SemaTemplateInstantiateDecl.cpp revision 4fb86f8c4585e53c21c847ad3de9e3b2de123cd9 
1//===--- SemaTemplateInstantiateDecl.cpp - C++ Template Decl Instantiation ===/
2//
3//                     The LLVM Compiler Infrastructure
4//
5// This file is distributed under the University of Illinois Open Source
6// License. See LICENSE.TXT for details.
7//===----------------------------------------------------------------------===/
8//
9//  This file implements C++ template instantiation for declarations.
10//
11//===----------------------------------------------------------------------===/
12#include "clang/Sema/SemaInternal.h"
13#include "clang/Sema/Lookup.h"
14#include "clang/Sema/PrettyDeclStackTrace.h"
15#include "clang/Sema/Template.h"
16#include "clang/AST/ASTConsumer.h"
17#include "clang/AST/ASTContext.h"
18#include "clang/AST/DeclTemplate.h"
19#include "clang/AST/DeclVisitor.h"
20#include "clang/AST/DependentDiagnostic.h"
21#include "clang/AST/Expr.h"
22#include "clang/AST/ExprCXX.h"
23#include "clang/AST/TypeLoc.h"
24#include "clang/Lex/Preprocessor.h"
25
26using namespace clang;
27
28bool TemplateDeclInstantiator::SubstQualifier(const DeclaratorDecl *OldDecl,
29                                              DeclaratorDecl *NewDecl) {
30  if (!OldDecl->getQualifierLoc())
31    return false;
32
33  NestedNameSpecifierLoc NewQualifierLoc
34    = SemaRef.SubstNestedNameSpecifierLoc(OldDecl->getQualifierLoc(),
35                                          TemplateArgs);
36
37  if (!NewQualifierLoc)
38    return true;
39
40  NewDecl->setQualifierInfo(NewQualifierLoc);
41  return false;
42}
43
44bool TemplateDeclInstantiator::SubstQualifier(const TagDecl *OldDecl,
45                                              TagDecl *NewDecl) {
46  if (!OldDecl->getQualifierLoc())
47    return false;
48
49  NestedNameSpecifierLoc NewQualifierLoc
50  = SemaRef.SubstNestedNameSpecifierLoc(OldDecl->getQualifierLoc(),
51                                        TemplateArgs);
52
53  if (!NewQualifierLoc)
54    return true;
55
56  NewDecl->setQualifierInfo(NewQualifierLoc);
57  return false;
58}
59
60// FIXME: Is this still too simple?
61void Sema::InstantiateAttrs(const MultiLevelTemplateArgumentList &TemplateArgs,
62                            Decl *Tmpl, Decl *New) {
63  for (AttrVec::const_iterator i = Tmpl->attr_begin(), e = Tmpl->attr_end();
64       i != e; ++i) {
65    const Attr *TmplAttr = *i;
66    // FIXME: This should be generalized to more than just the AlignedAttr.
67    if (const AlignedAttr *Aligned = dyn_cast<AlignedAttr>(TmplAttr)) {
68      if (Aligned->isAlignmentDependent()) {
69        // The alignment expression is not potentially evaluated.
70        EnterExpressionEvaluationContext Unevaluated(*this,
71                                                     Sema::Unevaluated);
72
73        if (Aligned->isAlignmentExpr()) {
74          ExprResult Result = SubstExpr(Aligned->getAlignmentExpr(),
75                                        TemplateArgs);
76          if (!Result.isInvalid())
77            AddAlignedAttr(Aligned->getLocation(), New, Result.takeAs<Expr>());
78        }
79        else {
80          TypeSourceInfo *Result = SubstType(Aligned->getAlignmentType(),
81                                             TemplateArgs,
82                                             Aligned->getLocation(),
83                                             DeclarationName());
84          if (Result)
85            AddAlignedAttr(Aligned->getLocation(), New, Result);
86        }
87        continue;
88      }
89    }
90
91    // FIXME: Is cloning correct for all attributes?
92    Attr *NewAttr = TmplAttr->clone(Context);
93    New->addAttr(NewAttr);
94  }
95}
96
97Decl *
98TemplateDeclInstantiator::VisitTranslationUnitDecl(TranslationUnitDecl *D) {
99  assert(false && "Translation units cannot be instantiated");
100  return D;
101}
102
103Decl *
104TemplateDeclInstantiator::VisitLabelDecl(LabelDecl *D) {
105  LabelDecl *Inst = LabelDecl::Create(SemaRef.Context, Owner, D->getLocation(),
106                                      D->getIdentifier());
107  Owner->addDecl(Inst);
108  return Inst;
109}
110
111Decl *
112TemplateDeclInstantiator::VisitNamespaceDecl(NamespaceDecl *D) {
113  assert(false && "Namespaces cannot be instantiated");
114  return D;
115}
116
117Decl *
118TemplateDeclInstantiator::VisitNamespaceAliasDecl(NamespaceAliasDecl *D) {
119  NamespaceAliasDecl *Inst
120    = NamespaceAliasDecl::Create(SemaRef.Context, Owner,
121                                 D->getNamespaceLoc(),
122                                 D->getAliasLoc(),
123                                 D->getIdentifier(),
124                                 D->getQualifierLoc(),
125                                 D->getTargetNameLoc(),
126                                 D->getNamespace());
127  Owner->addDecl(Inst);
128  return Inst;
129}
130
131Decl *TemplateDeclInstantiator::VisitTypedefNameDecl(TypedefNameDecl *D,
132                                                     bool IsTypeAlias) {
133  bool Invalid = false;
134  TypeSourceInfo *DI = D->getTypeSourceInfo();
135  if (DI->getType()->isDependentType() ||
136      DI->getType()->isVariablyModifiedType()) {
137    DI = SemaRef.SubstType(DI, TemplateArgs,
138                           D->getLocation(), D->getDeclName());
139    if (!DI) {
140      Invalid = true;
141      DI = SemaRef.Context.getTrivialTypeSourceInfo(SemaRef.Context.IntTy);
142    }
143  } else {
144    SemaRef.MarkDeclarationsReferencedInType(D->getLocation(), DI->getType());
145  }
146
147  // Create the new typedef
148  TypedefNameDecl *Typedef;
149  if (IsTypeAlias)
150    Typedef = TypeAliasDecl::Create(SemaRef.Context, Owner, D->getLocStart(),
151                                    D->getLocation(), D->getIdentifier(), DI);
152  else
153    Typedef = TypedefDecl::Create(SemaRef.Context, Owner, D->getLocStart(),
154                                  D->getLocation(), D->getIdentifier(), DI);
155  if (Invalid)
156    Typedef->setInvalidDecl();
157
158  // If the old typedef was the name for linkage purposes of an anonymous
159  // tag decl, re-establish that relationship for the new typedef.
160  if (const TagType *oldTagType = D->getUnderlyingType()->getAs<TagType>()) {
161    TagDecl *oldTag = oldTagType->getDecl();
162    if (oldTag->getTypedefNameForAnonDecl() == D) {
163      TagDecl *newTag = DI->getType()->castAs<TagType>()->getDecl();
164      assert(!newTag->getIdentifier() && !newTag->getTypedefNameForAnonDecl());
165      newTag->setTypedefNameForAnonDecl(Typedef);
166    }
167  }
168
169  if (TypedefNameDecl *Prev = D->getPreviousDeclaration()) {
170    NamedDecl *InstPrev = SemaRef.FindInstantiatedDecl(D->getLocation(), Prev,
171                                                       TemplateArgs);
172    if (!InstPrev)
173      return 0;
174
175    Typedef->setPreviousDeclaration(cast<TypedefNameDecl>(InstPrev));
176  }
177
178  SemaRef.InstantiateAttrs(TemplateArgs, D, Typedef);
179
180  Typedef->setAccess(D->getAccess());
181  Owner->addDecl(Typedef);
182
183  return Typedef;
184}
185
186Decl *TemplateDeclInstantiator::VisitTypedefDecl(TypedefDecl *D) {
187  return VisitTypedefNameDecl(D, /*IsTypeAlias=*/false);
188}
189
190Decl *TemplateDeclInstantiator::VisitTypeAliasDecl(TypeAliasDecl *D) {
191  return VisitTypedefNameDecl(D, /*IsTypeAlias=*/true);
192}
193
194/// \brief Instantiate an initializer, breaking it into separate
195/// initialization arguments.
196///
197/// \param S The semantic analysis object.
198///
199/// \param Init The initializer to instantiate.
200///
201/// \param TemplateArgs Template arguments to be substituted into the
202/// initializer.
203///
204/// \param NewArgs Will be filled in with the instantiation arguments.
205///
206/// \returns true if an error occurred, false otherwise
207static bool InstantiateInitializer(Sema &S, Expr *Init,
208                            const MultiLevelTemplateArgumentList &TemplateArgs,
209                                   SourceLocation &LParenLoc,
210                                   ASTOwningVector<Expr*> &NewArgs,
211                                   SourceLocation &RParenLoc) {
212  NewArgs.clear();
213  LParenLoc = SourceLocation();
214  RParenLoc = SourceLocation();
215
216  if (!Init)
217    return false;
218
219  if (ExprWithCleanups *ExprTemp = dyn_cast<ExprWithCleanups>(Init))
220    Init = ExprTemp->getSubExpr();
221
222  while (CXXBindTemporaryExpr *Binder = dyn_cast<CXXBindTemporaryExpr>(Init))
223    Init = Binder->getSubExpr();
224
225  if (ImplicitCastExpr *ICE = dyn_cast<ImplicitCastExpr>(Init))
226    Init = ICE->getSubExprAsWritten();
227
228  if (ParenListExpr *ParenList = dyn_cast<ParenListExpr>(Init)) {
229    LParenLoc = ParenList->getLParenLoc();
230    RParenLoc = ParenList->getRParenLoc();
231    return S.SubstExprs(ParenList->getExprs(), ParenList->getNumExprs(),
232                        true, TemplateArgs, NewArgs);
233  }
234
235  if (CXXConstructExpr *Construct = dyn_cast<CXXConstructExpr>(Init)) {
236    if (!isa<CXXTemporaryObjectExpr>(Construct)) {
237      if (S.SubstExprs(Construct->getArgs(), Construct->getNumArgs(), true,
238                       TemplateArgs, NewArgs))
239        return true;
240
241      // FIXME: Fake locations!
242      LParenLoc = S.PP.getLocForEndOfToken(Init->getLocStart());
243      RParenLoc = LParenLoc;
244      return false;
245    }
246  }
247
248  ExprResult Result = S.SubstExpr(Init, TemplateArgs);
249  if (Result.isInvalid())
250    return true;
251
252  NewArgs.push_back(Result.takeAs<Expr>());
253  return false;
254}
255
256Decl *TemplateDeclInstantiator::VisitVarDecl(VarDecl *D) {
257  // If this is the variable for an anonymous struct or union,
258  // instantiate the anonymous struct/union type first.
259  if (const RecordType *RecordTy = D->getType()->getAs<RecordType>())
260    if (RecordTy->getDecl()->isAnonymousStructOrUnion())
261      if (!VisitCXXRecordDecl(cast<CXXRecordDecl>(RecordTy->getDecl())))
262        return 0;
263
264  // Do substitution on the type of the declaration
265  TypeSourceInfo *DI = SemaRef.SubstType(D->getTypeSourceInfo(),
266                                         TemplateArgs,
267                                         D->getTypeSpecStartLoc(),
268                                         D->getDeclName());
269  if (!DI)
270    return 0;
271
272  if (DI->getType()->isFunctionType()) {
273    SemaRef.Diag(D->getLocation(), diag::err_variable_instantiates_to_function)
274      << D->isStaticDataMember() << DI->getType();
275    return 0;
276  }
277
278  // Build the instantiated declaration
279  VarDecl *Var = VarDecl::Create(SemaRef.Context, Owner,
280                                 D->getInnerLocStart(),
281                                 D->getLocation(), D->getIdentifier(),
282                                 DI->getType(), DI,
283                                 D->getStorageClass(),
284                                 D->getStorageClassAsWritten());
285  Var->setThreadSpecified(D->isThreadSpecified());
286  Var->setCXXDirectInitializer(D->hasCXXDirectInitializer());
287  Var->setCXXForRangeDecl(D->isCXXForRangeDecl());
288
289  // Substitute the nested name specifier, if any.
290  if (SubstQualifier(D, Var))
291    return 0;
292
293  // If we are instantiating a static data member defined
294  // out-of-line, the instantiation will have the same lexical
295  // context (which will be a namespace scope) as the template.
296  if (D->isOutOfLine())
297    Var->setLexicalDeclContext(D->getLexicalDeclContext());
298
299  Var->setAccess(D->getAccess());
300
301  if (!D->isStaticDataMember()) {
302    Var->setUsed(D->isUsed(false));
303    Var->setReferenced(D->isReferenced());
304  }
305
306  // FIXME: In theory, we could have a previous declaration for variables that
307  // are not static data members.
308  bool Redeclaration = false;
309  // FIXME: having to fake up a LookupResult is dumb.
310  LookupResult Previous(SemaRef, Var->getDeclName(), Var->getLocation(),
311                        Sema::LookupOrdinaryName, Sema::ForRedeclaration);
312  if (D->isStaticDataMember())
313    SemaRef.LookupQualifiedName(Previous, Owner, false);
314  SemaRef.CheckVariableDeclaration(Var, Previous, Redeclaration);
315
316  if (D->isOutOfLine()) {
317    if (!D->isStaticDataMember())
318      D->getLexicalDeclContext()->addDecl(Var);
319    Owner->makeDeclVisibleInContext(Var);
320  } else {
321    Owner->addDecl(Var);
322    if (Owner->isFunctionOrMethod())
323      SemaRef.CurrentInstantiationScope->InstantiatedLocal(D, Var);
324  }
325  SemaRef.InstantiateAttrs(TemplateArgs, D, Var);
326
327  // Link instantiations of static data members back to the template from
328  // which they were instantiated.
329  if (Var->isStaticDataMember())
330    SemaRef.Context.setInstantiatedFromStaticDataMember(Var, D,
331                                                     TSK_ImplicitInstantiation);
332
333  if (Var->getAnyInitializer()) {
334    // We already have an initializer in the class.
335  } else if (D->getInit()) {
336    if (Var->isStaticDataMember() && !D->isOutOfLine())
337      SemaRef.PushExpressionEvaluationContext(Sema::Unevaluated);
338    else
339      SemaRef.PushExpressionEvaluationContext(Sema::PotentiallyEvaluated);
340
341    // Instantiate the initializer.
342    SourceLocation LParenLoc, RParenLoc;
343    ASTOwningVector<Expr*> InitArgs(SemaRef);
344    if (!InstantiateInitializer(SemaRef, D->getInit(), TemplateArgs, LParenLoc,
345                                InitArgs, RParenLoc)) {
346      bool TypeMayContainAuto = true;
347      // Attach the initializer to the declaration, if we have one.
348      if (InitArgs.size() == 0)
349        SemaRef.ActOnUninitializedDecl(Var, TypeMayContainAuto);
350      else if (D->hasCXXDirectInitializer()) {
351        // Add the direct initializer to the declaration.
352        SemaRef.AddCXXDirectInitializerToDecl(Var,
353                                              LParenLoc,
354                                              move_arg(InitArgs),
355                                              RParenLoc,
356                                              TypeMayContainAuto);
357      } else {
358        assert(InitArgs.size() == 1);
359        Expr *Init = InitArgs.take()[0];
360        SemaRef.AddInitializerToDecl(Var, Init, false, TypeMayContainAuto);
361      }
362    } else {
363      // FIXME: Not too happy about invalidating the declaration
364      // because of a bogus initializer.
365      Var->setInvalidDecl();
366    }
367
368    SemaRef.PopExpressionEvaluationContext();
369  } else if ((!Var->isStaticDataMember() || Var->isOutOfLine()) &&
370             !Var->isCXXForRangeDecl())
371    SemaRef.ActOnUninitializedDecl(Var, false);
372
373  // Diagnose unused local variables.
374  if (!Var->isInvalidDecl() && Owner->isFunctionOrMethod() && !Var->isUsed())
375    SemaRef.DiagnoseUnusedDecl(Var);
376
377  return Var;
378}
379
380Decl *TemplateDeclInstantiator::VisitAccessSpecDecl(AccessSpecDecl *D) {
381  AccessSpecDecl* AD
382    = AccessSpecDecl::Create(SemaRef.Context, D->getAccess(), Owner,
383                             D->getAccessSpecifierLoc(), D->getColonLoc());
384  Owner->addHiddenDecl(AD);
385  return AD;
386}
387
388Decl *TemplateDeclInstantiator::VisitFieldDecl(FieldDecl *D) {
389  bool Invalid = false;
390  TypeSourceInfo *DI = D->getTypeSourceInfo();
391  if (DI->getType()->isDependentType() ||
392      DI->getType()->isVariablyModifiedType())  {
393    DI = SemaRef.SubstType(DI, TemplateArgs,
394                           D->getLocation(), D->getDeclName());
395    if (!DI) {
396      DI = D->getTypeSourceInfo();
397      Invalid = true;
398    } else if (DI->getType()->isFunctionType()) {
399      // C++ [temp.arg.type]p3:
400      //   If a declaration acquires a function type through a type
401      //   dependent on a template-parameter and this causes a
402      //   declaration that does not use the syntactic form of a
403      //   function declarator to have function type, the program is
404      //   ill-formed.
405      SemaRef.Diag(D->getLocation(), diag::err_field_instantiates_to_function)
406        << DI->getType();
407      Invalid = true;
408    }
409  } else {
410    SemaRef.MarkDeclarationsReferencedInType(D->getLocation(), DI->getType());
411  }
412
413  Expr *BitWidth = D->getBitWidth();
414  if (Invalid)
415    BitWidth = 0;
416  else if (BitWidth) {
417    // The bit-width expression is not potentially evaluated.
418    EnterExpressionEvaluationContext Unevaluated(SemaRef, Sema::Unevaluated);
419
420    ExprResult InstantiatedBitWidth
421      = SemaRef.SubstExpr(BitWidth, TemplateArgs);
422    if (InstantiatedBitWidth.isInvalid()) {
423      Invalid = true;
424      BitWidth = 0;
425    } else
426      BitWidth = InstantiatedBitWidth.takeAs<Expr>();
427  }
428
429  FieldDecl *Field = SemaRef.CheckFieldDecl(D->getDeclName(),
430                                            DI->getType(), DI,
431                                            cast<RecordDecl>(Owner),
432                                            D->getLocation(),
433                                            D->isMutable(),
434                                            BitWidth,
435                                            D->getTypeSpecStartLoc(),
436                                            D->getAccess(),
437                                            0);
438  if (!Field) {
439    cast<Decl>(Owner)->setInvalidDecl();
440    return 0;
441  }
442
443  SemaRef.InstantiateAttrs(TemplateArgs, D, Field);
444
445  if (Invalid)
446    Field->setInvalidDecl();
447
448  if (!Field->getDeclName()) {
449    // Keep track of where this decl came from.
450    SemaRef.Context.setInstantiatedFromUnnamedFieldDecl(Field, D);
451  }
452  if (CXXRecordDecl *Parent= dyn_cast<CXXRecordDecl>(Field->getDeclContext())) {
453    if (Parent->isAnonymousStructOrUnion() &&
454        Parent->getRedeclContext()->isFunctionOrMethod())
455      SemaRef.CurrentInstantiationScope->InstantiatedLocal(D, Field);
456  }
457
458  Field->setImplicit(D->isImplicit());
459  Field->setAccess(D->getAccess());
460  Owner->addDecl(Field);
461
462  return Field;
463}
464
465Decl *TemplateDeclInstantiator::VisitIndirectFieldDecl(IndirectFieldDecl *D) {
466  NamedDecl **NamedChain =
467    new (SemaRef.Context)NamedDecl*[D->getChainingSize()];
468
469  int i = 0;
470  for (IndirectFieldDecl::chain_iterator PI =
471       D->chain_begin(), PE = D->chain_end();
472       PI != PE; ++PI) {
473    NamedDecl *Next = SemaRef.FindInstantiatedDecl(D->getLocation(), *PI,
474                                              TemplateArgs);
475    if (!Next)
476      return 0;
477
478    NamedChain[i++] = Next;
479  }
480
481  QualType T = cast<FieldDecl>(NamedChain[i-1])->getType();
482  IndirectFieldDecl* IndirectField
483    = IndirectFieldDecl::Create(SemaRef.Context, Owner, D->getLocation(),
484                                D->getIdentifier(), T,
485                                NamedChain, D->getChainingSize());
486
487
488  IndirectField->setImplicit(D->isImplicit());
489  IndirectField->setAccess(D->getAccess());
490  Owner->addDecl(IndirectField);
491  return IndirectField;
492}
493
494Decl *TemplateDeclInstantiator::VisitFriendDecl(FriendDecl *D) {
495  // Handle friend type expressions by simply substituting template
496  // parameters into the pattern type and checking the result.
497  if (TypeSourceInfo *Ty = D->getFriendType()) {
498    TypeSourceInfo *InstTy;
499    // If this is an unsupported friend, don't bother substituting template
500    // arguments into it. The actual type referred to won't be used by any
501    // parts of Clang, and may not be valid for instantiating. Just use the
502    // same info for the instantiated friend.
503    if (D->isUnsupportedFriend()) {
504      InstTy = Ty;
505    } else {
506      InstTy = SemaRef.SubstType(Ty, TemplateArgs,
507                                 D->getLocation(), DeclarationName());
508    }
509    if (!InstTy)
510      return 0;
511
512    FriendDecl *FD = SemaRef.CheckFriendTypeDecl(D->getFriendLoc(), InstTy);
513    if (!FD)
514      return 0;
515
516    FD->setAccess(AS_public);
517    FD->setUnsupportedFriend(D->isUnsupportedFriend());
518    Owner->addDecl(FD);
519    return FD;
520  }
521
522  NamedDecl *ND = D->getFriendDecl();
523  assert(ND && "friend decl must be a decl or a type!");
524
525  // All of the Visit implementations for the various potential friend
526  // declarations have to be carefully written to work for friend
527  // objects, with the most important detail being that the target
528  // decl should almost certainly not be placed in Owner.
529  Decl *NewND = Visit(ND);
530  if (!NewND) return 0;
531
532  FriendDecl *FD =
533    FriendDecl::Create(SemaRef.Context, Owner, D->getLocation(),
534                       cast<NamedDecl>(NewND), D->getFriendLoc());
535  FD->setAccess(AS_public);
536  FD->setUnsupportedFriend(D->isUnsupportedFriend());
537  Owner->addDecl(FD);
538  return FD;
539}
540
541Decl *TemplateDeclInstantiator::VisitStaticAssertDecl(StaticAssertDecl *D) {
542  Expr *AssertExpr = D->getAssertExpr();
543
544  // The expression in a static assertion is not potentially evaluated.
545  EnterExpressionEvaluationContext Unevaluated(SemaRef, Sema::Unevaluated);
546
547  ExprResult InstantiatedAssertExpr
548    = SemaRef.SubstExpr(AssertExpr, TemplateArgs);
549  if (InstantiatedAssertExpr.isInvalid())
550    return 0;
551
552  ExprResult Message(D->getMessage());
553  D->getMessage();
554  return SemaRef.ActOnStaticAssertDeclaration(D->getLocation(),
555                                              InstantiatedAssertExpr.get(),
556                                              Message.get(),
557                                              D->getRParenLoc());
558}
559
560Decl *TemplateDeclInstantiator::VisitEnumDecl(EnumDecl *D) {
561  EnumDecl *Enum = EnumDecl::Create(SemaRef.Context, Owner, D->getLocStart(),
562                                    D->getLocation(), D->getIdentifier(),
563                                    /*PrevDecl=*/0, D->isScoped(),
564                                    D->isScopedUsingClassTag(), D->isFixed());
565  if (D->isFixed()) {
566    if (TypeSourceInfo* TI = D->getIntegerTypeSourceInfo()) {
567      // If we have type source information for the underlying type, it means it
568      // has been explicitly set by the user. Perform substitution on it before
569      // moving on.
570      SourceLocation UnderlyingLoc = TI->getTypeLoc().getBeginLoc();
571      Enum->setIntegerTypeSourceInfo(SemaRef.SubstType(TI,
572                                                       TemplateArgs,
573                                                       UnderlyingLoc,
574                                                       DeclarationName()));
575
576      if (!Enum->getIntegerTypeSourceInfo())
577        Enum->setIntegerType(SemaRef.Context.IntTy);
578    }
579    else {
580      assert(!D->getIntegerType()->isDependentType()
581             && "Dependent type without type source info");
582      Enum->setIntegerType(D->getIntegerType());
583    }
584  }
585
586  SemaRef.InstantiateAttrs(TemplateArgs, D, Enum);
587
588  Enum->setInstantiationOfMemberEnum(D);
589  Enum->setAccess(D->getAccess());
590  if (SubstQualifier(D, Enum)) return 0;
591  Owner->addDecl(Enum);
592  Enum->startDefinition();
593
594  if (D->getDeclContext()->isFunctionOrMethod())
595    SemaRef.CurrentInstantiationScope->InstantiatedLocal(D, Enum);
596
597  llvm::SmallVector<Decl*, 4> Enumerators;
598
599  EnumConstantDecl *LastEnumConst = 0;
600  for (EnumDecl::enumerator_iterator EC = D->enumerator_begin(),
601         ECEnd = D->enumerator_end();
602       EC != ECEnd; ++EC) {
603    // The specified value for the enumerator.
604    ExprResult Value = SemaRef.Owned((Expr *)0);
605    if (Expr *UninstValue = EC->getInitExpr()) {
606      // The enumerator's value expression is not potentially evaluated.
607      EnterExpressionEvaluationContext Unevaluated(SemaRef,
608                                                   Sema::Unevaluated);
609
610      Value = SemaRef.SubstExpr(UninstValue, TemplateArgs);
611    }
612
613    // Drop the initial value and continue.
614    bool isInvalid = false;
615    if (Value.isInvalid()) {
616      Value = SemaRef.Owned((Expr *)0);
617      isInvalid = true;
618    }
619
620    EnumConstantDecl *EnumConst
621      = SemaRef.CheckEnumConstant(Enum, LastEnumConst,
622                                  EC->getLocation(), EC->getIdentifier(),
623                                  Value.get());
624
625    if (isInvalid) {
626      if (EnumConst)
627        EnumConst->setInvalidDecl();
628      Enum->setInvalidDecl();
629    }
630
631    if (EnumConst) {
632      SemaRef.InstantiateAttrs(TemplateArgs, *EC, EnumConst);
633
634      EnumConst->setAccess(Enum->getAccess());
635      Enum->addDecl(EnumConst);
636      Enumerators.push_back(EnumConst);
637      LastEnumConst = EnumConst;
638
639      if (D->getDeclContext()->isFunctionOrMethod()) {
640        // If the enumeration is within a function or method, record the enum
641        // constant as a local.
642        SemaRef.CurrentInstantiationScope->InstantiatedLocal(*EC, EnumConst);
643      }
644    }
645  }
646
647  // FIXME: Fixup LBraceLoc and RBraceLoc
648  // FIXME: Empty Scope and AttributeList (required to handle attribute packed).
649  SemaRef.ActOnEnumBody(Enum->getLocation(), SourceLocation(), SourceLocation(),
650                        Enum,
651                        Enumerators.data(), Enumerators.size(),
652                        0, 0);
653
654  return Enum;
655}
656
657Decl *TemplateDeclInstantiator::VisitEnumConstantDecl(EnumConstantDecl *D) {
658  assert(false && "EnumConstantDecls can only occur within EnumDecls.");
659  return 0;
660}
661
662Decl *TemplateDeclInstantiator::VisitClassTemplateDecl(ClassTemplateDecl *D) {
663  bool isFriend = (D->getFriendObjectKind() != Decl::FOK_None);
664
665  // Create a local instantiation scope for this class template, which
666  // will contain the instantiations of the template parameters.
667  LocalInstantiationScope Scope(SemaRef);
668  TemplateParameterList *TempParams = D->getTemplateParameters();
669  TemplateParameterList *InstParams = SubstTemplateParams(TempParams);
670  if (!InstParams)
671    return NULL;
672
673  CXXRecordDecl *Pattern = D->getTemplatedDecl();
674
675  // Instantiate the qualifier.  We have to do this first in case
676  // we're a friend declaration, because if we are then we need to put
677  // the new declaration in the appropriate context.
678  NestedNameSpecifierLoc QualifierLoc = Pattern->getQualifierLoc();
679  if (QualifierLoc) {
680    QualifierLoc = SemaRef.SubstNestedNameSpecifierLoc(QualifierLoc,
681                                                       TemplateArgs);
682    if (!QualifierLoc)
683      return 0;
684  }
685
686  CXXRecordDecl *PrevDecl = 0;
687  ClassTemplateDecl *PrevClassTemplate = 0;
688
689  if (!isFriend && Pattern->getPreviousDeclaration()) {
690    DeclContext::lookup_result Found = Owner->lookup(Pattern->getDeclName());
691    if (Found.first != Found.second) {
692      PrevClassTemplate = dyn_cast<ClassTemplateDecl>(*Found.first);
693      if (PrevClassTemplate)
694        PrevDecl = PrevClassTemplate->getTemplatedDecl();
695    }
696  }
697
698  // If this isn't a friend, then it's a member template, in which
699  // case we just want to build the instantiation in the
700  // specialization.  If it is a friend, we want to build it in
701  // the appropriate context.
702  DeclContext *DC = Owner;
703  if (isFriend) {
704    if (QualifierLoc) {
705      CXXScopeSpec SS;
706      SS.Adopt(QualifierLoc);
707      DC = SemaRef.computeDeclContext(SS);
708      if (!DC) return 0;
709    } else {
710      DC = SemaRef.FindInstantiatedContext(Pattern->getLocation(),
711                                           Pattern->getDeclContext(),
712                                           TemplateArgs);
713    }
714
715    // Look for a previous declaration of the template in the owning
716    // context.
717    LookupResult R(SemaRef, Pattern->getDeclName(), Pattern->getLocation(),
718                   Sema::LookupOrdinaryName, Sema::ForRedeclaration);
719    SemaRef.LookupQualifiedName(R, DC);
720
721    if (R.isSingleResult()) {
722      PrevClassTemplate = R.getAsSingle<ClassTemplateDecl>();
723      if (PrevClassTemplate)
724        PrevDecl = PrevClassTemplate->getTemplatedDecl();
725    }
726
727    if (!PrevClassTemplate && QualifierLoc) {
728      SemaRef.Diag(Pattern->getLocation(), diag::err_not_tag_in_scope)
729        << D->getTemplatedDecl()->getTagKind() << Pattern->getDeclName() << DC
730        << QualifierLoc.getSourceRange();
731      return 0;
732    }
733
734    bool AdoptedPreviousTemplateParams = false;
735    if (PrevClassTemplate) {
736      bool Complain = true;
737
738      // HACK: libstdc++ 4.2.1 contains an ill-formed friend class
739      // template for struct std::tr1::__detail::_Map_base, where the
740      // template parameters of the friend declaration don't match the
741      // template parameters of the original declaration. In this one
742      // case, we don't complain about the ill-formed friend
743      // declaration.
744      if (isFriend && Pattern->getIdentifier() &&
745          Pattern->getIdentifier()->isStr("_Map_base") &&
746          DC->isNamespace() &&
747          cast<NamespaceDecl>(DC)->getIdentifier() &&
748          cast<NamespaceDecl>(DC)->getIdentifier()->isStr("__detail")) {
749        DeclContext *DCParent = DC->getParent();
750        if (DCParent->isNamespace() &&
751            cast<NamespaceDecl>(DCParent)->getIdentifier() &&
752            cast<NamespaceDecl>(DCParent)->getIdentifier()->isStr("tr1")) {
753          DeclContext *DCParent2 = DCParent->getParent();
754          if (DCParent2->isNamespace() &&
755              cast<NamespaceDecl>(DCParent2)->getIdentifier() &&
756              cast<NamespaceDecl>(DCParent2)->getIdentifier()->isStr("std") &&
757              DCParent2->getParent()->isTranslationUnit())
758            Complain = false;
759        }
760      }
761
762      TemplateParameterList *PrevParams
763        = PrevClassTemplate->getTemplateParameters();
764
765      // Make sure the parameter lists match.
766      if (!SemaRef.TemplateParameterListsAreEqual(InstParams, PrevParams,
767                                                  Complain,
768                                                  Sema::TPL_TemplateMatch)) {
769        if (Complain)
770          return 0;
771
772        AdoptedPreviousTemplateParams = true;
773        InstParams = PrevParams;
774      }
775
776      // Do some additional validation, then merge default arguments
777      // from the existing declarations.
778      if (!AdoptedPreviousTemplateParams &&
779          SemaRef.CheckTemplateParameterList(InstParams, PrevParams,
780                                             Sema::TPC_ClassTemplate))
781        return 0;
782    }
783  }
784
785  CXXRecordDecl *RecordInst
786    = CXXRecordDecl::Create(SemaRef.Context, Pattern->getTagKind(), DC,
787                            Pattern->getLocStart(), Pattern->getLocation(),
788                            Pattern->getIdentifier(), PrevDecl,
789                            /*DelayTypeCreation=*/true);
790
791  if (QualifierLoc)
792    RecordInst->setQualifierInfo(QualifierLoc);
793
794  ClassTemplateDecl *Inst
795    = ClassTemplateDecl::Create(SemaRef.Context, DC, D->getLocation(),
796                                D->getIdentifier(), InstParams, RecordInst,
797                                PrevClassTemplate);
798  RecordInst->setDescribedClassTemplate(Inst);
799
800  if (isFriend) {
801    if (PrevClassTemplate)
802      Inst->setAccess(PrevClassTemplate->getAccess());
803    else
804      Inst->setAccess(D->getAccess());
805
806    Inst->setObjectOfFriendDecl(PrevClassTemplate != 0);
807    // TODO: do we want to track the instantiation progeny of this
808    // friend target decl?
809  } else {
810    Inst->setAccess(D->getAccess());
811    if (!PrevClassTemplate)
812      Inst->setInstantiatedFromMemberTemplate(D);
813  }
814
815  // Trigger creation of the type for the instantiation.
816  SemaRef.Context.getInjectedClassNameType(RecordInst,
817                                    Inst->getInjectedClassNameSpecialization());
818
819  // Finish handling of friends.
820  if (isFriend) {
821    DC->makeDeclVisibleInContext(Inst, /*Recoverable*/ false);
822    return Inst;
823  }
824
825  Owner->addDecl(Inst);
826
827  if (!PrevClassTemplate) {
828    // Queue up any out-of-line partial specializations of this member
829    // class template; the client will force their instantiation once
830    // the enclosing class has been instantiated.
831    llvm::SmallVector<ClassTemplatePartialSpecializationDecl *, 4> PartialSpecs;
832    D->getPartialSpecializations(PartialSpecs);
833    for (unsigned I = 0, N = PartialSpecs.size(); I != N; ++I)
834      if (PartialSpecs[I]->isOutOfLine())
835        OutOfLinePartialSpecs.push_back(std::make_pair(Inst, PartialSpecs[I]));
836  }
837
838  return Inst;
839}
840
841Decl *
842TemplateDeclInstantiator::VisitClassTemplatePartialSpecializationDecl(
843                                   ClassTemplatePartialSpecializationDecl *D) {
844  ClassTemplateDecl *ClassTemplate = D->getSpecializedTemplate();
845
846  // Lookup the already-instantiated declaration in the instantiation
847  // of the class template and return that.
848  DeclContext::lookup_result Found
849    = Owner->lookup(ClassTemplate->getDeclName());
850  if (Found.first == Found.second)
851    return 0;
852
853  ClassTemplateDecl *InstClassTemplate
854    = dyn_cast<ClassTemplateDecl>(*Found.first);
855  if (!InstClassTemplate)
856    return 0;
857
858  if (ClassTemplatePartialSpecializationDecl *Result
859        = InstClassTemplate->findPartialSpecInstantiatedFromMember(D))
860    return Result;
861
862  return InstantiateClassTemplatePartialSpecialization(InstClassTemplate, D);
863}
864
865Decl *
866TemplateDeclInstantiator::VisitFunctionTemplateDecl(FunctionTemplateDecl *D) {
867  // Create a local instantiation scope for this function template, which
868  // will contain the instantiations of the template parameters and then get
869  // merged with the local instantiation scope for the function template
870  // itself.
871  LocalInstantiationScope Scope(SemaRef);
872
873  TemplateParameterList *TempParams = D->getTemplateParameters();
874  TemplateParameterList *InstParams = SubstTemplateParams(TempParams);
875  if (!InstParams)
876    return NULL;
877
878  FunctionDecl *Instantiated = 0;
879  if (CXXMethodDecl *DMethod = dyn_cast<CXXMethodDecl>(D->getTemplatedDecl()))
880    Instantiated = cast_or_null<FunctionDecl>(VisitCXXMethodDecl(DMethod,
881                                                                 InstParams));
882  else
883    Instantiated = cast_or_null<FunctionDecl>(VisitFunctionDecl(
884                                                          D->getTemplatedDecl(),
885                                                                InstParams));
886
887  if (!Instantiated)
888    return 0;
889
890  Instantiated->setAccess(D->getAccess());
891
892  // Link the instantiated function template declaration to the function
893  // template from which it was instantiated.
894  FunctionTemplateDecl *InstTemplate
895    = Instantiated->getDescribedFunctionTemplate();
896  InstTemplate->setAccess(D->getAccess());
897  assert(InstTemplate &&
898         "VisitFunctionDecl/CXXMethodDecl didn't create a template!");
899
900  bool isFriend = (InstTemplate->getFriendObjectKind() != Decl::FOK_None);
901
902  // Link the instantiation back to the pattern *unless* this is a
903  // non-definition friend declaration.
904  if (!InstTemplate->getInstantiatedFromMemberTemplate() &&
905      !(isFriend && !D->getTemplatedDecl()->isThisDeclarationADefinition()))
906    InstTemplate->setInstantiatedFromMemberTemplate(D);
907
908  // Make declarations visible in the appropriate context.
909  if (!isFriend)
910    Owner->addDecl(InstTemplate);
911
912  return InstTemplate;
913}
914
915Decl *TemplateDeclInstantiator::VisitCXXRecordDecl(CXXRecordDecl *D) {
916  CXXRecordDecl *PrevDecl = 0;
917  if (D->isInjectedClassName())
918    PrevDecl = cast<CXXRecordDecl>(Owner);
919  else if (D->getPreviousDeclaration()) {
920    NamedDecl *Prev = SemaRef.FindInstantiatedDecl(D->getLocation(),
921                                                   D->getPreviousDeclaration(),
922                                                   TemplateArgs);
923    if (!Prev) return 0;
924    PrevDecl = cast<CXXRecordDecl>(Prev);
925  }
926
927  CXXRecordDecl *Record
928    = CXXRecordDecl::Create(SemaRef.Context, D->getTagKind(), Owner,
929                            D->getLocStart(), D->getLocation(),
930                            D->getIdentifier(), PrevDecl);
931
932  // Substitute the nested name specifier, if any.
933  if (SubstQualifier(D, Record))
934    return 0;
935
936  Record->setImplicit(D->isImplicit());
937  // FIXME: Check against AS_none is an ugly hack to work around the issue that
938  // the tag decls introduced by friend class declarations don't have an access
939  // specifier. Remove once this area of the code gets sorted out.
940  if (D->getAccess() != AS_none)
941    Record->setAccess(D->getAccess());
942  if (!D->isInjectedClassName())
943    Record->setInstantiationOfMemberClass(D, TSK_ImplicitInstantiation);
944
945  // If the original function was part of a friend declaration,
946  // inherit its namespace state.
947  if (Decl::FriendObjectKind FOK = D->getFriendObjectKind())
948    Record->setObjectOfFriendDecl(FOK == Decl::FOK_Declared);
949
950  // Make sure that anonymous structs and unions are recorded.
951  if (D->isAnonymousStructOrUnion()) {
952    Record->setAnonymousStructOrUnion(true);
953    if (Record->getDeclContext()->getRedeclContext()->isFunctionOrMethod())
954      SemaRef.CurrentInstantiationScope->InstantiatedLocal(D, Record);
955  }
956
957  Owner->addDecl(Record);
958  return Record;
959}
960
961/// Normal class members are of more specific types and therefore
962/// don't make it here.  This function serves two purposes:
963///   1) instantiating function templates
964///   2) substituting friend declarations
965/// FIXME: preserve function definitions in case #2
966Decl *TemplateDeclInstantiator::VisitFunctionDecl(FunctionDecl *D,
967                                       TemplateParameterList *TemplateParams) {
968  // Check whether there is already a function template specialization for
969  // this declaration.
970  FunctionTemplateDecl *FunctionTemplate = D->getDescribedFunctionTemplate();
971  void *InsertPos = 0;
972  if (FunctionTemplate && !TemplateParams) {
973    std::pair<const TemplateArgument *, unsigned> Innermost
974      = TemplateArgs.getInnermost();
975
976    FunctionDecl *SpecFunc
977      = FunctionTemplate->findSpecialization(Innermost.first, Innermost.second,
978                                             InsertPos);
979
980    // If we already have a function template specialization, return it.
981    if (SpecFunc)
982      return SpecFunc;
983  }
984
985  bool isFriend;
986  if (FunctionTemplate)
987    isFriend = (FunctionTemplate->getFriendObjectKind() != Decl::FOK_None);
988  else
989    isFriend = (D->getFriendObjectKind() != Decl::FOK_None);
990
991  bool MergeWithParentScope = (TemplateParams != 0) ||
992    Owner->isFunctionOrMethod() ||
993    !(isa<Decl>(Owner) &&
994      cast<Decl>(Owner)->isDefinedOutsideFunctionOrMethod());
995  LocalInstantiationScope Scope(SemaRef, MergeWithParentScope);
996
997  llvm::SmallVector<ParmVarDecl *, 4> Params;
998  TypeSourceInfo *TInfo = D->getTypeSourceInfo();
999  TInfo = SubstFunctionType(D, Params);
1000  if (!TInfo)
1001    return 0;
1002  QualType T = TInfo->getType();
1003
1004  NestedNameSpecifierLoc QualifierLoc = D->getQualifierLoc();
1005  if (QualifierLoc) {
1006    QualifierLoc = SemaRef.SubstNestedNameSpecifierLoc(QualifierLoc,
1007                                                       TemplateArgs);
1008    if (!QualifierLoc)
1009      return 0;
1010  }
1011
1012  // If we're instantiating a local function declaration, put the result
1013  // in the owner;  otherwise we need to find the instantiated context.
1014  DeclContext *DC;
1015  if (D->getDeclContext()->isFunctionOrMethod())
1016    DC = Owner;
1017  else if (isFriend && QualifierLoc) {
1018    CXXScopeSpec SS;
1019    SS.Adopt(QualifierLoc);
1020    DC = SemaRef.computeDeclContext(SS);
1021    if (!DC) return 0;
1022  } else {
1023    DC = SemaRef.FindInstantiatedContext(D->getLocation(), D->getDeclContext(),
1024                                         TemplateArgs);
1025  }
1026
1027  FunctionDecl *Function =
1028      FunctionDecl::Create(SemaRef.Context, DC, D->getInnerLocStart(),
1029                           D->getLocation(), D->getDeclName(), T, TInfo,
1030                           D->getStorageClass(), D->getStorageClassAsWritten(),
1031                           D->isInlineSpecified(), D->hasWrittenPrototype());
1032
1033  if (QualifierLoc)
1034    Function->setQualifierInfo(QualifierLoc);
1035
1036  DeclContext *LexicalDC = Owner;
1037  if (!isFriend && D->isOutOfLine()) {
1038    assert(D->getDeclContext()->isFileContext());
1039    LexicalDC = D->getDeclContext();
1040  }
1041
1042  Function->setLexicalDeclContext(LexicalDC);
1043
1044  // Attach the parameters
1045  for (unsigned P = 0; P < Params.size(); ++P)
1046    if (Params[P])
1047      Params[P]->setOwningFunction(Function);
1048  Function->setParams(Params.data(), Params.size());
1049
1050  SourceLocation InstantiateAtPOI;
1051  if (TemplateParams) {
1052    // Our resulting instantiation is actually a function template, since we
1053    // are substituting only the outer template parameters. For example, given
1054    //
1055    //   template<typename T>
1056    //   struct X {
1057    //     template<typename U> friend void f(T, U);
1058    //   };
1059    //
1060    //   X<int> x;
1061    //
1062    // We are instantiating the friend function template "f" within X<int>,
1063    // which means substituting int for T, but leaving "f" as a friend function
1064    // template.
1065    // Build the function template itself.
1066    FunctionTemplate = FunctionTemplateDecl::Create(SemaRef.Context, DC,
1067                                                    Function->getLocation(),
1068                                                    Function->getDeclName(),
1069                                                    TemplateParams, Function);
1070    Function->setDescribedFunctionTemplate(FunctionTemplate);
1071
1072    FunctionTemplate->setLexicalDeclContext(LexicalDC);
1073
1074    if (isFriend && D->isThisDeclarationADefinition()) {
1075      // TODO: should we remember this connection regardless of whether
1076      // the friend declaration provided a body?
1077      FunctionTemplate->setInstantiatedFromMemberTemplate(
1078                                           D->getDescribedFunctionTemplate());
1079    }
1080  } else if (FunctionTemplate) {
1081    // Record this function template specialization.
1082    std::pair<const TemplateArgument *, unsigned> Innermost
1083      = TemplateArgs.getInnermost();
1084    Function->setFunctionTemplateSpecialization(FunctionTemplate,
1085                            TemplateArgumentList::CreateCopy(SemaRef.Context,
1086                                                             Innermost.first,
1087                                                             Innermost.second),
1088                                                InsertPos);
1089  } else if (isFriend && D->isThisDeclarationADefinition()) {
1090    // TODO: should we remember this connection regardless of whether
1091    // the friend declaration provided a body?
1092    Function->setInstantiationOfMemberFunction(D, TSK_ImplicitInstantiation);
1093  }
1094
1095  if (InitFunctionInstantiation(Function, D))
1096    Function->setInvalidDecl();
1097
1098  bool Redeclaration = false;
1099  bool isExplicitSpecialization = false;
1100
1101  LookupResult Previous(SemaRef, Function->getDeclName(), SourceLocation(),
1102                        Sema::LookupOrdinaryName, Sema::ForRedeclaration);
1103
1104  if (DependentFunctionTemplateSpecializationInfo *Info
1105        = D->getDependentSpecializationInfo()) {
1106    assert(isFriend && "non-friend has dependent specialization info?");
1107
1108    // This needs to be set now for future sanity.
1109    Function->setObjectOfFriendDecl(/*HasPrevious*/ true);
1110
1111    // Instantiate the explicit template arguments.
1112    TemplateArgumentListInfo ExplicitArgs(Info->getLAngleLoc(),
1113                                          Info->getRAngleLoc());
1114    if (SemaRef.Subst(Info->getTemplateArgs(), Info->getNumTemplateArgs(),
1115                      ExplicitArgs, TemplateArgs))
1116      return 0;
1117
1118    // Map the candidate templates to their instantiations.
1119    for (unsigned I = 0, E = Info->getNumTemplates(); I != E; ++I) {
1120      Decl *Temp = SemaRef.FindInstantiatedDecl(D->getLocation(),
1121                                                Info->getTemplate(I),
1122                                                TemplateArgs);
1123      if (!Temp) return 0;
1124
1125      Previous.addDecl(cast<FunctionTemplateDecl>(Temp));
1126    }
1127
1128    if (SemaRef.CheckFunctionTemplateSpecialization(Function,
1129                                                    &ExplicitArgs,
1130                                                    Previous))
1131      Function->setInvalidDecl();
1132
1133    isExplicitSpecialization = true;
1134
1135  } else if (TemplateParams || !FunctionTemplate) {
1136    // Look only into the namespace where the friend would be declared to
1137    // find a previous declaration. This is the innermost enclosing namespace,
1138    // as described in ActOnFriendFunctionDecl.
1139    SemaRef.LookupQualifiedName(Previous, DC);
1140
1141    // In C++, the previous declaration we find might be a tag type
1142    // (class or enum). In this case, the new declaration will hide the
1143    // tag type. Note that this does does not apply if we're declaring a
1144    // typedef (C++ [dcl.typedef]p4).
1145    if (Previous.isSingleTagDecl())
1146      Previous.clear();
1147  }
1148
1149  SemaRef.CheckFunctionDeclaration(/*Scope*/ 0, Function, Previous,
1150                                   isExplicitSpecialization, Redeclaration);
1151
1152  NamedDecl *PrincipalDecl = (TemplateParams
1153                              ? cast<NamedDecl>(FunctionTemplate)
1154                              : Function);
1155
1156  // If the original function was part of a friend declaration,
1157  // inherit its namespace state and add it to the owner.
1158  if (isFriend) {
1159    NamedDecl *PrevDecl;
1160    if (TemplateParams)
1161      PrevDecl = FunctionTemplate->getPreviousDeclaration();
1162    else
1163      PrevDecl = Function->getPreviousDeclaration();
1164
1165    PrincipalDecl->setObjectOfFriendDecl(PrevDecl != 0);
1166    DC->makeDeclVisibleInContext(PrincipalDecl, /*Recoverable=*/ false);
1167
1168    bool queuedInstantiation = false;
1169
1170    if (!SemaRef.getLangOptions().CPlusPlus0x &&
1171        D->isThisDeclarationADefinition()) {
1172      // Check for a function body.
1173      const FunctionDecl *Definition = 0;
1174      if (Function->hasBody(Definition) &&
1175          Definition->getTemplateSpecializationKind() == TSK_Undeclared) {
1176        SemaRef.Diag(Function->getLocation(), diag::err_redefinition)
1177          << Function->getDeclName();
1178        SemaRef.Diag(Definition->getLocation(), diag::note_previous_definition);
1179        Function->setInvalidDecl();
1180      }
1181      // Check for redefinitions due to other instantiations of this or
1182      // a similar friend function.
1183      else for (FunctionDecl::redecl_iterator R = Function->redecls_begin(),
1184                                           REnd = Function->redecls_end();
1185                R != REnd; ++R) {
1186        if (*R == Function)
1187          continue;
1188        switch (R->getFriendObjectKind()) {
1189        case Decl::FOK_None:
1190          if (!queuedInstantiation && R->isUsed(false)) {
1191            if (MemberSpecializationInfo *MSInfo
1192                = Function->getMemberSpecializationInfo()) {
1193              if (MSInfo->getPointOfInstantiation().isInvalid()) {
1194                SourceLocation Loc = R->getLocation(); // FIXME
1195                MSInfo->setPointOfInstantiation(Loc);
1196                SemaRef.PendingLocalImplicitInstantiations.push_back(
1197                                                 std::make_pair(Function, Loc));
1198                queuedInstantiation = true;
1199              }
1200            }
1201          }
1202          break;
1203        default:
1204          if (const FunctionDecl *RPattern
1205              = R->getTemplateInstantiationPattern())
1206            if (RPattern->hasBody(RPattern)) {
1207              SemaRef.Diag(Function->getLocation(), diag::err_redefinition)
1208                << Function->getDeclName();
1209              SemaRef.Diag(R->getLocation(), diag::note_previous_definition);
1210              Function->setInvalidDecl();
1211              break;
1212            }
1213        }
1214      }
1215    }
1216  }
1217
1218  if (Function->isOverloadedOperator() && !DC->isRecord() &&
1219      PrincipalDecl->isInIdentifierNamespace(Decl::IDNS_Ordinary))
1220    PrincipalDecl->setNonMemberOperator();
1221
1222  return Function;
1223}
1224
1225Decl *
1226TemplateDeclInstantiator::VisitCXXMethodDecl(CXXMethodDecl *D,
1227                                      TemplateParameterList *TemplateParams) {
1228  FunctionTemplateDecl *FunctionTemplate = D->getDescribedFunctionTemplate();
1229  void *InsertPos = 0;
1230  if (FunctionTemplate && !TemplateParams) {
1231    // We are creating a function template specialization from a function
1232    // template. Check whether there is already a function template
1233    // specialization for this particular set of template arguments.
1234    std::pair<const TemplateArgument *, unsigned> Innermost
1235      = TemplateArgs.getInnermost();
1236
1237    FunctionDecl *SpecFunc
1238      = FunctionTemplate->findSpecialization(Innermost.first, Innermost.second,
1239                                             InsertPos);
1240
1241    // If we already have a function template specialization, return it.
1242    if (SpecFunc)
1243      return SpecFunc;
1244  }
1245
1246  bool isFriend;
1247  if (FunctionTemplate)
1248    isFriend = (FunctionTemplate->getFriendObjectKind() != Decl::FOK_None);
1249  else
1250    isFriend = (D->getFriendObjectKind() != Decl::FOK_None);
1251
1252  bool MergeWithParentScope = (TemplateParams != 0) ||
1253    !(isa<Decl>(Owner) &&
1254      cast<Decl>(Owner)->isDefinedOutsideFunctionOrMethod());
1255  LocalInstantiationScope Scope(SemaRef, MergeWithParentScope);
1256
1257  // Instantiate enclosing template arguments for friends.
1258  llvm::SmallVector<TemplateParameterList *, 4> TempParamLists;
1259  unsigned NumTempParamLists = 0;
1260  if (isFriend && (NumTempParamLists = D->getNumTemplateParameterLists())) {
1261    TempParamLists.set_size(NumTempParamLists);
1262    for (unsigned I = 0; I != NumTempParamLists; ++I) {
1263      TemplateParameterList *TempParams = D->getTemplateParameterList(I);
1264      TemplateParameterList *InstParams = SubstTemplateParams(TempParams);
1265      if (!InstParams)
1266        return NULL;
1267      TempParamLists[I] = InstParams;
1268    }
1269  }
1270
1271  llvm::SmallVector<ParmVarDecl *, 4> Params;
1272  TypeSourceInfo *TInfo = D->getTypeSourceInfo();
1273  TInfo = SubstFunctionType(D, Params);
1274  if (!TInfo)
1275    return 0;
1276  QualType T = TInfo->getType();
1277
1278  // \brief If the type of this function, after ignoring parentheses,
1279  // is not *directly* a function type, then we're instantiating a function
1280  // that was declared via a typedef, e.g.,
1281  //
1282  //   typedef int functype(int, int);
1283  //   functype func;
1284  //
1285  // In this case, we'll just go instantiate the ParmVarDecls that we
1286  // synthesized in the method declaration.
1287  if (!isa<FunctionProtoType>(T.IgnoreParens())) {
1288    assert(!Params.size() && "Instantiating type could not yield parameters");
1289    llvm::SmallVector<QualType, 4> ParamTypes;
1290    if (SemaRef.SubstParmTypes(D->getLocation(), D->param_begin(),
1291                               D->getNumParams(), TemplateArgs, ParamTypes,
1292                               &Params))
1293      return 0;
1294  }
1295
1296  NestedNameSpecifierLoc QualifierLoc = D->getQualifierLoc();
1297  if (QualifierLoc) {
1298    QualifierLoc = SemaRef.SubstNestedNameSpecifierLoc(QualifierLoc,
1299                                                 TemplateArgs);
1300    if (!QualifierLoc)
1301      return 0;
1302  }
1303
1304  DeclContext *DC = Owner;
1305  if (isFriend) {
1306    if (QualifierLoc) {
1307      CXXScopeSpec SS;
1308      SS.Adopt(QualifierLoc);
1309      DC = SemaRef.computeDeclContext(SS);
1310
1311      if (DC && SemaRef.RequireCompleteDeclContext(SS, DC))
1312        return 0;
1313    } else {
1314      DC = SemaRef.FindInstantiatedContext(D->getLocation(),
1315                                           D->getDeclContext(),
1316                                           TemplateArgs);
1317    }
1318    if (!DC) return 0;
1319  }
1320
1321  // Build the instantiated method declaration.
1322  CXXRecordDecl *Record = cast<CXXRecordDecl>(DC);
1323  CXXMethodDecl *Method = 0;
1324
1325  SourceLocation StartLoc = D->getInnerLocStart();
1326  DeclarationNameInfo NameInfo
1327    = SemaRef.SubstDeclarationNameInfo(D->getNameInfo(), TemplateArgs);
1328  if (CXXConstructorDecl *Constructor = dyn_cast<CXXConstructorDecl>(D)) {
1329    Method = CXXConstructorDecl::Create(SemaRef.Context, Record,
1330                                        StartLoc, NameInfo, T, TInfo,
1331                                        Constructor->isExplicit(),
1332                                        Constructor->isInlineSpecified(),
1333                                        false);
1334  } else if (CXXDestructorDecl *Destructor = dyn_cast<CXXDestructorDecl>(D)) {
1335    Method = CXXDestructorDecl::Create(SemaRef.Context, Record,
1336                                       StartLoc, NameInfo, T, TInfo,
1337                                       Destructor->isInlineSpecified(),
1338                                       false);
1339  } else if (CXXConversionDecl *Conversion = dyn_cast<CXXConversionDecl>(D)) {
1340    Method = CXXConversionDecl::Create(SemaRef.Context, Record,
1341                                       StartLoc, NameInfo, T, TInfo,
1342                                       Conversion->isInlineSpecified(),
1343                                       Conversion->isExplicit(),
1344                                       Conversion->getLocEnd());
1345  } else {
1346    Method = CXXMethodDecl::Create(SemaRef.Context, Record,
1347                                   StartLoc, NameInfo, T, TInfo,
1348                                   D->isStatic(),
1349                                   D->getStorageClassAsWritten(),
1350                                   D->isInlineSpecified(),
1351                                   D->getLocEnd());
1352  }
1353
1354  if (QualifierLoc)
1355    Method->setQualifierInfo(QualifierLoc);
1356
1357  if (TemplateParams) {
1358    // Our resulting instantiation is actually a function template, since we
1359    // are substituting only the outer template parameters. For example, given
1360    //
1361    //   template<typename T>
1362    //   struct X {
1363    //     template<typename U> void f(T, U);
1364    //   };
1365    //
1366    //   X<int> x;
1367    //
1368    // We are instantiating the member template "f" within X<int>, which means
1369    // substituting int for T, but leaving "f" as a member function template.
1370    // Build the function template itself.
1371    FunctionTemplate = FunctionTemplateDecl::Create(SemaRef.Context, Record,
1372                                                    Method->getLocation(),
1373                                                    Method->getDeclName(),
1374                                                    TemplateParams, Method);
1375    if (isFriend) {
1376      FunctionTemplate->setLexicalDeclContext(Owner);
1377      FunctionTemplate->setObjectOfFriendDecl(true);
1378    } else if (D->isOutOfLine())
1379      FunctionTemplate->setLexicalDeclContext(D->getLexicalDeclContext());
1380    Method->setDescribedFunctionTemplate(FunctionTemplate);
1381  } else if (FunctionTemplate) {
1382    // Record this function template specialization.
1383    std::pair<const TemplateArgument *, unsigned> Innermost
1384      = TemplateArgs.getInnermost();
1385    Method->setFunctionTemplateSpecialization(FunctionTemplate,
1386                         TemplateArgumentList::CreateCopy(SemaRef.Context,
1387                                                          Innermost.first,
1388                                                          Innermost.second),
1389                                              InsertPos);
1390  } else if (!isFriend) {
1391    // Record that this is an instantiation of a member function.
1392    Method->setInstantiationOfMemberFunction(D, TSK_ImplicitInstantiation);
1393  }
1394
1395  // If we are instantiating a member function defined
1396  // out-of-line, the instantiation will have the same lexical
1397  // context (which will be a namespace scope) as the template.
1398  if (isFriend) {
1399    if (NumTempParamLists)
1400      Method->setTemplateParameterListsInfo(SemaRef.Context,
1401                                            NumTempParamLists,
1402                                            TempParamLists.data());
1403
1404    Method->setLexicalDeclContext(Owner);
1405    Method->setObjectOfFriendDecl(true);
1406  } else if (D->isOutOfLine())
1407    Method->setLexicalDeclContext(D->getLexicalDeclContext());
1408
1409  // Attach the parameters
1410  for (unsigned P = 0; P < Params.size(); ++P)
1411    Params[P]->setOwningFunction(Method);
1412  Method->setParams(Params.data(), Params.size());
1413
1414  if (InitMethodInstantiation(Method, D))
1415    Method->setInvalidDecl();
1416
1417  LookupResult Previous(SemaRef, NameInfo, Sema::LookupOrdinaryName,
1418                        Sema::ForRedeclaration);
1419
1420  if (!FunctionTemplate || TemplateParams || isFriend) {
1421    SemaRef.LookupQualifiedName(Previous, Record);
1422
1423    // In C++, the previous declaration we find might be a tag type
1424    // (class or enum). In this case, the new declaration will hide the
1425    // tag type. Note that this does does not apply if we're declaring a
1426    // typedef (C++ [dcl.typedef]p4).
1427    if (Previous.isSingleTagDecl())
1428      Previous.clear();
1429  }
1430
1431  bool Redeclaration = false;
1432  SemaRef.CheckFunctionDeclaration(0, Method, Previous, false, Redeclaration);
1433
1434  if (D->isPure())
1435    SemaRef.CheckPureMethod(Method, SourceRange());
1436
1437  Method->setAccess(D->getAccess());
1438
1439  SemaRef.CheckOverrideControl(Method);
1440
1441  if (FunctionTemplate) {
1442    // If there's a function template, let our caller handle it.
1443  } else if (Method->isInvalidDecl() && !Previous.empty()) {
1444    // Don't hide a (potentially) valid declaration with an invalid one.
1445  } else {
1446    NamedDecl *DeclToAdd = (TemplateParams
1447                            ? cast<NamedDecl>(FunctionTemplate)
1448                            : Method);
1449    if (isFriend)
1450      Record->makeDeclVisibleInContext(DeclToAdd);
1451    else
1452      Owner->addDecl(DeclToAdd);
1453  }
1454
1455  return Method;
1456}
1457
1458Decl *TemplateDeclInstantiator::VisitCXXConstructorDecl(CXXConstructorDecl *D) {
1459  return VisitCXXMethodDecl(D);
1460}
1461
1462Decl *TemplateDeclInstantiator::VisitCXXDestructorDecl(CXXDestructorDecl *D) {
1463  return VisitCXXMethodDecl(D);
1464}
1465
1466Decl *TemplateDeclInstantiator::VisitCXXConversionDecl(CXXConversionDecl *D) {
1467  return VisitCXXMethodDecl(D);
1468}
1469
1470ParmVarDecl *TemplateDeclInstantiator::VisitParmVarDecl(ParmVarDecl *D) {
1471  return SemaRef.SubstParmVarDecl(D, TemplateArgs, llvm::Optional<unsigned>());
1472}
1473
1474Decl *TemplateDeclInstantiator::VisitTemplateTypeParmDecl(
1475                                                    TemplateTypeParmDecl *D) {
1476  // TODO: don't always clone when decls are refcounted.
1477  assert(D->getTypeForDecl()->isTemplateTypeParmType());
1478
1479  TemplateTypeParmDecl *Inst =
1480    TemplateTypeParmDecl::Create(SemaRef.Context, Owner,
1481                                 D->getLocStart(), D->getLocation(),
1482                                 D->getDepth() - TemplateArgs.getNumLevels(),
1483                                 D->getIndex(), D->getIdentifier(),
1484                                 D->wasDeclaredWithTypename(),
1485                                 D->isParameterPack());
1486  Inst->setAccess(AS_public);
1487
1488  if (D->hasDefaultArgument())
1489    Inst->setDefaultArgument(D->getDefaultArgumentInfo(), false);
1490
1491  // Introduce this template parameter's instantiation into the instantiation
1492  // scope.
1493  SemaRef.CurrentInstantiationScope->InstantiatedLocal(D, Inst);
1494
1495  return Inst;
1496}
1497
1498Decl *TemplateDeclInstantiator::VisitNonTypeTemplateParmDecl(
1499                                                 NonTypeTemplateParmDecl *D) {
1500  // Substitute into the type of the non-type template parameter.
1501  TypeLoc TL = D->getTypeSourceInfo()->getTypeLoc();
1502  llvm::SmallVector<TypeSourceInfo *, 4> ExpandedParameterPackTypesAsWritten;
1503  llvm::SmallVector<QualType, 4> ExpandedParameterPackTypes;
1504  bool IsExpandedParameterPack = false;
1505  TypeSourceInfo *DI;
1506  QualType T;
1507  bool Invalid = false;
1508
1509  if (D->isExpandedParameterPack()) {
1510    // The non-type template parameter pack is an already-expanded pack
1511    // expansion of types. Substitute into each of the expanded types.
1512    ExpandedParameterPackTypes.reserve(D->getNumExpansionTypes());
1513    ExpandedParameterPackTypesAsWritten.reserve(D->getNumExpansionTypes());
1514    for (unsigned I = 0, N = D->getNumExpansionTypes(); I != N; ++I) {
1515      TypeSourceInfo *NewDI =SemaRef.SubstType(D->getExpansionTypeSourceInfo(I),
1516                                               TemplateArgs,
1517                                               D->getLocation(),
1518                                               D->getDeclName());
1519      if (!NewDI)
1520        return 0;
1521
1522      ExpandedParameterPackTypesAsWritten.push_back(NewDI);
1523      QualType NewT =SemaRef.CheckNonTypeTemplateParameterType(NewDI->getType(),
1524                                                              D->getLocation());
1525      if (NewT.isNull())
1526        return 0;
1527      ExpandedParameterPackTypes.push_back(NewT);
1528    }
1529
1530    IsExpandedParameterPack = true;
1531    DI = D->getTypeSourceInfo();
1532    T = DI->getType();
1533  } else if (isa<PackExpansionTypeLoc>(TL)) {
1534    // The non-type template parameter pack's type is a pack expansion of types.
1535    // Determine whether we need to expand this parameter pack into separate
1536    // types.
1537    PackExpansionTypeLoc Expansion = cast<PackExpansionTypeLoc>(TL);
1538    TypeLoc Pattern = Expansion.getPatternLoc();
1539    llvm::SmallVector<UnexpandedParameterPack, 2> Unexpanded;
1540    SemaRef.collectUnexpandedParameterPacks(Pattern, Unexpanded);
1541
1542    // Determine whether the set of unexpanded parameter packs can and should
1543    // be expanded.
1544    bool Expand = true;
1545    bool RetainExpansion = false;
1546    llvm::Optional<unsigned> OrigNumExpansions
1547      = Expansion.getTypePtr()->getNumExpansions();
1548    llvm::Optional<unsigned> NumExpansions = OrigNumExpansions;
1549    if (SemaRef.CheckParameterPacksForExpansion(Expansion.getEllipsisLoc(),
1550                                                Pattern.getSourceRange(),
1551                                                Unexpanded.data(),
1552                                                Unexpanded.size(),
1553                                                TemplateArgs,
1554                                                Expand, RetainExpansion,
1555                                                NumExpansions))
1556      return 0;
1557
1558    if (Expand) {
1559      for (unsigned I = 0; I != *NumExpansions; ++I) {
1560        Sema::ArgumentPackSubstitutionIndexRAII SubstIndex(SemaRef, I);
1561        TypeSourceInfo *NewDI = SemaRef.SubstType(Pattern, TemplateArgs,
1562                                                  D->getLocation(),
1563                                                  D->getDeclName());
1564        if (!NewDI)
1565          return 0;
1566
1567        ExpandedParameterPackTypesAsWritten.push_back(NewDI);
1568        QualType NewT = SemaRef.CheckNonTypeTemplateParameterType(
1569                                                              NewDI->getType(),
1570                                                              D->getLocation());
1571        if (NewT.isNull())
1572          return 0;
1573        ExpandedParameterPackTypes.push_back(NewT);
1574      }
1575
1576      // Note that we have an expanded parameter pack. The "type" of this
1577      // expanded parameter pack is the original expansion type, but callers
1578      // will end up using the expanded parameter pack types for type-checking.
1579      IsExpandedParameterPack = true;
1580      DI = D->getTypeSourceInfo();
1581      T = DI->getType();
1582    } else {
1583      // We cannot fully expand the pack expansion now, so substitute into the
1584      // pattern and create a new pack expansion type.
1585      Sema::ArgumentPackSubstitutionIndexRAII SubstIndex(SemaRef, -1);
1586      TypeSourceInfo *NewPattern = SemaRef.SubstType(Pattern, TemplateArgs,
1587                                                     D->getLocation(),
1588                                                     D->getDeclName());
1589      if (!NewPattern)
1590        return 0;
1591
1592      DI = SemaRef.CheckPackExpansion(NewPattern, Expansion.getEllipsisLoc(),
1593                                      NumExpansions);
1594      if (!DI)
1595        return 0;
1596
1597      T = DI->getType();
1598    }
1599  } else {
1600    // Simple case: substitution into a parameter that is not a parameter pack.
1601    DI = SemaRef.SubstType(D->getTypeSourceInfo(), TemplateArgs,
1602                           D->getLocation(), D->getDeclName());
1603    if (!DI)
1604      return 0;
1605
1606    // Check that this type is acceptable for a non-type template parameter.
1607    bool Invalid = false;
1608    T = SemaRef.CheckNonTypeTemplateParameterType(DI->getType(),
1609                                                  D->getLocation());
1610    if (T.isNull()) {
1611      T = SemaRef.Context.IntTy;
1612      Invalid = true;
1613    }
1614  }
1615
1616  NonTypeTemplateParmDecl *Param;
1617  if (IsExpandedParameterPack)
1618    Param = NonTypeTemplateParmDecl::Create(SemaRef.Context, Owner,
1619                                            D->getInnerLocStart(),
1620                                            D->getLocation(),
1621                                    D->getDepth() - TemplateArgs.getNumLevels(),
1622                                            D->getPosition(),
1623                                            D->getIdentifier(), T,
1624                                            DI,
1625                                            ExpandedParameterPackTypes.data(),
1626                                            ExpandedParameterPackTypes.size(),
1627                                    ExpandedParameterPackTypesAsWritten.data());
1628  else
1629    Param = NonTypeTemplateParmDecl::Create(SemaRef.Context, Owner,
1630                                            D->getInnerLocStart(),
1631                                            D->getLocation(),
1632                                    D->getDepth() - TemplateArgs.getNumLevels(),
1633                                            D->getPosition(),
1634                                            D->getIdentifier(), T,
1635                                            D->isParameterPack(), DI);
1636
1637  Param->setAccess(AS_public);
1638  if (Invalid)
1639    Param->setInvalidDecl();
1640
1641  Param->setDefaultArgument(D->getDefaultArgument(), false);
1642
1643  // Introduce this template parameter's instantiation into the instantiation
1644  // scope.
1645  SemaRef.CurrentInstantiationScope->InstantiatedLocal(D, Param);
1646  return Param;
1647}
1648
1649Decl *
1650TemplateDeclInstantiator::VisitTemplateTemplateParmDecl(
1651                                                  TemplateTemplateParmDecl *D) {
1652  // Instantiate the template parameter list of the template template parameter.
1653  TemplateParameterList *TempParams = D->getTemplateParameters();
1654  TemplateParameterList *InstParams;
1655  {
1656    // Perform the actual substitution of template parameters within a new,
1657    // local instantiation scope.
1658    LocalInstantiationScope Scope(SemaRef);
1659    InstParams = SubstTemplateParams(TempParams);
1660    if (!InstParams)
1661      return NULL;
1662  }
1663
1664  // Build the template template parameter.
1665  TemplateTemplateParmDecl *Param
1666    = TemplateTemplateParmDecl::Create(SemaRef.Context, Owner, D->getLocation(),
1667                                   D->getDepth() - TemplateArgs.getNumLevels(),
1668                                       D->getPosition(), D->isParameterPack(),
1669                                       D->getIdentifier(), InstParams);
1670  Param->setDefaultArgument(D->getDefaultArgument(), false);
1671  Param->setAccess(AS_public);
1672
1673  // Introduce this template parameter's instantiation into the instantiation
1674  // scope.
1675  SemaRef.CurrentInstantiationScope->InstantiatedLocal(D, Param);
1676
1677  return Param;
1678}
1679
1680Decl *TemplateDeclInstantiator::VisitUsingDirectiveDecl(UsingDirectiveDecl *D) {
1681  // Using directives are never dependent (and never contain any types or
1682  // expressions), so they require no explicit instantiation work.
1683
1684  UsingDirectiveDecl *Inst
1685    = UsingDirectiveDecl::Create(SemaRef.Context, Owner, D->getLocation(),
1686                                 D->getNamespaceKeyLocation(),
1687                                 D->getQualifierLoc(),
1688                                 D->getIdentLocation(),
1689                                 D->getNominatedNamespace(),
1690                                 D->getCommonAncestor());
1691  Owner->addDecl(Inst);
1692  return Inst;
1693}
1694
1695Decl *TemplateDeclInstantiator::VisitUsingDecl(UsingDecl *D) {
1696
1697  // The nested name specifier may be dependent, for example
1698  //     template <typename T> struct t {
1699  //       struct s1 { T f1(); };
1700  //       struct s2 : s1 { using s1::f1; };
1701  //     };
1702  //     template struct t<int>;
1703  // Here, in using s1::f1, s1 refers to t<T>::s1;
1704  // we need to substitute for t<int>::s1.
1705  NestedNameSpecifierLoc QualifierLoc
1706    = SemaRef.SubstNestedNameSpecifierLoc(D->getQualifierLoc(),
1707                                          TemplateArgs);
1708  if (!QualifierLoc)
1709    return 0;
1710
1711  // The name info is non-dependent, so no transformation
1712  // is required.
1713  DeclarationNameInfo NameInfo = D->getNameInfo();
1714
1715  // We only need to do redeclaration lookups if we're in a class
1716  // scope (in fact, it's not really even possible in non-class
1717  // scopes).
1718  bool CheckRedeclaration = Owner->isRecord();
1719
1720  LookupResult Prev(SemaRef, NameInfo, Sema::LookupUsingDeclName,
1721                    Sema::ForRedeclaration);
1722
1723  UsingDecl *NewUD = UsingDecl::Create(SemaRef.Context, Owner,
1724                                       D->getUsingLocation(),
1725                                       QualifierLoc,
1726                                       NameInfo,
1727                                       D->isTypeName());
1728
1729  CXXScopeSpec SS;
1730  SS.Adopt(QualifierLoc);
1731  if (CheckRedeclaration) {
1732    Prev.setHideTags(false);
1733    SemaRef.LookupQualifiedName(Prev, Owner);
1734
1735    // Check for invalid redeclarations.
1736    if (SemaRef.CheckUsingDeclRedeclaration(D->getUsingLocation(),
1737                                            D->isTypeName(), SS,
1738                                            D->getLocation(), Prev))
1739      NewUD->setInvalidDecl();
1740
1741  }
1742
1743  if (!NewUD->isInvalidDecl() &&
1744      SemaRef.CheckUsingDeclQualifier(D->getUsingLocation(), SS,
1745                                      D->getLocation()))
1746    NewUD->setInvalidDecl();
1747
1748  SemaRef.Context.setInstantiatedFromUsingDecl(NewUD, D);
1749  NewUD->setAccess(D->getAccess());
1750  Owner->addDecl(NewUD);
1751
1752  // Don't process the shadow decls for an invalid decl.
1753  if (NewUD->isInvalidDecl())
1754    return NewUD;
1755
1756  bool isFunctionScope = Owner->isFunctionOrMethod();
1757
1758  // Process the shadow decls.
1759  for (UsingDecl::shadow_iterator I = D->shadow_begin(), E = D->shadow_end();
1760         I != E; ++I) {
1761    UsingShadowDecl *Shadow = *I;
1762    NamedDecl *InstTarget =
1763      cast_or_null<NamedDecl>(SemaRef.FindInstantiatedDecl(
1764                                                          Shadow->getLocation(),
1765                                                        Shadow->getTargetDecl(),
1766                                                           TemplateArgs));
1767    if (!InstTarget)
1768      return 0;
1769
1770    if (CheckRedeclaration &&
1771        SemaRef.CheckUsingShadowDecl(NewUD, InstTarget, Prev))
1772      continue;
1773
1774    UsingShadowDecl *InstShadow
1775      = SemaRef.BuildUsingShadowDecl(/*Scope*/ 0, NewUD, InstTarget);
1776    SemaRef.Context.setInstantiatedFromUsingShadowDecl(InstShadow, Shadow);
1777
1778    if (isFunctionScope)
1779      SemaRef.CurrentInstantiationScope->InstantiatedLocal(Shadow, InstShadow);
1780  }
1781
1782  return NewUD;
1783}
1784
1785Decl *TemplateDeclInstantiator::VisitUsingShadowDecl(UsingShadowDecl *D) {
1786  // Ignore these;  we handle them in bulk when processing the UsingDecl.
1787  return 0;
1788}
1789
1790Decl * TemplateDeclInstantiator
1791    ::VisitUnresolvedUsingTypenameDecl(UnresolvedUsingTypenameDecl *D) {
1792  NestedNameSpecifierLoc QualifierLoc
1793    = SemaRef.SubstNestedNameSpecifierLoc(D->getQualifierLoc(),
1794                                          TemplateArgs);
1795  if (!QualifierLoc)
1796    return 0;
1797
1798  CXXScopeSpec SS;
1799  SS.Adopt(QualifierLoc);
1800
1801  // Since NameInfo refers to a typename, it cannot be a C++ special name.
1802  // Hence, no tranformation is required for it.
1803  DeclarationNameInfo NameInfo(D->getDeclName(), D->getLocation());
1804  NamedDecl *UD =
1805    SemaRef.BuildUsingDeclaration(/*Scope*/ 0, D->getAccess(),
1806                                  D->getUsingLoc(), SS, NameInfo, 0,
1807                                  /*instantiation*/ true,
1808                                  /*typename*/ true, D->getTypenameLoc());
1809  if (UD)
1810    SemaRef.Context.setInstantiatedFromUsingDecl(cast<UsingDecl>(UD), D);
1811
1812  return UD;
1813}
1814
1815Decl * TemplateDeclInstantiator
1816    ::VisitUnresolvedUsingValueDecl(UnresolvedUsingValueDecl *D) {
1817  NestedNameSpecifierLoc QualifierLoc
1818      = SemaRef.SubstNestedNameSpecifierLoc(D->getQualifierLoc(), TemplateArgs);
1819  if (!QualifierLoc)
1820    return 0;
1821
1822  CXXScopeSpec SS;
1823  SS.Adopt(QualifierLoc);
1824
1825  DeclarationNameInfo NameInfo
1826    = SemaRef.SubstDeclarationNameInfo(D->getNameInfo(), TemplateArgs);
1827
1828  NamedDecl *UD =
1829    SemaRef.BuildUsingDeclaration(/*Scope*/ 0, D->getAccess(),
1830                                  D->getUsingLoc(), SS, NameInfo, 0,
1831                                  /*instantiation*/ true,
1832                                  /*typename*/ false, SourceLocation());
1833  if (UD)
1834    SemaRef.Context.setInstantiatedFromUsingDecl(cast<UsingDecl>(UD), D);
1835
1836  return UD;
1837}
1838
1839Decl *Sema::SubstDecl(Decl *D, DeclContext *Owner,
1840                      const MultiLevelTemplateArgumentList &TemplateArgs) {
1841  TemplateDeclInstantiator Instantiator(*this, Owner, TemplateArgs);
1842  if (D->isInvalidDecl())
1843    return 0;
1844
1845  return Instantiator.Visit(D);
1846}
1847
1848/// \brief Instantiates a nested template parameter list in the current
1849/// instantiation context.
1850///
1851/// \param L The parameter list to instantiate
1852///
1853/// \returns NULL if there was an error
1854TemplateParameterList *
1855TemplateDeclInstantiator::SubstTemplateParams(TemplateParameterList *L) {
1856  // Get errors for all the parameters before bailing out.
1857  bool Invalid = false;
1858
1859  unsigned N = L->size();
1860  typedef llvm::SmallVector<NamedDecl *, 8> ParamVector;
1861  ParamVector Params;
1862  Params.reserve(N);
1863  for (TemplateParameterList::iterator PI = L->begin(), PE = L->end();
1864       PI != PE; ++PI) {
1865    NamedDecl *D = cast_or_null<NamedDecl>(Visit(*PI));
1866    Params.push_back(D);
1867    Invalid = Invalid || !D || D->isInvalidDecl();
1868  }
1869
1870  // Clean up if we had an error.
1871  if (Invalid)
1872    return NULL;
1873
1874  TemplateParameterList *InstL
1875    = TemplateParameterList::Create(SemaRef.Context, L->getTemplateLoc(),
1876                                    L->getLAngleLoc(), &Params.front(), N,
1877                                    L->getRAngleLoc());
1878  return InstL;
1879}
1880
1881/// \brief Instantiate the declaration of a class template partial
1882/// specialization.
1883///
1884/// \param ClassTemplate the (instantiated) class template that is partially
1885// specialized by the instantiation of \p PartialSpec.
1886///
1887/// \param PartialSpec the (uninstantiated) class template partial
1888/// specialization that we are instantiating.
1889///
1890/// \returns The instantiated partial specialization, if successful; otherwise,
1891/// NULL to indicate an error.
1892ClassTemplatePartialSpecializationDecl *
1893TemplateDeclInstantiator::InstantiateClassTemplatePartialSpecialization(
1894                                            ClassTemplateDecl *ClassTemplate,
1895                          ClassTemplatePartialSpecializationDecl *PartialSpec) {
1896  // Create a local instantiation scope for this class template partial
1897  // specialization, which will contain the instantiations of the template
1898  // parameters.
1899  LocalInstantiationScope Scope(SemaRef);
1900
1901  // Substitute into the template parameters of the class template partial
1902  // specialization.
1903  TemplateParameterList *TempParams = PartialSpec->getTemplateParameters();
1904  TemplateParameterList *InstParams = SubstTemplateParams(TempParams);
1905  if (!InstParams)
1906    return 0;
1907
1908  // Substitute into the template arguments of the class template partial
1909  // specialization.
1910  TemplateArgumentListInfo InstTemplateArgs; // no angle locations
1911  if (SemaRef.Subst(PartialSpec->getTemplateArgsAsWritten(),
1912                    PartialSpec->getNumTemplateArgsAsWritten(),
1913                    InstTemplateArgs, TemplateArgs))
1914    return 0;
1915
1916  // Check that the template argument list is well-formed for this
1917  // class template.
1918  llvm::SmallVector<TemplateArgument, 4> Converted;
1919  if (SemaRef.CheckTemplateArgumentList(ClassTemplate,
1920                                        PartialSpec->getLocation(),
1921                                        InstTemplateArgs,
1922                                        false,
1923                                        Converted))
1924    return 0;
1925
1926  // Figure out where to insert this class template partial specialization
1927  // in the member template's set of class template partial specializations.
1928  void *InsertPos = 0;
1929  ClassTemplateSpecializationDecl *PrevDecl
1930    = ClassTemplate->findPartialSpecialization(Converted.data(),
1931                                               Converted.size(), InsertPos);
1932
1933  // Build the canonical type that describes the converted template
1934  // arguments of the class template partial specialization.
1935  QualType CanonType
1936    = SemaRef.Context.getTemplateSpecializationType(TemplateName(ClassTemplate),
1937                                                    Converted.data(),
1938                                                    Converted.size());
1939
1940  // Build the fully-sugared type for this class template
1941  // specialization as the user wrote in the specialization
1942  // itself. This means that we'll pretty-print the type retrieved
1943  // from the specialization's declaration the way that the user
1944  // actually wrote the specialization, rather than formatting the
1945  // name based on the "canonical" representation used to store the
1946  // template arguments in the specialization.
1947  TypeSourceInfo *WrittenTy
1948    = SemaRef.Context.getTemplateSpecializationTypeInfo(
1949                                                    TemplateName(ClassTemplate),
1950                                                    PartialSpec->getLocation(),
1951                                                    InstTemplateArgs,
1952                                                    CanonType);
1953
1954  if (PrevDecl) {
1955    // We've already seen a partial specialization with the same template
1956    // parameters and template arguments. This can happen, for example, when
1957    // substituting the outer template arguments ends up causing two
1958    // class template partial specializations of a member class template
1959    // to have identical forms, e.g.,
1960    //
1961    //   template<typename T, typename U>
1962    //   struct Outer {
1963    //     template<typename X, typename Y> struct Inner;
1964    //     template<typename Y> struct Inner<T, Y>;
1965    //     template<typename Y> struct Inner<U, Y>;
1966    //   };
1967    //
1968    //   Outer<int, int> outer; // error: the partial specializations of Inner
1969    //                          // have the same signature.
1970    SemaRef.Diag(PartialSpec->getLocation(), diag::err_partial_spec_redeclared)
1971      << WrittenTy->getType();
1972    SemaRef.Diag(PrevDecl->getLocation(), diag::note_prev_partial_spec_here)
1973      << SemaRef.Context.getTypeDeclType(PrevDecl);
1974    return 0;
1975  }
1976
1977
1978  // Create the class template partial specialization declaration.
1979  ClassTemplatePartialSpecializationDecl *InstPartialSpec
1980    = ClassTemplatePartialSpecializationDecl::Create(SemaRef.Context,
1981                                                     PartialSpec->getTagKind(),
1982                                                     Owner,
1983                                                     PartialSpec->getLocStart(),
1984                                                     PartialSpec->getLocation(),
1985                                                     InstParams,
1986                                                     ClassTemplate,
1987                                                     Converted.data(),
1988                                                     Converted.size(),
1989                                                     InstTemplateArgs,
1990                                                     CanonType,
1991                                                     0,
1992                             ClassTemplate->getNextPartialSpecSequenceNumber());
1993  // Substitute the nested name specifier, if any.
1994  if (SubstQualifier(PartialSpec, InstPartialSpec))
1995    return 0;
1996
1997  InstPartialSpec->setInstantiatedFromMember(PartialSpec);
1998  InstPartialSpec->setTypeAsWritten(WrittenTy);
1999
2000  // Add this partial specialization to the set of class template partial
2001  // specializations.
2002  ClassTemplate->AddPartialSpecialization(InstPartialSpec, InsertPos);
2003  return InstPartialSpec;
2004}
2005
2006TypeSourceInfo*
2007TemplateDeclInstantiator::SubstFunctionType(FunctionDecl *D,
2008                              llvm::SmallVectorImpl<ParmVarDecl *> &Params) {
2009  TypeSourceInfo *OldTInfo = D->getTypeSourceInfo();
2010  assert(OldTInfo && "substituting function without type source info");
2011  assert(Params.empty() && "parameter vector is non-empty at start");
2012  TypeSourceInfo *NewTInfo
2013    = SemaRef.SubstFunctionDeclType(OldTInfo, TemplateArgs,
2014                                    D->getTypeSpecStartLoc(),
2015                                    D->getDeclName());
2016  if (!NewTInfo)
2017    return 0;
2018
2019  if (NewTInfo != OldTInfo) {
2020    // Get parameters from the new type info.
2021    TypeLoc OldTL = OldTInfo->getTypeLoc().IgnoreParens();
2022    if (FunctionProtoTypeLoc *OldProtoLoc
2023                                  = dyn_cast<FunctionProtoTypeLoc>(&OldTL)) {
2024      TypeLoc NewTL = NewTInfo->getTypeLoc().IgnoreParens();
2025      FunctionProtoTypeLoc *NewProtoLoc = cast<FunctionProtoTypeLoc>(&NewTL);
2026      assert(NewProtoLoc && "Missing prototype?");
2027      unsigned NewIdx = 0, NumNewParams = NewProtoLoc->getNumArgs();
2028      for (unsigned OldIdx = 0, NumOldParams = OldProtoLoc->getNumArgs();
2029           OldIdx != NumOldParams; ++OldIdx) {
2030        ParmVarDecl *OldParam = OldProtoLoc->getArg(OldIdx);
2031        if (!OldParam->isParameterPack() ||
2032            (NewIdx < NumNewParams &&
2033             NewProtoLoc->getArg(NewIdx)->isParameterPack())) {
2034          // Simple case: normal parameter, or a parameter pack that's
2035          // instantiated to a (still-dependent) parameter pack.
2036          ParmVarDecl *NewParam = NewProtoLoc->getArg(NewIdx++);
2037          Params.push_back(NewParam);
2038          SemaRef.CurrentInstantiationScope->InstantiatedLocal(OldParam,
2039                                                               NewParam);
2040          continue;
2041        }
2042
2043        // Parameter pack: make the instantiation an argument pack.
2044        SemaRef.CurrentInstantiationScope->MakeInstantiatedLocalArgPack(
2045                                                                      OldParam);
2046        unsigned NumArgumentsInExpansion
2047          = SemaRef.getNumArgumentsInExpansion(OldParam->getType(),
2048                                               TemplateArgs);
2049        while (NumArgumentsInExpansion--) {
2050          ParmVarDecl *NewParam = NewProtoLoc->getArg(NewIdx++);
2051          Params.push_back(NewParam);
2052          SemaRef.CurrentInstantiationScope->InstantiatedLocalPackArg(OldParam,
2053                                                                      NewParam);
2054        }
2055      }
2056    }
2057  } else {
2058    // The function type itself was not dependent and therefore no
2059    // substitution occurred. However, we still need to instantiate
2060    // the function parameters themselves.
2061    TypeLoc OldTL = OldTInfo->getTypeLoc().IgnoreParens();
2062    if (FunctionProtoTypeLoc *OldProtoLoc
2063                                    = dyn_cast<FunctionProtoTypeLoc>(&OldTL)) {
2064      for (unsigned i = 0, i_end = OldProtoLoc->getNumArgs(); i != i_end; ++i) {
2065        ParmVarDecl *Parm = VisitParmVarDecl(OldProtoLoc->getArg(i));
2066        if (!Parm)
2067          return 0;
2068        Params.push_back(Parm);
2069      }
2070    }
2071  }
2072  return NewTInfo;
2073}
2074
2075/// \brief Initializes the common fields of an instantiation function
2076/// declaration (New) from the corresponding fields of its template (Tmpl).
2077///
2078/// \returns true if there was an error
2079bool
2080TemplateDeclInstantiator::InitFunctionInstantiation(FunctionDecl *New,
2081                                                    FunctionDecl *Tmpl) {
2082  if (Tmpl->isDeleted())
2083    New->setDeleted();
2084
2085  // If we are performing substituting explicitly-specified template arguments
2086  // or deduced template arguments into a function template and we reach this
2087  // point, we are now past the point where SFINAE applies and have committed
2088  // to keeping the new function template specialization. We therefore
2089  // convert the active template instantiation for the function template
2090  // into a template instantiation for this specific function template
2091  // specialization, which is not a SFINAE context, so that we diagnose any
2092  // further errors in the declaration itself.
2093  typedef Sema::ActiveTemplateInstantiation ActiveInstType;
2094  ActiveInstType &ActiveInst = SemaRef.ActiveTemplateInstantiations.back();
2095  if (ActiveInst.Kind == ActiveInstType::ExplicitTemplateArgumentSubstitution ||
2096      ActiveInst.Kind == ActiveInstType::DeducedTemplateArgumentSubstitution) {
2097    if (FunctionTemplateDecl *FunTmpl
2098          = dyn_cast<FunctionTemplateDecl>((Decl *)ActiveInst.Entity)) {
2099      assert(FunTmpl->getTemplatedDecl() == Tmpl &&
2100             "Deduction from the wrong function template?");
2101      (void) FunTmpl;
2102      ActiveInst.Kind = ActiveInstType::TemplateInstantiation;
2103      ActiveInst.Entity = reinterpret_cast<uintptr_t>(New);
2104      --SemaRef.NonInstantiationEntries;
2105    }
2106  }
2107
2108  const FunctionProtoType *Proto = Tmpl->getType()->getAs<FunctionProtoType>();
2109  assert(Proto && "Function template without prototype?");
2110
2111  if (Proto->hasExceptionSpec() || Proto->getNoReturnAttr()) {
2112    // The function has an exception specification or a "noreturn"
2113    // attribute. Substitute into each of the exception types.
2114    llvm::SmallVector<QualType, 4> Exceptions;
2115    for (unsigned I = 0, N = Proto->getNumExceptions(); I != N; ++I) {
2116      // FIXME: Poor location information!
2117      if (const PackExpansionType *PackExpansion
2118            = Proto->getExceptionType(I)->getAs<PackExpansionType>()) {
2119        // We have a pack expansion. Instantiate it.
2120        llvm::SmallVector<UnexpandedParameterPack, 2> Unexpanded;
2121        SemaRef.collectUnexpandedParameterPacks(PackExpansion->getPattern(),
2122                                                Unexpanded);
2123        assert(!Unexpanded.empty() &&
2124               "Pack expansion without parameter packs?");
2125
2126        bool Expand = false;
2127        bool RetainExpansion = false;
2128        llvm::Optional<unsigned> NumExpansions
2129                                          = PackExpansion->getNumExpansions();
2130        if (SemaRef.CheckParameterPacksForExpansion(New->getLocation(),
2131                                                    SourceRange(),
2132                                                    Unexpanded.data(),
2133                                                    Unexpanded.size(),
2134                                                    TemplateArgs,
2135                                                    Expand,
2136                                                    RetainExpansion,
2137                                                    NumExpansions))
2138          break;
2139
2140        if (!Expand) {
2141          // We can't expand this pack expansion into separate arguments yet;
2142          // just substitute into the pattern and create a new pack expansion
2143          // type.
2144          Sema::ArgumentPackSubstitutionIndexRAII SubstIndex(SemaRef, -1);
2145          QualType T = SemaRef.SubstType(PackExpansion->getPattern(),
2146                                         TemplateArgs,
2147                                       New->getLocation(), New->getDeclName());
2148          if (T.isNull())
2149            break;
2150
2151          T = SemaRef.Context.getPackExpansionType(T, NumExpansions);
2152          Exceptions.push_back(T);
2153          continue;
2154        }
2155
2156        // Substitute into the pack expansion pattern for each template
2157        bool Invalid = false;
2158        for (unsigned ArgIdx = 0; ArgIdx != *NumExpansions; ++ArgIdx) {
2159          Sema::ArgumentPackSubstitutionIndexRAII SubstIndex(SemaRef, ArgIdx);
2160
2161          QualType T = SemaRef.SubstType(PackExpansion->getPattern(),
2162                                         TemplateArgs,
2163                                       New->getLocation(), New->getDeclName());
2164          if (T.isNull()) {
2165            Invalid = true;
2166            break;
2167          }
2168
2169          Exceptions.push_back(T);
2170        }
2171
2172        if (Invalid)
2173          break;
2174
2175        continue;
2176      }
2177
2178      QualType T
2179        = SemaRef.SubstType(Proto->getExceptionType(I), TemplateArgs,
2180                            New->getLocation(), New->getDeclName());
2181      if (T.isNull() ||
2182          SemaRef.CheckSpecifiedExceptionType(T, New->getLocation()))
2183        continue;
2184
2185      Exceptions.push_back(T);
2186    }
2187    Expr *NoexceptExpr = 0;
2188    if (Expr *OldNoexceptExpr = Proto->getNoexceptExpr()) {
2189      ExprResult E = SemaRef.SubstExpr(OldNoexceptExpr, TemplateArgs);
2190      if (E.isUsable())
2191        NoexceptExpr = E.take();
2192    }
2193
2194    // Rebuild the function type
2195
2196    FunctionProtoType::ExtProtoInfo EPI = Proto->getExtProtoInfo();
2197    EPI.ExceptionSpecType = Proto->getExceptionSpecType();
2198    EPI.NumExceptions = Exceptions.size();
2199    EPI.Exceptions = Exceptions.data();
2200    EPI.NoexceptExpr = NoexceptExpr;
2201    EPI.ExtInfo = Proto->getExtInfo();
2202
2203    const FunctionProtoType *NewProto
2204      = New->getType()->getAs<FunctionProtoType>();
2205    assert(NewProto && "Template instantiation without function prototype?");
2206    New->setType(SemaRef.Context.getFunctionType(NewProto->getResultType(),
2207                                                 NewProto->arg_type_begin(),
2208                                                 NewProto->getNumArgs(),
2209                                                 EPI));
2210  }
2211
2212  SemaRef.InstantiateAttrs(TemplateArgs, Tmpl, New);
2213
2214  return false;
2215}
2216
2217/// \brief Initializes common fields of an instantiated method
2218/// declaration (New) from the corresponding fields of its template
2219/// (Tmpl).
2220///
2221/// \returns true if there was an error
2222bool
2223TemplateDeclInstantiator::InitMethodInstantiation(CXXMethodDecl *New,
2224                                                  CXXMethodDecl *Tmpl) {
2225  if (InitFunctionInstantiation(New, Tmpl))
2226    return true;
2227
2228  New->setAccess(Tmpl->getAccess());
2229  if (Tmpl->isVirtualAsWritten())
2230    New->setVirtualAsWritten(true);
2231
2232  // FIXME: attributes
2233  // FIXME: New needs a pointer to Tmpl
2234  return false;
2235}
2236
2237/// \brief Instantiate the definition of the given function from its
2238/// template.
2239///
2240/// \param PointOfInstantiation the point at which the instantiation was
2241/// required. Note that this is not precisely a "point of instantiation"
2242/// for the function, but it's close.
2243///
2244/// \param Function the already-instantiated declaration of a
2245/// function template specialization or member function of a class template
2246/// specialization.
2247///
2248/// \param Recursive if true, recursively instantiates any functions that
2249/// are required by this instantiation.
2250///
2251/// \param DefinitionRequired if true, then we are performing an explicit
2252/// instantiation where the body of the function is required. Complain if
2253/// there is no such body.
2254void Sema::InstantiateFunctionDefinition(SourceLocation PointOfInstantiation,
2255                                         FunctionDecl *Function,
2256                                         bool Recursive,
2257                                         bool DefinitionRequired) {
2258  if (Function->isInvalidDecl() || Function->hasBody())
2259    return;
2260
2261  // Never instantiate an explicit specialization.
2262  if (Function->getTemplateSpecializationKind() == TSK_ExplicitSpecialization)
2263    return;
2264
2265  // Find the function body that we'll be substituting.
2266  const FunctionDecl *PatternDecl = Function->getTemplateInstantiationPattern();
2267  Stmt *Pattern = 0;
2268  if (PatternDecl)
2269    Pattern = PatternDecl->getBody(PatternDecl);
2270
2271  // Postpone late parsed template instantiations.
2272  if (PatternDecl->isLateTemplateParsed() && !LateTemplateParser) {
2273    PendingInstantiations.push_back(
2274      std::make_pair(Function, PointOfInstantiation));
2275    return;
2276  }
2277
2278  // Call the LateTemplateParser callback if there a need to late parse
2279  // a templated function definition.
2280  if (!Pattern && PatternDecl && PatternDecl->isLateTemplateParsed() &&
2281      LateTemplateParser) {
2282    LateTemplateParser(OpaqueParser, PatternDecl);
2283    Pattern = PatternDecl->getBody(PatternDecl);
2284  }
2285
2286  if (!Pattern) {
2287    if (DefinitionRequired) {
2288      if (Function->getPrimaryTemplate())
2289        Diag(PointOfInstantiation,
2290             diag::err_explicit_instantiation_undefined_func_template)
2291          << Function->getPrimaryTemplate();
2292      else
2293        Diag(PointOfInstantiation,
2294             diag::err_explicit_instantiation_undefined_member)
2295          << 1 << Function->getDeclName() << Function->getDeclContext();
2296
2297      if (PatternDecl)
2298        Diag(PatternDecl->getLocation(),
2299             diag::note_explicit_instantiation_here);
2300      Function->setInvalidDecl();
2301    } else if (Function->getTemplateSpecializationKind()
2302                 == TSK_ExplicitInstantiationDefinition) {
2303      PendingInstantiations.push_back(
2304        std::make_pair(Function, PointOfInstantiation));
2305    }
2306
2307    return;
2308  }
2309
2310  // C++0x [temp.explicit]p9:
2311  //   Except for inline functions, other explicit instantiation declarations
2312  //   have the effect of suppressing the implicit instantiation of the entity
2313  //   to which they refer.
2314  if (Function->getTemplateSpecializationKind()
2315        == TSK_ExplicitInstantiationDeclaration &&
2316      !PatternDecl->isInlined())
2317    return;
2318
2319  InstantiatingTemplate Inst(*this, PointOfInstantiation, Function);
2320  if (Inst)
2321    return;
2322
2323  // If we're performing recursive template instantiation, create our own
2324  // queue of pending implicit instantiations that we will instantiate later,
2325  // while we're still within our own instantiation context.
2326  llvm::SmallVector<VTableUse, 16> SavedVTableUses;
2327  std::deque<PendingImplicitInstantiation> SavedPendingInstantiations;
2328  if (Recursive) {
2329    VTableUses.swap(SavedVTableUses);
2330    PendingInstantiations.swap(SavedPendingInstantiations);
2331  }
2332
2333  EnterExpressionEvaluationContext EvalContext(*this,
2334                                               Sema::PotentiallyEvaluated);
2335  ActOnStartOfFunctionDef(0, Function);
2336
2337  // Introduce a new scope where local variable instantiations will be
2338  // recorded, unless we're actually a member function within a local
2339  // class, in which case we need to merge our results with the parent
2340  // scope (of the enclosing function).
2341  bool MergeWithParentScope = false;
2342  if (CXXRecordDecl *Rec = dyn_cast<CXXRecordDecl>(Function->getDeclContext()))
2343    MergeWithParentScope = Rec->isLocalClass();
2344
2345  LocalInstantiationScope Scope(*this, MergeWithParentScope);
2346
2347  // Introduce the instantiated function parameters into the local
2348  // instantiation scope, and set the parameter names to those used
2349  // in the template.
2350  unsigned FParamIdx = 0;
2351  for (unsigned I = 0, N = PatternDecl->getNumParams(); I != N; ++I) {
2352    const ParmVarDecl *PatternParam = PatternDecl->getParamDecl(I);
2353    if (!PatternParam->isParameterPack()) {
2354      // Simple case: not a parameter pack.
2355      assert(FParamIdx < Function->getNumParams());
2356      ParmVarDecl *FunctionParam = Function->getParamDecl(I);
2357      FunctionParam->setDeclName(PatternParam->getDeclName());
2358      Scope.InstantiatedLocal(PatternParam, FunctionParam);
2359      ++FParamIdx;
2360      continue;
2361    }
2362
2363    // Expand the parameter pack.
2364    Scope.MakeInstantiatedLocalArgPack(PatternParam);
2365    for (unsigned NumFParams = Function->getNumParams();
2366         FParamIdx < NumFParams;
2367         ++FParamIdx) {
2368      ParmVarDecl *FunctionParam = Function->getParamDecl(FParamIdx);
2369      FunctionParam->setDeclName(PatternParam->getDeclName());
2370      Scope.InstantiatedLocalPackArg(PatternParam, FunctionParam);
2371    }
2372  }
2373
2374  // Enter the scope of this instantiation. We don't use
2375  // PushDeclContext because we don't have a scope.
2376  Sema::ContextRAII savedContext(*this, Function);
2377
2378  MultiLevelTemplateArgumentList TemplateArgs =
2379    getTemplateInstantiationArgs(Function, 0, false, PatternDecl);
2380
2381  // If this is a constructor, instantiate the member initializers.
2382  if (const CXXConstructorDecl *Ctor =
2383        dyn_cast<CXXConstructorDecl>(PatternDecl)) {
2384    InstantiateMemInitializers(cast<CXXConstructorDecl>(Function), Ctor,
2385                               TemplateArgs);
2386  }
2387
2388  // Instantiate the function body.
2389  StmtResult Body = SubstStmt(Pattern, TemplateArgs);
2390
2391  if (Body.isInvalid())
2392    Function->setInvalidDecl();
2393
2394  ActOnFinishFunctionBody(Function, Body.get(),
2395                          /*IsInstantiation=*/true);
2396
2397  PerformDependentDiagnostics(PatternDecl, TemplateArgs);
2398
2399  savedContext.pop();
2400
2401  DeclGroupRef DG(Function);
2402  Consumer.HandleTopLevelDecl(DG);
2403
2404  // This class may have local implicit instantiations that need to be
2405  // instantiation within this scope.
2406  PerformPendingInstantiations(/*LocalOnly=*/true);
2407  Scope.Exit();
2408
2409  if (Recursive) {
2410    // Define any pending vtables.
2411    DefineUsedVTables();
2412
2413    // Instantiate any pending implicit instantiations found during the
2414    // instantiation of this template.
2415    PerformPendingInstantiations();
2416
2417    // Restore the set of pending vtables.
2418    VTableUses.swap(SavedVTableUses);
2419
2420    // Restore the set of pending implicit instantiations.
2421    PendingInstantiations.swap(SavedPendingInstantiations);
2422  }
2423}
2424
2425/// \brief Instantiate the definition of the given variable from its
2426/// template.
2427///
2428/// \param PointOfInstantiation the point at which the instantiation was
2429/// required. Note that this is not precisely a "point of instantiation"
2430/// for the function, but it's close.
2431///
2432/// \param Var the already-instantiated declaration of a static member
2433/// variable of a class template specialization.
2434///
2435/// \param Recursive if true, recursively instantiates any functions that
2436/// are required by this instantiation.
2437///
2438/// \param DefinitionRequired if true, then we are performing an explicit
2439/// instantiation where an out-of-line definition of the member variable
2440/// is required. Complain if there is no such definition.
2441void Sema::InstantiateStaticDataMemberDefinition(
2442                                          SourceLocation PointOfInstantiation,
2443                                                 VarDecl *Var,
2444                                                 bool Recursive,
2445                                                 bool DefinitionRequired) {
2446  if (Var->isInvalidDecl())
2447    return;
2448
2449  // Find the out-of-line definition of this static data member.
2450  VarDecl *Def = Var->getInstantiatedFromStaticDataMember();
2451  assert(Def && "This data member was not instantiated from a template?");
2452  assert(Def->isStaticDataMember() && "Not a static data member?");
2453  Def = Def->getOutOfLineDefinition();
2454
2455  if (!Def) {
2456    // We did not find an out-of-line definition of this static data member,
2457    // so we won't perform any instantiation. Rather, we rely on the user to
2458    // instantiate this definition (or provide a specialization for it) in
2459    // another translation unit.
2460    if (DefinitionRequired) {
2461      Def = Var->getInstantiatedFromStaticDataMember();
2462      Diag(PointOfInstantiation,
2463           diag::err_explicit_instantiation_undefined_member)
2464        << 2 << Var->getDeclName() << Var->getDeclContext();
2465      Diag(Def->getLocation(), diag::note_explicit_instantiation_here);
2466    } else if (Var->getTemplateSpecializationKind()
2467                 == TSK_ExplicitInstantiationDefinition) {
2468      PendingInstantiations.push_back(
2469        std::make_pair(Var, PointOfInstantiation));
2470    }
2471
2472    return;
2473  }
2474
2475  // Never instantiate an explicit specialization.
2476  if (Var->getTemplateSpecializationKind() == TSK_ExplicitSpecialization)
2477    return;
2478
2479  // C++0x [temp.explicit]p9:
2480  //   Except for inline functions, other explicit instantiation declarations
2481  //   have the effect of suppressing the implicit instantiation of the entity
2482  //   to which they refer.
2483  if (Var->getTemplateSpecializationKind()
2484        == TSK_ExplicitInstantiationDeclaration)
2485    return;
2486
2487  InstantiatingTemplate Inst(*this, PointOfInstantiation, Var);
2488  if (Inst)
2489    return;
2490
2491  // If we're performing recursive template instantiation, create our own
2492  // queue of pending implicit instantiations that we will instantiate later,
2493  // while we're still within our own instantiation context.
2494  std::deque<PendingImplicitInstantiation> SavedPendingInstantiations;
2495  if (Recursive)
2496    PendingInstantiations.swap(SavedPendingInstantiations);
2497
2498  // Enter the scope of this instantiation. We don't use
2499  // PushDeclContext because we don't have a scope.
2500  ContextRAII previousContext(*this, Var->getDeclContext());
2501
2502  VarDecl *OldVar = Var;
2503  Var = cast_or_null<VarDecl>(SubstDecl(Def, Var->getDeclContext(),
2504                                        getTemplateInstantiationArgs(Var)));
2505
2506  previousContext.pop();
2507
2508  if (Var) {
2509    MemberSpecializationInfo *MSInfo = OldVar->getMemberSpecializationInfo();
2510    assert(MSInfo && "Missing member specialization information?");
2511    Var->setTemplateSpecializationKind(MSInfo->getTemplateSpecializationKind(),
2512                                       MSInfo->getPointOfInstantiation());
2513    DeclGroupRef DG(Var);
2514    Consumer.HandleTopLevelDecl(DG);
2515  }
2516
2517  if (Recursive) {
2518    // Instantiate any pending implicit instantiations found during the
2519    // instantiation of this template.
2520    PerformPendingInstantiations();
2521
2522    // Restore the set of pending implicit instantiations.
2523    PendingInstantiations.swap(SavedPendingInstantiations);
2524  }
2525}
2526
2527void
2528Sema::InstantiateMemInitializers(CXXConstructorDecl *New,
2529                                 const CXXConstructorDecl *Tmpl,
2530                           const MultiLevelTemplateArgumentList &TemplateArgs) {
2531
2532  llvm::SmallVector<MemInitTy*, 4> NewInits;
2533  bool AnyErrors = false;
2534
2535  // Instantiate all the initializers.
2536  for (CXXConstructorDecl::init_const_iterator Inits = Tmpl->init_begin(),
2537                                            InitsEnd = Tmpl->init_end();
2538       Inits != InitsEnd; ++Inits) {
2539    CXXCtorInitializer *Init = *Inits;
2540
2541    // Only instantiate written initializers, let Sema re-construct implicit
2542    // ones.
2543    if (!Init->isWritten())
2544      continue;
2545
2546    SourceLocation LParenLoc, RParenLoc;
2547    ASTOwningVector<Expr*> NewArgs(*this);
2548
2549    SourceLocation EllipsisLoc;
2550
2551    if (Init->isPackExpansion()) {
2552      // This is a pack expansion. We should expand it now.
2553      TypeLoc BaseTL = Init->getBaseClassInfo()->getTypeLoc();
2554      llvm::SmallVector<UnexpandedParameterPack, 2> Unexpanded;
2555      collectUnexpandedParameterPacks(BaseTL, Unexpanded);
2556      bool ShouldExpand = false;
2557      bool RetainExpansion = false;
2558      llvm::Optional<unsigned> NumExpansions;
2559      if (CheckParameterPacksForExpansion(Init->getEllipsisLoc(),
2560                                          BaseTL.getSourceRange(),
2561                                          Unexpanded.data(),
2562                                          Unexpanded.size(),
2563                                          TemplateArgs, ShouldExpand,
2564                                          RetainExpansion,
2565                                          NumExpansions)) {
2566        AnyErrors = true;
2567        New->setInvalidDecl();
2568        continue;
2569      }
2570      assert(ShouldExpand && "Partial instantiation of base initializer?");
2571
2572      // Loop over all of the arguments in the argument pack(s),
2573      for (unsigned I = 0; I != *NumExpansions; ++I) {
2574        Sema::ArgumentPackSubstitutionIndexRAII SubstIndex(*this, I);
2575
2576        // Instantiate the initializer.
2577        if (InstantiateInitializer(*this, Init->getInit(), TemplateArgs,
2578                                   LParenLoc, NewArgs, RParenLoc)) {
2579          AnyErrors = true;
2580          break;
2581        }
2582
2583        // Instantiate the base type.
2584        TypeSourceInfo *BaseTInfo = SubstType(Init->getBaseClassInfo(),
2585                                              TemplateArgs,
2586                                              Init->getSourceLocation(),
2587                                              New->getDeclName());
2588        if (!BaseTInfo) {
2589          AnyErrors = true;
2590          break;
2591        }
2592
2593        // Build the initializer.
2594        MemInitResult NewInit = BuildBaseInitializer(BaseTInfo->getType(),
2595                                                     BaseTInfo,
2596                                                     (Expr **)NewArgs.data(),
2597                                                     NewArgs.size(),
2598                                                     Init->getLParenLoc(),
2599                                                     Init->getRParenLoc(),
2600                                                     New->getParent(),
2601                                                     SourceLocation());
2602        if (NewInit.isInvalid()) {
2603          AnyErrors = true;
2604          break;
2605        }
2606
2607        NewInits.push_back(NewInit.get());
2608        NewArgs.clear();
2609      }
2610
2611      continue;
2612    }
2613
2614    // Instantiate the initializer.
2615    if (InstantiateInitializer(*this, Init->getInit(), TemplateArgs,
2616                               LParenLoc, NewArgs, RParenLoc)) {
2617      AnyErrors = true;
2618      continue;
2619    }
2620
2621    MemInitResult NewInit;
2622    if (Init->isBaseInitializer()) {
2623      TypeSourceInfo *BaseTInfo = SubstType(Init->getBaseClassInfo(),
2624                                            TemplateArgs,
2625                                            Init->getSourceLocation(),
2626                                            New->getDeclName());
2627      if (!BaseTInfo) {
2628        AnyErrors = true;
2629        New->setInvalidDecl();
2630        continue;
2631      }
2632
2633      NewInit = BuildBaseInitializer(BaseTInfo->getType(), BaseTInfo,
2634                                     (Expr **)NewArgs.data(),
2635                                     NewArgs.size(),
2636                                     Init->getLParenLoc(),
2637                                     Init->getRParenLoc(),
2638                                     New->getParent(),
2639                                     EllipsisLoc);
2640    } else if (Init->isMemberInitializer()) {
2641      FieldDecl *Member = cast_or_null<FieldDecl>(FindInstantiatedDecl(
2642                                                     Init->getMemberLocation(),
2643                                                     Init->getMember(),
2644                                                     TemplateArgs));
2645      if (!Member) {
2646        AnyErrors = true;
2647        New->setInvalidDecl();
2648        continue;
2649      }
2650
2651      NewInit = BuildMemberInitializer(Member, (Expr **)NewArgs.data(),
2652                                       NewArgs.size(),
2653                                       Init->getSourceLocation(),
2654                                       Init->getLParenLoc(),
2655                                       Init->getRParenLoc());
2656    } else if (Init->isIndirectMemberInitializer()) {
2657      IndirectFieldDecl *IndirectMember =
2658         cast_or_null<IndirectFieldDecl>(FindInstantiatedDecl(
2659                                 Init->getMemberLocation(),
2660                                 Init->getIndirectMember(), TemplateArgs));
2661
2662      if (!IndirectMember) {
2663        AnyErrors = true;
2664        New->setInvalidDecl();
2665        continue;
2666      }
2667
2668      NewInit = BuildMemberInitializer(IndirectMember, (Expr **)NewArgs.data(),
2669                                       NewArgs.size(),
2670                                       Init->getSourceLocation(),
2671                                       Init->getLParenLoc(),
2672                                       Init->getRParenLoc());
2673    }
2674
2675    if (NewInit.isInvalid()) {
2676      AnyErrors = true;
2677      New->setInvalidDecl();
2678    } else {
2679      // FIXME: It would be nice if ASTOwningVector had a release function.
2680      NewArgs.take();
2681
2682      NewInits.push_back((MemInitTy *)NewInit.get());
2683    }
2684  }
2685
2686  // Assign all the initializers to the new constructor.
2687  ActOnMemInitializers(New,
2688                       /*FIXME: ColonLoc */
2689                       SourceLocation(),
2690                       NewInits.data(), NewInits.size(),
2691                       AnyErrors);
2692}
2693
2694// TODO: this could be templated if the various decl types used the
2695// same method name.
2696static bool isInstantiationOf(ClassTemplateDecl *Pattern,
2697                              ClassTemplateDecl *Instance) {
2698  Pattern = Pattern->getCanonicalDecl();
2699
2700  do {
2701    Instance = Instance->getCanonicalDecl();
2702    if (Pattern == Instance) return true;
2703    Instance = Instance->getInstantiatedFromMemberTemplate();
2704  } while (Instance);
2705
2706  return false;
2707}
2708
2709static bool isInstantiationOf(FunctionTemplateDecl *Pattern,
2710                              FunctionTemplateDecl *Instance) {
2711  Pattern = Pattern->getCanonicalDecl();
2712
2713  do {
2714    Instance = Instance->getCanonicalDecl();
2715    if (Pattern == Instance) return true;
2716    Instance = Instance->getInstantiatedFromMemberTemplate();
2717  } while (Instance);
2718
2719  return false;
2720}
2721
2722static bool
2723isInstantiationOf(ClassTemplatePartialSpecializationDecl *Pattern,
2724                  ClassTemplatePartialSpecializationDecl *Instance) {
2725  Pattern
2726    = cast<ClassTemplatePartialSpecializationDecl>(Pattern->getCanonicalDecl());
2727  do {
2728    Instance = cast<ClassTemplatePartialSpecializationDecl>(
2729                                                Instance->getCanonicalDecl());
2730    if (Pattern == Instance)
2731      return true;
2732    Instance = Instance->getInstantiatedFromMember();
2733  } while (Instance);
2734
2735  return false;
2736}
2737
2738static bool isInstantiationOf(CXXRecordDecl *Pattern,
2739                              CXXRecordDecl *Instance) {
2740  Pattern = Pattern->getCanonicalDecl();
2741
2742  do {
2743    Instance = Instance->getCanonicalDecl();
2744    if (Pattern == Instance) return true;
2745    Instance = Instance->getInstantiatedFromMemberClass();
2746  } while (Instance);
2747
2748  return false;
2749}
2750
2751static bool isInstantiationOf(FunctionDecl *Pattern,
2752                              FunctionDecl *Instance) {
2753  Pattern = Pattern->getCanonicalDecl();
2754
2755  do {
2756    Instance = Instance->getCanonicalDecl();
2757    if (Pattern == Instance) return true;
2758    Instance = Instance->getInstantiatedFromMemberFunction();
2759  } while (Instance);
2760
2761  return false;
2762}
2763
2764static bool isInstantiationOf(EnumDecl *Pattern,
2765                              EnumDecl *Instance) {
2766  Pattern = Pattern->getCanonicalDecl();
2767
2768  do {
2769    Instance = Instance->getCanonicalDecl();
2770    if (Pattern == Instance) return true;
2771    Instance = Instance->getInstantiatedFromMemberEnum();
2772  } while (Instance);
2773
2774  return false;
2775}
2776
2777static bool isInstantiationOf(UsingShadowDecl *Pattern,
2778                              UsingShadowDecl *Instance,
2779                              ASTContext &C) {
2780  return C.getInstantiatedFromUsingShadowDecl(Instance) == Pattern;
2781}
2782
2783static bool isInstantiationOf(UsingDecl *Pattern,
2784                              UsingDecl *Instance,
2785                              ASTContext &C) {
2786  return C.getInstantiatedFromUsingDecl(Instance) == Pattern;
2787}
2788
2789static bool isInstantiationOf(UnresolvedUsingValueDecl *Pattern,
2790                              UsingDecl *Instance,
2791                              ASTContext &C) {
2792  return C.getInstantiatedFromUsingDecl(Instance) == Pattern;
2793}
2794
2795static bool isInstantiationOf(UnresolvedUsingTypenameDecl *Pattern,
2796                              UsingDecl *Instance,
2797                              ASTContext &C) {
2798  return C.getInstantiatedFromUsingDecl(Instance) == Pattern;
2799}
2800
2801static bool isInstantiationOfStaticDataMember(VarDecl *Pattern,
2802                                              VarDecl *Instance) {
2803  assert(Instance->isStaticDataMember());
2804
2805  Pattern = Pattern->getCanonicalDecl();
2806
2807  do {
2808    Instance = Instance->getCanonicalDecl();
2809    if (Pattern == Instance) return true;
2810    Instance = Instance->getInstantiatedFromStaticDataMember();
2811  } while (Instance);
2812
2813  return false;
2814}
2815
2816// Other is the prospective instantiation
2817// D is the prospective pattern
2818static bool isInstantiationOf(ASTContext &Ctx, NamedDecl *D, Decl *Other) {
2819  if (D->getKind() != Other->getKind()) {
2820    if (UnresolvedUsingTypenameDecl *UUD
2821          = dyn_cast<UnresolvedUsingTypenameDecl>(D)) {
2822      if (UsingDecl *UD = dyn_cast<UsingDecl>(Other)) {
2823        return isInstantiationOf(UUD, UD, Ctx);
2824      }
2825    }
2826
2827    if (UnresolvedUsingValueDecl *UUD
2828          = dyn_cast<UnresolvedUsingValueDecl>(D)) {
2829      if (UsingDecl *UD = dyn_cast<UsingDecl>(Other)) {
2830        return isInstantiationOf(UUD, UD, Ctx);
2831      }
2832    }
2833
2834    return false;
2835  }
2836
2837  if (CXXRecordDecl *Record = dyn_cast<CXXRecordDecl>(Other))
2838    return isInstantiationOf(cast<CXXRecordDecl>(D), Record);
2839
2840  if (FunctionDecl *Function = dyn_cast<FunctionDecl>(Other))
2841    return isInstantiationOf(cast<FunctionDecl>(D), Function);
2842
2843  if (EnumDecl *Enum = dyn_cast<EnumDecl>(Other))
2844    return isInstantiationOf(cast<EnumDecl>(D), Enum);
2845
2846  if (VarDecl *Var = dyn_cast<VarDecl>(Other))
2847    if (Var->isStaticDataMember())
2848      return isInstantiationOfStaticDataMember(cast<VarDecl>(D), Var);
2849
2850  if (ClassTemplateDecl *Temp = dyn_cast<ClassTemplateDecl>(Other))
2851    return isInstantiationOf(cast<ClassTemplateDecl>(D), Temp);
2852
2853  if (FunctionTemplateDecl *Temp = dyn_cast<FunctionTemplateDecl>(Other))
2854    return isInstantiationOf(cast<FunctionTemplateDecl>(D), Temp);
2855
2856  if (ClassTemplatePartialSpecializationDecl *PartialSpec
2857        = dyn_cast<ClassTemplatePartialSpecializationDecl>(Other))
2858    return isInstantiationOf(cast<ClassTemplatePartialSpecializationDecl>(D),
2859                             PartialSpec);
2860
2861  if (FieldDecl *Field = dyn_cast<FieldDecl>(Other)) {
2862    if (!Field->getDeclName()) {
2863      // This is an unnamed field.
2864      return Ctx.getInstantiatedFromUnnamedFieldDecl(Field) ==
2865        cast<FieldDecl>(D);
2866    }
2867  }
2868
2869  if (UsingDecl *Using = dyn_cast<UsingDecl>(Other))
2870    return isInstantiationOf(cast<UsingDecl>(D), Using, Ctx);
2871
2872  if (UsingShadowDecl *Shadow = dyn_cast<UsingShadowDecl>(Other))
2873    return isInstantiationOf(cast<UsingShadowDecl>(D), Shadow, Ctx);
2874
2875  return D->getDeclName() && isa<NamedDecl>(Other) &&
2876    D->getDeclName() == cast<NamedDecl>(Other)->getDeclName();
2877}
2878
2879template<typename ForwardIterator>
2880static NamedDecl *findInstantiationOf(ASTContext &Ctx,
2881                                      NamedDecl *D,
2882                                      ForwardIterator first,
2883                                      ForwardIterator last) {
2884  for (; first != last; ++first)
2885    if (isInstantiationOf(Ctx, D, *first))
2886      return cast<NamedDecl>(*first);
2887
2888  return 0;
2889}
2890
2891/// \brief Finds the instantiation of the given declaration context
2892/// within the current instantiation.
2893///
2894/// \returns NULL if there was an error
2895DeclContext *Sema::FindInstantiatedContext(SourceLocation Loc, DeclContext* DC,
2896                          const MultiLevelTemplateArgumentList &TemplateArgs) {
2897  if (NamedDecl *D = dyn_cast<NamedDecl>(DC)) {
2898    Decl* ID = FindInstantiatedDecl(Loc, D, TemplateArgs);
2899    return cast_or_null<DeclContext>(ID);
2900  } else return DC;
2901}
2902
2903/// \brief Find the instantiation of the given declaration within the
2904/// current instantiation.
2905///
2906/// This routine is intended to be used when \p D is a declaration
2907/// referenced from within a template, that needs to mapped into the
2908/// corresponding declaration within an instantiation. For example,
2909/// given:
2910///
2911/// \code
2912/// template<typename T>
2913/// struct X {
2914///   enum Kind {
2915///     KnownValue = sizeof(T)
2916///   };
2917///
2918///   bool getKind() const { return KnownValue; }
2919/// };
2920///
2921/// template struct X<int>;
2922/// \endcode
2923///
2924/// In the instantiation of X<int>::getKind(), we need to map the
2925/// EnumConstantDecl for KnownValue (which refers to
2926/// X<T>::<Kind>::KnownValue) to its instantiation
2927/// (X<int>::<Kind>::KnownValue). InstantiateCurrentDeclRef() performs
2928/// this mapping from within the instantiation of X<int>.
2929NamedDecl *Sema::FindInstantiatedDecl(SourceLocation Loc, NamedDecl *D,
2930                          const MultiLevelTemplateArgumentList &TemplateArgs) {
2931  DeclContext *ParentDC = D->getDeclContext();
2932  if (isa<ParmVarDecl>(D) || isa<NonTypeTemplateParmDecl>(D) ||
2933      isa<TemplateTypeParmDecl>(D) || isa<TemplateTemplateParmDecl>(D) ||
2934      (ParentDC->isFunctionOrMethod() && ParentDC->isDependentContext())) {
2935    // D is a local of some kind. Look into the map of local
2936    // declarations to their instantiations.
2937    typedef LocalInstantiationScope::DeclArgumentPack DeclArgumentPack;
2938    llvm::PointerUnion<Decl *, DeclArgumentPack *> *Found
2939      = CurrentInstantiationScope->findInstantiationOf(D);
2940
2941    if (Found) {
2942      if (Decl *FD = Found->dyn_cast<Decl *>())
2943        return cast<NamedDecl>(FD);
2944
2945      unsigned PackIdx = ArgumentPackSubstitutionIndex;
2946      return cast<NamedDecl>((*Found->get<DeclArgumentPack *>())[PackIdx]);
2947    }
2948
2949    // If we didn't find the decl, then we must have a label decl that hasn't
2950    // been found yet.  Lazily instantiate it and return it now.
2951    assert(isa<LabelDecl>(D));
2952
2953    Decl *Inst = SubstDecl(D, CurContext, TemplateArgs);
2954    assert(Inst && "Failed to instantiate label??");
2955
2956    CurrentInstantiationScope->InstantiatedLocal(D, Inst);
2957    return cast<LabelDecl>(Inst);
2958  }
2959
2960  if (CXXRecordDecl *Record = dyn_cast<CXXRecordDecl>(D)) {
2961    if (!Record->isDependentContext())
2962      return D;
2963
2964    // If the RecordDecl is actually the injected-class-name or a
2965    // "templated" declaration for a class template, class template
2966    // partial specialization, or a member class of a class template,
2967    // substitute into the injected-class-name of the class template
2968    // or partial specialization to find the new DeclContext.
2969    QualType T;
2970    ClassTemplateDecl *ClassTemplate = Record->getDescribedClassTemplate();
2971
2972    if (ClassTemplate) {
2973      T = ClassTemplate->getInjectedClassNameSpecialization();
2974    } else if (ClassTemplatePartialSpecializationDecl *PartialSpec
2975                 = dyn_cast<ClassTemplatePartialSpecializationDecl>(Record)) {
2976      ClassTemplate = PartialSpec->getSpecializedTemplate();
2977
2978      // If we call SubstType with an InjectedClassNameType here we
2979      // can end up in an infinite loop.
2980      T = Context.getTypeDeclType(Record);
2981      assert(isa<InjectedClassNameType>(T) &&
2982             "type of partial specialization is not an InjectedClassNameType");
2983      T = cast<InjectedClassNameType>(T)->getInjectedSpecializationType();
2984    }
2985
2986    if (!T.isNull()) {
2987      // Substitute into the injected-class-name to get the type
2988      // corresponding to the instantiation we want, which may also be
2989      // the current instantiation (if we're in a template
2990      // definition). This substitution should never fail, since we
2991      // know we can instantiate the injected-class-name or we
2992      // wouldn't have gotten to the injected-class-name!
2993
2994      // FIXME: Can we use the CurrentInstantiationScope to avoid this
2995      // extra instantiation in the common case?
2996      T = SubstType(T, TemplateArgs, Loc, DeclarationName());
2997      assert(!T.isNull() && "Instantiation of injected-class-name cannot fail.");
2998
2999      if (!T->isDependentType()) {
3000        assert(T->isRecordType() && "Instantiation must produce a record type");
3001        return T->getAs<RecordType>()->getDecl();
3002      }
3003
3004      // We are performing "partial" template instantiation to create
3005      // the member declarations for the members of a class template
3006      // specialization. Therefore, D is actually referring to something
3007      // in the current instantiation. Look through the current
3008      // context, which contains actual instantiations, to find the
3009      // instantiation of the "current instantiation" that D refers
3010      // to.
3011      bool SawNonDependentContext = false;
3012      for (DeclContext *DC = CurContext; !DC->isFileContext();
3013           DC = DC->getParent()) {
3014        if (ClassTemplateSpecializationDecl *Spec
3015                          = dyn_cast<ClassTemplateSpecializationDecl>(DC))
3016          if (isInstantiationOf(ClassTemplate,
3017                                Spec->getSpecializedTemplate()))
3018            return Spec;
3019
3020        if (!DC->isDependentContext())
3021          SawNonDependentContext = true;
3022      }
3023
3024      // We're performing "instantiation" of a member of the current
3025      // instantiation while we are type-checking the
3026      // definition. Compute the declaration context and return that.
3027      assert(!SawNonDependentContext &&
3028             "No dependent context while instantiating record");
3029      DeclContext *DC = computeDeclContext(T);
3030      assert(DC &&
3031             "Unable to find declaration for the current instantiation");
3032      return cast<CXXRecordDecl>(DC);
3033    }
3034
3035    // Fall through to deal with other dependent record types (e.g.,
3036    // anonymous unions in class templates).
3037  }
3038
3039  if (!ParentDC->isDependentContext())
3040    return D;
3041
3042  ParentDC = FindInstantiatedContext(Loc, ParentDC, TemplateArgs);
3043  if (!ParentDC)
3044    return 0;
3045
3046  if (ParentDC != D->getDeclContext()) {
3047    // We performed some kind of instantiation in the parent context,
3048    // so now we need to look into the instantiated parent context to
3049    // find the instantiation of the declaration D.
3050
3051    // If our context used to be dependent, we may need to instantiate
3052    // it before performing lookup into that context.
3053    bool IsBeingInstantiated = false;
3054    if (CXXRecordDecl *Spec = dyn_cast<CXXRecordDecl>(ParentDC)) {
3055      if (!Spec->isDependentContext()) {
3056        QualType T = Context.getTypeDeclType(Spec);
3057        const RecordType *Tag = T->getAs<RecordType>();
3058        assert(Tag && "type of non-dependent record is not a RecordType");
3059        if (Tag->isBeingDefined())
3060          IsBeingInstantiated = true;
3061        if (!Tag->isBeingDefined() &&
3062            RequireCompleteType(Loc, T, diag::err_incomplete_type))
3063          return 0;
3064
3065        ParentDC = Tag->getDecl();
3066      }
3067    }
3068
3069    NamedDecl *Result = 0;
3070    if (D->getDeclName()) {
3071      DeclContext::lookup_result Found = ParentDC->lookup(D->getDeclName());
3072      Result = findInstantiationOf(Context, D, Found.first, Found.second);
3073    } else {
3074      // Since we don't have a name for the entity we're looking for,
3075      // our only option is to walk through all of the declarations to
3076      // find that name. This will occur in a few cases:
3077      //
3078      //   - anonymous struct/union within a template
3079      //   - unnamed class/struct/union/enum within a template
3080      //
3081      // FIXME: Find a better way to find these instantiations!
3082      Result = findInstantiationOf(Context, D,
3083                                   ParentDC->decls_begin(),
3084                                   ParentDC->decls_end());
3085    }
3086
3087    if (!Result) {
3088      if (isa<UsingShadowDecl>(D)) {
3089        // UsingShadowDecls can instantiate to nothing because of using hiding.
3090      } else if (Diags.hasErrorOccurred()) {
3091        // We've already complained about something, so most likely this
3092        // declaration failed to instantiate. There's no point in complaining
3093        // further, since this is normal in invalid code.
3094      } else if (IsBeingInstantiated) {
3095        // The class in which this member exists is currently being
3096        // instantiated, and we haven't gotten around to instantiating this
3097        // member yet. This can happen when the code uses forward declarations
3098        // of member classes, and introduces ordering dependencies via
3099        // template instantiation.
3100        Diag(Loc, diag::err_member_not_yet_instantiated)
3101          << D->getDeclName()
3102          << Context.getTypeDeclType(cast<CXXRecordDecl>(ParentDC));
3103        Diag(D->getLocation(), diag::note_non_instantiated_member_here);
3104      } else {
3105        // We should have found something, but didn't.
3106        llvm_unreachable("Unable to find instantiation of declaration!");
3107      }
3108    }
3109
3110    D = Result;
3111  }
3112
3113  return D;
3114}
3115
3116/// \brief Performs template instantiation for all implicit template
3117/// instantiations we have seen until this point.
3118///
3119/// \returns true if anything was instantiated.
3120bool Sema::PerformPendingInstantiations(bool LocalOnly) {
3121  bool InstantiatedAnything = false;
3122  while (!PendingLocalImplicitInstantiations.empty() ||
3123         (!LocalOnly && !PendingInstantiations.empty())) {
3124    PendingImplicitInstantiation Inst;
3125
3126    if (PendingLocalImplicitInstantiations.empty()) {
3127      Inst = PendingInstantiations.front();
3128      PendingInstantiations.pop_front();
3129    } else {
3130      Inst = PendingLocalImplicitInstantiations.front();
3131      PendingLocalImplicitInstantiations.pop_front();
3132    }
3133
3134    // Instantiate function definitions
3135    if (FunctionDecl *Function = dyn_cast<FunctionDecl>(Inst.first)) {
3136      PrettyDeclStackTraceEntry CrashInfo(*this, Function, SourceLocation(),
3137                                          "instantiating function definition");
3138      bool DefinitionRequired = Function->getTemplateSpecializationKind() ==
3139                                TSK_ExplicitInstantiationDefinition;
3140      InstantiateFunctionDefinition(/*FIXME:*/Inst.second, Function, true,
3141                                    DefinitionRequired);
3142      InstantiatedAnything = true;
3143      continue;
3144    }
3145
3146    // Instantiate static data member definitions.
3147    VarDecl *Var = cast<VarDecl>(Inst.first);
3148    assert(Var->isStaticDataMember() && "Not a static data member?");
3149
3150    // Don't try to instantiate declarations if the most recent redeclaration
3151    // is invalid.
3152    if (Var->getMostRecentDeclaration()->isInvalidDecl())
3153      continue;
3154
3155    // Check if the most recent declaration has changed the specialization kind
3156    // and removed the need for implicit instantiation.
3157    switch (Var->getMostRecentDeclaration()->getTemplateSpecializationKind()) {
3158    case TSK_Undeclared:
3159      assert(false && "Cannot instantitiate an undeclared specialization.");
3160    case TSK_ExplicitInstantiationDeclaration:
3161    case TSK_ExplicitSpecialization:
3162      continue;  // No longer need to instantiate this type.
3163    case TSK_ExplicitInstantiationDefinition:
3164      // We only need an instantiation if the pending instantiation *is* the
3165      // explicit instantiation.
3166      if (Var != Var->getMostRecentDeclaration()) continue;
3167    case TSK_ImplicitInstantiation:
3168      break;
3169    }
3170
3171    PrettyDeclStackTraceEntry CrashInfo(*this, Var, Var->getLocation(),
3172                                        "instantiating static data member "
3173                                        "definition");
3174
3175    bool DefinitionRequired = Var->getTemplateSpecializationKind() ==
3176                              TSK_ExplicitInstantiationDefinition;
3177    InstantiateStaticDataMemberDefinition(/*FIXME:*/Inst.second, Var, true,
3178                                          DefinitionRequired);
3179    InstantiatedAnything = true;
3180  }
3181
3182  return InstantiatedAnything;
3183}
3184
3185void Sema::PerformDependentDiagnostics(const DeclContext *Pattern,
3186                       const MultiLevelTemplateArgumentList &TemplateArgs) {
3187  for (DeclContext::ddiag_iterator I = Pattern->ddiag_begin(),
3188         E = Pattern->ddiag_end(); I != E; ++I) {
3189    DependentDiagnostic *DD = *I;
3190
3191    switch (DD->getKind()) {
3192    case DependentDiagnostic::Access:
3193      HandleDependentAccessCheck(*DD, TemplateArgs);
3194      break;
3195    }
3196  }
3197}
3198