SemaTemplateInstantiateDecl.cpp revision e994624c001143ee2b8a7a4715aaad5efcd71f18 
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 = SubstFunctionType(D, Params);
1042  if (!TInfo)
1043    return 0;
1044  QualType T = TInfo->getType();
1045
1046  NestedNameSpecifierLoc QualifierLoc = D->getQualifierLoc();
1047  if (QualifierLoc) {
1048    QualifierLoc = SemaRef.SubstNestedNameSpecifierLoc(QualifierLoc,
1049                                                       TemplateArgs);
1050    if (!QualifierLoc)
1051      return 0;
1052  }
1053
1054  // If we're instantiating a local function declaration, put the result
1055  // in the owner;  otherwise we need to find the instantiated context.
1056  DeclContext *DC;
1057  if (D->getDeclContext()->isFunctionOrMethod())
1058    DC = Owner;
1059  else if (isFriend && QualifierLoc) {
1060    CXXScopeSpec SS;
1061    SS.Adopt(QualifierLoc);
1062    DC = SemaRef.computeDeclContext(SS);
1063    if (!DC) return 0;
1064  } else {
1065    DC = SemaRef.FindInstantiatedContext(D->getLocation(), D->getDeclContext(),
1066                                         TemplateArgs);
1067  }
1068
1069  FunctionDecl *Function =
1070      FunctionDecl::Create(SemaRef.Context, DC, D->getInnerLocStart(),
1071                           D->getLocation(), D->getDeclName(), T, TInfo,
1072                           D->getStorageClass(), D->getStorageClassAsWritten(),
1073                           D->isInlineSpecified(), D->hasWrittenPrototype(),
1074                           /*isConstexpr*/ false);
1075
1076  if (QualifierLoc)
1077    Function->setQualifierInfo(QualifierLoc);
1078
1079  DeclContext *LexicalDC = Owner;
1080  if (!isFriend && D->isOutOfLine()) {
1081    assert(D->getDeclContext()->isFileContext());
1082    LexicalDC = D->getDeclContext();
1083  }
1084
1085  Function->setLexicalDeclContext(LexicalDC);
1086
1087  // Attach the parameters
1088  if (isa<FunctionProtoType>(Function->getType().IgnoreParens())) {
1089    // Adopt the already-instantiated parameters into our own context.
1090    for (unsigned P = 0; P < Params.size(); ++P)
1091      if (Params[P])
1092        Params[P]->setOwningFunction(Function);
1093  } else {
1094    // Since we were instantiated via a typedef of a function type, create
1095    // new parameters.
1096    const FunctionProtoType *Proto
1097      = Function->getType()->getAs<FunctionProtoType>();
1098    assert(Proto && "No function prototype in template instantiation?");
1099    for (FunctionProtoType::arg_type_iterator AI = Proto->arg_type_begin(),
1100         AE = Proto->arg_type_end(); AI != AE; ++AI) {
1101      ParmVarDecl *Param
1102        = SemaRef.BuildParmVarDeclForTypedef(Function, Function->getLocation(),
1103                                             *AI);
1104      Param->setScopeInfo(0, Params.size());
1105      Params.push_back(Param);
1106    }
1107  }
1108  Function->setParams(Params);
1109
1110  SourceLocation InstantiateAtPOI;
1111  if (TemplateParams) {
1112    // Our resulting instantiation is actually a function template, since we
1113    // are substituting only the outer template parameters. For example, given
1114    //
1115    //   template<typename T>
1116    //   struct X {
1117    //     template<typename U> friend void f(T, U);
1118    //   };
1119    //
1120    //   X<int> x;
1121    //
1122    // We are instantiating the friend function template "f" within X<int>,
1123    // which means substituting int for T, but leaving "f" as a friend function
1124    // template.
1125    // Build the function template itself.
1126    FunctionTemplate = FunctionTemplateDecl::Create(SemaRef.Context, DC,
1127                                                    Function->getLocation(),
1128                                                    Function->getDeclName(),
1129                                                    TemplateParams, Function);
1130    Function->setDescribedFunctionTemplate(FunctionTemplate);
1131
1132    FunctionTemplate->setLexicalDeclContext(LexicalDC);
1133
1134    if (isFriend && D->isThisDeclarationADefinition()) {
1135      // TODO: should we remember this connection regardless of whether
1136      // the friend declaration provided a body?
1137      FunctionTemplate->setInstantiatedFromMemberTemplate(
1138                                           D->getDescribedFunctionTemplate());
1139    }
1140  } else if (FunctionTemplate) {
1141    // Record this function template specialization.
1142    std::pair<const TemplateArgument *, unsigned> Innermost
1143      = TemplateArgs.getInnermost();
1144    Function->setFunctionTemplateSpecialization(FunctionTemplate,
1145                            TemplateArgumentList::CreateCopy(SemaRef.Context,
1146                                                             Innermost.first,
1147                                                             Innermost.second),
1148                                                InsertPos);
1149  } else if (isFriend) {
1150    // Note, we need this connection even if the friend doesn't have a body.
1151    // Its body may exist but not have been attached yet due to deferred
1152    // parsing.
1153    // FIXME: It might be cleaner to set this when attaching the body to the
1154    // friend function declaration, however that would require finding all the
1155    // instantiations and modifying them.
1156    Function->setInstantiationOfMemberFunction(D, TSK_ImplicitInstantiation);
1157  }
1158
1159  if (InitFunctionInstantiation(Function, D))
1160    Function->setInvalidDecl();
1161
1162  bool isExplicitSpecialization = false;
1163
1164  LookupResult Previous(SemaRef, Function->getDeclName(), SourceLocation(),
1165                        Sema::LookupOrdinaryName, Sema::ForRedeclaration);
1166
1167  if (DependentFunctionTemplateSpecializationInfo *Info
1168        = D->getDependentSpecializationInfo()) {
1169    assert(isFriend && "non-friend has dependent specialization info?");
1170
1171    // This needs to be set now for future sanity.
1172    Function->setObjectOfFriendDecl(/*HasPrevious*/ true);
1173
1174    // Instantiate the explicit template arguments.
1175    TemplateArgumentListInfo ExplicitArgs(Info->getLAngleLoc(),
1176                                          Info->getRAngleLoc());
1177    if (SemaRef.Subst(Info->getTemplateArgs(), Info->getNumTemplateArgs(),
1178                      ExplicitArgs, TemplateArgs))
1179      return 0;
1180
1181    // Map the candidate templates to their instantiations.
1182    for (unsigned I = 0, E = Info->getNumTemplates(); I != E; ++I) {
1183      Decl *Temp = SemaRef.FindInstantiatedDecl(D->getLocation(),
1184                                                Info->getTemplate(I),
1185                                                TemplateArgs);
1186      if (!Temp) return 0;
1187
1188      Previous.addDecl(cast<FunctionTemplateDecl>(Temp));
1189    }
1190
1191    if (SemaRef.CheckFunctionTemplateSpecialization(Function,
1192                                                    &ExplicitArgs,
1193                                                    Previous))
1194      Function->setInvalidDecl();
1195
1196    isExplicitSpecialization = true;
1197
1198  } else if (TemplateParams || !FunctionTemplate) {
1199    // Look only into the namespace where the friend would be declared to
1200    // find a previous declaration. This is the innermost enclosing namespace,
1201    // as described in ActOnFriendFunctionDecl.
1202    SemaRef.LookupQualifiedName(Previous, DC);
1203
1204    // In C++, the previous declaration we find might be a tag type
1205    // (class or enum). In this case, the new declaration will hide the
1206    // tag type. Note that this does does not apply if we're declaring a
1207    // typedef (C++ [dcl.typedef]p4).
1208    if (Previous.isSingleTagDecl())
1209      Previous.clear();
1210  }
1211
1212  SemaRef.CheckFunctionDeclaration(/*Scope*/ 0, Function, Previous,
1213                                   isExplicitSpecialization);
1214
1215  NamedDecl *PrincipalDecl = (TemplateParams
1216                              ? cast<NamedDecl>(FunctionTemplate)
1217                              : Function);
1218
1219  // If the original function was part of a friend declaration,
1220  // inherit its namespace state and add it to the owner.
1221  if (isFriend) {
1222    NamedDecl *PrevDecl;
1223    if (TemplateParams)
1224      PrevDecl = FunctionTemplate->getPreviousDeclaration();
1225    else
1226      PrevDecl = Function->getPreviousDeclaration();
1227
1228    PrincipalDecl->setObjectOfFriendDecl(PrevDecl != 0);
1229    DC->makeDeclVisibleInContext(PrincipalDecl, /*Recoverable=*/ false);
1230
1231    bool queuedInstantiation = false;
1232
1233    // C++98 [temp.friend]p5: When a function is defined in a friend function
1234    //   declaration in a class template, the function is defined at each
1235    //   instantiation of the class template. The function is defined even if it
1236    //   is never used.
1237    // C++11 [temp.friend]p4: When a function is defined in a friend function
1238    //   declaration in a class template, the function is instantiated when the
1239    //   function is odr-used.
1240    //
1241    // If -Wc++98-compat is enabled, we go through the motions of checking for a
1242    // redefinition, but don't instantiate the function.
1243    if ((!SemaRef.getLangOptions().CPlusPlus0x ||
1244         SemaRef.Diags.getDiagnosticLevel(
1245             diag::warn_cxx98_compat_friend_redefinition,
1246             Function->getLocation())
1247           != DiagnosticsEngine::Ignored) &&
1248        D->isThisDeclarationADefinition()) {
1249      // Check for a function body.
1250      const FunctionDecl *Definition = 0;
1251      if (Function->isDefined(Definition) &&
1252          Definition->getTemplateSpecializationKind() == TSK_Undeclared) {
1253        SemaRef.Diag(Function->getLocation(),
1254                     SemaRef.getLangOptions().CPlusPlus0x ?
1255                       diag::warn_cxx98_compat_friend_redefinition :
1256                       diag::err_redefinition) << Function->getDeclName();
1257        SemaRef.Diag(Definition->getLocation(), diag::note_previous_definition);
1258        if (!SemaRef.getLangOptions().CPlusPlus0x)
1259          Function->setInvalidDecl();
1260      }
1261      // Check for redefinitions due to other instantiations of this or
1262      // a similar friend function.
1263      else for (FunctionDecl::redecl_iterator R = Function->redecls_begin(),
1264                                           REnd = Function->redecls_end();
1265                R != REnd; ++R) {
1266        if (*R == Function)
1267          continue;
1268        switch (R->getFriendObjectKind()) {
1269        case Decl::FOK_None:
1270          if (!SemaRef.getLangOptions().CPlusPlus0x &&
1271              !queuedInstantiation && R->isUsed(false)) {
1272            if (MemberSpecializationInfo *MSInfo
1273                = Function->getMemberSpecializationInfo()) {
1274              if (MSInfo->getPointOfInstantiation().isInvalid()) {
1275                SourceLocation Loc = R->getLocation(); // FIXME
1276                MSInfo->setPointOfInstantiation(Loc);
1277                SemaRef.PendingLocalImplicitInstantiations.push_back(
1278                                                 std::make_pair(Function, Loc));
1279                queuedInstantiation = true;
1280              }
1281            }
1282          }
1283          break;
1284        default:
1285          if (const FunctionDecl *RPattern
1286              = R->getTemplateInstantiationPattern())
1287            if (RPattern->isDefined(RPattern)) {
1288              SemaRef.Diag(Function->getLocation(),
1289                           SemaRef.getLangOptions().CPlusPlus0x ?
1290                             diag::warn_cxx98_compat_friend_redefinition :
1291                             diag::err_redefinition)
1292                << Function->getDeclName();
1293              SemaRef.Diag(R->getLocation(), diag::note_previous_definition);
1294              if (!SemaRef.getLangOptions().CPlusPlus0x)
1295                Function->setInvalidDecl();
1296              break;
1297            }
1298        }
1299      }
1300    }
1301  }
1302
1303  if (Function->isOverloadedOperator() && !DC->isRecord() &&
1304      PrincipalDecl->isInIdentifierNamespace(Decl::IDNS_Ordinary))
1305    PrincipalDecl->setNonMemberOperator();
1306
1307  assert(!D->isDefaulted() && "only methods should be defaulted");
1308  return Function;
1309}
1310
1311Decl *
1312TemplateDeclInstantiator::VisitCXXMethodDecl(CXXMethodDecl *D,
1313                                      TemplateParameterList *TemplateParams,
1314                                      bool IsClassScopeSpecialization) {
1315  FunctionTemplateDecl *FunctionTemplate = D->getDescribedFunctionTemplate();
1316  void *InsertPos = 0;
1317  if (FunctionTemplate && !TemplateParams) {
1318    // We are creating a function template specialization from a function
1319    // template. Check whether there is already a function template
1320    // specialization for this particular set of template arguments.
1321    std::pair<const TemplateArgument *, unsigned> Innermost
1322      = TemplateArgs.getInnermost();
1323
1324    FunctionDecl *SpecFunc
1325      = FunctionTemplate->findSpecialization(Innermost.first, Innermost.second,
1326                                             InsertPos);
1327
1328    // If we already have a function template specialization, return it.
1329    if (SpecFunc)
1330      return SpecFunc;
1331  }
1332
1333  bool isFriend;
1334  if (FunctionTemplate)
1335    isFriend = (FunctionTemplate->getFriendObjectKind() != Decl::FOK_None);
1336  else
1337    isFriend = (D->getFriendObjectKind() != Decl::FOK_None);
1338
1339  bool MergeWithParentScope = (TemplateParams != 0) ||
1340    !(isa<Decl>(Owner) &&
1341      cast<Decl>(Owner)->isDefinedOutsideFunctionOrMethod());
1342  LocalInstantiationScope Scope(SemaRef, MergeWithParentScope);
1343
1344  // Instantiate enclosing template arguments for friends.
1345  SmallVector<TemplateParameterList *, 4> TempParamLists;
1346  unsigned NumTempParamLists = 0;
1347  if (isFriend && (NumTempParamLists = D->getNumTemplateParameterLists())) {
1348    TempParamLists.set_size(NumTempParamLists);
1349    for (unsigned I = 0; I != NumTempParamLists; ++I) {
1350      TemplateParameterList *TempParams = D->getTemplateParameterList(I);
1351      TemplateParameterList *InstParams = SubstTemplateParams(TempParams);
1352      if (!InstParams)
1353        return NULL;
1354      TempParamLists[I] = InstParams;
1355    }
1356  }
1357
1358  SmallVector<ParmVarDecl *, 4> Params;
1359  TypeSourceInfo *TInfo = D->getTypeSourceInfo();
1360  TInfo = SubstFunctionType(D, Params);
1361  if (!TInfo)
1362    return 0;
1363  QualType T = TInfo->getType();
1364
1365  // \brief If the type of this function, after ignoring parentheses,
1366  // is not *directly* a function type, then we're instantiating a function
1367  // that was declared via a typedef, e.g.,
1368  //
1369  //   typedef int functype(int, int);
1370  //   functype func;
1371  //
1372  // In this case, we'll just go instantiate the ParmVarDecls that we
1373  // synthesized in the method declaration.
1374  if (!isa<FunctionProtoType>(T.IgnoreParens())) {
1375    assert(!Params.size() && "Instantiating type could not yield parameters");
1376    SmallVector<QualType, 4> ParamTypes;
1377    if (SemaRef.SubstParmTypes(D->getLocation(), D->param_begin(),
1378                               D->getNumParams(), TemplateArgs, ParamTypes,
1379                               &Params))
1380      return 0;
1381  }
1382
1383  NestedNameSpecifierLoc QualifierLoc = D->getQualifierLoc();
1384  if (QualifierLoc) {
1385    QualifierLoc = SemaRef.SubstNestedNameSpecifierLoc(QualifierLoc,
1386                                                 TemplateArgs);
1387    if (!QualifierLoc)
1388      return 0;
1389  }
1390
1391  DeclContext *DC = Owner;
1392  if (isFriend) {
1393    if (QualifierLoc) {
1394      CXXScopeSpec SS;
1395      SS.Adopt(QualifierLoc);
1396      DC = SemaRef.computeDeclContext(SS);
1397
1398      if (DC && SemaRef.RequireCompleteDeclContext(SS, DC))
1399        return 0;
1400    } else {
1401      DC = SemaRef.FindInstantiatedContext(D->getLocation(),
1402                                           D->getDeclContext(),
1403                                           TemplateArgs);
1404    }
1405    if (!DC) return 0;
1406  }
1407
1408  // Build the instantiated method declaration.
1409  CXXRecordDecl *Record = cast<CXXRecordDecl>(DC);
1410  CXXMethodDecl *Method = 0;
1411
1412  SourceLocation StartLoc = D->getInnerLocStart();
1413  DeclarationNameInfo NameInfo
1414    = SemaRef.SubstDeclarationNameInfo(D->getNameInfo(), TemplateArgs);
1415  if (CXXConstructorDecl *Constructor = dyn_cast<CXXConstructorDecl>(D)) {
1416    Method = CXXConstructorDecl::Create(SemaRef.Context, Record,
1417                                        StartLoc, NameInfo, T, TInfo,
1418                                        Constructor->isExplicit(),
1419                                        Constructor->isInlineSpecified(),
1420                                        false, /*isConstexpr*/ false);
1421  } else if (CXXDestructorDecl *Destructor = dyn_cast<CXXDestructorDecl>(D)) {
1422    Method = CXXDestructorDecl::Create(SemaRef.Context, Record,
1423                                       StartLoc, NameInfo, T, TInfo,
1424                                       Destructor->isInlineSpecified(),
1425                                       false);
1426  } else if (CXXConversionDecl *Conversion = dyn_cast<CXXConversionDecl>(D)) {
1427    Method = CXXConversionDecl::Create(SemaRef.Context, Record,
1428                                       StartLoc, NameInfo, T, TInfo,
1429                                       Conversion->isInlineSpecified(),
1430                                       Conversion->isExplicit(),
1431                                       /*isConstexpr*/ false,
1432                                       Conversion->getLocEnd());
1433  } else {
1434    Method = CXXMethodDecl::Create(SemaRef.Context, Record,
1435                                   StartLoc, NameInfo, T, TInfo,
1436                                   D->isStatic(),
1437                                   D->getStorageClassAsWritten(),
1438                                   D->isInlineSpecified(),
1439                                   /*isConstexpr*/ false, D->getLocEnd());
1440  }
1441
1442  if (QualifierLoc)
1443    Method->setQualifierInfo(QualifierLoc);
1444
1445  if (TemplateParams) {
1446    // Our resulting instantiation is actually a function template, since we
1447    // are substituting only the outer template parameters. For example, given
1448    //
1449    //   template<typename T>
1450    //   struct X {
1451    //     template<typename U> void f(T, U);
1452    //   };
1453    //
1454    //   X<int> x;
1455    //
1456    // We are instantiating the member template "f" within X<int>, which means
1457    // substituting int for T, but leaving "f" as a member function template.
1458    // Build the function template itself.
1459    FunctionTemplate = FunctionTemplateDecl::Create(SemaRef.Context, Record,
1460                                                    Method->getLocation(),
1461                                                    Method->getDeclName(),
1462                                                    TemplateParams, Method);
1463    if (isFriend) {
1464      FunctionTemplate->setLexicalDeclContext(Owner);
1465      FunctionTemplate->setObjectOfFriendDecl(true);
1466    } else if (D->isOutOfLine())
1467      FunctionTemplate->setLexicalDeclContext(D->getLexicalDeclContext());
1468    Method->setDescribedFunctionTemplate(FunctionTemplate);
1469  } else if (FunctionTemplate) {
1470    // Record this function template specialization.
1471    std::pair<const TemplateArgument *, unsigned> Innermost
1472      = TemplateArgs.getInnermost();
1473    Method->setFunctionTemplateSpecialization(FunctionTemplate,
1474                         TemplateArgumentList::CreateCopy(SemaRef.Context,
1475                                                          Innermost.first,
1476                                                          Innermost.second),
1477                                              InsertPos);
1478  } else if (!isFriend) {
1479    // Record that this is an instantiation of a member function.
1480    Method->setInstantiationOfMemberFunction(D, TSK_ImplicitInstantiation);
1481  }
1482
1483  // If we are instantiating a member function defined
1484  // out-of-line, the instantiation will have the same lexical
1485  // context (which will be a namespace scope) as the template.
1486  if (isFriend) {
1487    if (NumTempParamLists)
1488      Method->setTemplateParameterListsInfo(SemaRef.Context,
1489                                            NumTempParamLists,
1490                                            TempParamLists.data());
1491
1492    Method->setLexicalDeclContext(Owner);
1493    Method->setObjectOfFriendDecl(true);
1494  } else if (D->isOutOfLine())
1495    Method->setLexicalDeclContext(D->getLexicalDeclContext());
1496
1497  // Attach the parameters
1498  for (unsigned P = 0; P < Params.size(); ++P)
1499    Params[P]->setOwningFunction(Method);
1500  Method->setParams(Params);
1501
1502  if (InitMethodInstantiation(Method, D))
1503    Method->setInvalidDecl();
1504
1505  LookupResult Previous(SemaRef, NameInfo, Sema::LookupOrdinaryName,
1506                        Sema::ForRedeclaration);
1507
1508  if (!FunctionTemplate || TemplateParams || isFriend) {
1509    SemaRef.LookupQualifiedName(Previous, Record);
1510
1511    // In C++, the previous declaration we find might be a tag type
1512    // (class or enum). In this case, the new declaration will hide the
1513    // tag type. Note that this does does not apply if we're declaring a
1514    // typedef (C++ [dcl.typedef]p4).
1515    if (Previous.isSingleTagDecl())
1516      Previous.clear();
1517  }
1518
1519  if (!IsClassScopeSpecialization)
1520    SemaRef.CheckFunctionDeclaration(0, Method, Previous, false);
1521
1522  if (D->isPure())
1523    SemaRef.CheckPureMethod(Method, SourceRange());
1524
1525  Method->setAccess(D->getAccess());
1526
1527  SemaRef.CheckOverrideControl(Method);
1528
1529  // If a function is defined as defaulted or deleted, mark it as such now.
1530  if (D->isDefaulted())
1531    Method->setDefaulted();
1532  if (D->isDeletedAsWritten())
1533    Method->setDeletedAsWritten();
1534
1535  if (FunctionTemplate) {
1536    // If there's a function template, let our caller handle it.
1537  } else if (Method->isInvalidDecl() && !Previous.empty()) {
1538    // Don't hide a (potentially) valid declaration with an invalid one.
1539  } else {
1540    NamedDecl *DeclToAdd = (TemplateParams
1541                            ? cast<NamedDecl>(FunctionTemplate)
1542                            : Method);
1543    if (isFriend)
1544      Record->makeDeclVisibleInContext(DeclToAdd);
1545    else if (!IsClassScopeSpecialization)
1546      Owner->addDecl(DeclToAdd);
1547  }
1548
1549  if (D->isExplicitlyDefaulted()) {
1550    SemaRef.SetDeclDefaulted(Method, Method->getLocation());
1551  } else {
1552    assert(!D->isDefaulted() &&
1553           "should not implicitly default uninstantiated function");
1554  }
1555
1556  return Method;
1557}
1558
1559Decl *TemplateDeclInstantiator::VisitCXXConstructorDecl(CXXConstructorDecl *D) {
1560  return VisitCXXMethodDecl(D);
1561}
1562
1563Decl *TemplateDeclInstantiator::VisitCXXDestructorDecl(CXXDestructorDecl *D) {
1564  return VisitCXXMethodDecl(D);
1565}
1566
1567Decl *TemplateDeclInstantiator::VisitCXXConversionDecl(CXXConversionDecl *D) {
1568  return VisitCXXMethodDecl(D);
1569}
1570
1571ParmVarDecl *TemplateDeclInstantiator::VisitParmVarDecl(ParmVarDecl *D) {
1572  return SemaRef.SubstParmVarDecl(D, TemplateArgs, /*indexAdjustment*/ 0,
1573                                  llvm::Optional<unsigned>());
1574}
1575
1576Decl *TemplateDeclInstantiator::VisitTemplateTypeParmDecl(
1577                                                    TemplateTypeParmDecl *D) {
1578  // TODO: don't always clone when decls are refcounted.
1579  assert(D->getTypeForDecl()->isTemplateTypeParmType());
1580
1581  TemplateTypeParmDecl *Inst =
1582    TemplateTypeParmDecl::Create(SemaRef.Context, Owner,
1583                                 D->getLocStart(), D->getLocation(),
1584                                 D->getDepth() - TemplateArgs.getNumLevels(),
1585                                 D->getIndex(), D->getIdentifier(),
1586                                 D->wasDeclaredWithTypename(),
1587                                 D->isParameterPack());
1588  Inst->setAccess(AS_public);
1589
1590  if (D->hasDefaultArgument())
1591    Inst->setDefaultArgument(D->getDefaultArgumentInfo(), false);
1592
1593  // Introduce this template parameter's instantiation into the instantiation
1594  // scope.
1595  SemaRef.CurrentInstantiationScope->InstantiatedLocal(D, Inst);
1596
1597  return Inst;
1598}
1599
1600Decl *TemplateDeclInstantiator::VisitNonTypeTemplateParmDecl(
1601                                                 NonTypeTemplateParmDecl *D) {
1602  // Substitute into the type of the non-type template parameter.
1603  TypeLoc TL = D->getTypeSourceInfo()->getTypeLoc();
1604  SmallVector<TypeSourceInfo *, 4> ExpandedParameterPackTypesAsWritten;
1605  SmallVector<QualType, 4> ExpandedParameterPackTypes;
1606  bool IsExpandedParameterPack = false;
1607  TypeSourceInfo *DI;
1608  QualType T;
1609  bool Invalid = false;
1610
1611  if (D->isExpandedParameterPack()) {
1612    // The non-type template parameter pack is an already-expanded pack
1613    // expansion of types. Substitute into each of the expanded types.
1614    ExpandedParameterPackTypes.reserve(D->getNumExpansionTypes());
1615    ExpandedParameterPackTypesAsWritten.reserve(D->getNumExpansionTypes());
1616    for (unsigned I = 0, N = D->getNumExpansionTypes(); I != N; ++I) {
1617      TypeSourceInfo *NewDI =SemaRef.SubstType(D->getExpansionTypeSourceInfo(I),
1618                                               TemplateArgs,
1619                                               D->getLocation(),
1620                                               D->getDeclName());
1621      if (!NewDI)
1622        return 0;
1623
1624      ExpandedParameterPackTypesAsWritten.push_back(NewDI);
1625      QualType NewT =SemaRef.CheckNonTypeTemplateParameterType(NewDI->getType(),
1626                                                              D->getLocation());
1627      if (NewT.isNull())
1628        return 0;
1629      ExpandedParameterPackTypes.push_back(NewT);
1630    }
1631
1632    IsExpandedParameterPack = true;
1633    DI = D->getTypeSourceInfo();
1634    T = DI->getType();
1635  } else if (isa<PackExpansionTypeLoc>(TL)) {
1636    // The non-type template parameter pack's type is a pack expansion of types.
1637    // Determine whether we need to expand this parameter pack into separate
1638    // types.
1639    PackExpansionTypeLoc Expansion = cast<PackExpansionTypeLoc>(TL);
1640    TypeLoc Pattern = Expansion.getPatternLoc();
1641    SmallVector<UnexpandedParameterPack, 2> Unexpanded;
1642    SemaRef.collectUnexpandedParameterPacks(Pattern, Unexpanded);
1643
1644    // Determine whether the set of unexpanded parameter packs can and should
1645    // be expanded.
1646    bool Expand = true;
1647    bool RetainExpansion = false;
1648    llvm::Optional<unsigned> OrigNumExpansions
1649      = Expansion.getTypePtr()->getNumExpansions();
1650    llvm::Optional<unsigned> NumExpansions = OrigNumExpansions;
1651    if (SemaRef.CheckParameterPacksForExpansion(Expansion.getEllipsisLoc(),
1652                                                Pattern.getSourceRange(),
1653                                                Unexpanded,
1654                                                TemplateArgs,
1655                                                Expand, RetainExpansion,
1656                                                NumExpansions))
1657      return 0;
1658
1659    if (Expand) {
1660      for (unsigned I = 0; I != *NumExpansions; ++I) {
1661        Sema::ArgumentPackSubstitutionIndexRAII SubstIndex(SemaRef, I);
1662        TypeSourceInfo *NewDI = SemaRef.SubstType(Pattern, TemplateArgs,
1663                                                  D->getLocation(),
1664                                                  D->getDeclName());
1665        if (!NewDI)
1666          return 0;
1667
1668        ExpandedParameterPackTypesAsWritten.push_back(NewDI);
1669        QualType NewT = SemaRef.CheckNonTypeTemplateParameterType(
1670                                                              NewDI->getType(),
1671                                                              D->getLocation());
1672        if (NewT.isNull())
1673          return 0;
1674        ExpandedParameterPackTypes.push_back(NewT);
1675      }
1676
1677      // Note that we have an expanded parameter pack. The "type" of this
1678      // expanded parameter pack is the original expansion type, but callers
1679      // will end up using the expanded parameter pack types for type-checking.
1680      IsExpandedParameterPack = true;
1681      DI = D->getTypeSourceInfo();
1682      T = DI->getType();
1683    } else {
1684      // We cannot fully expand the pack expansion now, so substitute into the
1685      // pattern and create a new pack expansion type.
1686      Sema::ArgumentPackSubstitutionIndexRAII SubstIndex(SemaRef, -1);
1687      TypeSourceInfo *NewPattern = SemaRef.SubstType(Pattern, TemplateArgs,
1688                                                     D->getLocation(),
1689                                                     D->getDeclName());
1690      if (!NewPattern)
1691        return 0;
1692
1693      DI = SemaRef.CheckPackExpansion(NewPattern, Expansion.getEllipsisLoc(),
1694                                      NumExpansions);
1695      if (!DI)
1696        return 0;
1697
1698      T = DI->getType();
1699    }
1700  } else {
1701    // Simple case: substitution into a parameter that is not a parameter pack.
1702    DI = SemaRef.SubstType(D->getTypeSourceInfo(), TemplateArgs,
1703                           D->getLocation(), D->getDeclName());
1704    if (!DI)
1705      return 0;
1706
1707    // Check that this type is acceptable for a non-type template parameter.
1708    T = SemaRef.CheckNonTypeTemplateParameterType(DI->getType(),
1709                                                  D->getLocation());
1710    if (T.isNull()) {
1711      T = SemaRef.Context.IntTy;
1712      Invalid = true;
1713    }
1714  }
1715
1716  NonTypeTemplateParmDecl *Param;
1717  if (IsExpandedParameterPack)
1718    Param = NonTypeTemplateParmDecl::Create(SemaRef.Context, Owner,
1719                                            D->getInnerLocStart(),
1720                                            D->getLocation(),
1721                                    D->getDepth() - TemplateArgs.getNumLevels(),
1722                                            D->getPosition(),
1723                                            D->getIdentifier(), T,
1724                                            DI,
1725                                            ExpandedParameterPackTypes.data(),
1726                                            ExpandedParameterPackTypes.size(),
1727                                    ExpandedParameterPackTypesAsWritten.data());
1728  else
1729    Param = NonTypeTemplateParmDecl::Create(SemaRef.Context, Owner,
1730                                            D->getInnerLocStart(),
1731                                            D->getLocation(),
1732                                    D->getDepth() - TemplateArgs.getNumLevels(),
1733                                            D->getPosition(),
1734                                            D->getIdentifier(), T,
1735                                            D->isParameterPack(), DI);
1736
1737  Param->setAccess(AS_public);
1738  if (Invalid)
1739    Param->setInvalidDecl();
1740
1741  Param->setDefaultArgument(D->getDefaultArgument(), false);
1742
1743  // Introduce this template parameter's instantiation into the instantiation
1744  // scope.
1745  SemaRef.CurrentInstantiationScope->InstantiatedLocal(D, Param);
1746  return Param;
1747}
1748
1749Decl *
1750TemplateDeclInstantiator::VisitTemplateTemplateParmDecl(
1751                                                  TemplateTemplateParmDecl *D) {
1752  // Instantiate the template parameter list of the template template parameter.
1753  TemplateParameterList *TempParams = D->getTemplateParameters();
1754  TemplateParameterList *InstParams;
1755  {
1756    // Perform the actual substitution of template parameters within a new,
1757    // local instantiation scope.
1758    LocalInstantiationScope Scope(SemaRef);
1759    InstParams = SubstTemplateParams(TempParams);
1760    if (!InstParams)
1761      return NULL;
1762  }
1763
1764  // Build the template template parameter.
1765  TemplateTemplateParmDecl *Param
1766    = TemplateTemplateParmDecl::Create(SemaRef.Context, Owner, D->getLocation(),
1767                                   D->getDepth() - TemplateArgs.getNumLevels(),
1768                                       D->getPosition(), D->isParameterPack(),
1769                                       D->getIdentifier(), InstParams);
1770  Param->setDefaultArgument(D->getDefaultArgument(), false);
1771  Param->setAccess(AS_public);
1772
1773  // Introduce this template parameter's instantiation into the instantiation
1774  // scope.
1775  SemaRef.CurrentInstantiationScope->InstantiatedLocal(D, Param);
1776
1777  return Param;
1778}
1779
1780Decl *TemplateDeclInstantiator::VisitUsingDirectiveDecl(UsingDirectiveDecl *D) {
1781  // Using directives are never dependent (and never contain any types or
1782  // expressions), so they require no explicit instantiation work.
1783
1784  UsingDirectiveDecl *Inst
1785    = UsingDirectiveDecl::Create(SemaRef.Context, Owner, D->getLocation(),
1786                                 D->getNamespaceKeyLocation(),
1787                                 D->getQualifierLoc(),
1788                                 D->getIdentLocation(),
1789                                 D->getNominatedNamespace(),
1790                                 D->getCommonAncestor());
1791  Owner->addDecl(Inst);
1792  return Inst;
1793}
1794
1795Decl *TemplateDeclInstantiator::VisitUsingDecl(UsingDecl *D) {
1796
1797  // The nested name specifier may be dependent, for example
1798  //     template <typename T> struct t {
1799  //       struct s1 { T f1(); };
1800  //       struct s2 : s1 { using s1::f1; };
1801  //     };
1802  //     template struct t<int>;
1803  // Here, in using s1::f1, s1 refers to t<T>::s1;
1804  // we need to substitute for t<int>::s1.
1805  NestedNameSpecifierLoc QualifierLoc
1806    = SemaRef.SubstNestedNameSpecifierLoc(D->getQualifierLoc(),
1807                                          TemplateArgs);
1808  if (!QualifierLoc)
1809    return 0;
1810
1811  // The name info is non-dependent, so no transformation
1812  // is required.
1813  DeclarationNameInfo NameInfo = D->getNameInfo();
1814
1815  // We only need to do redeclaration lookups if we're in a class
1816  // scope (in fact, it's not really even possible in non-class
1817  // scopes).
1818  bool CheckRedeclaration = Owner->isRecord();
1819
1820  LookupResult Prev(SemaRef, NameInfo, Sema::LookupUsingDeclName,
1821                    Sema::ForRedeclaration);
1822
1823  UsingDecl *NewUD = UsingDecl::Create(SemaRef.Context, Owner,
1824                                       D->getUsingLocation(),
1825                                       QualifierLoc,
1826                                       NameInfo,
1827                                       D->isTypeName());
1828
1829  CXXScopeSpec SS;
1830  SS.Adopt(QualifierLoc);
1831  if (CheckRedeclaration) {
1832    Prev.setHideTags(false);
1833    SemaRef.LookupQualifiedName(Prev, Owner);
1834
1835    // Check for invalid redeclarations.
1836    if (SemaRef.CheckUsingDeclRedeclaration(D->getUsingLocation(),
1837                                            D->isTypeName(), SS,
1838                                            D->getLocation(), Prev))
1839      NewUD->setInvalidDecl();
1840
1841  }
1842
1843  if (!NewUD->isInvalidDecl() &&
1844      SemaRef.CheckUsingDeclQualifier(D->getUsingLocation(), SS,
1845                                      D->getLocation()))
1846    NewUD->setInvalidDecl();
1847
1848  SemaRef.Context.setInstantiatedFromUsingDecl(NewUD, D);
1849  NewUD->setAccess(D->getAccess());
1850  Owner->addDecl(NewUD);
1851
1852  // Don't process the shadow decls for an invalid decl.
1853  if (NewUD->isInvalidDecl())
1854    return NewUD;
1855
1856  bool isFunctionScope = Owner->isFunctionOrMethod();
1857
1858  // Process the shadow decls.
1859  for (UsingDecl::shadow_iterator I = D->shadow_begin(), E = D->shadow_end();
1860         I != E; ++I) {
1861    UsingShadowDecl *Shadow = *I;
1862    NamedDecl *InstTarget =
1863      cast_or_null<NamedDecl>(SemaRef.FindInstantiatedDecl(
1864                                                          Shadow->getLocation(),
1865                                                        Shadow->getTargetDecl(),
1866                                                           TemplateArgs));
1867    if (!InstTarget)
1868      return 0;
1869
1870    if (CheckRedeclaration &&
1871        SemaRef.CheckUsingShadowDecl(NewUD, InstTarget, Prev))
1872      continue;
1873
1874    UsingShadowDecl *InstShadow
1875      = SemaRef.BuildUsingShadowDecl(/*Scope*/ 0, NewUD, InstTarget);
1876    SemaRef.Context.setInstantiatedFromUsingShadowDecl(InstShadow, Shadow);
1877
1878    if (isFunctionScope)
1879      SemaRef.CurrentInstantiationScope->InstantiatedLocal(Shadow, InstShadow);
1880  }
1881
1882  return NewUD;
1883}
1884
1885Decl *TemplateDeclInstantiator::VisitUsingShadowDecl(UsingShadowDecl *D) {
1886  // Ignore these;  we handle them in bulk when processing the UsingDecl.
1887  return 0;
1888}
1889
1890Decl * TemplateDeclInstantiator
1891    ::VisitUnresolvedUsingTypenameDecl(UnresolvedUsingTypenameDecl *D) {
1892  NestedNameSpecifierLoc QualifierLoc
1893    = SemaRef.SubstNestedNameSpecifierLoc(D->getQualifierLoc(),
1894                                          TemplateArgs);
1895  if (!QualifierLoc)
1896    return 0;
1897
1898  CXXScopeSpec SS;
1899  SS.Adopt(QualifierLoc);
1900
1901  // Since NameInfo refers to a typename, it cannot be a C++ special name.
1902  // Hence, no tranformation is required for it.
1903  DeclarationNameInfo NameInfo(D->getDeclName(), D->getLocation());
1904  NamedDecl *UD =
1905    SemaRef.BuildUsingDeclaration(/*Scope*/ 0, D->getAccess(),
1906                                  D->getUsingLoc(), SS, NameInfo, 0,
1907                                  /*instantiation*/ true,
1908                                  /*typename*/ true, D->getTypenameLoc());
1909  if (UD)
1910    SemaRef.Context.setInstantiatedFromUsingDecl(cast<UsingDecl>(UD), D);
1911
1912  return UD;
1913}
1914
1915Decl * TemplateDeclInstantiator
1916    ::VisitUnresolvedUsingValueDecl(UnresolvedUsingValueDecl *D) {
1917  NestedNameSpecifierLoc QualifierLoc
1918      = SemaRef.SubstNestedNameSpecifierLoc(D->getQualifierLoc(), TemplateArgs);
1919  if (!QualifierLoc)
1920    return 0;
1921
1922  CXXScopeSpec SS;
1923  SS.Adopt(QualifierLoc);
1924
1925  DeclarationNameInfo NameInfo
1926    = SemaRef.SubstDeclarationNameInfo(D->getNameInfo(), TemplateArgs);
1927
1928  NamedDecl *UD =
1929    SemaRef.BuildUsingDeclaration(/*Scope*/ 0, D->getAccess(),
1930                                  D->getUsingLoc(), SS, NameInfo, 0,
1931                                  /*instantiation*/ true,
1932                                  /*typename*/ false, SourceLocation());
1933  if (UD)
1934    SemaRef.Context.setInstantiatedFromUsingDecl(cast<UsingDecl>(UD), D);
1935
1936  return UD;
1937}
1938
1939
1940Decl *TemplateDeclInstantiator::VisitClassScopeFunctionSpecializationDecl(
1941                                     ClassScopeFunctionSpecializationDecl *Decl) {
1942  CXXMethodDecl *OldFD = Decl->getSpecialization();
1943  CXXMethodDecl *NewFD = cast<CXXMethodDecl>(VisitCXXMethodDecl(OldFD, 0, true));
1944
1945  LookupResult Previous(SemaRef, NewFD->getNameInfo(), Sema::LookupOrdinaryName,
1946                        Sema::ForRedeclaration);
1947
1948  SemaRef.LookupQualifiedName(Previous, SemaRef.CurContext);
1949  if (SemaRef.CheckFunctionTemplateSpecialization(NewFD, 0, Previous)) {
1950    NewFD->setInvalidDecl();
1951    return NewFD;
1952  }
1953
1954  // Associate the specialization with the pattern.
1955  FunctionDecl *Specialization = cast<FunctionDecl>(Previous.getFoundDecl());
1956  assert(Specialization && "Class scope Specialization is null");
1957  SemaRef.Context.setClassScopeSpecializationPattern(Specialization, OldFD);
1958
1959  return NewFD;
1960}
1961
1962Decl *Sema::SubstDecl(Decl *D, DeclContext *Owner,
1963                      const MultiLevelTemplateArgumentList &TemplateArgs) {
1964  TemplateDeclInstantiator Instantiator(*this, Owner, TemplateArgs);
1965  if (D->isInvalidDecl())
1966    return 0;
1967
1968  return Instantiator.Visit(D);
1969}
1970
1971/// \brief Instantiates a nested template parameter list in the current
1972/// instantiation context.
1973///
1974/// \param L The parameter list to instantiate
1975///
1976/// \returns NULL if there was an error
1977TemplateParameterList *
1978TemplateDeclInstantiator::SubstTemplateParams(TemplateParameterList *L) {
1979  // Get errors for all the parameters before bailing out.
1980  bool Invalid = false;
1981
1982  unsigned N = L->size();
1983  typedef SmallVector<NamedDecl *, 8> ParamVector;
1984  ParamVector Params;
1985  Params.reserve(N);
1986  for (TemplateParameterList::iterator PI = L->begin(), PE = L->end();
1987       PI != PE; ++PI) {
1988    NamedDecl *D = cast_or_null<NamedDecl>(Visit(*PI));
1989    Params.push_back(D);
1990    Invalid = Invalid || !D || D->isInvalidDecl();
1991  }
1992
1993  // Clean up if we had an error.
1994  if (Invalid)
1995    return NULL;
1996
1997  TemplateParameterList *InstL
1998    = TemplateParameterList::Create(SemaRef.Context, L->getTemplateLoc(),
1999                                    L->getLAngleLoc(), &Params.front(), N,
2000                                    L->getRAngleLoc());
2001  return InstL;
2002}
2003
2004/// \brief Instantiate the declaration of a class template partial
2005/// specialization.
2006///
2007/// \param ClassTemplate the (instantiated) class template that is partially
2008// specialized by the instantiation of \p PartialSpec.
2009///
2010/// \param PartialSpec the (uninstantiated) class template partial
2011/// specialization that we are instantiating.
2012///
2013/// \returns The instantiated partial specialization, if successful; otherwise,
2014/// NULL to indicate an error.
2015ClassTemplatePartialSpecializationDecl *
2016TemplateDeclInstantiator::InstantiateClassTemplatePartialSpecialization(
2017                                            ClassTemplateDecl *ClassTemplate,
2018                          ClassTemplatePartialSpecializationDecl *PartialSpec) {
2019  // Create a local instantiation scope for this class template partial
2020  // specialization, which will contain the instantiations of the template
2021  // parameters.
2022  LocalInstantiationScope Scope(SemaRef);
2023
2024  // Substitute into the template parameters of the class template partial
2025  // specialization.
2026  TemplateParameterList *TempParams = PartialSpec->getTemplateParameters();
2027  TemplateParameterList *InstParams = SubstTemplateParams(TempParams);
2028  if (!InstParams)
2029    return 0;
2030
2031  // Substitute into the template arguments of the class template partial
2032  // specialization.
2033  TemplateArgumentListInfo InstTemplateArgs; // no angle locations
2034  if (SemaRef.Subst(PartialSpec->getTemplateArgsAsWritten(),
2035                    PartialSpec->getNumTemplateArgsAsWritten(),
2036                    InstTemplateArgs, TemplateArgs))
2037    return 0;
2038
2039  // Check that the template argument list is well-formed for this
2040  // class template.
2041  SmallVector<TemplateArgument, 4> Converted;
2042  if (SemaRef.CheckTemplateArgumentList(ClassTemplate,
2043                                        PartialSpec->getLocation(),
2044                                        InstTemplateArgs,
2045                                        false,
2046                                        Converted))
2047    return 0;
2048
2049  // Figure out where to insert this class template partial specialization
2050  // in the member template's set of class template partial specializations.
2051  void *InsertPos = 0;
2052  ClassTemplateSpecializationDecl *PrevDecl
2053    = ClassTemplate->findPartialSpecialization(Converted.data(),
2054                                               Converted.size(), InsertPos);
2055
2056  // Build the canonical type that describes the converted template
2057  // arguments of the class template partial specialization.
2058  QualType CanonType
2059    = SemaRef.Context.getTemplateSpecializationType(TemplateName(ClassTemplate),
2060                                                    Converted.data(),
2061                                                    Converted.size());
2062
2063  // Build the fully-sugared type for this class template
2064  // specialization as the user wrote in the specialization
2065  // itself. This means that we'll pretty-print the type retrieved
2066  // from the specialization's declaration the way that the user
2067  // actually wrote the specialization, rather than formatting the
2068  // name based on the "canonical" representation used to store the
2069  // template arguments in the specialization.
2070  TypeSourceInfo *WrittenTy
2071    = SemaRef.Context.getTemplateSpecializationTypeInfo(
2072                                                    TemplateName(ClassTemplate),
2073                                                    PartialSpec->getLocation(),
2074                                                    InstTemplateArgs,
2075                                                    CanonType);
2076
2077  if (PrevDecl) {
2078    // We've already seen a partial specialization with the same template
2079    // parameters and template arguments. This can happen, for example, when
2080    // substituting the outer template arguments ends up causing two
2081    // class template partial specializations of a member class template
2082    // to have identical forms, e.g.,
2083    //
2084    //   template<typename T, typename U>
2085    //   struct Outer {
2086    //     template<typename X, typename Y> struct Inner;
2087    //     template<typename Y> struct Inner<T, Y>;
2088    //     template<typename Y> struct Inner<U, Y>;
2089    //   };
2090    //
2091    //   Outer<int, int> outer; // error: the partial specializations of Inner
2092    //                          // have the same signature.
2093    SemaRef.Diag(PartialSpec->getLocation(), diag::err_partial_spec_redeclared)
2094      << WrittenTy->getType();
2095    SemaRef.Diag(PrevDecl->getLocation(), diag::note_prev_partial_spec_here)
2096      << SemaRef.Context.getTypeDeclType(PrevDecl);
2097    return 0;
2098  }
2099
2100
2101  // Create the class template partial specialization declaration.
2102  ClassTemplatePartialSpecializationDecl *InstPartialSpec
2103    = ClassTemplatePartialSpecializationDecl::Create(SemaRef.Context,
2104                                                     PartialSpec->getTagKind(),
2105                                                     Owner,
2106                                                     PartialSpec->getLocStart(),
2107                                                     PartialSpec->getLocation(),
2108                                                     InstParams,
2109                                                     ClassTemplate,
2110                                                     Converted.data(),
2111                                                     Converted.size(),
2112                                                     InstTemplateArgs,
2113                                                     CanonType,
2114                                                     0,
2115                             ClassTemplate->getNextPartialSpecSequenceNumber());
2116  // Substitute the nested name specifier, if any.
2117  if (SubstQualifier(PartialSpec, InstPartialSpec))
2118    return 0;
2119
2120  InstPartialSpec->setInstantiatedFromMember(PartialSpec);
2121  InstPartialSpec->setTypeAsWritten(WrittenTy);
2122
2123  // Add this partial specialization to the set of class template partial
2124  // specializations.
2125  ClassTemplate->AddPartialSpecialization(InstPartialSpec, InsertPos);
2126  return InstPartialSpec;
2127}
2128
2129TypeSourceInfo*
2130TemplateDeclInstantiator::SubstFunctionType(FunctionDecl *D,
2131                              SmallVectorImpl<ParmVarDecl *> &Params) {
2132  TypeSourceInfo *OldTInfo = D->getTypeSourceInfo();
2133  assert(OldTInfo && "substituting function without type source info");
2134  assert(Params.empty() && "parameter vector is non-empty at start");
2135  TypeSourceInfo *NewTInfo
2136    = SemaRef.SubstFunctionDeclType(OldTInfo, TemplateArgs,
2137                                    D->getTypeSpecStartLoc(),
2138                                    D->getDeclName());
2139  if (!NewTInfo)
2140    return 0;
2141
2142  if (NewTInfo != OldTInfo) {
2143    // Get parameters from the new type info.
2144    TypeLoc OldTL = OldTInfo->getTypeLoc().IgnoreParens();
2145    if (FunctionProtoTypeLoc *OldProtoLoc
2146                                  = dyn_cast<FunctionProtoTypeLoc>(&OldTL)) {
2147      TypeLoc NewTL = NewTInfo->getTypeLoc().IgnoreParens();
2148      FunctionProtoTypeLoc *NewProtoLoc = cast<FunctionProtoTypeLoc>(&NewTL);
2149      assert(NewProtoLoc && "Missing prototype?");
2150      unsigned NewIdx = 0, NumNewParams = NewProtoLoc->getNumArgs();
2151      for (unsigned OldIdx = 0, NumOldParams = OldProtoLoc->getNumArgs();
2152           OldIdx != NumOldParams; ++OldIdx) {
2153        ParmVarDecl *OldParam = OldProtoLoc->getArg(OldIdx);
2154        if (!OldParam->isParameterPack() ||
2155            (NewIdx < NumNewParams &&
2156             NewProtoLoc->getArg(NewIdx)->isParameterPack())) {
2157          // Simple case: normal parameter, or a parameter pack that's
2158          // instantiated to a (still-dependent) parameter pack.
2159          ParmVarDecl *NewParam = NewProtoLoc->getArg(NewIdx++);
2160          Params.push_back(NewParam);
2161          SemaRef.CurrentInstantiationScope->InstantiatedLocal(OldParam,
2162                                                               NewParam);
2163          continue;
2164        }
2165
2166        // Parameter pack: make the instantiation an argument pack.
2167        SemaRef.CurrentInstantiationScope->MakeInstantiatedLocalArgPack(
2168                                                                      OldParam);
2169        unsigned NumArgumentsInExpansion
2170          = SemaRef.getNumArgumentsInExpansion(OldParam->getType(),
2171                                               TemplateArgs);
2172        while (NumArgumentsInExpansion--) {
2173          ParmVarDecl *NewParam = NewProtoLoc->getArg(NewIdx++);
2174          Params.push_back(NewParam);
2175          SemaRef.CurrentInstantiationScope->InstantiatedLocalPackArg(OldParam,
2176                                                                      NewParam);
2177        }
2178      }
2179    }
2180  } else {
2181    // The function type itself was not dependent and therefore no
2182    // substitution occurred. However, we still need to instantiate
2183    // the function parameters themselves.
2184    TypeLoc OldTL = OldTInfo->getTypeLoc().IgnoreParens();
2185    if (FunctionProtoTypeLoc *OldProtoLoc
2186                                    = dyn_cast<FunctionProtoTypeLoc>(&OldTL)) {
2187      for (unsigned i = 0, i_end = OldProtoLoc->getNumArgs(); i != i_end; ++i) {
2188        ParmVarDecl *Parm = VisitParmVarDecl(OldProtoLoc->getArg(i));
2189        if (!Parm)
2190          return 0;
2191        Params.push_back(Parm);
2192      }
2193    }
2194  }
2195  return NewTInfo;
2196}
2197
2198/// \brief Initializes the common fields of an instantiation function
2199/// declaration (New) from the corresponding fields of its template (Tmpl).
2200///
2201/// \returns true if there was an error
2202bool
2203TemplateDeclInstantiator::InitFunctionInstantiation(FunctionDecl *New,
2204                                                    FunctionDecl *Tmpl) {
2205  if (Tmpl->isDeletedAsWritten())
2206    New->setDeletedAsWritten();
2207
2208  // If we are performing substituting explicitly-specified template arguments
2209  // or deduced template arguments into a function template and we reach this
2210  // point, we are now past the point where SFINAE applies and have committed
2211  // to keeping the new function template specialization. We therefore
2212  // convert the active template instantiation for the function template
2213  // into a template instantiation for this specific function template
2214  // specialization, which is not a SFINAE context, so that we diagnose any
2215  // further errors in the declaration itself.
2216  typedef Sema::ActiveTemplateInstantiation ActiveInstType;
2217  ActiveInstType &ActiveInst = SemaRef.ActiveTemplateInstantiations.back();
2218  if (ActiveInst.Kind == ActiveInstType::ExplicitTemplateArgumentSubstitution ||
2219      ActiveInst.Kind == ActiveInstType::DeducedTemplateArgumentSubstitution) {
2220    if (FunctionTemplateDecl *FunTmpl
2221          = dyn_cast<FunctionTemplateDecl>((Decl *)ActiveInst.Entity)) {
2222      assert(FunTmpl->getTemplatedDecl() == Tmpl &&
2223             "Deduction from the wrong function template?");
2224      (void) FunTmpl;
2225      ActiveInst.Kind = ActiveInstType::TemplateInstantiation;
2226      ActiveInst.Entity = reinterpret_cast<uintptr_t>(New);
2227      --SemaRef.NonInstantiationEntries;
2228    }
2229  }
2230
2231  const FunctionProtoType *Proto = Tmpl->getType()->getAs<FunctionProtoType>();
2232  assert(Proto && "Function template without prototype?");
2233
2234  if (Proto->hasExceptionSpec() || Proto->getNoReturnAttr()) {
2235    // The function has an exception specification or a "noreturn"
2236    // attribute. Substitute into each of the exception types.
2237    SmallVector<QualType, 4> Exceptions;
2238    for (unsigned I = 0, N = Proto->getNumExceptions(); I != N; ++I) {
2239      // FIXME: Poor location information!
2240      if (const PackExpansionType *PackExpansion
2241            = Proto->getExceptionType(I)->getAs<PackExpansionType>()) {
2242        // We have a pack expansion. Instantiate it.
2243        SmallVector<UnexpandedParameterPack, 2> Unexpanded;
2244        SemaRef.collectUnexpandedParameterPacks(PackExpansion->getPattern(),
2245                                                Unexpanded);
2246        assert(!Unexpanded.empty() &&
2247               "Pack expansion without parameter packs?");
2248
2249        bool Expand = false;
2250        bool RetainExpansion = false;
2251        llvm::Optional<unsigned> NumExpansions
2252                                          = PackExpansion->getNumExpansions();
2253        if (SemaRef.CheckParameterPacksForExpansion(New->getLocation(),
2254                                                    SourceRange(),
2255                                                    Unexpanded,
2256                                                    TemplateArgs,
2257                                                    Expand,
2258                                                    RetainExpansion,
2259                                                    NumExpansions))
2260          break;
2261
2262        if (!Expand) {
2263          // We can't expand this pack expansion into separate arguments yet;
2264          // just substitute into the pattern and create a new pack expansion
2265          // type.
2266          Sema::ArgumentPackSubstitutionIndexRAII SubstIndex(SemaRef, -1);
2267          QualType T = SemaRef.SubstType(PackExpansion->getPattern(),
2268                                         TemplateArgs,
2269                                       New->getLocation(), New->getDeclName());
2270          if (T.isNull())
2271            break;
2272
2273          T = SemaRef.Context.getPackExpansionType(T, NumExpansions);
2274          Exceptions.push_back(T);
2275          continue;
2276        }
2277
2278        // Substitute into the pack expansion pattern for each template
2279        bool Invalid = false;
2280        for (unsigned ArgIdx = 0; ArgIdx != *NumExpansions; ++ArgIdx) {
2281          Sema::ArgumentPackSubstitutionIndexRAII SubstIndex(SemaRef, ArgIdx);
2282
2283          QualType T = SemaRef.SubstType(PackExpansion->getPattern(),
2284                                         TemplateArgs,
2285                                       New->getLocation(), New->getDeclName());
2286          if (T.isNull()) {
2287            Invalid = true;
2288            break;
2289          }
2290
2291          Exceptions.push_back(T);
2292        }
2293
2294        if (Invalid)
2295          break;
2296
2297        continue;
2298      }
2299
2300      QualType T
2301        = SemaRef.SubstType(Proto->getExceptionType(I), TemplateArgs,
2302                            New->getLocation(), New->getDeclName());
2303      if (T.isNull() ||
2304          SemaRef.CheckSpecifiedExceptionType(T, New->getLocation()))
2305        continue;
2306
2307      Exceptions.push_back(T);
2308    }
2309    Expr *NoexceptExpr = 0;
2310    if (Expr *OldNoexceptExpr = Proto->getNoexceptExpr()) {
2311      EnterExpressionEvaluationContext Unevaluated(SemaRef, Sema::Unevaluated);
2312      ExprResult E = SemaRef.SubstExpr(OldNoexceptExpr, TemplateArgs);
2313      if (E.isUsable())
2314        E = SemaRef.CheckBooleanCondition(E.get(), E.get()->getLocStart());
2315
2316      if (E.isUsable()) {
2317        SourceLocation ErrLoc;
2318        llvm::APSInt NoexceptVal;
2319        NoexceptExpr = E.take();
2320        if (!NoexceptExpr->isTypeDependent() &&
2321            !NoexceptExpr->isValueDependent() &&
2322            !NoexceptExpr->isIntegerConstantExpr(NoexceptVal, SemaRef.Context,
2323                                                 &ErrLoc, /*evaluated=*/false)){
2324          SemaRef.Diag(ErrLoc, diag::err_noexcept_needs_constant_expression)
2325            << NoexceptExpr->getSourceRange();
2326          NoexceptExpr = 0;
2327        }
2328      }
2329    }
2330
2331    // Rebuild the function type
2332
2333    FunctionProtoType::ExtProtoInfo EPI = Proto->getExtProtoInfo();
2334    EPI.ExceptionSpecType = Proto->getExceptionSpecType();
2335    EPI.NumExceptions = Exceptions.size();
2336    EPI.Exceptions = Exceptions.data();
2337    EPI.NoexceptExpr = NoexceptExpr;
2338    EPI.ExtInfo = Proto->getExtInfo();
2339
2340    const FunctionProtoType *NewProto
2341      = New->getType()->getAs<FunctionProtoType>();
2342    assert(NewProto && "Template instantiation without function prototype?");
2343    New->setType(SemaRef.Context.getFunctionType(NewProto->getResultType(),
2344                                                 NewProto->arg_type_begin(),
2345                                                 NewProto->getNumArgs(),
2346                                                 EPI));
2347  }
2348
2349  // C++0x [dcl.constexpr]p6: If the instantiated template specialization of
2350  // a constexpr function template satisfies the requirements for a constexpr
2351  // function, then it is a constexpr function.
2352  if (Tmpl->isConstexpr() &&
2353      SemaRef.CheckConstexprFunctionDecl(New, Sema::CCK_Instantiation))
2354    New->setConstexpr(true);
2355
2356  const FunctionDecl* Definition = Tmpl;
2357
2358  // Get the definition. Leaves the variable unchanged if undefined.
2359  Tmpl->isDefined(Definition);
2360
2361  SemaRef.InstantiateAttrs(TemplateArgs, Definition, New);
2362
2363  return false;
2364}
2365
2366/// \brief Initializes common fields of an instantiated method
2367/// declaration (New) from the corresponding fields of its template
2368/// (Tmpl).
2369///
2370/// \returns true if there was an error
2371bool
2372TemplateDeclInstantiator::InitMethodInstantiation(CXXMethodDecl *New,
2373                                                  CXXMethodDecl *Tmpl) {
2374  if (InitFunctionInstantiation(New, Tmpl))
2375    return true;
2376
2377  New->setAccess(Tmpl->getAccess());
2378  if (Tmpl->isVirtualAsWritten())
2379    New->setVirtualAsWritten(true);
2380
2381  // FIXME: attributes
2382  // FIXME: New needs a pointer to Tmpl
2383  return false;
2384}
2385
2386/// \brief Instantiate the definition of the given function from its
2387/// template.
2388///
2389/// \param PointOfInstantiation the point at which the instantiation was
2390/// required. Note that this is not precisely a "point of instantiation"
2391/// for the function, but it's close.
2392///
2393/// \param Function the already-instantiated declaration of a
2394/// function template specialization or member function of a class template
2395/// specialization.
2396///
2397/// \param Recursive if true, recursively instantiates any functions that
2398/// are required by this instantiation.
2399///
2400/// \param DefinitionRequired if true, then we are performing an explicit
2401/// instantiation where the body of the function is required. Complain if
2402/// there is no such body.
2403void Sema::InstantiateFunctionDefinition(SourceLocation PointOfInstantiation,
2404                                         FunctionDecl *Function,
2405                                         bool Recursive,
2406                                         bool DefinitionRequired) {
2407  if (Function->isInvalidDecl() || Function->isDefined())
2408    return;
2409
2410  // Never instantiate an explicit specialization except if it is a class scope
2411  // explicit specialization.
2412  if (Function->getTemplateSpecializationKind() == TSK_ExplicitSpecialization &&
2413      !Function->getClassScopeSpecializationPattern())
2414    return;
2415
2416  // Find the function body that we'll be substituting.
2417  const FunctionDecl *PatternDecl = Function->getTemplateInstantiationPattern();
2418  assert(PatternDecl && "instantiating a non-template");
2419
2420  Stmt *Pattern = PatternDecl->getBody(PatternDecl);
2421  assert(PatternDecl && "template definition is not a template");
2422  if (!Pattern) {
2423    // Try to find a defaulted definition
2424    PatternDecl->isDefined(PatternDecl);
2425  }
2426  assert(PatternDecl && "template definition is not a template");
2427
2428  // Postpone late parsed template instantiations.
2429  if (PatternDecl->isLateTemplateParsed() &&
2430      !LateTemplateParser) {
2431    PendingInstantiations.push_back(
2432      std::make_pair(Function, PointOfInstantiation));
2433    return;
2434  }
2435
2436  // Call the LateTemplateParser callback if there a need to late parse
2437  // a templated function definition.
2438  if (!Pattern && PatternDecl->isLateTemplateParsed() &&
2439      LateTemplateParser) {
2440    LateTemplateParser(OpaqueParser, PatternDecl);
2441    Pattern = PatternDecl->getBody(PatternDecl);
2442  }
2443
2444  if (!Pattern && !PatternDecl->isDefaulted()) {
2445    if (DefinitionRequired) {
2446      if (Function->getPrimaryTemplate())
2447        Diag(PointOfInstantiation,
2448             diag::err_explicit_instantiation_undefined_func_template)
2449          << Function->getPrimaryTemplate();
2450      else
2451        Diag(PointOfInstantiation,
2452             diag::err_explicit_instantiation_undefined_member)
2453          << 1 << Function->getDeclName() << Function->getDeclContext();
2454
2455      if (PatternDecl)
2456        Diag(PatternDecl->getLocation(),
2457             diag::note_explicit_instantiation_here);
2458      Function->setInvalidDecl();
2459    } else if (Function->getTemplateSpecializationKind()
2460                 == TSK_ExplicitInstantiationDefinition) {
2461      PendingInstantiations.push_back(
2462        std::make_pair(Function, PointOfInstantiation));
2463    }
2464
2465    return;
2466  }
2467
2468  // C++0x [temp.explicit]p9:
2469  //   Except for inline functions, other explicit instantiation declarations
2470  //   have the effect of suppressing the implicit instantiation of the entity
2471  //   to which they refer.
2472  if (Function->getTemplateSpecializationKind()
2473        == TSK_ExplicitInstantiationDeclaration &&
2474      !PatternDecl->isInlined())
2475    return;
2476
2477  InstantiatingTemplate Inst(*this, PointOfInstantiation, Function);
2478  if (Inst)
2479    return;
2480
2481  // Copy the inner loc start from the pattern.
2482  Function->setInnerLocStart(PatternDecl->getInnerLocStart());
2483
2484  // If we're performing recursive template instantiation, create our own
2485  // queue of pending implicit instantiations that we will instantiate later,
2486  // while we're still within our own instantiation context.
2487  SmallVector<VTableUse, 16> SavedVTableUses;
2488  std::deque<PendingImplicitInstantiation> SavedPendingInstantiations;
2489  if (Recursive) {
2490    VTableUses.swap(SavedVTableUses);
2491    PendingInstantiations.swap(SavedPendingInstantiations);
2492  }
2493
2494  EnterExpressionEvaluationContext EvalContext(*this,
2495                                               Sema::PotentiallyEvaluated);
2496  ActOnStartOfFunctionDef(0, Function);
2497
2498  // Introduce a new scope where local variable instantiations will be
2499  // recorded, unless we're actually a member function within a local
2500  // class, in which case we need to merge our results with the parent
2501  // scope (of the enclosing function).
2502  bool MergeWithParentScope = false;
2503  if (CXXRecordDecl *Rec = dyn_cast<CXXRecordDecl>(Function->getDeclContext()))
2504    MergeWithParentScope = Rec->isLocalClass();
2505
2506  LocalInstantiationScope Scope(*this, MergeWithParentScope);
2507
2508  // Introduce the instantiated function parameters into the local
2509  // instantiation scope, and set the parameter names to those used
2510  // in the template.
2511  unsigned FParamIdx = 0;
2512  for (unsigned I = 0, N = PatternDecl->getNumParams(); I != N; ++I) {
2513    const ParmVarDecl *PatternParam = PatternDecl->getParamDecl(I);
2514    if (!PatternParam->isParameterPack()) {
2515      // Simple case: not a parameter pack.
2516      assert(FParamIdx < Function->getNumParams());
2517      ParmVarDecl *FunctionParam = Function->getParamDecl(I);
2518      FunctionParam->setDeclName(PatternParam->getDeclName());
2519      Scope.InstantiatedLocal(PatternParam, FunctionParam);
2520      ++FParamIdx;
2521      continue;
2522    }
2523
2524    // Expand the parameter pack.
2525    Scope.MakeInstantiatedLocalArgPack(PatternParam);
2526    for (unsigned NumFParams = Function->getNumParams();
2527         FParamIdx < NumFParams;
2528         ++FParamIdx) {
2529      ParmVarDecl *FunctionParam = Function->getParamDecl(FParamIdx);
2530      FunctionParam->setDeclName(PatternParam->getDeclName());
2531      Scope.InstantiatedLocalPackArg(PatternParam, FunctionParam);
2532    }
2533  }
2534
2535  // Enter the scope of this instantiation. We don't use
2536  // PushDeclContext because we don't have a scope.
2537  Sema::ContextRAII savedContext(*this, Function);
2538
2539  MultiLevelTemplateArgumentList TemplateArgs =
2540    getTemplateInstantiationArgs(Function, 0, false, PatternDecl);
2541
2542  if (PatternDecl->isDefaulted()) {
2543    ActOnFinishFunctionBody(Function, 0, /*IsInstantiation=*/true);
2544
2545    SetDeclDefaulted(Function, PatternDecl->getLocation());
2546  } else {
2547    // If this is a constructor, instantiate the member initializers.
2548    if (const CXXConstructorDecl *Ctor =
2549          dyn_cast<CXXConstructorDecl>(PatternDecl)) {
2550      InstantiateMemInitializers(cast<CXXConstructorDecl>(Function), Ctor,
2551                                 TemplateArgs);
2552    }
2553
2554    // Instantiate the function body.
2555    StmtResult Body = SubstStmt(Pattern, TemplateArgs);
2556
2557    if (Body.isInvalid())
2558      Function->setInvalidDecl();
2559
2560    ActOnFinishFunctionBody(Function, Body.get(),
2561                            /*IsInstantiation=*/true);
2562  }
2563
2564  PerformDependentDiagnostics(PatternDecl, TemplateArgs);
2565
2566  savedContext.pop();
2567
2568  DeclGroupRef DG(Function);
2569  Consumer.HandleTopLevelDecl(DG);
2570
2571  // This class may have local implicit instantiations that need to be
2572  // instantiation within this scope.
2573  PerformPendingInstantiations(/*LocalOnly=*/true);
2574  Scope.Exit();
2575
2576  if (Recursive) {
2577    // Define any pending vtables.
2578    DefineUsedVTables();
2579
2580    // Instantiate any pending implicit instantiations found during the
2581    // instantiation of this template.
2582    PerformPendingInstantiations();
2583
2584    // Restore the set of pending vtables.
2585    assert(VTableUses.empty() &&
2586           "VTableUses should be empty before it is discarded.");
2587    VTableUses.swap(SavedVTableUses);
2588
2589    // Restore the set of pending implicit instantiations.
2590    assert(PendingInstantiations.empty() &&
2591           "PendingInstantiations should be empty before it is discarded.");
2592    PendingInstantiations.swap(SavedPendingInstantiations);
2593  }
2594}
2595
2596/// \brief Instantiate the definition of the given variable from its
2597/// template.
2598///
2599/// \param PointOfInstantiation the point at which the instantiation was
2600/// required. Note that this is not precisely a "point of instantiation"
2601/// for the function, but it's close.
2602///
2603/// \param Var the already-instantiated declaration of a static member
2604/// variable of a class template specialization.
2605///
2606/// \param Recursive if true, recursively instantiates any functions that
2607/// are required by this instantiation.
2608///
2609/// \param DefinitionRequired if true, then we are performing an explicit
2610/// instantiation where an out-of-line definition of the member variable
2611/// is required. Complain if there is no such definition.
2612void Sema::InstantiateStaticDataMemberDefinition(
2613                                          SourceLocation PointOfInstantiation,
2614                                                 VarDecl *Var,
2615                                                 bool Recursive,
2616                                                 bool DefinitionRequired) {
2617  if (Var->isInvalidDecl())
2618    return;
2619
2620  // Find the out-of-line definition of this static data member.
2621  VarDecl *Def = Var->getInstantiatedFromStaticDataMember();
2622  assert(Def && "This data member was not instantiated from a template?");
2623  assert(Def->isStaticDataMember() && "Not a static data member?");
2624  Def = Def->getOutOfLineDefinition();
2625
2626  if (!Def) {
2627    // We did not find an out-of-line definition of this static data member,
2628    // so we won't perform any instantiation. Rather, we rely on the user to
2629    // instantiate this definition (or provide a specialization for it) in
2630    // another translation unit.
2631    if (DefinitionRequired) {
2632      Def = Var->getInstantiatedFromStaticDataMember();
2633      Diag(PointOfInstantiation,
2634           diag::err_explicit_instantiation_undefined_member)
2635        << 2 << Var->getDeclName() << Var->getDeclContext();
2636      Diag(Def->getLocation(), diag::note_explicit_instantiation_here);
2637    } else if (Var->getTemplateSpecializationKind()
2638                 == TSK_ExplicitInstantiationDefinition) {
2639      PendingInstantiations.push_back(
2640        std::make_pair(Var, PointOfInstantiation));
2641    }
2642
2643    return;
2644  }
2645
2646  // Never instantiate an explicit specialization.
2647  if (Var->getTemplateSpecializationKind() == TSK_ExplicitSpecialization)
2648    return;
2649
2650  // C++0x [temp.explicit]p9:
2651  //   Except for inline functions, other explicit instantiation declarations
2652  //   have the effect of suppressing the implicit instantiation of the entity
2653  //   to which they refer.
2654  if (Var->getTemplateSpecializationKind()
2655        == TSK_ExplicitInstantiationDeclaration)
2656    return;
2657
2658  // If we already have a definition, we're done.
2659  if (Var->getDefinition())
2660    return;
2661
2662  InstantiatingTemplate Inst(*this, PointOfInstantiation, Var);
2663  if (Inst)
2664    return;
2665
2666  // If we're performing recursive template instantiation, create our own
2667  // queue of pending implicit instantiations that we will instantiate later,
2668  // while we're still within our own instantiation context.
2669  SmallVector<VTableUse, 16> SavedVTableUses;
2670  std::deque<PendingImplicitInstantiation> SavedPendingInstantiations;
2671  if (Recursive) {
2672    VTableUses.swap(SavedVTableUses);
2673    PendingInstantiations.swap(SavedPendingInstantiations);
2674  }
2675
2676  // Enter the scope of this instantiation. We don't use
2677  // PushDeclContext because we don't have a scope.
2678  ContextRAII previousContext(*this, Var->getDeclContext());
2679
2680  VarDecl *OldVar = Var;
2681  Var = cast_or_null<VarDecl>(SubstDecl(Def, Var->getDeclContext(),
2682                                        getTemplateInstantiationArgs(Var)));
2683
2684  previousContext.pop();
2685
2686  if (Var) {
2687    MemberSpecializationInfo *MSInfo = OldVar->getMemberSpecializationInfo();
2688    assert(MSInfo && "Missing member specialization information?");
2689    Var->setTemplateSpecializationKind(MSInfo->getTemplateSpecializationKind(),
2690                                       MSInfo->getPointOfInstantiation());
2691    DeclGroupRef DG(Var);
2692    Consumer.HandleTopLevelDecl(DG);
2693  }
2694
2695  if (Recursive) {
2696    // Define any newly required vtables.
2697    DefineUsedVTables();
2698
2699    // Instantiate any pending implicit instantiations found during the
2700    // instantiation of this template.
2701    PerformPendingInstantiations();
2702
2703    // Restore the set of pending vtables.
2704    assert(VTableUses.empty() &&
2705           "VTableUses should be empty before it is discarded, "
2706           "while instantiating static data member.");
2707    VTableUses.swap(SavedVTableUses);
2708
2709    // Restore the set of pending implicit instantiations.
2710    assert(PendingInstantiations.empty() &&
2711           "PendingInstantiations should be empty before it is discarded, "
2712           "while instantiating static data member.");
2713    PendingInstantiations.swap(SavedPendingInstantiations);
2714  }
2715}
2716
2717static MultiInitializer CreateMultiInitializer(SmallVectorImpl<Expr*> &Args,
2718                                               const CXXCtorInitializer *Init) {
2719  // FIXME: This is a hack that will do slightly the wrong thing for an
2720  // initializer of the form foo({...}).
2721  // The right thing to do would be to modify InstantiateInitializer to create
2722  // the MultiInitializer.
2723  if (Args.size() == 1 && isa<InitListExpr>(Args[0]))
2724    return MultiInitializer(Args[0]);
2725  return MultiInitializer(Init->getLParenLoc(), Args.data(),
2726                          Args.size(), Init->getRParenLoc());
2727}
2728
2729void
2730Sema::InstantiateMemInitializers(CXXConstructorDecl *New,
2731                                 const CXXConstructorDecl *Tmpl,
2732                           const MultiLevelTemplateArgumentList &TemplateArgs) {
2733
2734  SmallVector<CXXCtorInitializer*, 4> NewInits;
2735  bool AnyErrors = false;
2736
2737  // Instantiate all the initializers.
2738  for (CXXConstructorDecl::init_const_iterator Inits = Tmpl->init_begin(),
2739                                            InitsEnd = Tmpl->init_end();
2740       Inits != InitsEnd; ++Inits) {
2741    CXXCtorInitializer *Init = *Inits;
2742
2743    // Only instantiate written initializers, let Sema re-construct implicit
2744    // ones.
2745    if (!Init->isWritten())
2746      continue;
2747
2748    SourceLocation LParenLoc, RParenLoc;
2749    ASTOwningVector<Expr*> NewArgs(*this);
2750
2751    SourceLocation EllipsisLoc;
2752
2753    if (Init->isPackExpansion()) {
2754      // This is a pack expansion. We should expand it now.
2755      TypeLoc BaseTL = Init->getTypeSourceInfo()->getTypeLoc();
2756      SmallVector<UnexpandedParameterPack, 2> Unexpanded;
2757      collectUnexpandedParameterPacks(BaseTL, Unexpanded);
2758      bool ShouldExpand = false;
2759      bool RetainExpansion = false;
2760      llvm::Optional<unsigned> NumExpansions;
2761      if (CheckParameterPacksForExpansion(Init->getEllipsisLoc(),
2762                                          BaseTL.getSourceRange(),
2763                                          Unexpanded,
2764                                          TemplateArgs, ShouldExpand,
2765                                          RetainExpansion,
2766                                          NumExpansions)) {
2767        AnyErrors = true;
2768        New->setInvalidDecl();
2769        continue;
2770      }
2771      assert(ShouldExpand && "Partial instantiation of base initializer?");
2772
2773      // Loop over all of the arguments in the argument pack(s),
2774      for (unsigned I = 0; I != *NumExpansions; ++I) {
2775        Sema::ArgumentPackSubstitutionIndexRAII SubstIndex(*this, I);
2776
2777        // Instantiate the initializer.
2778        if (InstantiateInitializer(Init->getInit(), TemplateArgs,
2779                                   LParenLoc, NewArgs, RParenLoc)) {
2780          AnyErrors = true;
2781          break;
2782        }
2783
2784        // Instantiate the base type.
2785        TypeSourceInfo *BaseTInfo = SubstType(Init->getTypeSourceInfo(),
2786                                              TemplateArgs,
2787                                              Init->getSourceLocation(),
2788                                              New->getDeclName());
2789        if (!BaseTInfo) {
2790          AnyErrors = true;
2791          break;
2792        }
2793
2794        // Build the initializer.
2795        MultiInitializer MultiInit(CreateMultiInitializer(NewArgs, Init));
2796        MemInitResult NewInit = BuildBaseInitializer(BaseTInfo->getType(),
2797                                                     BaseTInfo, MultiInit,
2798                                                     New->getParent(),
2799                                                     SourceLocation());
2800        if (NewInit.isInvalid()) {
2801          AnyErrors = true;
2802          break;
2803        }
2804
2805        NewInits.push_back(NewInit.get());
2806        NewArgs.clear();
2807      }
2808
2809      continue;
2810    }
2811
2812    // Instantiate the initializer.
2813    if (InstantiateInitializer(Init->getInit(), TemplateArgs,
2814                               LParenLoc, NewArgs, RParenLoc)) {
2815      AnyErrors = true;
2816      continue;
2817    }
2818
2819    MemInitResult NewInit;
2820    if (Init->isDelegatingInitializer() || Init->isBaseInitializer()) {
2821      TypeSourceInfo *TInfo = SubstType(Init->getTypeSourceInfo(),
2822                                        TemplateArgs,
2823                                        Init->getSourceLocation(),
2824                                        New->getDeclName());
2825      if (!TInfo) {
2826        AnyErrors = true;
2827        New->setInvalidDecl();
2828        continue;
2829      }
2830
2831      MultiInitializer MultiInit(CreateMultiInitializer(NewArgs, Init));
2832
2833      if (Init->isBaseInitializer())
2834        NewInit = BuildBaseInitializer(TInfo->getType(), TInfo, MultiInit,
2835                                       New->getParent(), EllipsisLoc);
2836      else
2837        NewInit = BuildDelegatingInitializer(TInfo, MultiInit,
2838                                  cast<CXXRecordDecl>(CurContext->getParent()));
2839    } else if (Init->isMemberInitializer()) {
2840      FieldDecl *Member = cast_or_null<FieldDecl>(FindInstantiatedDecl(
2841                                                     Init->getMemberLocation(),
2842                                                     Init->getMember(),
2843                                                     TemplateArgs));
2844      if (!Member) {
2845        AnyErrors = true;
2846        New->setInvalidDecl();
2847        continue;
2848      }
2849
2850      MultiInitializer MultiInit(CreateMultiInitializer(NewArgs, Init));
2851      NewInit = BuildMemberInitializer(Member, MultiInit,
2852                                       Init->getSourceLocation());
2853    } else if (Init->isIndirectMemberInitializer()) {
2854      IndirectFieldDecl *IndirectMember =
2855         cast_or_null<IndirectFieldDecl>(FindInstantiatedDecl(
2856                                 Init->getMemberLocation(),
2857                                 Init->getIndirectMember(), TemplateArgs));
2858
2859      if (!IndirectMember) {
2860        AnyErrors = true;
2861        New->setInvalidDecl();
2862        continue;
2863      }
2864
2865      MultiInitializer MultiInit(CreateMultiInitializer(NewArgs, Init));
2866      NewInit = BuildMemberInitializer(IndirectMember, MultiInit,
2867                                       Init->getSourceLocation());
2868    }
2869
2870    if (NewInit.isInvalid()) {
2871      AnyErrors = true;
2872      New->setInvalidDecl();
2873    } else {
2874      // FIXME: It would be nice if ASTOwningVector had a release function.
2875      NewArgs.take();
2876
2877      NewInits.push_back(NewInit.get());
2878    }
2879  }
2880
2881  // Assign all the initializers to the new constructor.
2882  ActOnMemInitializers(New,
2883                       /*FIXME: ColonLoc */
2884                       SourceLocation(),
2885                       NewInits.data(), NewInits.size(),
2886                       AnyErrors);
2887}
2888
2889// TODO: this could be templated if the various decl types used the
2890// same method name.
2891static bool isInstantiationOf(ClassTemplateDecl *Pattern,
2892                              ClassTemplateDecl *Instance) {
2893  Pattern = Pattern->getCanonicalDecl();
2894
2895  do {
2896    Instance = Instance->getCanonicalDecl();
2897    if (Pattern == Instance) return true;
2898    Instance = Instance->getInstantiatedFromMemberTemplate();
2899  } while (Instance);
2900
2901  return false;
2902}
2903
2904static bool isInstantiationOf(FunctionTemplateDecl *Pattern,
2905                              FunctionTemplateDecl *Instance) {
2906  Pattern = Pattern->getCanonicalDecl();
2907
2908  do {
2909    Instance = Instance->getCanonicalDecl();
2910    if (Pattern == Instance) return true;
2911    Instance = Instance->getInstantiatedFromMemberTemplate();
2912  } while (Instance);
2913
2914  return false;
2915}
2916
2917static bool
2918isInstantiationOf(ClassTemplatePartialSpecializationDecl *Pattern,
2919                  ClassTemplatePartialSpecializationDecl *Instance) {
2920  Pattern
2921    = cast<ClassTemplatePartialSpecializationDecl>(Pattern->getCanonicalDecl());
2922  do {
2923    Instance = cast<ClassTemplatePartialSpecializationDecl>(
2924                                                Instance->getCanonicalDecl());
2925    if (Pattern == Instance)
2926      return true;
2927    Instance = Instance->getInstantiatedFromMember();
2928  } while (Instance);
2929
2930  return false;
2931}
2932
2933static bool isInstantiationOf(CXXRecordDecl *Pattern,
2934                              CXXRecordDecl *Instance) {
2935  Pattern = Pattern->getCanonicalDecl();
2936
2937  do {
2938    Instance = Instance->getCanonicalDecl();
2939    if (Pattern == Instance) return true;
2940    Instance = Instance->getInstantiatedFromMemberClass();
2941  } while (Instance);
2942
2943  return false;
2944}
2945
2946static bool isInstantiationOf(FunctionDecl *Pattern,
2947                              FunctionDecl *Instance) {
2948  Pattern = Pattern->getCanonicalDecl();
2949
2950  do {
2951    Instance = Instance->getCanonicalDecl();
2952    if (Pattern == Instance) return true;
2953    Instance = Instance->getInstantiatedFromMemberFunction();
2954  } while (Instance);
2955
2956  return false;
2957}
2958
2959static bool isInstantiationOf(EnumDecl *Pattern,
2960                              EnumDecl *Instance) {
2961  Pattern = Pattern->getCanonicalDecl();
2962
2963  do {
2964    Instance = Instance->getCanonicalDecl();
2965    if (Pattern == Instance) return true;
2966    Instance = Instance->getInstantiatedFromMemberEnum();
2967  } while (Instance);
2968
2969  return false;
2970}
2971
2972static bool isInstantiationOf(UsingShadowDecl *Pattern,
2973                              UsingShadowDecl *Instance,
2974                              ASTContext &C) {
2975  return C.getInstantiatedFromUsingShadowDecl(Instance) == Pattern;
2976}
2977
2978static bool isInstantiationOf(UsingDecl *Pattern,
2979                              UsingDecl *Instance,
2980                              ASTContext &C) {
2981  return C.getInstantiatedFromUsingDecl(Instance) == Pattern;
2982}
2983
2984static bool isInstantiationOf(UnresolvedUsingValueDecl *Pattern,
2985                              UsingDecl *Instance,
2986                              ASTContext &C) {
2987  return C.getInstantiatedFromUsingDecl(Instance) == Pattern;
2988}
2989
2990static bool isInstantiationOf(UnresolvedUsingTypenameDecl *Pattern,
2991                              UsingDecl *Instance,
2992                              ASTContext &C) {
2993  return C.getInstantiatedFromUsingDecl(Instance) == Pattern;
2994}
2995
2996static bool isInstantiationOfStaticDataMember(VarDecl *Pattern,
2997                                              VarDecl *Instance) {
2998  assert(Instance->isStaticDataMember());
2999
3000  Pattern = Pattern->getCanonicalDecl();
3001
3002  do {
3003    Instance = Instance->getCanonicalDecl();
3004    if (Pattern == Instance) return true;
3005    Instance = Instance->getInstantiatedFromStaticDataMember();
3006  } while (Instance);
3007
3008  return false;
3009}
3010
3011// Other is the prospective instantiation
3012// D is the prospective pattern
3013static bool isInstantiationOf(ASTContext &Ctx, NamedDecl *D, Decl *Other) {
3014  if (D->getKind() != Other->getKind()) {
3015    if (UnresolvedUsingTypenameDecl *UUD
3016          = dyn_cast<UnresolvedUsingTypenameDecl>(D)) {
3017      if (UsingDecl *UD = dyn_cast<UsingDecl>(Other)) {
3018        return isInstantiationOf(UUD, UD, Ctx);
3019      }
3020    }
3021
3022    if (UnresolvedUsingValueDecl *UUD
3023          = dyn_cast<UnresolvedUsingValueDecl>(D)) {
3024      if (UsingDecl *UD = dyn_cast<UsingDecl>(Other)) {
3025        return isInstantiationOf(UUD, UD, Ctx);
3026      }
3027    }
3028
3029    return false;
3030  }
3031
3032  if (CXXRecordDecl *Record = dyn_cast<CXXRecordDecl>(Other))
3033    return isInstantiationOf(cast<CXXRecordDecl>(D), Record);
3034
3035  if (FunctionDecl *Function = dyn_cast<FunctionDecl>(Other))
3036    return isInstantiationOf(cast<FunctionDecl>(D), Function);
3037
3038  if (EnumDecl *Enum = dyn_cast<EnumDecl>(Other))
3039    return isInstantiationOf(cast<EnumDecl>(D), Enum);
3040
3041  if (VarDecl *Var = dyn_cast<VarDecl>(Other))
3042    if (Var->isStaticDataMember())
3043      return isInstantiationOfStaticDataMember(cast<VarDecl>(D), Var);
3044
3045  if (ClassTemplateDecl *Temp = dyn_cast<ClassTemplateDecl>(Other))
3046    return isInstantiationOf(cast<ClassTemplateDecl>(D), Temp);
3047
3048  if (FunctionTemplateDecl *Temp = dyn_cast<FunctionTemplateDecl>(Other))
3049    return isInstantiationOf(cast<FunctionTemplateDecl>(D), Temp);
3050
3051  if (ClassTemplatePartialSpecializationDecl *PartialSpec
3052        = dyn_cast<ClassTemplatePartialSpecializationDecl>(Other))
3053    return isInstantiationOf(cast<ClassTemplatePartialSpecializationDecl>(D),
3054                             PartialSpec);
3055
3056  if (FieldDecl *Field = dyn_cast<FieldDecl>(Other)) {
3057    if (!Field->getDeclName()) {
3058      // This is an unnamed field.
3059      return Ctx.getInstantiatedFromUnnamedFieldDecl(Field) ==
3060        cast<FieldDecl>(D);
3061    }
3062  }
3063
3064  if (UsingDecl *Using = dyn_cast<UsingDecl>(Other))
3065    return isInstantiationOf(cast<UsingDecl>(D), Using, Ctx);
3066
3067  if (UsingShadowDecl *Shadow = dyn_cast<UsingShadowDecl>(Other))
3068    return isInstantiationOf(cast<UsingShadowDecl>(D), Shadow, Ctx);
3069
3070  return D->getDeclName() && isa<NamedDecl>(Other) &&
3071    D->getDeclName() == cast<NamedDecl>(Other)->getDeclName();
3072}
3073
3074template<typename ForwardIterator>
3075static NamedDecl *findInstantiationOf(ASTContext &Ctx,
3076                                      NamedDecl *D,
3077                                      ForwardIterator first,
3078                                      ForwardIterator last) {
3079  for (; first != last; ++first)
3080    if (isInstantiationOf(Ctx, D, *first))
3081      return cast<NamedDecl>(*first);
3082
3083  return 0;
3084}
3085
3086/// \brief Finds the instantiation of the given declaration context
3087/// within the current instantiation.
3088///
3089/// \returns NULL if there was an error
3090DeclContext *Sema::FindInstantiatedContext(SourceLocation Loc, DeclContext* DC,
3091                          const MultiLevelTemplateArgumentList &TemplateArgs) {
3092  if (NamedDecl *D = dyn_cast<NamedDecl>(DC)) {
3093    Decl* ID = FindInstantiatedDecl(Loc, D, TemplateArgs);
3094    return cast_or_null<DeclContext>(ID);
3095  } else return DC;
3096}
3097
3098/// \brief Find the instantiation of the given declaration within the
3099/// current instantiation.
3100///
3101/// This routine is intended to be used when \p D is a declaration
3102/// referenced from within a template, that needs to mapped into the
3103/// corresponding declaration within an instantiation. For example,
3104/// given:
3105///
3106/// \code
3107/// template<typename T>
3108/// struct X {
3109///   enum Kind {
3110///     KnownValue = sizeof(T)
3111///   };
3112///
3113///   bool getKind() const { return KnownValue; }
3114/// };
3115///
3116/// template struct X<int>;
3117/// \endcode
3118///
3119/// In the instantiation of X<int>::getKind(), we need to map the
3120/// EnumConstantDecl for KnownValue (which refers to
3121/// X<T>::<Kind>::KnownValue) to its instantiation
3122/// (X<int>::<Kind>::KnownValue). InstantiateCurrentDeclRef() performs
3123/// this mapping from within the instantiation of X<int>.
3124NamedDecl *Sema::FindInstantiatedDecl(SourceLocation Loc, NamedDecl *D,
3125                          const MultiLevelTemplateArgumentList &TemplateArgs) {
3126  DeclContext *ParentDC = D->getDeclContext();
3127  if (isa<ParmVarDecl>(D) || isa<NonTypeTemplateParmDecl>(D) ||
3128      isa<TemplateTypeParmDecl>(D) || isa<TemplateTemplateParmDecl>(D) ||
3129      (ParentDC->isFunctionOrMethod() && ParentDC->isDependentContext())) {
3130    // D is a local of some kind. Look into the map of local
3131    // declarations to their instantiations.
3132    typedef LocalInstantiationScope::DeclArgumentPack DeclArgumentPack;
3133    llvm::PointerUnion<Decl *, DeclArgumentPack *> *Found
3134      = CurrentInstantiationScope->findInstantiationOf(D);
3135
3136    if (Found) {
3137      if (Decl *FD = Found->dyn_cast<Decl *>())
3138        return cast<NamedDecl>(FD);
3139
3140      unsigned PackIdx = ArgumentPackSubstitutionIndex;
3141      return cast<NamedDecl>((*Found->get<DeclArgumentPack *>())[PackIdx]);
3142    }
3143
3144    // If we didn't find the decl, then we must have a label decl that hasn't
3145    // been found yet.  Lazily instantiate it and return it now.
3146    assert(isa<LabelDecl>(D));
3147
3148    Decl *Inst = SubstDecl(D, CurContext, TemplateArgs);
3149    assert(Inst && "Failed to instantiate label??");
3150
3151    CurrentInstantiationScope->InstantiatedLocal(D, Inst);
3152    return cast<LabelDecl>(Inst);
3153  }
3154
3155  if (CXXRecordDecl *Record = dyn_cast<CXXRecordDecl>(D)) {
3156    if (!Record->isDependentContext())
3157      return D;
3158
3159    // Determine whether this record is the "templated" declaration describing
3160    // a class template or class template partial specialization.
3161    ClassTemplateDecl *ClassTemplate = Record->getDescribedClassTemplate();
3162    if (ClassTemplate)
3163      ClassTemplate = ClassTemplate->getCanonicalDecl();
3164    else if (ClassTemplatePartialSpecializationDecl *PartialSpec
3165               = dyn_cast<ClassTemplatePartialSpecializationDecl>(Record))
3166      ClassTemplate = PartialSpec->getSpecializedTemplate()->getCanonicalDecl();
3167
3168    // Walk the current context to find either the record or an instantiation of
3169    // it.
3170    DeclContext *DC = CurContext;
3171    while (!DC->isFileContext()) {
3172      // If we're performing substitution while we're inside the template
3173      // definition, we'll find our own context. We're done.
3174      if (DC->Equals(Record))
3175        return Record;
3176
3177      if (CXXRecordDecl *InstRecord = dyn_cast<CXXRecordDecl>(DC)) {
3178        // Check whether we're in the process of instantiating a class template
3179        // specialization of the template we're mapping.
3180        if (ClassTemplateSpecializationDecl *InstSpec
3181                      = dyn_cast<ClassTemplateSpecializationDecl>(InstRecord)){
3182          ClassTemplateDecl *SpecTemplate = InstSpec->getSpecializedTemplate();
3183          if (ClassTemplate && isInstantiationOf(ClassTemplate, SpecTemplate))
3184            return InstRecord;
3185        }
3186
3187        // Check whether we're in the process of instantiating a member class.
3188        if (isInstantiationOf(Record, InstRecord))
3189          return InstRecord;
3190      }
3191
3192
3193      // Move to the outer template scope.
3194      if (FunctionDecl *FD = dyn_cast<FunctionDecl>(DC)) {
3195        if (FD->getFriendObjectKind() && FD->getDeclContext()->isFileContext()){
3196          DC = FD->getLexicalDeclContext();
3197          continue;
3198        }
3199      }
3200
3201      DC = DC->getParent();
3202    }
3203
3204    // Fall through to deal with other dependent record types (e.g.,
3205    // anonymous unions in class templates).
3206  }
3207
3208  if (!ParentDC->isDependentContext())
3209    return D;
3210
3211  ParentDC = FindInstantiatedContext(Loc, ParentDC, TemplateArgs);
3212  if (!ParentDC)
3213    return 0;
3214
3215  if (ParentDC != D->getDeclContext()) {
3216    // We performed some kind of instantiation in the parent context,
3217    // so now we need to look into the instantiated parent context to
3218    // find the instantiation of the declaration D.
3219
3220    // If our context used to be dependent, we may need to instantiate
3221    // it before performing lookup into that context.
3222    bool IsBeingInstantiated = false;
3223    if (CXXRecordDecl *Spec = dyn_cast<CXXRecordDecl>(ParentDC)) {
3224      if (!Spec->isDependentContext()) {
3225        QualType T = Context.getTypeDeclType(Spec);
3226        const RecordType *Tag = T->getAs<RecordType>();
3227        assert(Tag && "type of non-dependent record is not a RecordType");
3228        if (Tag->isBeingDefined())
3229          IsBeingInstantiated = true;
3230        if (!Tag->isBeingDefined() &&
3231            RequireCompleteType(Loc, T, diag::err_incomplete_type))
3232          return 0;
3233
3234        ParentDC = Tag->getDecl();
3235      }
3236    }
3237
3238    NamedDecl *Result = 0;
3239    if (D->getDeclName()) {
3240      DeclContext::lookup_result Found = ParentDC->lookup(D->getDeclName());
3241      Result = findInstantiationOf(Context, D, Found.first, Found.second);
3242    } else {
3243      // Since we don't have a name for the entity we're looking for,
3244      // our only option is to walk through all of the declarations to
3245      // find that name. This will occur in a few cases:
3246      //
3247      //   - anonymous struct/union within a template
3248      //   - unnamed class/struct/union/enum within a template
3249      //
3250      // FIXME: Find a better way to find these instantiations!
3251      Result = findInstantiationOf(Context, D,
3252                                   ParentDC->decls_begin(),
3253                                   ParentDC->decls_end());
3254    }
3255
3256    if (!Result) {
3257      if (isa<UsingShadowDecl>(D)) {
3258        // UsingShadowDecls can instantiate to nothing because of using hiding.
3259      } else if (Diags.hasErrorOccurred()) {
3260        // We've already complained about something, so most likely this
3261        // declaration failed to instantiate. There's no point in complaining
3262        // further, since this is normal in invalid code.
3263      } else if (IsBeingInstantiated) {
3264        // The class in which this member exists is currently being
3265        // instantiated, and we haven't gotten around to instantiating this
3266        // member yet. This can happen when the code uses forward declarations
3267        // of member classes, and introduces ordering dependencies via
3268        // template instantiation.
3269        Diag(Loc, diag::err_member_not_yet_instantiated)
3270          << D->getDeclName()
3271          << Context.getTypeDeclType(cast<CXXRecordDecl>(ParentDC));
3272        Diag(D->getLocation(), diag::note_non_instantiated_member_here);
3273      } else {
3274        // We should have found something, but didn't.
3275        llvm_unreachable("Unable to find instantiation of declaration!");
3276      }
3277    }
3278
3279    D = Result;
3280  }
3281
3282  return D;
3283}
3284
3285/// \brief Performs template instantiation for all implicit template
3286/// instantiations we have seen until this point.
3287void Sema::PerformPendingInstantiations(bool LocalOnly) {
3288  // Load pending instantiations from the external source.
3289  if (!LocalOnly && ExternalSource) {
3290    SmallVector<std::pair<ValueDecl *, SourceLocation>, 4> Pending;
3291    ExternalSource->ReadPendingInstantiations(Pending);
3292    PendingInstantiations.insert(PendingInstantiations.begin(),
3293                                 Pending.begin(), Pending.end());
3294  }
3295
3296  while (!PendingLocalImplicitInstantiations.empty() ||
3297         (!LocalOnly && !PendingInstantiations.empty())) {
3298    PendingImplicitInstantiation Inst;
3299
3300    if (PendingLocalImplicitInstantiations.empty()) {
3301      Inst = PendingInstantiations.front();
3302      PendingInstantiations.pop_front();
3303    } else {
3304      Inst = PendingLocalImplicitInstantiations.front();
3305      PendingLocalImplicitInstantiations.pop_front();
3306    }
3307
3308    // Instantiate function definitions
3309    if (FunctionDecl *Function = dyn_cast<FunctionDecl>(Inst.first)) {
3310      PrettyDeclStackTraceEntry CrashInfo(*this, Function, SourceLocation(),
3311                                          "instantiating function definition");
3312      bool DefinitionRequired = Function->getTemplateSpecializationKind() ==
3313                                TSK_ExplicitInstantiationDefinition;
3314      InstantiateFunctionDefinition(/*FIXME:*/Inst.second, Function, true,
3315                                    DefinitionRequired);
3316      continue;
3317    }
3318
3319    // Instantiate static data member definitions.
3320    VarDecl *Var = cast<VarDecl>(Inst.first);
3321    assert(Var->isStaticDataMember() && "Not a static data member?");
3322
3323    // Don't try to instantiate declarations if the most recent redeclaration
3324    // is invalid.
3325    if (Var->getMostRecentDeclaration()->isInvalidDecl())
3326      continue;
3327
3328    // Check if the most recent declaration has changed the specialization kind
3329    // and removed the need for implicit instantiation.
3330    switch (Var->getMostRecentDeclaration()->getTemplateSpecializationKind()) {
3331    case TSK_Undeclared:
3332      llvm_unreachable("Cannot instantitiate an undeclared specialization.");
3333    case TSK_ExplicitInstantiationDeclaration:
3334    case TSK_ExplicitSpecialization:
3335      continue;  // No longer need to instantiate this type.
3336    case TSK_ExplicitInstantiationDefinition:
3337      // We only need an instantiation if the pending instantiation *is* the
3338      // explicit instantiation.
3339      if (Var != Var->getMostRecentDeclaration()) continue;
3340    case TSK_ImplicitInstantiation:
3341      break;
3342    }
3343
3344    PrettyDeclStackTraceEntry CrashInfo(*this, Var, Var->getLocation(),
3345                                        "instantiating static data member "
3346                                        "definition");
3347
3348    bool DefinitionRequired = Var->getTemplateSpecializationKind() ==
3349                              TSK_ExplicitInstantiationDefinition;
3350    InstantiateStaticDataMemberDefinition(/*FIXME:*/Inst.second, Var, true,
3351                                          DefinitionRequired);
3352  }
3353}
3354
3355void Sema::PerformDependentDiagnostics(const DeclContext *Pattern,
3356                       const MultiLevelTemplateArgumentList &TemplateArgs) {
3357  for (DeclContext::ddiag_iterator I = Pattern->ddiag_begin(),
3358         E = Pattern->ddiag_end(); I != E; ++I) {
3359    DependentDiagnostic *DD = *I;
3360
3361    switch (DD->getKind()) {
3362    case DependentDiagnostic::Access:
3363      HandleDependentAccessCheck(*DD, TemplateArgs);
3364      break;
3365    }
3366  }
3367}
3368