   Pattern = Pattern->getCanonicalDecl();
3260 
3261   do {
3262     Instance = Instance->getCanonicalDecl();
3263     if (Pattern == Instance) return true;
3264     Instance = Instance->getInstantiatedFromStaticDataMember();
3265   } while (Instance);
3266 
3267   return false;
3268 }
3269 
3270 // Other is the prospective instantiation
3271 // D is the prospective pattern
isInstantiationOf(ASTContext & Ctx,NamedDecl * D,Decl * Other)3272 static bool isInstantiationOf(ASTContext &Ctx, NamedDecl *D, Decl *Other) {
3273   if (D->getKind() != Other->getKind()) {
3274     if (UnresolvedUsingTypenameDecl *UUD
3275           = dyn_cast<UnresolvedUsingTypenameDecl>(D)) {
3276       if (UsingDecl *UD = dyn_cast<UsingDecl>(Other)) {
3277         return isInstantiationOf(UUD, UD, Ctx);
3278       }
3279     }
3280 
3281     if (UnresolvedUsingValueDecl *UUD
3282           = dyn_cast<UnresolvedUsingValueDecl>(D)) {
3283       if (UsingDecl *UD = dyn_cast<UsingDecl>(Other)) {
3284         return isInstantiationOf(UUD, UD, Ctx);
3285       }
3286     }
3287 
3288     return false;
3289   }
3290 
3291   if (CXXRecordDecl *Record = dyn_cast<CXXRecordDecl>(Other))
3292     return isInstantiationOf(cast<CXXRecordDecl>(D), Record);
3293 
3294   if (FunctionDecl *Function = dyn_cast<FunctionDecl>(Other))
3295     return isInstantiationOf(cast<FunctionDecl>(D), Function);
3296 
3297   if (EnumDecl *Enum = dyn_cast<EnumDecl>(Other))
3298     return isInstantiationOf(cast<EnumDecl>(D), Enum);
3299 
3300   if (VarDecl *Var = dyn_cast<VarDecl>(Other))
3301     if (Var->isStaticDataMember())
3302       return isInstantiationOfStaticDataMember(cast<VarDecl>(D), Var);
3303 
3304   if (ClassTemplateDecl *Temp = dyn_cast<ClassTemplateDecl>(Other))
3305     return isInstantiationOf(cast<ClassTemplateDecl>(D), Temp);
3306 
3307   if (FunctionTemplateDecl *Temp = dyn_cast<FunctionTemplateDecl>(Other))
3308     return isInstantiationOf(cast<FunctionTemplateDecl>(D), Temp);
3309 
3310   if (ClassTemplatePartialSpecializationDecl *PartialSpec
3311         = dyn_cast<ClassTemplatePartialSpecializationDecl>(Other))
3312     return isInstantiationOf(cast<ClassTemplatePartialSpecializationDecl>(D),
3313                              PartialSpec);
3314 
3315   if (FieldDecl *Field = dyn_cast<FieldDecl>(Other)) {
3316     if (!Field->getDeclName()) {
3317       // This is an unnamed field.
3318       return Ctx.getInstantiatedFromUnnamedFieldDecl(Field) ==
3319         cast<FieldDecl>(D);
3320     }
3321   }
3322 
3323   if (UsingDecl *Using = dyn_cast<UsingDecl>(Other))
3324     return isInstantiationOf(cast<UsingDecl>(D), Using, Ctx);
3325 
3326   if (UsingShadowDecl *Shadow = dyn_cast<UsingShadowDecl>(Other))
3327     return isInstantiationOf(cast<UsingShadowDecl>(D), Shadow, Ctx);
3328 
3329   return D->getDeclName() && isa<NamedDecl>(Other) &&
3330     D->getDeclName() == cast<NamedDecl>(Other)->getDeclName();
3331 }
3332 
3333 template<typename ForwardIterator>
findInstantiationOf(ASTContext & Ctx,NamedDecl * D,ForwardIterator first,ForwardIterator last)3334 static NamedDecl *findInstantiationOf(ASTContext &Ctx,
3335                                       NamedDecl *D,
3336                                       ForwardIterator first,
3337                                       ForwardIterator last) {
3338   for (; first != last; ++first)
3339     if (isInstantiationOf(Ctx, D, *first))
3340       return cast<NamedDecl>(*first);
3341 
3342   return 0;
3343 }
3344 
3345 /// \brief Finds the instantiation of the given declaration context
3346 /// within the current instantiation.
3347 ///
3348 /// \returns NULL if there was an error
FindInstantiatedContext(SourceLocation Loc,DeclContext * DC,const MultiLevelTemplateArgumentList & TemplateArgs)3349 DeclContext *Sema::FindInstantiatedContext(SourceLocation Loc, DeclContext* DC,
3350                           const MultiLevelTemplateArgumentList &TemplateArgs) {
3351   if (NamedDecl *D = dyn_cast<NamedDecl>(DC)) {
3352     Decl* ID = FindInstantiatedDecl(Loc, D, TemplateArgs);
3353     return cast_or_null<DeclContext>(ID);
3354   } else return DC;
3355 }
3356 
3357 /// \brief Find the instantiation of the given declaration within the
3358 /// current instantiation.
3359 ///
3360 /// This routine is intended to be used when \p D is a declaration
3361 /// referenced from within a template, that needs to mapped into the
3362 /// corresponding declaration within an instantiation. For example,
3363 /// given:
3364 ///
3365 /// \code
3366 /// template<typename T>
3367 /// struct X {
3368 ///   enum Kind {
3369 ///     KnownValue = sizeof(T)
3370 ///   };
3371 ///
3372 ///   bool getKind() const { return KnownValue; }
3373 /// };
3374 ///
3375 /// template struct X<int>;
3376 /// \endcode
3377 ///
3378 /// In the instantiation of X<int>::getKind(), we need to map the
3379 /// EnumConstantDecl for KnownValue (which refers to
3380 /// X<T>::\<Kind>\::KnownValue) to its instantiation
3381 /// (X<int>::\<Kind>\::KnownValue). InstantiateCurrentDeclRef() performs
3382 /// this mapping from within the instantiation of X<int>.
FindInstantiatedDecl(SourceLocation Loc,NamedDecl * D,const MultiLevelTemplateArgumentList & TemplateArgs)3383 NamedDecl *Sema::FindInstantiatedDecl(SourceLocation Loc, NamedDecl *D,
3384                           const MultiLevelTemplateArgumentList &TemplateArgs) {
3385   DeclContext *ParentDC = D->getDeclContext();
3386   if (isa<ParmVarDecl>(D) || isa<NonTypeTemplateParmDecl>(D) ||
3387       isa<TemplateTypeParmDecl>(D) || isa<TemplateTemplateParmDecl>(D) ||
3388       (ParentDC->isFunctionOrMethod() && ParentDC->isDependentContext()) ||
3389       (isa<CXXRecordDecl>(D) && cast<CXXRecordDecl>(D)->isLambda())) {
3390     // D is a local of some kind. Look into the map of local
3391     // declarations to their instantiations.
3392     typedef LocalInstantiationScope::DeclArgumentPack DeclArgumentPack;
3393     llvm::PointerUnion<Decl *, DeclArgumentPack *> *Found
3394       = CurrentInstantiationScope->findInstantiationOf(D);
3395 
3396     if (Found) {
3397       if (Decl *FD = Found->dyn_cast<Decl *>())
3398         return cast<NamedDecl>(FD);
3399 
3400       unsigned PackIdx = ArgumentPackSubstitutionIndex;
3401       return cast<NamedDecl>((*Found->get<DeclArgumentPack *>())[PackIdx]);
3402     }
3403 
3404     // If we didn't find the decl, then we must have a label decl that hasn't
3405     // been found yet.  Lazily instantiate it and return it now.
3406     assert(isa<LabelDecl>(D));
3407 
3408     Decl *Inst = SubstDecl(D, CurContext, TemplateArgs);
3409     assert(Inst && "Failed to instantiate label??");
3410 
3411     CurrentInstantiationScope->InstantiatedLocal(D, Inst);
3412     return cast<LabelDecl>(Inst);
3413   }
3414 
3415   if (CXXRecordDecl *Record = dyn_cast<CXXRecordDecl>(D)) {
3416     if (!Record->isDependentContext())
3417       return D;
3418 
3419     // Determine whether this record is the "templated" declaration describing
3420     // a class template or class template partial specialization.
3421     ClassTemplateDecl *ClassTemplate = Record->getDescribedClassTemplate();
3422     if (ClassTemplate)
3423       ClassTemplate = ClassTemplate->getCanonicalDecl();
3424     else if (ClassTemplatePartialSpecializationDecl *PartialSpec
3425                = dyn_cast<ClassTemplatePartialSpecializationDecl>(Record))
3426       ClassTemplate = PartialSpec->getSpecializedTemplate()->getCanonicalDecl();
3427 
3428     // Walk the current context to find either the record or an instantiation of
3429     // it.
3430     DeclContext *DC = CurContext;
3431     while (!DC->isFileContext()) {
3432       // If we're performing substitution while we're inside the template
3433       // definition, we'll find our own context. We're done.
3434       if (DC->Equals(Record))
3435         return Record;
3436 
3437       if (CXXRecordDecl *InstRecord = dyn_cast<CXXRecordDecl>(DC)) {
3438         // Check whether we're in the process of instantiating a class template
3439         // specialization of the template we're mapping.
3440         if (ClassTemplateSpecializationDecl *InstSpec
3441                       = dyn_cast<ClassTemplateSpecializationDecl>(InstRecord)){
3442           ClassTemplateDecl *SpecTemplate = InstSpec->getSpecializedTemplate();
3443           if (ClassTemplate && isInstantiationOf(ClassTemplate, SpecTemplate))
3444             return InstRecord;
3445         }
3446 
3447         // Check whether we're in the process of instantiating a member class.
3448         if (isInstantiationOf(Record, InstRecord))
3449           return InstRecord;
3450       }
3451 
3452 
3453       // Move to the outer template scope.
3454       if (FunctionDecl *FD = dyn_cast<FunctionDecl>(DC)) {
3455         if (FD->getFriendObjectKind() && FD->getDeclContext()->isFileContext()){
3456           DC = FD->getLexicalDeclContext();
3457           continue;
3458         }
3459       }
3460 
3461       DC = DC->getParent();
3462     }
3463 
3464     // Fall through to deal with other dependent record types (e.g.,
3465     // anonymous unions in class templates).
3466   }
3467 
3468   if (!ParentDC->isDependentContext())
3469     return D;
3470 
3471   ParentDC = FindInstantiatedContext(Loc, ParentDC, TemplateArgs);
3472   if (!ParentDC)
3473     return 0;
3474 
3475   if (ParentDC != D->getDeclContext()) {
3476     // We performed some kind of instantiation in the parent context,
3477     // so now we need to look into the instantiated parent context to
3478     // find the instantiation of the declaration D.
3479 
3480     // If our context used to be dependent, we may need to instantiate
3481     // it before performing lookup into that context.
3482     bool IsBeingInstantiated = false;
3483     if (CXXRecordDecl *Spec = dyn_cast<CXXRecordDecl>(ParentDC)) {
3484       if (!Spec->isDependentContext()) {
3485         QualType T = Context.getTypeDeclType(Spec);
3486         const RecordType *Tag = T->getAs<RecordType>();
3487         assert(Tag && "type of non-dependent record is not a RecordType");
3488         if (Tag->isBeingDefined())
3489           IsBeingInstantiated = true;
3490         if (!Tag->isBeingDefined() &&
3491             RequireCompleteType(Loc, T, diag::err_incomplete_type))
3492           return 0;
3493 
3494         ParentDC = Tag->getDecl();
3495       }
3496     }
3497 
3498     NamedDecl *Result = 0;
3499     if (D->getDeclName()) {
3500       DeclContext::lookup_result Found = ParentDC->lookup(D->getDeclName());
3501       Result = findInstantiationOf(Context, D, Found.first, Found.second);
3502     } else {
3503       // Since we don't have a name for the entity we're looking for,
3504       // our only option is to walk through all of the declarations to
3505       // find that name. This will occur in a few cases:
3506       //
3507       //   - anonymous struct/union within a template
3508       //   - unnamed class/struct/union/enum within a template
3509       //
3510       // FIXME: Find a better way to find these instantiations!
3511       Result = findInstantiationOf(Context, D,
3512                                    ParentDC->decls_begin(),
3513                                    ParentDC->decls_end());
3514     }
3515 
3516     if (!Result) {
3517       if (isa<UsingShadowDecl>(D)) {
3518         // UsingShadowDecls can instantiate to nothing because of using hiding.
3519       } else if (Diags.hasErrorOccurred()) {
3520         // We've already complained about something, so most likely this
3521         // declaration failed to instantiate. There's no point in complaining
3522         // further, since this is normal in invalid code.
3523       } else if (IsBeingInstantiated) {
3524         // The class in which this member exists is currently being
3525         // instantiated, and we haven't gotten around to instantiating this
3526         // member yet. This can happen when the code uses forward declarations
3527         // of member classes, and introduces ordering dependencies via
3528         // template instantiation.
3529         Diag(Loc, diag::err_member_not_yet_instantiated)
3530           << D->getDeclName()
3531           << Context.getTypeDeclType(cast<CXXRecordDecl>(ParentDC));
3532         Diag(D->getLocation(), diag::note_non_instantiated_member_here);
3533       } else if (EnumConstantDecl *ED = dyn_cast<EnumConstantDecl>(D)) {
3534         // This enumeration constant was found when the template was defined,
3535         // but can't be found in the instantiation. This can happen if an
3536         // unscoped enumeration member is explicitly specialized.
3537         EnumDecl *Enum = cast<EnumDecl>(ED->getLexicalDeclContext());
3538         EnumDecl *Spec = cast<EnumDecl>(FindInstantiatedDecl(Loc, Enum,
3539                                                              TemplateArgs));
3540         assert(Spec->getTemplateSpecializationKind() ==
3541                  TSK_ExplicitSpecialization);
3542         Diag(Loc, diag::err_enumerator_does_not_exist)
3543           << D->getDeclName()
3544           << Context.getTypeDeclType(cast<TypeDecl>(Spec->getDeclContext()));
3545         Diag(Spec->getLocation(), diag::note_enum_specialized_here)
3546           << Context.getTypeDeclType(Spec);
3547       } else {
3548         // We should have found something, but didn't.
3549         llvm_unreachable("Unable to find instantiation of declaration!");
3550       }
3551     }
3552 
3553     D = Result;
3554   }
3555 
3556   return D;
3557 }
3558 
3559 /// \brief Performs template instantiation for all implicit template
3560 /// instantiations we have seen until this point.
PerformPendingInstantiations(bool LocalOnly)3561 void Sema::PerformPendingInstantiations(bool LocalOnly) {
3562   // Load pending instantiations from the external source.
3563   if (!LocalOnly && ExternalSource) {
3564     SmallVector<PendingImplicitInstantiation, 4> Pending;
3565     ExternalSource->ReadPendingInstantiations(Pending);
3566     PendingInstantiations.insert(PendingInstantiations.begin(),
3567                                  Pending.begin(), Pending.end());
3568   }
3569 
3570   while (!PendingLocalImplicitInstantiations.empty() ||
3571          (!LocalOnly && !PendingInstantiations.empty())) {
3572     PendingImplicitInstantiation Inst;
3573 
3574     if (PendingLocalImplicitInstantiations.empty()) {
3575       Inst = PendingInstantiations.front();
3576       PendingInstantiations.pop_front();
3577     } else {
3578       Inst = PendingLocalImplicitInstantiations.front();
3579       PendingLocalImplicitInstantiations.pop_front();
3580     }
3581 
3582     // Instantiate function definitions
3583     if (FunctionDecl *Function = dyn_cast<FunctionDecl>(Inst.first)) {
3584       PrettyDeclStackTraceEntry CrashInfo(*this, Function, SourceLocation(),
3585                                           "instantiating function definition");
3586       bool DefinitionRequired = Function->getTemplateSpecializationKind() ==
3587                                 TSK_ExplicitInstantiationDefinition;
3588       InstantiateFunctionDefinition(/*FIXME:*/Inst.second, Function, true,
3589                                     DefinitionRequired);
3590       continue;
3591     }
3592 
3593     // Instantiate static data member definitions.
3594     VarDecl *Var = cast<VarDecl>(Inst.first);
3595     assert(Var->isStaticDataMember() && "Not a static data member?");
3596 
3597     // Don't try to instantiate declarations if the most recent redeclaration
3598     // is invalid.
3599     if (Var->getMostRecentDecl()->isInvalidDecl())
3600       continue;
3601 
3602     // Check if the most recent declaration has changed the specialization kind
3603     // and removed the need for implicit instantiation.
3604     switch (Var->getMostRecentDecl()->getTemplateSpecializationKind()) {
3605     case TSK_Undeclared:
3606       llvm_unreachable("Cannot instantitiate an undeclared specialization.");
3607     case TSK_ExplicitInstantiationDeclaration:
3608     case TSK_ExplicitSpecialization:
3609       continue;  // No longer need to instantiate this type.
3610     case TSK_ExplicitInstantiationDefinition:
3611       // We only need an instantiation if the pending instantiation *is* the
3612       // explicit instantiation.
3613       if (Var != Var->getMostRecentDecl()) continue;
3614     case TSK_ImplicitInstantiation:
3615       break;
3616     }
3617 
3618     PrettyDeclStackTraceEntry CrashInfo(*this, Var, Var->getLocation(),
3619                                         "instantiating static data member "
3620                                         "definition");
3621 
3622     bool DefinitionRequired = Var->getTemplateSpecializationKind() ==
3623                               TSK_ExplicitInstantiationDefinition;
3624     InstantiateStaticDataMemberDefinition(/*FIXME:*/Inst.second, Var, true,
3625                                           DefinitionRequired);
3626   }
3627 }
3628 
PerformDependentDiagnostics(const DeclContext * Pattern,const MultiLevelTemplateArgumentList & TemplateArgs)3629 void Sema::PerformDependentDiagnostics(const DeclContext *Pattern,
3630                        const MultiLevelTemplateArgumentList &TemplateArgs) {
3631   for (DeclContext::ddiag_iterator I = Pattern->ddiag_begin(),
3632          E = Pattern->ddiag_end(); I != E; ++I) {
3633     DependentDiagnostic *DD = *I;
3634 
3635     switch (DD->getKind()) {
3636     case DependentDiagnostic::Access:
3637       HandleDependentAccessCheck(*DD, TemplateArgs);
3638       break;
3639     }
3640   }
3641 }
3642