SemaTemplateInstantiateDecl.cpp revision 56fb926c93786739cfd0867e7ada31ace3bda946 
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::VisitTypedefDecl(TypedefDecl *D) {
132  bool Invalid = false;
133  TypeSourceInfo *DI = D->getTypeSourceInfo();
134  if (DI->getType()->isDependentType() ||
135      DI->getType()->isVariablyModifiedType()) {
136    DI = SemaRef.SubstType(DI, TemplateArgs,
137                           D->getLocation(), D->getDeclName());
138    if (!DI) {
139      Invalid = true;
140      DI = SemaRef.Context.getTrivialTypeSourceInfo(SemaRef.Context.IntTy);
141    }
142  } else {
143    SemaRef.MarkDeclarationsReferencedInType(D->getLocation(), DI->getType());
144  }
145
146  // Create the new typedef
147  TypedefDecl *Typedef
148    = TypedefDecl::Create(SemaRef.Context, Owner, D->getLocStart(),
149                          D->getLocation(), D->getIdentifier(), DI);
150  if (Invalid)
151    Typedef->setInvalidDecl();
152
153  // If the old typedef was the name for linkage purposes of an anonymous
154  // tag decl, re-establish that relationship for the new typedef.
155  if (const TagType *oldTagType = D->getUnderlyingType()->getAs<TagType>()) {
156    TagDecl *oldTag = oldTagType->getDecl();
157    if (oldTag->getTypedefForAnonDecl() == D) {
158      TagDecl *newTag = DI->getType()->castAs<TagType>()->getDecl();
159      assert(!newTag->getIdentifier() && !newTag->getTypedefForAnonDecl());
160      newTag->setTypedefForAnonDecl(Typedef);
161    }
162  }
163
164  if (TypedefDecl *Prev = D->getPreviousDeclaration()) {
165    NamedDecl *InstPrev = SemaRef.FindInstantiatedDecl(D->getLocation(), Prev,
166                                                       TemplateArgs);
167    if (!InstPrev)
168      return 0;
169
170    Typedef->setPreviousDeclaration(cast<TypedefDecl>(InstPrev));
171  }
172
173  SemaRef.InstantiateAttrs(TemplateArgs, D, Typedef);
174
175  Typedef->setAccess(D->getAccess());
176  Owner->addDecl(Typedef);
177
178  return Typedef;
179}
180
181/// \brief Instantiate an initializer, breaking it into separate
182/// initialization arguments.
183///
184/// \param S The semantic analysis object.
185///
186/// \param Init The initializer to instantiate.
187///
188/// \param TemplateArgs Template arguments to be substituted into the
189/// initializer.
190///
191/// \param NewArgs Will be filled in with the instantiation arguments.
192///
193/// \returns true if an error occurred, false otherwise
194static bool InstantiateInitializer(Sema &S, Expr *Init,
195                            const MultiLevelTemplateArgumentList &TemplateArgs,
196                                   SourceLocation &LParenLoc,
197                                   ASTOwningVector<Expr*> &NewArgs,
198                                   SourceLocation &RParenLoc) {
199  NewArgs.clear();
200  LParenLoc = SourceLocation();
201  RParenLoc = SourceLocation();
202
203  if (!Init)
204    return false;
205
206  if (ExprWithCleanups *ExprTemp = dyn_cast<ExprWithCleanups>(Init))
207    Init = ExprTemp->getSubExpr();
208
209  while (CXXBindTemporaryExpr *Binder = dyn_cast<CXXBindTemporaryExpr>(Init))
210    Init = Binder->getSubExpr();
211
212  if (ImplicitCastExpr *ICE = dyn_cast<ImplicitCastExpr>(Init))
213    Init = ICE->getSubExprAsWritten();
214
215  if (ParenListExpr *ParenList = dyn_cast<ParenListExpr>(Init)) {
216    LParenLoc = ParenList->getLParenLoc();
217    RParenLoc = ParenList->getRParenLoc();
218    return S.SubstExprs(ParenList->getExprs(), ParenList->getNumExprs(),
219                        true, TemplateArgs, NewArgs);
220  }
221
222  if (CXXConstructExpr *Construct = dyn_cast<CXXConstructExpr>(Init)) {
223    if (!isa<CXXTemporaryObjectExpr>(Construct)) {
224      if (S.SubstExprs(Construct->getArgs(), Construct->getNumArgs(), true,
225                       TemplateArgs, NewArgs))
226        return true;
227
228      // FIXME: Fake locations!
229      LParenLoc = S.PP.getLocForEndOfToken(Init->getLocStart());
230      RParenLoc = LParenLoc;
231      return false;
232    }
233  }
234
235  ExprResult Result = S.SubstExpr(Init, TemplateArgs);
236  if (Result.isInvalid())
237    return true;
238
239  NewArgs.push_back(Result.takeAs<Expr>());
240  return false;
241}
242
243Decl *TemplateDeclInstantiator::VisitVarDecl(VarDecl *D) {
244  // If this is the variable for an anonymous struct or union,
245  // instantiate the anonymous struct/union type first.
246  if (const RecordType *RecordTy = D->getType()->getAs<RecordType>())
247    if (RecordTy->getDecl()->isAnonymousStructOrUnion())
248      if (!VisitCXXRecordDecl(cast<CXXRecordDecl>(RecordTy->getDecl())))
249        return 0;
250
251  // Do substitution on the type of the declaration
252  TypeSourceInfo *DI = SemaRef.SubstType(D->getTypeSourceInfo(),
253                                         TemplateArgs,
254                                         D->getTypeSpecStartLoc(),
255                                         D->getDeclName());
256  if (!DI)
257    return 0;
258
259  if (DI->getType()->isFunctionType()) {
260    SemaRef.Diag(D->getLocation(), diag::err_variable_instantiates_to_function)
261      << D->isStaticDataMember() << DI->getType();
262    return 0;
263  }
264
265  // Build the instantiated declaration
266  VarDecl *Var = VarDecl::Create(SemaRef.Context, Owner,
267                                 D->getInnerLocStart(),
268                                 D->getLocation(), D->getIdentifier(),
269                                 DI->getType(), DI,
270                                 D->getStorageClass(),
271                                 D->getStorageClassAsWritten());
272  Var->setThreadSpecified(D->isThreadSpecified());
273  Var->setCXXDirectInitializer(D->hasCXXDirectInitializer());
274
275  // Substitute the nested name specifier, if any.
276  if (SubstQualifier(D, Var))
277    return 0;
278
279  // If we are instantiating a static data member defined
280  // out-of-line, the instantiation will have the same lexical
281  // context (which will be a namespace scope) as the template.
282  if (D->isOutOfLine())
283    Var->setLexicalDeclContext(D->getLexicalDeclContext());
284
285  Var->setAccess(D->getAccess());
286
287  if (!D->isStaticDataMember())
288    Var->setUsed(D->isUsed(false));
289
290  // FIXME: In theory, we could have a previous declaration for variables that
291  // are not static data members.
292  bool Redeclaration = false;
293  // FIXME: having to fake up a LookupResult is dumb.
294  LookupResult Previous(SemaRef, Var->getDeclName(), Var->getLocation(),
295                        Sema::LookupOrdinaryName, Sema::ForRedeclaration);
296  if (D->isStaticDataMember())
297    SemaRef.LookupQualifiedName(Previous, Owner, false);
298  SemaRef.CheckVariableDeclaration(Var, Previous, Redeclaration);
299
300  if (D->isOutOfLine()) {
301    if (!D->isStaticDataMember())
302      D->getLexicalDeclContext()->addDecl(Var);
303    Owner->makeDeclVisibleInContext(Var);
304  } else {
305    Owner->addDecl(Var);
306    if (Owner->isFunctionOrMethod())
307      SemaRef.CurrentInstantiationScope->InstantiatedLocal(D, Var);
308  }
309  SemaRef.InstantiateAttrs(TemplateArgs, D, Var);
310
311  // Link instantiations of static data members back to the template from
312  // which they were instantiated.
313  if (Var->isStaticDataMember())
314    SemaRef.Context.setInstantiatedFromStaticDataMember(Var, D,
315                                                     TSK_ImplicitInstantiation);
316
317  if (Var->getAnyInitializer()) {
318    // We already have an initializer in the class.
319  } else if (D->getInit()) {
320    if (Var->isStaticDataMember() && !D->isOutOfLine())
321      SemaRef.PushExpressionEvaluationContext(Sema::Unevaluated);
322    else
323      SemaRef.PushExpressionEvaluationContext(Sema::PotentiallyEvaluated);
324
325    // Instantiate the initializer.
326    SourceLocation LParenLoc, RParenLoc;
327    ASTOwningVector<Expr*> InitArgs(SemaRef);
328    if (!InstantiateInitializer(SemaRef, D->getInit(), TemplateArgs, LParenLoc,
329                                InitArgs, RParenLoc)) {
330      bool TypeMayContainAuto = true;
331      // Attach the initializer to the declaration, if we have one.
332      if (InitArgs.size() == 0)
333        SemaRef.ActOnUninitializedDecl(Var, TypeMayContainAuto);
334      else if (D->hasCXXDirectInitializer()) {
335        // Add the direct initializer to the declaration.
336        SemaRef.AddCXXDirectInitializerToDecl(Var,
337                                              LParenLoc,
338                                              move_arg(InitArgs),
339                                              RParenLoc,
340                                              TypeMayContainAuto);
341      } else {
342        assert(InitArgs.size() == 1);
343        Expr *Init = InitArgs.take()[0];
344        SemaRef.AddInitializerToDecl(Var, Init, false, TypeMayContainAuto);
345      }
346    } else {
347      // FIXME: Not too happy about invalidating the declaration
348      // because of a bogus initializer.
349      Var->setInvalidDecl();
350    }
351
352    SemaRef.PopExpressionEvaluationContext();
353  } else if (!Var->isStaticDataMember() || Var->isOutOfLine())
354    SemaRef.ActOnUninitializedDecl(Var, false);
355
356  // Diagnose unused local variables.
357  if (!Var->isInvalidDecl() && Owner->isFunctionOrMethod() && !Var->isUsed())
358    SemaRef.DiagnoseUnusedDecl(Var);
359
360  return Var;
361}
362
363Decl *TemplateDeclInstantiator::VisitAccessSpecDecl(AccessSpecDecl *D) {
364  AccessSpecDecl* AD
365    = AccessSpecDecl::Create(SemaRef.Context, D->getAccess(), Owner,
366                             D->getAccessSpecifierLoc(), D->getColonLoc());
367  Owner->addHiddenDecl(AD);
368  return AD;
369}
370
371Decl *TemplateDeclInstantiator::VisitFieldDecl(FieldDecl *D) {
372  bool Invalid = false;
373  TypeSourceInfo *DI = D->getTypeSourceInfo();
374  if (DI->getType()->isDependentType() ||
375      DI->getType()->isVariablyModifiedType())  {
376    DI = SemaRef.SubstType(DI, TemplateArgs,
377                           D->getLocation(), D->getDeclName());
378    if (!DI) {
379      DI = D->getTypeSourceInfo();
380      Invalid = true;
381    } else if (DI->getType()->isFunctionType()) {
382      // C++ [temp.arg.type]p3:
383      //   If a declaration acquires a function type through a type
384      //   dependent on a template-parameter and this causes a
385      //   declaration that does not use the syntactic form of a
386      //   function declarator to have function type, the program is
387      //   ill-formed.
388      SemaRef.Diag(D->getLocation(), diag::err_field_instantiates_to_function)
389        << DI->getType();
390      Invalid = true;
391    }
392  } else {
393    SemaRef.MarkDeclarationsReferencedInType(D->getLocation(), DI->getType());
394  }
395
396  Expr *BitWidth = D->getBitWidth();
397  if (Invalid)
398    BitWidth = 0;
399  else if (BitWidth) {
400    // The bit-width expression is not potentially evaluated.
401    EnterExpressionEvaluationContext Unevaluated(SemaRef, Sema::Unevaluated);
402
403    ExprResult InstantiatedBitWidth
404      = SemaRef.SubstExpr(BitWidth, TemplateArgs);
405    if (InstantiatedBitWidth.isInvalid()) {
406      Invalid = true;
407      BitWidth = 0;
408    } else
409      BitWidth = InstantiatedBitWidth.takeAs<Expr>();
410  }
411
412  FieldDecl *Field = SemaRef.CheckFieldDecl(D->getDeclName(),
413                                            DI->getType(), DI,
414                                            cast<RecordDecl>(Owner),
415                                            D->getLocation(),
416                                            D->isMutable(),
417                                            BitWidth,
418                                            D->getTypeSpecStartLoc(),
419                                            D->getAccess(),
420                                            0);
421  if (!Field) {
422    cast<Decl>(Owner)->setInvalidDecl();
423    return 0;
424  }
425
426  SemaRef.InstantiateAttrs(TemplateArgs, D, Field);
427
428  if (Invalid)
429    Field->setInvalidDecl();
430
431  if (!Field->getDeclName()) {
432    // Keep track of where this decl came from.
433    SemaRef.Context.setInstantiatedFromUnnamedFieldDecl(Field, D);
434  }
435  if (CXXRecordDecl *Parent= dyn_cast<CXXRecordDecl>(Field->getDeclContext())) {
436    if (Parent->isAnonymousStructOrUnion() &&
437        Parent->getRedeclContext()->isFunctionOrMethod())
438      SemaRef.CurrentInstantiationScope->InstantiatedLocal(D, Field);
439  }
440
441  Field->setImplicit(D->isImplicit());
442  Field->setAccess(D->getAccess());
443  Owner->addDecl(Field);
444
445  return Field;
446}
447
448Decl *TemplateDeclInstantiator::VisitIndirectFieldDecl(IndirectFieldDecl *D) {
449  NamedDecl **NamedChain =
450    new (SemaRef.Context)NamedDecl*[D->getChainingSize()];
451
452  int i = 0;
453  for (IndirectFieldDecl::chain_iterator PI =
454       D->chain_begin(), PE = D->chain_end();
455       PI != PE; ++PI) {
456    NamedDecl *Next = SemaRef.FindInstantiatedDecl(D->getLocation(), *PI,
457                                              TemplateArgs);
458    if (!Next)
459      return 0;
460
461    NamedChain[i++] = Next;
462  }
463
464  QualType T = cast<FieldDecl>(NamedChain[i-1])->getType();
465  IndirectFieldDecl* IndirectField
466    = IndirectFieldDecl::Create(SemaRef.Context, Owner, D->getLocation(),
467                                D->getIdentifier(), T,
468                                NamedChain, D->getChainingSize());
469
470
471  IndirectField->setImplicit(D->isImplicit());
472  IndirectField->setAccess(D->getAccess());
473  Owner->addDecl(IndirectField);
474  return IndirectField;
475}
476
477Decl *TemplateDeclInstantiator::VisitFriendDecl(FriendDecl *D) {
478  // Handle friend type expressions by simply substituting template
479  // parameters into the pattern type and checking the result.
480  if (TypeSourceInfo *Ty = D->getFriendType()) {
481    TypeSourceInfo *InstTy =
482      SemaRef.SubstType(Ty, TemplateArgs,
483                        D->getLocation(), DeclarationName());
484    if (!InstTy)
485      return 0;
486
487    FriendDecl *FD = SemaRef.CheckFriendTypeDecl(D->getFriendLoc(), InstTy);
488    if (!FD)
489      return 0;
490
491    FD->setAccess(AS_public);
492    FD->setUnsupportedFriend(D->isUnsupportedFriend());
493    Owner->addDecl(FD);
494    return FD;
495  }
496
497  NamedDecl *ND = D->getFriendDecl();
498  assert(ND && "friend decl must be a decl or a type!");
499
500  // All of the Visit implementations for the various potential friend
501  // declarations have to be carefully written to work for friend
502  // objects, with the most important detail being that the target
503  // decl should almost certainly not be placed in Owner.
504  Decl *NewND = Visit(ND);
505  if (!NewND) return 0;
506
507  FriendDecl *FD =
508    FriendDecl::Create(SemaRef.Context, Owner, D->getLocation(),
509                       cast<NamedDecl>(NewND), D->getFriendLoc());
510  FD->setAccess(AS_public);
511  FD->setUnsupportedFriend(D->isUnsupportedFriend());
512  Owner->addDecl(FD);
513  return FD;
514}
515
516Decl *TemplateDeclInstantiator::VisitStaticAssertDecl(StaticAssertDecl *D) {
517  Expr *AssertExpr = D->getAssertExpr();
518
519  // The expression in a static assertion is not potentially evaluated.
520  EnterExpressionEvaluationContext Unevaluated(SemaRef, Sema::Unevaluated);
521
522  ExprResult InstantiatedAssertExpr
523    = SemaRef.SubstExpr(AssertExpr, TemplateArgs);
524  if (InstantiatedAssertExpr.isInvalid())
525    return 0;
526
527  ExprResult Message(D->getMessage());
528  D->getMessage();
529  return SemaRef.ActOnStaticAssertDeclaration(D->getLocation(),
530                                              InstantiatedAssertExpr.get(),
531                                              Message.get(),
532                                              D->getRParenLoc());
533}
534
535Decl *TemplateDeclInstantiator::VisitEnumDecl(EnumDecl *D) {
536  EnumDecl *Enum = EnumDecl::Create(SemaRef.Context, Owner, D->getLocStart(),
537                                    D->getLocation(), D->getIdentifier(),
538                                    /*PrevDecl=*/0, D->isScoped(),
539                                    D->isScopedUsingClassTag(), D->isFixed());
540  if (D->isFixed()) {
541    if (TypeSourceInfo* TI = D->getIntegerTypeSourceInfo()) {
542      // If we have type source information for the underlying type, it means it
543      // has been explicitly set by the user. Perform substitution on it before
544      // moving on.
545      SourceLocation UnderlyingLoc = TI->getTypeLoc().getBeginLoc();
546      Enum->setIntegerTypeSourceInfo(SemaRef.SubstType(TI,
547                                                       TemplateArgs,
548                                                       UnderlyingLoc,
549                                                       DeclarationName()));
550
551      if (!Enum->getIntegerTypeSourceInfo())
552        Enum->setIntegerType(SemaRef.Context.IntTy);
553    }
554    else {
555      assert(!D->getIntegerType()->isDependentType()
556             && "Dependent type without type source info");
557      Enum->setIntegerType(D->getIntegerType());
558    }
559  }
560
561  SemaRef.InstantiateAttrs(TemplateArgs, D, Enum);
562
563  Enum->setInstantiationOfMemberEnum(D);
564  Enum->setAccess(D->getAccess());
565  if (SubstQualifier(D, Enum)) return 0;
566  Owner->addDecl(Enum);
567  Enum->startDefinition();
568
569  if (D->getDeclContext()->isFunctionOrMethod())
570    SemaRef.CurrentInstantiationScope->InstantiatedLocal(D, Enum);
571
572  llvm::SmallVector<Decl*, 4> Enumerators;
573
574  EnumConstantDecl *LastEnumConst = 0;
575  for (EnumDecl::enumerator_iterator EC = D->enumerator_begin(),
576         ECEnd = D->enumerator_end();
577       EC != ECEnd; ++EC) {
578    // The specified value for the enumerator.
579    ExprResult Value = SemaRef.Owned((Expr *)0);
580    if (Expr *UninstValue = EC->getInitExpr()) {
581      // The enumerator's value expression is not potentially evaluated.
582      EnterExpressionEvaluationContext Unevaluated(SemaRef,
583                                                   Sema::Unevaluated);
584
585      Value = SemaRef.SubstExpr(UninstValue, TemplateArgs);
586    }
587
588    // Drop the initial value and continue.
589    bool isInvalid = false;
590    if (Value.isInvalid()) {
591      Value = SemaRef.Owned((Expr *)0);
592      isInvalid = true;
593    }
594
595    EnumConstantDecl *EnumConst
596      = SemaRef.CheckEnumConstant(Enum, LastEnumConst,
597                                  EC->getLocation(), EC->getIdentifier(),
598                                  Value.get());
599
600    if (isInvalid) {
601      if (EnumConst)
602        EnumConst->setInvalidDecl();
603      Enum->setInvalidDecl();
604    }
605
606    if (EnumConst) {
607      SemaRef.InstantiateAttrs(TemplateArgs, *EC, EnumConst);
608
609      EnumConst->setAccess(Enum->getAccess());
610      Enum->addDecl(EnumConst);
611      Enumerators.push_back(EnumConst);
612      LastEnumConst = EnumConst;
613
614      if (D->getDeclContext()->isFunctionOrMethod()) {
615        // If the enumeration is within a function or method, record the enum
616        // constant as a local.
617        SemaRef.CurrentInstantiationScope->InstantiatedLocal(*EC, EnumConst);
618      }
619    }
620  }
621
622  // FIXME: Fixup LBraceLoc and RBraceLoc
623  // FIXME: Empty Scope and AttributeList (required to handle attribute packed).
624  SemaRef.ActOnEnumBody(Enum->getLocation(), SourceLocation(), SourceLocation(),
625                        Enum,
626                        Enumerators.data(), Enumerators.size(),
627                        0, 0);
628
629  return Enum;
630}
631
632Decl *TemplateDeclInstantiator::VisitEnumConstantDecl(EnumConstantDecl *D) {
633  assert(false && "EnumConstantDecls can only occur within EnumDecls.");
634  return 0;
635}
636
637Decl *TemplateDeclInstantiator::VisitClassTemplateDecl(ClassTemplateDecl *D) {
638  bool isFriend = (D->getFriendObjectKind() != Decl::FOK_None);
639
640  // Create a local instantiation scope for this class template, which
641  // will contain the instantiations of the template parameters.
642  LocalInstantiationScope Scope(SemaRef);
643  TemplateParameterList *TempParams = D->getTemplateParameters();
644  TemplateParameterList *InstParams = SubstTemplateParams(TempParams);
645  if (!InstParams)
646    return NULL;
647
648  CXXRecordDecl *Pattern = D->getTemplatedDecl();
649
650  // Instantiate the qualifier.  We have to do this first in case
651  // we're a friend declaration, because if we are then we need to put
652  // the new declaration in the appropriate context.
653  NestedNameSpecifierLoc QualifierLoc = Pattern->getQualifierLoc();
654  if (QualifierLoc) {
655    QualifierLoc = SemaRef.SubstNestedNameSpecifierLoc(QualifierLoc,
656                                                       TemplateArgs);
657    if (!QualifierLoc)
658      return 0;
659  }
660
661  CXXRecordDecl *PrevDecl = 0;
662  ClassTemplateDecl *PrevClassTemplate = 0;
663
664  if (!isFriend && Pattern->getPreviousDeclaration()) {
665    DeclContext::lookup_result Found = Owner->lookup(Pattern->getDeclName());
666    if (Found.first != Found.second) {
667      PrevClassTemplate = dyn_cast<ClassTemplateDecl>(*Found.first);
668      if (PrevClassTemplate)
669        PrevDecl = PrevClassTemplate->getTemplatedDecl();
670    }
671  }
672
673  // If this isn't a friend, then it's a member template, in which
674  // case we just want to build the instantiation in the
675  // specialization.  If it is a friend, we want to build it in
676  // the appropriate context.
677  DeclContext *DC = Owner;
678  if (isFriend) {
679    if (QualifierLoc) {
680      CXXScopeSpec SS;
681      SS.Adopt(QualifierLoc);
682      DC = SemaRef.computeDeclContext(SS);
683      if (!DC) return 0;
684    } else {
685      DC = SemaRef.FindInstantiatedContext(Pattern->getLocation(),
686                                           Pattern->getDeclContext(),
687                                           TemplateArgs);
688    }
689
690    // Look for a previous declaration of the template in the owning
691    // context.
692    LookupResult R(SemaRef, Pattern->getDeclName(), Pattern->getLocation(),
693                   Sema::LookupOrdinaryName, Sema::ForRedeclaration);
694    SemaRef.LookupQualifiedName(R, DC);
695
696    if (R.isSingleResult()) {
697      PrevClassTemplate = R.getAsSingle<ClassTemplateDecl>();
698      if (PrevClassTemplate)
699        PrevDecl = PrevClassTemplate->getTemplatedDecl();
700    }
701
702    if (!PrevClassTemplate && QualifierLoc) {
703      SemaRef.Diag(Pattern->getLocation(), diag::err_not_tag_in_scope)
704        << D->getTemplatedDecl()->getTagKind() << Pattern->getDeclName() << DC
705        << QualifierLoc.getSourceRange();
706      return 0;
707    }
708
709    bool AdoptedPreviousTemplateParams = false;
710    if (PrevClassTemplate) {
711      bool Complain = true;
712
713      // HACK: libstdc++ 4.2.1 contains an ill-formed friend class
714      // template for struct std::tr1::__detail::_Map_base, where the
715      // template parameters of the friend declaration don't match the
716      // template parameters of the original declaration. In this one
717      // case, we don't complain about the ill-formed friend
718      // declaration.
719      if (isFriend && Pattern->getIdentifier() &&
720          Pattern->getIdentifier()->isStr("_Map_base") &&
721          DC->isNamespace() &&
722          cast<NamespaceDecl>(DC)->getIdentifier() &&
723          cast<NamespaceDecl>(DC)->getIdentifier()->isStr("__detail")) {
724        DeclContext *DCParent = DC->getParent();
725        if (DCParent->isNamespace() &&
726            cast<NamespaceDecl>(DCParent)->getIdentifier() &&
727            cast<NamespaceDecl>(DCParent)->getIdentifier()->isStr("tr1")) {
728          DeclContext *DCParent2 = DCParent->getParent();
729          if (DCParent2->isNamespace() &&
730              cast<NamespaceDecl>(DCParent2)->getIdentifier() &&
731              cast<NamespaceDecl>(DCParent2)->getIdentifier()->isStr("std") &&
732              DCParent2->getParent()->isTranslationUnit())
733            Complain = false;
734        }
735      }
736
737      TemplateParameterList *PrevParams
738        = PrevClassTemplate->getTemplateParameters();
739
740      // Make sure the parameter lists match.
741      if (!SemaRef.TemplateParameterListsAreEqual(InstParams, PrevParams,
742                                                  Complain,
743                                                  Sema::TPL_TemplateMatch)) {
744        if (Complain)
745          return 0;
746
747        AdoptedPreviousTemplateParams = true;
748        InstParams = PrevParams;
749      }
750
751      // Do some additional validation, then merge default arguments
752      // from the existing declarations.
753      if (!AdoptedPreviousTemplateParams &&
754          SemaRef.CheckTemplateParameterList(InstParams, PrevParams,
755                                             Sema::TPC_ClassTemplate))
756        return 0;
757    }
758  }
759
760  CXXRecordDecl *RecordInst
761    = CXXRecordDecl::Create(SemaRef.Context, Pattern->getTagKind(), DC,
762                            Pattern->getLocStart(), Pattern->getLocation(),
763                            Pattern->getIdentifier(), PrevDecl,
764                            /*DelayTypeCreation=*/true);
765
766  if (QualifierLoc)
767    RecordInst->setQualifierInfo(QualifierLoc);
768
769  ClassTemplateDecl *Inst
770    = ClassTemplateDecl::Create(SemaRef.Context, DC, D->getLocation(),
771                                D->getIdentifier(), InstParams, RecordInst,
772                                PrevClassTemplate);
773  RecordInst->setDescribedClassTemplate(Inst);
774
775  if (isFriend) {
776    if (PrevClassTemplate)
777      Inst->setAccess(PrevClassTemplate->getAccess());
778    else
779      Inst->setAccess(D->getAccess());
780
781    Inst->setObjectOfFriendDecl(PrevClassTemplate != 0);
782    // TODO: do we want to track the instantiation progeny of this
783    // friend target decl?
784  } else {
785    Inst->setAccess(D->getAccess());
786    if (!PrevClassTemplate)
787      Inst->setInstantiatedFromMemberTemplate(D);
788  }
789
790  // Trigger creation of the type for the instantiation.
791  SemaRef.Context.getInjectedClassNameType(RecordInst,
792                                    Inst->getInjectedClassNameSpecialization());
793
794  // Finish handling of friends.
795  if (isFriend) {
796    DC->makeDeclVisibleInContext(Inst, /*Recoverable*/ false);
797    return Inst;
798  }
799
800  Owner->addDecl(Inst);
801
802  if (!PrevClassTemplate) {
803    // Queue up any out-of-line partial specializations of this member
804    // class template; the client will force their instantiation once
805    // the enclosing class has been instantiated.
806    llvm::SmallVector<ClassTemplatePartialSpecializationDecl *, 4> PartialSpecs;
807    D->getPartialSpecializations(PartialSpecs);
808    for (unsigned I = 0, N = PartialSpecs.size(); I != N; ++I)
809      if (PartialSpecs[I]->isOutOfLine())
810        OutOfLinePartialSpecs.push_back(std::make_pair(Inst, PartialSpecs[I]));
811  }
812
813  return Inst;
814}
815
816Decl *
817TemplateDeclInstantiator::VisitClassTemplatePartialSpecializationDecl(
818                                   ClassTemplatePartialSpecializationDecl *D) {
819  ClassTemplateDecl *ClassTemplate = D->getSpecializedTemplate();
820
821  // Lookup the already-instantiated declaration in the instantiation
822  // of the class template and return that.
823  DeclContext::lookup_result Found
824    = Owner->lookup(ClassTemplate->getDeclName());
825  if (Found.first == Found.second)
826    return 0;
827
828  ClassTemplateDecl *InstClassTemplate
829    = dyn_cast<ClassTemplateDecl>(*Found.first);
830  if (!InstClassTemplate)
831    return 0;
832
833  if (ClassTemplatePartialSpecializationDecl *Result
834        = InstClassTemplate->findPartialSpecInstantiatedFromMember(D))
835    return Result;
836
837  return InstantiateClassTemplatePartialSpecialization(InstClassTemplate, D);
838}
839
840Decl *
841TemplateDeclInstantiator::VisitFunctionTemplateDecl(FunctionTemplateDecl *D) {
842  // Create a local instantiation scope for this function template, which
843  // will contain the instantiations of the template parameters and then get
844  // merged with the local instantiation scope for the function template
845  // itself.
846  LocalInstantiationScope Scope(SemaRef);
847
848  TemplateParameterList *TempParams = D->getTemplateParameters();
849  TemplateParameterList *InstParams = SubstTemplateParams(TempParams);
850  if (!InstParams)
851    return NULL;
852
853  FunctionDecl *Instantiated = 0;
854  if (CXXMethodDecl *DMethod = dyn_cast<CXXMethodDecl>(D->getTemplatedDecl()))
855    Instantiated = cast_or_null<FunctionDecl>(VisitCXXMethodDecl(DMethod,
856                                                                 InstParams));
857  else
858    Instantiated = cast_or_null<FunctionDecl>(VisitFunctionDecl(
859                                                          D->getTemplatedDecl(),
860                                                                InstParams));
861
862  if (!Instantiated)
863    return 0;
864
865  Instantiated->setAccess(D->getAccess());
866
867  // Link the instantiated function template declaration to the function
868  // template from which it was instantiated.
869  FunctionTemplateDecl *InstTemplate
870    = Instantiated->getDescribedFunctionTemplate();
871  InstTemplate->setAccess(D->getAccess());
872  assert(InstTemplate &&
873         "VisitFunctionDecl/CXXMethodDecl didn't create a template!");
874
875  bool isFriend = (InstTemplate->getFriendObjectKind() != Decl::FOK_None);
876
877  // Link the instantiation back to the pattern *unless* this is a
878  // non-definition friend declaration.
879  if (!InstTemplate->getInstantiatedFromMemberTemplate() &&
880      !(isFriend && !D->getTemplatedDecl()->isThisDeclarationADefinition()))
881    InstTemplate->setInstantiatedFromMemberTemplate(D);
882
883  // Make declarations visible in the appropriate context.
884  if (!isFriend)
885    Owner->addDecl(InstTemplate);
886
887  return InstTemplate;
888}
889
890Decl *TemplateDeclInstantiator::VisitCXXRecordDecl(CXXRecordDecl *D) {
891  CXXRecordDecl *PrevDecl = 0;
892  if (D->isInjectedClassName())
893    PrevDecl = cast<CXXRecordDecl>(Owner);
894  else if (D->getPreviousDeclaration()) {
895    NamedDecl *Prev = SemaRef.FindInstantiatedDecl(D->getLocation(),
896                                                   D->getPreviousDeclaration(),
897                                                   TemplateArgs);
898    if (!Prev) return 0;
899    PrevDecl = cast<CXXRecordDecl>(Prev);
900  }
901
902  CXXRecordDecl *Record
903    = CXXRecordDecl::Create(SemaRef.Context, D->getTagKind(), Owner,
904                            D->getLocStart(), D->getLocation(),
905                            D->getIdentifier(), PrevDecl);
906
907  // Substitute the nested name specifier, if any.
908  if (SubstQualifier(D, Record))
909    return 0;
910
911  Record->setImplicit(D->isImplicit());
912  // FIXME: Check against AS_none is an ugly hack to work around the issue that
913  // the tag decls introduced by friend class declarations don't have an access
914  // specifier. Remove once this area of the code gets sorted out.
915  if (D->getAccess() != AS_none)
916    Record->setAccess(D->getAccess());
917  if (!D->isInjectedClassName())
918    Record->setInstantiationOfMemberClass(D, TSK_ImplicitInstantiation);
919
920  // If the original function was part of a friend declaration,
921  // inherit its namespace state.
922  if (Decl::FriendObjectKind FOK = D->getFriendObjectKind())
923    Record->setObjectOfFriendDecl(FOK == Decl::FOK_Declared);
924
925  // Make sure that anonymous structs and unions are recorded.
926  if (D->isAnonymousStructOrUnion()) {
927    Record->setAnonymousStructOrUnion(true);
928    if (Record->getDeclContext()->getRedeclContext()->isFunctionOrMethod())
929      SemaRef.CurrentInstantiationScope->InstantiatedLocal(D, Record);
930  }
931
932  Owner->addDecl(Record);
933  return Record;
934}
935
936/// Normal class members are of more specific types and therefore
937/// don't make it here.  This function serves two purposes:
938///   1) instantiating function templates
939///   2) substituting friend declarations
940/// FIXME: preserve function definitions in case #2
941Decl *TemplateDeclInstantiator::VisitFunctionDecl(FunctionDecl *D,
942                                       TemplateParameterList *TemplateParams) {
943  // Check whether there is already a function template specialization for
944  // this declaration.
945  FunctionTemplateDecl *FunctionTemplate = D->getDescribedFunctionTemplate();
946  void *InsertPos = 0;
947  if (FunctionTemplate && !TemplateParams) {
948    std::pair<const TemplateArgument *, unsigned> Innermost
949      = TemplateArgs.getInnermost();
950
951    FunctionDecl *SpecFunc
952      = FunctionTemplate->findSpecialization(Innermost.first, Innermost.second,
953                                             InsertPos);
954
955    // If we already have a function template specialization, return it.
956    if (SpecFunc)
957      return SpecFunc;
958  }
959
960  bool isFriend;
961  if (FunctionTemplate)
962    isFriend = (FunctionTemplate->getFriendObjectKind() != Decl::FOK_None);
963  else
964    isFriend = (D->getFriendObjectKind() != Decl::FOK_None);
965
966  bool MergeWithParentScope = (TemplateParams != 0) ||
967    Owner->isFunctionOrMethod() ||
968    !(isa<Decl>(Owner) &&
969      cast<Decl>(Owner)->isDefinedOutsideFunctionOrMethod());
970  LocalInstantiationScope Scope(SemaRef, MergeWithParentScope);
971
972  llvm::SmallVector<ParmVarDecl *, 4> Params;
973  TypeSourceInfo *TInfo = D->getTypeSourceInfo();
974  TInfo = SubstFunctionType(D, Params);
975  if (!TInfo)
976    return 0;
977  QualType T = TInfo->getType();
978
979  NestedNameSpecifierLoc QualifierLoc = D->getQualifierLoc();
980  if (QualifierLoc) {
981    QualifierLoc = SemaRef.SubstNestedNameSpecifierLoc(QualifierLoc,
982                                                       TemplateArgs);
983    if (!QualifierLoc)
984      return 0;
985  }
986
987  // If we're instantiating a local function declaration, put the result
988  // in the owner;  otherwise we need to find the instantiated context.
989  DeclContext *DC;
990  if (D->getDeclContext()->isFunctionOrMethod())
991    DC = Owner;
992  else if (isFriend && QualifierLoc) {
993    CXXScopeSpec SS;
994    SS.Adopt(QualifierLoc);
995    DC = SemaRef.computeDeclContext(SS);
996    if (!DC) return 0;
997  } else {
998    DC = SemaRef.FindInstantiatedContext(D->getLocation(), D->getDeclContext(),
999                                         TemplateArgs);
1000  }
1001
1002  FunctionDecl *Function =
1003      FunctionDecl::Create(SemaRef.Context, DC, D->getInnerLocStart(),
1004                           D->getLocation(), D->getDeclName(), T, TInfo,
1005                           D->getStorageClass(), D->getStorageClassAsWritten(),
1006                           D->isInlineSpecified(), D->hasWrittenPrototype());
1007
1008  if (QualifierLoc)
1009    Function->setQualifierInfo(QualifierLoc);
1010
1011  DeclContext *LexicalDC = Owner;
1012  if (!isFriend && D->isOutOfLine()) {
1013    assert(D->getDeclContext()->isFileContext());
1014    LexicalDC = D->getDeclContext();
1015  }
1016
1017  Function->setLexicalDeclContext(LexicalDC);
1018
1019  // Attach the parameters
1020  for (unsigned P = 0; P < Params.size(); ++P)
1021    if (Params[P])
1022      Params[P]->setOwningFunction(Function);
1023  Function->setParams(Params.data(), Params.size());
1024
1025  SourceLocation InstantiateAtPOI;
1026  if (TemplateParams) {
1027    // Our resulting instantiation is actually a function template, since we
1028    // are substituting only the outer template parameters. For example, given
1029    //
1030    //   template<typename T>
1031    //   struct X {
1032    //     template<typename U> friend void f(T, U);
1033    //   };
1034    //
1035    //   X<int> x;
1036    //
1037    // We are instantiating the friend function template "f" within X<int>,
1038    // which means substituting int for T, but leaving "f" as a friend function
1039    // template.
1040    // Build the function template itself.
1041    FunctionTemplate = FunctionTemplateDecl::Create(SemaRef.Context, DC,
1042                                                    Function->getLocation(),
1043                                                    Function->getDeclName(),
1044                                                    TemplateParams, Function);
1045    Function->setDescribedFunctionTemplate(FunctionTemplate);
1046
1047    FunctionTemplate->setLexicalDeclContext(LexicalDC);
1048
1049    if (isFriend && D->isThisDeclarationADefinition()) {
1050      // TODO: should we remember this connection regardless of whether
1051      // the friend declaration provided a body?
1052      FunctionTemplate->setInstantiatedFromMemberTemplate(
1053                                           D->getDescribedFunctionTemplate());
1054    }
1055  } else if (FunctionTemplate) {
1056    // Record this function template specialization.
1057    std::pair<const TemplateArgument *, unsigned> Innermost
1058      = TemplateArgs.getInnermost();
1059    Function->setFunctionTemplateSpecialization(FunctionTemplate,
1060                            TemplateArgumentList::CreateCopy(SemaRef.Context,
1061                                                             Innermost.first,
1062                                                             Innermost.second),
1063                                                InsertPos);
1064  } else if (isFriend && D->isThisDeclarationADefinition()) {
1065    // TODO: should we remember this connection regardless of whether
1066    // the friend declaration provided a body?
1067    Function->setInstantiationOfMemberFunction(D, TSK_ImplicitInstantiation);
1068  }
1069
1070  if (InitFunctionInstantiation(Function, D))
1071    Function->setInvalidDecl();
1072
1073  bool Redeclaration = false;
1074  bool isExplicitSpecialization = false;
1075
1076  LookupResult Previous(SemaRef, Function->getDeclName(), SourceLocation(),
1077                        Sema::LookupOrdinaryName, Sema::ForRedeclaration);
1078
1079  if (DependentFunctionTemplateSpecializationInfo *Info
1080        = D->getDependentSpecializationInfo()) {
1081    assert(isFriend && "non-friend has dependent specialization info?");
1082
1083    // This needs to be set now for future sanity.
1084    Function->setObjectOfFriendDecl(/*HasPrevious*/ true);
1085
1086    // Instantiate the explicit template arguments.
1087    TemplateArgumentListInfo ExplicitArgs(Info->getLAngleLoc(),
1088                                          Info->getRAngleLoc());
1089    if (SemaRef.Subst(Info->getTemplateArgs(), Info->getNumTemplateArgs(),
1090                      ExplicitArgs, TemplateArgs))
1091      return 0;
1092
1093    // Map the candidate templates to their instantiations.
1094    for (unsigned I = 0, E = Info->getNumTemplates(); I != E; ++I) {
1095      Decl *Temp = SemaRef.FindInstantiatedDecl(D->getLocation(),
1096                                                Info->getTemplate(I),
1097                                                TemplateArgs);
1098      if (!Temp) return 0;
1099
1100      Previous.addDecl(cast<FunctionTemplateDecl>(Temp));
1101    }
1102
1103    if (SemaRef.CheckFunctionTemplateSpecialization(Function,
1104                                                    &ExplicitArgs,
1105                                                    Previous))
1106      Function->setInvalidDecl();
1107
1108    isExplicitSpecialization = true;
1109
1110  } else if (TemplateParams || !FunctionTemplate) {
1111    // Look only into the namespace where the friend would be declared to
1112    // find a previous declaration. This is the innermost enclosing namespace,
1113    // as described in ActOnFriendFunctionDecl.
1114    SemaRef.LookupQualifiedName(Previous, DC);
1115
1116    // In C++, the previous declaration we find might be a tag type
1117    // (class or enum). In this case, the new declaration will hide the
1118    // tag type. Note that this does does not apply if we're declaring a
1119    // typedef (C++ [dcl.typedef]p4).
1120    if (Previous.isSingleTagDecl())
1121      Previous.clear();
1122  }
1123
1124  SemaRef.CheckFunctionDeclaration(/*Scope*/ 0, Function, Previous,
1125                                   isExplicitSpecialization, Redeclaration);
1126
1127  NamedDecl *PrincipalDecl = (TemplateParams
1128                              ? cast<NamedDecl>(FunctionTemplate)
1129                              : Function);
1130
1131  // If the original function was part of a friend declaration,
1132  // inherit its namespace state and add it to the owner.
1133  if (isFriend) {
1134    NamedDecl *PrevDecl;
1135    if (TemplateParams)
1136      PrevDecl = FunctionTemplate->getPreviousDeclaration();
1137    else
1138      PrevDecl = Function->getPreviousDeclaration();
1139
1140    PrincipalDecl->setObjectOfFriendDecl(PrevDecl != 0);
1141    DC->makeDeclVisibleInContext(PrincipalDecl, /*Recoverable=*/ false);
1142
1143    bool queuedInstantiation = false;
1144
1145    if (!SemaRef.getLangOptions().CPlusPlus0x &&
1146        D->isThisDeclarationADefinition()) {
1147      // Check for a function body.
1148      const FunctionDecl *Definition = 0;
1149      if (Function->hasBody(Definition) &&
1150          Definition->getTemplateSpecializationKind() == TSK_Undeclared) {
1151        SemaRef.Diag(Function->getLocation(), diag::err_redefinition)
1152          << Function->getDeclName();
1153        SemaRef.Diag(Definition->getLocation(), diag::note_previous_definition);
1154        Function->setInvalidDecl();
1155      }
1156      // Check for redefinitions due to other instantiations of this or
1157      // a similar friend function.
1158      else for (FunctionDecl::redecl_iterator R = Function->redecls_begin(),
1159                                           REnd = Function->redecls_end();
1160                R != REnd; ++R) {
1161        if (*R == Function)
1162          continue;
1163        switch (R->getFriendObjectKind()) {
1164        case Decl::FOK_None:
1165          if (!queuedInstantiation && R->isUsed(false)) {
1166            if (MemberSpecializationInfo *MSInfo
1167                = Function->getMemberSpecializationInfo()) {
1168              if (MSInfo->getPointOfInstantiation().isInvalid()) {
1169                SourceLocation Loc = R->getLocation(); // FIXME
1170                MSInfo->setPointOfInstantiation(Loc);
1171                SemaRef.PendingLocalImplicitInstantiations.push_back(
1172                                                 std::make_pair(Function, Loc));
1173                queuedInstantiation = true;
1174              }
1175            }
1176          }
1177          break;
1178        default:
1179          if (const FunctionDecl *RPattern
1180              = R->getTemplateInstantiationPattern())
1181            if (RPattern->hasBody(RPattern)) {
1182              SemaRef.Diag(Function->getLocation(), diag::err_redefinition)
1183                << Function->getDeclName();
1184              SemaRef.Diag(R->getLocation(), diag::note_previous_definition);
1185              Function->setInvalidDecl();
1186              break;
1187            }
1188        }
1189      }
1190    }
1191  }
1192
1193  if (Function->isOverloadedOperator() && !DC->isRecord() &&
1194      PrincipalDecl->isInIdentifierNamespace(Decl::IDNS_Ordinary))
1195    PrincipalDecl->setNonMemberOperator();
1196
1197  return Function;
1198}
1199
1200Decl *
1201TemplateDeclInstantiator::VisitCXXMethodDecl(CXXMethodDecl *D,
1202                                      TemplateParameterList *TemplateParams) {
1203  FunctionTemplateDecl *FunctionTemplate = D->getDescribedFunctionTemplate();
1204  void *InsertPos = 0;
1205  if (FunctionTemplate && !TemplateParams) {
1206    // We are creating a function template specialization from a function
1207    // template. Check whether there is already a function template
1208    // specialization for this particular set of template arguments.
1209    std::pair<const TemplateArgument *, unsigned> Innermost
1210      = TemplateArgs.getInnermost();
1211
1212    FunctionDecl *SpecFunc
1213      = FunctionTemplate->findSpecialization(Innermost.first, Innermost.second,
1214                                             InsertPos);
1215
1216    // If we already have a function template specialization, return it.
1217    if (SpecFunc)
1218      return SpecFunc;
1219  }
1220
1221  bool isFriend;
1222  if (FunctionTemplate)
1223    isFriend = (FunctionTemplate->getFriendObjectKind() != Decl::FOK_None);
1224  else
1225    isFriend = (D->getFriendObjectKind() != Decl::FOK_None);
1226
1227  bool MergeWithParentScope = (TemplateParams != 0) ||
1228    !(isa<Decl>(Owner) &&
1229      cast<Decl>(Owner)->isDefinedOutsideFunctionOrMethod());
1230  LocalInstantiationScope Scope(SemaRef, MergeWithParentScope);
1231
1232  // Instantiate enclosing template arguments for friends.
1233  llvm::SmallVector<TemplateParameterList *, 4> TempParamLists;
1234  unsigned NumTempParamLists = 0;
1235  if (isFriend && (NumTempParamLists = D->getNumTemplateParameterLists())) {
1236    TempParamLists.set_size(NumTempParamLists);
1237    for (unsigned I = 0; I != NumTempParamLists; ++I) {
1238      TemplateParameterList *TempParams = D->getTemplateParameterList(I);
1239      TemplateParameterList *InstParams = SubstTemplateParams(TempParams);
1240      if (!InstParams)
1241        return NULL;
1242      TempParamLists[I] = InstParams;
1243    }
1244  }
1245
1246  llvm::SmallVector<ParmVarDecl *, 4> Params;
1247  TypeSourceInfo *TInfo = D->getTypeSourceInfo();
1248  TInfo = SubstFunctionType(D, Params);
1249  if (!TInfo)
1250    return 0;
1251  QualType T = TInfo->getType();
1252
1253  // \brief If the type of this function, after ignoring parentheses,
1254  // is not *directly* a function type, then we're instantiating a function
1255  // that was declared via a typedef, e.g.,
1256  //
1257  //   typedef int functype(int, int);
1258  //   functype func;
1259  //
1260  // In this case, we'll just go instantiate the ParmVarDecls that we
1261  // synthesized in the method declaration.
1262  if (!isa<FunctionProtoType>(T.IgnoreParens())) {
1263    assert(!Params.size() && "Instantiating type could not yield parameters");
1264    llvm::SmallVector<QualType, 4> ParamTypes;
1265    if (SemaRef.SubstParmTypes(D->getLocation(), D->param_begin(),
1266                               D->getNumParams(), TemplateArgs, ParamTypes,
1267                               &Params))
1268      return 0;
1269  }
1270
1271  NestedNameSpecifierLoc QualifierLoc = D->getQualifierLoc();
1272  if (QualifierLoc) {
1273    QualifierLoc = SemaRef.SubstNestedNameSpecifierLoc(QualifierLoc,
1274                                                 TemplateArgs);
1275    if (!QualifierLoc)
1276      return 0;
1277  }
1278
1279  DeclContext *DC = Owner;
1280  if (isFriend) {
1281    if (QualifierLoc) {
1282      CXXScopeSpec SS;
1283      SS.Adopt(QualifierLoc);
1284      DC = SemaRef.computeDeclContext(SS);
1285
1286      if (DC && SemaRef.RequireCompleteDeclContext(SS, DC))
1287        return 0;
1288    } else {
1289      DC = SemaRef.FindInstantiatedContext(D->getLocation(),
1290                                           D->getDeclContext(),
1291                                           TemplateArgs);
1292    }
1293    if (!DC) return 0;
1294  }
1295
1296  // Build the instantiated method declaration.
1297  CXXRecordDecl *Record = cast<CXXRecordDecl>(DC);
1298  CXXMethodDecl *Method = 0;
1299
1300  SourceLocation StartLoc = D->getInnerLocStart();
1301  DeclarationNameInfo NameInfo
1302    = SemaRef.SubstDeclarationNameInfo(D->getNameInfo(), TemplateArgs);
1303  if (CXXConstructorDecl *Constructor = dyn_cast<CXXConstructorDecl>(D)) {
1304    Method = CXXConstructorDecl::Create(SemaRef.Context, Record,
1305                                        StartLoc, NameInfo, T, TInfo,
1306                                        Constructor->isExplicit(),
1307                                        Constructor->isInlineSpecified(),
1308                                        false);
1309  } else if (CXXDestructorDecl *Destructor = dyn_cast<CXXDestructorDecl>(D)) {
1310    Method = CXXDestructorDecl::Create(SemaRef.Context, Record,
1311                                       StartLoc, NameInfo, T, TInfo,
1312                                       Destructor->isInlineSpecified(),
1313                                       false);
1314  } else if (CXXConversionDecl *Conversion = dyn_cast<CXXConversionDecl>(D)) {
1315    Method = CXXConversionDecl::Create(SemaRef.Context, Record,
1316                                       StartLoc, NameInfo, T, TInfo,
1317                                       Conversion->isInlineSpecified(),
1318                                       Conversion->isExplicit(),
1319                                       Conversion->getLocEnd());
1320  } else {
1321    Method = CXXMethodDecl::Create(SemaRef.Context, Record,
1322                                   StartLoc, NameInfo, T, TInfo,
1323                                   D->isStatic(),
1324                                   D->getStorageClassAsWritten(),
1325                                   D->isInlineSpecified(),
1326                                   D->getLocEnd());
1327  }
1328
1329  if (QualifierLoc)
1330    Method->setQualifierInfo(QualifierLoc);
1331
1332  if (TemplateParams) {
1333    // Our resulting instantiation is actually a function template, since we
1334    // are substituting only the outer template parameters. For example, given
1335    //
1336    //   template<typename T>
1337    //   struct X {
1338    //     template<typename U> void f(T, U);
1339    //   };
1340    //
1341    //   X<int> x;
1342    //
1343    // We are instantiating the member template "f" within X<int>, which means
1344    // substituting int for T, but leaving "f" as a member function template.
1345    // Build the function template itself.
1346    FunctionTemplate = FunctionTemplateDecl::Create(SemaRef.Context, Record,
1347                                                    Method->getLocation(),
1348                                                    Method->getDeclName(),
1349                                                    TemplateParams, Method);
1350    if (isFriend) {
1351      FunctionTemplate->setLexicalDeclContext(Owner);
1352      FunctionTemplate->setObjectOfFriendDecl(true);
1353    } else if (D->isOutOfLine())
1354      FunctionTemplate->setLexicalDeclContext(D->getLexicalDeclContext());
1355    Method->setDescribedFunctionTemplate(FunctionTemplate);
1356  } else if (FunctionTemplate) {
1357    // Record this function template specialization.
1358    std::pair<const TemplateArgument *, unsigned> Innermost
1359      = TemplateArgs.getInnermost();
1360    Method->setFunctionTemplateSpecialization(FunctionTemplate,
1361                         TemplateArgumentList::CreateCopy(SemaRef.Context,
1362                                                          Innermost.first,
1363                                                          Innermost.second),
1364                                              InsertPos);
1365  } else if (!isFriend) {
1366    // Record that this is an instantiation of a member function.
1367    Method->setInstantiationOfMemberFunction(D, TSK_ImplicitInstantiation);
1368  }
1369
1370  // If we are instantiating a member function defined
1371  // out-of-line, the instantiation will have the same lexical
1372  // context (which will be a namespace scope) as the template.
1373  if (isFriend) {
1374    if (NumTempParamLists)
1375      Method->setTemplateParameterListsInfo(SemaRef.Context,
1376                                            NumTempParamLists,
1377                                            TempParamLists.data());
1378
1379    Method->setLexicalDeclContext(Owner);
1380    Method->setObjectOfFriendDecl(true);
1381  } else if (D->isOutOfLine())
1382    Method->setLexicalDeclContext(D->getLexicalDeclContext());
1383
1384  // Attach the parameters
1385  for (unsigned P = 0; P < Params.size(); ++P)
1386    Params[P]->setOwningFunction(Method);
1387  Method->setParams(Params.data(), Params.size());
1388
1389  if (InitMethodInstantiation(Method, D))
1390    Method->setInvalidDecl();
1391
1392  LookupResult Previous(SemaRef, NameInfo, Sema::LookupOrdinaryName,
1393                        Sema::ForRedeclaration);
1394
1395  if (!FunctionTemplate || TemplateParams || isFriend) {
1396    SemaRef.LookupQualifiedName(Previous, Record);
1397
1398    // In C++, the previous declaration we find might be a tag type
1399    // (class or enum). In this case, the new declaration will hide the
1400    // tag type. Note that this does does not apply if we're declaring a
1401    // typedef (C++ [dcl.typedef]p4).
1402    if (Previous.isSingleTagDecl())
1403      Previous.clear();
1404  }
1405
1406  bool Redeclaration = false;
1407  SemaRef.CheckFunctionDeclaration(0, Method, Previous, false, Redeclaration);
1408
1409  if (D->isPure())
1410    SemaRef.CheckPureMethod(Method, SourceRange());
1411
1412  Method->setAccess(D->getAccess());
1413
1414  SemaRef.CheckOverrideControl(Method);
1415
1416  if (FunctionTemplate) {
1417    // If there's a function template, let our caller handle it.
1418  } else if (Method->isInvalidDecl() && !Previous.empty()) {
1419    // Don't hide a (potentially) valid declaration with an invalid one.
1420  } else {
1421    NamedDecl *DeclToAdd = (TemplateParams
1422                            ? cast<NamedDecl>(FunctionTemplate)
1423                            : Method);
1424    if (isFriend)
1425      Record->makeDeclVisibleInContext(DeclToAdd);
1426    else
1427      Owner->addDecl(DeclToAdd);
1428  }
1429
1430  return Method;
1431}
1432
1433Decl *TemplateDeclInstantiator::VisitCXXConstructorDecl(CXXConstructorDecl *D) {
1434  return VisitCXXMethodDecl(D);
1435}
1436
1437Decl *TemplateDeclInstantiator::VisitCXXDestructorDecl(CXXDestructorDecl *D) {
1438  return VisitCXXMethodDecl(D);
1439}
1440
1441Decl *TemplateDeclInstantiator::VisitCXXConversionDecl(CXXConversionDecl *D) {
1442  return VisitCXXMethodDecl(D);
1443}
1444
1445ParmVarDecl *TemplateDeclInstantiator::VisitParmVarDecl(ParmVarDecl *D) {
1446  return SemaRef.SubstParmVarDecl(D, TemplateArgs, llvm::Optional<unsigned>());
1447}
1448
1449Decl *TemplateDeclInstantiator::VisitTemplateTypeParmDecl(
1450                                                    TemplateTypeParmDecl *D) {
1451  // TODO: don't always clone when decls are refcounted.
1452  const Type* T = D->getTypeForDecl();
1453  assert(T->isTemplateTypeParmType());
1454  const TemplateTypeParmType *TTPT = T->getAs<TemplateTypeParmType>();
1455
1456  TemplateTypeParmDecl *Inst =
1457    TemplateTypeParmDecl::Create(SemaRef.Context, Owner,
1458                                 D->getLocStart(), D->getLocation(),
1459                                 TTPT->getDepth() - TemplateArgs.getNumLevels(),
1460                                 TTPT->getIndex(), D->getIdentifier(),
1461                                 D->wasDeclaredWithTypename(),
1462                                 D->isParameterPack());
1463  Inst->setAccess(AS_public);
1464
1465  if (D->hasDefaultArgument())
1466    Inst->setDefaultArgument(D->getDefaultArgumentInfo(), false);
1467
1468  // Introduce this template parameter's instantiation into the instantiation
1469  // scope.
1470  SemaRef.CurrentInstantiationScope->InstantiatedLocal(D, Inst);
1471
1472  return Inst;
1473}
1474
1475Decl *TemplateDeclInstantiator::VisitNonTypeTemplateParmDecl(
1476                                                 NonTypeTemplateParmDecl *D) {
1477  // Substitute into the type of the non-type template parameter.
1478  TypeLoc TL = D->getTypeSourceInfo()->getTypeLoc();
1479  llvm::SmallVector<TypeSourceInfo *, 4> ExpandedParameterPackTypesAsWritten;
1480  llvm::SmallVector<QualType, 4> ExpandedParameterPackTypes;
1481  bool IsExpandedParameterPack = false;
1482  TypeSourceInfo *DI;
1483  QualType T;
1484  bool Invalid = false;
1485
1486  if (D->isExpandedParameterPack()) {
1487    // The non-type template parameter pack is an already-expanded pack
1488    // expansion of types. Substitute into each of the expanded types.
1489    ExpandedParameterPackTypes.reserve(D->getNumExpansionTypes());
1490    ExpandedParameterPackTypesAsWritten.reserve(D->getNumExpansionTypes());
1491    for (unsigned I = 0, N = D->getNumExpansionTypes(); I != N; ++I) {
1492      TypeSourceInfo *NewDI =SemaRef.SubstType(D->getExpansionTypeSourceInfo(I),
1493                                               TemplateArgs,
1494                                               D->getLocation(),
1495                                               D->getDeclName());
1496      if (!NewDI)
1497        return 0;
1498
1499      ExpandedParameterPackTypesAsWritten.push_back(NewDI);
1500      QualType NewT =SemaRef.CheckNonTypeTemplateParameterType(NewDI->getType(),
1501                                                              D->getLocation());
1502      if (NewT.isNull())
1503        return 0;
1504      ExpandedParameterPackTypes.push_back(NewT);
1505    }
1506
1507    IsExpandedParameterPack = true;
1508    DI = D->getTypeSourceInfo();
1509    T = DI->getType();
1510  } else if (isa<PackExpansionTypeLoc>(TL)) {
1511    // The non-type template parameter pack's type is a pack expansion of types.
1512    // Determine whether we need to expand this parameter pack into separate
1513    // types.
1514    PackExpansionTypeLoc Expansion = cast<PackExpansionTypeLoc>(TL);
1515    TypeLoc Pattern = Expansion.getPatternLoc();
1516    llvm::SmallVector<UnexpandedParameterPack, 2> Unexpanded;
1517    SemaRef.collectUnexpandedParameterPacks(Pattern, Unexpanded);
1518
1519    // Determine whether the set of unexpanded parameter packs can and should
1520    // be expanded.
1521    bool Expand = true;
1522    bool RetainExpansion = false;
1523    llvm::Optional<unsigned> OrigNumExpansions
1524      = Expansion.getTypePtr()->getNumExpansions();
1525    llvm::Optional<unsigned> NumExpansions = OrigNumExpansions;
1526    if (SemaRef.CheckParameterPacksForExpansion(Expansion.getEllipsisLoc(),
1527                                                Pattern.getSourceRange(),
1528                                                Unexpanded.data(),
1529                                                Unexpanded.size(),
1530                                                TemplateArgs,
1531                                                Expand, RetainExpansion,
1532                                                NumExpansions))
1533      return 0;
1534
1535    if (Expand) {
1536      for (unsigned I = 0; I != *NumExpansions; ++I) {
1537        Sema::ArgumentPackSubstitutionIndexRAII SubstIndex(SemaRef, I);
1538        TypeSourceInfo *NewDI = SemaRef.SubstType(Pattern, TemplateArgs,
1539                                                  D->getLocation(),
1540                                                  D->getDeclName());
1541        if (!NewDI)
1542          return 0;
1543
1544        ExpandedParameterPackTypesAsWritten.push_back(NewDI);
1545        QualType NewT = SemaRef.CheckNonTypeTemplateParameterType(
1546                                                              NewDI->getType(),
1547                                                              D->getLocation());
1548        if (NewT.isNull())
1549          return 0;
1550        ExpandedParameterPackTypes.push_back(NewT);
1551      }
1552
1553      // Note that we have an expanded parameter pack. The "type" of this
1554      // expanded parameter pack is the original expansion type, but callers
1555      // will end up using the expanded parameter pack types for type-checking.
1556      IsExpandedParameterPack = true;
1557      DI = D->getTypeSourceInfo();
1558      T = DI->getType();
1559    } else {
1560      // We cannot fully expand the pack expansion now, so substitute into the
1561      // pattern and create a new pack expansion type.
1562      Sema::ArgumentPackSubstitutionIndexRAII SubstIndex(SemaRef, -1);
1563      TypeSourceInfo *NewPattern = SemaRef.SubstType(Pattern, TemplateArgs,
1564                                                     D->getLocation(),
1565                                                     D->getDeclName());
1566      if (!NewPattern)
1567        return 0;
1568
1569      DI = SemaRef.CheckPackExpansion(NewPattern, Expansion.getEllipsisLoc(),
1570                                      NumExpansions);
1571      if (!DI)
1572        return 0;
1573
1574      T = DI->getType();
1575    }
1576  } else {
1577    // Simple case: substitution into a parameter that is not a parameter pack.
1578    DI = SemaRef.SubstType(D->getTypeSourceInfo(), TemplateArgs,
1579                           D->getLocation(), D->getDeclName());
1580    if (!DI)
1581      return 0;
1582
1583    // Check that this type is acceptable for a non-type template parameter.
1584    bool Invalid = false;
1585    T = SemaRef.CheckNonTypeTemplateParameterType(DI->getType(),
1586                                                  D->getLocation());
1587    if (T.isNull()) {
1588      T = SemaRef.Context.IntTy;
1589      Invalid = true;
1590    }
1591  }
1592
1593  NonTypeTemplateParmDecl *Param;
1594  if (IsExpandedParameterPack)
1595    Param = NonTypeTemplateParmDecl::Create(SemaRef.Context, Owner,
1596                                            D->getInnerLocStart(),
1597                                            D->getLocation(),
1598                                    D->getDepth() - TemplateArgs.getNumLevels(),
1599                                            D->getPosition(),
1600                                            D->getIdentifier(), T,
1601                                            DI,
1602                                            ExpandedParameterPackTypes.data(),
1603                                            ExpandedParameterPackTypes.size(),
1604                                    ExpandedParameterPackTypesAsWritten.data());
1605  else
1606    Param = NonTypeTemplateParmDecl::Create(SemaRef.Context, Owner,
1607                                            D->getInnerLocStart(),
1608                                            D->getLocation(),
1609                                    D->getDepth() - TemplateArgs.getNumLevels(),
1610                                            D->getPosition(),
1611                                            D->getIdentifier(), T,
1612                                            D->isParameterPack(), DI);
1613
1614  Param->setAccess(AS_public);
1615  if (Invalid)
1616    Param->setInvalidDecl();
1617
1618  Param->setDefaultArgument(D->getDefaultArgument(), false);
1619
1620  // Introduce this template parameter's instantiation into the instantiation
1621  // scope.
1622  SemaRef.CurrentInstantiationScope->InstantiatedLocal(D, Param);
1623  return Param;
1624}
1625
1626Decl *
1627TemplateDeclInstantiator::VisitTemplateTemplateParmDecl(
1628                                                  TemplateTemplateParmDecl *D) {
1629  // Instantiate the template parameter list of the template template parameter.
1630  TemplateParameterList *TempParams = D->getTemplateParameters();
1631  TemplateParameterList *InstParams;
1632  {
1633    // Perform the actual substitution of template parameters within a new,
1634    // local instantiation scope.
1635    LocalInstantiationScope Scope(SemaRef);
1636    InstParams = SubstTemplateParams(TempParams);
1637    if (!InstParams)
1638      return NULL;
1639  }
1640
1641  // Build the template template parameter.
1642  TemplateTemplateParmDecl *Param
1643    = TemplateTemplateParmDecl::Create(SemaRef.Context, Owner, D->getLocation(),
1644                                   D->getDepth() - TemplateArgs.getNumLevels(),
1645                                       D->getPosition(), D->isParameterPack(),
1646                                       D->getIdentifier(), InstParams);
1647  Param->setDefaultArgument(D->getDefaultArgument(), false);
1648  Param->setAccess(AS_public);
1649
1650  // Introduce this template parameter's instantiation into the instantiation
1651  // scope.
1652  SemaRef.CurrentInstantiationScope->InstantiatedLocal(D, Param);
1653
1654  return Param;
1655}
1656
1657Decl *TemplateDeclInstantiator::VisitUsingDirectiveDecl(UsingDirectiveDecl *D) {
1658  // Using directives are never dependent (and never contain any types or
1659  // expressions), so they require no explicit instantiation work.
1660
1661  UsingDirectiveDecl *Inst
1662    = UsingDirectiveDecl::Create(SemaRef.Context, Owner, D->getLocation(),
1663                                 D->getNamespaceKeyLocation(),
1664                                 D->getQualifierLoc(),
1665                                 D->getIdentLocation(),
1666                                 D->getNominatedNamespace(),
1667                                 D->getCommonAncestor());
1668  Owner->addDecl(Inst);
1669  return Inst;
1670}
1671
1672Decl *TemplateDeclInstantiator::VisitUsingDecl(UsingDecl *D) {
1673
1674  // The nested name specifier may be dependent, for example
1675  //     template <typename T> struct t {
1676  //       struct s1 { T f1(); };
1677  //       struct s2 : s1 { using s1::f1; };
1678  //     };
1679  //     template struct t<int>;
1680  // Here, in using s1::f1, s1 refers to t<T>::s1;
1681  // we need to substitute for t<int>::s1.
1682  NestedNameSpecifierLoc QualifierLoc
1683    = SemaRef.SubstNestedNameSpecifierLoc(D->getQualifierLoc(),
1684                                          TemplateArgs);
1685  if (!QualifierLoc)
1686    return 0;
1687
1688  // The name info is non-dependent, so no transformation
1689  // is required.
1690  DeclarationNameInfo NameInfo = D->getNameInfo();
1691
1692  // We only need to do redeclaration lookups if we're in a class
1693  // scope (in fact, it's not really even possible in non-class
1694  // scopes).
1695  bool CheckRedeclaration = Owner->isRecord();
1696
1697  LookupResult Prev(SemaRef, NameInfo, Sema::LookupUsingDeclName,
1698                    Sema::ForRedeclaration);
1699
1700  UsingDecl *NewUD = UsingDecl::Create(SemaRef.Context, Owner,
1701                                       D->getUsingLocation(),
1702                                       QualifierLoc,
1703                                       NameInfo,
1704                                       D->isTypeName());
1705
1706  CXXScopeSpec SS;
1707  SS.Adopt(QualifierLoc);
1708  if (CheckRedeclaration) {
1709    Prev.setHideTags(false);
1710    SemaRef.LookupQualifiedName(Prev, Owner);
1711
1712    // Check for invalid redeclarations.
1713    if (SemaRef.CheckUsingDeclRedeclaration(D->getUsingLocation(),
1714                                            D->isTypeName(), SS,
1715                                            D->getLocation(), Prev))
1716      NewUD->setInvalidDecl();
1717
1718  }
1719
1720  if (!NewUD->isInvalidDecl() &&
1721      SemaRef.CheckUsingDeclQualifier(D->getUsingLocation(), SS,
1722                                      D->getLocation()))
1723    NewUD->setInvalidDecl();
1724
1725  SemaRef.Context.setInstantiatedFromUsingDecl(NewUD, D);
1726  NewUD->setAccess(D->getAccess());
1727  Owner->addDecl(NewUD);
1728
1729  // Don't process the shadow decls for an invalid decl.
1730  if (NewUD->isInvalidDecl())
1731    return NewUD;
1732
1733  bool isFunctionScope = Owner->isFunctionOrMethod();
1734
1735  // Process the shadow decls.
1736  for (UsingDecl::shadow_iterator I = D->shadow_begin(), E = D->shadow_end();
1737         I != E; ++I) {
1738    UsingShadowDecl *Shadow = *I;
1739    NamedDecl *InstTarget =
1740      cast_or_null<NamedDecl>(SemaRef.FindInstantiatedDecl(
1741                                                          Shadow->getLocation(),
1742                                                        Shadow->getTargetDecl(),
1743                                                           TemplateArgs));
1744    if (!InstTarget)
1745      return 0;
1746
1747    if (CheckRedeclaration &&
1748        SemaRef.CheckUsingShadowDecl(NewUD, InstTarget, Prev))
1749      continue;
1750
1751    UsingShadowDecl *InstShadow
1752      = SemaRef.BuildUsingShadowDecl(/*Scope*/ 0, NewUD, InstTarget);
1753    SemaRef.Context.setInstantiatedFromUsingShadowDecl(InstShadow, Shadow);
1754
1755    if (isFunctionScope)
1756      SemaRef.CurrentInstantiationScope->InstantiatedLocal(Shadow, InstShadow);
1757  }
1758
1759  return NewUD;
1760}
1761
1762Decl *TemplateDeclInstantiator::VisitUsingShadowDecl(UsingShadowDecl *D) {
1763  // Ignore these;  we handle them in bulk when processing the UsingDecl.
1764  return 0;
1765}
1766
1767Decl * TemplateDeclInstantiator
1768    ::VisitUnresolvedUsingTypenameDecl(UnresolvedUsingTypenameDecl *D) {
1769  NestedNameSpecifierLoc QualifierLoc
1770    = SemaRef.SubstNestedNameSpecifierLoc(D->getQualifierLoc(),
1771                                          TemplateArgs);
1772  if (!QualifierLoc)
1773    return 0;
1774
1775  CXXScopeSpec SS;
1776  SS.Adopt(QualifierLoc);
1777
1778  // Since NameInfo refers to a typename, it cannot be a C++ special name.
1779  // Hence, no tranformation is required for it.
1780  DeclarationNameInfo NameInfo(D->getDeclName(), D->getLocation());
1781  NamedDecl *UD =
1782    SemaRef.BuildUsingDeclaration(/*Scope*/ 0, D->getAccess(),
1783                                  D->getUsingLoc(), SS, NameInfo, 0,
1784                                  /*instantiation*/ true,
1785                                  /*typename*/ true, D->getTypenameLoc());
1786  if (UD)
1787    SemaRef.Context.setInstantiatedFromUsingDecl(cast<UsingDecl>(UD), D);
1788
1789  return UD;
1790}
1791
1792Decl * TemplateDeclInstantiator
1793    ::VisitUnresolvedUsingValueDecl(UnresolvedUsingValueDecl *D) {
1794  NestedNameSpecifierLoc QualifierLoc
1795      = SemaRef.SubstNestedNameSpecifierLoc(D->getQualifierLoc(), TemplateArgs);
1796  if (!QualifierLoc)
1797    return 0;
1798
1799  CXXScopeSpec SS;
1800  SS.Adopt(QualifierLoc);
1801
1802  DeclarationNameInfo NameInfo
1803    = SemaRef.SubstDeclarationNameInfo(D->getNameInfo(), TemplateArgs);
1804
1805  NamedDecl *UD =
1806    SemaRef.BuildUsingDeclaration(/*Scope*/ 0, D->getAccess(),
1807                                  D->getUsingLoc(), SS, NameInfo, 0,
1808                                  /*instantiation*/ true,
1809                                  /*typename*/ false, SourceLocation());
1810  if (UD)
1811    SemaRef.Context.setInstantiatedFromUsingDecl(cast<UsingDecl>(UD), D);
1812
1813  return UD;
1814}
1815
1816Decl *Sema::SubstDecl(Decl *D, DeclContext *Owner,
1817                      const MultiLevelTemplateArgumentList &TemplateArgs) {
1818  TemplateDeclInstantiator Instantiator(*this, Owner, TemplateArgs);
1819  if (D->isInvalidDecl())
1820    return 0;
1821
1822  return Instantiator.Visit(D);
1823}
1824
1825/// \brief Instantiates a nested template parameter list in the current
1826/// instantiation context.
1827///
1828/// \param L The parameter list to instantiate
1829///
1830/// \returns NULL if there was an error
1831TemplateParameterList *
1832TemplateDeclInstantiator::SubstTemplateParams(TemplateParameterList *L) {
1833  // Get errors for all the parameters before bailing out.
1834  bool Invalid = false;
1835
1836  unsigned N = L->size();
1837  typedef llvm::SmallVector<NamedDecl *, 8> ParamVector;
1838  ParamVector Params;
1839  Params.reserve(N);
1840  for (TemplateParameterList::iterator PI = L->begin(), PE = L->end();
1841       PI != PE; ++PI) {
1842    NamedDecl *D = cast_or_null<NamedDecl>(Visit(*PI));
1843    Params.push_back(D);
1844    Invalid = Invalid || !D || D->isInvalidDecl();
1845  }
1846
1847  // Clean up if we had an error.
1848  if (Invalid)
1849    return NULL;
1850
1851  TemplateParameterList *InstL
1852    = TemplateParameterList::Create(SemaRef.Context, L->getTemplateLoc(),
1853                                    L->getLAngleLoc(), &Params.front(), N,
1854                                    L->getRAngleLoc());
1855  return InstL;
1856}
1857
1858/// \brief Instantiate the declaration of a class template partial
1859/// specialization.
1860///
1861/// \param ClassTemplate the (instantiated) class template that is partially
1862// specialized by the instantiation of \p PartialSpec.
1863///
1864/// \param PartialSpec the (uninstantiated) class template partial
1865/// specialization that we are instantiating.
1866///
1867/// \returns The instantiated partial specialization, if successful; otherwise,
1868/// NULL to indicate an error.
1869ClassTemplatePartialSpecializationDecl *
1870TemplateDeclInstantiator::InstantiateClassTemplatePartialSpecialization(
1871                                            ClassTemplateDecl *ClassTemplate,
1872                          ClassTemplatePartialSpecializationDecl *PartialSpec) {
1873  // Create a local instantiation scope for this class template partial
1874  // specialization, which will contain the instantiations of the template
1875  // parameters.
1876  LocalInstantiationScope Scope(SemaRef);
1877
1878  // Substitute into the template parameters of the class template partial
1879  // specialization.
1880  TemplateParameterList *TempParams = PartialSpec->getTemplateParameters();
1881  TemplateParameterList *InstParams = SubstTemplateParams(TempParams);
1882  if (!InstParams)
1883    return 0;
1884
1885  // Substitute into the template arguments of the class template partial
1886  // specialization.
1887  TemplateArgumentListInfo InstTemplateArgs; // no angle locations
1888  if (SemaRef.Subst(PartialSpec->getTemplateArgsAsWritten(),
1889                    PartialSpec->getNumTemplateArgsAsWritten(),
1890                    InstTemplateArgs, TemplateArgs))
1891    return 0;
1892
1893  // Check that the template argument list is well-formed for this
1894  // class template.
1895  llvm::SmallVector<TemplateArgument, 4> Converted;
1896  if (SemaRef.CheckTemplateArgumentList(ClassTemplate,
1897                                        PartialSpec->getLocation(),
1898                                        InstTemplateArgs,
1899                                        false,
1900                                        Converted))
1901    return 0;
1902
1903  // Figure out where to insert this class template partial specialization
1904  // in the member template's set of class template partial specializations.
1905  void *InsertPos = 0;
1906  ClassTemplateSpecializationDecl *PrevDecl
1907    = ClassTemplate->findPartialSpecialization(Converted.data(),
1908                                               Converted.size(), InsertPos);
1909
1910  // Build the canonical type that describes the converted template
1911  // arguments of the class template partial specialization.
1912  QualType CanonType
1913    = SemaRef.Context.getTemplateSpecializationType(TemplateName(ClassTemplate),
1914                                                    Converted.data(),
1915                                                    Converted.size());
1916
1917  // Build the fully-sugared type for this class template
1918  // specialization as the user wrote in the specialization
1919  // itself. This means that we'll pretty-print the type retrieved
1920  // from the specialization's declaration the way that the user
1921  // actually wrote the specialization, rather than formatting the
1922  // name based on the "canonical" representation used to store the
1923  // template arguments in the specialization.
1924  TypeSourceInfo *WrittenTy
1925    = SemaRef.Context.getTemplateSpecializationTypeInfo(
1926                                                    TemplateName(ClassTemplate),
1927                                                    PartialSpec->getLocation(),
1928                                                    InstTemplateArgs,
1929                                                    CanonType);
1930
1931  if (PrevDecl) {
1932    // We've already seen a partial specialization with the same template
1933    // parameters and template arguments. This can happen, for example, when
1934    // substituting the outer template arguments ends up causing two
1935    // class template partial specializations of a member class template
1936    // to have identical forms, e.g.,
1937    //
1938    //   template<typename T, typename U>
1939    //   struct Outer {
1940    //     template<typename X, typename Y> struct Inner;
1941    //     template<typename Y> struct Inner<T, Y>;
1942    //     template<typename Y> struct Inner<U, Y>;
1943    //   };
1944    //
1945    //   Outer<int, int> outer; // error: the partial specializations of Inner
1946    //                          // have the same signature.
1947    SemaRef.Diag(PartialSpec->getLocation(), diag::err_partial_spec_redeclared)
1948      << WrittenTy->getType();
1949    SemaRef.Diag(PrevDecl->getLocation(), diag::note_prev_partial_spec_here)
1950      << SemaRef.Context.getTypeDeclType(PrevDecl);
1951    return 0;
1952  }
1953
1954
1955  // Create the class template partial specialization declaration.
1956  ClassTemplatePartialSpecializationDecl *InstPartialSpec
1957    = ClassTemplatePartialSpecializationDecl::Create(SemaRef.Context,
1958                                                     PartialSpec->getTagKind(),
1959                                                     Owner,
1960                                                     PartialSpec->getLocStart(),
1961                                                     PartialSpec->getLocation(),
1962                                                     InstParams,
1963                                                     ClassTemplate,
1964                                                     Converted.data(),
1965                                                     Converted.size(),
1966                                                     InstTemplateArgs,
1967                                                     CanonType,
1968                                                     0,
1969                             ClassTemplate->getNextPartialSpecSequenceNumber());
1970  // Substitute the nested name specifier, if any.
1971  if (SubstQualifier(PartialSpec, InstPartialSpec))
1972    return 0;
1973
1974  InstPartialSpec->setInstantiatedFromMember(PartialSpec);
1975  InstPartialSpec->setTypeAsWritten(WrittenTy);
1976
1977  // Add this partial specialization to the set of class template partial
1978  // specializations.
1979  ClassTemplate->AddPartialSpecialization(InstPartialSpec, InsertPos);
1980  return InstPartialSpec;
1981}
1982
1983TypeSourceInfo*
1984TemplateDeclInstantiator::SubstFunctionType(FunctionDecl *D,
1985                              llvm::SmallVectorImpl<ParmVarDecl *> &Params) {
1986  TypeSourceInfo *OldTInfo = D->getTypeSourceInfo();
1987  assert(OldTInfo && "substituting function without type source info");
1988  assert(Params.empty() && "parameter vector is non-empty at start");
1989  TypeSourceInfo *NewTInfo
1990    = SemaRef.SubstFunctionDeclType(OldTInfo, TemplateArgs,
1991                                    D->getTypeSpecStartLoc(),
1992                                    D->getDeclName());
1993  if (!NewTInfo)
1994    return 0;
1995
1996  if (NewTInfo != OldTInfo) {
1997    // Get parameters from the new type info.
1998    TypeLoc OldTL = OldTInfo->getTypeLoc().IgnoreParens();
1999    if (FunctionProtoTypeLoc *OldProtoLoc
2000                                  = dyn_cast<FunctionProtoTypeLoc>(&OldTL)) {
2001      TypeLoc NewTL = NewTInfo->getTypeLoc().IgnoreParens();
2002      FunctionProtoTypeLoc *NewProtoLoc = cast<FunctionProtoTypeLoc>(&NewTL);
2003      assert(NewProtoLoc && "Missing prototype?");
2004      unsigned NewIdx = 0, NumNewParams = NewProtoLoc->getNumArgs();
2005      for (unsigned OldIdx = 0, NumOldParams = OldProtoLoc->getNumArgs();
2006           OldIdx != NumOldParams; ++OldIdx) {
2007        ParmVarDecl *OldParam = OldProtoLoc->getArg(OldIdx);
2008        if (!OldParam->isParameterPack() ||
2009            (NewIdx < NumNewParams &&
2010             NewProtoLoc->getArg(NewIdx)->isParameterPack())) {
2011          // Simple case: normal parameter, or a parameter pack that's
2012          // instantiated to a (still-dependent) parameter pack.
2013          ParmVarDecl *NewParam = NewProtoLoc->getArg(NewIdx++);
2014          Params.push_back(NewParam);
2015          SemaRef.CurrentInstantiationScope->InstantiatedLocal(OldParam,
2016                                                               NewParam);
2017          continue;
2018        }
2019
2020        // Parameter pack: make the instantiation an argument pack.
2021        SemaRef.CurrentInstantiationScope->MakeInstantiatedLocalArgPack(
2022                                                                      OldParam);
2023        unsigned NumArgumentsInExpansion
2024          = SemaRef.getNumArgumentsInExpansion(OldParam->getType(),
2025                                               TemplateArgs);
2026        while (NumArgumentsInExpansion--) {
2027          ParmVarDecl *NewParam = NewProtoLoc->getArg(NewIdx++);
2028          Params.push_back(NewParam);
2029          SemaRef.CurrentInstantiationScope->InstantiatedLocalPackArg(OldParam,
2030                                                                      NewParam);
2031        }
2032      }
2033    }
2034  } else {
2035    // The function type itself was not dependent and therefore no
2036    // substitution occurred. However, we still need to instantiate
2037    // the function parameters themselves.
2038    TypeLoc OldTL = OldTInfo->getTypeLoc().IgnoreParens();
2039    if (FunctionProtoTypeLoc *OldProtoLoc
2040                                    = dyn_cast<FunctionProtoTypeLoc>(&OldTL)) {
2041      for (unsigned i = 0, i_end = OldProtoLoc->getNumArgs(); i != i_end; ++i) {
2042        ParmVarDecl *Parm = VisitParmVarDecl(OldProtoLoc->getArg(i));
2043        if (!Parm)
2044          return 0;
2045        Params.push_back(Parm);
2046      }
2047    }
2048  }
2049  return NewTInfo;
2050}
2051
2052/// \brief Initializes the common fields of an instantiation function
2053/// declaration (New) from the corresponding fields of its template (Tmpl).
2054///
2055/// \returns true if there was an error
2056bool
2057TemplateDeclInstantiator::InitFunctionInstantiation(FunctionDecl *New,
2058                                                    FunctionDecl *Tmpl) {
2059  if (Tmpl->isDeleted())
2060    New->setDeleted();
2061
2062  // If we are performing substituting explicitly-specified template arguments
2063  // or deduced template arguments into a function template and we reach this
2064  // point, we are now past the point where SFINAE applies and have committed
2065  // to keeping the new function template specialization. We therefore
2066  // convert the active template instantiation for the function template
2067  // into a template instantiation for this specific function template
2068  // specialization, which is not a SFINAE context, so that we diagnose any
2069  // further errors in the declaration itself.
2070  typedef Sema::ActiveTemplateInstantiation ActiveInstType;
2071  ActiveInstType &ActiveInst = SemaRef.ActiveTemplateInstantiations.back();
2072  if (ActiveInst.Kind == ActiveInstType::ExplicitTemplateArgumentSubstitution ||
2073      ActiveInst.Kind == ActiveInstType::DeducedTemplateArgumentSubstitution) {
2074    if (FunctionTemplateDecl *FunTmpl
2075          = dyn_cast<FunctionTemplateDecl>((Decl *)ActiveInst.Entity)) {
2076      assert(FunTmpl->getTemplatedDecl() == Tmpl &&
2077             "Deduction from the wrong function template?");
2078      (void) FunTmpl;
2079      ActiveInst.Kind = ActiveInstType::TemplateInstantiation;
2080      ActiveInst.Entity = reinterpret_cast<uintptr_t>(New);
2081      --SemaRef.NonInstantiationEntries;
2082    }
2083  }
2084
2085  const FunctionProtoType *Proto = Tmpl->getType()->getAs<FunctionProtoType>();
2086  assert(Proto && "Function template without prototype?");
2087
2088  if (Proto->hasExceptionSpec() || Proto->getNoReturnAttr()) {
2089    // The function has an exception specification or a "noreturn"
2090    // attribute. Substitute into each of the exception types.
2091    llvm::SmallVector<QualType, 4> Exceptions;
2092    for (unsigned I = 0, N = Proto->getNumExceptions(); I != N; ++I) {
2093      // FIXME: Poor location information!
2094      if (const PackExpansionType *PackExpansion
2095            = Proto->getExceptionType(I)->getAs<PackExpansionType>()) {
2096        // We have a pack expansion. Instantiate it.
2097        llvm::SmallVector<UnexpandedParameterPack, 2> Unexpanded;
2098        SemaRef.collectUnexpandedParameterPacks(PackExpansion->getPattern(),
2099                                                Unexpanded);
2100        assert(!Unexpanded.empty() &&
2101               "Pack expansion without parameter packs?");
2102
2103        bool Expand = false;
2104        bool RetainExpansion = false;
2105        llvm::Optional<unsigned> NumExpansions
2106                                          = PackExpansion->getNumExpansions();
2107        if (SemaRef.CheckParameterPacksForExpansion(New->getLocation(),
2108                                                    SourceRange(),
2109                                                    Unexpanded.data(),
2110                                                    Unexpanded.size(),
2111                                                    TemplateArgs,
2112                                                    Expand,
2113                                                    RetainExpansion,
2114                                                    NumExpansions))
2115          break;
2116
2117        if (!Expand) {
2118          // We can't expand this pack expansion into separate arguments yet;
2119          // just substitute into the pattern and create a new pack expansion
2120          // type.
2121          Sema::ArgumentPackSubstitutionIndexRAII SubstIndex(SemaRef, -1);
2122          QualType T = SemaRef.SubstType(PackExpansion->getPattern(),
2123                                         TemplateArgs,
2124                                       New->getLocation(), New->getDeclName());
2125          if (T.isNull())
2126            break;
2127
2128          T = SemaRef.Context.getPackExpansionType(T, NumExpansions);
2129          Exceptions.push_back(T);
2130          continue;
2131        }
2132
2133        // Substitute into the pack expansion pattern for each template
2134        bool Invalid = false;
2135        for (unsigned ArgIdx = 0; ArgIdx != *NumExpansions; ++ArgIdx) {
2136          Sema::ArgumentPackSubstitutionIndexRAII SubstIndex(SemaRef, ArgIdx);
2137
2138          QualType T = SemaRef.SubstType(PackExpansion->getPattern(),
2139                                         TemplateArgs,
2140                                       New->getLocation(), New->getDeclName());
2141          if (T.isNull()) {
2142            Invalid = true;
2143            break;
2144          }
2145
2146          Exceptions.push_back(T);
2147        }
2148
2149        if (Invalid)
2150          break;
2151
2152        continue;
2153      }
2154
2155      QualType T
2156        = SemaRef.SubstType(Proto->getExceptionType(I), TemplateArgs,
2157                            New->getLocation(), New->getDeclName());
2158      if (T.isNull() ||
2159          SemaRef.CheckSpecifiedExceptionType(T, New->getLocation()))
2160        continue;
2161
2162      Exceptions.push_back(T);
2163    }
2164    Expr *NoexceptExpr = 0;
2165    if (Expr *OldNoexceptExpr = Proto->getNoexceptExpr()) {
2166      ExprResult E = SemaRef.SubstExpr(OldNoexceptExpr, TemplateArgs);
2167      if (E.isUsable())
2168        NoexceptExpr = E.take();
2169    }
2170
2171    // Rebuild the function type
2172
2173    FunctionProtoType::ExtProtoInfo EPI = Proto->getExtProtoInfo();
2174    EPI.ExceptionSpecType = Proto->getExceptionSpecType();
2175    EPI.NumExceptions = Exceptions.size();
2176    EPI.Exceptions = Exceptions.data();
2177    EPI.NoexceptExpr = NoexceptExpr;
2178    EPI.ExtInfo = Proto->getExtInfo();
2179
2180    const FunctionProtoType *NewProto
2181      = New->getType()->getAs<FunctionProtoType>();
2182    assert(NewProto && "Template instantiation without function prototype?");
2183    New->setType(SemaRef.Context.getFunctionType(NewProto->getResultType(),
2184                                                 NewProto->arg_type_begin(),
2185                                                 NewProto->getNumArgs(),
2186                                                 EPI));
2187  }
2188
2189  SemaRef.InstantiateAttrs(TemplateArgs, Tmpl, New);
2190
2191  return false;
2192}
2193
2194/// \brief Initializes common fields of an instantiated method
2195/// declaration (New) from the corresponding fields of its template
2196/// (Tmpl).
2197///
2198/// \returns true if there was an error
2199bool
2200TemplateDeclInstantiator::InitMethodInstantiation(CXXMethodDecl *New,
2201                                                  CXXMethodDecl *Tmpl) {
2202  if (InitFunctionInstantiation(New, Tmpl))
2203    return true;
2204
2205  New->setAccess(Tmpl->getAccess());
2206  if (Tmpl->isVirtualAsWritten())
2207    New->setVirtualAsWritten(true);
2208
2209  // FIXME: attributes
2210  // FIXME: New needs a pointer to Tmpl
2211  return false;
2212}
2213
2214/// \brief Instantiate the definition of the given function from its
2215/// template.
2216///
2217/// \param PointOfInstantiation the point at which the instantiation was
2218/// required. Note that this is not precisely a "point of instantiation"
2219/// for the function, but it's close.
2220///
2221/// \param Function the already-instantiated declaration of a
2222/// function template specialization or member function of a class template
2223/// specialization.
2224///
2225/// \param Recursive if true, recursively instantiates any functions that
2226/// are required by this instantiation.
2227///
2228/// \param DefinitionRequired if true, then we are performing an explicit
2229/// instantiation where the body of the function is required. Complain if
2230/// there is no such body.
2231void Sema::InstantiateFunctionDefinition(SourceLocation PointOfInstantiation,
2232                                         FunctionDecl *Function,
2233                                         bool Recursive,
2234                                         bool DefinitionRequired) {
2235  if (Function->isInvalidDecl() || Function->hasBody())
2236    return;
2237
2238  // Never instantiate an explicit specialization.
2239  if (Function->getTemplateSpecializationKind() == TSK_ExplicitSpecialization)
2240    return;
2241
2242  // Find the function body that we'll be substituting.
2243  const FunctionDecl *PatternDecl = Function->getTemplateInstantiationPattern();
2244  Stmt *Pattern = 0;
2245  if (PatternDecl)
2246    Pattern = PatternDecl->getBody(PatternDecl);
2247
2248  if (!Pattern) {
2249    if (DefinitionRequired) {
2250      if (Function->getPrimaryTemplate())
2251        Diag(PointOfInstantiation,
2252             diag::err_explicit_instantiation_undefined_func_template)
2253          << Function->getPrimaryTemplate();
2254      else
2255        Diag(PointOfInstantiation,
2256             diag::err_explicit_instantiation_undefined_member)
2257          << 1 << Function->getDeclName() << Function->getDeclContext();
2258
2259      if (PatternDecl)
2260        Diag(PatternDecl->getLocation(),
2261             diag::note_explicit_instantiation_here);
2262      Function->setInvalidDecl();
2263    } else if (Function->getTemplateSpecializationKind()
2264                 == TSK_ExplicitInstantiationDefinition) {
2265      PendingInstantiations.push_back(
2266        std::make_pair(Function, PointOfInstantiation));
2267    }
2268
2269    return;
2270  }
2271
2272  // C++0x [temp.explicit]p9:
2273  //   Except for inline functions, other explicit instantiation declarations
2274  //   have the effect of suppressing the implicit instantiation of the entity
2275  //   to which they refer.
2276  if (Function->getTemplateSpecializationKind()
2277        == TSK_ExplicitInstantiationDeclaration &&
2278      !PatternDecl->isInlined())
2279    return;
2280
2281  InstantiatingTemplate Inst(*this, PointOfInstantiation, Function);
2282  if (Inst)
2283    return;
2284
2285  // If we're performing recursive template instantiation, create our own
2286  // queue of pending implicit instantiations that we will instantiate later,
2287  // while we're still within our own instantiation context.
2288  llvm::SmallVector<VTableUse, 16> SavedVTableUses;
2289  std::deque<PendingImplicitInstantiation> SavedPendingInstantiations;
2290  if (Recursive) {
2291    VTableUses.swap(SavedVTableUses);
2292    PendingInstantiations.swap(SavedPendingInstantiations);
2293  }
2294
2295  EnterExpressionEvaluationContext EvalContext(*this,
2296                                               Sema::PotentiallyEvaluated);
2297  ActOnStartOfFunctionDef(0, Function);
2298
2299  // Introduce a new scope where local variable instantiations will be
2300  // recorded, unless we're actually a member function within a local
2301  // class, in which case we need to merge our results with the parent
2302  // scope (of the enclosing function).
2303  bool MergeWithParentScope = false;
2304  if (CXXRecordDecl *Rec = dyn_cast<CXXRecordDecl>(Function->getDeclContext()))
2305    MergeWithParentScope = Rec->isLocalClass();
2306
2307  LocalInstantiationScope Scope(*this, MergeWithParentScope);
2308
2309  // Introduce the instantiated function parameters into the local
2310  // instantiation scope, and set the parameter names to those used
2311  // in the template.
2312  unsigned FParamIdx = 0;
2313  for (unsigned I = 0, N = PatternDecl->getNumParams(); I != N; ++I) {
2314    const ParmVarDecl *PatternParam = PatternDecl->getParamDecl(I);
2315    if (!PatternParam->isParameterPack()) {
2316      // Simple case: not a parameter pack.
2317      assert(FParamIdx < Function->getNumParams());
2318      ParmVarDecl *FunctionParam = Function->getParamDecl(I);
2319      FunctionParam->setDeclName(PatternParam->getDeclName());
2320      Scope.InstantiatedLocal(PatternParam, FunctionParam);
2321      ++FParamIdx;
2322      continue;
2323    }
2324
2325    // Expand the parameter pack.
2326    Scope.MakeInstantiatedLocalArgPack(PatternParam);
2327    for (unsigned NumFParams = Function->getNumParams();
2328         FParamIdx < NumFParams;
2329         ++FParamIdx) {
2330      ParmVarDecl *FunctionParam = Function->getParamDecl(FParamIdx);
2331      FunctionParam->setDeclName(PatternParam->getDeclName());
2332      Scope.InstantiatedLocalPackArg(PatternParam, FunctionParam);
2333    }
2334  }
2335
2336  // Enter the scope of this instantiation. We don't use
2337  // PushDeclContext because we don't have a scope.
2338  Sema::ContextRAII savedContext(*this, Function);
2339
2340  MultiLevelTemplateArgumentList TemplateArgs =
2341    getTemplateInstantiationArgs(Function, 0, false, PatternDecl);
2342
2343  // If this is a constructor, instantiate the member initializers.
2344  if (const CXXConstructorDecl *Ctor =
2345        dyn_cast<CXXConstructorDecl>(PatternDecl)) {
2346    InstantiateMemInitializers(cast<CXXConstructorDecl>(Function), Ctor,
2347                               TemplateArgs);
2348  }
2349
2350  // Instantiate the function body.
2351  StmtResult Body = SubstStmt(Pattern, TemplateArgs);
2352
2353  if (Body.isInvalid())
2354    Function->setInvalidDecl();
2355
2356  ActOnFinishFunctionBody(Function, Body.get(),
2357                          /*IsInstantiation=*/true);
2358
2359  PerformDependentDiagnostics(PatternDecl, TemplateArgs);
2360
2361  savedContext.pop();
2362
2363  DeclGroupRef DG(Function);
2364  Consumer.HandleTopLevelDecl(DG);
2365
2366  // This class may have local implicit instantiations that need to be
2367  // instantiation within this scope.
2368  PerformPendingInstantiations(/*LocalOnly=*/true);
2369  Scope.Exit();
2370
2371  if (Recursive) {
2372    // Define any pending vtables.
2373    DefineUsedVTables();
2374
2375    // Instantiate any pending implicit instantiations found during the
2376    // instantiation of this template.
2377    PerformPendingInstantiations();
2378
2379    // Restore the set of pending vtables.
2380    VTableUses.swap(SavedVTableUses);
2381
2382    // Restore the set of pending implicit instantiations.
2383    PendingInstantiations.swap(SavedPendingInstantiations);
2384  }
2385}
2386
2387/// \brief Instantiate the definition of the given variable from its
2388/// template.
2389///
2390/// \param PointOfInstantiation the point at which the instantiation was
2391/// required. Note that this is not precisely a "point of instantiation"
2392/// for the function, but it's close.
2393///
2394/// \param Var the already-instantiated declaration of a static member
2395/// variable of a class template specialization.
2396///
2397/// \param Recursive if true, recursively instantiates any functions that
2398/// are required by this instantiation.
2399///
2400/// \param DefinitionRequired if true, then we are performing an explicit
2401/// instantiation where an out-of-line definition of the member variable
2402/// is required. Complain if there is no such definition.
2403void Sema::InstantiateStaticDataMemberDefinition(
2404                                          SourceLocation PointOfInstantiation,
2405                                                 VarDecl *Var,
2406                                                 bool Recursive,
2407                                                 bool DefinitionRequired) {
2408  if (Var->isInvalidDecl())
2409    return;
2410
2411  // Find the out-of-line definition of this static data member.
2412  VarDecl *Def = Var->getInstantiatedFromStaticDataMember();
2413  assert(Def && "This data member was not instantiated from a template?");
2414  assert(Def->isStaticDataMember() && "Not a static data member?");
2415  Def = Def->getOutOfLineDefinition();
2416
2417  if (!Def) {
2418    // We did not find an out-of-line definition of this static data member,
2419    // so we won't perform any instantiation. Rather, we rely on the user to
2420    // instantiate this definition (or provide a specialization for it) in
2421    // another translation unit.
2422    if (DefinitionRequired) {
2423      Def = Var->getInstantiatedFromStaticDataMember();
2424      Diag(PointOfInstantiation,
2425           diag::err_explicit_instantiation_undefined_member)
2426        << 2 << Var->getDeclName() << Var->getDeclContext();
2427      Diag(Def->getLocation(), diag::note_explicit_instantiation_here);
2428    } else if (Var->getTemplateSpecializationKind()
2429                 == TSK_ExplicitInstantiationDefinition) {
2430      PendingInstantiations.push_back(
2431        std::make_pair(Var, PointOfInstantiation));
2432    }
2433
2434    return;
2435  }
2436
2437  // Never instantiate an explicit specialization.
2438  if (Var->getTemplateSpecializationKind() == TSK_ExplicitSpecialization)
2439    return;
2440
2441  // C++0x [temp.explicit]p9:
2442  //   Except for inline functions, other explicit instantiation declarations
2443  //   have the effect of suppressing the implicit instantiation of the entity
2444  //   to which they refer.
2445  if (Var->getTemplateSpecializationKind()
2446        == TSK_ExplicitInstantiationDeclaration)
2447    return;
2448
2449  InstantiatingTemplate Inst(*this, PointOfInstantiation, Var);
2450  if (Inst)
2451    return;
2452
2453  // If we're performing recursive template instantiation, create our own
2454  // queue of pending implicit instantiations that we will instantiate later,
2455  // while we're still within our own instantiation context.
2456  std::deque<PendingImplicitInstantiation> SavedPendingInstantiations;
2457  if (Recursive)
2458    PendingInstantiations.swap(SavedPendingInstantiations);
2459
2460  // Enter the scope of this instantiation. We don't use
2461  // PushDeclContext because we don't have a scope.
2462  ContextRAII previousContext(*this, Var->getDeclContext());
2463
2464  VarDecl *OldVar = Var;
2465  Var = cast_or_null<VarDecl>(SubstDecl(Def, Var->getDeclContext(),
2466                                        getTemplateInstantiationArgs(Var)));
2467
2468  previousContext.pop();
2469
2470  if (Var) {
2471    MemberSpecializationInfo *MSInfo = OldVar->getMemberSpecializationInfo();
2472    assert(MSInfo && "Missing member specialization information?");
2473    Var->setTemplateSpecializationKind(MSInfo->getTemplateSpecializationKind(),
2474                                       MSInfo->getPointOfInstantiation());
2475    DeclGroupRef DG(Var);
2476    Consumer.HandleTopLevelDecl(DG);
2477  }
2478
2479  if (Recursive) {
2480    // Instantiate any pending implicit instantiations found during the
2481    // instantiation of this template.
2482    PerformPendingInstantiations();
2483
2484    // Restore the set of pending implicit instantiations.
2485    PendingInstantiations.swap(SavedPendingInstantiations);
2486  }
2487}
2488
2489void
2490Sema::InstantiateMemInitializers(CXXConstructorDecl *New,
2491                                 const CXXConstructorDecl *Tmpl,
2492                           const MultiLevelTemplateArgumentList &TemplateArgs) {
2493
2494  llvm::SmallVector<MemInitTy*, 4> NewInits;
2495  bool AnyErrors = false;
2496
2497  // Instantiate all the initializers.
2498  for (CXXConstructorDecl::init_const_iterator Inits = Tmpl->init_begin(),
2499                                            InitsEnd = Tmpl->init_end();
2500       Inits != InitsEnd; ++Inits) {
2501    CXXCtorInitializer *Init = *Inits;
2502
2503    // Only instantiate written initializers, let Sema re-construct implicit
2504    // ones.
2505    if (!Init->isWritten())
2506      continue;
2507
2508    SourceLocation LParenLoc, RParenLoc;
2509    ASTOwningVector<Expr*> NewArgs(*this);
2510
2511    SourceLocation EllipsisLoc;
2512
2513    if (Init->isPackExpansion()) {
2514      // This is a pack expansion. We should expand it now.
2515      TypeLoc BaseTL = Init->getBaseClassInfo()->getTypeLoc();
2516      llvm::SmallVector<UnexpandedParameterPack, 2> Unexpanded;
2517      collectUnexpandedParameterPacks(BaseTL, Unexpanded);
2518      bool ShouldExpand = false;
2519      bool RetainExpansion = false;
2520      llvm::Optional<unsigned> NumExpansions;
2521      if (CheckParameterPacksForExpansion(Init->getEllipsisLoc(),
2522                                          BaseTL.getSourceRange(),
2523                                          Unexpanded.data(),
2524                                          Unexpanded.size(),
2525                                          TemplateArgs, ShouldExpand,
2526                                          RetainExpansion,
2527                                          NumExpansions)) {
2528        AnyErrors = true;
2529        New->setInvalidDecl();
2530        continue;
2531      }
2532      assert(ShouldExpand && "Partial instantiation of base initializer?");
2533
2534      // Loop over all of the arguments in the argument pack(s),
2535      for (unsigned I = 0; I != *NumExpansions; ++I) {
2536        Sema::ArgumentPackSubstitutionIndexRAII SubstIndex(*this, I);
2537
2538        // Instantiate the initializer.
2539        if (InstantiateInitializer(*this, Init->getInit(), TemplateArgs,
2540                                   LParenLoc, NewArgs, RParenLoc)) {
2541          AnyErrors = true;
2542          break;
2543        }
2544
2545        // Instantiate the base type.
2546        TypeSourceInfo *BaseTInfo = SubstType(Init->getBaseClassInfo(),
2547                                              TemplateArgs,
2548                                              Init->getSourceLocation(),
2549                                              New->getDeclName());
2550        if (!BaseTInfo) {
2551          AnyErrors = true;
2552          break;
2553        }
2554
2555        // Build the initializer.
2556        MemInitResult NewInit = BuildBaseInitializer(BaseTInfo->getType(),
2557                                                     BaseTInfo,
2558                                                     (Expr **)NewArgs.data(),
2559                                                     NewArgs.size(),
2560                                                     Init->getLParenLoc(),
2561                                                     Init->getRParenLoc(),
2562                                                     New->getParent(),
2563                                                     SourceLocation());
2564        if (NewInit.isInvalid()) {
2565          AnyErrors = true;
2566          break;
2567        }
2568
2569        NewInits.push_back(NewInit.get());
2570        NewArgs.clear();
2571      }
2572
2573      continue;
2574    }
2575
2576    // Instantiate the initializer.
2577    if (InstantiateInitializer(*this, Init->getInit(), TemplateArgs,
2578                               LParenLoc, NewArgs, RParenLoc)) {
2579      AnyErrors = true;
2580      continue;
2581    }
2582
2583    MemInitResult NewInit;
2584    if (Init->isBaseInitializer()) {
2585      TypeSourceInfo *BaseTInfo = SubstType(Init->getBaseClassInfo(),
2586                                            TemplateArgs,
2587                                            Init->getSourceLocation(),
2588                                            New->getDeclName());
2589      if (!BaseTInfo) {
2590        AnyErrors = true;
2591        New->setInvalidDecl();
2592        continue;
2593      }
2594
2595      NewInit = BuildBaseInitializer(BaseTInfo->getType(), BaseTInfo,
2596                                     (Expr **)NewArgs.data(),
2597                                     NewArgs.size(),
2598                                     Init->getLParenLoc(),
2599                                     Init->getRParenLoc(),
2600                                     New->getParent(),
2601                                     EllipsisLoc);
2602    } else if (Init->isMemberInitializer()) {
2603      FieldDecl *Member = cast_or_null<FieldDecl>(FindInstantiatedDecl(
2604                                                     Init->getMemberLocation(),
2605                                                     Init->getMember(),
2606                                                     TemplateArgs));
2607      if (!Member) {
2608        AnyErrors = true;
2609        New->setInvalidDecl();
2610        continue;
2611      }
2612
2613      NewInit = BuildMemberInitializer(Member, (Expr **)NewArgs.data(),
2614                                       NewArgs.size(),
2615                                       Init->getSourceLocation(),
2616                                       Init->getLParenLoc(),
2617                                       Init->getRParenLoc());
2618    } else if (Init->isIndirectMemberInitializer()) {
2619      IndirectFieldDecl *IndirectMember =
2620         cast_or_null<IndirectFieldDecl>(FindInstantiatedDecl(
2621                                 Init->getMemberLocation(),
2622                                 Init->getIndirectMember(), TemplateArgs));
2623
2624      if (!IndirectMember) {
2625        AnyErrors = true;
2626        New->setInvalidDecl();
2627        continue;
2628      }
2629
2630      NewInit = BuildMemberInitializer(IndirectMember, (Expr **)NewArgs.data(),
2631                                       NewArgs.size(),
2632                                       Init->getSourceLocation(),
2633                                       Init->getLParenLoc(),
2634                                       Init->getRParenLoc());
2635    }
2636
2637    if (NewInit.isInvalid()) {
2638      AnyErrors = true;
2639      New->setInvalidDecl();
2640    } else {
2641      // FIXME: It would be nice if ASTOwningVector had a release function.
2642      NewArgs.take();
2643
2644      NewInits.push_back((MemInitTy *)NewInit.get());
2645    }
2646  }
2647
2648  // Assign all the initializers to the new constructor.
2649  ActOnMemInitializers(New,
2650                       /*FIXME: ColonLoc */
2651                       SourceLocation(),
2652                       NewInits.data(), NewInits.size(),
2653                       AnyErrors);
2654}
2655
2656// TODO: this could be templated if the various decl types used the
2657// same method name.
2658static bool isInstantiationOf(ClassTemplateDecl *Pattern,
2659                              ClassTemplateDecl *Instance) {
2660  Pattern = Pattern->getCanonicalDecl();
2661
2662  do {
2663    Instance = Instance->getCanonicalDecl();
2664    if (Pattern == Instance) return true;
2665    Instance = Instance->getInstantiatedFromMemberTemplate();
2666  } while (Instance);
2667
2668  return false;
2669}
2670
2671static bool isInstantiationOf(FunctionTemplateDecl *Pattern,
2672                              FunctionTemplateDecl *Instance) {
2673  Pattern = Pattern->getCanonicalDecl();
2674
2675  do {
2676    Instance = Instance->getCanonicalDecl();
2677    if (Pattern == Instance) return true;
2678    Instance = Instance->getInstantiatedFromMemberTemplate();
2679  } while (Instance);
2680
2681  return false;
2682}
2683
2684static bool
2685isInstantiationOf(ClassTemplatePartialSpecializationDecl *Pattern,
2686                  ClassTemplatePartialSpecializationDecl *Instance) {
2687  Pattern
2688    = cast<ClassTemplatePartialSpecializationDecl>(Pattern->getCanonicalDecl());
2689  do {
2690    Instance = cast<ClassTemplatePartialSpecializationDecl>(
2691                                                Instance->getCanonicalDecl());
2692    if (Pattern == Instance)
2693      return true;
2694    Instance = Instance->getInstantiatedFromMember();
2695  } while (Instance);
2696
2697  return false;
2698}
2699
2700static bool isInstantiationOf(CXXRecordDecl *Pattern,
2701                              CXXRecordDecl *Instance) {
2702  Pattern = Pattern->getCanonicalDecl();
2703
2704  do {
2705    Instance = Instance->getCanonicalDecl();
2706    if (Pattern == Instance) return true;
2707    Instance = Instance->getInstantiatedFromMemberClass();
2708  } while (Instance);
2709
2710  return false;
2711}
2712
2713static bool isInstantiationOf(FunctionDecl *Pattern,
2714                              FunctionDecl *Instance) {
2715  Pattern = Pattern->getCanonicalDecl();
2716
2717  do {
2718    Instance = Instance->getCanonicalDecl();
2719    if (Pattern == Instance) return true;
2720    Instance = Instance->getInstantiatedFromMemberFunction();
2721  } while (Instance);
2722
2723  return false;
2724}
2725
2726static bool isInstantiationOf(EnumDecl *Pattern,
2727                              EnumDecl *Instance) {
2728  Pattern = Pattern->getCanonicalDecl();
2729
2730  do {
2731    Instance = Instance->getCanonicalDecl();
2732    if (Pattern == Instance) return true;
2733    Instance = Instance->getInstantiatedFromMemberEnum();
2734  } while (Instance);
2735
2736  return false;
2737}
2738
2739static bool isInstantiationOf(UsingShadowDecl *Pattern,
2740                              UsingShadowDecl *Instance,
2741                              ASTContext &C) {
2742  return C.getInstantiatedFromUsingShadowDecl(Instance) == Pattern;
2743}
2744
2745static bool isInstantiationOf(UsingDecl *Pattern,
2746                              UsingDecl *Instance,
2747                              ASTContext &C) {
2748  return C.getInstantiatedFromUsingDecl(Instance) == Pattern;
2749}
2750
2751static bool isInstantiationOf(UnresolvedUsingValueDecl *Pattern,
2752                              UsingDecl *Instance,
2753                              ASTContext &C) {
2754  return C.getInstantiatedFromUsingDecl(Instance) == Pattern;
2755}
2756
2757static bool isInstantiationOf(UnresolvedUsingTypenameDecl *Pattern,
2758                              UsingDecl *Instance,
2759                              ASTContext &C) {
2760  return C.getInstantiatedFromUsingDecl(Instance) == Pattern;
2761}
2762
2763static bool isInstantiationOfStaticDataMember(VarDecl *Pattern,
2764                                              VarDecl *Instance) {
2765  assert(Instance->isStaticDataMember());
2766
2767  Pattern = Pattern->getCanonicalDecl();
2768
2769  do {
2770    Instance = Instance->getCanonicalDecl();
2771    if (Pattern == Instance) return true;
2772    Instance = Instance->getInstantiatedFromStaticDataMember();
2773  } while (Instance);
2774
2775  return false;
2776}
2777
2778// Other is the prospective instantiation
2779// D is the prospective pattern
2780static bool isInstantiationOf(ASTContext &Ctx, NamedDecl *D, Decl *Other) {
2781  if (D->getKind() != Other->getKind()) {
2782    if (UnresolvedUsingTypenameDecl *UUD
2783          = dyn_cast<UnresolvedUsingTypenameDecl>(D)) {
2784      if (UsingDecl *UD = dyn_cast<UsingDecl>(Other)) {
2785        return isInstantiationOf(UUD, UD, Ctx);
2786      }
2787    }
2788
2789    if (UnresolvedUsingValueDecl *UUD
2790          = dyn_cast<UnresolvedUsingValueDecl>(D)) {
2791      if (UsingDecl *UD = dyn_cast<UsingDecl>(Other)) {
2792        return isInstantiationOf(UUD, UD, Ctx);
2793      }
2794    }
2795
2796    return false;
2797  }
2798
2799  if (CXXRecordDecl *Record = dyn_cast<CXXRecordDecl>(Other))
2800    return isInstantiationOf(cast<CXXRecordDecl>(D), Record);
2801
2802  if (FunctionDecl *Function = dyn_cast<FunctionDecl>(Other))
2803    return isInstantiationOf(cast<FunctionDecl>(D), Function);
2804
2805  if (EnumDecl *Enum = dyn_cast<EnumDecl>(Other))
2806    return isInstantiationOf(cast<EnumDecl>(D), Enum);
2807
2808  if (VarDecl *Var = dyn_cast<VarDecl>(Other))
2809    if (Var->isStaticDataMember())
2810      return isInstantiationOfStaticDataMember(cast<VarDecl>(D), Var);
2811
2812  if (ClassTemplateDecl *Temp = dyn_cast<ClassTemplateDecl>(Other))
2813    return isInstantiationOf(cast<ClassTemplateDecl>(D), Temp);
2814
2815  if (FunctionTemplateDecl *Temp = dyn_cast<FunctionTemplateDecl>(Other))
2816    return isInstantiationOf(cast<FunctionTemplateDecl>(D), Temp);
2817
2818  if (ClassTemplatePartialSpecializationDecl *PartialSpec
2819        = dyn_cast<ClassTemplatePartialSpecializationDecl>(Other))
2820    return isInstantiationOf(cast<ClassTemplatePartialSpecializationDecl>(D),
2821                             PartialSpec);
2822
2823  if (FieldDecl *Field = dyn_cast<FieldDecl>(Other)) {
2824    if (!Field->getDeclName()) {
2825      // This is an unnamed field.
2826      return Ctx.getInstantiatedFromUnnamedFieldDecl(Field) ==
2827        cast<FieldDecl>(D);
2828    }
2829  }
2830
2831  if (UsingDecl *Using = dyn_cast<UsingDecl>(Other))
2832    return isInstantiationOf(cast<UsingDecl>(D), Using, Ctx);
2833
2834  if (UsingShadowDecl *Shadow = dyn_cast<UsingShadowDecl>(Other))
2835    return isInstantiationOf(cast<UsingShadowDecl>(D), Shadow, Ctx);
2836
2837  return D->getDeclName() && isa<NamedDecl>(Other) &&
2838    D->getDeclName() == cast<NamedDecl>(Other)->getDeclName();
2839}
2840
2841template<typename ForwardIterator>
2842static NamedDecl *findInstantiationOf(ASTContext &Ctx,
2843                                      NamedDecl *D,
2844                                      ForwardIterator first,
2845                                      ForwardIterator last) {
2846  for (; first != last; ++first)
2847    if (isInstantiationOf(Ctx, D, *first))
2848      return cast<NamedDecl>(*first);
2849
2850  return 0;
2851}
2852
2853/// \brief Finds the instantiation of the given declaration context
2854/// within the current instantiation.
2855///
2856/// \returns NULL if there was an error
2857DeclContext *Sema::FindInstantiatedContext(SourceLocation Loc, DeclContext* DC,
2858                          const MultiLevelTemplateArgumentList &TemplateArgs) {
2859  if (NamedDecl *D = dyn_cast<NamedDecl>(DC)) {
2860    Decl* ID = FindInstantiatedDecl(Loc, D, TemplateArgs);
2861    return cast_or_null<DeclContext>(ID);
2862  } else return DC;
2863}
2864
2865/// \brief Find the instantiation of the given declaration within the
2866/// current instantiation.
2867///
2868/// This routine is intended to be used when \p D is a declaration
2869/// referenced from within a template, that needs to mapped into the
2870/// corresponding declaration within an instantiation. For example,
2871/// given:
2872///
2873/// \code
2874/// template<typename T>
2875/// struct X {
2876///   enum Kind {
2877///     KnownValue = sizeof(T)
2878///   };
2879///
2880///   bool getKind() const { return KnownValue; }
2881/// };
2882///
2883/// template struct X<int>;
2884/// \endcode
2885///
2886/// In the instantiation of X<int>::getKind(), we need to map the
2887/// EnumConstantDecl for KnownValue (which refers to
2888/// X<T>::<Kind>::KnownValue) to its instantiation
2889/// (X<int>::<Kind>::KnownValue). InstantiateCurrentDeclRef() performs
2890/// this mapping from within the instantiation of X<int>.
2891NamedDecl *Sema::FindInstantiatedDecl(SourceLocation Loc, NamedDecl *D,
2892                          const MultiLevelTemplateArgumentList &TemplateArgs) {
2893  DeclContext *ParentDC = D->getDeclContext();
2894  if (isa<ParmVarDecl>(D) || isa<NonTypeTemplateParmDecl>(D) ||
2895      isa<TemplateTypeParmDecl>(D) || isa<TemplateTemplateParmDecl>(D) ||
2896      (ParentDC->isFunctionOrMethod() && ParentDC->isDependentContext())) {
2897    // D is a local of some kind. Look into the map of local
2898    // declarations to their instantiations.
2899    typedef LocalInstantiationScope::DeclArgumentPack DeclArgumentPack;
2900    llvm::PointerUnion<Decl *, DeclArgumentPack *> *Found
2901      = CurrentInstantiationScope->findInstantiationOf(D);
2902
2903    if (Found) {
2904      if (Decl *FD = Found->dyn_cast<Decl *>())
2905        return cast<NamedDecl>(FD);
2906
2907      unsigned PackIdx = ArgumentPackSubstitutionIndex;
2908      return cast<NamedDecl>((*Found->get<DeclArgumentPack *>())[PackIdx]);
2909    }
2910
2911    // If we didn't find the decl, then we must have a label decl that hasn't
2912    // been found yet.  Lazily instantiate it and return it now.
2913    assert(isa<LabelDecl>(D));
2914
2915    Decl *Inst = SubstDecl(D, CurContext, TemplateArgs);
2916    assert(Inst && "Failed to instantiate label??");
2917
2918    CurrentInstantiationScope->InstantiatedLocal(D, Inst);
2919    return cast<LabelDecl>(Inst);
2920  }
2921
2922  if (CXXRecordDecl *Record = dyn_cast<CXXRecordDecl>(D)) {
2923    if (!Record->isDependentContext())
2924      return D;
2925
2926    // If the RecordDecl is actually the injected-class-name or a
2927    // "templated" declaration for a class template, class template
2928    // partial specialization, or a member class of a class template,
2929    // substitute into the injected-class-name of the class template
2930    // or partial specialization to find the new DeclContext.
2931    QualType T;
2932    ClassTemplateDecl *ClassTemplate = Record->getDescribedClassTemplate();
2933
2934    if (ClassTemplate) {
2935      T = ClassTemplate->getInjectedClassNameSpecialization();
2936    } else if (ClassTemplatePartialSpecializationDecl *PartialSpec
2937                 = dyn_cast<ClassTemplatePartialSpecializationDecl>(Record)) {
2938      ClassTemplate = PartialSpec->getSpecializedTemplate();
2939
2940      // If we call SubstType with an InjectedClassNameType here we
2941      // can end up in an infinite loop.
2942      T = Context.getTypeDeclType(Record);
2943      assert(isa<InjectedClassNameType>(T) &&
2944             "type of partial specialization is not an InjectedClassNameType");
2945      T = cast<InjectedClassNameType>(T)->getInjectedSpecializationType();
2946    }
2947
2948    if (!T.isNull()) {
2949      // Substitute into the injected-class-name to get the type
2950      // corresponding to the instantiation we want, which may also be
2951      // the current instantiation (if we're in a template
2952      // definition). This substitution should never fail, since we
2953      // know we can instantiate the injected-class-name or we
2954      // wouldn't have gotten to the injected-class-name!
2955
2956      // FIXME: Can we use the CurrentInstantiationScope to avoid this
2957      // extra instantiation in the common case?
2958      T = SubstType(T, TemplateArgs, Loc, DeclarationName());
2959      assert(!T.isNull() && "Instantiation of injected-class-name cannot fail.");
2960
2961      if (!T->isDependentType()) {
2962        assert(T->isRecordType() && "Instantiation must produce a record type");
2963        return T->getAs<RecordType>()->getDecl();
2964      }
2965
2966      // We are performing "partial" template instantiation to create
2967      // the member declarations for the members of a class template
2968      // specialization. Therefore, D is actually referring to something
2969      // in the current instantiation. Look through the current
2970      // context, which contains actual instantiations, to find the
2971      // instantiation of the "current instantiation" that D refers
2972      // to.
2973      bool SawNonDependentContext = false;
2974      for (DeclContext *DC = CurContext; !DC->isFileContext();
2975           DC = DC->getParent()) {
2976        if (ClassTemplateSpecializationDecl *Spec
2977                          = dyn_cast<ClassTemplateSpecializationDecl>(DC))
2978          if (isInstantiationOf(ClassTemplate,
2979                                Spec->getSpecializedTemplate()))
2980            return Spec;
2981
2982        if (!DC->isDependentContext())
2983          SawNonDependentContext = true;
2984      }
2985
2986      // We're performing "instantiation" of a member of the current
2987      // instantiation while we are type-checking the
2988      // definition. Compute the declaration context and return that.
2989      assert(!SawNonDependentContext &&
2990             "No dependent context while instantiating record");
2991      DeclContext *DC = computeDeclContext(T);
2992      assert(DC &&
2993             "Unable to find declaration for the current instantiation");
2994      return cast<CXXRecordDecl>(DC);
2995    }
2996
2997    // Fall through to deal with other dependent record types (e.g.,
2998    // anonymous unions in class templates).
2999  }
3000
3001  if (!ParentDC->isDependentContext())
3002    return D;
3003
3004  ParentDC = FindInstantiatedContext(Loc, ParentDC, TemplateArgs);
3005  if (!ParentDC)
3006    return 0;
3007
3008  if (ParentDC != D->getDeclContext()) {
3009    // We performed some kind of instantiation in the parent context,
3010    // so now we need to look into the instantiated parent context to
3011    // find the instantiation of the declaration D.
3012
3013    // If our context used to be dependent, we may need to instantiate
3014    // it before performing lookup into that context.
3015    bool IsBeingInstantiated = false;
3016    if (CXXRecordDecl *Spec = dyn_cast<CXXRecordDecl>(ParentDC)) {
3017      if (!Spec->isDependentContext()) {
3018        QualType T = Context.getTypeDeclType(Spec);
3019        const RecordType *Tag = T->getAs<RecordType>();
3020        assert(Tag && "type of non-dependent record is not a RecordType");
3021        if (Tag->isBeingDefined())
3022          IsBeingInstantiated = true;
3023        if (!Tag->isBeingDefined() &&
3024            RequireCompleteType(Loc, T, diag::err_incomplete_type))
3025          return 0;
3026
3027        ParentDC = Tag->getDecl();
3028      }
3029    }
3030
3031    NamedDecl *Result = 0;
3032    if (D->getDeclName()) {
3033      DeclContext::lookup_result Found = ParentDC->lookup(D->getDeclName());
3034      Result = findInstantiationOf(Context, D, Found.first, Found.second);
3035    } else {
3036      // Since we don't have a name for the entity we're looking for,
3037      // our only option is to walk through all of the declarations to
3038      // find that name. This will occur in a few cases:
3039      //
3040      //   - anonymous struct/union within a template
3041      //   - unnamed class/struct/union/enum within a template
3042      //
3043      // FIXME: Find a better way to find these instantiations!
3044      Result = findInstantiationOf(Context, D,
3045                                   ParentDC->decls_begin(),
3046                                   ParentDC->decls_end());
3047    }
3048
3049    if (!Result) {
3050      if (isa<UsingShadowDecl>(D)) {
3051        // UsingShadowDecls can instantiate to nothing because of using hiding.
3052      } else if (Diags.hasErrorOccurred()) {
3053        // We've already complained about something, so most likely this
3054        // declaration failed to instantiate. There's no point in complaining
3055        // further, since this is normal in invalid code.
3056      } else if (IsBeingInstantiated) {
3057        // The class in which this member exists is currently being
3058        // instantiated, and we haven't gotten around to instantiating this
3059        // member yet. This can happen when the code uses forward declarations
3060        // of member classes, and introduces ordering dependencies via
3061        // template instantiation.
3062        Diag(Loc, diag::err_member_not_yet_instantiated)
3063          << D->getDeclName()
3064          << Context.getTypeDeclType(cast<CXXRecordDecl>(ParentDC));
3065        Diag(D->getLocation(), diag::note_non_instantiated_member_here);
3066      } else {
3067        // We should have found something, but didn't.
3068        llvm_unreachable("Unable to find instantiation of declaration!");
3069      }
3070    }
3071
3072    D = Result;
3073  }
3074
3075  return D;
3076}
3077
3078/// \brief Performs template instantiation for all implicit template
3079/// instantiations we have seen until this point.
3080void Sema::PerformPendingInstantiations(bool LocalOnly) {
3081  while (!PendingLocalImplicitInstantiations.empty() ||
3082         (!LocalOnly && !PendingInstantiations.empty())) {
3083    PendingImplicitInstantiation Inst;
3084
3085    if (PendingLocalImplicitInstantiations.empty()) {
3086      Inst = PendingInstantiations.front();
3087      PendingInstantiations.pop_front();
3088    } else {
3089      Inst = PendingLocalImplicitInstantiations.front();
3090      PendingLocalImplicitInstantiations.pop_front();
3091    }
3092
3093    // Instantiate function definitions
3094    if (FunctionDecl *Function = dyn_cast<FunctionDecl>(Inst.first)) {
3095      PrettyDeclStackTraceEntry CrashInfo(*this, Function, SourceLocation(),
3096                                          "instantiating function definition");
3097      bool DefinitionRequired = Function->getTemplateSpecializationKind() ==
3098                                TSK_ExplicitInstantiationDefinition;
3099      InstantiateFunctionDefinition(/*FIXME:*/Inst.second, Function, true,
3100                                    DefinitionRequired);
3101      continue;
3102    }
3103
3104    // Instantiate static data member definitions.
3105    VarDecl *Var = cast<VarDecl>(Inst.first);
3106    assert(Var->isStaticDataMember() && "Not a static data member?");
3107
3108    // Don't try to instantiate declarations if the most recent redeclaration
3109    // is invalid.
3110    if (Var->getMostRecentDeclaration()->isInvalidDecl())
3111      continue;
3112
3113    // Check if the most recent declaration has changed the specialization kind
3114    // and removed the need for implicit instantiation.
3115    switch (Var->getMostRecentDeclaration()->getTemplateSpecializationKind()) {
3116    case TSK_Undeclared:
3117      assert(false && "Cannot instantitiate an undeclared specialization.");
3118    case TSK_ExplicitInstantiationDeclaration:
3119    case TSK_ExplicitSpecialization:
3120      continue;  // No longer need to instantiate this type.
3121    case TSK_ExplicitInstantiationDefinition:
3122      // We only need an instantiation if the pending instantiation *is* the
3123      // explicit instantiation.
3124      if (Var != Var->getMostRecentDeclaration()) continue;
3125    case TSK_ImplicitInstantiation:
3126      break;
3127    }
3128
3129    PrettyDeclStackTraceEntry CrashInfo(*this, Var, Var->getLocation(),
3130                                        "instantiating static data member "
3131                                        "definition");
3132
3133    bool DefinitionRequired = Var->getTemplateSpecializationKind() ==
3134                              TSK_ExplicitInstantiationDefinition;
3135    InstantiateStaticDataMemberDefinition(/*FIXME:*/Inst.second, Var, true,
3136                                          DefinitionRequired);
3137  }
3138}
3139
3140void Sema::PerformDependentDiagnostics(const DeclContext *Pattern,
3141                       const MultiLevelTemplateArgumentList &TemplateArgs) {
3142  for (DeclContext::ddiag_iterator I = Pattern->ddiag_begin(),
3143         E = Pattern->ddiag_end(); I != E; ++I) {
3144    DependentDiagnostic *DD = *I;
3145
3146    switch (DD->getKind()) {
3147    case DependentDiagnostic::Access:
3148      HandleDependentAccessCheck(*DD, TemplateArgs);
3149      break;
3150    }
3151  }
3152}
3153