SemaTemplateInstantiateDecl.cpp revision 162e1c1b487352434552147967c3dd296ebee2f7 
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                            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::VisitTypedefNameDecl(TypedefNameDecl *D,
132                                                     bool IsTypeAlias) {
133  bool Invalid = false;
134  TypeSourceInfo *DI = D->getTypeSourceInfo();
135  if (DI->getType()->isDependentType() ||
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  Owner->addDecl(Typedef);
182
183  return Typedef;
184}
185
186Decl *TemplateDeclInstantiator::VisitTypedefDecl(TypedefDecl *D) {
187  return VisitTypedefNameDecl(D, /*IsTypeAlias=*/false);
188}
189
190Decl *TemplateDeclInstantiator::VisitTypeAliasDecl(TypeAliasDecl *D) {
191  return VisitTypedefNameDecl(D, /*IsTypeAlias=*/true);
192}
193
194/// \brief Instantiate an initializer, breaking it into separate
195/// initialization arguments.
196///
197/// \param S The semantic analysis object.
198///
199/// \param Init The initializer to instantiate.
200///
201/// \param TemplateArgs Template arguments to be substituted into the
202/// initializer.
203///
204/// \param NewArgs Will be filled in with the instantiation arguments.
205///
206/// \returns true if an error occurred, false otherwise
207static bool InstantiateInitializer(Sema &S, Expr *Init,
208                            const MultiLevelTemplateArgumentList &TemplateArgs,
209                                   SourceLocation &LParenLoc,
210                                   ASTOwningVector<Expr*> &NewArgs,
211                                   SourceLocation &RParenLoc) {
212  NewArgs.clear();
213  LParenLoc = SourceLocation();
214  RParenLoc = SourceLocation();
215
216  if (!Init)
217    return false;
218
219  if (ExprWithCleanups *ExprTemp = dyn_cast<ExprWithCleanups>(Init))
220    Init = ExprTemp->getSubExpr();
221
222  while (CXXBindTemporaryExpr *Binder = dyn_cast<CXXBindTemporaryExpr>(Init))
223    Init = Binder->getSubExpr();
224
225  if (ImplicitCastExpr *ICE = dyn_cast<ImplicitCastExpr>(Init))
226    Init = ICE->getSubExprAsWritten();
227
228  if (ParenListExpr *ParenList = dyn_cast<ParenListExpr>(Init)) {
229    LParenLoc = ParenList->getLParenLoc();
230    RParenLoc = ParenList->getRParenLoc();
231    return S.SubstExprs(ParenList->getExprs(), ParenList->getNumExprs(),
232                        true, TemplateArgs, NewArgs);
233  }
234
235  if (CXXConstructExpr *Construct = dyn_cast<CXXConstructExpr>(Init)) {
236    if (!isa<CXXTemporaryObjectExpr>(Construct)) {
237      if (S.SubstExprs(Construct->getArgs(), Construct->getNumArgs(), true,
238                       TemplateArgs, NewArgs))
239        return true;
240
241      // FIXME: Fake locations!
242      LParenLoc = S.PP.getLocForEndOfToken(Init->getLocStart());
243      RParenLoc = LParenLoc;
244      return false;
245    }
246  }
247
248  ExprResult Result = S.SubstExpr(Init, TemplateArgs);
249  if (Result.isInvalid())
250    return true;
251
252  NewArgs.push_back(Result.takeAs<Expr>());
253  return false;
254}
255
256Decl *TemplateDeclInstantiator::VisitVarDecl(VarDecl *D) {
257  // If this is the variable for an anonymous struct or union,
258  // instantiate the anonymous struct/union type first.
259  if (const RecordType *RecordTy = D->getType()->getAs<RecordType>())
260    if (RecordTy->getDecl()->isAnonymousStructOrUnion())
261      if (!VisitCXXRecordDecl(cast<CXXRecordDecl>(RecordTy->getDecl())))
262        return 0;
263
264  // Do substitution on the type of the declaration
265  TypeSourceInfo *DI = SemaRef.SubstType(D->getTypeSourceInfo(),
266                                         TemplateArgs,
267                                         D->getTypeSpecStartLoc(),
268                                         D->getDeclName());
269  if (!DI)
270    return 0;
271
272  if (DI->getType()->isFunctionType()) {
273    SemaRef.Diag(D->getLocation(), diag::err_variable_instantiates_to_function)
274      << D->isStaticDataMember() << DI->getType();
275    return 0;
276  }
277
278  // Build the instantiated declaration
279  VarDecl *Var = VarDecl::Create(SemaRef.Context, Owner,
280                                 D->getInnerLocStart(),
281                                 D->getLocation(), D->getIdentifier(),
282                                 DI->getType(), DI,
283                                 D->getStorageClass(),
284                                 D->getStorageClassAsWritten());
285  Var->setThreadSpecified(D->isThreadSpecified());
286  Var->setCXXDirectInitializer(D->hasCXXDirectInitializer());
287  Var->setCXXForRangeDecl(D->isCXXForRangeDecl());
288
289  // Substitute the nested name specifier, if any.
290  if (SubstQualifier(D, Var))
291    return 0;
292
293  // If we are instantiating a static data member defined
294  // out-of-line, the instantiation will have the same lexical
295  // context (which will be a namespace scope) as the template.
296  if (D->isOutOfLine())
297    Var->setLexicalDeclContext(D->getLexicalDeclContext());
298
299  Var->setAccess(D->getAccess());
300
301  if (!D->isStaticDataMember())
302    Var->setUsed(D->isUsed(false));
303
304  // FIXME: In theory, we could have a previous declaration for variables that
305  // are not static data members.
306  bool Redeclaration = false;
307  // FIXME: having to fake up a LookupResult is dumb.
308  LookupResult Previous(SemaRef, Var->getDeclName(), Var->getLocation(),
309                        Sema::LookupOrdinaryName, Sema::ForRedeclaration);
310  if (D->isStaticDataMember())
311    SemaRef.LookupQualifiedName(Previous, Owner, false);
312  SemaRef.CheckVariableDeclaration(Var, Previous, Redeclaration);
313
314  if (D->isOutOfLine()) {
315    if (!D->isStaticDataMember())
316      D->getLexicalDeclContext()->addDecl(Var);
317    Owner->makeDeclVisibleInContext(Var);
318  } else {
319    Owner->addDecl(Var);
320    if (Owner->isFunctionOrMethod())
321      SemaRef.CurrentInstantiationScope->InstantiatedLocal(D, Var);
322  }
323  SemaRef.InstantiateAttrs(TemplateArgs, D, Var);
324
325  // Link instantiations of static data members back to the template from
326  // which they were instantiated.
327  if (Var->isStaticDataMember())
328    SemaRef.Context.setInstantiatedFromStaticDataMember(Var, D,
329                                                     TSK_ImplicitInstantiation);
330
331  if (Var->getAnyInitializer()) {
332    // We already have an initializer in the class.
333  } else if (D->getInit()) {
334    if (Var->isStaticDataMember() && !D->isOutOfLine())
335      SemaRef.PushExpressionEvaluationContext(Sema::Unevaluated);
336    else
337      SemaRef.PushExpressionEvaluationContext(Sema::PotentiallyEvaluated);
338
339    // Instantiate the initializer.
340    SourceLocation LParenLoc, RParenLoc;
341    ASTOwningVector<Expr*> InitArgs(SemaRef);
342    if (!InstantiateInitializer(SemaRef, D->getInit(), TemplateArgs, LParenLoc,
343                                InitArgs, RParenLoc)) {
344      bool TypeMayContainAuto = true;
345      // Attach the initializer to the declaration, if we have one.
346      if (InitArgs.size() == 0)
347        SemaRef.ActOnUninitializedDecl(Var, TypeMayContainAuto);
348      else if (D->hasCXXDirectInitializer()) {
349        // Add the direct initializer to the declaration.
350        SemaRef.AddCXXDirectInitializerToDecl(Var,
351                                              LParenLoc,
352                                              move_arg(InitArgs),
353                                              RParenLoc,
354                                              TypeMayContainAuto);
355      } else {
356        assert(InitArgs.size() == 1);
357        Expr *Init = InitArgs.take()[0];
358        SemaRef.AddInitializerToDecl(Var, Init, false, TypeMayContainAuto);
359      }
360    } else {
361      // FIXME: Not too happy about invalidating the declaration
362      // because of a bogus initializer.
363      Var->setInvalidDecl();
364    }
365
366    SemaRef.PopExpressionEvaluationContext();
367  } else if ((!Var->isStaticDataMember() || Var->isOutOfLine()) &&
368             !Var->isCXXForRangeDecl())
369    SemaRef.ActOnUninitializedDecl(Var, false);
370
371  // Diagnose unused local variables.
372  if (!Var->isInvalidDecl() && Owner->isFunctionOrMethod() && !Var->isUsed())
373    SemaRef.DiagnoseUnusedDecl(Var);
374
375  return Var;
376}
377
378Decl *TemplateDeclInstantiator::VisitAccessSpecDecl(AccessSpecDecl *D) {
379  AccessSpecDecl* AD
380    = AccessSpecDecl::Create(SemaRef.Context, D->getAccess(), Owner,
381                             D->getAccessSpecifierLoc(), D->getColonLoc());
382  Owner->addHiddenDecl(AD);
383  return AD;
384}
385
386Decl *TemplateDeclInstantiator::VisitFieldDecl(FieldDecl *D) {
387  bool Invalid = false;
388  TypeSourceInfo *DI = D->getTypeSourceInfo();
389  if (DI->getType()->isDependentType() ||
390      DI->getType()->isVariablyModifiedType())  {
391    DI = SemaRef.SubstType(DI, TemplateArgs,
392                           D->getLocation(), D->getDeclName());
393    if (!DI) {
394      DI = D->getTypeSourceInfo();
395      Invalid = true;
396    } else if (DI->getType()->isFunctionType()) {
397      // C++ [temp.arg.type]p3:
398      //   If a declaration acquires a function type through a type
399      //   dependent on a template-parameter and this causes a
400      //   declaration that does not use the syntactic form of a
401      //   function declarator to have function type, the program is
402      //   ill-formed.
403      SemaRef.Diag(D->getLocation(), diag::err_field_instantiates_to_function)
404        << DI->getType();
405      Invalid = true;
406    }
407  } else {
408    SemaRef.MarkDeclarationsReferencedInType(D->getLocation(), DI->getType());
409  }
410
411  Expr *BitWidth = D->getBitWidth();
412  if (Invalid)
413    BitWidth = 0;
414  else if (BitWidth) {
415    // The bit-width expression is not potentially evaluated.
416    EnterExpressionEvaluationContext Unevaluated(SemaRef, Sema::Unevaluated);
417
418    ExprResult InstantiatedBitWidth
419      = SemaRef.SubstExpr(BitWidth, TemplateArgs);
420    if (InstantiatedBitWidth.isInvalid()) {
421      Invalid = true;
422      BitWidth = 0;
423    } else
424      BitWidth = InstantiatedBitWidth.takeAs<Expr>();
425  }
426
427  FieldDecl *Field = SemaRef.CheckFieldDecl(D->getDeclName(),
428                                            DI->getType(), DI,
429                                            cast<RecordDecl>(Owner),
430                                            D->getLocation(),
431                                            D->isMutable(),
432                                            BitWidth,
433                                            D->getTypeSpecStartLoc(),
434                                            D->getAccess(),
435                                            0);
436  if (!Field) {
437    cast<Decl>(Owner)->setInvalidDecl();
438    return 0;
439  }
440
441  SemaRef.InstantiateAttrs(TemplateArgs, D, Field);
442
443  if (Invalid)
444    Field->setInvalidDecl();
445
446  if (!Field->getDeclName()) {
447    // Keep track of where this decl came from.
448    SemaRef.Context.setInstantiatedFromUnnamedFieldDecl(Field, D);
449  }
450  if (CXXRecordDecl *Parent= dyn_cast<CXXRecordDecl>(Field->getDeclContext())) {
451    if (Parent->isAnonymousStructOrUnion() &&
452        Parent->getRedeclContext()->isFunctionOrMethod())
453      SemaRef.CurrentInstantiationScope->InstantiatedLocal(D, Field);
454  }
455
456  Field->setImplicit(D->isImplicit());
457  Field->setAccess(D->getAccess());
458  Owner->addDecl(Field);
459
460  return Field;
461}
462
463Decl *TemplateDeclInstantiator::VisitIndirectFieldDecl(IndirectFieldDecl *D) {
464  NamedDecl **NamedChain =
465    new (SemaRef.Context)NamedDecl*[D->getChainingSize()];
466
467  int i = 0;
468  for (IndirectFieldDecl::chain_iterator PI =
469       D->chain_begin(), PE = D->chain_end();
470       PI != PE; ++PI) {
471    NamedDecl *Next = SemaRef.FindInstantiatedDecl(D->getLocation(), *PI,
472                                              TemplateArgs);
473    if (!Next)
474      return 0;
475
476    NamedChain[i++] = Next;
477  }
478
479  QualType T = cast<FieldDecl>(NamedChain[i-1])->getType();
480  IndirectFieldDecl* IndirectField
481    = IndirectFieldDecl::Create(SemaRef.Context, Owner, D->getLocation(),
482                                D->getIdentifier(), T,
483                                NamedChain, D->getChainingSize());
484
485
486  IndirectField->setImplicit(D->isImplicit());
487  IndirectField->setAccess(D->getAccess());
488  Owner->addDecl(IndirectField);
489  return IndirectField;
490}
491
492Decl *TemplateDeclInstantiator::VisitFriendDecl(FriendDecl *D) {
493  // Handle friend type expressions by simply substituting template
494  // parameters into the pattern type and checking the result.
495  if (TypeSourceInfo *Ty = D->getFriendType()) {
496    TypeSourceInfo *InstTy =
497      SemaRef.SubstType(Ty, TemplateArgs,
498                        D->getLocation(), DeclarationName());
499    if (!InstTy)
500      return 0;
501
502    FriendDecl *FD = SemaRef.CheckFriendTypeDecl(D->getFriendLoc(), InstTy);
503    if (!FD)
504      return 0;
505
506    FD->setAccess(AS_public);
507    FD->setUnsupportedFriend(D->isUnsupportedFriend());
508    Owner->addDecl(FD);
509    return FD;
510  }
511
512  NamedDecl *ND = D->getFriendDecl();
513  assert(ND && "friend decl must be a decl or a type!");
514
515  // All of the Visit implementations for the various potential friend
516  // declarations have to be carefully written to work for friend
517  // objects, with the most important detail being that the target
518  // decl should almost certainly not be placed in Owner.
519  Decl *NewND = Visit(ND);
520  if (!NewND) return 0;
521
522  FriendDecl *FD =
523    FriendDecl::Create(SemaRef.Context, Owner, D->getLocation(),
524                       cast<NamedDecl>(NewND), D->getFriendLoc());
525  FD->setAccess(AS_public);
526  FD->setUnsupportedFriend(D->isUnsupportedFriend());
527  Owner->addDecl(FD);
528  return FD;
529}
530
531Decl *TemplateDeclInstantiator::VisitStaticAssertDecl(StaticAssertDecl *D) {
532  Expr *AssertExpr = D->getAssertExpr();
533
534  // The expression in a static assertion is not potentially evaluated.
535  EnterExpressionEvaluationContext Unevaluated(SemaRef, Sema::Unevaluated);
536
537  ExprResult InstantiatedAssertExpr
538    = SemaRef.SubstExpr(AssertExpr, TemplateArgs);
539  if (InstantiatedAssertExpr.isInvalid())
540    return 0;
541
542  ExprResult Message(D->getMessage());
543  D->getMessage();
544  return SemaRef.ActOnStaticAssertDeclaration(D->getLocation(),
545                                              InstantiatedAssertExpr.get(),
546                                              Message.get(),
547                                              D->getRParenLoc());
548}
549
550Decl *TemplateDeclInstantiator::VisitEnumDecl(EnumDecl *D) {
551  EnumDecl *Enum = EnumDecl::Create(SemaRef.Context, Owner, D->getLocStart(),
552                                    D->getLocation(), D->getIdentifier(),
553                                    /*PrevDecl=*/0, D->isScoped(),
554                                    D->isScopedUsingClassTag(), D->isFixed());
555  if (D->isFixed()) {
556    if (TypeSourceInfo* TI = D->getIntegerTypeSourceInfo()) {
557      // If we have type source information for the underlying type, it means it
558      // has been explicitly set by the user. Perform substitution on it before
559      // moving on.
560      SourceLocation UnderlyingLoc = TI->getTypeLoc().getBeginLoc();
561      Enum->setIntegerTypeSourceInfo(SemaRef.SubstType(TI,
562                                                       TemplateArgs,
563                                                       UnderlyingLoc,
564                                                       DeclarationName()));
565
566      if (!Enum->getIntegerTypeSourceInfo())
567        Enum->setIntegerType(SemaRef.Context.IntTy);
568    }
569    else {
570      assert(!D->getIntegerType()->isDependentType()
571             && "Dependent type without type source info");
572      Enum->setIntegerType(D->getIntegerType());
573    }
574  }
575
576  SemaRef.InstantiateAttrs(TemplateArgs, D, Enum);
577
578  Enum->setInstantiationOfMemberEnum(D);
579  Enum->setAccess(D->getAccess());
580  if (SubstQualifier(D, Enum)) return 0;
581  Owner->addDecl(Enum);
582  Enum->startDefinition();
583
584  if (D->getDeclContext()->isFunctionOrMethod())
585    SemaRef.CurrentInstantiationScope->InstantiatedLocal(D, Enum);
586
587  llvm::SmallVector<Decl*, 4> Enumerators;
588
589  EnumConstantDecl *LastEnumConst = 0;
590  for (EnumDecl::enumerator_iterator EC = D->enumerator_begin(),
591         ECEnd = D->enumerator_end();
592       EC != ECEnd; ++EC) {
593    // The specified value for the enumerator.
594    ExprResult Value = SemaRef.Owned((Expr *)0);
595    if (Expr *UninstValue = EC->getInitExpr()) {
596      // The enumerator's value expression is not potentially evaluated.
597      EnterExpressionEvaluationContext Unevaluated(SemaRef,
598                                                   Sema::Unevaluated);
599
600      Value = SemaRef.SubstExpr(UninstValue, TemplateArgs);
601    }
602
603    // Drop the initial value and continue.
604    bool isInvalid = false;
605    if (Value.isInvalid()) {
606      Value = SemaRef.Owned((Expr *)0);
607      isInvalid = true;
608    }
609
610    EnumConstantDecl *EnumConst
611      = SemaRef.CheckEnumConstant(Enum, LastEnumConst,
612                                  EC->getLocation(), EC->getIdentifier(),
613                                  Value.get());
614
615    if (isInvalid) {
616      if (EnumConst)
617        EnumConst->setInvalidDecl();
618      Enum->setInvalidDecl();
619    }
620
621    if (EnumConst) {
622      SemaRef.InstantiateAttrs(TemplateArgs, *EC, EnumConst);
623
624      EnumConst->setAccess(Enum->getAccess());
625      Enum->addDecl(EnumConst);
626      Enumerators.push_back(EnumConst);
627      LastEnumConst = EnumConst;
628
629      if (D->getDeclContext()->isFunctionOrMethod()) {
630        // If the enumeration is within a function or method, record the enum
631        // constant as a local.
632        SemaRef.CurrentInstantiationScope->InstantiatedLocal(*EC, EnumConst);
633      }
634    }
635  }
636
637  // FIXME: Fixup LBraceLoc and RBraceLoc
638  // FIXME: Empty Scope and AttributeList (required to handle attribute packed).
639  SemaRef.ActOnEnumBody(Enum->getLocation(), SourceLocation(), SourceLocation(),
640                        Enum,
641                        Enumerators.data(), Enumerators.size(),
642                        0, 0);
643
644  return Enum;
645}
646
647Decl *TemplateDeclInstantiator::VisitEnumConstantDecl(EnumConstantDecl *D) {
648  assert(false && "EnumConstantDecls can only occur within EnumDecls.");
649  return 0;
650}
651
652Decl *TemplateDeclInstantiator::VisitClassTemplateDecl(ClassTemplateDecl *D) {
653  bool isFriend = (D->getFriendObjectKind() != Decl::FOK_None);
654
655  // Create a local instantiation scope for this class template, which
656  // will contain the instantiations of the template parameters.
657  LocalInstantiationScope Scope(SemaRef);
658  TemplateParameterList *TempParams = D->getTemplateParameters();
659  TemplateParameterList *InstParams = SubstTemplateParams(TempParams);
660  if (!InstParams)
661    return NULL;
662
663  CXXRecordDecl *Pattern = D->getTemplatedDecl();
664
665  // Instantiate the qualifier.  We have to do this first in case
666  // we're a friend declaration, because if we are then we need to put
667  // the new declaration in the appropriate context.
668  NestedNameSpecifierLoc QualifierLoc = Pattern->getQualifierLoc();
669  if (QualifierLoc) {
670    QualifierLoc = SemaRef.SubstNestedNameSpecifierLoc(QualifierLoc,
671                                                       TemplateArgs);
672    if (!QualifierLoc)
673      return 0;
674  }
675
676  CXXRecordDecl *PrevDecl = 0;
677  ClassTemplateDecl *PrevClassTemplate = 0;
678
679  if (!isFriend && Pattern->getPreviousDeclaration()) {
680    DeclContext::lookup_result Found = Owner->lookup(Pattern->getDeclName());
681    if (Found.first != Found.second) {
682      PrevClassTemplate = dyn_cast<ClassTemplateDecl>(*Found.first);
683      if (PrevClassTemplate)
684        PrevDecl = PrevClassTemplate->getTemplatedDecl();
685    }
686  }
687
688  // If this isn't a friend, then it's a member template, in which
689  // case we just want to build the instantiation in the
690  // specialization.  If it is a friend, we want to build it in
691  // the appropriate context.
692  DeclContext *DC = Owner;
693  if (isFriend) {
694    if (QualifierLoc) {
695      CXXScopeSpec SS;
696      SS.Adopt(QualifierLoc);
697      DC = SemaRef.computeDeclContext(SS);
698      if (!DC) return 0;
699    } else {
700      DC = SemaRef.FindInstantiatedContext(Pattern->getLocation(),
701                                           Pattern->getDeclContext(),
702                                           TemplateArgs);
703    }
704
705    // Look for a previous declaration of the template in the owning
706    // context.
707    LookupResult R(SemaRef, Pattern->getDeclName(), Pattern->getLocation(),
708                   Sema::LookupOrdinaryName, Sema::ForRedeclaration);
709    SemaRef.LookupQualifiedName(R, DC);
710
711    if (R.isSingleResult()) {
712      PrevClassTemplate = R.getAsSingle<ClassTemplateDecl>();
713      if (PrevClassTemplate)
714        PrevDecl = PrevClassTemplate->getTemplatedDecl();
715    }
716
717    if (!PrevClassTemplate && QualifierLoc) {
718      SemaRef.Diag(Pattern->getLocation(), diag::err_not_tag_in_scope)
719        << D->getTemplatedDecl()->getTagKind() << Pattern->getDeclName() << DC
720        << QualifierLoc.getSourceRange();
721      return 0;
722    }
723
724    bool AdoptedPreviousTemplateParams = false;
725    if (PrevClassTemplate) {
726      bool Complain = true;
727
728      // HACK: libstdc++ 4.2.1 contains an ill-formed friend class
729      // template for struct std::tr1::__detail::_Map_base, where the
730      // template parameters of the friend declaration don't match the
731      // template parameters of the original declaration. In this one
732      // case, we don't complain about the ill-formed friend
733      // declaration.
734      if (isFriend && Pattern->getIdentifier() &&
735          Pattern->getIdentifier()->isStr("_Map_base") &&
736          DC->isNamespace() &&
737          cast<NamespaceDecl>(DC)->getIdentifier() &&
738          cast<NamespaceDecl>(DC)->getIdentifier()->isStr("__detail")) {
739        DeclContext *DCParent = DC->getParent();
740        if (DCParent->isNamespace() &&
741            cast<NamespaceDecl>(DCParent)->getIdentifier() &&
742            cast<NamespaceDecl>(DCParent)->getIdentifier()->isStr("tr1")) {
743          DeclContext *DCParent2 = DCParent->getParent();
744          if (DCParent2->isNamespace() &&
745              cast<NamespaceDecl>(DCParent2)->getIdentifier() &&
746              cast<NamespaceDecl>(DCParent2)->getIdentifier()->isStr("std") &&
747              DCParent2->getParent()->isTranslationUnit())
748            Complain = false;
749        }
750      }
751
752      TemplateParameterList *PrevParams
753        = PrevClassTemplate->getTemplateParameters();
754
755      // Make sure the parameter lists match.
756      if (!SemaRef.TemplateParameterListsAreEqual(InstParams, PrevParams,
757                                                  Complain,
758                                                  Sema::TPL_TemplateMatch)) {
759        if (Complain)
760          return 0;
761
762        AdoptedPreviousTemplateParams = true;
763        InstParams = PrevParams;
764      }
765
766      // Do some additional validation, then merge default arguments
767      // from the existing declarations.
768      if (!AdoptedPreviousTemplateParams &&
769          SemaRef.CheckTemplateParameterList(InstParams, PrevParams,
770                                             Sema::TPC_ClassTemplate))
771        return 0;
772    }
773  }
774
775  CXXRecordDecl *RecordInst
776    = CXXRecordDecl::Create(SemaRef.Context, Pattern->getTagKind(), DC,
777                            Pattern->getLocStart(), Pattern->getLocation(),
778                            Pattern->getIdentifier(), PrevDecl,
779                            /*DelayTypeCreation=*/true);
780
781  if (QualifierLoc)
782    RecordInst->setQualifierInfo(QualifierLoc);
783
784  ClassTemplateDecl *Inst
785    = ClassTemplateDecl::Create(SemaRef.Context, DC, D->getLocation(),
786                                D->getIdentifier(), InstParams, RecordInst,
787                                PrevClassTemplate);
788  RecordInst->setDescribedClassTemplate(Inst);
789
790  if (isFriend) {
791    if (PrevClassTemplate)
792      Inst->setAccess(PrevClassTemplate->getAccess());
793    else
794      Inst->setAccess(D->getAccess());
795
796    Inst->setObjectOfFriendDecl(PrevClassTemplate != 0);
797    // TODO: do we want to track the instantiation progeny of this
798    // friend target decl?
799  } else {
800    Inst->setAccess(D->getAccess());
801    if (!PrevClassTemplate)
802      Inst->setInstantiatedFromMemberTemplate(D);
803  }
804
805  // Trigger creation of the type for the instantiation.
806  SemaRef.Context.getInjectedClassNameType(RecordInst,
807                                    Inst->getInjectedClassNameSpecialization());
808
809  // Finish handling of friends.
810  if (isFriend) {
811    DC->makeDeclVisibleInContext(Inst, /*Recoverable*/ false);
812    return Inst;
813  }
814
815  Owner->addDecl(Inst);
816
817  if (!PrevClassTemplate) {
818    // Queue up any out-of-line partial specializations of this member
819    // class template; the client will force their instantiation once
820    // the enclosing class has been instantiated.
821    llvm::SmallVector<ClassTemplatePartialSpecializationDecl *, 4> PartialSpecs;
822    D->getPartialSpecializations(PartialSpecs);
823    for (unsigned I = 0, N = PartialSpecs.size(); I != N; ++I)
824      if (PartialSpecs[I]->isOutOfLine())
825        OutOfLinePartialSpecs.push_back(std::make_pair(Inst, PartialSpecs[I]));
826  }
827
828  return Inst;
829}
830
831Decl *
832TemplateDeclInstantiator::VisitClassTemplatePartialSpecializationDecl(
833                                   ClassTemplatePartialSpecializationDecl *D) {
834  ClassTemplateDecl *ClassTemplate = D->getSpecializedTemplate();
835
836  // Lookup the already-instantiated declaration in the instantiation
837  // of the class template and return that.
838  DeclContext::lookup_result Found
839    = Owner->lookup(ClassTemplate->getDeclName());
840  if (Found.first == Found.second)
841    return 0;
842
843  ClassTemplateDecl *InstClassTemplate
844    = dyn_cast<ClassTemplateDecl>(*Found.first);
845  if (!InstClassTemplate)
846    return 0;
847
848  if (ClassTemplatePartialSpecializationDecl *Result
849        = InstClassTemplate->findPartialSpecInstantiatedFromMember(D))
850    return Result;
851
852  return InstantiateClassTemplatePartialSpecialization(InstClassTemplate, D);
853}
854
855Decl *
856TemplateDeclInstantiator::VisitFunctionTemplateDecl(FunctionTemplateDecl *D) {
857  // Create a local instantiation scope for this function template, which
858  // will contain the instantiations of the template parameters and then get
859  // merged with the local instantiation scope for the function template
860  // itself.
861  LocalInstantiationScope Scope(SemaRef);
862
863  TemplateParameterList *TempParams = D->getTemplateParameters();
864  TemplateParameterList *InstParams = SubstTemplateParams(TempParams);
865  if (!InstParams)
866    return NULL;
867
868  FunctionDecl *Instantiated = 0;
869  if (CXXMethodDecl *DMethod = dyn_cast<CXXMethodDecl>(D->getTemplatedDecl()))
870    Instantiated = cast_or_null<FunctionDecl>(VisitCXXMethodDecl(DMethod,
871                                                                 InstParams));
872  else
873    Instantiated = cast_or_null<FunctionDecl>(VisitFunctionDecl(
874                                                          D->getTemplatedDecl(),
875                                                                InstParams));
876
877  if (!Instantiated)
878    return 0;
879
880  Instantiated->setAccess(D->getAccess());
881
882  // Link the instantiated function template declaration to the function
883  // template from which it was instantiated.
884  FunctionTemplateDecl *InstTemplate
885    = Instantiated->getDescribedFunctionTemplate();
886  InstTemplate->setAccess(D->getAccess());
887  assert(InstTemplate &&
888         "VisitFunctionDecl/CXXMethodDecl didn't create a template!");
889
890  bool isFriend = (InstTemplate->getFriendObjectKind() != Decl::FOK_None);
891
892  // Link the instantiation back to the pattern *unless* this is a
893  // non-definition friend declaration.
894  if (!InstTemplate->getInstantiatedFromMemberTemplate() &&
895      !(isFriend && !D->getTemplatedDecl()->isThisDeclarationADefinition()))
896    InstTemplate->setInstantiatedFromMemberTemplate(D);
897
898  // Make declarations visible in the appropriate context.
899  if (!isFriend)
900    Owner->addDecl(InstTemplate);
901
902  return InstTemplate;
903}
904
905Decl *TemplateDeclInstantiator::VisitCXXRecordDecl(CXXRecordDecl *D) {
906  CXXRecordDecl *PrevDecl = 0;
907  if (D->isInjectedClassName())
908    PrevDecl = cast<CXXRecordDecl>(Owner);
909  else if (D->getPreviousDeclaration()) {
910    NamedDecl *Prev = SemaRef.FindInstantiatedDecl(D->getLocation(),
911                                                   D->getPreviousDeclaration(),
912                                                   TemplateArgs);
913    if (!Prev) return 0;
914    PrevDecl = cast<CXXRecordDecl>(Prev);
915  }
916
917  CXXRecordDecl *Record
918    = CXXRecordDecl::Create(SemaRef.Context, D->getTagKind(), Owner,
919                            D->getLocStart(), D->getLocation(),
920                            D->getIdentifier(), PrevDecl);
921
922  // Substitute the nested name specifier, if any.
923  if (SubstQualifier(D, Record))
924    return 0;
925
926  Record->setImplicit(D->isImplicit());
927  // FIXME: Check against AS_none is an ugly hack to work around the issue that
928  // the tag decls introduced by friend class declarations don't have an access
929  // specifier. Remove once this area of the code gets sorted out.
930  if (D->getAccess() != AS_none)
931    Record->setAccess(D->getAccess());
932  if (!D->isInjectedClassName())
933    Record->setInstantiationOfMemberClass(D, TSK_ImplicitInstantiation);
934
935  // If the original function was part of a friend declaration,
936  // inherit its namespace state.
937  if (Decl::FriendObjectKind FOK = D->getFriendObjectKind())
938    Record->setObjectOfFriendDecl(FOK == Decl::FOK_Declared);
939
940  // Make sure that anonymous structs and unions are recorded.
941  if (D->isAnonymousStructOrUnion()) {
942    Record->setAnonymousStructOrUnion(true);
943    if (Record->getDeclContext()->getRedeclContext()->isFunctionOrMethod())
944      SemaRef.CurrentInstantiationScope->InstantiatedLocal(D, Record);
945  }
946
947  Owner->addDecl(Record);
948  return Record;
949}
950
951/// Normal class members are of more specific types and therefore
952/// don't make it here.  This function serves two purposes:
953///   1) instantiating function templates
954///   2) substituting friend declarations
955/// FIXME: preserve function definitions in case #2
956Decl *TemplateDeclInstantiator::VisitFunctionDecl(FunctionDecl *D,
957                                       TemplateParameterList *TemplateParams) {
958  // Check whether there is already a function template specialization for
959  // this declaration.
960  FunctionTemplateDecl *FunctionTemplate = D->getDescribedFunctionTemplate();
961  void *InsertPos = 0;
962  if (FunctionTemplate && !TemplateParams) {
963    std::pair<const TemplateArgument *, unsigned> Innermost
964      = TemplateArgs.getInnermost();
965
966    FunctionDecl *SpecFunc
967      = FunctionTemplate->findSpecialization(Innermost.first, Innermost.second,
968                                             InsertPos);
969
970    // If we already have a function template specialization, return it.
971    if (SpecFunc)
972      return SpecFunc;
973  }
974
975  bool isFriend;
976  if (FunctionTemplate)
977    isFriend = (FunctionTemplate->getFriendObjectKind() != Decl::FOK_None);
978  else
979    isFriend = (D->getFriendObjectKind() != Decl::FOK_None);
980
981  bool MergeWithParentScope = (TemplateParams != 0) ||
982    Owner->isFunctionOrMethod() ||
983    !(isa<Decl>(Owner) &&
984      cast<Decl>(Owner)->isDefinedOutsideFunctionOrMethod());
985  LocalInstantiationScope Scope(SemaRef, MergeWithParentScope);
986
987  llvm::SmallVector<ParmVarDecl *, 4> Params;
988  TypeSourceInfo *TInfo = D->getTypeSourceInfo();
989  TInfo = SubstFunctionType(D, Params);
990  if (!TInfo)
991    return 0;
992  QualType T = TInfo->getType();
993
994  NestedNameSpecifierLoc QualifierLoc = D->getQualifierLoc();
995  if (QualifierLoc) {
996    QualifierLoc = SemaRef.SubstNestedNameSpecifierLoc(QualifierLoc,
997                                                       TemplateArgs);
998    if (!QualifierLoc)
999      return 0;
1000  }
1001
1002  // If we're instantiating a local function declaration, put the result
1003  // in the owner;  otherwise we need to find the instantiated context.
1004  DeclContext *DC;
1005  if (D->getDeclContext()->isFunctionOrMethod())
1006    DC = Owner;
1007  else if (isFriend && QualifierLoc) {
1008    CXXScopeSpec SS;
1009    SS.Adopt(QualifierLoc);
1010    DC = SemaRef.computeDeclContext(SS);
1011    if (!DC) return 0;
1012  } else {
1013    DC = SemaRef.FindInstantiatedContext(D->getLocation(), D->getDeclContext(),
1014                                         TemplateArgs);
1015  }
1016
1017  FunctionDecl *Function =
1018      FunctionDecl::Create(SemaRef.Context, DC, D->getInnerLocStart(),
1019                           D->getLocation(), D->getDeclName(), T, TInfo,
1020                           D->getStorageClass(), D->getStorageClassAsWritten(),
1021                           D->isInlineSpecified(), D->hasWrittenPrototype());
1022
1023  if (QualifierLoc)
1024    Function->setQualifierInfo(QualifierLoc);
1025
1026  DeclContext *LexicalDC = Owner;
1027  if (!isFriend && D->isOutOfLine()) {
1028    assert(D->getDeclContext()->isFileContext());
1029    LexicalDC = D->getDeclContext();
1030  }
1031
1032  Function->setLexicalDeclContext(LexicalDC);
1033
1034  // Attach the parameters
1035  for (unsigned P = 0; P < Params.size(); ++P)
1036    if (Params[P])
1037      Params[P]->setOwningFunction(Function);
1038  Function->setParams(Params.data(), Params.size());
1039
1040  SourceLocation InstantiateAtPOI;
1041  if (TemplateParams) {
1042    // Our resulting instantiation is actually a function template, since we
1043    // are substituting only the outer template parameters. For example, given
1044    //
1045    //   template<typename T>
1046    //   struct X {
1047    //     template<typename U> friend void f(T, U);
1048    //   };
1049    //
1050    //   X<int> x;
1051    //
1052    // We are instantiating the friend function template "f" within X<int>,
1053    // which means substituting int for T, but leaving "f" as a friend function
1054    // template.
1055    // Build the function template itself.
1056    FunctionTemplate = FunctionTemplateDecl::Create(SemaRef.Context, DC,
1057                                                    Function->getLocation(),
1058                                                    Function->getDeclName(),
1059                                                    TemplateParams, Function);
1060    Function->setDescribedFunctionTemplate(FunctionTemplate);
1061
1062    FunctionTemplate->setLexicalDeclContext(LexicalDC);
1063
1064    if (isFriend && D->isThisDeclarationADefinition()) {
1065      // TODO: should we remember this connection regardless of whether
1066      // the friend declaration provided a body?
1067      FunctionTemplate->setInstantiatedFromMemberTemplate(
1068                                           D->getDescribedFunctionTemplate());
1069    }
1070  } else if (FunctionTemplate) {
1071    // Record this function template specialization.
1072    std::pair<const TemplateArgument *, unsigned> Innermost
1073      = TemplateArgs.getInnermost();
1074    Function->setFunctionTemplateSpecialization(FunctionTemplate,
1075                            TemplateArgumentList::CreateCopy(SemaRef.Context,
1076                                                             Innermost.first,
1077                                                             Innermost.second),
1078                                                InsertPos);
1079  } else if (isFriend && D->isThisDeclarationADefinition()) {
1080    // TODO: should we remember this connection regardless of whether
1081    // the friend declaration provided a body?
1082    Function->setInstantiationOfMemberFunction(D, TSK_ImplicitInstantiation);
1083  }
1084
1085  if (InitFunctionInstantiation(Function, D))
1086    Function->setInvalidDecl();
1087
1088  bool Redeclaration = false;
1089  bool isExplicitSpecialization = false;
1090
1091  LookupResult Previous(SemaRef, Function->getDeclName(), SourceLocation(),
1092                        Sema::LookupOrdinaryName, Sema::ForRedeclaration);
1093
1094  if (DependentFunctionTemplateSpecializationInfo *Info
1095        = D->getDependentSpecializationInfo()) {
1096    assert(isFriend && "non-friend has dependent specialization info?");
1097
1098    // This needs to be set now for future sanity.
1099    Function->setObjectOfFriendDecl(/*HasPrevious*/ true);
1100
1101    // Instantiate the explicit template arguments.
1102    TemplateArgumentListInfo ExplicitArgs(Info->getLAngleLoc(),
1103                                          Info->getRAngleLoc());
1104    if (SemaRef.Subst(Info->getTemplateArgs(), Info->getNumTemplateArgs(),
1105                      ExplicitArgs, TemplateArgs))
1106      return 0;
1107
1108    // Map the candidate templates to their instantiations.
1109    for (unsigned I = 0, E = Info->getNumTemplates(); I != E; ++I) {
1110      Decl *Temp = SemaRef.FindInstantiatedDecl(D->getLocation(),
1111                                                Info->getTemplate(I),
1112                                                TemplateArgs);
1113      if (!Temp) return 0;
1114
1115      Previous.addDecl(cast<FunctionTemplateDecl>(Temp));
1116    }
1117
1118    if (SemaRef.CheckFunctionTemplateSpecialization(Function,
1119                                                    &ExplicitArgs,
1120                                                    Previous))
1121      Function->setInvalidDecl();
1122
1123    isExplicitSpecialization = true;
1124
1125  } else if (TemplateParams || !FunctionTemplate) {
1126    // Look only into the namespace where the friend would be declared to
1127    // find a previous declaration. This is the innermost enclosing namespace,
1128    // as described in ActOnFriendFunctionDecl.
1129    SemaRef.LookupQualifiedName(Previous, DC);
1130
1131    // In C++, the previous declaration we find might be a tag type
1132    // (class or enum). In this case, the new declaration will hide the
1133    // tag type. Note that this does does not apply if we're declaring a
1134    // typedef (C++ [dcl.typedef]p4).
1135    if (Previous.isSingleTagDecl())
1136      Previous.clear();
1137  }
1138
1139  SemaRef.CheckFunctionDeclaration(/*Scope*/ 0, Function, Previous,
1140                                   isExplicitSpecialization, Redeclaration);
1141
1142  NamedDecl *PrincipalDecl = (TemplateParams
1143                              ? cast<NamedDecl>(FunctionTemplate)
1144                              : Function);
1145
1146  // If the original function was part of a friend declaration,
1147  // inherit its namespace state and add it to the owner.
1148  if (isFriend) {
1149    NamedDecl *PrevDecl;
1150    if (TemplateParams)
1151      PrevDecl = FunctionTemplate->getPreviousDeclaration();
1152    else
1153      PrevDecl = Function->getPreviousDeclaration();
1154
1155    PrincipalDecl->setObjectOfFriendDecl(PrevDecl != 0);
1156    DC->makeDeclVisibleInContext(PrincipalDecl, /*Recoverable=*/ false);
1157
1158    bool queuedInstantiation = false;
1159
1160    if (!SemaRef.getLangOptions().CPlusPlus0x &&
1161        D->isThisDeclarationADefinition()) {
1162      // Check for a function body.
1163      const FunctionDecl *Definition = 0;
1164      if (Function->hasBody(Definition) &&
1165          Definition->getTemplateSpecializationKind() == TSK_Undeclared) {
1166        SemaRef.Diag(Function->getLocation(), diag::err_redefinition)
1167          << Function->getDeclName();
1168        SemaRef.Diag(Definition->getLocation(), diag::note_previous_definition);
1169        Function->setInvalidDecl();
1170      }
1171      // Check for redefinitions due to other instantiations of this or
1172      // a similar friend function.
1173      else for (FunctionDecl::redecl_iterator R = Function->redecls_begin(),
1174                                           REnd = Function->redecls_end();
1175                R != REnd; ++R) {
1176        if (*R == Function)
1177          continue;
1178        switch (R->getFriendObjectKind()) {
1179        case Decl::FOK_None:
1180          if (!queuedInstantiation && R->isUsed(false)) {
1181            if (MemberSpecializationInfo *MSInfo
1182                = Function->getMemberSpecializationInfo()) {
1183              if (MSInfo->getPointOfInstantiation().isInvalid()) {
1184                SourceLocation Loc = R->getLocation(); // FIXME
1185                MSInfo->setPointOfInstantiation(Loc);
1186                SemaRef.PendingLocalImplicitInstantiations.push_back(
1187                                                 std::make_pair(Function, Loc));
1188                queuedInstantiation = true;
1189              }
1190            }
1191          }
1192          break;
1193        default:
1194          if (const FunctionDecl *RPattern
1195              = R->getTemplateInstantiationPattern())
1196            if (RPattern->hasBody(RPattern)) {
1197              SemaRef.Diag(Function->getLocation(), diag::err_redefinition)
1198                << Function->getDeclName();
1199              SemaRef.Diag(R->getLocation(), diag::note_previous_definition);
1200              Function->setInvalidDecl();
1201              break;
1202            }
1203        }
1204      }
1205    }
1206  }
1207
1208  if (Function->isOverloadedOperator() && !DC->isRecord() &&
1209      PrincipalDecl->isInIdentifierNamespace(Decl::IDNS_Ordinary))
1210    PrincipalDecl->setNonMemberOperator();
1211
1212  return Function;
1213}
1214
1215Decl *
1216TemplateDeclInstantiator::VisitCXXMethodDecl(CXXMethodDecl *D,
1217                                      TemplateParameterList *TemplateParams) {
1218  FunctionTemplateDecl *FunctionTemplate = D->getDescribedFunctionTemplate();
1219  void *InsertPos = 0;
1220  if (FunctionTemplate && !TemplateParams) {
1221    // We are creating a function template specialization from a function
1222    // template. Check whether there is already a function template
1223    // specialization for this particular set of template arguments.
1224    std::pair<const TemplateArgument *, unsigned> Innermost
1225      = TemplateArgs.getInnermost();
1226
1227    FunctionDecl *SpecFunc
1228      = FunctionTemplate->findSpecialization(Innermost.first, Innermost.second,
1229                                             InsertPos);
1230
1231    // If we already have a function template specialization, return it.
1232    if (SpecFunc)
1233      return SpecFunc;
1234  }
1235
1236  bool isFriend;
1237  if (FunctionTemplate)
1238    isFriend = (FunctionTemplate->getFriendObjectKind() != Decl::FOK_None);
1239  else
1240    isFriend = (D->getFriendObjectKind() != Decl::FOK_None);
1241
1242  bool MergeWithParentScope = (TemplateParams != 0) ||
1243    !(isa<Decl>(Owner) &&
1244      cast<Decl>(Owner)->isDefinedOutsideFunctionOrMethod());
1245  LocalInstantiationScope Scope(SemaRef, MergeWithParentScope);
1246
1247  // Instantiate enclosing template arguments for friends.
1248  llvm::SmallVector<TemplateParameterList *, 4> TempParamLists;
1249  unsigned NumTempParamLists = 0;
1250  if (isFriend && (NumTempParamLists = D->getNumTemplateParameterLists())) {
1251    TempParamLists.set_size(NumTempParamLists);
1252    for (unsigned I = 0; I != NumTempParamLists; ++I) {
1253      TemplateParameterList *TempParams = D->getTemplateParameterList(I);
1254      TemplateParameterList *InstParams = SubstTemplateParams(TempParams);
1255      if (!InstParams)
1256        return NULL;
1257      TempParamLists[I] = InstParams;
1258    }
1259  }
1260
1261  llvm::SmallVector<ParmVarDecl *, 4> Params;
1262  TypeSourceInfo *TInfo = D->getTypeSourceInfo();
1263  TInfo = SubstFunctionType(D, Params);
1264  if (!TInfo)
1265    return 0;
1266  QualType T = TInfo->getType();
1267
1268  // \brief If the type of this function, after ignoring parentheses,
1269  // is not *directly* a function type, then we're instantiating a function
1270  // that was declared via a typedef, e.g.,
1271  //
1272  //   typedef int functype(int, int);
1273  //   functype func;
1274  //
1275  // In this case, we'll just go instantiate the ParmVarDecls that we
1276  // synthesized in the method declaration.
1277  if (!isa<FunctionProtoType>(T.IgnoreParens())) {
1278    assert(!Params.size() && "Instantiating type could not yield parameters");
1279    llvm::SmallVector<QualType, 4> ParamTypes;
1280    if (SemaRef.SubstParmTypes(D->getLocation(), D->param_begin(),
1281                               D->getNumParams(), TemplateArgs, ParamTypes,
1282                               &Params))
1283      return 0;
1284  }
1285
1286  NestedNameSpecifierLoc QualifierLoc = D->getQualifierLoc();
1287  if (QualifierLoc) {
1288    QualifierLoc = SemaRef.SubstNestedNameSpecifierLoc(QualifierLoc,
1289                                                 TemplateArgs);
1290    if (!QualifierLoc)
1291      return 0;
1292  }
1293
1294  DeclContext *DC = Owner;
1295  if (isFriend) {
1296    if (QualifierLoc) {
1297      CXXScopeSpec SS;
1298      SS.Adopt(QualifierLoc);
1299      DC = SemaRef.computeDeclContext(SS);
1300
1301      if (DC && SemaRef.RequireCompleteDeclContext(SS, DC))
1302        return 0;
1303    } else {
1304      DC = SemaRef.FindInstantiatedContext(D->getLocation(),
1305                                           D->getDeclContext(),
1306                                           TemplateArgs);
1307    }
1308    if (!DC) return 0;
1309  }
1310
1311  // Build the instantiated method declaration.
1312  CXXRecordDecl *Record = cast<CXXRecordDecl>(DC);
1313  CXXMethodDecl *Method = 0;
1314
1315  SourceLocation StartLoc = D->getInnerLocStart();
1316  DeclarationNameInfo NameInfo
1317    = SemaRef.SubstDeclarationNameInfo(D->getNameInfo(), TemplateArgs);
1318  if (CXXConstructorDecl *Constructor = dyn_cast<CXXConstructorDecl>(D)) {
1319    Method = CXXConstructorDecl::Create(SemaRef.Context, Record,
1320                                        StartLoc, NameInfo, T, TInfo,
1321                                        Constructor->isExplicit(),
1322                                        Constructor->isInlineSpecified(),
1323                                        false);
1324  } else if (CXXDestructorDecl *Destructor = dyn_cast<CXXDestructorDecl>(D)) {
1325    Method = CXXDestructorDecl::Create(SemaRef.Context, Record,
1326                                       StartLoc, NameInfo, T, TInfo,
1327                                       Destructor->isInlineSpecified(),
1328                                       false);
1329  } else if (CXXConversionDecl *Conversion = dyn_cast<CXXConversionDecl>(D)) {
1330    Method = CXXConversionDecl::Create(SemaRef.Context, Record,
1331                                       StartLoc, NameInfo, T, TInfo,
1332                                       Conversion->isInlineSpecified(),
1333                                       Conversion->isExplicit(),
1334                                       Conversion->getLocEnd());
1335  } else {
1336    Method = CXXMethodDecl::Create(SemaRef.Context, Record,
1337                                   StartLoc, NameInfo, T, TInfo,
1338                                   D->isStatic(),
1339                                   D->getStorageClassAsWritten(),
1340                                   D->isInlineSpecified(),
1341                                   D->getLocEnd());
1342  }
1343
1344  if (QualifierLoc)
1345    Method->setQualifierInfo(QualifierLoc);
1346
1347  if (TemplateParams) {
1348    // Our resulting instantiation is actually a function template, since we
1349    // are substituting only the outer template parameters. For example, given
1350    //
1351    //   template<typename T>
1352    //   struct X {
1353    //     template<typename U> void f(T, U);
1354    //   };
1355    //
1356    //   X<int> x;
1357    //
1358    // We are instantiating the member template "f" within X<int>, which means
1359    // substituting int for T, but leaving "f" as a member function template.
1360    // Build the function template itself.
1361    FunctionTemplate = FunctionTemplateDecl::Create(SemaRef.Context, Record,
1362                                                    Method->getLocation(),
1363                                                    Method->getDeclName(),
1364                                                    TemplateParams, Method);
1365    if (isFriend) {
1366      FunctionTemplate->setLexicalDeclContext(Owner);
1367      FunctionTemplate->setObjectOfFriendDecl(true);
1368    } else if (D->isOutOfLine())
1369      FunctionTemplate->setLexicalDeclContext(D->getLexicalDeclContext());
1370    Method->setDescribedFunctionTemplate(FunctionTemplate);
1371  } else if (FunctionTemplate) {
1372    // Record this function template specialization.
1373    std::pair<const TemplateArgument *, unsigned> Innermost
1374      = TemplateArgs.getInnermost();
1375    Method->setFunctionTemplateSpecialization(FunctionTemplate,
1376                         TemplateArgumentList::CreateCopy(SemaRef.Context,
1377                                                          Innermost.first,
1378                                                          Innermost.second),
1379                                              InsertPos);
1380  } else if (!isFriend) {
1381    // Record that this is an instantiation of a member function.
1382    Method->setInstantiationOfMemberFunction(D, TSK_ImplicitInstantiation);
1383  }
1384
1385  // If we are instantiating a member function defined
1386  // out-of-line, the instantiation will have the same lexical
1387  // context (which will be a namespace scope) as the template.
1388  if (isFriend) {
1389    if (NumTempParamLists)
1390      Method->setTemplateParameterListsInfo(SemaRef.Context,
1391                                            NumTempParamLists,
1392                                            TempParamLists.data());
1393
1394    Method->setLexicalDeclContext(Owner);
1395    Method->setObjectOfFriendDecl(true);
1396  } else if (D->isOutOfLine())
1397    Method->setLexicalDeclContext(D->getLexicalDeclContext());
1398
1399  // Attach the parameters
1400  for (unsigned P = 0; P < Params.size(); ++P)
1401    Params[P]->setOwningFunction(Method);
1402  Method->setParams(Params.data(), Params.size());
1403
1404  if (InitMethodInstantiation(Method, D))
1405    Method->setInvalidDecl();
1406
1407  LookupResult Previous(SemaRef, NameInfo, Sema::LookupOrdinaryName,
1408                        Sema::ForRedeclaration);
1409
1410  if (!FunctionTemplate || TemplateParams || isFriend) {
1411    SemaRef.LookupQualifiedName(Previous, Record);
1412
1413    // In C++, the previous declaration we find might be a tag type
1414    // (class or enum). In this case, the new declaration will hide the
1415    // tag type. Note that this does does not apply if we're declaring a
1416    // typedef (C++ [dcl.typedef]p4).
1417    if (Previous.isSingleTagDecl())
1418      Previous.clear();
1419  }
1420
1421  bool Redeclaration = false;
1422  SemaRef.CheckFunctionDeclaration(0, Method, Previous, false, Redeclaration);
1423
1424  if (D->isPure())
1425    SemaRef.CheckPureMethod(Method, SourceRange());
1426
1427  Method->setAccess(D->getAccess());
1428
1429  SemaRef.CheckOverrideControl(Method);
1430
1431  if (FunctionTemplate) {
1432    // If there's a function template, let our caller handle it.
1433  } else if (Method->isInvalidDecl() && !Previous.empty()) {
1434    // Don't hide a (potentially) valid declaration with an invalid one.
1435  } else {
1436    NamedDecl *DeclToAdd = (TemplateParams
1437                            ? cast<NamedDecl>(FunctionTemplate)
1438                            : Method);
1439    if (isFriend)
1440      Record->makeDeclVisibleInContext(DeclToAdd);
1441    else
1442      Owner->addDecl(DeclToAdd);
1443  }
1444
1445  return Method;
1446}
1447
1448Decl *TemplateDeclInstantiator::VisitCXXConstructorDecl(CXXConstructorDecl *D) {
1449  return VisitCXXMethodDecl(D);
1450}
1451
1452Decl *TemplateDeclInstantiator::VisitCXXDestructorDecl(CXXDestructorDecl *D) {
1453  return VisitCXXMethodDecl(D);
1454}
1455
1456Decl *TemplateDeclInstantiator::VisitCXXConversionDecl(CXXConversionDecl *D) {
1457  return VisitCXXMethodDecl(D);
1458}
1459
1460ParmVarDecl *TemplateDeclInstantiator::VisitParmVarDecl(ParmVarDecl *D) {
1461  return SemaRef.SubstParmVarDecl(D, TemplateArgs, llvm::Optional<unsigned>());
1462}
1463
1464Decl *TemplateDeclInstantiator::VisitTemplateTypeParmDecl(
1465                                                    TemplateTypeParmDecl *D) {
1466  // TODO: don't always clone when decls are refcounted.
1467  const Type* T = D->getTypeForDecl();
1468  assert(T->isTemplateTypeParmType());
1469  const TemplateTypeParmType *TTPT = T->getAs<TemplateTypeParmType>();
1470
1471  TemplateTypeParmDecl *Inst =
1472    TemplateTypeParmDecl::Create(SemaRef.Context, Owner,
1473                                 D->getLocStart(), D->getLocation(),
1474                                 TTPT->getDepth() - TemplateArgs.getNumLevels(),
1475                                 TTPT->getIndex(), D->getIdentifier(),
1476                                 D->wasDeclaredWithTypename(),
1477                                 D->isParameterPack());
1478  Inst->setAccess(AS_public);
1479
1480  if (D->hasDefaultArgument())
1481    Inst->setDefaultArgument(D->getDefaultArgumentInfo(), false);
1482
1483  // Introduce this template parameter's instantiation into the instantiation
1484  // scope.
1485  SemaRef.CurrentInstantiationScope->InstantiatedLocal(D, Inst);
1486
1487  return Inst;
1488}
1489
1490Decl *TemplateDeclInstantiator::VisitNonTypeTemplateParmDecl(
1491                                                 NonTypeTemplateParmDecl *D) {
1492  // Substitute into the type of the non-type template parameter.
1493  TypeLoc TL = D->getTypeSourceInfo()->getTypeLoc();
1494  llvm::SmallVector<TypeSourceInfo *, 4> ExpandedParameterPackTypesAsWritten;
1495  llvm::SmallVector<QualType, 4> ExpandedParameterPackTypes;
1496  bool IsExpandedParameterPack = false;
1497  TypeSourceInfo *DI;
1498  QualType T;
1499  bool Invalid = false;
1500
1501  if (D->isExpandedParameterPack()) {
1502    // The non-type template parameter pack is an already-expanded pack
1503    // expansion of types. Substitute into each of the expanded types.
1504    ExpandedParameterPackTypes.reserve(D->getNumExpansionTypes());
1505    ExpandedParameterPackTypesAsWritten.reserve(D->getNumExpansionTypes());
1506    for (unsigned I = 0, N = D->getNumExpansionTypes(); I != N; ++I) {
1507      TypeSourceInfo *NewDI =SemaRef.SubstType(D->getExpansionTypeSourceInfo(I),
1508                                               TemplateArgs,
1509                                               D->getLocation(),
1510                                               D->getDeclName());
1511      if (!NewDI)
1512        return 0;
1513
1514      ExpandedParameterPackTypesAsWritten.push_back(NewDI);
1515      QualType NewT =SemaRef.CheckNonTypeTemplateParameterType(NewDI->getType(),
1516                                                              D->getLocation());
1517      if (NewT.isNull())
1518        return 0;
1519      ExpandedParameterPackTypes.push_back(NewT);
1520    }
1521
1522    IsExpandedParameterPack = true;
1523    DI = D->getTypeSourceInfo();
1524    T = DI->getType();
1525  } else if (isa<PackExpansionTypeLoc>(TL)) {
1526    // The non-type template parameter pack's type is a pack expansion of types.
1527    // Determine whether we need to expand this parameter pack into separate
1528    // types.
1529    PackExpansionTypeLoc Expansion = cast<PackExpansionTypeLoc>(TL);
1530    TypeLoc Pattern = Expansion.getPatternLoc();
1531    llvm::SmallVector<UnexpandedParameterPack, 2> Unexpanded;
1532    SemaRef.collectUnexpandedParameterPacks(Pattern, Unexpanded);
1533
1534    // Determine whether the set of unexpanded parameter packs can and should
1535    // be expanded.
1536    bool Expand = true;
1537    bool RetainExpansion = false;
1538    llvm::Optional<unsigned> OrigNumExpansions
1539      = Expansion.getTypePtr()->getNumExpansions();
1540    llvm::Optional<unsigned> NumExpansions = OrigNumExpansions;
1541    if (SemaRef.CheckParameterPacksForExpansion(Expansion.getEllipsisLoc(),
1542                                                Pattern.getSourceRange(),
1543                                                Unexpanded.data(),
1544                                                Unexpanded.size(),
1545                                                TemplateArgs,
1546                                                Expand, RetainExpansion,
1547                                                NumExpansions))
1548      return 0;
1549
1550    if (Expand) {
1551      for (unsigned I = 0; I != *NumExpansions; ++I) {
1552        Sema::ArgumentPackSubstitutionIndexRAII SubstIndex(SemaRef, I);
1553        TypeSourceInfo *NewDI = SemaRef.SubstType(Pattern, TemplateArgs,
1554                                                  D->getLocation(),
1555                                                  D->getDeclName());
1556        if (!NewDI)
1557          return 0;
1558
1559        ExpandedParameterPackTypesAsWritten.push_back(NewDI);
1560        QualType NewT = SemaRef.CheckNonTypeTemplateParameterType(
1561                                                              NewDI->getType(),
1562                                                              D->getLocation());
1563        if (NewT.isNull())
1564          return 0;
1565        ExpandedParameterPackTypes.push_back(NewT);
1566      }
1567
1568      // Note that we have an expanded parameter pack. The "type" of this
1569      // expanded parameter pack is the original expansion type, but callers
1570      // will end up using the expanded parameter pack types for type-checking.
1571      IsExpandedParameterPack = true;
1572      DI = D->getTypeSourceInfo();
1573      T = DI->getType();
1574    } else {
1575      // We cannot fully expand the pack expansion now, so substitute into the
1576      // pattern and create a new pack expansion type.
1577      Sema::ArgumentPackSubstitutionIndexRAII SubstIndex(SemaRef, -1);
1578      TypeSourceInfo *NewPattern = SemaRef.SubstType(Pattern, TemplateArgs,
1579                                                     D->getLocation(),
1580                                                     D->getDeclName());
1581      if (!NewPattern)
1582        return 0;
1583
1584      DI = SemaRef.CheckPackExpansion(NewPattern, Expansion.getEllipsisLoc(),
1585                                      NumExpansions);
1586      if (!DI)
1587        return 0;
1588
1589      T = DI->getType();
1590    }
1591  } else {
1592    // Simple case: substitution into a parameter that is not a parameter pack.
1593    DI = SemaRef.SubstType(D->getTypeSourceInfo(), TemplateArgs,
1594                           D->getLocation(), D->getDeclName());
1595    if (!DI)
1596      return 0;
1597
1598    // Check that this type is acceptable for a non-type template parameter.
1599    bool Invalid = false;
1600    T = SemaRef.CheckNonTypeTemplateParameterType(DI->getType(),
1601                                                  D->getLocation());
1602    if (T.isNull()) {
1603      T = SemaRef.Context.IntTy;
1604      Invalid = true;
1605    }
1606  }
1607
1608  NonTypeTemplateParmDecl *Param;
1609  if (IsExpandedParameterPack)
1610    Param = NonTypeTemplateParmDecl::Create(SemaRef.Context, Owner,
1611                                            D->getInnerLocStart(),
1612                                            D->getLocation(),
1613                                    D->getDepth() - TemplateArgs.getNumLevels(),
1614                                            D->getPosition(),
1615                                            D->getIdentifier(), T,
1616                                            DI,
1617                                            ExpandedParameterPackTypes.data(),
1618                                            ExpandedParameterPackTypes.size(),
1619                                    ExpandedParameterPackTypesAsWritten.data());
1620  else
1621    Param = NonTypeTemplateParmDecl::Create(SemaRef.Context, Owner,
1622                                            D->getInnerLocStart(),
1623                                            D->getLocation(),
1624                                    D->getDepth() - TemplateArgs.getNumLevels(),
1625                                            D->getPosition(),
1626                                            D->getIdentifier(), T,
1627                                            D->isParameterPack(), DI);
1628
1629  Param->setAccess(AS_public);
1630  if (Invalid)
1631    Param->setInvalidDecl();
1632
1633  Param->setDefaultArgument(D->getDefaultArgument(), false);
1634
1635  // Introduce this template parameter's instantiation into the instantiation
1636  // scope.
1637  SemaRef.CurrentInstantiationScope->InstantiatedLocal(D, Param);
1638  return Param;
1639}
1640
1641Decl *
1642TemplateDeclInstantiator::VisitTemplateTemplateParmDecl(
1643                                                  TemplateTemplateParmDecl *D) {
1644  // Instantiate the template parameter list of the template template parameter.
1645  TemplateParameterList *TempParams = D->getTemplateParameters();
1646  TemplateParameterList *InstParams;
1647  {
1648    // Perform the actual substitution of template parameters within a new,
1649    // local instantiation scope.
1650    LocalInstantiationScope Scope(SemaRef);
1651    InstParams = SubstTemplateParams(TempParams);
1652    if (!InstParams)
1653      return NULL;
1654  }
1655
1656  // Build the template template parameter.
1657  TemplateTemplateParmDecl *Param
1658    = TemplateTemplateParmDecl::Create(SemaRef.Context, Owner, D->getLocation(),
1659                                   D->getDepth() - TemplateArgs.getNumLevels(),
1660                                       D->getPosition(), D->isParameterPack(),
1661                                       D->getIdentifier(), InstParams);
1662  Param->setDefaultArgument(D->getDefaultArgument(), false);
1663  Param->setAccess(AS_public);
1664
1665  // Introduce this template parameter's instantiation into the instantiation
1666  // scope.
1667  SemaRef.CurrentInstantiationScope->InstantiatedLocal(D, Param);
1668
1669  return Param;
1670}
1671
1672Decl *TemplateDeclInstantiator::VisitUsingDirectiveDecl(UsingDirectiveDecl *D) {
1673  // Using directives are never dependent (and never contain any types or
1674  // expressions), so they require no explicit instantiation work.
1675
1676  UsingDirectiveDecl *Inst
1677    = UsingDirectiveDecl::Create(SemaRef.Context, Owner, D->getLocation(),
1678                                 D->getNamespaceKeyLocation(),
1679                                 D->getQualifierLoc(),
1680                                 D->getIdentLocation(),
1681                                 D->getNominatedNamespace(),
1682                                 D->getCommonAncestor());
1683  Owner->addDecl(Inst);
1684  return Inst;
1685}
1686
1687Decl *TemplateDeclInstantiator::VisitUsingDecl(UsingDecl *D) {
1688
1689  // The nested name specifier may be dependent, for example
1690  //     template <typename T> struct t {
1691  //       struct s1 { T f1(); };
1692  //       struct s2 : s1 { using s1::f1; };
1693  //     };
1694  //     template struct t<int>;
1695  // Here, in using s1::f1, s1 refers to t<T>::s1;
1696  // we need to substitute for t<int>::s1.
1697  NestedNameSpecifierLoc QualifierLoc
1698    = SemaRef.SubstNestedNameSpecifierLoc(D->getQualifierLoc(),
1699                                          TemplateArgs);
1700  if (!QualifierLoc)
1701    return 0;
1702
1703  // The name info is non-dependent, so no transformation
1704  // is required.
1705  DeclarationNameInfo NameInfo = D->getNameInfo();
1706
1707  // We only need to do redeclaration lookups if we're in a class
1708  // scope (in fact, it's not really even possible in non-class
1709  // scopes).
1710  bool CheckRedeclaration = Owner->isRecord();
1711
1712  LookupResult Prev(SemaRef, NameInfo, Sema::LookupUsingDeclName,
1713                    Sema::ForRedeclaration);
1714
1715  UsingDecl *NewUD = UsingDecl::Create(SemaRef.Context, Owner,
1716                                       D->getUsingLocation(),
1717                                       QualifierLoc,
1718                                       NameInfo,
1719                                       D->isTypeName());
1720
1721  CXXScopeSpec SS;
1722  SS.Adopt(QualifierLoc);
1723  if (CheckRedeclaration) {
1724    Prev.setHideTags(false);
1725    SemaRef.LookupQualifiedName(Prev, Owner);
1726
1727    // Check for invalid redeclarations.
1728    if (SemaRef.CheckUsingDeclRedeclaration(D->getUsingLocation(),
1729                                            D->isTypeName(), SS,
1730                                            D->getLocation(), Prev))
1731      NewUD->setInvalidDecl();
1732
1733  }
1734
1735  if (!NewUD->isInvalidDecl() &&
1736      SemaRef.CheckUsingDeclQualifier(D->getUsingLocation(), SS,
1737                                      D->getLocation()))
1738    NewUD->setInvalidDecl();
1739
1740  SemaRef.Context.setInstantiatedFromUsingDecl(NewUD, D);
1741  NewUD->setAccess(D->getAccess());
1742  Owner->addDecl(NewUD);
1743
1744  // Don't process the shadow decls for an invalid decl.
1745  if (NewUD->isInvalidDecl())
1746    return NewUD;
1747
1748  bool isFunctionScope = Owner->isFunctionOrMethod();
1749
1750  // Process the shadow decls.
1751  for (UsingDecl::shadow_iterator I = D->shadow_begin(), E = D->shadow_end();
1752         I != E; ++I) {
1753    UsingShadowDecl *Shadow = *I;
1754    NamedDecl *InstTarget =
1755      cast_or_null<NamedDecl>(SemaRef.FindInstantiatedDecl(
1756                                                          Shadow->getLocation(),
1757                                                        Shadow->getTargetDecl(),
1758                                                           TemplateArgs));
1759    if (!InstTarget)
1760      return 0;
1761
1762    if (CheckRedeclaration &&
1763        SemaRef.CheckUsingShadowDecl(NewUD, InstTarget, Prev))
1764      continue;
1765
1766    UsingShadowDecl *InstShadow
1767      = SemaRef.BuildUsingShadowDecl(/*Scope*/ 0, NewUD, InstTarget);
1768    SemaRef.Context.setInstantiatedFromUsingShadowDecl(InstShadow, Shadow);
1769
1770    if (isFunctionScope)
1771      SemaRef.CurrentInstantiationScope->InstantiatedLocal(Shadow, InstShadow);
1772  }
1773
1774  return NewUD;
1775}
1776
1777Decl *TemplateDeclInstantiator::VisitUsingShadowDecl(UsingShadowDecl *D) {
1778  // Ignore these;  we handle them in bulk when processing the UsingDecl.
1779  return 0;
1780}
1781
1782Decl * TemplateDeclInstantiator
1783    ::VisitUnresolvedUsingTypenameDecl(UnresolvedUsingTypenameDecl *D) {
1784  NestedNameSpecifierLoc QualifierLoc
1785    = SemaRef.SubstNestedNameSpecifierLoc(D->getQualifierLoc(),
1786                                          TemplateArgs);
1787  if (!QualifierLoc)
1788    return 0;
1789
1790  CXXScopeSpec SS;
1791  SS.Adopt(QualifierLoc);
1792
1793  // Since NameInfo refers to a typename, it cannot be a C++ special name.
1794  // Hence, no tranformation is required for it.
1795  DeclarationNameInfo NameInfo(D->getDeclName(), D->getLocation());
1796  NamedDecl *UD =
1797    SemaRef.BuildUsingDeclaration(/*Scope*/ 0, D->getAccess(),
1798                                  D->getUsingLoc(), SS, NameInfo, 0,
1799                                  /*instantiation*/ true,
1800                                  /*typename*/ true, D->getTypenameLoc());
1801  if (UD)
1802    SemaRef.Context.setInstantiatedFromUsingDecl(cast<UsingDecl>(UD), D);
1803
1804  return UD;
1805}
1806
1807Decl * TemplateDeclInstantiator
1808    ::VisitUnresolvedUsingValueDecl(UnresolvedUsingValueDecl *D) {
1809  NestedNameSpecifierLoc QualifierLoc
1810      = SemaRef.SubstNestedNameSpecifierLoc(D->getQualifierLoc(), TemplateArgs);
1811  if (!QualifierLoc)
1812    return 0;
1813
1814  CXXScopeSpec SS;
1815  SS.Adopt(QualifierLoc);
1816
1817  DeclarationNameInfo NameInfo
1818    = SemaRef.SubstDeclarationNameInfo(D->getNameInfo(), TemplateArgs);
1819
1820  NamedDecl *UD =
1821    SemaRef.BuildUsingDeclaration(/*Scope*/ 0, D->getAccess(),
1822                                  D->getUsingLoc(), SS, NameInfo, 0,
1823                                  /*instantiation*/ true,
1824                                  /*typename*/ false, SourceLocation());
1825  if (UD)
1826    SemaRef.Context.setInstantiatedFromUsingDecl(cast<UsingDecl>(UD), D);
1827
1828  return UD;
1829}
1830
1831Decl *Sema::SubstDecl(Decl *D, DeclContext *Owner,
1832                      const MultiLevelTemplateArgumentList &TemplateArgs) {
1833  TemplateDeclInstantiator Instantiator(*this, Owner, TemplateArgs);
1834  if (D->isInvalidDecl())
1835    return 0;
1836
1837  return Instantiator.Visit(D);
1838}
1839
1840/// \brief Instantiates a nested template parameter list in the current
1841/// instantiation context.
1842///
1843/// \param L The parameter list to instantiate
1844///
1845/// \returns NULL if there was an error
1846TemplateParameterList *
1847TemplateDeclInstantiator::SubstTemplateParams(TemplateParameterList *L) {
1848  // Get errors for all the parameters before bailing out.
1849  bool Invalid = false;
1850
1851  unsigned N = L->size();
1852  typedef llvm::SmallVector<NamedDecl *, 8> ParamVector;
1853  ParamVector Params;
1854  Params.reserve(N);
1855  for (TemplateParameterList::iterator PI = L->begin(), PE = L->end();
1856       PI != PE; ++PI) {
1857    NamedDecl *D = cast_or_null<NamedDecl>(Visit(*PI));
1858    Params.push_back(D);
1859    Invalid = Invalid || !D || D->isInvalidDecl();
1860  }
1861
1862  // Clean up if we had an error.
1863  if (Invalid)
1864    return NULL;
1865
1866  TemplateParameterList *InstL
1867    = TemplateParameterList::Create(SemaRef.Context, L->getTemplateLoc(),
1868                                    L->getLAngleLoc(), &Params.front(), N,
1869                                    L->getRAngleLoc());
1870  return InstL;
1871}
1872
1873/// \brief Instantiate the declaration of a class template partial
1874/// specialization.
1875///
1876/// \param ClassTemplate the (instantiated) class template that is partially
1877// specialized by the instantiation of \p PartialSpec.
1878///
1879/// \param PartialSpec the (uninstantiated) class template partial
1880/// specialization that we are instantiating.
1881///
1882/// \returns The instantiated partial specialization, if successful; otherwise,
1883/// NULL to indicate an error.
1884ClassTemplatePartialSpecializationDecl *
1885TemplateDeclInstantiator::InstantiateClassTemplatePartialSpecialization(
1886                                            ClassTemplateDecl *ClassTemplate,
1887                          ClassTemplatePartialSpecializationDecl *PartialSpec) {
1888  // Create a local instantiation scope for this class template partial
1889  // specialization, which will contain the instantiations of the template
1890  // parameters.
1891  LocalInstantiationScope Scope(SemaRef);
1892
1893  // Substitute into the template parameters of the class template partial
1894  // specialization.
1895  TemplateParameterList *TempParams = PartialSpec->getTemplateParameters();
1896  TemplateParameterList *InstParams = SubstTemplateParams(TempParams);
1897  if (!InstParams)
1898    return 0;
1899
1900  // Substitute into the template arguments of the class template partial
1901  // specialization.
1902  TemplateArgumentListInfo InstTemplateArgs; // no angle locations
1903  if (SemaRef.Subst(PartialSpec->getTemplateArgsAsWritten(),
1904                    PartialSpec->getNumTemplateArgsAsWritten(),
1905                    InstTemplateArgs, TemplateArgs))
1906    return 0;
1907
1908  // Check that the template argument list is well-formed for this
1909  // class template.
1910  llvm::SmallVector<TemplateArgument, 4> Converted;
1911  if (SemaRef.CheckTemplateArgumentList(ClassTemplate,
1912                                        PartialSpec->getLocation(),
1913                                        InstTemplateArgs,
1914                                        false,
1915                                        Converted))
1916    return 0;
1917
1918  // Figure out where to insert this class template partial specialization
1919  // in the member template's set of class template partial specializations.
1920  void *InsertPos = 0;
1921  ClassTemplateSpecializationDecl *PrevDecl
1922    = ClassTemplate->findPartialSpecialization(Converted.data(),
1923                                               Converted.size(), InsertPos);
1924
1925  // Build the canonical type that describes the converted template
1926  // arguments of the class template partial specialization.
1927  QualType CanonType
1928    = SemaRef.Context.getTemplateSpecializationType(TemplateName(ClassTemplate),
1929                                                    Converted.data(),
1930                                                    Converted.size());
1931
1932  // Build the fully-sugared type for this class template
1933  // specialization as the user wrote in the specialization
1934  // itself. This means that we'll pretty-print the type retrieved
1935  // from the specialization's declaration the way that the user
1936  // actually wrote the specialization, rather than formatting the
1937  // name based on the "canonical" representation used to store the
1938  // template arguments in the specialization.
1939  TypeSourceInfo *WrittenTy
1940    = SemaRef.Context.getTemplateSpecializationTypeInfo(
1941                                                    TemplateName(ClassTemplate),
1942                                                    PartialSpec->getLocation(),
1943                                                    InstTemplateArgs,
1944                                                    CanonType);
1945
1946  if (PrevDecl) {
1947    // We've already seen a partial specialization with the same template
1948    // parameters and template arguments. This can happen, for example, when
1949    // substituting the outer template arguments ends up causing two
1950    // class template partial specializations of a member class template
1951    // to have identical forms, e.g.,
1952    //
1953    //   template<typename T, typename U>
1954    //   struct Outer {
1955    //     template<typename X, typename Y> struct Inner;
1956    //     template<typename Y> struct Inner<T, Y>;
1957    //     template<typename Y> struct Inner<U, Y>;
1958    //   };
1959    //
1960    //   Outer<int, int> outer; // error: the partial specializations of Inner
1961    //                          // have the same signature.
1962    SemaRef.Diag(PartialSpec->getLocation(), diag::err_partial_spec_redeclared)
1963      << WrittenTy->getType();
1964    SemaRef.Diag(PrevDecl->getLocation(), diag::note_prev_partial_spec_here)
1965      << SemaRef.Context.getTypeDeclType(PrevDecl);
1966    return 0;
1967  }
1968
1969
1970  // Create the class template partial specialization declaration.
1971  ClassTemplatePartialSpecializationDecl *InstPartialSpec
1972    = ClassTemplatePartialSpecializationDecl::Create(SemaRef.Context,
1973                                                     PartialSpec->getTagKind(),
1974                                                     Owner,
1975                                                     PartialSpec->getLocStart(),
1976                                                     PartialSpec->getLocation(),
1977                                                     InstParams,
1978                                                     ClassTemplate,
1979                                                     Converted.data(),
1980                                                     Converted.size(),
1981                                                     InstTemplateArgs,
1982                                                     CanonType,
1983                                                     0,
1984                             ClassTemplate->getNextPartialSpecSequenceNumber());
1985  // Substitute the nested name specifier, if any.
1986  if (SubstQualifier(PartialSpec, InstPartialSpec))
1987    return 0;
1988
1989  InstPartialSpec->setInstantiatedFromMember(PartialSpec);
1990  InstPartialSpec->setTypeAsWritten(WrittenTy);
1991
1992  // Add this partial specialization to the set of class template partial
1993  // specializations.
1994  ClassTemplate->AddPartialSpecialization(InstPartialSpec, InsertPos);
1995  return InstPartialSpec;
1996}
1997
1998TypeSourceInfo*
1999TemplateDeclInstantiator::SubstFunctionType(FunctionDecl *D,
2000                              llvm::SmallVectorImpl<ParmVarDecl *> &Params) {
2001  TypeSourceInfo *OldTInfo = D->getTypeSourceInfo();
2002  assert(OldTInfo && "substituting function without type source info");
2003  assert(Params.empty() && "parameter vector is non-empty at start");
2004  TypeSourceInfo *NewTInfo
2005    = SemaRef.SubstFunctionDeclType(OldTInfo, TemplateArgs,
2006                                    D->getTypeSpecStartLoc(),
2007                                    D->getDeclName());
2008  if (!NewTInfo)
2009    return 0;
2010
2011  if (NewTInfo != OldTInfo) {
2012    // Get parameters from the new type info.
2013    TypeLoc OldTL = OldTInfo->getTypeLoc().IgnoreParens();
2014    if (FunctionProtoTypeLoc *OldProtoLoc
2015                                  = dyn_cast<FunctionProtoTypeLoc>(&OldTL)) {
2016      TypeLoc NewTL = NewTInfo->getTypeLoc().IgnoreParens();
2017      FunctionProtoTypeLoc *NewProtoLoc = cast<FunctionProtoTypeLoc>(&NewTL);
2018      assert(NewProtoLoc && "Missing prototype?");
2019      unsigned NewIdx = 0, NumNewParams = NewProtoLoc->getNumArgs();
2020      for (unsigned OldIdx = 0, NumOldParams = OldProtoLoc->getNumArgs();
2021           OldIdx != NumOldParams; ++OldIdx) {
2022        ParmVarDecl *OldParam = OldProtoLoc->getArg(OldIdx);
2023        if (!OldParam->isParameterPack() ||
2024            (NewIdx < NumNewParams &&
2025             NewProtoLoc->getArg(NewIdx)->isParameterPack())) {
2026          // Simple case: normal parameter, or a parameter pack that's
2027          // instantiated to a (still-dependent) parameter pack.
2028          ParmVarDecl *NewParam = NewProtoLoc->getArg(NewIdx++);
2029          Params.push_back(NewParam);
2030          SemaRef.CurrentInstantiationScope->InstantiatedLocal(OldParam,
2031                                                               NewParam);
2032          continue;
2033        }
2034
2035        // Parameter pack: make the instantiation an argument pack.
2036        SemaRef.CurrentInstantiationScope->MakeInstantiatedLocalArgPack(
2037                                                                      OldParam);
2038        unsigned NumArgumentsInExpansion
2039          = SemaRef.getNumArgumentsInExpansion(OldParam->getType(),
2040                                               TemplateArgs);
2041        while (NumArgumentsInExpansion--) {
2042          ParmVarDecl *NewParam = NewProtoLoc->getArg(NewIdx++);
2043          Params.push_back(NewParam);
2044          SemaRef.CurrentInstantiationScope->InstantiatedLocalPackArg(OldParam,
2045                                                                      NewParam);
2046        }
2047      }
2048    }
2049  } else {
2050    // The function type itself was not dependent and therefore no
2051    // substitution occurred. However, we still need to instantiate
2052    // the function parameters themselves.
2053    TypeLoc OldTL = OldTInfo->getTypeLoc().IgnoreParens();
2054    if (FunctionProtoTypeLoc *OldProtoLoc
2055                                    = dyn_cast<FunctionProtoTypeLoc>(&OldTL)) {
2056      for (unsigned i = 0, i_end = OldProtoLoc->getNumArgs(); i != i_end; ++i) {
2057        ParmVarDecl *Parm = VisitParmVarDecl(OldProtoLoc->getArg(i));
2058        if (!Parm)
2059          return 0;
2060        Params.push_back(Parm);
2061      }
2062    }
2063  }
2064  return NewTInfo;
2065}
2066
2067/// \brief Initializes the common fields of an instantiation function
2068/// declaration (New) from the corresponding fields of its template (Tmpl).
2069///
2070/// \returns true if there was an error
2071bool
2072TemplateDeclInstantiator::InitFunctionInstantiation(FunctionDecl *New,
2073                                                    FunctionDecl *Tmpl) {
2074  if (Tmpl->isDeleted())
2075    New->setDeleted();
2076
2077  // If we are performing substituting explicitly-specified template arguments
2078  // or deduced template arguments into a function template and we reach this
2079  // point, we are now past the point where SFINAE applies and have committed
2080  // to keeping the new function template specialization. We therefore
2081  // convert the active template instantiation for the function template
2082  // into a template instantiation for this specific function template
2083  // specialization, which is not a SFINAE context, so that we diagnose any
2084  // further errors in the declaration itself.
2085  typedef Sema::ActiveTemplateInstantiation ActiveInstType;
2086  ActiveInstType &ActiveInst = SemaRef.ActiveTemplateInstantiations.back();
2087  if (ActiveInst.Kind == ActiveInstType::ExplicitTemplateArgumentSubstitution ||
2088      ActiveInst.Kind == ActiveInstType::DeducedTemplateArgumentSubstitution) {
2089    if (FunctionTemplateDecl *FunTmpl
2090          = dyn_cast<FunctionTemplateDecl>((Decl *)ActiveInst.Entity)) {
2091      assert(FunTmpl->getTemplatedDecl() == Tmpl &&
2092             "Deduction from the wrong function template?");
2093      (void) FunTmpl;
2094      ActiveInst.Kind = ActiveInstType::TemplateInstantiation;
2095      ActiveInst.Entity = reinterpret_cast<uintptr_t>(New);
2096      --SemaRef.NonInstantiationEntries;
2097    }
2098  }
2099
2100  const FunctionProtoType *Proto = Tmpl->getType()->getAs<FunctionProtoType>();
2101  assert(Proto && "Function template without prototype?");
2102
2103  if (Proto->hasExceptionSpec() || Proto->getNoReturnAttr()) {
2104    // The function has an exception specification or a "noreturn"
2105    // attribute. Substitute into each of the exception types.
2106    llvm::SmallVector<QualType, 4> Exceptions;
2107    for (unsigned I = 0, N = Proto->getNumExceptions(); I != N; ++I) {
2108      // FIXME: Poor location information!
2109      if (const PackExpansionType *PackExpansion
2110            = Proto->getExceptionType(I)->getAs<PackExpansionType>()) {
2111        // We have a pack expansion. Instantiate it.
2112        llvm::SmallVector<UnexpandedParameterPack, 2> Unexpanded;
2113        SemaRef.collectUnexpandedParameterPacks(PackExpansion->getPattern(),
2114                                                Unexpanded);
2115        assert(!Unexpanded.empty() &&
2116               "Pack expansion without parameter packs?");
2117
2118        bool Expand = false;
2119        bool RetainExpansion = false;
2120        llvm::Optional<unsigned> NumExpansions
2121                                          = PackExpansion->getNumExpansions();
2122        if (SemaRef.CheckParameterPacksForExpansion(New->getLocation(),
2123                                                    SourceRange(),
2124                                                    Unexpanded.data(),
2125                                                    Unexpanded.size(),
2126                                                    TemplateArgs,
2127                                                    Expand,
2128                                                    RetainExpansion,
2129                                                    NumExpansions))
2130          break;
2131
2132        if (!Expand) {
2133          // We can't expand this pack expansion into separate arguments yet;
2134          // just substitute into the pattern and create a new pack expansion
2135          // type.
2136          Sema::ArgumentPackSubstitutionIndexRAII SubstIndex(SemaRef, -1);
2137          QualType T = SemaRef.SubstType(PackExpansion->getPattern(),
2138                                         TemplateArgs,
2139                                       New->getLocation(), New->getDeclName());
2140          if (T.isNull())
2141            break;
2142
2143          T = SemaRef.Context.getPackExpansionType(T, NumExpansions);
2144          Exceptions.push_back(T);
2145          continue;
2146        }
2147
2148        // Substitute into the pack expansion pattern for each template
2149        bool Invalid = false;
2150        for (unsigned ArgIdx = 0; ArgIdx != *NumExpansions; ++ArgIdx) {
2151          Sema::ArgumentPackSubstitutionIndexRAII SubstIndex(SemaRef, ArgIdx);
2152
2153          QualType T = SemaRef.SubstType(PackExpansion->getPattern(),
2154                                         TemplateArgs,
2155                                       New->getLocation(), New->getDeclName());
2156          if (T.isNull()) {
2157            Invalid = true;
2158            break;
2159          }
2160
2161          Exceptions.push_back(T);
2162        }
2163
2164        if (Invalid)
2165          break;
2166
2167        continue;
2168      }
2169
2170      QualType T
2171        = SemaRef.SubstType(Proto->getExceptionType(I), TemplateArgs,
2172                            New->getLocation(), New->getDeclName());
2173      if (T.isNull() ||
2174          SemaRef.CheckSpecifiedExceptionType(T, New->getLocation()))
2175        continue;
2176
2177      Exceptions.push_back(T);
2178    }
2179    Expr *NoexceptExpr = 0;
2180    if (Expr *OldNoexceptExpr = Proto->getNoexceptExpr()) {
2181      ExprResult E = SemaRef.SubstExpr(OldNoexceptExpr, TemplateArgs);
2182      if (E.isUsable())
2183        NoexceptExpr = E.take();
2184    }
2185
2186    // Rebuild the function type
2187
2188    FunctionProtoType::ExtProtoInfo EPI = Proto->getExtProtoInfo();
2189    EPI.ExceptionSpecType = Proto->getExceptionSpecType();
2190    EPI.NumExceptions = Exceptions.size();
2191    EPI.Exceptions = Exceptions.data();
2192    EPI.NoexceptExpr = NoexceptExpr;
2193    EPI.ExtInfo = Proto->getExtInfo();
2194
2195    const FunctionProtoType *NewProto
2196      = New->getType()->getAs<FunctionProtoType>();
2197    assert(NewProto && "Template instantiation without function prototype?");
2198    New->setType(SemaRef.Context.getFunctionType(NewProto->getResultType(),
2199                                                 NewProto->arg_type_begin(),
2200                                                 NewProto->getNumArgs(),
2201                                                 EPI));
2202  }
2203
2204  SemaRef.InstantiateAttrs(TemplateArgs, Tmpl, New);
2205
2206  return false;
2207}
2208
2209/// \brief Initializes common fields of an instantiated method
2210/// declaration (New) from the corresponding fields of its template
2211/// (Tmpl).
2212///
2213/// \returns true if there was an error
2214bool
2215TemplateDeclInstantiator::InitMethodInstantiation(CXXMethodDecl *New,
2216                                                  CXXMethodDecl *Tmpl) {
2217  if (InitFunctionInstantiation(New, Tmpl))
2218    return true;
2219
2220  New->setAccess(Tmpl->getAccess());
2221  if (Tmpl->isVirtualAsWritten())
2222    New->setVirtualAsWritten(true);
2223
2224  // FIXME: attributes
2225  // FIXME: New needs a pointer to Tmpl
2226  return false;
2227}
2228
2229/// \brief Instantiate the definition of the given function from its
2230/// template.
2231///
2232/// \param PointOfInstantiation the point at which the instantiation was
2233/// required. Note that this is not precisely a "point of instantiation"
2234/// for the function, but it's close.
2235///
2236/// \param Function the already-instantiated declaration of a
2237/// function template specialization or member function of a class template
2238/// specialization.
2239///
2240/// \param Recursive if true, recursively instantiates any functions that
2241/// are required by this instantiation.
2242///
2243/// \param DefinitionRequired if true, then we are performing an explicit
2244/// instantiation where the body of the function is required. Complain if
2245/// there is no such body.
2246void Sema::InstantiateFunctionDefinition(SourceLocation PointOfInstantiation,
2247                                         FunctionDecl *Function,
2248                                         bool Recursive,
2249                                         bool DefinitionRequired) {
2250  if (Function->isInvalidDecl() || Function->hasBody())
2251    return;
2252
2253  // Never instantiate an explicit specialization.
2254  if (Function->getTemplateSpecializationKind() == TSK_ExplicitSpecialization)
2255    return;
2256
2257  // Find the function body that we'll be substituting.
2258  const FunctionDecl *PatternDecl = Function->getTemplateInstantiationPattern();
2259  Stmt *Pattern = 0;
2260  if (PatternDecl)
2261    Pattern = PatternDecl->getBody(PatternDecl);
2262
2263  if (!Pattern) {
2264    if (DefinitionRequired) {
2265      if (Function->getPrimaryTemplate())
2266        Diag(PointOfInstantiation,
2267             diag::err_explicit_instantiation_undefined_func_template)
2268          << Function->getPrimaryTemplate();
2269      else
2270        Diag(PointOfInstantiation,
2271             diag::err_explicit_instantiation_undefined_member)
2272          << 1 << Function->getDeclName() << Function->getDeclContext();
2273
2274      if (PatternDecl)
2275        Diag(PatternDecl->getLocation(),
2276             diag::note_explicit_instantiation_here);
2277      Function->setInvalidDecl();
2278    } else if (Function->getTemplateSpecializationKind()
2279                 == TSK_ExplicitInstantiationDefinition) {
2280      PendingInstantiations.push_back(
2281        std::make_pair(Function, PointOfInstantiation));
2282    }
2283
2284    return;
2285  }
2286
2287  // C++0x [temp.explicit]p9:
2288  //   Except for inline functions, other explicit instantiation declarations
2289  //   have the effect of suppressing the implicit instantiation of the entity
2290  //   to which they refer.
2291  if (Function->getTemplateSpecializationKind()
2292        == TSK_ExplicitInstantiationDeclaration &&
2293      !PatternDecl->isInlined())
2294    return;
2295
2296  InstantiatingTemplate Inst(*this, PointOfInstantiation, Function);
2297  if (Inst)
2298    return;
2299
2300  // If we're performing recursive template instantiation, create our own
2301  // queue of pending implicit instantiations that we will instantiate later,
2302  // while we're still within our own instantiation context.
2303  llvm::SmallVector<VTableUse, 16> SavedVTableUses;
2304  std::deque<PendingImplicitInstantiation> SavedPendingInstantiations;
2305  if (Recursive) {
2306    VTableUses.swap(SavedVTableUses);
2307    PendingInstantiations.swap(SavedPendingInstantiations);
2308  }
2309
2310  EnterExpressionEvaluationContext EvalContext(*this,
2311                                               Sema::PotentiallyEvaluated);
2312  ActOnStartOfFunctionDef(0, Function);
2313
2314  // Introduce a new scope where local variable instantiations will be
2315  // recorded, unless we're actually a member function within a local
2316  // class, in which case we need to merge our results with the parent
2317  // scope (of the enclosing function).
2318  bool MergeWithParentScope = false;
2319  if (CXXRecordDecl *Rec = dyn_cast<CXXRecordDecl>(Function->getDeclContext()))
2320    MergeWithParentScope = Rec->isLocalClass();
2321
2322  LocalInstantiationScope Scope(*this, MergeWithParentScope);
2323
2324  // Introduce the instantiated function parameters into the local
2325  // instantiation scope, and set the parameter names to those used
2326  // in the template.
2327  unsigned FParamIdx = 0;
2328  for (unsigned I = 0, N = PatternDecl->getNumParams(); I != N; ++I) {
2329    const ParmVarDecl *PatternParam = PatternDecl->getParamDecl(I);
2330    if (!PatternParam->isParameterPack()) {
2331      // Simple case: not a parameter pack.
2332      assert(FParamIdx < Function->getNumParams());
2333      ParmVarDecl *FunctionParam = Function->getParamDecl(I);
2334      FunctionParam->setDeclName(PatternParam->getDeclName());
2335      Scope.InstantiatedLocal(PatternParam, FunctionParam);
2336      ++FParamIdx;
2337      continue;
2338    }
2339
2340    // Expand the parameter pack.
2341    Scope.MakeInstantiatedLocalArgPack(PatternParam);
2342    for (unsigned NumFParams = Function->getNumParams();
2343         FParamIdx < NumFParams;
2344         ++FParamIdx) {
2345      ParmVarDecl *FunctionParam = Function->getParamDecl(FParamIdx);
2346      FunctionParam->setDeclName(PatternParam->getDeclName());
2347      Scope.InstantiatedLocalPackArg(PatternParam, FunctionParam);
2348    }
2349  }
2350
2351  // Enter the scope of this instantiation. We don't use
2352  // PushDeclContext because we don't have a scope.
2353  Sema::ContextRAII savedContext(*this, Function);
2354
2355  MultiLevelTemplateArgumentList TemplateArgs =
2356    getTemplateInstantiationArgs(Function, 0, false, PatternDecl);
2357
2358  // If this is a constructor, instantiate the member initializers.
2359  if (const CXXConstructorDecl *Ctor =
2360        dyn_cast<CXXConstructorDecl>(PatternDecl)) {
2361    InstantiateMemInitializers(cast<CXXConstructorDecl>(Function), Ctor,
2362                               TemplateArgs);
2363  }
2364
2365  // Instantiate the function body.
2366  StmtResult Body = SubstStmt(Pattern, TemplateArgs);
2367
2368  if (Body.isInvalid())
2369    Function->setInvalidDecl();
2370
2371  ActOnFinishFunctionBody(Function, Body.get(),
2372                          /*IsInstantiation=*/true);
2373
2374  PerformDependentDiagnostics(PatternDecl, TemplateArgs);
2375
2376  savedContext.pop();
2377
2378  DeclGroupRef DG(Function);
2379  Consumer.HandleTopLevelDecl(DG);
2380
2381  // This class may have local implicit instantiations that need to be
2382  // instantiation within this scope.
2383  PerformPendingInstantiations(/*LocalOnly=*/true);
2384  Scope.Exit();
2385
2386  if (Recursive) {
2387    // Define any pending vtables.
2388    DefineUsedVTables();
2389
2390    // Instantiate any pending implicit instantiations found during the
2391    // instantiation of this template.
2392    PerformPendingInstantiations();
2393
2394    // Restore the set of pending vtables.
2395    VTableUses.swap(SavedVTableUses);
2396
2397    // Restore the set of pending implicit instantiations.
2398    PendingInstantiations.swap(SavedPendingInstantiations);
2399  }
2400}
2401
2402/// \brief Instantiate the definition of the given variable from its
2403/// template.
2404///
2405/// \param PointOfInstantiation the point at which the instantiation was
2406/// required. Note that this is not precisely a "point of instantiation"
2407/// for the function, but it's close.
2408///
2409/// \param Var the already-instantiated declaration of a static member
2410/// variable of a class template specialization.
2411///
2412/// \param Recursive if true, recursively instantiates any functions that
2413/// are required by this instantiation.
2414///
2415/// \param DefinitionRequired if true, then we are performing an explicit
2416/// instantiation where an out-of-line definition of the member variable
2417/// is required. Complain if there is no such definition.
2418void Sema::InstantiateStaticDataMemberDefinition(
2419                                          SourceLocation PointOfInstantiation,
2420                                                 VarDecl *Var,
2421                                                 bool Recursive,
2422                                                 bool DefinitionRequired) {
2423  if (Var->isInvalidDecl())
2424    return;
2425
2426  // Find the out-of-line definition of this static data member.
2427  VarDecl *Def = Var->getInstantiatedFromStaticDataMember();
2428  assert(Def && "This data member was not instantiated from a template?");
2429  assert(Def->isStaticDataMember() && "Not a static data member?");
2430  Def = Def->getOutOfLineDefinition();
2431
2432  if (!Def) {
2433    // We did not find an out-of-line definition of this static data member,
2434    // so we won't perform any instantiation. Rather, we rely on the user to
2435    // instantiate this definition (or provide a specialization for it) in
2436    // another translation unit.
2437    if (DefinitionRequired) {
2438      Def = Var->getInstantiatedFromStaticDataMember();
2439      Diag(PointOfInstantiation,
2440           diag::err_explicit_instantiation_undefined_member)
2441        << 2 << Var->getDeclName() << Var->getDeclContext();
2442      Diag(Def->getLocation(), diag::note_explicit_instantiation_here);
2443    } else if (Var->getTemplateSpecializationKind()
2444                 == TSK_ExplicitInstantiationDefinition) {
2445      PendingInstantiations.push_back(
2446        std::make_pair(Var, PointOfInstantiation));
2447    }
2448
2449    return;
2450  }
2451
2452  // Never instantiate an explicit specialization.
2453  if (Var->getTemplateSpecializationKind() == TSK_ExplicitSpecialization)
2454    return;
2455
2456  // C++0x [temp.explicit]p9:
2457  //   Except for inline functions, other explicit instantiation declarations
2458  //   have the effect of suppressing the implicit instantiation of the entity
2459  //   to which they refer.
2460  if (Var->getTemplateSpecializationKind()
2461        == TSK_ExplicitInstantiationDeclaration)
2462    return;
2463
2464  InstantiatingTemplate Inst(*this, PointOfInstantiation, Var);
2465  if (Inst)
2466    return;
2467
2468  // If we're performing recursive template instantiation, create our own
2469  // queue of pending implicit instantiations that we will instantiate later,
2470  // while we're still within our own instantiation context.
2471  std::deque<PendingImplicitInstantiation> SavedPendingInstantiations;
2472  if (Recursive)
2473    PendingInstantiations.swap(SavedPendingInstantiations);
2474
2475  // Enter the scope of this instantiation. We don't use
2476  // PushDeclContext because we don't have a scope.
2477  ContextRAII previousContext(*this, Var->getDeclContext());
2478
2479  VarDecl *OldVar = Var;
2480  Var = cast_or_null<VarDecl>(SubstDecl(Def, Var->getDeclContext(),
2481                                        getTemplateInstantiationArgs(Var)));
2482
2483  previousContext.pop();
2484
2485  if (Var) {
2486    MemberSpecializationInfo *MSInfo = OldVar->getMemberSpecializationInfo();
2487    assert(MSInfo && "Missing member specialization information?");
2488    Var->setTemplateSpecializationKind(MSInfo->getTemplateSpecializationKind(),
2489                                       MSInfo->getPointOfInstantiation());
2490    DeclGroupRef DG(Var);
2491    Consumer.HandleTopLevelDecl(DG);
2492  }
2493
2494  if (Recursive) {
2495    // Instantiate any pending implicit instantiations found during the
2496    // instantiation of this template.
2497    PerformPendingInstantiations();
2498
2499    // Restore the set of pending implicit instantiations.
2500    PendingInstantiations.swap(SavedPendingInstantiations);
2501  }
2502}
2503
2504void
2505Sema::InstantiateMemInitializers(CXXConstructorDecl *New,
2506                                 const CXXConstructorDecl *Tmpl,
2507                           const MultiLevelTemplateArgumentList &TemplateArgs) {
2508
2509  llvm::SmallVector<MemInitTy*, 4> NewInits;
2510  bool AnyErrors = false;
2511
2512  // Instantiate all the initializers.
2513  for (CXXConstructorDecl::init_const_iterator Inits = Tmpl->init_begin(),
2514                                            InitsEnd = Tmpl->init_end();
2515       Inits != InitsEnd; ++Inits) {
2516    CXXCtorInitializer *Init = *Inits;
2517
2518    // Only instantiate written initializers, let Sema re-construct implicit
2519    // ones.
2520    if (!Init->isWritten())
2521      continue;
2522
2523    SourceLocation LParenLoc, RParenLoc;
2524    ASTOwningVector<Expr*> NewArgs(*this);
2525
2526    SourceLocation EllipsisLoc;
2527
2528    if (Init->isPackExpansion()) {
2529      // This is a pack expansion. We should expand it now.
2530      TypeLoc BaseTL = Init->getBaseClassInfo()->getTypeLoc();
2531      llvm::SmallVector<UnexpandedParameterPack, 2> Unexpanded;
2532      collectUnexpandedParameterPacks(BaseTL, Unexpanded);
2533      bool ShouldExpand = false;
2534      bool RetainExpansion = false;
2535      llvm::Optional<unsigned> NumExpansions;
2536      if (CheckParameterPacksForExpansion(Init->getEllipsisLoc(),
2537                                          BaseTL.getSourceRange(),
2538                                          Unexpanded.data(),
2539                                          Unexpanded.size(),
2540                                          TemplateArgs, ShouldExpand,
2541                                          RetainExpansion,
2542                                          NumExpansions)) {
2543        AnyErrors = true;
2544        New->setInvalidDecl();
2545        continue;
2546      }
2547      assert(ShouldExpand && "Partial instantiation of base initializer?");
2548
2549      // Loop over all of the arguments in the argument pack(s),
2550      for (unsigned I = 0; I != *NumExpansions; ++I) {
2551        Sema::ArgumentPackSubstitutionIndexRAII SubstIndex(*this, I);
2552
2553        // Instantiate the initializer.
2554        if (InstantiateInitializer(*this, Init->getInit(), TemplateArgs,
2555                                   LParenLoc, NewArgs, RParenLoc)) {
2556          AnyErrors = true;
2557          break;
2558        }
2559
2560        // Instantiate the base type.
2561        TypeSourceInfo *BaseTInfo = SubstType(Init->getBaseClassInfo(),
2562                                              TemplateArgs,
2563                                              Init->getSourceLocation(),
2564                                              New->getDeclName());
2565        if (!BaseTInfo) {
2566          AnyErrors = true;
2567          break;
2568        }
2569
2570        // Build the initializer.
2571        MemInitResult NewInit = BuildBaseInitializer(BaseTInfo->getType(),
2572                                                     BaseTInfo,
2573                                                     (Expr **)NewArgs.data(),
2574                                                     NewArgs.size(),
2575                                                     Init->getLParenLoc(),
2576                                                     Init->getRParenLoc(),
2577                                                     New->getParent(),
2578                                                     SourceLocation());
2579        if (NewInit.isInvalid()) {
2580          AnyErrors = true;
2581          break;
2582        }
2583
2584        NewInits.push_back(NewInit.get());
2585        NewArgs.clear();
2586      }
2587
2588      continue;
2589    }
2590
2591    // Instantiate the initializer.
2592    if (InstantiateInitializer(*this, Init->getInit(), TemplateArgs,
2593                               LParenLoc, NewArgs, RParenLoc)) {
2594      AnyErrors = true;
2595      continue;
2596    }
2597
2598    MemInitResult NewInit;
2599    if (Init->isBaseInitializer()) {
2600      TypeSourceInfo *BaseTInfo = SubstType(Init->getBaseClassInfo(),
2601                                            TemplateArgs,
2602                                            Init->getSourceLocation(),
2603                                            New->getDeclName());
2604      if (!BaseTInfo) {
2605        AnyErrors = true;
2606        New->setInvalidDecl();
2607        continue;
2608      }
2609
2610      NewInit = BuildBaseInitializer(BaseTInfo->getType(), BaseTInfo,
2611                                     (Expr **)NewArgs.data(),
2612                                     NewArgs.size(),
2613                                     Init->getLParenLoc(),
2614                                     Init->getRParenLoc(),
2615                                     New->getParent(),
2616                                     EllipsisLoc);
2617    } else if (Init->isMemberInitializer()) {
2618      FieldDecl *Member = cast_or_null<FieldDecl>(FindInstantiatedDecl(
2619                                                     Init->getMemberLocation(),
2620                                                     Init->getMember(),
2621                                                     TemplateArgs));
2622      if (!Member) {
2623        AnyErrors = true;
2624        New->setInvalidDecl();
2625        continue;
2626      }
2627
2628      NewInit = BuildMemberInitializer(Member, (Expr **)NewArgs.data(),
2629                                       NewArgs.size(),
2630                                       Init->getSourceLocation(),
2631                                       Init->getLParenLoc(),
2632                                       Init->getRParenLoc());
2633    } else if (Init->isIndirectMemberInitializer()) {
2634      IndirectFieldDecl *IndirectMember =
2635         cast_or_null<IndirectFieldDecl>(FindInstantiatedDecl(
2636                                 Init->getMemberLocation(),
2637                                 Init->getIndirectMember(), TemplateArgs));
2638
2639      if (!IndirectMember) {
2640        AnyErrors = true;
2641        New->setInvalidDecl();
2642        continue;
2643      }
2644
2645      NewInit = BuildMemberInitializer(IndirectMember, (Expr **)NewArgs.data(),
2646                                       NewArgs.size(),
2647                                       Init->getSourceLocation(),
2648                                       Init->getLParenLoc(),
2649                                       Init->getRParenLoc());
2650    }
2651
2652    if (NewInit.isInvalid()) {
2653      AnyErrors = true;
2654      New->setInvalidDecl();
2655    } else {
2656      // FIXME: It would be nice if ASTOwningVector had a release function.
2657      NewArgs.take();
2658
2659      NewInits.push_back((MemInitTy *)NewInit.get());
2660    }
2661  }
2662
2663  // Assign all the initializers to the new constructor.
2664  ActOnMemInitializers(New,
2665                       /*FIXME: ColonLoc */
2666                       SourceLocation(),
2667                       NewInits.data(), NewInits.size(),
2668                       AnyErrors);
2669}
2670
2671// TODO: this could be templated if the various decl types used the
2672// same method name.
2673static bool isInstantiationOf(ClassTemplateDecl *Pattern,
2674                              ClassTemplateDecl *Instance) {
2675  Pattern = Pattern->getCanonicalDecl();
2676
2677  do {
2678    Instance = Instance->getCanonicalDecl();
2679    if (Pattern == Instance) return true;
2680    Instance = Instance->getInstantiatedFromMemberTemplate();
2681  } while (Instance);
2682
2683  return false;
2684}
2685
2686static bool isInstantiationOf(FunctionTemplateDecl *Pattern,
2687                              FunctionTemplateDecl *Instance) {
2688  Pattern = Pattern->getCanonicalDecl();
2689
2690  do {
2691    Instance = Instance->getCanonicalDecl();
2692    if (Pattern == Instance) return true;
2693    Instance = Instance->getInstantiatedFromMemberTemplate();
2694  } while (Instance);
2695
2696  return false;
2697}
2698
2699static bool
2700isInstantiationOf(ClassTemplatePartialSpecializationDecl *Pattern,
2701                  ClassTemplatePartialSpecializationDecl *Instance) {
2702  Pattern
2703    = cast<ClassTemplatePartialSpecializationDecl>(Pattern->getCanonicalDecl());
2704  do {
2705    Instance = cast<ClassTemplatePartialSpecializationDecl>(
2706                                                Instance->getCanonicalDecl());
2707    if (Pattern == Instance)
2708      return true;
2709    Instance = Instance->getInstantiatedFromMember();
2710  } while (Instance);
2711
2712  return false;
2713}
2714
2715static bool isInstantiationOf(CXXRecordDecl *Pattern,
2716                              CXXRecordDecl *Instance) {
2717  Pattern = Pattern->getCanonicalDecl();
2718
2719  do {
2720    Instance = Instance->getCanonicalDecl();
2721    if (Pattern == Instance) return true;
2722    Instance = Instance->getInstantiatedFromMemberClass();
2723  } while (Instance);
2724
2725  return false;
2726}
2727
2728static bool isInstantiationOf(FunctionDecl *Pattern,
2729                              FunctionDecl *Instance) {
2730  Pattern = Pattern->getCanonicalDecl();
2731
2732  do {
2733    Instance = Instance->getCanonicalDecl();
2734    if (Pattern == Instance) return true;
2735    Instance = Instance->getInstantiatedFromMemberFunction();
2736  } while (Instance);
2737
2738  return false;
2739}
2740
2741static bool isInstantiationOf(EnumDecl *Pattern,
2742                              EnumDecl *Instance) {
2743  Pattern = Pattern->getCanonicalDecl();
2744
2745  do {
2746    Instance = Instance->getCanonicalDecl();
2747    if (Pattern == Instance) return true;
2748    Instance = Instance->getInstantiatedFromMemberEnum();
2749  } while (Instance);
2750
2751  return false;
2752}
2753
2754static bool isInstantiationOf(UsingShadowDecl *Pattern,
2755                              UsingShadowDecl *Instance,
2756                              ASTContext &C) {
2757  return C.getInstantiatedFromUsingShadowDecl(Instance) == Pattern;
2758}
2759
2760static bool isInstantiationOf(UsingDecl *Pattern,
2761                              UsingDecl *Instance,
2762                              ASTContext &C) {
2763  return C.getInstantiatedFromUsingDecl(Instance) == Pattern;
2764}
2765
2766static bool isInstantiationOf(UnresolvedUsingValueDecl *Pattern,
2767                              UsingDecl *Instance,
2768                              ASTContext &C) {
2769  return C.getInstantiatedFromUsingDecl(Instance) == Pattern;
2770}
2771
2772static bool isInstantiationOf(UnresolvedUsingTypenameDecl *Pattern,
2773                              UsingDecl *Instance,
2774                              ASTContext &C) {
2775  return C.getInstantiatedFromUsingDecl(Instance) == Pattern;
2776}
2777
2778static bool isInstantiationOfStaticDataMember(VarDecl *Pattern,
2779                                              VarDecl *Instance) {
2780  assert(Instance->isStaticDataMember());
2781
2782  Pattern = Pattern->getCanonicalDecl();
2783
2784  do {
2785    Instance = Instance->getCanonicalDecl();
2786    if (Pattern == Instance) return true;
2787    Instance = Instance->getInstantiatedFromStaticDataMember();
2788  } while (Instance);
2789
2790  return false;
2791}
2792
2793// Other is the prospective instantiation
2794// D is the prospective pattern
2795static bool isInstantiationOf(ASTContext &Ctx, NamedDecl *D, Decl *Other) {
2796  if (D->getKind() != Other->getKind()) {
2797    if (UnresolvedUsingTypenameDecl *UUD
2798          = dyn_cast<UnresolvedUsingTypenameDecl>(D)) {
2799      if (UsingDecl *UD = dyn_cast<UsingDecl>(Other)) {
2800        return isInstantiationOf(UUD, UD, Ctx);
2801      }
2802    }
2803
2804    if (UnresolvedUsingValueDecl *UUD
2805          = dyn_cast<UnresolvedUsingValueDecl>(D)) {
2806      if (UsingDecl *UD = dyn_cast<UsingDecl>(Other)) {
2807        return isInstantiationOf(UUD, UD, Ctx);
2808      }
2809    }
2810
2811    return false;
2812  }
2813
2814  if (CXXRecordDecl *Record = dyn_cast<CXXRecordDecl>(Other))
2815    return isInstantiationOf(cast<CXXRecordDecl>(D), Record);
2816
2817  if (FunctionDecl *Function = dyn_cast<FunctionDecl>(Other))
2818    return isInstantiationOf(cast<FunctionDecl>(D), Function);
2819
2820  if (EnumDecl *Enum = dyn_cast<EnumDecl>(Other))
2821    return isInstantiationOf(cast<EnumDecl>(D), Enum);
2822
2823  if (VarDecl *Var = dyn_cast<VarDecl>(Other))
2824    if (Var->isStaticDataMember())
2825      return isInstantiationOfStaticDataMember(cast<VarDecl>(D), Var);
2826
2827  if (ClassTemplateDecl *Temp = dyn_cast<ClassTemplateDecl>(Other))
2828    return isInstantiationOf(cast<ClassTemplateDecl>(D), Temp);
2829
2830  if (FunctionTemplateDecl *Temp = dyn_cast<FunctionTemplateDecl>(Other))
2831    return isInstantiationOf(cast<FunctionTemplateDecl>(D), Temp);
2832
2833  if (ClassTemplatePartialSpecializationDecl *PartialSpec
2834        = dyn_cast<ClassTemplatePartialSpecializationDecl>(Other))
2835    return isInstantiationOf(cast<ClassTemplatePartialSpecializationDecl>(D),
2836                             PartialSpec);
2837
2838  if (FieldDecl *Field = dyn_cast<FieldDecl>(Other)) {
2839    if (!Field->getDeclName()) {
2840      // This is an unnamed field.
2841      return Ctx.getInstantiatedFromUnnamedFieldDecl(Field) ==
2842        cast<FieldDecl>(D);
2843    }
2844  }
2845
2846  if (UsingDecl *Using = dyn_cast<UsingDecl>(Other))
2847    return isInstantiationOf(cast<UsingDecl>(D), Using, Ctx);
2848
2849  if (UsingShadowDecl *Shadow = dyn_cast<UsingShadowDecl>(Other))
2850    return isInstantiationOf(cast<UsingShadowDecl>(D), Shadow, Ctx);
2851
2852  return D->getDeclName() && isa<NamedDecl>(Other) &&
2853    D->getDeclName() == cast<NamedDecl>(Other)->getDeclName();
2854}
2855
2856template<typename ForwardIterator>
2857static NamedDecl *findInstantiationOf(ASTContext &Ctx,
2858                                      NamedDecl *D,
2859                                      ForwardIterator first,
2860                                      ForwardIterator last) {
2861  for (; first != last; ++first)
2862    if (isInstantiationOf(Ctx, D, *first))
2863      return cast<NamedDecl>(*first);
2864
2865  return 0;
2866}
2867
2868/// \brief Finds the instantiation of the given declaration context
2869/// within the current instantiation.
2870///
2871/// \returns NULL if there was an error
2872DeclContext *Sema::FindInstantiatedContext(SourceLocation Loc, DeclContext* DC,
2873                          const MultiLevelTemplateArgumentList &TemplateArgs) {
2874  if (NamedDecl *D = dyn_cast<NamedDecl>(DC)) {
2875    Decl* ID = FindInstantiatedDecl(Loc, D, TemplateArgs);
2876    return cast_or_null<DeclContext>(ID);
2877  } else return DC;
2878}
2879
2880/// \brief Find the instantiation of the given declaration within the
2881/// current instantiation.
2882///
2883/// This routine is intended to be used when \p D is a declaration
2884/// referenced from within a template, that needs to mapped into the
2885/// corresponding declaration within an instantiation. For example,
2886/// given:
2887///
2888/// \code
2889/// template<typename T>
2890/// struct X {
2891///   enum Kind {
2892///     KnownValue = sizeof(T)
2893///   };
2894///
2895///   bool getKind() const { return KnownValue; }
2896/// };
2897///
2898/// template struct X<int>;
2899/// \endcode
2900///
2901/// In the instantiation of X<int>::getKind(), we need to map the
2902/// EnumConstantDecl for KnownValue (which refers to
2903/// X<T>::<Kind>::KnownValue) to its instantiation
2904/// (X<int>::<Kind>::KnownValue). InstantiateCurrentDeclRef() performs
2905/// this mapping from within the instantiation of X<int>.
2906NamedDecl *Sema::FindInstantiatedDecl(SourceLocation Loc, NamedDecl *D,
2907                          const MultiLevelTemplateArgumentList &TemplateArgs) {
2908  DeclContext *ParentDC = D->getDeclContext();
2909  if (isa<ParmVarDecl>(D) || isa<NonTypeTemplateParmDecl>(D) ||
2910      isa<TemplateTypeParmDecl>(D) || isa<TemplateTemplateParmDecl>(D) ||
2911      (ParentDC->isFunctionOrMethod() && ParentDC->isDependentContext())) {
2912    // D is a local of some kind. Look into the map of local
2913    // declarations to their instantiations.
2914    typedef LocalInstantiationScope::DeclArgumentPack DeclArgumentPack;
2915    llvm::PointerUnion<Decl *, DeclArgumentPack *> *Found
2916      = CurrentInstantiationScope->findInstantiationOf(D);
2917
2918    if (Found) {
2919      if (Decl *FD = Found->dyn_cast<Decl *>())
2920        return cast<NamedDecl>(FD);
2921
2922      unsigned PackIdx = ArgumentPackSubstitutionIndex;
2923      return cast<NamedDecl>((*Found->get<DeclArgumentPack *>())[PackIdx]);
2924    }
2925
2926    // If we didn't find the decl, then we must have a label decl that hasn't
2927    // been found yet.  Lazily instantiate it and return it now.
2928    assert(isa<LabelDecl>(D));
2929
2930    Decl *Inst = SubstDecl(D, CurContext, TemplateArgs);
2931    assert(Inst && "Failed to instantiate label??");
2932
2933    CurrentInstantiationScope->InstantiatedLocal(D, Inst);
2934    return cast<LabelDecl>(Inst);
2935  }
2936
2937  if (CXXRecordDecl *Record = dyn_cast<CXXRecordDecl>(D)) {
2938    if (!Record->isDependentContext())
2939      return D;
2940
2941    // If the RecordDecl is actually the injected-class-name or a
2942    // "templated" declaration for a class template, class template
2943    // partial specialization, or a member class of a class template,
2944    // substitute into the injected-class-name of the class template
2945    // or partial specialization to find the new DeclContext.
2946    QualType T;
2947    ClassTemplateDecl *ClassTemplate = Record->getDescribedClassTemplate();
2948
2949    if (ClassTemplate) {
2950      T = ClassTemplate->getInjectedClassNameSpecialization();
2951    } else if (ClassTemplatePartialSpecializationDecl *PartialSpec
2952                 = dyn_cast<ClassTemplatePartialSpecializationDecl>(Record)) {
2953      ClassTemplate = PartialSpec->getSpecializedTemplate();
2954
2955      // If we call SubstType with an InjectedClassNameType here we
2956      // can end up in an infinite loop.
2957      T = Context.getTypeDeclType(Record);
2958      assert(isa<InjectedClassNameType>(T) &&
2959             "type of partial specialization is not an InjectedClassNameType");
2960      T = cast<InjectedClassNameType>(T)->getInjectedSpecializationType();
2961    }
2962
2963    if (!T.isNull()) {
2964      // Substitute into the injected-class-name to get the type
2965      // corresponding to the instantiation we want, which may also be
2966      // the current instantiation (if we're in a template
2967      // definition). This substitution should never fail, since we
2968      // know we can instantiate the injected-class-name or we
2969      // wouldn't have gotten to the injected-class-name!
2970
2971      // FIXME: Can we use the CurrentInstantiationScope to avoid this
2972      // extra instantiation in the common case?
2973      T = SubstType(T, TemplateArgs, Loc, DeclarationName());
2974      assert(!T.isNull() && "Instantiation of injected-class-name cannot fail.");
2975
2976      if (!T->isDependentType()) {
2977        assert(T->isRecordType() && "Instantiation must produce a record type");
2978        return T->getAs<RecordType>()->getDecl();
2979      }
2980
2981      // We are performing "partial" template instantiation to create
2982      // the member declarations for the members of a class template
2983      // specialization. Therefore, D is actually referring to something
2984      // in the current instantiation. Look through the current
2985      // context, which contains actual instantiations, to find the
2986      // instantiation of the "current instantiation" that D refers
2987      // to.
2988      bool SawNonDependentContext = false;
2989      for (DeclContext *DC = CurContext; !DC->isFileContext();
2990           DC = DC->getParent()) {
2991        if (ClassTemplateSpecializationDecl *Spec
2992                          = dyn_cast<ClassTemplateSpecializationDecl>(DC))
2993          if (isInstantiationOf(ClassTemplate,
2994                                Spec->getSpecializedTemplate()))
2995            return Spec;
2996
2997        if (!DC->isDependentContext())
2998          SawNonDependentContext = true;
2999      }
3000
3001      // We're performing "instantiation" of a member of the current
3002      // instantiation while we are type-checking the
3003      // definition. Compute the declaration context and return that.
3004      assert(!SawNonDependentContext &&
3005             "No dependent context while instantiating record");
3006      DeclContext *DC = computeDeclContext(T);
3007      assert(DC &&
3008             "Unable to find declaration for the current instantiation");
3009      return cast<CXXRecordDecl>(DC);
3010    }
3011
3012    // Fall through to deal with other dependent record types (e.g.,
3013    // anonymous unions in class templates).
3014  }
3015
3016  if (!ParentDC->isDependentContext())
3017    return D;
3018
3019  ParentDC = FindInstantiatedContext(Loc, ParentDC, TemplateArgs);
3020  if (!ParentDC)
3021    return 0;
3022
3023  if (ParentDC != D->getDeclContext()) {
3024    // We performed some kind of instantiation in the parent context,
3025    // so now we need to look into the instantiated parent context to
3026    // find the instantiation of the declaration D.
3027
3028    // If our context used to be dependent, we may need to instantiate
3029    // it before performing lookup into that context.
3030    bool IsBeingInstantiated = false;
3031    if (CXXRecordDecl *Spec = dyn_cast<CXXRecordDecl>(ParentDC)) {
3032      if (!Spec->isDependentContext()) {
3033        QualType T = Context.getTypeDeclType(Spec);
3034        const RecordType *Tag = T->getAs<RecordType>();
3035        assert(Tag && "type of non-dependent record is not a RecordType");
3036        if (Tag->isBeingDefined())
3037          IsBeingInstantiated = true;
3038        if (!Tag->isBeingDefined() &&
3039            RequireCompleteType(Loc, T, diag::err_incomplete_type))
3040          return 0;
3041
3042        ParentDC = Tag->getDecl();
3043      }
3044    }
3045
3046    NamedDecl *Result = 0;
3047    if (D->getDeclName()) {
3048      DeclContext::lookup_result Found = ParentDC->lookup(D->getDeclName());
3049      Result = findInstantiationOf(Context, D, Found.first, Found.second);
3050    } else {
3051      // Since we don't have a name for the entity we're looking for,
3052      // our only option is to walk through all of the declarations to
3053      // find that name. This will occur in a few cases:
3054      //
3055      //   - anonymous struct/union within a template
3056      //   - unnamed class/struct/union/enum within a template
3057      //
3058      // FIXME: Find a better way to find these instantiations!
3059      Result = findInstantiationOf(Context, D,
3060                                   ParentDC->decls_begin(),
3061                                   ParentDC->decls_end());
3062    }
3063
3064    if (!Result) {
3065      if (isa<UsingShadowDecl>(D)) {
3066        // UsingShadowDecls can instantiate to nothing because of using hiding.
3067      } else if (Diags.hasErrorOccurred()) {
3068        // We've already complained about something, so most likely this
3069        // declaration failed to instantiate. There's no point in complaining
3070        // further, since this is normal in invalid code.
3071      } else if (IsBeingInstantiated) {
3072        // The class in which this member exists is currently being
3073        // instantiated, and we haven't gotten around to instantiating this
3074        // member yet. This can happen when the code uses forward declarations
3075        // of member classes, and introduces ordering dependencies via
3076        // template instantiation.
3077        Diag(Loc, diag::err_member_not_yet_instantiated)
3078          << D->getDeclName()
3079          << Context.getTypeDeclType(cast<CXXRecordDecl>(ParentDC));
3080        Diag(D->getLocation(), diag::note_non_instantiated_member_here);
3081      } else {
3082        // We should have found something, but didn't.
3083        llvm_unreachable("Unable to find instantiation of declaration!");
3084      }
3085    }
3086
3087    D = Result;
3088  }
3089
3090  return D;
3091}
3092
3093/// \brief Performs template instantiation for all implicit template
3094/// instantiations we have seen until this point.
3095void Sema::PerformPendingInstantiations(bool LocalOnly) {
3096  while (!PendingLocalImplicitInstantiations.empty() ||
3097         (!LocalOnly && !PendingInstantiations.empty())) {
3098    PendingImplicitInstantiation Inst;
3099
3100    if (PendingLocalImplicitInstantiations.empty()) {
3101      Inst = PendingInstantiations.front();
3102      PendingInstantiations.pop_front();
3103    } else {
3104      Inst = PendingLocalImplicitInstantiations.front();
3105      PendingLocalImplicitInstantiations.pop_front();
3106    }
3107
3108    // Instantiate function definitions
3109    if (FunctionDecl *Function = dyn_cast<FunctionDecl>(Inst.first)) {
3110      PrettyDeclStackTraceEntry CrashInfo(*this, Function, SourceLocation(),
3111                                          "instantiating function definition");
3112      bool DefinitionRequired = Function->getTemplateSpecializationKind() ==
3113                                TSK_ExplicitInstantiationDefinition;
3114      InstantiateFunctionDefinition(/*FIXME:*/Inst.second, Function, true,
3115                                    DefinitionRequired);
3116      continue;
3117    }
3118
3119    // Instantiate static data member definitions.
3120    VarDecl *Var = cast<VarDecl>(Inst.first);
3121    assert(Var->isStaticDataMember() && "Not a static data member?");
3122
3123    // Don't try to instantiate declarations if the most recent redeclaration
3124    // is invalid.
3125    if (Var->getMostRecentDeclaration()->isInvalidDecl())
3126      continue;
3127
3128    // Check if the most recent declaration has changed the specialization kind
3129    // and removed the need for implicit instantiation.
3130    switch (Var->getMostRecentDeclaration()->getTemplateSpecializationKind()) {
3131    case TSK_Undeclared:
3132      assert(false && "Cannot instantitiate an undeclared specialization.");
3133    case TSK_ExplicitInstantiationDeclaration:
3134    case TSK_ExplicitSpecialization:
3135      continue;  // No longer need to instantiate this type.
3136    case TSK_ExplicitInstantiationDefinition:
3137      // We only need an instantiation if the pending instantiation *is* the
3138      // explicit instantiation.
3139      if (Var != Var->getMostRecentDeclaration()) continue;
3140    case TSK_ImplicitInstantiation:
3141      break;
3142    }
3143
3144    PrettyDeclStackTraceEntry CrashInfo(*this, Var, Var->getLocation(),
3145                                        "instantiating static data member "
3146                                        "definition");
3147
3148    bool DefinitionRequired = Var->getTemplateSpecializationKind() ==
3149                              TSK_ExplicitInstantiationDefinition;
3150    InstantiateStaticDataMemberDefinition(/*FIXME:*/Inst.second, Var, true,
3151                                          DefinitionRequired);
3152  }
3153}
3154
3155void Sema::PerformDependentDiagnostics(const DeclContext *Pattern,
3156                       const MultiLevelTemplateArgumentList &TemplateArgs) {
3157  for (DeclContext::ddiag_iterator I = Pattern->ddiag_begin(),
3158         E = Pattern->ddiag_end(); I != E; ++I) {
3159    DependentDiagnostic *DD = *I;
3160
3161    switch (DD->getKind()) {
3162    case DependentDiagnostic::Access:
3163      HandleDependentAccessCheck(*DD, TemplateArgs);
3164      break;
3165    }
3166  }
3167}
3168