SemaTemplateInstantiateDecl.cpp revision 6e4a3f5c59664af13e02e9bb58c2810b830e3b96 
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  FunctionDecl *Function =
1074      FunctionDecl::Create(SemaRef.Context, DC, D->getInnerLocStart(),
1075                           D->getLocation(), D->getDeclName(), T, TInfo,
1076                           D->getStorageClass(), D->getStorageClassAsWritten(),
1077                           D->isInlineSpecified(), D->hasWrittenPrototype());
1078
1079  if (QualifierLoc)
1080    Function->setQualifierInfo(QualifierLoc);
1081
1082  DeclContext *LexicalDC = Owner;
1083  if (!isFriend && D->isOutOfLine()) {
1084    assert(D->getDeclContext()->isFileContext());
1085    LexicalDC = D->getDeclContext();
1086  }
1087
1088  Function->setLexicalDeclContext(LexicalDC);
1089
1090  // Attach the parameters
1091  if (isa<FunctionProtoType>(Function->getType().IgnoreParens())) {
1092    // Adopt the already-instantiated parameters into our own context.
1093    for (unsigned P = 0; P < Params.size(); ++P)
1094      if (Params[P])
1095        Params[P]->setOwningFunction(Function);
1096  } else {
1097    // Since we were instantiated via a typedef of a function type, create
1098    // new parameters.
1099    const FunctionProtoType *Proto
1100      = Function->getType()->getAs<FunctionProtoType>();
1101    assert(Proto && "No function prototype in template instantiation?");
1102    for (FunctionProtoType::arg_type_iterator AI = Proto->arg_type_begin(),
1103         AE = Proto->arg_type_end(); AI != AE; ++AI) {
1104      ParmVarDecl *Param
1105        = SemaRef.BuildParmVarDeclForTypedef(Function, Function->getLocation(),
1106                                             *AI);
1107      Param->setScopeInfo(0, Params.size());
1108      Params.push_back(Param);
1109    }
1110  }
1111  Function->setParams(Params.data(), Params.size());
1112
1113  SourceLocation InstantiateAtPOI;
1114  if (TemplateParams) {
1115    // Our resulting instantiation is actually a function template, since we
1116    // are substituting only the outer template parameters. For example, given
1117    //
1118    //   template<typename T>
1119    //   struct X {
1120    //     template<typename U> friend void f(T, U);
1121    //   };
1122    //
1123    //   X<int> x;
1124    //
1125    // We are instantiating the friend function template "f" within X<int>,
1126    // which means substituting int for T, but leaving "f" as a friend function
1127    // template.
1128    // Build the function template itself.
1129    FunctionTemplate = FunctionTemplateDecl::Create(SemaRef.Context, DC,
1130                                                    Function->getLocation(),
1131                                                    Function->getDeclName(),
1132                                                    TemplateParams, Function);
1133    Function->setDescribedFunctionTemplate(FunctionTemplate);
1134
1135    FunctionTemplate->setLexicalDeclContext(LexicalDC);
1136
1137    if (isFriend && D->isThisDeclarationADefinition()) {
1138      // TODO: should we remember this connection regardless of whether
1139      // the friend declaration provided a body?
1140      FunctionTemplate->setInstantiatedFromMemberTemplate(
1141                                           D->getDescribedFunctionTemplate());
1142    }
1143  } else if (FunctionTemplate) {
1144    // Record this function template specialization.
1145    std::pair<const TemplateArgument *, unsigned> Innermost
1146      = TemplateArgs.getInnermost();
1147    Function->setFunctionTemplateSpecialization(FunctionTemplate,
1148                            TemplateArgumentList::CreateCopy(SemaRef.Context,
1149                                                             Innermost.first,
1150                                                             Innermost.second),
1151                                                InsertPos);
1152  } else if (isFriend && D->isThisDeclarationADefinition()) {
1153    // TODO: should we remember this connection regardless of whether
1154    // the friend declaration provided a body?
1155    Function->setInstantiationOfMemberFunction(D, TSK_ImplicitInstantiation);
1156  }
1157
1158  if (InitFunctionInstantiation(Function, D))
1159    Function->setInvalidDecl();
1160
1161  bool Redeclaration = false;
1162  bool isExplicitSpecialization = false;
1163
1164  LookupResult Previous(SemaRef, Function->getDeclName(), SourceLocation(),
1165                        Sema::LookupOrdinaryName, Sema::ForRedeclaration);
1166
1167  if (DependentFunctionTemplateSpecializationInfo *Info
1168        = D->getDependentSpecializationInfo()) {
1169    assert(isFriend && "non-friend has dependent specialization info?");
1170
1171    // This needs to be set now for future sanity.
1172    Function->setObjectOfFriendDecl(/*HasPrevious*/ true);
1173
1174    // Instantiate the explicit template arguments.
1175    TemplateArgumentListInfo ExplicitArgs(Info->getLAngleLoc(),
1176                                          Info->getRAngleLoc());
1177    if (SemaRef.Subst(Info->getTemplateArgs(), Info->getNumTemplateArgs(),
1178                      ExplicitArgs, TemplateArgs))
1179      return 0;
1180
1181    // Map the candidate templates to their instantiations.
1182    for (unsigned I = 0, E = Info->getNumTemplates(); I != E; ++I) {
1183      Decl *Temp = SemaRef.FindInstantiatedDecl(D->getLocation(),
1184                                                Info->getTemplate(I),
1185                                                TemplateArgs);
1186      if (!Temp) return 0;
1187
1188      Previous.addDecl(cast<FunctionTemplateDecl>(Temp));
1189    }
1190
1191    if (SemaRef.CheckFunctionTemplateSpecialization(Function,
1192                                                    &ExplicitArgs,
1193                                                    Previous))
1194      Function->setInvalidDecl();
1195
1196    isExplicitSpecialization = true;
1197
1198  } else if (TemplateParams || !FunctionTemplate) {
1199    // Look only into the namespace where the friend would be declared to
1200    // find a previous declaration. This is the innermost enclosing namespace,
1201    // as described in ActOnFriendFunctionDecl.
1202    SemaRef.LookupQualifiedName(Previous, DC);
1203
1204    // In C++, the previous declaration we find might be a tag type
1205    // (class or enum). In this case, the new declaration will hide the
1206    // tag type. Note that this does does not apply if we're declaring a
1207    // typedef (C++ [dcl.typedef]p4).
1208    if (Previous.isSingleTagDecl())
1209      Previous.clear();
1210  }
1211
1212  SemaRef.CheckFunctionDeclaration(/*Scope*/ 0, Function, Previous,
1213                                   isExplicitSpecialization, Redeclaration);
1214
1215  NamedDecl *PrincipalDecl = (TemplateParams
1216                              ? cast<NamedDecl>(FunctionTemplate)
1217                              : Function);
1218
1219  // If the original function was part of a friend declaration,
1220  // inherit its namespace state and add it to the owner.
1221  if (isFriend) {
1222    NamedDecl *PrevDecl;
1223    if (TemplateParams)
1224      PrevDecl = FunctionTemplate->getPreviousDeclaration();
1225    else
1226      PrevDecl = Function->getPreviousDeclaration();
1227
1228    PrincipalDecl->setObjectOfFriendDecl(PrevDecl != 0);
1229    DC->makeDeclVisibleInContext(PrincipalDecl, /*Recoverable=*/ false);
1230
1231    bool queuedInstantiation = false;
1232
1233    if (!SemaRef.getLangOptions().CPlusPlus0x &&
1234        D->isThisDeclarationADefinition()) {
1235      // Check for a function body.
1236      const FunctionDecl *Definition = 0;
1237      if (Function->isDefined(Definition) &&
1238          Definition->getTemplateSpecializationKind() == TSK_Undeclared) {
1239        SemaRef.Diag(Function->getLocation(), diag::err_redefinition)
1240          << Function->getDeclName();
1241        SemaRef.Diag(Definition->getLocation(), diag::note_previous_definition);
1242        Function->setInvalidDecl();
1243      }
1244      // Check for redefinitions due to other instantiations of this or
1245      // a similar friend function.
1246      else for (FunctionDecl::redecl_iterator R = Function->redecls_begin(),
1247                                           REnd = Function->redecls_end();
1248                R != REnd; ++R) {
1249        if (*R == Function)
1250          continue;
1251        switch (R->getFriendObjectKind()) {
1252        case Decl::FOK_None:
1253          if (!queuedInstantiation && R->isUsed(false)) {
1254            if (MemberSpecializationInfo *MSInfo
1255                = Function->getMemberSpecializationInfo()) {
1256              if (MSInfo->getPointOfInstantiation().isInvalid()) {
1257                SourceLocation Loc = R->getLocation(); // FIXME
1258                MSInfo->setPointOfInstantiation(Loc);
1259                SemaRef.PendingLocalImplicitInstantiations.push_back(
1260                                                 std::make_pair(Function, Loc));
1261                queuedInstantiation = true;
1262              }
1263            }
1264          }
1265          break;
1266        default:
1267          if (const FunctionDecl *RPattern
1268              = R->getTemplateInstantiationPattern())
1269            if (RPattern->isDefined(RPattern)) {
1270              SemaRef.Diag(Function->getLocation(), diag::err_redefinition)
1271                << Function->getDeclName();
1272              SemaRef.Diag(R->getLocation(), diag::note_previous_definition);
1273              Function->setInvalidDecl();
1274              break;
1275            }
1276        }
1277      }
1278    }
1279  }
1280
1281  if (Function->isOverloadedOperator() && !DC->isRecord() &&
1282      PrincipalDecl->isInIdentifierNamespace(Decl::IDNS_Ordinary))
1283    PrincipalDecl->setNonMemberOperator();
1284
1285  assert(!D->isDefaulted() && "only methods should be defaulted");
1286  return Function;
1287}
1288
1289Decl *
1290TemplateDeclInstantiator::VisitCXXMethodDecl(CXXMethodDecl *D,
1291                                      TemplateParameterList *TemplateParams) {
1292  FunctionTemplateDecl *FunctionTemplate = D->getDescribedFunctionTemplate();
1293  void *InsertPos = 0;
1294  if (FunctionTemplate && !TemplateParams) {
1295    // We are creating a function template specialization from a function
1296    // template. Check whether there is already a function template
1297    // specialization for this particular set of template arguments.
1298    std::pair<const TemplateArgument *, unsigned> Innermost
1299      = TemplateArgs.getInnermost();
1300
1301    FunctionDecl *SpecFunc
1302      = FunctionTemplate->findSpecialization(Innermost.first, Innermost.second,
1303                                             InsertPos);
1304
1305    // If we already have a function template specialization, return it.
1306    if (SpecFunc)
1307      return SpecFunc;
1308  }
1309
1310  bool isFriend;
1311  if (FunctionTemplate)
1312    isFriend = (FunctionTemplate->getFriendObjectKind() != Decl::FOK_None);
1313  else
1314    isFriend = (D->getFriendObjectKind() != Decl::FOK_None);
1315
1316  bool MergeWithParentScope = (TemplateParams != 0) ||
1317    !(isa<Decl>(Owner) &&
1318      cast<Decl>(Owner)->isDefinedOutsideFunctionOrMethod());
1319  LocalInstantiationScope Scope(SemaRef, MergeWithParentScope);
1320
1321  // Instantiate enclosing template arguments for friends.
1322  SmallVector<TemplateParameterList *, 4> TempParamLists;
1323  unsigned NumTempParamLists = 0;
1324  if (isFriend && (NumTempParamLists = D->getNumTemplateParameterLists())) {
1325    TempParamLists.set_size(NumTempParamLists);
1326    for (unsigned I = 0; I != NumTempParamLists; ++I) {
1327      TemplateParameterList *TempParams = D->getTemplateParameterList(I);
1328      TemplateParameterList *InstParams = SubstTemplateParams(TempParams);
1329      if (!InstParams)
1330        return NULL;
1331      TempParamLists[I] = InstParams;
1332    }
1333  }
1334
1335  SmallVector<ParmVarDecl *, 4> Params;
1336  TypeSourceInfo *TInfo = D->getTypeSourceInfo();
1337  TInfo = SubstFunctionType(D, Params);
1338  if (!TInfo)
1339    return 0;
1340  QualType T = TInfo->getType();
1341
1342  // \brief If the type of this function, after ignoring parentheses,
1343  // is not *directly* a function type, then we're instantiating a function
1344  // that was declared via a typedef, e.g.,
1345  //
1346  //   typedef int functype(int, int);
1347  //   functype func;
1348  //
1349  // In this case, we'll just go instantiate the ParmVarDecls that we
1350  // synthesized in the method declaration.
1351  if (!isa<FunctionProtoType>(T.IgnoreParens())) {
1352    assert(!Params.size() && "Instantiating type could not yield parameters");
1353    SmallVector<QualType, 4> ParamTypes;
1354    if (SemaRef.SubstParmTypes(D->getLocation(), D->param_begin(),
1355                               D->getNumParams(), TemplateArgs, ParamTypes,
1356                               &Params))
1357      return 0;
1358  }
1359
1360  NestedNameSpecifierLoc QualifierLoc = D->getQualifierLoc();
1361  if (QualifierLoc) {
1362    QualifierLoc = SemaRef.SubstNestedNameSpecifierLoc(QualifierLoc,
1363                                                 TemplateArgs);
1364    if (!QualifierLoc)
1365      return 0;
1366  }
1367
1368  DeclContext *DC = Owner;
1369  if (isFriend) {
1370    if (QualifierLoc) {
1371      CXXScopeSpec SS;
1372      SS.Adopt(QualifierLoc);
1373      DC = SemaRef.computeDeclContext(SS);
1374
1375      if (DC && SemaRef.RequireCompleteDeclContext(SS, DC))
1376        return 0;
1377    } else {
1378      DC = SemaRef.FindInstantiatedContext(D->getLocation(),
1379                                           D->getDeclContext(),
1380                                           TemplateArgs);
1381    }
1382    if (!DC) return 0;
1383  }
1384
1385  // Build the instantiated method declaration.
1386  CXXRecordDecl *Record = cast<CXXRecordDecl>(DC);
1387  CXXMethodDecl *Method = 0;
1388
1389  SourceLocation StartLoc = D->getInnerLocStart();
1390  DeclarationNameInfo NameInfo
1391    = SemaRef.SubstDeclarationNameInfo(D->getNameInfo(), TemplateArgs);
1392  if (CXXConstructorDecl *Constructor = dyn_cast<CXXConstructorDecl>(D)) {
1393    Method = CXXConstructorDecl::Create(SemaRef.Context, Record,
1394                                        StartLoc, NameInfo, T, TInfo,
1395                                        Constructor->isExplicit(),
1396                                        Constructor->isInlineSpecified(),
1397                                        false);
1398  } else if (CXXDestructorDecl *Destructor = dyn_cast<CXXDestructorDecl>(D)) {
1399    Method = CXXDestructorDecl::Create(SemaRef.Context, Record,
1400                                       StartLoc, NameInfo, T, TInfo,
1401                                       Destructor->isInlineSpecified(),
1402                                       false);
1403  } else if (CXXConversionDecl *Conversion = dyn_cast<CXXConversionDecl>(D)) {
1404    Method = CXXConversionDecl::Create(SemaRef.Context, Record,
1405                                       StartLoc, NameInfo, T, TInfo,
1406                                       Conversion->isInlineSpecified(),
1407                                       Conversion->isExplicit(),
1408                                       Conversion->getLocEnd());
1409  } else {
1410    Method = CXXMethodDecl::Create(SemaRef.Context, Record,
1411                                   StartLoc, NameInfo, T, TInfo,
1412                                   D->isStatic(),
1413                                   D->getStorageClassAsWritten(),
1414                                   D->isInlineSpecified(),
1415                                   D->getLocEnd());
1416  }
1417
1418  if (QualifierLoc)
1419    Method->setQualifierInfo(QualifierLoc);
1420
1421  if (TemplateParams) {
1422    // Our resulting instantiation is actually a function template, since we
1423    // are substituting only the outer template parameters. For example, given
1424    //
1425    //   template<typename T>
1426    //   struct X {
1427    //     template<typename U> void f(T, U);
1428    //   };
1429    //
1430    //   X<int> x;
1431    //
1432    // We are instantiating the member template "f" within X<int>, which means
1433    // substituting int for T, but leaving "f" as a member function template.
1434    // Build the function template itself.
1435    FunctionTemplate = FunctionTemplateDecl::Create(SemaRef.Context, Record,
1436                                                    Method->getLocation(),
1437                                                    Method->getDeclName(),
1438                                                    TemplateParams, Method);
1439    if (isFriend) {
1440      FunctionTemplate->setLexicalDeclContext(Owner);
1441      FunctionTemplate->setObjectOfFriendDecl(true);
1442    } else if (D->isOutOfLine())
1443      FunctionTemplate->setLexicalDeclContext(D->getLexicalDeclContext());
1444    Method->setDescribedFunctionTemplate(FunctionTemplate);
1445  } else if (FunctionTemplate) {
1446    // Record this function template specialization.
1447    std::pair<const TemplateArgument *, unsigned> Innermost
1448      = TemplateArgs.getInnermost();
1449    Method->setFunctionTemplateSpecialization(FunctionTemplate,
1450                         TemplateArgumentList::CreateCopy(SemaRef.Context,
1451                                                          Innermost.first,
1452                                                          Innermost.second),
1453                                              InsertPos);
1454  } else if (!isFriend) {
1455    // Record that this is an instantiation of a member function.
1456    Method->setInstantiationOfMemberFunction(D, TSK_ImplicitInstantiation);
1457  }
1458
1459  // If we are instantiating a member function defined
1460  // out-of-line, the instantiation will have the same lexical
1461  // context (which will be a namespace scope) as the template.
1462  if (isFriend) {
1463    if (NumTempParamLists)
1464      Method->setTemplateParameterListsInfo(SemaRef.Context,
1465                                            NumTempParamLists,
1466                                            TempParamLists.data());
1467
1468    Method->setLexicalDeclContext(Owner);
1469    Method->setObjectOfFriendDecl(true);
1470  } else if (D->isOutOfLine())
1471    Method->setLexicalDeclContext(D->getLexicalDeclContext());
1472
1473  // Attach the parameters
1474  for (unsigned P = 0; P < Params.size(); ++P)
1475    Params[P]->setOwningFunction(Method);
1476  Method->setParams(Params.data(), Params.size());
1477
1478  if (InitMethodInstantiation(Method, D))
1479    Method->setInvalidDecl();
1480
1481  LookupResult Previous(SemaRef, NameInfo, Sema::LookupOrdinaryName,
1482                        Sema::ForRedeclaration);
1483
1484  if (!FunctionTemplate || TemplateParams || isFriend) {
1485    SemaRef.LookupQualifiedName(Previous, Record);
1486
1487    // In C++, the previous declaration we find might be a tag type
1488    // (class or enum). In this case, the new declaration will hide the
1489    // tag type. Note that this does does not apply if we're declaring a
1490    // typedef (C++ [dcl.typedef]p4).
1491    if (Previous.isSingleTagDecl())
1492      Previous.clear();
1493  }
1494
1495  bool Redeclaration = false;
1496  SemaRef.CheckFunctionDeclaration(0, Method, Previous, false, Redeclaration);
1497
1498  if (D->isPure())
1499    SemaRef.CheckPureMethod(Method, SourceRange());
1500
1501  Method->setAccess(D->getAccess());
1502
1503  SemaRef.CheckOverrideControl(Method);
1504
1505  if (FunctionTemplate) {
1506    // If there's a function template, let our caller handle it.
1507  } else if (Method->isInvalidDecl() && !Previous.empty()) {
1508    // Don't hide a (potentially) valid declaration with an invalid one.
1509  } else {
1510    NamedDecl *DeclToAdd = (TemplateParams
1511                            ? cast<NamedDecl>(FunctionTemplate)
1512                            : Method);
1513    if (isFriend)
1514      Record->makeDeclVisibleInContext(DeclToAdd);
1515    else
1516      Owner->addDecl(DeclToAdd);
1517  }
1518
1519  if (D->isExplicitlyDefaulted()) {
1520    SemaRef.SetDeclDefaulted(Method, Method->getLocation());
1521  } else {
1522    assert(!D->isDefaulted() &&
1523           "should not implicitly default uninstantiated function");
1524  }
1525
1526  return Method;
1527}
1528
1529Decl *TemplateDeclInstantiator::VisitCXXConstructorDecl(CXXConstructorDecl *D) {
1530  return VisitCXXMethodDecl(D);
1531}
1532
1533Decl *TemplateDeclInstantiator::VisitCXXDestructorDecl(CXXDestructorDecl *D) {
1534  return VisitCXXMethodDecl(D);
1535}
1536
1537Decl *TemplateDeclInstantiator::VisitCXXConversionDecl(CXXConversionDecl *D) {
1538  return VisitCXXMethodDecl(D);
1539}
1540
1541ParmVarDecl *TemplateDeclInstantiator::VisitParmVarDecl(ParmVarDecl *D) {
1542  return SemaRef.SubstParmVarDecl(D, TemplateArgs, /*indexAdjustment*/ 0,
1543                                  llvm::Optional<unsigned>());
1544}
1545
1546Decl *TemplateDeclInstantiator::VisitTemplateTypeParmDecl(
1547                                                    TemplateTypeParmDecl *D) {
1548  // TODO: don't always clone when decls are refcounted.
1549  assert(D->getTypeForDecl()->isTemplateTypeParmType());
1550
1551  TemplateTypeParmDecl *Inst =
1552    TemplateTypeParmDecl::Create(SemaRef.Context, Owner,
1553                                 D->getLocStart(), D->getLocation(),
1554                                 D->getDepth() - TemplateArgs.getNumLevels(),
1555                                 D->getIndex(), D->getIdentifier(),
1556                                 D->wasDeclaredWithTypename(),
1557                                 D->isParameterPack());
1558  Inst->setAccess(AS_public);
1559
1560  if (D->hasDefaultArgument())
1561    Inst->setDefaultArgument(D->getDefaultArgumentInfo(), false);
1562
1563  // Introduce this template parameter's instantiation into the instantiation
1564  // scope.
1565  SemaRef.CurrentInstantiationScope->InstantiatedLocal(D, Inst);
1566
1567  return Inst;
1568}
1569
1570Decl *TemplateDeclInstantiator::VisitNonTypeTemplateParmDecl(
1571                                                 NonTypeTemplateParmDecl *D) {
1572  // Substitute into the type of the non-type template parameter.
1573  TypeLoc TL = D->getTypeSourceInfo()->getTypeLoc();
1574  SmallVector<TypeSourceInfo *, 4> ExpandedParameterPackTypesAsWritten;
1575  SmallVector<QualType, 4> ExpandedParameterPackTypes;
1576  bool IsExpandedParameterPack = false;
1577  TypeSourceInfo *DI;
1578  QualType T;
1579  bool Invalid = false;
1580
1581  if (D->isExpandedParameterPack()) {
1582    // The non-type template parameter pack is an already-expanded pack
1583    // expansion of types. Substitute into each of the expanded types.
1584    ExpandedParameterPackTypes.reserve(D->getNumExpansionTypes());
1585    ExpandedParameterPackTypesAsWritten.reserve(D->getNumExpansionTypes());
1586    for (unsigned I = 0, N = D->getNumExpansionTypes(); I != N; ++I) {
1587      TypeSourceInfo *NewDI =SemaRef.SubstType(D->getExpansionTypeSourceInfo(I),
1588                                               TemplateArgs,
1589                                               D->getLocation(),
1590                                               D->getDeclName());
1591      if (!NewDI)
1592        return 0;
1593
1594      ExpandedParameterPackTypesAsWritten.push_back(NewDI);
1595      QualType NewT =SemaRef.CheckNonTypeTemplateParameterType(NewDI->getType(),
1596                                                              D->getLocation());
1597      if (NewT.isNull())
1598        return 0;
1599      ExpandedParameterPackTypes.push_back(NewT);
1600    }
1601
1602    IsExpandedParameterPack = true;
1603    DI = D->getTypeSourceInfo();
1604    T = DI->getType();
1605  } else if (isa<PackExpansionTypeLoc>(TL)) {
1606    // The non-type template parameter pack's type is a pack expansion of types.
1607    // Determine whether we need to expand this parameter pack into separate
1608    // types.
1609    PackExpansionTypeLoc Expansion = cast<PackExpansionTypeLoc>(TL);
1610    TypeLoc Pattern = Expansion.getPatternLoc();
1611    SmallVector<UnexpandedParameterPack, 2> Unexpanded;
1612    SemaRef.collectUnexpandedParameterPacks(Pattern, Unexpanded);
1613
1614    // Determine whether the set of unexpanded parameter packs can and should
1615    // be expanded.
1616    bool Expand = true;
1617    bool RetainExpansion = false;
1618    llvm::Optional<unsigned> OrigNumExpansions
1619      = Expansion.getTypePtr()->getNumExpansions();
1620    llvm::Optional<unsigned> NumExpansions = OrigNumExpansions;
1621    if (SemaRef.CheckParameterPacksForExpansion(Expansion.getEllipsisLoc(),
1622                                                Pattern.getSourceRange(),
1623                                                Unexpanded.data(),
1624                                                Unexpanded.size(),
1625                                                TemplateArgs,
1626                                                Expand, RetainExpansion,
1627                                                NumExpansions))
1628      return 0;
1629
1630    if (Expand) {
1631      for (unsigned I = 0; I != *NumExpansions; ++I) {
1632        Sema::ArgumentPackSubstitutionIndexRAII SubstIndex(SemaRef, I);
1633        TypeSourceInfo *NewDI = SemaRef.SubstType(Pattern, TemplateArgs,
1634                                                  D->getLocation(),
1635                                                  D->getDeclName());
1636        if (!NewDI)
1637          return 0;
1638
1639        ExpandedParameterPackTypesAsWritten.push_back(NewDI);
1640        QualType NewT = SemaRef.CheckNonTypeTemplateParameterType(
1641                                                              NewDI->getType(),
1642                                                              D->getLocation());
1643        if (NewT.isNull())
1644          return 0;
1645        ExpandedParameterPackTypes.push_back(NewT);
1646      }
1647
1648      // Note that we have an expanded parameter pack. The "type" of this
1649      // expanded parameter pack is the original expansion type, but callers
1650      // will end up using the expanded parameter pack types for type-checking.
1651      IsExpandedParameterPack = true;
1652      DI = D->getTypeSourceInfo();
1653      T = DI->getType();
1654    } else {
1655      // We cannot fully expand the pack expansion now, so substitute into the
1656      // pattern and create a new pack expansion type.
1657      Sema::ArgumentPackSubstitutionIndexRAII SubstIndex(SemaRef, -1);
1658      TypeSourceInfo *NewPattern = SemaRef.SubstType(Pattern, TemplateArgs,
1659                                                     D->getLocation(),
1660                                                     D->getDeclName());
1661      if (!NewPattern)
1662        return 0;
1663
1664      DI = SemaRef.CheckPackExpansion(NewPattern, Expansion.getEllipsisLoc(),
1665                                      NumExpansions);
1666      if (!DI)
1667        return 0;
1668
1669      T = DI->getType();
1670    }
1671  } else {
1672    // Simple case: substitution into a parameter that is not a parameter pack.
1673    DI = SemaRef.SubstType(D->getTypeSourceInfo(), TemplateArgs,
1674                           D->getLocation(), D->getDeclName());
1675    if (!DI)
1676      return 0;
1677
1678    // Check that this type is acceptable for a non-type template parameter.
1679    T = SemaRef.CheckNonTypeTemplateParameterType(DI->getType(),
1680                                                  D->getLocation());
1681    if (T.isNull()) {
1682      T = SemaRef.Context.IntTy;
1683      Invalid = true;
1684    }
1685  }
1686
1687  NonTypeTemplateParmDecl *Param;
1688  if (IsExpandedParameterPack)
1689    Param = NonTypeTemplateParmDecl::Create(SemaRef.Context, Owner,
1690                                            D->getInnerLocStart(),
1691                                            D->getLocation(),
1692                                    D->getDepth() - TemplateArgs.getNumLevels(),
1693                                            D->getPosition(),
1694                                            D->getIdentifier(), T,
1695                                            DI,
1696                                            ExpandedParameterPackTypes.data(),
1697                                            ExpandedParameterPackTypes.size(),
1698                                    ExpandedParameterPackTypesAsWritten.data());
1699  else
1700    Param = NonTypeTemplateParmDecl::Create(SemaRef.Context, Owner,
1701                                            D->getInnerLocStart(),
1702                                            D->getLocation(),
1703                                    D->getDepth() - TemplateArgs.getNumLevels(),
1704                                            D->getPosition(),
1705                                            D->getIdentifier(), T,
1706                                            D->isParameterPack(), DI);
1707
1708  Param->setAccess(AS_public);
1709  if (Invalid)
1710    Param->setInvalidDecl();
1711
1712  Param->setDefaultArgument(D->getDefaultArgument(), false);
1713
1714  // Introduce this template parameter's instantiation into the instantiation
1715  // scope.
1716  SemaRef.CurrentInstantiationScope->InstantiatedLocal(D, Param);
1717  return Param;
1718}
1719
1720Decl *
1721TemplateDeclInstantiator::VisitTemplateTemplateParmDecl(
1722                                                  TemplateTemplateParmDecl *D) {
1723  // Instantiate the template parameter list of the template template parameter.
1724  TemplateParameterList *TempParams = D->getTemplateParameters();
1725  TemplateParameterList *InstParams;
1726  {
1727    // Perform the actual substitution of template parameters within a new,
1728    // local instantiation scope.
1729    LocalInstantiationScope Scope(SemaRef);
1730    InstParams = SubstTemplateParams(TempParams);
1731    if (!InstParams)
1732      return NULL;
1733  }
1734
1735  // Build the template template parameter.
1736  TemplateTemplateParmDecl *Param
1737    = TemplateTemplateParmDecl::Create(SemaRef.Context, Owner, D->getLocation(),
1738                                   D->getDepth() - TemplateArgs.getNumLevels(),
1739                                       D->getPosition(), D->isParameterPack(),
1740                                       D->getIdentifier(), InstParams);
1741  Param->setDefaultArgument(D->getDefaultArgument(), false);
1742  Param->setAccess(AS_public);
1743
1744  // Introduce this template parameter's instantiation into the instantiation
1745  // scope.
1746  SemaRef.CurrentInstantiationScope->InstantiatedLocal(D, Param);
1747
1748  return Param;
1749}
1750
1751Decl *TemplateDeclInstantiator::VisitUsingDirectiveDecl(UsingDirectiveDecl *D) {
1752  // Using directives are never dependent (and never contain any types or
1753  // expressions), so they require no explicit instantiation work.
1754
1755  UsingDirectiveDecl *Inst
1756    = UsingDirectiveDecl::Create(SemaRef.Context, Owner, D->getLocation(),
1757                                 D->getNamespaceKeyLocation(),
1758                                 D->getQualifierLoc(),
1759                                 D->getIdentLocation(),
1760                                 D->getNominatedNamespace(),
1761                                 D->getCommonAncestor());
1762  Owner->addDecl(Inst);
1763  return Inst;
1764}
1765
1766Decl *TemplateDeclInstantiator::VisitUsingDecl(UsingDecl *D) {
1767
1768  // The nested name specifier may be dependent, for example
1769  //     template <typename T> struct t {
1770  //       struct s1 { T f1(); };
1771  //       struct s2 : s1 { using s1::f1; };
1772  //     };
1773  //     template struct t<int>;
1774  // Here, in using s1::f1, s1 refers to t<T>::s1;
1775  // we need to substitute for t<int>::s1.
1776  NestedNameSpecifierLoc QualifierLoc
1777    = SemaRef.SubstNestedNameSpecifierLoc(D->getQualifierLoc(),
1778                                          TemplateArgs);
1779  if (!QualifierLoc)
1780    return 0;
1781
1782  // The name info is non-dependent, so no transformation
1783  // is required.
1784  DeclarationNameInfo NameInfo = D->getNameInfo();
1785
1786  // We only need to do redeclaration lookups if we're in a class
1787  // scope (in fact, it's not really even possible in non-class
1788  // scopes).
1789  bool CheckRedeclaration = Owner->isRecord();
1790
1791  LookupResult Prev(SemaRef, NameInfo, Sema::LookupUsingDeclName,
1792                    Sema::ForRedeclaration);
1793
1794  UsingDecl *NewUD = UsingDecl::Create(SemaRef.Context, Owner,
1795                                       D->getUsingLocation(),
1796                                       QualifierLoc,
1797                                       NameInfo,
1798                                       D->isTypeName());
1799
1800  CXXScopeSpec SS;
1801  SS.Adopt(QualifierLoc);
1802  if (CheckRedeclaration) {
1803    Prev.setHideTags(false);
1804    SemaRef.LookupQualifiedName(Prev, Owner);
1805
1806    // Check for invalid redeclarations.
1807    if (SemaRef.CheckUsingDeclRedeclaration(D->getUsingLocation(),
1808                                            D->isTypeName(), SS,
1809                                            D->getLocation(), Prev))
1810      NewUD->setInvalidDecl();
1811
1812  }
1813
1814  if (!NewUD->isInvalidDecl() &&
1815      SemaRef.CheckUsingDeclQualifier(D->getUsingLocation(), SS,
1816                                      D->getLocation()))
1817    NewUD->setInvalidDecl();
1818
1819  SemaRef.Context.setInstantiatedFromUsingDecl(NewUD, D);
1820  NewUD->setAccess(D->getAccess());
1821  Owner->addDecl(NewUD);
1822
1823  // Don't process the shadow decls for an invalid decl.
1824  if (NewUD->isInvalidDecl())
1825    return NewUD;
1826
1827  bool isFunctionScope = Owner->isFunctionOrMethod();
1828
1829  // Process the shadow decls.
1830  for (UsingDecl::shadow_iterator I = D->shadow_begin(), E = D->shadow_end();
1831         I != E; ++I) {
1832    UsingShadowDecl *Shadow = *I;
1833    NamedDecl *InstTarget =
1834      cast_or_null<NamedDecl>(SemaRef.FindInstantiatedDecl(
1835                                                          Shadow->getLocation(),
1836                                                        Shadow->getTargetDecl(),
1837                                                           TemplateArgs));
1838    if (!InstTarget)
1839      return 0;
1840
1841    if (CheckRedeclaration &&
1842        SemaRef.CheckUsingShadowDecl(NewUD, InstTarget, Prev))
1843      continue;
1844
1845    UsingShadowDecl *InstShadow
1846      = SemaRef.BuildUsingShadowDecl(/*Scope*/ 0, NewUD, InstTarget);
1847    SemaRef.Context.setInstantiatedFromUsingShadowDecl(InstShadow, Shadow);
1848
1849    if (isFunctionScope)
1850      SemaRef.CurrentInstantiationScope->InstantiatedLocal(Shadow, InstShadow);
1851  }
1852
1853  return NewUD;
1854}
1855
1856Decl *TemplateDeclInstantiator::VisitUsingShadowDecl(UsingShadowDecl *D) {
1857  // Ignore these;  we handle them in bulk when processing the UsingDecl.
1858  return 0;
1859}
1860
1861Decl * TemplateDeclInstantiator
1862    ::VisitUnresolvedUsingTypenameDecl(UnresolvedUsingTypenameDecl *D) {
1863  NestedNameSpecifierLoc QualifierLoc
1864    = SemaRef.SubstNestedNameSpecifierLoc(D->getQualifierLoc(),
1865                                          TemplateArgs);
1866  if (!QualifierLoc)
1867    return 0;
1868
1869  CXXScopeSpec SS;
1870  SS.Adopt(QualifierLoc);
1871
1872  // Since NameInfo refers to a typename, it cannot be a C++ special name.
1873  // Hence, no tranformation is required for it.
1874  DeclarationNameInfo NameInfo(D->getDeclName(), D->getLocation());
1875  NamedDecl *UD =
1876    SemaRef.BuildUsingDeclaration(/*Scope*/ 0, D->getAccess(),
1877                                  D->getUsingLoc(), SS, NameInfo, 0,
1878                                  /*instantiation*/ true,
1879                                  /*typename*/ true, D->getTypenameLoc());
1880  if (UD)
1881    SemaRef.Context.setInstantiatedFromUsingDecl(cast<UsingDecl>(UD), D);
1882
1883  return UD;
1884}
1885
1886Decl * TemplateDeclInstantiator
1887    ::VisitUnresolvedUsingValueDecl(UnresolvedUsingValueDecl *D) {
1888  NestedNameSpecifierLoc QualifierLoc
1889      = SemaRef.SubstNestedNameSpecifierLoc(D->getQualifierLoc(), TemplateArgs);
1890  if (!QualifierLoc)
1891    return 0;
1892
1893  CXXScopeSpec SS;
1894  SS.Adopt(QualifierLoc);
1895
1896  DeclarationNameInfo NameInfo
1897    = SemaRef.SubstDeclarationNameInfo(D->getNameInfo(), TemplateArgs);
1898
1899  NamedDecl *UD =
1900    SemaRef.BuildUsingDeclaration(/*Scope*/ 0, D->getAccess(),
1901                                  D->getUsingLoc(), SS, NameInfo, 0,
1902                                  /*instantiation*/ true,
1903                                  /*typename*/ false, SourceLocation());
1904  if (UD)
1905    SemaRef.Context.setInstantiatedFromUsingDecl(cast<UsingDecl>(UD), D);
1906
1907  return UD;
1908}
1909
1910Decl *Sema::SubstDecl(Decl *D, DeclContext *Owner,
1911                      const MultiLevelTemplateArgumentList &TemplateArgs) {
1912  TemplateDeclInstantiator Instantiator(*this, Owner, TemplateArgs);
1913  if (D->isInvalidDecl())
1914    return 0;
1915
1916  return Instantiator.Visit(D);
1917}
1918
1919/// \brief Instantiates a nested template parameter list in the current
1920/// instantiation context.
1921///
1922/// \param L The parameter list to instantiate
1923///
1924/// \returns NULL if there was an error
1925TemplateParameterList *
1926TemplateDeclInstantiator::SubstTemplateParams(TemplateParameterList *L) {
1927  // Get errors for all the parameters before bailing out.
1928  bool Invalid = false;
1929
1930  unsigned N = L->size();
1931  typedef SmallVector<NamedDecl *, 8> ParamVector;
1932  ParamVector Params;
1933  Params.reserve(N);
1934  for (TemplateParameterList::iterator PI = L->begin(), PE = L->end();
1935       PI != PE; ++PI) {
1936    NamedDecl *D = cast_or_null<NamedDecl>(Visit(*PI));
1937    Params.push_back(D);
1938    Invalid = Invalid || !D || D->isInvalidDecl();
1939  }
1940
1941  // Clean up if we had an error.
1942  if (Invalid)
1943    return NULL;
1944
1945  TemplateParameterList *InstL
1946    = TemplateParameterList::Create(SemaRef.Context, L->getTemplateLoc(),
1947                                    L->getLAngleLoc(), &Params.front(), N,
1948                                    L->getRAngleLoc());
1949  return InstL;
1950}
1951
1952/// \brief Instantiate the declaration of a class template partial
1953/// specialization.
1954///
1955/// \param ClassTemplate the (instantiated) class template that is partially
1956// specialized by the instantiation of \p PartialSpec.
1957///
1958/// \param PartialSpec the (uninstantiated) class template partial
1959/// specialization that we are instantiating.
1960///
1961/// \returns The instantiated partial specialization, if successful; otherwise,
1962/// NULL to indicate an error.
1963ClassTemplatePartialSpecializationDecl *
1964TemplateDeclInstantiator::InstantiateClassTemplatePartialSpecialization(
1965                                            ClassTemplateDecl *ClassTemplate,
1966                          ClassTemplatePartialSpecializationDecl *PartialSpec) {
1967  // Create a local instantiation scope for this class template partial
1968  // specialization, which will contain the instantiations of the template
1969  // parameters.
1970  LocalInstantiationScope Scope(SemaRef);
1971
1972  // Substitute into the template parameters of the class template partial
1973  // specialization.
1974  TemplateParameterList *TempParams = PartialSpec->getTemplateParameters();
1975  TemplateParameterList *InstParams = SubstTemplateParams(TempParams);
1976  if (!InstParams)
1977    return 0;
1978
1979  // Substitute into the template arguments of the class template partial
1980  // specialization.
1981  TemplateArgumentListInfo InstTemplateArgs; // no angle locations
1982  if (SemaRef.Subst(PartialSpec->getTemplateArgsAsWritten(),
1983                    PartialSpec->getNumTemplateArgsAsWritten(),
1984                    InstTemplateArgs, TemplateArgs))
1985    return 0;
1986
1987  // Check that the template argument list is well-formed for this
1988  // class template.
1989  SmallVector<TemplateArgument, 4> Converted;
1990  if (SemaRef.CheckTemplateArgumentList(ClassTemplate,
1991                                        PartialSpec->getLocation(),
1992                                        InstTemplateArgs,
1993                                        false,
1994                                        Converted))
1995    return 0;
1996
1997  // Figure out where to insert this class template partial specialization
1998  // in the member template's set of class template partial specializations.
1999  void *InsertPos = 0;
2000  ClassTemplateSpecializationDecl *PrevDecl
2001    = ClassTemplate->findPartialSpecialization(Converted.data(),
2002                                               Converted.size(), InsertPos);
2003
2004  // Build the canonical type that describes the converted template
2005  // arguments of the class template partial specialization.
2006  QualType CanonType
2007    = SemaRef.Context.getTemplateSpecializationType(TemplateName(ClassTemplate),
2008                                                    Converted.data(),
2009                                                    Converted.size());
2010
2011  // Build the fully-sugared type for this class template
2012  // specialization as the user wrote in the specialization
2013  // itself. This means that we'll pretty-print the type retrieved
2014  // from the specialization's declaration the way that the user
2015  // actually wrote the specialization, rather than formatting the
2016  // name based on the "canonical" representation used to store the
2017  // template arguments in the specialization.
2018  TypeSourceInfo *WrittenTy
2019    = SemaRef.Context.getTemplateSpecializationTypeInfo(
2020                                                    TemplateName(ClassTemplate),
2021                                                    PartialSpec->getLocation(),
2022                                                    InstTemplateArgs,
2023                                                    CanonType);
2024
2025  if (PrevDecl) {
2026    // We've already seen a partial specialization with the same template
2027    // parameters and template arguments. This can happen, for example, when
2028    // substituting the outer template arguments ends up causing two
2029    // class template partial specializations of a member class template
2030    // to have identical forms, e.g.,
2031    //
2032    //   template<typename T, typename U>
2033    //   struct Outer {
2034    //     template<typename X, typename Y> struct Inner;
2035    //     template<typename Y> struct Inner<T, Y>;
2036    //     template<typename Y> struct Inner<U, Y>;
2037    //   };
2038    //
2039    //   Outer<int, int> outer; // error: the partial specializations of Inner
2040    //                          // have the same signature.
2041    SemaRef.Diag(PartialSpec->getLocation(), diag::err_partial_spec_redeclared)
2042      << WrittenTy->getType();
2043    SemaRef.Diag(PrevDecl->getLocation(), diag::note_prev_partial_spec_here)
2044      << SemaRef.Context.getTypeDeclType(PrevDecl);
2045    return 0;
2046  }
2047
2048
2049  // Create the class template partial specialization declaration.
2050  ClassTemplatePartialSpecializationDecl *InstPartialSpec
2051    = ClassTemplatePartialSpecializationDecl::Create(SemaRef.Context,
2052                                                     PartialSpec->getTagKind(),
2053                                                     Owner,
2054                                                     PartialSpec->getLocStart(),
2055                                                     PartialSpec->getLocation(),
2056                                                     InstParams,
2057                                                     ClassTemplate,
2058                                                     Converted.data(),
2059                                                     Converted.size(),
2060                                                     InstTemplateArgs,
2061                                                     CanonType,
2062                                                     0,
2063                             ClassTemplate->getNextPartialSpecSequenceNumber());
2064  // Substitute the nested name specifier, if any.
2065  if (SubstQualifier(PartialSpec, InstPartialSpec))
2066    return 0;
2067
2068  InstPartialSpec->setInstantiatedFromMember(PartialSpec);
2069  InstPartialSpec->setTypeAsWritten(WrittenTy);
2070
2071  // Add this partial specialization to the set of class template partial
2072  // specializations.
2073  ClassTemplate->AddPartialSpecialization(InstPartialSpec, InsertPos);
2074  return InstPartialSpec;
2075}
2076
2077TypeSourceInfo*
2078TemplateDeclInstantiator::SubstFunctionType(FunctionDecl *D,
2079                              SmallVectorImpl<ParmVarDecl *> &Params) {
2080  TypeSourceInfo *OldTInfo = D->getTypeSourceInfo();
2081  assert(OldTInfo && "substituting function without type source info");
2082  assert(Params.empty() && "parameter vector is non-empty at start");
2083  TypeSourceInfo *NewTInfo
2084    = SemaRef.SubstFunctionDeclType(OldTInfo, TemplateArgs,
2085                                    D->getTypeSpecStartLoc(),
2086                                    D->getDeclName());
2087  if (!NewTInfo)
2088    return 0;
2089
2090  if (NewTInfo != OldTInfo) {
2091    // Get parameters from the new type info.
2092    TypeLoc OldTL = OldTInfo->getTypeLoc().IgnoreParens();
2093    if (FunctionProtoTypeLoc *OldProtoLoc
2094                                  = dyn_cast<FunctionProtoTypeLoc>(&OldTL)) {
2095      TypeLoc NewTL = NewTInfo->getTypeLoc().IgnoreParens();
2096      FunctionProtoTypeLoc *NewProtoLoc = cast<FunctionProtoTypeLoc>(&NewTL);
2097      assert(NewProtoLoc && "Missing prototype?");
2098      unsigned NewIdx = 0, NumNewParams = NewProtoLoc->getNumArgs();
2099      for (unsigned OldIdx = 0, NumOldParams = OldProtoLoc->getNumArgs();
2100           OldIdx != NumOldParams; ++OldIdx) {
2101        ParmVarDecl *OldParam = OldProtoLoc->getArg(OldIdx);
2102        if (!OldParam->isParameterPack() ||
2103            (NewIdx < NumNewParams &&
2104             NewProtoLoc->getArg(NewIdx)->isParameterPack())) {
2105          // Simple case: normal parameter, or a parameter pack that's
2106          // instantiated to a (still-dependent) parameter pack.
2107          ParmVarDecl *NewParam = NewProtoLoc->getArg(NewIdx++);
2108          Params.push_back(NewParam);
2109          SemaRef.CurrentInstantiationScope->InstantiatedLocal(OldParam,
2110                                                               NewParam);
2111          continue;
2112        }
2113
2114        // Parameter pack: make the instantiation an argument pack.
2115        SemaRef.CurrentInstantiationScope->MakeInstantiatedLocalArgPack(
2116                                                                      OldParam);
2117        unsigned NumArgumentsInExpansion
2118          = SemaRef.getNumArgumentsInExpansion(OldParam->getType(),
2119                                               TemplateArgs);
2120        while (NumArgumentsInExpansion--) {
2121          ParmVarDecl *NewParam = NewProtoLoc->getArg(NewIdx++);
2122          Params.push_back(NewParam);
2123          SemaRef.CurrentInstantiationScope->InstantiatedLocalPackArg(OldParam,
2124                                                                      NewParam);
2125        }
2126      }
2127    }
2128  } else {
2129    // The function type itself was not dependent and therefore no
2130    // substitution occurred. However, we still need to instantiate
2131    // the function parameters themselves.
2132    TypeLoc OldTL = OldTInfo->getTypeLoc().IgnoreParens();
2133    if (FunctionProtoTypeLoc *OldProtoLoc
2134                                    = dyn_cast<FunctionProtoTypeLoc>(&OldTL)) {
2135      for (unsigned i = 0, i_end = OldProtoLoc->getNumArgs(); i != i_end; ++i) {
2136        ParmVarDecl *Parm = VisitParmVarDecl(OldProtoLoc->getArg(i));
2137        if (!Parm)
2138          return 0;
2139        Params.push_back(Parm);
2140      }
2141    }
2142  }
2143  return NewTInfo;
2144}
2145
2146/// \brief Initializes the common fields of an instantiation function
2147/// declaration (New) from the corresponding fields of its template (Tmpl).
2148///
2149/// \returns true if there was an error
2150bool
2151TemplateDeclInstantiator::InitFunctionInstantiation(FunctionDecl *New,
2152                                                    FunctionDecl *Tmpl) {
2153  if (Tmpl->isDeletedAsWritten())
2154    New->setDeletedAsWritten();
2155
2156  // If we are performing substituting explicitly-specified template arguments
2157  // or deduced template arguments into a function template and we reach this
2158  // point, we are now past the point where SFINAE applies and have committed
2159  // to keeping the new function template specialization. We therefore
2160  // convert the active template instantiation for the function template
2161  // into a template instantiation for this specific function template
2162  // specialization, which is not a SFINAE context, so that we diagnose any
2163  // further errors in the declaration itself.
2164  typedef Sema::ActiveTemplateInstantiation ActiveInstType;
2165  ActiveInstType &ActiveInst = SemaRef.ActiveTemplateInstantiations.back();
2166  if (ActiveInst.Kind == ActiveInstType::ExplicitTemplateArgumentSubstitution ||
2167      ActiveInst.Kind == ActiveInstType::DeducedTemplateArgumentSubstitution) {
2168    if (FunctionTemplateDecl *FunTmpl
2169          = dyn_cast<FunctionTemplateDecl>((Decl *)ActiveInst.Entity)) {
2170      assert(FunTmpl->getTemplatedDecl() == Tmpl &&
2171             "Deduction from the wrong function template?");
2172      (void) FunTmpl;
2173      ActiveInst.Kind = ActiveInstType::TemplateInstantiation;
2174      ActiveInst.Entity = reinterpret_cast<uintptr_t>(New);
2175      --SemaRef.NonInstantiationEntries;
2176    }
2177  }
2178
2179  const FunctionProtoType *Proto = Tmpl->getType()->getAs<FunctionProtoType>();
2180  assert(Proto && "Function template without prototype?");
2181
2182  if (Proto->hasExceptionSpec() || Proto->getNoReturnAttr()) {
2183    // The function has an exception specification or a "noreturn"
2184    // attribute. Substitute into each of the exception types.
2185    SmallVector<QualType, 4> Exceptions;
2186    for (unsigned I = 0, N = Proto->getNumExceptions(); I != N; ++I) {
2187      // FIXME: Poor location information!
2188      if (const PackExpansionType *PackExpansion
2189            = Proto->getExceptionType(I)->getAs<PackExpansionType>()) {
2190        // We have a pack expansion. Instantiate it.
2191        SmallVector<UnexpandedParameterPack, 2> Unexpanded;
2192        SemaRef.collectUnexpandedParameterPacks(PackExpansion->getPattern(),
2193                                                Unexpanded);
2194        assert(!Unexpanded.empty() &&
2195               "Pack expansion without parameter packs?");
2196
2197        bool Expand = false;
2198        bool RetainExpansion = false;
2199        llvm::Optional<unsigned> NumExpansions
2200                                          = PackExpansion->getNumExpansions();
2201        if (SemaRef.CheckParameterPacksForExpansion(New->getLocation(),
2202                                                    SourceRange(),
2203                                                    Unexpanded.data(),
2204                                                    Unexpanded.size(),
2205                                                    TemplateArgs,
2206                                                    Expand,
2207                                                    RetainExpansion,
2208                                                    NumExpansions))
2209          break;
2210
2211        if (!Expand) {
2212          // We can't expand this pack expansion into separate arguments yet;
2213          // just substitute into the pattern and create a new pack expansion
2214          // type.
2215          Sema::ArgumentPackSubstitutionIndexRAII SubstIndex(SemaRef, -1);
2216          QualType T = SemaRef.SubstType(PackExpansion->getPattern(),
2217                                         TemplateArgs,
2218                                       New->getLocation(), New->getDeclName());
2219          if (T.isNull())
2220            break;
2221
2222          T = SemaRef.Context.getPackExpansionType(T, NumExpansions);
2223          Exceptions.push_back(T);
2224          continue;
2225        }
2226
2227        // Substitute into the pack expansion pattern for each template
2228        bool Invalid = false;
2229        for (unsigned ArgIdx = 0; ArgIdx != *NumExpansions; ++ArgIdx) {
2230          Sema::ArgumentPackSubstitutionIndexRAII SubstIndex(SemaRef, ArgIdx);
2231
2232          QualType T = SemaRef.SubstType(PackExpansion->getPattern(),
2233                                         TemplateArgs,
2234                                       New->getLocation(), New->getDeclName());
2235          if (T.isNull()) {
2236            Invalid = true;
2237            break;
2238          }
2239
2240          Exceptions.push_back(T);
2241        }
2242
2243        if (Invalid)
2244          break;
2245
2246        continue;
2247      }
2248
2249      QualType T
2250        = SemaRef.SubstType(Proto->getExceptionType(I), TemplateArgs,
2251                            New->getLocation(), New->getDeclName());
2252      if (T.isNull() ||
2253          SemaRef.CheckSpecifiedExceptionType(T, New->getLocation()))
2254        continue;
2255
2256      Exceptions.push_back(T);
2257    }
2258    Expr *NoexceptExpr = 0;
2259    if (Expr *OldNoexceptExpr = Proto->getNoexceptExpr()) {
2260      EnterExpressionEvaluationContext Unevaluated(SemaRef, Sema::Unevaluated);
2261      ExprResult E = SemaRef.SubstExpr(OldNoexceptExpr, TemplateArgs);
2262      if (E.isUsable())
2263        NoexceptExpr = E.take();
2264    }
2265
2266    // Rebuild the function type
2267
2268    FunctionProtoType::ExtProtoInfo EPI = Proto->getExtProtoInfo();
2269    EPI.ExceptionSpecType = Proto->getExceptionSpecType();
2270    EPI.NumExceptions = Exceptions.size();
2271    EPI.Exceptions = Exceptions.data();
2272    EPI.NoexceptExpr = NoexceptExpr;
2273    EPI.ExtInfo = Proto->getExtInfo();
2274
2275    const FunctionProtoType *NewProto
2276      = New->getType()->getAs<FunctionProtoType>();
2277    assert(NewProto && "Template instantiation without function prototype?");
2278    New->setType(SemaRef.Context.getFunctionType(NewProto->getResultType(),
2279                                                 NewProto->arg_type_begin(),
2280                                                 NewProto->getNumArgs(),
2281                                                 EPI));
2282  }
2283
2284  const FunctionDecl* Definition = Tmpl;
2285
2286  // Get the definition. Leaves the variable unchanged if undefined.
2287  Tmpl->isDefined(Definition);
2288
2289  SemaRef.InstantiateAttrs(TemplateArgs, Definition, New);
2290
2291  return false;
2292}
2293
2294/// \brief Initializes common fields of an instantiated method
2295/// declaration (New) from the corresponding fields of its template
2296/// (Tmpl).
2297///
2298/// \returns true if there was an error
2299bool
2300TemplateDeclInstantiator::InitMethodInstantiation(CXXMethodDecl *New,
2301                                                  CXXMethodDecl *Tmpl) {
2302  if (InitFunctionInstantiation(New, Tmpl))
2303    return true;
2304
2305  New->setAccess(Tmpl->getAccess());
2306  if (Tmpl->isVirtualAsWritten())
2307    New->setVirtualAsWritten(true);
2308
2309  // FIXME: attributes
2310  // FIXME: New needs a pointer to Tmpl
2311  return false;
2312}
2313
2314/// \brief Instantiate the definition of the given function from its
2315/// template.
2316///
2317/// \param PointOfInstantiation the point at which the instantiation was
2318/// required. Note that this is not precisely a "point of instantiation"
2319/// for the function, but it's close.
2320///
2321/// \param Function the already-instantiated declaration of a
2322/// function template specialization or member function of a class template
2323/// specialization.
2324///
2325/// \param Recursive if true, recursively instantiates any functions that
2326/// are required by this instantiation.
2327///
2328/// \param DefinitionRequired if true, then we are performing an explicit
2329/// instantiation where the body of the function is required. Complain if
2330/// there is no such body.
2331void Sema::InstantiateFunctionDefinition(SourceLocation PointOfInstantiation,
2332                                         FunctionDecl *Function,
2333                                         bool Recursive,
2334                                         bool DefinitionRequired) {
2335  if (Function->isInvalidDecl() || Function->isDefined())
2336    return;
2337
2338  // Never instantiate an explicit specialization.
2339  if (Function->getTemplateSpecializationKind() == TSK_ExplicitSpecialization)
2340    return;
2341
2342  // Find the function body that we'll be substituting.
2343  const FunctionDecl *PatternDecl = Function->getTemplateInstantiationPattern();
2344  assert(PatternDecl && "instantiating a non-template");
2345
2346  Stmt *Pattern = PatternDecl->getBody(PatternDecl);
2347  assert(PatternDecl && "template definition is not a template");
2348  if (!Pattern) {
2349    // Try to find a defaulted definition
2350    PatternDecl->isDefined(PatternDecl);
2351  }
2352  assert(PatternDecl && "template definition is not a template");
2353
2354  // Postpone late parsed template instantiations.
2355  if (PatternDecl->isLateTemplateParsed() &&
2356      !LateTemplateParser) {
2357    PendingInstantiations.push_back(
2358      std::make_pair(Function, PointOfInstantiation));
2359    return;
2360  }
2361
2362  // Call the LateTemplateParser callback if there a need to late parse
2363  // a templated function definition.
2364  if (!Pattern && PatternDecl->isLateTemplateParsed() &&
2365      LateTemplateParser) {
2366    LateTemplateParser(OpaqueParser, PatternDecl);
2367    Pattern = PatternDecl->getBody(PatternDecl);
2368  }
2369
2370  if (!Pattern && !PatternDecl->isDefaulted()) {
2371    if (DefinitionRequired) {
2372      if (Function->getPrimaryTemplate())
2373        Diag(PointOfInstantiation,
2374             diag::err_explicit_instantiation_undefined_func_template)
2375          << Function->getPrimaryTemplate();
2376      else
2377        Diag(PointOfInstantiation,
2378             diag::err_explicit_instantiation_undefined_member)
2379          << 1 << Function->getDeclName() << Function->getDeclContext();
2380
2381      if (PatternDecl)
2382        Diag(PatternDecl->getLocation(),
2383             diag::note_explicit_instantiation_here);
2384      Function->setInvalidDecl();
2385    } else if (Function->getTemplateSpecializationKind()
2386                 == TSK_ExplicitInstantiationDefinition) {
2387      PendingInstantiations.push_back(
2388        std::make_pair(Function, PointOfInstantiation));
2389    }
2390
2391    return;
2392  }
2393
2394  // C++0x [temp.explicit]p9:
2395  //   Except for inline functions, other explicit instantiation declarations
2396  //   have the effect of suppressing the implicit instantiation of the entity
2397  //   to which they refer.
2398  if (Function->getTemplateSpecializationKind()
2399        == TSK_ExplicitInstantiationDeclaration &&
2400      !PatternDecl->isInlined())
2401    return;
2402
2403  InstantiatingTemplate Inst(*this, PointOfInstantiation, Function);
2404  if (Inst)
2405    return;
2406
2407  // If we're performing recursive template instantiation, create our own
2408  // queue of pending implicit instantiations that we will instantiate later,
2409  // while we're still within our own instantiation context.
2410  SmallVector<VTableUse, 16> SavedVTableUses;
2411  std::deque<PendingImplicitInstantiation> SavedPendingInstantiations;
2412  if (Recursive) {
2413    VTableUses.swap(SavedVTableUses);
2414    PendingInstantiations.swap(SavedPendingInstantiations);
2415  }
2416
2417  EnterExpressionEvaluationContext EvalContext(*this,
2418                                               Sema::PotentiallyEvaluated);
2419  ActOnStartOfFunctionDef(0, Function);
2420
2421  // Introduce a new scope where local variable instantiations will be
2422  // recorded, unless we're actually a member function within a local
2423  // class, in which case we need to merge our results with the parent
2424  // scope (of the enclosing function).
2425  bool MergeWithParentScope = false;
2426  if (CXXRecordDecl *Rec = dyn_cast<CXXRecordDecl>(Function->getDeclContext()))
2427    MergeWithParentScope = Rec->isLocalClass();
2428
2429  LocalInstantiationScope Scope(*this, MergeWithParentScope);
2430
2431  // Introduce the instantiated function parameters into the local
2432  // instantiation scope, and set the parameter names to those used
2433  // in the template.
2434  unsigned FParamIdx = 0;
2435  for (unsigned I = 0, N = PatternDecl->getNumParams(); I != N; ++I) {
2436    const ParmVarDecl *PatternParam = PatternDecl->getParamDecl(I);
2437    if (!PatternParam->isParameterPack()) {
2438      // Simple case: not a parameter pack.
2439      assert(FParamIdx < Function->getNumParams());
2440      ParmVarDecl *FunctionParam = Function->getParamDecl(I);
2441      FunctionParam->setDeclName(PatternParam->getDeclName());
2442      Scope.InstantiatedLocal(PatternParam, FunctionParam);
2443      ++FParamIdx;
2444      continue;
2445    }
2446
2447    // Expand the parameter pack.
2448    Scope.MakeInstantiatedLocalArgPack(PatternParam);
2449    for (unsigned NumFParams = Function->getNumParams();
2450         FParamIdx < NumFParams;
2451         ++FParamIdx) {
2452      ParmVarDecl *FunctionParam = Function->getParamDecl(FParamIdx);
2453      FunctionParam->setDeclName(PatternParam->getDeclName());
2454      Scope.InstantiatedLocalPackArg(PatternParam, FunctionParam);
2455    }
2456  }
2457
2458  // Enter the scope of this instantiation. We don't use
2459  // PushDeclContext because we don't have a scope.
2460  Sema::ContextRAII savedContext(*this, Function);
2461
2462  MultiLevelTemplateArgumentList TemplateArgs =
2463    getTemplateInstantiationArgs(Function, 0, false, PatternDecl);
2464
2465  if (PatternDecl->isDefaulted()) {
2466    ActOnFinishFunctionBody(Function, 0, /*IsInstantiation=*/true);
2467
2468    SetDeclDefaulted(Function, PatternDecl->getLocation());
2469  } else {
2470    // If this is a constructor, instantiate the member initializers.
2471    if (const CXXConstructorDecl *Ctor =
2472          dyn_cast<CXXConstructorDecl>(PatternDecl)) {
2473      InstantiateMemInitializers(cast<CXXConstructorDecl>(Function), Ctor,
2474                                 TemplateArgs);
2475    }
2476
2477    // Instantiate the function body.
2478    StmtResult Body = SubstStmt(Pattern, TemplateArgs);
2479
2480    if (Body.isInvalid())
2481      Function->setInvalidDecl();
2482
2483    ActOnFinishFunctionBody(Function, Body.get(),
2484                            /*IsInstantiation=*/true);
2485  }
2486
2487  PerformDependentDiagnostics(PatternDecl, TemplateArgs);
2488
2489  savedContext.pop();
2490
2491  DeclGroupRef DG(Function);
2492  Consumer.HandleTopLevelDecl(DG);
2493
2494  // This class may have local implicit instantiations that need to be
2495  // instantiation within this scope.
2496  PerformPendingInstantiations(/*LocalOnly=*/true);
2497  Scope.Exit();
2498
2499  if (Recursive) {
2500    // Define any pending vtables.
2501    DefineUsedVTables();
2502
2503    // Instantiate any pending implicit instantiations found during the
2504    // instantiation of this template.
2505    PerformPendingInstantiations();
2506
2507    // Restore the set of pending vtables.
2508    assert(VTableUses.empty() &&
2509           "VTableUses should be empty before it is discarded.");
2510    VTableUses.swap(SavedVTableUses);
2511
2512    // Restore the set of pending implicit instantiations.
2513    assert(PendingInstantiations.empty() &&
2514           "PendingInstantiations should be empty before it is discarded.");
2515    PendingInstantiations.swap(SavedPendingInstantiations);
2516  }
2517}
2518
2519/// \brief Instantiate the definition of the given variable from its
2520/// template.
2521///
2522/// \param PointOfInstantiation the point at which the instantiation was
2523/// required. Note that this is not precisely a "point of instantiation"
2524/// for the function, but it's close.
2525///
2526/// \param Var the already-instantiated declaration of a static member
2527/// variable of a class template specialization.
2528///
2529/// \param Recursive if true, recursively instantiates any functions that
2530/// are required by this instantiation.
2531///
2532/// \param DefinitionRequired if true, then we are performing an explicit
2533/// instantiation where an out-of-line definition of the member variable
2534/// is required. Complain if there is no such definition.
2535void Sema::InstantiateStaticDataMemberDefinition(
2536                                          SourceLocation PointOfInstantiation,
2537                                                 VarDecl *Var,
2538                                                 bool Recursive,
2539                                                 bool DefinitionRequired) {
2540  if (Var->isInvalidDecl())
2541    return;
2542
2543  // Find the out-of-line definition of this static data member.
2544  VarDecl *Def = Var->getInstantiatedFromStaticDataMember();
2545  assert(Def && "This data member was not instantiated from a template?");
2546  assert(Def->isStaticDataMember() && "Not a static data member?");
2547  Def = Def->getOutOfLineDefinition();
2548
2549  if (!Def) {
2550    // We did not find an out-of-line definition of this static data member,
2551    // so we won't perform any instantiation. Rather, we rely on the user to
2552    // instantiate this definition (or provide a specialization for it) in
2553    // another translation unit.
2554    if (DefinitionRequired) {
2555      Def = Var->getInstantiatedFromStaticDataMember();
2556      Diag(PointOfInstantiation,
2557           diag::err_explicit_instantiation_undefined_member)
2558        << 2 << Var->getDeclName() << Var->getDeclContext();
2559      Diag(Def->getLocation(), diag::note_explicit_instantiation_here);
2560    } else if (Var->getTemplateSpecializationKind()
2561                 == TSK_ExplicitInstantiationDefinition) {
2562      PendingInstantiations.push_back(
2563        std::make_pair(Var, PointOfInstantiation));
2564    }
2565
2566    return;
2567  }
2568
2569  // Never instantiate an explicit specialization.
2570  if (Var->getTemplateSpecializationKind() == TSK_ExplicitSpecialization)
2571    return;
2572
2573  // C++0x [temp.explicit]p9:
2574  //   Except for inline functions, other explicit instantiation declarations
2575  //   have the effect of suppressing the implicit instantiation of the entity
2576  //   to which they refer.
2577  if (Var->getTemplateSpecializationKind()
2578        == TSK_ExplicitInstantiationDeclaration)
2579    return;
2580
2581  // If we already have a definition, we're done.
2582  if (Var->getDefinition())
2583    return;
2584
2585  InstantiatingTemplate Inst(*this, PointOfInstantiation, Var);
2586  if (Inst)
2587    return;
2588
2589  // If we're performing recursive template instantiation, create our own
2590  // queue of pending implicit instantiations that we will instantiate later,
2591  // while we're still within our own instantiation context.
2592  SmallVector<VTableUse, 16> SavedVTableUses;
2593  std::deque<PendingImplicitInstantiation> SavedPendingInstantiations;
2594  if (Recursive) {
2595    VTableUses.swap(SavedVTableUses);
2596    PendingInstantiations.swap(SavedPendingInstantiations);
2597  }
2598
2599  // Enter the scope of this instantiation. We don't use
2600  // PushDeclContext because we don't have a scope.
2601  ContextRAII previousContext(*this, Var->getDeclContext());
2602
2603  VarDecl *OldVar = Var;
2604  Var = cast_or_null<VarDecl>(SubstDecl(Def, Var->getDeclContext(),
2605                                        getTemplateInstantiationArgs(Var)));
2606
2607  previousContext.pop();
2608
2609  if (Var) {
2610    MemberSpecializationInfo *MSInfo = OldVar->getMemberSpecializationInfo();
2611    assert(MSInfo && "Missing member specialization information?");
2612    Var->setTemplateSpecializationKind(MSInfo->getTemplateSpecializationKind(),
2613                                       MSInfo->getPointOfInstantiation());
2614    DeclGroupRef DG(Var);
2615    Consumer.HandleTopLevelDecl(DG);
2616  }
2617
2618  if (Recursive) {
2619    // Define any newly required vtables.
2620    DefineUsedVTables();
2621
2622    // Instantiate any pending implicit instantiations found during the
2623    // instantiation of this template.
2624    PerformPendingInstantiations();
2625
2626    // Restore the set of pending vtables.
2627    assert(VTableUses.empty() &&
2628           "VTableUses should be empty before it is discarded, "
2629           "while instantiating static data member.");
2630    VTableUses.swap(SavedVTableUses);
2631
2632    // Restore the set of pending implicit instantiations.
2633    assert(PendingInstantiations.empty() &&
2634           "PendingInstantiations should be empty before it is discarded, "
2635           "while instantiating static data member.");
2636    PendingInstantiations.swap(SavedPendingInstantiations);
2637  }
2638}
2639
2640void
2641Sema::InstantiateMemInitializers(CXXConstructorDecl *New,
2642                                 const CXXConstructorDecl *Tmpl,
2643                           const MultiLevelTemplateArgumentList &TemplateArgs) {
2644
2645  SmallVector<MemInitTy*, 4> NewInits;
2646  bool AnyErrors = false;
2647
2648  // Instantiate all the initializers.
2649  for (CXXConstructorDecl::init_const_iterator Inits = Tmpl->init_begin(),
2650                                            InitsEnd = Tmpl->init_end();
2651       Inits != InitsEnd; ++Inits) {
2652    CXXCtorInitializer *Init = *Inits;
2653
2654    // Only instantiate written initializers, let Sema re-construct implicit
2655    // ones.
2656    if (!Init->isWritten())
2657      continue;
2658
2659    SourceLocation LParenLoc, RParenLoc;
2660    ASTOwningVector<Expr*> NewArgs(*this);
2661
2662    SourceLocation EllipsisLoc;
2663
2664    if (Init->isPackExpansion()) {
2665      // This is a pack expansion. We should expand it now.
2666      TypeLoc BaseTL = Init->getBaseClassInfo()->getTypeLoc();
2667      SmallVector<UnexpandedParameterPack, 2> Unexpanded;
2668      collectUnexpandedParameterPacks(BaseTL, Unexpanded);
2669      bool ShouldExpand = false;
2670      bool RetainExpansion = false;
2671      llvm::Optional<unsigned> NumExpansions;
2672      if (CheckParameterPacksForExpansion(Init->getEllipsisLoc(),
2673                                          BaseTL.getSourceRange(),
2674                                          Unexpanded.data(),
2675                                          Unexpanded.size(),
2676                                          TemplateArgs, ShouldExpand,
2677                                          RetainExpansion,
2678                                          NumExpansions)) {
2679        AnyErrors = true;
2680        New->setInvalidDecl();
2681        continue;
2682      }
2683      assert(ShouldExpand && "Partial instantiation of base initializer?");
2684
2685      // Loop over all of the arguments in the argument pack(s),
2686      for (unsigned I = 0; I != *NumExpansions; ++I) {
2687        Sema::ArgumentPackSubstitutionIndexRAII SubstIndex(*this, I);
2688
2689        // Instantiate the initializer.
2690        if (InstantiateInitializer(Init->getInit(), TemplateArgs,
2691                                   LParenLoc, NewArgs, RParenLoc)) {
2692          AnyErrors = true;
2693          break;
2694        }
2695
2696        // Instantiate the base type.
2697        TypeSourceInfo *BaseTInfo = SubstType(Init->getBaseClassInfo(),
2698                                              TemplateArgs,
2699                                              Init->getSourceLocation(),
2700                                              New->getDeclName());
2701        if (!BaseTInfo) {
2702          AnyErrors = true;
2703          break;
2704        }
2705
2706        // Build the initializer.
2707        MemInitResult NewInit = BuildBaseInitializer(BaseTInfo->getType(),
2708                                                     BaseTInfo,
2709                                                     (Expr **)NewArgs.data(),
2710                                                     NewArgs.size(),
2711                                                     Init->getLParenLoc(),
2712                                                     Init->getRParenLoc(),
2713                                                     New->getParent(),
2714                                                     SourceLocation());
2715        if (NewInit.isInvalid()) {
2716          AnyErrors = true;
2717          break;
2718        }
2719
2720        NewInits.push_back(NewInit.get());
2721        NewArgs.clear();
2722      }
2723
2724      continue;
2725    }
2726
2727    // Instantiate the initializer.
2728    if (InstantiateInitializer(Init->getInit(), TemplateArgs,
2729                               LParenLoc, NewArgs, RParenLoc)) {
2730      AnyErrors = true;
2731      continue;
2732    }
2733
2734    MemInitResult NewInit;
2735    if (Init->isBaseInitializer()) {
2736      TypeSourceInfo *BaseTInfo = SubstType(Init->getBaseClassInfo(),
2737                                            TemplateArgs,
2738                                            Init->getSourceLocation(),
2739                                            New->getDeclName());
2740      if (!BaseTInfo) {
2741        AnyErrors = true;
2742        New->setInvalidDecl();
2743        continue;
2744      }
2745
2746      NewInit = BuildBaseInitializer(BaseTInfo->getType(), BaseTInfo,
2747                                     (Expr **)NewArgs.data(),
2748                                     NewArgs.size(),
2749                                     Init->getLParenLoc(),
2750                                     Init->getRParenLoc(),
2751                                     New->getParent(),
2752                                     EllipsisLoc);
2753    } else if (Init->isMemberInitializer()) {
2754      FieldDecl *Member = cast_or_null<FieldDecl>(FindInstantiatedDecl(
2755                                                     Init->getMemberLocation(),
2756                                                     Init->getMember(),
2757                                                     TemplateArgs));
2758      if (!Member) {
2759        AnyErrors = true;
2760        New->setInvalidDecl();
2761        continue;
2762      }
2763
2764      NewInit = BuildMemberInitializer(Member, (Expr **)NewArgs.data(),
2765                                       NewArgs.size(),
2766                                       Init->getSourceLocation(),
2767                                       Init->getLParenLoc(),
2768                                       Init->getRParenLoc());
2769    } else if (Init->isIndirectMemberInitializer()) {
2770      IndirectFieldDecl *IndirectMember =
2771         cast_or_null<IndirectFieldDecl>(FindInstantiatedDecl(
2772                                 Init->getMemberLocation(),
2773                                 Init->getIndirectMember(), TemplateArgs));
2774
2775      if (!IndirectMember) {
2776        AnyErrors = true;
2777        New->setInvalidDecl();
2778        continue;
2779      }
2780
2781      NewInit = BuildMemberInitializer(IndirectMember, (Expr **)NewArgs.data(),
2782                                       NewArgs.size(),
2783                                       Init->getSourceLocation(),
2784                                       Init->getLParenLoc(),
2785                                       Init->getRParenLoc());
2786    }
2787
2788    if (NewInit.isInvalid()) {
2789      AnyErrors = true;
2790      New->setInvalidDecl();
2791    } else {
2792      // FIXME: It would be nice if ASTOwningVector had a release function.
2793      NewArgs.take();
2794
2795      NewInits.push_back((MemInitTy *)NewInit.get());
2796    }
2797  }
2798
2799  // Assign all the initializers to the new constructor.
2800  ActOnMemInitializers(New,
2801                       /*FIXME: ColonLoc */
2802                       SourceLocation(),
2803                       NewInits.data(), NewInits.size(),
2804                       AnyErrors);
2805}
2806
2807// TODO: this could be templated if the various decl types used the
2808// same method name.
2809static bool isInstantiationOf(ClassTemplateDecl *Pattern,
2810                              ClassTemplateDecl *Instance) {
2811  Pattern = Pattern->getCanonicalDecl();
2812
2813  do {
2814    Instance = Instance->getCanonicalDecl();
2815    if (Pattern == Instance) return true;
2816    Instance = Instance->getInstantiatedFromMemberTemplate();
2817  } while (Instance);
2818
2819  return false;
2820}
2821
2822static bool isInstantiationOf(FunctionTemplateDecl *Pattern,
2823                              FunctionTemplateDecl *Instance) {
2824  Pattern = Pattern->getCanonicalDecl();
2825
2826  do {
2827    Instance = Instance->getCanonicalDecl();
2828    if (Pattern == Instance) return true;
2829    Instance = Instance->getInstantiatedFromMemberTemplate();
2830  } while (Instance);
2831
2832  return false;
2833}
2834
2835static bool
2836isInstantiationOf(ClassTemplatePartialSpecializationDecl *Pattern,
2837                  ClassTemplatePartialSpecializationDecl *Instance) {
2838  Pattern
2839    = cast<ClassTemplatePartialSpecializationDecl>(Pattern->getCanonicalDecl());
2840  do {
2841    Instance = cast<ClassTemplatePartialSpecializationDecl>(
2842                                                Instance->getCanonicalDecl());
2843    if (Pattern == Instance)
2844      return true;
2845    Instance = Instance->getInstantiatedFromMember();
2846  } while (Instance);
2847
2848  return false;
2849}
2850
2851static bool isInstantiationOf(CXXRecordDecl *Pattern,
2852                              CXXRecordDecl *Instance) {
2853  Pattern = Pattern->getCanonicalDecl();
2854
2855  do {
2856    Instance = Instance->getCanonicalDecl();
2857    if (Pattern == Instance) return true;
2858    Instance = Instance->getInstantiatedFromMemberClass();
2859  } while (Instance);
2860
2861  return false;
2862}
2863
2864static bool isInstantiationOf(FunctionDecl *Pattern,
2865                              FunctionDecl *Instance) {
2866  Pattern = Pattern->getCanonicalDecl();
2867
2868  do {
2869    Instance = Instance->getCanonicalDecl();
2870    if (Pattern == Instance) return true;
2871    Instance = Instance->getInstantiatedFromMemberFunction();
2872  } while (Instance);
2873
2874  return false;
2875}
2876
2877static bool isInstantiationOf(EnumDecl *Pattern,
2878                              EnumDecl *Instance) {
2879  Pattern = Pattern->getCanonicalDecl();
2880
2881  do {
2882    Instance = Instance->getCanonicalDecl();
2883    if (Pattern == Instance) return true;
2884    Instance = Instance->getInstantiatedFromMemberEnum();
2885  } while (Instance);
2886
2887  return false;
2888}
2889
2890static bool isInstantiationOf(UsingShadowDecl *Pattern,
2891                              UsingShadowDecl *Instance,
2892                              ASTContext &C) {
2893  return C.getInstantiatedFromUsingShadowDecl(Instance) == Pattern;
2894}
2895
2896static bool isInstantiationOf(UsingDecl *Pattern,
2897                              UsingDecl *Instance,
2898                              ASTContext &C) {
2899  return C.getInstantiatedFromUsingDecl(Instance) == Pattern;
2900}
2901
2902static bool isInstantiationOf(UnresolvedUsingValueDecl *Pattern,
2903                              UsingDecl *Instance,
2904                              ASTContext &C) {
2905  return C.getInstantiatedFromUsingDecl(Instance) == Pattern;
2906}
2907
2908static bool isInstantiationOf(UnresolvedUsingTypenameDecl *Pattern,
2909                              UsingDecl *Instance,
2910                              ASTContext &C) {
2911  return C.getInstantiatedFromUsingDecl(Instance) == Pattern;
2912}
2913
2914static bool isInstantiationOfStaticDataMember(VarDecl *Pattern,
2915                                              VarDecl *Instance) {
2916  assert(Instance->isStaticDataMember());
2917
2918  Pattern = Pattern->getCanonicalDecl();
2919
2920  do {
2921    Instance = Instance->getCanonicalDecl();
2922    if (Pattern == Instance) return true;
2923    Instance = Instance->getInstantiatedFromStaticDataMember();
2924  } while (Instance);
2925
2926  return false;
2927}
2928
2929// Other is the prospective instantiation
2930// D is the prospective pattern
2931static bool isInstantiationOf(ASTContext &Ctx, NamedDecl *D, Decl *Other) {
2932  if (D->getKind() != Other->getKind()) {
2933    if (UnresolvedUsingTypenameDecl *UUD
2934          = dyn_cast<UnresolvedUsingTypenameDecl>(D)) {
2935      if (UsingDecl *UD = dyn_cast<UsingDecl>(Other)) {
2936        return isInstantiationOf(UUD, UD, Ctx);
2937      }
2938    }
2939
2940    if (UnresolvedUsingValueDecl *UUD
2941          = dyn_cast<UnresolvedUsingValueDecl>(D)) {
2942      if (UsingDecl *UD = dyn_cast<UsingDecl>(Other)) {
2943        return isInstantiationOf(UUD, UD, Ctx);
2944      }
2945    }
2946
2947    return false;
2948  }
2949
2950  if (CXXRecordDecl *Record = dyn_cast<CXXRecordDecl>(Other))
2951    return isInstantiationOf(cast<CXXRecordDecl>(D), Record);
2952
2953  if (FunctionDecl *Function = dyn_cast<FunctionDecl>(Other))
2954    return isInstantiationOf(cast<FunctionDecl>(D), Function);
2955
2956  if (EnumDecl *Enum = dyn_cast<EnumDecl>(Other))
2957    return isInstantiationOf(cast<EnumDecl>(D), Enum);
2958
2959  if (VarDecl *Var = dyn_cast<VarDecl>(Other))
2960    if (Var->isStaticDataMember())
2961      return isInstantiationOfStaticDataMember(cast<VarDecl>(D), Var);
2962
2963  if (ClassTemplateDecl *Temp = dyn_cast<ClassTemplateDecl>(Other))
2964    return isInstantiationOf(cast<ClassTemplateDecl>(D), Temp);
2965
2966  if (FunctionTemplateDecl *Temp = dyn_cast<FunctionTemplateDecl>(Other))
2967    return isInstantiationOf(cast<FunctionTemplateDecl>(D), Temp);
2968
2969  if (ClassTemplatePartialSpecializationDecl *PartialSpec
2970        = dyn_cast<ClassTemplatePartialSpecializationDecl>(Other))
2971    return isInstantiationOf(cast<ClassTemplatePartialSpecializationDecl>(D),
2972                             PartialSpec);
2973
2974  if (FieldDecl *Field = dyn_cast<FieldDecl>(Other)) {
2975    if (!Field->getDeclName()) {
2976      // This is an unnamed field.
2977      return Ctx.getInstantiatedFromUnnamedFieldDecl(Field) ==
2978        cast<FieldDecl>(D);
2979    }
2980  }
2981
2982  if (UsingDecl *Using = dyn_cast<UsingDecl>(Other))
2983    return isInstantiationOf(cast<UsingDecl>(D), Using, Ctx);
2984
2985  if (UsingShadowDecl *Shadow = dyn_cast<UsingShadowDecl>(Other))
2986    return isInstantiationOf(cast<UsingShadowDecl>(D), Shadow, Ctx);
2987
2988  return D->getDeclName() && isa<NamedDecl>(Other) &&
2989    D->getDeclName() == cast<NamedDecl>(Other)->getDeclName();
2990}
2991
2992template<typename ForwardIterator>
2993static NamedDecl *findInstantiationOf(ASTContext &Ctx,
2994                                      NamedDecl *D,
2995                                      ForwardIterator first,
2996                                      ForwardIterator last) {
2997  for (; first != last; ++first)
2998    if (isInstantiationOf(Ctx, D, *first))
2999      return cast<NamedDecl>(*first);
3000
3001  return 0;
3002}
3003
3004/// \brief Finds the instantiation of the given declaration context
3005/// within the current instantiation.
3006///
3007/// \returns NULL if there was an error
3008DeclContext *Sema::FindInstantiatedContext(SourceLocation Loc, DeclContext* DC,
3009                          const MultiLevelTemplateArgumentList &TemplateArgs) {
3010  if (NamedDecl *D = dyn_cast<NamedDecl>(DC)) {
3011    Decl* ID = FindInstantiatedDecl(Loc, D, TemplateArgs);
3012    return cast_or_null<DeclContext>(ID);
3013  } else return DC;
3014}
3015
3016/// \brief Find the instantiation of the given declaration within the
3017/// current instantiation.
3018///
3019/// This routine is intended to be used when \p D is a declaration
3020/// referenced from within a template, that needs to mapped into the
3021/// corresponding declaration within an instantiation. For example,
3022/// given:
3023///
3024/// \code
3025/// template<typename T>
3026/// struct X {
3027///   enum Kind {
3028///     KnownValue = sizeof(T)
3029///   };
3030///
3031///   bool getKind() const { return KnownValue; }
3032/// };
3033///
3034/// template struct X<int>;
3035/// \endcode
3036///
3037/// In the instantiation of X<int>::getKind(), we need to map the
3038/// EnumConstantDecl for KnownValue (which refers to
3039/// X<T>::<Kind>::KnownValue) to its instantiation
3040/// (X<int>::<Kind>::KnownValue). InstantiateCurrentDeclRef() performs
3041/// this mapping from within the instantiation of X<int>.
3042NamedDecl *Sema::FindInstantiatedDecl(SourceLocation Loc, NamedDecl *D,
3043                          const MultiLevelTemplateArgumentList &TemplateArgs) {
3044  DeclContext *ParentDC = D->getDeclContext();
3045  if (isa<ParmVarDecl>(D) || isa<NonTypeTemplateParmDecl>(D) ||
3046      isa<TemplateTypeParmDecl>(D) || isa<TemplateTemplateParmDecl>(D) ||
3047      (ParentDC->isFunctionOrMethod() && ParentDC->isDependentContext())) {
3048    // D is a local of some kind. Look into the map of local
3049    // declarations to their instantiations.
3050    typedef LocalInstantiationScope::DeclArgumentPack DeclArgumentPack;
3051    llvm::PointerUnion<Decl *, DeclArgumentPack *> *Found
3052      = CurrentInstantiationScope->findInstantiationOf(D);
3053
3054    if (Found) {
3055      if (Decl *FD = Found->dyn_cast<Decl *>())
3056        return cast<NamedDecl>(FD);
3057
3058      unsigned PackIdx = ArgumentPackSubstitutionIndex;
3059      return cast<NamedDecl>((*Found->get<DeclArgumentPack *>())[PackIdx]);
3060    }
3061
3062    // If we didn't find the decl, then we must have a label decl that hasn't
3063    // been found yet.  Lazily instantiate it and return it now.
3064    assert(isa<LabelDecl>(D));
3065
3066    Decl *Inst = SubstDecl(D, CurContext, TemplateArgs);
3067    assert(Inst && "Failed to instantiate label??");
3068
3069    CurrentInstantiationScope->InstantiatedLocal(D, Inst);
3070    return cast<LabelDecl>(Inst);
3071  }
3072
3073  if (CXXRecordDecl *Record = dyn_cast<CXXRecordDecl>(D)) {
3074    if (!Record->isDependentContext())
3075      return D;
3076
3077    // If the RecordDecl is actually the injected-class-name or a
3078    // "templated" declaration for a class template, class template
3079    // partial specialization, or a member class of a class template,
3080    // substitute into the injected-class-name of the class template
3081    // or partial specialization to find the new DeclContext.
3082    QualType T;
3083    ClassTemplateDecl *ClassTemplate = Record->getDescribedClassTemplate();
3084
3085    if (ClassTemplate) {
3086      T = ClassTemplate->getInjectedClassNameSpecialization();
3087    } else if (ClassTemplatePartialSpecializationDecl *PartialSpec
3088                 = dyn_cast<ClassTemplatePartialSpecializationDecl>(Record)) {
3089      ClassTemplate = PartialSpec->getSpecializedTemplate();
3090
3091      // If we call SubstType with an InjectedClassNameType here we
3092      // can end up in an infinite loop.
3093      T = Context.getTypeDeclType(Record);
3094      assert(isa<InjectedClassNameType>(T) &&
3095             "type of partial specialization is not an InjectedClassNameType");
3096      T = cast<InjectedClassNameType>(T)->getInjectedSpecializationType();
3097    }
3098
3099    if (!T.isNull()) {
3100      // Substitute into the injected-class-name to get the type
3101      // corresponding to the instantiation we want, which may also be
3102      // the current instantiation (if we're in a template
3103      // definition). This substitution should never fail, since we
3104      // know we can instantiate the injected-class-name or we
3105      // wouldn't have gotten to the injected-class-name!
3106
3107      // FIXME: Can we use the CurrentInstantiationScope to avoid this
3108      // extra instantiation in the common case?
3109      T = SubstType(T, TemplateArgs, Loc, DeclarationName());
3110      assert(!T.isNull() && "Instantiation of injected-class-name cannot fail.");
3111
3112      if (!T->isDependentType()) {
3113        assert(T->isRecordType() && "Instantiation must produce a record type");
3114        return T->getAs<RecordType>()->getDecl();
3115      }
3116
3117      // We are performing "partial" template instantiation to create
3118      // the member declarations for the members of a class template
3119      // specialization. Therefore, D is actually referring to something
3120      // in the current instantiation. Look through the current
3121      // context, which contains actual instantiations, to find the
3122      // instantiation of the "current instantiation" that D refers
3123      // to.
3124      bool SawNonDependentContext = false;
3125      for (DeclContext *DC = CurContext; !DC->isFileContext();
3126           DC = DC->getParent()) {
3127        if (ClassTemplateSpecializationDecl *Spec
3128                          = dyn_cast<ClassTemplateSpecializationDecl>(DC))
3129          if (isInstantiationOf(ClassTemplate,
3130                                Spec->getSpecializedTemplate()))
3131            return Spec;
3132
3133        if (!DC->isDependentContext())
3134          SawNonDependentContext = true;
3135      }
3136
3137      // We're performing "instantiation" of a member of the current
3138      // instantiation while we are type-checking the
3139      // definition. Compute the declaration context and return that.
3140      assert(!SawNonDependentContext &&
3141             "No dependent context while instantiating record");
3142      DeclContext *DC = computeDeclContext(T);
3143      assert(DC &&
3144             "Unable to find declaration for the current instantiation");
3145      return cast<CXXRecordDecl>(DC);
3146    }
3147
3148    // Fall through to deal with other dependent record types (e.g.,
3149    // anonymous unions in class templates).
3150  }
3151
3152  if (!ParentDC->isDependentContext())
3153    return D;
3154
3155  ParentDC = FindInstantiatedContext(Loc, ParentDC, TemplateArgs);
3156  if (!ParentDC)
3157    return 0;
3158
3159  if (ParentDC != D->getDeclContext()) {
3160    // We performed some kind of instantiation in the parent context,
3161    // so now we need to look into the instantiated parent context to
3162    // find the instantiation of the declaration D.
3163
3164    // If our context used to be dependent, we may need to instantiate
3165    // it before performing lookup into that context.
3166    bool IsBeingInstantiated = false;
3167    if (CXXRecordDecl *Spec = dyn_cast<CXXRecordDecl>(ParentDC)) {
3168      if (!Spec->isDependentContext()) {
3169        QualType T = Context.getTypeDeclType(Spec);
3170        const RecordType *Tag = T->getAs<RecordType>();
3171        assert(Tag && "type of non-dependent record is not a RecordType");
3172        if (Tag->isBeingDefined())
3173          IsBeingInstantiated = true;
3174        if (!Tag->isBeingDefined() &&
3175            RequireCompleteType(Loc, T, diag::err_incomplete_type))
3176          return 0;
3177
3178        ParentDC = Tag->getDecl();
3179      }
3180    }
3181
3182    NamedDecl *Result = 0;
3183    if (D->getDeclName()) {
3184      DeclContext::lookup_result Found = ParentDC->lookup(D->getDeclName());
3185      Result = findInstantiationOf(Context, D, Found.first, Found.second);
3186    } else {
3187      // Since we don't have a name for the entity we're looking for,
3188      // our only option is to walk through all of the declarations to
3189      // find that name. This will occur in a few cases:
3190      //
3191      //   - anonymous struct/union within a template
3192      //   - unnamed class/struct/union/enum within a template
3193      //
3194      // FIXME: Find a better way to find these instantiations!
3195      Result = findInstantiationOf(Context, D,
3196                                   ParentDC->decls_begin(),
3197                                   ParentDC->decls_end());
3198    }
3199
3200    if (!Result) {
3201      if (isa<UsingShadowDecl>(D)) {
3202        // UsingShadowDecls can instantiate to nothing because of using hiding.
3203      } else if (Diags.hasErrorOccurred()) {
3204        // We've already complained about something, so most likely this
3205        // declaration failed to instantiate. There's no point in complaining
3206        // further, since this is normal in invalid code.
3207      } else if (IsBeingInstantiated) {
3208        // The class in which this member exists is currently being
3209        // instantiated, and we haven't gotten around to instantiating this
3210        // member yet. This can happen when the code uses forward declarations
3211        // of member classes, and introduces ordering dependencies via
3212        // template instantiation.
3213        Diag(Loc, diag::err_member_not_yet_instantiated)
3214          << D->getDeclName()
3215          << Context.getTypeDeclType(cast<CXXRecordDecl>(ParentDC));
3216        Diag(D->getLocation(), diag::note_non_instantiated_member_here);
3217      } else {
3218        // We should have found something, but didn't.
3219        llvm_unreachable("Unable to find instantiation of declaration!");
3220      }
3221    }
3222
3223    D = Result;
3224  }
3225
3226  return D;
3227}
3228
3229/// \brief Performs template instantiation for all implicit template
3230/// instantiations we have seen until this point.
3231void Sema::PerformPendingInstantiations(bool LocalOnly) {
3232  // Load pending instantiations from the external source.
3233  if (!LocalOnly && ExternalSource) {
3234    SmallVector<std::pair<ValueDecl *, SourceLocation>, 4> Pending;
3235    ExternalSource->ReadPendingInstantiations(Pending);
3236    PendingInstantiations.insert(PendingInstantiations.begin(),
3237                                 Pending.begin(), Pending.end());
3238  }
3239
3240  while (!PendingLocalImplicitInstantiations.empty() ||
3241         (!LocalOnly && !PendingInstantiations.empty())) {
3242    PendingImplicitInstantiation Inst;
3243
3244    if (PendingLocalImplicitInstantiations.empty()) {
3245      Inst = PendingInstantiations.front();
3246      PendingInstantiations.pop_front();
3247    } else {
3248      Inst = PendingLocalImplicitInstantiations.front();
3249      PendingLocalImplicitInstantiations.pop_front();
3250    }
3251
3252    // Instantiate function definitions
3253    if (FunctionDecl *Function = dyn_cast<FunctionDecl>(Inst.first)) {
3254      PrettyDeclStackTraceEntry CrashInfo(*this, Function, SourceLocation(),
3255                                          "instantiating function definition");
3256      bool DefinitionRequired = Function->getTemplateSpecializationKind() ==
3257                                TSK_ExplicitInstantiationDefinition;
3258      InstantiateFunctionDefinition(/*FIXME:*/Inst.second, Function, true,
3259                                    DefinitionRequired);
3260      continue;
3261    }
3262
3263    // Instantiate static data member definitions.
3264    VarDecl *Var = cast<VarDecl>(Inst.first);
3265    assert(Var->isStaticDataMember() && "Not a static data member?");
3266
3267    // Don't try to instantiate declarations if the most recent redeclaration
3268    // is invalid.
3269    if (Var->getMostRecentDeclaration()->isInvalidDecl())
3270      continue;
3271
3272    // Check if the most recent declaration has changed the specialization kind
3273    // and removed the need for implicit instantiation.
3274    switch (Var->getMostRecentDeclaration()->getTemplateSpecializationKind()) {
3275    case TSK_Undeclared:
3276      assert(false && "Cannot instantitiate an undeclared specialization.");
3277    case TSK_ExplicitInstantiationDeclaration:
3278    case TSK_ExplicitSpecialization:
3279      continue;  // No longer need to instantiate this type.
3280    case TSK_ExplicitInstantiationDefinition:
3281      // We only need an instantiation if the pending instantiation *is* the
3282      // explicit instantiation.
3283      if (Var != Var->getMostRecentDeclaration()) continue;
3284    case TSK_ImplicitInstantiation:
3285      break;
3286    }
3287
3288    PrettyDeclStackTraceEntry CrashInfo(*this, Var, Var->getLocation(),
3289                                        "instantiating static data member "
3290                                        "definition");
3291
3292    bool DefinitionRequired = Var->getTemplateSpecializationKind() ==
3293                              TSK_ExplicitInstantiationDefinition;
3294    InstantiateStaticDataMemberDefinition(/*FIXME:*/Inst.second, Var, true,
3295                                          DefinitionRequired);
3296  }
3297}
3298
3299void Sema::PerformDependentDiagnostics(const DeclContext *Pattern,
3300                       const MultiLevelTemplateArgumentList &TemplateArgs) {
3301  for (DeclContext::ddiag_iterator I = Pattern->ddiag_begin(),
3302         E = Pattern->ddiag_end(); I != E; ++I) {
3303    DependentDiagnostic *DD = *I;
3304
3305    switch (DD->getKind()) {
3306    case DependentDiagnostic::Access:
3307      HandleDependentAccessCheck(*DD, TemplateArgs);
3308      break;
3309    }
3310  }
3311}
3312