SemaTemplateInstantiateDecl.cpp revision 76852c218a207ef43583515cb835b6e855353a0f 
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->getLocation(),
556                                                 D->getFriendLoc(), InstTy);
557    if (!FD)
558      return 0;
559
560    FD->setAccess(AS_public);
561    FD->setUnsupportedFriend(D->isUnsupportedFriend());
562    Owner->addDecl(FD);
563    return FD;
564  }
565
566  NamedDecl *ND = D->getFriendDecl();
567  assert(ND && "friend decl must be a decl or a type!");
568
569  // All of the Visit implementations for the various potential friend
570  // declarations have to be carefully written to work for friend
571  // objects, with the most important detail being that the target
572  // decl should almost certainly not be placed in Owner.
573  Decl *NewND = Visit(ND);
574  if (!NewND) return 0;
575
576  FriendDecl *FD =
577    FriendDecl::Create(SemaRef.Context, Owner, D->getLocation(),
578                       cast<NamedDecl>(NewND), D->getFriendLoc());
579  FD->setAccess(AS_public);
580  FD->setUnsupportedFriend(D->isUnsupportedFriend());
581  Owner->addDecl(FD);
582  return FD;
583}
584
585Decl *TemplateDeclInstantiator::VisitStaticAssertDecl(StaticAssertDecl *D) {
586  Expr *AssertExpr = D->getAssertExpr();
587
588  // The expression in a static assertion is not potentially evaluated.
589  EnterExpressionEvaluationContext Unevaluated(SemaRef, Sema::Unevaluated);
590
591  ExprResult InstantiatedAssertExpr
592    = SemaRef.SubstExpr(AssertExpr, TemplateArgs);
593  if (InstantiatedAssertExpr.isInvalid())
594    return 0;
595
596  ExprResult Message(D->getMessage());
597  D->getMessage();
598  return SemaRef.ActOnStaticAssertDeclaration(D->getLocation(),
599                                              InstantiatedAssertExpr.get(),
600                                              Message.get(),
601                                              D->getRParenLoc());
602}
603
604Decl *TemplateDeclInstantiator::VisitEnumDecl(EnumDecl *D) {
605  EnumDecl *Enum = EnumDecl::Create(SemaRef.Context, Owner, D->getLocStart(),
606                                    D->getLocation(), D->getIdentifier(),
607                                    /*PrevDecl=*/0, D->isScoped(),
608                                    D->isScopedUsingClassTag(), D->isFixed());
609  if (D->isFixed()) {
610    if (TypeSourceInfo* TI = D->getIntegerTypeSourceInfo()) {
611      // If we have type source information for the underlying type, it means it
612      // has been explicitly set by the user. Perform substitution on it before
613      // moving on.
614      SourceLocation UnderlyingLoc = TI->getTypeLoc().getBeginLoc();
615      Enum->setIntegerTypeSourceInfo(SemaRef.SubstType(TI,
616                                                       TemplateArgs,
617                                                       UnderlyingLoc,
618                                                       DeclarationName()));
619
620      if (!Enum->getIntegerTypeSourceInfo())
621        Enum->setIntegerType(SemaRef.Context.IntTy);
622    }
623    else {
624      assert(!D->getIntegerType()->isDependentType()
625             && "Dependent type without type source info");
626      Enum->setIntegerType(D->getIntegerType());
627    }
628  }
629
630  SemaRef.InstantiateAttrs(TemplateArgs, D, Enum);
631
632  Enum->setInstantiationOfMemberEnum(D);
633  Enum->setAccess(D->getAccess());
634  if (SubstQualifier(D, Enum)) return 0;
635  Owner->addDecl(Enum);
636  Enum->startDefinition();
637
638  if (D->getDeclContext()->isFunctionOrMethod())
639    SemaRef.CurrentInstantiationScope->InstantiatedLocal(D, Enum);
640
641  SmallVector<Decl*, 4> Enumerators;
642
643  EnumConstantDecl *LastEnumConst = 0;
644  for (EnumDecl::enumerator_iterator EC = D->enumerator_begin(),
645         ECEnd = D->enumerator_end();
646       EC != ECEnd; ++EC) {
647    // The specified value for the enumerator.
648    ExprResult Value = SemaRef.Owned((Expr *)0);
649    if (Expr *UninstValue = EC->getInitExpr()) {
650      // The enumerator's value expression is not potentially evaluated.
651      EnterExpressionEvaluationContext Unevaluated(SemaRef,
652                                                   Sema::Unevaluated);
653
654      Value = SemaRef.SubstExpr(UninstValue, TemplateArgs);
655    }
656
657    // Drop the initial value and continue.
658    bool isInvalid = false;
659    if (Value.isInvalid()) {
660      Value = SemaRef.Owned((Expr *)0);
661      isInvalid = true;
662    }
663
664    EnumConstantDecl *EnumConst
665      = SemaRef.CheckEnumConstant(Enum, LastEnumConst,
666                                  EC->getLocation(), EC->getIdentifier(),
667                                  Value.get());
668
669    if (isInvalid) {
670      if (EnumConst)
671        EnumConst->setInvalidDecl();
672      Enum->setInvalidDecl();
673    }
674
675    if (EnumConst) {
676      SemaRef.InstantiateAttrs(TemplateArgs, *EC, EnumConst);
677
678      EnumConst->setAccess(Enum->getAccess());
679      Enum->addDecl(EnumConst);
680      Enumerators.push_back(EnumConst);
681      LastEnumConst = EnumConst;
682
683      if (D->getDeclContext()->isFunctionOrMethod()) {
684        // If the enumeration is within a function or method, record the enum
685        // constant as a local.
686        SemaRef.CurrentInstantiationScope->InstantiatedLocal(*EC, EnumConst);
687      }
688    }
689  }
690
691  // FIXME: Fixup LBraceLoc and RBraceLoc
692  // FIXME: Empty Scope and AttributeList (required to handle attribute packed).
693  SemaRef.ActOnEnumBody(Enum->getLocation(), SourceLocation(), SourceLocation(),
694                        Enum,
695                        Enumerators.data(), Enumerators.size(),
696                        0, 0);
697
698  return Enum;
699}
700
701Decl *TemplateDeclInstantiator::VisitEnumConstantDecl(EnumConstantDecl *D) {
702  llvm_unreachable("EnumConstantDecls can only occur within EnumDecls.");
703}
704
705Decl *TemplateDeclInstantiator::VisitClassTemplateDecl(ClassTemplateDecl *D) {
706  bool isFriend = (D->getFriendObjectKind() != Decl::FOK_None);
707
708  // Create a local instantiation scope for this class template, which
709  // will contain the instantiations of the template parameters.
710  LocalInstantiationScope Scope(SemaRef);
711  TemplateParameterList *TempParams = D->getTemplateParameters();
712  TemplateParameterList *InstParams = SubstTemplateParams(TempParams);
713  if (!InstParams)
714    return NULL;
715
716  CXXRecordDecl *Pattern = D->getTemplatedDecl();
717
718  // Instantiate the qualifier.  We have to do this first in case
719  // we're a friend declaration, because if we are then we need to put
720  // the new declaration in the appropriate context.
721  NestedNameSpecifierLoc QualifierLoc = Pattern->getQualifierLoc();
722  if (QualifierLoc) {
723    QualifierLoc = SemaRef.SubstNestedNameSpecifierLoc(QualifierLoc,
724                                                       TemplateArgs);
725    if (!QualifierLoc)
726      return 0;
727  }
728
729  CXXRecordDecl *PrevDecl = 0;
730  ClassTemplateDecl *PrevClassTemplate = 0;
731
732  if (!isFriend && Pattern->getPreviousDeclaration()) {
733    DeclContext::lookup_result Found = Owner->lookup(Pattern->getDeclName());
734    if (Found.first != Found.second) {
735      PrevClassTemplate = dyn_cast<ClassTemplateDecl>(*Found.first);
736      if (PrevClassTemplate)
737        PrevDecl = PrevClassTemplate->getTemplatedDecl();
738    }
739  }
740
741  // If this isn't a friend, then it's a member template, in which
742  // case we just want to build the instantiation in the
743  // specialization.  If it is a friend, we want to build it in
744  // the appropriate context.
745  DeclContext *DC = Owner;
746  if (isFriend) {
747    if (QualifierLoc) {
748      CXXScopeSpec SS;
749      SS.Adopt(QualifierLoc);
750      DC = SemaRef.computeDeclContext(SS);
751      if (!DC) return 0;
752    } else {
753      DC = SemaRef.FindInstantiatedContext(Pattern->getLocation(),
754                                           Pattern->getDeclContext(),
755                                           TemplateArgs);
756    }
757
758    // Look for a previous declaration of the template in the owning
759    // context.
760    LookupResult R(SemaRef, Pattern->getDeclName(), Pattern->getLocation(),
761                   Sema::LookupOrdinaryName, Sema::ForRedeclaration);
762    SemaRef.LookupQualifiedName(R, DC);
763
764    if (R.isSingleResult()) {
765      PrevClassTemplate = R.getAsSingle<ClassTemplateDecl>();
766      if (PrevClassTemplate)
767        PrevDecl = PrevClassTemplate->getTemplatedDecl();
768    }
769
770    if (!PrevClassTemplate && QualifierLoc) {
771      SemaRef.Diag(Pattern->getLocation(), diag::err_not_tag_in_scope)
772        << D->getTemplatedDecl()->getTagKind() << Pattern->getDeclName() << DC
773        << QualifierLoc.getSourceRange();
774      return 0;
775    }
776
777    bool AdoptedPreviousTemplateParams = false;
778    if (PrevClassTemplate) {
779      bool Complain = true;
780
781      // HACK: libstdc++ 4.2.1 contains an ill-formed friend class
782      // template for struct std::tr1::__detail::_Map_base, where the
783      // template parameters of the friend declaration don't match the
784      // template parameters of the original declaration. In this one
785      // case, we don't complain about the ill-formed friend
786      // declaration.
787      if (isFriend && Pattern->getIdentifier() &&
788          Pattern->getIdentifier()->isStr("_Map_base") &&
789          DC->isNamespace() &&
790          cast<NamespaceDecl>(DC)->getIdentifier() &&
791          cast<NamespaceDecl>(DC)->getIdentifier()->isStr("__detail")) {
792        DeclContext *DCParent = DC->getParent();
793        if (DCParent->isNamespace() &&
794            cast<NamespaceDecl>(DCParent)->getIdentifier() &&
795            cast<NamespaceDecl>(DCParent)->getIdentifier()->isStr("tr1")) {
796          DeclContext *DCParent2 = DCParent->getParent();
797          if (DCParent2->isNamespace() &&
798              cast<NamespaceDecl>(DCParent2)->getIdentifier() &&
799              cast<NamespaceDecl>(DCParent2)->getIdentifier()->isStr("std") &&
800              DCParent2->getParent()->isTranslationUnit())
801            Complain = false;
802        }
803      }
804
805      TemplateParameterList *PrevParams
806        = PrevClassTemplate->getTemplateParameters();
807
808      // Make sure the parameter lists match.
809      if (!SemaRef.TemplateParameterListsAreEqual(InstParams, PrevParams,
810                                                  Complain,
811                                                  Sema::TPL_TemplateMatch)) {
812        if (Complain)
813          return 0;
814
815        AdoptedPreviousTemplateParams = true;
816        InstParams = PrevParams;
817      }
818
819      // Do some additional validation, then merge default arguments
820      // from the existing declarations.
821      if (!AdoptedPreviousTemplateParams &&
822          SemaRef.CheckTemplateParameterList(InstParams, PrevParams,
823                                             Sema::TPC_ClassTemplate))
824        return 0;
825    }
826  }
827
828  CXXRecordDecl *RecordInst
829    = CXXRecordDecl::Create(SemaRef.Context, Pattern->getTagKind(), DC,
830                            Pattern->getLocStart(), Pattern->getLocation(),
831                            Pattern->getIdentifier(), PrevDecl,
832                            /*DelayTypeCreation=*/true);
833
834  if (QualifierLoc)
835    RecordInst->setQualifierInfo(QualifierLoc);
836
837  ClassTemplateDecl *Inst
838    = ClassTemplateDecl::Create(SemaRef.Context, DC, D->getLocation(),
839                                D->getIdentifier(), InstParams, RecordInst,
840                                PrevClassTemplate);
841  RecordInst->setDescribedClassTemplate(Inst);
842
843  if (isFriend) {
844    if (PrevClassTemplate)
845      Inst->setAccess(PrevClassTemplate->getAccess());
846    else
847      Inst->setAccess(D->getAccess());
848
849    Inst->setObjectOfFriendDecl(PrevClassTemplate != 0);
850    // TODO: do we want to track the instantiation progeny of this
851    // friend target decl?
852  } else {
853    Inst->setAccess(D->getAccess());
854    if (!PrevClassTemplate)
855      Inst->setInstantiatedFromMemberTemplate(D);
856  }
857
858  // Trigger creation of the type for the instantiation.
859  SemaRef.Context.getInjectedClassNameType(RecordInst,
860                                    Inst->getInjectedClassNameSpecialization());
861
862  // Finish handling of friends.
863  if (isFriend) {
864    DC->makeDeclVisibleInContext(Inst, /*Recoverable*/ false);
865    return Inst;
866  }
867
868  Owner->addDecl(Inst);
869
870  if (!PrevClassTemplate) {
871    // Queue up any out-of-line partial specializations of this member
872    // class template; the client will force their instantiation once
873    // the enclosing class has been instantiated.
874    SmallVector<ClassTemplatePartialSpecializationDecl *, 4> PartialSpecs;
875    D->getPartialSpecializations(PartialSpecs);
876    for (unsigned I = 0, N = PartialSpecs.size(); I != N; ++I)
877      if (PartialSpecs[I]->isOutOfLine())
878        OutOfLinePartialSpecs.push_back(std::make_pair(Inst, PartialSpecs[I]));
879  }
880
881  return Inst;
882}
883
884Decl *
885TemplateDeclInstantiator::VisitClassTemplatePartialSpecializationDecl(
886                                   ClassTemplatePartialSpecializationDecl *D) {
887  ClassTemplateDecl *ClassTemplate = D->getSpecializedTemplate();
888
889  // Lookup the already-instantiated declaration in the instantiation
890  // of the class template and return that.
891  DeclContext::lookup_result Found
892    = Owner->lookup(ClassTemplate->getDeclName());
893  if (Found.first == Found.second)
894    return 0;
895
896  ClassTemplateDecl *InstClassTemplate
897    = dyn_cast<ClassTemplateDecl>(*Found.first);
898  if (!InstClassTemplate)
899    return 0;
900
901  if (ClassTemplatePartialSpecializationDecl *Result
902        = InstClassTemplate->findPartialSpecInstantiatedFromMember(D))
903    return Result;
904
905  return InstantiateClassTemplatePartialSpecialization(InstClassTemplate, D);
906}
907
908Decl *
909TemplateDeclInstantiator::VisitFunctionTemplateDecl(FunctionTemplateDecl *D) {
910  // Create a local instantiation scope for this function template, which
911  // will contain the instantiations of the template parameters and then get
912  // merged with the local instantiation scope for the function template
913  // itself.
914  LocalInstantiationScope Scope(SemaRef);
915
916  TemplateParameterList *TempParams = D->getTemplateParameters();
917  TemplateParameterList *InstParams = SubstTemplateParams(TempParams);
918  if (!InstParams)
919    return NULL;
920
921  FunctionDecl *Instantiated = 0;
922  if (CXXMethodDecl *DMethod = dyn_cast<CXXMethodDecl>(D->getTemplatedDecl()))
923    Instantiated = cast_or_null<FunctionDecl>(VisitCXXMethodDecl(DMethod,
924                                                                 InstParams));
925  else
926    Instantiated = cast_or_null<FunctionDecl>(VisitFunctionDecl(
927                                                          D->getTemplatedDecl(),
928                                                                InstParams));
929
930  if (!Instantiated)
931    return 0;
932
933  Instantiated->setAccess(D->getAccess());
934
935  // Link the instantiated function template declaration to the function
936  // template from which it was instantiated.
937  FunctionTemplateDecl *InstTemplate
938    = Instantiated->getDescribedFunctionTemplate();
939  InstTemplate->setAccess(D->getAccess());
940  assert(InstTemplate &&
941         "VisitFunctionDecl/CXXMethodDecl didn't create a template!");
942
943  bool isFriend = (InstTemplate->getFriendObjectKind() != Decl::FOK_None);
944
945  // Link the instantiation back to the pattern *unless* this is a
946  // non-definition friend declaration.
947  if (!InstTemplate->getInstantiatedFromMemberTemplate() &&
948      !(isFriend && !D->getTemplatedDecl()->isThisDeclarationADefinition()))
949    InstTemplate->setInstantiatedFromMemberTemplate(D);
950
951  // Make declarations visible in the appropriate context.
952  if (!isFriend)
953    Owner->addDecl(InstTemplate);
954
955  return InstTemplate;
956}
957
958Decl *TemplateDeclInstantiator::VisitCXXRecordDecl(CXXRecordDecl *D) {
959  CXXRecordDecl *PrevDecl = 0;
960  if (D->isInjectedClassName())
961    PrevDecl = cast<CXXRecordDecl>(Owner);
962  else if (D->getPreviousDeclaration()) {
963    NamedDecl *Prev = SemaRef.FindInstantiatedDecl(D->getLocation(),
964                                                   D->getPreviousDeclaration(),
965                                                   TemplateArgs);
966    if (!Prev) return 0;
967    PrevDecl = cast<CXXRecordDecl>(Prev);
968  }
969
970  CXXRecordDecl *Record
971    = CXXRecordDecl::Create(SemaRef.Context, D->getTagKind(), Owner,
972                            D->getLocStart(), D->getLocation(),
973                            D->getIdentifier(), PrevDecl);
974
975  // Substitute the nested name specifier, if any.
976  if (SubstQualifier(D, Record))
977    return 0;
978
979  Record->setImplicit(D->isImplicit());
980  // FIXME: Check against AS_none is an ugly hack to work around the issue that
981  // the tag decls introduced by friend class declarations don't have an access
982  // specifier. Remove once this area of the code gets sorted out.
983  if (D->getAccess() != AS_none)
984    Record->setAccess(D->getAccess());
985  if (!D->isInjectedClassName())
986    Record->setInstantiationOfMemberClass(D, TSK_ImplicitInstantiation);
987
988  // If the original function was part of a friend declaration,
989  // inherit its namespace state.
990  if (Decl::FriendObjectKind FOK = D->getFriendObjectKind())
991    Record->setObjectOfFriendDecl(FOK == Decl::FOK_Declared);
992
993  // Make sure that anonymous structs and unions are recorded.
994  if (D->isAnonymousStructOrUnion()) {
995    Record->setAnonymousStructOrUnion(true);
996    if (Record->getDeclContext()->getRedeclContext()->isFunctionOrMethod())
997      SemaRef.CurrentInstantiationScope->InstantiatedLocal(D, Record);
998  }
999
1000  Owner->addDecl(Record);
1001  return Record;
1002}
1003
1004/// Normal class members are of more specific types and therefore
1005/// don't make it here.  This function serves two purposes:
1006///   1) instantiating function templates
1007///   2) substituting friend declarations
1008/// FIXME: preserve function definitions in case #2
1009Decl *TemplateDeclInstantiator::VisitFunctionDecl(FunctionDecl *D,
1010                                       TemplateParameterList *TemplateParams) {
1011  // Check whether there is already a function template specialization for
1012  // this declaration.
1013  FunctionTemplateDecl *FunctionTemplate = D->getDescribedFunctionTemplate();
1014  void *InsertPos = 0;
1015  if (FunctionTemplate && !TemplateParams) {
1016    std::pair<const TemplateArgument *, unsigned> Innermost
1017      = TemplateArgs.getInnermost();
1018
1019    FunctionDecl *SpecFunc
1020      = FunctionTemplate->findSpecialization(Innermost.first, Innermost.second,
1021                                             InsertPos);
1022
1023    // If we already have a function template specialization, return it.
1024    if (SpecFunc)
1025      return SpecFunc;
1026  }
1027
1028  bool isFriend;
1029  if (FunctionTemplate)
1030    isFriend = (FunctionTemplate->getFriendObjectKind() != Decl::FOK_None);
1031  else
1032    isFriend = (D->getFriendObjectKind() != Decl::FOK_None);
1033
1034  bool MergeWithParentScope = (TemplateParams != 0) ||
1035    Owner->isFunctionOrMethod() ||
1036    !(isa<Decl>(Owner) &&
1037      cast<Decl>(Owner)->isDefinedOutsideFunctionOrMethod());
1038  LocalInstantiationScope Scope(SemaRef, MergeWithParentScope);
1039
1040  SmallVector<ParmVarDecl *, 4> Params;
1041  TypeSourceInfo *TInfo = D->getTypeSourceInfo();
1042  TInfo = SubstFunctionType(D, Params);
1043  if (!TInfo)
1044    return 0;
1045  QualType T = TInfo->getType();
1046
1047  NestedNameSpecifierLoc QualifierLoc = D->getQualifierLoc();
1048  if (QualifierLoc) {
1049    QualifierLoc = SemaRef.SubstNestedNameSpecifierLoc(QualifierLoc,
1050                                                       TemplateArgs);
1051    if (!QualifierLoc)
1052      return 0;
1053  }
1054
1055  // If we're instantiating a local function declaration, put the result
1056  // in the owner;  otherwise we need to find the instantiated context.
1057  DeclContext *DC;
1058  if (D->getDeclContext()->isFunctionOrMethod())
1059    DC = Owner;
1060  else if (isFriend && QualifierLoc) {
1061    CXXScopeSpec SS;
1062    SS.Adopt(QualifierLoc);
1063    DC = SemaRef.computeDeclContext(SS);
1064    if (!DC) return 0;
1065  } else {
1066    DC = SemaRef.FindInstantiatedContext(D->getLocation(), D->getDeclContext(),
1067                                         TemplateArgs);
1068  }
1069
1070  FunctionDecl *Function =
1071      FunctionDecl::Create(SemaRef.Context, DC, D->getInnerLocStart(),
1072                           D->getLocation(), D->getDeclName(), T, TInfo,
1073                           D->getStorageClass(), D->getStorageClassAsWritten(),
1074                           D->isInlineSpecified(), D->hasWrittenPrototype(),
1075                           /*isConstexpr*/ false);
1076
1077  if (QualifierLoc)
1078    Function->setQualifierInfo(QualifierLoc);
1079
1080  DeclContext *LexicalDC = Owner;
1081  if (!isFriend && D->isOutOfLine()) {
1082    assert(D->getDeclContext()->isFileContext());
1083    LexicalDC = D->getDeclContext();
1084  }
1085
1086  Function->setLexicalDeclContext(LexicalDC);
1087
1088  // Attach the parameters
1089  if (isa<FunctionProtoType>(Function->getType().IgnoreParens())) {
1090    // Adopt the already-instantiated parameters into our own context.
1091    for (unsigned P = 0; P < Params.size(); ++P)
1092      if (Params[P])
1093        Params[P]->setOwningFunction(Function);
1094  } else {
1095    // Since we were instantiated via a typedef of a function type, create
1096    // new parameters.
1097    const FunctionProtoType *Proto
1098      = Function->getType()->getAs<FunctionProtoType>();
1099    assert(Proto && "No function prototype in template instantiation?");
1100    for (FunctionProtoType::arg_type_iterator AI = Proto->arg_type_begin(),
1101         AE = Proto->arg_type_end(); AI != AE; ++AI) {
1102      ParmVarDecl *Param
1103        = SemaRef.BuildParmVarDeclForTypedef(Function, Function->getLocation(),
1104                                             *AI);
1105      Param->setScopeInfo(0, Params.size());
1106      Params.push_back(Param);
1107    }
1108  }
1109  Function->setParams(Params);
1110
1111  SourceLocation InstantiateAtPOI;
1112  if (TemplateParams) {
1113    // Our resulting instantiation is actually a function template, since we
1114    // are substituting only the outer template parameters. For example, given
1115    //
1116    //   template<typename T>
1117    //   struct X {
1118    //     template<typename U> friend void f(T, U);
1119    //   };
1120    //
1121    //   X<int> x;
1122    //
1123    // We are instantiating the friend function template "f" within X<int>,
1124    // which means substituting int for T, but leaving "f" as a friend function
1125    // template.
1126    // Build the function template itself.
1127    FunctionTemplate = FunctionTemplateDecl::Create(SemaRef.Context, DC,
1128                                                    Function->getLocation(),
1129                                                    Function->getDeclName(),
1130                                                    TemplateParams, Function);
1131    Function->setDescribedFunctionTemplate(FunctionTemplate);
1132
1133    FunctionTemplate->setLexicalDeclContext(LexicalDC);
1134
1135    if (isFriend && D->isThisDeclarationADefinition()) {
1136      // TODO: should we remember this connection regardless of whether
1137      // the friend declaration provided a body?
1138      FunctionTemplate->setInstantiatedFromMemberTemplate(
1139                                           D->getDescribedFunctionTemplate());
1140    }
1141  } else if (FunctionTemplate) {
1142    // Record this function template specialization.
1143    std::pair<const TemplateArgument *, unsigned> Innermost
1144      = TemplateArgs.getInnermost();
1145    Function->setFunctionTemplateSpecialization(FunctionTemplate,
1146                            TemplateArgumentList::CreateCopy(SemaRef.Context,
1147                                                             Innermost.first,
1148                                                             Innermost.second),
1149                                                InsertPos);
1150  } else if (isFriend) {
1151    // Note, we need this connection even if the friend doesn't have a body.
1152    // Its body may exist but not have been attached yet due to deferred
1153    // parsing.
1154    // FIXME: It might be cleaner to set this when attaching the body to the
1155    // friend function declaration, however that would require finding all the
1156    // instantiations and modifying them.
1157    Function->setInstantiationOfMemberFunction(D, TSK_ImplicitInstantiation);
1158  }
1159
1160  if (InitFunctionInstantiation(Function, D))
1161    Function->setInvalidDecl();
1162
1163  bool isExplicitSpecialization = false;
1164
1165  LookupResult Previous(SemaRef, Function->getDeclName(), SourceLocation(),
1166                        Sema::LookupOrdinaryName, Sema::ForRedeclaration);
1167
1168  if (DependentFunctionTemplateSpecializationInfo *Info
1169        = D->getDependentSpecializationInfo()) {
1170    assert(isFriend && "non-friend has dependent specialization info?");
1171
1172    // This needs to be set now for future sanity.
1173    Function->setObjectOfFriendDecl(/*HasPrevious*/ true);
1174
1175    // Instantiate the explicit template arguments.
1176    TemplateArgumentListInfo ExplicitArgs(Info->getLAngleLoc(),
1177                                          Info->getRAngleLoc());
1178    if (SemaRef.Subst(Info->getTemplateArgs(), Info->getNumTemplateArgs(),
1179                      ExplicitArgs, TemplateArgs))
1180      return 0;
1181
1182    // Map the candidate templates to their instantiations.
1183    for (unsigned I = 0, E = Info->getNumTemplates(); I != E; ++I) {
1184      Decl *Temp = SemaRef.FindInstantiatedDecl(D->getLocation(),
1185                                                Info->getTemplate(I),
1186                                                TemplateArgs);
1187      if (!Temp) return 0;
1188
1189      Previous.addDecl(cast<FunctionTemplateDecl>(Temp));
1190    }
1191
1192    if (SemaRef.CheckFunctionTemplateSpecialization(Function,
1193                                                    &ExplicitArgs,
1194                                                    Previous))
1195      Function->setInvalidDecl();
1196
1197    isExplicitSpecialization = true;
1198
1199  } else if (TemplateParams || !FunctionTemplate) {
1200    // Look only into the namespace where the friend would be declared to
1201    // find a previous declaration. This is the innermost enclosing namespace,
1202    // as described in ActOnFriendFunctionDecl.
1203    SemaRef.LookupQualifiedName(Previous, DC);
1204
1205    // In C++, the previous declaration we find might be a tag type
1206    // (class or enum). In this case, the new declaration will hide the
1207    // tag type. Note that this does does not apply if we're declaring a
1208    // typedef (C++ [dcl.typedef]p4).
1209    if (Previous.isSingleTagDecl())
1210      Previous.clear();
1211  }
1212
1213  SemaRef.CheckFunctionDeclaration(/*Scope*/ 0, Function, Previous,
1214                                   isExplicitSpecialization);
1215
1216  NamedDecl *PrincipalDecl = (TemplateParams
1217                              ? cast<NamedDecl>(FunctionTemplate)
1218                              : Function);
1219
1220  // If the original function was part of a friend declaration,
1221  // inherit its namespace state and add it to the owner.
1222  if (isFriend) {
1223    NamedDecl *PrevDecl;
1224    if (TemplateParams)
1225      PrevDecl = FunctionTemplate->getPreviousDeclaration();
1226    else
1227      PrevDecl = Function->getPreviousDeclaration();
1228
1229    PrincipalDecl->setObjectOfFriendDecl(PrevDecl != 0);
1230    DC->makeDeclVisibleInContext(PrincipalDecl, /*Recoverable=*/ false);
1231
1232    bool queuedInstantiation = false;
1233
1234    // C++98 [temp.friend]p5: When a function is defined in a friend function
1235    //   declaration in a class template, the function is defined at each
1236    //   instantiation of the class template. The function is defined even if it
1237    //   is never used.
1238    // C++11 [temp.friend]p4: When a function is defined in a friend function
1239    //   declaration in a class template, the function is instantiated when the
1240    //   function is odr-used.
1241    //
1242    // If -Wc++98-compat is enabled, we go through the motions of checking for a
1243    // redefinition, but don't instantiate the function.
1244    if ((!SemaRef.getLangOptions().CPlusPlus0x ||
1245         SemaRef.Diags.getDiagnosticLevel(
1246             diag::warn_cxx98_compat_friend_redefinition,
1247             Function->getLocation())
1248           != DiagnosticsEngine::Ignored) &&
1249        D->isThisDeclarationADefinition()) {
1250      // Check for a function body.
1251      const FunctionDecl *Definition = 0;
1252      if (Function->isDefined(Definition) &&
1253          Definition->getTemplateSpecializationKind() == TSK_Undeclared) {
1254        SemaRef.Diag(Function->getLocation(),
1255                     SemaRef.getLangOptions().CPlusPlus0x ?
1256                       diag::warn_cxx98_compat_friend_redefinition :
1257                       diag::err_redefinition) << Function->getDeclName();
1258        SemaRef.Diag(Definition->getLocation(), diag::note_previous_definition);
1259        if (!SemaRef.getLangOptions().CPlusPlus0x)
1260          Function->setInvalidDecl();
1261      }
1262      // Check for redefinitions due to other instantiations of this or
1263      // a similar friend function.
1264      else for (FunctionDecl::redecl_iterator R = Function->redecls_begin(),
1265                                           REnd = Function->redecls_end();
1266                R != REnd; ++R) {
1267        if (*R == Function)
1268          continue;
1269        switch (R->getFriendObjectKind()) {
1270        case Decl::FOK_None:
1271          if (!SemaRef.getLangOptions().CPlusPlus0x &&
1272              !queuedInstantiation && R->isUsed(false)) {
1273            if (MemberSpecializationInfo *MSInfo
1274                = Function->getMemberSpecializationInfo()) {
1275              if (MSInfo->getPointOfInstantiation().isInvalid()) {
1276                SourceLocation Loc = R->getLocation(); // FIXME
1277                MSInfo->setPointOfInstantiation(Loc);
1278                SemaRef.PendingLocalImplicitInstantiations.push_back(
1279                                                 std::make_pair(Function, Loc));
1280                queuedInstantiation = true;
1281              }
1282            }
1283          }
1284          break;
1285        default:
1286          if (const FunctionDecl *RPattern
1287              = R->getTemplateInstantiationPattern())
1288            if (RPattern->isDefined(RPattern)) {
1289              SemaRef.Diag(Function->getLocation(),
1290                           SemaRef.getLangOptions().CPlusPlus0x ?
1291                             diag::warn_cxx98_compat_friend_redefinition :
1292                             diag::err_redefinition)
1293                << Function->getDeclName();
1294              SemaRef.Diag(R->getLocation(), diag::note_previous_definition);
1295              if (!SemaRef.getLangOptions().CPlusPlus0x)
1296                Function->setInvalidDecl();
1297              break;
1298            }
1299        }
1300      }
1301    }
1302  }
1303
1304  if (Function->isOverloadedOperator() && !DC->isRecord() &&
1305      PrincipalDecl->isInIdentifierNamespace(Decl::IDNS_Ordinary))
1306    PrincipalDecl->setNonMemberOperator();
1307
1308  assert(!D->isDefaulted() && "only methods should be defaulted");
1309  return Function;
1310}
1311
1312Decl *
1313TemplateDeclInstantiator::VisitCXXMethodDecl(CXXMethodDecl *D,
1314                                      TemplateParameterList *TemplateParams,
1315                                      bool IsClassScopeSpecialization) {
1316  FunctionTemplateDecl *FunctionTemplate = D->getDescribedFunctionTemplate();
1317  void *InsertPos = 0;
1318  if (FunctionTemplate && !TemplateParams) {
1319    // We are creating a function template specialization from a function
1320    // template. Check whether there is already a function template
1321    // specialization for this particular set of template arguments.
1322    std::pair<const TemplateArgument *, unsigned> Innermost
1323      = TemplateArgs.getInnermost();
1324
1325    FunctionDecl *SpecFunc
1326      = FunctionTemplate->findSpecialization(Innermost.first, Innermost.second,
1327                                             InsertPos);
1328
1329    // If we already have a function template specialization, return it.
1330    if (SpecFunc)
1331      return SpecFunc;
1332  }
1333
1334  bool isFriend;
1335  if (FunctionTemplate)
1336    isFriend = (FunctionTemplate->getFriendObjectKind() != Decl::FOK_None);
1337  else
1338    isFriend = (D->getFriendObjectKind() != Decl::FOK_None);
1339
1340  bool MergeWithParentScope = (TemplateParams != 0) ||
1341    !(isa<Decl>(Owner) &&
1342      cast<Decl>(Owner)->isDefinedOutsideFunctionOrMethod());
1343  LocalInstantiationScope Scope(SemaRef, MergeWithParentScope);
1344
1345  // Instantiate enclosing template arguments for friends.
1346  SmallVector<TemplateParameterList *, 4> TempParamLists;
1347  unsigned NumTempParamLists = 0;
1348  if (isFriend && (NumTempParamLists = D->getNumTemplateParameterLists())) {
1349    TempParamLists.set_size(NumTempParamLists);
1350    for (unsigned I = 0; I != NumTempParamLists; ++I) {
1351      TemplateParameterList *TempParams = D->getTemplateParameterList(I);
1352      TemplateParameterList *InstParams = SubstTemplateParams(TempParams);
1353      if (!InstParams)
1354        return NULL;
1355      TempParamLists[I] = InstParams;
1356    }
1357  }
1358
1359  SmallVector<ParmVarDecl *, 4> Params;
1360  TypeSourceInfo *TInfo = D->getTypeSourceInfo();
1361  TInfo = SubstFunctionType(D, Params);
1362  if (!TInfo)
1363    return 0;
1364  QualType T = TInfo->getType();
1365
1366  // \brief If the type of this function, after ignoring parentheses,
1367  // is not *directly* a function type, then we're instantiating a function
1368  // that was declared via a typedef, e.g.,
1369  //
1370  //   typedef int functype(int, int);
1371  //   functype func;
1372  //
1373  // In this case, we'll just go instantiate the ParmVarDecls that we
1374  // synthesized in the method declaration.
1375  if (!isa<FunctionProtoType>(T.IgnoreParens())) {
1376    assert(!Params.size() && "Instantiating type could not yield parameters");
1377    SmallVector<QualType, 4> ParamTypes;
1378    if (SemaRef.SubstParmTypes(D->getLocation(), D->param_begin(),
1379                               D->getNumParams(), TemplateArgs, ParamTypes,
1380                               &Params))
1381      return 0;
1382  }
1383
1384  NestedNameSpecifierLoc QualifierLoc = D->getQualifierLoc();
1385  if (QualifierLoc) {
1386    QualifierLoc = SemaRef.SubstNestedNameSpecifierLoc(QualifierLoc,
1387                                                 TemplateArgs);
1388    if (!QualifierLoc)
1389      return 0;
1390  }
1391
1392  DeclContext *DC = Owner;
1393  if (isFriend) {
1394    if (QualifierLoc) {
1395      CXXScopeSpec SS;
1396      SS.Adopt(QualifierLoc);
1397      DC = SemaRef.computeDeclContext(SS);
1398
1399      if (DC && SemaRef.RequireCompleteDeclContext(SS, DC))
1400        return 0;
1401    } else {
1402      DC = SemaRef.FindInstantiatedContext(D->getLocation(),
1403                                           D->getDeclContext(),
1404                                           TemplateArgs);
1405    }
1406    if (!DC) return 0;
1407  }
1408
1409  // Build the instantiated method declaration.
1410  CXXRecordDecl *Record = cast<CXXRecordDecl>(DC);
1411  CXXMethodDecl *Method = 0;
1412
1413  SourceLocation StartLoc = D->getInnerLocStart();
1414  DeclarationNameInfo NameInfo
1415    = SemaRef.SubstDeclarationNameInfo(D->getNameInfo(), TemplateArgs);
1416  if (CXXConstructorDecl *Constructor = dyn_cast<CXXConstructorDecl>(D)) {
1417    Method = CXXConstructorDecl::Create(SemaRef.Context, Record,
1418                                        StartLoc, NameInfo, T, TInfo,
1419                                        Constructor->isExplicit(),
1420                                        Constructor->isInlineSpecified(),
1421                                        false, /*isConstexpr*/ false);
1422  } else if (CXXDestructorDecl *Destructor = dyn_cast<CXXDestructorDecl>(D)) {
1423    Method = CXXDestructorDecl::Create(SemaRef.Context, Record,
1424                                       StartLoc, NameInfo, T, TInfo,
1425                                       Destructor->isInlineSpecified(),
1426                                       false);
1427  } else if (CXXConversionDecl *Conversion = dyn_cast<CXXConversionDecl>(D)) {
1428    Method = CXXConversionDecl::Create(SemaRef.Context, Record,
1429                                       StartLoc, NameInfo, T, TInfo,
1430                                       Conversion->isInlineSpecified(),
1431                                       Conversion->isExplicit(),
1432                                       /*isConstexpr*/ false,
1433                                       Conversion->getLocEnd());
1434  } else {
1435    Method = CXXMethodDecl::Create(SemaRef.Context, Record,
1436                                   StartLoc, NameInfo, T, TInfo,
1437                                   D->isStatic(),
1438                                   D->getStorageClassAsWritten(),
1439                                   D->isInlineSpecified(),
1440                                   /*isConstexpr*/ false, D->getLocEnd());
1441  }
1442
1443  if (QualifierLoc)
1444    Method->setQualifierInfo(QualifierLoc);
1445
1446  if (TemplateParams) {
1447    // Our resulting instantiation is actually a function template, since we
1448    // are substituting only the outer template parameters. For example, given
1449    //
1450    //   template<typename T>
1451    //   struct X {
1452    //     template<typename U> void f(T, U);
1453    //   };
1454    //
1455    //   X<int> x;
1456    //
1457    // We are instantiating the member template "f" within X<int>, which means
1458    // substituting int for T, but leaving "f" as a member function template.
1459    // Build the function template itself.
1460    FunctionTemplate = FunctionTemplateDecl::Create(SemaRef.Context, Record,
1461                                                    Method->getLocation(),
1462                                                    Method->getDeclName(),
1463                                                    TemplateParams, Method);
1464    if (isFriend) {
1465      FunctionTemplate->setLexicalDeclContext(Owner);
1466      FunctionTemplate->setObjectOfFriendDecl(true);
1467    } else if (D->isOutOfLine())
1468      FunctionTemplate->setLexicalDeclContext(D->getLexicalDeclContext());
1469    Method->setDescribedFunctionTemplate(FunctionTemplate);
1470  } else if (FunctionTemplate) {
1471    // Record this function template specialization.
1472    std::pair<const TemplateArgument *, unsigned> Innermost
1473      = TemplateArgs.getInnermost();
1474    Method->setFunctionTemplateSpecialization(FunctionTemplate,
1475                         TemplateArgumentList::CreateCopy(SemaRef.Context,
1476                                                          Innermost.first,
1477                                                          Innermost.second),
1478                                              InsertPos);
1479  } else if (!isFriend) {
1480    // Record that this is an instantiation of a member function.
1481    Method->setInstantiationOfMemberFunction(D, TSK_ImplicitInstantiation);
1482  }
1483
1484  // If we are instantiating a member function defined
1485  // out-of-line, the instantiation will have the same lexical
1486  // context (which will be a namespace scope) as the template.
1487  if (isFriend) {
1488    if (NumTempParamLists)
1489      Method->setTemplateParameterListsInfo(SemaRef.Context,
1490                                            NumTempParamLists,
1491                                            TempParamLists.data());
1492
1493    Method->setLexicalDeclContext(Owner);
1494    Method->setObjectOfFriendDecl(true);
1495  } else if (D->isOutOfLine())
1496    Method->setLexicalDeclContext(D->getLexicalDeclContext());
1497
1498  // Attach the parameters
1499  for (unsigned P = 0; P < Params.size(); ++P)
1500    Params[P]->setOwningFunction(Method);
1501  Method->setParams(Params);
1502
1503  if (InitMethodInstantiation(Method, D))
1504    Method->setInvalidDecl();
1505
1506  LookupResult Previous(SemaRef, NameInfo, Sema::LookupOrdinaryName,
1507                        Sema::ForRedeclaration);
1508
1509  if (!FunctionTemplate || TemplateParams || isFriend) {
1510    SemaRef.LookupQualifiedName(Previous, Record);
1511
1512    // In C++, the previous declaration we find might be a tag type
1513    // (class or enum). In this case, the new declaration will hide the
1514    // tag type. Note that this does does not apply if we're declaring a
1515    // typedef (C++ [dcl.typedef]p4).
1516    if (Previous.isSingleTagDecl())
1517      Previous.clear();
1518  }
1519
1520  if (!IsClassScopeSpecialization)
1521    SemaRef.CheckFunctionDeclaration(0, Method, Previous, false);
1522
1523  if (D->isPure())
1524    SemaRef.CheckPureMethod(Method, SourceRange());
1525
1526  Method->setAccess(D->getAccess());
1527
1528  SemaRef.CheckOverrideControl(Method);
1529
1530  if (FunctionTemplate) {
1531    // If there's a function template, let our caller handle it.
1532  } else if (Method->isInvalidDecl() && !Previous.empty()) {
1533    // Don't hide a (potentially) valid declaration with an invalid one.
1534  } else {
1535    NamedDecl *DeclToAdd = (TemplateParams
1536                            ? cast<NamedDecl>(FunctionTemplate)
1537                            : Method);
1538    if (isFriend)
1539      Record->makeDeclVisibleInContext(DeclToAdd);
1540    else if (!IsClassScopeSpecialization)
1541      Owner->addDecl(DeclToAdd);
1542  }
1543
1544  if (D->isExplicitlyDefaulted()) {
1545    SemaRef.SetDeclDefaulted(Method, Method->getLocation());
1546  } else {
1547    assert(!D->isDefaulted() &&
1548           "should not implicitly default uninstantiated function");
1549  }
1550
1551  return Method;
1552}
1553
1554Decl *TemplateDeclInstantiator::VisitCXXConstructorDecl(CXXConstructorDecl *D) {
1555  return VisitCXXMethodDecl(D);
1556}
1557
1558Decl *TemplateDeclInstantiator::VisitCXXDestructorDecl(CXXDestructorDecl *D) {
1559  return VisitCXXMethodDecl(D);
1560}
1561
1562Decl *TemplateDeclInstantiator::VisitCXXConversionDecl(CXXConversionDecl *D) {
1563  return VisitCXXMethodDecl(D);
1564}
1565
1566ParmVarDecl *TemplateDeclInstantiator::VisitParmVarDecl(ParmVarDecl *D) {
1567  return SemaRef.SubstParmVarDecl(D, TemplateArgs, /*indexAdjustment*/ 0,
1568                                  llvm::Optional<unsigned>());
1569}
1570
1571Decl *TemplateDeclInstantiator::VisitTemplateTypeParmDecl(
1572                                                    TemplateTypeParmDecl *D) {
1573  // TODO: don't always clone when decls are refcounted.
1574  assert(D->getTypeForDecl()->isTemplateTypeParmType());
1575
1576  TemplateTypeParmDecl *Inst =
1577    TemplateTypeParmDecl::Create(SemaRef.Context, Owner,
1578                                 D->getLocStart(), D->getLocation(),
1579                                 D->getDepth() - TemplateArgs.getNumLevels(),
1580                                 D->getIndex(), D->getIdentifier(),
1581                                 D->wasDeclaredWithTypename(),
1582                                 D->isParameterPack());
1583  Inst->setAccess(AS_public);
1584
1585  if (D->hasDefaultArgument())
1586    Inst->setDefaultArgument(D->getDefaultArgumentInfo(), false);
1587
1588  // Introduce this template parameter's instantiation into the instantiation
1589  // scope.
1590  SemaRef.CurrentInstantiationScope->InstantiatedLocal(D, Inst);
1591
1592  return Inst;
1593}
1594
1595Decl *TemplateDeclInstantiator::VisitNonTypeTemplateParmDecl(
1596                                                 NonTypeTemplateParmDecl *D) {
1597  // Substitute into the type of the non-type template parameter.
1598  TypeLoc TL = D->getTypeSourceInfo()->getTypeLoc();
1599  SmallVector<TypeSourceInfo *, 4> ExpandedParameterPackTypesAsWritten;
1600  SmallVector<QualType, 4> ExpandedParameterPackTypes;
1601  bool IsExpandedParameterPack = false;
1602  TypeSourceInfo *DI;
1603  QualType T;
1604  bool Invalid = false;
1605
1606  if (D->isExpandedParameterPack()) {
1607    // The non-type template parameter pack is an already-expanded pack
1608    // expansion of types. Substitute into each of the expanded types.
1609    ExpandedParameterPackTypes.reserve(D->getNumExpansionTypes());
1610    ExpandedParameterPackTypesAsWritten.reserve(D->getNumExpansionTypes());
1611    for (unsigned I = 0, N = D->getNumExpansionTypes(); I != N; ++I) {
1612      TypeSourceInfo *NewDI =SemaRef.SubstType(D->getExpansionTypeSourceInfo(I),
1613                                               TemplateArgs,
1614                                               D->getLocation(),
1615                                               D->getDeclName());
1616      if (!NewDI)
1617        return 0;
1618
1619      ExpandedParameterPackTypesAsWritten.push_back(NewDI);
1620      QualType NewT =SemaRef.CheckNonTypeTemplateParameterType(NewDI->getType(),
1621                                                              D->getLocation());
1622      if (NewT.isNull())
1623        return 0;
1624      ExpandedParameterPackTypes.push_back(NewT);
1625    }
1626
1627    IsExpandedParameterPack = true;
1628    DI = D->getTypeSourceInfo();
1629    T = DI->getType();
1630  } else if (isa<PackExpansionTypeLoc>(TL)) {
1631    // The non-type template parameter pack's type is a pack expansion of types.
1632    // Determine whether we need to expand this parameter pack into separate
1633    // types.
1634    PackExpansionTypeLoc Expansion = cast<PackExpansionTypeLoc>(TL);
1635    TypeLoc Pattern = Expansion.getPatternLoc();
1636    SmallVector<UnexpandedParameterPack, 2> Unexpanded;
1637    SemaRef.collectUnexpandedParameterPacks(Pattern, Unexpanded);
1638
1639    // Determine whether the set of unexpanded parameter packs can and should
1640    // be expanded.
1641    bool Expand = true;
1642    bool RetainExpansion = false;
1643    llvm::Optional<unsigned> OrigNumExpansions
1644      = Expansion.getTypePtr()->getNumExpansions();
1645    llvm::Optional<unsigned> NumExpansions = OrigNumExpansions;
1646    if (SemaRef.CheckParameterPacksForExpansion(Expansion.getEllipsisLoc(),
1647                                                Pattern.getSourceRange(),
1648                                                Unexpanded,
1649                                                TemplateArgs,
1650                                                Expand, RetainExpansion,
1651                                                NumExpansions))
1652      return 0;
1653
1654    if (Expand) {
1655      for (unsigned I = 0; I != *NumExpansions; ++I) {
1656        Sema::ArgumentPackSubstitutionIndexRAII SubstIndex(SemaRef, I);
1657        TypeSourceInfo *NewDI = SemaRef.SubstType(Pattern, TemplateArgs,
1658                                                  D->getLocation(),
1659                                                  D->getDeclName());
1660        if (!NewDI)
1661          return 0;
1662
1663        ExpandedParameterPackTypesAsWritten.push_back(NewDI);
1664        QualType NewT = SemaRef.CheckNonTypeTemplateParameterType(
1665                                                              NewDI->getType(),
1666                                                              D->getLocation());
1667        if (NewT.isNull())
1668          return 0;
1669        ExpandedParameterPackTypes.push_back(NewT);
1670      }
1671
1672      // Note that we have an expanded parameter pack. The "type" of this
1673      // expanded parameter pack is the original expansion type, but callers
1674      // will end up using the expanded parameter pack types for type-checking.
1675      IsExpandedParameterPack = true;
1676      DI = D->getTypeSourceInfo();
1677      T = DI->getType();
1678    } else {
1679      // We cannot fully expand the pack expansion now, so substitute into the
1680      // pattern and create a new pack expansion type.
1681      Sema::ArgumentPackSubstitutionIndexRAII SubstIndex(SemaRef, -1);
1682      TypeSourceInfo *NewPattern = SemaRef.SubstType(Pattern, TemplateArgs,
1683                                                     D->getLocation(),
1684                                                     D->getDeclName());
1685      if (!NewPattern)
1686        return 0;
1687
1688      DI = SemaRef.CheckPackExpansion(NewPattern, Expansion.getEllipsisLoc(),
1689                                      NumExpansions);
1690      if (!DI)
1691        return 0;
1692
1693      T = DI->getType();
1694    }
1695  } else {
1696    // Simple case: substitution into a parameter that is not a parameter pack.
1697    DI = SemaRef.SubstType(D->getTypeSourceInfo(), TemplateArgs,
1698                           D->getLocation(), D->getDeclName());
1699    if (!DI)
1700      return 0;
1701
1702    // Check that this type is acceptable for a non-type template parameter.
1703    T = SemaRef.CheckNonTypeTemplateParameterType(DI->getType(),
1704                                                  D->getLocation());
1705    if (T.isNull()) {
1706      T = SemaRef.Context.IntTy;
1707      Invalid = true;
1708    }
1709  }
1710
1711  NonTypeTemplateParmDecl *Param;
1712  if (IsExpandedParameterPack)
1713    Param = NonTypeTemplateParmDecl::Create(SemaRef.Context, Owner,
1714                                            D->getInnerLocStart(),
1715                                            D->getLocation(),
1716                                    D->getDepth() - TemplateArgs.getNumLevels(),
1717                                            D->getPosition(),
1718                                            D->getIdentifier(), T,
1719                                            DI,
1720                                            ExpandedParameterPackTypes.data(),
1721                                            ExpandedParameterPackTypes.size(),
1722                                    ExpandedParameterPackTypesAsWritten.data());
1723  else
1724    Param = NonTypeTemplateParmDecl::Create(SemaRef.Context, Owner,
1725                                            D->getInnerLocStart(),
1726                                            D->getLocation(),
1727                                    D->getDepth() - TemplateArgs.getNumLevels(),
1728                                            D->getPosition(),
1729                                            D->getIdentifier(), T,
1730                                            D->isParameterPack(), DI);
1731
1732  Param->setAccess(AS_public);
1733  if (Invalid)
1734    Param->setInvalidDecl();
1735
1736  Param->setDefaultArgument(D->getDefaultArgument(), false);
1737
1738  // Introduce this template parameter's instantiation into the instantiation
1739  // scope.
1740  SemaRef.CurrentInstantiationScope->InstantiatedLocal(D, Param);
1741  return Param;
1742}
1743
1744Decl *
1745TemplateDeclInstantiator::VisitTemplateTemplateParmDecl(
1746                                                  TemplateTemplateParmDecl *D) {
1747  // Instantiate the template parameter list of the template template parameter.
1748  TemplateParameterList *TempParams = D->getTemplateParameters();
1749  TemplateParameterList *InstParams;
1750  {
1751    // Perform the actual substitution of template parameters within a new,
1752    // local instantiation scope.
1753    LocalInstantiationScope Scope(SemaRef);
1754    InstParams = SubstTemplateParams(TempParams);
1755    if (!InstParams)
1756      return NULL;
1757  }
1758
1759  // Build the template template parameter.
1760  TemplateTemplateParmDecl *Param
1761    = TemplateTemplateParmDecl::Create(SemaRef.Context, Owner, D->getLocation(),
1762                                   D->getDepth() - TemplateArgs.getNumLevels(),
1763                                       D->getPosition(), D->isParameterPack(),
1764                                       D->getIdentifier(), InstParams);
1765  Param->setDefaultArgument(D->getDefaultArgument(), false);
1766  Param->setAccess(AS_public);
1767
1768  // Introduce this template parameter's instantiation into the instantiation
1769  // scope.
1770  SemaRef.CurrentInstantiationScope->InstantiatedLocal(D, Param);
1771
1772  return Param;
1773}
1774
1775Decl *TemplateDeclInstantiator::VisitUsingDirectiveDecl(UsingDirectiveDecl *D) {
1776  // Using directives are never dependent (and never contain any types or
1777  // expressions), so they require no explicit instantiation work.
1778
1779  UsingDirectiveDecl *Inst
1780    = UsingDirectiveDecl::Create(SemaRef.Context, Owner, D->getLocation(),
1781                                 D->getNamespaceKeyLocation(),
1782                                 D->getQualifierLoc(),
1783                                 D->getIdentLocation(),
1784                                 D->getNominatedNamespace(),
1785                                 D->getCommonAncestor());
1786  Owner->addDecl(Inst);
1787  return Inst;
1788}
1789
1790Decl *TemplateDeclInstantiator::VisitUsingDecl(UsingDecl *D) {
1791
1792  // The nested name specifier may be dependent, for example
1793  //     template <typename T> struct t {
1794  //       struct s1 { T f1(); };
1795  //       struct s2 : s1 { using s1::f1; };
1796  //     };
1797  //     template struct t<int>;
1798  // Here, in using s1::f1, s1 refers to t<T>::s1;
1799  // we need to substitute for t<int>::s1.
1800  NestedNameSpecifierLoc QualifierLoc
1801    = SemaRef.SubstNestedNameSpecifierLoc(D->getQualifierLoc(),
1802                                          TemplateArgs);
1803  if (!QualifierLoc)
1804    return 0;
1805
1806  // The name info is non-dependent, so no transformation
1807  // is required.
1808  DeclarationNameInfo NameInfo = D->getNameInfo();
1809
1810  // We only need to do redeclaration lookups if we're in a class
1811  // scope (in fact, it's not really even possible in non-class
1812  // scopes).
1813  bool CheckRedeclaration = Owner->isRecord();
1814
1815  LookupResult Prev(SemaRef, NameInfo, Sema::LookupUsingDeclName,
1816                    Sema::ForRedeclaration);
1817
1818  UsingDecl *NewUD = UsingDecl::Create(SemaRef.Context, Owner,
1819                                       D->getUsingLocation(),
1820                                       QualifierLoc,
1821                                       NameInfo,
1822                                       D->isTypeName());
1823
1824  CXXScopeSpec SS;
1825  SS.Adopt(QualifierLoc);
1826  if (CheckRedeclaration) {
1827    Prev.setHideTags(false);
1828    SemaRef.LookupQualifiedName(Prev, Owner);
1829
1830    // Check for invalid redeclarations.
1831    if (SemaRef.CheckUsingDeclRedeclaration(D->getUsingLocation(),
1832                                            D->isTypeName(), SS,
1833                                            D->getLocation(), Prev))
1834      NewUD->setInvalidDecl();
1835
1836  }
1837
1838  if (!NewUD->isInvalidDecl() &&
1839      SemaRef.CheckUsingDeclQualifier(D->getUsingLocation(), SS,
1840                                      D->getLocation()))
1841    NewUD->setInvalidDecl();
1842
1843  SemaRef.Context.setInstantiatedFromUsingDecl(NewUD, D);
1844  NewUD->setAccess(D->getAccess());
1845  Owner->addDecl(NewUD);
1846
1847  // Don't process the shadow decls for an invalid decl.
1848  if (NewUD->isInvalidDecl())
1849    return NewUD;
1850
1851  bool isFunctionScope = Owner->isFunctionOrMethod();
1852
1853  // Process the shadow decls.
1854  for (UsingDecl::shadow_iterator I = D->shadow_begin(), E = D->shadow_end();
1855         I != E; ++I) {
1856    UsingShadowDecl *Shadow = *I;
1857    NamedDecl *InstTarget =
1858      cast_or_null<NamedDecl>(SemaRef.FindInstantiatedDecl(
1859                                                          Shadow->getLocation(),
1860                                                        Shadow->getTargetDecl(),
1861                                                           TemplateArgs));
1862    if (!InstTarget)
1863      return 0;
1864
1865    if (CheckRedeclaration &&
1866        SemaRef.CheckUsingShadowDecl(NewUD, InstTarget, Prev))
1867      continue;
1868
1869    UsingShadowDecl *InstShadow
1870      = SemaRef.BuildUsingShadowDecl(/*Scope*/ 0, NewUD, InstTarget);
1871    SemaRef.Context.setInstantiatedFromUsingShadowDecl(InstShadow, Shadow);
1872
1873    if (isFunctionScope)
1874      SemaRef.CurrentInstantiationScope->InstantiatedLocal(Shadow, InstShadow);
1875  }
1876
1877  return NewUD;
1878}
1879
1880Decl *TemplateDeclInstantiator::VisitUsingShadowDecl(UsingShadowDecl *D) {
1881  // Ignore these;  we handle them in bulk when processing the UsingDecl.
1882  return 0;
1883}
1884
1885Decl * TemplateDeclInstantiator
1886    ::VisitUnresolvedUsingTypenameDecl(UnresolvedUsingTypenameDecl *D) {
1887  NestedNameSpecifierLoc QualifierLoc
1888    = SemaRef.SubstNestedNameSpecifierLoc(D->getQualifierLoc(),
1889                                          TemplateArgs);
1890  if (!QualifierLoc)
1891    return 0;
1892
1893  CXXScopeSpec SS;
1894  SS.Adopt(QualifierLoc);
1895
1896  // Since NameInfo refers to a typename, it cannot be a C++ special name.
1897  // Hence, no tranformation is required for it.
1898  DeclarationNameInfo NameInfo(D->getDeclName(), D->getLocation());
1899  NamedDecl *UD =
1900    SemaRef.BuildUsingDeclaration(/*Scope*/ 0, D->getAccess(),
1901                                  D->getUsingLoc(), SS, NameInfo, 0,
1902                                  /*instantiation*/ true,
1903                                  /*typename*/ true, D->getTypenameLoc());
1904  if (UD)
1905    SemaRef.Context.setInstantiatedFromUsingDecl(cast<UsingDecl>(UD), D);
1906
1907  return UD;
1908}
1909
1910Decl * TemplateDeclInstantiator
1911    ::VisitUnresolvedUsingValueDecl(UnresolvedUsingValueDecl *D) {
1912  NestedNameSpecifierLoc QualifierLoc
1913      = SemaRef.SubstNestedNameSpecifierLoc(D->getQualifierLoc(), TemplateArgs);
1914  if (!QualifierLoc)
1915    return 0;
1916
1917  CXXScopeSpec SS;
1918  SS.Adopt(QualifierLoc);
1919
1920  DeclarationNameInfo NameInfo
1921    = SemaRef.SubstDeclarationNameInfo(D->getNameInfo(), TemplateArgs);
1922
1923  NamedDecl *UD =
1924    SemaRef.BuildUsingDeclaration(/*Scope*/ 0, D->getAccess(),
1925                                  D->getUsingLoc(), SS, NameInfo, 0,
1926                                  /*instantiation*/ true,
1927                                  /*typename*/ false, SourceLocation());
1928  if (UD)
1929    SemaRef.Context.setInstantiatedFromUsingDecl(cast<UsingDecl>(UD), D);
1930
1931  return UD;
1932}
1933
1934
1935Decl *TemplateDeclInstantiator::VisitClassScopeFunctionSpecializationDecl(
1936                                     ClassScopeFunctionSpecializationDecl *Decl) {
1937  CXXMethodDecl *OldFD = Decl->getSpecialization();
1938  CXXMethodDecl *NewFD = cast<CXXMethodDecl>(VisitCXXMethodDecl(OldFD, 0, true));
1939
1940  LookupResult Previous(SemaRef, NewFD->getNameInfo(), Sema::LookupOrdinaryName,
1941                        Sema::ForRedeclaration);
1942
1943  SemaRef.LookupQualifiedName(Previous, SemaRef.CurContext);
1944  if (SemaRef.CheckFunctionTemplateSpecialization(NewFD, 0, Previous)) {
1945    NewFD->setInvalidDecl();
1946    return NewFD;
1947  }
1948
1949  // Associate the specialization with the pattern.
1950  FunctionDecl *Specialization = cast<FunctionDecl>(Previous.getFoundDecl());
1951  assert(Specialization && "Class scope Specialization is null");
1952  SemaRef.Context.setClassScopeSpecializationPattern(Specialization, OldFD);
1953
1954  return NewFD;
1955}
1956
1957Decl *Sema::SubstDecl(Decl *D, DeclContext *Owner,
1958                      const MultiLevelTemplateArgumentList &TemplateArgs) {
1959  TemplateDeclInstantiator Instantiator(*this, Owner, TemplateArgs);
1960  if (D->isInvalidDecl())
1961    return 0;
1962
1963  return Instantiator.Visit(D);
1964}
1965
1966/// \brief Instantiates a nested template parameter list in the current
1967/// instantiation context.
1968///
1969/// \param L The parameter list to instantiate
1970///
1971/// \returns NULL if there was an error
1972TemplateParameterList *
1973TemplateDeclInstantiator::SubstTemplateParams(TemplateParameterList *L) {
1974  // Get errors for all the parameters before bailing out.
1975  bool Invalid = false;
1976
1977  unsigned N = L->size();
1978  typedef SmallVector<NamedDecl *, 8> ParamVector;
1979  ParamVector Params;
1980  Params.reserve(N);
1981  for (TemplateParameterList::iterator PI = L->begin(), PE = L->end();
1982       PI != PE; ++PI) {
1983    NamedDecl *D = cast_or_null<NamedDecl>(Visit(*PI));
1984    Params.push_back(D);
1985    Invalid = Invalid || !D || D->isInvalidDecl();
1986  }
1987
1988  // Clean up if we had an error.
1989  if (Invalid)
1990    return NULL;
1991
1992  TemplateParameterList *InstL
1993    = TemplateParameterList::Create(SemaRef.Context, L->getTemplateLoc(),
1994                                    L->getLAngleLoc(), &Params.front(), N,
1995                                    L->getRAngleLoc());
1996  return InstL;
1997}
1998
1999/// \brief Instantiate the declaration of a class template partial
2000/// specialization.
2001///
2002/// \param ClassTemplate the (instantiated) class template that is partially
2003// specialized by the instantiation of \p PartialSpec.
2004///
2005/// \param PartialSpec the (uninstantiated) class template partial
2006/// specialization that we are instantiating.
2007///
2008/// \returns The instantiated partial specialization, if successful; otherwise,
2009/// NULL to indicate an error.
2010ClassTemplatePartialSpecializationDecl *
2011TemplateDeclInstantiator::InstantiateClassTemplatePartialSpecialization(
2012                                            ClassTemplateDecl *ClassTemplate,
2013                          ClassTemplatePartialSpecializationDecl *PartialSpec) {
2014  // Create a local instantiation scope for this class template partial
2015  // specialization, which will contain the instantiations of the template
2016  // parameters.
2017  LocalInstantiationScope Scope(SemaRef);
2018
2019  // Substitute into the template parameters of the class template partial
2020  // specialization.
2021  TemplateParameterList *TempParams = PartialSpec->getTemplateParameters();
2022  TemplateParameterList *InstParams = SubstTemplateParams(TempParams);
2023  if (!InstParams)
2024    return 0;
2025
2026  // Substitute into the template arguments of the class template partial
2027  // specialization.
2028  TemplateArgumentListInfo InstTemplateArgs; // no angle locations
2029  if (SemaRef.Subst(PartialSpec->getTemplateArgsAsWritten(),
2030                    PartialSpec->getNumTemplateArgsAsWritten(),
2031                    InstTemplateArgs, TemplateArgs))
2032    return 0;
2033
2034  // Check that the template argument list is well-formed for this
2035  // class template.
2036  SmallVector<TemplateArgument, 4> Converted;
2037  if (SemaRef.CheckTemplateArgumentList(ClassTemplate,
2038                                        PartialSpec->getLocation(),
2039                                        InstTemplateArgs,
2040                                        false,
2041                                        Converted))
2042    return 0;
2043
2044  // Figure out where to insert this class template partial specialization
2045  // in the member template's set of class template partial specializations.
2046  void *InsertPos = 0;
2047  ClassTemplateSpecializationDecl *PrevDecl
2048    = ClassTemplate->findPartialSpecialization(Converted.data(),
2049                                               Converted.size(), InsertPos);
2050
2051  // Build the canonical type that describes the converted template
2052  // arguments of the class template partial specialization.
2053  QualType CanonType
2054    = SemaRef.Context.getTemplateSpecializationType(TemplateName(ClassTemplate),
2055                                                    Converted.data(),
2056                                                    Converted.size());
2057
2058  // Build the fully-sugared type for this class template
2059  // specialization as the user wrote in the specialization
2060  // itself. This means that we'll pretty-print the type retrieved
2061  // from the specialization's declaration the way that the user
2062  // actually wrote the specialization, rather than formatting the
2063  // name based on the "canonical" representation used to store the
2064  // template arguments in the specialization.
2065  TypeSourceInfo *WrittenTy
2066    = SemaRef.Context.getTemplateSpecializationTypeInfo(
2067                                                    TemplateName(ClassTemplate),
2068                                                    PartialSpec->getLocation(),
2069                                                    InstTemplateArgs,
2070                                                    CanonType);
2071
2072  if (PrevDecl) {
2073    // We've already seen a partial specialization with the same template
2074    // parameters and template arguments. This can happen, for example, when
2075    // substituting the outer template arguments ends up causing two
2076    // class template partial specializations of a member class template
2077    // to have identical forms, e.g.,
2078    //
2079    //   template<typename T, typename U>
2080    //   struct Outer {
2081    //     template<typename X, typename Y> struct Inner;
2082    //     template<typename Y> struct Inner<T, Y>;
2083    //     template<typename Y> struct Inner<U, Y>;
2084    //   };
2085    //
2086    //   Outer<int, int> outer; // error: the partial specializations of Inner
2087    //                          // have the same signature.
2088    SemaRef.Diag(PartialSpec->getLocation(), diag::err_partial_spec_redeclared)
2089      << WrittenTy->getType();
2090    SemaRef.Diag(PrevDecl->getLocation(), diag::note_prev_partial_spec_here)
2091      << SemaRef.Context.getTypeDeclType(PrevDecl);
2092    return 0;
2093  }
2094
2095
2096  // Create the class template partial specialization declaration.
2097  ClassTemplatePartialSpecializationDecl *InstPartialSpec
2098    = ClassTemplatePartialSpecializationDecl::Create(SemaRef.Context,
2099                                                     PartialSpec->getTagKind(),
2100                                                     Owner,
2101                                                     PartialSpec->getLocStart(),
2102                                                     PartialSpec->getLocation(),
2103                                                     InstParams,
2104                                                     ClassTemplate,
2105                                                     Converted.data(),
2106                                                     Converted.size(),
2107                                                     InstTemplateArgs,
2108                                                     CanonType,
2109                                                     0,
2110                             ClassTemplate->getNextPartialSpecSequenceNumber());
2111  // Substitute the nested name specifier, if any.
2112  if (SubstQualifier(PartialSpec, InstPartialSpec))
2113    return 0;
2114
2115  InstPartialSpec->setInstantiatedFromMember(PartialSpec);
2116  InstPartialSpec->setTypeAsWritten(WrittenTy);
2117
2118  // Add this partial specialization to the set of class template partial
2119  // specializations.
2120  ClassTemplate->AddPartialSpecialization(InstPartialSpec, InsertPos);
2121  return InstPartialSpec;
2122}
2123
2124TypeSourceInfo*
2125TemplateDeclInstantiator::SubstFunctionType(FunctionDecl *D,
2126                              SmallVectorImpl<ParmVarDecl *> &Params) {
2127  TypeSourceInfo *OldTInfo = D->getTypeSourceInfo();
2128  assert(OldTInfo && "substituting function without type source info");
2129  assert(Params.empty() && "parameter vector is non-empty at start");
2130  TypeSourceInfo *NewTInfo
2131    = SemaRef.SubstFunctionDeclType(OldTInfo, TemplateArgs,
2132                                    D->getTypeSpecStartLoc(),
2133                                    D->getDeclName());
2134  if (!NewTInfo)
2135    return 0;
2136
2137  if (NewTInfo != OldTInfo) {
2138    // Get parameters from the new type info.
2139    TypeLoc OldTL = OldTInfo->getTypeLoc().IgnoreParens();
2140    if (FunctionProtoTypeLoc *OldProtoLoc
2141                                  = dyn_cast<FunctionProtoTypeLoc>(&OldTL)) {
2142      TypeLoc NewTL = NewTInfo->getTypeLoc().IgnoreParens();
2143      FunctionProtoTypeLoc *NewProtoLoc = cast<FunctionProtoTypeLoc>(&NewTL);
2144      assert(NewProtoLoc && "Missing prototype?");
2145      unsigned NewIdx = 0, NumNewParams = NewProtoLoc->getNumArgs();
2146      for (unsigned OldIdx = 0, NumOldParams = OldProtoLoc->getNumArgs();
2147           OldIdx != NumOldParams; ++OldIdx) {
2148        ParmVarDecl *OldParam = OldProtoLoc->getArg(OldIdx);
2149        if (!OldParam->isParameterPack() ||
2150            (NewIdx < NumNewParams &&
2151             NewProtoLoc->getArg(NewIdx)->isParameterPack())) {
2152          // Simple case: normal parameter, or a parameter pack that's
2153          // instantiated to a (still-dependent) parameter pack.
2154          ParmVarDecl *NewParam = NewProtoLoc->getArg(NewIdx++);
2155          Params.push_back(NewParam);
2156          SemaRef.CurrentInstantiationScope->InstantiatedLocal(OldParam,
2157                                                               NewParam);
2158          continue;
2159        }
2160
2161        // Parameter pack: make the instantiation an argument pack.
2162        SemaRef.CurrentInstantiationScope->MakeInstantiatedLocalArgPack(
2163                                                                      OldParam);
2164        unsigned NumArgumentsInExpansion
2165          = SemaRef.getNumArgumentsInExpansion(OldParam->getType(),
2166                                               TemplateArgs);
2167        while (NumArgumentsInExpansion--) {
2168          ParmVarDecl *NewParam = NewProtoLoc->getArg(NewIdx++);
2169          Params.push_back(NewParam);
2170          SemaRef.CurrentInstantiationScope->InstantiatedLocalPackArg(OldParam,
2171                                                                      NewParam);
2172        }
2173      }
2174    }
2175  } else {
2176    // The function type itself was not dependent and therefore no
2177    // substitution occurred. However, we still need to instantiate
2178    // the function parameters themselves.
2179    TypeLoc OldTL = OldTInfo->getTypeLoc().IgnoreParens();
2180    if (FunctionProtoTypeLoc *OldProtoLoc
2181                                    = dyn_cast<FunctionProtoTypeLoc>(&OldTL)) {
2182      for (unsigned i = 0, i_end = OldProtoLoc->getNumArgs(); i != i_end; ++i) {
2183        ParmVarDecl *Parm = VisitParmVarDecl(OldProtoLoc->getArg(i));
2184        if (!Parm)
2185          return 0;
2186        Params.push_back(Parm);
2187      }
2188    }
2189  }
2190  return NewTInfo;
2191}
2192
2193/// \brief Initializes the common fields of an instantiation function
2194/// declaration (New) from the corresponding fields of its template (Tmpl).
2195///
2196/// \returns true if there was an error
2197bool
2198TemplateDeclInstantiator::InitFunctionInstantiation(FunctionDecl *New,
2199                                                    FunctionDecl *Tmpl) {
2200  if (Tmpl->isDeletedAsWritten())
2201    New->setDeletedAsWritten();
2202
2203  // If we are performing substituting explicitly-specified template arguments
2204  // or deduced template arguments into a function template and we reach this
2205  // point, we are now past the point where SFINAE applies and have committed
2206  // to keeping the new function template specialization. We therefore
2207  // convert the active template instantiation for the function template
2208  // into a template instantiation for this specific function template
2209  // specialization, which is not a SFINAE context, so that we diagnose any
2210  // further errors in the declaration itself.
2211  typedef Sema::ActiveTemplateInstantiation ActiveInstType;
2212  ActiveInstType &ActiveInst = SemaRef.ActiveTemplateInstantiations.back();
2213  if (ActiveInst.Kind == ActiveInstType::ExplicitTemplateArgumentSubstitution ||
2214      ActiveInst.Kind == ActiveInstType::DeducedTemplateArgumentSubstitution) {
2215    if (FunctionTemplateDecl *FunTmpl
2216          = dyn_cast<FunctionTemplateDecl>((Decl *)ActiveInst.Entity)) {
2217      assert(FunTmpl->getTemplatedDecl() == Tmpl &&
2218             "Deduction from the wrong function template?");
2219      (void) FunTmpl;
2220      ActiveInst.Kind = ActiveInstType::TemplateInstantiation;
2221      ActiveInst.Entity = reinterpret_cast<uintptr_t>(New);
2222      --SemaRef.NonInstantiationEntries;
2223    }
2224  }
2225
2226  const FunctionProtoType *Proto = Tmpl->getType()->getAs<FunctionProtoType>();
2227  assert(Proto && "Function template without prototype?");
2228
2229  if (Proto->hasExceptionSpec() || Proto->getNoReturnAttr()) {
2230    // The function has an exception specification or a "noreturn"
2231    // attribute. Substitute into each of the exception types.
2232    SmallVector<QualType, 4> Exceptions;
2233    for (unsigned I = 0, N = Proto->getNumExceptions(); I != N; ++I) {
2234      // FIXME: Poor location information!
2235      if (const PackExpansionType *PackExpansion
2236            = Proto->getExceptionType(I)->getAs<PackExpansionType>()) {
2237        // We have a pack expansion. Instantiate it.
2238        SmallVector<UnexpandedParameterPack, 2> Unexpanded;
2239        SemaRef.collectUnexpandedParameterPacks(PackExpansion->getPattern(),
2240                                                Unexpanded);
2241        assert(!Unexpanded.empty() &&
2242               "Pack expansion without parameter packs?");
2243
2244        bool Expand = false;
2245        bool RetainExpansion = false;
2246        llvm::Optional<unsigned> NumExpansions
2247                                          = PackExpansion->getNumExpansions();
2248        if (SemaRef.CheckParameterPacksForExpansion(New->getLocation(),
2249                                                    SourceRange(),
2250                                                    Unexpanded,
2251                                                    TemplateArgs,
2252                                                    Expand,
2253                                                    RetainExpansion,
2254                                                    NumExpansions))
2255          break;
2256
2257        if (!Expand) {
2258          // We can't expand this pack expansion into separate arguments yet;
2259          // just substitute into the pattern and create a new pack expansion
2260          // type.
2261          Sema::ArgumentPackSubstitutionIndexRAII SubstIndex(SemaRef, -1);
2262          QualType T = SemaRef.SubstType(PackExpansion->getPattern(),
2263                                         TemplateArgs,
2264                                       New->getLocation(), New->getDeclName());
2265          if (T.isNull())
2266            break;
2267
2268          T = SemaRef.Context.getPackExpansionType(T, NumExpansions);
2269          Exceptions.push_back(T);
2270          continue;
2271        }
2272
2273        // Substitute into the pack expansion pattern for each template
2274        bool Invalid = false;
2275        for (unsigned ArgIdx = 0; ArgIdx != *NumExpansions; ++ArgIdx) {
2276          Sema::ArgumentPackSubstitutionIndexRAII SubstIndex(SemaRef, ArgIdx);
2277
2278          QualType T = SemaRef.SubstType(PackExpansion->getPattern(),
2279                                         TemplateArgs,
2280                                       New->getLocation(), New->getDeclName());
2281          if (T.isNull()) {
2282            Invalid = true;
2283            break;
2284          }
2285
2286          Exceptions.push_back(T);
2287        }
2288
2289        if (Invalid)
2290          break;
2291
2292        continue;
2293      }
2294
2295      QualType T
2296        = SemaRef.SubstType(Proto->getExceptionType(I), TemplateArgs,
2297                            New->getLocation(), New->getDeclName());
2298      if (T.isNull() ||
2299          SemaRef.CheckSpecifiedExceptionType(T, New->getLocation()))
2300        continue;
2301
2302      Exceptions.push_back(T);
2303    }
2304    Expr *NoexceptExpr = 0;
2305    if (Expr *OldNoexceptExpr = Proto->getNoexceptExpr()) {
2306      EnterExpressionEvaluationContext Unevaluated(SemaRef, Sema::Unevaluated);
2307      ExprResult E = SemaRef.SubstExpr(OldNoexceptExpr, TemplateArgs);
2308      if (E.isUsable())
2309        E = SemaRef.CheckBooleanCondition(E.get(), E.get()->getLocStart());
2310
2311      if (E.isUsable()) {
2312        SourceLocation ErrLoc;
2313        llvm::APSInt NoexceptVal;
2314        NoexceptExpr = E.take();
2315        if (!NoexceptExpr->isTypeDependent() &&
2316            !NoexceptExpr->isValueDependent() &&
2317            !NoexceptExpr->isIntegerConstantExpr(NoexceptVal, SemaRef.Context,
2318                                                 &ErrLoc, /*evaluated=*/false)){
2319          SemaRef.Diag(ErrLoc, diag::err_noexcept_needs_constant_expression)
2320            << NoexceptExpr->getSourceRange();
2321          NoexceptExpr = 0;
2322        }
2323      }
2324    }
2325
2326    // Rebuild the function type
2327
2328    FunctionProtoType::ExtProtoInfo EPI = Proto->getExtProtoInfo();
2329    EPI.ExceptionSpecType = Proto->getExceptionSpecType();
2330    EPI.NumExceptions = Exceptions.size();
2331    EPI.Exceptions = Exceptions.data();
2332    EPI.NoexceptExpr = NoexceptExpr;
2333    EPI.ExtInfo = Proto->getExtInfo();
2334
2335    const FunctionProtoType *NewProto
2336      = New->getType()->getAs<FunctionProtoType>();
2337    assert(NewProto && "Template instantiation without function prototype?");
2338    New->setType(SemaRef.Context.getFunctionType(NewProto->getResultType(),
2339                                                 NewProto->arg_type_begin(),
2340                                                 NewProto->getNumArgs(),
2341                                                 EPI));
2342  }
2343
2344  // C++0x [dcl.constexpr]p6: If the instantiated template specialization of
2345  // a constexpr function template satisfies the requirements for a constexpr
2346  // function, then it is a constexpr function.
2347  if (Tmpl->isConstexpr() &&
2348      SemaRef.CheckConstexprFunctionDecl(New, Sema::CCK_Instantiation))
2349    New->setConstexpr(true);
2350
2351  const FunctionDecl* Definition = Tmpl;
2352
2353  // Get the definition. Leaves the variable unchanged if undefined.
2354  Tmpl->isDefined(Definition);
2355
2356  SemaRef.InstantiateAttrs(TemplateArgs, Definition, New);
2357
2358  return false;
2359}
2360
2361/// \brief Initializes common fields of an instantiated method
2362/// declaration (New) from the corresponding fields of its template
2363/// (Tmpl).
2364///
2365/// \returns true if there was an error
2366bool
2367TemplateDeclInstantiator::InitMethodInstantiation(CXXMethodDecl *New,
2368                                                  CXXMethodDecl *Tmpl) {
2369  if (InitFunctionInstantiation(New, Tmpl))
2370    return true;
2371
2372  New->setAccess(Tmpl->getAccess());
2373  if (Tmpl->isVirtualAsWritten())
2374    New->setVirtualAsWritten(true);
2375
2376  // FIXME: attributes
2377  // FIXME: New needs a pointer to Tmpl
2378  return false;
2379}
2380
2381/// \brief Instantiate the definition of the given function from its
2382/// template.
2383///
2384/// \param PointOfInstantiation the point at which the instantiation was
2385/// required. Note that this is not precisely a "point of instantiation"
2386/// for the function, but it's close.
2387///
2388/// \param Function the already-instantiated declaration of a
2389/// function template specialization or member function of a class template
2390/// specialization.
2391///
2392/// \param Recursive if true, recursively instantiates any functions that
2393/// are required by this instantiation.
2394///
2395/// \param DefinitionRequired if true, then we are performing an explicit
2396/// instantiation where the body of the function is required. Complain if
2397/// there is no such body.
2398void Sema::InstantiateFunctionDefinition(SourceLocation PointOfInstantiation,
2399                                         FunctionDecl *Function,
2400                                         bool Recursive,
2401                                         bool DefinitionRequired) {
2402  if (Function->isInvalidDecl() || Function->isDefined())
2403    return;
2404
2405  // Never instantiate an explicit specialization except if it is a class scope
2406  // explicit specialization.
2407  if (Function->getTemplateSpecializationKind() == TSK_ExplicitSpecialization &&
2408      !Function->getClassScopeSpecializationPattern())
2409    return;
2410
2411  // Find the function body that we'll be substituting.
2412  const FunctionDecl *PatternDecl = Function->getTemplateInstantiationPattern();
2413  assert(PatternDecl && "instantiating a non-template");
2414
2415  Stmt *Pattern = PatternDecl->getBody(PatternDecl);
2416  assert(PatternDecl && "template definition is not a template");
2417  if (!Pattern) {
2418    // Try to find a defaulted definition
2419    PatternDecl->isDefined(PatternDecl);
2420  }
2421  assert(PatternDecl && "template definition is not a template");
2422
2423  // Postpone late parsed template instantiations.
2424  if (PatternDecl->isLateTemplateParsed() &&
2425      !LateTemplateParser) {
2426    PendingInstantiations.push_back(
2427      std::make_pair(Function, PointOfInstantiation));
2428    return;
2429  }
2430
2431  // Call the LateTemplateParser callback if there a need to late parse
2432  // a templated function definition.
2433  if (!Pattern && PatternDecl->isLateTemplateParsed() &&
2434      LateTemplateParser) {
2435    LateTemplateParser(OpaqueParser, PatternDecl);
2436    Pattern = PatternDecl->getBody(PatternDecl);
2437  }
2438
2439  if (!Pattern && !PatternDecl->isDefaulted()) {
2440    if (DefinitionRequired) {
2441      if (Function->getPrimaryTemplate())
2442        Diag(PointOfInstantiation,
2443             diag::err_explicit_instantiation_undefined_func_template)
2444          << Function->getPrimaryTemplate();
2445      else
2446        Diag(PointOfInstantiation,
2447             diag::err_explicit_instantiation_undefined_member)
2448          << 1 << Function->getDeclName() << Function->getDeclContext();
2449
2450      if (PatternDecl)
2451        Diag(PatternDecl->getLocation(),
2452             diag::note_explicit_instantiation_here);
2453      Function->setInvalidDecl();
2454    } else if (Function->getTemplateSpecializationKind()
2455                 == TSK_ExplicitInstantiationDefinition) {
2456      PendingInstantiations.push_back(
2457        std::make_pair(Function, PointOfInstantiation));
2458    }
2459
2460    return;
2461  }
2462
2463  // C++0x [temp.explicit]p9:
2464  //   Except for inline functions, other explicit instantiation declarations
2465  //   have the effect of suppressing the implicit instantiation of the entity
2466  //   to which they refer.
2467  if (Function->getTemplateSpecializationKind()
2468        == TSK_ExplicitInstantiationDeclaration &&
2469      !PatternDecl->isInlined())
2470    return;
2471
2472  InstantiatingTemplate Inst(*this, PointOfInstantiation, Function);
2473  if (Inst)
2474    return;
2475
2476  // If we're performing recursive template instantiation, create our own
2477  // queue of pending implicit instantiations that we will instantiate later,
2478  // while we're still within our own instantiation context.
2479  SmallVector<VTableUse, 16> SavedVTableUses;
2480  std::deque<PendingImplicitInstantiation> SavedPendingInstantiations;
2481  if (Recursive) {
2482    VTableUses.swap(SavedVTableUses);
2483    PendingInstantiations.swap(SavedPendingInstantiations);
2484  }
2485
2486  EnterExpressionEvaluationContext EvalContext(*this,
2487                                               Sema::PotentiallyEvaluated);
2488  ActOnStartOfFunctionDef(0, Function);
2489
2490  // Introduce a new scope where local variable instantiations will be
2491  // recorded, unless we're actually a member function within a local
2492  // class, in which case we need to merge our results with the parent
2493  // scope (of the enclosing function).
2494  bool MergeWithParentScope = false;
2495  if (CXXRecordDecl *Rec = dyn_cast<CXXRecordDecl>(Function->getDeclContext()))
2496    MergeWithParentScope = Rec->isLocalClass();
2497
2498  LocalInstantiationScope Scope(*this, MergeWithParentScope);
2499
2500  // Introduce the instantiated function parameters into the local
2501  // instantiation scope, and set the parameter names to those used
2502  // in the template.
2503  unsigned FParamIdx = 0;
2504  for (unsigned I = 0, N = PatternDecl->getNumParams(); I != N; ++I) {
2505    const ParmVarDecl *PatternParam = PatternDecl->getParamDecl(I);
2506    if (!PatternParam->isParameterPack()) {
2507      // Simple case: not a parameter pack.
2508      assert(FParamIdx < Function->getNumParams());
2509      ParmVarDecl *FunctionParam = Function->getParamDecl(I);
2510      FunctionParam->setDeclName(PatternParam->getDeclName());
2511      Scope.InstantiatedLocal(PatternParam, FunctionParam);
2512      ++FParamIdx;
2513      continue;
2514    }
2515
2516    // Expand the parameter pack.
2517    Scope.MakeInstantiatedLocalArgPack(PatternParam);
2518    for (unsigned NumFParams = Function->getNumParams();
2519         FParamIdx < NumFParams;
2520         ++FParamIdx) {
2521      ParmVarDecl *FunctionParam = Function->getParamDecl(FParamIdx);
2522      FunctionParam->setDeclName(PatternParam->getDeclName());
2523      Scope.InstantiatedLocalPackArg(PatternParam, FunctionParam);
2524    }
2525  }
2526
2527  // Enter the scope of this instantiation. We don't use
2528  // PushDeclContext because we don't have a scope.
2529  Sema::ContextRAII savedContext(*this, Function);
2530
2531  MultiLevelTemplateArgumentList TemplateArgs =
2532    getTemplateInstantiationArgs(Function, 0, false, PatternDecl);
2533
2534  if (PatternDecl->isDefaulted()) {
2535    ActOnFinishFunctionBody(Function, 0, /*IsInstantiation=*/true);
2536
2537    SetDeclDefaulted(Function, PatternDecl->getLocation());
2538  } else {
2539    // If this is a constructor, instantiate the member initializers.
2540    if (const CXXConstructorDecl *Ctor =
2541          dyn_cast<CXXConstructorDecl>(PatternDecl)) {
2542      InstantiateMemInitializers(cast<CXXConstructorDecl>(Function), Ctor,
2543                                 TemplateArgs);
2544    }
2545
2546    // Instantiate the function body.
2547    StmtResult Body = SubstStmt(Pattern, TemplateArgs);
2548
2549    if (Body.isInvalid())
2550      Function->setInvalidDecl();
2551
2552    ActOnFinishFunctionBody(Function, Body.get(),
2553                            /*IsInstantiation=*/true);
2554  }
2555
2556  PerformDependentDiagnostics(PatternDecl, TemplateArgs);
2557
2558  savedContext.pop();
2559
2560  DeclGroupRef DG(Function);
2561  Consumer.HandleTopLevelDecl(DG);
2562
2563  // This class may have local implicit instantiations that need to be
2564  // instantiation within this scope.
2565  PerformPendingInstantiations(/*LocalOnly=*/true);
2566  Scope.Exit();
2567
2568  if (Recursive) {
2569    // Define any pending vtables.
2570    DefineUsedVTables();
2571
2572    // Instantiate any pending implicit instantiations found during the
2573    // instantiation of this template.
2574    PerformPendingInstantiations();
2575
2576    // Restore the set of pending vtables.
2577    assert(VTableUses.empty() &&
2578           "VTableUses should be empty before it is discarded.");
2579    VTableUses.swap(SavedVTableUses);
2580
2581    // Restore the set of pending implicit instantiations.
2582    assert(PendingInstantiations.empty() &&
2583           "PendingInstantiations should be empty before it is discarded.");
2584    PendingInstantiations.swap(SavedPendingInstantiations);
2585  }
2586}
2587
2588/// \brief Instantiate the definition of the given variable from its
2589/// template.
2590///
2591/// \param PointOfInstantiation the point at which the instantiation was
2592/// required. Note that this is not precisely a "point of instantiation"
2593/// for the function, but it's close.
2594///
2595/// \param Var the already-instantiated declaration of a static member
2596/// variable of a class template specialization.
2597///
2598/// \param Recursive if true, recursively instantiates any functions that
2599/// are required by this instantiation.
2600///
2601/// \param DefinitionRequired if true, then we are performing an explicit
2602/// instantiation where an out-of-line definition of the member variable
2603/// is required. Complain if there is no such definition.
2604void Sema::InstantiateStaticDataMemberDefinition(
2605                                          SourceLocation PointOfInstantiation,
2606                                                 VarDecl *Var,
2607                                                 bool Recursive,
2608                                                 bool DefinitionRequired) {
2609  if (Var->isInvalidDecl())
2610    return;
2611
2612  // Find the out-of-line definition of this static data member.
2613  VarDecl *Def = Var->getInstantiatedFromStaticDataMember();
2614  assert(Def && "This data member was not instantiated from a template?");
2615  assert(Def->isStaticDataMember() && "Not a static data member?");
2616  Def = Def->getOutOfLineDefinition();
2617
2618  if (!Def) {
2619    // We did not find an out-of-line definition of this static data member,
2620    // so we won't perform any instantiation. Rather, we rely on the user to
2621    // instantiate this definition (or provide a specialization for it) in
2622    // another translation unit.
2623    if (DefinitionRequired) {
2624      Def = Var->getInstantiatedFromStaticDataMember();
2625      Diag(PointOfInstantiation,
2626           diag::err_explicit_instantiation_undefined_member)
2627        << 2 << Var->getDeclName() << Var->getDeclContext();
2628      Diag(Def->getLocation(), diag::note_explicit_instantiation_here);
2629    } else if (Var->getTemplateSpecializationKind()
2630                 == TSK_ExplicitInstantiationDefinition) {
2631      PendingInstantiations.push_back(
2632        std::make_pair(Var, PointOfInstantiation));
2633    }
2634
2635    return;
2636  }
2637
2638  // Never instantiate an explicit specialization.
2639  if (Var->getTemplateSpecializationKind() == TSK_ExplicitSpecialization)
2640    return;
2641
2642  // C++0x [temp.explicit]p9:
2643  //   Except for inline functions, other explicit instantiation declarations
2644  //   have the effect of suppressing the implicit instantiation of the entity
2645  //   to which they refer.
2646  if (Var->getTemplateSpecializationKind()
2647        == TSK_ExplicitInstantiationDeclaration)
2648    return;
2649
2650  // If we already have a definition, we're done.
2651  if (Var->getDefinition())
2652    return;
2653
2654  InstantiatingTemplate Inst(*this, PointOfInstantiation, Var);
2655  if (Inst)
2656    return;
2657
2658  // If we're performing recursive template instantiation, create our own
2659  // queue of pending implicit instantiations that we will instantiate later,
2660  // while we're still within our own instantiation context.
2661  SmallVector<VTableUse, 16> SavedVTableUses;
2662  std::deque<PendingImplicitInstantiation> SavedPendingInstantiations;
2663  if (Recursive) {
2664    VTableUses.swap(SavedVTableUses);
2665    PendingInstantiations.swap(SavedPendingInstantiations);
2666  }
2667
2668  // Enter the scope of this instantiation. We don't use
2669  // PushDeclContext because we don't have a scope.
2670  ContextRAII previousContext(*this, Var->getDeclContext());
2671
2672  VarDecl *OldVar = Var;
2673  Var = cast_or_null<VarDecl>(SubstDecl(Def, Var->getDeclContext(),
2674                                        getTemplateInstantiationArgs(Var)));
2675
2676  previousContext.pop();
2677
2678  if (Var) {
2679    MemberSpecializationInfo *MSInfo = OldVar->getMemberSpecializationInfo();
2680    assert(MSInfo && "Missing member specialization information?");
2681    Var->setTemplateSpecializationKind(MSInfo->getTemplateSpecializationKind(),
2682                                       MSInfo->getPointOfInstantiation());
2683    DeclGroupRef DG(Var);
2684    Consumer.HandleTopLevelDecl(DG);
2685  }
2686
2687  if (Recursive) {
2688    // Define any newly required vtables.
2689    DefineUsedVTables();
2690
2691    // Instantiate any pending implicit instantiations found during the
2692    // instantiation of this template.
2693    PerformPendingInstantiations();
2694
2695    // Restore the set of pending vtables.
2696    assert(VTableUses.empty() &&
2697           "VTableUses should be empty before it is discarded, "
2698           "while instantiating static data member.");
2699    VTableUses.swap(SavedVTableUses);
2700
2701    // Restore the set of pending implicit instantiations.
2702    assert(PendingInstantiations.empty() &&
2703           "PendingInstantiations should be empty before it is discarded, "
2704           "while instantiating static data member.");
2705    PendingInstantiations.swap(SavedPendingInstantiations);
2706  }
2707}
2708
2709static MultiInitializer CreateMultiInitializer(SmallVectorImpl<Expr*> &Args,
2710                                               const CXXCtorInitializer *Init) {
2711  // FIXME: This is a hack that will do slightly the wrong thing for an
2712  // initializer of the form foo({...}).
2713  // The right thing to do would be to modify InstantiateInitializer to create
2714  // the MultiInitializer.
2715  if (Args.size() == 1 && isa<InitListExpr>(Args[0]))
2716    return MultiInitializer(Args[0]);
2717  return MultiInitializer(Init->getLParenLoc(), Args.data(),
2718                          Args.size(), Init->getRParenLoc());
2719}
2720
2721void
2722Sema::InstantiateMemInitializers(CXXConstructorDecl *New,
2723                                 const CXXConstructorDecl *Tmpl,
2724                           const MultiLevelTemplateArgumentList &TemplateArgs) {
2725
2726  SmallVector<CXXCtorInitializer*, 4> NewInits;
2727  bool AnyErrors = false;
2728
2729  // Instantiate all the initializers.
2730  for (CXXConstructorDecl::init_const_iterator Inits = Tmpl->init_begin(),
2731                                            InitsEnd = Tmpl->init_end();
2732       Inits != InitsEnd; ++Inits) {
2733    CXXCtorInitializer *Init = *Inits;
2734
2735    // Only instantiate written initializers, let Sema re-construct implicit
2736    // ones.
2737    if (!Init->isWritten())
2738      continue;
2739
2740    SourceLocation LParenLoc, RParenLoc;
2741    ASTOwningVector<Expr*> NewArgs(*this);
2742
2743    SourceLocation EllipsisLoc;
2744
2745    if (Init->isPackExpansion()) {
2746      // This is a pack expansion. We should expand it now.
2747      TypeLoc BaseTL = Init->getTypeSourceInfo()->getTypeLoc();
2748      SmallVector<UnexpandedParameterPack, 2> Unexpanded;
2749      collectUnexpandedParameterPacks(BaseTL, Unexpanded);
2750      bool ShouldExpand = false;
2751      bool RetainExpansion = false;
2752      llvm::Optional<unsigned> NumExpansions;
2753      if (CheckParameterPacksForExpansion(Init->getEllipsisLoc(),
2754                                          BaseTL.getSourceRange(),
2755                                          Unexpanded,
2756                                          TemplateArgs, ShouldExpand,
2757                                          RetainExpansion,
2758                                          NumExpansions)) {
2759        AnyErrors = true;
2760        New->setInvalidDecl();
2761        continue;
2762      }
2763      assert(ShouldExpand && "Partial instantiation of base initializer?");
2764
2765      // Loop over all of the arguments in the argument pack(s),
2766      for (unsigned I = 0; I != *NumExpansions; ++I) {
2767        Sema::ArgumentPackSubstitutionIndexRAII SubstIndex(*this, I);
2768
2769        // Instantiate the initializer.
2770        if (InstantiateInitializer(Init->getInit(), TemplateArgs,
2771                                   LParenLoc, NewArgs, RParenLoc)) {
2772          AnyErrors = true;
2773          break;
2774        }
2775
2776        // Instantiate the base type.
2777        TypeSourceInfo *BaseTInfo = SubstType(Init->getTypeSourceInfo(),
2778                                              TemplateArgs,
2779                                              Init->getSourceLocation(),
2780                                              New->getDeclName());
2781        if (!BaseTInfo) {
2782          AnyErrors = true;
2783          break;
2784        }
2785
2786        // Build the initializer.
2787        MultiInitializer MultiInit(CreateMultiInitializer(NewArgs, Init));
2788        MemInitResult NewInit = BuildBaseInitializer(BaseTInfo->getType(),
2789                                                     BaseTInfo, MultiInit,
2790                                                     New->getParent(),
2791                                                     SourceLocation());
2792        if (NewInit.isInvalid()) {
2793          AnyErrors = true;
2794          break;
2795        }
2796
2797        NewInits.push_back(NewInit.get());
2798        NewArgs.clear();
2799      }
2800
2801      continue;
2802    }
2803
2804    // Instantiate the initializer.
2805    if (InstantiateInitializer(Init->getInit(), TemplateArgs,
2806                               LParenLoc, NewArgs, RParenLoc)) {
2807      AnyErrors = true;
2808      continue;
2809    }
2810
2811    MemInitResult NewInit;
2812    if (Init->isDelegatingInitializer() || Init->isBaseInitializer()) {
2813      TypeSourceInfo *TInfo = SubstType(Init->getTypeSourceInfo(),
2814                                        TemplateArgs,
2815                                        Init->getSourceLocation(),
2816                                        New->getDeclName());
2817      if (!TInfo) {
2818        AnyErrors = true;
2819        New->setInvalidDecl();
2820        continue;
2821      }
2822
2823      MultiInitializer MultiInit(CreateMultiInitializer(NewArgs, Init));
2824
2825      if (Init->isBaseInitializer())
2826        NewInit = BuildBaseInitializer(TInfo->getType(), TInfo, MultiInit,
2827                                       New->getParent(), EllipsisLoc);
2828      else
2829        NewInit = BuildDelegatingInitializer(TInfo, MultiInit,
2830                                  cast<CXXRecordDecl>(CurContext->getParent()));
2831    } else if (Init->isMemberInitializer()) {
2832      FieldDecl *Member = cast_or_null<FieldDecl>(FindInstantiatedDecl(
2833                                                     Init->getMemberLocation(),
2834                                                     Init->getMember(),
2835                                                     TemplateArgs));
2836      if (!Member) {
2837        AnyErrors = true;
2838        New->setInvalidDecl();
2839        continue;
2840      }
2841
2842      MultiInitializer MultiInit(CreateMultiInitializer(NewArgs, Init));
2843      NewInit = BuildMemberInitializer(Member, MultiInit,
2844                                       Init->getSourceLocation());
2845    } else if (Init->isIndirectMemberInitializer()) {
2846      IndirectFieldDecl *IndirectMember =
2847         cast_or_null<IndirectFieldDecl>(FindInstantiatedDecl(
2848                                 Init->getMemberLocation(),
2849                                 Init->getIndirectMember(), TemplateArgs));
2850
2851      if (!IndirectMember) {
2852        AnyErrors = true;
2853        New->setInvalidDecl();
2854        continue;
2855      }
2856
2857      MultiInitializer MultiInit(CreateMultiInitializer(NewArgs, Init));
2858      NewInit = BuildMemberInitializer(IndirectMember, MultiInit,
2859                                       Init->getSourceLocation());
2860    }
2861
2862    if (NewInit.isInvalid()) {
2863      AnyErrors = true;
2864      New->setInvalidDecl();
2865    } else {
2866      // FIXME: It would be nice if ASTOwningVector had a release function.
2867      NewArgs.take();
2868
2869      NewInits.push_back(NewInit.get());
2870    }
2871  }
2872
2873  // Assign all the initializers to the new constructor.
2874  ActOnMemInitializers(New,
2875                       /*FIXME: ColonLoc */
2876                       SourceLocation(),
2877                       NewInits.data(), NewInits.size(),
2878                       AnyErrors);
2879}
2880
2881// TODO: this could be templated if the various decl types used the
2882// same method name.
2883static bool isInstantiationOf(ClassTemplateDecl *Pattern,
2884                              ClassTemplateDecl *Instance) {
2885  Pattern = Pattern->getCanonicalDecl();
2886
2887  do {
2888    Instance = Instance->getCanonicalDecl();
2889    if (Pattern == Instance) return true;
2890    Instance = Instance->getInstantiatedFromMemberTemplate();
2891  } while (Instance);
2892
2893  return false;
2894}
2895
2896static bool isInstantiationOf(FunctionTemplateDecl *Pattern,
2897                              FunctionTemplateDecl *Instance) {
2898  Pattern = Pattern->getCanonicalDecl();
2899
2900  do {
2901    Instance = Instance->getCanonicalDecl();
2902    if (Pattern == Instance) return true;
2903    Instance = Instance->getInstantiatedFromMemberTemplate();
2904  } while (Instance);
2905
2906  return false;
2907}
2908
2909static bool
2910isInstantiationOf(ClassTemplatePartialSpecializationDecl *Pattern,
2911                  ClassTemplatePartialSpecializationDecl *Instance) {
2912  Pattern
2913    = cast<ClassTemplatePartialSpecializationDecl>(Pattern->getCanonicalDecl());
2914  do {
2915    Instance = cast<ClassTemplatePartialSpecializationDecl>(
2916                                                Instance->getCanonicalDecl());
2917    if (Pattern == Instance)
2918      return true;
2919    Instance = Instance->getInstantiatedFromMember();
2920  } while (Instance);
2921
2922  return false;
2923}
2924
2925static bool isInstantiationOf(CXXRecordDecl *Pattern,
2926                              CXXRecordDecl *Instance) {
2927  Pattern = Pattern->getCanonicalDecl();
2928
2929  do {
2930    Instance = Instance->getCanonicalDecl();
2931    if (Pattern == Instance) return true;
2932    Instance = Instance->getInstantiatedFromMemberClass();
2933  } while (Instance);
2934
2935  return false;
2936}
2937
2938static bool isInstantiationOf(FunctionDecl *Pattern,
2939                              FunctionDecl *Instance) {
2940  Pattern = Pattern->getCanonicalDecl();
2941
2942  do {
2943    Instance = Instance->getCanonicalDecl();
2944    if (Pattern == Instance) return true;
2945    Instance = Instance->getInstantiatedFromMemberFunction();
2946  } while (Instance);
2947
2948  return false;
2949}
2950
2951static bool isInstantiationOf(EnumDecl *Pattern,
2952                              EnumDecl *Instance) {
2953  Pattern = Pattern->getCanonicalDecl();
2954
2955  do {
2956    Instance = Instance->getCanonicalDecl();
2957    if (Pattern == Instance) return true;
2958    Instance = Instance->getInstantiatedFromMemberEnum();
2959  } while (Instance);
2960
2961  return false;
2962}
2963
2964static bool isInstantiationOf(UsingShadowDecl *Pattern,
2965                              UsingShadowDecl *Instance,
2966                              ASTContext &C) {
2967  return C.getInstantiatedFromUsingShadowDecl(Instance) == Pattern;
2968}
2969
2970static bool isInstantiationOf(UsingDecl *Pattern,
2971                              UsingDecl *Instance,
2972                              ASTContext &C) {
2973  return C.getInstantiatedFromUsingDecl(Instance) == Pattern;
2974}
2975
2976static bool isInstantiationOf(UnresolvedUsingValueDecl *Pattern,
2977                              UsingDecl *Instance,
2978                              ASTContext &C) {
2979  return C.getInstantiatedFromUsingDecl(Instance) == Pattern;
2980}
2981
2982static bool isInstantiationOf(UnresolvedUsingTypenameDecl *Pattern,
2983                              UsingDecl *Instance,
2984                              ASTContext &C) {
2985  return C.getInstantiatedFromUsingDecl(Instance) == Pattern;
2986}
2987
2988static bool isInstantiationOfStaticDataMember(VarDecl *Pattern,
2989                                              VarDecl *Instance) {
2990  assert(Instance->isStaticDataMember());
2991
2992  Pattern = Pattern->getCanonicalDecl();
2993
2994  do {
2995    Instance = Instance->getCanonicalDecl();
2996    if (Pattern == Instance) return true;
2997    Instance = Instance->getInstantiatedFromStaticDataMember();
2998  } while (Instance);
2999
3000  return false;
3001}
3002
3003// Other is the prospective instantiation
3004// D is the prospective pattern
3005static bool isInstantiationOf(ASTContext &Ctx, NamedDecl *D, Decl *Other) {
3006  if (D->getKind() != Other->getKind()) {
3007    if (UnresolvedUsingTypenameDecl *UUD
3008          = dyn_cast<UnresolvedUsingTypenameDecl>(D)) {
3009      if (UsingDecl *UD = dyn_cast<UsingDecl>(Other)) {
3010        return isInstantiationOf(UUD, UD, Ctx);
3011      }
3012    }
3013
3014    if (UnresolvedUsingValueDecl *UUD
3015          = dyn_cast<UnresolvedUsingValueDecl>(D)) {
3016      if (UsingDecl *UD = dyn_cast<UsingDecl>(Other)) {
3017        return isInstantiationOf(UUD, UD, Ctx);
3018      }
3019    }
3020
3021    return false;
3022  }
3023
3024  if (CXXRecordDecl *Record = dyn_cast<CXXRecordDecl>(Other))
3025    return isInstantiationOf(cast<CXXRecordDecl>(D), Record);
3026
3027  if (FunctionDecl *Function = dyn_cast<FunctionDecl>(Other))
3028    return isInstantiationOf(cast<FunctionDecl>(D), Function);
3029
3030  if (EnumDecl *Enum = dyn_cast<EnumDecl>(Other))
3031    return isInstantiationOf(cast<EnumDecl>(D), Enum);
3032
3033  if (VarDecl *Var = dyn_cast<VarDecl>(Other))
3034    if (Var->isStaticDataMember())
3035      return isInstantiationOfStaticDataMember(cast<VarDecl>(D), Var);
3036
3037  if (ClassTemplateDecl *Temp = dyn_cast<ClassTemplateDecl>(Other))
3038    return isInstantiationOf(cast<ClassTemplateDecl>(D), Temp);
3039
3040  if (FunctionTemplateDecl *Temp = dyn_cast<FunctionTemplateDecl>(Other))
3041    return isInstantiationOf(cast<FunctionTemplateDecl>(D), Temp);
3042
3043  if (ClassTemplatePartialSpecializationDecl *PartialSpec
3044        = dyn_cast<ClassTemplatePartialSpecializationDecl>(Other))
3045    return isInstantiationOf(cast<ClassTemplatePartialSpecializationDecl>(D),
3046                             PartialSpec);
3047
3048  if (FieldDecl *Field = dyn_cast<FieldDecl>(Other)) {
3049    if (!Field->getDeclName()) {
3050      // This is an unnamed field.
3051      return Ctx.getInstantiatedFromUnnamedFieldDecl(Field) ==
3052        cast<FieldDecl>(D);
3053    }
3054  }
3055
3056  if (UsingDecl *Using = dyn_cast<UsingDecl>(Other))
3057    return isInstantiationOf(cast<UsingDecl>(D), Using, Ctx);
3058
3059  if (UsingShadowDecl *Shadow = dyn_cast<UsingShadowDecl>(Other))
3060    return isInstantiationOf(cast<UsingShadowDecl>(D), Shadow, Ctx);
3061
3062  return D->getDeclName() && isa<NamedDecl>(Other) &&
3063    D->getDeclName() == cast<NamedDecl>(Other)->getDeclName();
3064}
3065
3066template<typename ForwardIterator>
3067static NamedDecl *findInstantiationOf(ASTContext &Ctx,
3068                                      NamedDecl *D,
3069                                      ForwardIterator first,
3070                                      ForwardIterator last) {
3071  for (; first != last; ++first)
3072    if (isInstantiationOf(Ctx, D, *first))
3073      return cast<NamedDecl>(*first);
3074
3075  return 0;
3076}
3077
3078/// \brief Finds the instantiation of the given declaration context
3079/// within the current instantiation.
3080///
3081/// \returns NULL if there was an error
3082DeclContext *Sema::FindInstantiatedContext(SourceLocation Loc, DeclContext* DC,
3083                          const MultiLevelTemplateArgumentList &TemplateArgs) {
3084  if (NamedDecl *D = dyn_cast<NamedDecl>(DC)) {
3085    Decl* ID = FindInstantiatedDecl(Loc, D, TemplateArgs);
3086    return cast_or_null<DeclContext>(ID);
3087  } else return DC;
3088}
3089
3090/// \brief Find the instantiation of the given declaration within the
3091/// current instantiation.
3092///
3093/// This routine is intended to be used when \p D is a declaration
3094/// referenced from within a template, that needs to mapped into the
3095/// corresponding declaration within an instantiation. For example,
3096/// given:
3097///
3098/// \code
3099/// template<typename T>
3100/// struct X {
3101///   enum Kind {
3102///     KnownValue = sizeof(T)
3103///   };
3104///
3105///   bool getKind() const { return KnownValue; }
3106/// };
3107///
3108/// template struct X<int>;
3109/// \endcode
3110///
3111/// In the instantiation of X<int>::getKind(), we need to map the
3112/// EnumConstantDecl for KnownValue (which refers to
3113/// X<T>::<Kind>::KnownValue) to its instantiation
3114/// (X<int>::<Kind>::KnownValue). InstantiateCurrentDeclRef() performs
3115/// this mapping from within the instantiation of X<int>.
3116NamedDecl *Sema::FindInstantiatedDecl(SourceLocation Loc, NamedDecl *D,
3117                          const MultiLevelTemplateArgumentList &TemplateArgs) {
3118  DeclContext *ParentDC = D->getDeclContext();
3119  if (isa<ParmVarDecl>(D) || isa<NonTypeTemplateParmDecl>(D) ||
3120      isa<TemplateTypeParmDecl>(D) || isa<TemplateTemplateParmDecl>(D) ||
3121      (ParentDC->isFunctionOrMethod() && ParentDC->isDependentContext())) {
3122    // D is a local of some kind. Look into the map of local
3123    // declarations to their instantiations.
3124    typedef LocalInstantiationScope::DeclArgumentPack DeclArgumentPack;
3125    llvm::PointerUnion<Decl *, DeclArgumentPack *> *Found
3126      = CurrentInstantiationScope->findInstantiationOf(D);
3127
3128    if (Found) {
3129      if (Decl *FD = Found->dyn_cast<Decl *>())
3130        return cast<NamedDecl>(FD);
3131
3132      unsigned PackIdx = ArgumentPackSubstitutionIndex;
3133      return cast<NamedDecl>((*Found->get<DeclArgumentPack *>())[PackIdx]);
3134    }
3135
3136    // If we didn't find the decl, then we must have a label decl that hasn't
3137    // been found yet.  Lazily instantiate it and return it now.
3138    assert(isa<LabelDecl>(D));
3139
3140    Decl *Inst = SubstDecl(D, CurContext, TemplateArgs);
3141    assert(Inst && "Failed to instantiate label??");
3142
3143    CurrentInstantiationScope->InstantiatedLocal(D, Inst);
3144    return cast<LabelDecl>(Inst);
3145  }
3146
3147  if (CXXRecordDecl *Record = dyn_cast<CXXRecordDecl>(D)) {
3148    if (!Record->isDependentContext())
3149      return D;
3150
3151    // If the RecordDecl is actually the injected-class-name or a
3152    // "templated" declaration for a class template, class template
3153    // partial specialization, or a member class of a class template,
3154    // substitute into the injected-class-name of the class template
3155    // or partial specialization to find the new DeclContext.
3156    QualType T;
3157    ClassTemplateDecl *ClassTemplate = Record->getDescribedClassTemplate();
3158
3159    if (ClassTemplate) {
3160      T = ClassTemplate->getInjectedClassNameSpecialization();
3161    } else if (ClassTemplatePartialSpecializationDecl *PartialSpec
3162                 = dyn_cast<ClassTemplatePartialSpecializationDecl>(Record)) {
3163      ClassTemplate = PartialSpec->getSpecializedTemplate();
3164
3165      // If we call SubstType with an InjectedClassNameType here we
3166      // can end up in an infinite loop.
3167      T = Context.getTypeDeclType(Record);
3168      assert(isa<InjectedClassNameType>(T) &&
3169             "type of partial specialization is not an InjectedClassNameType");
3170      T = cast<InjectedClassNameType>(T)->getInjectedSpecializationType();
3171    }
3172
3173    if (!T.isNull()) {
3174      // Substitute into the injected-class-name to get the type
3175      // corresponding to the instantiation we want, which may also be
3176      // the current instantiation (if we're in a template
3177      // definition). This substitution should never fail, since we
3178      // know we can instantiate the injected-class-name or we
3179      // wouldn't have gotten to the injected-class-name!
3180
3181      // FIXME: Can we use the CurrentInstantiationScope to avoid this
3182      // extra instantiation in the common case?
3183      T = SubstType(T, TemplateArgs, Loc, DeclarationName());
3184      assert(!T.isNull() && "Instantiation of injected-class-name cannot fail.");
3185
3186      if (!T->isDependentType()) {
3187        assert(T->isRecordType() && "Instantiation must produce a record type");
3188        return T->getAs<RecordType>()->getDecl();
3189      }
3190
3191      // We are performing "partial" template instantiation to create
3192      // the member declarations for the members of a class template
3193      // specialization. Therefore, D is actually referring to something
3194      // in the current instantiation. Look through the current
3195      // context, which contains actual instantiations, to find the
3196      // instantiation of the "current instantiation" that D refers
3197      // to.
3198      bool SawNonDependentContext = false;
3199      for (DeclContext *DC = CurContext; !DC->isFileContext();
3200           DC = DC->getParent()) {
3201        if (ClassTemplateSpecializationDecl *Spec
3202                          = dyn_cast<ClassTemplateSpecializationDecl>(DC))
3203          if (isInstantiationOf(ClassTemplate,
3204                                Spec->getSpecializedTemplate()))
3205            return Spec;
3206
3207        if (!DC->isDependentContext())
3208          SawNonDependentContext = true;
3209      }
3210
3211      // We're performing "instantiation" of a member of the current
3212      // instantiation while we are type-checking the
3213      // definition. Compute the declaration context and return that.
3214      assert(!SawNonDependentContext &&
3215             "No dependent context while instantiating record");
3216      DeclContext *DC = computeDeclContext(T);
3217      assert(DC &&
3218             "Unable to find declaration for the current instantiation");
3219      return cast<CXXRecordDecl>(DC);
3220    }
3221
3222    // Fall through to deal with other dependent record types (e.g.,
3223    // anonymous unions in class templates).
3224  }
3225
3226  if (!ParentDC->isDependentContext())
3227    return D;
3228
3229  ParentDC = FindInstantiatedContext(Loc, ParentDC, TemplateArgs);
3230  if (!ParentDC)
3231    return 0;
3232
3233  if (ParentDC != D->getDeclContext()) {
3234    // We performed some kind of instantiation in the parent context,
3235    // so now we need to look into the instantiated parent context to
3236    // find the instantiation of the declaration D.
3237
3238    // If our context used to be dependent, we may need to instantiate
3239    // it before performing lookup into that context.
3240    bool IsBeingInstantiated = false;
3241    if (CXXRecordDecl *Spec = dyn_cast<CXXRecordDecl>(ParentDC)) {
3242      if (!Spec->isDependentContext()) {
3243        QualType T = Context.getTypeDeclType(Spec);
3244        const RecordType *Tag = T->getAs<RecordType>();
3245        assert(Tag && "type of non-dependent record is not a RecordType");
3246        if (Tag->isBeingDefined())
3247          IsBeingInstantiated = true;
3248        if (!Tag->isBeingDefined() &&
3249            RequireCompleteType(Loc, T, diag::err_incomplete_type))
3250          return 0;
3251
3252        ParentDC = Tag->getDecl();
3253      }
3254    }
3255
3256    NamedDecl *Result = 0;
3257    if (D->getDeclName()) {
3258      DeclContext::lookup_result Found = ParentDC->lookup(D->getDeclName());
3259      Result = findInstantiationOf(Context, D, Found.first, Found.second);
3260    } else {
3261      // Since we don't have a name for the entity we're looking for,
3262      // our only option is to walk through all of the declarations to
3263      // find that name. This will occur in a few cases:
3264      //
3265      //   - anonymous struct/union within a template
3266      //   - unnamed class/struct/union/enum within a template
3267      //
3268      // FIXME: Find a better way to find these instantiations!
3269      Result = findInstantiationOf(Context, D,
3270                                   ParentDC->decls_begin(),
3271                                   ParentDC->decls_end());
3272    }
3273
3274    if (!Result) {
3275      if (isa<UsingShadowDecl>(D)) {
3276        // UsingShadowDecls can instantiate to nothing because of using hiding.
3277      } else if (Diags.hasErrorOccurred()) {
3278        // We've already complained about something, so most likely this
3279        // declaration failed to instantiate. There's no point in complaining
3280        // further, since this is normal in invalid code.
3281      } else if (IsBeingInstantiated) {
3282        // The class in which this member exists is currently being
3283        // instantiated, and we haven't gotten around to instantiating this
3284        // member yet. This can happen when the code uses forward declarations
3285        // of member classes, and introduces ordering dependencies via
3286        // template instantiation.
3287        Diag(Loc, diag::err_member_not_yet_instantiated)
3288          << D->getDeclName()
3289          << Context.getTypeDeclType(cast<CXXRecordDecl>(ParentDC));
3290        Diag(D->getLocation(), diag::note_non_instantiated_member_here);
3291      } else {
3292        // We should have found something, but didn't.
3293        llvm_unreachable("Unable to find instantiation of declaration!");
3294      }
3295    }
3296
3297    D = Result;
3298  }
3299
3300  return D;
3301}
3302
3303/// \brief Performs template instantiation for all implicit template
3304/// instantiations we have seen until this point.
3305void Sema::PerformPendingInstantiations(bool LocalOnly) {
3306  // Load pending instantiations from the external source.
3307  if (!LocalOnly && ExternalSource) {
3308    SmallVector<std::pair<ValueDecl *, SourceLocation>, 4> Pending;
3309    ExternalSource->ReadPendingInstantiations(Pending);
3310    PendingInstantiations.insert(PendingInstantiations.begin(),
3311                                 Pending.begin(), Pending.end());
3312  }
3313
3314  while (!PendingLocalImplicitInstantiations.empty() ||
3315         (!LocalOnly && !PendingInstantiations.empty())) {
3316    PendingImplicitInstantiation Inst;
3317
3318    if (PendingLocalImplicitInstantiations.empty()) {
3319      Inst = PendingInstantiations.front();
3320      PendingInstantiations.pop_front();
3321    } else {
3322      Inst = PendingLocalImplicitInstantiations.front();
3323      PendingLocalImplicitInstantiations.pop_front();
3324    }
3325
3326    // Instantiate function definitions
3327    if (FunctionDecl *Function = dyn_cast<FunctionDecl>(Inst.first)) {
3328      PrettyDeclStackTraceEntry CrashInfo(*this, Function, SourceLocation(),
3329                                          "instantiating function definition");
3330      bool DefinitionRequired = Function->getTemplateSpecializationKind() ==
3331                                TSK_ExplicitInstantiationDefinition;
3332      InstantiateFunctionDefinition(/*FIXME:*/Inst.second, Function, true,
3333                                    DefinitionRequired);
3334      continue;
3335    }
3336
3337    // Instantiate static data member definitions.
3338    VarDecl *Var = cast<VarDecl>(Inst.first);
3339    assert(Var->isStaticDataMember() && "Not a static data member?");
3340
3341    // Don't try to instantiate declarations if the most recent redeclaration
3342    // is invalid.
3343    if (Var->getMostRecentDeclaration()->isInvalidDecl())
3344      continue;
3345
3346    // Check if the most recent declaration has changed the specialization kind
3347    // and removed the need for implicit instantiation.
3348    switch (Var->getMostRecentDeclaration()->getTemplateSpecializationKind()) {
3349    case TSK_Undeclared:
3350      llvm_unreachable("Cannot instantitiate an undeclared specialization.");
3351    case TSK_ExplicitInstantiationDeclaration:
3352    case TSK_ExplicitSpecialization:
3353      continue;  // No longer need to instantiate this type.
3354    case TSK_ExplicitInstantiationDefinition:
3355      // We only need an instantiation if the pending instantiation *is* the
3356      // explicit instantiation.
3357      if (Var != Var->getMostRecentDeclaration()) continue;
3358    case TSK_ImplicitInstantiation:
3359      break;
3360    }
3361
3362    PrettyDeclStackTraceEntry CrashInfo(*this, Var, Var->getLocation(),
3363                                        "instantiating static data member "
3364                                        "definition");
3365
3366    bool DefinitionRequired = Var->getTemplateSpecializationKind() ==
3367                              TSK_ExplicitInstantiationDefinition;
3368    InstantiateStaticDataMemberDefinition(/*FIXME:*/Inst.second, Var, true,
3369                                          DefinitionRequired);
3370  }
3371}
3372
3373void Sema::PerformDependentDiagnostics(const DeclContext *Pattern,
3374                       const MultiLevelTemplateArgumentList &TemplateArgs) {
3375  for (DeclContext::ddiag_iterator I = Pattern->ddiag_begin(),
3376         E = Pattern->ddiag_end(); I != E; ++I) {
3377    DependentDiagnostic *DD = *I;
3378
3379    switch (DD->getKind()) {
3380    case DependentDiagnostic::Access:
3381      HandleDependentAccessCheck(*DD, TemplateArgs);
3382      break;
3383    }
3384  }
3385}
3386