SemaTemplateInstantiateDecl.cpp revision 53e535161dfa9850de394b300915fc250eb0fdf4 
1//===--- SemaTemplateInstantiateDecl.cpp - C++ Template Decl Instantiation ===/
2//
3//                     The LLVM Compiler Infrastructure
4//
5// This file is distributed under the University of Illinois Open Source
6// License. See LICENSE.TXT for details.
7//===----------------------------------------------------------------------===/
8//
9//  This file implements C++ template instantiation for declarations.
10//
11//===----------------------------------------------------------------------===/
12#include "clang/Sema/SemaInternal.h"
13#include "clang/Sema/Lookup.h"
14#include "clang/Sema/PrettyDeclStackTrace.h"
15#include "clang/Sema/Template.h"
16#include "clang/AST/ASTConsumer.h"
17#include "clang/AST/ASTContext.h"
18#include "clang/AST/DeclTemplate.h"
19#include "clang/AST/DeclVisitor.h"
20#include "clang/AST/DependentDiagnostic.h"
21#include "clang/AST/Expr.h"
22#include "clang/AST/ExprCXX.h"
23#include "clang/AST/TypeLoc.h"
24#include "clang/Lex/Preprocessor.h"
25
26using namespace clang;
27
28bool TemplateDeclInstantiator::SubstQualifier(const DeclaratorDecl *OldDecl,
29                                              DeclaratorDecl *NewDecl) {
30  if (!OldDecl->getQualifierLoc())
31    return false;
32
33  NestedNameSpecifierLoc NewQualifierLoc
34    = SemaRef.SubstNestedNameSpecifierLoc(OldDecl->getQualifierLoc(),
35                                          TemplateArgs);
36
37  if (!NewQualifierLoc)
38    return true;
39
40  NewDecl->setQualifierInfo(NewQualifierLoc);
41  return false;
42}
43
44bool TemplateDeclInstantiator::SubstQualifier(const TagDecl *OldDecl,
45                                              TagDecl *NewDecl) {
46  if (!OldDecl->getQualifierLoc())
47    return false;
48
49  NestedNameSpecifierLoc NewQualifierLoc
50  = SemaRef.SubstNestedNameSpecifierLoc(OldDecl->getQualifierLoc(),
51                                        TemplateArgs);
52
53  if (!NewQualifierLoc)
54    return true;
55
56  NewDecl->setQualifierInfo(NewQualifierLoc);
57  return false;
58}
59
60// FIXME: Is this still too simple?
61void Sema::InstantiateAttrs(const MultiLevelTemplateArgumentList &TemplateArgs,
62                            const Decl *Tmpl, Decl *New) {
63  for (AttrVec::const_iterator i = Tmpl->attr_begin(), e = Tmpl->attr_end();
64       i != e; ++i) {
65    const Attr *TmplAttr = *i;
66    // FIXME: This should be generalized to more than just the AlignedAttr.
67    if (const AlignedAttr *Aligned = dyn_cast<AlignedAttr>(TmplAttr)) {
68      if (Aligned->isAlignmentDependent()) {
69        // The alignment expression is not potentially evaluated.
70        EnterExpressionEvaluationContext Unevaluated(*this,
71                                                     Sema::Unevaluated);
72
73        if (Aligned->isAlignmentExpr()) {
74          ExprResult Result = SubstExpr(Aligned->getAlignmentExpr(),
75                                        TemplateArgs);
76          if (!Result.isInvalid())
77            AddAlignedAttr(Aligned->getLocation(), New, Result.takeAs<Expr>());
78        }
79        else {
80          TypeSourceInfo *Result = SubstType(Aligned->getAlignmentType(),
81                                             TemplateArgs,
82                                             Aligned->getLocation(),
83                                             DeclarationName());
84          if (Result)
85            AddAlignedAttr(Aligned->getLocation(), New, Result);
86        }
87        continue;
88      }
89    }
90
91    // FIXME: Is cloning correct for all attributes?
92    Attr *NewAttr = TmplAttr->clone(Context);
93    New->addAttr(NewAttr);
94  }
95}
96
97Decl *
98TemplateDeclInstantiator::VisitTranslationUnitDecl(TranslationUnitDecl *D) {
99  llvm_unreachable("Translation units cannot be instantiated");
100}
101
102Decl *
103TemplateDeclInstantiator::VisitLabelDecl(LabelDecl *D) {
104  LabelDecl *Inst = LabelDecl::Create(SemaRef.Context, Owner, D->getLocation(),
105                                      D->getIdentifier());
106  Owner->addDecl(Inst);
107  return Inst;
108}
109
110Decl *
111TemplateDeclInstantiator::VisitNamespaceDecl(NamespaceDecl *D) {
112  llvm_unreachable("Namespaces cannot be instantiated");
113}
114
115Decl *
116TemplateDeclInstantiator::VisitNamespaceAliasDecl(NamespaceAliasDecl *D) {
117  NamespaceAliasDecl *Inst
118    = NamespaceAliasDecl::Create(SemaRef.Context, Owner,
119                                 D->getNamespaceLoc(),
120                                 D->getAliasLoc(),
121                                 D->getIdentifier(),
122                                 D->getQualifierLoc(),
123                                 D->getTargetNameLoc(),
124                                 D->getNamespace());
125  Owner->addDecl(Inst);
126  return Inst;
127}
128
129Decl *TemplateDeclInstantiator::InstantiateTypedefNameDecl(TypedefNameDecl *D,
130                                                           bool IsTypeAlias) {
131  bool Invalid = false;
132  TypeSourceInfo *DI = D->getTypeSourceInfo();
133  if (DI->getType()->isInstantiationDependentType() ||
134      DI->getType()->isVariablyModifiedType()) {
135    DI = SemaRef.SubstType(DI, TemplateArgs,
136                           D->getLocation(), D->getDeclName());
137    if (!DI) {
138      Invalid = true;
139      DI = SemaRef.Context.getTrivialTypeSourceInfo(SemaRef.Context.IntTy);
140    }
141  } else {
142    SemaRef.MarkDeclarationsReferencedInType(D->getLocation(), DI->getType());
143  }
144
145  // Create the new typedef
146  TypedefNameDecl *Typedef;
147  if (IsTypeAlias)
148    Typedef = TypeAliasDecl::Create(SemaRef.Context, Owner, D->getLocStart(),
149                                    D->getLocation(), D->getIdentifier(), DI);
150  else
151    Typedef = TypedefDecl::Create(SemaRef.Context, Owner, D->getLocStart(),
152                                  D->getLocation(), D->getIdentifier(), DI);
153  if (Invalid)
154    Typedef->setInvalidDecl();
155
156  // If the old typedef was the name for linkage purposes of an anonymous
157  // tag decl, re-establish that relationship for the new typedef.
158  if (const TagType *oldTagType = D->getUnderlyingType()->getAs<TagType>()) {
159    TagDecl *oldTag = oldTagType->getDecl();
160    if (oldTag->getTypedefNameForAnonDecl() == D) {
161      TagDecl *newTag = DI->getType()->castAs<TagType>()->getDecl();
162      assert(!newTag->getIdentifier() && !newTag->getTypedefNameForAnonDecl());
163      newTag->setTypedefNameForAnonDecl(Typedef);
164    }
165  }
166
167  if (TypedefNameDecl *Prev = D->getPreviousDeclaration()) {
168    NamedDecl *InstPrev = SemaRef.FindInstantiatedDecl(D->getLocation(), Prev,
169                                                       TemplateArgs);
170    if (!InstPrev)
171      return 0;
172
173    Typedef->setPreviousDeclaration(cast<TypedefNameDecl>(InstPrev));
174  }
175
176  SemaRef.InstantiateAttrs(TemplateArgs, D, Typedef);
177
178  Typedef->setAccess(D->getAccess());
179
180  return Typedef;
181}
182
183Decl *TemplateDeclInstantiator::VisitTypedefDecl(TypedefDecl *D) {
184  Decl *Typedef = InstantiateTypedefNameDecl(D, /*IsTypeAlias=*/false);
185  Owner->addDecl(Typedef);
186  return Typedef;
187}
188
189Decl *TemplateDeclInstantiator::VisitTypeAliasDecl(TypeAliasDecl *D) {
190  Decl *Typedef = InstantiateTypedefNameDecl(D, /*IsTypeAlias=*/true);
191  Owner->addDecl(Typedef);
192  return Typedef;
193}
194
195Decl *
196TemplateDeclInstantiator::VisitTypeAliasTemplateDecl(TypeAliasTemplateDecl *D) {
197  // Create a local instantiation scope for this type alias template, which
198  // will contain the instantiations of the template parameters.
199  LocalInstantiationScope Scope(SemaRef);
200
201  TemplateParameterList *TempParams = D->getTemplateParameters();
202  TemplateParameterList *InstParams = SubstTemplateParams(TempParams);
203  if (!InstParams)
204    return 0;
205
206  TypeAliasDecl *Pattern = D->getTemplatedDecl();
207
208  TypeAliasTemplateDecl *PrevAliasTemplate = 0;
209  if (Pattern->getPreviousDeclaration()) {
210    DeclContext::lookup_result Found = Owner->lookup(Pattern->getDeclName());
211    if (Found.first != Found.second) {
212      PrevAliasTemplate = dyn_cast<TypeAliasTemplateDecl>(*Found.first);
213    }
214  }
215
216  TypeAliasDecl *AliasInst = cast_or_null<TypeAliasDecl>(
217    InstantiateTypedefNameDecl(Pattern, /*IsTypeAlias=*/true));
218  if (!AliasInst)
219    return 0;
220
221  TypeAliasTemplateDecl *Inst
222    = TypeAliasTemplateDecl::Create(SemaRef.Context, Owner, D->getLocation(),
223                                    D->getDeclName(), InstParams, AliasInst);
224  if (PrevAliasTemplate)
225    Inst->setPreviousDeclaration(PrevAliasTemplate);
226
227  Inst->setAccess(D->getAccess());
228
229  if (!PrevAliasTemplate)
230    Inst->setInstantiatedFromMemberTemplate(D);
231
232  Owner->addDecl(Inst);
233
234  return Inst;
235}
236
237/// \brief Instantiate an initializer, breaking it into separate
238/// initialization arguments.
239///
240/// \param Init The initializer to instantiate.
241///
242/// \param TemplateArgs Template arguments to be substituted into the
243/// initializer.
244///
245/// \param NewArgs Will be filled in with the instantiation arguments.
246///
247/// \returns true if an error occurred, false otherwise
248bool Sema::InstantiateInitializer(Expr *Init,
249                            const MultiLevelTemplateArgumentList &TemplateArgs,
250                                  SourceLocation &LParenLoc,
251                                  ASTOwningVector<Expr*> &NewArgs,
252                                  SourceLocation &RParenLoc) {
253  NewArgs.clear();
254  LParenLoc = SourceLocation();
255  RParenLoc = SourceLocation();
256
257  if (!Init)
258    return false;
259
260  if (ExprWithCleanups *ExprTemp = dyn_cast<ExprWithCleanups>(Init))
261    Init = ExprTemp->getSubExpr();
262
263  while (CXXBindTemporaryExpr *Binder = dyn_cast<CXXBindTemporaryExpr>(Init))
264    Init = Binder->getSubExpr();
265
266  if (ImplicitCastExpr *ICE = dyn_cast<ImplicitCastExpr>(Init))
267    Init = ICE->getSubExprAsWritten();
268
269  if (ParenListExpr *ParenList = dyn_cast<ParenListExpr>(Init)) {
270    LParenLoc = ParenList->getLParenLoc();
271    RParenLoc = ParenList->getRParenLoc();
272    return SubstExprs(ParenList->getExprs(), ParenList->getNumExprs(),
273                      true, TemplateArgs, NewArgs);
274  }
275
276  if (CXXConstructExpr *Construct = dyn_cast<CXXConstructExpr>(Init)) {
277    if (!isa<CXXTemporaryObjectExpr>(Construct)) {
278      if (SubstExprs(Construct->getArgs(), Construct->getNumArgs(), true,
279                     TemplateArgs, NewArgs))
280        return true;
281
282      // FIXME: Fake locations!
283      LParenLoc = PP.getLocForEndOfToken(Init->getLocStart());
284      RParenLoc = LParenLoc;
285      return false;
286    }
287  }
288
289  ExprResult Result = SubstExpr(Init, TemplateArgs);
290  if (Result.isInvalid())
291    return true;
292
293  NewArgs.push_back(Result.takeAs<Expr>());
294  return false;
295}
296
297Decl *TemplateDeclInstantiator::VisitVarDecl(VarDecl *D) {
298  // If this is the variable for an anonymous struct or union,
299  // instantiate the anonymous struct/union type first.
300  if (const RecordType *RecordTy = D->getType()->getAs<RecordType>())
301    if (RecordTy->getDecl()->isAnonymousStructOrUnion())
302      if (!VisitCXXRecordDecl(cast<CXXRecordDecl>(RecordTy->getDecl())))
303        return 0;
304
305  // Do substitution on the type of the declaration
306  TypeSourceInfo *DI = SemaRef.SubstType(D->getTypeSourceInfo(),
307                                         TemplateArgs,
308                                         D->getTypeSpecStartLoc(),
309                                         D->getDeclName());
310  if (!DI)
311    return 0;
312
313  if (DI->getType()->isFunctionType()) {
314    SemaRef.Diag(D->getLocation(), diag::err_variable_instantiates_to_function)
315      << D->isStaticDataMember() << DI->getType();
316    return 0;
317  }
318
319  // Build the instantiated declaration
320  VarDecl *Var = VarDecl::Create(SemaRef.Context, Owner,
321                                 D->getInnerLocStart(),
322                                 D->getLocation(), D->getIdentifier(),
323                                 DI->getType(), DI,
324                                 D->getStorageClass(),
325                                 D->getStorageClassAsWritten());
326  Var->setThreadSpecified(D->isThreadSpecified());
327  Var->setCXXDirectInitializer(D->hasCXXDirectInitializer());
328  Var->setCXXForRangeDecl(D->isCXXForRangeDecl());
329
330  // Substitute the nested name specifier, if any.
331  if (SubstQualifier(D, Var))
332    return 0;
333
334  // If we are instantiating a static data member defined
335  // out-of-line, the instantiation will have the same lexical
336  // context (which will be a namespace scope) as the template.
337  if (D->isOutOfLine())
338    Var->setLexicalDeclContext(D->getLexicalDeclContext());
339
340  Var->setAccess(D->getAccess());
341
342  if (!D->isStaticDataMember()) {
343    Var->setUsed(D->isUsed(false));
344    Var->setReferenced(D->isReferenced());
345  }
346
347  // FIXME: In theory, we could have a previous declaration for variables that
348  // are not static data members.
349  // FIXME: having to fake up a LookupResult is dumb.
350  LookupResult Previous(SemaRef, Var->getDeclName(), Var->getLocation(),
351                        Sema::LookupOrdinaryName, Sema::ForRedeclaration);
352  if (D->isStaticDataMember())
353    SemaRef.LookupQualifiedName(Previous, Owner, false);
354  SemaRef.CheckVariableDeclaration(Var, Previous);
355
356  if (D->isOutOfLine()) {
357    if (!D->isStaticDataMember())
358      D->getLexicalDeclContext()->addDecl(Var);
359    Owner->makeDeclVisibleInContext(Var);
360  } else {
361    Owner->addDecl(Var);
362    if (Owner->isFunctionOrMethod())
363      SemaRef.CurrentInstantiationScope->InstantiatedLocal(D, Var);
364  }
365  SemaRef.InstantiateAttrs(TemplateArgs, D, Var);
366
367  // Link instantiations of static data members back to the template from
368  // which they were instantiated.
369  if (Var->isStaticDataMember())
370    SemaRef.Context.setInstantiatedFromStaticDataMember(Var, D,
371                                                     TSK_ImplicitInstantiation);
372
373  if (Var->getAnyInitializer()) {
374    // We already have an initializer in the class.
375  } else if (D->getInit()) {
376    if (Var->isStaticDataMember() && !D->isOutOfLine())
377      SemaRef.PushExpressionEvaluationContext(Sema::Unevaluated);
378    else
379      SemaRef.PushExpressionEvaluationContext(Sema::PotentiallyEvaluated);
380
381    // Instantiate the initializer.
382    SourceLocation LParenLoc, RParenLoc;
383    ASTOwningVector<Expr*> InitArgs(SemaRef);
384    if (!SemaRef.InstantiateInitializer(D->getInit(), TemplateArgs, LParenLoc,
385                                        InitArgs, RParenLoc)) {
386      bool TypeMayContainAuto = true;
387      // Attach the initializer to the declaration, if we have one.
388      if (InitArgs.size() == 0)
389        SemaRef.ActOnUninitializedDecl(Var, TypeMayContainAuto);
390      else if (D->hasCXXDirectInitializer()) {
391        // Add the direct initializer to the declaration.
392        SemaRef.AddCXXDirectInitializerToDecl(Var,
393                                              LParenLoc,
394                                              move_arg(InitArgs),
395                                              RParenLoc,
396                                              TypeMayContainAuto);
397      } else {
398        assert(InitArgs.size() == 1);
399        Expr *Init = InitArgs.take()[0];
400        SemaRef.AddInitializerToDecl(Var, Init, false, TypeMayContainAuto);
401      }
402    } else {
403      // FIXME: Not too happy about invalidating the declaration
404      // because of a bogus initializer.
405      Var->setInvalidDecl();
406    }
407
408    SemaRef.PopExpressionEvaluationContext();
409  } else if ((!Var->isStaticDataMember() || Var->isOutOfLine()) &&
410             !Var->isCXXForRangeDecl())
411    SemaRef.ActOnUninitializedDecl(Var, false);
412
413  // Diagnose unused local variables with dependent types, where the diagnostic
414  // will have been deferred.
415  if (!Var->isInvalidDecl() && Owner->isFunctionOrMethod() && !Var->isUsed() &&
416      D->getType()->isDependentType())
417    SemaRef.DiagnoseUnusedDecl(Var);
418
419  return Var;
420}
421
422Decl *TemplateDeclInstantiator::VisitAccessSpecDecl(AccessSpecDecl *D) {
423  AccessSpecDecl* AD
424    = AccessSpecDecl::Create(SemaRef.Context, D->getAccess(), Owner,
425                             D->getAccessSpecifierLoc(), D->getColonLoc());
426  Owner->addHiddenDecl(AD);
427  return AD;
428}
429
430Decl *TemplateDeclInstantiator::VisitFieldDecl(FieldDecl *D) {
431  bool Invalid = false;
432  TypeSourceInfo *DI = D->getTypeSourceInfo();
433  if (DI->getType()->isInstantiationDependentType() ||
434      DI->getType()->isVariablyModifiedType())  {
435    DI = SemaRef.SubstType(DI, TemplateArgs,
436                           D->getLocation(), D->getDeclName());
437    if (!DI) {
438      DI = D->getTypeSourceInfo();
439      Invalid = true;
440    } else if (DI->getType()->isFunctionType()) {
441      // C++ [temp.arg.type]p3:
442      //   If a declaration acquires a function type through a type
443      //   dependent on a template-parameter and this causes a
444      //   declaration that does not use the syntactic form of a
445      //   function declarator to have function type, the program is
446      //   ill-formed.
447      SemaRef.Diag(D->getLocation(), diag::err_field_instantiates_to_function)
448        << DI->getType();
449      Invalid = true;
450    }
451  } else {
452    SemaRef.MarkDeclarationsReferencedInType(D->getLocation(), DI->getType());
453  }
454
455  Expr *BitWidth = D->getBitWidth();
456  if (Invalid)
457    BitWidth = 0;
458  else if (BitWidth) {
459    // The bit-width expression is not potentially evaluated.
460    EnterExpressionEvaluationContext Unevaluated(SemaRef, Sema::Unevaluated);
461
462    ExprResult InstantiatedBitWidth
463      = SemaRef.SubstExpr(BitWidth, TemplateArgs);
464    if (InstantiatedBitWidth.isInvalid()) {
465      Invalid = true;
466      BitWidth = 0;
467    } else
468      BitWidth = InstantiatedBitWidth.takeAs<Expr>();
469  }
470
471  FieldDecl *Field = SemaRef.CheckFieldDecl(D->getDeclName(),
472                                            DI->getType(), DI,
473                                            cast<RecordDecl>(Owner),
474                                            D->getLocation(),
475                                            D->isMutable(),
476                                            BitWidth,
477                                            D->hasInClassInitializer(),
478                                            D->getTypeSpecStartLoc(),
479                                            D->getAccess(),
480                                            0);
481  if (!Field) {
482    cast<Decl>(Owner)->setInvalidDecl();
483    return 0;
484  }
485
486  SemaRef.InstantiateAttrs(TemplateArgs, D, Field);
487
488  if (Invalid)
489    Field->setInvalidDecl();
490
491  if (!Field->getDeclName()) {
492    // Keep track of where this decl came from.
493    SemaRef.Context.setInstantiatedFromUnnamedFieldDecl(Field, D);
494  }
495  if (CXXRecordDecl *Parent= dyn_cast<CXXRecordDecl>(Field->getDeclContext())) {
496    if (Parent->isAnonymousStructOrUnion() &&
497        Parent->getRedeclContext()->isFunctionOrMethod())
498      SemaRef.CurrentInstantiationScope->InstantiatedLocal(D, Field);
499  }
500
501  Field->setImplicit(D->isImplicit());
502  Field->setAccess(D->getAccess());
503  Owner->addDecl(Field);
504
505  return Field;
506}
507
508Decl *TemplateDeclInstantiator::VisitIndirectFieldDecl(IndirectFieldDecl *D) {
509  NamedDecl **NamedChain =
510    new (SemaRef.Context)NamedDecl*[D->getChainingSize()];
511
512  int i = 0;
513  for (IndirectFieldDecl::chain_iterator PI =
514       D->chain_begin(), PE = D->chain_end();
515       PI != PE; ++PI) {
516    NamedDecl *Next = SemaRef.FindInstantiatedDecl(D->getLocation(), *PI,
517                                              TemplateArgs);
518    if (!Next)
519      return 0;
520
521    NamedChain[i++] = Next;
522  }
523
524  QualType T = cast<FieldDecl>(NamedChain[i-1])->getType();
525  IndirectFieldDecl* IndirectField
526    = IndirectFieldDecl::Create(SemaRef.Context, Owner, D->getLocation(),
527                                D->getIdentifier(), T,
528                                NamedChain, D->getChainingSize());
529
530
531  IndirectField->setImplicit(D->isImplicit());
532  IndirectField->setAccess(D->getAccess());
533  Owner->addDecl(IndirectField);
534  return IndirectField;
535}
536
537Decl *TemplateDeclInstantiator::VisitFriendDecl(FriendDecl *D) {
538  // Handle friend type expressions by simply substituting template
539  // parameters into the pattern type and checking the result.
540  if (TypeSourceInfo *Ty = D->getFriendType()) {
541    TypeSourceInfo *InstTy;
542    // If this is an unsupported friend, don't bother substituting template
543    // arguments into it. The actual type referred to won't be used by any
544    // parts of Clang, and may not be valid for instantiating. Just use the
545    // same info for the instantiated friend.
546    if (D->isUnsupportedFriend()) {
547      InstTy = Ty;
548    } else {
549      InstTy = SemaRef.SubstType(Ty, TemplateArgs,
550                                 D->getLocation(), DeclarationName());
551    }
552    if (!InstTy)
553      return 0;
554
555    FriendDecl *FD = SemaRef.CheckFriendTypeDecl(D->getFriendLoc(), InstTy);
556    if (!FD)
557      return 0;
558
559    FD->setAccess(AS_public);
560    FD->setUnsupportedFriend(D->isUnsupportedFriend());
561    Owner->addDecl(FD);
562    return FD;
563  }
564
565  NamedDecl *ND = D->getFriendDecl();
566  assert(ND && "friend decl must be a decl or a type!");
567
568  // All of the Visit implementations for the various potential friend
569  // declarations have to be carefully written to work for friend
570  // objects, with the most important detail being that the target
571  // decl should almost certainly not be placed in Owner.
572  Decl *NewND = Visit(ND);
573  if (!NewND) return 0;
574
575  FriendDecl *FD =
576    FriendDecl::Create(SemaRef.Context, Owner, D->getLocation(),
577                       cast<NamedDecl>(NewND), D->getFriendLoc());
578  FD->setAccess(AS_public);
579  FD->setUnsupportedFriend(D->isUnsupportedFriend());
580  Owner->addDecl(FD);
581  return FD;
582}
583
584Decl *TemplateDeclInstantiator::VisitStaticAssertDecl(StaticAssertDecl *D) {
585  Expr *AssertExpr = D->getAssertExpr();
586
587  // The expression in a static assertion is not potentially evaluated.
588  EnterExpressionEvaluationContext Unevaluated(SemaRef, Sema::Unevaluated);
589
590  ExprResult InstantiatedAssertExpr
591    = SemaRef.SubstExpr(AssertExpr, TemplateArgs);
592  if (InstantiatedAssertExpr.isInvalid())
593    return 0;
594
595  ExprResult Message(D->getMessage());
596  D->getMessage();
597  return SemaRef.ActOnStaticAssertDeclaration(D->getLocation(),
598                                              InstantiatedAssertExpr.get(),
599                                              Message.get(),
600                                              D->getRParenLoc());
601}
602
603Decl *TemplateDeclInstantiator::VisitEnumDecl(EnumDecl *D) {
604  EnumDecl *Enum = EnumDecl::Create(SemaRef.Context, Owner, D->getLocStart(),
605                                    D->getLocation(), D->getIdentifier(),
606                                    /*PrevDecl=*/0, D->isScoped(),
607                                    D->isScopedUsingClassTag(), D->isFixed());
608  if (D->isFixed()) {
609    if (TypeSourceInfo* TI = D->getIntegerTypeSourceInfo()) {
610      // If we have type source information for the underlying type, it means it
611      // has been explicitly set by the user. Perform substitution on it before
612      // moving on.
613      SourceLocation UnderlyingLoc = TI->getTypeLoc().getBeginLoc();
614      Enum->setIntegerTypeSourceInfo(SemaRef.SubstType(TI,
615                                                       TemplateArgs,
616                                                       UnderlyingLoc,
617                                                       DeclarationName()));
618
619      if (!Enum->getIntegerTypeSourceInfo())
620        Enum->setIntegerType(SemaRef.Context.IntTy);
621    }
622    else {
623      assert(!D->getIntegerType()->isDependentType()
624             && "Dependent type without type source info");
625      Enum->setIntegerType(D->getIntegerType());
626    }
627  }
628
629  SemaRef.InstantiateAttrs(TemplateArgs, D, Enum);
630
631  Enum->setInstantiationOfMemberEnum(D);
632  Enum->setAccess(D->getAccess());
633  if (SubstQualifier(D, Enum)) return 0;
634  Owner->addDecl(Enum);
635  Enum->startDefinition();
636
637  if (D->getDeclContext()->isFunctionOrMethod())
638    SemaRef.CurrentInstantiationScope->InstantiatedLocal(D, Enum);
639
640  SmallVector<Decl*, 4> Enumerators;
641
642  EnumConstantDecl *LastEnumConst = 0;
643  for (EnumDecl::enumerator_iterator EC = D->enumerator_begin(),
644         ECEnd = D->enumerator_end();
645       EC != ECEnd; ++EC) {
646    // The specified value for the enumerator.
647    ExprResult Value = SemaRef.Owned((Expr *)0);
648    if (Expr *UninstValue = EC->getInitExpr()) {
649      // The enumerator's value expression is not potentially evaluated.
650      EnterExpressionEvaluationContext Unevaluated(SemaRef,
651                                                   Sema::Unevaluated);
652
653      Value = SemaRef.SubstExpr(UninstValue, TemplateArgs);
654    }
655
656    // Drop the initial value and continue.
657    bool isInvalid = false;
658    if (Value.isInvalid()) {
659      Value = SemaRef.Owned((Expr *)0);
660      isInvalid = true;
661    }
662
663    EnumConstantDecl *EnumConst
664      = SemaRef.CheckEnumConstant(Enum, LastEnumConst,
665                                  EC->getLocation(), EC->getIdentifier(),
666                                  Value.get());
667
668    if (isInvalid) {
669      if (EnumConst)
670        EnumConst->setInvalidDecl();
671      Enum->setInvalidDecl();
672    }
673
674    if (EnumConst) {
675      SemaRef.InstantiateAttrs(TemplateArgs, *EC, EnumConst);
676
677      EnumConst->setAccess(Enum->getAccess());
678      Enum->addDecl(EnumConst);
679      Enumerators.push_back(EnumConst);
680      LastEnumConst = EnumConst;
681
682      if (D->getDeclContext()->isFunctionOrMethod()) {
683        // If the enumeration is within a function or method, record the enum
684        // constant as a local.
685        SemaRef.CurrentInstantiationScope->InstantiatedLocal(*EC, EnumConst);
686      }
687    }
688  }
689
690  // FIXME: Fixup LBraceLoc and RBraceLoc
691  // FIXME: Empty Scope and AttributeList (required to handle attribute packed).
692  SemaRef.ActOnEnumBody(Enum->getLocation(), SourceLocation(), SourceLocation(),
693                        Enum,
694                        Enumerators.data(), Enumerators.size(),
695                        0, 0);
696
697  return Enum;
698}
699
700Decl *TemplateDeclInstantiator::VisitEnumConstantDecl(EnumConstantDecl *D) {
701  llvm_unreachable("EnumConstantDecls can only occur within EnumDecls.");
702}
703
704Decl *TemplateDeclInstantiator::VisitClassTemplateDecl(ClassTemplateDecl *D) {
705  bool isFriend = (D->getFriendObjectKind() != Decl::FOK_None);
706
707  // Create a local instantiation scope for this class template, which
708  // will contain the instantiations of the template parameters.
709  LocalInstantiationScope Scope(SemaRef);
710  TemplateParameterList *TempParams = D->getTemplateParameters();
711  TemplateParameterList *InstParams = SubstTemplateParams(TempParams);
712  if (!InstParams)
713    return NULL;
714
715  CXXRecordDecl *Pattern = D->getTemplatedDecl();
716
717  // Instantiate the qualifier.  We have to do this first in case
718  // we're a friend declaration, because if we are then we need to put
719  // the new declaration in the appropriate context.
720  NestedNameSpecifierLoc QualifierLoc = Pattern->getQualifierLoc();
721  if (QualifierLoc) {
722    QualifierLoc = SemaRef.SubstNestedNameSpecifierLoc(QualifierLoc,
723                                                       TemplateArgs);
724    if (!QualifierLoc)
725      return 0;
726  }
727
728  CXXRecordDecl *PrevDecl = 0;
729  ClassTemplateDecl *PrevClassTemplate = 0;
730
731  if (!isFriend && Pattern->getPreviousDeclaration()) {
732    DeclContext::lookup_result Found = Owner->lookup(Pattern->getDeclName());
733    if (Found.first != Found.second) {
734      PrevClassTemplate = dyn_cast<ClassTemplateDecl>(*Found.first);
735      if (PrevClassTemplate)
736        PrevDecl = PrevClassTemplate->getTemplatedDecl();
737    }
738  }
739
740  // If this isn't a friend, then it's a member template, in which
741  // case we just want to build the instantiation in the
742  // specialization.  If it is a friend, we want to build it in
743  // the appropriate context.
744  DeclContext *DC = Owner;
745  if (isFriend) {
746    if (QualifierLoc) {
747      CXXScopeSpec SS;
748      SS.Adopt(QualifierLoc);
749      DC = SemaRef.computeDeclContext(SS);
750      if (!DC) return 0;
751    } else {
752      DC = SemaRef.FindInstantiatedContext(Pattern->getLocation(),
753                                           Pattern->getDeclContext(),
754                                           TemplateArgs);
755    }
756
757    // Look for a previous declaration of the template in the owning
758    // context.
759    LookupResult R(SemaRef, Pattern->getDeclName(), Pattern->getLocation(),
760                   Sema::LookupOrdinaryName, Sema::ForRedeclaration);
761    SemaRef.LookupQualifiedName(R, DC);
762
763    if (R.isSingleResult()) {
764      PrevClassTemplate = R.getAsSingle<ClassTemplateDecl>();
765      if (PrevClassTemplate)
766        PrevDecl = PrevClassTemplate->getTemplatedDecl();
767    }
768
769    if (!PrevClassTemplate && QualifierLoc) {
770      SemaRef.Diag(Pattern->getLocation(), diag::err_not_tag_in_scope)
771        << D->getTemplatedDecl()->getTagKind() << Pattern->getDeclName() << DC
772        << QualifierLoc.getSourceRange();
773      return 0;
774    }
775
776    bool AdoptedPreviousTemplateParams = false;
777    if (PrevClassTemplate) {
778      bool Complain = true;
779
780      // HACK: libstdc++ 4.2.1 contains an ill-formed friend class
781      // template for struct std::tr1::__detail::_Map_base, where the
782      // template parameters of the friend declaration don't match the
783      // template parameters of the original declaration. In this one
784      // case, we don't complain about the ill-formed friend
785      // declaration.
786      if (isFriend && Pattern->getIdentifier() &&
787          Pattern->getIdentifier()->isStr("_Map_base") &&
788          DC->isNamespace() &&
789          cast<NamespaceDecl>(DC)->getIdentifier() &&
790          cast<NamespaceDecl>(DC)->getIdentifier()->isStr("__detail")) {
791        DeclContext *DCParent = DC->getParent();
792        if (DCParent->isNamespace() &&
793            cast<NamespaceDecl>(DCParent)->getIdentifier() &&
794            cast<NamespaceDecl>(DCParent)->getIdentifier()->isStr("tr1")) {
795          DeclContext *DCParent2 = DCParent->getParent();
796          if (DCParent2->isNamespace() &&
797              cast<NamespaceDecl>(DCParent2)->getIdentifier() &&
798              cast<NamespaceDecl>(DCParent2)->getIdentifier()->isStr("std") &&
799              DCParent2->getParent()->isTranslationUnit())
800            Complain = false;
801        }
802      }
803
804      TemplateParameterList *PrevParams
805        = PrevClassTemplate->getTemplateParameters();
806
807      // Make sure the parameter lists match.
808      if (!SemaRef.TemplateParameterListsAreEqual(InstParams, PrevParams,
809                                                  Complain,
810                                                  Sema::TPL_TemplateMatch)) {
811        if (Complain)
812          return 0;
813
814        AdoptedPreviousTemplateParams = true;
815        InstParams = PrevParams;
816      }
817
818      // Do some additional validation, then merge default arguments
819      // from the existing declarations.
820      if (!AdoptedPreviousTemplateParams &&
821          SemaRef.CheckTemplateParameterList(InstParams, PrevParams,
822                                             Sema::TPC_ClassTemplate))
823        return 0;
824    }
825  }
826
827  CXXRecordDecl *RecordInst
828    = CXXRecordDecl::Create(SemaRef.Context, Pattern->getTagKind(), DC,
829                            Pattern->getLocStart(), Pattern->getLocation(),
830                            Pattern->getIdentifier(), PrevDecl,
831                            /*DelayTypeCreation=*/true);
832
833  if (QualifierLoc)
834    RecordInst->setQualifierInfo(QualifierLoc);
835
836  ClassTemplateDecl *Inst
837    = ClassTemplateDecl::Create(SemaRef.Context, DC, D->getLocation(),
838                                D->getIdentifier(), InstParams, RecordInst,
839                                PrevClassTemplate);
840  RecordInst->setDescribedClassTemplate(Inst);
841
842  if (isFriend) {
843    if (PrevClassTemplate)
844      Inst->setAccess(PrevClassTemplate->getAccess());
845    else
846      Inst->setAccess(D->getAccess());
847
848    Inst->setObjectOfFriendDecl(PrevClassTemplate != 0);
849    // TODO: do we want to track the instantiation progeny of this
850    // friend target decl?
851  } else {
852    Inst->setAccess(D->getAccess());
853    if (!PrevClassTemplate)
854      Inst->setInstantiatedFromMemberTemplate(D);
855  }
856
857  // Trigger creation of the type for the instantiation.
858  SemaRef.Context.getInjectedClassNameType(RecordInst,
859                                    Inst->getInjectedClassNameSpecialization());
860
861  // Finish handling of friends.
862  if (isFriend) {
863    DC->makeDeclVisibleInContext(Inst, /*Recoverable*/ false);
864    return Inst;
865  }
866
867  Owner->addDecl(Inst);
868
869  if (!PrevClassTemplate) {
870    // Queue up any out-of-line partial specializations of this member
871    // class template; the client will force their instantiation once
872    // the enclosing class has been instantiated.
873    SmallVector<ClassTemplatePartialSpecializationDecl *, 4> PartialSpecs;
874    D->getPartialSpecializations(PartialSpecs);
875    for (unsigned I = 0, N = PartialSpecs.size(); I != N; ++I)
876      if (PartialSpecs[I]->isOutOfLine())
877        OutOfLinePartialSpecs.push_back(std::make_pair(Inst, PartialSpecs[I]));
878  }
879
880  return Inst;
881}
882
883Decl *
884TemplateDeclInstantiator::VisitClassTemplatePartialSpecializationDecl(
885                                   ClassTemplatePartialSpecializationDecl *D) {
886  ClassTemplateDecl *ClassTemplate = D->getSpecializedTemplate();
887
888  // Lookup the already-instantiated declaration in the instantiation
889  // of the class template and return that.
890  DeclContext::lookup_result Found
891    = Owner->lookup(ClassTemplate->getDeclName());
892  if (Found.first == Found.second)
893    return 0;
894
895  ClassTemplateDecl *InstClassTemplate
896    = dyn_cast<ClassTemplateDecl>(*Found.first);
897  if (!InstClassTemplate)
898    return 0;
899
900  if (ClassTemplatePartialSpecializationDecl *Result
901        = InstClassTemplate->findPartialSpecInstantiatedFromMember(D))
902    return Result;
903
904  return InstantiateClassTemplatePartialSpecialization(InstClassTemplate, D);
905}
906
907Decl *
908TemplateDeclInstantiator::VisitFunctionTemplateDecl(FunctionTemplateDecl *D) {
909  // Create a local instantiation scope for this function template, which
910  // will contain the instantiations of the template parameters and then get
911  // merged with the local instantiation scope for the function template
912  // itself.
913  LocalInstantiationScope Scope(SemaRef);
914
915  TemplateParameterList *TempParams = D->getTemplateParameters();
916  TemplateParameterList *InstParams = SubstTemplateParams(TempParams);
917  if (!InstParams)
918    return NULL;
919
920  FunctionDecl *Instantiated = 0;
921  if (CXXMethodDecl *DMethod = dyn_cast<CXXMethodDecl>(D->getTemplatedDecl()))
922    Instantiated = cast_or_null<FunctionDecl>(VisitCXXMethodDecl(DMethod,
923                                                                 InstParams));
924  else
925    Instantiated = cast_or_null<FunctionDecl>(VisitFunctionDecl(
926                                                          D->getTemplatedDecl(),
927                                                                InstParams));
928
929  if (!Instantiated)
930    return 0;
931
932  Instantiated->setAccess(D->getAccess());
933
934  // Link the instantiated function template declaration to the function
935  // template from which it was instantiated.
936  FunctionTemplateDecl *InstTemplate
937    = Instantiated->getDescribedFunctionTemplate();
938  InstTemplate->setAccess(D->getAccess());
939  assert(InstTemplate &&
940         "VisitFunctionDecl/CXXMethodDecl didn't create a template!");
941
942  bool isFriend = (InstTemplate->getFriendObjectKind() != Decl::FOK_None);
943
944  // Link the instantiation back to the pattern *unless* this is a
945  // non-definition friend declaration.
946  if (!InstTemplate->getInstantiatedFromMemberTemplate() &&
947      !(isFriend && !D->getTemplatedDecl()->isThisDeclarationADefinition()))
948    InstTemplate->setInstantiatedFromMemberTemplate(D);
949
950  // Make declarations visible in the appropriate context.
951  if (!isFriend)
952    Owner->addDecl(InstTemplate);
953
954  return InstTemplate;
955}
956
957Decl *TemplateDeclInstantiator::VisitCXXRecordDecl(CXXRecordDecl *D) {
958  CXXRecordDecl *PrevDecl = 0;
959  if (D->isInjectedClassName())
960    PrevDecl = cast<CXXRecordDecl>(Owner);
961  else if (D->getPreviousDeclaration()) {
962    NamedDecl *Prev = SemaRef.FindInstantiatedDecl(D->getLocation(),
963                                                   D->getPreviousDeclaration(),
964                                                   TemplateArgs);
965    if (!Prev) return 0;
966    PrevDecl = cast<CXXRecordDecl>(Prev);
967  }
968
969  CXXRecordDecl *Record
970    = CXXRecordDecl::Create(SemaRef.Context, D->getTagKind(), Owner,
971                            D->getLocStart(), D->getLocation(),
972                            D->getIdentifier(), PrevDecl);
973
974  // Substitute the nested name specifier, if any.
975  if (SubstQualifier(D, Record))
976    return 0;
977
978  Record->setImplicit(D->isImplicit());
979  // FIXME: Check against AS_none is an ugly hack to work around the issue that
980  // the tag decls introduced by friend class declarations don't have an access
981  // specifier. Remove once this area of the code gets sorted out.
982  if (D->getAccess() != AS_none)
983    Record->setAccess(D->getAccess());
984  if (!D->isInjectedClassName())
985    Record->setInstantiationOfMemberClass(D, TSK_ImplicitInstantiation);
986
987  // If the original function was part of a friend declaration,
988  // inherit its namespace state.
989  if (Decl::FriendObjectKind FOK = D->getFriendObjectKind())
990    Record->setObjectOfFriendDecl(FOK == Decl::FOK_Declared);
991
992  // Make sure that anonymous structs and unions are recorded.
993  if (D->isAnonymousStructOrUnion()) {
994    Record->setAnonymousStructOrUnion(true);
995    if (Record->getDeclContext()->getRedeclContext()->isFunctionOrMethod())
996      SemaRef.CurrentInstantiationScope->InstantiatedLocal(D, Record);
997  }
998
999  Owner->addDecl(Record);
1000  return Record;
1001}
1002
1003/// Normal class members are of more specific types and therefore
1004/// don't make it here.  This function serves two purposes:
1005///   1) instantiating function templates
1006///   2) substituting friend declarations
1007/// FIXME: preserve function definitions in case #2
1008Decl *TemplateDeclInstantiator::VisitFunctionDecl(FunctionDecl *D,
1009                                       TemplateParameterList *TemplateParams) {
1010  // Check whether there is already a function template specialization for
1011  // this declaration.
1012  FunctionTemplateDecl *FunctionTemplate = D->getDescribedFunctionTemplate();
1013  void *InsertPos = 0;
1014  if (FunctionTemplate && !TemplateParams) {
1015    std::pair<const TemplateArgument *, unsigned> Innermost
1016      = TemplateArgs.getInnermost();
1017
1018    FunctionDecl *SpecFunc
1019      = FunctionTemplate->findSpecialization(Innermost.first, Innermost.second,
1020                                             InsertPos);
1021
1022    // If we already have a function template specialization, return it.
1023    if (SpecFunc)
1024      return SpecFunc;
1025  }
1026
1027  bool isFriend;
1028  if (FunctionTemplate)
1029    isFriend = (FunctionTemplate->getFriendObjectKind() != Decl::FOK_None);
1030  else
1031    isFriend = (D->getFriendObjectKind() != Decl::FOK_None);
1032
1033  bool MergeWithParentScope = (TemplateParams != 0) ||
1034    Owner->isFunctionOrMethod() ||
1035    !(isa<Decl>(Owner) &&
1036      cast<Decl>(Owner)->isDefinedOutsideFunctionOrMethod());
1037  LocalInstantiationScope Scope(SemaRef, MergeWithParentScope);
1038
1039  SmallVector<ParmVarDecl *, 4> Params;
1040  TypeSourceInfo *TInfo = D->getTypeSourceInfo();
1041  TInfo = SubstFunctionType(D, Params);
1042  if (!TInfo)
1043    return 0;
1044  QualType T = TInfo->getType();
1045
1046  NestedNameSpecifierLoc QualifierLoc = D->getQualifierLoc();
1047  if (QualifierLoc) {
1048    QualifierLoc = SemaRef.SubstNestedNameSpecifierLoc(QualifierLoc,
1049                                                       TemplateArgs);
1050    if (!QualifierLoc)
1051      return 0;
1052  }
1053
1054  // If we're instantiating a local function declaration, put the result
1055  // in the owner;  otherwise we need to find the instantiated context.
1056  DeclContext *DC;
1057  if (D->getDeclContext()->isFunctionOrMethod())
1058    DC = Owner;
1059  else if (isFriend && QualifierLoc) {
1060    CXXScopeSpec SS;
1061    SS.Adopt(QualifierLoc);
1062    DC = SemaRef.computeDeclContext(SS);
1063    if (!DC) return 0;
1064  } else {
1065    DC = SemaRef.FindInstantiatedContext(D->getLocation(), D->getDeclContext(),
1066                                         TemplateArgs);
1067  }
1068
1069  FunctionDecl *Function =
1070      FunctionDecl::Create(SemaRef.Context, DC, D->getInnerLocStart(),
1071                           D->getLocation(), D->getDeclName(), T, TInfo,
1072                           D->getStorageClass(), D->getStorageClassAsWritten(),
1073                           D->isInlineSpecified(), D->hasWrittenPrototype(),
1074                           /*isConstexpr*/ false);
1075
1076  if (QualifierLoc)
1077    Function->setQualifierInfo(QualifierLoc);
1078
1079  DeclContext *LexicalDC = Owner;
1080  if (!isFriend && D->isOutOfLine()) {
1081    assert(D->getDeclContext()->isFileContext());
1082    LexicalDC = D->getDeclContext();
1083  }
1084
1085  Function->setLexicalDeclContext(LexicalDC);
1086
1087  // Attach the parameters
1088  if (isa<FunctionProtoType>(Function->getType().IgnoreParens())) {
1089    // Adopt the already-instantiated parameters into our own context.
1090    for (unsigned P = 0; P < Params.size(); ++P)
1091      if (Params[P])
1092        Params[P]->setOwningFunction(Function);
1093  } else {
1094    // Since we were instantiated via a typedef of a function type, create
1095    // new parameters.
1096    const FunctionProtoType *Proto
1097      = Function->getType()->getAs<FunctionProtoType>();
1098    assert(Proto && "No function prototype in template instantiation?");
1099    for (FunctionProtoType::arg_type_iterator AI = Proto->arg_type_begin(),
1100         AE = Proto->arg_type_end(); AI != AE; ++AI) {
1101      ParmVarDecl *Param
1102        = SemaRef.BuildParmVarDeclForTypedef(Function, Function->getLocation(),
1103                                             *AI);
1104      Param->setScopeInfo(0, Params.size());
1105      Params.push_back(Param);
1106    }
1107  }
1108  Function->setParams(Params);
1109
1110  SourceLocation InstantiateAtPOI;
1111  if (TemplateParams) {
1112    // Our resulting instantiation is actually a function template, since we
1113    // are substituting only the outer template parameters. For example, given
1114    //
1115    //   template<typename T>
1116    //   struct X {
1117    //     template<typename U> friend void f(T, U);
1118    //   };
1119    //
1120    //   X<int> x;
1121    //
1122    // We are instantiating the friend function template "f" within X<int>,
1123    // which means substituting int for T, but leaving "f" as a friend function
1124    // template.
1125    // Build the function template itself.
1126    FunctionTemplate = FunctionTemplateDecl::Create(SemaRef.Context, DC,
1127                                                    Function->getLocation(),
1128                                                    Function->getDeclName(),
1129                                                    TemplateParams, Function);
1130    Function->setDescribedFunctionTemplate(FunctionTemplate);
1131
1132    FunctionTemplate->setLexicalDeclContext(LexicalDC);
1133
1134    if (isFriend && D->isThisDeclarationADefinition()) {
1135      // TODO: should we remember this connection regardless of whether
1136      // the friend declaration provided a body?
1137      FunctionTemplate->setInstantiatedFromMemberTemplate(
1138                                           D->getDescribedFunctionTemplate());
1139    }
1140  } else if (FunctionTemplate) {
1141    // Record this function template specialization.
1142    std::pair<const TemplateArgument *, unsigned> Innermost
1143      = TemplateArgs.getInnermost();
1144    Function->setFunctionTemplateSpecialization(FunctionTemplate,
1145                            TemplateArgumentList::CreateCopy(SemaRef.Context,
1146                                                             Innermost.first,
1147                                                             Innermost.second),
1148                                                InsertPos);
1149  } else if (isFriend) {
1150    // Note, we need this connection even if the friend doesn't have a body.
1151    // Its body may exist but not have been attached yet due to deferred
1152    // parsing.
1153    // FIXME: It might be cleaner to set this when attaching the body to the
1154    // friend function declaration, however that would require finding all the
1155    // instantiations and modifying them.
1156    Function->setInstantiationOfMemberFunction(D, TSK_ImplicitInstantiation);
1157  }
1158
1159  if (InitFunctionInstantiation(Function, D))
1160    Function->setInvalidDecl();
1161
1162  bool isExplicitSpecialization = false;
1163
1164  LookupResult Previous(SemaRef, Function->getDeclName(), SourceLocation(),
1165                        Sema::LookupOrdinaryName, Sema::ForRedeclaration);
1166
1167  if (DependentFunctionTemplateSpecializationInfo *Info
1168        = D->getDependentSpecializationInfo()) {
1169    assert(isFriend && "non-friend has dependent specialization info?");
1170
1171    // This needs to be set now for future sanity.
1172    Function->setObjectOfFriendDecl(/*HasPrevious*/ true);
1173
1174    // Instantiate the explicit template arguments.
1175    TemplateArgumentListInfo ExplicitArgs(Info->getLAngleLoc(),
1176                                          Info->getRAngleLoc());
1177    if (SemaRef.Subst(Info->getTemplateArgs(), Info->getNumTemplateArgs(),
1178                      ExplicitArgs, TemplateArgs))
1179      return 0;
1180
1181    // Map the candidate templates to their instantiations.
1182    for (unsigned I = 0, E = Info->getNumTemplates(); I != E; ++I) {
1183      Decl *Temp = SemaRef.FindInstantiatedDecl(D->getLocation(),
1184                                                Info->getTemplate(I),
1185                                                TemplateArgs);
1186      if (!Temp) return 0;
1187
1188      Previous.addDecl(cast<FunctionTemplateDecl>(Temp));
1189    }
1190
1191    if (SemaRef.CheckFunctionTemplateSpecialization(Function,
1192                                                    &ExplicitArgs,
1193                                                    Previous))
1194      Function->setInvalidDecl();
1195
1196    isExplicitSpecialization = true;
1197
1198  } else if (TemplateParams || !FunctionTemplate) {
1199    // Look only into the namespace where the friend would be declared to
1200    // find a previous declaration. This is the innermost enclosing namespace,
1201    // as described in ActOnFriendFunctionDecl.
1202    SemaRef.LookupQualifiedName(Previous, DC);
1203
1204    // In C++, the previous declaration we find might be a tag type
1205    // (class or enum). In this case, the new declaration will hide the
1206    // tag type. Note that this does does not apply if we're declaring a
1207    // typedef (C++ [dcl.typedef]p4).
1208    if (Previous.isSingleTagDecl())
1209      Previous.clear();
1210  }
1211
1212  SemaRef.CheckFunctionDeclaration(/*Scope*/ 0, Function, Previous,
1213                                   isExplicitSpecialization);
1214
1215  NamedDecl *PrincipalDecl = (TemplateParams
1216                              ? cast<NamedDecl>(FunctionTemplate)
1217                              : Function);
1218
1219  // If the original function was part of a friend declaration,
1220  // inherit its namespace state and add it to the owner.
1221  if (isFriend) {
1222    NamedDecl *PrevDecl;
1223    if (TemplateParams)
1224      PrevDecl = FunctionTemplate->getPreviousDeclaration();
1225    else
1226      PrevDecl = Function->getPreviousDeclaration();
1227
1228    PrincipalDecl->setObjectOfFriendDecl(PrevDecl != 0);
1229    DC->makeDeclVisibleInContext(PrincipalDecl, /*Recoverable=*/ false);
1230
1231    bool queuedInstantiation = false;
1232
1233    // C++98 [temp.friend]p5: When a function is defined in a friend function
1234    //   declaration in a class template, the function is defined at each
1235    //   instantiation of the class template. The function is defined even if it
1236    //   is never used.
1237    // C++11 [temp.friend]p4: When a function is defined in a friend function
1238    //   declaration in a class template, the function is instantiated when the
1239    //   function is odr-used.
1240    //
1241    // If -Wc++98-compat is enabled, we go through the motions of checking for a
1242    // redefinition, but don't instantiate the function.
1243    if ((!SemaRef.getLangOptions().CPlusPlus0x ||
1244         SemaRef.Diags.getDiagnosticLevel(
1245             diag::warn_cxx98_compat_friend_redefinition,
1246             Function->getLocation())
1247           != DiagnosticsEngine::Ignored) &&
1248        D->isThisDeclarationADefinition()) {
1249      // Check for a function body.
1250      const FunctionDecl *Definition = 0;
1251      if (Function->isDefined(Definition) &&
1252          Definition->getTemplateSpecializationKind() == TSK_Undeclared) {
1253        SemaRef.Diag(Function->getLocation(),
1254                     SemaRef.getLangOptions().CPlusPlus0x ?
1255                       diag::warn_cxx98_compat_friend_redefinition :
1256                       diag::err_redefinition) << Function->getDeclName();
1257        SemaRef.Diag(Definition->getLocation(), diag::note_previous_definition);
1258        if (!SemaRef.getLangOptions().CPlusPlus0x)
1259          Function->setInvalidDecl();
1260      }
1261      // Check for redefinitions due to other instantiations of this or
1262      // a similar friend function.
1263      else for (FunctionDecl::redecl_iterator R = Function->redecls_begin(),
1264                                           REnd = Function->redecls_end();
1265                R != REnd; ++R) {
1266        if (*R == Function)
1267          continue;
1268        switch (R->getFriendObjectKind()) {
1269        case Decl::FOK_None:
1270          if (!SemaRef.getLangOptions().CPlusPlus0x &&
1271              !queuedInstantiation && R->isUsed(false)) {
1272            if (MemberSpecializationInfo *MSInfo
1273                = Function->getMemberSpecializationInfo()) {
1274              if (MSInfo->getPointOfInstantiation().isInvalid()) {
1275                SourceLocation Loc = R->getLocation(); // FIXME
1276                MSInfo->setPointOfInstantiation(Loc);
1277                SemaRef.PendingLocalImplicitInstantiations.push_back(
1278                                                 std::make_pair(Function, Loc));
1279                queuedInstantiation = true;
1280              }
1281            }
1282          }
1283          break;
1284        default:
1285          if (const FunctionDecl *RPattern
1286              = R->getTemplateInstantiationPattern())
1287            if (RPattern->isDefined(RPattern)) {
1288              SemaRef.Diag(Function->getLocation(),
1289                           SemaRef.getLangOptions().CPlusPlus0x ?
1290                             diag::warn_cxx98_compat_friend_redefinition :
1291                             diag::err_redefinition)
1292                << Function->getDeclName();
1293              SemaRef.Diag(R->getLocation(), diag::note_previous_definition);
1294              if (!SemaRef.getLangOptions().CPlusPlus0x)
1295                Function->setInvalidDecl();
1296              break;
1297            }
1298        }
1299      }
1300    }
1301  }
1302
1303  if (Function->isOverloadedOperator() && !DC->isRecord() &&
1304      PrincipalDecl->isInIdentifierNamespace(Decl::IDNS_Ordinary))
1305    PrincipalDecl->setNonMemberOperator();
1306
1307  assert(!D->isDefaulted() && "only methods should be defaulted");
1308  return Function;
1309}
1310
1311Decl *
1312TemplateDeclInstantiator::VisitCXXMethodDecl(CXXMethodDecl *D,
1313                                      TemplateParameterList *TemplateParams,
1314                                      bool IsClassScopeSpecialization) {
1315  FunctionTemplateDecl *FunctionTemplate = D->getDescribedFunctionTemplate();
1316  void *InsertPos = 0;
1317  if (FunctionTemplate && !TemplateParams) {
1318    // We are creating a function template specialization from a function
1319    // template. Check whether there is already a function template
1320    // specialization for this particular set of template arguments.
1321    std::pair<const TemplateArgument *, unsigned> Innermost
1322      = TemplateArgs.getInnermost();
1323
1324    FunctionDecl *SpecFunc
1325      = FunctionTemplate->findSpecialization(Innermost.first, Innermost.second,
1326                                             InsertPos);
1327
1328    // If we already have a function template specialization, return it.
1329    if (SpecFunc)
1330      return SpecFunc;
1331  }
1332
1333  bool isFriend;
1334  if (FunctionTemplate)
1335    isFriend = (FunctionTemplate->getFriendObjectKind() != Decl::FOK_None);
1336  else
1337    isFriend = (D->getFriendObjectKind() != Decl::FOK_None);
1338
1339  bool MergeWithParentScope = (TemplateParams != 0) ||
1340    !(isa<Decl>(Owner) &&
1341      cast<Decl>(Owner)->isDefinedOutsideFunctionOrMethod());
1342  LocalInstantiationScope Scope(SemaRef, MergeWithParentScope);
1343
1344  // Instantiate enclosing template arguments for friends.
1345  SmallVector<TemplateParameterList *, 4> TempParamLists;
1346  unsigned NumTempParamLists = 0;
1347  if (isFriend && (NumTempParamLists = D->getNumTemplateParameterLists())) {
1348    TempParamLists.set_size(NumTempParamLists);
1349    for (unsigned I = 0; I != NumTempParamLists; ++I) {
1350      TemplateParameterList *TempParams = D->getTemplateParameterList(I);
1351      TemplateParameterList *InstParams = SubstTemplateParams(TempParams);
1352      if (!InstParams)
1353        return NULL;
1354      TempParamLists[I] = InstParams;
1355    }
1356  }
1357
1358  SmallVector<ParmVarDecl *, 4> Params;
1359  TypeSourceInfo *TInfo = D->getTypeSourceInfo();
1360  TInfo = SubstFunctionType(D, Params);
1361  if (!TInfo)
1362    return 0;
1363  QualType T = TInfo->getType();
1364
1365  // \brief If the type of this function, after ignoring parentheses,
1366  // is not *directly* a function type, then we're instantiating a function
1367  // that was declared via a typedef, e.g.,
1368  //
1369  //   typedef int functype(int, int);
1370  //   functype func;
1371  //
1372  // In this case, we'll just go instantiate the ParmVarDecls that we
1373  // synthesized in the method declaration.
1374  if (!isa<FunctionProtoType>(T.IgnoreParens())) {
1375    assert(!Params.size() && "Instantiating type could not yield parameters");
1376    SmallVector<QualType, 4> ParamTypes;
1377    if (SemaRef.SubstParmTypes(D->getLocation(), D->param_begin(),
1378                               D->getNumParams(), TemplateArgs, ParamTypes,
1379                               &Params))
1380      return 0;
1381  }
1382
1383  NestedNameSpecifierLoc QualifierLoc = D->getQualifierLoc();
1384  if (QualifierLoc) {
1385    QualifierLoc = SemaRef.SubstNestedNameSpecifierLoc(QualifierLoc,
1386                                                 TemplateArgs);
1387    if (!QualifierLoc)
1388      return 0;
1389  }
1390
1391  DeclContext *DC = Owner;
1392  if (isFriend) {
1393    if (QualifierLoc) {
1394      CXXScopeSpec SS;
1395      SS.Adopt(QualifierLoc);
1396      DC = SemaRef.computeDeclContext(SS);
1397
1398      if (DC && SemaRef.RequireCompleteDeclContext(SS, DC))
1399        return 0;
1400    } else {
1401      DC = SemaRef.FindInstantiatedContext(D->getLocation(),
1402                                           D->getDeclContext(),
1403                                           TemplateArgs);
1404    }
1405    if (!DC) return 0;
1406  }
1407
1408  // Build the instantiated method declaration.
1409  CXXRecordDecl *Record = cast<CXXRecordDecl>(DC);
1410  CXXMethodDecl *Method = 0;
1411
1412  SourceLocation StartLoc = D->getInnerLocStart();
1413  DeclarationNameInfo NameInfo
1414    = SemaRef.SubstDeclarationNameInfo(D->getNameInfo(), TemplateArgs);
1415  if (CXXConstructorDecl *Constructor = dyn_cast<CXXConstructorDecl>(D)) {
1416    Method = CXXConstructorDecl::Create(SemaRef.Context, Record,
1417                                        StartLoc, NameInfo, T, TInfo,
1418                                        Constructor->isExplicit(),
1419                                        Constructor->isInlineSpecified(),
1420                                        false, /*isConstexpr*/ false);
1421  } else if (CXXDestructorDecl *Destructor = dyn_cast<CXXDestructorDecl>(D)) {
1422    Method = CXXDestructorDecl::Create(SemaRef.Context, Record,
1423                                       StartLoc, NameInfo, T, TInfo,
1424                                       Destructor->isInlineSpecified(),
1425                                       false);
1426  } else if (CXXConversionDecl *Conversion = dyn_cast<CXXConversionDecl>(D)) {
1427    Method = CXXConversionDecl::Create(SemaRef.Context, Record,
1428                                       StartLoc, NameInfo, T, TInfo,
1429                                       Conversion->isInlineSpecified(),
1430                                       Conversion->isExplicit(),
1431                                       /*isConstexpr*/ false,
1432                                       Conversion->getLocEnd());
1433  } else {
1434    Method = CXXMethodDecl::Create(SemaRef.Context, Record,
1435                                   StartLoc, NameInfo, T, TInfo,
1436                                   D->isStatic(),
1437                                   D->getStorageClassAsWritten(),
1438                                   D->isInlineSpecified(),
1439                                   /*isConstexpr*/ false, D->getLocEnd());
1440  }
1441
1442  if (QualifierLoc)
1443    Method->setQualifierInfo(QualifierLoc);
1444
1445  if (TemplateParams) {
1446    // Our resulting instantiation is actually a function template, since we
1447    // are substituting only the outer template parameters. For example, given
1448    //
1449    //   template<typename T>
1450    //   struct X {
1451    //     template<typename U> void f(T, U);
1452    //   };
1453    //
1454    //   X<int> x;
1455    //
1456    // We are instantiating the member template "f" within X<int>, which means
1457    // substituting int for T, but leaving "f" as a member function template.
1458    // Build the function template itself.
1459    FunctionTemplate = FunctionTemplateDecl::Create(SemaRef.Context, Record,
1460                                                    Method->getLocation(),
1461                                                    Method->getDeclName(),
1462                                                    TemplateParams, Method);
1463    if (isFriend) {
1464      FunctionTemplate->setLexicalDeclContext(Owner);
1465      FunctionTemplate->setObjectOfFriendDecl(true);
1466    } else if (D->isOutOfLine())
1467      FunctionTemplate->setLexicalDeclContext(D->getLexicalDeclContext());
1468    Method->setDescribedFunctionTemplate(FunctionTemplate);
1469  } else if (FunctionTemplate) {
1470    // Record this function template specialization.
1471    std::pair<const TemplateArgument *, unsigned> Innermost
1472      = TemplateArgs.getInnermost();
1473    Method->setFunctionTemplateSpecialization(FunctionTemplate,
1474                         TemplateArgumentList::CreateCopy(SemaRef.Context,
1475                                                          Innermost.first,
1476                                                          Innermost.second),
1477                                              InsertPos);
1478  } else if (!isFriend) {
1479    // Record that this is an instantiation of a member function.
1480    Method->setInstantiationOfMemberFunction(D, TSK_ImplicitInstantiation);
1481  }
1482
1483  // If we are instantiating a member function defined
1484  // out-of-line, the instantiation will have the same lexical
1485  // context (which will be a namespace scope) as the template.
1486  if (isFriend) {
1487    if (NumTempParamLists)
1488      Method->setTemplateParameterListsInfo(SemaRef.Context,
1489                                            NumTempParamLists,
1490                                            TempParamLists.data());
1491
1492    Method->setLexicalDeclContext(Owner);
1493    Method->setObjectOfFriendDecl(true);
1494  } else if (D->isOutOfLine())
1495    Method->setLexicalDeclContext(D->getLexicalDeclContext());
1496
1497  // Attach the parameters
1498  for (unsigned P = 0; P < Params.size(); ++P)
1499    Params[P]->setOwningFunction(Method);
1500  Method->setParams(Params);
1501
1502  if (InitMethodInstantiation(Method, D))
1503    Method->setInvalidDecl();
1504
1505  LookupResult Previous(SemaRef, NameInfo, Sema::LookupOrdinaryName,
1506                        Sema::ForRedeclaration);
1507
1508  if (!FunctionTemplate || TemplateParams || isFriend) {
1509    SemaRef.LookupQualifiedName(Previous, Record);
1510
1511    // In C++, the previous declaration we find might be a tag type
1512    // (class or enum). In this case, the new declaration will hide the
1513    // tag type. Note that this does does not apply if we're declaring a
1514    // typedef (C++ [dcl.typedef]p4).
1515    if (Previous.isSingleTagDecl())
1516      Previous.clear();
1517  }
1518
1519  if (!IsClassScopeSpecialization)
1520    SemaRef.CheckFunctionDeclaration(0, Method, Previous, false);
1521
1522  if (D->isPure())
1523    SemaRef.CheckPureMethod(Method, SourceRange());
1524
1525  Method->setAccess(D->getAccess());
1526
1527  SemaRef.CheckOverrideControl(Method);
1528
1529  if (FunctionTemplate) {
1530    // If there's a function template, let our caller handle it.
1531  } else if (Method->isInvalidDecl() && !Previous.empty()) {
1532    // Don't hide a (potentially) valid declaration with an invalid one.
1533  } else {
1534    NamedDecl *DeclToAdd = (TemplateParams
1535                            ? cast<NamedDecl>(FunctionTemplate)
1536                            : Method);
1537    if (isFriend)
1538      Record->makeDeclVisibleInContext(DeclToAdd);
1539    else if (!IsClassScopeSpecialization)
1540      Owner->addDecl(DeclToAdd);
1541  }
1542
1543  if (D->isExplicitlyDefaulted()) {
1544    SemaRef.SetDeclDefaulted(Method, Method->getLocation());
1545  } else {
1546    assert(!D->isDefaulted() &&
1547           "should not implicitly default uninstantiated function");
1548  }
1549
1550  return Method;
1551}
1552
1553Decl *TemplateDeclInstantiator::VisitCXXConstructorDecl(CXXConstructorDecl *D) {
1554  return VisitCXXMethodDecl(D);
1555}
1556
1557Decl *TemplateDeclInstantiator::VisitCXXDestructorDecl(CXXDestructorDecl *D) {
1558  return VisitCXXMethodDecl(D);
1559}
1560
1561Decl *TemplateDeclInstantiator::VisitCXXConversionDecl(CXXConversionDecl *D) {
1562  return VisitCXXMethodDecl(D);
1563}
1564
1565ParmVarDecl *TemplateDeclInstantiator::VisitParmVarDecl(ParmVarDecl *D) {
1566  return SemaRef.SubstParmVarDecl(D, TemplateArgs, /*indexAdjustment*/ 0,
1567                                  llvm::Optional<unsigned>());
1568}
1569
1570Decl *TemplateDeclInstantiator::VisitTemplateTypeParmDecl(
1571                                                    TemplateTypeParmDecl *D) {
1572  // TODO: don't always clone when decls are refcounted.
1573  assert(D->getTypeForDecl()->isTemplateTypeParmType());
1574
1575  TemplateTypeParmDecl *Inst =
1576    TemplateTypeParmDecl::Create(SemaRef.Context, Owner,
1577                                 D->getLocStart(), D->getLocation(),
1578                                 D->getDepth() - TemplateArgs.getNumLevels(),
1579                                 D->getIndex(), D->getIdentifier(),
1580                                 D->wasDeclaredWithTypename(),
1581                                 D->isParameterPack());
1582  Inst->setAccess(AS_public);
1583
1584  if (D->hasDefaultArgument())
1585    Inst->setDefaultArgument(D->getDefaultArgumentInfo(), false);
1586
1587  // Introduce this template parameter's instantiation into the instantiation
1588  // scope.
1589  SemaRef.CurrentInstantiationScope->InstantiatedLocal(D, Inst);
1590
1591  return Inst;
1592}
1593
1594Decl *TemplateDeclInstantiator::VisitNonTypeTemplateParmDecl(
1595                                                 NonTypeTemplateParmDecl *D) {
1596  // Substitute into the type of the non-type template parameter.
1597  TypeLoc TL = D->getTypeSourceInfo()->getTypeLoc();
1598  SmallVector<TypeSourceInfo *, 4> ExpandedParameterPackTypesAsWritten;
1599  SmallVector<QualType, 4> ExpandedParameterPackTypes;
1600  bool IsExpandedParameterPack = false;
1601  TypeSourceInfo *DI;
1602  QualType T;
1603  bool Invalid = false;
1604
1605  if (D->isExpandedParameterPack()) {
1606    // The non-type template parameter pack is an already-expanded pack
1607    // expansion of types. Substitute into each of the expanded types.
1608    ExpandedParameterPackTypes.reserve(D->getNumExpansionTypes());
1609    ExpandedParameterPackTypesAsWritten.reserve(D->getNumExpansionTypes());
1610    for (unsigned I = 0, N = D->getNumExpansionTypes(); I != N; ++I) {
1611      TypeSourceInfo *NewDI =SemaRef.SubstType(D->getExpansionTypeSourceInfo(I),
1612                                               TemplateArgs,
1613                                               D->getLocation(),
1614                                               D->getDeclName());
1615      if (!NewDI)
1616        return 0;
1617
1618      ExpandedParameterPackTypesAsWritten.push_back(NewDI);
1619      QualType NewT =SemaRef.CheckNonTypeTemplateParameterType(NewDI->getType(),
1620                                                              D->getLocation());
1621      if (NewT.isNull())
1622        return 0;
1623      ExpandedParameterPackTypes.push_back(NewT);
1624    }
1625
1626    IsExpandedParameterPack = true;
1627    DI = D->getTypeSourceInfo();
1628    T = DI->getType();
1629  } else if (isa<PackExpansionTypeLoc>(TL)) {
1630    // The non-type template parameter pack's type is a pack expansion of types.
1631    // Determine whether we need to expand this parameter pack into separate
1632    // types.
1633    PackExpansionTypeLoc Expansion = cast<PackExpansionTypeLoc>(TL);
1634    TypeLoc Pattern = Expansion.getPatternLoc();
1635    SmallVector<UnexpandedParameterPack, 2> Unexpanded;
1636    SemaRef.collectUnexpandedParameterPacks(Pattern, Unexpanded);
1637
1638    // Determine whether the set of unexpanded parameter packs can and should
1639    // be expanded.
1640    bool Expand = true;
1641    bool RetainExpansion = false;
1642    llvm::Optional<unsigned> OrigNumExpansions
1643      = Expansion.getTypePtr()->getNumExpansions();
1644    llvm::Optional<unsigned> NumExpansions = OrigNumExpansions;
1645    if (SemaRef.CheckParameterPacksForExpansion(Expansion.getEllipsisLoc(),
1646                                                Pattern.getSourceRange(),
1647                                                Unexpanded,
1648                                                TemplateArgs,
1649                                                Expand, RetainExpansion,
1650                                                NumExpansions))
1651      return 0;
1652
1653    if (Expand) {
1654      for (unsigned I = 0; I != *NumExpansions; ++I) {
1655        Sema::ArgumentPackSubstitutionIndexRAII SubstIndex(SemaRef, I);
1656        TypeSourceInfo *NewDI = SemaRef.SubstType(Pattern, TemplateArgs,
1657                                                  D->getLocation(),
1658                                                  D->getDeclName());
1659        if (!NewDI)
1660          return 0;
1661
1662        ExpandedParameterPackTypesAsWritten.push_back(NewDI);
1663        QualType NewT = SemaRef.CheckNonTypeTemplateParameterType(
1664                                                              NewDI->getType(),
1665                                                              D->getLocation());
1666        if (NewT.isNull())
1667          return 0;
1668        ExpandedParameterPackTypes.push_back(NewT);
1669      }
1670
1671      // Note that we have an expanded parameter pack. The "type" of this
1672      // expanded parameter pack is the original expansion type, but callers
1673      // will end up using the expanded parameter pack types for type-checking.
1674      IsExpandedParameterPack = true;
1675      DI = D->getTypeSourceInfo();
1676      T = DI->getType();
1677    } else {
1678      // We cannot fully expand the pack expansion now, so substitute into the
1679      // pattern and create a new pack expansion type.
1680      Sema::ArgumentPackSubstitutionIndexRAII SubstIndex(SemaRef, -1);
1681      TypeSourceInfo *NewPattern = SemaRef.SubstType(Pattern, TemplateArgs,
1682                                                     D->getLocation(),
1683                                                     D->getDeclName());
1684      if (!NewPattern)
1685        return 0;
1686
1687      DI = SemaRef.CheckPackExpansion(NewPattern, Expansion.getEllipsisLoc(),
1688                                      NumExpansions);
1689      if (!DI)
1690        return 0;
1691
1692      T = DI->getType();
1693    }
1694  } else {
1695    // Simple case: substitution into a parameter that is not a parameter pack.
1696    DI = SemaRef.SubstType(D->getTypeSourceInfo(), TemplateArgs,
1697                           D->getLocation(), D->getDeclName());
1698    if (!DI)
1699      return 0;
1700
1701    // Check that this type is acceptable for a non-type template parameter.
1702    T = SemaRef.CheckNonTypeTemplateParameterType(DI->getType(),
1703                                                  D->getLocation());
1704    if (T.isNull()) {
1705      T = SemaRef.Context.IntTy;
1706      Invalid = true;
1707    }
1708  }
1709
1710  NonTypeTemplateParmDecl *Param;
1711  if (IsExpandedParameterPack)
1712    Param = NonTypeTemplateParmDecl::Create(SemaRef.Context, Owner,
1713                                            D->getInnerLocStart(),
1714                                            D->getLocation(),
1715                                    D->getDepth() - TemplateArgs.getNumLevels(),
1716                                            D->getPosition(),
1717                                            D->getIdentifier(), T,
1718                                            DI,
1719                                            ExpandedParameterPackTypes.data(),
1720                                            ExpandedParameterPackTypes.size(),
1721                                    ExpandedParameterPackTypesAsWritten.data());
1722  else
1723    Param = NonTypeTemplateParmDecl::Create(SemaRef.Context, Owner,
1724                                            D->getInnerLocStart(),
1725                                            D->getLocation(),
1726                                    D->getDepth() - TemplateArgs.getNumLevels(),
1727                                            D->getPosition(),
1728                                            D->getIdentifier(), T,
1729                                            D->isParameterPack(), DI);
1730
1731  Param->setAccess(AS_public);
1732  if (Invalid)
1733    Param->setInvalidDecl();
1734
1735  Param->setDefaultArgument(D->getDefaultArgument(), false);
1736
1737  // Introduce this template parameter's instantiation into the instantiation
1738  // scope.
1739  SemaRef.CurrentInstantiationScope->InstantiatedLocal(D, Param);
1740  return Param;
1741}
1742
1743Decl *
1744TemplateDeclInstantiator::VisitTemplateTemplateParmDecl(
1745                                                  TemplateTemplateParmDecl *D) {
1746  // Instantiate the template parameter list of the template template parameter.
1747  TemplateParameterList *TempParams = D->getTemplateParameters();
1748  TemplateParameterList *InstParams;
1749  {
1750    // Perform the actual substitution of template parameters within a new,
1751    // local instantiation scope.
1752    LocalInstantiationScope Scope(SemaRef);
1753    InstParams = SubstTemplateParams(TempParams);
1754    if (!InstParams)
1755      return NULL;
1756  }
1757
1758  // Build the template template parameter.
1759  TemplateTemplateParmDecl *Param
1760    = TemplateTemplateParmDecl::Create(SemaRef.Context, Owner, D->getLocation(),
1761                                   D->getDepth() - TemplateArgs.getNumLevels(),
1762                                       D->getPosition(), D->isParameterPack(),
1763                                       D->getIdentifier(), InstParams);
1764  Param->setDefaultArgument(D->getDefaultArgument(), false);
1765  Param->setAccess(AS_public);
1766
1767  // Introduce this template parameter's instantiation into the instantiation
1768  // scope.
1769  SemaRef.CurrentInstantiationScope->InstantiatedLocal(D, Param);
1770
1771  return Param;
1772}
1773
1774Decl *TemplateDeclInstantiator::VisitUsingDirectiveDecl(UsingDirectiveDecl *D) {
1775  // Using directives are never dependent (and never contain any types or
1776  // expressions), so they require no explicit instantiation work.
1777
1778  UsingDirectiveDecl *Inst
1779    = UsingDirectiveDecl::Create(SemaRef.Context, Owner, D->getLocation(),
1780                                 D->getNamespaceKeyLocation(),
1781                                 D->getQualifierLoc(),
1782                                 D->getIdentLocation(),
1783                                 D->getNominatedNamespace(),
1784                                 D->getCommonAncestor());
1785  Owner->addDecl(Inst);
1786  return Inst;
1787}
1788
1789Decl *TemplateDeclInstantiator::VisitUsingDecl(UsingDecl *D) {
1790
1791  // The nested name specifier may be dependent, for example
1792  //     template <typename T> struct t {
1793  //       struct s1 { T f1(); };
1794  //       struct s2 : s1 { using s1::f1; };
1795  //     };
1796  //     template struct t<int>;
1797  // Here, in using s1::f1, s1 refers to t<T>::s1;
1798  // we need to substitute for t<int>::s1.
1799  NestedNameSpecifierLoc QualifierLoc
1800    = SemaRef.SubstNestedNameSpecifierLoc(D->getQualifierLoc(),
1801                                          TemplateArgs);
1802  if (!QualifierLoc)
1803    return 0;
1804
1805  // The name info is non-dependent, so no transformation
1806  // is required.
1807  DeclarationNameInfo NameInfo = D->getNameInfo();
1808
1809  // We only need to do redeclaration lookups if we're in a class
1810  // scope (in fact, it's not really even possible in non-class
1811  // scopes).
1812  bool CheckRedeclaration = Owner->isRecord();
1813
1814  LookupResult Prev(SemaRef, NameInfo, Sema::LookupUsingDeclName,
1815                    Sema::ForRedeclaration);
1816
1817  UsingDecl *NewUD = UsingDecl::Create(SemaRef.Context, Owner,
1818                                       D->getUsingLocation(),
1819                                       QualifierLoc,
1820                                       NameInfo,
1821                                       D->isTypeName());
1822
1823  CXXScopeSpec SS;
1824  SS.Adopt(QualifierLoc);
1825  if (CheckRedeclaration) {
1826    Prev.setHideTags(false);
1827    SemaRef.LookupQualifiedName(Prev, Owner);
1828
1829    // Check for invalid redeclarations.
1830    if (SemaRef.CheckUsingDeclRedeclaration(D->getUsingLocation(),
1831                                            D->isTypeName(), SS,
1832                                            D->getLocation(), Prev))
1833      NewUD->setInvalidDecl();
1834
1835  }
1836
1837  if (!NewUD->isInvalidDecl() &&
1838      SemaRef.CheckUsingDeclQualifier(D->getUsingLocation(), SS,
1839                                      D->getLocation()))
1840    NewUD->setInvalidDecl();
1841
1842  SemaRef.Context.setInstantiatedFromUsingDecl(NewUD, D);
1843  NewUD->setAccess(D->getAccess());
1844  Owner->addDecl(NewUD);
1845
1846  // Don't process the shadow decls for an invalid decl.
1847  if (NewUD->isInvalidDecl())
1848    return NewUD;
1849
1850  bool isFunctionScope = Owner->isFunctionOrMethod();
1851
1852  // Process the shadow decls.
1853  for (UsingDecl::shadow_iterator I = D->shadow_begin(), E = D->shadow_end();
1854         I != E; ++I) {
1855    UsingShadowDecl *Shadow = *I;
1856    NamedDecl *InstTarget =
1857      cast_or_null<NamedDecl>(SemaRef.FindInstantiatedDecl(
1858                                                          Shadow->getLocation(),
1859                                                        Shadow->getTargetDecl(),
1860                                                           TemplateArgs));
1861    if (!InstTarget)
1862      return 0;
1863
1864    if (CheckRedeclaration &&
1865        SemaRef.CheckUsingShadowDecl(NewUD, InstTarget, Prev))
1866      continue;
1867
1868    UsingShadowDecl *InstShadow
1869      = SemaRef.BuildUsingShadowDecl(/*Scope*/ 0, NewUD, InstTarget);
1870    SemaRef.Context.setInstantiatedFromUsingShadowDecl(InstShadow, Shadow);
1871
1872    if (isFunctionScope)
1873      SemaRef.CurrentInstantiationScope->InstantiatedLocal(Shadow, InstShadow);
1874  }
1875
1876  return NewUD;
1877}
1878
1879Decl *TemplateDeclInstantiator::VisitUsingShadowDecl(UsingShadowDecl *D) {
1880  // Ignore these;  we handle them in bulk when processing the UsingDecl.
1881  return 0;
1882}
1883
1884Decl * TemplateDeclInstantiator
1885    ::VisitUnresolvedUsingTypenameDecl(UnresolvedUsingTypenameDecl *D) {
1886  NestedNameSpecifierLoc QualifierLoc
1887    = SemaRef.SubstNestedNameSpecifierLoc(D->getQualifierLoc(),
1888                                          TemplateArgs);
1889  if (!QualifierLoc)
1890    return 0;
1891
1892  CXXScopeSpec SS;
1893  SS.Adopt(QualifierLoc);
1894
1895  // Since NameInfo refers to a typename, it cannot be a C++ special name.
1896  // Hence, no tranformation is required for it.
1897  DeclarationNameInfo NameInfo(D->getDeclName(), D->getLocation());
1898  NamedDecl *UD =
1899    SemaRef.BuildUsingDeclaration(/*Scope*/ 0, D->getAccess(),
1900                                  D->getUsingLoc(), SS, NameInfo, 0,
1901                                  /*instantiation*/ true,
1902                                  /*typename*/ true, D->getTypenameLoc());
1903  if (UD)
1904    SemaRef.Context.setInstantiatedFromUsingDecl(cast<UsingDecl>(UD), D);
1905
1906  return UD;
1907}
1908
1909Decl * TemplateDeclInstantiator
1910    ::VisitUnresolvedUsingValueDecl(UnresolvedUsingValueDecl *D) {
1911  NestedNameSpecifierLoc QualifierLoc
1912      = SemaRef.SubstNestedNameSpecifierLoc(D->getQualifierLoc(), TemplateArgs);
1913  if (!QualifierLoc)
1914    return 0;
1915
1916  CXXScopeSpec SS;
1917  SS.Adopt(QualifierLoc);
1918
1919  DeclarationNameInfo NameInfo
1920    = SemaRef.SubstDeclarationNameInfo(D->getNameInfo(), TemplateArgs);
1921
1922  NamedDecl *UD =
1923    SemaRef.BuildUsingDeclaration(/*Scope*/ 0, D->getAccess(),
1924                                  D->getUsingLoc(), SS, NameInfo, 0,
1925                                  /*instantiation*/ true,
1926                                  /*typename*/ false, SourceLocation());
1927  if (UD)
1928    SemaRef.Context.setInstantiatedFromUsingDecl(cast<UsingDecl>(UD), D);
1929
1930  return UD;
1931}
1932
1933
1934Decl *TemplateDeclInstantiator::VisitClassScopeFunctionSpecializationDecl(
1935                                     ClassScopeFunctionSpecializationDecl *Decl) {
1936  CXXMethodDecl *OldFD = Decl->getSpecialization();
1937  CXXMethodDecl *NewFD = cast<CXXMethodDecl>(VisitCXXMethodDecl(OldFD, 0, true));
1938
1939  LookupResult Previous(SemaRef, NewFD->getNameInfo(), Sema::LookupOrdinaryName,
1940                        Sema::ForRedeclaration);
1941
1942  SemaRef.LookupQualifiedName(Previous, SemaRef.CurContext);
1943  if (SemaRef.CheckFunctionTemplateSpecialization(NewFD, 0, Previous)) {
1944    NewFD->setInvalidDecl();
1945    return NewFD;
1946  }
1947
1948  // Associate the specialization with the pattern.
1949  FunctionDecl *Specialization = cast<FunctionDecl>(Previous.getFoundDecl());
1950  assert(Specialization && "Class scope Specialization is null");
1951  SemaRef.Context.setClassScopeSpecializationPattern(Specialization, OldFD);
1952
1953  return NewFD;
1954}
1955
1956Decl *Sema::SubstDecl(Decl *D, DeclContext *Owner,
1957                      const MultiLevelTemplateArgumentList &TemplateArgs) {
1958  TemplateDeclInstantiator Instantiator(*this, Owner, TemplateArgs);
1959  if (D->isInvalidDecl())
1960    return 0;
1961
1962  return Instantiator.Visit(D);
1963}
1964
1965/// \brief Instantiates a nested template parameter list in the current
1966/// instantiation context.
1967///
1968/// \param L The parameter list to instantiate
1969///
1970/// \returns NULL if there was an error
1971TemplateParameterList *
1972TemplateDeclInstantiator::SubstTemplateParams(TemplateParameterList *L) {
1973  // Get errors for all the parameters before bailing out.
1974  bool Invalid = false;
1975
1976  unsigned N = L->size();
1977  typedef SmallVector<NamedDecl *, 8> ParamVector;
1978  ParamVector Params;
1979  Params.reserve(N);
1980  for (TemplateParameterList::iterator PI = L->begin(), PE = L->end();
1981       PI != PE; ++PI) {
1982    NamedDecl *D = cast_or_null<NamedDecl>(Visit(*PI));
1983    Params.push_back(D);
1984    Invalid = Invalid || !D || D->isInvalidDecl();
1985  }
1986
1987  // Clean up if we had an error.
1988  if (Invalid)
1989    return NULL;
1990
1991  TemplateParameterList *InstL
1992    = TemplateParameterList::Create(SemaRef.Context, L->getTemplateLoc(),
1993                                    L->getLAngleLoc(), &Params.front(), N,
1994                                    L->getRAngleLoc());
1995  return InstL;
1996}
1997
1998/// \brief Instantiate the declaration of a class template partial
1999/// specialization.
2000///
2001/// \param ClassTemplate the (instantiated) class template that is partially
2002// specialized by the instantiation of \p PartialSpec.
2003///
2004/// \param PartialSpec the (uninstantiated) class template partial
2005/// specialization that we are instantiating.
2006///
2007/// \returns The instantiated partial specialization, if successful; otherwise,
2008/// NULL to indicate an error.
2009ClassTemplatePartialSpecializationDecl *
2010TemplateDeclInstantiator::InstantiateClassTemplatePartialSpecialization(
2011                                            ClassTemplateDecl *ClassTemplate,
2012                          ClassTemplatePartialSpecializationDecl *PartialSpec) {
2013  // Create a local instantiation scope for this class template partial
2014  // specialization, which will contain the instantiations of the template
2015  // parameters.
2016  LocalInstantiationScope Scope(SemaRef);
2017
2018  // Substitute into the template parameters of the class template partial
2019  // specialization.
2020  TemplateParameterList *TempParams = PartialSpec->getTemplateParameters();
2021  TemplateParameterList *InstParams = SubstTemplateParams(TempParams);
2022  if (!InstParams)
2023    return 0;
2024
2025  // Substitute into the template arguments of the class template partial
2026  // specialization.
2027  TemplateArgumentListInfo InstTemplateArgs; // no angle locations
2028  if (SemaRef.Subst(PartialSpec->getTemplateArgsAsWritten(),
2029                    PartialSpec->getNumTemplateArgsAsWritten(),
2030                    InstTemplateArgs, TemplateArgs))
2031    return 0;
2032
2033  // Check that the template argument list is well-formed for this
2034  // class template.
2035  SmallVector<TemplateArgument, 4> Converted;
2036  if (SemaRef.CheckTemplateArgumentList(ClassTemplate,
2037                                        PartialSpec->getLocation(),
2038                                        InstTemplateArgs,
2039                                        false,
2040                                        Converted))
2041    return 0;
2042
2043  // Figure out where to insert this class template partial specialization
2044  // in the member template's set of class template partial specializations.
2045  void *InsertPos = 0;
2046  ClassTemplateSpecializationDecl *PrevDecl
2047    = ClassTemplate->findPartialSpecialization(Converted.data(),
2048                                               Converted.size(), InsertPos);
2049
2050  // Build the canonical type that describes the converted template
2051  // arguments of the class template partial specialization.
2052  QualType CanonType
2053    = SemaRef.Context.getTemplateSpecializationType(TemplateName(ClassTemplate),
2054                                                    Converted.data(),
2055                                                    Converted.size());
2056
2057  // Build the fully-sugared type for this class template
2058  // specialization as the user wrote in the specialization
2059  // itself. This means that we'll pretty-print the type retrieved
2060  // from the specialization's declaration the way that the user
2061  // actually wrote the specialization, rather than formatting the
2062  // name based on the "canonical" representation used to store the
2063  // template arguments in the specialization.
2064  TypeSourceInfo *WrittenTy
2065    = SemaRef.Context.getTemplateSpecializationTypeInfo(
2066                                                    TemplateName(ClassTemplate),
2067                                                    PartialSpec->getLocation(),
2068                                                    InstTemplateArgs,
2069                                                    CanonType);
2070
2071  if (PrevDecl) {
2072    // We've already seen a partial specialization with the same template
2073    // parameters and template arguments. This can happen, for example, when
2074    // substituting the outer template arguments ends up causing two
2075    // class template partial specializations of a member class template
2076    // to have identical forms, e.g.,
2077    //
2078    //   template<typename T, typename U>
2079    //   struct Outer {
2080    //     template<typename X, typename Y> struct Inner;
2081    //     template<typename Y> struct Inner<T, Y>;
2082    //     template<typename Y> struct Inner<U, Y>;
2083    //   };
2084    //
2085    //   Outer<int, int> outer; // error: the partial specializations of Inner
2086    //                          // have the same signature.
2087    SemaRef.Diag(PartialSpec->getLocation(), diag::err_partial_spec_redeclared)
2088      << WrittenTy->getType();
2089    SemaRef.Diag(PrevDecl->getLocation(), diag::note_prev_partial_spec_here)
2090      << SemaRef.Context.getTypeDeclType(PrevDecl);
2091    return 0;
2092  }
2093
2094
2095  // Create the class template partial specialization declaration.
2096  ClassTemplatePartialSpecializationDecl *InstPartialSpec
2097    = ClassTemplatePartialSpecializationDecl::Create(SemaRef.Context,
2098                                                     PartialSpec->getTagKind(),
2099                                                     Owner,
2100                                                     PartialSpec->getLocStart(),
2101                                                     PartialSpec->getLocation(),
2102                                                     InstParams,
2103                                                     ClassTemplate,
2104                                                     Converted.data(),
2105                                                     Converted.size(),
2106                                                     InstTemplateArgs,
2107                                                     CanonType,
2108                                                     0,
2109                             ClassTemplate->getNextPartialSpecSequenceNumber());
2110  // Substitute the nested name specifier, if any.
2111  if (SubstQualifier(PartialSpec, InstPartialSpec))
2112    return 0;
2113
2114  InstPartialSpec->setInstantiatedFromMember(PartialSpec);
2115  InstPartialSpec->setTypeAsWritten(WrittenTy);
2116
2117  // Add this partial specialization to the set of class template partial
2118  // specializations.
2119  ClassTemplate->AddPartialSpecialization(InstPartialSpec, InsertPos);
2120  return InstPartialSpec;
2121}
2122
2123TypeSourceInfo*
2124TemplateDeclInstantiator::SubstFunctionType(FunctionDecl *D,
2125                              SmallVectorImpl<ParmVarDecl *> &Params) {
2126  TypeSourceInfo *OldTInfo = D->getTypeSourceInfo();
2127  assert(OldTInfo && "substituting function without type source info");
2128  assert(Params.empty() && "parameter vector is non-empty at start");
2129  TypeSourceInfo *NewTInfo
2130    = SemaRef.SubstFunctionDeclType(OldTInfo, TemplateArgs,
2131                                    D->getTypeSpecStartLoc(),
2132                                    D->getDeclName());
2133  if (!NewTInfo)
2134    return 0;
2135
2136  if (NewTInfo != OldTInfo) {
2137    // Get parameters from the new type info.
2138    TypeLoc OldTL = OldTInfo->getTypeLoc().IgnoreParens();
2139    if (FunctionProtoTypeLoc *OldProtoLoc
2140                                  = dyn_cast<FunctionProtoTypeLoc>(&OldTL)) {
2141      TypeLoc NewTL = NewTInfo->getTypeLoc().IgnoreParens();
2142      FunctionProtoTypeLoc *NewProtoLoc = cast<FunctionProtoTypeLoc>(&NewTL);
2143      assert(NewProtoLoc && "Missing prototype?");
2144      unsigned NewIdx = 0, NumNewParams = NewProtoLoc->getNumArgs();
2145      for (unsigned OldIdx = 0, NumOldParams = OldProtoLoc->getNumArgs();
2146           OldIdx != NumOldParams; ++OldIdx) {
2147        ParmVarDecl *OldParam = OldProtoLoc->getArg(OldIdx);
2148        if (!OldParam->isParameterPack() ||
2149            (NewIdx < NumNewParams &&
2150             NewProtoLoc->getArg(NewIdx)->isParameterPack())) {
2151          // Simple case: normal parameter, or a parameter pack that's
2152          // instantiated to a (still-dependent) parameter pack.
2153          ParmVarDecl *NewParam = NewProtoLoc->getArg(NewIdx++);
2154          Params.push_back(NewParam);
2155          SemaRef.CurrentInstantiationScope->InstantiatedLocal(OldParam,
2156                                                               NewParam);
2157          continue;
2158        }
2159
2160        // Parameter pack: make the instantiation an argument pack.
2161        SemaRef.CurrentInstantiationScope->MakeInstantiatedLocalArgPack(
2162                                                                      OldParam);
2163        unsigned NumArgumentsInExpansion
2164          = SemaRef.getNumArgumentsInExpansion(OldParam->getType(),
2165                                               TemplateArgs);
2166        while (NumArgumentsInExpansion--) {
2167          ParmVarDecl *NewParam = NewProtoLoc->getArg(NewIdx++);
2168          Params.push_back(NewParam);
2169          SemaRef.CurrentInstantiationScope->InstantiatedLocalPackArg(OldParam,
2170                                                                      NewParam);
2171        }
2172      }
2173    }
2174  } else {
2175    // The function type itself was not dependent and therefore no
2176    // substitution occurred. However, we still need to instantiate
2177    // the function parameters themselves.
2178    TypeLoc OldTL = OldTInfo->getTypeLoc().IgnoreParens();
2179    if (FunctionProtoTypeLoc *OldProtoLoc
2180                                    = dyn_cast<FunctionProtoTypeLoc>(&OldTL)) {
2181      for (unsigned i = 0, i_end = OldProtoLoc->getNumArgs(); i != i_end; ++i) {
2182        ParmVarDecl *Parm = VisitParmVarDecl(OldProtoLoc->getArg(i));
2183        if (!Parm)
2184          return 0;
2185        Params.push_back(Parm);
2186      }
2187    }
2188  }
2189  return NewTInfo;
2190}
2191
2192/// \brief Initializes the common fields of an instantiation function
2193/// declaration (New) from the corresponding fields of its template (Tmpl).
2194///
2195/// \returns true if there was an error
2196bool
2197TemplateDeclInstantiator::InitFunctionInstantiation(FunctionDecl *New,
2198                                                    FunctionDecl *Tmpl) {
2199  if (Tmpl->isDeletedAsWritten())
2200    New->setDeletedAsWritten();
2201
2202  // If we are performing substituting explicitly-specified template arguments
2203  // or deduced template arguments into a function template and we reach this
2204  // point, we are now past the point where SFINAE applies and have committed
2205  // to keeping the new function template specialization. We therefore
2206  // convert the active template instantiation for the function template
2207  // into a template instantiation for this specific function template
2208  // specialization, which is not a SFINAE context, so that we diagnose any
2209  // further errors in the declaration itself.
2210  typedef Sema::ActiveTemplateInstantiation ActiveInstType;
2211  ActiveInstType &ActiveInst = SemaRef.ActiveTemplateInstantiations.back();
2212  if (ActiveInst.Kind == ActiveInstType::ExplicitTemplateArgumentSubstitution ||
2213      ActiveInst.Kind == ActiveInstType::DeducedTemplateArgumentSubstitution) {
2214    if (FunctionTemplateDecl *FunTmpl
2215          = dyn_cast<FunctionTemplateDecl>((Decl *)ActiveInst.Entity)) {
2216      assert(FunTmpl->getTemplatedDecl() == Tmpl &&
2217             "Deduction from the wrong function template?");
2218      (void) FunTmpl;
2219      ActiveInst.Kind = ActiveInstType::TemplateInstantiation;
2220      ActiveInst.Entity = reinterpret_cast<uintptr_t>(New);
2221      --SemaRef.NonInstantiationEntries;
2222    }
2223  }
2224
2225  const FunctionProtoType *Proto = Tmpl->getType()->getAs<FunctionProtoType>();
2226  assert(Proto && "Function template without prototype?");
2227
2228  if (Proto->hasExceptionSpec() || Proto->getNoReturnAttr()) {
2229    // The function has an exception specification or a "noreturn"
2230    // attribute. Substitute into each of the exception types.
2231    SmallVector<QualType, 4> Exceptions;
2232    for (unsigned I = 0, N = Proto->getNumExceptions(); I != N; ++I) {
2233      // FIXME: Poor location information!
2234      if (const PackExpansionType *PackExpansion
2235            = Proto->getExceptionType(I)->getAs<PackExpansionType>()) {
2236        // We have a pack expansion. Instantiate it.
2237        SmallVector<UnexpandedParameterPack, 2> Unexpanded;
2238        SemaRef.collectUnexpandedParameterPacks(PackExpansion->getPattern(),
2239                                                Unexpanded);
2240        assert(!Unexpanded.empty() &&
2241               "Pack expansion without parameter packs?");
2242
2243        bool Expand = false;
2244        bool RetainExpansion = false;
2245        llvm::Optional<unsigned> NumExpansions
2246                                          = PackExpansion->getNumExpansions();
2247        if (SemaRef.CheckParameterPacksForExpansion(New->getLocation(),
2248                                                    SourceRange(),
2249                                                    Unexpanded,
2250                                                    TemplateArgs,
2251                                                    Expand,
2252                                                    RetainExpansion,
2253                                                    NumExpansions))
2254          break;
2255
2256        if (!Expand) {
2257          // We can't expand this pack expansion into separate arguments yet;
2258          // just substitute into the pattern and create a new pack expansion
2259          // type.
2260          Sema::ArgumentPackSubstitutionIndexRAII SubstIndex(SemaRef, -1);
2261          QualType T = SemaRef.SubstType(PackExpansion->getPattern(),
2262                                         TemplateArgs,
2263                                       New->getLocation(), New->getDeclName());
2264          if (T.isNull())
2265            break;
2266
2267          T = SemaRef.Context.getPackExpansionType(T, NumExpansions);
2268          Exceptions.push_back(T);
2269          continue;
2270        }
2271
2272        // Substitute into the pack expansion pattern for each template
2273        bool Invalid = false;
2274        for (unsigned ArgIdx = 0; ArgIdx != *NumExpansions; ++ArgIdx) {
2275          Sema::ArgumentPackSubstitutionIndexRAII SubstIndex(SemaRef, ArgIdx);
2276
2277          QualType T = SemaRef.SubstType(PackExpansion->getPattern(),
2278                                         TemplateArgs,
2279                                       New->getLocation(), New->getDeclName());
2280          if (T.isNull()) {
2281            Invalid = true;
2282            break;
2283          }
2284
2285          Exceptions.push_back(T);
2286        }
2287
2288        if (Invalid)
2289          break;
2290
2291        continue;
2292      }
2293
2294      QualType T
2295        = SemaRef.SubstType(Proto->getExceptionType(I), TemplateArgs,
2296                            New->getLocation(), New->getDeclName());
2297      if (T.isNull() ||
2298          SemaRef.CheckSpecifiedExceptionType(T, New->getLocation()))
2299        continue;
2300
2301      Exceptions.push_back(T);
2302    }
2303    Expr *NoexceptExpr = 0;
2304    if (Expr *OldNoexceptExpr = Proto->getNoexceptExpr()) {
2305      EnterExpressionEvaluationContext Unevaluated(SemaRef, Sema::Unevaluated);
2306      ExprResult E = SemaRef.SubstExpr(OldNoexceptExpr, TemplateArgs);
2307      if (E.isUsable())
2308        E = SemaRef.CheckBooleanCondition(E.get(), E.get()->getLocStart());
2309
2310      if (E.isUsable()) {
2311        SourceLocation ErrLoc;
2312        llvm::APSInt NoexceptVal;
2313        NoexceptExpr = E.take();
2314        if (!NoexceptExpr->isTypeDependent() &&
2315            !NoexceptExpr->isValueDependent() &&
2316            !NoexceptExpr->isIntegerConstantExpr(NoexceptVal, SemaRef.Context,
2317                                                 &ErrLoc, /*evaluated=*/false)){
2318          SemaRef.Diag(ErrLoc, diag::err_noexcept_needs_constant_expression)
2319            << NoexceptExpr->getSourceRange();
2320          NoexceptExpr = 0;
2321        }
2322      }
2323    }
2324
2325    // Rebuild the function type
2326
2327    FunctionProtoType::ExtProtoInfo EPI = Proto->getExtProtoInfo();
2328    EPI.ExceptionSpecType = Proto->getExceptionSpecType();
2329    EPI.NumExceptions = Exceptions.size();
2330    EPI.Exceptions = Exceptions.data();
2331    EPI.NoexceptExpr = NoexceptExpr;
2332    EPI.ExtInfo = Proto->getExtInfo();
2333
2334    const FunctionProtoType *NewProto
2335      = New->getType()->getAs<FunctionProtoType>();
2336    assert(NewProto && "Template instantiation without function prototype?");
2337    New->setType(SemaRef.Context.getFunctionType(NewProto->getResultType(),
2338                                                 NewProto->arg_type_begin(),
2339                                                 NewProto->getNumArgs(),
2340                                                 EPI));
2341  }
2342
2343  // C++0x [dcl.constexpr]p6: If the instantiated template specialization of
2344  // a constexpr function template satisfies the requirements for a constexpr
2345  // function, then it is a constexpr function.
2346  if (Tmpl->isConstexpr() &&
2347      SemaRef.CheckConstexprFunctionDecl(New, Sema::CCK_Instantiation))
2348    New->setConstexpr(true);
2349
2350  const FunctionDecl* Definition = Tmpl;
2351
2352  // Get the definition. Leaves the variable unchanged if undefined.
2353  Tmpl->isDefined(Definition);
2354
2355  SemaRef.InstantiateAttrs(TemplateArgs, Definition, New);
2356
2357  return false;
2358}
2359
2360/// \brief Initializes common fields of an instantiated method
2361/// declaration (New) from the corresponding fields of its template
2362/// (Tmpl).
2363///
2364/// \returns true if there was an error
2365bool
2366TemplateDeclInstantiator::InitMethodInstantiation(CXXMethodDecl *New,
2367                                                  CXXMethodDecl *Tmpl) {
2368  if (InitFunctionInstantiation(New, Tmpl))
2369    return true;
2370
2371  New->setAccess(Tmpl->getAccess());
2372  if (Tmpl->isVirtualAsWritten())
2373    New->setVirtualAsWritten(true);
2374
2375  // FIXME: attributes
2376  // FIXME: New needs a pointer to Tmpl
2377  return false;
2378}
2379
2380/// \brief Instantiate the definition of the given function from its
2381/// template.
2382///
2383/// \param PointOfInstantiation the point at which the instantiation was
2384/// required. Note that this is not precisely a "point of instantiation"
2385/// for the function, but it's close.
2386///
2387/// \param Function the already-instantiated declaration of a
2388/// function template specialization or member function of a class template
2389/// specialization.
2390///
2391/// \param Recursive if true, recursively instantiates any functions that
2392/// are required by this instantiation.
2393///
2394/// \param DefinitionRequired if true, then we are performing an explicit
2395/// instantiation where the body of the function is required. Complain if
2396/// there is no such body.
2397void Sema::InstantiateFunctionDefinition(SourceLocation PointOfInstantiation,
2398                                         FunctionDecl *Function,
2399                                         bool Recursive,
2400                                         bool DefinitionRequired) {
2401  if (Function->isInvalidDecl() || Function->isDefined())
2402    return;
2403
2404  // Never instantiate an explicit specialization except if it is a class scope
2405  // explicit specialization.
2406  if (Function->getTemplateSpecializationKind() == TSK_ExplicitSpecialization &&
2407      !Function->getClassScopeSpecializationPattern())
2408    return;
2409
2410  // Find the function body that we'll be substituting.
2411  const FunctionDecl *PatternDecl = Function->getTemplateInstantiationPattern();
2412  assert(PatternDecl && "instantiating a non-template");
2413
2414  Stmt *Pattern = PatternDecl->getBody(PatternDecl);
2415  assert(PatternDecl && "template definition is not a template");
2416  if (!Pattern) {
2417    // Try to find a defaulted definition
2418    PatternDecl->isDefined(PatternDecl);
2419  }
2420  assert(PatternDecl && "template definition is not a template");
2421
2422  // Postpone late parsed template instantiations.
2423  if (PatternDecl->isLateTemplateParsed() &&
2424      !LateTemplateParser) {
2425    PendingInstantiations.push_back(
2426      std::make_pair(Function, PointOfInstantiation));
2427    return;
2428  }
2429
2430  // Call the LateTemplateParser callback if there a need to late parse
2431  // a templated function definition.
2432  if (!Pattern && PatternDecl->isLateTemplateParsed() &&
2433      LateTemplateParser) {
2434    LateTemplateParser(OpaqueParser, PatternDecl);
2435    Pattern = PatternDecl->getBody(PatternDecl);
2436  }
2437
2438  if (!Pattern && !PatternDecl->isDefaulted()) {
2439    if (DefinitionRequired) {
2440      if (Function->getPrimaryTemplate())
2441        Diag(PointOfInstantiation,
2442             diag::err_explicit_instantiation_undefined_func_template)
2443          << Function->getPrimaryTemplate();
2444      else
2445        Diag(PointOfInstantiation,
2446             diag::err_explicit_instantiation_undefined_member)
2447          << 1 << Function->getDeclName() << Function->getDeclContext();
2448
2449      if (PatternDecl)
2450        Diag(PatternDecl->getLocation(),
2451             diag::note_explicit_instantiation_here);
2452      Function->setInvalidDecl();
2453    } else if (Function->getTemplateSpecializationKind()
2454                 == TSK_ExplicitInstantiationDefinition) {
2455      PendingInstantiations.push_back(
2456        std::make_pair(Function, PointOfInstantiation));
2457    }
2458
2459    return;
2460  }
2461
2462  // C++0x [temp.explicit]p9:
2463  //   Except for inline functions, other explicit instantiation declarations
2464  //   have the effect of suppressing the implicit instantiation of the entity
2465  //   to which they refer.
2466  if (Function->getTemplateSpecializationKind()
2467        == TSK_ExplicitInstantiationDeclaration &&
2468      !PatternDecl->isInlined())
2469    return;
2470
2471  InstantiatingTemplate Inst(*this, PointOfInstantiation, Function);
2472  if (Inst)
2473    return;
2474
2475  // If we're performing recursive template instantiation, create our own
2476  // queue of pending implicit instantiations that we will instantiate later,
2477  // while we're still within our own instantiation context.
2478  SmallVector<VTableUse, 16> SavedVTableUses;
2479  std::deque<PendingImplicitInstantiation> SavedPendingInstantiations;
2480  if (Recursive) {
2481    VTableUses.swap(SavedVTableUses);
2482    PendingInstantiations.swap(SavedPendingInstantiations);
2483  }
2484
2485  EnterExpressionEvaluationContext EvalContext(*this,
2486                                               Sema::PotentiallyEvaluated);
2487  ActOnStartOfFunctionDef(0, Function);
2488
2489  // Introduce a new scope where local variable instantiations will be
2490  // recorded, unless we're actually a member function within a local
2491  // class, in which case we need to merge our results with the parent
2492  // scope (of the enclosing function).
2493  bool MergeWithParentScope = false;
2494  if (CXXRecordDecl *Rec = dyn_cast<CXXRecordDecl>(Function->getDeclContext()))
2495    MergeWithParentScope = Rec->isLocalClass();
2496
2497  LocalInstantiationScope Scope(*this, MergeWithParentScope);
2498
2499  // Introduce the instantiated function parameters into the local
2500  // instantiation scope, and set the parameter names to those used
2501  // in the template.
2502  unsigned FParamIdx = 0;
2503  for (unsigned I = 0, N = PatternDecl->getNumParams(); I != N; ++I) {
2504    const ParmVarDecl *PatternParam = PatternDecl->getParamDecl(I);
2505    if (!PatternParam->isParameterPack()) {
2506      // Simple case: not a parameter pack.
2507      assert(FParamIdx < Function->getNumParams());
2508      ParmVarDecl *FunctionParam = Function->getParamDecl(I);
2509      FunctionParam->setDeclName(PatternParam->getDeclName());
2510      Scope.InstantiatedLocal(PatternParam, FunctionParam);
2511      ++FParamIdx;
2512      continue;
2513    }
2514
2515    // Expand the parameter pack.
2516    Scope.MakeInstantiatedLocalArgPack(PatternParam);
2517    for (unsigned NumFParams = Function->getNumParams();
2518         FParamIdx < NumFParams;
2519         ++FParamIdx) {
2520      ParmVarDecl *FunctionParam = Function->getParamDecl(FParamIdx);
2521      FunctionParam->setDeclName(PatternParam->getDeclName());
2522      Scope.InstantiatedLocalPackArg(PatternParam, FunctionParam);
2523    }
2524  }
2525
2526  // Enter the scope of this instantiation. We don't use
2527  // PushDeclContext because we don't have a scope.
2528  Sema::ContextRAII savedContext(*this, Function);
2529
2530  MultiLevelTemplateArgumentList TemplateArgs =
2531    getTemplateInstantiationArgs(Function, 0, false, PatternDecl);
2532
2533  if (PatternDecl->isDefaulted()) {
2534    ActOnFinishFunctionBody(Function, 0, /*IsInstantiation=*/true);
2535
2536    SetDeclDefaulted(Function, PatternDecl->getLocation());
2537  } else {
2538    // If this is a constructor, instantiate the member initializers.
2539    if (const CXXConstructorDecl *Ctor =
2540          dyn_cast<CXXConstructorDecl>(PatternDecl)) {
2541      InstantiateMemInitializers(cast<CXXConstructorDecl>(Function), Ctor,
2542                                 TemplateArgs);
2543    }
2544
2545    // Instantiate the function body.
2546    StmtResult Body = SubstStmt(Pattern, TemplateArgs);
2547
2548    if (Body.isInvalid())
2549      Function->setInvalidDecl();
2550
2551    ActOnFinishFunctionBody(Function, Body.get(),
2552                            /*IsInstantiation=*/true);
2553  }
2554
2555  PerformDependentDiagnostics(PatternDecl, TemplateArgs);
2556
2557  savedContext.pop();
2558
2559  DeclGroupRef DG(Function);
2560  Consumer.HandleTopLevelDecl(DG);
2561
2562  // This class may have local implicit instantiations that need to be
2563  // instantiation within this scope.
2564  PerformPendingInstantiations(/*LocalOnly=*/true);
2565  Scope.Exit();
2566
2567  if (Recursive) {
2568    // Define any pending vtables.
2569    DefineUsedVTables();
2570
2571    // Instantiate any pending implicit instantiations found during the
2572    // instantiation of this template.
2573    PerformPendingInstantiations();
2574
2575    // Restore the set of pending vtables.
2576    assert(VTableUses.empty() &&
2577           "VTableUses should be empty before it is discarded.");
2578    VTableUses.swap(SavedVTableUses);
2579
2580    // Restore the set of pending implicit instantiations.
2581    assert(PendingInstantiations.empty() &&
2582           "PendingInstantiations should be empty before it is discarded.");
2583    PendingInstantiations.swap(SavedPendingInstantiations);
2584  }
2585}
2586
2587/// \brief Instantiate the definition of the given variable from its
2588/// template.
2589///
2590/// \param PointOfInstantiation the point at which the instantiation was
2591/// required. Note that this is not precisely a "point of instantiation"
2592/// for the function, but it's close.
2593///
2594/// \param Var the already-instantiated declaration of a static member
2595/// variable of a class template specialization.
2596///
2597/// \param Recursive if true, recursively instantiates any functions that
2598/// are required by this instantiation.
2599///
2600/// \param DefinitionRequired if true, then we are performing an explicit
2601/// instantiation where an out-of-line definition of the member variable
2602/// is required. Complain if there is no such definition.
2603void Sema::InstantiateStaticDataMemberDefinition(
2604                                          SourceLocation PointOfInstantiation,
2605                                                 VarDecl *Var,
2606                                                 bool Recursive,
2607                                                 bool DefinitionRequired) {
2608  if (Var->isInvalidDecl())
2609    return;
2610
2611  // Find the out-of-line definition of this static data member.
2612  VarDecl *Def = Var->getInstantiatedFromStaticDataMember();
2613  assert(Def && "This data member was not instantiated from a template?");
2614  assert(Def->isStaticDataMember() && "Not a static data member?");
2615  Def = Def->getOutOfLineDefinition();
2616
2617  if (!Def) {
2618    // We did not find an out-of-line definition of this static data member,
2619    // so we won't perform any instantiation. Rather, we rely on the user to
2620    // instantiate this definition (or provide a specialization for it) in
2621    // another translation unit.
2622    if (DefinitionRequired) {
2623      Def = Var->getInstantiatedFromStaticDataMember();
2624      Diag(PointOfInstantiation,
2625           diag::err_explicit_instantiation_undefined_member)
2626        << 2 << Var->getDeclName() << Var->getDeclContext();
2627      Diag(Def->getLocation(), diag::note_explicit_instantiation_here);
2628    } else if (Var->getTemplateSpecializationKind()
2629                 == TSK_ExplicitInstantiationDefinition) {
2630      PendingInstantiations.push_back(
2631        std::make_pair(Var, PointOfInstantiation));
2632    }
2633
2634    return;
2635  }
2636
2637  // Never instantiate an explicit specialization.
2638  if (Var->getTemplateSpecializationKind() == TSK_ExplicitSpecialization)
2639    return;
2640
2641  // C++0x [temp.explicit]p9:
2642  //   Except for inline functions, other explicit instantiation declarations
2643  //   have the effect of suppressing the implicit instantiation of the entity
2644  //   to which they refer.
2645  if (Var->getTemplateSpecializationKind()
2646        == TSK_ExplicitInstantiationDeclaration)
2647    return;
2648
2649  // If we already have a definition, we're done.
2650  if (Var->getDefinition())
2651    return;
2652
2653  InstantiatingTemplate Inst(*this, PointOfInstantiation, Var);
2654  if (Inst)
2655    return;
2656
2657  // If we're performing recursive template instantiation, create our own
2658  // queue of pending implicit instantiations that we will instantiate later,
2659  // while we're still within our own instantiation context.
2660  SmallVector<VTableUse, 16> SavedVTableUses;
2661  std::deque<PendingImplicitInstantiation> SavedPendingInstantiations;
2662  if (Recursive) {
2663    VTableUses.swap(SavedVTableUses);
2664    PendingInstantiations.swap(SavedPendingInstantiations);
2665  }
2666
2667  // Enter the scope of this instantiation. We don't use
2668  // PushDeclContext because we don't have a scope.
2669  ContextRAII previousContext(*this, Var->getDeclContext());
2670
2671  VarDecl *OldVar = Var;
2672  Var = cast_or_null<VarDecl>(SubstDecl(Def, Var->getDeclContext(),
2673                                        getTemplateInstantiationArgs(Var)));
2674
2675  previousContext.pop();
2676
2677  if (Var) {
2678    MemberSpecializationInfo *MSInfo = OldVar->getMemberSpecializationInfo();
2679    assert(MSInfo && "Missing member specialization information?");
2680    Var->setTemplateSpecializationKind(MSInfo->getTemplateSpecializationKind(),
2681                                       MSInfo->getPointOfInstantiation());
2682    DeclGroupRef DG(Var);
2683    Consumer.HandleTopLevelDecl(DG);
2684  }
2685
2686  if (Recursive) {
2687    // Define any newly required vtables.
2688    DefineUsedVTables();
2689
2690    // Instantiate any pending implicit instantiations found during the
2691    // instantiation of this template.
2692    PerformPendingInstantiations();
2693
2694    // Restore the set of pending vtables.
2695    assert(VTableUses.empty() &&
2696           "VTableUses should be empty before it is discarded, "
2697           "while instantiating static data member.");
2698    VTableUses.swap(SavedVTableUses);
2699
2700    // Restore the set of pending implicit instantiations.
2701    assert(PendingInstantiations.empty() &&
2702           "PendingInstantiations should be empty before it is discarded, "
2703           "while instantiating static data member.");
2704    PendingInstantiations.swap(SavedPendingInstantiations);
2705  }
2706}
2707
2708static MultiInitializer CreateMultiInitializer(SmallVectorImpl<Expr*> &Args,
2709                                               const CXXCtorInitializer *Init) {
2710  // FIXME: This is a hack that will do slightly the wrong thing for an
2711  // initializer of the form foo({...}).
2712  // The right thing to do would be to modify InstantiateInitializer to create
2713  // the MultiInitializer.
2714  if (Args.size() == 1 && isa<InitListExpr>(Args[0]))
2715    return MultiInitializer(Args[0]);
2716  return MultiInitializer(Init->getLParenLoc(), Args.data(),
2717                          Args.size(), Init->getRParenLoc());
2718}
2719
2720void
2721Sema::InstantiateMemInitializers(CXXConstructorDecl *New,
2722                                 const CXXConstructorDecl *Tmpl,
2723                           const MultiLevelTemplateArgumentList &TemplateArgs) {
2724
2725  SmallVector<CXXCtorInitializer*, 4> NewInits;
2726  bool AnyErrors = false;
2727
2728  // Instantiate all the initializers.
2729  for (CXXConstructorDecl::init_const_iterator Inits = Tmpl->init_begin(),
2730                                            InitsEnd = Tmpl->init_end();
2731       Inits != InitsEnd; ++Inits) {
2732    CXXCtorInitializer *Init = *Inits;
2733
2734    // Only instantiate written initializers, let Sema re-construct implicit
2735    // ones.
2736    if (!Init->isWritten())
2737      continue;
2738
2739    SourceLocation LParenLoc, RParenLoc;
2740    ASTOwningVector<Expr*> NewArgs(*this);
2741
2742    SourceLocation EllipsisLoc;
2743
2744    if (Init->isPackExpansion()) {
2745      // This is a pack expansion. We should expand it now.
2746      TypeLoc BaseTL = Init->getBaseClassInfo()->getTypeLoc();
2747      SmallVector<UnexpandedParameterPack, 2> Unexpanded;
2748      collectUnexpandedParameterPacks(BaseTL, Unexpanded);
2749      bool ShouldExpand = false;
2750      bool RetainExpansion = false;
2751      llvm::Optional<unsigned> NumExpansions;
2752      if (CheckParameterPacksForExpansion(Init->getEllipsisLoc(),
2753                                          BaseTL.getSourceRange(),
2754                                          Unexpanded,
2755                                          TemplateArgs, ShouldExpand,
2756                                          RetainExpansion,
2757                                          NumExpansions)) {
2758        AnyErrors = true;
2759        New->setInvalidDecl();
2760        continue;
2761      }
2762      assert(ShouldExpand && "Partial instantiation of base initializer?");
2763
2764      // Loop over all of the arguments in the argument pack(s),
2765      for (unsigned I = 0; I != *NumExpansions; ++I) {
2766        Sema::ArgumentPackSubstitutionIndexRAII SubstIndex(*this, I);
2767
2768        // Instantiate the initializer.
2769        if (InstantiateInitializer(Init->getInit(), TemplateArgs,
2770                                   LParenLoc, NewArgs, RParenLoc)) {
2771          AnyErrors = true;
2772          break;
2773        }
2774
2775        // Instantiate the base type.
2776        TypeSourceInfo *BaseTInfo = SubstType(Init->getBaseClassInfo(),
2777                                              TemplateArgs,
2778                                              Init->getSourceLocation(),
2779                                              New->getDeclName());
2780        if (!BaseTInfo) {
2781          AnyErrors = true;
2782          break;
2783        }
2784
2785        // Build the initializer.
2786        MultiInitializer MultiInit(CreateMultiInitializer(NewArgs, Init));
2787        MemInitResult NewInit = BuildBaseInitializer(BaseTInfo->getType(),
2788                                                     BaseTInfo, MultiInit,
2789                                                     New->getParent(),
2790                                                     SourceLocation());
2791        if (NewInit.isInvalid()) {
2792          AnyErrors = true;
2793          break;
2794        }
2795
2796        NewInits.push_back(NewInit.get());
2797        NewArgs.clear();
2798      }
2799
2800      continue;
2801    }
2802
2803    // Instantiate the initializer.
2804    if (InstantiateInitializer(Init->getInit(), TemplateArgs,
2805                               LParenLoc, NewArgs, RParenLoc)) {
2806      AnyErrors = true;
2807      continue;
2808    }
2809
2810    MemInitResult NewInit;
2811    if (Init->isBaseInitializer()) {
2812      TypeSourceInfo *BaseTInfo = SubstType(Init->getBaseClassInfo(),
2813                                            TemplateArgs,
2814                                            Init->getSourceLocation(),
2815                                            New->getDeclName());
2816      if (!BaseTInfo) {
2817        AnyErrors = true;
2818        New->setInvalidDecl();
2819        continue;
2820      }
2821
2822      MultiInitializer MultiInit(CreateMultiInitializer(NewArgs, Init));
2823      NewInit = BuildBaseInitializer(BaseTInfo->getType(), BaseTInfo, MultiInit,
2824                                     New->getParent(), EllipsisLoc);
2825    } else if (Init->isMemberInitializer()) {
2826      FieldDecl *Member = cast_or_null<FieldDecl>(FindInstantiatedDecl(
2827                                                     Init->getMemberLocation(),
2828                                                     Init->getMember(),
2829                                                     TemplateArgs));
2830      if (!Member) {
2831        AnyErrors = true;
2832        New->setInvalidDecl();
2833        continue;
2834      }
2835
2836      MultiInitializer MultiInit(CreateMultiInitializer(NewArgs, Init));
2837      NewInit = BuildMemberInitializer(Member, MultiInit,
2838                                       Init->getSourceLocation());
2839    } else if (Init->isIndirectMemberInitializer()) {
2840      IndirectFieldDecl *IndirectMember =
2841         cast_or_null<IndirectFieldDecl>(FindInstantiatedDecl(
2842                                 Init->getMemberLocation(),
2843                                 Init->getIndirectMember(), TemplateArgs));
2844
2845      if (!IndirectMember) {
2846        AnyErrors = true;
2847        New->setInvalidDecl();
2848        continue;
2849      }
2850
2851      MultiInitializer MultiInit(CreateMultiInitializer(NewArgs, Init));
2852      NewInit = BuildMemberInitializer(IndirectMember, MultiInit,
2853                                       Init->getSourceLocation());
2854    }
2855
2856    if (NewInit.isInvalid()) {
2857      AnyErrors = true;
2858      New->setInvalidDecl();
2859    } else {
2860      // FIXME: It would be nice if ASTOwningVector had a release function.
2861      NewArgs.take();
2862
2863      NewInits.push_back(NewInit.get());
2864    }
2865  }
2866
2867  // Assign all the initializers to the new constructor.
2868  ActOnMemInitializers(New,
2869                       /*FIXME: ColonLoc */
2870                       SourceLocation(),
2871                       NewInits.data(), NewInits.size(),
2872                       AnyErrors);
2873}
2874
2875// TODO: this could be templated if the various decl types used the
2876// same method name.
2877static bool isInstantiationOf(ClassTemplateDecl *Pattern,
2878                              ClassTemplateDecl *Instance) {
2879  Pattern = Pattern->getCanonicalDecl();
2880
2881  do {
2882    Instance = Instance->getCanonicalDecl();
2883    if (Pattern == Instance) return true;
2884    Instance = Instance->getInstantiatedFromMemberTemplate();
2885  } while (Instance);
2886
2887  return false;
2888}
2889
2890static bool isInstantiationOf(FunctionTemplateDecl *Pattern,
2891                              FunctionTemplateDecl *Instance) {
2892  Pattern = Pattern->getCanonicalDecl();
2893
2894  do {
2895    Instance = Instance->getCanonicalDecl();
2896    if (Pattern == Instance) return true;
2897    Instance = Instance->getInstantiatedFromMemberTemplate();
2898  } while (Instance);
2899
2900  return false;
2901}
2902
2903static bool
2904isInstantiationOf(ClassTemplatePartialSpecializationDecl *Pattern,
2905                  ClassTemplatePartialSpecializationDecl *Instance) {
2906  Pattern
2907    = cast<ClassTemplatePartialSpecializationDecl>(Pattern->getCanonicalDecl());
2908  do {
2909    Instance = cast<ClassTemplatePartialSpecializationDecl>(
2910                                                Instance->getCanonicalDecl());
2911    if (Pattern == Instance)
2912      return true;
2913    Instance = Instance->getInstantiatedFromMember();
2914  } while (Instance);
2915
2916  return false;
2917}
2918
2919static bool isInstantiationOf(CXXRecordDecl *Pattern,
2920                              CXXRecordDecl *Instance) {
2921  Pattern = Pattern->getCanonicalDecl();
2922
2923  do {
2924    Instance = Instance->getCanonicalDecl();
2925    if (Pattern == Instance) return true;
2926    Instance = Instance->getInstantiatedFromMemberClass();
2927  } while (Instance);
2928
2929  return false;
2930}
2931
2932static bool isInstantiationOf(FunctionDecl *Pattern,
2933                              FunctionDecl *Instance) {
2934  Pattern = Pattern->getCanonicalDecl();
2935
2936  do {
2937    Instance = Instance->getCanonicalDecl();
2938    if (Pattern == Instance) return true;
2939    Instance = Instance->getInstantiatedFromMemberFunction();
2940  } while (Instance);
2941
2942  return false;
2943}
2944
2945static bool isInstantiationOf(EnumDecl *Pattern,
2946                              EnumDecl *Instance) {
2947  Pattern = Pattern->getCanonicalDecl();
2948
2949  do {
2950    Instance = Instance->getCanonicalDecl();
2951    if (Pattern == Instance) return true;
2952    Instance = Instance->getInstantiatedFromMemberEnum();
2953  } while (Instance);
2954
2955  return false;
2956}
2957
2958static bool isInstantiationOf(UsingShadowDecl *Pattern,
2959                              UsingShadowDecl *Instance,
2960                              ASTContext &C) {
2961  return C.getInstantiatedFromUsingShadowDecl(Instance) == Pattern;
2962}
2963
2964static bool isInstantiationOf(UsingDecl *Pattern,
2965                              UsingDecl *Instance,
2966                              ASTContext &C) {
2967  return C.getInstantiatedFromUsingDecl(Instance) == Pattern;
2968}
2969
2970static bool isInstantiationOf(UnresolvedUsingValueDecl *Pattern,
2971                              UsingDecl *Instance,
2972                              ASTContext &C) {
2973  return C.getInstantiatedFromUsingDecl(Instance) == Pattern;
2974}
2975
2976static bool isInstantiationOf(UnresolvedUsingTypenameDecl *Pattern,
2977                              UsingDecl *Instance,
2978                              ASTContext &C) {
2979  return C.getInstantiatedFromUsingDecl(Instance) == Pattern;
2980}
2981
2982static bool isInstantiationOfStaticDataMember(VarDecl *Pattern,
2983                                              VarDecl *Instance) {
2984  assert(Instance->isStaticDataMember());
2985
2986  Pattern = Pattern->getCanonicalDecl();
2987
2988  do {
2989    Instance = Instance->getCanonicalDecl();
2990    if (Pattern == Instance) return true;
2991    Instance = Instance->getInstantiatedFromStaticDataMember();
2992  } while (Instance);
2993
2994  return false;
2995}
2996
2997// Other is the prospective instantiation
2998// D is the prospective pattern
2999static bool isInstantiationOf(ASTContext &Ctx, NamedDecl *D, Decl *Other) {
3000  if (D->getKind() != Other->getKind()) {
3001    if (UnresolvedUsingTypenameDecl *UUD
3002          = dyn_cast<UnresolvedUsingTypenameDecl>(D)) {
3003      if (UsingDecl *UD = dyn_cast<UsingDecl>(Other)) {
3004        return isInstantiationOf(UUD, UD, Ctx);
3005      }
3006    }
3007
3008    if (UnresolvedUsingValueDecl *UUD
3009          = dyn_cast<UnresolvedUsingValueDecl>(D)) {
3010      if (UsingDecl *UD = dyn_cast<UsingDecl>(Other)) {
3011        return isInstantiationOf(UUD, UD, Ctx);
3012      }
3013    }
3014
3015    return false;
3016  }
3017
3018  if (CXXRecordDecl *Record = dyn_cast<CXXRecordDecl>(Other))
3019    return isInstantiationOf(cast<CXXRecordDecl>(D), Record);
3020
3021  if (FunctionDecl *Function = dyn_cast<FunctionDecl>(Other))
3022    return isInstantiationOf(cast<FunctionDecl>(D), Function);
3023
3024  if (EnumDecl *Enum = dyn_cast<EnumDecl>(Other))
3025    return isInstantiationOf(cast<EnumDecl>(D), Enum);
3026
3027  if (VarDecl *Var = dyn_cast<VarDecl>(Other))
3028    if (Var->isStaticDataMember())
3029      return isInstantiationOfStaticDataMember(cast<VarDecl>(D), Var);
3030
3031  if (ClassTemplateDecl *Temp = dyn_cast<ClassTemplateDecl>(Other))
3032    return isInstantiationOf(cast<ClassTemplateDecl>(D), Temp);
3033
3034  if (FunctionTemplateDecl *Temp = dyn_cast<FunctionTemplateDecl>(Other))
3035    return isInstantiationOf(cast<FunctionTemplateDecl>(D), Temp);
3036
3037  if (ClassTemplatePartialSpecializationDecl *PartialSpec
3038        = dyn_cast<ClassTemplatePartialSpecializationDecl>(Other))
3039    return isInstantiationOf(cast<ClassTemplatePartialSpecializationDecl>(D),
3040                             PartialSpec);
3041
3042  if (FieldDecl *Field = dyn_cast<FieldDecl>(Other)) {
3043    if (!Field->getDeclName()) {
3044      // This is an unnamed field.
3045      return Ctx.getInstantiatedFromUnnamedFieldDecl(Field) ==
3046        cast<FieldDecl>(D);
3047    }
3048  }
3049
3050  if (UsingDecl *Using = dyn_cast<UsingDecl>(Other))
3051    return isInstantiationOf(cast<UsingDecl>(D), Using, Ctx);
3052
3053  if (UsingShadowDecl *Shadow = dyn_cast<UsingShadowDecl>(Other))
3054    return isInstantiationOf(cast<UsingShadowDecl>(D), Shadow, Ctx);
3055
3056  return D->getDeclName() && isa<NamedDecl>(Other) &&
3057    D->getDeclName() == cast<NamedDecl>(Other)->getDeclName();
3058}
3059
3060template<typename ForwardIterator>
3061static NamedDecl *findInstantiationOf(ASTContext &Ctx,
3062                                      NamedDecl *D,
3063                                      ForwardIterator first,
3064                                      ForwardIterator last) {
3065  for (; first != last; ++first)
3066    if (isInstantiationOf(Ctx, D, *first))
3067      return cast<NamedDecl>(*first);
3068
3069  return 0;
3070}
3071
3072/// \brief Finds the instantiation of the given declaration context
3073/// within the current instantiation.
3074///
3075/// \returns NULL if there was an error
3076DeclContext *Sema::FindInstantiatedContext(SourceLocation Loc, DeclContext* DC,
3077                          const MultiLevelTemplateArgumentList &TemplateArgs) {
3078  if (NamedDecl *D = dyn_cast<NamedDecl>(DC)) {
3079    Decl* ID = FindInstantiatedDecl(Loc, D, TemplateArgs);
3080    return cast_or_null<DeclContext>(ID);
3081  } else return DC;
3082}
3083
3084/// \brief Find the instantiation of the given declaration within the
3085/// current instantiation.
3086///
3087/// This routine is intended to be used when \p D is a declaration
3088/// referenced from within a template, that needs to mapped into the
3089/// corresponding declaration within an instantiation. For example,
3090/// given:
3091///
3092/// \code
3093/// template<typename T>
3094/// struct X {
3095///   enum Kind {
3096///     KnownValue = sizeof(T)
3097///   };
3098///
3099///   bool getKind() const { return KnownValue; }
3100/// };
3101///
3102/// template struct X<int>;
3103/// \endcode
3104///
3105/// In the instantiation of X<int>::getKind(), we need to map the
3106/// EnumConstantDecl for KnownValue (which refers to
3107/// X<T>::<Kind>::KnownValue) to its instantiation
3108/// (X<int>::<Kind>::KnownValue). InstantiateCurrentDeclRef() performs
3109/// this mapping from within the instantiation of X<int>.
3110NamedDecl *Sema::FindInstantiatedDecl(SourceLocation Loc, NamedDecl *D,
3111                          const MultiLevelTemplateArgumentList &TemplateArgs) {
3112  DeclContext *ParentDC = D->getDeclContext();
3113  if (isa<ParmVarDecl>(D) || isa<NonTypeTemplateParmDecl>(D) ||
3114      isa<TemplateTypeParmDecl>(D) || isa<TemplateTemplateParmDecl>(D) ||
3115      (ParentDC->isFunctionOrMethod() && ParentDC->isDependentContext())) {
3116    // D is a local of some kind. Look into the map of local
3117    // declarations to their instantiations.
3118    typedef LocalInstantiationScope::DeclArgumentPack DeclArgumentPack;
3119    llvm::PointerUnion<Decl *, DeclArgumentPack *> *Found
3120      = CurrentInstantiationScope->findInstantiationOf(D);
3121
3122    if (Found) {
3123      if (Decl *FD = Found->dyn_cast<Decl *>())
3124        return cast<NamedDecl>(FD);
3125
3126      unsigned PackIdx = ArgumentPackSubstitutionIndex;
3127      return cast<NamedDecl>((*Found->get<DeclArgumentPack *>())[PackIdx]);
3128    }
3129
3130    // If we didn't find the decl, then we must have a label decl that hasn't
3131    // been found yet.  Lazily instantiate it and return it now.
3132    assert(isa<LabelDecl>(D));
3133
3134    Decl *Inst = SubstDecl(D, CurContext, TemplateArgs);
3135    assert(Inst && "Failed to instantiate label??");
3136
3137    CurrentInstantiationScope->InstantiatedLocal(D, Inst);
3138    return cast<LabelDecl>(Inst);
3139  }
3140
3141  if (CXXRecordDecl *Record = dyn_cast<CXXRecordDecl>(D)) {
3142    if (!Record->isDependentContext())
3143      return D;
3144
3145    // If the RecordDecl is actually the injected-class-name or a
3146    // "templated" declaration for a class template, class template
3147    // partial specialization, or a member class of a class template,
3148    // substitute into the injected-class-name of the class template
3149    // or partial specialization to find the new DeclContext.
3150    QualType T;
3151    ClassTemplateDecl *ClassTemplate = Record->getDescribedClassTemplate();
3152
3153    if (ClassTemplate) {
3154      T = ClassTemplate->getInjectedClassNameSpecialization();
3155    } else if (ClassTemplatePartialSpecializationDecl *PartialSpec
3156                 = dyn_cast<ClassTemplatePartialSpecializationDecl>(Record)) {
3157      ClassTemplate = PartialSpec->getSpecializedTemplate();
3158
3159      // If we call SubstType with an InjectedClassNameType here we
3160      // can end up in an infinite loop.
3161      T = Context.getTypeDeclType(Record);
3162      assert(isa<InjectedClassNameType>(T) &&
3163             "type of partial specialization is not an InjectedClassNameType");
3164      T = cast<InjectedClassNameType>(T)->getInjectedSpecializationType();
3165    }
3166
3167    if (!T.isNull()) {
3168      // Substitute into the injected-class-name to get the type
3169      // corresponding to the instantiation we want, which may also be
3170      // the current instantiation (if we're in a template
3171      // definition). This substitution should never fail, since we
3172      // know we can instantiate the injected-class-name or we
3173      // wouldn't have gotten to the injected-class-name!
3174
3175      // FIXME: Can we use the CurrentInstantiationScope to avoid this
3176      // extra instantiation in the common case?
3177      T = SubstType(T, TemplateArgs, Loc, DeclarationName());
3178      assert(!T.isNull() && "Instantiation of injected-class-name cannot fail.");
3179
3180      if (!T->isDependentType()) {
3181        assert(T->isRecordType() && "Instantiation must produce a record type");
3182        return T->getAs<RecordType>()->getDecl();
3183      }
3184
3185      // We are performing "partial" template instantiation to create
3186      // the member declarations for the members of a class template
3187      // specialization. Therefore, D is actually referring to something
3188      // in the current instantiation. Look through the current
3189      // context, which contains actual instantiations, to find the
3190      // instantiation of the "current instantiation" that D refers
3191      // to.
3192      bool SawNonDependentContext = false;
3193      for (DeclContext *DC = CurContext; !DC->isFileContext();
3194           DC = DC->getParent()) {
3195        if (ClassTemplateSpecializationDecl *Spec
3196                          = dyn_cast<ClassTemplateSpecializationDecl>(DC))
3197          if (isInstantiationOf(ClassTemplate,
3198                                Spec->getSpecializedTemplate()))
3199            return Spec;
3200
3201        if (!DC->isDependentContext())
3202          SawNonDependentContext = true;
3203      }
3204
3205      // We're performing "instantiation" of a member of the current
3206      // instantiation while we are type-checking the
3207      // definition. Compute the declaration context and return that.
3208      assert(!SawNonDependentContext &&
3209             "No dependent context while instantiating record");
3210      DeclContext *DC = computeDeclContext(T);
3211      assert(DC &&
3212             "Unable to find declaration for the current instantiation");
3213      return cast<CXXRecordDecl>(DC);
3214    }
3215
3216    // Fall through to deal with other dependent record types (e.g.,
3217    // anonymous unions in class templates).
3218  }
3219
3220  if (!ParentDC->isDependentContext())
3221    return D;
3222
3223  ParentDC = FindInstantiatedContext(Loc, ParentDC, TemplateArgs);
3224  if (!ParentDC)
3225    return 0;
3226
3227  if (ParentDC != D->getDeclContext()) {
3228    // We performed some kind of instantiation in the parent context,
3229    // so now we need to look into the instantiated parent context to
3230    // find the instantiation of the declaration D.
3231
3232    // If our context used to be dependent, we may need to instantiate
3233    // it before performing lookup into that context.
3234    bool IsBeingInstantiated = false;
3235    if (CXXRecordDecl *Spec = dyn_cast<CXXRecordDecl>(ParentDC)) {
3236      if (!Spec->isDependentContext()) {
3237        QualType T = Context.getTypeDeclType(Spec);
3238        const RecordType *Tag = T->getAs<RecordType>();
3239        assert(Tag && "type of non-dependent record is not a RecordType");
3240        if (Tag->isBeingDefined())
3241          IsBeingInstantiated = true;
3242        if (!Tag->isBeingDefined() &&
3243            RequireCompleteType(Loc, T, diag::err_incomplete_type))
3244          return 0;
3245
3246        ParentDC = Tag->getDecl();
3247      }
3248    }
3249
3250    NamedDecl *Result = 0;
3251    if (D->getDeclName()) {
3252      DeclContext::lookup_result Found = ParentDC->lookup(D->getDeclName());
3253      Result = findInstantiationOf(Context, D, Found.first, Found.second);
3254    } else {
3255      // Since we don't have a name for the entity we're looking for,
3256      // our only option is to walk through all of the declarations to
3257      // find that name. This will occur in a few cases:
3258      //
3259      //   - anonymous struct/union within a template
3260      //   - unnamed class/struct/union/enum within a template
3261      //
3262      // FIXME: Find a better way to find these instantiations!
3263      Result = findInstantiationOf(Context, D,
3264                                   ParentDC->decls_begin(),
3265                                   ParentDC->decls_end());
3266    }
3267
3268    if (!Result) {
3269      if (isa<UsingShadowDecl>(D)) {
3270        // UsingShadowDecls can instantiate to nothing because of using hiding.
3271      } else if (Diags.hasErrorOccurred()) {
3272        // We've already complained about something, so most likely this
3273        // declaration failed to instantiate. There's no point in complaining
3274        // further, since this is normal in invalid code.
3275      } else if (IsBeingInstantiated) {
3276        // The class in which this member exists is currently being
3277        // instantiated, and we haven't gotten around to instantiating this
3278        // member yet. This can happen when the code uses forward declarations
3279        // of member classes, and introduces ordering dependencies via
3280        // template instantiation.
3281        Diag(Loc, diag::err_member_not_yet_instantiated)
3282          << D->getDeclName()
3283          << Context.getTypeDeclType(cast<CXXRecordDecl>(ParentDC));
3284        Diag(D->getLocation(), diag::note_non_instantiated_member_here);
3285      } else {
3286        // We should have found something, but didn't.
3287        llvm_unreachable("Unable to find instantiation of declaration!");
3288      }
3289    }
3290
3291    D = Result;
3292  }
3293
3294  return D;
3295}
3296
3297/// \brief Performs template instantiation for all implicit template
3298/// instantiations we have seen until this point.
3299void Sema::PerformPendingInstantiations(bool LocalOnly) {
3300  // Load pending instantiations from the external source.
3301  if (!LocalOnly && ExternalSource) {
3302    SmallVector<std::pair<ValueDecl *, SourceLocation>, 4> Pending;
3303    ExternalSource->ReadPendingInstantiations(Pending);
3304    PendingInstantiations.insert(PendingInstantiations.begin(),
3305                                 Pending.begin(), Pending.end());
3306  }
3307
3308  while (!PendingLocalImplicitInstantiations.empty() ||
3309         (!LocalOnly && !PendingInstantiations.empty())) {
3310    PendingImplicitInstantiation Inst;
3311
3312    if (PendingLocalImplicitInstantiations.empty()) {
3313      Inst = PendingInstantiations.front();
3314      PendingInstantiations.pop_front();
3315    } else {
3316      Inst = PendingLocalImplicitInstantiations.front();
3317      PendingLocalImplicitInstantiations.pop_front();
3318    }
3319
3320    // Instantiate function definitions
3321    if (FunctionDecl *Function = dyn_cast<FunctionDecl>(Inst.first)) {
3322      PrettyDeclStackTraceEntry CrashInfo(*this, Function, SourceLocation(),
3323                                          "instantiating function definition");
3324      bool DefinitionRequired = Function->getTemplateSpecializationKind() ==
3325                                TSK_ExplicitInstantiationDefinition;
3326      InstantiateFunctionDefinition(/*FIXME:*/Inst.second, Function, true,
3327                                    DefinitionRequired);
3328      continue;
3329    }
3330
3331    // Instantiate static data member definitions.
3332    VarDecl *Var = cast<VarDecl>(Inst.first);
3333    assert(Var->isStaticDataMember() && "Not a static data member?");
3334
3335    // Don't try to instantiate declarations if the most recent redeclaration
3336    // is invalid.
3337    if (Var->getMostRecentDeclaration()->isInvalidDecl())
3338      continue;
3339
3340    // Check if the most recent declaration has changed the specialization kind
3341    // and removed the need for implicit instantiation.
3342    switch (Var->getMostRecentDeclaration()->getTemplateSpecializationKind()) {
3343    case TSK_Undeclared:
3344      llvm_unreachable("Cannot instantitiate an undeclared specialization.");
3345    case TSK_ExplicitInstantiationDeclaration:
3346    case TSK_ExplicitSpecialization:
3347      continue;  // No longer need to instantiate this type.
3348    case TSK_ExplicitInstantiationDefinition:
3349      // We only need an instantiation if the pending instantiation *is* the
3350      // explicit instantiation.
3351      if (Var != Var->getMostRecentDeclaration()) continue;
3352    case TSK_ImplicitInstantiation:
3353      break;
3354    }
3355
3356    PrettyDeclStackTraceEntry CrashInfo(*this, Var, Var->getLocation(),
3357                                        "instantiating static data member "
3358                                        "definition");
3359
3360    bool DefinitionRequired = Var->getTemplateSpecializationKind() ==
3361                              TSK_ExplicitInstantiationDefinition;
3362    InstantiateStaticDataMemberDefinition(/*FIXME:*/Inst.second, Var, true,
3363                                          DefinitionRequired);
3364  }
3365}
3366
3367void Sema::PerformDependentDiagnostics(const DeclContext *Pattern,
3368                       const MultiLevelTemplateArgumentList &TemplateArgs) {
3369  for (DeclContext::ddiag_iterator I = Pattern->ddiag_begin(),
3370         E = Pattern->ddiag_end(); I != E; ++I) {
3371    DependentDiagnostic *DD = *I;
3372
3373    switch (DD->getKind()) {
3374    case DependentDiagnostic::Access:
3375      HandleDependentAccessCheck(*DD, TemplateArgs);
3376      break;
3377    }
3378  }
3379}
3380