SemaTemplateInstantiateDecl.cpp revision e3499cae8e5323ac553ad56977bf1cd42b9a5a35 
1//===--- SemaTemplateInstantiateDecl.cpp - C++ Template Decl Instantiation ===/
2//
3//                     The LLVM Compiler Infrastructure
4//
5// This file is distributed under the University of Illinois Open Source
6// License. See LICENSE.TXT for details.
7//===----------------------------------------------------------------------===/
8//
9//  This file implements C++ template instantiation for declarations.
10//
11//===----------------------------------------------------------------------===/
12#include "clang/Sema/SemaInternal.h"
13#include "clang/Sema/Lookup.h"
14#include "clang/Sema/PrettyDeclStackTrace.h"
15#include "clang/Sema/Template.h"
16#include "clang/AST/ASTConsumer.h"
17#include "clang/AST/ASTContext.h"
18#include "clang/AST/DeclTemplate.h"
19#include "clang/AST/DeclVisitor.h"
20#include "clang/AST/DependentDiagnostic.h"
21#include "clang/AST/Expr.h"
22#include "clang/AST/ExprCXX.h"
23#include "clang/AST/TypeLoc.h"
24#include "clang/Lex/Preprocessor.h"
25
26using namespace clang;
27
28bool TemplateDeclInstantiator::SubstQualifier(const DeclaratorDecl *OldDecl,
29                                              DeclaratorDecl *NewDecl) {
30  if (!OldDecl->getQualifierLoc())
31    return false;
32
33  NestedNameSpecifierLoc NewQualifierLoc
34    = SemaRef.SubstNestedNameSpecifierLoc(OldDecl->getQualifierLoc(),
35                                          TemplateArgs);
36
37  if (!NewQualifierLoc)
38    return true;
39
40  NewDecl->setQualifierInfo(NewQualifierLoc);
41  return false;
42}
43
44bool TemplateDeclInstantiator::SubstQualifier(const TagDecl *OldDecl,
45                                              TagDecl *NewDecl) {
46  if (!OldDecl->getQualifierLoc())
47    return false;
48
49  NestedNameSpecifierLoc NewQualifierLoc
50  = SemaRef.SubstNestedNameSpecifierLoc(OldDecl->getQualifierLoc(),
51                                        TemplateArgs);
52
53  if (!NewQualifierLoc)
54    return true;
55
56  NewDecl->setQualifierInfo(NewQualifierLoc);
57  return false;
58}
59
60// FIXME: Is this still too simple?
61void Sema::InstantiateAttrs(const MultiLevelTemplateArgumentList &TemplateArgs,
62                            Decl *Tmpl, Decl *New) {
63  for (AttrVec::const_iterator i = Tmpl->attr_begin(), e = Tmpl->attr_end();
64       i != e; ++i) {
65    const Attr *TmplAttr = *i;
66    // FIXME: This should be generalized to more than just the AlignedAttr.
67    if (const AlignedAttr *Aligned = dyn_cast<AlignedAttr>(TmplAttr)) {
68      if (Aligned->isAlignmentDependent()) {
69        // The alignment expression is not potentially evaluated.
70        EnterExpressionEvaluationContext Unevaluated(*this,
71                                                     Sema::Unevaluated);
72
73        if (Aligned->isAlignmentExpr()) {
74          ExprResult Result = SubstExpr(Aligned->getAlignmentExpr(),
75                                        TemplateArgs);
76          if (!Result.isInvalid())
77            AddAlignedAttr(Aligned->getLocation(), New, Result.takeAs<Expr>());
78        }
79        else {
80          TypeSourceInfo *Result = SubstType(Aligned->getAlignmentType(),
81                                             TemplateArgs,
82                                             Aligned->getLocation(),
83                                             DeclarationName());
84          if (Result)
85            AddAlignedAttr(Aligned->getLocation(), New, Result);
86        }
87        continue;
88      }
89    }
90
91    // FIXME: Is cloning correct for all attributes?
92    Attr *NewAttr = TmplAttr->clone(Context);
93    New->addAttr(NewAttr);
94  }
95}
96
97Decl *
98TemplateDeclInstantiator::VisitTranslationUnitDecl(TranslationUnitDecl *D) {
99  assert(false && "Translation units cannot be instantiated");
100  return D;
101}
102
103Decl *
104TemplateDeclInstantiator::VisitLabelDecl(LabelDecl *D) {
105  LabelDecl *Inst = LabelDecl::Create(SemaRef.Context, Owner, D->getLocation(),
106                                      D->getIdentifier());
107  Owner->addDecl(Inst);
108  return Inst;
109}
110
111Decl *
112TemplateDeclInstantiator::VisitNamespaceDecl(NamespaceDecl *D) {
113  assert(false && "Namespaces cannot be instantiated");
114  return D;
115}
116
117Decl *
118TemplateDeclInstantiator::VisitNamespaceAliasDecl(NamespaceAliasDecl *D) {
119  NamespaceAliasDecl *Inst
120    = NamespaceAliasDecl::Create(SemaRef.Context, Owner,
121                                 D->getNamespaceLoc(),
122                                 D->getAliasLoc(),
123                                 D->getIdentifier(),
124                                 D->getQualifierLoc(),
125                                 D->getTargetNameLoc(),
126                                 D->getNamespace());
127  Owner->addDecl(Inst);
128  return Inst;
129}
130
131Decl *TemplateDeclInstantiator::InstantiateTypedefNameDecl(TypedefNameDecl *D,
132                                                           bool IsTypeAlias) {
133  bool Invalid = false;
134  TypeSourceInfo *DI = D->getTypeSourceInfo();
135  if (DI->getType()->isDependentType() ||
136      DI->getType()->isVariablyModifiedType()) {
137    DI = SemaRef.SubstType(DI, TemplateArgs,
138                           D->getLocation(), D->getDeclName());
139    if (!DI) {
140      Invalid = true;
141      DI = SemaRef.Context.getTrivialTypeSourceInfo(SemaRef.Context.IntTy);
142    }
143  } else {
144    SemaRef.MarkDeclarationsReferencedInType(D->getLocation(), DI->getType());
145  }
146
147  // Create the new typedef
148  TypedefNameDecl *Typedef;
149  if (IsTypeAlias)
150    Typedef = TypeAliasDecl::Create(SemaRef.Context, Owner, D->getLocStart(),
151                                    D->getLocation(), D->getIdentifier(), DI);
152  else
153    Typedef = TypedefDecl::Create(SemaRef.Context, Owner, D->getLocStart(),
154                                  D->getLocation(), D->getIdentifier(), DI);
155  if (Invalid)
156    Typedef->setInvalidDecl();
157
158  // If the old typedef was the name for linkage purposes of an anonymous
159  // tag decl, re-establish that relationship for the new typedef.
160  if (const TagType *oldTagType = D->getUnderlyingType()->getAs<TagType>()) {
161    TagDecl *oldTag = oldTagType->getDecl();
162    if (oldTag->getTypedefNameForAnonDecl() == D) {
163      TagDecl *newTag = DI->getType()->castAs<TagType>()->getDecl();
164      assert(!newTag->getIdentifier() && !newTag->getTypedefNameForAnonDecl());
165      newTag->setTypedefNameForAnonDecl(Typedef);
166    }
167  }
168
169  if (TypedefNameDecl *Prev = D->getPreviousDeclaration()) {
170    NamedDecl *InstPrev = SemaRef.FindInstantiatedDecl(D->getLocation(), Prev,
171                                                       TemplateArgs);
172    if (!InstPrev)
173      return 0;
174
175    Typedef->setPreviousDeclaration(cast<TypedefNameDecl>(InstPrev));
176  }
177
178  SemaRef.InstantiateAttrs(TemplateArgs, D, Typedef);
179
180  Typedef->setAccess(D->getAccess());
181
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 S The semantic analysis object.
243///
244/// \param Init The initializer to instantiate.
245///
246/// \param TemplateArgs Template arguments to be substituted into the
247/// initializer.
248///
249/// \param NewArgs Will be filled in with the instantiation arguments.
250///
251/// \returns true if an error occurred, false otherwise
252static bool InstantiateInitializer(Sema &S, Expr *Init,
253                            const MultiLevelTemplateArgumentList &TemplateArgs,
254                                   SourceLocation &LParenLoc,
255                                   ASTOwningVector<Expr*> &NewArgs,
256                                   SourceLocation &RParenLoc) {
257  NewArgs.clear();
258  LParenLoc = SourceLocation();
259  RParenLoc = SourceLocation();
260
261  if (!Init)
262    return false;
263
264  if (ExprWithCleanups *ExprTemp = dyn_cast<ExprWithCleanups>(Init))
265    Init = ExprTemp->getSubExpr();
266
267  while (CXXBindTemporaryExpr *Binder = dyn_cast<CXXBindTemporaryExpr>(Init))
268    Init = Binder->getSubExpr();
269
270  if (ImplicitCastExpr *ICE = dyn_cast<ImplicitCastExpr>(Init))
271    Init = ICE->getSubExprAsWritten();
272
273  if (ParenListExpr *ParenList = dyn_cast<ParenListExpr>(Init)) {
274    LParenLoc = ParenList->getLParenLoc();
275    RParenLoc = ParenList->getRParenLoc();
276    return S.SubstExprs(ParenList->getExprs(), ParenList->getNumExprs(),
277                        true, TemplateArgs, NewArgs);
278  }
279
280  if (CXXConstructExpr *Construct = dyn_cast<CXXConstructExpr>(Init)) {
281    if (!isa<CXXTemporaryObjectExpr>(Construct)) {
282      if (S.SubstExprs(Construct->getArgs(), Construct->getNumArgs(), true,
283                       TemplateArgs, NewArgs))
284        return true;
285
286      // FIXME: Fake locations!
287      LParenLoc = S.PP.getLocForEndOfToken(Init->getLocStart());
288      RParenLoc = LParenLoc;
289      return false;
290    }
291  }
292
293  ExprResult Result = S.SubstExpr(Init, TemplateArgs);
294  if (Result.isInvalid())
295    return true;
296
297  NewArgs.push_back(Result.takeAs<Expr>());
298  return false;
299}
300
301Decl *TemplateDeclInstantiator::VisitVarDecl(VarDecl *D) {
302  // If this is the variable for an anonymous struct or union,
303  // instantiate the anonymous struct/union type first.
304  if (const RecordType *RecordTy = D->getType()->getAs<RecordType>())
305    if (RecordTy->getDecl()->isAnonymousStructOrUnion())
306      if (!VisitCXXRecordDecl(cast<CXXRecordDecl>(RecordTy->getDecl())))
307        return 0;
308
309  // Do substitution on the type of the declaration
310  TypeSourceInfo *DI = SemaRef.SubstType(D->getTypeSourceInfo(),
311                                         TemplateArgs,
312                                         D->getTypeSpecStartLoc(),
313                                         D->getDeclName());
314  if (!DI)
315    return 0;
316
317  if (DI->getType()->isFunctionType()) {
318    SemaRef.Diag(D->getLocation(), diag::err_variable_instantiates_to_function)
319      << D->isStaticDataMember() << DI->getType();
320    return 0;
321  }
322
323  // Build the instantiated declaration
324  VarDecl *Var = VarDecl::Create(SemaRef.Context, Owner,
325                                 D->getInnerLocStart(),
326                                 D->getLocation(), D->getIdentifier(),
327                                 DI->getType(), DI,
328                                 D->getStorageClass(),
329                                 D->getStorageClassAsWritten());
330  Var->setThreadSpecified(D->isThreadSpecified());
331  Var->setCXXDirectInitializer(D->hasCXXDirectInitializer());
332  Var->setCXXForRangeDecl(D->isCXXForRangeDecl());
333
334  // Substitute the nested name specifier, if any.
335  if (SubstQualifier(D, Var))
336    return 0;
337
338  // If we are instantiating a static data member defined
339  // out-of-line, the instantiation will have the same lexical
340  // context (which will be a namespace scope) as the template.
341  if (D->isOutOfLine())
342    Var->setLexicalDeclContext(D->getLexicalDeclContext());
343
344  Var->setAccess(D->getAccess());
345
346  if (!D->isStaticDataMember()) {
347    Var->setUsed(D->isUsed(false));
348    Var->setReferenced(D->isReferenced());
349  }
350
351  // FIXME: In theory, we could have a previous declaration for variables that
352  // are not static data members.
353  bool Redeclaration = false;
354  // FIXME: having to fake up a LookupResult is dumb.
355  LookupResult Previous(SemaRef, Var->getDeclName(), Var->getLocation(),
356                        Sema::LookupOrdinaryName, Sema::ForRedeclaration);
357  if (D->isStaticDataMember())
358    SemaRef.LookupQualifiedName(Previous, Owner, false);
359  SemaRef.CheckVariableDeclaration(Var, Previous, Redeclaration);
360
361  if (D->isOutOfLine()) {
362    if (!D->isStaticDataMember())
363      D->getLexicalDeclContext()->addDecl(Var);
364    Owner->makeDeclVisibleInContext(Var);
365  } else {
366    Owner->addDecl(Var);
367    if (Owner->isFunctionOrMethod())
368      SemaRef.CurrentInstantiationScope->InstantiatedLocal(D, Var);
369  }
370  SemaRef.InstantiateAttrs(TemplateArgs, D, Var);
371
372  // Link instantiations of static data members back to the template from
373  // which they were instantiated.
374  if (Var->isStaticDataMember())
375    SemaRef.Context.setInstantiatedFromStaticDataMember(Var, D,
376                                                     TSK_ImplicitInstantiation);
377
378  if (Var->getAnyInitializer()) {
379    // We already have an initializer in the class.
380  } else if (D->getInit()) {
381    if (Var->isStaticDataMember() && !D->isOutOfLine())
382      SemaRef.PushExpressionEvaluationContext(Sema::Unevaluated);
383    else
384      SemaRef.PushExpressionEvaluationContext(Sema::PotentiallyEvaluated);
385
386    // Instantiate the initializer.
387    SourceLocation LParenLoc, RParenLoc;
388    ASTOwningVector<Expr*> InitArgs(SemaRef);
389    if (!InstantiateInitializer(SemaRef, D->getInit(), TemplateArgs, LParenLoc,
390                                InitArgs, RParenLoc)) {
391      bool TypeMayContainAuto = true;
392      // Attach the initializer to the declaration, if we have one.
393      if (InitArgs.size() == 0)
394        SemaRef.ActOnUninitializedDecl(Var, TypeMayContainAuto);
395      else if (D->hasCXXDirectInitializer()) {
396        // Add the direct initializer to the declaration.
397        SemaRef.AddCXXDirectInitializerToDecl(Var,
398                                              LParenLoc,
399                                              move_arg(InitArgs),
400                                              RParenLoc,
401                                              TypeMayContainAuto);
402      } else {
403        assert(InitArgs.size() == 1);
404        Expr *Init = InitArgs.take()[0];
405        SemaRef.AddInitializerToDecl(Var, Init, false, TypeMayContainAuto);
406      }
407    } else {
408      // FIXME: Not too happy about invalidating the declaration
409      // because of a bogus initializer.
410      Var->setInvalidDecl();
411    }
412
413    SemaRef.PopExpressionEvaluationContext();
414  } else if ((!Var->isStaticDataMember() || Var->isOutOfLine()) &&
415             !Var->isCXXForRangeDecl())
416    SemaRef.ActOnUninitializedDecl(Var, false);
417
418  // Diagnose unused local variables with dependent types, where the diagnostic
419  // will have been deferred.
420  if (!Var->isInvalidDecl() && Owner->isFunctionOrMethod() && !Var->isUsed() &&
421      D->getType()->isDependentType())
422    SemaRef.DiagnoseUnusedDecl(Var);
423
424  return Var;
425}
426
427Decl *TemplateDeclInstantiator::VisitAccessSpecDecl(AccessSpecDecl *D) {
428  AccessSpecDecl* AD
429    = AccessSpecDecl::Create(SemaRef.Context, D->getAccess(), Owner,
430                             D->getAccessSpecifierLoc(), D->getColonLoc());
431  Owner->addHiddenDecl(AD);
432  return AD;
433}
434
435Decl *TemplateDeclInstantiator::VisitFieldDecl(FieldDecl *D) {
436  bool Invalid = false;
437  TypeSourceInfo *DI = D->getTypeSourceInfo();
438  if (DI->getType()->isDependentType() ||
439      DI->getType()->isVariablyModifiedType())  {
440    DI = SemaRef.SubstType(DI, TemplateArgs,
441                           D->getLocation(), D->getDeclName());
442    if (!DI) {
443      DI = D->getTypeSourceInfo();
444      Invalid = true;
445    } else if (DI->getType()->isFunctionType()) {
446      // C++ [temp.arg.type]p3:
447      //   If a declaration acquires a function type through a type
448      //   dependent on a template-parameter and this causes a
449      //   declaration that does not use the syntactic form of a
450      //   function declarator to have function type, the program is
451      //   ill-formed.
452      SemaRef.Diag(D->getLocation(), diag::err_field_instantiates_to_function)
453        << DI->getType();
454      Invalid = true;
455    }
456  } else {
457    SemaRef.MarkDeclarationsReferencedInType(D->getLocation(), DI->getType());
458  }
459
460  Expr *BitWidth = D->getBitWidth();
461  if (Invalid)
462    BitWidth = 0;
463  else if (BitWidth) {
464    // The bit-width expression is not potentially evaluated.
465    EnterExpressionEvaluationContext Unevaluated(SemaRef, Sema::Unevaluated);
466
467    ExprResult InstantiatedBitWidth
468      = SemaRef.SubstExpr(BitWidth, TemplateArgs);
469    if (InstantiatedBitWidth.isInvalid()) {
470      Invalid = true;
471      BitWidth = 0;
472    } else
473      BitWidth = InstantiatedBitWidth.takeAs<Expr>();
474  }
475
476  FieldDecl *Field = SemaRef.CheckFieldDecl(D->getDeclName(),
477                                            DI->getType(), DI,
478                                            cast<RecordDecl>(Owner),
479                                            D->getLocation(),
480                                            D->isMutable(),
481                                            BitWidth,
482                                            D->hasInClassInitializer(),
483                                            D->getTypeSpecStartLoc(),
484                                            D->getAccess(),
485                                            0);
486  if (!Field) {
487    cast<Decl>(Owner)->setInvalidDecl();
488    return 0;
489  }
490
491  SemaRef.InstantiateAttrs(TemplateArgs, D, Field);
492
493  if (Invalid)
494    Field->setInvalidDecl();
495
496  if (!Field->getDeclName()) {
497    // Keep track of where this decl came from.
498    SemaRef.Context.setInstantiatedFromUnnamedFieldDecl(Field, D);
499  }
500  if (CXXRecordDecl *Parent= dyn_cast<CXXRecordDecl>(Field->getDeclContext())) {
501    if (Parent->isAnonymousStructOrUnion() &&
502        Parent->getRedeclContext()->isFunctionOrMethod())
503      SemaRef.CurrentInstantiationScope->InstantiatedLocal(D, Field);
504  }
505
506  Field->setImplicit(D->isImplicit());
507  Field->setAccess(D->getAccess());
508  Owner->addDecl(Field);
509
510  return Field;
511}
512
513Decl *TemplateDeclInstantiator::VisitIndirectFieldDecl(IndirectFieldDecl *D) {
514  NamedDecl **NamedChain =
515    new (SemaRef.Context)NamedDecl*[D->getChainingSize()];
516
517  int i = 0;
518  for (IndirectFieldDecl::chain_iterator PI =
519       D->chain_begin(), PE = D->chain_end();
520       PI != PE; ++PI) {
521    NamedDecl *Next = SemaRef.FindInstantiatedDecl(D->getLocation(), *PI,
522                                              TemplateArgs);
523    if (!Next)
524      return 0;
525
526    NamedChain[i++] = Next;
527  }
528
529  QualType T = cast<FieldDecl>(NamedChain[i-1])->getType();
530  IndirectFieldDecl* IndirectField
531    = IndirectFieldDecl::Create(SemaRef.Context, Owner, D->getLocation(),
532                                D->getIdentifier(), T,
533                                NamedChain, D->getChainingSize());
534
535
536  IndirectField->setImplicit(D->isImplicit());
537  IndirectField->setAccess(D->getAccess());
538  Owner->addDecl(IndirectField);
539  return IndirectField;
540}
541
542Decl *TemplateDeclInstantiator::VisitFriendDecl(FriendDecl *D) {
543  // Handle friend type expressions by simply substituting template
544  // parameters into the pattern type and checking the result.
545  if (TypeSourceInfo *Ty = D->getFriendType()) {
546    TypeSourceInfo *InstTy;
547    // If this is an unsupported friend, don't bother substituting template
548    // arguments into it. The actual type referred to won't be used by any
549    // parts of Clang, and may not be valid for instantiating. Just use the
550    // same info for the instantiated friend.
551    if (D->isUnsupportedFriend()) {
552      InstTy = Ty;
553    } else {
554      InstTy = SemaRef.SubstType(Ty, TemplateArgs,
555                                 D->getLocation(), DeclarationName());
556    }
557    if (!InstTy)
558      return 0;
559
560    FriendDecl *FD = SemaRef.CheckFriendTypeDecl(D->getFriendLoc(), InstTy);
561    if (!FD)
562      return 0;
563
564    FD->setAccess(AS_public);
565    FD->setUnsupportedFriend(D->isUnsupportedFriend());
566    Owner->addDecl(FD);
567    return FD;
568  }
569
570  NamedDecl *ND = D->getFriendDecl();
571  assert(ND && "friend decl must be a decl or a type!");
572
573  // All of the Visit implementations for the various potential friend
574  // declarations have to be carefully written to work for friend
575  // objects, with the most important detail being that the target
576  // decl should almost certainly not be placed in Owner.
577  Decl *NewND = Visit(ND);
578  if (!NewND) return 0;
579
580  FriendDecl *FD =
581    FriendDecl::Create(SemaRef.Context, Owner, D->getLocation(),
582                       cast<NamedDecl>(NewND), D->getFriendLoc());
583  FD->setAccess(AS_public);
584  FD->setUnsupportedFriend(D->isUnsupportedFriend());
585  Owner->addDecl(FD);
586  return FD;
587}
588
589Decl *TemplateDeclInstantiator::VisitStaticAssertDecl(StaticAssertDecl *D) {
590  Expr *AssertExpr = D->getAssertExpr();
591
592  // The expression in a static assertion is not potentially evaluated.
593  EnterExpressionEvaluationContext Unevaluated(SemaRef, Sema::Unevaluated);
594
595  ExprResult InstantiatedAssertExpr
596    = SemaRef.SubstExpr(AssertExpr, TemplateArgs);
597  if (InstantiatedAssertExpr.isInvalid())
598    return 0;
599
600  ExprResult Message(D->getMessage());
601  D->getMessage();
602  return SemaRef.ActOnStaticAssertDeclaration(D->getLocation(),
603                                              InstantiatedAssertExpr.get(),
604                                              Message.get(),
605                                              D->getRParenLoc());
606}
607
608Decl *TemplateDeclInstantiator::VisitEnumDecl(EnumDecl *D) {
609  EnumDecl *Enum = EnumDecl::Create(SemaRef.Context, Owner, D->getLocStart(),
610                                    D->getLocation(), D->getIdentifier(),
611                                    /*PrevDecl=*/0, D->isScoped(),
612                                    D->isScopedUsingClassTag(), D->isFixed());
613  if (D->isFixed()) {
614    if (TypeSourceInfo* TI = D->getIntegerTypeSourceInfo()) {
615      // If we have type source information for the underlying type, it means it
616      // has been explicitly set by the user. Perform substitution on it before
617      // moving on.
618      SourceLocation UnderlyingLoc = TI->getTypeLoc().getBeginLoc();
619      Enum->setIntegerTypeSourceInfo(SemaRef.SubstType(TI,
620                                                       TemplateArgs,
621                                                       UnderlyingLoc,
622                                                       DeclarationName()));
623
624      if (!Enum->getIntegerTypeSourceInfo())
625        Enum->setIntegerType(SemaRef.Context.IntTy);
626    }
627    else {
628      assert(!D->getIntegerType()->isDependentType()
629             && "Dependent type without type source info");
630      Enum->setIntegerType(D->getIntegerType());
631    }
632  }
633
634  SemaRef.InstantiateAttrs(TemplateArgs, D, Enum);
635
636  Enum->setInstantiationOfMemberEnum(D);
637  Enum->setAccess(D->getAccess());
638  if (SubstQualifier(D, Enum)) return 0;
639  Owner->addDecl(Enum);
640  Enum->startDefinition();
641
642  if (D->getDeclContext()->isFunctionOrMethod())
643    SemaRef.CurrentInstantiationScope->InstantiatedLocal(D, Enum);
644
645  llvm::SmallVector<Decl*, 4> Enumerators;
646
647  EnumConstantDecl *LastEnumConst = 0;
648  for (EnumDecl::enumerator_iterator EC = D->enumerator_begin(),
649         ECEnd = D->enumerator_end();
650       EC != ECEnd; ++EC) {
651    // The specified value for the enumerator.
652    ExprResult Value = SemaRef.Owned((Expr *)0);
653    if (Expr *UninstValue = EC->getInitExpr()) {
654      // The enumerator's value expression is not potentially evaluated.
655      EnterExpressionEvaluationContext Unevaluated(SemaRef,
656                                                   Sema::Unevaluated);
657
658      Value = SemaRef.SubstExpr(UninstValue, TemplateArgs);
659    }
660
661    // Drop the initial value and continue.
662    bool isInvalid = false;
663    if (Value.isInvalid()) {
664      Value = SemaRef.Owned((Expr *)0);
665      isInvalid = true;
666    }
667
668    EnumConstantDecl *EnumConst
669      = SemaRef.CheckEnumConstant(Enum, LastEnumConst,
670                                  EC->getLocation(), EC->getIdentifier(),
671                                  Value.get());
672
673    if (isInvalid) {
674      if (EnumConst)
675        EnumConst->setInvalidDecl();
676      Enum->setInvalidDecl();
677    }
678
679    if (EnumConst) {
680      SemaRef.InstantiateAttrs(TemplateArgs, *EC, EnumConst);
681
682      EnumConst->setAccess(Enum->getAccess());
683      Enum->addDecl(EnumConst);
684      Enumerators.push_back(EnumConst);
685      LastEnumConst = EnumConst;
686
687      if (D->getDeclContext()->isFunctionOrMethod()) {
688        // If the enumeration is within a function or method, record the enum
689        // constant as a local.
690        SemaRef.CurrentInstantiationScope->InstantiatedLocal(*EC, EnumConst);
691      }
692    }
693  }
694
695  // FIXME: Fixup LBraceLoc and RBraceLoc
696  // FIXME: Empty Scope and AttributeList (required to handle attribute packed).
697  SemaRef.ActOnEnumBody(Enum->getLocation(), SourceLocation(), SourceLocation(),
698                        Enum,
699                        Enumerators.data(), Enumerators.size(),
700                        0, 0);
701
702  return Enum;
703}
704
705Decl *TemplateDeclInstantiator::VisitEnumConstantDecl(EnumConstantDecl *D) {
706  assert(false && "EnumConstantDecls can only occur within EnumDecls.");
707  return 0;
708}
709
710Decl *TemplateDeclInstantiator::VisitClassTemplateDecl(ClassTemplateDecl *D) {
711  bool isFriend = (D->getFriendObjectKind() != Decl::FOK_None);
712
713  // Create a local instantiation scope for this class template, which
714  // will contain the instantiations of the template parameters.
715  LocalInstantiationScope Scope(SemaRef);
716  TemplateParameterList *TempParams = D->getTemplateParameters();
717  TemplateParameterList *InstParams = SubstTemplateParams(TempParams);
718  if (!InstParams)
719    return NULL;
720
721  CXXRecordDecl *Pattern = D->getTemplatedDecl();
722
723  // Instantiate the qualifier.  We have to do this first in case
724  // we're a friend declaration, because if we are then we need to put
725  // the new declaration in the appropriate context.
726  NestedNameSpecifierLoc QualifierLoc = Pattern->getQualifierLoc();
727  if (QualifierLoc) {
728    QualifierLoc = SemaRef.SubstNestedNameSpecifierLoc(QualifierLoc,
729                                                       TemplateArgs);
730    if (!QualifierLoc)
731      return 0;
732  }
733
734  CXXRecordDecl *PrevDecl = 0;
735  ClassTemplateDecl *PrevClassTemplate = 0;
736
737  if (!isFriend && Pattern->getPreviousDeclaration()) {
738    DeclContext::lookup_result Found = Owner->lookup(Pattern->getDeclName());
739    if (Found.first != Found.second) {
740      PrevClassTemplate = dyn_cast<ClassTemplateDecl>(*Found.first);
741      if (PrevClassTemplate)
742        PrevDecl = PrevClassTemplate->getTemplatedDecl();
743    }
744  }
745
746  // If this isn't a friend, then it's a member template, in which
747  // case we just want to build the instantiation in the
748  // specialization.  If it is a friend, we want to build it in
749  // the appropriate context.
750  DeclContext *DC = Owner;
751  if (isFriend) {
752    if (QualifierLoc) {
753      CXXScopeSpec SS;
754      SS.Adopt(QualifierLoc);
755      DC = SemaRef.computeDeclContext(SS);
756      if (!DC) return 0;
757    } else {
758      DC = SemaRef.FindInstantiatedContext(Pattern->getLocation(),
759                                           Pattern->getDeclContext(),
760                                           TemplateArgs);
761    }
762
763    // Look for a previous declaration of the template in the owning
764    // context.
765    LookupResult R(SemaRef, Pattern->getDeclName(), Pattern->getLocation(),
766                   Sema::LookupOrdinaryName, Sema::ForRedeclaration);
767    SemaRef.LookupQualifiedName(R, DC);
768
769    if (R.isSingleResult()) {
770      PrevClassTemplate = R.getAsSingle<ClassTemplateDecl>();
771      if (PrevClassTemplate)
772        PrevDecl = PrevClassTemplate->getTemplatedDecl();
773    }
774
775    if (!PrevClassTemplate && QualifierLoc) {
776      SemaRef.Diag(Pattern->getLocation(), diag::err_not_tag_in_scope)
777        << D->getTemplatedDecl()->getTagKind() << Pattern->getDeclName() << DC
778        << QualifierLoc.getSourceRange();
779      return 0;
780    }
781
782    bool AdoptedPreviousTemplateParams = false;
783    if (PrevClassTemplate) {
784      bool Complain = true;
785
786      // HACK: libstdc++ 4.2.1 contains an ill-formed friend class
787      // template for struct std::tr1::__detail::_Map_base, where the
788      // template parameters of the friend declaration don't match the
789      // template parameters of the original declaration. In this one
790      // case, we don't complain about the ill-formed friend
791      // declaration.
792      if (isFriend && Pattern->getIdentifier() &&
793          Pattern->getIdentifier()->isStr("_Map_base") &&
794          DC->isNamespace() &&
795          cast<NamespaceDecl>(DC)->getIdentifier() &&
796          cast<NamespaceDecl>(DC)->getIdentifier()->isStr("__detail")) {
797        DeclContext *DCParent = DC->getParent();
798        if (DCParent->isNamespace() &&
799            cast<NamespaceDecl>(DCParent)->getIdentifier() &&
800            cast<NamespaceDecl>(DCParent)->getIdentifier()->isStr("tr1")) {
801          DeclContext *DCParent2 = DCParent->getParent();
802          if (DCParent2->isNamespace() &&
803              cast<NamespaceDecl>(DCParent2)->getIdentifier() &&
804              cast<NamespaceDecl>(DCParent2)->getIdentifier()->isStr("std") &&
805              DCParent2->getParent()->isTranslationUnit())
806            Complain = false;
807        }
808      }
809
810      TemplateParameterList *PrevParams
811        = PrevClassTemplate->getTemplateParameters();
812
813      // Make sure the parameter lists match.
814      if (!SemaRef.TemplateParameterListsAreEqual(InstParams, PrevParams,
815                                                  Complain,
816                                                  Sema::TPL_TemplateMatch)) {
817        if (Complain)
818          return 0;
819
820        AdoptedPreviousTemplateParams = true;
821        InstParams = PrevParams;
822      }
823
824      // Do some additional validation, then merge default arguments
825      // from the existing declarations.
826      if (!AdoptedPreviousTemplateParams &&
827          SemaRef.CheckTemplateParameterList(InstParams, PrevParams,
828                                             Sema::TPC_ClassTemplate))
829        return 0;
830    }
831  }
832
833  CXXRecordDecl *RecordInst
834    = CXXRecordDecl::Create(SemaRef.Context, Pattern->getTagKind(), DC,
835                            Pattern->getLocStart(), Pattern->getLocation(),
836                            Pattern->getIdentifier(), PrevDecl,
837                            /*DelayTypeCreation=*/true);
838
839  if (QualifierLoc)
840    RecordInst->setQualifierInfo(QualifierLoc);
841
842  ClassTemplateDecl *Inst
843    = ClassTemplateDecl::Create(SemaRef.Context, DC, D->getLocation(),
844                                D->getIdentifier(), InstParams, RecordInst,
845                                PrevClassTemplate);
846  RecordInst->setDescribedClassTemplate(Inst);
847
848  if (isFriend) {
849    if (PrevClassTemplate)
850      Inst->setAccess(PrevClassTemplate->getAccess());
851    else
852      Inst->setAccess(D->getAccess());
853
854    Inst->setObjectOfFriendDecl(PrevClassTemplate != 0);
855    // TODO: do we want to track the instantiation progeny of this
856    // friend target decl?
857  } else {
858    Inst->setAccess(D->getAccess());
859    if (!PrevClassTemplate)
860      Inst->setInstantiatedFromMemberTemplate(D);
861  }
862
863  // Trigger creation of the type for the instantiation.
864  SemaRef.Context.getInjectedClassNameType(RecordInst,
865                                    Inst->getInjectedClassNameSpecialization());
866
867  // Finish handling of friends.
868  if (isFriend) {
869    DC->makeDeclVisibleInContext(Inst, /*Recoverable*/ false);
870    return Inst;
871  }
872
873  Owner->addDecl(Inst);
874
875  if (!PrevClassTemplate) {
876    // Queue up any out-of-line partial specializations of this member
877    // class template; the client will force their instantiation once
878    // the enclosing class has been instantiated.
879    llvm::SmallVector<ClassTemplatePartialSpecializationDecl *, 4> PartialSpecs;
880    D->getPartialSpecializations(PartialSpecs);
881    for (unsigned I = 0, N = PartialSpecs.size(); I != N; ++I)
882      if (PartialSpecs[I]->isOutOfLine())
883        OutOfLinePartialSpecs.push_back(std::make_pair(Inst, PartialSpecs[I]));
884  }
885
886  return Inst;
887}
888
889Decl *
890TemplateDeclInstantiator::VisitClassTemplatePartialSpecializationDecl(
891                                   ClassTemplatePartialSpecializationDecl *D) {
892  ClassTemplateDecl *ClassTemplate = D->getSpecializedTemplate();
893
894  // Lookup the already-instantiated declaration in the instantiation
895  // of the class template and return that.
896  DeclContext::lookup_result Found
897    = Owner->lookup(ClassTemplate->getDeclName());
898  if (Found.first == Found.second)
899    return 0;
900
901  ClassTemplateDecl *InstClassTemplate
902    = dyn_cast<ClassTemplateDecl>(*Found.first);
903  if (!InstClassTemplate)
904    return 0;
905
906  if (ClassTemplatePartialSpecializationDecl *Result
907        = InstClassTemplate->findPartialSpecInstantiatedFromMember(D))
908    return Result;
909
910  return InstantiateClassTemplatePartialSpecialization(InstClassTemplate, D);
911}
912
913Decl *
914TemplateDeclInstantiator::VisitFunctionTemplateDecl(FunctionTemplateDecl *D) {
915  // Create a local instantiation scope for this function template, which
916  // will contain the instantiations of the template parameters and then get
917  // merged with the local instantiation scope for the function template
918  // itself.
919  LocalInstantiationScope Scope(SemaRef);
920
921  TemplateParameterList *TempParams = D->getTemplateParameters();
922  TemplateParameterList *InstParams = SubstTemplateParams(TempParams);
923  if (!InstParams)
924    return NULL;
925
926  FunctionDecl *Instantiated = 0;
927  if (CXXMethodDecl *DMethod = dyn_cast<CXXMethodDecl>(D->getTemplatedDecl()))
928    Instantiated = cast_or_null<FunctionDecl>(VisitCXXMethodDecl(DMethod,
929                                                                 InstParams));
930  else
931    Instantiated = cast_or_null<FunctionDecl>(VisitFunctionDecl(
932                                                          D->getTemplatedDecl(),
933                                                                InstParams));
934
935  if (!Instantiated)
936    return 0;
937
938  Instantiated->setAccess(D->getAccess());
939
940  // Link the instantiated function template declaration to the function
941  // template from which it was instantiated.
942  FunctionTemplateDecl *InstTemplate
943    = Instantiated->getDescribedFunctionTemplate();
944  InstTemplate->setAccess(D->getAccess());
945  assert(InstTemplate &&
946         "VisitFunctionDecl/CXXMethodDecl didn't create a template!");
947
948  bool isFriend = (InstTemplate->getFriendObjectKind() != Decl::FOK_None);
949
950  // Link the instantiation back to the pattern *unless* this is a
951  // non-definition friend declaration.
952  if (!InstTemplate->getInstantiatedFromMemberTemplate() &&
953      !(isFriend && !D->getTemplatedDecl()->isThisDeclarationADefinition()))
954    InstTemplate->setInstantiatedFromMemberTemplate(D);
955
956  // Make declarations visible in the appropriate context.
957  if (!isFriend)
958    Owner->addDecl(InstTemplate);
959
960  return InstTemplate;
961}
962
963Decl *TemplateDeclInstantiator::VisitCXXRecordDecl(CXXRecordDecl *D) {
964  CXXRecordDecl *PrevDecl = 0;
965  if (D->isInjectedClassName())
966    PrevDecl = cast<CXXRecordDecl>(Owner);
967  else if (D->getPreviousDeclaration()) {
968    NamedDecl *Prev = SemaRef.FindInstantiatedDecl(D->getLocation(),
969                                                   D->getPreviousDeclaration(),
970                                                   TemplateArgs);
971    if (!Prev) return 0;
972    PrevDecl = cast<CXXRecordDecl>(Prev);
973  }
974
975  CXXRecordDecl *Record
976    = CXXRecordDecl::Create(SemaRef.Context, D->getTagKind(), Owner,
977                            D->getLocStart(), D->getLocation(),
978                            D->getIdentifier(), PrevDecl);
979
980  // Substitute the nested name specifier, if any.
981  if (SubstQualifier(D, Record))
982    return 0;
983
984  Record->setImplicit(D->isImplicit());
985  // FIXME: Check against AS_none is an ugly hack to work around the issue that
986  // the tag decls introduced by friend class declarations don't have an access
987  // specifier. Remove once this area of the code gets sorted out.
988  if (D->getAccess() != AS_none)
989    Record->setAccess(D->getAccess());
990  if (!D->isInjectedClassName())
991    Record->setInstantiationOfMemberClass(D, TSK_ImplicitInstantiation);
992
993  // If the original function was part of a friend declaration,
994  // inherit its namespace state.
995  if (Decl::FriendObjectKind FOK = D->getFriendObjectKind())
996    Record->setObjectOfFriendDecl(FOK == Decl::FOK_Declared);
997
998  // Make sure that anonymous structs and unions are recorded.
999  if (D->isAnonymousStructOrUnion()) {
1000    Record->setAnonymousStructOrUnion(true);
1001    if (Record->getDeclContext()->getRedeclContext()->isFunctionOrMethod())
1002      SemaRef.CurrentInstantiationScope->InstantiatedLocal(D, Record);
1003  }
1004
1005  Owner->addDecl(Record);
1006  return Record;
1007}
1008
1009/// Normal class members are of more specific types and therefore
1010/// don't make it here.  This function serves two purposes:
1011///   1) instantiating function templates
1012///   2) substituting friend declarations
1013/// FIXME: preserve function definitions in case #2
1014Decl *TemplateDeclInstantiator::VisitFunctionDecl(FunctionDecl *D,
1015                                       TemplateParameterList *TemplateParams) {
1016  // Check whether there is already a function template specialization for
1017  // this declaration.
1018  FunctionTemplateDecl *FunctionTemplate = D->getDescribedFunctionTemplate();
1019  void *InsertPos = 0;
1020  if (FunctionTemplate && !TemplateParams) {
1021    std::pair<const TemplateArgument *, unsigned> Innermost
1022      = TemplateArgs.getInnermost();
1023
1024    FunctionDecl *SpecFunc
1025      = FunctionTemplate->findSpecialization(Innermost.first, Innermost.second,
1026                                             InsertPos);
1027
1028    // If we already have a function template specialization, return it.
1029    if (SpecFunc)
1030      return SpecFunc;
1031  }
1032
1033  bool isFriend;
1034  if (FunctionTemplate)
1035    isFriend = (FunctionTemplate->getFriendObjectKind() != Decl::FOK_None);
1036  else
1037    isFriend = (D->getFriendObjectKind() != Decl::FOK_None);
1038
1039  bool MergeWithParentScope = (TemplateParams != 0) ||
1040    Owner->isFunctionOrMethod() ||
1041    !(isa<Decl>(Owner) &&
1042      cast<Decl>(Owner)->isDefinedOutsideFunctionOrMethod());
1043  LocalInstantiationScope Scope(SemaRef, MergeWithParentScope);
1044
1045  llvm::SmallVector<ParmVarDecl *, 4> Params;
1046  TypeSourceInfo *TInfo = D->getTypeSourceInfo();
1047  TInfo = SubstFunctionType(D, Params);
1048  if (!TInfo)
1049    return 0;
1050  QualType T = TInfo->getType();
1051
1052  NestedNameSpecifierLoc QualifierLoc = D->getQualifierLoc();
1053  if (QualifierLoc) {
1054    QualifierLoc = SemaRef.SubstNestedNameSpecifierLoc(QualifierLoc,
1055                                                       TemplateArgs);
1056    if (!QualifierLoc)
1057      return 0;
1058  }
1059
1060  // If we're instantiating a local function declaration, put the result
1061  // in the owner;  otherwise we need to find the instantiated context.
1062  DeclContext *DC;
1063  if (D->getDeclContext()->isFunctionOrMethod())
1064    DC = Owner;
1065  else if (isFriend && QualifierLoc) {
1066    CXXScopeSpec SS;
1067    SS.Adopt(QualifierLoc);
1068    DC = SemaRef.computeDeclContext(SS);
1069    if (!DC) return 0;
1070  } else {
1071    DC = SemaRef.FindInstantiatedContext(D->getLocation(), D->getDeclContext(),
1072                                         TemplateArgs);
1073  }
1074
1075  FunctionDecl *Function =
1076      FunctionDecl::Create(SemaRef.Context, DC, D->getInnerLocStart(),
1077                           D->getLocation(), D->getDeclName(), T, TInfo,
1078                           D->getStorageClass(), D->getStorageClassAsWritten(),
1079                           D->isInlineSpecified(), D->hasWrittenPrototype());
1080
1081  if (QualifierLoc)
1082    Function->setQualifierInfo(QualifierLoc);
1083
1084  DeclContext *LexicalDC = Owner;
1085  if (!isFriend && D->isOutOfLine()) {
1086    assert(D->getDeclContext()->isFileContext());
1087    LexicalDC = D->getDeclContext();
1088  }
1089
1090  Function->setLexicalDeclContext(LexicalDC);
1091
1092  // Attach the parameters
1093  for (unsigned P = 0; P < Params.size(); ++P)
1094    if (Params[P])
1095      Params[P]->setOwningFunction(Function);
1096  Function->setParams(Params.data(), Params.size());
1097
1098  SourceLocation InstantiateAtPOI;
1099  if (TemplateParams) {
1100    // Our resulting instantiation is actually a function template, since we
1101    // are substituting only the outer template parameters. For example, given
1102    //
1103    //   template<typename T>
1104    //   struct X {
1105    //     template<typename U> friend void f(T, U);
1106    //   };
1107    //
1108    //   X<int> x;
1109    //
1110    // We are instantiating the friend function template "f" within X<int>,
1111    // which means substituting int for T, but leaving "f" as a friend function
1112    // template.
1113    // Build the function template itself.
1114    FunctionTemplate = FunctionTemplateDecl::Create(SemaRef.Context, DC,
1115                                                    Function->getLocation(),
1116                                                    Function->getDeclName(),
1117                                                    TemplateParams, Function);
1118    Function->setDescribedFunctionTemplate(FunctionTemplate);
1119
1120    FunctionTemplate->setLexicalDeclContext(LexicalDC);
1121
1122    if (isFriend && D->isThisDeclarationADefinition()) {
1123      // TODO: should we remember this connection regardless of whether
1124      // the friend declaration provided a body?
1125      FunctionTemplate->setInstantiatedFromMemberTemplate(
1126                                           D->getDescribedFunctionTemplate());
1127    }
1128  } else if (FunctionTemplate) {
1129    // Record this function template specialization.
1130    std::pair<const TemplateArgument *, unsigned> Innermost
1131      = TemplateArgs.getInnermost();
1132    Function->setFunctionTemplateSpecialization(FunctionTemplate,
1133                            TemplateArgumentList::CreateCopy(SemaRef.Context,
1134                                                             Innermost.first,
1135                                                             Innermost.second),
1136                                                InsertPos);
1137  } else if (isFriend && D->isThisDeclarationADefinition()) {
1138    // TODO: should we remember this connection regardless of whether
1139    // the friend declaration provided a body?
1140    Function->setInstantiationOfMemberFunction(D, TSK_ImplicitInstantiation);
1141  }
1142
1143  if (InitFunctionInstantiation(Function, D))
1144    Function->setInvalidDecl();
1145
1146  bool Redeclaration = false;
1147  bool isExplicitSpecialization = false;
1148
1149  LookupResult Previous(SemaRef, Function->getDeclName(), SourceLocation(),
1150                        Sema::LookupOrdinaryName, Sema::ForRedeclaration);
1151
1152  if (DependentFunctionTemplateSpecializationInfo *Info
1153        = D->getDependentSpecializationInfo()) {
1154    assert(isFriend && "non-friend has dependent specialization info?");
1155
1156    // This needs to be set now for future sanity.
1157    Function->setObjectOfFriendDecl(/*HasPrevious*/ true);
1158
1159    // Instantiate the explicit template arguments.
1160    TemplateArgumentListInfo ExplicitArgs(Info->getLAngleLoc(),
1161                                          Info->getRAngleLoc());
1162    if (SemaRef.Subst(Info->getTemplateArgs(), Info->getNumTemplateArgs(),
1163                      ExplicitArgs, TemplateArgs))
1164      return 0;
1165
1166    // Map the candidate templates to their instantiations.
1167    for (unsigned I = 0, E = Info->getNumTemplates(); I != E; ++I) {
1168      Decl *Temp = SemaRef.FindInstantiatedDecl(D->getLocation(),
1169                                                Info->getTemplate(I),
1170                                                TemplateArgs);
1171      if (!Temp) return 0;
1172
1173      Previous.addDecl(cast<FunctionTemplateDecl>(Temp));
1174    }
1175
1176    if (SemaRef.CheckFunctionTemplateSpecialization(Function,
1177                                                    &ExplicitArgs,
1178                                                    Previous))
1179      Function->setInvalidDecl();
1180
1181    isExplicitSpecialization = true;
1182
1183  } else if (TemplateParams || !FunctionTemplate) {
1184    // Look only into the namespace where the friend would be declared to
1185    // find a previous declaration. This is the innermost enclosing namespace,
1186    // as described in ActOnFriendFunctionDecl.
1187    SemaRef.LookupQualifiedName(Previous, DC);
1188
1189    // In C++, the previous declaration we find might be a tag type
1190    // (class or enum). In this case, the new declaration will hide the
1191    // tag type. Note that this does does not apply if we're declaring a
1192    // typedef (C++ [dcl.typedef]p4).
1193    if (Previous.isSingleTagDecl())
1194      Previous.clear();
1195  }
1196
1197  SemaRef.CheckFunctionDeclaration(/*Scope*/ 0, Function, Previous,
1198                                   isExplicitSpecialization, Redeclaration);
1199
1200  NamedDecl *PrincipalDecl = (TemplateParams
1201                              ? cast<NamedDecl>(FunctionTemplate)
1202                              : Function);
1203
1204  // If the original function was part of a friend declaration,
1205  // inherit its namespace state and add it to the owner.
1206  if (isFriend) {
1207    NamedDecl *PrevDecl;
1208    if (TemplateParams)
1209      PrevDecl = FunctionTemplate->getPreviousDeclaration();
1210    else
1211      PrevDecl = Function->getPreviousDeclaration();
1212
1213    PrincipalDecl->setObjectOfFriendDecl(PrevDecl != 0);
1214    DC->makeDeclVisibleInContext(PrincipalDecl, /*Recoverable=*/ false);
1215
1216    bool queuedInstantiation = false;
1217
1218    if (!SemaRef.getLangOptions().CPlusPlus0x &&
1219        D->isThisDeclarationADefinition()) {
1220      // Check for a function body.
1221      const FunctionDecl *Definition = 0;
1222      if (Function->isDefined(Definition) &&
1223          Definition->getTemplateSpecializationKind() == TSK_Undeclared) {
1224        SemaRef.Diag(Function->getLocation(), diag::err_redefinition)
1225          << Function->getDeclName();
1226        SemaRef.Diag(Definition->getLocation(), diag::note_previous_definition);
1227        Function->setInvalidDecl();
1228      }
1229      // Check for redefinitions due to other instantiations of this or
1230      // a similar friend function.
1231      else for (FunctionDecl::redecl_iterator R = Function->redecls_begin(),
1232                                           REnd = Function->redecls_end();
1233                R != REnd; ++R) {
1234        if (*R == Function)
1235          continue;
1236        switch (R->getFriendObjectKind()) {
1237        case Decl::FOK_None:
1238          if (!queuedInstantiation && R->isUsed(false)) {
1239            if (MemberSpecializationInfo *MSInfo
1240                = Function->getMemberSpecializationInfo()) {
1241              if (MSInfo->getPointOfInstantiation().isInvalid()) {
1242                SourceLocation Loc = R->getLocation(); // FIXME
1243                MSInfo->setPointOfInstantiation(Loc);
1244                SemaRef.PendingLocalImplicitInstantiations.push_back(
1245                                                 std::make_pair(Function, Loc));
1246                queuedInstantiation = true;
1247              }
1248            }
1249          }
1250          break;
1251        default:
1252          if (const FunctionDecl *RPattern
1253              = R->getTemplateInstantiationPattern())
1254            if (RPattern->isDefined(RPattern)) {
1255              SemaRef.Diag(Function->getLocation(), diag::err_redefinition)
1256                << Function->getDeclName();
1257              SemaRef.Diag(R->getLocation(), diag::note_previous_definition);
1258              Function->setInvalidDecl();
1259              break;
1260            }
1261        }
1262      }
1263    }
1264  }
1265
1266  if (Function->isOverloadedOperator() && !DC->isRecord() &&
1267      PrincipalDecl->isInIdentifierNamespace(Decl::IDNS_Ordinary))
1268    PrincipalDecl->setNonMemberOperator();
1269
1270  assert(!D->isDefaulted() && "only methods should be defaulted");
1271  return Function;
1272}
1273
1274Decl *
1275TemplateDeclInstantiator::VisitCXXMethodDecl(CXXMethodDecl *D,
1276                                      TemplateParameterList *TemplateParams) {
1277  FunctionTemplateDecl *FunctionTemplate = D->getDescribedFunctionTemplate();
1278  void *InsertPos = 0;
1279  if (FunctionTemplate && !TemplateParams) {
1280    // We are creating a function template specialization from a function
1281    // template. Check whether there is already a function template
1282    // specialization for this particular set of template arguments.
1283    std::pair<const TemplateArgument *, unsigned> Innermost
1284      = TemplateArgs.getInnermost();
1285
1286    FunctionDecl *SpecFunc
1287      = FunctionTemplate->findSpecialization(Innermost.first, Innermost.second,
1288                                             InsertPos);
1289
1290    // If we already have a function template specialization, return it.
1291    if (SpecFunc)
1292      return SpecFunc;
1293  }
1294
1295  bool isFriend;
1296  if (FunctionTemplate)
1297    isFriend = (FunctionTemplate->getFriendObjectKind() != Decl::FOK_None);
1298  else
1299    isFriend = (D->getFriendObjectKind() != Decl::FOK_None);
1300
1301  bool MergeWithParentScope = (TemplateParams != 0) ||
1302    !(isa<Decl>(Owner) &&
1303      cast<Decl>(Owner)->isDefinedOutsideFunctionOrMethod());
1304  LocalInstantiationScope Scope(SemaRef, MergeWithParentScope);
1305
1306  // Instantiate enclosing template arguments for friends.
1307  llvm::SmallVector<TemplateParameterList *, 4> TempParamLists;
1308  unsigned NumTempParamLists = 0;
1309  if (isFriend && (NumTempParamLists = D->getNumTemplateParameterLists())) {
1310    TempParamLists.set_size(NumTempParamLists);
1311    for (unsigned I = 0; I != NumTempParamLists; ++I) {
1312      TemplateParameterList *TempParams = D->getTemplateParameterList(I);
1313      TemplateParameterList *InstParams = SubstTemplateParams(TempParams);
1314      if (!InstParams)
1315        return NULL;
1316      TempParamLists[I] = InstParams;
1317    }
1318  }
1319
1320  llvm::SmallVector<ParmVarDecl *, 4> Params;
1321  TypeSourceInfo *TInfo = D->getTypeSourceInfo();
1322  TInfo = SubstFunctionType(D, Params);
1323  if (!TInfo)
1324    return 0;
1325  QualType T = TInfo->getType();
1326
1327  // \brief If the type of this function, after ignoring parentheses,
1328  // is not *directly* a function type, then we're instantiating a function
1329  // that was declared via a typedef, e.g.,
1330  //
1331  //   typedef int functype(int, int);
1332  //   functype func;
1333  //
1334  // In this case, we'll just go instantiate the ParmVarDecls that we
1335  // synthesized in the method declaration.
1336  if (!isa<FunctionProtoType>(T.IgnoreParens())) {
1337    assert(!Params.size() && "Instantiating type could not yield parameters");
1338    llvm::SmallVector<QualType, 4> ParamTypes;
1339    if (SemaRef.SubstParmTypes(D->getLocation(), D->param_begin(),
1340                               D->getNumParams(), TemplateArgs, ParamTypes,
1341                               &Params))
1342      return 0;
1343  }
1344
1345  NestedNameSpecifierLoc QualifierLoc = D->getQualifierLoc();
1346  if (QualifierLoc) {
1347    QualifierLoc = SemaRef.SubstNestedNameSpecifierLoc(QualifierLoc,
1348                                                 TemplateArgs);
1349    if (!QualifierLoc)
1350      return 0;
1351  }
1352
1353  DeclContext *DC = Owner;
1354  if (isFriend) {
1355    if (QualifierLoc) {
1356      CXXScopeSpec SS;
1357      SS.Adopt(QualifierLoc);
1358      DC = SemaRef.computeDeclContext(SS);
1359
1360      if (DC && SemaRef.RequireCompleteDeclContext(SS, DC))
1361        return 0;
1362    } else {
1363      DC = SemaRef.FindInstantiatedContext(D->getLocation(),
1364                                           D->getDeclContext(),
1365                                           TemplateArgs);
1366    }
1367    if (!DC) return 0;
1368  }
1369
1370  // Build the instantiated method declaration.
1371  CXXRecordDecl *Record = cast<CXXRecordDecl>(DC);
1372  CXXMethodDecl *Method = 0;
1373
1374  SourceLocation StartLoc = D->getInnerLocStart();
1375  DeclarationNameInfo NameInfo
1376    = SemaRef.SubstDeclarationNameInfo(D->getNameInfo(), TemplateArgs);
1377  if (CXXConstructorDecl *Constructor = dyn_cast<CXXConstructorDecl>(D)) {
1378    Method = CXXConstructorDecl::Create(SemaRef.Context, Record,
1379                                        StartLoc, NameInfo, T, TInfo,
1380                                        Constructor->isExplicit(),
1381                                        Constructor->isInlineSpecified(),
1382                                        false);
1383  } else if (CXXDestructorDecl *Destructor = dyn_cast<CXXDestructorDecl>(D)) {
1384    Method = CXXDestructorDecl::Create(SemaRef.Context, Record,
1385                                       StartLoc, NameInfo, T, TInfo,
1386                                       Destructor->isInlineSpecified(),
1387                                       false);
1388  } else if (CXXConversionDecl *Conversion = dyn_cast<CXXConversionDecl>(D)) {
1389    Method = CXXConversionDecl::Create(SemaRef.Context, Record,
1390                                       StartLoc, NameInfo, T, TInfo,
1391                                       Conversion->isInlineSpecified(),
1392                                       Conversion->isExplicit(),
1393                                       Conversion->getLocEnd());
1394  } else {
1395    Method = CXXMethodDecl::Create(SemaRef.Context, Record,
1396                                   StartLoc, NameInfo, T, TInfo,
1397                                   D->isStatic(),
1398                                   D->getStorageClassAsWritten(),
1399                                   D->isInlineSpecified(),
1400                                   D->getLocEnd());
1401  }
1402
1403  if (QualifierLoc)
1404    Method->setQualifierInfo(QualifierLoc);
1405
1406  if (TemplateParams) {
1407    // Our resulting instantiation is actually a function template, since we
1408    // are substituting only the outer template parameters. For example, given
1409    //
1410    //   template<typename T>
1411    //   struct X {
1412    //     template<typename U> void f(T, U);
1413    //   };
1414    //
1415    //   X<int> x;
1416    //
1417    // We are instantiating the member template "f" within X<int>, which means
1418    // substituting int for T, but leaving "f" as a member function template.
1419    // Build the function template itself.
1420    FunctionTemplate = FunctionTemplateDecl::Create(SemaRef.Context, Record,
1421                                                    Method->getLocation(),
1422                                                    Method->getDeclName(),
1423                                                    TemplateParams, Method);
1424    if (isFriend) {
1425      FunctionTemplate->setLexicalDeclContext(Owner);
1426      FunctionTemplate->setObjectOfFriendDecl(true);
1427    } else if (D->isOutOfLine())
1428      FunctionTemplate->setLexicalDeclContext(D->getLexicalDeclContext());
1429    Method->setDescribedFunctionTemplate(FunctionTemplate);
1430  } else if (FunctionTemplate) {
1431    // Record this function template specialization.
1432    std::pair<const TemplateArgument *, unsigned> Innermost
1433      = TemplateArgs.getInnermost();
1434    Method->setFunctionTemplateSpecialization(FunctionTemplate,
1435                         TemplateArgumentList::CreateCopy(SemaRef.Context,
1436                                                          Innermost.first,
1437                                                          Innermost.second),
1438                                              InsertPos);
1439  } else if (!isFriend) {
1440    // Record that this is an instantiation of a member function.
1441    Method->setInstantiationOfMemberFunction(D, TSK_ImplicitInstantiation);
1442  }
1443
1444  // If we are instantiating a member function defined
1445  // out-of-line, the instantiation will have the same lexical
1446  // context (which will be a namespace scope) as the template.
1447  if (isFriend) {
1448    if (NumTempParamLists)
1449      Method->setTemplateParameterListsInfo(SemaRef.Context,
1450                                            NumTempParamLists,
1451                                            TempParamLists.data());
1452
1453    Method->setLexicalDeclContext(Owner);
1454    Method->setObjectOfFriendDecl(true);
1455  } else if (D->isOutOfLine())
1456    Method->setLexicalDeclContext(D->getLexicalDeclContext());
1457
1458  // Attach the parameters
1459  for (unsigned P = 0; P < Params.size(); ++P)
1460    Params[P]->setOwningFunction(Method);
1461  Method->setParams(Params.data(), Params.size());
1462
1463  if (InitMethodInstantiation(Method, D))
1464    Method->setInvalidDecl();
1465
1466  LookupResult Previous(SemaRef, NameInfo, Sema::LookupOrdinaryName,
1467                        Sema::ForRedeclaration);
1468
1469  if (!FunctionTemplate || TemplateParams || isFriend) {
1470    SemaRef.LookupQualifiedName(Previous, Record);
1471
1472    // In C++, the previous declaration we find might be a tag type
1473    // (class or enum). In this case, the new declaration will hide the
1474    // tag type. Note that this does does not apply if we're declaring a
1475    // typedef (C++ [dcl.typedef]p4).
1476    if (Previous.isSingleTagDecl())
1477      Previous.clear();
1478  }
1479
1480  bool Redeclaration = false;
1481  SemaRef.CheckFunctionDeclaration(0, Method, Previous, false, Redeclaration);
1482
1483  if (D->isPure())
1484    SemaRef.CheckPureMethod(Method, SourceRange());
1485
1486  Method->setAccess(D->getAccess());
1487
1488  SemaRef.CheckOverrideControl(Method);
1489
1490  if (FunctionTemplate) {
1491    // If there's a function template, let our caller handle it.
1492  } else if (Method->isInvalidDecl() && !Previous.empty()) {
1493    // Don't hide a (potentially) valid declaration with an invalid one.
1494  } else {
1495    NamedDecl *DeclToAdd = (TemplateParams
1496                            ? cast<NamedDecl>(FunctionTemplate)
1497                            : Method);
1498    if (isFriend)
1499      Record->makeDeclVisibleInContext(DeclToAdd);
1500    else
1501      Owner->addDecl(DeclToAdd);
1502  }
1503
1504  if (D->isExplicitlyDefaulted()) {
1505    SemaRef.SetDeclDefaulted(Method, Method->getLocation());
1506  } else {
1507    assert(!D->isDefaulted() &&
1508           "should not implicitly default uninstantiated function");
1509  }
1510
1511  return Method;
1512}
1513
1514Decl *TemplateDeclInstantiator::VisitCXXConstructorDecl(CXXConstructorDecl *D) {
1515  return VisitCXXMethodDecl(D);
1516}
1517
1518Decl *TemplateDeclInstantiator::VisitCXXDestructorDecl(CXXDestructorDecl *D) {
1519  return VisitCXXMethodDecl(D);
1520}
1521
1522Decl *TemplateDeclInstantiator::VisitCXXConversionDecl(CXXConversionDecl *D) {
1523  return VisitCXXMethodDecl(D);
1524}
1525
1526ParmVarDecl *TemplateDeclInstantiator::VisitParmVarDecl(ParmVarDecl *D) {
1527  return SemaRef.SubstParmVarDecl(D, TemplateArgs, /*indexAdjustment*/ 0,
1528                                  llvm::Optional<unsigned>());
1529}
1530
1531Decl *TemplateDeclInstantiator::VisitTemplateTypeParmDecl(
1532                                                    TemplateTypeParmDecl *D) {
1533  // TODO: don't always clone when decls are refcounted.
1534  assert(D->getTypeForDecl()->isTemplateTypeParmType());
1535
1536  TemplateTypeParmDecl *Inst =
1537    TemplateTypeParmDecl::Create(SemaRef.Context, Owner,
1538                                 D->getLocStart(), D->getLocation(),
1539                                 D->getDepth() - TemplateArgs.getNumLevels(),
1540                                 D->getIndex(), D->getIdentifier(),
1541                                 D->wasDeclaredWithTypename(),
1542                                 D->isParameterPack());
1543  Inst->setAccess(AS_public);
1544
1545  if (D->hasDefaultArgument())
1546    Inst->setDefaultArgument(D->getDefaultArgumentInfo(), false);
1547
1548  // Introduce this template parameter's instantiation into the instantiation
1549  // scope.
1550  SemaRef.CurrentInstantiationScope->InstantiatedLocal(D, Inst);
1551
1552  return Inst;
1553}
1554
1555Decl *TemplateDeclInstantiator::VisitNonTypeTemplateParmDecl(
1556                                                 NonTypeTemplateParmDecl *D) {
1557  // Substitute into the type of the non-type template parameter.
1558  TypeLoc TL = D->getTypeSourceInfo()->getTypeLoc();
1559  llvm::SmallVector<TypeSourceInfo *, 4> ExpandedParameterPackTypesAsWritten;
1560  llvm::SmallVector<QualType, 4> ExpandedParameterPackTypes;
1561  bool IsExpandedParameterPack = false;
1562  TypeSourceInfo *DI;
1563  QualType T;
1564  bool Invalid = false;
1565
1566  if (D->isExpandedParameterPack()) {
1567    // The non-type template parameter pack is an already-expanded pack
1568    // expansion of types. Substitute into each of the expanded types.
1569    ExpandedParameterPackTypes.reserve(D->getNumExpansionTypes());
1570    ExpandedParameterPackTypesAsWritten.reserve(D->getNumExpansionTypes());
1571    for (unsigned I = 0, N = D->getNumExpansionTypes(); I != N; ++I) {
1572      TypeSourceInfo *NewDI =SemaRef.SubstType(D->getExpansionTypeSourceInfo(I),
1573                                               TemplateArgs,
1574                                               D->getLocation(),
1575                                               D->getDeclName());
1576      if (!NewDI)
1577        return 0;
1578
1579      ExpandedParameterPackTypesAsWritten.push_back(NewDI);
1580      QualType NewT =SemaRef.CheckNonTypeTemplateParameterType(NewDI->getType(),
1581                                                              D->getLocation());
1582      if (NewT.isNull())
1583        return 0;
1584      ExpandedParameterPackTypes.push_back(NewT);
1585    }
1586
1587    IsExpandedParameterPack = true;
1588    DI = D->getTypeSourceInfo();
1589    T = DI->getType();
1590  } else if (isa<PackExpansionTypeLoc>(TL)) {
1591    // The non-type template parameter pack's type is a pack expansion of types.
1592    // Determine whether we need to expand this parameter pack into separate
1593    // types.
1594    PackExpansionTypeLoc Expansion = cast<PackExpansionTypeLoc>(TL);
1595    TypeLoc Pattern = Expansion.getPatternLoc();
1596    llvm::SmallVector<UnexpandedParameterPack, 2> Unexpanded;
1597    SemaRef.collectUnexpandedParameterPacks(Pattern, Unexpanded);
1598
1599    // Determine whether the set of unexpanded parameter packs can and should
1600    // be expanded.
1601    bool Expand = true;
1602    bool RetainExpansion = false;
1603    llvm::Optional<unsigned> OrigNumExpansions
1604      = Expansion.getTypePtr()->getNumExpansions();
1605    llvm::Optional<unsigned> NumExpansions = OrigNumExpansions;
1606    if (SemaRef.CheckParameterPacksForExpansion(Expansion.getEllipsisLoc(),
1607                                                Pattern.getSourceRange(),
1608                                                Unexpanded.data(),
1609                                                Unexpanded.size(),
1610                                                TemplateArgs,
1611                                                Expand, RetainExpansion,
1612                                                NumExpansions))
1613      return 0;
1614
1615    if (Expand) {
1616      for (unsigned I = 0; I != *NumExpansions; ++I) {
1617        Sema::ArgumentPackSubstitutionIndexRAII SubstIndex(SemaRef, I);
1618        TypeSourceInfo *NewDI = SemaRef.SubstType(Pattern, TemplateArgs,
1619                                                  D->getLocation(),
1620                                                  D->getDeclName());
1621        if (!NewDI)
1622          return 0;
1623
1624        ExpandedParameterPackTypesAsWritten.push_back(NewDI);
1625        QualType NewT = SemaRef.CheckNonTypeTemplateParameterType(
1626                                                              NewDI->getType(),
1627                                                              D->getLocation());
1628        if (NewT.isNull())
1629          return 0;
1630        ExpandedParameterPackTypes.push_back(NewT);
1631      }
1632
1633      // Note that we have an expanded parameter pack. The "type" of this
1634      // expanded parameter pack is the original expansion type, but callers
1635      // will end up using the expanded parameter pack types for type-checking.
1636      IsExpandedParameterPack = true;
1637      DI = D->getTypeSourceInfo();
1638      T = DI->getType();
1639    } else {
1640      // We cannot fully expand the pack expansion now, so substitute into the
1641      // pattern and create a new pack expansion type.
1642      Sema::ArgumentPackSubstitutionIndexRAII SubstIndex(SemaRef, -1);
1643      TypeSourceInfo *NewPattern = SemaRef.SubstType(Pattern, TemplateArgs,
1644                                                     D->getLocation(),
1645                                                     D->getDeclName());
1646      if (!NewPattern)
1647        return 0;
1648
1649      DI = SemaRef.CheckPackExpansion(NewPattern, Expansion.getEllipsisLoc(),
1650                                      NumExpansions);
1651      if (!DI)
1652        return 0;
1653
1654      T = DI->getType();
1655    }
1656  } else {
1657    // Simple case: substitution into a parameter that is not a parameter pack.
1658    DI = SemaRef.SubstType(D->getTypeSourceInfo(), TemplateArgs,
1659                           D->getLocation(), D->getDeclName());
1660    if (!DI)
1661      return 0;
1662
1663    // Check that this type is acceptable for a non-type template parameter.
1664    T = SemaRef.CheckNonTypeTemplateParameterType(DI->getType(),
1665                                                  D->getLocation());
1666    if (T.isNull()) {
1667      T = SemaRef.Context.IntTy;
1668      Invalid = true;
1669    }
1670  }
1671
1672  NonTypeTemplateParmDecl *Param;
1673  if (IsExpandedParameterPack)
1674    Param = NonTypeTemplateParmDecl::Create(SemaRef.Context, Owner,
1675                                            D->getInnerLocStart(),
1676                                            D->getLocation(),
1677                                    D->getDepth() - TemplateArgs.getNumLevels(),
1678                                            D->getPosition(),
1679                                            D->getIdentifier(), T,
1680                                            DI,
1681                                            ExpandedParameterPackTypes.data(),
1682                                            ExpandedParameterPackTypes.size(),
1683                                    ExpandedParameterPackTypesAsWritten.data());
1684  else
1685    Param = NonTypeTemplateParmDecl::Create(SemaRef.Context, Owner,
1686                                            D->getInnerLocStart(),
1687                                            D->getLocation(),
1688                                    D->getDepth() - TemplateArgs.getNumLevels(),
1689                                            D->getPosition(),
1690                                            D->getIdentifier(), T,
1691                                            D->isParameterPack(), DI);
1692
1693  Param->setAccess(AS_public);
1694  if (Invalid)
1695    Param->setInvalidDecl();
1696
1697  Param->setDefaultArgument(D->getDefaultArgument(), false);
1698
1699  // Introduce this template parameter's instantiation into the instantiation
1700  // scope.
1701  SemaRef.CurrentInstantiationScope->InstantiatedLocal(D, Param);
1702  return Param;
1703}
1704
1705Decl *
1706TemplateDeclInstantiator::VisitTemplateTemplateParmDecl(
1707                                                  TemplateTemplateParmDecl *D) {
1708  // Instantiate the template parameter list of the template template parameter.
1709  TemplateParameterList *TempParams = D->getTemplateParameters();
1710  TemplateParameterList *InstParams;
1711  {
1712    // Perform the actual substitution of template parameters within a new,
1713    // local instantiation scope.
1714    LocalInstantiationScope Scope(SemaRef);
1715    InstParams = SubstTemplateParams(TempParams);
1716    if (!InstParams)
1717      return NULL;
1718  }
1719
1720  // Build the template template parameter.
1721  TemplateTemplateParmDecl *Param
1722    = TemplateTemplateParmDecl::Create(SemaRef.Context, Owner, D->getLocation(),
1723                                   D->getDepth() - TemplateArgs.getNumLevels(),
1724                                       D->getPosition(), D->isParameterPack(),
1725                                       D->getIdentifier(), InstParams);
1726  Param->setDefaultArgument(D->getDefaultArgument(), false);
1727  Param->setAccess(AS_public);
1728
1729  // Introduce this template parameter's instantiation into the instantiation
1730  // scope.
1731  SemaRef.CurrentInstantiationScope->InstantiatedLocal(D, Param);
1732
1733  return Param;
1734}
1735
1736Decl *TemplateDeclInstantiator::VisitUsingDirectiveDecl(UsingDirectiveDecl *D) {
1737  // Using directives are never dependent (and never contain any types or
1738  // expressions), so they require no explicit instantiation work.
1739
1740  UsingDirectiveDecl *Inst
1741    = UsingDirectiveDecl::Create(SemaRef.Context, Owner, D->getLocation(),
1742                                 D->getNamespaceKeyLocation(),
1743                                 D->getQualifierLoc(),
1744                                 D->getIdentLocation(),
1745                                 D->getNominatedNamespace(),
1746                                 D->getCommonAncestor());
1747  Owner->addDecl(Inst);
1748  return Inst;
1749}
1750
1751Decl *TemplateDeclInstantiator::VisitUsingDecl(UsingDecl *D) {
1752
1753  // The nested name specifier may be dependent, for example
1754  //     template <typename T> struct t {
1755  //       struct s1 { T f1(); };
1756  //       struct s2 : s1 { using s1::f1; };
1757  //     };
1758  //     template struct t<int>;
1759  // Here, in using s1::f1, s1 refers to t<T>::s1;
1760  // we need to substitute for t<int>::s1.
1761  NestedNameSpecifierLoc QualifierLoc
1762    = SemaRef.SubstNestedNameSpecifierLoc(D->getQualifierLoc(),
1763                                          TemplateArgs);
1764  if (!QualifierLoc)
1765    return 0;
1766
1767  // The name info is non-dependent, so no transformation
1768  // is required.
1769  DeclarationNameInfo NameInfo = D->getNameInfo();
1770
1771  // We only need to do redeclaration lookups if we're in a class
1772  // scope (in fact, it's not really even possible in non-class
1773  // scopes).
1774  bool CheckRedeclaration = Owner->isRecord();
1775
1776  LookupResult Prev(SemaRef, NameInfo, Sema::LookupUsingDeclName,
1777                    Sema::ForRedeclaration);
1778
1779  UsingDecl *NewUD = UsingDecl::Create(SemaRef.Context, Owner,
1780                                       D->getUsingLocation(),
1781                                       QualifierLoc,
1782                                       NameInfo,
1783                                       D->isTypeName());
1784
1785  CXXScopeSpec SS;
1786  SS.Adopt(QualifierLoc);
1787  if (CheckRedeclaration) {
1788    Prev.setHideTags(false);
1789    SemaRef.LookupQualifiedName(Prev, Owner);
1790
1791    // Check for invalid redeclarations.
1792    if (SemaRef.CheckUsingDeclRedeclaration(D->getUsingLocation(),
1793                                            D->isTypeName(), SS,
1794                                            D->getLocation(), Prev))
1795      NewUD->setInvalidDecl();
1796
1797  }
1798
1799  if (!NewUD->isInvalidDecl() &&
1800      SemaRef.CheckUsingDeclQualifier(D->getUsingLocation(), SS,
1801                                      D->getLocation()))
1802    NewUD->setInvalidDecl();
1803
1804  SemaRef.Context.setInstantiatedFromUsingDecl(NewUD, D);
1805  NewUD->setAccess(D->getAccess());
1806  Owner->addDecl(NewUD);
1807
1808  // Don't process the shadow decls for an invalid decl.
1809  if (NewUD->isInvalidDecl())
1810    return NewUD;
1811
1812  bool isFunctionScope = Owner->isFunctionOrMethod();
1813
1814  // Process the shadow decls.
1815  for (UsingDecl::shadow_iterator I = D->shadow_begin(), E = D->shadow_end();
1816         I != E; ++I) {
1817    UsingShadowDecl *Shadow = *I;
1818    NamedDecl *InstTarget =
1819      cast_or_null<NamedDecl>(SemaRef.FindInstantiatedDecl(
1820                                                          Shadow->getLocation(),
1821                                                        Shadow->getTargetDecl(),
1822                                                           TemplateArgs));
1823    if (!InstTarget)
1824      return 0;
1825
1826    if (CheckRedeclaration &&
1827        SemaRef.CheckUsingShadowDecl(NewUD, InstTarget, Prev))
1828      continue;
1829
1830    UsingShadowDecl *InstShadow
1831      = SemaRef.BuildUsingShadowDecl(/*Scope*/ 0, NewUD, InstTarget);
1832    SemaRef.Context.setInstantiatedFromUsingShadowDecl(InstShadow, Shadow);
1833
1834    if (isFunctionScope)
1835      SemaRef.CurrentInstantiationScope->InstantiatedLocal(Shadow, InstShadow);
1836  }
1837
1838  return NewUD;
1839}
1840
1841Decl *TemplateDeclInstantiator::VisitUsingShadowDecl(UsingShadowDecl *D) {
1842  // Ignore these;  we handle them in bulk when processing the UsingDecl.
1843  return 0;
1844}
1845
1846Decl * TemplateDeclInstantiator
1847    ::VisitUnresolvedUsingTypenameDecl(UnresolvedUsingTypenameDecl *D) {
1848  NestedNameSpecifierLoc QualifierLoc
1849    = SemaRef.SubstNestedNameSpecifierLoc(D->getQualifierLoc(),
1850                                          TemplateArgs);
1851  if (!QualifierLoc)
1852    return 0;
1853
1854  CXXScopeSpec SS;
1855  SS.Adopt(QualifierLoc);
1856
1857  // Since NameInfo refers to a typename, it cannot be a C++ special name.
1858  // Hence, no tranformation is required for it.
1859  DeclarationNameInfo NameInfo(D->getDeclName(), D->getLocation());
1860  NamedDecl *UD =
1861    SemaRef.BuildUsingDeclaration(/*Scope*/ 0, D->getAccess(),
1862                                  D->getUsingLoc(), SS, NameInfo, 0,
1863                                  /*instantiation*/ true,
1864                                  /*typename*/ true, D->getTypenameLoc());
1865  if (UD)
1866    SemaRef.Context.setInstantiatedFromUsingDecl(cast<UsingDecl>(UD), D);
1867
1868  return UD;
1869}
1870
1871Decl * TemplateDeclInstantiator
1872    ::VisitUnresolvedUsingValueDecl(UnresolvedUsingValueDecl *D) {
1873  NestedNameSpecifierLoc QualifierLoc
1874      = SemaRef.SubstNestedNameSpecifierLoc(D->getQualifierLoc(), TemplateArgs);
1875  if (!QualifierLoc)
1876    return 0;
1877
1878  CXXScopeSpec SS;
1879  SS.Adopt(QualifierLoc);
1880
1881  DeclarationNameInfo NameInfo
1882    = SemaRef.SubstDeclarationNameInfo(D->getNameInfo(), TemplateArgs);
1883
1884  NamedDecl *UD =
1885    SemaRef.BuildUsingDeclaration(/*Scope*/ 0, D->getAccess(),
1886                                  D->getUsingLoc(), SS, NameInfo, 0,
1887                                  /*instantiation*/ true,
1888                                  /*typename*/ false, SourceLocation());
1889  if (UD)
1890    SemaRef.Context.setInstantiatedFromUsingDecl(cast<UsingDecl>(UD), D);
1891
1892  return UD;
1893}
1894
1895Decl *Sema::SubstDecl(Decl *D, DeclContext *Owner,
1896                      const MultiLevelTemplateArgumentList &TemplateArgs) {
1897  TemplateDeclInstantiator Instantiator(*this, Owner, TemplateArgs);
1898  if (D->isInvalidDecl())
1899    return 0;
1900
1901  return Instantiator.Visit(D);
1902}
1903
1904/// \brief Instantiates a nested template parameter list in the current
1905/// instantiation context.
1906///
1907/// \param L The parameter list to instantiate
1908///
1909/// \returns NULL if there was an error
1910TemplateParameterList *
1911TemplateDeclInstantiator::SubstTemplateParams(TemplateParameterList *L) {
1912  // Get errors for all the parameters before bailing out.
1913  bool Invalid = false;
1914
1915  unsigned N = L->size();
1916  typedef llvm::SmallVector<NamedDecl *, 8> ParamVector;
1917  ParamVector Params;
1918  Params.reserve(N);
1919  for (TemplateParameterList::iterator PI = L->begin(), PE = L->end();
1920       PI != PE; ++PI) {
1921    NamedDecl *D = cast_or_null<NamedDecl>(Visit(*PI));
1922    Params.push_back(D);
1923    Invalid = Invalid || !D || D->isInvalidDecl();
1924  }
1925
1926  // Clean up if we had an error.
1927  if (Invalid)
1928    return NULL;
1929
1930  TemplateParameterList *InstL
1931    = TemplateParameterList::Create(SemaRef.Context, L->getTemplateLoc(),
1932                                    L->getLAngleLoc(), &Params.front(), N,
1933                                    L->getRAngleLoc());
1934  return InstL;
1935}
1936
1937/// \brief Instantiate the declaration of a class template partial
1938/// specialization.
1939///
1940/// \param ClassTemplate the (instantiated) class template that is partially
1941// specialized by the instantiation of \p PartialSpec.
1942///
1943/// \param PartialSpec the (uninstantiated) class template partial
1944/// specialization that we are instantiating.
1945///
1946/// \returns The instantiated partial specialization, if successful; otherwise,
1947/// NULL to indicate an error.
1948ClassTemplatePartialSpecializationDecl *
1949TemplateDeclInstantiator::InstantiateClassTemplatePartialSpecialization(
1950                                            ClassTemplateDecl *ClassTemplate,
1951                          ClassTemplatePartialSpecializationDecl *PartialSpec) {
1952  // Create a local instantiation scope for this class template partial
1953  // specialization, which will contain the instantiations of the template
1954  // parameters.
1955  LocalInstantiationScope Scope(SemaRef);
1956
1957  // Substitute into the template parameters of the class template partial
1958  // specialization.
1959  TemplateParameterList *TempParams = PartialSpec->getTemplateParameters();
1960  TemplateParameterList *InstParams = SubstTemplateParams(TempParams);
1961  if (!InstParams)
1962    return 0;
1963
1964  // Substitute into the template arguments of the class template partial
1965  // specialization.
1966  TemplateArgumentListInfo InstTemplateArgs; // no angle locations
1967  if (SemaRef.Subst(PartialSpec->getTemplateArgsAsWritten(),
1968                    PartialSpec->getNumTemplateArgsAsWritten(),
1969                    InstTemplateArgs, TemplateArgs))
1970    return 0;
1971
1972  // Check that the template argument list is well-formed for this
1973  // class template.
1974  llvm::SmallVector<TemplateArgument, 4> Converted;
1975  if (SemaRef.CheckTemplateArgumentList(ClassTemplate,
1976                                        PartialSpec->getLocation(),
1977                                        InstTemplateArgs,
1978                                        false,
1979                                        Converted))
1980    return 0;
1981
1982  // Figure out where to insert this class template partial specialization
1983  // in the member template's set of class template partial specializations.
1984  void *InsertPos = 0;
1985  ClassTemplateSpecializationDecl *PrevDecl
1986    = ClassTemplate->findPartialSpecialization(Converted.data(),
1987                                               Converted.size(), InsertPos);
1988
1989  // Build the canonical type that describes the converted template
1990  // arguments of the class template partial specialization.
1991  QualType CanonType
1992    = SemaRef.Context.getTemplateSpecializationType(TemplateName(ClassTemplate),
1993                                                    Converted.data(),
1994                                                    Converted.size());
1995
1996  // Build the fully-sugared type for this class template
1997  // specialization as the user wrote in the specialization
1998  // itself. This means that we'll pretty-print the type retrieved
1999  // from the specialization's declaration the way that the user
2000  // actually wrote the specialization, rather than formatting the
2001  // name based on the "canonical" representation used to store the
2002  // template arguments in the specialization.
2003  TypeSourceInfo *WrittenTy
2004    = SemaRef.Context.getTemplateSpecializationTypeInfo(
2005                                                    TemplateName(ClassTemplate),
2006                                                    PartialSpec->getLocation(),
2007                                                    InstTemplateArgs,
2008                                                    CanonType);
2009
2010  if (PrevDecl) {
2011    // We've already seen a partial specialization with the same template
2012    // parameters and template arguments. This can happen, for example, when
2013    // substituting the outer template arguments ends up causing two
2014    // class template partial specializations of a member class template
2015    // to have identical forms, e.g.,
2016    //
2017    //   template<typename T, typename U>
2018    //   struct Outer {
2019    //     template<typename X, typename Y> struct Inner;
2020    //     template<typename Y> struct Inner<T, Y>;
2021    //     template<typename Y> struct Inner<U, Y>;
2022    //   };
2023    //
2024    //   Outer<int, int> outer; // error: the partial specializations of Inner
2025    //                          // have the same signature.
2026    SemaRef.Diag(PartialSpec->getLocation(), diag::err_partial_spec_redeclared)
2027      << WrittenTy->getType();
2028    SemaRef.Diag(PrevDecl->getLocation(), diag::note_prev_partial_spec_here)
2029      << SemaRef.Context.getTypeDeclType(PrevDecl);
2030    return 0;
2031  }
2032
2033
2034  // Create the class template partial specialization declaration.
2035  ClassTemplatePartialSpecializationDecl *InstPartialSpec
2036    = ClassTemplatePartialSpecializationDecl::Create(SemaRef.Context,
2037                                                     PartialSpec->getTagKind(),
2038                                                     Owner,
2039                                                     PartialSpec->getLocStart(),
2040                                                     PartialSpec->getLocation(),
2041                                                     InstParams,
2042                                                     ClassTemplate,
2043                                                     Converted.data(),
2044                                                     Converted.size(),
2045                                                     InstTemplateArgs,
2046                                                     CanonType,
2047                                                     0,
2048                             ClassTemplate->getNextPartialSpecSequenceNumber());
2049  // Substitute the nested name specifier, if any.
2050  if (SubstQualifier(PartialSpec, InstPartialSpec))
2051    return 0;
2052
2053  InstPartialSpec->setInstantiatedFromMember(PartialSpec);
2054  InstPartialSpec->setTypeAsWritten(WrittenTy);
2055
2056  // Add this partial specialization to the set of class template partial
2057  // specializations.
2058  ClassTemplate->AddPartialSpecialization(InstPartialSpec, InsertPos);
2059  return InstPartialSpec;
2060}
2061
2062TypeSourceInfo*
2063TemplateDeclInstantiator::SubstFunctionType(FunctionDecl *D,
2064                              llvm::SmallVectorImpl<ParmVarDecl *> &Params) {
2065  TypeSourceInfo *OldTInfo = D->getTypeSourceInfo();
2066  assert(OldTInfo && "substituting function without type source info");
2067  assert(Params.empty() && "parameter vector is non-empty at start");
2068  TypeSourceInfo *NewTInfo
2069    = SemaRef.SubstFunctionDeclType(OldTInfo, TemplateArgs,
2070                                    D->getTypeSpecStartLoc(),
2071                                    D->getDeclName());
2072  if (!NewTInfo)
2073    return 0;
2074
2075  if (NewTInfo != OldTInfo) {
2076    // Get parameters from the new type info.
2077    TypeLoc OldTL = OldTInfo->getTypeLoc().IgnoreParens();
2078    if (FunctionProtoTypeLoc *OldProtoLoc
2079                                  = dyn_cast<FunctionProtoTypeLoc>(&OldTL)) {
2080      TypeLoc NewTL = NewTInfo->getTypeLoc().IgnoreParens();
2081      FunctionProtoTypeLoc *NewProtoLoc = cast<FunctionProtoTypeLoc>(&NewTL);
2082      assert(NewProtoLoc && "Missing prototype?");
2083      unsigned NewIdx = 0, NumNewParams = NewProtoLoc->getNumArgs();
2084      for (unsigned OldIdx = 0, NumOldParams = OldProtoLoc->getNumArgs();
2085           OldIdx != NumOldParams; ++OldIdx) {
2086        ParmVarDecl *OldParam = OldProtoLoc->getArg(OldIdx);
2087        if (!OldParam->isParameterPack() ||
2088            (NewIdx < NumNewParams &&
2089             NewProtoLoc->getArg(NewIdx)->isParameterPack())) {
2090          // Simple case: normal parameter, or a parameter pack that's
2091          // instantiated to a (still-dependent) parameter pack.
2092          ParmVarDecl *NewParam = NewProtoLoc->getArg(NewIdx++);
2093          Params.push_back(NewParam);
2094          SemaRef.CurrentInstantiationScope->InstantiatedLocal(OldParam,
2095                                                               NewParam);
2096          continue;
2097        }
2098
2099        // Parameter pack: make the instantiation an argument pack.
2100        SemaRef.CurrentInstantiationScope->MakeInstantiatedLocalArgPack(
2101                                                                      OldParam);
2102        unsigned NumArgumentsInExpansion
2103          = SemaRef.getNumArgumentsInExpansion(OldParam->getType(),
2104                                               TemplateArgs);
2105        while (NumArgumentsInExpansion--) {
2106          ParmVarDecl *NewParam = NewProtoLoc->getArg(NewIdx++);
2107          Params.push_back(NewParam);
2108          SemaRef.CurrentInstantiationScope->InstantiatedLocalPackArg(OldParam,
2109                                                                      NewParam);
2110        }
2111      }
2112    }
2113  } else {
2114    // The function type itself was not dependent and therefore no
2115    // substitution occurred. However, we still need to instantiate
2116    // the function parameters themselves.
2117    TypeLoc OldTL = OldTInfo->getTypeLoc().IgnoreParens();
2118    if (FunctionProtoTypeLoc *OldProtoLoc
2119                                    = dyn_cast<FunctionProtoTypeLoc>(&OldTL)) {
2120      for (unsigned i = 0, i_end = OldProtoLoc->getNumArgs(); i != i_end; ++i) {
2121        ParmVarDecl *Parm = VisitParmVarDecl(OldProtoLoc->getArg(i));
2122        if (!Parm)
2123          return 0;
2124        Params.push_back(Parm);
2125      }
2126    }
2127  }
2128  return NewTInfo;
2129}
2130
2131/// \brief Initializes the common fields of an instantiation function
2132/// declaration (New) from the corresponding fields of its template (Tmpl).
2133///
2134/// \returns true if there was an error
2135bool
2136TemplateDeclInstantiator::InitFunctionInstantiation(FunctionDecl *New,
2137                                                    FunctionDecl *Tmpl) {
2138  if (Tmpl->isDeletedAsWritten())
2139    New->setDeletedAsWritten();
2140
2141  // If we are performing substituting explicitly-specified template arguments
2142  // or deduced template arguments into a function template and we reach this
2143  // point, we are now past the point where SFINAE applies and have committed
2144  // to keeping the new function template specialization. We therefore
2145  // convert the active template instantiation for the function template
2146  // into a template instantiation for this specific function template
2147  // specialization, which is not a SFINAE context, so that we diagnose any
2148  // further errors in the declaration itself.
2149  typedef Sema::ActiveTemplateInstantiation ActiveInstType;
2150  ActiveInstType &ActiveInst = SemaRef.ActiveTemplateInstantiations.back();
2151  if (ActiveInst.Kind == ActiveInstType::ExplicitTemplateArgumentSubstitution ||
2152      ActiveInst.Kind == ActiveInstType::DeducedTemplateArgumentSubstitution) {
2153    if (FunctionTemplateDecl *FunTmpl
2154          = dyn_cast<FunctionTemplateDecl>((Decl *)ActiveInst.Entity)) {
2155      assert(FunTmpl->getTemplatedDecl() == Tmpl &&
2156             "Deduction from the wrong function template?");
2157      (void) FunTmpl;
2158      ActiveInst.Kind = ActiveInstType::TemplateInstantiation;
2159      ActiveInst.Entity = reinterpret_cast<uintptr_t>(New);
2160      --SemaRef.NonInstantiationEntries;
2161    }
2162  }
2163
2164  const FunctionProtoType *Proto = Tmpl->getType()->getAs<FunctionProtoType>();
2165  assert(Proto && "Function template without prototype?");
2166
2167  if (Proto->hasExceptionSpec() || Proto->getNoReturnAttr()) {
2168    // The function has an exception specification or a "noreturn"
2169    // attribute. Substitute into each of the exception types.
2170    llvm::SmallVector<QualType, 4> Exceptions;
2171    for (unsigned I = 0, N = Proto->getNumExceptions(); I != N; ++I) {
2172      // FIXME: Poor location information!
2173      if (const PackExpansionType *PackExpansion
2174            = Proto->getExceptionType(I)->getAs<PackExpansionType>()) {
2175        // We have a pack expansion. Instantiate it.
2176        llvm::SmallVector<UnexpandedParameterPack, 2> Unexpanded;
2177        SemaRef.collectUnexpandedParameterPacks(PackExpansion->getPattern(),
2178                                                Unexpanded);
2179        assert(!Unexpanded.empty() &&
2180               "Pack expansion without parameter packs?");
2181
2182        bool Expand = false;
2183        bool RetainExpansion = false;
2184        llvm::Optional<unsigned> NumExpansions
2185                                          = PackExpansion->getNumExpansions();
2186        if (SemaRef.CheckParameterPacksForExpansion(New->getLocation(),
2187                                                    SourceRange(),
2188                                                    Unexpanded.data(),
2189                                                    Unexpanded.size(),
2190                                                    TemplateArgs,
2191                                                    Expand,
2192                                                    RetainExpansion,
2193                                                    NumExpansions))
2194          break;
2195
2196        if (!Expand) {
2197          // We can't expand this pack expansion into separate arguments yet;
2198          // just substitute into the pattern and create a new pack expansion
2199          // type.
2200          Sema::ArgumentPackSubstitutionIndexRAII SubstIndex(SemaRef, -1);
2201          QualType T = SemaRef.SubstType(PackExpansion->getPattern(),
2202                                         TemplateArgs,
2203                                       New->getLocation(), New->getDeclName());
2204          if (T.isNull())
2205            break;
2206
2207          T = SemaRef.Context.getPackExpansionType(T, NumExpansions);
2208          Exceptions.push_back(T);
2209          continue;
2210        }
2211
2212        // Substitute into the pack expansion pattern for each template
2213        bool Invalid = false;
2214        for (unsigned ArgIdx = 0; ArgIdx != *NumExpansions; ++ArgIdx) {
2215          Sema::ArgumentPackSubstitutionIndexRAII SubstIndex(SemaRef, ArgIdx);
2216
2217          QualType T = SemaRef.SubstType(PackExpansion->getPattern(),
2218                                         TemplateArgs,
2219                                       New->getLocation(), New->getDeclName());
2220          if (T.isNull()) {
2221            Invalid = true;
2222            break;
2223          }
2224
2225          Exceptions.push_back(T);
2226        }
2227
2228        if (Invalid)
2229          break;
2230
2231        continue;
2232      }
2233
2234      QualType T
2235        = SemaRef.SubstType(Proto->getExceptionType(I), TemplateArgs,
2236                            New->getLocation(), New->getDeclName());
2237      if (T.isNull() ||
2238          SemaRef.CheckSpecifiedExceptionType(T, New->getLocation()))
2239        continue;
2240
2241      Exceptions.push_back(T);
2242    }
2243    Expr *NoexceptExpr = 0;
2244    if (Expr *OldNoexceptExpr = Proto->getNoexceptExpr()) {
2245      EnterExpressionEvaluationContext Unevaluated(SemaRef, Sema::Unevaluated);
2246      ExprResult E = SemaRef.SubstExpr(OldNoexceptExpr, TemplateArgs);
2247      if (E.isUsable())
2248        NoexceptExpr = E.take();
2249    }
2250
2251    // Rebuild the function type
2252
2253    FunctionProtoType::ExtProtoInfo EPI = Proto->getExtProtoInfo();
2254    EPI.ExceptionSpecType = Proto->getExceptionSpecType();
2255    EPI.NumExceptions = Exceptions.size();
2256    EPI.Exceptions = Exceptions.data();
2257    EPI.NoexceptExpr = NoexceptExpr;
2258    EPI.ExtInfo = Proto->getExtInfo();
2259
2260    const FunctionProtoType *NewProto
2261      = New->getType()->getAs<FunctionProtoType>();
2262    assert(NewProto && "Template instantiation without function prototype?");
2263    New->setType(SemaRef.Context.getFunctionType(NewProto->getResultType(),
2264                                                 NewProto->arg_type_begin(),
2265                                                 NewProto->getNumArgs(),
2266                                                 EPI));
2267  }
2268
2269  SemaRef.InstantiateAttrs(TemplateArgs, Tmpl, New);
2270
2271  return false;
2272}
2273
2274/// \brief Initializes common fields of an instantiated method
2275/// declaration (New) from the corresponding fields of its template
2276/// (Tmpl).
2277///
2278/// \returns true if there was an error
2279bool
2280TemplateDeclInstantiator::InitMethodInstantiation(CXXMethodDecl *New,
2281                                                  CXXMethodDecl *Tmpl) {
2282  if (InitFunctionInstantiation(New, Tmpl))
2283    return true;
2284
2285  New->setAccess(Tmpl->getAccess());
2286  if (Tmpl->isVirtualAsWritten())
2287    New->setVirtualAsWritten(true);
2288
2289  // FIXME: attributes
2290  // FIXME: New needs a pointer to Tmpl
2291  return false;
2292}
2293
2294/// \brief Instantiate the definition of the given function from its
2295/// template.
2296///
2297/// \param PointOfInstantiation the point at which the instantiation was
2298/// required. Note that this is not precisely a "point of instantiation"
2299/// for the function, but it's close.
2300///
2301/// \param Function the already-instantiated declaration of a
2302/// function template specialization or member function of a class template
2303/// specialization.
2304///
2305/// \param Recursive if true, recursively instantiates any functions that
2306/// are required by this instantiation.
2307///
2308/// \param DefinitionRequired if true, then we are performing an explicit
2309/// instantiation where the body of the function is required. Complain if
2310/// there is no such body.
2311void Sema::InstantiateFunctionDefinition(SourceLocation PointOfInstantiation,
2312                                         FunctionDecl *Function,
2313                                         bool Recursive,
2314                                         bool DefinitionRequired) {
2315  if (Function->isInvalidDecl() || Function->isDefined())
2316    return;
2317
2318  // Never instantiate an explicit specialization.
2319  if (Function->getTemplateSpecializationKind() == TSK_ExplicitSpecialization)
2320    return;
2321
2322  // Find the function body that we'll be substituting.
2323  const FunctionDecl *PatternDecl = Function->getTemplateInstantiationPattern();
2324  assert(PatternDecl && "instantiating a non-template");
2325
2326  Stmt *Pattern = PatternDecl->getBody(PatternDecl);
2327  assert(PatternDecl && "template definition is not a template");
2328  if (!Pattern) {
2329    // Try to find a defaulted definition
2330    PatternDecl->isDefined(PatternDecl);
2331  }
2332  assert(PatternDecl && "template definition is not a template");
2333
2334  // Postpone late parsed template instantiations.
2335  if (PatternDecl->isLateTemplateParsed() &&
2336      !LateTemplateParser) {
2337    PendingInstantiations.push_back(
2338      std::make_pair(Function, PointOfInstantiation));
2339    return;
2340  }
2341
2342  // Call the LateTemplateParser callback if there a need to late parse
2343  // a templated function definition.
2344  if (!Pattern && PatternDecl->isLateTemplateParsed() &&
2345      LateTemplateParser) {
2346    LateTemplateParser(OpaqueParser, PatternDecl);
2347    Pattern = PatternDecl->getBody(PatternDecl);
2348  }
2349
2350  if (!Pattern && !PatternDecl->isDefaulted()) {
2351    if (DefinitionRequired) {
2352      if (Function->getPrimaryTemplate())
2353        Diag(PointOfInstantiation,
2354             diag::err_explicit_instantiation_undefined_func_template)
2355          << Function->getPrimaryTemplate();
2356      else
2357        Diag(PointOfInstantiation,
2358             diag::err_explicit_instantiation_undefined_member)
2359          << 1 << Function->getDeclName() << Function->getDeclContext();
2360
2361      if (PatternDecl)
2362        Diag(PatternDecl->getLocation(),
2363             diag::note_explicit_instantiation_here);
2364      Function->setInvalidDecl();
2365    } else if (Function->getTemplateSpecializationKind()
2366                 == TSK_ExplicitInstantiationDefinition) {
2367      PendingInstantiations.push_back(
2368        std::make_pair(Function, PointOfInstantiation));
2369    }
2370
2371    return;
2372  }
2373
2374  // C++0x [temp.explicit]p9:
2375  //   Except for inline functions, other explicit instantiation declarations
2376  //   have the effect of suppressing the implicit instantiation of the entity
2377  //   to which they refer.
2378  if (Function->getTemplateSpecializationKind()
2379        == TSK_ExplicitInstantiationDeclaration &&
2380      !PatternDecl->isInlined())
2381    return;
2382
2383  InstantiatingTemplate Inst(*this, PointOfInstantiation, Function);
2384  if (Inst)
2385    return;
2386
2387  // If we're performing recursive template instantiation, create our own
2388  // queue of pending implicit instantiations that we will instantiate later,
2389  // while we're still within our own instantiation context.
2390  llvm::SmallVector<VTableUse, 16> SavedVTableUses;
2391  std::deque<PendingImplicitInstantiation> SavedPendingInstantiations;
2392  if (Recursive) {
2393    VTableUses.swap(SavedVTableUses);
2394    PendingInstantiations.swap(SavedPendingInstantiations);
2395  }
2396
2397  EnterExpressionEvaluationContext EvalContext(*this,
2398                                               Sema::PotentiallyEvaluated);
2399  ActOnStartOfFunctionDef(0, Function);
2400
2401  // Introduce a new scope where local variable instantiations will be
2402  // recorded, unless we're actually a member function within a local
2403  // class, in which case we need to merge our results with the parent
2404  // scope (of the enclosing function).
2405  bool MergeWithParentScope = false;
2406  if (CXXRecordDecl *Rec = dyn_cast<CXXRecordDecl>(Function->getDeclContext()))
2407    MergeWithParentScope = Rec->isLocalClass();
2408
2409  LocalInstantiationScope Scope(*this, MergeWithParentScope);
2410
2411  // Introduce the instantiated function parameters into the local
2412  // instantiation scope, and set the parameter names to those used
2413  // in the template.
2414  unsigned FParamIdx = 0;
2415  for (unsigned I = 0, N = PatternDecl->getNumParams(); I != N; ++I) {
2416    const ParmVarDecl *PatternParam = PatternDecl->getParamDecl(I);
2417    if (!PatternParam->isParameterPack()) {
2418      // Simple case: not a parameter pack.
2419      assert(FParamIdx < Function->getNumParams());
2420      ParmVarDecl *FunctionParam = Function->getParamDecl(I);
2421      FunctionParam->setDeclName(PatternParam->getDeclName());
2422      Scope.InstantiatedLocal(PatternParam, FunctionParam);
2423      ++FParamIdx;
2424      continue;
2425    }
2426
2427    // Expand the parameter pack.
2428    Scope.MakeInstantiatedLocalArgPack(PatternParam);
2429    for (unsigned NumFParams = Function->getNumParams();
2430         FParamIdx < NumFParams;
2431         ++FParamIdx) {
2432      ParmVarDecl *FunctionParam = Function->getParamDecl(FParamIdx);
2433      FunctionParam->setDeclName(PatternParam->getDeclName());
2434      Scope.InstantiatedLocalPackArg(PatternParam, FunctionParam);
2435    }
2436  }
2437
2438  // Enter the scope of this instantiation. We don't use
2439  // PushDeclContext because we don't have a scope.
2440  Sema::ContextRAII savedContext(*this, Function);
2441
2442  MultiLevelTemplateArgumentList TemplateArgs =
2443    getTemplateInstantiationArgs(Function, 0, false, PatternDecl);
2444
2445  if (PatternDecl->isDefaulted()) {
2446    ActOnFinishFunctionBody(Function, 0, /*IsInstantiation=*/true);
2447
2448    SetDeclDefaulted(Function, PatternDecl->getLocation());
2449  } else {
2450    // If this is a constructor, instantiate the member initializers.
2451    if (const CXXConstructorDecl *Ctor =
2452          dyn_cast<CXXConstructorDecl>(PatternDecl)) {
2453      InstantiateMemInitializers(cast<CXXConstructorDecl>(Function), Ctor,
2454                                 TemplateArgs);
2455    }
2456
2457    // Instantiate the function body.
2458    StmtResult Body = SubstStmt(Pattern, TemplateArgs);
2459
2460    if (Body.isInvalid())
2461      Function->setInvalidDecl();
2462
2463    ActOnFinishFunctionBody(Function, Body.get(),
2464                            /*IsInstantiation=*/true);
2465  }
2466
2467  PerformDependentDiagnostics(PatternDecl, TemplateArgs);
2468
2469  savedContext.pop();
2470
2471  DeclGroupRef DG(Function);
2472  Consumer.HandleTopLevelDecl(DG);
2473
2474  // This class may have local implicit instantiations that need to be
2475  // instantiation within this scope.
2476  PerformPendingInstantiations(/*LocalOnly=*/true);
2477  Scope.Exit();
2478
2479  if (Recursive) {
2480    // Define any pending vtables.
2481    DefineUsedVTables();
2482
2483    // Instantiate any pending implicit instantiations found during the
2484    // instantiation of this template.
2485    PerformPendingInstantiations();
2486
2487    // Restore the set of pending vtables.
2488    assert(VTableUses.empty() &&
2489           "VTableUses should be empty before it is discarded.");
2490    VTableUses.swap(SavedVTableUses);
2491
2492    // Restore the set of pending implicit instantiations.
2493    assert(PendingInstantiations.empty() &&
2494           "PendingInstantiations should be empty before it is discarded.");
2495    PendingInstantiations.swap(SavedPendingInstantiations);
2496  }
2497}
2498
2499/// \brief Instantiate the definition of the given variable from its
2500/// template.
2501///
2502/// \param PointOfInstantiation the point at which the instantiation was
2503/// required. Note that this is not precisely a "point of instantiation"
2504/// for the function, but it's close.
2505///
2506/// \param Var the already-instantiated declaration of a static member
2507/// variable of a class template specialization.
2508///
2509/// \param Recursive if true, recursively instantiates any functions that
2510/// are required by this instantiation.
2511///
2512/// \param DefinitionRequired if true, then we are performing an explicit
2513/// instantiation where an out-of-line definition of the member variable
2514/// is required. Complain if there is no such definition.
2515void Sema::InstantiateStaticDataMemberDefinition(
2516                                          SourceLocation PointOfInstantiation,
2517                                                 VarDecl *Var,
2518                                                 bool Recursive,
2519                                                 bool DefinitionRequired) {
2520  if (Var->isInvalidDecl())
2521    return;
2522
2523  // Find the out-of-line definition of this static data member.
2524  VarDecl *Def = Var->getInstantiatedFromStaticDataMember();
2525  assert(Def && "This data member was not instantiated from a template?");
2526  assert(Def->isStaticDataMember() && "Not a static data member?");
2527  Def = Def->getOutOfLineDefinition();
2528
2529  if (!Def) {
2530    // We did not find an out-of-line definition of this static data member,
2531    // so we won't perform any instantiation. Rather, we rely on the user to
2532    // instantiate this definition (or provide a specialization for it) in
2533    // another translation unit.
2534    if (DefinitionRequired) {
2535      Def = Var->getInstantiatedFromStaticDataMember();
2536      Diag(PointOfInstantiation,
2537           diag::err_explicit_instantiation_undefined_member)
2538        << 2 << Var->getDeclName() << Var->getDeclContext();
2539      Diag(Def->getLocation(), diag::note_explicit_instantiation_here);
2540    } else if (Var->getTemplateSpecializationKind()
2541                 == TSK_ExplicitInstantiationDefinition) {
2542      PendingInstantiations.push_back(
2543        std::make_pair(Var, PointOfInstantiation));
2544    }
2545
2546    return;
2547  }
2548
2549  // Never instantiate an explicit specialization.
2550  if (Var->getTemplateSpecializationKind() == TSK_ExplicitSpecialization)
2551    return;
2552
2553  // C++0x [temp.explicit]p9:
2554  //   Except for inline functions, other explicit instantiation declarations
2555  //   have the effect of suppressing the implicit instantiation of the entity
2556  //   to which they refer.
2557  if (Var->getTemplateSpecializationKind()
2558        == TSK_ExplicitInstantiationDeclaration)
2559    return;
2560
2561  // If we already have a definition, we're done.
2562  if (Var->getDefinition())
2563    return;
2564
2565  InstantiatingTemplate Inst(*this, PointOfInstantiation, Var);
2566  if (Inst)
2567    return;
2568
2569  // If we're performing recursive template instantiation, create our own
2570  // queue of pending implicit instantiations that we will instantiate later,
2571  // while we're still within our own instantiation context.
2572  llvm::SmallVector<VTableUse, 16> SavedVTableUses;
2573  std::deque<PendingImplicitInstantiation> SavedPendingInstantiations;
2574  if (Recursive) {
2575    VTableUses.swap(SavedVTableUses);
2576    PendingInstantiations.swap(SavedPendingInstantiations);
2577  }
2578
2579  // Enter the scope of this instantiation. We don't use
2580  // PushDeclContext because we don't have a scope.
2581  ContextRAII previousContext(*this, Var->getDeclContext());
2582
2583  VarDecl *OldVar = Var;
2584  Var = cast_or_null<VarDecl>(SubstDecl(Def, Var->getDeclContext(),
2585                                        getTemplateInstantiationArgs(Var)));
2586
2587  previousContext.pop();
2588
2589  if (Var) {
2590    MemberSpecializationInfo *MSInfo = OldVar->getMemberSpecializationInfo();
2591    assert(MSInfo && "Missing member specialization information?");
2592    Var->setTemplateSpecializationKind(MSInfo->getTemplateSpecializationKind(),
2593                                       MSInfo->getPointOfInstantiation());
2594    DeclGroupRef DG(Var);
2595    Consumer.HandleTopLevelDecl(DG);
2596  }
2597
2598  if (Recursive) {
2599    // Define any newly required vtables.
2600    DefineUsedVTables();
2601
2602    // Instantiate any pending implicit instantiations found during the
2603    // instantiation of this template.
2604    PerformPendingInstantiations();
2605
2606    // Restore the set of pending vtables.
2607    assert(VTableUses.empty() &&
2608           "VTableUses should be empty before it is discarded, "
2609           "while instantiating static data member.");
2610    VTableUses.swap(SavedVTableUses);
2611
2612    // Restore the set of pending implicit instantiations.
2613    assert(PendingInstantiations.empty() &&
2614           "PendingInstantiations should be empty before it is discarded, "
2615           "while instantiating static data member.");
2616    PendingInstantiations.swap(SavedPendingInstantiations);
2617  }
2618}
2619
2620void
2621Sema::InstantiateMemInitializers(CXXConstructorDecl *New,
2622                                 const CXXConstructorDecl *Tmpl,
2623                           const MultiLevelTemplateArgumentList &TemplateArgs) {
2624
2625  llvm::SmallVector<MemInitTy*, 4> NewInits;
2626  bool AnyErrors = false;
2627
2628  // Instantiate all the initializers.
2629  for (CXXConstructorDecl::init_const_iterator Inits = Tmpl->init_begin(),
2630                                            InitsEnd = Tmpl->init_end();
2631       Inits != InitsEnd; ++Inits) {
2632    CXXCtorInitializer *Init = *Inits;
2633
2634    // Only instantiate written initializers, let Sema re-construct implicit
2635    // ones.
2636    if (!Init->isWritten())
2637      continue;
2638
2639    SourceLocation LParenLoc, RParenLoc;
2640    ASTOwningVector<Expr*> NewArgs(*this);
2641
2642    SourceLocation EllipsisLoc;
2643
2644    if (Init->isPackExpansion()) {
2645      // This is a pack expansion. We should expand it now.
2646      TypeLoc BaseTL = Init->getBaseClassInfo()->getTypeLoc();
2647      llvm::SmallVector<UnexpandedParameterPack, 2> Unexpanded;
2648      collectUnexpandedParameterPacks(BaseTL, Unexpanded);
2649      bool ShouldExpand = false;
2650      bool RetainExpansion = false;
2651      llvm::Optional<unsigned> NumExpansions;
2652      if (CheckParameterPacksForExpansion(Init->getEllipsisLoc(),
2653                                          BaseTL.getSourceRange(),
2654                                          Unexpanded.data(),
2655                                          Unexpanded.size(),
2656                                          TemplateArgs, ShouldExpand,
2657                                          RetainExpansion,
2658                                          NumExpansions)) {
2659        AnyErrors = true;
2660        New->setInvalidDecl();
2661        continue;
2662      }
2663      assert(ShouldExpand && "Partial instantiation of base initializer?");
2664
2665      // Loop over all of the arguments in the argument pack(s),
2666      for (unsigned I = 0; I != *NumExpansions; ++I) {
2667        Sema::ArgumentPackSubstitutionIndexRAII SubstIndex(*this, I);
2668
2669        // Instantiate the initializer.
2670        if (InstantiateInitializer(*this, Init->getInit(), TemplateArgs,
2671                                   LParenLoc, NewArgs, RParenLoc)) {
2672          AnyErrors = true;
2673          break;
2674        }
2675
2676        // Instantiate the base type.
2677        TypeSourceInfo *BaseTInfo = SubstType(Init->getBaseClassInfo(),
2678                                              TemplateArgs,
2679                                              Init->getSourceLocation(),
2680                                              New->getDeclName());
2681        if (!BaseTInfo) {
2682          AnyErrors = true;
2683          break;
2684        }
2685
2686        // Build the initializer.
2687        MemInitResult NewInit = BuildBaseInitializer(BaseTInfo->getType(),
2688                                                     BaseTInfo,
2689                                                     (Expr **)NewArgs.data(),
2690                                                     NewArgs.size(),
2691                                                     Init->getLParenLoc(),
2692                                                     Init->getRParenLoc(),
2693                                                     New->getParent(),
2694                                                     SourceLocation());
2695        if (NewInit.isInvalid()) {
2696          AnyErrors = true;
2697          break;
2698        }
2699
2700        NewInits.push_back(NewInit.get());
2701        NewArgs.clear();
2702      }
2703
2704      continue;
2705    }
2706
2707    // Instantiate the initializer.
2708    if (InstantiateInitializer(*this, Init->getInit(), TemplateArgs,
2709                               LParenLoc, NewArgs, RParenLoc)) {
2710      AnyErrors = true;
2711      continue;
2712    }
2713
2714    MemInitResult NewInit;
2715    if (Init->isBaseInitializer()) {
2716      TypeSourceInfo *BaseTInfo = SubstType(Init->getBaseClassInfo(),
2717                                            TemplateArgs,
2718                                            Init->getSourceLocation(),
2719                                            New->getDeclName());
2720      if (!BaseTInfo) {
2721        AnyErrors = true;
2722        New->setInvalidDecl();
2723        continue;
2724      }
2725
2726      NewInit = BuildBaseInitializer(BaseTInfo->getType(), BaseTInfo,
2727                                     (Expr **)NewArgs.data(),
2728                                     NewArgs.size(),
2729                                     Init->getLParenLoc(),
2730                                     Init->getRParenLoc(),
2731                                     New->getParent(),
2732                                     EllipsisLoc);
2733    } else if (Init->isMemberInitializer()) {
2734      FieldDecl *Member = cast_or_null<FieldDecl>(FindInstantiatedDecl(
2735                                                     Init->getMemberLocation(),
2736                                                     Init->getMember(),
2737                                                     TemplateArgs));
2738      if (!Member) {
2739        AnyErrors = true;
2740        New->setInvalidDecl();
2741        continue;
2742      }
2743
2744      NewInit = BuildMemberInitializer(Member, (Expr **)NewArgs.data(),
2745                                       NewArgs.size(),
2746                                       Init->getSourceLocation(),
2747                                       Init->getLParenLoc(),
2748                                       Init->getRParenLoc());
2749    } else if (Init->isIndirectMemberInitializer()) {
2750      IndirectFieldDecl *IndirectMember =
2751         cast_or_null<IndirectFieldDecl>(FindInstantiatedDecl(
2752                                 Init->getMemberLocation(),
2753                                 Init->getIndirectMember(), TemplateArgs));
2754
2755      if (!IndirectMember) {
2756        AnyErrors = true;
2757        New->setInvalidDecl();
2758        continue;
2759      }
2760
2761      NewInit = BuildMemberInitializer(IndirectMember, (Expr **)NewArgs.data(),
2762                                       NewArgs.size(),
2763                                       Init->getSourceLocation(),
2764                                       Init->getLParenLoc(),
2765                                       Init->getRParenLoc());
2766    }
2767
2768    if (NewInit.isInvalid()) {
2769      AnyErrors = true;
2770      New->setInvalidDecl();
2771    } else {
2772      // FIXME: It would be nice if ASTOwningVector had a release function.
2773      NewArgs.take();
2774
2775      NewInits.push_back((MemInitTy *)NewInit.get());
2776    }
2777  }
2778
2779  // Assign all the initializers to the new constructor.
2780  ActOnMemInitializers(New,
2781                       /*FIXME: ColonLoc */
2782                       SourceLocation(),
2783                       NewInits.data(), NewInits.size(),
2784                       AnyErrors);
2785}
2786
2787// TODO: this could be templated if the various decl types used the
2788// same method name.
2789static bool isInstantiationOf(ClassTemplateDecl *Pattern,
2790                              ClassTemplateDecl *Instance) {
2791  Pattern = Pattern->getCanonicalDecl();
2792
2793  do {
2794    Instance = Instance->getCanonicalDecl();
2795    if (Pattern == Instance) return true;
2796    Instance = Instance->getInstantiatedFromMemberTemplate();
2797  } while (Instance);
2798
2799  return false;
2800}
2801
2802static bool isInstantiationOf(FunctionTemplateDecl *Pattern,
2803                              FunctionTemplateDecl *Instance) {
2804  Pattern = Pattern->getCanonicalDecl();
2805
2806  do {
2807    Instance = Instance->getCanonicalDecl();
2808    if (Pattern == Instance) return true;
2809    Instance = Instance->getInstantiatedFromMemberTemplate();
2810  } while (Instance);
2811
2812  return false;
2813}
2814
2815static bool
2816isInstantiationOf(ClassTemplatePartialSpecializationDecl *Pattern,
2817                  ClassTemplatePartialSpecializationDecl *Instance) {
2818  Pattern
2819    = cast<ClassTemplatePartialSpecializationDecl>(Pattern->getCanonicalDecl());
2820  do {
2821    Instance = cast<ClassTemplatePartialSpecializationDecl>(
2822                                                Instance->getCanonicalDecl());
2823    if (Pattern == Instance)
2824      return true;
2825    Instance = Instance->getInstantiatedFromMember();
2826  } while (Instance);
2827
2828  return false;
2829}
2830
2831static bool isInstantiationOf(CXXRecordDecl *Pattern,
2832                              CXXRecordDecl *Instance) {
2833  Pattern = Pattern->getCanonicalDecl();
2834
2835  do {
2836    Instance = Instance->getCanonicalDecl();
2837    if (Pattern == Instance) return true;
2838    Instance = Instance->getInstantiatedFromMemberClass();
2839  } while (Instance);
2840
2841  return false;
2842}
2843
2844static bool isInstantiationOf(FunctionDecl *Pattern,
2845                              FunctionDecl *Instance) {
2846  Pattern = Pattern->getCanonicalDecl();
2847
2848  do {
2849    Instance = Instance->getCanonicalDecl();
2850    if (Pattern == Instance) return true;
2851    Instance = Instance->getInstantiatedFromMemberFunction();
2852  } while (Instance);
2853
2854  return false;
2855}
2856
2857static bool isInstantiationOf(EnumDecl *Pattern,
2858                              EnumDecl *Instance) {
2859  Pattern = Pattern->getCanonicalDecl();
2860
2861  do {
2862    Instance = Instance->getCanonicalDecl();
2863    if (Pattern == Instance) return true;
2864    Instance = Instance->getInstantiatedFromMemberEnum();
2865  } while (Instance);
2866
2867  return false;
2868}
2869
2870static bool isInstantiationOf(UsingShadowDecl *Pattern,
2871                              UsingShadowDecl *Instance,
2872                              ASTContext &C) {
2873  return C.getInstantiatedFromUsingShadowDecl(Instance) == Pattern;
2874}
2875
2876static bool isInstantiationOf(UsingDecl *Pattern,
2877                              UsingDecl *Instance,
2878                              ASTContext &C) {
2879  return C.getInstantiatedFromUsingDecl(Instance) == Pattern;
2880}
2881
2882static bool isInstantiationOf(UnresolvedUsingValueDecl *Pattern,
2883                              UsingDecl *Instance,
2884                              ASTContext &C) {
2885  return C.getInstantiatedFromUsingDecl(Instance) == Pattern;
2886}
2887
2888static bool isInstantiationOf(UnresolvedUsingTypenameDecl *Pattern,
2889                              UsingDecl *Instance,
2890                              ASTContext &C) {
2891  return C.getInstantiatedFromUsingDecl(Instance) == Pattern;
2892}
2893
2894static bool isInstantiationOfStaticDataMember(VarDecl *Pattern,
2895                                              VarDecl *Instance) {
2896  assert(Instance->isStaticDataMember());
2897
2898  Pattern = Pattern->getCanonicalDecl();
2899
2900  do {
2901    Instance = Instance->getCanonicalDecl();
2902    if (Pattern == Instance) return true;
2903    Instance = Instance->getInstantiatedFromStaticDataMember();
2904  } while (Instance);
2905
2906  return false;
2907}
2908
2909// Other is the prospective instantiation
2910// D is the prospective pattern
2911static bool isInstantiationOf(ASTContext &Ctx, NamedDecl *D, Decl *Other) {
2912  if (D->getKind() != Other->getKind()) {
2913    if (UnresolvedUsingTypenameDecl *UUD
2914          = dyn_cast<UnresolvedUsingTypenameDecl>(D)) {
2915      if (UsingDecl *UD = dyn_cast<UsingDecl>(Other)) {
2916        return isInstantiationOf(UUD, UD, Ctx);
2917      }
2918    }
2919
2920    if (UnresolvedUsingValueDecl *UUD
2921          = dyn_cast<UnresolvedUsingValueDecl>(D)) {
2922      if (UsingDecl *UD = dyn_cast<UsingDecl>(Other)) {
2923        return isInstantiationOf(UUD, UD, Ctx);
2924      }
2925    }
2926
2927    return false;
2928  }
2929
2930  if (CXXRecordDecl *Record = dyn_cast<CXXRecordDecl>(Other))
2931    return isInstantiationOf(cast<CXXRecordDecl>(D), Record);
2932
2933  if (FunctionDecl *Function = dyn_cast<FunctionDecl>(Other))
2934    return isInstantiationOf(cast<FunctionDecl>(D), Function);
2935
2936  if (EnumDecl *Enum = dyn_cast<EnumDecl>(Other))
2937    return isInstantiationOf(cast<EnumDecl>(D), Enum);
2938
2939  if (VarDecl *Var = dyn_cast<VarDecl>(Other))
2940    if (Var->isStaticDataMember())
2941      return isInstantiationOfStaticDataMember(cast<VarDecl>(D), Var);
2942
2943  if (ClassTemplateDecl *Temp = dyn_cast<ClassTemplateDecl>(Other))
2944    return isInstantiationOf(cast<ClassTemplateDecl>(D), Temp);
2945
2946  if (FunctionTemplateDecl *Temp = dyn_cast<FunctionTemplateDecl>(Other))
2947    return isInstantiationOf(cast<FunctionTemplateDecl>(D), Temp);
2948
2949  if (ClassTemplatePartialSpecializationDecl *PartialSpec
2950        = dyn_cast<ClassTemplatePartialSpecializationDecl>(Other))
2951    return isInstantiationOf(cast<ClassTemplatePartialSpecializationDecl>(D),
2952                             PartialSpec);
2953
2954  if (FieldDecl *Field = dyn_cast<FieldDecl>(Other)) {
2955    if (!Field->getDeclName()) {
2956      // This is an unnamed field.
2957      return Ctx.getInstantiatedFromUnnamedFieldDecl(Field) ==
2958        cast<FieldDecl>(D);
2959    }
2960  }
2961
2962  if (UsingDecl *Using = dyn_cast<UsingDecl>(Other))
2963    return isInstantiationOf(cast<UsingDecl>(D), Using, Ctx);
2964
2965  if (UsingShadowDecl *Shadow = dyn_cast<UsingShadowDecl>(Other))
2966    return isInstantiationOf(cast<UsingShadowDecl>(D), Shadow, Ctx);
2967
2968  return D->getDeclName() && isa<NamedDecl>(Other) &&
2969    D->getDeclName() == cast<NamedDecl>(Other)->getDeclName();
2970}
2971
2972template<typename ForwardIterator>
2973static NamedDecl *findInstantiationOf(ASTContext &Ctx,
2974                                      NamedDecl *D,
2975                                      ForwardIterator first,
2976                                      ForwardIterator last) {
2977  for (; first != last; ++first)
2978    if (isInstantiationOf(Ctx, D, *first))
2979      return cast<NamedDecl>(*first);
2980
2981  return 0;
2982}
2983
2984/// \brief Finds the instantiation of the given declaration context
2985/// within the current instantiation.
2986///
2987/// \returns NULL if there was an error
2988DeclContext *Sema::FindInstantiatedContext(SourceLocation Loc, DeclContext* DC,
2989                          const MultiLevelTemplateArgumentList &TemplateArgs) {
2990  if (NamedDecl *D = dyn_cast<NamedDecl>(DC)) {
2991    Decl* ID = FindInstantiatedDecl(Loc, D, TemplateArgs);
2992    return cast_or_null<DeclContext>(ID);
2993  } else return DC;
2994}
2995
2996/// \brief Find the instantiation of the given declaration within the
2997/// current instantiation.
2998///
2999/// This routine is intended to be used when \p D is a declaration
3000/// referenced from within a template, that needs to mapped into the
3001/// corresponding declaration within an instantiation. For example,
3002/// given:
3003///
3004/// \code
3005/// template<typename T>
3006/// struct X {
3007///   enum Kind {
3008///     KnownValue = sizeof(T)
3009///   };
3010///
3011///   bool getKind() const { return KnownValue; }
3012/// };
3013///
3014/// template struct X<int>;
3015/// \endcode
3016///
3017/// In the instantiation of X<int>::getKind(), we need to map the
3018/// EnumConstantDecl for KnownValue (which refers to
3019/// X<T>::<Kind>::KnownValue) to its instantiation
3020/// (X<int>::<Kind>::KnownValue). InstantiateCurrentDeclRef() performs
3021/// this mapping from within the instantiation of X<int>.
3022NamedDecl *Sema::FindInstantiatedDecl(SourceLocation Loc, NamedDecl *D,
3023                          const MultiLevelTemplateArgumentList &TemplateArgs) {
3024  DeclContext *ParentDC = D->getDeclContext();
3025  if (isa<ParmVarDecl>(D) || isa<NonTypeTemplateParmDecl>(D) ||
3026      isa<TemplateTypeParmDecl>(D) || isa<TemplateTemplateParmDecl>(D) ||
3027      (ParentDC->isFunctionOrMethod() && ParentDC->isDependentContext())) {
3028    // D is a local of some kind. Look into the map of local
3029    // declarations to their instantiations.
3030    typedef LocalInstantiationScope::DeclArgumentPack DeclArgumentPack;
3031    llvm::PointerUnion<Decl *, DeclArgumentPack *> *Found
3032      = CurrentInstantiationScope->findInstantiationOf(D);
3033
3034    if (Found) {
3035      if (Decl *FD = Found->dyn_cast<Decl *>())
3036        return cast<NamedDecl>(FD);
3037
3038      unsigned PackIdx = ArgumentPackSubstitutionIndex;
3039      return cast<NamedDecl>((*Found->get<DeclArgumentPack *>())[PackIdx]);
3040    }
3041
3042    // If we didn't find the decl, then we must have a label decl that hasn't
3043    // been found yet.  Lazily instantiate it and return it now.
3044    assert(isa<LabelDecl>(D));
3045
3046    Decl *Inst = SubstDecl(D, CurContext, TemplateArgs);
3047    assert(Inst && "Failed to instantiate label??");
3048
3049    CurrentInstantiationScope->InstantiatedLocal(D, Inst);
3050    return cast<LabelDecl>(Inst);
3051  }
3052
3053  if (CXXRecordDecl *Record = dyn_cast<CXXRecordDecl>(D)) {
3054    if (!Record->isDependentContext())
3055      return D;
3056
3057    // If the RecordDecl is actually the injected-class-name or a
3058    // "templated" declaration for a class template, class template
3059    // partial specialization, or a member class of a class template,
3060    // substitute into the injected-class-name of the class template
3061    // or partial specialization to find the new DeclContext.
3062    QualType T;
3063    ClassTemplateDecl *ClassTemplate = Record->getDescribedClassTemplate();
3064
3065    if (ClassTemplate) {
3066      T = ClassTemplate->getInjectedClassNameSpecialization();
3067    } else if (ClassTemplatePartialSpecializationDecl *PartialSpec
3068                 = dyn_cast<ClassTemplatePartialSpecializationDecl>(Record)) {
3069      ClassTemplate = PartialSpec->getSpecializedTemplate();
3070
3071      // If we call SubstType with an InjectedClassNameType here we
3072      // can end up in an infinite loop.
3073      T = Context.getTypeDeclType(Record);
3074      assert(isa<InjectedClassNameType>(T) &&
3075             "type of partial specialization is not an InjectedClassNameType");
3076      T = cast<InjectedClassNameType>(T)->getInjectedSpecializationType();
3077    }
3078
3079    if (!T.isNull()) {
3080      // Substitute into the injected-class-name to get the type
3081      // corresponding to the instantiation we want, which may also be
3082      // the current instantiation (if we're in a template
3083      // definition). This substitution should never fail, since we
3084      // know we can instantiate the injected-class-name or we
3085      // wouldn't have gotten to the injected-class-name!
3086
3087      // FIXME: Can we use the CurrentInstantiationScope to avoid this
3088      // extra instantiation in the common case?
3089      T = SubstType(T, TemplateArgs, Loc, DeclarationName());
3090      assert(!T.isNull() && "Instantiation of injected-class-name cannot fail.");
3091
3092      if (!T->isDependentType()) {
3093        assert(T->isRecordType() && "Instantiation must produce a record type");
3094        return T->getAs<RecordType>()->getDecl();
3095      }
3096
3097      // We are performing "partial" template instantiation to create
3098      // the member declarations for the members of a class template
3099      // specialization. Therefore, D is actually referring to something
3100      // in the current instantiation. Look through the current
3101      // context, which contains actual instantiations, to find the
3102      // instantiation of the "current instantiation" that D refers
3103      // to.
3104      bool SawNonDependentContext = false;
3105      for (DeclContext *DC = CurContext; !DC->isFileContext();
3106           DC = DC->getParent()) {
3107        if (ClassTemplateSpecializationDecl *Spec
3108                          = dyn_cast<ClassTemplateSpecializationDecl>(DC))
3109          if (isInstantiationOf(ClassTemplate,
3110                                Spec->getSpecializedTemplate()))
3111            return Spec;
3112
3113        if (!DC->isDependentContext())
3114          SawNonDependentContext = true;
3115      }
3116
3117      // We're performing "instantiation" of a member of the current
3118      // instantiation while we are type-checking the
3119      // definition. Compute the declaration context and return that.
3120      assert(!SawNonDependentContext &&
3121             "No dependent context while instantiating record");
3122      DeclContext *DC = computeDeclContext(T);
3123      assert(DC &&
3124             "Unable to find declaration for the current instantiation");
3125      return cast<CXXRecordDecl>(DC);
3126    }
3127
3128    // Fall through to deal with other dependent record types (e.g.,
3129    // anonymous unions in class templates).
3130  }
3131
3132  if (!ParentDC->isDependentContext())
3133    return D;
3134
3135  ParentDC = FindInstantiatedContext(Loc, ParentDC, TemplateArgs);
3136  if (!ParentDC)
3137    return 0;
3138
3139  if (ParentDC != D->getDeclContext()) {
3140    // We performed some kind of instantiation in the parent context,
3141    // so now we need to look into the instantiated parent context to
3142    // find the instantiation of the declaration D.
3143
3144    // If our context used to be dependent, we may need to instantiate
3145    // it before performing lookup into that context.
3146    bool IsBeingInstantiated = false;
3147    if (CXXRecordDecl *Spec = dyn_cast<CXXRecordDecl>(ParentDC)) {
3148      if (!Spec->isDependentContext()) {
3149        QualType T = Context.getTypeDeclType(Spec);
3150        const RecordType *Tag = T->getAs<RecordType>();
3151        assert(Tag && "type of non-dependent record is not a RecordType");
3152        if (Tag->isBeingDefined())
3153          IsBeingInstantiated = true;
3154        if (!Tag->isBeingDefined() &&
3155            RequireCompleteType(Loc, T, diag::err_incomplete_type))
3156          return 0;
3157
3158        ParentDC = Tag->getDecl();
3159      }
3160    }
3161
3162    NamedDecl *Result = 0;
3163    if (D->getDeclName()) {
3164      DeclContext::lookup_result Found = ParentDC->lookup(D->getDeclName());
3165      Result = findInstantiationOf(Context, D, Found.first, Found.second);
3166    } else {
3167      // Since we don't have a name for the entity we're looking for,
3168      // our only option is to walk through all of the declarations to
3169      // find that name. This will occur in a few cases:
3170      //
3171      //   - anonymous struct/union within a template
3172      //   - unnamed class/struct/union/enum within a template
3173      //
3174      // FIXME: Find a better way to find these instantiations!
3175      Result = findInstantiationOf(Context, D,
3176                                   ParentDC->decls_begin(),
3177                                   ParentDC->decls_end());
3178    }
3179
3180    if (!Result) {
3181      if (isa<UsingShadowDecl>(D)) {
3182        // UsingShadowDecls can instantiate to nothing because of using hiding.
3183      } else if (Diags.hasErrorOccurred()) {
3184        // We've already complained about something, so most likely this
3185        // declaration failed to instantiate. There's no point in complaining
3186        // further, since this is normal in invalid code.
3187      } else if (IsBeingInstantiated) {
3188        // The class in which this member exists is currently being
3189        // instantiated, and we haven't gotten around to instantiating this
3190        // member yet. This can happen when the code uses forward declarations
3191        // of member classes, and introduces ordering dependencies via
3192        // template instantiation.
3193        Diag(Loc, diag::err_member_not_yet_instantiated)
3194          << D->getDeclName()
3195          << Context.getTypeDeclType(cast<CXXRecordDecl>(ParentDC));
3196        Diag(D->getLocation(), diag::note_non_instantiated_member_here);
3197      } else {
3198        // We should have found something, but didn't.
3199        llvm_unreachable("Unable to find instantiation of declaration!");
3200      }
3201    }
3202
3203    D = Result;
3204  }
3205
3206  return D;
3207}
3208
3209/// \brief Performs template instantiation for all implicit template
3210/// instantiations we have seen until this point.
3211void Sema::PerformPendingInstantiations(bool LocalOnly) {
3212  while (!PendingLocalImplicitInstantiations.empty() ||
3213         (!LocalOnly && !PendingInstantiations.empty())) {
3214    PendingImplicitInstantiation Inst;
3215
3216    if (PendingLocalImplicitInstantiations.empty()) {
3217      Inst = PendingInstantiations.front();
3218      PendingInstantiations.pop_front();
3219    } else {
3220      Inst = PendingLocalImplicitInstantiations.front();
3221      PendingLocalImplicitInstantiations.pop_front();
3222    }
3223
3224    // Instantiate function definitions
3225    if (FunctionDecl *Function = dyn_cast<FunctionDecl>(Inst.first)) {
3226      PrettyDeclStackTraceEntry CrashInfo(*this, Function, SourceLocation(),
3227                                          "instantiating function definition");
3228      bool DefinitionRequired = Function->getTemplateSpecializationKind() ==
3229                                TSK_ExplicitInstantiationDefinition;
3230      InstantiateFunctionDefinition(/*FIXME:*/Inst.second, Function, true,
3231                                    DefinitionRequired);
3232      continue;
3233    }
3234
3235    // Instantiate static data member definitions.
3236    VarDecl *Var = cast<VarDecl>(Inst.first);
3237    assert(Var->isStaticDataMember() && "Not a static data member?");
3238
3239    // Don't try to instantiate declarations if the most recent redeclaration
3240    // is invalid.
3241    if (Var->getMostRecentDeclaration()->isInvalidDecl())
3242      continue;
3243
3244    // Check if the most recent declaration has changed the specialization kind
3245    // and removed the need for implicit instantiation.
3246    switch (Var->getMostRecentDeclaration()->getTemplateSpecializationKind()) {
3247    case TSK_Undeclared:
3248      assert(false && "Cannot instantitiate an undeclared specialization.");
3249    case TSK_ExplicitInstantiationDeclaration:
3250    case TSK_ExplicitSpecialization:
3251      continue;  // No longer need to instantiate this type.
3252    case TSK_ExplicitInstantiationDefinition:
3253      // We only need an instantiation if the pending instantiation *is* the
3254      // explicit instantiation.
3255      if (Var != Var->getMostRecentDeclaration()) continue;
3256    case TSK_ImplicitInstantiation:
3257      break;
3258    }
3259
3260    PrettyDeclStackTraceEntry CrashInfo(*this, Var, Var->getLocation(),
3261                                        "instantiating static data member "
3262                                        "definition");
3263
3264    bool DefinitionRequired = Var->getTemplateSpecializationKind() ==
3265                              TSK_ExplicitInstantiationDefinition;
3266    InstantiateStaticDataMemberDefinition(/*FIXME:*/Inst.second, Var, true,
3267                                          DefinitionRequired);
3268  }
3269}
3270
3271void Sema::PerformDependentDiagnostics(const DeclContext *Pattern,
3272                       const MultiLevelTemplateArgumentList &TemplateArgs) {
3273  for (DeclContext::ddiag_iterator I = Pattern->ddiag_begin(),
3274         E = Pattern->ddiag_end(); I != E; ++I) {
3275    DependentDiagnostic *DD = *I;
3276
3277    switch (DD->getKind()) {
3278    case DependentDiagnostic::Access:
3279      HandleDependentAccessCheck(*DD, TemplateArgs);
3280      break;
3281    }
3282  }
3283}
3284