SemaTemplateInstantiateDecl.cpp revision 4278c654b645402554eb52a48e9c7097c9f1233a 
1//===--- SemaTemplateInstantiateDecl.cpp - C++ Template Decl Instantiation ===/
2//
3//                     The LLVM Compiler Infrastructure
4//
5// This file is distributed under the University of Illinois Open Source
6// License. See LICENSE.TXT for details.
7//===----------------------------------------------------------------------===/
8//
9//  This file implements C++ template instantiation for declarations.
10//
11//===----------------------------------------------------------------------===/
12#include "clang/Sema/SemaInternal.h"
13#include "clang/Sema/Lookup.h"
14#include "clang/Sema/PrettyDeclStackTrace.h"
15#include "clang/Sema/Template.h"
16#include "clang/AST/ASTConsumer.h"
17#include "clang/AST/ASTContext.h"
18#include "clang/AST/DeclTemplate.h"
19#include "clang/AST/DeclVisitor.h"
20#include "clang/AST/DependentDiagnostic.h"
21#include "clang/AST/Expr.h"
22#include "clang/AST/ExprCXX.h"
23#include "clang/AST/TypeLoc.h"
24#include "clang/Lex/Preprocessor.h"
25
26using namespace clang;
27
28bool TemplateDeclInstantiator::SubstQualifier(const DeclaratorDecl *OldDecl,
29                                              DeclaratorDecl *NewDecl) {
30  if (!OldDecl->getQualifierLoc())
31    return false;
32
33  NestedNameSpecifierLoc NewQualifierLoc
34    = SemaRef.SubstNestedNameSpecifierLoc(OldDecl->getQualifierLoc(),
35                                          TemplateArgs);
36
37  if (!NewQualifierLoc)
38    return true;
39
40  NewDecl->setQualifierInfo(NewQualifierLoc);
41  return false;
42}
43
44bool TemplateDeclInstantiator::SubstQualifier(const TagDecl *OldDecl,
45                                              TagDecl *NewDecl) {
46  if (!OldDecl->getQualifierLoc())
47    return false;
48
49  NestedNameSpecifierLoc NewQualifierLoc
50  = SemaRef.SubstNestedNameSpecifierLoc(OldDecl->getQualifierLoc(),
51                                        TemplateArgs);
52
53  if (!NewQualifierLoc)
54    return true;
55
56  NewDecl->setQualifierInfo(NewQualifierLoc);
57  return false;
58}
59
60// FIXME: Is this still too simple?
61void Sema::InstantiateAttrs(const MultiLevelTemplateArgumentList &TemplateArgs,
62                            const Decl *Tmpl, Decl *New) {
63  for (AttrVec::const_iterator i = Tmpl->attr_begin(), e = Tmpl->attr_end();
64       i != e; ++i) {
65    const Attr *TmplAttr = *i;
66    // FIXME: This should be generalized to more than just the AlignedAttr.
67    if (const AlignedAttr *Aligned = dyn_cast<AlignedAttr>(TmplAttr)) {
68      if (Aligned->isAlignmentDependent()) {
69        // The alignment expression is not potentially evaluated.
70        EnterExpressionEvaluationContext Unevaluated(*this,
71                                                     Sema::Unevaluated);
72
73        if (Aligned->isAlignmentExpr()) {
74          ExprResult Result = SubstExpr(Aligned->getAlignmentExpr(),
75                                        TemplateArgs);
76          if (!Result.isInvalid())
77            AddAlignedAttr(Aligned->getLocation(), New, Result.takeAs<Expr>());
78        }
79        else {
80          TypeSourceInfo *Result = SubstType(Aligned->getAlignmentType(),
81                                             TemplateArgs,
82                                             Aligned->getLocation(),
83                                             DeclarationName());
84          if (Result)
85            AddAlignedAttr(Aligned->getLocation(), New, Result);
86        }
87        continue;
88      }
89    }
90
91    // FIXME: Is cloning correct for all attributes?
92    Attr *NewAttr = TmplAttr->clone(Context);
93    New->addAttr(NewAttr);
94  }
95}
96
97Decl *
98TemplateDeclInstantiator::VisitTranslationUnitDecl(TranslationUnitDecl *D) {
99  assert(false && "Translation units cannot be instantiated");
100  return D;
101}
102
103Decl *
104TemplateDeclInstantiator::VisitLabelDecl(LabelDecl *D) {
105  LabelDecl *Inst = LabelDecl::Create(SemaRef.Context, Owner, D->getLocation(),
106                                      D->getIdentifier());
107  Owner->addDecl(Inst);
108  return Inst;
109}
110
111Decl *
112TemplateDeclInstantiator::VisitNamespaceDecl(NamespaceDecl *D) {
113  assert(false && "Namespaces cannot be instantiated");
114  return D;
115}
116
117Decl *
118TemplateDeclInstantiator::VisitNamespaceAliasDecl(NamespaceAliasDecl *D) {
119  NamespaceAliasDecl *Inst
120    = NamespaceAliasDecl::Create(SemaRef.Context, Owner,
121                                 D->getNamespaceLoc(),
122                                 D->getAliasLoc(),
123                                 D->getIdentifier(),
124                                 D->getQualifierLoc(),
125                                 D->getTargetNameLoc(),
126                                 D->getNamespace());
127  Owner->addDecl(Inst);
128  return Inst;
129}
130
131Decl *TemplateDeclInstantiator::InstantiateTypedefNameDecl(TypedefNameDecl *D,
132                                                           bool IsTypeAlias) {
133  bool Invalid = false;
134  TypeSourceInfo *DI = D->getTypeSourceInfo();
135  if (DI->getType()->isInstantiationDependentType() ||
136      DI->getType()->isVariablyModifiedType()) {
137    DI = SemaRef.SubstType(DI, TemplateArgs,
138                           D->getLocation(), D->getDeclName());
139    if (!DI) {
140      Invalid = true;
141      DI = SemaRef.Context.getTrivialTypeSourceInfo(SemaRef.Context.IntTy);
142    }
143  } else {
144    SemaRef.MarkDeclarationsReferencedInType(D->getLocation(), DI->getType());
145  }
146
147  // Create the new typedef
148  TypedefNameDecl *Typedef;
149  if (IsTypeAlias)
150    Typedef = TypeAliasDecl::Create(SemaRef.Context, Owner, D->getLocStart(),
151                                    D->getLocation(), D->getIdentifier(), DI);
152  else
153    Typedef = TypedefDecl::Create(SemaRef.Context, Owner, D->getLocStart(),
154                                  D->getLocation(), D->getIdentifier(), DI);
155  if (Invalid)
156    Typedef->setInvalidDecl();
157
158  // If the old typedef was the name for linkage purposes of an anonymous
159  // tag decl, re-establish that relationship for the new typedef.
160  if (const TagType *oldTagType = D->getUnderlyingType()->getAs<TagType>()) {
161    TagDecl *oldTag = oldTagType->getDecl();
162    if (oldTag->getTypedefNameForAnonDecl() == D) {
163      TagDecl *newTag = DI->getType()->castAs<TagType>()->getDecl();
164      assert(!newTag->getIdentifier() && !newTag->getTypedefNameForAnonDecl());
165      newTag->setTypedefNameForAnonDecl(Typedef);
166    }
167  }
168
169  if (TypedefNameDecl *Prev = D->getPreviousDeclaration()) {
170    NamedDecl *InstPrev = SemaRef.FindInstantiatedDecl(D->getLocation(), Prev,
171                                                       TemplateArgs);
172    if (!InstPrev)
173      return 0;
174
175    Typedef->setPreviousDeclaration(cast<TypedefNameDecl>(InstPrev));
176  }
177
178  SemaRef.InstantiateAttrs(TemplateArgs, D, Typedef);
179
180  Typedef->setAccess(D->getAccess());
181
182  return Typedef;
183}
184
185Decl *TemplateDeclInstantiator::VisitTypedefDecl(TypedefDecl *D) {
186  Decl *Typedef = InstantiateTypedefNameDecl(D, /*IsTypeAlias=*/false);
187  Owner->addDecl(Typedef);
188  return Typedef;
189}
190
191Decl *TemplateDeclInstantiator::VisitTypeAliasDecl(TypeAliasDecl *D) {
192  Decl *Typedef = InstantiateTypedefNameDecl(D, /*IsTypeAlias=*/true);
193  Owner->addDecl(Typedef);
194  return Typedef;
195}
196
197Decl *
198TemplateDeclInstantiator::VisitTypeAliasTemplateDecl(TypeAliasTemplateDecl *D) {
199  // Create a local instantiation scope for this type alias template, which
200  // will contain the instantiations of the template parameters.
201  LocalInstantiationScope Scope(SemaRef);
202
203  TemplateParameterList *TempParams = D->getTemplateParameters();
204  TemplateParameterList *InstParams = SubstTemplateParams(TempParams);
205  if (!InstParams)
206    return 0;
207
208  TypeAliasDecl *Pattern = D->getTemplatedDecl();
209
210  TypeAliasTemplateDecl *PrevAliasTemplate = 0;
211  if (Pattern->getPreviousDeclaration()) {
212    DeclContext::lookup_result Found = Owner->lookup(Pattern->getDeclName());
213    if (Found.first != Found.second) {
214      PrevAliasTemplate = dyn_cast<TypeAliasTemplateDecl>(*Found.first);
215    }
216  }
217
218  TypeAliasDecl *AliasInst = cast_or_null<TypeAliasDecl>(
219    InstantiateTypedefNameDecl(Pattern, /*IsTypeAlias=*/true));
220  if (!AliasInst)
221    return 0;
222
223  TypeAliasTemplateDecl *Inst
224    = TypeAliasTemplateDecl::Create(SemaRef.Context, Owner, D->getLocation(),
225                                    D->getDeclName(), InstParams, AliasInst);
226  if (PrevAliasTemplate)
227    Inst->setPreviousDeclaration(PrevAliasTemplate);
228
229  Inst->setAccess(D->getAccess());
230
231  if (!PrevAliasTemplate)
232    Inst->setInstantiatedFromMemberTemplate(D);
233
234  Owner->addDecl(Inst);
235
236  return Inst;
237}
238
239/// \brief Instantiate an initializer, breaking it into separate
240/// initialization arguments.
241///
242/// \param Init The initializer to instantiate.
243///
244/// \param TemplateArgs Template arguments to be substituted into the
245/// initializer.
246///
247/// \param NewArgs Will be filled in with the instantiation arguments.
248///
249/// \returns true if an error occurred, false otherwise
250bool Sema::InstantiateInitializer(Expr *Init,
251                            const MultiLevelTemplateArgumentList &TemplateArgs,
252                                  SourceLocation &LParenLoc,
253                                  ASTOwningVector<Expr*> &NewArgs,
254                                  SourceLocation &RParenLoc) {
255  NewArgs.clear();
256  LParenLoc = SourceLocation();
257  RParenLoc = SourceLocation();
258
259  if (!Init)
260    return false;
261
262  if (ExprWithCleanups *ExprTemp = dyn_cast<ExprWithCleanups>(Init))
263    Init = ExprTemp->getSubExpr();
264
265  while (CXXBindTemporaryExpr *Binder = dyn_cast<CXXBindTemporaryExpr>(Init))
266    Init = Binder->getSubExpr();
267
268  if (ImplicitCastExpr *ICE = dyn_cast<ImplicitCastExpr>(Init))
269    Init = ICE->getSubExprAsWritten();
270
271  if (ParenListExpr *ParenList = dyn_cast<ParenListExpr>(Init)) {
272    LParenLoc = ParenList->getLParenLoc();
273    RParenLoc = ParenList->getRParenLoc();
274    return SubstExprs(ParenList->getExprs(), ParenList->getNumExprs(),
275                      true, TemplateArgs, NewArgs);
276  }
277
278  if (CXXConstructExpr *Construct = dyn_cast<CXXConstructExpr>(Init)) {
279    if (!isa<CXXTemporaryObjectExpr>(Construct)) {
280      if (SubstExprs(Construct->getArgs(), Construct->getNumArgs(), true,
281                     TemplateArgs, NewArgs))
282        return true;
283
284      // FIXME: Fake locations!
285      LParenLoc = PP.getLocForEndOfToken(Init->getLocStart());
286      RParenLoc = LParenLoc;
287      return false;
288    }
289  }
290
291  ExprResult Result = SubstExpr(Init, TemplateArgs);
292  if (Result.isInvalid())
293    return true;
294
295  NewArgs.push_back(Result.takeAs<Expr>());
296  return false;
297}
298
299Decl *TemplateDeclInstantiator::VisitVarDecl(VarDecl *D) {
300  // If this is the variable for an anonymous struct or union,
301  // instantiate the anonymous struct/union type first.
302  if (const RecordType *RecordTy = D->getType()->getAs<RecordType>())
303    if (RecordTy->getDecl()->isAnonymousStructOrUnion())
304      if (!VisitCXXRecordDecl(cast<CXXRecordDecl>(RecordTy->getDecl())))
305        return 0;
306
307  // Do substitution on the type of the declaration
308  TypeSourceInfo *DI = SemaRef.SubstType(D->getTypeSourceInfo(),
309                                         TemplateArgs,
310                                         D->getTypeSpecStartLoc(),
311                                         D->getDeclName());
312  if (!DI)
313    return 0;
314
315  if (DI->getType()->isFunctionType()) {
316    SemaRef.Diag(D->getLocation(), diag::err_variable_instantiates_to_function)
317      << D->isStaticDataMember() << DI->getType();
318    return 0;
319  }
320
321  // Build the instantiated declaration
322  VarDecl *Var = VarDecl::Create(SemaRef.Context, Owner,
323                                 D->getInnerLocStart(),
324                                 D->getLocation(), D->getIdentifier(),
325                                 DI->getType(), DI,
326                                 D->getStorageClass(),
327                                 D->getStorageClassAsWritten());
328  Var->setThreadSpecified(D->isThreadSpecified());
329  Var->setCXXDirectInitializer(D->hasCXXDirectInitializer());
330  Var->setCXXForRangeDecl(D->isCXXForRangeDecl());
331
332  // Substitute the nested name specifier, if any.
333  if (SubstQualifier(D, Var))
334    return 0;
335
336  // If we are instantiating a static data member defined
337  // out-of-line, the instantiation will have the same lexical
338  // context (which will be a namespace scope) as the template.
339  if (D->isOutOfLine())
340    Var->setLexicalDeclContext(D->getLexicalDeclContext());
341
342  Var->setAccess(D->getAccess());
343
344  if (!D->isStaticDataMember()) {
345    Var->setUsed(D->isUsed(false));
346    Var->setReferenced(D->isReferenced());
347  }
348
349  // FIXME: In theory, we could have a previous declaration for variables that
350  // are not static data members.
351  bool Redeclaration = false;
352  // FIXME: having to fake up a LookupResult is dumb.
353  LookupResult Previous(SemaRef, Var->getDeclName(), Var->getLocation(),
354                        Sema::LookupOrdinaryName, Sema::ForRedeclaration);
355  if (D->isStaticDataMember())
356    SemaRef.LookupQualifiedName(Previous, Owner, false);
357  SemaRef.CheckVariableDeclaration(Var, Previous, Redeclaration);
358
359  if (D->isOutOfLine()) {
360    if (!D->isStaticDataMember())
361      D->getLexicalDeclContext()->addDecl(Var);
362    Owner->makeDeclVisibleInContext(Var);
363  } else {
364    Owner->addDecl(Var);
365    if (Owner->isFunctionOrMethod())
366      SemaRef.CurrentInstantiationScope->InstantiatedLocal(D, Var);
367  }
368  SemaRef.InstantiateAttrs(TemplateArgs, D, Var);
369
370  // Link instantiations of static data members back to the template from
371  // which they were instantiated.
372  if (Var->isStaticDataMember())
373    SemaRef.Context.setInstantiatedFromStaticDataMember(Var, D,
374                                                     TSK_ImplicitInstantiation);
375
376  if (Var->getAnyInitializer()) {
377    // We already have an initializer in the class.
378  } else if (D->getInit()) {
379    if (Var->isStaticDataMember() && !D->isOutOfLine())
380      SemaRef.PushExpressionEvaluationContext(Sema::Unevaluated);
381    else
382      SemaRef.PushExpressionEvaluationContext(Sema::PotentiallyEvaluated);
383
384    // Instantiate the initializer.
385    SourceLocation LParenLoc, RParenLoc;
386    ASTOwningVector<Expr*> InitArgs(SemaRef);
387    if (!SemaRef.InstantiateInitializer(D->getInit(), TemplateArgs, LParenLoc,
388                                        InitArgs, RParenLoc)) {
389      bool TypeMayContainAuto = true;
390      // Attach the initializer to the declaration, if we have one.
391      if (InitArgs.size() == 0)
392        SemaRef.ActOnUninitializedDecl(Var, TypeMayContainAuto);
393      else if (D->hasCXXDirectInitializer()) {
394        // Add the direct initializer to the declaration.
395        SemaRef.AddCXXDirectInitializerToDecl(Var,
396                                              LParenLoc,
397                                              move_arg(InitArgs),
398                                              RParenLoc,
399                                              TypeMayContainAuto);
400      } else {
401        assert(InitArgs.size() == 1);
402        Expr *Init = InitArgs.take()[0];
403        SemaRef.AddInitializerToDecl(Var, Init, false, TypeMayContainAuto);
404      }
405    } else {
406      // FIXME: Not too happy about invalidating the declaration
407      // because of a bogus initializer.
408      Var->setInvalidDecl();
409    }
410
411    SemaRef.PopExpressionEvaluationContext();
412  } else if ((!Var->isStaticDataMember() || Var->isOutOfLine()) &&
413             !Var->isCXXForRangeDecl())
414    SemaRef.ActOnUninitializedDecl(Var, false);
415
416  // Diagnose unused local variables with dependent types, where the diagnostic
417  // will have been deferred.
418  if (!Var->isInvalidDecl() && Owner->isFunctionOrMethod() && !Var->isUsed() &&
419      D->getType()->isDependentType())
420    SemaRef.DiagnoseUnusedDecl(Var);
421
422  return Var;
423}
424
425Decl *TemplateDeclInstantiator::VisitAccessSpecDecl(AccessSpecDecl *D) {
426  AccessSpecDecl* AD
427    = AccessSpecDecl::Create(SemaRef.Context, D->getAccess(), Owner,
428                             D->getAccessSpecifierLoc(), D->getColonLoc());
429  Owner->addHiddenDecl(AD);
430  return AD;
431}
432
433Decl *TemplateDeclInstantiator::VisitFieldDecl(FieldDecl *D) {
434  bool Invalid = false;
435  TypeSourceInfo *DI = D->getTypeSourceInfo();
436  if (DI->getType()->isInstantiationDependentType() ||
437      DI->getType()->isVariablyModifiedType())  {
438    DI = SemaRef.SubstType(DI, TemplateArgs,
439                           D->getLocation(), D->getDeclName());
440    if (!DI) {
441      DI = D->getTypeSourceInfo();
442      Invalid = true;
443    } else if (DI->getType()->isFunctionType()) {
444      // C++ [temp.arg.type]p3:
445      //   If a declaration acquires a function type through a type
446      //   dependent on a template-parameter and this causes a
447      //   declaration that does not use the syntactic form of a
448      //   function declarator to have function type, the program is
449      //   ill-formed.
450      SemaRef.Diag(D->getLocation(), diag::err_field_instantiates_to_function)
451        << DI->getType();
452      Invalid = true;
453    }
454  } else {
455    SemaRef.MarkDeclarationsReferencedInType(D->getLocation(), DI->getType());
456  }
457
458  Expr *BitWidth = D->getBitWidth();
459  if (Invalid)
460    BitWidth = 0;
461  else if (BitWidth) {
462    // The bit-width expression is not potentially evaluated.
463    EnterExpressionEvaluationContext Unevaluated(SemaRef, Sema::Unevaluated);
464
465    ExprResult InstantiatedBitWidth
466      = SemaRef.SubstExpr(BitWidth, TemplateArgs);
467    if (InstantiatedBitWidth.isInvalid()) {
468      Invalid = true;
469      BitWidth = 0;
470    } else
471      BitWidth = InstantiatedBitWidth.takeAs<Expr>();
472  }
473
474  FieldDecl *Field = SemaRef.CheckFieldDecl(D->getDeclName(),
475                                            DI->getType(), DI,
476                                            cast<RecordDecl>(Owner),
477                                            D->getLocation(),
478                                            D->isMutable(),
479                                            BitWidth,
480                                            D->hasInClassInitializer(),
481                                            D->getTypeSpecStartLoc(),
482                                            D->getAccess(),
483                                            0);
484  if (!Field) {
485    cast<Decl>(Owner)->setInvalidDecl();
486    return 0;
487  }
488
489  SemaRef.InstantiateAttrs(TemplateArgs, D, Field);
490
491  if (Invalid)
492    Field->setInvalidDecl();
493
494  if (!Field->getDeclName()) {
495    // Keep track of where this decl came from.
496    SemaRef.Context.setInstantiatedFromUnnamedFieldDecl(Field, D);
497  }
498  if (CXXRecordDecl *Parent= dyn_cast<CXXRecordDecl>(Field->getDeclContext())) {
499    if (Parent->isAnonymousStructOrUnion() &&
500        Parent->getRedeclContext()->isFunctionOrMethod())
501      SemaRef.CurrentInstantiationScope->InstantiatedLocal(D, Field);
502  }
503
504  Field->setImplicit(D->isImplicit());
505  Field->setAccess(D->getAccess());
506  Owner->addDecl(Field);
507
508  return Field;
509}
510
511Decl *TemplateDeclInstantiator::VisitIndirectFieldDecl(IndirectFieldDecl *D) {
512  NamedDecl **NamedChain =
513    new (SemaRef.Context)NamedDecl*[D->getChainingSize()];
514
515  int i = 0;
516  for (IndirectFieldDecl::chain_iterator PI =
517       D->chain_begin(), PE = D->chain_end();
518       PI != PE; ++PI) {
519    NamedDecl *Next = SemaRef.FindInstantiatedDecl(D->getLocation(), *PI,
520                                              TemplateArgs);
521    if (!Next)
522      return 0;
523
524    NamedChain[i++] = Next;
525  }
526
527  QualType T = cast<FieldDecl>(NamedChain[i-1])->getType();
528  IndirectFieldDecl* IndirectField
529    = IndirectFieldDecl::Create(SemaRef.Context, Owner, D->getLocation(),
530                                D->getIdentifier(), T,
531                                NamedChain, D->getChainingSize());
532
533
534  IndirectField->setImplicit(D->isImplicit());
535  IndirectField->setAccess(D->getAccess());
536  Owner->addDecl(IndirectField);
537  return IndirectField;
538}
539
540Decl *TemplateDeclInstantiator::VisitFriendDecl(FriendDecl *D) {
541  // Handle friend type expressions by simply substituting template
542  // parameters into the pattern type and checking the result.
543  if (TypeSourceInfo *Ty = D->getFriendType()) {
544    TypeSourceInfo *InstTy;
545    // If this is an unsupported friend, don't bother substituting template
546    // arguments into it. The actual type referred to won't be used by any
547    // parts of Clang, and may not be valid for instantiating. Just use the
548    // same info for the instantiated friend.
549    if (D->isUnsupportedFriend()) {
550      InstTy = Ty;
551    } else {
552      InstTy = SemaRef.SubstType(Ty, TemplateArgs,
553                                 D->getLocation(), DeclarationName());
554    }
555    if (!InstTy)
556      return 0;
557
558    FriendDecl *FD = SemaRef.CheckFriendTypeDecl(D->getFriendLoc(), InstTy);
559    if (!FD)
560      return 0;
561
562    FD->setAccess(AS_public);
563    FD->setUnsupportedFriend(D->isUnsupportedFriend());
564    Owner->addDecl(FD);
565    return FD;
566  }
567
568  NamedDecl *ND = D->getFriendDecl();
569  assert(ND && "friend decl must be a decl or a type!");
570
571  // All of the Visit implementations for the various potential friend
572  // declarations have to be carefully written to work for friend
573  // objects, with the most important detail being that the target
574  // decl should almost certainly not be placed in Owner.
575  Decl *NewND = Visit(ND);
576  if (!NewND) return 0;
577
578  FriendDecl *FD =
579    FriendDecl::Create(SemaRef.Context, Owner, D->getLocation(),
580                       cast<NamedDecl>(NewND), D->getFriendLoc());
581  FD->setAccess(AS_public);
582  FD->setUnsupportedFriend(D->isUnsupportedFriend());
583  Owner->addDecl(FD);
584  return FD;
585}
586
587Decl *TemplateDeclInstantiator::VisitStaticAssertDecl(StaticAssertDecl *D) {
588  Expr *AssertExpr = D->getAssertExpr();
589
590  // The expression in a static assertion is not potentially evaluated.
591  EnterExpressionEvaluationContext Unevaluated(SemaRef, Sema::Unevaluated);
592
593  ExprResult InstantiatedAssertExpr
594    = SemaRef.SubstExpr(AssertExpr, TemplateArgs);
595  if (InstantiatedAssertExpr.isInvalid())
596    return 0;
597
598  ExprResult Message(D->getMessage());
599  D->getMessage();
600  return SemaRef.ActOnStaticAssertDeclaration(D->getLocation(),
601                                              InstantiatedAssertExpr.get(),
602                                              Message.get(),
603                                              D->getRParenLoc());
604}
605
606Decl *TemplateDeclInstantiator::VisitEnumDecl(EnumDecl *D) {
607  EnumDecl *Enum = EnumDecl::Create(SemaRef.Context, Owner, D->getLocStart(),
608                                    D->getLocation(), D->getIdentifier(),
609                                    /*PrevDecl=*/0, D->isScoped(),
610                                    D->isScopedUsingClassTag(), D->isFixed());
611  if (D->isFixed()) {
612    if (TypeSourceInfo* TI = D->getIntegerTypeSourceInfo()) {
613      // If we have type source information for the underlying type, it means it
614      // has been explicitly set by the user. Perform substitution on it before
615      // moving on.
616      SourceLocation UnderlyingLoc = TI->getTypeLoc().getBeginLoc();
617      Enum->setIntegerTypeSourceInfo(SemaRef.SubstType(TI,
618                                                       TemplateArgs,
619                                                       UnderlyingLoc,
620                                                       DeclarationName()));
621
622      if (!Enum->getIntegerTypeSourceInfo())
623        Enum->setIntegerType(SemaRef.Context.IntTy);
624    }
625    else {
626      assert(!D->getIntegerType()->isDependentType()
627             && "Dependent type without type source info");
628      Enum->setIntegerType(D->getIntegerType());
629    }
630  }
631
632  SemaRef.InstantiateAttrs(TemplateArgs, D, Enum);
633
634  Enum->setInstantiationOfMemberEnum(D);
635  Enum->setAccess(D->getAccess());
636  if (SubstQualifier(D, Enum)) return 0;
637  Owner->addDecl(Enum);
638  Enum->startDefinition();
639
640  if (D->getDeclContext()->isFunctionOrMethod())
641    SemaRef.CurrentInstantiationScope->InstantiatedLocal(D, Enum);
642
643  SmallVector<Decl*, 4> Enumerators;
644
645  EnumConstantDecl *LastEnumConst = 0;
646  for (EnumDecl::enumerator_iterator EC = D->enumerator_begin(),
647         ECEnd = D->enumerator_end();
648       EC != ECEnd; ++EC) {
649    // The specified value for the enumerator.
650    ExprResult Value = SemaRef.Owned((Expr *)0);
651    if (Expr *UninstValue = EC->getInitExpr()) {
652      // The enumerator's value expression is not potentially evaluated.
653      EnterExpressionEvaluationContext Unevaluated(SemaRef,
654                                                   Sema::Unevaluated);
655
656      Value = SemaRef.SubstExpr(UninstValue, TemplateArgs);
657    }
658
659    // Drop the initial value and continue.
660    bool isInvalid = false;
661    if (Value.isInvalid()) {
662      Value = SemaRef.Owned((Expr *)0);
663      isInvalid = true;
664    }
665
666    EnumConstantDecl *EnumConst
667      = SemaRef.CheckEnumConstant(Enum, LastEnumConst,
668                                  EC->getLocation(), EC->getIdentifier(),
669                                  Value.get());
670
671    if (isInvalid) {
672      if (EnumConst)
673        EnumConst->setInvalidDecl();
674      Enum->setInvalidDecl();
675    }
676
677    if (EnumConst) {
678      SemaRef.InstantiateAttrs(TemplateArgs, *EC, EnumConst);
679
680      EnumConst->setAccess(Enum->getAccess());
681      Enum->addDecl(EnumConst);
682      Enumerators.push_back(EnumConst);
683      LastEnumConst = EnumConst;
684
685      if (D->getDeclContext()->isFunctionOrMethod()) {
686        // If the enumeration is within a function or method, record the enum
687        // constant as a local.
688        SemaRef.CurrentInstantiationScope->InstantiatedLocal(*EC, EnumConst);
689      }
690    }
691  }
692
693  // FIXME: Fixup LBraceLoc and RBraceLoc
694  // FIXME: Empty Scope and AttributeList (required to handle attribute packed).
695  SemaRef.ActOnEnumBody(Enum->getLocation(), SourceLocation(), SourceLocation(),
696                        Enum,
697                        Enumerators.data(), Enumerators.size(),
698                        0, 0);
699
700  return Enum;
701}
702
703Decl *TemplateDeclInstantiator::VisitEnumConstantDecl(EnumConstantDecl *D) {
704  assert(false && "EnumConstantDecls can only occur within EnumDecls.");
705  return 0;
706}
707
708Decl *TemplateDeclInstantiator::VisitClassTemplateDecl(ClassTemplateDecl *D) {
709  bool isFriend = (D->getFriendObjectKind() != Decl::FOK_None);
710
711  // Create a local instantiation scope for this class template, which
712  // will contain the instantiations of the template parameters.
713  LocalInstantiationScope Scope(SemaRef);
714  TemplateParameterList *TempParams = D->getTemplateParameters();
715  TemplateParameterList *InstParams = SubstTemplateParams(TempParams);
716  if (!InstParams)
717    return NULL;
718
719  CXXRecordDecl *Pattern = D->getTemplatedDecl();
720
721  // Instantiate the qualifier.  We have to do this first in case
722  // we're a friend declaration, because if we are then we need to put
723  // the new declaration in the appropriate context.
724  NestedNameSpecifierLoc QualifierLoc = Pattern->getQualifierLoc();
725  if (QualifierLoc) {
726    QualifierLoc = SemaRef.SubstNestedNameSpecifierLoc(QualifierLoc,
727                                                       TemplateArgs);
728    if (!QualifierLoc)
729      return 0;
730  }
731
732  CXXRecordDecl *PrevDecl = 0;
733  ClassTemplateDecl *PrevClassTemplate = 0;
734
735  if (!isFriend && Pattern->getPreviousDeclaration()) {
736    DeclContext::lookup_result Found = Owner->lookup(Pattern->getDeclName());
737    if (Found.first != Found.second) {
738      PrevClassTemplate = dyn_cast<ClassTemplateDecl>(*Found.first);
739      if (PrevClassTemplate)
740        PrevDecl = PrevClassTemplate->getTemplatedDecl();
741    }
742  }
743
744  // If this isn't a friend, then it's a member template, in which
745  // case we just want to build the instantiation in the
746  // specialization.  If it is a friend, we want to build it in
747  // the appropriate context.
748  DeclContext *DC = Owner;
749  if (isFriend) {
750    if (QualifierLoc) {
751      CXXScopeSpec SS;
752      SS.Adopt(QualifierLoc);
753      DC = SemaRef.computeDeclContext(SS);
754      if (!DC) return 0;
755    } else {
756      DC = SemaRef.FindInstantiatedContext(Pattern->getLocation(),
757                                           Pattern->getDeclContext(),
758                                           TemplateArgs);
759    }
760
761    // Look for a previous declaration of the template in the owning
762    // context.
763    LookupResult R(SemaRef, Pattern->getDeclName(), Pattern->getLocation(),
764                   Sema::LookupOrdinaryName, Sema::ForRedeclaration);
765    SemaRef.LookupQualifiedName(R, DC);
766
767    if (R.isSingleResult()) {
768      PrevClassTemplate = R.getAsSingle<ClassTemplateDecl>();
769      if (PrevClassTemplate)
770        PrevDecl = PrevClassTemplate->getTemplatedDecl();
771    }
772
773    if (!PrevClassTemplate && QualifierLoc) {
774      SemaRef.Diag(Pattern->getLocation(), diag::err_not_tag_in_scope)
775        << D->getTemplatedDecl()->getTagKind() << Pattern->getDeclName() << DC
776        << QualifierLoc.getSourceRange();
777      return 0;
778    }
779
780    bool AdoptedPreviousTemplateParams = false;
781    if (PrevClassTemplate) {
782      bool Complain = true;
783
784      // HACK: libstdc++ 4.2.1 contains an ill-formed friend class
785      // template for struct std::tr1::__detail::_Map_base, where the
786      // template parameters of the friend declaration don't match the
787      // template parameters of the original declaration. In this one
788      // case, we don't complain about the ill-formed friend
789      // declaration.
790      if (isFriend && Pattern->getIdentifier() &&
791          Pattern->getIdentifier()->isStr("_Map_base") &&
792          DC->isNamespace() &&
793          cast<NamespaceDecl>(DC)->getIdentifier() &&
794          cast<NamespaceDecl>(DC)->getIdentifier()->isStr("__detail")) {
795        DeclContext *DCParent = DC->getParent();
796        if (DCParent->isNamespace() &&
797            cast<NamespaceDecl>(DCParent)->getIdentifier() &&
798            cast<NamespaceDecl>(DCParent)->getIdentifier()->isStr("tr1")) {
799          DeclContext *DCParent2 = DCParent->getParent();
800          if (DCParent2->isNamespace() &&
801              cast<NamespaceDecl>(DCParent2)->getIdentifier() &&
802              cast<NamespaceDecl>(DCParent2)->getIdentifier()->isStr("std") &&
803              DCParent2->getParent()->isTranslationUnit())
804            Complain = false;
805        }
806      }
807
808      TemplateParameterList *PrevParams
809        = PrevClassTemplate->getTemplateParameters();
810
811      // Make sure the parameter lists match.
812      if (!SemaRef.TemplateParameterListsAreEqual(InstParams, PrevParams,
813                                                  Complain,
814                                                  Sema::TPL_TemplateMatch)) {
815        if (Complain)
816          return 0;
817
818        AdoptedPreviousTemplateParams = true;
819        InstParams = PrevParams;
820      }
821
822      // Do some additional validation, then merge default arguments
823      // from the existing declarations.
824      if (!AdoptedPreviousTemplateParams &&
825          SemaRef.CheckTemplateParameterList(InstParams, PrevParams,
826                                             Sema::TPC_ClassTemplate))
827        return 0;
828    }
829  }
830
831  CXXRecordDecl *RecordInst
832    = CXXRecordDecl::Create(SemaRef.Context, Pattern->getTagKind(), DC,
833                            Pattern->getLocStart(), Pattern->getLocation(),
834                            Pattern->getIdentifier(), PrevDecl,
835                            /*DelayTypeCreation=*/true);
836
837  if (QualifierLoc)
838    RecordInst->setQualifierInfo(QualifierLoc);
839
840  ClassTemplateDecl *Inst
841    = ClassTemplateDecl::Create(SemaRef.Context, DC, D->getLocation(),
842                                D->getIdentifier(), InstParams, RecordInst,
843                                PrevClassTemplate);
844  RecordInst->setDescribedClassTemplate(Inst);
845
846  if (isFriend) {
847    if (PrevClassTemplate)
848      Inst->setAccess(PrevClassTemplate->getAccess());
849    else
850      Inst->setAccess(D->getAccess());
851
852    Inst->setObjectOfFriendDecl(PrevClassTemplate != 0);
853    // TODO: do we want to track the instantiation progeny of this
854    // friend target decl?
855  } else {
856    Inst->setAccess(D->getAccess());
857    if (!PrevClassTemplate)
858      Inst->setInstantiatedFromMemberTemplate(D);
859  }
860
861  // Trigger creation of the type for the instantiation.
862  SemaRef.Context.getInjectedClassNameType(RecordInst,
863                                    Inst->getInjectedClassNameSpecialization());
864
865  // Finish handling of friends.
866  if (isFriend) {
867    DC->makeDeclVisibleInContext(Inst, /*Recoverable*/ false);
868    return Inst;
869  }
870
871  Owner->addDecl(Inst);
872
873  if (!PrevClassTemplate) {
874    // Queue up any out-of-line partial specializations of this member
875    // class template; the client will force their instantiation once
876    // the enclosing class has been instantiated.
877    SmallVector<ClassTemplatePartialSpecializationDecl *, 4> PartialSpecs;
878    D->getPartialSpecializations(PartialSpecs);
879    for (unsigned I = 0, N = PartialSpecs.size(); I != N; ++I)
880      if (PartialSpecs[I]->isOutOfLine())
881        OutOfLinePartialSpecs.push_back(std::make_pair(Inst, PartialSpecs[I]));
882  }
883
884  return Inst;
885}
886
887Decl *
888TemplateDeclInstantiator::VisitClassTemplatePartialSpecializationDecl(
889                                   ClassTemplatePartialSpecializationDecl *D) {
890  ClassTemplateDecl *ClassTemplate = D->getSpecializedTemplate();
891
892  // Lookup the already-instantiated declaration in the instantiation
893  // of the class template and return that.
894  DeclContext::lookup_result Found
895    = Owner->lookup(ClassTemplate->getDeclName());
896  if (Found.first == Found.second)
897    return 0;
898
899  ClassTemplateDecl *InstClassTemplate
900    = dyn_cast<ClassTemplateDecl>(*Found.first);
901  if (!InstClassTemplate)
902    return 0;
903
904  if (ClassTemplatePartialSpecializationDecl *Result
905        = InstClassTemplate->findPartialSpecInstantiatedFromMember(D))
906    return Result;
907
908  return InstantiateClassTemplatePartialSpecialization(InstClassTemplate, D);
909}
910
911Decl *
912TemplateDeclInstantiator::VisitFunctionTemplateDecl(FunctionTemplateDecl *D) {
913  // Create a local instantiation scope for this function template, which
914  // will contain the instantiations of the template parameters and then get
915  // merged with the local instantiation scope for the function template
916  // itself.
917  LocalInstantiationScope Scope(SemaRef);
918
919  TemplateParameterList *TempParams = D->getTemplateParameters();
920  TemplateParameterList *InstParams = SubstTemplateParams(TempParams);
921  if (!InstParams)
922    return NULL;
923
924  FunctionDecl *Instantiated = 0;
925  if (CXXMethodDecl *DMethod = dyn_cast<CXXMethodDecl>(D->getTemplatedDecl()))
926    Instantiated = cast_or_null<FunctionDecl>(VisitCXXMethodDecl(DMethod,
927                                                                 InstParams));
928  else
929    Instantiated = cast_or_null<FunctionDecl>(VisitFunctionDecl(
930                                                          D->getTemplatedDecl(),
931                                                                InstParams));
932
933  if (!Instantiated)
934    return 0;
935
936  Instantiated->setAccess(D->getAccess());
937
938  // Link the instantiated function template declaration to the function
939  // template from which it was instantiated.
940  FunctionTemplateDecl *InstTemplate
941    = Instantiated->getDescribedFunctionTemplate();
942  InstTemplate->setAccess(D->getAccess());
943  assert(InstTemplate &&
944         "VisitFunctionDecl/CXXMethodDecl didn't create a template!");
945
946  bool isFriend = (InstTemplate->getFriendObjectKind() != Decl::FOK_None);
947
948  // Link the instantiation back to the pattern *unless* this is a
949  // non-definition friend declaration.
950  if (!InstTemplate->getInstantiatedFromMemberTemplate() &&
951      !(isFriend && !D->getTemplatedDecl()->isThisDeclarationADefinition()))
952    InstTemplate->setInstantiatedFromMemberTemplate(D);
953
954  // Make declarations visible in the appropriate context.
955  if (!isFriend)
956    Owner->addDecl(InstTemplate);
957
958  return InstTemplate;
959}
960
961Decl *TemplateDeclInstantiator::VisitCXXRecordDecl(CXXRecordDecl *D) {
962  CXXRecordDecl *PrevDecl = 0;
963  if (D->isInjectedClassName())
964    PrevDecl = cast<CXXRecordDecl>(Owner);
965  else if (D->getPreviousDeclaration()) {
966    NamedDecl *Prev = SemaRef.FindInstantiatedDecl(D->getLocation(),
967                                                   D->getPreviousDeclaration(),
968                                                   TemplateArgs);
969    if (!Prev) return 0;
970    PrevDecl = cast<CXXRecordDecl>(Prev);
971  }
972
973  CXXRecordDecl *Record
974    = CXXRecordDecl::Create(SemaRef.Context, D->getTagKind(), Owner,
975                            D->getLocStart(), D->getLocation(),
976                            D->getIdentifier(), PrevDecl);
977
978  // Substitute the nested name specifier, if any.
979  if (SubstQualifier(D, Record))
980    return 0;
981
982  Record->setImplicit(D->isImplicit());
983  // FIXME: Check against AS_none is an ugly hack to work around the issue that
984  // the tag decls introduced by friend class declarations don't have an access
985  // specifier. Remove once this area of the code gets sorted out.
986  if (D->getAccess() != AS_none)
987    Record->setAccess(D->getAccess());
988  if (!D->isInjectedClassName())
989    Record->setInstantiationOfMemberClass(D, TSK_ImplicitInstantiation);
990
991  // If the original function was part of a friend declaration,
992  // inherit its namespace state.
993  if (Decl::FriendObjectKind FOK = D->getFriendObjectKind())
994    Record->setObjectOfFriendDecl(FOK == Decl::FOK_Declared);
995
996  // Make sure that anonymous structs and unions are recorded.
997  if (D->isAnonymousStructOrUnion()) {
998    Record->setAnonymousStructOrUnion(true);
999    if (Record->getDeclContext()->getRedeclContext()->isFunctionOrMethod())
1000      SemaRef.CurrentInstantiationScope->InstantiatedLocal(D, Record);
1001  }
1002
1003  Owner->addDecl(Record);
1004  return Record;
1005}
1006
1007/// Normal class members are of more specific types and therefore
1008/// don't make it here.  This function serves two purposes:
1009///   1) instantiating function templates
1010///   2) substituting friend declarations
1011/// FIXME: preserve function definitions in case #2
1012Decl *TemplateDeclInstantiator::VisitFunctionDecl(FunctionDecl *D,
1013                                       TemplateParameterList *TemplateParams) {
1014  // Check whether there is already a function template specialization for
1015  // this declaration.
1016  FunctionTemplateDecl *FunctionTemplate = D->getDescribedFunctionTemplate();
1017  void *InsertPos = 0;
1018  if (FunctionTemplate && !TemplateParams) {
1019    std::pair<const TemplateArgument *, unsigned> Innermost
1020      = TemplateArgs.getInnermost();
1021
1022    FunctionDecl *SpecFunc
1023      = FunctionTemplate->findSpecialization(Innermost.first, Innermost.second,
1024                                             InsertPos);
1025
1026    // If we already have a function template specialization, return it.
1027    if (SpecFunc)
1028      return SpecFunc;
1029  }
1030
1031  bool isFriend;
1032  if (FunctionTemplate)
1033    isFriend = (FunctionTemplate->getFriendObjectKind() != Decl::FOK_None);
1034  else
1035    isFriend = (D->getFriendObjectKind() != Decl::FOK_None);
1036
1037  bool MergeWithParentScope = (TemplateParams != 0) ||
1038    Owner->isFunctionOrMethod() ||
1039    !(isa<Decl>(Owner) &&
1040      cast<Decl>(Owner)->isDefinedOutsideFunctionOrMethod());
1041  LocalInstantiationScope Scope(SemaRef, MergeWithParentScope);
1042
1043  SmallVector<ParmVarDecl *, 4> Params;
1044  TypeSourceInfo *TInfo = D->getTypeSourceInfo();
1045  TInfo = SubstFunctionType(D, Params);
1046  if (!TInfo)
1047    return 0;
1048  QualType T = TInfo->getType();
1049
1050  NestedNameSpecifierLoc QualifierLoc = D->getQualifierLoc();
1051  if (QualifierLoc) {
1052    QualifierLoc = SemaRef.SubstNestedNameSpecifierLoc(QualifierLoc,
1053                                                       TemplateArgs);
1054    if (!QualifierLoc)
1055      return 0;
1056  }
1057
1058  // If we're instantiating a local function declaration, put the result
1059  // in the owner;  otherwise we need to find the instantiated context.
1060  DeclContext *DC;
1061  if (D->getDeclContext()->isFunctionOrMethod())
1062    DC = Owner;
1063  else if (isFriend && QualifierLoc) {
1064    CXXScopeSpec SS;
1065    SS.Adopt(QualifierLoc);
1066    DC = SemaRef.computeDeclContext(SS);
1067    if (!DC) return 0;
1068  } else {
1069    DC = SemaRef.FindInstantiatedContext(D->getLocation(), D->getDeclContext(),
1070                                         TemplateArgs);
1071  }
1072
1073  bool isConstexpr = D->isConstexpr();
1074  // FIXME: check whether the instantiation produces a constexpr function.
1075
1076  FunctionDecl *Function =
1077      FunctionDecl::Create(SemaRef.Context, DC, D->getInnerLocStart(),
1078                           D->getLocation(), D->getDeclName(), T, TInfo,
1079                           D->getStorageClass(), D->getStorageClassAsWritten(),
1080                           D->isInlineSpecified(), D->hasWrittenPrototype(),
1081                           isConstexpr);
1082
1083  if (QualifierLoc)
1084    Function->setQualifierInfo(QualifierLoc);
1085
1086  DeclContext *LexicalDC = Owner;
1087  if (!isFriend && D->isOutOfLine()) {
1088    assert(D->getDeclContext()->isFileContext());
1089    LexicalDC = D->getDeclContext();
1090  }
1091
1092  Function->setLexicalDeclContext(LexicalDC);
1093
1094  // Attach the parameters
1095  if (isa<FunctionProtoType>(Function->getType().IgnoreParens())) {
1096    // Adopt the already-instantiated parameters into our own context.
1097    for (unsigned P = 0; P < Params.size(); ++P)
1098      if (Params[P])
1099        Params[P]->setOwningFunction(Function);
1100  } else {
1101    // Since we were instantiated via a typedef of a function type, create
1102    // new parameters.
1103    const FunctionProtoType *Proto
1104      = Function->getType()->getAs<FunctionProtoType>();
1105    assert(Proto && "No function prototype in template instantiation?");
1106    for (FunctionProtoType::arg_type_iterator AI = Proto->arg_type_begin(),
1107         AE = Proto->arg_type_end(); AI != AE; ++AI) {
1108      ParmVarDecl *Param
1109        = SemaRef.BuildParmVarDeclForTypedef(Function, Function->getLocation(),
1110                                             *AI);
1111      Param->setScopeInfo(0, Params.size());
1112      Params.push_back(Param);
1113    }
1114  }
1115  Function->setParams(Params);
1116
1117  SourceLocation InstantiateAtPOI;
1118  if (TemplateParams) {
1119    // Our resulting instantiation is actually a function template, since we
1120    // are substituting only the outer template parameters. For example, given
1121    //
1122    //   template<typename T>
1123    //   struct X {
1124    //     template<typename U> friend void f(T, U);
1125    //   };
1126    //
1127    //   X<int> x;
1128    //
1129    // We are instantiating the friend function template "f" within X<int>,
1130    // which means substituting int for T, but leaving "f" as a friend function
1131    // template.
1132    // Build the function template itself.
1133    FunctionTemplate = FunctionTemplateDecl::Create(SemaRef.Context, DC,
1134                                                    Function->getLocation(),
1135                                                    Function->getDeclName(),
1136                                                    TemplateParams, Function);
1137    Function->setDescribedFunctionTemplate(FunctionTemplate);
1138
1139    FunctionTemplate->setLexicalDeclContext(LexicalDC);
1140
1141    if (isFriend && D->isThisDeclarationADefinition()) {
1142      // TODO: should we remember this connection regardless of whether
1143      // the friend declaration provided a body?
1144      FunctionTemplate->setInstantiatedFromMemberTemplate(
1145                                           D->getDescribedFunctionTemplate());
1146    }
1147  } else if (FunctionTemplate) {
1148    // Record this function template specialization.
1149    std::pair<const TemplateArgument *, unsigned> Innermost
1150      = TemplateArgs.getInnermost();
1151    Function->setFunctionTemplateSpecialization(FunctionTemplate,
1152                            TemplateArgumentList::CreateCopy(SemaRef.Context,
1153                                                             Innermost.first,
1154                                                             Innermost.second),
1155                                                InsertPos);
1156  } else if (isFriend) {
1157    // Note, we need this connection even if the friend doesn't have a body.
1158    // Its body may exist but not have been attached yet due to deferred
1159    // parsing.
1160    // FIXME: It might be cleaner to set this when attaching the body to the
1161    // friend function declaration, however that would require finding all the
1162    // instantiations and modifying them.
1163    Function->setInstantiationOfMemberFunction(D, TSK_ImplicitInstantiation);
1164  }
1165
1166  if (InitFunctionInstantiation(Function, D))
1167    Function->setInvalidDecl();
1168
1169  bool Redeclaration = false;
1170  bool isExplicitSpecialization = false;
1171
1172  LookupResult Previous(SemaRef, Function->getDeclName(), SourceLocation(),
1173                        Sema::LookupOrdinaryName, Sema::ForRedeclaration);
1174
1175  if (DependentFunctionTemplateSpecializationInfo *Info
1176        = D->getDependentSpecializationInfo()) {
1177    assert(isFriend && "non-friend has dependent specialization info?");
1178
1179    // This needs to be set now for future sanity.
1180    Function->setObjectOfFriendDecl(/*HasPrevious*/ true);
1181
1182    // Instantiate the explicit template arguments.
1183    TemplateArgumentListInfo ExplicitArgs(Info->getLAngleLoc(),
1184                                          Info->getRAngleLoc());
1185    if (SemaRef.Subst(Info->getTemplateArgs(), Info->getNumTemplateArgs(),
1186                      ExplicitArgs, TemplateArgs))
1187      return 0;
1188
1189    // Map the candidate templates to their instantiations.
1190    for (unsigned I = 0, E = Info->getNumTemplates(); I != E; ++I) {
1191      Decl *Temp = SemaRef.FindInstantiatedDecl(D->getLocation(),
1192                                                Info->getTemplate(I),
1193                                                TemplateArgs);
1194      if (!Temp) return 0;
1195
1196      Previous.addDecl(cast<FunctionTemplateDecl>(Temp));
1197    }
1198
1199    if (SemaRef.CheckFunctionTemplateSpecialization(Function,
1200                                                    &ExplicitArgs,
1201                                                    Previous))
1202      Function->setInvalidDecl();
1203
1204    isExplicitSpecialization = true;
1205
1206  } else if (TemplateParams || !FunctionTemplate) {
1207    // Look only into the namespace where the friend would be declared to
1208    // find a previous declaration. This is the innermost enclosing namespace,
1209    // as described in ActOnFriendFunctionDecl.
1210    SemaRef.LookupQualifiedName(Previous, DC);
1211
1212    // In C++, the previous declaration we find might be a tag type
1213    // (class or enum). In this case, the new declaration will hide the
1214    // tag type. Note that this does does not apply if we're declaring a
1215    // typedef (C++ [dcl.typedef]p4).
1216    if (Previous.isSingleTagDecl())
1217      Previous.clear();
1218  }
1219
1220  SemaRef.CheckFunctionDeclaration(/*Scope*/ 0, Function, Previous,
1221                                   isExplicitSpecialization, Redeclaration);
1222
1223  NamedDecl *PrincipalDecl = (TemplateParams
1224                              ? cast<NamedDecl>(FunctionTemplate)
1225                              : Function);
1226
1227  // If the original function was part of a friend declaration,
1228  // inherit its namespace state and add it to the owner.
1229  if (isFriend) {
1230    NamedDecl *PrevDecl;
1231    if (TemplateParams)
1232      PrevDecl = FunctionTemplate->getPreviousDeclaration();
1233    else
1234      PrevDecl = Function->getPreviousDeclaration();
1235
1236    PrincipalDecl->setObjectOfFriendDecl(PrevDecl != 0);
1237    DC->makeDeclVisibleInContext(PrincipalDecl, /*Recoverable=*/ false);
1238
1239    bool queuedInstantiation = false;
1240
1241    if (!SemaRef.getLangOptions().CPlusPlus0x &&
1242        D->isThisDeclarationADefinition()) {
1243      // Check for a function body.
1244      const FunctionDecl *Definition = 0;
1245      if (Function->isDefined(Definition) &&
1246          Definition->getTemplateSpecializationKind() == TSK_Undeclared) {
1247        SemaRef.Diag(Function->getLocation(), diag::err_redefinition)
1248          << Function->getDeclName();
1249        SemaRef.Diag(Definition->getLocation(), diag::note_previous_definition);
1250        Function->setInvalidDecl();
1251      }
1252      // Check for redefinitions due to other instantiations of this or
1253      // a similar friend function.
1254      else for (FunctionDecl::redecl_iterator R = Function->redecls_begin(),
1255                                           REnd = Function->redecls_end();
1256                R != REnd; ++R) {
1257        if (*R == Function)
1258          continue;
1259        switch (R->getFriendObjectKind()) {
1260        case Decl::FOK_None:
1261          if (!queuedInstantiation && R->isUsed(false)) {
1262            if (MemberSpecializationInfo *MSInfo
1263                = Function->getMemberSpecializationInfo()) {
1264              if (MSInfo->getPointOfInstantiation().isInvalid()) {
1265                SourceLocation Loc = R->getLocation(); // FIXME
1266                MSInfo->setPointOfInstantiation(Loc);
1267                SemaRef.PendingLocalImplicitInstantiations.push_back(
1268                                                 std::make_pair(Function, Loc));
1269                queuedInstantiation = true;
1270              }
1271            }
1272          }
1273          break;
1274        default:
1275          if (const FunctionDecl *RPattern
1276              = R->getTemplateInstantiationPattern())
1277            if (RPattern->isDefined(RPattern)) {
1278              SemaRef.Diag(Function->getLocation(), diag::err_redefinition)
1279                << Function->getDeclName();
1280              SemaRef.Diag(R->getLocation(), diag::note_previous_definition);
1281              Function->setInvalidDecl();
1282              break;
1283            }
1284        }
1285      }
1286    }
1287  }
1288
1289  if (Function->isOverloadedOperator() && !DC->isRecord() &&
1290      PrincipalDecl->isInIdentifierNamespace(Decl::IDNS_Ordinary))
1291    PrincipalDecl->setNonMemberOperator();
1292
1293  assert(!D->isDefaulted() && "only methods should be defaulted");
1294  return Function;
1295}
1296
1297Decl *
1298TemplateDeclInstantiator::VisitCXXMethodDecl(CXXMethodDecl *D,
1299                                      TemplateParameterList *TemplateParams,
1300                                      bool IsClassScopeSpecialization) {
1301  FunctionTemplateDecl *FunctionTemplate = D->getDescribedFunctionTemplate();
1302  void *InsertPos = 0;
1303  if (FunctionTemplate && !TemplateParams) {
1304    // We are creating a function template specialization from a function
1305    // template. Check whether there is already a function template
1306    // specialization for this particular set of template arguments.
1307    std::pair<const TemplateArgument *, unsigned> Innermost
1308      = TemplateArgs.getInnermost();
1309
1310    FunctionDecl *SpecFunc
1311      = FunctionTemplate->findSpecialization(Innermost.first, Innermost.second,
1312                                             InsertPos);
1313
1314    // If we already have a function template specialization, return it.
1315    if (SpecFunc)
1316      return SpecFunc;
1317  }
1318
1319  bool isFriend;
1320  if (FunctionTemplate)
1321    isFriend = (FunctionTemplate->getFriendObjectKind() != Decl::FOK_None);
1322  else
1323    isFriend = (D->getFriendObjectKind() != Decl::FOK_None);
1324
1325  bool MergeWithParentScope = (TemplateParams != 0) ||
1326    !(isa<Decl>(Owner) &&
1327      cast<Decl>(Owner)->isDefinedOutsideFunctionOrMethod());
1328  LocalInstantiationScope Scope(SemaRef, MergeWithParentScope);
1329
1330  // Instantiate enclosing template arguments for friends.
1331  SmallVector<TemplateParameterList *, 4> TempParamLists;
1332  unsigned NumTempParamLists = 0;
1333  if (isFriend && (NumTempParamLists = D->getNumTemplateParameterLists())) {
1334    TempParamLists.set_size(NumTempParamLists);
1335    for (unsigned I = 0; I != NumTempParamLists; ++I) {
1336      TemplateParameterList *TempParams = D->getTemplateParameterList(I);
1337      TemplateParameterList *InstParams = SubstTemplateParams(TempParams);
1338      if (!InstParams)
1339        return NULL;
1340      TempParamLists[I] = InstParams;
1341    }
1342  }
1343
1344  SmallVector<ParmVarDecl *, 4> Params;
1345  TypeSourceInfo *TInfo = D->getTypeSourceInfo();
1346  TInfo = SubstFunctionType(D, Params);
1347  if (!TInfo)
1348    return 0;
1349  QualType T = TInfo->getType();
1350
1351  // \brief If the type of this function, after ignoring parentheses,
1352  // is not *directly* a function type, then we're instantiating a function
1353  // that was declared via a typedef, e.g.,
1354  //
1355  //   typedef int functype(int, int);
1356  //   functype func;
1357  //
1358  // In this case, we'll just go instantiate the ParmVarDecls that we
1359  // synthesized in the method declaration.
1360  if (!isa<FunctionProtoType>(T.IgnoreParens())) {
1361    assert(!Params.size() && "Instantiating type could not yield parameters");
1362    SmallVector<QualType, 4> ParamTypes;
1363    if (SemaRef.SubstParmTypes(D->getLocation(), D->param_begin(),
1364                               D->getNumParams(), TemplateArgs, ParamTypes,
1365                               &Params))
1366      return 0;
1367  }
1368
1369  NestedNameSpecifierLoc QualifierLoc = D->getQualifierLoc();
1370  if (QualifierLoc) {
1371    QualifierLoc = SemaRef.SubstNestedNameSpecifierLoc(QualifierLoc,
1372                                                 TemplateArgs);
1373    if (!QualifierLoc)
1374      return 0;
1375  }
1376
1377  DeclContext *DC = Owner;
1378  if (isFriend) {
1379    if (QualifierLoc) {
1380      CXXScopeSpec SS;
1381      SS.Adopt(QualifierLoc);
1382      DC = SemaRef.computeDeclContext(SS);
1383
1384      if (DC && SemaRef.RequireCompleteDeclContext(SS, DC))
1385        return 0;
1386    } else {
1387      DC = SemaRef.FindInstantiatedContext(D->getLocation(),
1388                                           D->getDeclContext(),
1389                                           TemplateArgs);
1390    }
1391    if (!DC) return 0;
1392  }
1393
1394  bool isConstexpr = D->isConstexpr();
1395  // FIXME: check whether the instantiation produces a constexpr function.
1396
1397  // Build the instantiated method declaration.
1398  CXXRecordDecl *Record = cast<CXXRecordDecl>(DC);
1399  CXXMethodDecl *Method = 0;
1400
1401  SourceLocation StartLoc = D->getInnerLocStart();
1402  DeclarationNameInfo NameInfo
1403    = SemaRef.SubstDeclarationNameInfo(D->getNameInfo(), TemplateArgs);
1404  if (CXXConstructorDecl *Constructor = dyn_cast<CXXConstructorDecl>(D)) {
1405    Method = CXXConstructorDecl::Create(SemaRef.Context, Record,
1406                                        StartLoc, NameInfo, T, TInfo,
1407                                        Constructor->isExplicit(),
1408                                        Constructor->isInlineSpecified(),
1409                                        false, isConstexpr);
1410  } else if (CXXDestructorDecl *Destructor = dyn_cast<CXXDestructorDecl>(D)) {
1411    Method = CXXDestructorDecl::Create(SemaRef.Context, Record,
1412                                       StartLoc, NameInfo, T, TInfo,
1413                                       Destructor->isInlineSpecified(),
1414                                       false);
1415  } else if (CXXConversionDecl *Conversion = dyn_cast<CXXConversionDecl>(D)) {
1416    Method = CXXConversionDecl::Create(SemaRef.Context, Record,
1417                                       StartLoc, NameInfo, T, TInfo,
1418                                       Conversion->isInlineSpecified(),
1419                                       Conversion->isExplicit(),
1420                                       isConstexpr, Conversion->getLocEnd());
1421  } else {
1422    Method = CXXMethodDecl::Create(SemaRef.Context, Record,
1423                                   StartLoc, NameInfo, T, TInfo,
1424                                   D->isStatic(),
1425                                   D->getStorageClassAsWritten(),
1426                                   D->isInlineSpecified(),
1427                                   isConstexpr, D->getLocEnd());
1428  }
1429
1430  if (QualifierLoc)
1431    Method->setQualifierInfo(QualifierLoc);
1432
1433  if (TemplateParams) {
1434    // Our resulting instantiation is actually a function template, since we
1435    // are substituting only the outer template parameters. For example, given
1436    //
1437    //   template<typename T>
1438    //   struct X {
1439    //     template<typename U> void f(T, U);
1440    //   };
1441    //
1442    //   X<int> x;
1443    //
1444    // We are instantiating the member template "f" within X<int>, which means
1445    // substituting int for T, but leaving "f" as a member function template.
1446    // Build the function template itself.
1447    FunctionTemplate = FunctionTemplateDecl::Create(SemaRef.Context, Record,
1448                                                    Method->getLocation(),
1449                                                    Method->getDeclName(),
1450                                                    TemplateParams, Method);
1451    if (isFriend) {
1452      FunctionTemplate->setLexicalDeclContext(Owner);
1453      FunctionTemplate->setObjectOfFriendDecl(true);
1454    } else if (D->isOutOfLine())
1455      FunctionTemplate->setLexicalDeclContext(D->getLexicalDeclContext());
1456    Method->setDescribedFunctionTemplate(FunctionTemplate);
1457  } else if (FunctionTemplate) {
1458    // Record this function template specialization.
1459    std::pair<const TemplateArgument *, unsigned> Innermost
1460      = TemplateArgs.getInnermost();
1461    Method->setFunctionTemplateSpecialization(FunctionTemplate,
1462                         TemplateArgumentList::CreateCopy(SemaRef.Context,
1463                                                          Innermost.first,
1464                                                          Innermost.second),
1465                                              InsertPos);
1466  } else if (!isFriend) {
1467    // Record that this is an instantiation of a member function.
1468    Method->setInstantiationOfMemberFunction(D, TSK_ImplicitInstantiation);
1469  }
1470
1471  // If we are instantiating a member function defined
1472  // out-of-line, the instantiation will have the same lexical
1473  // context (which will be a namespace scope) as the template.
1474  if (isFriend) {
1475    if (NumTempParamLists)
1476      Method->setTemplateParameterListsInfo(SemaRef.Context,
1477                                            NumTempParamLists,
1478                                            TempParamLists.data());
1479
1480    Method->setLexicalDeclContext(Owner);
1481    Method->setObjectOfFriendDecl(true);
1482  } else if (D->isOutOfLine())
1483    Method->setLexicalDeclContext(D->getLexicalDeclContext());
1484
1485  // Attach the parameters
1486  for (unsigned P = 0; P < Params.size(); ++P)
1487    Params[P]->setOwningFunction(Method);
1488  Method->setParams(Params);
1489
1490  if (InitMethodInstantiation(Method, D))
1491    Method->setInvalidDecl();
1492
1493  LookupResult Previous(SemaRef, NameInfo, Sema::LookupOrdinaryName,
1494                        Sema::ForRedeclaration);
1495
1496  if (!FunctionTemplate || TemplateParams || isFriend) {
1497    SemaRef.LookupQualifiedName(Previous, Record);
1498
1499    // In C++, the previous declaration we find might be a tag type
1500    // (class or enum). In this case, the new declaration will hide the
1501    // tag type. Note that this does does not apply if we're declaring a
1502    // typedef (C++ [dcl.typedef]p4).
1503    if (Previous.isSingleTagDecl())
1504      Previous.clear();
1505  }
1506
1507  bool Redeclaration = false;
1508  if (!IsClassScopeSpecialization)
1509    SemaRef.CheckFunctionDeclaration(0, Method, Previous, false, Redeclaration);
1510
1511  if (D->isPure())
1512    SemaRef.CheckPureMethod(Method, SourceRange());
1513
1514  Method->setAccess(D->getAccess());
1515
1516  SemaRef.CheckOverrideControl(Method);
1517
1518  if (FunctionTemplate) {
1519    // If there's a function template, let our caller handle it.
1520  } else if (Method->isInvalidDecl() && !Previous.empty()) {
1521    // Don't hide a (potentially) valid declaration with an invalid one.
1522  } else {
1523    NamedDecl *DeclToAdd = (TemplateParams
1524                            ? cast<NamedDecl>(FunctionTemplate)
1525                            : Method);
1526    if (isFriend)
1527      Record->makeDeclVisibleInContext(DeclToAdd);
1528    else if (!IsClassScopeSpecialization)
1529      Owner->addDecl(DeclToAdd);
1530  }
1531
1532  if (D->isExplicitlyDefaulted()) {
1533    SemaRef.SetDeclDefaulted(Method, Method->getLocation());
1534  } else {
1535    assert(!D->isDefaulted() &&
1536           "should not implicitly default uninstantiated function");
1537  }
1538
1539  return Method;
1540}
1541
1542Decl *TemplateDeclInstantiator::VisitCXXConstructorDecl(CXXConstructorDecl *D) {
1543  return VisitCXXMethodDecl(D);
1544}
1545
1546Decl *TemplateDeclInstantiator::VisitCXXDestructorDecl(CXXDestructorDecl *D) {
1547  return VisitCXXMethodDecl(D);
1548}
1549
1550Decl *TemplateDeclInstantiator::VisitCXXConversionDecl(CXXConversionDecl *D) {
1551  return VisitCXXMethodDecl(D);
1552}
1553
1554ParmVarDecl *TemplateDeclInstantiator::VisitParmVarDecl(ParmVarDecl *D) {
1555  return SemaRef.SubstParmVarDecl(D, TemplateArgs, /*indexAdjustment*/ 0,
1556                                  llvm::Optional<unsigned>());
1557}
1558
1559Decl *TemplateDeclInstantiator::VisitTemplateTypeParmDecl(
1560                                                    TemplateTypeParmDecl *D) {
1561  // TODO: don't always clone when decls are refcounted.
1562  assert(D->getTypeForDecl()->isTemplateTypeParmType());
1563
1564  TemplateTypeParmDecl *Inst =
1565    TemplateTypeParmDecl::Create(SemaRef.Context, Owner,
1566                                 D->getLocStart(), D->getLocation(),
1567                                 D->getDepth() - TemplateArgs.getNumLevels(),
1568                                 D->getIndex(), D->getIdentifier(),
1569                                 D->wasDeclaredWithTypename(),
1570                                 D->isParameterPack());
1571  Inst->setAccess(AS_public);
1572
1573  if (D->hasDefaultArgument())
1574    Inst->setDefaultArgument(D->getDefaultArgumentInfo(), false);
1575
1576  // Introduce this template parameter's instantiation into the instantiation
1577  // scope.
1578  SemaRef.CurrentInstantiationScope->InstantiatedLocal(D, Inst);
1579
1580  return Inst;
1581}
1582
1583Decl *TemplateDeclInstantiator::VisitNonTypeTemplateParmDecl(
1584                                                 NonTypeTemplateParmDecl *D) {
1585  // Substitute into the type of the non-type template parameter.
1586  TypeLoc TL = D->getTypeSourceInfo()->getTypeLoc();
1587  SmallVector<TypeSourceInfo *, 4> ExpandedParameterPackTypesAsWritten;
1588  SmallVector<QualType, 4> ExpandedParameterPackTypes;
1589  bool IsExpandedParameterPack = false;
1590  TypeSourceInfo *DI;
1591  QualType T;
1592  bool Invalid = false;
1593
1594  if (D->isExpandedParameterPack()) {
1595    // The non-type template parameter pack is an already-expanded pack
1596    // expansion of types. Substitute into each of the expanded types.
1597    ExpandedParameterPackTypes.reserve(D->getNumExpansionTypes());
1598    ExpandedParameterPackTypesAsWritten.reserve(D->getNumExpansionTypes());
1599    for (unsigned I = 0, N = D->getNumExpansionTypes(); I != N; ++I) {
1600      TypeSourceInfo *NewDI =SemaRef.SubstType(D->getExpansionTypeSourceInfo(I),
1601                                               TemplateArgs,
1602                                               D->getLocation(),
1603                                               D->getDeclName());
1604      if (!NewDI)
1605        return 0;
1606
1607      ExpandedParameterPackTypesAsWritten.push_back(NewDI);
1608      QualType NewT =SemaRef.CheckNonTypeTemplateParameterType(NewDI->getType(),
1609                                                              D->getLocation());
1610      if (NewT.isNull())
1611        return 0;
1612      ExpandedParameterPackTypes.push_back(NewT);
1613    }
1614
1615    IsExpandedParameterPack = true;
1616    DI = D->getTypeSourceInfo();
1617    T = DI->getType();
1618  } else if (isa<PackExpansionTypeLoc>(TL)) {
1619    // The non-type template parameter pack's type is a pack expansion of types.
1620    // Determine whether we need to expand this parameter pack into separate
1621    // types.
1622    PackExpansionTypeLoc Expansion = cast<PackExpansionTypeLoc>(TL);
1623    TypeLoc Pattern = Expansion.getPatternLoc();
1624    SmallVector<UnexpandedParameterPack, 2> Unexpanded;
1625    SemaRef.collectUnexpandedParameterPacks(Pattern, Unexpanded);
1626
1627    // Determine whether the set of unexpanded parameter packs can and should
1628    // be expanded.
1629    bool Expand = true;
1630    bool RetainExpansion = false;
1631    llvm::Optional<unsigned> OrigNumExpansions
1632      = Expansion.getTypePtr()->getNumExpansions();
1633    llvm::Optional<unsigned> NumExpansions = OrigNumExpansions;
1634    if (SemaRef.CheckParameterPacksForExpansion(Expansion.getEllipsisLoc(),
1635                                                Pattern.getSourceRange(),
1636                                                Unexpanded.data(),
1637                                                Unexpanded.size(),
1638                                                TemplateArgs,
1639                                                Expand, RetainExpansion,
1640                                                NumExpansions))
1641      return 0;
1642
1643    if (Expand) {
1644      for (unsigned I = 0; I != *NumExpansions; ++I) {
1645        Sema::ArgumentPackSubstitutionIndexRAII SubstIndex(SemaRef, I);
1646        TypeSourceInfo *NewDI = SemaRef.SubstType(Pattern, TemplateArgs,
1647                                                  D->getLocation(),
1648                                                  D->getDeclName());
1649        if (!NewDI)
1650          return 0;
1651
1652        ExpandedParameterPackTypesAsWritten.push_back(NewDI);
1653        QualType NewT = SemaRef.CheckNonTypeTemplateParameterType(
1654                                                              NewDI->getType(),
1655                                                              D->getLocation());
1656        if (NewT.isNull())
1657          return 0;
1658        ExpandedParameterPackTypes.push_back(NewT);
1659      }
1660
1661      // Note that we have an expanded parameter pack. The "type" of this
1662      // expanded parameter pack is the original expansion type, but callers
1663      // will end up using the expanded parameter pack types for type-checking.
1664      IsExpandedParameterPack = true;
1665      DI = D->getTypeSourceInfo();
1666      T = DI->getType();
1667    } else {
1668      // We cannot fully expand the pack expansion now, so substitute into the
1669      // pattern and create a new pack expansion type.
1670      Sema::ArgumentPackSubstitutionIndexRAII SubstIndex(SemaRef, -1);
1671      TypeSourceInfo *NewPattern = SemaRef.SubstType(Pattern, TemplateArgs,
1672                                                     D->getLocation(),
1673                                                     D->getDeclName());
1674      if (!NewPattern)
1675        return 0;
1676
1677      DI = SemaRef.CheckPackExpansion(NewPattern, Expansion.getEllipsisLoc(),
1678                                      NumExpansions);
1679      if (!DI)
1680        return 0;
1681
1682      T = DI->getType();
1683    }
1684  } else {
1685    // Simple case: substitution into a parameter that is not a parameter pack.
1686    DI = SemaRef.SubstType(D->getTypeSourceInfo(), TemplateArgs,
1687                           D->getLocation(), D->getDeclName());
1688    if (!DI)
1689      return 0;
1690
1691    // Check that this type is acceptable for a non-type template parameter.
1692    T = SemaRef.CheckNonTypeTemplateParameterType(DI->getType(),
1693                                                  D->getLocation());
1694    if (T.isNull()) {
1695      T = SemaRef.Context.IntTy;
1696      Invalid = true;
1697    }
1698  }
1699
1700  NonTypeTemplateParmDecl *Param;
1701  if (IsExpandedParameterPack)
1702    Param = NonTypeTemplateParmDecl::Create(SemaRef.Context, Owner,
1703                                            D->getInnerLocStart(),
1704                                            D->getLocation(),
1705                                    D->getDepth() - TemplateArgs.getNumLevels(),
1706                                            D->getPosition(),
1707                                            D->getIdentifier(), T,
1708                                            DI,
1709                                            ExpandedParameterPackTypes.data(),
1710                                            ExpandedParameterPackTypes.size(),
1711                                    ExpandedParameterPackTypesAsWritten.data());
1712  else
1713    Param = NonTypeTemplateParmDecl::Create(SemaRef.Context, Owner,
1714                                            D->getInnerLocStart(),
1715                                            D->getLocation(),
1716                                    D->getDepth() - TemplateArgs.getNumLevels(),
1717                                            D->getPosition(),
1718                                            D->getIdentifier(), T,
1719                                            D->isParameterPack(), DI);
1720
1721  Param->setAccess(AS_public);
1722  if (Invalid)
1723    Param->setInvalidDecl();
1724
1725  Param->setDefaultArgument(D->getDefaultArgument(), false);
1726
1727  // Introduce this template parameter's instantiation into the instantiation
1728  // scope.
1729  SemaRef.CurrentInstantiationScope->InstantiatedLocal(D, Param);
1730  return Param;
1731}
1732
1733Decl *
1734TemplateDeclInstantiator::VisitTemplateTemplateParmDecl(
1735                                                  TemplateTemplateParmDecl *D) {
1736  // Instantiate the template parameter list of the template template parameter.
1737  TemplateParameterList *TempParams = D->getTemplateParameters();
1738  TemplateParameterList *InstParams;
1739  {
1740    // Perform the actual substitution of template parameters within a new,
1741    // local instantiation scope.
1742    LocalInstantiationScope Scope(SemaRef);
1743    InstParams = SubstTemplateParams(TempParams);
1744    if (!InstParams)
1745      return NULL;
1746  }
1747
1748  // Build the template template parameter.
1749  TemplateTemplateParmDecl *Param
1750    = TemplateTemplateParmDecl::Create(SemaRef.Context, Owner, D->getLocation(),
1751                                   D->getDepth() - TemplateArgs.getNumLevels(),
1752                                       D->getPosition(), D->isParameterPack(),
1753                                       D->getIdentifier(), InstParams);
1754  Param->setDefaultArgument(D->getDefaultArgument(), false);
1755  Param->setAccess(AS_public);
1756
1757  // Introduce this template parameter's instantiation into the instantiation
1758  // scope.
1759  SemaRef.CurrentInstantiationScope->InstantiatedLocal(D, Param);
1760
1761  return Param;
1762}
1763
1764Decl *TemplateDeclInstantiator::VisitUsingDirectiveDecl(UsingDirectiveDecl *D) {
1765  // Using directives are never dependent (and never contain any types or
1766  // expressions), so they require no explicit instantiation work.
1767
1768  UsingDirectiveDecl *Inst
1769    = UsingDirectiveDecl::Create(SemaRef.Context, Owner, D->getLocation(),
1770                                 D->getNamespaceKeyLocation(),
1771                                 D->getQualifierLoc(),
1772                                 D->getIdentLocation(),
1773                                 D->getNominatedNamespace(),
1774                                 D->getCommonAncestor());
1775  Owner->addDecl(Inst);
1776  return Inst;
1777}
1778
1779Decl *TemplateDeclInstantiator::VisitUsingDecl(UsingDecl *D) {
1780
1781  // The nested name specifier may be dependent, for example
1782  //     template <typename T> struct t {
1783  //       struct s1 { T f1(); };
1784  //       struct s2 : s1 { using s1::f1; };
1785  //     };
1786  //     template struct t<int>;
1787  // Here, in using s1::f1, s1 refers to t<T>::s1;
1788  // we need to substitute for t<int>::s1.
1789  NestedNameSpecifierLoc QualifierLoc
1790    = SemaRef.SubstNestedNameSpecifierLoc(D->getQualifierLoc(),
1791                                          TemplateArgs);
1792  if (!QualifierLoc)
1793    return 0;
1794
1795  // The name info is non-dependent, so no transformation
1796  // is required.
1797  DeclarationNameInfo NameInfo = D->getNameInfo();
1798
1799  // We only need to do redeclaration lookups if we're in a class
1800  // scope (in fact, it's not really even possible in non-class
1801  // scopes).
1802  bool CheckRedeclaration = Owner->isRecord();
1803
1804  LookupResult Prev(SemaRef, NameInfo, Sema::LookupUsingDeclName,
1805                    Sema::ForRedeclaration);
1806
1807  UsingDecl *NewUD = UsingDecl::Create(SemaRef.Context, Owner,
1808                                       D->getUsingLocation(),
1809                                       QualifierLoc,
1810                                       NameInfo,
1811                                       D->isTypeName());
1812
1813  CXXScopeSpec SS;
1814  SS.Adopt(QualifierLoc);
1815  if (CheckRedeclaration) {
1816    Prev.setHideTags(false);
1817    SemaRef.LookupQualifiedName(Prev, Owner);
1818
1819    // Check for invalid redeclarations.
1820    if (SemaRef.CheckUsingDeclRedeclaration(D->getUsingLocation(),
1821                                            D->isTypeName(), SS,
1822                                            D->getLocation(), Prev))
1823      NewUD->setInvalidDecl();
1824
1825  }
1826
1827  if (!NewUD->isInvalidDecl() &&
1828      SemaRef.CheckUsingDeclQualifier(D->getUsingLocation(), SS,
1829                                      D->getLocation()))
1830    NewUD->setInvalidDecl();
1831
1832  SemaRef.Context.setInstantiatedFromUsingDecl(NewUD, D);
1833  NewUD->setAccess(D->getAccess());
1834  Owner->addDecl(NewUD);
1835
1836  // Don't process the shadow decls for an invalid decl.
1837  if (NewUD->isInvalidDecl())
1838    return NewUD;
1839
1840  bool isFunctionScope = Owner->isFunctionOrMethod();
1841
1842  // Process the shadow decls.
1843  for (UsingDecl::shadow_iterator I = D->shadow_begin(), E = D->shadow_end();
1844         I != E; ++I) {
1845    UsingShadowDecl *Shadow = *I;
1846    NamedDecl *InstTarget =
1847      cast_or_null<NamedDecl>(SemaRef.FindInstantiatedDecl(
1848                                                          Shadow->getLocation(),
1849                                                        Shadow->getTargetDecl(),
1850                                                           TemplateArgs));
1851    if (!InstTarget)
1852      return 0;
1853
1854    if (CheckRedeclaration &&
1855        SemaRef.CheckUsingShadowDecl(NewUD, InstTarget, Prev))
1856      continue;
1857
1858    UsingShadowDecl *InstShadow
1859      = SemaRef.BuildUsingShadowDecl(/*Scope*/ 0, NewUD, InstTarget);
1860    SemaRef.Context.setInstantiatedFromUsingShadowDecl(InstShadow, Shadow);
1861
1862    if (isFunctionScope)
1863      SemaRef.CurrentInstantiationScope->InstantiatedLocal(Shadow, InstShadow);
1864  }
1865
1866  return NewUD;
1867}
1868
1869Decl *TemplateDeclInstantiator::VisitUsingShadowDecl(UsingShadowDecl *D) {
1870  // Ignore these;  we handle them in bulk when processing the UsingDecl.
1871  return 0;
1872}
1873
1874Decl * TemplateDeclInstantiator
1875    ::VisitUnresolvedUsingTypenameDecl(UnresolvedUsingTypenameDecl *D) {
1876  NestedNameSpecifierLoc QualifierLoc
1877    = SemaRef.SubstNestedNameSpecifierLoc(D->getQualifierLoc(),
1878                                          TemplateArgs);
1879  if (!QualifierLoc)
1880    return 0;
1881
1882  CXXScopeSpec SS;
1883  SS.Adopt(QualifierLoc);
1884
1885  // Since NameInfo refers to a typename, it cannot be a C++ special name.
1886  // Hence, no tranformation is required for it.
1887  DeclarationNameInfo NameInfo(D->getDeclName(), D->getLocation());
1888  NamedDecl *UD =
1889    SemaRef.BuildUsingDeclaration(/*Scope*/ 0, D->getAccess(),
1890                                  D->getUsingLoc(), SS, NameInfo, 0,
1891                                  /*instantiation*/ true,
1892                                  /*typename*/ true, D->getTypenameLoc());
1893  if (UD)
1894    SemaRef.Context.setInstantiatedFromUsingDecl(cast<UsingDecl>(UD), D);
1895
1896  return UD;
1897}
1898
1899Decl * TemplateDeclInstantiator
1900    ::VisitUnresolvedUsingValueDecl(UnresolvedUsingValueDecl *D) {
1901  NestedNameSpecifierLoc QualifierLoc
1902      = SemaRef.SubstNestedNameSpecifierLoc(D->getQualifierLoc(), TemplateArgs);
1903  if (!QualifierLoc)
1904    return 0;
1905
1906  CXXScopeSpec SS;
1907  SS.Adopt(QualifierLoc);
1908
1909  DeclarationNameInfo NameInfo
1910    = SemaRef.SubstDeclarationNameInfo(D->getNameInfo(), TemplateArgs);
1911
1912  NamedDecl *UD =
1913    SemaRef.BuildUsingDeclaration(/*Scope*/ 0, D->getAccess(),
1914                                  D->getUsingLoc(), SS, NameInfo, 0,
1915                                  /*instantiation*/ true,
1916                                  /*typename*/ false, SourceLocation());
1917  if (UD)
1918    SemaRef.Context.setInstantiatedFromUsingDecl(cast<UsingDecl>(UD), D);
1919
1920  return UD;
1921}
1922
1923
1924Decl *TemplateDeclInstantiator::VisitClassScopeFunctionSpecializationDecl(
1925                                     ClassScopeFunctionSpecializationDecl *Decl) {
1926  CXXMethodDecl *OldFD = Decl->getSpecialization();
1927  CXXMethodDecl *NewFD = cast<CXXMethodDecl>(VisitCXXMethodDecl(OldFD, 0, true));
1928
1929  LookupResult Previous(SemaRef, NewFD->getNameInfo(), Sema::LookupOrdinaryName,
1930                        Sema::ForRedeclaration);
1931
1932  SemaRef.LookupQualifiedName(Previous, SemaRef.CurContext);
1933  if (SemaRef.CheckFunctionTemplateSpecialization(NewFD, 0, Previous)) {
1934    NewFD->setInvalidDecl();
1935    return NewFD;
1936  }
1937
1938  // Associate the specialization with the pattern.
1939  FunctionDecl *Specialization = cast<FunctionDecl>(Previous.getFoundDecl());
1940  assert(Specialization && "Class scope Specialization is null");
1941  SemaRef.Context.setClassScopeSpecializationPattern(Specialization, OldFD);
1942
1943  return NewFD;
1944}
1945
1946Decl *Sema::SubstDecl(Decl *D, DeclContext *Owner,
1947                      const MultiLevelTemplateArgumentList &TemplateArgs) {
1948  TemplateDeclInstantiator Instantiator(*this, Owner, TemplateArgs);
1949  if (D->isInvalidDecl())
1950    return 0;
1951
1952  return Instantiator.Visit(D);
1953}
1954
1955/// \brief Instantiates a nested template parameter list in the current
1956/// instantiation context.
1957///
1958/// \param L The parameter list to instantiate
1959///
1960/// \returns NULL if there was an error
1961TemplateParameterList *
1962TemplateDeclInstantiator::SubstTemplateParams(TemplateParameterList *L) {
1963  // Get errors for all the parameters before bailing out.
1964  bool Invalid = false;
1965
1966  unsigned N = L->size();
1967  typedef SmallVector<NamedDecl *, 8> ParamVector;
1968  ParamVector Params;
1969  Params.reserve(N);
1970  for (TemplateParameterList::iterator PI = L->begin(), PE = L->end();
1971       PI != PE; ++PI) {
1972    NamedDecl *D = cast_or_null<NamedDecl>(Visit(*PI));
1973    Params.push_back(D);
1974    Invalid = Invalid || !D || D->isInvalidDecl();
1975  }
1976
1977  // Clean up if we had an error.
1978  if (Invalid)
1979    return NULL;
1980
1981  TemplateParameterList *InstL
1982    = TemplateParameterList::Create(SemaRef.Context, L->getTemplateLoc(),
1983                                    L->getLAngleLoc(), &Params.front(), N,
1984                                    L->getRAngleLoc());
1985  return InstL;
1986}
1987
1988/// \brief Instantiate the declaration of a class template partial
1989/// specialization.
1990///
1991/// \param ClassTemplate the (instantiated) class template that is partially
1992// specialized by the instantiation of \p PartialSpec.
1993///
1994/// \param PartialSpec the (uninstantiated) class template partial
1995/// specialization that we are instantiating.
1996///
1997/// \returns The instantiated partial specialization, if successful; otherwise,
1998/// NULL to indicate an error.
1999ClassTemplatePartialSpecializationDecl *
2000TemplateDeclInstantiator::InstantiateClassTemplatePartialSpecialization(
2001                                            ClassTemplateDecl *ClassTemplate,
2002                          ClassTemplatePartialSpecializationDecl *PartialSpec) {
2003  // Create a local instantiation scope for this class template partial
2004  // specialization, which will contain the instantiations of the template
2005  // parameters.
2006  LocalInstantiationScope Scope(SemaRef);
2007
2008  // Substitute into the template parameters of the class template partial
2009  // specialization.
2010  TemplateParameterList *TempParams = PartialSpec->getTemplateParameters();
2011  TemplateParameterList *InstParams = SubstTemplateParams(TempParams);
2012  if (!InstParams)
2013    return 0;
2014
2015  // Substitute into the template arguments of the class template partial
2016  // specialization.
2017  TemplateArgumentListInfo InstTemplateArgs; // no angle locations
2018  if (SemaRef.Subst(PartialSpec->getTemplateArgsAsWritten(),
2019                    PartialSpec->getNumTemplateArgsAsWritten(),
2020                    InstTemplateArgs, TemplateArgs))
2021    return 0;
2022
2023  // Check that the template argument list is well-formed for this
2024  // class template.
2025  SmallVector<TemplateArgument, 4> Converted;
2026  if (SemaRef.CheckTemplateArgumentList(ClassTemplate,
2027                                        PartialSpec->getLocation(),
2028                                        InstTemplateArgs,
2029                                        false,
2030                                        Converted))
2031    return 0;
2032
2033  // Figure out where to insert this class template partial specialization
2034  // in the member template's set of class template partial specializations.
2035  void *InsertPos = 0;
2036  ClassTemplateSpecializationDecl *PrevDecl
2037    = ClassTemplate->findPartialSpecialization(Converted.data(),
2038                                               Converted.size(), InsertPos);
2039
2040  // Build the canonical type that describes the converted template
2041  // arguments of the class template partial specialization.
2042  QualType CanonType
2043    = SemaRef.Context.getTemplateSpecializationType(TemplateName(ClassTemplate),
2044                                                    Converted.data(),
2045                                                    Converted.size());
2046
2047  // Build the fully-sugared type for this class template
2048  // specialization as the user wrote in the specialization
2049  // itself. This means that we'll pretty-print the type retrieved
2050  // from the specialization's declaration the way that the user
2051  // actually wrote the specialization, rather than formatting the
2052  // name based on the "canonical" representation used to store the
2053  // template arguments in the specialization.
2054  TypeSourceInfo *WrittenTy
2055    = SemaRef.Context.getTemplateSpecializationTypeInfo(
2056                                                    TemplateName(ClassTemplate),
2057                                                    PartialSpec->getLocation(),
2058                                                    InstTemplateArgs,
2059                                                    CanonType);
2060
2061  if (PrevDecl) {
2062    // We've already seen a partial specialization with the same template
2063    // parameters and template arguments. This can happen, for example, when
2064    // substituting the outer template arguments ends up causing two
2065    // class template partial specializations of a member class template
2066    // to have identical forms, e.g.,
2067    //
2068    //   template<typename T, typename U>
2069    //   struct Outer {
2070    //     template<typename X, typename Y> struct Inner;
2071    //     template<typename Y> struct Inner<T, Y>;
2072    //     template<typename Y> struct Inner<U, Y>;
2073    //   };
2074    //
2075    //   Outer<int, int> outer; // error: the partial specializations of Inner
2076    //                          // have the same signature.
2077    SemaRef.Diag(PartialSpec->getLocation(), diag::err_partial_spec_redeclared)
2078      << WrittenTy->getType();
2079    SemaRef.Diag(PrevDecl->getLocation(), diag::note_prev_partial_spec_here)
2080      << SemaRef.Context.getTypeDeclType(PrevDecl);
2081    return 0;
2082  }
2083
2084
2085  // Create the class template partial specialization declaration.
2086  ClassTemplatePartialSpecializationDecl *InstPartialSpec
2087    = ClassTemplatePartialSpecializationDecl::Create(SemaRef.Context,
2088                                                     PartialSpec->getTagKind(),
2089                                                     Owner,
2090                                                     PartialSpec->getLocStart(),
2091                                                     PartialSpec->getLocation(),
2092                                                     InstParams,
2093                                                     ClassTemplate,
2094                                                     Converted.data(),
2095                                                     Converted.size(),
2096                                                     InstTemplateArgs,
2097                                                     CanonType,
2098                                                     0,
2099                             ClassTemplate->getNextPartialSpecSequenceNumber());
2100  // Substitute the nested name specifier, if any.
2101  if (SubstQualifier(PartialSpec, InstPartialSpec))
2102    return 0;
2103
2104  InstPartialSpec->setInstantiatedFromMember(PartialSpec);
2105  InstPartialSpec->setTypeAsWritten(WrittenTy);
2106
2107  // Add this partial specialization to the set of class template partial
2108  // specializations.
2109  ClassTemplate->AddPartialSpecialization(InstPartialSpec, InsertPos);
2110  return InstPartialSpec;
2111}
2112
2113TypeSourceInfo*
2114TemplateDeclInstantiator::SubstFunctionType(FunctionDecl *D,
2115                              SmallVectorImpl<ParmVarDecl *> &Params) {
2116  TypeSourceInfo *OldTInfo = D->getTypeSourceInfo();
2117  assert(OldTInfo && "substituting function without type source info");
2118  assert(Params.empty() && "parameter vector is non-empty at start");
2119  TypeSourceInfo *NewTInfo
2120    = SemaRef.SubstFunctionDeclType(OldTInfo, TemplateArgs,
2121                                    D->getTypeSpecStartLoc(),
2122                                    D->getDeclName());
2123  if (!NewTInfo)
2124    return 0;
2125
2126  if (NewTInfo != OldTInfo) {
2127    // Get parameters from the new type info.
2128    TypeLoc OldTL = OldTInfo->getTypeLoc().IgnoreParens();
2129    if (FunctionProtoTypeLoc *OldProtoLoc
2130                                  = dyn_cast<FunctionProtoTypeLoc>(&OldTL)) {
2131      TypeLoc NewTL = NewTInfo->getTypeLoc().IgnoreParens();
2132      FunctionProtoTypeLoc *NewProtoLoc = cast<FunctionProtoTypeLoc>(&NewTL);
2133      assert(NewProtoLoc && "Missing prototype?");
2134      unsigned NewIdx = 0, NumNewParams = NewProtoLoc->getNumArgs();
2135      for (unsigned OldIdx = 0, NumOldParams = OldProtoLoc->getNumArgs();
2136           OldIdx != NumOldParams; ++OldIdx) {
2137        ParmVarDecl *OldParam = OldProtoLoc->getArg(OldIdx);
2138        if (!OldParam->isParameterPack() ||
2139            (NewIdx < NumNewParams &&
2140             NewProtoLoc->getArg(NewIdx)->isParameterPack())) {
2141          // Simple case: normal parameter, or a parameter pack that's
2142          // instantiated to a (still-dependent) parameter pack.
2143          ParmVarDecl *NewParam = NewProtoLoc->getArg(NewIdx++);
2144          Params.push_back(NewParam);
2145          SemaRef.CurrentInstantiationScope->InstantiatedLocal(OldParam,
2146                                                               NewParam);
2147          continue;
2148        }
2149
2150        // Parameter pack: make the instantiation an argument pack.
2151        SemaRef.CurrentInstantiationScope->MakeInstantiatedLocalArgPack(
2152                                                                      OldParam);
2153        unsigned NumArgumentsInExpansion
2154          = SemaRef.getNumArgumentsInExpansion(OldParam->getType(),
2155                                               TemplateArgs);
2156        while (NumArgumentsInExpansion--) {
2157          ParmVarDecl *NewParam = NewProtoLoc->getArg(NewIdx++);
2158          Params.push_back(NewParam);
2159          SemaRef.CurrentInstantiationScope->InstantiatedLocalPackArg(OldParam,
2160                                                                      NewParam);
2161        }
2162      }
2163    }
2164  } else {
2165    // The function type itself was not dependent and therefore no
2166    // substitution occurred. However, we still need to instantiate
2167    // the function parameters themselves.
2168    TypeLoc OldTL = OldTInfo->getTypeLoc().IgnoreParens();
2169    if (FunctionProtoTypeLoc *OldProtoLoc
2170                                    = dyn_cast<FunctionProtoTypeLoc>(&OldTL)) {
2171      for (unsigned i = 0, i_end = OldProtoLoc->getNumArgs(); i != i_end; ++i) {
2172        ParmVarDecl *Parm = VisitParmVarDecl(OldProtoLoc->getArg(i));
2173        if (!Parm)
2174          return 0;
2175        Params.push_back(Parm);
2176      }
2177    }
2178  }
2179  return NewTInfo;
2180}
2181
2182/// \brief Initializes the common fields of an instantiation function
2183/// declaration (New) from the corresponding fields of its template (Tmpl).
2184///
2185/// \returns true if there was an error
2186bool
2187TemplateDeclInstantiator::InitFunctionInstantiation(FunctionDecl *New,
2188                                                    FunctionDecl *Tmpl) {
2189  if (Tmpl->isDeletedAsWritten())
2190    New->setDeletedAsWritten();
2191
2192  // If we are performing substituting explicitly-specified template arguments
2193  // or deduced template arguments into a function template and we reach this
2194  // point, we are now past the point where SFINAE applies and have committed
2195  // to keeping the new function template specialization. We therefore
2196  // convert the active template instantiation for the function template
2197  // into a template instantiation for this specific function template
2198  // specialization, which is not a SFINAE context, so that we diagnose any
2199  // further errors in the declaration itself.
2200  typedef Sema::ActiveTemplateInstantiation ActiveInstType;
2201  ActiveInstType &ActiveInst = SemaRef.ActiveTemplateInstantiations.back();
2202  if (ActiveInst.Kind == ActiveInstType::ExplicitTemplateArgumentSubstitution ||
2203      ActiveInst.Kind == ActiveInstType::DeducedTemplateArgumentSubstitution) {
2204    if (FunctionTemplateDecl *FunTmpl
2205          = dyn_cast<FunctionTemplateDecl>((Decl *)ActiveInst.Entity)) {
2206      assert(FunTmpl->getTemplatedDecl() == Tmpl &&
2207             "Deduction from the wrong function template?");
2208      (void) FunTmpl;
2209      ActiveInst.Kind = ActiveInstType::TemplateInstantiation;
2210      ActiveInst.Entity = reinterpret_cast<uintptr_t>(New);
2211      --SemaRef.NonInstantiationEntries;
2212    }
2213  }
2214
2215  const FunctionProtoType *Proto = Tmpl->getType()->getAs<FunctionProtoType>();
2216  assert(Proto && "Function template without prototype?");
2217
2218  if (Proto->hasExceptionSpec() || Proto->getNoReturnAttr()) {
2219    // The function has an exception specification or a "noreturn"
2220    // attribute. Substitute into each of the exception types.
2221    SmallVector<QualType, 4> Exceptions;
2222    for (unsigned I = 0, N = Proto->getNumExceptions(); I != N; ++I) {
2223      // FIXME: Poor location information!
2224      if (const PackExpansionType *PackExpansion
2225            = Proto->getExceptionType(I)->getAs<PackExpansionType>()) {
2226        // We have a pack expansion. Instantiate it.
2227        SmallVector<UnexpandedParameterPack, 2> Unexpanded;
2228        SemaRef.collectUnexpandedParameterPacks(PackExpansion->getPattern(),
2229                                                Unexpanded);
2230        assert(!Unexpanded.empty() &&
2231               "Pack expansion without parameter packs?");
2232
2233        bool Expand = false;
2234        bool RetainExpansion = false;
2235        llvm::Optional<unsigned> NumExpansions
2236                                          = PackExpansion->getNumExpansions();
2237        if (SemaRef.CheckParameterPacksForExpansion(New->getLocation(),
2238                                                    SourceRange(),
2239                                                    Unexpanded.data(),
2240                                                    Unexpanded.size(),
2241                                                    TemplateArgs,
2242                                                    Expand,
2243                                                    RetainExpansion,
2244                                                    NumExpansions))
2245          break;
2246
2247        if (!Expand) {
2248          // We can't expand this pack expansion into separate arguments yet;
2249          // just substitute into the pattern and create a new pack expansion
2250          // type.
2251          Sema::ArgumentPackSubstitutionIndexRAII SubstIndex(SemaRef, -1);
2252          QualType T = SemaRef.SubstType(PackExpansion->getPattern(),
2253                                         TemplateArgs,
2254                                       New->getLocation(), New->getDeclName());
2255          if (T.isNull())
2256            break;
2257
2258          T = SemaRef.Context.getPackExpansionType(T, NumExpansions);
2259          Exceptions.push_back(T);
2260          continue;
2261        }
2262
2263        // Substitute into the pack expansion pattern for each template
2264        bool Invalid = false;
2265        for (unsigned ArgIdx = 0; ArgIdx != *NumExpansions; ++ArgIdx) {
2266          Sema::ArgumentPackSubstitutionIndexRAII SubstIndex(SemaRef, ArgIdx);
2267
2268          QualType T = SemaRef.SubstType(PackExpansion->getPattern(),
2269                                         TemplateArgs,
2270                                       New->getLocation(), New->getDeclName());
2271          if (T.isNull()) {
2272            Invalid = true;
2273            break;
2274          }
2275
2276          Exceptions.push_back(T);
2277        }
2278
2279        if (Invalid)
2280          break;
2281
2282        continue;
2283      }
2284
2285      QualType T
2286        = SemaRef.SubstType(Proto->getExceptionType(I), TemplateArgs,
2287                            New->getLocation(), New->getDeclName());
2288      if (T.isNull() ||
2289          SemaRef.CheckSpecifiedExceptionType(T, New->getLocation()))
2290        continue;
2291
2292      Exceptions.push_back(T);
2293    }
2294    Expr *NoexceptExpr = 0;
2295    if (Expr *OldNoexceptExpr = Proto->getNoexceptExpr()) {
2296      EnterExpressionEvaluationContext Unevaluated(SemaRef, Sema::Unevaluated);
2297      ExprResult E = SemaRef.SubstExpr(OldNoexceptExpr, TemplateArgs);
2298      if (E.isUsable())
2299        NoexceptExpr = E.take();
2300    }
2301
2302    // Rebuild the function type
2303
2304    FunctionProtoType::ExtProtoInfo EPI = Proto->getExtProtoInfo();
2305    EPI.ExceptionSpecType = Proto->getExceptionSpecType();
2306    EPI.NumExceptions = Exceptions.size();
2307    EPI.Exceptions = Exceptions.data();
2308    EPI.NoexceptExpr = NoexceptExpr;
2309    EPI.ExtInfo = Proto->getExtInfo();
2310
2311    const FunctionProtoType *NewProto
2312      = New->getType()->getAs<FunctionProtoType>();
2313    assert(NewProto && "Template instantiation without function prototype?");
2314    New->setType(SemaRef.Context.getFunctionType(NewProto->getResultType(),
2315                                                 NewProto->arg_type_begin(),
2316                                                 NewProto->getNumArgs(),
2317                                                 EPI));
2318  }
2319
2320  const FunctionDecl* Definition = Tmpl;
2321
2322  // Get the definition. Leaves the variable unchanged if undefined.
2323  Tmpl->isDefined(Definition);
2324
2325  SemaRef.InstantiateAttrs(TemplateArgs, Definition, New);
2326
2327  return false;
2328}
2329
2330/// \brief Initializes common fields of an instantiated method
2331/// declaration (New) from the corresponding fields of its template
2332/// (Tmpl).
2333///
2334/// \returns true if there was an error
2335bool
2336TemplateDeclInstantiator::InitMethodInstantiation(CXXMethodDecl *New,
2337                                                  CXXMethodDecl *Tmpl) {
2338  if (InitFunctionInstantiation(New, Tmpl))
2339    return true;
2340
2341  New->setAccess(Tmpl->getAccess());
2342  if (Tmpl->isVirtualAsWritten())
2343    New->setVirtualAsWritten(true);
2344
2345  // FIXME: attributes
2346  // FIXME: New needs a pointer to Tmpl
2347  return false;
2348}
2349
2350/// \brief Instantiate the definition of the given function from its
2351/// template.
2352///
2353/// \param PointOfInstantiation the point at which the instantiation was
2354/// required. Note that this is not precisely a "point of instantiation"
2355/// for the function, but it's close.
2356///
2357/// \param Function the already-instantiated declaration of a
2358/// function template specialization or member function of a class template
2359/// specialization.
2360///
2361/// \param Recursive if true, recursively instantiates any functions that
2362/// are required by this instantiation.
2363///
2364/// \param DefinitionRequired if true, then we are performing an explicit
2365/// instantiation where the body of the function is required. Complain if
2366/// there is no such body.
2367void Sema::InstantiateFunctionDefinition(SourceLocation PointOfInstantiation,
2368                                         FunctionDecl *Function,
2369                                         bool Recursive,
2370                                         bool DefinitionRequired) {
2371  if (Function->isInvalidDecl() || Function->isDefined())
2372    return;
2373
2374  // Never instantiate an explicit specialization except if it is a class scope
2375  // explicit specialization.
2376  if (Function->getTemplateSpecializationKind() == TSK_ExplicitSpecialization &&
2377      !Function->getClassScopeSpecializationPattern())
2378    return;
2379
2380  // Find the function body that we'll be substituting.
2381  const FunctionDecl *PatternDecl = Function->getTemplateInstantiationPattern();
2382  assert(PatternDecl && "instantiating a non-template");
2383
2384  Stmt *Pattern = PatternDecl->getBody(PatternDecl);
2385  assert(PatternDecl && "template definition is not a template");
2386  if (!Pattern) {
2387    // Try to find a defaulted definition
2388    PatternDecl->isDefined(PatternDecl);
2389  }
2390  assert(PatternDecl && "template definition is not a template");
2391
2392  // Postpone late parsed template instantiations.
2393  if (PatternDecl->isLateTemplateParsed() &&
2394      !LateTemplateParser) {
2395    PendingInstantiations.push_back(
2396      std::make_pair(Function, PointOfInstantiation));
2397    return;
2398  }
2399
2400  // Call the LateTemplateParser callback if there a need to late parse
2401  // a templated function definition.
2402  if (!Pattern && PatternDecl->isLateTemplateParsed() &&
2403      LateTemplateParser) {
2404    LateTemplateParser(OpaqueParser, PatternDecl);
2405    Pattern = PatternDecl->getBody(PatternDecl);
2406  }
2407
2408  if (!Pattern && !PatternDecl->isDefaulted()) {
2409    if (DefinitionRequired) {
2410      if (Function->getPrimaryTemplate())
2411        Diag(PointOfInstantiation,
2412             diag::err_explicit_instantiation_undefined_func_template)
2413          << Function->getPrimaryTemplate();
2414      else
2415        Diag(PointOfInstantiation,
2416             diag::err_explicit_instantiation_undefined_member)
2417          << 1 << Function->getDeclName() << Function->getDeclContext();
2418
2419      if (PatternDecl)
2420        Diag(PatternDecl->getLocation(),
2421             diag::note_explicit_instantiation_here);
2422      Function->setInvalidDecl();
2423    } else if (Function->getTemplateSpecializationKind()
2424                 == TSK_ExplicitInstantiationDefinition) {
2425      PendingInstantiations.push_back(
2426        std::make_pair(Function, PointOfInstantiation));
2427    }
2428
2429    return;
2430  }
2431
2432  // C++0x [temp.explicit]p9:
2433  //   Except for inline functions, other explicit instantiation declarations
2434  //   have the effect of suppressing the implicit instantiation of the entity
2435  //   to which they refer.
2436  if (Function->getTemplateSpecializationKind()
2437        == TSK_ExplicitInstantiationDeclaration &&
2438      !PatternDecl->isInlined())
2439    return;
2440
2441  InstantiatingTemplate Inst(*this, PointOfInstantiation, Function);
2442  if (Inst)
2443    return;
2444
2445  // If we're performing recursive template instantiation, create our own
2446  // queue of pending implicit instantiations that we will instantiate later,
2447  // while we're still within our own instantiation context.
2448  SmallVector<VTableUse, 16> SavedVTableUses;
2449  std::deque<PendingImplicitInstantiation> SavedPendingInstantiations;
2450  if (Recursive) {
2451    VTableUses.swap(SavedVTableUses);
2452    PendingInstantiations.swap(SavedPendingInstantiations);
2453  }
2454
2455  EnterExpressionEvaluationContext EvalContext(*this,
2456                                               Sema::PotentiallyEvaluated);
2457  ActOnStartOfFunctionDef(0, Function);
2458
2459  // Introduce a new scope where local variable instantiations will be
2460  // recorded, unless we're actually a member function within a local
2461  // class, in which case we need to merge our results with the parent
2462  // scope (of the enclosing function).
2463  bool MergeWithParentScope = false;
2464  if (CXXRecordDecl *Rec = dyn_cast<CXXRecordDecl>(Function->getDeclContext()))
2465    MergeWithParentScope = Rec->isLocalClass();
2466
2467  LocalInstantiationScope Scope(*this, MergeWithParentScope);
2468
2469  // Introduce the instantiated function parameters into the local
2470  // instantiation scope, and set the parameter names to those used
2471  // in the template.
2472  unsigned FParamIdx = 0;
2473  for (unsigned I = 0, N = PatternDecl->getNumParams(); I != N; ++I) {
2474    const ParmVarDecl *PatternParam = PatternDecl->getParamDecl(I);
2475    if (!PatternParam->isParameterPack()) {
2476      // Simple case: not a parameter pack.
2477      assert(FParamIdx < Function->getNumParams());
2478      ParmVarDecl *FunctionParam = Function->getParamDecl(I);
2479      FunctionParam->setDeclName(PatternParam->getDeclName());
2480      Scope.InstantiatedLocal(PatternParam, FunctionParam);
2481      ++FParamIdx;
2482      continue;
2483    }
2484
2485    // Expand the parameter pack.
2486    Scope.MakeInstantiatedLocalArgPack(PatternParam);
2487    for (unsigned NumFParams = Function->getNumParams();
2488         FParamIdx < NumFParams;
2489         ++FParamIdx) {
2490      ParmVarDecl *FunctionParam = Function->getParamDecl(FParamIdx);
2491      FunctionParam->setDeclName(PatternParam->getDeclName());
2492      Scope.InstantiatedLocalPackArg(PatternParam, FunctionParam);
2493    }
2494  }
2495
2496  // Enter the scope of this instantiation. We don't use
2497  // PushDeclContext because we don't have a scope.
2498  Sema::ContextRAII savedContext(*this, Function);
2499
2500  MultiLevelTemplateArgumentList TemplateArgs =
2501    getTemplateInstantiationArgs(Function, 0, false, PatternDecl);
2502
2503  if (PatternDecl->isDefaulted()) {
2504    ActOnFinishFunctionBody(Function, 0, /*IsInstantiation=*/true);
2505
2506    SetDeclDefaulted(Function, PatternDecl->getLocation());
2507  } else {
2508    // If this is a constructor, instantiate the member initializers.
2509    if (const CXXConstructorDecl *Ctor =
2510          dyn_cast<CXXConstructorDecl>(PatternDecl)) {
2511      InstantiateMemInitializers(cast<CXXConstructorDecl>(Function), Ctor,
2512                                 TemplateArgs);
2513    }
2514
2515    // Instantiate the function body.
2516    StmtResult Body = SubstStmt(Pattern, TemplateArgs);
2517
2518    if (Body.isInvalid())
2519      Function->setInvalidDecl();
2520
2521    ActOnFinishFunctionBody(Function, Body.get(),
2522                            /*IsInstantiation=*/true);
2523  }
2524
2525  PerformDependentDiagnostics(PatternDecl, TemplateArgs);
2526
2527  savedContext.pop();
2528
2529  DeclGroupRef DG(Function);
2530  Consumer.HandleTopLevelDecl(DG);
2531
2532  // This class may have local implicit instantiations that need to be
2533  // instantiation within this scope.
2534  PerformPendingInstantiations(/*LocalOnly=*/true);
2535  Scope.Exit();
2536
2537  if (Recursive) {
2538    // Define any pending vtables.
2539    DefineUsedVTables();
2540
2541    // Instantiate any pending implicit instantiations found during the
2542    // instantiation of this template.
2543    PerformPendingInstantiations();
2544
2545    // Restore the set of pending vtables.
2546    assert(VTableUses.empty() &&
2547           "VTableUses should be empty before it is discarded.");
2548    VTableUses.swap(SavedVTableUses);
2549
2550    // Restore the set of pending implicit instantiations.
2551    assert(PendingInstantiations.empty() &&
2552           "PendingInstantiations should be empty before it is discarded.");
2553    PendingInstantiations.swap(SavedPendingInstantiations);
2554  }
2555}
2556
2557/// \brief Instantiate the definition of the given variable from its
2558/// template.
2559///
2560/// \param PointOfInstantiation the point at which the instantiation was
2561/// required. Note that this is not precisely a "point of instantiation"
2562/// for the function, but it's close.
2563///
2564/// \param Var the already-instantiated declaration of a static member
2565/// variable of a class template specialization.
2566///
2567/// \param Recursive if true, recursively instantiates any functions that
2568/// are required by this instantiation.
2569///
2570/// \param DefinitionRequired if true, then we are performing an explicit
2571/// instantiation where an out-of-line definition of the member variable
2572/// is required. Complain if there is no such definition.
2573void Sema::InstantiateStaticDataMemberDefinition(
2574                                          SourceLocation PointOfInstantiation,
2575                                                 VarDecl *Var,
2576                                                 bool Recursive,
2577                                                 bool DefinitionRequired) {
2578  if (Var->isInvalidDecl())
2579    return;
2580
2581  // Find the out-of-line definition of this static data member.
2582  VarDecl *Def = Var->getInstantiatedFromStaticDataMember();
2583  assert(Def && "This data member was not instantiated from a template?");
2584  assert(Def->isStaticDataMember() && "Not a static data member?");
2585  Def = Def->getOutOfLineDefinition();
2586
2587  if (!Def) {
2588    // We did not find an out-of-line definition of this static data member,
2589    // so we won't perform any instantiation. Rather, we rely on the user to
2590    // instantiate this definition (or provide a specialization for it) in
2591    // another translation unit.
2592    if (DefinitionRequired) {
2593      Def = Var->getInstantiatedFromStaticDataMember();
2594      Diag(PointOfInstantiation,
2595           diag::err_explicit_instantiation_undefined_member)
2596        << 2 << Var->getDeclName() << Var->getDeclContext();
2597      Diag(Def->getLocation(), diag::note_explicit_instantiation_here);
2598    } else if (Var->getTemplateSpecializationKind()
2599                 == TSK_ExplicitInstantiationDefinition) {
2600      PendingInstantiations.push_back(
2601        std::make_pair(Var, PointOfInstantiation));
2602    }
2603
2604    return;
2605  }
2606
2607  // Never instantiate an explicit specialization.
2608  if (Var->getTemplateSpecializationKind() == TSK_ExplicitSpecialization)
2609    return;
2610
2611  // C++0x [temp.explicit]p9:
2612  //   Except for inline functions, other explicit instantiation declarations
2613  //   have the effect of suppressing the implicit instantiation of the entity
2614  //   to which they refer.
2615  if (Var->getTemplateSpecializationKind()
2616        == TSK_ExplicitInstantiationDeclaration)
2617    return;
2618
2619  // If we already have a definition, we're done.
2620  if (Var->getDefinition())
2621    return;
2622
2623  InstantiatingTemplate Inst(*this, PointOfInstantiation, Var);
2624  if (Inst)
2625    return;
2626
2627  // If we're performing recursive template instantiation, create our own
2628  // queue of pending implicit instantiations that we will instantiate later,
2629  // while we're still within our own instantiation context.
2630  SmallVector<VTableUse, 16> SavedVTableUses;
2631  std::deque<PendingImplicitInstantiation> SavedPendingInstantiations;
2632  if (Recursive) {
2633    VTableUses.swap(SavedVTableUses);
2634    PendingInstantiations.swap(SavedPendingInstantiations);
2635  }
2636
2637  // Enter the scope of this instantiation. We don't use
2638  // PushDeclContext because we don't have a scope.
2639  ContextRAII previousContext(*this, Var->getDeclContext());
2640
2641  VarDecl *OldVar = Var;
2642  Var = cast_or_null<VarDecl>(SubstDecl(Def, Var->getDeclContext(),
2643                                        getTemplateInstantiationArgs(Var)));
2644
2645  previousContext.pop();
2646
2647  if (Var) {
2648    MemberSpecializationInfo *MSInfo = OldVar->getMemberSpecializationInfo();
2649    assert(MSInfo && "Missing member specialization information?");
2650    Var->setTemplateSpecializationKind(MSInfo->getTemplateSpecializationKind(),
2651                                       MSInfo->getPointOfInstantiation());
2652    DeclGroupRef DG(Var);
2653    Consumer.HandleTopLevelDecl(DG);
2654  }
2655
2656  if (Recursive) {
2657    // Define any newly required vtables.
2658    DefineUsedVTables();
2659
2660    // Instantiate any pending implicit instantiations found during the
2661    // instantiation of this template.
2662    PerformPendingInstantiations();
2663
2664    // Restore the set of pending vtables.
2665    assert(VTableUses.empty() &&
2666           "VTableUses should be empty before it is discarded, "
2667           "while instantiating static data member.");
2668    VTableUses.swap(SavedVTableUses);
2669
2670    // Restore the set of pending implicit instantiations.
2671    assert(PendingInstantiations.empty() &&
2672           "PendingInstantiations should be empty before it is discarded, "
2673           "while instantiating static data member.");
2674    PendingInstantiations.swap(SavedPendingInstantiations);
2675  }
2676}
2677
2678void
2679Sema::InstantiateMemInitializers(CXXConstructorDecl *New,
2680                                 const CXXConstructorDecl *Tmpl,
2681                           const MultiLevelTemplateArgumentList &TemplateArgs) {
2682
2683  SmallVector<CXXCtorInitializer*, 4> NewInits;
2684  bool AnyErrors = false;
2685
2686  // Instantiate all the initializers.
2687  for (CXXConstructorDecl::init_const_iterator Inits = Tmpl->init_begin(),
2688                                            InitsEnd = Tmpl->init_end();
2689       Inits != InitsEnd; ++Inits) {
2690    CXXCtorInitializer *Init = *Inits;
2691
2692    // Only instantiate written initializers, let Sema re-construct implicit
2693    // ones.
2694    if (!Init->isWritten())
2695      continue;
2696
2697    SourceLocation LParenLoc, RParenLoc;
2698    ASTOwningVector<Expr*> NewArgs(*this);
2699
2700    SourceLocation EllipsisLoc;
2701
2702    if (Init->isPackExpansion()) {
2703      // This is a pack expansion. We should expand it now.
2704      TypeLoc BaseTL = Init->getBaseClassInfo()->getTypeLoc();
2705      SmallVector<UnexpandedParameterPack, 2> Unexpanded;
2706      collectUnexpandedParameterPacks(BaseTL, Unexpanded);
2707      bool ShouldExpand = false;
2708      bool RetainExpansion = false;
2709      llvm::Optional<unsigned> NumExpansions;
2710      if (CheckParameterPacksForExpansion(Init->getEllipsisLoc(),
2711                                          BaseTL.getSourceRange(),
2712                                          Unexpanded.data(),
2713                                          Unexpanded.size(),
2714                                          TemplateArgs, ShouldExpand,
2715                                          RetainExpansion,
2716                                          NumExpansions)) {
2717        AnyErrors = true;
2718        New->setInvalidDecl();
2719        continue;
2720      }
2721      assert(ShouldExpand && "Partial instantiation of base initializer?");
2722
2723      // Loop over all of the arguments in the argument pack(s),
2724      for (unsigned I = 0; I != *NumExpansions; ++I) {
2725        Sema::ArgumentPackSubstitutionIndexRAII SubstIndex(*this, I);
2726
2727        // Instantiate the initializer.
2728        if (InstantiateInitializer(Init->getInit(), TemplateArgs,
2729                                   LParenLoc, NewArgs, RParenLoc)) {
2730          AnyErrors = true;
2731          break;
2732        }
2733
2734        // Instantiate the base type.
2735        TypeSourceInfo *BaseTInfo = SubstType(Init->getBaseClassInfo(),
2736                                              TemplateArgs,
2737                                              Init->getSourceLocation(),
2738                                              New->getDeclName());
2739        if (!BaseTInfo) {
2740          AnyErrors = true;
2741          break;
2742        }
2743
2744        // Build the initializer.
2745        MemInitResult NewInit = BuildBaseInitializer(BaseTInfo->getType(),
2746                                                     BaseTInfo,
2747                                                     (Expr **)NewArgs.data(),
2748                                                     NewArgs.size(),
2749                                                     Init->getLParenLoc(),
2750                                                     Init->getRParenLoc(),
2751                                                     New->getParent(),
2752                                                     SourceLocation());
2753        if (NewInit.isInvalid()) {
2754          AnyErrors = true;
2755          break;
2756        }
2757
2758        NewInits.push_back(NewInit.get());
2759        NewArgs.clear();
2760      }
2761
2762      continue;
2763    }
2764
2765    // Instantiate the initializer.
2766    if (InstantiateInitializer(Init->getInit(), TemplateArgs,
2767                               LParenLoc, NewArgs, RParenLoc)) {
2768      AnyErrors = true;
2769      continue;
2770    }
2771
2772    MemInitResult NewInit;
2773    if (Init->isBaseInitializer()) {
2774      TypeSourceInfo *BaseTInfo = SubstType(Init->getBaseClassInfo(),
2775                                            TemplateArgs,
2776                                            Init->getSourceLocation(),
2777                                            New->getDeclName());
2778      if (!BaseTInfo) {
2779        AnyErrors = true;
2780        New->setInvalidDecl();
2781        continue;
2782      }
2783
2784      NewInit = BuildBaseInitializer(BaseTInfo->getType(), BaseTInfo,
2785                                     (Expr **)NewArgs.data(),
2786                                     NewArgs.size(),
2787                                     Init->getLParenLoc(),
2788                                     Init->getRParenLoc(),
2789                                     New->getParent(),
2790                                     EllipsisLoc);
2791    } else if (Init->isMemberInitializer()) {
2792      FieldDecl *Member = cast_or_null<FieldDecl>(FindInstantiatedDecl(
2793                                                     Init->getMemberLocation(),
2794                                                     Init->getMember(),
2795                                                     TemplateArgs));
2796      if (!Member) {
2797        AnyErrors = true;
2798        New->setInvalidDecl();
2799        continue;
2800      }
2801
2802      NewInit = BuildMemberInitializer(Member, (Expr **)NewArgs.data(),
2803                                       NewArgs.size(),
2804                                       Init->getSourceLocation(),
2805                                       Init->getLParenLoc(),
2806                                       Init->getRParenLoc());
2807    } else if (Init->isIndirectMemberInitializer()) {
2808      IndirectFieldDecl *IndirectMember =
2809         cast_or_null<IndirectFieldDecl>(FindInstantiatedDecl(
2810                                 Init->getMemberLocation(),
2811                                 Init->getIndirectMember(), TemplateArgs));
2812
2813      if (!IndirectMember) {
2814        AnyErrors = true;
2815        New->setInvalidDecl();
2816        continue;
2817      }
2818
2819      NewInit = BuildMemberInitializer(IndirectMember, (Expr **)NewArgs.data(),
2820                                       NewArgs.size(),
2821                                       Init->getSourceLocation(),
2822                                       Init->getLParenLoc(),
2823                                       Init->getRParenLoc());
2824    }
2825
2826    if (NewInit.isInvalid()) {
2827      AnyErrors = true;
2828      New->setInvalidDecl();
2829    } else {
2830      // FIXME: It would be nice if ASTOwningVector had a release function.
2831      NewArgs.take();
2832
2833      NewInits.push_back(NewInit.get());
2834    }
2835  }
2836
2837  // Assign all the initializers to the new constructor.
2838  ActOnMemInitializers(New,
2839                       /*FIXME: ColonLoc */
2840                       SourceLocation(),
2841                       NewInits.data(), NewInits.size(),
2842                       AnyErrors);
2843}
2844
2845// TODO: this could be templated if the various decl types used the
2846// same method name.
2847static bool isInstantiationOf(ClassTemplateDecl *Pattern,
2848                              ClassTemplateDecl *Instance) {
2849  Pattern = Pattern->getCanonicalDecl();
2850
2851  do {
2852    Instance = Instance->getCanonicalDecl();
2853    if (Pattern == Instance) return true;
2854    Instance = Instance->getInstantiatedFromMemberTemplate();
2855  } while (Instance);
2856
2857  return false;
2858}
2859
2860static bool isInstantiationOf(FunctionTemplateDecl *Pattern,
2861                              FunctionTemplateDecl *Instance) {
2862  Pattern = Pattern->getCanonicalDecl();
2863
2864  do {
2865    Instance = Instance->getCanonicalDecl();
2866    if (Pattern == Instance) return true;
2867    Instance = Instance->getInstantiatedFromMemberTemplate();
2868  } while (Instance);
2869
2870  return false;
2871}
2872
2873static bool
2874isInstantiationOf(ClassTemplatePartialSpecializationDecl *Pattern,
2875                  ClassTemplatePartialSpecializationDecl *Instance) {
2876  Pattern
2877    = cast<ClassTemplatePartialSpecializationDecl>(Pattern->getCanonicalDecl());
2878  do {
2879    Instance = cast<ClassTemplatePartialSpecializationDecl>(
2880                                                Instance->getCanonicalDecl());
2881    if (Pattern == Instance)
2882      return true;
2883    Instance = Instance->getInstantiatedFromMember();
2884  } while (Instance);
2885
2886  return false;
2887}
2888
2889static bool isInstantiationOf(CXXRecordDecl *Pattern,
2890                              CXXRecordDecl *Instance) {
2891  Pattern = Pattern->getCanonicalDecl();
2892
2893  do {
2894    Instance = Instance->getCanonicalDecl();
2895    if (Pattern == Instance) return true;
2896    Instance = Instance->getInstantiatedFromMemberClass();
2897  } while (Instance);
2898
2899  return false;
2900}
2901
2902static bool isInstantiationOf(FunctionDecl *Pattern,
2903                              FunctionDecl *Instance) {
2904  Pattern = Pattern->getCanonicalDecl();
2905
2906  do {
2907    Instance = Instance->getCanonicalDecl();
2908    if (Pattern == Instance) return true;
2909    Instance = Instance->getInstantiatedFromMemberFunction();
2910  } while (Instance);
2911
2912  return false;
2913}
2914
2915static bool isInstantiationOf(EnumDecl *Pattern,
2916                              EnumDecl *Instance) {
2917  Pattern = Pattern->getCanonicalDecl();
2918
2919  do {
2920    Instance = Instance->getCanonicalDecl();
2921    if (Pattern == Instance) return true;
2922    Instance = Instance->getInstantiatedFromMemberEnum();
2923  } while (Instance);
2924
2925  return false;
2926}
2927
2928static bool isInstantiationOf(UsingShadowDecl *Pattern,
2929                              UsingShadowDecl *Instance,
2930                              ASTContext &C) {
2931  return C.getInstantiatedFromUsingShadowDecl(Instance) == Pattern;
2932}
2933
2934static bool isInstantiationOf(UsingDecl *Pattern,
2935                              UsingDecl *Instance,
2936                              ASTContext &C) {
2937  return C.getInstantiatedFromUsingDecl(Instance) == Pattern;
2938}
2939
2940static bool isInstantiationOf(UnresolvedUsingValueDecl *Pattern,
2941                              UsingDecl *Instance,
2942                              ASTContext &C) {
2943  return C.getInstantiatedFromUsingDecl(Instance) == Pattern;
2944}
2945
2946static bool isInstantiationOf(UnresolvedUsingTypenameDecl *Pattern,
2947                              UsingDecl *Instance,
2948                              ASTContext &C) {
2949  return C.getInstantiatedFromUsingDecl(Instance) == Pattern;
2950}
2951
2952static bool isInstantiationOfStaticDataMember(VarDecl *Pattern,
2953                                              VarDecl *Instance) {
2954  assert(Instance->isStaticDataMember());
2955
2956  Pattern = Pattern->getCanonicalDecl();
2957
2958  do {
2959    Instance = Instance->getCanonicalDecl();
2960    if (Pattern == Instance) return true;
2961    Instance = Instance->getInstantiatedFromStaticDataMember();
2962  } while (Instance);
2963
2964  return false;
2965}
2966
2967// Other is the prospective instantiation
2968// D is the prospective pattern
2969static bool isInstantiationOf(ASTContext &Ctx, NamedDecl *D, Decl *Other) {
2970  if (D->getKind() != Other->getKind()) {
2971    if (UnresolvedUsingTypenameDecl *UUD
2972          = dyn_cast<UnresolvedUsingTypenameDecl>(D)) {
2973      if (UsingDecl *UD = dyn_cast<UsingDecl>(Other)) {
2974        return isInstantiationOf(UUD, UD, Ctx);
2975      }
2976    }
2977
2978    if (UnresolvedUsingValueDecl *UUD
2979          = dyn_cast<UnresolvedUsingValueDecl>(D)) {
2980      if (UsingDecl *UD = dyn_cast<UsingDecl>(Other)) {
2981        return isInstantiationOf(UUD, UD, Ctx);
2982      }
2983    }
2984
2985    return false;
2986  }
2987
2988  if (CXXRecordDecl *Record = dyn_cast<CXXRecordDecl>(Other))
2989    return isInstantiationOf(cast<CXXRecordDecl>(D), Record);
2990
2991  if (FunctionDecl *Function = dyn_cast<FunctionDecl>(Other))
2992    return isInstantiationOf(cast<FunctionDecl>(D), Function);
2993
2994  if (EnumDecl *Enum = dyn_cast<EnumDecl>(Other))
2995    return isInstantiationOf(cast<EnumDecl>(D), Enum);
2996
2997  if (VarDecl *Var = dyn_cast<VarDecl>(Other))
2998    if (Var->isStaticDataMember())
2999      return isInstantiationOfStaticDataMember(cast<VarDecl>(D), Var);
3000
3001  if (ClassTemplateDecl *Temp = dyn_cast<ClassTemplateDecl>(Other))
3002    return isInstantiationOf(cast<ClassTemplateDecl>(D), Temp);
3003
3004  if (FunctionTemplateDecl *Temp = dyn_cast<FunctionTemplateDecl>(Other))
3005    return isInstantiationOf(cast<FunctionTemplateDecl>(D), Temp);
3006
3007  if (ClassTemplatePartialSpecializationDecl *PartialSpec
3008        = dyn_cast<ClassTemplatePartialSpecializationDecl>(Other))
3009    return isInstantiationOf(cast<ClassTemplatePartialSpecializationDecl>(D),
3010                             PartialSpec);
3011
3012  if (FieldDecl *Field = dyn_cast<FieldDecl>(Other)) {
3013    if (!Field->getDeclName()) {
3014      // This is an unnamed field.
3015      return Ctx.getInstantiatedFromUnnamedFieldDecl(Field) ==
3016        cast<FieldDecl>(D);
3017    }
3018  }
3019
3020  if (UsingDecl *Using = dyn_cast<UsingDecl>(Other))
3021    return isInstantiationOf(cast<UsingDecl>(D), Using, Ctx);
3022
3023  if (UsingShadowDecl *Shadow = dyn_cast<UsingShadowDecl>(Other))
3024    return isInstantiationOf(cast<UsingShadowDecl>(D), Shadow, Ctx);
3025
3026  return D->getDeclName() && isa<NamedDecl>(Other) &&
3027    D->getDeclName() == cast<NamedDecl>(Other)->getDeclName();
3028}
3029
3030template<typename ForwardIterator>
3031static NamedDecl *findInstantiationOf(ASTContext &Ctx,
3032                                      NamedDecl *D,
3033                                      ForwardIterator first,
3034                                      ForwardIterator last) {
3035  for (; first != last; ++first)
3036    if (isInstantiationOf(Ctx, D, *first))
3037      return cast<NamedDecl>(*first);
3038
3039  return 0;
3040}
3041
3042/// \brief Finds the instantiation of the given declaration context
3043/// within the current instantiation.
3044///
3045/// \returns NULL if there was an error
3046DeclContext *Sema::FindInstantiatedContext(SourceLocation Loc, DeclContext* DC,
3047                          const MultiLevelTemplateArgumentList &TemplateArgs) {
3048  if (NamedDecl *D = dyn_cast<NamedDecl>(DC)) {
3049    Decl* ID = FindInstantiatedDecl(Loc, D, TemplateArgs);
3050    return cast_or_null<DeclContext>(ID);
3051  } else return DC;
3052}
3053
3054/// \brief Find the instantiation of the given declaration within the
3055/// current instantiation.
3056///
3057/// This routine is intended to be used when \p D is a declaration
3058/// referenced from within a template, that needs to mapped into the
3059/// corresponding declaration within an instantiation. For example,
3060/// given:
3061///
3062/// \code
3063/// template<typename T>
3064/// struct X {
3065///   enum Kind {
3066///     KnownValue = sizeof(T)
3067///   };
3068///
3069///   bool getKind() const { return KnownValue; }
3070/// };
3071///
3072/// template struct X<int>;
3073/// \endcode
3074///
3075/// In the instantiation of X<int>::getKind(), we need to map the
3076/// EnumConstantDecl for KnownValue (which refers to
3077/// X<T>::<Kind>::KnownValue) to its instantiation
3078/// (X<int>::<Kind>::KnownValue). InstantiateCurrentDeclRef() performs
3079/// this mapping from within the instantiation of X<int>.
3080NamedDecl *Sema::FindInstantiatedDecl(SourceLocation Loc, NamedDecl *D,
3081                          const MultiLevelTemplateArgumentList &TemplateArgs) {
3082  DeclContext *ParentDC = D->getDeclContext();
3083  if (isa<ParmVarDecl>(D) || isa<NonTypeTemplateParmDecl>(D) ||
3084      isa<TemplateTypeParmDecl>(D) || isa<TemplateTemplateParmDecl>(D) ||
3085      (ParentDC->isFunctionOrMethod() && ParentDC->isDependentContext())) {
3086    // D is a local of some kind. Look into the map of local
3087    // declarations to their instantiations.
3088    typedef LocalInstantiationScope::DeclArgumentPack DeclArgumentPack;
3089    llvm::PointerUnion<Decl *, DeclArgumentPack *> *Found
3090      = CurrentInstantiationScope->findInstantiationOf(D);
3091
3092    if (Found) {
3093      if (Decl *FD = Found->dyn_cast<Decl *>())
3094        return cast<NamedDecl>(FD);
3095
3096      unsigned PackIdx = ArgumentPackSubstitutionIndex;
3097      return cast<NamedDecl>((*Found->get<DeclArgumentPack *>())[PackIdx]);
3098    }
3099
3100    // If we didn't find the decl, then we must have a label decl that hasn't
3101    // been found yet.  Lazily instantiate it and return it now.
3102    assert(isa<LabelDecl>(D));
3103
3104    Decl *Inst = SubstDecl(D, CurContext, TemplateArgs);
3105    assert(Inst && "Failed to instantiate label??");
3106
3107    CurrentInstantiationScope->InstantiatedLocal(D, Inst);
3108    return cast<LabelDecl>(Inst);
3109  }
3110
3111  if (CXXRecordDecl *Record = dyn_cast<CXXRecordDecl>(D)) {
3112    if (!Record->isDependentContext())
3113      return D;
3114
3115    // If the RecordDecl is actually the injected-class-name or a
3116    // "templated" declaration for a class template, class template
3117    // partial specialization, or a member class of a class template,
3118    // substitute into the injected-class-name of the class template
3119    // or partial specialization to find the new DeclContext.
3120    QualType T;
3121    ClassTemplateDecl *ClassTemplate = Record->getDescribedClassTemplate();
3122
3123    if (ClassTemplate) {
3124      T = ClassTemplate->getInjectedClassNameSpecialization();
3125    } else if (ClassTemplatePartialSpecializationDecl *PartialSpec
3126                 = dyn_cast<ClassTemplatePartialSpecializationDecl>(Record)) {
3127      ClassTemplate = PartialSpec->getSpecializedTemplate();
3128
3129      // If we call SubstType with an InjectedClassNameType here we
3130      // can end up in an infinite loop.
3131      T = Context.getTypeDeclType(Record);
3132      assert(isa<InjectedClassNameType>(T) &&
3133             "type of partial specialization is not an InjectedClassNameType");
3134      T = cast<InjectedClassNameType>(T)->getInjectedSpecializationType();
3135    }
3136
3137    if (!T.isNull()) {
3138      // Substitute into the injected-class-name to get the type
3139      // corresponding to the instantiation we want, which may also be
3140      // the current instantiation (if we're in a template
3141      // definition). This substitution should never fail, since we
3142      // know we can instantiate the injected-class-name or we
3143      // wouldn't have gotten to the injected-class-name!
3144
3145      // FIXME: Can we use the CurrentInstantiationScope to avoid this
3146      // extra instantiation in the common case?
3147      T = SubstType(T, TemplateArgs, Loc, DeclarationName());
3148      assert(!T.isNull() && "Instantiation of injected-class-name cannot fail.");
3149
3150      if (!T->isDependentType()) {
3151        assert(T->isRecordType() && "Instantiation must produce a record type");
3152        return T->getAs<RecordType>()->getDecl();
3153      }
3154
3155      // We are performing "partial" template instantiation to create
3156      // the member declarations for the members of a class template
3157      // specialization. Therefore, D is actually referring to something
3158      // in the current instantiation. Look through the current
3159      // context, which contains actual instantiations, to find the
3160      // instantiation of the "current instantiation" that D refers
3161      // to.
3162      bool SawNonDependentContext = false;
3163      for (DeclContext *DC = CurContext; !DC->isFileContext();
3164           DC = DC->getParent()) {
3165        if (ClassTemplateSpecializationDecl *Spec
3166                          = dyn_cast<ClassTemplateSpecializationDecl>(DC))
3167          if (isInstantiationOf(ClassTemplate,
3168                                Spec->getSpecializedTemplate()))
3169            return Spec;
3170
3171        if (!DC->isDependentContext())
3172          SawNonDependentContext = true;
3173      }
3174
3175      // We're performing "instantiation" of a member of the current
3176      // instantiation while we are type-checking the
3177      // definition. Compute the declaration context and return that.
3178      assert(!SawNonDependentContext &&
3179             "No dependent context while instantiating record");
3180      DeclContext *DC = computeDeclContext(T);
3181      assert(DC &&
3182             "Unable to find declaration for the current instantiation");
3183      return cast<CXXRecordDecl>(DC);
3184    }
3185
3186    // Fall through to deal with other dependent record types (e.g.,
3187    // anonymous unions in class templates).
3188  }
3189
3190  if (!ParentDC->isDependentContext())
3191    return D;
3192
3193  ParentDC = FindInstantiatedContext(Loc, ParentDC, TemplateArgs);
3194  if (!ParentDC)
3195    return 0;
3196
3197  if (ParentDC != D->getDeclContext()) {
3198    // We performed some kind of instantiation in the parent context,
3199    // so now we need to look into the instantiated parent context to
3200    // find the instantiation of the declaration D.
3201
3202    // If our context used to be dependent, we may need to instantiate
3203    // it before performing lookup into that context.
3204    bool IsBeingInstantiated = false;
3205    if (CXXRecordDecl *Spec = dyn_cast<CXXRecordDecl>(ParentDC)) {
3206      if (!Spec->isDependentContext()) {
3207        QualType T = Context.getTypeDeclType(Spec);
3208        const RecordType *Tag = T->getAs<RecordType>();
3209        assert(Tag && "type of non-dependent record is not a RecordType");
3210        if (Tag->isBeingDefined())
3211          IsBeingInstantiated = true;
3212        if (!Tag->isBeingDefined() &&
3213            RequireCompleteType(Loc, T, diag::err_incomplete_type))
3214          return 0;
3215
3216        ParentDC = Tag->getDecl();
3217      }
3218    }
3219
3220    NamedDecl *Result = 0;
3221    if (D->getDeclName()) {
3222      DeclContext::lookup_result Found = ParentDC->lookup(D->getDeclName());
3223      Result = findInstantiationOf(Context, D, Found.first, Found.second);
3224    } else {
3225      // Since we don't have a name for the entity we're looking for,
3226      // our only option is to walk through all of the declarations to
3227      // find that name. This will occur in a few cases:
3228      //
3229      //   - anonymous struct/union within a template
3230      //   - unnamed class/struct/union/enum within a template
3231      //
3232      // FIXME: Find a better way to find these instantiations!
3233      Result = findInstantiationOf(Context, D,
3234                                   ParentDC->decls_begin(),
3235                                   ParentDC->decls_end());
3236    }
3237
3238    if (!Result) {
3239      if (isa<UsingShadowDecl>(D)) {
3240        // UsingShadowDecls can instantiate to nothing because of using hiding.
3241      } else if (Diags.hasErrorOccurred()) {
3242        // We've already complained about something, so most likely this
3243        // declaration failed to instantiate. There's no point in complaining
3244        // further, since this is normal in invalid code.
3245      } else if (IsBeingInstantiated) {
3246        // The class in which this member exists is currently being
3247        // instantiated, and we haven't gotten around to instantiating this
3248        // member yet. This can happen when the code uses forward declarations
3249        // of member classes, and introduces ordering dependencies via
3250        // template instantiation.
3251        Diag(Loc, diag::err_member_not_yet_instantiated)
3252          << D->getDeclName()
3253          << Context.getTypeDeclType(cast<CXXRecordDecl>(ParentDC));
3254        Diag(D->getLocation(), diag::note_non_instantiated_member_here);
3255      } else {
3256        // We should have found something, but didn't.
3257        llvm_unreachable("Unable to find instantiation of declaration!");
3258      }
3259    }
3260
3261    D = Result;
3262  }
3263
3264  return D;
3265}
3266
3267/// \brief Performs template instantiation for all implicit template
3268/// instantiations we have seen until this point.
3269void Sema::PerformPendingInstantiations(bool LocalOnly) {
3270  // Load pending instantiations from the external source.
3271  if (!LocalOnly && ExternalSource) {
3272    SmallVector<std::pair<ValueDecl *, SourceLocation>, 4> Pending;
3273    ExternalSource->ReadPendingInstantiations(Pending);
3274    PendingInstantiations.insert(PendingInstantiations.begin(),
3275                                 Pending.begin(), Pending.end());
3276  }
3277
3278  while (!PendingLocalImplicitInstantiations.empty() ||
3279         (!LocalOnly && !PendingInstantiations.empty())) {
3280    PendingImplicitInstantiation Inst;
3281
3282    if (PendingLocalImplicitInstantiations.empty()) {
3283      Inst = PendingInstantiations.front();
3284      PendingInstantiations.pop_front();
3285    } else {
3286      Inst = PendingLocalImplicitInstantiations.front();
3287      PendingLocalImplicitInstantiations.pop_front();
3288    }
3289
3290    // Instantiate function definitions
3291    if (FunctionDecl *Function = dyn_cast<FunctionDecl>(Inst.first)) {
3292      PrettyDeclStackTraceEntry CrashInfo(*this, Function, SourceLocation(),
3293                                          "instantiating function definition");
3294      bool DefinitionRequired = Function->getTemplateSpecializationKind() ==
3295                                TSK_ExplicitInstantiationDefinition;
3296      InstantiateFunctionDefinition(/*FIXME:*/Inst.second, Function, true,
3297                                    DefinitionRequired);
3298      continue;
3299    }
3300
3301    // Instantiate static data member definitions.
3302    VarDecl *Var = cast<VarDecl>(Inst.first);
3303    assert(Var->isStaticDataMember() && "Not a static data member?");
3304
3305    // Don't try to instantiate declarations if the most recent redeclaration
3306    // is invalid.
3307    if (Var->getMostRecentDeclaration()->isInvalidDecl())
3308      continue;
3309
3310    // Check if the most recent declaration has changed the specialization kind
3311    // and removed the need for implicit instantiation.
3312    switch (Var->getMostRecentDeclaration()->getTemplateSpecializationKind()) {
3313    case TSK_Undeclared:
3314      assert(false && "Cannot instantitiate an undeclared specialization.");
3315    case TSK_ExplicitInstantiationDeclaration:
3316    case TSK_ExplicitSpecialization:
3317      continue;  // No longer need to instantiate this type.
3318    case TSK_ExplicitInstantiationDefinition:
3319      // We only need an instantiation if the pending instantiation *is* the
3320      // explicit instantiation.
3321      if (Var != Var->getMostRecentDeclaration()) continue;
3322    case TSK_ImplicitInstantiation:
3323      break;
3324    }
3325
3326    PrettyDeclStackTraceEntry CrashInfo(*this, Var, Var->getLocation(),
3327                                        "instantiating static data member "
3328                                        "definition");
3329
3330    bool DefinitionRequired = Var->getTemplateSpecializationKind() ==
3331                              TSK_ExplicitInstantiationDefinition;
3332    InstantiateStaticDataMemberDefinition(/*FIXME:*/Inst.second, Var, true,
3333                                          DefinitionRequired);
3334  }
3335}
3336
3337void Sema::PerformDependentDiagnostics(const DeclContext *Pattern,
3338                       const MultiLevelTemplateArgumentList &TemplateArgs) {
3339  for (DeclContext::ddiag_iterator I = Pattern->ddiag_begin(),
3340         E = Pattern->ddiag_end(); I != E; ++I) {
3341    DependentDiagnostic *DD = *I;
3342
3343    switch (DD->getKind()) {
3344    case DependentDiagnostic::Access:
3345      HandleDependentAccessCheck(*DD, TemplateArgs);
3346      break;
3347    }
3348  }
3349}
3350