SemaTemplateInstantiateDecl.cpp revision a71f9d0a5e1f8cafdd23a17e292de22fdc8e99ff 
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
26using namespace clang;
27
28bool 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
44bool 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// FIXME: Is this still too simple?
61void Sema::InstantiateAttrs(const MultiLevelTemplateArgumentList &TemplateArgs,
62                            const Decl *Tmpl, Decl *New) {
63  for (AttrVec::const_iterator i = Tmpl->attr_begin(), e = Tmpl->attr_end();
64       i != e; ++i) {
65    const Attr *TmplAttr = *i;
66    // FIXME: This should be generalized to more than just the AlignedAttr.
67    if (const AlignedAttr *Aligned = dyn_cast<AlignedAttr>(TmplAttr)) {
68      if (Aligned->isAlignmentDependent()) {
69        // The alignment expression is not potentially evaluated.
70        EnterExpressionEvaluationContext Unevaluated(*this,
71                                                     Sema::Unevaluated);
72
73        if (Aligned->isAlignmentExpr()) {
74          ExprResult Result = SubstExpr(Aligned->getAlignmentExpr(),
75                                        TemplateArgs);
76          if (!Result.isInvalid())
77            AddAlignedAttr(Aligned->getLocation(), New, Result.takeAs<Expr>());
78        }
79        else {
80          TypeSourceInfo *Result = SubstType(Aligned->getAlignmentType(),
81                                             TemplateArgs,
82                                             Aligned->getLocation(),
83                                             DeclarationName());
84          if (Result)
85            AddAlignedAttr(Aligned->getLocation(), New, Result);
86        }
87        continue;
88      }
89    }
90
91    // FIXME: Is cloning correct for all attributes?
92    Attr *NewAttr = TmplAttr->clone(Context);
93    New->addAttr(NewAttr);
94  }
95}
96
97Decl *
98TemplateDeclInstantiator::VisitTranslationUnitDecl(TranslationUnitDecl *D) {
99  assert(false && "Translation units cannot be instantiated");
100  return D;
101}
102
103Decl *
104TemplateDeclInstantiator::VisitLabelDecl(LabelDecl *D) {
105  LabelDecl *Inst = LabelDecl::Create(SemaRef.Context, Owner, D->getLocation(),
106                                      D->getIdentifier());
107  Owner->addDecl(Inst);
108  return Inst;
109}
110
111Decl *
112TemplateDeclInstantiator::VisitNamespaceDecl(NamespaceDecl *D) {
113  assert(false && "Namespaces cannot be instantiated");
114  return D;
115}
116
117Decl *
118TemplateDeclInstantiator::VisitNamespaceAliasDecl(NamespaceAliasDecl *D) {
119  NamespaceAliasDecl *Inst
120    = NamespaceAliasDecl::Create(SemaRef.Context, Owner,
121                                 D->getNamespaceLoc(),
122                                 D->getAliasLoc(),
123                                 D->getIdentifier(),
124                                 D->getQualifierLoc(),
125                                 D->getTargetNameLoc(),
126                                 D->getNamespace());
127  Owner->addDecl(Inst);
128  return Inst;
129}
130
131Decl *TemplateDeclInstantiator::InstantiateTypedefNameDecl(TypedefNameDecl *D,
132                                                           bool IsTypeAlias) {
133  bool Invalid = false;
134  TypeSourceInfo *DI = D->getTypeSourceInfo();
135  if (DI->getType()->isInstantiationDependentType() ||
136      DI->getType()->isVariablyModifiedType()) {
137    DI = SemaRef.SubstType(DI, TemplateArgs,
138                           D->getLocation(), D->getDeclName());
139    if (!DI) {
140      Invalid = true;
141      DI = SemaRef.Context.getTrivialTypeSourceInfo(SemaRef.Context.IntTy);
142    }
143  } else {
144    SemaRef.MarkDeclarationsReferencedInType(D->getLocation(), DI->getType());
145  }
146
147  // Create the new typedef
148  TypedefNameDecl *Typedef;
149  if (IsTypeAlias)
150    Typedef = TypeAliasDecl::Create(SemaRef.Context, Owner, D->getLocStart(),
151                                    D->getLocation(), D->getIdentifier(), DI);
152  else
153    Typedef = TypedefDecl::Create(SemaRef.Context, Owner, D->getLocStart(),
154                                  D->getLocation(), D->getIdentifier(), DI);
155  if (Invalid)
156    Typedef->setInvalidDecl();
157
158  // If the old typedef was the name for linkage purposes of an anonymous
159  // tag decl, re-establish that relationship for the new typedef.
160  if (const TagType *oldTagType = D->getUnderlyingType()->getAs<TagType>()) {
161    TagDecl *oldTag = oldTagType->getDecl();
162    if (oldTag->getTypedefNameForAnonDecl() == D) {
163      TagDecl *newTag = DI->getType()->castAs<TagType>()->getDecl();
164      assert(!newTag->getIdentifier() && !newTag->getTypedefNameForAnonDecl());
165      newTag->setTypedefNameForAnonDecl(Typedef);
166    }
167  }
168
169  if (TypedefNameDecl *Prev = D->getPreviousDeclaration()) {
170    NamedDecl *InstPrev = SemaRef.FindInstantiatedDecl(D->getLocation(), Prev,
171                                                       TemplateArgs);
172    if (!InstPrev)
173      return 0;
174
175    Typedef->setPreviousDeclaration(cast<TypedefNameDecl>(InstPrev));
176  }
177
178  SemaRef.InstantiateAttrs(TemplateArgs, D, Typedef);
179
180  Typedef->setAccess(D->getAccess());
181
182  return Typedef;
183}
184
185Decl *TemplateDeclInstantiator::VisitTypedefDecl(TypedefDecl *D) {
186  Decl *Typedef = InstantiateTypedefNameDecl(D, /*IsTypeAlias=*/false);
187  Owner->addDecl(Typedef);
188  return Typedef;
189}
190
191Decl *TemplateDeclInstantiator::VisitTypeAliasDecl(TypeAliasDecl *D) {
192  Decl *Typedef = InstantiateTypedefNameDecl(D, /*IsTypeAlias=*/true);
193  Owner->addDecl(Typedef);
194  return Typedef;
195}
196
197Decl *
198TemplateDeclInstantiator::VisitTypeAliasTemplateDecl(TypeAliasTemplateDecl *D) {
199  // Create a local instantiation scope for this type alias template, which
200  // will contain the instantiations of the template parameters.
201  LocalInstantiationScope Scope(SemaRef);
202
203  TemplateParameterList *TempParams = D->getTemplateParameters();
204  TemplateParameterList *InstParams = SubstTemplateParams(TempParams);
205  if (!InstParams)
206    return 0;
207
208  TypeAliasDecl *Pattern = D->getTemplatedDecl();
209
210  TypeAliasTemplateDecl *PrevAliasTemplate = 0;
211  if (Pattern->getPreviousDeclaration()) {
212    DeclContext::lookup_result Found = Owner->lookup(Pattern->getDeclName());
213    if (Found.first != Found.second) {
214      PrevAliasTemplate = dyn_cast<TypeAliasTemplateDecl>(*Found.first);
215    }
216  }
217
218  TypeAliasDecl *AliasInst = cast_or_null<TypeAliasDecl>(
219    InstantiateTypedefNameDecl(Pattern, /*IsTypeAlias=*/true));
220  if (!AliasInst)
221    return 0;
222
223  TypeAliasTemplateDecl *Inst
224    = TypeAliasTemplateDecl::Create(SemaRef.Context, Owner, D->getLocation(),
225                                    D->getDeclName(), InstParams, AliasInst);
226  if (PrevAliasTemplate)
227    Inst->setPreviousDeclaration(PrevAliasTemplate);
228
229  Inst->setAccess(D->getAccess());
230
231  if (!PrevAliasTemplate)
232    Inst->setInstantiatedFromMemberTemplate(D);
233
234  Owner->addDecl(Inst);
235
236  return Inst;
237}
238
239/// \brief Instantiate an initializer, breaking it into separate
240/// initialization arguments.
241///
242/// \param Init The initializer to instantiate.
243///
244/// \param TemplateArgs Template arguments to be substituted into the
245/// initializer.
246///
247/// \param NewArgs Will be filled in with the instantiation arguments.
248///
249/// \returns true if an error occurred, false otherwise
250bool Sema::InstantiateInitializer(Expr *Init,
251                            const MultiLevelTemplateArgumentList &TemplateArgs,
252                                  SourceLocation &LParenLoc,
253                                  ASTOwningVector<Expr*> &NewArgs,
254                                  SourceLocation &RParenLoc) {
255  NewArgs.clear();
256  LParenLoc = SourceLocation();
257  RParenLoc = SourceLocation();
258
259  if (!Init)
260    return false;
261
262  if (ExprWithCleanups *ExprTemp = dyn_cast<ExprWithCleanups>(Init))
263    Init = ExprTemp->getSubExpr();
264
265  while (CXXBindTemporaryExpr *Binder = dyn_cast<CXXBindTemporaryExpr>(Init))
266    Init = Binder->getSubExpr();
267
268  if (ImplicitCastExpr *ICE = dyn_cast<ImplicitCastExpr>(Init))
269    Init = ICE->getSubExprAsWritten();
270
271  if (ParenListExpr *ParenList = dyn_cast<ParenListExpr>(Init)) {
272    LParenLoc = ParenList->getLParenLoc();
273    RParenLoc = ParenList->getRParenLoc();
274    return SubstExprs(ParenList->getExprs(), ParenList->getNumExprs(),
275                      true, TemplateArgs, NewArgs);
276  }
277
278  if (CXXConstructExpr *Construct = dyn_cast<CXXConstructExpr>(Init)) {
279    if (!isa<CXXTemporaryObjectExpr>(Construct)) {
280      if (SubstExprs(Construct->getArgs(), Construct->getNumArgs(), true,
281                     TemplateArgs, NewArgs))
282        return true;
283
284      // FIXME: Fake locations!
285      LParenLoc = PP.getLocForEndOfToken(Init->getLocStart());
286      RParenLoc = LParenLoc;
287      return false;
288    }
289  }
290
291  ExprResult Result = SubstExpr(Init, TemplateArgs);
292  if (Result.isInvalid())
293    return true;
294
295  NewArgs.push_back(Result.takeAs<Expr>());
296  return false;
297}
298
299Decl *TemplateDeclInstantiator::VisitVarDecl(VarDecl *D) {
300  // If this is the variable for an anonymous struct or union,
301  // instantiate the anonymous struct/union type first.
302  if (const RecordType *RecordTy = D->getType()->getAs<RecordType>())
303    if (RecordTy->getDecl()->isAnonymousStructOrUnion())
304      if (!VisitCXXRecordDecl(cast<CXXRecordDecl>(RecordTy->getDecl())))
305        return 0;
306
307  // Do substitution on the type of the declaration
308  TypeSourceInfo *DI = SemaRef.SubstType(D->getTypeSourceInfo(),
309                                         TemplateArgs,
310                                         D->getTypeSpecStartLoc(),
311                                         D->getDeclName());
312  if (!DI)
313    return 0;
314
315  if (DI->getType()->isFunctionType()) {
316    SemaRef.Diag(D->getLocation(), diag::err_variable_instantiates_to_function)
317      << D->isStaticDataMember() << DI->getType();
318    return 0;
319  }
320
321  // Build the instantiated declaration
322  VarDecl *Var = VarDecl::Create(SemaRef.Context, Owner,
323                                 D->getInnerLocStart(),
324                                 D->getLocation(), D->getIdentifier(),
325                                 DI->getType(), DI,
326                                 D->getStorageClass(),
327                                 D->getStorageClassAsWritten());
328  Var->setThreadSpecified(D->isThreadSpecified());
329  Var->setCXXDirectInitializer(D->hasCXXDirectInitializer());
330  Var->setCXXForRangeDecl(D->isCXXForRangeDecl());
331
332  // Substitute the nested name specifier, if any.
333  if (SubstQualifier(D, Var))
334    return 0;
335
336  // If we are instantiating a static data member defined
337  // out-of-line, the instantiation will have the same lexical
338  // context (which will be a namespace scope) as the template.
339  if (D->isOutOfLine())
340    Var->setLexicalDeclContext(D->getLexicalDeclContext());
341
342  Var->setAccess(D->getAccess());
343
344  if (!D->isStaticDataMember()) {
345    Var->setUsed(D->isUsed(false));
346    Var->setReferenced(D->isReferenced());
347  }
348
349  // FIXME: In theory, we could have a previous declaration for variables that
350  // are not static data members.
351  bool Redeclaration = false;
352  // FIXME: having to fake up a LookupResult is dumb.
353  LookupResult Previous(SemaRef, Var->getDeclName(), Var->getLocation(),
354                        Sema::LookupOrdinaryName, Sema::ForRedeclaration);
355  if (D->isStaticDataMember())
356    SemaRef.LookupQualifiedName(Previous, Owner, false);
357  SemaRef.CheckVariableDeclaration(Var, Previous, Redeclaration);
358
359  if (D->isOutOfLine()) {
360    if (!D->isStaticDataMember())
361      D->getLexicalDeclContext()->addDecl(Var);
362    Owner->makeDeclVisibleInContext(Var);
363  } else {
364    Owner->addDecl(Var);
365    if (Owner->isFunctionOrMethod())
366      SemaRef.CurrentInstantiationScope->InstantiatedLocal(D, Var);
367  }
368  SemaRef.InstantiateAttrs(TemplateArgs, D, Var);
369
370  // Link instantiations of static data members back to the template from
371  // which they were instantiated.
372  if (Var->isStaticDataMember())
373    SemaRef.Context.setInstantiatedFromStaticDataMember(Var, D,
374                                                     TSK_ImplicitInstantiation);
375
376  if (Var->getAnyInitializer()) {
377    // We already have an initializer in the class.
378  } else if (D->getInit()) {
379    if (Var->isStaticDataMember() && !D->isOutOfLine())
380      SemaRef.PushExpressionEvaluationContext(Sema::Unevaluated);
381    else
382      SemaRef.PushExpressionEvaluationContext(Sema::PotentiallyEvaluated);
383
384    // Instantiate the initializer.
385    SourceLocation LParenLoc, RParenLoc;
386    ASTOwningVector<Expr*> InitArgs(SemaRef);
387    if (!SemaRef.InstantiateInitializer(D->getInit(), TemplateArgs, LParenLoc,
388                                        InitArgs, RParenLoc)) {
389      bool TypeMayContainAuto = true;
390      // Attach the initializer to the declaration, if we have one.
391      if (InitArgs.size() == 0)
392        SemaRef.ActOnUninitializedDecl(Var, TypeMayContainAuto);
393      else if (D->hasCXXDirectInitializer()) {
394        // Add the direct initializer to the declaration.
395        SemaRef.AddCXXDirectInitializerToDecl(Var,
396                                              LParenLoc,
397                                              move_arg(InitArgs),
398                                              RParenLoc,
399                                              TypeMayContainAuto);
400      } else {
401        assert(InitArgs.size() == 1);
402        Expr *Init = InitArgs.take()[0];
403        SemaRef.AddInitializerToDecl(Var, Init, false, TypeMayContainAuto);
404      }
405    } else {
406      // FIXME: Not too happy about invalidating the declaration
407      // because of a bogus initializer.
408      Var->setInvalidDecl();
409    }
410
411    SemaRef.PopExpressionEvaluationContext();
412  } else if ((!Var->isStaticDataMember() || Var->isOutOfLine()) &&
413             !Var->isCXXForRangeDecl())
414    SemaRef.ActOnUninitializedDecl(Var, false);
415
416  // Diagnose unused local variables with dependent types, where the diagnostic
417  // will have been deferred.
418  if (!Var->isInvalidDecl() && Owner->isFunctionOrMethod() && !Var->isUsed() &&
419      D->getType()->isDependentType())
420    SemaRef.DiagnoseUnusedDecl(Var);
421
422  return Var;
423}
424
425Decl *TemplateDeclInstantiator::VisitAccessSpecDecl(AccessSpecDecl *D) {
426  AccessSpecDecl* AD
427    = AccessSpecDecl::Create(SemaRef.Context, D->getAccess(), Owner,
428                             D->getAccessSpecifierLoc(), D->getColonLoc());
429  Owner->addHiddenDecl(AD);
430  return AD;
431}
432
433Decl *TemplateDeclInstantiator::VisitFieldDecl(FieldDecl *D) {
434  bool Invalid = false;
435  TypeSourceInfo *DI = D->getTypeSourceInfo();
436  if (DI->getType()->isInstantiationDependentType() ||
437      DI->getType()->isVariablyModifiedType())  {
438    DI = SemaRef.SubstType(DI, TemplateArgs,
439                           D->getLocation(), D->getDeclName());
440    if (!DI) {
441      DI = D->getTypeSourceInfo();
442      Invalid = true;
443    } else if (DI->getType()->isFunctionType()) {
444      // C++ [temp.arg.type]p3:
445      //   If a declaration acquires a function type through a type
446      //   dependent on a template-parameter and this causes a
447      //   declaration that does not use the syntactic form of a
448      //   function declarator to have function type, the program is
449      //   ill-formed.
450      SemaRef.Diag(D->getLocation(), diag::err_field_instantiates_to_function)
451        << DI->getType();
452      Invalid = true;
453    }
454  } else {
455    SemaRef.MarkDeclarationsReferencedInType(D->getLocation(), DI->getType());
456  }
457
458  Expr *BitWidth = D->getBitWidth();
459  if (Invalid)
460    BitWidth = 0;
461  else if (BitWidth) {
462    // The bit-width expression is not potentially evaluated.
463    EnterExpressionEvaluationContext Unevaluated(SemaRef, Sema::Unevaluated);
464
465    ExprResult InstantiatedBitWidth
466      = SemaRef.SubstExpr(BitWidth, TemplateArgs);
467    if (InstantiatedBitWidth.isInvalid()) {
468      Invalid = true;
469      BitWidth = 0;
470    } else
471      BitWidth = InstantiatedBitWidth.takeAs<Expr>();
472  }
473
474  FieldDecl *Field = SemaRef.CheckFieldDecl(D->getDeclName(),
475                                            DI->getType(), DI,
476                                            cast<RecordDecl>(Owner),
477                                            D->getLocation(),
478                                            D->isMutable(),
479                                            BitWidth,
480                                            D->hasInClassInitializer(),
481                                            D->getTypeSpecStartLoc(),
482                                            D->getAccess(),
483                                            0);
484  if (!Field) {
485    cast<Decl>(Owner)->setInvalidDecl();
486    return 0;
487  }
488
489  SemaRef.InstantiateAttrs(TemplateArgs, D, Field);
490
491  if (Invalid)
492    Field->setInvalidDecl();
493
494  if (!Field->getDeclName()) {
495    // Keep track of where this decl came from.
496    SemaRef.Context.setInstantiatedFromUnnamedFieldDecl(Field, D);
497  }
498  if (CXXRecordDecl *Parent= dyn_cast<CXXRecordDecl>(Field->getDeclContext())) {
499    if (Parent->isAnonymousStructOrUnion() &&
500        Parent->getRedeclContext()->isFunctionOrMethod())
501      SemaRef.CurrentInstantiationScope->InstantiatedLocal(D, Field);
502  }
503
504  Field->setImplicit(D->isImplicit());
505  Field->setAccess(D->getAccess());
506  Owner->addDecl(Field);
507
508  return Field;
509}
510
511Decl *TemplateDeclInstantiator::VisitIndirectFieldDecl(IndirectFieldDecl *D) {
512  NamedDecl **NamedChain =
513    new (SemaRef.Context)NamedDecl*[D->getChainingSize()];
514
515  int i = 0;
516  for (IndirectFieldDecl::chain_iterator PI =
517       D->chain_begin(), PE = D->chain_end();
518       PI != PE; ++PI) {
519    NamedDecl *Next = SemaRef.FindInstantiatedDecl(D->getLocation(), *PI,
520                                              TemplateArgs);
521    if (!Next)
522      return 0;
523
524    NamedChain[i++] = Next;
525  }
526
527  QualType T = cast<FieldDecl>(NamedChain[i-1])->getType();
528  IndirectFieldDecl* IndirectField
529    = IndirectFieldDecl::Create(SemaRef.Context, Owner, D->getLocation(),
530                                D->getIdentifier(), T,
531                                NamedChain, D->getChainingSize());
532
533
534  IndirectField->setImplicit(D->isImplicit());
535  IndirectField->setAccess(D->getAccess());
536  Owner->addDecl(IndirectField);
537  return IndirectField;
538}
539
540Decl *TemplateDeclInstantiator::VisitFriendDecl(FriendDecl *D) {
541  // Handle friend type expressions by simply substituting template
542  // parameters into the pattern type and checking the result.
543  if (TypeSourceInfo *Ty = D->getFriendType()) {
544    TypeSourceInfo *InstTy;
545    // If this is an unsupported friend, don't bother substituting template
546    // arguments into it. The actual type referred to won't be used by any
547    // parts of Clang, and may not be valid for instantiating. Just use the
548    // same info for the instantiated friend.
549    if (D->isUnsupportedFriend()) {
550      InstTy = Ty;
551    } else {
552      InstTy = SemaRef.SubstType(Ty, TemplateArgs,
553                                 D->getLocation(), DeclarationName());
554    }
555    if (!InstTy)
556      return 0;
557
558    FriendDecl *FD = SemaRef.CheckFriendTypeDecl(D->getFriendLoc(), InstTy);
559    if (!FD)
560      return 0;
561
562    FD->setAccess(AS_public);
563    FD->setUnsupportedFriend(D->isUnsupportedFriend());
564    Owner->addDecl(FD);
565    return FD;
566  }
567
568  NamedDecl *ND = D->getFriendDecl();
569  assert(ND && "friend decl must be a decl or a type!");
570
571  // All of the Visit implementations for the various potential friend
572  // declarations have to be carefully written to work for friend
573  // objects, with the most important detail being that the target
574  // decl should almost certainly not be placed in Owner.
575  Decl *NewND = Visit(ND);
576  if (!NewND) return 0;
577
578  FriendDecl *FD =
579    FriendDecl::Create(SemaRef.Context, Owner, D->getLocation(),
580                       cast<NamedDecl>(NewND), D->getFriendLoc());
581  FD->setAccess(AS_public);
582  FD->setUnsupportedFriend(D->isUnsupportedFriend());
583  Owner->addDecl(FD);
584  return FD;
585}
586
587Decl *TemplateDeclInstantiator::VisitStaticAssertDecl(StaticAssertDecl *D) {
588  Expr *AssertExpr = D->getAssertExpr();
589
590  // The expression in a static assertion is not potentially evaluated.
591  EnterExpressionEvaluationContext Unevaluated(SemaRef, Sema::Unevaluated);
592
593  ExprResult InstantiatedAssertExpr
594    = SemaRef.SubstExpr(AssertExpr, TemplateArgs);
595  if (InstantiatedAssertExpr.isInvalid())
596    return 0;
597
598  ExprResult Message(D->getMessage());
599  D->getMessage();
600  return SemaRef.ActOnStaticAssertDeclaration(D->getLocation(),
601                                              InstantiatedAssertExpr.get(),
602                                              Message.get(),
603                                              D->getRParenLoc());
604}
605
606Decl *TemplateDeclInstantiator::VisitEnumDecl(EnumDecl *D) {
607  EnumDecl *Enum = EnumDecl::Create(SemaRef.Context, Owner, D->getLocStart(),
608                                    D->getLocation(), D->getIdentifier(),
609                                    /*PrevDecl=*/0, D->isScoped(),
610                                    D->isScopedUsingClassTag(), D->isFixed());
611  if (D->isFixed()) {
612    if (TypeSourceInfo* TI = D->getIntegerTypeSourceInfo()) {
613      // If we have type source information for the underlying type, it means it
614      // has been explicitly set by the user. Perform substitution on it before
615      // moving on.
616      SourceLocation UnderlyingLoc = TI->getTypeLoc().getBeginLoc();
617      Enum->setIntegerTypeSourceInfo(SemaRef.SubstType(TI,
618                                                       TemplateArgs,
619                                                       UnderlyingLoc,
620                                                       DeclarationName()));
621
622      if (!Enum->getIntegerTypeSourceInfo())
623        Enum->setIntegerType(SemaRef.Context.IntTy);
624    }
625    else {
626      assert(!D->getIntegerType()->isDependentType()
627             && "Dependent type without type source info");
628      Enum->setIntegerType(D->getIntegerType());
629    }
630  }
631
632  SemaRef.InstantiateAttrs(TemplateArgs, D, Enum);
633
634  Enum->setInstantiationOfMemberEnum(D);
635  Enum->setAccess(D->getAccess());
636  if (SubstQualifier(D, Enum)) return 0;
637  Owner->addDecl(Enum);
638  Enum->startDefinition();
639
640  if (D->getDeclContext()->isFunctionOrMethod())
641    SemaRef.CurrentInstantiationScope->InstantiatedLocal(D, Enum);
642
643  SmallVector<Decl*, 4> Enumerators;
644
645  EnumConstantDecl *LastEnumConst = 0;
646  for (EnumDecl::enumerator_iterator EC = D->enumerator_begin(),
647         ECEnd = D->enumerator_end();
648       EC != ECEnd; ++EC) {
649    // The specified value for the enumerator.
650    ExprResult Value = SemaRef.Owned((Expr *)0);
651    if (Expr *UninstValue = EC->getInitExpr()) {
652      // The enumerator's value expression is not potentially evaluated.
653      EnterExpressionEvaluationContext Unevaluated(SemaRef,
654                                                   Sema::Unevaluated);
655
656      Value = SemaRef.SubstExpr(UninstValue, TemplateArgs);
657    }
658
659    // Drop the initial value and continue.
660    bool isInvalid = false;
661    if (Value.isInvalid()) {
662      Value = SemaRef.Owned((Expr *)0);
663      isInvalid = true;
664    }
665
666    EnumConstantDecl *EnumConst
667      = SemaRef.CheckEnumConstant(Enum, LastEnumConst,
668                                  EC->getLocation(), EC->getIdentifier(),
669                                  Value.get());
670
671    if (isInvalid) {
672      if (EnumConst)
673        EnumConst->setInvalidDecl();
674      Enum->setInvalidDecl();
675    }
676
677    if (EnumConst) {
678      SemaRef.InstantiateAttrs(TemplateArgs, *EC, EnumConst);
679
680      EnumConst->setAccess(Enum->getAccess());
681      Enum->addDecl(EnumConst);
682      Enumerators.push_back(EnumConst);
683      LastEnumConst = EnumConst;
684
685      if (D->getDeclContext()->isFunctionOrMethod()) {
686        // If the enumeration is within a function or method, record the enum
687        // constant as a local.
688        SemaRef.CurrentInstantiationScope->InstantiatedLocal(*EC, EnumConst);
689      }
690    }
691  }
692
693  // FIXME: Fixup LBraceLoc and RBraceLoc
694  // FIXME: Empty Scope and AttributeList (required to handle attribute packed).
695  SemaRef.ActOnEnumBody(Enum->getLocation(), SourceLocation(), SourceLocation(),
696                        Enum,
697                        Enumerators.data(), Enumerators.size(),
698                        0, 0);
699
700  return Enum;
701}
702
703Decl *TemplateDeclInstantiator::VisitEnumConstantDecl(EnumConstantDecl *D) {
704  assert(false && "EnumConstantDecls can only occur within EnumDecls.");
705  return 0;
706}
707
708Decl *TemplateDeclInstantiator::VisitClassTemplateDecl(ClassTemplateDecl *D) {
709  bool isFriend = (D->getFriendObjectKind() != Decl::FOK_None);
710
711  // Create a local instantiation scope for this class template, which
712  // will contain the instantiations of the template parameters.
713  LocalInstantiationScope Scope(SemaRef);
714  TemplateParameterList *TempParams = D->getTemplateParameters();
715  TemplateParameterList *InstParams = SubstTemplateParams(TempParams);
716  if (!InstParams)
717    return NULL;
718
719  CXXRecordDecl *Pattern = D->getTemplatedDecl();
720
721  // Instantiate the qualifier.  We have to do this first in case
722  // we're a friend declaration, because if we are then we need to put
723  // the new declaration in the appropriate context.
724  NestedNameSpecifierLoc QualifierLoc = Pattern->getQualifierLoc();
725  if (QualifierLoc) {
726    QualifierLoc = SemaRef.SubstNestedNameSpecifierLoc(QualifierLoc,
727                                                       TemplateArgs);
728    if (!QualifierLoc)
729      return 0;
730  }
731
732  CXXRecordDecl *PrevDecl = 0;
733  ClassTemplateDecl *PrevClassTemplate = 0;
734
735  if (!isFriend && Pattern->getPreviousDeclaration()) {
736    DeclContext::lookup_result Found = Owner->lookup(Pattern->getDeclName());
737    if (Found.first != Found.second) {
738      PrevClassTemplate = dyn_cast<ClassTemplateDecl>(*Found.first);
739      if (PrevClassTemplate)
740        PrevDecl = PrevClassTemplate->getTemplatedDecl();
741    }
742  }
743
744  // If this isn't a friend, then it's a member template, in which
745  // case we just want to build the instantiation in the
746  // specialization.  If it is a friend, we want to build it in
747  // the appropriate context.
748  DeclContext *DC = Owner;
749  if (isFriend) {
750    if (QualifierLoc) {
751      CXXScopeSpec SS;
752      SS.Adopt(QualifierLoc);
753      DC = SemaRef.computeDeclContext(SS);
754      if (!DC) return 0;
755    } else {
756      DC = SemaRef.FindInstantiatedContext(Pattern->getLocation(),
757                                           Pattern->getDeclContext(),
758                                           TemplateArgs);
759    }
760
761    // Look for a previous declaration of the template in the owning
762    // context.
763    LookupResult R(SemaRef, Pattern->getDeclName(), Pattern->getLocation(),
764                   Sema::LookupOrdinaryName, Sema::ForRedeclaration);
765    SemaRef.LookupQualifiedName(R, DC);
766
767    if (R.isSingleResult()) {
768      PrevClassTemplate = R.getAsSingle<ClassTemplateDecl>();
769      if (PrevClassTemplate)
770        PrevDecl = PrevClassTemplate->getTemplatedDecl();
771    }
772
773    if (!PrevClassTemplate && QualifierLoc) {
774      SemaRef.Diag(Pattern->getLocation(), diag::err_not_tag_in_scope)
775        << D->getTemplatedDecl()->getTagKind() << Pattern->getDeclName() << DC
776        << QualifierLoc.getSourceRange();
777      return 0;
778    }
779
780    bool AdoptedPreviousTemplateParams = false;
781    if (PrevClassTemplate) {
782      bool Complain = true;
783
784      // HACK: libstdc++ 4.2.1 contains an ill-formed friend class
785      // template for struct std::tr1::__detail::_Map_base, where the
786      // template parameters of the friend declaration don't match the
787      // template parameters of the original declaration. In this one
788      // case, we don't complain about the ill-formed friend
789      // declaration.
790      if (isFriend && Pattern->getIdentifier() &&
791          Pattern->getIdentifier()->isStr("_Map_base") &&
792          DC->isNamespace() &&
793          cast<NamespaceDecl>(DC)->getIdentifier() &&
794          cast<NamespaceDecl>(DC)->getIdentifier()->isStr("__detail")) {
795        DeclContext *DCParent = DC->getParent();
796        if (DCParent->isNamespace() &&
797            cast<NamespaceDecl>(DCParent)->getIdentifier() &&
798            cast<NamespaceDecl>(DCParent)->getIdentifier()->isStr("tr1")) {
799          DeclContext *DCParent2 = DCParent->getParent();
800          if (DCParent2->isNamespace() &&
801              cast<NamespaceDecl>(DCParent2)->getIdentifier() &&
802              cast<NamespaceDecl>(DCParent2)->getIdentifier()->isStr("std") &&
803              DCParent2->getParent()->isTranslationUnit())
804            Complain = false;
805        }
806      }
807
808      TemplateParameterList *PrevParams
809        = PrevClassTemplate->getTemplateParameters();
810
811      // Make sure the parameter lists match.
812      if (!SemaRef.TemplateParameterListsAreEqual(InstParams, PrevParams,
813                                                  Complain,
814                                                  Sema::TPL_TemplateMatch)) {
815        if (Complain)
816          return 0;
817
818        AdoptedPreviousTemplateParams = true;
819        InstParams = PrevParams;
820      }
821
822      // Do some additional validation, then merge default arguments
823      // from the existing declarations.
824      if (!AdoptedPreviousTemplateParams &&
825          SemaRef.CheckTemplateParameterList(InstParams, PrevParams,
826                                             Sema::TPC_ClassTemplate))
827        return 0;
828    }
829  }
830
831  CXXRecordDecl *RecordInst
832    = CXXRecordDecl::Create(SemaRef.Context, Pattern->getTagKind(), DC,
833                            Pattern->getLocStart(), Pattern->getLocation(),
834                            Pattern->getIdentifier(), PrevDecl,
835                            /*DelayTypeCreation=*/true);
836
837  if (QualifierLoc)
838    RecordInst->setQualifierInfo(QualifierLoc);
839
840  ClassTemplateDecl *Inst
841    = ClassTemplateDecl::Create(SemaRef.Context, DC, D->getLocation(),
842                                D->getIdentifier(), InstParams, RecordInst,
843                                PrevClassTemplate);
844  RecordInst->setDescribedClassTemplate(Inst);
845
846  if (isFriend) {
847    if (PrevClassTemplate)
848      Inst->setAccess(PrevClassTemplate->getAccess());
849    else
850      Inst->setAccess(D->getAccess());
851
852    Inst->setObjectOfFriendDecl(PrevClassTemplate != 0);
853    // TODO: do we want to track the instantiation progeny of this
854    // friend target decl?
855  } else {
856    Inst->setAccess(D->getAccess());
857    if (!PrevClassTemplate)
858      Inst->setInstantiatedFromMemberTemplate(D);
859  }
860
861  // Trigger creation of the type for the instantiation.
862  SemaRef.Context.getInjectedClassNameType(RecordInst,
863                                    Inst->getInjectedClassNameSpecialization());
864
865  // Finish handling of friends.
866  if (isFriend) {
867    DC->makeDeclVisibleInContext(Inst, /*Recoverable*/ false);
868    return Inst;
869  }
870
871  Owner->addDecl(Inst);
872
873  if (!PrevClassTemplate) {
874    // Queue up any out-of-line partial specializations of this member
875    // class template; the client will force their instantiation once
876    // the enclosing class has been instantiated.
877    SmallVector<ClassTemplatePartialSpecializationDecl *, 4> PartialSpecs;
878    D->getPartialSpecializations(PartialSpecs);
879    for (unsigned I = 0, N = PartialSpecs.size(); I != N; ++I)
880      if (PartialSpecs[I]->isOutOfLine())
881        OutOfLinePartialSpecs.push_back(std::make_pair(Inst, PartialSpecs[I]));
882  }
883
884  return Inst;
885}
886
887Decl *
888TemplateDeclInstantiator::VisitClassTemplatePartialSpecializationDecl(
889                                   ClassTemplatePartialSpecializationDecl *D) {
890  ClassTemplateDecl *ClassTemplate = D->getSpecializedTemplate();
891
892  // Lookup the already-instantiated declaration in the instantiation
893  // of the class template and return that.
894  DeclContext::lookup_result Found
895    = Owner->lookup(ClassTemplate->getDeclName());
896  if (Found.first == Found.second)
897    return 0;
898
899  ClassTemplateDecl *InstClassTemplate
900    = dyn_cast<ClassTemplateDecl>(*Found.first);
901  if (!InstClassTemplate)
902    return 0;
903
904  if (ClassTemplatePartialSpecializationDecl *Result
905        = InstClassTemplate->findPartialSpecInstantiatedFromMember(D))
906    return Result;
907
908  return InstantiateClassTemplatePartialSpecialization(InstClassTemplate, D);
909}
910
911Decl *
912TemplateDeclInstantiator::VisitFunctionTemplateDecl(FunctionTemplateDecl *D) {
913  // Create a local instantiation scope for this function template, which
914  // will contain the instantiations of the template parameters and then get
915  // merged with the local instantiation scope for the function template
916  // itself.
917  LocalInstantiationScope Scope(SemaRef);
918
919  TemplateParameterList *TempParams = D->getTemplateParameters();
920  TemplateParameterList *InstParams = SubstTemplateParams(TempParams);
921  if (!InstParams)
922    return NULL;
923
924  FunctionDecl *Instantiated = 0;
925  if (CXXMethodDecl *DMethod = dyn_cast<CXXMethodDecl>(D->getTemplatedDecl()))
926    Instantiated = cast_or_null<FunctionDecl>(VisitCXXMethodDecl(DMethod,
927                                                                 InstParams));
928  else
929    Instantiated = cast_or_null<FunctionDecl>(VisitFunctionDecl(
930                                                          D->getTemplatedDecl(),
931                                                                InstParams));
932
933  if (!Instantiated)
934    return 0;
935
936  Instantiated->setAccess(D->getAccess());
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
958  return InstTemplate;
959}
960
961Decl *TemplateDeclInstantiator::VisitCXXRecordDecl(CXXRecordDecl *D) {
962  CXXRecordDecl *PrevDecl = 0;
963  if (D->isInjectedClassName())
964    PrevDecl = cast<CXXRecordDecl>(Owner);
965  else if (D->getPreviousDeclaration()) {
966    NamedDecl *Prev = SemaRef.FindInstantiatedDecl(D->getLocation(),
967                                                   D->getPreviousDeclaration(),
968                                                   TemplateArgs);
969    if (!Prev) return 0;
970    PrevDecl = cast<CXXRecordDecl>(Prev);
971  }
972
973  CXXRecordDecl *Record
974    = CXXRecordDecl::Create(SemaRef.Context, D->getTagKind(), Owner,
975                            D->getLocStart(), D->getLocation(),
976                            D->getIdentifier(), PrevDecl);
977
978  // Substitute the nested name specifier, if any.
979  if (SubstQualifier(D, Record))
980    return 0;
981
982  Record->setImplicit(D->isImplicit());
983  // FIXME: Check against AS_none is an ugly hack to work around the issue that
984  // the tag decls introduced by friend class declarations don't have an access
985  // specifier. Remove once this area of the code gets sorted out.
986  if (D->getAccess() != AS_none)
987    Record->setAccess(D->getAccess());
988  if (!D->isInjectedClassName())
989    Record->setInstantiationOfMemberClass(D, TSK_ImplicitInstantiation);
990
991  // If the original function was part of a friend declaration,
992  // inherit its namespace state.
993  if (Decl::FriendObjectKind FOK = D->getFriendObjectKind())
994    Record->setObjectOfFriendDecl(FOK == Decl::FOK_Declared);
995
996  // Make sure that anonymous structs and unions are recorded.
997  if (D->isAnonymousStructOrUnion()) {
998    Record->setAnonymousStructOrUnion(true);
999    if (Record->getDeclContext()->getRedeclContext()->isFunctionOrMethod())
1000      SemaRef.CurrentInstantiationScope->InstantiatedLocal(D, Record);
1001  }
1002
1003  Owner->addDecl(Record);
1004  return Record;
1005}
1006
1007/// Normal class members are of more specific types and therefore
1008/// don't make it here.  This function serves two purposes:
1009///   1) instantiating function templates
1010///   2) substituting friend declarations
1011/// FIXME: preserve function definitions in case #2
1012Decl *TemplateDeclInstantiator::VisitFunctionDecl(FunctionDecl *D,
1013                                       TemplateParameterList *TemplateParams) {
1014  // Check whether there is already a function template specialization for
1015  // this declaration.
1016  FunctionTemplateDecl *FunctionTemplate = D->getDescribedFunctionTemplate();
1017  void *InsertPos = 0;
1018  if (FunctionTemplate && !TemplateParams) {
1019    std::pair<const TemplateArgument *, unsigned> Innermost
1020      = TemplateArgs.getInnermost();
1021
1022    FunctionDecl *SpecFunc
1023      = FunctionTemplate->findSpecialization(Innermost.first, Innermost.second,
1024                                             InsertPos);
1025
1026    // If we already have a function template specialization, return it.
1027    if (SpecFunc)
1028      return SpecFunc;
1029  }
1030
1031  bool isFriend;
1032  if (FunctionTemplate)
1033    isFriend = (FunctionTemplate->getFriendObjectKind() != Decl::FOK_None);
1034  else
1035    isFriend = (D->getFriendObjectKind() != Decl::FOK_None);
1036
1037  bool MergeWithParentScope = (TemplateParams != 0) ||
1038    Owner->isFunctionOrMethod() ||
1039    !(isa<Decl>(Owner) &&
1040      cast<Decl>(Owner)->isDefinedOutsideFunctionOrMethod());
1041  LocalInstantiationScope Scope(SemaRef, MergeWithParentScope);
1042
1043  SmallVector<ParmVarDecl *, 4> Params;
1044  TypeSourceInfo *TInfo = D->getTypeSourceInfo();
1045  TInfo = SubstFunctionType(D, Params);
1046  if (!TInfo)
1047    return 0;
1048  QualType T = TInfo->getType();
1049
1050  NestedNameSpecifierLoc QualifierLoc = D->getQualifierLoc();
1051  if (QualifierLoc) {
1052    QualifierLoc = SemaRef.SubstNestedNameSpecifierLoc(QualifierLoc,
1053                                                       TemplateArgs);
1054    if (!QualifierLoc)
1055      return 0;
1056  }
1057
1058  // If we're instantiating a local function declaration, put the result
1059  // in the owner;  otherwise we need to find the instantiated context.
1060  DeclContext *DC;
1061  if (D->getDeclContext()->isFunctionOrMethod())
1062    DC = Owner;
1063  else if (isFriend && QualifierLoc) {
1064    CXXScopeSpec SS;
1065    SS.Adopt(QualifierLoc);
1066    DC = SemaRef.computeDeclContext(SS);
1067    if (!DC) return 0;
1068  } else {
1069    DC = SemaRef.FindInstantiatedContext(D->getLocation(), D->getDeclContext(),
1070                                         TemplateArgs);
1071  }
1072
1073  bool isConstexpr = D->isConstexpr();
1074  // FIXME: check whether the instantiation produces a constexpr function.
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                           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);
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 Redeclaration = false;
1170  bool isExplicitSpecialization = false;
1171
1172  LookupResult Previous(SemaRef, Function->getDeclName(), SourceLocation(),
1173                        Sema::LookupOrdinaryName, Sema::ForRedeclaration);
1174
1175  if (DependentFunctionTemplateSpecializationInfo *Info
1176        = D->getDependentSpecializationInfo()) {
1177    assert(isFriend && "non-friend has dependent specialization info?");
1178
1179    // This needs to be set now for future sanity.
1180    Function->setObjectOfFriendDecl(/*HasPrevious*/ true);
1181
1182    // Instantiate the explicit template arguments.
1183    TemplateArgumentListInfo ExplicitArgs(Info->getLAngleLoc(),
1184                                          Info->getRAngleLoc());
1185    if (SemaRef.Subst(Info->getTemplateArgs(), Info->getNumTemplateArgs(),
1186                      ExplicitArgs, TemplateArgs))
1187      return 0;
1188
1189    // Map the candidate templates to their instantiations.
1190    for (unsigned I = 0, E = Info->getNumTemplates(); I != E; ++I) {
1191      Decl *Temp = SemaRef.FindInstantiatedDecl(D->getLocation(),
1192                                                Info->getTemplate(I),
1193                                                TemplateArgs);
1194      if (!Temp) return 0;
1195
1196      Previous.addDecl(cast<FunctionTemplateDecl>(Temp));
1197    }
1198
1199    if (SemaRef.CheckFunctionTemplateSpecialization(Function,
1200                                                    &ExplicitArgs,
1201                                                    Previous))
1202      Function->setInvalidDecl();
1203
1204    isExplicitSpecialization = true;
1205
1206  } else if (TemplateParams || !FunctionTemplate) {
1207    // Look only into the namespace where the friend would be declared to
1208    // find a previous declaration. This is the innermost enclosing namespace,
1209    // as described in ActOnFriendFunctionDecl.
1210    SemaRef.LookupQualifiedName(Previous, DC);
1211
1212    // In C++, the previous declaration we find might be a tag type
1213    // (class or enum). In this case, the new declaration will hide the
1214    // tag type. Note that this does does not apply if we're declaring a
1215    // typedef (C++ [dcl.typedef]p4).
1216    if (Previous.isSingleTagDecl())
1217      Previous.clear();
1218  }
1219
1220  SemaRef.CheckFunctionDeclaration(/*Scope*/ 0, Function, Previous,
1221                                   isExplicitSpecialization, Redeclaration);
1222
1223  NamedDecl *PrincipalDecl = (TemplateParams
1224                              ? cast<NamedDecl>(FunctionTemplate)
1225                              : Function);
1226
1227  // If the original function was part of a friend declaration,
1228  // inherit its namespace state and add it to the owner.
1229  if (isFriend) {
1230    NamedDecl *PrevDecl;
1231    if (TemplateParams)
1232      PrevDecl = FunctionTemplate->getPreviousDeclaration();
1233    else
1234      PrevDecl = Function->getPreviousDeclaration();
1235
1236    PrincipalDecl->setObjectOfFriendDecl(PrevDecl != 0);
1237    DC->makeDeclVisibleInContext(PrincipalDecl, /*Recoverable=*/ false);
1238
1239    bool queuedInstantiation = false;
1240
1241    if (!SemaRef.getLangOptions().CPlusPlus0x &&
1242        D->isThisDeclarationADefinition()) {
1243      // Check for a function body.
1244      const FunctionDecl *Definition = 0;
1245      if (Function->isDefined(Definition) &&
1246          Definition->getTemplateSpecializationKind() == TSK_Undeclared) {
1247        SemaRef.Diag(Function->getLocation(), diag::err_redefinition)
1248          << Function->getDeclName();
1249        SemaRef.Diag(Definition->getLocation(), diag::note_previous_definition);
1250        Function->setInvalidDecl();
1251      }
1252      // Check for redefinitions due to other instantiations of this or
1253      // a similar friend function.
1254      else for (FunctionDecl::redecl_iterator R = Function->redecls_begin(),
1255                                           REnd = Function->redecls_end();
1256                R != REnd; ++R) {
1257        if (*R == Function)
1258          continue;
1259        switch (R->getFriendObjectKind()) {
1260        case Decl::FOK_None:
1261          if (!queuedInstantiation && R->isUsed(false)) {
1262            if (MemberSpecializationInfo *MSInfo
1263                = Function->getMemberSpecializationInfo()) {
1264              if (MSInfo->getPointOfInstantiation().isInvalid()) {
1265                SourceLocation Loc = R->getLocation(); // FIXME
1266                MSInfo->setPointOfInstantiation(Loc);
1267                SemaRef.PendingLocalImplicitInstantiations.push_back(
1268                                                 std::make_pair(Function, Loc));
1269                queuedInstantiation = true;
1270              }
1271            }
1272          }
1273          break;
1274        default:
1275          if (const FunctionDecl *RPattern
1276              = R->getTemplateInstantiationPattern())
1277            if (RPattern->isDefined(RPattern)) {
1278              SemaRef.Diag(Function->getLocation(), diag::err_redefinition)
1279                << Function->getDeclName();
1280              SemaRef.Diag(R->getLocation(), diag::note_previous_definition);
1281              Function->setInvalidDecl();
1282              break;
1283            }
1284        }
1285      }
1286    }
1287  }
1288
1289  if (Function->isOverloadedOperator() && !DC->isRecord() &&
1290      PrincipalDecl->isInIdentifierNamespace(Decl::IDNS_Ordinary))
1291    PrincipalDecl->setNonMemberOperator();
1292
1293  assert(!D->isDefaulted() && "only methods should be defaulted");
1294  return Function;
1295}
1296
1297Decl *
1298TemplateDeclInstantiator::VisitCXXMethodDecl(CXXMethodDecl *D,
1299                                      TemplateParameterList *TemplateParams,
1300                                      bool IsClassScopeSpecialization) {
1301  FunctionTemplateDecl *FunctionTemplate = D->getDescribedFunctionTemplate();
1302  void *InsertPos = 0;
1303  if (FunctionTemplate && !TemplateParams) {
1304    // We are creating a function template specialization from a function
1305    // template. Check whether there is already a function template
1306    // specialization for this particular set of template arguments.
1307    std::pair<const TemplateArgument *, unsigned> Innermost
1308      = TemplateArgs.getInnermost();
1309
1310    FunctionDecl *SpecFunc
1311      = FunctionTemplate->findSpecialization(Innermost.first, Innermost.second,
1312                                             InsertPos);
1313
1314    // If we already have a function template specialization, return it.
1315    if (SpecFunc)
1316      return SpecFunc;
1317  }
1318
1319  bool isFriend;
1320  if (FunctionTemplate)
1321    isFriend = (FunctionTemplate->getFriendObjectKind() != Decl::FOK_None);
1322  else
1323    isFriend = (D->getFriendObjectKind() != Decl::FOK_None);
1324
1325  bool MergeWithParentScope = (TemplateParams != 0) ||
1326    !(isa<Decl>(Owner) &&
1327      cast<Decl>(Owner)->isDefinedOutsideFunctionOrMethod());
1328  LocalInstantiationScope Scope(SemaRef, MergeWithParentScope);
1329
1330  // Instantiate enclosing template arguments for friends.
1331  SmallVector<TemplateParameterList *, 4> TempParamLists;
1332  unsigned NumTempParamLists = 0;
1333  if (isFriend && (NumTempParamLists = D->getNumTemplateParameterLists())) {
1334    TempParamLists.set_size(NumTempParamLists);
1335    for (unsigned I = 0; I != NumTempParamLists; ++I) {
1336      TemplateParameterList *TempParams = D->getTemplateParameterList(I);
1337      TemplateParameterList *InstParams = SubstTemplateParams(TempParams);
1338      if (!InstParams)
1339        return NULL;
1340      TempParamLists[I] = InstParams;
1341    }
1342  }
1343
1344  SmallVector<ParmVarDecl *, 4> Params;
1345  TypeSourceInfo *TInfo = D->getTypeSourceInfo();
1346  TInfo = SubstFunctionType(D, Params);
1347  if (!TInfo)
1348    return 0;
1349  QualType T = TInfo->getType();
1350
1351  // \brief If the type of this function, after ignoring parentheses,
1352  // is not *directly* a function type, then we're instantiating a function
1353  // that was declared via a typedef, e.g.,
1354  //
1355  //   typedef int functype(int, int);
1356  //   functype func;
1357  //
1358  // In this case, we'll just go instantiate the ParmVarDecls that we
1359  // synthesized in the method declaration.
1360  if (!isa<FunctionProtoType>(T.IgnoreParens())) {
1361    assert(!Params.size() && "Instantiating type could not yield parameters");
1362    SmallVector<QualType, 4> ParamTypes;
1363    if (SemaRef.SubstParmTypes(D->getLocation(), D->param_begin(),
1364                               D->getNumParams(), TemplateArgs, ParamTypes,
1365                               &Params))
1366      return 0;
1367  }
1368
1369  NestedNameSpecifierLoc QualifierLoc = D->getQualifierLoc();
1370  if (QualifierLoc) {
1371    QualifierLoc = SemaRef.SubstNestedNameSpecifierLoc(QualifierLoc,
1372                                                 TemplateArgs);
1373    if (!QualifierLoc)
1374      return 0;
1375  }
1376
1377  DeclContext *DC = Owner;
1378  if (isFriend) {
1379    if (QualifierLoc) {
1380      CXXScopeSpec SS;
1381      SS.Adopt(QualifierLoc);
1382      DC = SemaRef.computeDeclContext(SS);
1383
1384      if (DC && SemaRef.RequireCompleteDeclContext(SS, DC))
1385        return 0;
1386    } else {
1387      DC = SemaRef.FindInstantiatedContext(D->getLocation(),
1388                                           D->getDeclContext(),
1389                                           TemplateArgs);
1390    }
1391    if (!DC) return 0;
1392  }
1393
1394  bool isConstexpr = D->isConstexpr();
1395  // FIXME: check whether the instantiation produces a constexpr function.
1396
1397  // Build the instantiated method declaration.
1398  CXXRecordDecl *Record = cast<CXXRecordDecl>(DC);
1399  CXXMethodDecl *Method = 0;
1400
1401  SourceLocation StartLoc = D->getInnerLocStart();
1402  DeclarationNameInfo NameInfo
1403    = SemaRef.SubstDeclarationNameInfo(D->getNameInfo(), TemplateArgs);
1404  if (CXXConstructorDecl *Constructor = dyn_cast<CXXConstructorDecl>(D)) {
1405    Method = CXXConstructorDecl::Create(SemaRef.Context, Record,
1406                                        StartLoc, NameInfo, T, TInfo,
1407                                        Constructor->isExplicit(),
1408                                        Constructor->isInlineSpecified(),
1409                                        false, isConstexpr);
1410  } else if (CXXDestructorDecl *Destructor = dyn_cast<CXXDestructorDecl>(D)) {
1411    Method = CXXDestructorDecl::Create(SemaRef.Context, Record,
1412                                       StartLoc, NameInfo, T, TInfo,
1413                                       Destructor->isInlineSpecified(),
1414                                       false);
1415  } else if (CXXConversionDecl *Conversion = dyn_cast<CXXConversionDecl>(D)) {
1416    Method = CXXConversionDecl::Create(SemaRef.Context, Record,
1417                                       StartLoc, NameInfo, T, TInfo,
1418                                       Conversion->isInlineSpecified(),
1419                                       Conversion->isExplicit(),
1420                                       isConstexpr, Conversion->getLocEnd());
1421  } else {
1422    Method = CXXMethodDecl::Create(SemaRef.Context, Record,
1423                                   StartLoc, NameInfo, T, TInfo,
1424                                   D->isStatic(),
1425                                   D->getStorageClassAsWritten(),
1426                                   D->isInlineSpecified(),
1427                                   isConstexpr, D->getLocEnd());
1428  }
1429
1430  if (QualifierLoc)
1431    Method->setQualifierInfo(QualifierLoc);
1432
1433  if (TemplateParams) {
1434    // Our resulting instantiation is actually a function template, since we
1435    // are substituting only the outer template parameters. For example, given
1436    //
1437    //   template<typename T>
1438    //   struct X {
1439    //     template<typename U> void f(T, U);
1440    //   };
1441    //
1442    //   X<int> x;
1443    //
1444    // We are instantiating the member template "f" within X<int>, which means
1445    // substituting int for T, but leaving "f" as a member function template.
1446    // Build the function template itself.
1447    FunctionTemplate = FunctionTemplateDecl::Create(SemaRef.Context, Record,
1448                                                    Method->getLocation(),
1449                                                    Method->getDeclName(),
1450                                                    TemplateParams, Method);
1451    if (isFriend) {
1452      FunctionTemplate->setLexicalDeclContext(Owner);
1453      FunctionTemplate->setObjectOfFriendDecl(true);
1454    } else if (D->isOutOfLine())
1455      FunctionTemplate->setLexicalDeclContext(D->getLexicalDeclContext());
1456    Method->setDescribedFunctionTemplate(FunctionTemplate);
1457  } else if (FunctionTemplate) {
1458    // Record this function template specialization.
1459    std::pair<const TemplateArgument *, unsigned> Innermost
1460      = TemplateArgs.getInnermost();
1461    Method->setFunctionTemplateSpecialization(FunctionTemplate,
1462                         TemplateArgumentList::CreateCopy(SemaRef.Context,
1463                                                          Innermost.first,
1464                                                          Innermost.second),
1465                                              InsertPos);
1466  } else if (!isFriend) {
1467    // Record that this is an instantiation of a member function.
1468    Method->setInstantiationOfMemberFunction(D, TSK_ImplicitInstantiation);
1469  }
1470
1471  // If we are instantiating a member function defined
1472  // out-of-line, the instantiation will have the same lexical
1473  // context (which will be a namespace scope) as the template.
1474  if (isFriend) {
1475    if (NumTempParamLists)
1476      Method->setTemplateParameterListsInfo(SemaRef.Context,
1477                                            NumTempParamLists,
1478                                            TempParamLists.data());
1479
1480    Method->setLexicalDeclContext(Owner);
1481    Method->setObjectOfFriendDecl(true);
1482  } else if (D->isOutOfLine())
1483    Method->setLexicalDeclContext(D->getLexicalDeclContext());
1484
1485  // Attach the parameters
1486  for (unsigned P = 0; P < Params.size(); ++P)
1487    Params[P]->setOwningFunction(Method);
1488  Method->setParams(Params);
1489
1490  if (InitMethodInstantiation(Method, D))
1491    Method->setInvalidDecl();
1492
1493  LookupResult Previous(SemaRef, NameInfo, Sema::LookupOrdinaryName,
1494                        Sema::ForRedeclaration);
1495
1496  if (!FunctionTemplate || TemplateParams || isFriend) {
1497    SemaRef.LookupQualifiedName(Previous, Record);
1498
1499    // In C++, the previous declaration we find might be a tag type
1500    // (class or enum). In this case, the new declaration will hide the
1501    // tag type. Note that this does does not apply if we're declaring a
1502    // typedef (C++ [dcl.typedef]p4).
1503    if (Previous.isSingleTagDecl())
1504      Previous.clear();
1505  }
1506
1507  bool Redeclaration = false;
1508  if (!IsClassScopeSpecialization)
1509    SemaRef.CheckFunctionDeclaration(0, Method, Previous, false, Redeclaration);
1510
1511  if (D->isPure())
1512    SemaRef.CheckPureMethod(Method, SourceRange());
1513
1514  Method->setAccess(D->getAccess());
1515
1516  SemaRef.CheckOverrideControl(Method);
1517
1518  if (FunctionTemplate) {
1519    // If there's a function template, let our caller handle it.
1520  } else if (Method->isInvalidDecl() && !Previous.empty()) {
1521    // Don't hide a (potentially) valid declaration with an invalid one.
1522  } else {
1523    NamedDecl *DeclToAdd = (TemplateParams
1524                            ? cast<NamedDecl>(FunctionTemplate)
1525                            : Method);
1526    if (isFriend)
1527      Record->makeDeclVisibleInContext(DeclToAdd);
1528    else if (!IsClassScopeSpecialization)
1529      Owner->addDecl(DeclToAdd);
1530  }
1531
1532  if (D->isExplicitlyDefaulted()) {
1533    SemaRef.SetDeclDefaulted(Method, Method->getLocation());
1534  } else {
1535    assert(!D->isDefaulted() &&
1536           "should not implicitly default uninstantiated function");
1537  }
1538
1539  return Method;
1540}
1541
1542Decl *TemplateDeclInstantiator::VisitCXXConstructorDecl(CXXConstructorDecl *D) {
1543  return VisitCXXMethodDecl(D);
1544}
1545
1546Decl *TemplateDeclInstantiator::VisitCXXDestructorDecl(CXXDestructorDecl *D) {
1547  return VisitCXXMethodDecl(D);
1548}
1549
1550Decl *TemplateDeclInstantiator::VisitCXXConversionDecl(CXXConversionDecl *D) {
1551  return VisitCXXMethodDecl(D);
1552}
1553
1554ParmVarDecl *TemplateDeclInstantiator::VisitParmVarDecl(ParmVarDecl *D) {
1555  return SemaRef.SubstParmVarDecl(D, TemplateArgs, /*indexAdjustment*/ 0,
1556                                  llvm::Optional<unsigned>());
1557}
1558
1559Decl *TemplateDeclInstantiator::VisitTemplateTypeParmDecl(
1560                                                    TemplateTypeParmDecl *D) {
1561  // TODO: don't always clone when decls are refcounted.
1562  assert(D->getTypeForDecl()->isTemplateTypeParmType());
1563
1564  TemplateTypeParmDecl *Inst =
1565    TemplateTypeParmDecl::Create(SemaRef.Context, Owner,
1566                                 D->getLocStart(), D->getLocation(),
1567                                 D->getDepth() - TemplateArgs.getNumLevels(),
1568                                 D->getIndex(), D->getIdentifier(),
1569                                 D->wasDeclaredWithTypename(),
1570                                 D->isParameterPack());
1571  Inst->setAccess(AS_public);
1572
1573  if (D->hasDefaultArgument())
1574    Inst->setDefaultArgument(D->getDefaultArgumentInfo(), false);
1575
1576  // Introduce this template parameter's instantiation into the instantiation
1577  // scope.
1578  SemaRef.CurrentInstantiationScope->InstantiatedLocal(D, Inst);
1579
1580  return Inst;
1581}
1582
1583Decl *TemplateDeclInstantiator::VisitNonTypeTemplateParmDecl(
1584                                                 NonTypeTemplateParmDecl *D) {
1585  // Substitute into the type of the non-type template parameter.
1586  TypeLoc TL = D->getTypeSourceInfo()->getTypeLoc();
1587  SmallVector<TypeSourceInfo *, 4> ExpandedParameterPackTypesAsWritten;
1588  SmallVector<QualType, 4> ExpandedParameterPackTypes;
1589  bool IsExpandedParameterPack = false;
1590  TypeSourceInfo *DI;
1591  QualType T;
1592  bool Invalid = false;
1593
1594  if (D->isExpandedParameterPack()) {
1595    // The non-type template parameter pack is an already-expanded pack
1596    // expansion of types. Substitute into each of the expanded types.
1597    ExpandedParameterPackTypes.reserve(D->getNumExpansionTypes());
1598    ExpandedParameterPackTypesAsWritten.reserve(D->getNumExpansionTypes());
1599    for (unsigned I = 0, N = D->getNumExpansionTypes(); I != N; ++I) {
1600      TypeSourceInfo *NewDI =SemaRef.SubstType(D->getExpansionTypeSourceInfo(I),
1601                                               TemplateArgs,
1602                                               D->getLocation(),
1603                                               D->getDeclName());
1604      if (!NewDI)
1605        return 0;
1606
1607      ExpandedParameterPackTypesAsWritten.push_back(NewDI);
1608      QualType NewT =SemaRef.CheckNonTypeTemplateParameterType(NewDI->getType(),
1609                                                              D->getLocation());
1610      if (NewT.isNull())
1611        return 0;
1612      ExpandedParameterPackTypes.push_back(NewT);
1613    }
1614
1615    IsExpandedParameterPack = true;
1616    DI = D->getTypeSourceInfo();
1617    T = DI->getType();
1618  } else if (isa<PackExpansionTypeLoc>(TL)) {
1619    // The non-type template parameter pack's type is a pack expansion of types.
1620    // Determine whether we need to expand this parameter pack into separate
1621    // types.
1622    PackExpansionTypeLoc Expansion = cast<PackExpansionTypeLoc>(TL);
1623    TypeLoc Pattern = Expansion.getPatternLoc();
1624    SmallVector<UnexpandedParameterPack, 2> Unexpanded;
1625    SemaRef.collectUnexpandedParameterPacks(Pattern, Unexpanded);
1626
1627    // Determine whether the set of unexpanded parameter packs can and should
1628    // be expanded.
1629    bool Expand = true;
1630    bool RetainExpansion = false;
1631    llvm::Optional<unsigned> OrigNumExpansions
1632      = Expansion.getTypePtr()->getNumExpansions();
1633    llvm::Optional<unsigned> NumExpansions = OrigNumExpansions;
1634    if (SemaRef.CheckParameterPacksForExpansion(Expansion.getEllipsisLoc(),
1635                                                Pattern.getSourceRange(),
1636                                                Unexpanded,
1637                                                TemplateArgs,
1638                                                Expand, RetainExpansion,
1639                                                NumExpansions))
1640      return 0;
1641
1642    if (Expand) {
1643      for (unsigned I = 0; I != *NumExpansions; ++I) {
1644        Sema::ArgumentPackSubstitutionIndexRAII SubstIndex(SemaRef, I);
1645        TypeSourceInfo *NewDI = SemaRef.SubstType(Pattern, TemplateArgs,
1646                                                  D->getLocation(),
1647                                                  D->getDeclName());
1648        if (!NewDI)
1649          return 0;
1650
1651        ExpandedParameterPackTypesAsWritten.push_back(NewDI);
1652        QualType NewT = SemaRef.CheckNonTypeTemplateParameterType(
1653                                                              NewDI->getType(),
1654                                                              D->getLocation());
1655        if (NewT.isNull())
1656          return 0;
1657        ExpandedParameterPackTypes.push_back(NewT);
1658      }
1659
1660      // Note that we have an expanded parameter pack. The "type" of this
1661      // expanded parameter pack is the original expansion type, but callers
1662      // will end up using the expanded parameter pack types for type-checking.
1663      IsExpandedParameterPack = true;
1664      DI = D->getTypeSourceInfo();
1665      T = DI->getType();
1666    } else {
1667      // We cannot fully expand the pack expansion now, so substitute into the
1668      // pattern and create a new pack expansion type.
1669      Sema::ArgumentPackSubstitutionIndexRAII SubstIndex(SemaRef, -1);
1670      TypeSourceInfo *NewPattern = SemaRef.SubstType(Pattern, TemplateArgs,
1671                                                     D->getLocation(),
1672                                                     D->getDeclName());
1673      if (!NewPattern)
1674        return 0;
1675
1676      DI = SemaRef.CheckPackExpansion(NewPattern, Expansion.getEllipsisLoc(),
1677                                      NumExpansions);
1678      if (!DI)
1679        return 0;
1680
1681      T = DI->getType();
1682    }
1683  } else {
1684    // Simple case: substitution into a parameter that is not a parameter pack.
1685    DI = SemaRef.SubstType(D->getTypeSourceInfo(), TemplateArgs,
1686                           D->getLocation(), D->getDeclName());
1687    if (!DI)
1688      return 0;
1689
1690    // Check that this type is acceptable for a non-type template parameter.
1691    T = SemaRef.CheckNonTypeTemplateParameterType(DI->getType(),
1692                                                  D->getLocation());
1693    if (T.isNull()) {
1694      T = SemaRef.Context.IntTy;
1695      Invalid = true;
1696    }
1697  }
1698
1699  NonTypeTemplateParmDecl *Param;
1700  if (IsExpandedParameterPack)
1701    Param = NonTypeTemplateParmDecl::Create(SemaRef.Context, Owner,
1702                                            D->getInnerLocStart(),
1703                                            D->getLocation(),
1704                                    D->getDepth() - TemplateArgs.getNumLevels(),
1705                                            D->getPosition(),
1706                                            D->getIdentifier(), T,
1707                                            DI,
1708                                            ExpandedParameterPackTypes.data(),
1709                                            ExpandedParameterPackTypes.size(),
1710                                    ExpandedParameterPackTypesAsWritten.data());
1711  else
1712    Param = NonTypeTemplateParmDecl::Create(SemaRef.Context, Owner,
1713                                            D->getInnerLocStart(),
1714                                            D->getLocation(),
1715                                    D->getDepth() - TemplateArgs.getNumLevels(),
1716                                            D->getPosition(),
1717                                            D->getIdentifier(), T,
1718                                            D->isParameterPack(), DI);
1719
1720  Param->setAccess(AS_public);
1721  if (Invalid)
1722    Param->setInvalidDecl();
1723
1724  Param->setDefaultArgument(D->getDefaultArgument(), false);
1725
1726  // Introduce this template parameter's instantiation into the instantiation
1727  // scope.
1728  SemaRef.CurrentInstantiationScope->InstantiatedLocal(D, Param);
1729  return Param;
1730}
1731
1732Decl *
1733TemplateDeclInstantiator::VisitTemplateTemplateParmDecl(
1734                                                  TemplateTemplateParmDecl *D) {
1735  // Instantiate the template parameter list of the template template parameter.
1736  TemplateParameterList *TempParams = D->getTemplateParameters();
1737  TemplateParameterList *InstParams;
1738  {
1739    // Perform the actual substitution of template parameters within a new,
1740    // local instantiation scope.
1741    LocalInstantiationScope Scope(SemaRef);
1742    InstParams = SubstTemplateParams(TempParams);
1743    if (!InstParams)
1744      return NULL;
1745  }
1746
1747  // Build the template template parameter.
1748  TemplateTemplateParmDecl *Param
1749    = TemplateTemplateParmDecl::Create(SemaRef.Context, Owner, D->getLocation(),
1750                                   D->getDepth() - TemplateArgs.getNumLevels(),
1751                                       D->getPosition(), D->isParameterPack(),
1752                                       D->getIdentifier(), InstParams);
1753  Param->setDefaultArgument(D->getDefaultArgument(), false);
1754  Param->setAccess(AS_public);
1755
1756  // Introduce this template parameter's instantiation into the instantiation
1757  // scope.
1758  SemaRef.CurrentInstantiationScope->InstantiatedLocal(D, Param);
1759
1760  return Param;
1761}
1762
1763Decl *TemplateDeclInstantiator::VisitUsingDirectiveDecl(UsingDirectiveDecl *D) {
1764  // Using directives are never dependent (and never contain any types or
1765  // expressions), so they require no explicit instantiation work.
1766
1767  UsingDirectiveDecl *Inst
1768    = UsingDirectiveDecl::Create(SemaRef.Context, Owner, D->getLocation(),
1769                                 D->getNamespaceKeyLocation(),
1770                                 D->getQualifierLoc(),
1771                                 D->getIdentLocation(),
1772                                 D->getNominatedNamespace(),
1773                                 D->getCommonAncestor());
1774  Owner->addDecl(Inst);
1775  return Inst;
1776}
1777
1778Decl *TemplateDeclInstantiator::VisitUsingDecl(UsingDecl *D) {
1779
1780  // The nested name specifier may be dependent, for example
1781  //     template <typename T> struct t {
1782  //       struct s1 { T f1(); };
1783  //       struct s2 : s1 { using s1::f1; };
1784  //     };
1785  //     template struct t<int>;
1786  // Here, in using s1::f1, s1 refers to t<T>::s1;
1787  // we need to substitute for t<int>::s1.
1788  NestedNameSpecifierLoc QualifierLoc
1789    = SemaRef.SubstNestedNameSpecifierLoc(D->getQualifierLoc(),
1790                                          TemplateArgs);
1791  if (!QualifierLoc)
1792    return 0;
1793
1794  // The name info is non-dependent, so no transformation
1795  // is required.
1796  DeclarationNameInfo NameInfo = D->getNameInfo();
1797
1798  // We only need to do redeclaration lookups if we're in a class
1799  // scope (in fact, it's not really even possible in non-class
1800  // scopes).
1801  bool CheckRedeclaration = Owner->isRecord();
1802
1803  LookupResult Prev(SemaRef, NameInfo, Sema::LookupUsingDeclName,
1804                    Sema::ForRedeclaration);
1805
1806  UsingDecl *NewUD = UsingDecl::Create(SemaRef.Context, Owner,
1807                                       D->getUsingLocation(),
1808                                       QualifierLoc,
1809                                       NameInfo,
1810                                       D->isTypeName());
1811
1812  CXXScopeSpec SS;
1813  SS.Adopt(QualifierLoc);
1814  if (CheckRedeclaration) {
1815    Prev.setHideTags(false);
1816    SemaRef.LookupQualifiedName(Prev, Owner);
1817
1818    // Check for invalid redeclarations.
1819    if (SemaRef.CheckUsingDeclRedeclaration(D->getUsingLocation(),
1820                                            D->isTypeName(), SS,
1821                                            D->getLocation(), Prev))
1822      NewUD->setInvalidDecl();
1823
1824  }
1825
1826  if (!NewUD->isInvalidDecl() &&
1827      SemaRef.CheckUsingDeclQualifier(D->getUsingLocation(), SS,
1828                                      D->getLocation()))
1829    NewUD->setInvalidDecl();
1830
1831  SemaRef.Context.setInstantiatedFromUsingDecl(NewUD, D);
1832  NewUD->setAccess(D->getAccess());
1833  Owner->addDecl(NewUD);
1834
1835  // Don't process the shadow decls for an invalid decl.
1836  if (NewUD->isInvalidDecl())
1837    return NewUD;
1838
1839  bool isFunctionScope = Owner->isFunctionOrMethod();
1840
1841  // Process the shadow decls.
1842  for (UsingDecl::shadow_iterator I = D->shadow_begin(), E = D->shadow_end();
1843         I != E; ++I) {
1844    UsingShadowDecl *Shadow = *I;
1845    NamedDecl *InstTarget =
1846      cast_or_null<NamedDecl>(SemaRef.FindInstantiatedDecl(
1847                                                          Shadow->getLocation(),
1848                                                        Shadow->getTargetDecl(),
1849                                                           TemplateArgs));
1850    if (!InstTarget)
1851      return 0;
1852
1853    if (CheckRedeclaration &&
1854        SemaRef.CheckUsingShadowDecl(NewUD, InstTarget, Prev))
1855      continue;
1856
1857    UsingShadowDecl *InstShadow
1858      = SemaRef.BuildUsingShadowDecl(/*Scope*/ 0, NewUD, InstTarget);
1859    SemaRef.Context.setInstantiatedFromUsingShadowDecl(InstShadow, Shadow);
1860
1861    if (isFunctionScope)
1862      SemaRef.CurrentInstantiationScope->InstantiatedLocal(Shadow, InstShadow);
1863  }
1864
1865  return NewUD;
1866}
1867
1868Decl *TemplateDeclInstantiator::VisitUsingShadowDecl(UsingShadowDecl *D) {
1869  // Ignore these;  we handle them in bulk when processing the UsingDecl.
1870  return 0;
1871}
1872
1873Decl * TemplateDeclInstantiator
1874    ::VisitUnresolvedUsingTypenameDecl(UnresolvedUsingTypenameDecl *D) {
1875  NestedNameSpecifierLoc QualifierLoc
1876    = SemaRef.SubstNestedNameSpecifierLoc(D->getQualifierLoc(),
1877                                          TemplateArgs);
1878  if (!QualifierLoc)
1879    return 0;
1880
1881  CXXScopeSpec SS;
1882  SS.Adopt(QualifierLoc);
1883
1884  // Since NameInfo refers to a typename, it cannot be a C++ special name.
1885  // Hence, no tranformation is required for it.
1886  DeclarationNameInfo NameInfo(D->getDeclName(), D->getLocation());
1887  NamedDecl *UD =
1888    SemaRef.BuildUsingDeclaration(/*Scope*/ 0, D->getAccess(),
1889                                  D->getUsingLoc(), SS, NameInfo, 0,
1890                                  /*instantiation*/ true,
1891                                  /*typename*/ true, D->getTypenameLoc());
1892  if (UD)
1893    SemaRef.Context.setInstantiatedFromUsingDecl(cast<UsingDecl>(UD), D);
1894
1895  return UD;
1896}
1897
1898Decl * TemplateDeclInstantiator
1899    ::VisitUnresolvedUsingValueDecl(UnresolvedUsingValueDecl *D) {
1900  NestedNameSpecifierLoc QualifierLoc
1901      = SemaRef.SubstNestedNameSpecifierLoc(D->getQualifierLoc(), TemplateArgs);
1902  if (!QualifierLoc)
1903    return 0;
1904
1905  CXXScopeSpec SS;
1906  SS.Adopt(QualifierLoc);
1907
1908  DeclarationNameInfo NameInfo
1909    = SemaRef.SubstDeclarationNameInfo(D->getNameInfo(), TemplateArgs);
1910
1911  NamedDecl *UD =
1912    SemaRef.BuildUsingDeclaration(/*Scope*/ 0, D->getAccess(),
1913                                  D->getUsingLoc(), SS, NameInfo, 0,
1914                                  /*instantiation*/ true,
1915                                  /*typename*/ false, SourceLocation());
1916  if (UD)
1917    SemaRef.Context.setInstantiatedFromUsingDecl(cast<UsingDecl>(UD), D);
1918
1919  return UD;
1920}
1921
1922
1923Decl *TemplateDeclInstantiator::VisitClassScopeFunctionSpecializationDecl(
1924                                     ClassScopeFunctionSpecializationDecl *Decl) {
1925  CXXMethodDecl *OldFD = Decl->getSpecialization();
1926  CXXMethodDecl *NewFD = cast<CXXMethodDecl>(VisitCXXMethodDecl(OldFD, 0, true));
1927
1928  LookupResult Previous(SemaRef, NewFD->getNameInfo(), Sema::LookupOrdinaryName,
1929                        Sema::ForRedeclaration);
1930
1931  SemaRef.LookupQualifiedName(Previous, SemaRef.CurContext);
1932  if (SemaRef.CheckFunctionTemplateSpecialization(NewFD, 0, Previous)) {
1933    NewFD->setInvalidDecl();
1934    return NewFD;
1935  }
1936
1937  // Associate the specialization with the pattern.
1938  FunctionDecl *Specialization = cast<FunctionDecl>(Previous.getFoundDecl());
1939  assert(Specialization && "Class scope Specialization is null");
1940  SemaRef.Context.setClassScopeSpecializationPattern(Specialization, OldFD);
1941
1942  return NewFD;
1943}
1944
1945Decl *Sema::SubstDecl(Decl *D, DeclContext *Owner,
1946                      const MultiLevelTemplateArgumentList &TemplateArgs) {
1947  TemplateDeclInstantiator Instantiator(*this, Owner, TemplateArgs);
1948  if (D->isInvalidDecl())
1949    return 0;
1950
1951  return Instantiator.Visit(D);
1952}
1953
1954/// \brief Instantiates a nested template parameter list in the current
1955/// instantiation context.
1956///
1957/// \param L The parameter list to instantiate
1958///
1959/// \returns NULL if there was an error
1960TemplateParameterList *
1961TemplateDeclInstantiator::SubstTemplateParams(TemplateParameterList *L) {
1962  // Get errors for all the parameters before bailing out.
1963  bool Invalid = false;
1964
1965  unsigned N = L->size();
1966  typedef SmallVector<NamedDecl *, 8> ParamVector;
1967  ParamVector Params;
1968  Params.reserve(N);
1969  for (TemplateParameterList::iterator PI = L->begin(), PE = L->end();
1970       PI != PE; ++PI) {
1971    NamedDecl *D = cast_or_null<NamedDecl>(Visit(*PI));
1972    Params.push_back(D);
1973    Invalid = Invalid || !D || D->isInvalidDecl();
1974  }
1975
1976  // Clean up if we had an error.
1977  if (Invalid)
1978    return NULL;
1979
1980  TemplateParameterList *InstL
1981    = TemplateParameterList::Create(SemaRef.Context, L->getTemplateLoc(),
1982                                    L->getLAngleLoc(), &Params.front(), N,
1983                                    L->getRAngleLoc());
1984  return InstL;
1985}
1986
1987/// \brief Instantiate the declaration of a class template partial
1988/// specialization.
1989///
1990/// \param ClassTemplate the (instantiated) class template that is partially
1991// specialized by the instantiation of \p PartialSpec.
1992///
1993/// \param PartialSpec the (uninstantiated) class template partial
1994/// specialization that we are instantiating.
1995///
1996/// \returns The instantiated partial specialization, if successful; otherwise,
1997/// NULL to indicate an error.
1998ClassTemplatePartialSpecializationDecl *
1999TemplateDeclInstantiator::InstantiateClassTemplatePartialSpecialization(
2000                                            ClassTemplateDecl *ClassTemplate,
2001                          ClassTemplatePartialSpecializationDecl *PartialSpec) {
2002  // Create a local instantiation scope for this class template partial
2003  // specialization, which will contain the instantiations of the template
2004  // parameters.
2005  LocalInstantiationScope Scope(SemaRef);
2006
2007  // Substitute into the template parameters of the class template partial
2008  // specialization.
2009  TemplateParameterList *TempParams = PartialSpec->getTemplateParameters();
2010  TemplateParameterList *InstParams = SubstTemplateParams(TempParams);
2011  if (!InstParams)
2012    return 0;
2013
2014  // Substitute into the template arguments of the class template partial
2015  // specialization.
2016  TemplateArgumentListInfo InstTemplateArgs; // no angle locations
2017  if (SemaRef.Subst(PartialSpec->getTemplateArgsAsWritten(),
2018                    PartialSpec->getNumTemplateArgsAsWritten(),
2019                    InstTemplateArgs, TemplateArgs))
2020    return 0;
2021
2022  // Check that the template argument list is well-formed for this
2023  // class template.
2024  SmallVector<TemplateArgument, 4> Converted;
2025  if (SemaRef.CheckTemplateArgumentList(ClassTemplate,
2026                                        PartialSpec->getLocation(),
2027                                        InstTemplateArgs,
2028                                        false,
2029                                        Converted))
2030    return 0;
2031
2032  // Figure out where to insert this class template partial specialization
2033  // in the member template's set of class template partial specializations.
2034  void *InsertPos = 0;
2035  ClassTemplateSpecializationDecl *PrevDecl
2036    = ClassTemplate->findPartialSpecialization(Converted.data(),
2037                                               Converted.size(), InsertPos);
2038
2039  // Build the canonical type that describes the converted template
2040  // arguments of the class template partial specialization.
2041  QualType CanonType
2042    = SemaRef.Context.getTemplateSpecializationType(TemplateName(ClassTemplate),
2043                                                    Converted.data(),
2044                                                    Converted.size());
2045
2046  // Build the fully-sugared type for this class template
2047  // specialization as the user wrote in the specialization
2048  // itself. This means that we'll pretty-print the type retrieved
2049  // from the specialization's declaration the way that the user
2050  // actually wrote the specialization, rather than formatting the
2051  // name based on the "canonical" representation used to store the
2052  // template arguments in the specialization.
2053  TypeSourceInfo *WrittenTy
2054    = SemaRef.Context.getTemplateSpecializationTypeInfo(
2055                                                    TemplateName(ClassTemplate),
2056                                                    PartialSpec->getLocation(),
2057                                                    InstTemplateArgs,
2058                                                    CanonType);
2059
2060  if (PrevDecl) {
2061    // We've already seen a partial specialization with the same template
2062    // parameters and template arguments. This can happen, for example, when
2063    // substituting the outer template arguments ends up causing two
2064    // class template partial specializations of a member class template
2065    // to have identical forms, e.g.,
2066    //
2067    //   template<typename T, typename U>
2068    //   struct Outer {
2069    //     template<typename X, typename Y> struct Inner;
2070    //     template<typename Y> struct Inner<T, Y>;
2071    //     template<typename Y> struct Inner<U, Y>;
2072    //   };
2073    //
2074    //   Outer<int, int> outer; // error: the partial specializations of Inner
2075    //                          // have the same signature.
2076    SemaRef.Diag(PartialSpec->getLocation(), diag::err_partial_spec_redeclared)
2077      << WrittenTy->getType();
2078    SemaRef.Diag(PrevDecl->getLocation(), diag::note_prev_partial_spec_here)
2079      << SemaRef.Context.getTypeDeclType(PrevDecl);
2080    return 0;
2081  }
2082
2083
2084  // Create the class template partial specialization declaration.
2085  ClassTemplatePartialSpecializationDecl *InstPartialSpec
2086    = ClassTemplatePartialSpecializationDecl::Create(SemaRef.Context,
2087                                                     PartialSpec->getTagKind(),
2088                                                     Owner,
2089                                                     PartialSpec->getLocStart(),
2090                                                     PartialSpec->getLocation(),
2091                                                     InstParams,
2092                                                     ClassTemplate,
2093                                                     Converted.data(),
2094                                                     Converted.size(),
2095                                                     InstTemplateArgs,
2096                                                     CanonType,
2097                                                     0,
2098                             ClassTemplate->getNextPartialSpecSequenceNumber());
2099  // Substitute the nested name specifier, if any.
2100  if (SubstQualifier(PartialSpec, InstPartialSpec))
2101    return 0;
2102
2103  InstPartialSpec->setInstantiatedFromMember(PartialSpec);
2104  InstPartialSpec->setTypeAsWritten(WrittenTy);
2105
2106  // Add this partial specialization to the set of class template partial
2107  // specializations.
2108  ClassTemplate->AddPartialSpecialization(InstPartialSpec, InsertPos);
2109  return InstPartialSpec;
2110}
2111
2112TypeSourceInfo*
2113TemplateDeclInstantiator::SubstFunctionType(FunctionDecl *D,
2114                              SmallVectorImpl<ParmVarDecl *> &Params) {
2115  TypeSourceInfo *OldTInfo = D->getTypeSourceInfo();
2116  assert(OldTInfo && "substituting function without type source info");
2117  assert(Params.empty() && "parameter vector is non-empty at start");
2118  TypeSourceInfo *NewTInfo
2119    = SemaRef.SubstFunctionDeclType(OldTInfo, TemplateArgs,
2120                                    D->getTypeSpecStartLoc(),
2121                                    D->getDeclName());
2122  if (!NewTInfo)
2123    return 0;
2124
2125  if (NewTInfo != OldTInfo) {
2126    // Get parameters from the new type info.
2127    TypeLoc OldTL = OldTInfo->getTypeLoc().IgnoreParens();
2128    if (FunctionProtoTypeLoc *OldProtoLoc
2129                                  = dyn_cast<FunctionProtoTypeLoc>(&OldTL)) {
2130      TypeLoc NewTL = NewTInfo->getTypeLoc().IgnoreParens();
2131      FunctionProtoTypeLoc *NewProtoLoc = cast<FunctionProtoTypeLoc>(&NewTL);
2132      assert(NewProtoLoc && "Missing prototype?");
2133      unsigned NewIdx = 0, NumNewParams = NewProtoLoc->getNumArgs();
2134      for (unsigned OldIdx = 0, NumOldParams = OldProtoLoc->getNumArgs();
2135           OldIdx != NumOldParams; ++OldIdx) {
2136        ParmVarDecl *OldParam = OldProtoLoc->getArg(OldIdx);
2137        if (!OldParam->isParameterPack() ||
2138            (NewIdx < NumNewParams &&
2139             NewProtoLoc->getArg(NewIdx)->isParameterPack())) {
2140          // Simple case: normal parameter, or a parameter pack that's
2141          // instantiated to a (still-dependent) parameter pack.
2142          ParmVarDecl *NewParam = NewProtoLoc->getArg(NewIdx++);
2143          Params.push_back(NewParam);
2144          SemaRef.CurrentInstantiationScope->InstantiatedLocal(OldParam,
2145                                                               NewParam);
2146          continue;
2147        }
2148
2149        // Parameter pack: make the instantiation an argument pack.
2150        SemaRef.CurrentInstantiationScope->MakeInstantiatedLocalArgPack(
2151                                                                      OldParam);
2152        unsigned NumArgumentsInExpansion
2153          = SemaRef.getNumArgumentsInExpansion(OldParam->getType(),
2154                                               TemplateArgs);
2155        while (NumArgumentsInExpansion--) {
2156          ParmVarDecl *NewParam = NewProtoLoc->getArg(NewIdx++);
2157          Params.push_back(NewParam);
2158          SemaRef.CurrentInstantiationScope->InstantiatedLocalPackArg(OldParam,
2159                                                                      NewParam);
2160        }
2161      }
2162    }
2163  } else {
2164    // The function type itself was not dependent and therefore no
2165    // substitution occurred. However, we still need to instantiate
2166    // the function parameters themselves.
2167    TypeLoc OldTL = OldTInfo->getTypeLoc().IgnoreParens();
2168    if (FunctionProtoTypeLoc *OldProtoLoc
2169                                    = dyn_cast<FunctionProtoTypeLoc>(&OldTL)) {
2170      for (unsigned i = 0, i_end = OldProtoLoc->getNumArgs(); i != i_end; ++i) {
2171        ParmVarDecl *Parm = VisitParmVarDecl(OldProtoLoc->getArg(i));
2172        if (!Parm)
2173          return 0;
2174        Params.push_back(Parm);
2175      }
2176    }
2177  }
2178  return NewTInfo;
2179}
2180
2181/// \brief Initializes the common fields of an instantiation function
2182/// declaration (New) from the corresponding fields of its template (Tmpl).
2183///
2184/// \returns true if there was an error
2185bool
2186TemplateDeclInstantiator::InitFunctionInstantiation(FunctionDecl *New,
2187                                                    FunctionDecl *Tmpl) {
2188  if (Tmpl->isDeletedAsWritten())
2189    New->setDeletedAsWritten();
2190
2191  // If we are performing substituting explicitly-specified template arguments
2192  // or deduced template arguments into a function template and we reach this
2193  // point, we are now past the point where SFINAE applies and have committed
2194  // to keeping the new function template specialization. We therefore
2195  // convert the active template instantiation for the function template
2196  // into a template instantiation for this specific function template
2197  // specialization, which is not a SFINAE context, so that we diagnose any
2198  // further errors in the declaration itself.
2199  typedef Sema::ActiveTemplateInstantiation ActiveInstType;
2200  ActiveInstType &ActiveInst = SemaRef.ActiveTemplateInstantiations.back();
2201  if (ActiveInst.Kind == ActiveInstType::ExplicitTemplateArgumentSubstitution ||
2202      ActiveInst.Kind == ActiveInstType::DeducedTemplateArgumentSubstitution) {
2203    if (FunctionTemplateDecl *FunTmpl
2204          = dyn_cast<FunctionTemplateDecl>((Decl *)ActiveInst.Entity)) {
2205      assert(FunTmpl->getTemplatedDecl() == Tmpl &&
2206             "Deduction from the wrong function template?");
2207      (void) FunTmpl;
2208      ActiveInst.Kind = ActiveInstType::TemplateInstantiation;
2209      ActiveInst.Entity = reinterpret_cast<uintptr_t>(New);
2210      --SemaRef.NonInstantiationEntries;
2211    }
2212  }
2213
2214  const FunctionProtoType *Proto = Tmpl->getType()->getAs<FunctionProtoType>();
2215  assert(Proto && "Function template without prototype?");
2216
2217  if (Proto->hasExceptionSpec() || Proto->getNoReturnAttr()) {
2218    // The function has an exception specification or a "noreturn"
2219    // attribute. Substitute into each of the exception types.
2220    SmallVector<QualType, 4> Exceptions;
2221    for (unsigned I = 0, N = Proto->getNumExceptions(); I != N; ++I) {
2222      // FIXME: Poor location information!
2223      if (const PackExpansionType *PackExpansion
2224            = Proto->getExceptionType(I)->getAs<PackExpansionType>()) {
2225        // We have a pack expansion. Instantiate it.
2226        SmallVector<UnexpandedParameterPack, 2> Unexpanded;
2227        SemaRef.collectUnexpandedParameterPacks(PackExpansion->getPattern(),
2228                                                Unexpanded);
2229        assert(!Unexpanded.empty() &&
2230               "Pack expansion without parameter packs?");
2231
2232        bool Expand = false;
2233        bool RetainExpansion = false;
2234        llvm::Optional<unsigned> NumExpansions
2235                                          = PackExpansion->getNumExpansions();
2236        if (SemaRef.CheckParameterPacksForExpansion(New->getLocation(),
2237                                                    SourceRange(),
2238                                                    Unexpanded,
2239                                                    TemplateArgs,
2240                                                    Expand,
2241                                                    RetainExpansion,
2242                                                    NumExpansions))
2243          break;
2244
2245        if (!Expand) {
2246          // We can't expand this pack expansion into separate arguments yet;
2247          // just substitute into the pattern and create a new pack expansion
2248          // type.
2249          Sema::ArgumentPackSubstitutionIndexRAII SubstIndex(SemaRef, -1);
2250          QualType T = SemaRef.SubstType(PackExpansion->getPattern(),
2251                                         TemplateArgs,
2252                                       New->getLocation(), New->getDeclName());
2253          if (T.isNull())
2254            break;
2255
2256          T = SemaRef.Context.getPackExpansionType(T, NumExpansions);
2257          Exceptions.push_back(T);
2258          continue;
2259        }
2260
2261        // Substitute into the pack expansion pattern for each template
2262        bool Invalid = false;
2263        for (unsigned ArgIdx = 0; ArgIdx != *NumExpansions; ++ArgIdx) {
2264          Sema::ArgumentPackSubstitutionIndexRAII SubstIndex(SemaRef, ArgIdx);
2265
2266          QualType T = SemaRef.SubstType(PackExpansion->getPattern(),
2267                                         TemplateArgs,
2268                                       New->getLocation(), New->getDeclName());
2269          if (T.isNull()) {
2270            Invalid = true;
2271            break;
2272          }
2273
2274          Exceptions.push_back(T);
2275        }
2276
2277        if (Invalid)
2278          break;
2279
2280        continue;
2281      }
2282
2283      QualType T
2284        = SemaRef.SubstType(Proto->getExceptionType(I), TemplateArgs,
2285                            New->getLocation(), New->getDeclName());
2286      if (T.isNull() ||
2287          SemaRef.CheckSpecifiedExceptionType(T, New->getLocation()))
2288        continue;
2289
2290      Exceptions.push_back(T);
2291    }
2292    Expr *NoexceptExpr = 0;
2293    if (Expr *OldNoexceptExpr = Proto->getNoexceptExpr()) {
2294      EnterExpressionEvaluationContext Unevaluated(SemaRef, Sema::Unevaluated);
2295      ExprResult E = SemaRef.SubstExpr(OldNoexceptExpr, TemplateArgs);
2296      if (E.isUsable())
2297        NoexceptExpr = E.take();
2298    }
2299
2300    // Rebuild the function type
2301
2302    FunctionProtoType::ExtProtoInfo EPI = Proto->getExtProtoInfo();
2303    EPI.ExceptionSpecType = Proto->getExceptionSpecType();
2304    EPI.NumExceptions = Exceptions.size();
2305    EPI.Exceptions = Exceptions.data();
2306    EPI.NoexceptExpr = NoexceptExpr;
2307    EPI.ExtInfo = Proto->getExtInfo();
2308
2309    const FunctionProtoType *NewProto
2310      = New->getType()->getAs<FunctionProtoType>();
2311    assert(NewProto && "Template instantiation without function prototype?");
2312    New->setType(SemaRef.Context.getFunctionType(NewProto->getResultType(),
2313                                                 NewProto->arg_type_begin(),
2314                                                 NewProto->getNumArgs(),
2315                                                 EPI));
2316  }
2317
2318  const FunctionDecl* Definition = Tmpl;
2319
2320  // Get the definition. Leaves the variable unchanged if undefined.
2321  Tmpl->isDefined(Definition);
2322
2323  SemaRef.InstantiateAttrs(TemplateArgs, Definition, New);
2324
2325  return false;
2326}
2327
2328/// \brief Initializes common fields of an instantiated method
2329/// declaration (New) from the corresponding fields of its template
2330/// (Tmpl).
2331///
2332/// \returns true if there was an error
2333bool
2334TemplateDeclInstantiator::InitMethodInstantiation(CXXMethodDecl *New,
2335                                                  CXXMethodDecl *Tmpl) {
2336  if (InitFunctionInstantiation(New, Tmpl))
2337    return true;
2338
2339  New->setAccess(Tmpl->getAccess());
2340  if (Tmpl->isVirtualAsWritten())
2341    New->setVirtualAsWritten(true);
2342
2343  // FIXME: attributes
2344  // FIXME: New needs a pointer to Tmpl
2345  return false;
2346}
2347
2348/// \brief Instantiate the definition of the given function from its
2349/// template.
2350///
2351/// \param PointOfInstantiation the point at which the instantiation was
2352/// required. Note that this is not precisely a "point of instantiation"
2353/// for the function, but it's close.
2354///
2355/// \param Function the already-instantiated declaration of a
2356/// function template specialization or member function of a class template
2357/// specialization.
2358///
2359/// \param Recursive if true, recursively instantiates any functions that
2360/// are required by this instantiation.
2361///
2362/// \param DefinitionRequired if true, then we are performing an explicit
2363/// instantiation where the body of the function is required. Complain if
2364/// there is no such body.
2365void Sema::InstantiateFunctionDefinition(SourceLocation PointOfInstantiation,
2366                                         FunctionDecl *Function,
2367                                         bool Recursive,
2368                                         bool DefinitionRequired) {
2369  if (Function->isInvalidDecl() || Function->isDefined())
2370    return;
2371
2372  // Never instantiate an explicit specialization except if it is a class scope
2373  // explicit specialization.
2374  if (Function->getTemplateSpecializationKind() == TSK_ExplicitSpecialization &&
2375      !Function->getClassScopeSpecializationPattern())
2376    return;
2377
2378  // Find the function body that we'll be substituting.
2379  const FunctionDecl *PatternDecl = Function->getTemplateInstantiationPattern();
2380  assert(PatternDecl && "instantiating a non-template");
2381
2382  Stmt *Pattern = PatternDecl->getBody(PatternDecl);
2383  assert(PatternDecl && "template definition is not a template");
2384  if (!Pattern) {
2385    // Try to find a defaulted definition
2386    PatternDecl->isDefined(PatternDecl);
2387  }
2388  assert(PatternDecl && "template definition is not a template");
2389
2390  // Postpone late parsed template instantiations.
2391  if (PatternDecl->isLateTemplateParsed() &&
2392      !LateTemplateParser) {
2393    PendingInstantiations.push_back(
2394      std::make_pair(Function, PointOfInstantiation));
2395    return;
2396  }
2397
2398  // Call the LateTemplateParser callback if there a need to late parse
2399  // a templated function definition.
2400  if (!Pattern && PatternDecl->isLateTemplateParsed() &&
2401      LateTemplateParser) {
2402    LateTemplateParser(OpaqueParser, PatternDecl);
2403    Pattern = PatternDecl->getBody(PatternDecl);
2404  }
2405
2406  if (!Pattern && !PatternDecl->isDefaulted()) {
2407    if (DefinitionRequired) {
2408      if (Function->getPrimaryTemplate())
2409        Diag(PointOfInstantiation,
2410             diag::err_explicit_instantiation_undefined_func_template)
2411          << Function->getPrimaryTemplate();
2412      else
2413        Diag(PointOfInstantiation,
2414             diag::err_explicit_instantiation_undefined_member)
2415          << 1 << Function->getDeclName() << Function->getDeclContext();
2416
2417      if (PatternDecl)
2418        Diag(PatternDecl->getLocation(),
2419             diag::note_explicit_instantiation_here);
2420      Function->setInvalidDecl();
2421    } else if (Function->getTemplateSpecializationKind()
2422                 == TSK_ExplicitInstantiationDefinition) {
2423      PendingInstantiations.push_back(
2424        std::make_pair(Function, PointOfInstantiation));
2425    }
2426
2427    return;
2428  }
2429
2430  // C++0x [temp.explicit]p9:
2431  //   Except for inline functions, other explicit instantiation declarations
2432  //   have the effect of suppressing the implicit instantiation of the entity
2433  //   to which they refer.
2434  if (Function->getTemplateSpecializationKind()
2435        == TSK_ExplicitInstantiationDeclaration &&
2436      !PatternDecl->isInlined())
2437    return;
2438
2439  InstantiatingTemplate Inst(*this, PointOfInstantiation, Function);
2440  if (Inst)
2441    return;
2442
2443  // If we're performing recursive template instantiation, create our own
2444  // queue of pending implicit instantiations that we will instantiate later,
2445  // while we're still within our own instantiation context.
2446  SmallVector<VTableUse, 16> SavedVTableUses;
2447  std::deque<PendingImplicitInstantiation> SavedPendingInstantiations;
2448  if (Recursive) {
2449    VTableUses.swap(SavedVTableUses);
2450    PendingInstantiations.swap(SavedPendingInstantiations);
2451  }
2452
2453  EnterExpressionEvaluationContext EvalContext(*this,
2454                                               Sema::PotentiallyEvaluated);
2455  ActOnStartOfFunctionDef(0, Function);
2456
2457  // Introduce a new scope where local variable instantiations will be
2458  // recorded, unless we're actually a member function within a local
2459  // class, in which case we need to merge our results with the parent
2460  // scope (of the enclosing function).
2461  bool MergeWithParentScope = false;
2462  if (CXXRecordDecl *Rec = dyn_cast<CXXRecordDecl>(Function->getDeclContext()))
2463    MergeWithParentScope = Rec->isLocalClass();
2464
2465  LocalInstantiationScope Scope(*this, MergeWithParentScope);
2466
2467  // Introduce the instantiated function parameters into the local
2468  // instantiation scope, and set the parameter names to those used
2469  // in the template.
2470  unsigned FParamIdx = 0;
2471  for (unsigned I = 0, N = PatternDecl->getNumParams(); I != N; ++I) {
2472    const ParmVarDecl *PatternParam = PatternDecl->getParamDecl(I);
2473    if (!PatternParam->isParameterPack()) {
2474      // Simple case: not a parameter pack.
2475      assert(FParamIdx < Function->getNumParams());
2476      ParmVarDecl *FunctionParam = Function->getParamDecl(I);
2477      FunctionParam->setDeclName(PatternParam->getDeclName());
2478      Scope.InstantiatedLocal(PatternParam, FunctionParam);
2479      ++FParamIdx;
2480      continue;
2481    }
2482
2483    // Expand the parameter pack.
2484    Scope.MakeInstantiatedLocalArgPack(PatternParam);
2485    for (unsigned NumFParams = Function->getNumParams();
2486         FParamIdx < NumFParams;
2487         ++FParamIdx) {
2488      ParmVarDecl *FunctionParam = Function->getParamDecl(FParamIdx);
2489      FunctionParam->setDeclName(PatternParam->getDeclName());
2490      Scope.InstantiatedLocalPackArg(PatternParam, FunctionParam);
2491    }
2492  }
2493
2494  // Enter the scope of this instantiation. We don't use
2495  // PushDeclContext because we don't have a scope.
2496  Sema::ContextRAII savedContext(*this, Function);
2497
2498  MultiLevelTemplateArgumentList TemplateArgs =
2499    getTemplateInstantiationArgs(Function, 0, false, PatternDecl);
2500
2501  if (PatternDecl->isDefaulted()) {
2502    ActOnFinishFunctionBody(Function, 0, /*IsInstantiation=*/true);
2503
2504    SetDeclDefaulted(Function, PatternDecl->getLocation());
2505  } else {
2506    // If this is a constructor, instantiate the member initializers.
2507    if (const CXXConstructorDecl *Ctor =
2508          dyn_cast<CXXConstructorDecl>(PatternDecl)) {
2509      InstantiateMemInitializers(cast<CXXConstructorDecl>(Function), Ctor,
2510                                 TemplateArgs);
2511    }
2512
2513    // Instantiate the function body.
2514    StmtResult Body = SubstStmt(Pattern, TemplateArgs);
2515
2516    if (Body.isInvalid())
2517      Function->setInvalidDecl();
2518
2519    ActOnFinishFunctionBody(Function, Body.get(),
2520                            /*IsInstantiation=*/true);
2521  }
2522
2523  PerformDependentDiagnostics(PatternDecl, TemplateArgs);
2524
2525  savedContext.pop();
2526
2527  DeclGroupRef DG(Function);
2528  Consumer.HandleTopLevelDecl(DG);
2529
2530  // This class may have local implicit instantiations that need to be
2531  // instantiation within this scope.
2532  PerformPendingInstantiations(/*LocalOnly=*/true);
2533  Scope.Exit();
2534
2535  if (Recursive) {
2536    // Define any pending vtables.
2537    DefineUsedVTables();
2538
2539    // Instantiate any pending implicit instantiations found during the
2540    // instantiation of this template.
2541    PerformPendingInstantiations();
2542
2543    // Restore the set of pending vtables.
2544    assert(VTableUses.empty() &&
2545           "VTableUses should be empty before it is discarded.");
2546    VTableUses.swap(SavedVTableUses);
2547
2548    // Restore the set of pending implicit instantiations.
2549    assert(PendingInstantiations.empty() &&
2550           "PendingInstantiations should be empty before it is discarded.");
2551    PendingInstantiations.swap(SavedPendingInstantiations);
2552  }
2553}
2554
2555/// \brief Instantiate the definition of the given variable from its
2556/// template.
2557///
2558/// \param PointOfInstantiation the point at which the instantiation was
2559/// required. Note that this is not precisely a "point of instantiation"
2560/// for the function, but it's close.
2561///
2562/// \param Var the already-instantiated declaration of a static member
2563/// variable of a class template specialization.
2564///
2565/// \param Recursive if true, recursively instantiates any functions that
2566/// are required by this instantiation.
2567///
2568/// \param DefinitionRequired if true, then we are performing an explicit
2569/// instantiation where an out-of-line definition of the member variable
2570/// is required. Complain if there is no such definition.
2571void Sema::InstantiateStaticDataMemberDefinition(
2572                                          SourceLocation PointOfInstantiation,
2573                                                 VarDecl *Var,
2574                                                 bool Recursive,
2575                                                 bool DefinitionRequired) {
2576  if (Var->isInvalidDecl())
2577    return;
2578
2579  // Find the out-of-line definition of this static data member.
2580  VarDecl *Def = Var->getInstantiatedFromStaticDataMember();
2581  assert(Def && "This data member was not instantiated from a template?");
2582  assert(Def->isStaticDataMember() && "Not a static data member?");
2583  Def = Def->getOutOfLineDefinition();
2584
2585  if (!Def) {
2586    // We did not find an out-of-line definition of this static data member,
2587    // so we won't perform any instantiation. Rather, we rely on the user to
2588    // instantiate this definition (or provide a specialization for it) in
2589    // another translation unit.
2590    if (DefinitionRequired) {
2591      Def = Var->getInstantiatedFromStaticDataMember();
2592      Diag(PointOfInstantiation,
2593           diag::err_explicit_instantiation_undefined_member)
2594        << 2 << Var->getDeclName() << Var->getDeclContext();
2595      Diag(Def->getLocation(), diag::note_explicit_instantiation_here);
2596    } else if (Var->getTemplateSpecializationKind()
2597                 == TSK_ExplicitInstantiationDefinition) {
2598      PendingInstantiations.push_back(
2599        std::make_pair(Var, PointOfInstantiation));
2600    }
2601
2602    return;
2603  }
2604
2605  // Never instantiate an explicit specialization.
2606  if (Var->getTemplateSpecializationKind() == TSK_ExplicitSpecialization)
2607    return;
2608
2609  // C++0x [temp.explicit]p9:
2610  //   Except for inline functions, other explicit instantiation declarations
2611  //   have the effect of suppressing the implicit instantiation of the entity
2612  //   to which they refer.
2613  if (Var->getTemplateSpecializationKind()
2614        == TSK_ExplicitInstantiationDeclaration)
2615    return;
2616
2617  // If we already have a definition, we're done.
2618  if (Var->getDefinition())
2619    return;
2620
2621  InstantiatingTemplate Inst(*this, PointOfInstantiation, Var);
2622  if (Inst)
2623    return;
2624
2625  // If we're performing recursive template instantiation, create our own
2626  // queue of pending implicit instantiations that we will instantiate later,
2627  // while we're still within our own instantiation context.
2628  SmallVector<VTableUse, 16> SavedVTableUses;
2629  std::deque<PendingImplicitInstantiation> SavedPendingInstantiations;
2630  if (Recursive) {
2631    VTableUses.swap(SavedVTableUses);
2632    PendingInstantiations.swap(SavedPendingInstantiations);
2633  }
2634
2635  // Enter the scope of this instantiation. We don't use
2636  // PushDeclContext because we don't have a scope.
2637  ContextRAII previousContext(*this, Var->getDeclContext());
2638
2639  VarDecl *OldVar = Var;
2640  Var = cast_or_null<VarDecl>(SubstDecl(Def, Var->getDeclContext(),
2641                                        getTemplateInstantiationArgs(Var)));
2642
2643  previousContext.pop();
2644
2645  if (Var) {
2646    MemberSpecializationInfo *MSInfo = OldVar->getMemberSpecializationInfo();
2647    assert(MSInfo && "Missing member specialization information?");
2648    Var->setTemplateSpecializationKind(MSInfo->getTemplateSpecializationKind(),
2649                                       MSInfo->getPointOfInstantiation());
2650    DeclGroupRef DG(Var);
2651    Consumer.HandleTopLevelDecl(DG);
2652  }
2653
2654  if (Recursive) {
2655    // Define any newly required vtables.
2656    DefineUsedVTables();
2657
2658    // Instantiate any pending implicit instantiations found during the
2659    // instantiation of this template.
2660    PerformPendingInstantiations();
2661
2662    // Restore the set of pending vtables.
2663    assert(VTableUses.empty() &&
2664           "VTableUses should be empty before it is discarded, "
2665           "while instantiating static data member.");
2666    VTableUses.swap(SavedVTableUses);
2667
2668    // Restore the set of pending implicit instantiations.
2669    assert(PendingInstantiations.empty() &&
2670           "PendingInstantiations should be empty before it is discarded, "
2671           "while instantiating static data member.");
2672    PendingInstantiations.swap(SavedPendingInstantiations);
2673  }
2674}
2675
2676void
2677Sema::InstantiateMemInitializers(CXXConstructorDecl *New,
2678                                 const CXXConstructorDecl *Tmpl,
2679                           const MultiLevelTemplateArgumentList &TemplateArgs) {
2680
2681  SmallVector<CXXCtorInitializer*, 4> NewInits;
2682  bool AnyErrors = false;
2683
2684  // Instantiate all the initializers.
2685  for (CXXConstructorDecl::init_const_iterator Inits = Tmpl->init_begin(),
2686                                            InitsEnd = Tmpl->init_end();
2687       Inits != InitsEnd; ++Inits) {
2688    CXXCtorInitializer *Init = *Inits;
2689
2690    // Only instantiate written initializers, let Sema re-construct implicit
2691    // ones.
2692    if (!Init->isWritten())
2693      continue;
2694
2695    SourceLocation LParenLoc, RParenLoc;
2696    ASTOwningVector<Expr*> NewArgs(*this);
2697
2698    SourceLocation EllipsisLoc;
2699
2700    if (Init->isPackExpansion()) {
2701      // This is a pack expansion. We should expand it now.
2702      TypeLoc BaseTL = Init->getBaseClassInfo()->getTypeLoc();
2703      SmallVector<UnexpandedParameterPack, 2> Unexpanded;
2704      collectUnexpandedParameterPacks(BaseTL, Unexpanded);
2705      bool ShouldExpand = false;
2706      bool RetainExpansion = false;
2707      llvm::Optional<unsigned> NumExpansions;
2708      if (CheckParameterPacksForExpansion(Init->getEllipsisLoc(),
2709                                          BaseTL.getSourceRange(),
2710                                          Unexpanded,
2711                                          TemplateArgs, ShouldExpand,
2712                                          RetainExpansion,
2713                                          NumExpansions)) {
2714        AnyErrors = true;
2715        New->setInvalidDecl();
2716        continue;
2717      }
2718      assert(ShouldExpand && "Partial instantiation of base initializer?");
2719
2720      // Loop over all of the arguments in the argument pack(s),
2721      for (unsigned I = 0; I != *NumExpansions; ++I) {
2722        Sema::ArgumentPackSubstitutionIndexRAII SubstIndex(*this, I);
2723
2724        // Instantiate the initializer.
2725        if (InstantiateInitializer(Init->getInit(), TemplateArgs,
2726                                   LParenLoc, NewArgs, RParenLoc)) {
2727          AnyErrors = true;
2728          break;
2729        }
2730
2731        // Instantiate the base type.
2732        TypeSourceInfo *BaseTInfo = SubstType(Init->getBaseClassInfo(),
2733                                              TemplateArgs,
2734                                              Init->getSourceLocation(),
2735                                              New->getDeclName());
2736        if (!BaseTInfo) {
2737          AnyErrors = true;
2738          break;
2739        }
2740
2741        // Build the initializer.
2742        MemInitResult NewInit = BuildBaseInitializer(BaseTInfo->getType(),
2743                                                     BaseTInfo,
2744                                                     (Expr **)NewArgs.data(),
2745                                                     NewArgs.size(),
2746                                                     Init->getLParenLoc(),
2747                                                     Init->getRParenLoc(),
2748                                                     New->getParent(),
2749                                                     SourceLocation());
2750        if (NewInit.isInvalid()) {
2751          AnyErrors = true;
2752          break;
2753        }
2754
2755        NewInits.push_back(NewInit.get());
2756        NewArgs.clear();
2757      }
2758
2759      continue;
2760    }
2761
2762    // Instantiate the initializer.
2763    if (InstantiateInitializer(Init->getInit(), TemplateArgs,
2764                               LParenLoc, NewArgs, RParenLoc)) {
2765      AnyErrors = true;
2766      continue;
2767    }
2768
2769    MemInitResult NewInit;
2770    if (Init->isBaseInitializer()) {
2771      TypeSourceInfo *BaseTInfo = SubstType(Init->getBaseClassInfo(),
2772                                            TemplateArgs,
2773                                            Init->getSourceLocation(),
2774                                            New->getDeclName());
2775      if (!BaseTInfo) {
2776        AnyErrors = true;
2777        New->setInvalidDecl();
2778        continue;
2779      }
2780
2781      NewInit = BuildBaseInitializer(BaseTInfo->getType(), BaseTInfo,
2782                                     (Expr **)NewArgs.data(),
2783                                     NewArgs.size(),
2784                                     Init->getLParenLoc(),
2785                                     Init->getRParenLoc(),
2786                                     New->getParent(),
2787                                     EllipsisLoc);
2788    } else if (Init->isMemberInitializer()) {
2789      FieldDecl *Member = cast_or_null<FieldDecl>(FindInstantiatedDecl(
2790                                                     Init->getMemberLocation(),
2791                                                     Init->getMember(),
2792                                                     TemplateArgs));
2793      if (!Member) {
2794        AnyErrors = true;
2795        New->setInvalidDecl();
2796        continue;
2797      }
2798
2799      NewInit = BuildMemberInitializer(Member, (Expr **)NewArgs.data(),
2800                                       NewArgs.size(),
2801                                       Init->getSourceLocation(),
2802                                       Init->getLParenLoc(),
2803                                       Init->getRParenLoc());
2804    } else if (Init->isIndirectMemberInitializer()) {
2805      IndirectFieldDecl *IndirectMember =
2806         cast_or_null<IndirectFieldDecl>(FindInstantiatedDecl(
2807                                 Init->getMemberLocation(),
2808                                 Init->getIndirectMember(), TemplateArgs));
2809
2810      if (!IndirectMember) {
2811        AnyErrors = true;
2812        New->setInvalidDecl();
2813        continue;
2814      }
2815
2816      NewInit = BuildMemberInitializer(IndirectMember, (Expr **)NewArgs.data(),
2817                                       NewArgs.size(),
2818                                       Init->getSourceLocation(),
2819                                       Init->getLParenLoc(),
2820                                       Init->getRParenLoc());
2821    }
2822
2823    if (NewInit.isInvalid()) {
2824      AnyErrors = true;
2825      New->setInvalidDecl();
2826    } else {
2827      // FIXME: It would be nice if ASTOwningVector had a release function.
2828      NewArgs.take();
2829
2830      NewInits.push_back(NewInit.get());
2831    }
2832  }
2833
2834  // Assign all the initializers to the new constructor.
2835  ActOnMemInitializers(New,
2836                       /*FIXME: ColonLoc */
2837                       SourceLocation(),
2838                       NewInits.data(), NewInits.size(),
2839                       AnyErrors);
2840}
2841
2842// TODO: this could be templated if the various decl types used the
2843// same method name.
2844static bool isInstantiationOf(ClassTemplateDecl *Pattern,
2845                              ClassTemplateDecl *Instance) {
2846  Pattern = Pattern->getCanonicalDecl();
2847
2848  do {
2849    Instance = Instance->getCanonicalDecl();
2850    if (Pattern == Instance) return true;
2851    Instance = Instance->getInstantiatedFromMemberTemplate();
2852  } while (Instance);
2853
2854  return false;
2855}
2856
2857static bool isInstantiationOf(FunctionTemplateDecl *Pattern,
2858                              FunctionTemplateDecl *Instance) {
2859  Pattern = Pattern->getCanonicalDecl();
2860
2861  do {
2862    Instance = Instance->getCanonicalDecl();
2863    if (Pattern == Instance) return true;
2864    Instance = Instance->getInstantiatedFromMemberTemplate();
2865  } while (Instance);
2866
2867  return false;
2868}
2869
2870static bool
2871isInstantiationOf(ClassTemplatePartialSpecializationDecl *Pattern,
2872                  ClassTemplatePartialSpecializationDecl *Instance) {
2873  Pattern
2874    = cast<ClassTemplatePartialSpecializationDecl>(Pattern->getCanonicalDecl());
2875  do {
2876    Instance = cast<ClassTemplatePartialSpecializationDecl>(
2877                                                Instance->getCanonicalDecl());
2878    if (Pattern == Instance)
2879      return true;
2880    Instance = Instance->getInstantiatedFromMember();
2881  } while (Instance);
2882
2883  return false;
2884}
2885
2886static bool isInstantiationOf(CXXRecordDecl *Pattern,
2887                              CXXRecordDecl *Instance) {
2888  Pattern = Pattern->getCanonicalDecl();
2889
2890  do {
2891    Instance = Instance->getCanonicalDecl();
2892    if (Pattern == Instance) return true;
2893    Instance = Instance->getInstantiatedFromMemberClass();
2894  } while (Instance);
2895
2896  return false;
2897}
2898
2899static bool isInstantiationOf(FunctionDecl *Pattern,
2900                              FunctionDecl *Instance) {
2901  Pattern = Pattern->getCanonicalDecl();
2902
2903  do {
2904    Instance = Instance->getCanonicalDecl();
2905    if (Pattern == Instance) return true;
2906    Instance = Instance->getInstantiatedFromMemberFunction();
2907  } while (Instance);
2908
2909  return false;
2910}
2911
2912static bool isInstantiationOf(EnumDecl *Pattern,
2913                              EnumDecl *Instance) {
2914  Pattern = Pattern->getCanonicalDecl();
2915
2916  do {
2917    Instance = Instance->getCanonicalDecl();
2918    if (Pattern == Instance) return true;
2919    Instance = Instance->getInstantiatedFromMemberEnum();
2920  } while (Instance);
2921
2922  return false;
2923}
2924
2925static bool isInstantiationOf(UsingShadowDecl *Pattern,
2926                              UsingShadowDecl *Instance,
2927                              ASTContext &C) {
2928  return C.getInstantiatedFromUsingShadowDecl(Instance) == Pattern;
2929}
2930
2931static bool isInstantiationOf(UsingDecl *Pattern,
2932                              UsingDecl *Instance,
2933                              ASTContext &C) {
2934  return C.getInstantiatedFromUsingDecl(Instance) == Pattern;
2935}
2936
2937static bool isInstantiationOf(UnresolvedUsingValueDecl *Pattern,
2938                              UsingDecl *Instance,
2939                              ASTContext &C) {
2940  return C.getInstantiatedFromUsingDecl(Instance) == Pattern;
2941}
2942
2943static bool isInstantiationOf(UnresolvedUsingTypenameDecl *Pattern,
2944                              UsingDecl *Instance,
2945                              ASTContext &C) {
2946  return C.getInstantiatedFromUsingDecl(Instance) == Pattern;
2947}
2948
2949static bool isInstantiationOfStaticDataMember(VarDecl *Pattern,
2950                                              VarDecl *Instance) {
2951  assert(Instance->isStaticDataMember());
2952
2953  Pattern = Pattern->getCanonicalDecl();
2954
2955  do {
2956    Instance = Instance->getCanonicalDecl();
2957    if (Pattern == Instance) return true;
2958    Instance = Instance->getInstantiatedFromStaticDataMember();
2959  } while (Instance);
2960
2961  return false;
2962}
2963
2964// Other is the prospective instantiation
2965// D is the prospective pattern
2966static bool isInstantiationOf(ASTContext &Ctx, NamedDecl *D, Decl *Other) {
2967  if (D->getKind() != Other->getKind()) {
2968    if (UnresolvedUsingTypenameDecl *UUD
2969          = dyn_cast<UnresolvedUsingTypenameDecl>(D)) {
2970      if (UsingDecl *UD = dyn_cast<UsingDecl>(Other)) {
2971        return isInstantiationOf(UUD, UD, Ctx);
2972      }
2973    }
2974
2975    if (UnresolvedUsingValueDecl *UUD
2976          = dyn_cast<UnresolvedUsingValueDecl>(D)) {
2977      if (UsingDecl *UD = dyn_cast<UsingDecl>(Other)) {
2978        return isInstantiationOf(UUD, UD, Ctx);
2979      }
2980    }
2981
2982    return false;
2983  }
2984
2985  if (CXXRecordDecl *Record = dyn_cast<CXXRecordDecl>(Other))
2986    return isInstantiationOf(cast<CXXRecordDecl>(D), Record);
2987
2988  if (FunctionDecl *Function = dyn_cast<FunctionDecl>(Other))
2989    return isInstantiationOf(cast<FunctionDecl>(D), Function);
2990
2991  if (EnumDecl *Enum = dyn_cast<EnumDecl>(Other))
2992    return isInstantiationOf(cast<EnumDecl>(D), Enum);
2993
2994  if (VarDecl *Var = dyn_cast<VarDecl>(Other))
2995    if (Var->isStaticDataMember())
2996      return isInstantiationOfStaticDataMember(cast<VarDecl>(D), Var);
2997
2998  if (ClassTemplateDecl *Temp = dyn_cast<ClassTemplateDecl>(Other))
2999    return isInstantiationOf(cast<ClassTemplateDecl>(D), Temp);
3000
3001  if (FunctionTemplateDecl *Temp = dyn_cast<FunctionTemplateDecl>(Other))
3002    return isInstantiationOf(cast<FunctionTemplateDecl>(D), Temp);
3003
3004  if (ClassTemplatePartialSpecializationDecl *PartialSpec
3005        = dyn_cast<ClassTemplatePartialSpecializationDecl>(Other))
3006    return isInstantiationOf(cast<ClassTemplatePartialSpecializationDecl>(D),
3007                             PartialSpec);
3008
3009  if (FieldDecl *Field = dyn_cast<FieldDecl>(Other)) {
3010    if (!Field->getDeclName()) {
3011      // This is an unnamed field.
3012      return Ctx.getInstantiatedFromUnnamedFieldDecl(Field) ==
3013        cast<FieldDecl>(D);
3014    }
3015  }
3016
3017  if (UsingDecl *Using = dyn_cast<UsingDecl>(Other))
3018    return isInstantiationOf(cast<UsingDecl>(D), Using, Ctx);
3019
3020  if (UsingShadowDecl *Shadow = dyn_cast<UsingShadowDecl>(Other))
3021    return isInstantiationOf(cast<UsingShadowDecl>(D), Shadow, Ctx);
3022
3023  return D->getDeclName() && isa<NamedDecl>(Other) &&
3024    D->getDeclName() == cast<NamedDecl>(Other)->getDeclName();
3025}
3026
3027template<typename ForwardIterator>
3028static NamedDecl *findInstantiationOf(ASTContext &Ctx,
3029                                      NamedDecl *D,
3030                                      ForwardIterator first,
3031                                      ForwardIterator last) {
3032  for (; first != last; ++first)
3033    if (isInstantiationOf(Ctx, D, *first))
3034      return cast<NamedDecl>(*first);
3035
3036  return 0;
3037}
3038
3039/// \brief Finds the instantiation of the given declaration context
3040/// within the current instantiation.
3041///
3042/// \returns NULL if there was an error
3043DeclContext *Sema::FindInstantiatedContext(SourceLocation Loc, DeclContext* DC,
3044                          const MultiLevelTemplateArgumentList &TemplateArgs) {
3045  if (NamedDecl *D = dyn_cast<NamedDecl>(DC)) {
3046    Decl* ID = FindInstantiatedDecl(Loc, D, TemplateArgs);
3047    return cast_or_null<DeclContext>(ID);
3048  } else return DC;
3049}
3050
3051/// \brief Find the instantiation of the given declaration within the
3052/// current instantiation.
3053///
3054/// This routine is intended to be used when \p D is a declaration
3055/// referenced from within a template, that needs to mapped into the
3056/// corresponding declaration within an instantiation. For example,
3057/// given:
3058///
3059/// \code
3060/// template<typename T>
3061/// struct X {
3062///   enum Kind {
3063///     KnownValue = sizeof(T)
3064///   };
3065///
3066///   bool getKind() const { return KnownValue; }
3067/// };
3068///
3069/// template struct X<int>;
3070/// \endcode
3071///
3072/// In the instantiation of X<int>::getKind(), we need to map the
3073/// EnumConstantDecl for KnownValue (which refers to
3074/// X<T>::<Kind>::KnownValue) to its instantiation
3075/// (X<int>::<Kind>::KnownValue). InstantiateCurrentDeclRef() performs
3076/// this mapping from within the instantiation of X<int>.
3077NamedDecl *Sema::FindInstantiatedDecl(SourceLocation Loc, NamedDecl *D,
3078                          const MultiLevelTemplateArgumentList &TemplateArgs) {
3079  DeclContext *ParentDC = D->getDeclContext();
3080  if (isa<ParmVarDecl>(D) || isa<NonTypeTemplateParmDecl>(D) ||
3081      isa<TemplateTypeParmDecl>(D) || isa<TemplateTemplateParmDecl>(D) ||
3082      (ParentDC->isFunctionOrMethod() && ParentDC->isDependentContext())) {
3083    // D is a local of some kind. Look into the map of local
3084    // declarations to their instantiations.
3085    typedef LocalInstantiationScope::DeclArgumentPack DeclArgumentPack;
3086    llvm::PointerUnion<Decl *, DeclArgumentPack *> *Found
3087      = CurrentInstantiationScope->findInstantiationOf(D);
3088
3089    if (Found) {
3090      if (Decl *FD = Found->dyn_cast<Decl *>())
3091        return cast<NamedDecl>(FD);
3092
3093      unsigned PackIdx = ArgumentPackSubstitutionIndex;
3094      return cast<NamedDecl>((*Found->get<DeclArgumentPack *>())[PackIdx]);
3095    }
3096
3097    // If we didn't find the decl, then we must have a label decl that hasn't
3098    // been found yet.  Lazily instantiate it and return it now.
3099    assert(isa<LabelDecl>(D));
3100
3101    Decl *Inst = SubstDecl(D, CurContext, TemplateArgs);
3102    assert(Inst && "Failed to instantiate label??");
3103
3104    CurrentInstantiationScope->InstantiatedLocal(D, Inst);
3105    return cast<LabelDecl>(Inst);
3106  }
3107
3108  if (CXXRecordDecl *Record = dyn_cast<CXXRecordDecl>(D)) {
3109    if (!Record->isDependentContext())
3110      return D;
3111
3112    // If the RecordDecl is actually the injected-class-name or a
3113    // "templated" declaration for a class template, class template
3114    // partial specialization, or a member class of a class template,
3115    // substitute into the injected-class-name of the class template
3116    // or partial specialization to find the new DeclContext.
3117    QualType T;
3118    ClassTemplateDecl *ClassTemplate = Record->getDescribedClassTemplate();
3119
3120    if (ClassTemplate) {
3121      T = ClassTemplate->getInjectedClassNameSpecialization();
3122    } else if (ClassTemplatePartialSpecializationDecl *PartialSpec
3123                 = dyn_cast<ClassTemplatePartialSpecializationDecl>(Record)) {
3124      ClassTemplate = PartialSpec->getSpecializedTemplate();
3125
3126      // If we call SubstType with an InjectedClassNameType here we
3127      // can end up in an infinite loop.
3128      T = Context.getTypeDeclType(Record);
3129      assert(isa<InjectedClassNameType>(T) &&
3130             "type of partial specialization is not an InjectedClassNameType");
3131      T = cast<InjectedClassNameType>(T)->getInjectedSpecializationType();
3132    }
3133
3134    if (!T.isNull()) {
3135      // Substitute into the injected-class-name to get the type
3136      // corresponding to the instantiation we want, which may also be
3137      // the current instantiation (if we're in a template
3138      // definition). This substitution should never fail, since we
3139      // know we can instantiate the injected-class-name or we
3140      // wouldn't have gotten to the injected-class-name!
3141
3142      // FIXME: Can we use the CurrentInstantiationScope to avoid this
3143      // extra instantiation in the common case?
3144      T = SubstType(T, TemplateArgs, Loc, DeclarationName());
3145      assert(!T.isNull() && "Instantiation of injected-class-name cannot fail.");
3146
3147      if (!T->isDependentType()) {
3148        assert(T->isRecordType() && "Instantiation must produce a record type");
3149        return T->getAs<RecordType>()->getDecl();
3150      }
3151
3152      // We are performing "partial" template instantiation to create
3153      // the member declarations for the members of a class template
3154      // specialization. Therefore, D is actually referring to something
3155      // in the current instantiation. Look through the current
3156      // context, which contains actual instantiations, to find the
3157      // instantiation of the "current instantiation" that D refers
3158      // to.
3159      bool SawNonDependentContext = false;
3160      for (DeclContext *DC = CurContext; !DC->isFileContext();
3161           DC = DC->getParent()) {
3162        if (ClassTemplateSpecializationDecl *Spec
3163                          = dyn_cast<ClassTemplateSpecializationDecl>(DC))
3164          if (isInstantiationOf(ClassTemplate,
3165                                Spec->getSpecializedTemplate()))
3166            return Spec;
3167
3168        if (!DC->isDependentContext())
3169          SawNonDependentContext = true;
3170      }
3171
3172      // We're performing "instantiation" of a member of the current
3173      // instantiation while we are type-checking the
3174      // definition. Compute the declaration context and return that.
3175      assert(!SawNonDependentContext &&
3176             "No dependent context while instantiating record");
3177      DeclContext *DC = computeDeclContext(T);
3178      assert(DC &&
3179             "Unable to find declaration for the current instantiation");
3180      return cast<CXXRecordDecl>(DC);
3181    }
3182
3183    // Fall through to deal with other dependent record types (e.g.,
3184    // anonymous unions in class templates).
3185  }
3186
3187  if (!ParentDC->isDependentContext())
3188    return D;
3189
3190  ParentDC = FindInstantiatedContext(Loc, ParentDC, TemplateArgs);
3191  if (!ParentDC)
3192    return 0;
3193
3194  if (ParentDC != D->getDeclContext()) {
3195    // We performed some kind of instantiation in the parent context,
3196    // so now we need to look into the instantiated parent context to
3197    // find the instantiation of the declaration D.
3198
3199    // If our context used to be dependent, we may need to instantiate
3200    // it before performing lookup into that context.
3201    bool IsBeingInstantiated = false;
3202    if (CXXRecordDecl *Spec = dyn_cast<CXXRecordDecl>(ParentDC)) {
3203      if (!Spec->isDependentContext()) {
3204        QualType T = Context.getTypeDeclType(Spec);
3205        const RecordType *Tag = T->getAs<RecordType>();
3206        assert(Tag && "type of non-dependent record is not a RecordType");
3207        if (Tag->isBeingDefined())
3208          IsBeingInstantiated = true;
3209        if (!Tag->isBeingDefined() &&
3210            RequireCompleteType(Loc, T, diag::err_incomplete_type))
3211          return 0;
3212
3213        ParentDC = Tag->getDecl();
3214      }
3215    }
3216
3217    NamedDecl *Result = 0;
3218    if (D->getDeclName()) {
3219      DeclContext::lookup_result Found = ParentDC->lookup(D->getDeclName());
3220      Result = findInstantiationOf(Context, D, Found.first, Found.second);
3221    } else {
3222      // Since we don't have a name for the entity we're looking for,
3223      // our only option is to walk through all of the declarations to
3224      // find that name. This will occur in a few cases:
3225      //
3226      //   - anonymous struct/union within a template
3227      //   - unnamed class/struct/union/enum within a template
3228      //
3229      // FIXME: Find a better way to find these instantiations!
3230      Result = findInstantiationOf(Context, D,
3231                                   ParentDC->decls_begin(),
3232                                   ParentDC->decls_end());
3233    }
3234
3235    if (!Result) {
3236      if (isa<UsingShadowDecl>(D)) {
3237        // UsingShadowDecls can instantiate to nothing because of using hiding.
3238      } else if (Diags.hasErrorOccurred()) {
3239        // We've already complained about something, so most likely this
3240        // declaration failed to instantiate. There's no point in complaining
3241        // further, since this is normal in invalid code.
3242      } else if (IsBeingInstantiated) {
3243        // The class in which this member exists is currently being
3244        // instantiated, and we haven't gotten around to instantiating this
3245        // member yet. This can happen when the code uses forward declarations
3246        // of member classes, and introduces ordering dependencies via
3247        // template instantiation.
3248        Diag(Loc, diag::err_member_not_yet_instantiated)
3249          << D->getDeclName()
3250          << Context.getTypeDeclType(cast<CXXRecordDecl>(ParentDC));
3251        Diag(D->getLocation(), diag::note_non_instantiated_member_here);
3252      } else {
3253        // We should have found something, but didn't.
3254        llvm_unreachable("Unable to find instantiation of declaration!");
3255      }
3256    }
3257
3258    D = Result;
3259  }
3260
3261  return D;
3262}
3263
3264/// \brief Performs template instantiation for all implicit template
3265/// instantiations we have seen until this point.
3266void Sema::PerformPendingInstantiations(bool LocalOnly) {
3267  // Load pending instantiations from the external source.
3268  if (!LocalOnly && ExternalSource) {
3269    SmallVector<std::pair<ValueDecl *, SourceLocation>, 4> Pending;
3270    ExternalSource->ReadPendingInstantiations(Pending);
3271    PendingInstantiations.insert(PendingInstantiations.begin(),
3272                                 Pending.begin(), Pending.end());
3273  }
3274
3275  while (!PendingLocalImplicitInstantiations.empty() ||
3276         (!LocalOnly && !PendingInstantiations.empty())) {
3277    PendingImplicitInstantiation Inst;
3278
3279    if (PendingLocalImplicitInstantiations.empty()) {
3280      Inst = PendingInstantiations.front();
3281      PendingInstantiations.pop_front();
3282    } else {
3283      Inst = PendingLocalImplicitInstantiations.front();
3284      PendingLocalImplicitInstantiations.pop_front();
3285    }
3286
3287    // Instantiate function definitions
3288    if (FunctionDecl *Function = dyn_cast<FunctionDecl>(Inst.first)) {
3289      PrettyDeclStackTraceEntry CrashInfo(*this, Function, SourceLocation(),
3290                                          "instantiating function definition");
3291      bool DefinitionRequired = Function->getTemplateSpecializationKind() ==
3292                                TSK_ExplicitInstantiationDefinition;
3293      InstantiateFunctionDefinition(/*FIXME:*/Inst.second, Function, true,
3294                                    DefinitionRequired);
3295      continue;
3296    }
3297
3298    // Instantiate static data member definitions.
3299    VarDecl *Var = cast<VarDecl>(Inst.first);
3300    assert(Var->isStaticDataMember() && "Not a static data member?");
3301
3302    // Don't try to instantiate declarations if the most recent redeclaration
3303    // is invalid.
3304    if (Var->getMostRecentDeclaration()->isInvalidDecl())
3305      continue;
3306
3307    // Check if the most recent declaration has changed the specialization kind
3308    // and removed the need for implicit instantiation.
3309    switch (Var->getMostRecentDeclaration()->getTemplateSpecializationKind()) {
3310    case TSK_Undeclared:
3311      assert(false && "Cannot instantitiate an undeclared specialization.");
3312    case TSK_ExplicitInstantiationDeclaration:
3313    case TSK_ExplicitSpecialization:
3314      continue;  // No longer need to instantiate this type.
3315    case TSK_ExplicitInstantiationDefinition:
3316      // We only need an instantiation if the pending instantiation *is* the
3317      // explicit instantiation.
3318      if (Var != Var->getMostRecentDeclaration()) continue;
3319    case TSK_ImplicitInstantiation:
3320      break;
3321    }
3322
3323    PrettyDeclStackTraceEntry CrashInfo(*this, Var, Var->getLocation(),
3324                                        "instantiating static data member "
3325                                        "definition");
3326
3327    bool DefinitionRequired = Var->getTemplateSpecializationKind() ==
3328                              TSK_ExplicitInstantiationDefinition;
3329    InstantiateStaticDataMemberDefinition(/*FIXME:*/Inst.second, Var, true,
3330                                          DefinitionRequired);
3331  }
3332}
3333
3334void Sema::PerformDependentDiagnostics(const DeclContext *Pattern,
3335                       const MultiLevelTemplateArgumentList &TemplateArgs) {
3336  for (DeclContext::ddiag_iterator I = Pattern->ddiag_begin(),
3337         E = Pattern->ddiag_end(); I != E; ++I) {
3338    DependentDiagnostic *DD = *I;
3339
3340    switch (DD->getKind()) {
3341    case DependentDiagnostic::Access:
3342      HandleDependentAccessCheck(*DD, TemplateArgs);
3343      break;
3344    }
3345  }
3346}
3347