SemaTemplateInstantiateDecl.cpp revision eb2d1f1c88836bd5382e5d7aa8f6b85148a88b27 
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  bool Redeclaration = false;
350  // FIXME: having to fake up a LookupResult is dumb.
351  LookupResult Previous(SemaRef, Var->getDeclName(), Var->getLocation(),
352                        Sema::LookupOrdinaryName, Sema::ForRedeclaration);
353  if (D->isStaticDataMember())
354    SemaRef.LookupQualifiedName(Previous, Owner, false);
355  SemaRef.CheckVariableDeclaration(Var, Previous, Redeclaration);
356
357  if (D->isOutOfLine()) {
358    if (!D->isStaticDataMember())
359      D->getLexicalDeclContext()->addDecl(Var);
360    Owner->makeDeclVisibleInContext(Var);
361  } else {
362    Owner->addDecl(Var);
363    if (Owner->isFunctionOrMethod())
364      SemaRef.CurrentInstantiationScope->InstantiatedLocal(D, Var);
365  }
366  SemaRef.InstantiateAttrs(TemplateArgs, D, Var);
367
368  // Link instantiations of static data members back to the template from
369  // which they were instantiated.
370  if (Var->isStaticDataMember())
371    SemaRef.Context.setInstantiatedFromStaticDataMember(Var, D,
372                                                     TSK_ImplicitInstantiation);
373
374  if (Var->getAnyInitializer()) {
375    // We already have an initializer in the class.
376  } else if (D->getInit()) {
377    if (Var->isStaticDataMember() && !D->isOutOfLine())
378      SemaRef.PushExpressionEvaluationContext(Sema::Unevaluated);
379    else
380      SemaRef.PushExpressionEvaluationContext(Sema::PotentiallyEvaluated);
381
382    // Instantiate the initializer.
383    SourceLocation LParenLoc, RParenLoc;
384    ASTOwningVector<Expr*> InitArgs(SemaRef);
385    if (!SemaRef.InstantiateInitializer(D->getInit(), TemplateArgs, LParenLoc,
386                                        InitArgs, RParenLoc)) {
387      bool TypeMayContainAuto = true;
388      // Attach the initializer to the declaration, if we have one.
389      if (InitArgs.size() == 0)
390        SemaRef.ActOnUninitializedDecl(Var, TypeMayContainAuto);
391      else if (D->hasCXXDirectInitializer()) {
392        // Add the direct initializer to the declaration.
393        SemaRef.AddCXXDirectInitializerToDecl(Var,
394                                              LParenLoc,
395                                              move_arg(InitArgs),
396                                              RParenLoc,
397                                              TypeMayContainAuto);
398      } else {
399        assert(InitArgs.size() == 1);
400        Expr *Init = InitArgs.take()[0];
401        SemaRef.AddInitializerToDecl(Var, Init, false, TypeMayContainAuto);
402      }
403    } else {
404      // FIXME: Not too happy about invalidating the declaration
405      // because of a bogus initializer.
406      Var->setInvalidDecl();
407    }
408
409    SemaRef.PopExpressionEvaluationContext();
410  } else if ((!Var->isStaticDataMember() || Var->isOutOfLine()) &&
411             !Var->isCXXForRangeDecl())
412    SemaRef.ActOnUninitializedDecl(Var, false);
413
414  // Diagnose unused local variables with dependent types, where the diagnostic
415  // will have been deferred.
416  if (!Var->isInvalidDecl() && Owner->isFunctionOrMethod() && !Var->isUsed() &&
417      D->getType()->isDependentType())
418    SemaRef.DiagnoseUnusedDecl(Var);
419
420  return Var;
421}
422
423Decl *TemplateDeclInstantiator::VisitAccessSpecDecl(AccessSpecDecl *D) {
424  AccessSpecDecl* AD
425    = AccessSpecDecl::Create(SemaRef.Context, D->getAccess(), Owner,
426                             D->getAccessSpecifierLoc(), D->getColonLoc());
427  Owner->addHiddenDecl(AD);
428  return AD;
429}
430
431Decl *TemplateDeclInstantiator::VisitFieldDecl(FieldDecl *D) {
432  bool Invalid = false;
433  TypeSourceInfo *DI = D->getTypeSourceInfo();
434  if (DI->getType()->isInstantiationDependentType() ||
435      DI->getType()->isVariablyModifiedType())  {
436    DI = SemaRef.SubstType(DI, TemplateArgs,
437                           D->getLocation(), D->getDeclName());
438    if (!DI) {
439      DI = D->getTypeSourceInfo();
440      Invalid = true;
441    } else if (DI->getType()->isFunctionType()) {
442      // C++ [temp.arg.type]p3:
443      //   If a declaration acquires a function type through a type
444      //   dependent on a template-parameter and this causes a
445      //   declaration that does not use the syntactic form of a
446      //   function declarator to have function type, the program is
447      //   ill-formed.
448      SemaRef.Diag(D->getLocation(), diag::err_field_instantiates_to_function)
449        << DI->getType();
450      Invalid = true;
451    }
452  } else {
453    SemaRef.MarkDeclarationsReferencedInType(D->getLocation(), DI->getType());
454  }
455
456  Expr *BitWidth = D->getBitWidth();
457  if (Invalid)
458    BitWidth = 0;
459  else if (BitWidth) {
460    // The bit-width expression is not potentially evaluated.
461    EnterExpressionEvaluationContext Unevaluated(SemaRef, Sema::Unevaluated);
462
463    ExprResult InstantiatedBitWidth
464      = SemaRef.SubstExpr(BitWidth, TemplateArgs);
465    if (InstantiatedBitWidth.isInvalid()) {
466      Invalid = true;
467      BitWidth = 0;
468    } else
469      BitWidth = InstantiatedBitWidth.takeAs<Expr>();
470  }
471
472  FieldDecl *Field = SemaRef.CheckFieldDecl(D->getDeclName(),
473                                            DI->getType(), DI,
474                                            cast<RecordDecl>(Owner),
475                                            D->getLocation(),
476                                            D->isMutable(),
477                                            BitWidth,
478                                            D->hasInClassInitializer(),
479                                            D->getTypeSpecStartLoc(),
480                                            D->getAccess(),
481                                            0);
482  if (!Field) {
483    cast<Decl>(Owner)->setInvalidDecl();
484    return 0;
485  }
486
487  SemaRef.InstantiateAttrs(TemplateArgs, D, Field);
488
489  if (Invalid)
490    Field->setInvalidDecl();
491
492  if (!Field->getDeclName()) {
493    // Keep track of where this decl came from.
494    SemaRef.Context.setInstantiatedFromUnnamedFieldDecl(Field, D);
495  }
496  if (CXXRecordDecl *Parent= dyn_cast<CXXRecordDecl>(Field->getDeclContext())) {
497    if (Parent->isAnonymousStructOrUnion() &&
498        Parent->getRedeclContext()->isFunctionOrMethod())
499      SemaRef.CurrentInstantiationScope->InstantiatedLocal(D, Field);
500  }
501
502  Field->setImplicit(D->isImplicit());
503  Field->setAccess(D->getAccess());
504  Owner->addDecl(Field);
505
506  return Field;
507}
508
509Decl *TemplateDeclInstantiator::VisitIndirectFieldDecl(IndirectFieldDecl *D) {
510  NamedDecl **NamedChain =
511    new (SemaRef.Context)NamedDecl*[D->getChainingSize()];
512
513  int i = 0;
514  for (IndirectFieldDecl::chain_iterator PI =
515       D->chain_begin(), PE = D->chain_end();
516       PI != PE; ++PI) {
517    NamedDecl *Next = SemaRef.FindInstantiatedDecl(D->getLocation(), *PI,
518                                              TemplateArgs);
519    if (!Next)
520      return 0;
521
522    NamedChain[i++] = Next;
523  }
524
525  QualType T = cast<FieldDecl>(NamedChain[i-1])->getType();
526  IndirectFieldDecl* IndirectField
527    = IndirectFieldDecl::Create(SemaRef.Context, Owner, D->getLocation(),
528                                D->getIdentifier(), T,
529                                NamedChain, D->getChainingSize());
530
531
532  IndirectField->setImplicit(D->isImplicit());
533  IndirectField->setAccess(D->getAccess());
534  Owner->addDecl(IndirectField);
535  return IndirectField;
536}
537
538Decl *TemplateDeclInstantiator::VisitFriendDecl(FriendDecl *D) {
539  // Handle friend type expressions by simply substituting template
540  // parameters into the pattern type and checking the result.
541  if (TypeSourceInfo *Ty = D->getFriendType()) {
542    TypeSourceInfo *InstTy;
543    // If this is an unsupported friend, don't bother substituting template
544    // arguments into it. The actual type referred to won't be used by any
545    // parts of Clang, and may not be valid for instantiating. Just use the
546    // same info for the instantiated friend.
547    if (D->isUnsupportedFriend()) {
548      InstTy = Ty;
549    } else {
550      InstTy = SemaRef.SubstType(Ty, TemplateArgs,
551                                 D->getLocation(), DeclarationName());
552    }
553    if (!InstTy)
554      return 0;
555
556    FriendDecl *FD = SemaRef.CheckFriendTypeDecl(D->getFriendLoc(), InstTy);
557    if (!FD)
558      return 0;
559
560    FD->setAccess(AS_public);
561    FD->setUnsupportedFriend(D->isUnsupportedFriend());
562    Owner->addDecl(FD);
563    return FD;
564  }
565
566  NamedDecl *ND = D->getFriendDecl();
567  assert(ND && "friend decl must be a decl or a type!");
568
569  // All of the Visit implementations for the various potential friend
570  // declarations have to be carefully written to work for friend
571  // objects, with the most important detail being that the target
572  // decl should almost certainly not be placed in Owner.
573  Decl *NewND = Visit(ND);
574  if (!NewND) return 0;
575
576  FriendDecl *FD =
577    FriendDecl::Create(SemaRef.Context, Owner, D->getLocation(),
578                       cast<NamedDecl>(NewND), D->getFriendLoc());
579  FD->setAccess(AS_public);
580  FD->setUnsupportedFriend(D->isUnsupportedFriend());
581  Owner->addDecl(FD);
582  return FD;
583}
584
585Decl *TemplateDeclInstantiator::VisitStaticAssertDecl(StaticAssertDecl *D) {
586  Expr *AssertExpr = D->getAssertExpr();
587
588  // The expression in a static assertion is not potentially evaluated.
589  EnterExpressionEvaluationContext Unevaluated(SemaRef, Sema::Unevaluated);
590
591  ExprResult InstantiatedAssertExpr
592    = SemaRef.SubstExpr(AssertExpr, TemplateArgs);
593  if (InstantiatedAssertExpr.isInvalid())
594    return 0;
595
596  ExprResult Message(D->getMessage());
597  D->getMessage();
598  return SemaRef.ActOnStaticAssertDeclaration(D->getLocation(),
599                                              InstantiatedAssertExpr.get(),
600                                              Message.get(),
601                                              D->getRParenLoc());
602}
603
604Decl *TemplateDeclInstantiator::VisitEnumDecl(EnumDecl *D) {
605  EnumDecl *Enum = EnumDecl::Create(SemaRef.Context, Owner, D->getLocStart(),
606                                    D->getLocation(), D->getIdentifier(),
607                                    /*PrevDecl=*/0, D->isScoped(),
608                                    D->isScopedUsingClassTag(), D->isFixed());
609  if (D->isFixed()) {
610    if (TypeSourceInfo* TI = D->getIntegerTypeSourceInfo()) {
611      // If we have type source information for the underlying type, it means it
612      // has been explicitly set by the user. Perform substitution on it before
613      // moving on.
614      SourceLocation UnderlyingLoc = TI->getTypeLoc().getBeginLoc();
615      Enum->setIntegerTypeSourceInfo(SemaRef.SubstType(TI,
616                                                       TemplateArgs,
617                                                       UnderlyingLoc,
618                                                       DeclarationName()));
619
620      if (!Enum->getIntegerTypeSourceInfo())
621        Enum->setIntegerType(SemaRef.Context.IntTy);
622    }
623    else {
624      assert(!D->getIntegerType()->isDependentType()
625             && "Dependent type without type source info");
626      Enum->setIntegerType(D->getIntegerType());
627    }
628  }
629
630  SemaRef.InstantiateAttrs(TemplateArgs, D, Enum);
631
632  Enum->setInstantiationOfMemberEnum(D);
633  Enum->setAccess(D->getAccess());
634  if (SubstQualifier(D, Enum)) return 0;
635  Owner->addDecl(Enum);
636  Enum->startDefinition();
637
638  if (D->getDeclContext()->isFunctionOrMethod())
639    SemaRef.CurrentInstantiationScope->InstantiatedLocal(D, Enum);
640
641  SmallVector<Decl*, 4> Enumerators;
642
643  EnumConstantDecl *LastEnumConst = 0;
644  for (EnumDecl::enumerator_iterator EC = D->enumerator_begin(),
645         ECEnd = D->enumerator_end();
646       EC != ECEnd; ++EC) {
647    // The specified value for the enumerator.
648    ExprResult Value = SemaRef.Owned((Expr *)0);
649    if (Expr *UninstValue = EC->getInitExpr()) {
650      // The enumerator's value expression is not potentially evaluated.
651      EnterExpressionEvaluationContext Unevaluated(SemaRef,
652                                                   Sema::Unevaluated);
653
654      Value = SemaRef.SubstExpr(UninstValue, TemplateArgs);
655    }
656
657    // Drop the initial value and continue.
658    bool isInvalid = false;
659    if (Value.isInvalid()) {
660      Value = SemaRef.Owned((Expr *)0);
661      isInvalid = true;
662    }
663
664    EnumConstantDecl *EnumConst
665      = SemaRef.CheckEnumConstant(Enum, LastEnumConst,
666                                  EC->getLocation(), EC->getIdentifier(),
667                                  Value.get());
668
669    if (isInvalid) {
670      if (EnumConst)
671        EnumConst->setInvalidDecl();
672      Enum->setInvalidDecl();
673    }
674
675    if (EnumConst) {
676      SemaRef.InstantiateAttrs(TemplateArgs, *EC, EnumConst);
677
678      EnumConst->setAccess(Enum->getAccess());
679      Enum->addDecl(EnumConst);
680      Enumerators.push_back(EnumConst);
681      LastEnumConst = EnumConst;
682
683      if (D->getDeclContext()->isFunctionOrMethod()) {
684        // If the enumeration is within a function or method, record the enum
685        // constant as a local.
686        SemaRef.CurrentInstantiationScope->InstantiatedLocal(*EC, EnumConst);
687      }
688    }
689  }
690
691  // FIXME: Fixup LBraceLoc and RBraceLoc
692  // FIXME: Empty Scope and AttributeList (required to handle attribute packed).
693  SemaRef.ActOnEnumBody(Enum->getLocation(), SourceLocation(), SourceLocation(),
694                        Enum,
695                        Enumerators.data(), Enumerators.size(),
696                        0, 0);
697
698  return Enum;
699}
700
701Decl *TemplateDeclInstantiator::VisitEnumConstantDecl(EnumConstantDecl *D) {
702  llvm_unreachable("EnumConstantDecls can only occur within EnumDecls.");
703}
704
705Decl *TemplateDeclInstantiator::VisitClassTemplateDecl(ClassTemplateDecl *D) {
706  bool isFriend = (D->getFriendObjectKind() != Decl::FOK_None);
707
708  // Create a local instantiation scope for this class template, which
709  // will contain the instantiations of the template parameters.
710  LocalInstantiationScope Scope(SemaRef);
711  TemplateParameterList *TempParams = D->getTemplateParameters();
712  TemplateParameterList *InstParams = SubstTemplateParams(TempParams);
713  if (!InstParams)
714    return NULL;
715
716  CXXRecordDecl *Pattern = D->getTemplatedDecl();
717
718  // Instantiate the qualifier.  We have to do this first in case
719  // we're a friend declaration, because if we are then we need to put
720  // the new declaration in the appropriate context.
721  NestedNameSpecifierLoc QualifierLoc = Pattern->getQualifierLoc();
722  if (QualifierLoc) {
723    QualifierLoc = SemaRef.SubstNestedNameSpecifierLoc(QualifierLoc,
724                                                       TemplateArgs);
725    if (!QualifierLoc)
726      return 0;
727  }
728
729  CXXRecordDecl *PrevDecl = 0;
730  ClassTemplateDecl *PrevClassTemplate = 0;
731
732  if (!isFriend && Pattern->getPreviousDeclaration()) {
733    DeclContext::lookup_result Found = Owner->lookup(Pattern->getDeclName());
734    if (Found.first != Found.second) {
735      PrevClassTemplate = dyn_cast<ClassTemplateDecl>(*Found.first);
736      if (PrevClassTemplate)
737        PrevDecl = PrevClassTemplate->getTemplatedDecl();
738    }
739  }
740
741  // If this isn't a friend, then it's a member template, in which
742  // case we just want to build the instantiation in the
743  // specialization.  If it is a friend, we want to build it in
744  // the appropriate context.
745  DeclContext *DC = Owner;
746  if (isFriend) {
747    if (QualifierLoc) {
748      CXXScopeSpec SS;
749      SS.Adopt(QualifierLoc);
750      DC = SemaRef.computeDeclContext(SS);
751      if (!DC) return 0;
752    } else {
753      DC = SemaRef.FindInstantiatedContext(Pattern->getLocation(),
754                                           Pattern->getDeclContext(),
755                                           TemplateArgs);
756    }
757
758    // Look for a previous declaration of the template in the owning
759    // context.
760    LookupResult R(SemaRef, Pattern->getDeclName(), Pattern->getLocation(),
761                   Sema::LookupOrdinaryName, Sema::ForRedeclaration);
762    SemaRef.LookupQualifiedName(R, DC);
763
764    if (R.isSingleResult()) {
765      PrevClassTemplate = R.getAsSingle<ClassTemplateDecl>();
766      if (PrevClassTemplate)
767        PrevDecl = PrevClassTemplate->getTemplatedDecl();
768    }
769
770    if (!PrevClassTemplate && QualifierLoc) {
771      SemaRef.Diag(Pattern->getLocation(), diag::err_not_tag_in_scope)
772        << D->getTemplatedDecl()->getTagKind() << Pattern->getDeclName() << DC
773        << QualifierLoc.getSourceRange();
774      return 0;
775    }
776
777    bool AdoptedPreviousTemplateParams = false;
778    if (PrevClassTemplate) {
779      bool Complain = true;
780
781      // HACK: libstdc++ 4.2.1 contains an ill-formed friend class
782      // template for struct std::tr1::__detail::_Map_base, where the
783      // template parameters of the friend declaration don't match the
784      // template parameters of the original declaration. In this one
785      // case, we don't complain about the ill-formed friend
786      // declaration.
787      if (isFriend && Pattern->getIdentifier() &&
788          Pattern->getIdentifier()->isStr("_Map_base") &&
789          DC->isNamespace() &&
790          cast<NamespaceDecl>(DC)->getIdentifier() &&
791          cast<NamespaceDecl>(DC)->getIdentifier()->isStr("__detail")) {
792        DeclContext *DCParent = DC->getParent();
793        if (DCParent->isNamespace() &&
794            cast<NamespaceDecl>(DCParent)->getIdentifier() &&
795            cast<NamespaceDecl>(DCParent)->getIdentifier()->isStr("tr1")) {
796          DeclContext *DCParent2 = DCParent->getParent();
797          if (DCParent2->isNamespace() &&
798              cast<NamespaceDecl>(DCParent2)->getIdentifier() &&
799              cast<NamespaceDecl>(DCParent2)->getIdentifier()->isStr("std") &&
800              DCParent2->getParent()->isTranslationUnit())
801            Complain = false;
802        }
803      }
804
805      TemplateParameterList *PrevParams
806        = PrevClassTemplate->getTemplateParameters();
807
808      // Make sure the parameter lists match.
809      if (!SemaRef.TemplateParameterListsAreEqual(InstParams, PrevParams,
810                                                  Complain,
811                                                  Sema::TPL_TemplateMatch)) {
812        if (Complain)
813          return 0;
814
815        AdoptedPreviousTemplateParams = true;
816        InstParams = PrevParams;
817      }
818
819      // Do some additional validation, then merge default arguments
820      // from the existing declarations.
821      if (!AdoptedPreviousTemplateParams &&
822          SemaRef.CheckTemplateParameterList(InstParams, PrevParams,
823                                             Sema::TPC_ClassTemplate))
824        return 0;
825    }
826  }
827
828  CXXRecordDecl *RecordInst
829    = CXXRecordDecl::Create(SemaRef.Context, Pattern->getTagKind(), DC,
830                            Pattern->getLocStart(), Pattern->getLocation(),
831                            Pattern->getIdentifier(), PrevDecl,
832                            /*DelayTypeCreation=*/true);
833
834  if (QualifierLoc)
835    RecordInst->setQualifierInfo(QualifierLoc);
836
837  ClassTemplateDecl *Inst
838    = ClassTemplateDecl::Create(SemaRef.Context, DC, D->getLocation(),
839                                D->getIdentifier(), InstParams, RecordInst,
840                                PrevClassTemplate);
841  RecordInst->setDescribedClassTemplate(Inst);
842
843  if (isFriend) {
844    if (PrevClassTemplate)
845      Inst->setAccess(PrevClassTemplate->getAccess());
846    else
847      Inst->setAccess(D->getAccess());
848
849    Inst->setObjectOfFriendDecl(PrevClassTemplate != 0);
850    // TODO: do we want to track the instantiation progeny of this
851    // friend target decl?
852  } else {
853    Inst->setAccess(D->getAccess());
854    if (!PrevClassTemplate)
855      Inst->setInstantiatedFromMemberTemplate(D);
856  }
857
858  // Trigger creation of the type for the instantiation.
859  SemaRef.Context.getInjectedClassNameType(RecordInst,
860                                    Inst->getInjectedClassNameSpecialization());
861
862  // Finish handling of friends.
863  if (isFriend) {
864    DC->makeDeclVisibleInContext(Inst, /*Recoverable*/ false);
865    return Inst;
866  }
867
868  Owner->addDecl(Inst);
869
870  if (!PrevClassTemplate) {
871    // Queue up any out-of-line partial specializations of this member
872    // class template; the client will force their instantiation once
873    // the enclosing class has been instantiated.
874    SmallVector<ClassTemplatePartialSpecializationDecl *, 4> PartialSpecs;
875    D->getPartialSpecializations(PartialSpecs);
876    for (unsigned I = 0, N = PartialSpecs.size(); I != N; ++I)
877      if (PartialSpecs[I]->isOutOfLine())
878        OutOfLinePartialSpecs.push_back(std::make_pair(Inst, PartialSpecs[I]));
879  }
880
881  return Inst;
882}
883
884Decl *
885TemplateDeclInstantiator::VisitClassTemplatePartialSpecializationDecl(
886                                   ClassTemplatePartialSpecializationDecl *D) {
887  ClassTemplateDecl *ClassTemplate = D->getSpecializedTemplate();
888
889  // Lookup the already-instantiated declaration in the instantiation
890  // of the class template and return that.
891  DeclContext::lookup_result Found
892    = Owner->lookup(ClassTemplate->getDeclName());
893  if (Found.first == Found.second)
894    return 0;
895
896  ClassTemplateDecl *InstClassTemplate
897    = dyn_cast<ClassTemplateDecl>(*Found.first);
898  if (!InstClassTemplate)
899    return 0;
900
901  if (ClassTemplatePartialSpecializationDecl *Result
902        = InstClassTemplate->findPartialSpecInstantiatedFromMember(D))
903    return Result;
904
905  return InstantiateClassTemplatePartialSpecialization(InstClassTemplate, D);
906}
907
908Decl *
909TemplateDeclInstantiator::VisitFunctionTemplateDecl(FunctionTemplateDecl *D) {
910  // Create a local instantiation scope for this function template, which
911  // will contain the instantiations of the template parameters and then get
912  // merged with the local instantiation scope for the function template
913  // itself.
914  LocalInstantiationScope Scope(SemaRef);
915
916  TemplateParameterList *TempParams = D->getTemplateParameters();
917  TemplateParameterList *InstParams = SubstTemplateParams(TempParams);
918  if (!InstParams)
919    return NULL;
920
921  FunctionDecl *Instantiated = 0;
922  if (CXXMethodDecl *DMethod = dyn_cast<CXXMethodDecl>(D->getTemplatedDecl()))
923    Instantiated = cast_or_null<FunctionDecl>(VisitCXXMethodDecl(DMethod,
924                                                                 InstParams));
925  else
926    Instantiated = cast_or_null<FunctionDecl>(VisitFunctionDecl(
927                                                          D->getTemplatedDecl(),
928                                                                InstParams));
929
930  if (!Instantiated)
931    return 0;
932
933  Instantiated->setAccess(D->getAccess());
934
935  // Link the instantiated function template declaration to the function
936  // template from which it was instantiated.
937  FunctionTemplateDecl *InstTemplate
938    = Instantiated->getDescribedFunctionTemplate();
939  InstTemplate->setAccess(D->getAccess());
940  assert(InstTemplate &&
941         "VisitFunctionDecl/CXXMethodDecl didn't create a template!");
942
943  bool isFriend = (InstTemplate->getFriendObjectKind() != Decl::FOK_None);
944
945  // Link the instantiation back to the pattern *unless* this is a
946  // non-definition friend declaration.
947  if (!InstTemplate->getInstantiatedFromMemberTemplate() &&
948      !(isFriend && !D->getTemplatedDecl()->isThisDeclarationADefinition()))
949    InstTemplate->setInstantiatedFromMemberTemplate(D);
950
951  // Make declarations visible in the appropriate context.
952  if (!isFriend)
953    Owner->addDecl(InstTemplate);
954
955  return InstTemplate;
956}
957
958Decl *TemplateDeclInstantiator::VisitCXXRecordDecl(CXXRecordDecl *D) {
959  CXXRecordDecl *PrevDecl = 0;
960  if (D->isInjectedClassName())
961    PrevDecl = cast<CXXRecordDecl>(Owner);
962  else if (D->getPreviousDeclaration()) {
963    NamedDecl *Prev = SemaRef.FindInstantiatedDecl(D->getLocation(),
964                                                   D->getPreviousDeclaration(),
965                                                   TemplateArgs);
966    if (!Prev) return 0;
967    PrevDecl = cast<CXXRecordDecl>(Prev);
968  }
969
970  CXXRecordDecl *Record
971    = CXXRecordDecl::Create(SemaRef.Context, D->getTagKind(), Owner,
972                            D->getLocStart(), D->getLocation(),
973                            D->getIdentifier(), PrevDecl);
974
975  // Substitute the nested name specifier, if any.
976  if (SubstQualifier(D, Record))
977    return 0;
978
979  Record->setImplicit(D->isImplicit());
980  // FIXME: Check against AS_none is an ugly hack to work around the issue that
981  // the tag decls introduced by friend class declarations don't have an access
982  // specifier. Remove once this area of the code gets sorted out.
983  if (D->getAccess() != AS_none)
984    Record->setAccess(D->getAccess());
985  if (!D->isInjectedClassName())
986    Record->setInstantiationOfMemberClass(D, TSK_ImplicitInstantiation);
987
988  // If the original function was part of a friend declaration,
989  // inherit its namespace state.
990  if (Decl::FriendObjectKind FOK = D->getFriendObjectKind())
991    Record->setObjectOfFriendDecl(FOK == Decl::FOK_Declared);
992
993  // Make sure that anonymous structs and unions are recorded.
994  if (D->isAnonymousStructOrUnion()) {
995    Record->setAnonymousStructOrUnion(true);
996    if (Record->getDeclContext()->getRedeclContext()->isFunctionOrMethod())
997      SemaRef.CurrentInstantiationScope->InstantiatedLocal(D, Record);
998  }
999
1000  Owner->addDecl(Record);
1001  return Record;
1002}
1003
1004/// Normal class members are of more specific types and therefore
1005/// don't make it here.  This function serves two purposes:
1006///   1) instantiating function templates
1007///   2) substituting friend declarations
1008/// FIXME: preserve function definitions in case #2
1009Decl *TemplateDeclInstantiator::VisitFunctionDecl(FunctionDecl *D,
1010                                       TemplateParameterList *TemplateParams) {
1011  // Check whether there is already a function template specialization for
1012  // this declaration.
1013  FunctionTemplateDecl *FunctionTemplate = D->getDescribedFunctionTemplate();
1014  void *InsertPos = 0;
1015  if (FunctionTemplate && !TemplateParams) {
1016    std::pair<const TemplateArgument *, unsigned> Innermost
1017      = TemplateArgs.getInnermost();
1018
1019    FunctionDecl *SpecFunc
1020      = FunctionTemplate->findSpecialization(Innermost.first, Innermost.second,
1021                                             InsertPos);
1022
1023    // If we already have a function template specialization, return it.
1024    if (SpecFunc)
1025      return SpecFunc;
1026  }
1027
1028  bool isFriend;
1029  if (FunctionTemplate)
1030    isFriend = (FunctionTemplate->getFriendObjectKind() != Decl::FOK_None);
1031  else
1032    isFriend = (D->getFriendObjectKind() != Decl::FOK_None);
1033
1034  bool MergeWithParentScope = (TemplateParams != 0) ||
1035    Owner->isFunctionOrMethod() ||
1036    !(isa<Decl>(Owner) &&
1037      cast<Decl>(Owner)->isDefinedOutsideFunctionOrMethod());
1038  LocalInstantiationScope Scope(SemaRef, MergeWithParentScope);
1039
1040  SmallVector<ParmVarDecl *, 4> Params;
1041  TypeSourceInfo *TInfo = D->getTypeSourceInfo();
1042  TInfo = SubstFunctionType(D, Params);
1043  if (!TInfo)
1044    return 0;
1045  QualType T = TInfo->getType();
1046
1047  NestedNameSpecifierLoc QualifierLoc = D->getQualifierLoc();
1048  if (QualifierLoc) {
1049    QualifierLoc = SemaRef.SubstNestedNameSpecifierLoc(QualifierLoc,
1050                                                       TemplateArgs);
1051    if (!QualifierLoc)
1052      return 0;
1053  }
1054
1055  // If we're instantiating a local function declaration, put the result
1056  // in the owner;  otherwise we need to find the instantiated context.
1057  DeclContext *DC;
1058  if (D->getDeclContext()->isFunctionOrMethod())
1059    DC = Owner;
1060  else if (isFriend && QualifierLoc) {
1061    CXXScopeSpec SS;
1062    SS.Adopt(QualifierLoc);
1063    DC = SemaRef.computeDeclContext(SS);
1064    if (!DC) return 0;
1065  } else {
1066    DC = SemaRef.FindInstantiatedContext(D->getLocation(), D->getDeclContext(),
1067                                         TemplateArgs);
1068  }
1069
1070  bool isConstexpr = D->isConstexpr();
1071  // FIXME: check whether the instantiation produces a constexpr function.
1072
1073  FunctionDecl *Function =
1074      FunctionDecl::Create(SemaRef.Context, DC, D->getInnerLocStart(),
1075                           D->getLocation(), D->getDeclName(), T, TInfo,
1076                           D->getStorageClass(), D->getStorageClassAsWritten(),
1077                           D->isInlineSpecified(), D->hasWrittenPrototype(),
1078                           isConstexpr);
1079
1080  if (QualifierLoc)
1081    Function->setQualifierInfo(QualifierLoc);
1082
1083  DeclContext *LexicalDC = Owner;
1084  if (!isFriend && D->isOutOfLine()) {
1085    assert(D->getDeclContext()->isFileContext());
1086    LexicalDC = D->getDeclContext();
1087  }
1088
1089  Function->setLexicalDeclContext(LexicalDC);
1090
1091  // Attach the parameters
1092  if (isa<FunctionProtoType>(Function->getType().IgnoreParens())) {
1093    // Adopt the already-instantiated parameters into our own context.
1094    for (unsigned P = 0; P < Params.size(); ++P)
1095      if (Params[P])
1096        Params[P]->setOwningFunction(Function);
1097  } else {
1098    // Since we were instantiated via a typedef of a function type, create
1099    // new parameters.
1100    const FunctionProtoType *Proto
1101      = Function->getType()->getAs<FunctionProtoType>();
1102    assert(Proto && "No function prototype in template instantiation?");
1103    for (FunctionProtoType::arg_type_iterator AI = Proto->arg_type_begin(),
1104         AE = Proto->arg_type_end(); AI != AE; ++AI) {
1105      ParmVarDecl *Param
1106        = SemaRef.BuildParmVarDeclForTypedef(Function, Function->getLocation(),
1107                                             *AI);
1108      Param->setScopeInfo(0, Params.size());
1109      Params.push_back(Param);
1110    }
1111  }
1112  Function->setParams(Params);
1113
1114  SourceLocation InstantiateAtPOI;
1115  if (TemplateParams) {
1116    // Our resulting instantiation is actually a function template, since we
1117    // are substituting only the outer template parameters. For example, given
1118    //
1119    //   template<typename T>
1120    //   struct X {
1121    //     template<typename U> friend void f(T, U);
1122    //   };
1123    //
1124    //   X<int> x;
1125    //
1126    // We are instantiating the friend function template "f" within X<int>,
1127    // which means substituting int for T, but leaving "f" as a friend function
1128    // template.
1129    // Build the function template itself.
1130    FunctionTemplate = FunctionTemplateDecl::Create(SemaRef.Context, DC,
1131                                                    Function->getLocation(),
1132                                                    Function->getDeclName(),
1133                                                    TemplateParams, Function);
1134    Function->setDescribedFunctionTemplate(FunctionTemplate);
1135
1136    FunctionTemplate->setLexicalDeclContext(LexicalDC);
1137
1138    if (isFriend && D->isThisDeclarationADefinition()) {
1139      // TODO: should we remember this connection regardless of whether
1140      // the friend declaration provided a body?
1141      FunctionTemplate->setInstantiatedFromMemberTemplate(
1142                                           D->getDescribedFunctionTemplate());
1143    }
1144  } else if (FunctionTemplate) {
1145    // Record this function template specialization.
1146    std::pair<const TemplateArgument *, unsigned> Innermost
1147      = TemplateArgs.getInnermost();
1148    Function->setFunctionTemplateSpecialization(FunctionTemplate,
1149                            TemplateArgumentList::CreateCopy(SemaRef.Context,
1150                                                             Innermost.first,
1151                                                             Innermost.second),
1152                                                InsertPos);
1153  } else if (isFriend) {
1154    // Note, we need this connection even if the friend doesn't have a body.
1155    // Its body may exist but not have been attached yet due to deferred
1156    // parsing.
1157    // FIXME: It might be cleaner to set this when attaching the body to the
1158    // friend function declaration, however that would require finding all the
1159    // instantiations and modifying them.
1160    Function->setInstantiationOfMemberFunction(D, TSK_ImplicitInstantiation);
1161  }
1162
1163  if (InitFunctionInstantiation(Function, D))
1164    Function->setInvalidDecl();
1165
1166  bool Redeclaration = false;
1167  bool isExplicitSpecialization = false;
1168
1169  LookupResult Previous(SemaRef, Function->getDeclName(), SourceLocation(),
1170                        Sema::LookupOrdinaryName, Sema::ForRedeclaration);
1171
1172  if (DependentFunctionTemplateSpecializationInfo *Info
1173        = D->getDependentSpecializationInfo()) {
1174    assert(isFriend && "non-friend has dependent specialization info?");
1175
1176    // This needs to be set now for future sanity.
1177    Function->setObjectOfFriendDecl(/*HasPrevious*/ true);
1178
1179    // Instantiate the explicit template arguments.
1180    TemplateArgumentListInfo ExplicitArgs(Info->getLAngleLoc(),
1181                                          Info->getRAngleLoc());
1182    if (SemaRef.Subst(Info->getTemplateArgs(), Info->getNumTemplateArgs(),
1183                      ExplicitArgs, TemplateArgs))
1184      return 0;
1185
1186    // Map the candidate templates to their instantiations.
1187    for (unsigned I = 0, E = Info->getNumTemplates(); I != E; ++I) {
1188      Decl *Temp = SemaRef.FindInstantiatedDecl(D->getLocation(),
1189                                                Info->getTemplate(I),
1190                                                TemplateArgs);
1191      if (!Temp) return 0;
1192
1193      Previous.addDecl(cast<FunctionTemplateDecl>(Temp));
1194    }
1195
1196    if (SemaRef.CheckFunctionTemplateSpecialization(Function,
1197                                                    &ExplicitArgs,
1198                                                    Previous))
1199      Function->setInvalidDecl();
1200
1201    isExplicitSpecialization = true;
1202
1203  } else if (TemplateParams || !FunctionTemplate) {
1204    // Look only into the namespace where the friend would be declared to
1205    // find a previous declaration. This is the innermost enclosing namespace,
1206    // as described in ActOnFriendFunctionDecl.
1207    SemaRef.LookupQualifiedName(Previous, DC);
1208
1209    // In C++, the previous declaration we find might be a tag type
1210    // (class or enum). In this case, the new declaration will hide the
1211    // tag type. Note that this does does not apply if we're declaring a
1212    // typedef (C++ [dcl.typedef]p4).
1213    if (Previous.isSingleTagDecl())
1214      Previous.clear();
1215  }
1216
1217  SemaRef.CheckFunctionDeclaration(/*Scope*/ 0, Function, Previous,
1218                                   isExplicitSpecialization, Redeclaration);
1219
1220  NamedDecl *PrincipalDecl = (TemplateParams
1221                              ? cast<NamedDecl>(FunctionTemplate)
1222                              : Function);
1223
1224  // If the original function was part of a friend declaration,
1225  // inherit its namespace state and add it to the owner.
1226  if (isFriend) {
1227    NamedDecl *PrevDecl;
1228    if (TemplateParams)
1229      PrevDecl = FunctionTemplate->getPreviousDeclaration();
1230    else
1231      PrevDecl = Function->getPreviousDeclaration();
1232
1233    PrincipalDecl->setObjectOfFriendDecl(PrevDecl != 0);
1234    DC->makeDeclVisibleInContext(PrincipalDecl, /*Recoverable=*/ false);
1235
1236    bool queuedInstantiation = false;
1237
1238    if (!SemaRef.getLangOptions().CPlusPlus0x &&
1239        D->isThisDeclarationADefinition()) {
1240      // Check for a function body.
1241      const FunctionDecl *Definition = 0;
1242      if (Function->isDefined(Definition) &&
1243          Definition->getTemplateSpecializationKind() == TSK_Undeclared) {
1244        SemaRef.Diag(Function->getLocation(), diag::err_redefinition)
1245          << Function->getDeclName();
1246        SemaRef.Diag(Definition->getLocation(), diag::note_previous_definition);
1247        Function->setInvalidDecl();
1248      }
1249      // Check for redefinitions due to other instantiations of this or
1250      // a similar friend function.
1251      else for (FunctionDecl::redecl_iterator R = Function->redecls_begin(),
1252                                           REnd = Function->redecls_end();
1253                R != REnd; ++R) {
1254        if (*R == Function)
1255          continue;
1256        switch (R->getFriendObjectKind()) {
1257        case Decl::FOK_None:
1258          if (!queuedInstantiation && R->isUsed(false)) {
1259            if (MemberSpecializationInfo *MSInfo
1260                = Function->getMemberSpecializationInfo()) {
1261              if (MSInfo->getPointOfInstantiation().isInvalid()) {
1262                SourceLocation Loc = R->getLocation(); // FIXME
1263                MSInfo->setPointOfInstantiation(Loc);
1264                SemaRef.PendingLocalImplicitInstantiations.push_back(
1265                                                 std::make_pair(Function, Loc));
1266                queuedInstantiation = true;
1267              }
1268            }
1269          }
1270          break;
1271        default:
1272          if (const FunctionDecl *RPattern
1273              = R->getTemplateInstantiationPattern())
1274            if (RPattern->isDefined(RPattern)) {
1275              SemaRef.Diag(Function->getLocation(), diag::err_redefinition)
1276                << Function->getDeclName();
1277              SemaRef.Diag(R->getLocation(), diag::note_previous_definition);
1278              Function->setInvalidDecl();
1279              break;
1280            }
1281        }
1282      }
1283    }
1284  }
1285
1286  if (Function->isOverloadedOperator() && !DC->isRecord() &&
1287      PrincipalDecl->isInIdentifierNamespace(Decl::IDNS_Ordinary))
1288    PrincipalDecl->setNonMemberOperator();
1289
1290  assert(!D->isDefaulted() && "only methods should be defaulted");
1291  return Function;
1292}
1293
1294Decl *
1295TemplateDeclInstantiator::VisitCXXMethodDecl(CXXMethodDecl *D,
1296                                      TemplateParameterList *TemplateParams,
1297                                      bool IsClassScopeSpecialization) {
1298  FunctionTemplateDecl *FunctionTemplate = D->getDescribedFunctionTemplate();
1299  void *InsertPos = 0;
1300  if (FunctionTemplate && !TemplateParams) {
1301    // We are creating a function template specialization from a function
1302    // template. Check whether there is already a function template
1303    // specialization for this particular set of template arguments.
1304    std::pair<const TemplateArgument *, unsigned> Innermost
1305      = TemplateArgs.getInnermost();
1306
1307    FunctionDecl *SpecFunc
1308      = FunctionTemplate->findSpecialization(Innermost.first, Innermost.second,
1309                                             InsertPos);
1310
1311    // If we already have a function template specialization, return it.
1312    if (SpecFunc)
1313      return SpecFunc;
1314  }
1315
1316  bool isFriend;
1317  if (FunctionTemplate)
1318    isFriend = (FunctionTemplate->getFriendObjectKind() != Decl::FOK_None);
1319  else
1320    isFriend = (D->getFriendObjectKind() != Decl::FOK_None);
1321
1322  bool MergeWithParentScope = (TemplateParams != 0) ||
1323    !(isa<Decl>(Owner) &&
1324      cast<Decl>(Owner)->isDefinedOutsideFunctionOrMethod());
1325  LocalInstantiationScope Scope(SemaRef, MergeWithParentScope);
1326
1327  // Instantiate enclosing template arguments for friends.
1328  SmallVector<TemplateParameterList *, 4> TempParamLists;
1329  unsigned NumTempParamLists = 0;
1330  if (isFriend && (NumTempParamLists = D->getNumTemplateParameterLists())) {
1331    TempParamLists.set_size(NumTempParamLists);
1332    for (unsigned I = 0; I != NumTempParamLists; ++I) {
1333      TemplateParameterList *TempParams = D->getTemplateParameterList(I);
1334      TemplateParameterList *InstParams = SubstTemplateParams(TempParams);
1335      if (!InstParams)
1336        return NULL;
1337      TempParamLists[I] = InstParams;
1338    }
1339  }
1340
1341  SmallVector<ParmVarDecl *, 4> Params;
1342  TypeSourceInfo *TInfo = D->getTypeSourceInfo();
1343  TInfo = SubstFunctionType(D, Params);
1344  if (!TInfo)
1345    return 0;
1346  QualType T = TInfo->getType();
1347
1348  // \brief If the type of this function, after ignoring parentheses,
1349  // is not *directly* a function type, then we're instantiating a function
1350  // that was declared via a typedef, e.g.,
1351  //
1352  //   typedef int functype(int, int);
1353  //   functype func;
1354  //
1355  // In this case, we'll just go instantiate the ParmVarDecls that we
1356  // synthesized in the method declaration.
1357  if (!isa<FunctionProtoType>(T.IgnoreParens())) {
1358    assert(!Params.size() && "Instantiating type could not yield parameters");
1359    SmallVector<QualType, 4> ParamTypes;
1360    if (SemaRef.SubstParmTypes(D->getLocation(), D->param_begin(),
1361                               D->getNumParams(), TemplateArgs, ParamTypes,
1362                               &Params))
1363      return 0;
1364  }
1365
1366  NestedNameSpecifierLoc QualifierLoc = D->getQualifierLoc();
1367  if (QualifierLoc) {
1368    QualifierLoc = SemaRef.SubstNestedNameSpecifierLoc(QualifierLoc,
1369                                                 TemplateArgs);
1370    if (!QualifierLoc)
1371      return 0;
1372  }
1373
1374  DeclContext *DC = Owner;
1375  if (isFriend) {
1376    if (QualifierLoc) {
1377      CXXScopeSpec SS;
1378      SS.Adopt(QualifierLoc);
1379      DC = SemaRef.computeDeclContext(SS);
1380
1381      if (DC && SemaRef.RequireCompleteDeclContext(SS, DC))
1382        return 0;
1383    } else {
1384      DC = SemaRef.FindInstantiatedContext(D->getLocation(),
1385                                           D->getDeclContext(),
1386                                           TemplateArgs);
1387    }
1388    if (!DC) return 0;
1389  }
1390
1391  bool isConstexpr = D->isConstexpr();
1392  // FIXME: check whether the instantiation produces a constexpr function.
1393
1394  // Build the instantiated method declaration.
1395  CXXRecordDecl *Record = cast<CXXRecordDecl>(DC);
1396  CXXMethodDecl *Method = 0;
1397
1398  SourceLocation StartLoc = D->getInnerLocStart();
1399  DeclarationNameInfo NameInfo
1400    = SemaRef.SubstDeclarationNameInfo(D->getNameInfo(), TemplateArgs);
1401  if (CXXConstructorDecl *Constructor = dyn_cast<CXXConstructorDecl>(D)) {
1402    Method = CXXConstructorDecl::Create(SemaRef.Context, Record,
1403                                        StartLoc, NameInfo, T, TInfo,
1404                                        Constructor->isExplicit(),
1405                                        Constructor->isInlineSpecified(),
1406                                        false, isConstexpr);
1407  } else if (CXXDestructorDecl *Destructor = dyn_cast<CXXDestructorDecl>(D)) {
1408    Method = CXXDestructorDecl::Create(SemaRef.Context, Record,
1409                                       StartLoc, NameInfo, T, TInfo,
1410                                       Destructor->isInlineSpecified(),
1411                                       false);
1412  } else if (CXXConversionDecl *Conversion = dyn_cast<CXXConversionDecl>(D)) {
1413    Method = CXXConversionDecl::Create(SemaRef.Context, Record,
1414                                       StartLoc, NameInfo, T, TInfo,
1415                                       Conversion->isInlineSpecified(),
1416                                       Conversion->isExplicit(),
1417                                       isConstexpr, Conversion->getLocEnd());
1418  } else {
1419    Method = CXXMethodDecl::Create(SemaRef.Context, Record,
1420                                   StartLoc, NameInfo, T, TInfo,
1421                                   D->isStatic(),
1422                                   D->getStorageClassAsWritten(),
1423                                   D->isInlineSpecified(),
1424                                   isConstexpr, D->getLocEnd());
1425  }
1426
1427  if (QualifierLoc)
1428    Method->setQualifierInfo(QualifierLoc);
1429
1430  if (TemplateParams) {
1431    // Our resulting instantiation is actually a function template, since we
1432    // are substituting only the outer template parameters. For example, given
1433    //
1434    //   template<typename T>
1435    //   struct X {
1436    //     template<typename U> void f(T, U);
1437    //   };
1438    //
1439    //   X<int> x;
1440    //
1441    // We are instantiating the member template "f" within X<int>, which means
1442    // substituting int for T, but leaving "f" as a member function template.
1443    // Build the function template itself.
1444    FunctionTemplate = FunctionTemplateDecl::Create(SemaRef.Context, Record,
1445                                                    Method->getLocation(),
1446                                                    Method->getDeclName(),
1447                                                    TemplateParams, Method);
1448    if (isFriend) {
1449      FunctionTemplate->setLexicalDeclContext(Owner);
1450      FunctionTemplate->setObjectOfFriendDecl(true);
1451    } else if (D->isOutOfLine())
1452      FunctionTemplate->setLexicalDeclContext(D->getLexicalDeclContext());
1453    Method->setDescribedFunctionTemplate(FunctionTemplate);
1454  } else if (FunctionTemplate) {
1455    // Record this function template specialization.
1456    std::pair<const TemplateArgument *, unsigned> Innermost
1457      = TemplateArgs.getInnermost();
1458    Method->setFunctionTemplateSpecialization(FunctionTemplate,
1459                         TemplateArgumentList::CreateCopy(SemaRef.Context,
1460                                                          Innermost.first,
1461                                                          Innermost.second),
1462                                              InsertPos);
1463  } else if (!isFriend) {
1464    // Record that this is an instantiation of a member function.
1465    Method->setInstantiationOfMemberFunction(D, TSK_ImplicitInstantiation);
1466  }
1467
1468  // If we are instantiating a member function defined
1469  // out-of-line, the instantiation will have the same lexical
1470  // context (which will be a namespace scope) as the template.
1471  if (isFriend) {
1472    if (NumTempParamLists)
1473      Method->setTemplateParameterListsInfo(SemaRef.Context,
1474                                            NumTempParamLists,
1475                                            TempParamLists.data());
1476
1477    Method->setLexicalDeclContext(Owner);
1478    Method->setObjectOfFriendDecl(true);
1479  } else if (D->isOutOfLine())
1480    Method->setLexicalDeclContext(D->getLexicalDeclContext());
1481
1482  // Attach the parameters
1483  for (unsigned P = 0; P < Params.size(); ++P)
1484    Params[P]->setOwningFunction(Method);
1485  Method->setParams(Params);
1486
1487  if (InitMethodInstantiation(Method, D))
1488    Method->setInvalidDecl();
1489
1490  LookupResult Previous(SemaRef, NameInfo, Sema::LookupOrdinaryName,
1491                        Sema::ForRedeclaration);
1492
1493  if (!FunctionTemplate || TemplateParams || isFriend) {
1494    SemaRef.LookupQualifiedName(Previous, Record);
1495
1496    // In C++, the previous declaration we find might be a tag type
1497    // (class or enum). In this case, the new declaration will hide the
1498    // tag type. Note that this does does not apply if we're declaring a
1499    // typedef (C++ [dcl.typedef]p4).
1500    if (Previous.isSingleTagDecl())
1501      Previous.clear();
1502  }
1503
1504  bool Redeclaration = false;
1505  if (!IsClassScopeSpecialization)
1506    SemaRef.CheckFunctionDeclaration(0, Method, Previous, false, Redeclaration);
1507
1508  if (D->isPure())
1509    SemaRef.CheckPureMethod(Method, SourceRange());
1510
1511  Method->setAccess(D->getAccess());
1512
1513  SemaRef.CheckOverrideControl(Method);
1514
1515  if (FunctionTemplate) {
1516    // If there's a function template, let our caller handle it.
1517  } else if (Method->isInvalidDecl() && !Previous.empty()) {
1518    // Don't hide a (potentially) valid declaration with an invalid one.
1519  } else {
1520    NamedDecl *DeclToAdd = (TemplateParams
1521                            ? cast<NamedDecl>(FunctionTemplate)
1522                            : Method);
1523    if (isFriend)
1524      Record->makeDeclVisibleInContext(DeclToAdd);
1525    else if (!IsClassScopeSpecialization)
1526      Owner->addDecl(DeclToAdd);
1527  }
1528
1529  if (D->isExplicitlyDefaulted()) {
1530    SemaRef.SetDeclDefaulted(Method, Method->getLocation());
1531  } else {
1532    assert(!D->isDefaulted() &&
1533           "should not implicitly default uninstantiated function");
1534  }
1535
1536  return Method;
1537}
1538
1539Decl *TemplateDeclInstantiator::VisitCXXConstructorDecl(CXXConstructorDecl *D) {
1540  return VisitCXXMethodDecl(D);
1541}
1542
1543Decl *TemplateDeclInstantiator::VisitCXXDestructorDecl(CXXDestructorDecl *D) {
1544  return VisitCXXMethodDecl(D);
1545}
1546
1547Decl *TemplateDeclInstantiator::VisitCXXConversionDecl(CXXConversionDecl *D) {
1548  return VisitCXXMethodDecl(D);
1549}
1550
1551ParmVarDecl *TemplateDeclInstantiator::VisitParmVarDecl(ParmVarDecl *D) {
1552  return SemaRef.SubstParmVarDecl(D, TemplateArgs, /*indexAdjustment*/ 0,
1553                                  llvm::Optional<unsigned>());
1554}
1555
1556Decl *TemplateDeclInstantiator::VisitTemplateTypeParmDecl(
1557                                                    TemplateTypeParmDecl *D) {
1558  // TODO: don't always clone when decls are refcounted.
1559  assert(D->getTypeForDecl()->isTemplateTypeParmType());
1560
1561  TemplateTypeParmDecl *Inst =
1562    TemplateTypeParmDecl::Create(SemaRef.Context, Owner,
1563                                 D->getLocStart(), D->getLocation(),
1564                                 D->getDepth() - TemplateArgs.getNumLevels(),
1565                                 D->getIndex(), D->getIdentifier(),
1566                                 D->wasDeclaredWithTypename(),
1567                                 D->isParameterPack());
1568  Inst->setAccess(AS_public);
1569
1570  if (D->hasDefaultArgument())
1571    Inst->setDefaultArgument(D->getDefaultArgumentInfo(), false);
1572
1573  // Introduce this template parameter's instantiation into the instantiation
1574  // scope.
1575  SemaRef.CurrentInstantiationScope->InstantiatedLocal(D, Inst);
1576
1577  return Inst;
1578}
1579
1580Decl *TemplateDeclInstantiator::VisitNonTypeTemplateParmDecl(
1581                                                 NonTypeTemplateParmDecl *D) {
1582  // Substitute into the type of the non-type template parameter.
1583  TypeLoc TL = D->getTypeSourceInfo()->getTypeLoc();
1584  SmallVector<TypeSourceInfo *, 4> ExpandedParameterPackTypesAsWritten;
1585  SmallVector<QualType, 4> ExpandedParameterPackTypes;
1586  bool IsExpandedParameterPack = false;
1587  TypeSourceInfo *DI;
1588  QualType T;
1589  bool Invalid = false;
1590
1591  if (D->isExpandedParameterPack()) {
1592    // The non-type template parameter pack is an already-expanded pack
1593    // expansion of types. Substitute into each of the expanded types.
1594    ExpandedParameterPackTypes.reserve(D->getNumExpansionTypes());
1595    ExpandedParameterPackTypesAsWritten.reserve(D->getNumExpansionTypes());
1596    for (unsigned I = 0, N = D->getNumExpansionTypes(); I != N; ++I) {
1597      TypeSourceInfo *NewDI =SemaRef.SubstType(D->getExpansionTypeSourceInfo(I),
1598                                               TemplateArgs,
1599                                               D->getLocation(),
1600                                               D->getDeclName());
1601      if (!NewDI)
1602        return 0;
1603
1604      ExpandedParameterPackTypesAsWritten.push_back(NewDI);
1605      QualType NewT =SemaRef.CheckNonTypeTemplateParameterType(NewDI->getType(),
1606                                                              D->getLocation());
1607      if (NewT.isNull())
1608        return 0;
1609      ExpandedParameterPackTypes.push_back(NewT);
1610    }
1611
1612    IsExpandedParameterPack = true;
1613    DI = D->getTypeSourceInfo();
1614    T = DI->getType();
1615  } else if (isa<PackExpansionTypeLoc>(TL)) {
1616    // The non-type template parameter pack's type is a pack expansion of types.
1617    // Determine whether we need to expand this parameter pack into separate
1618    // types.
1619    PackExpansionTypeLoc Expansion = cast<PackExpansionTypeLoc>(TL);
1620    TypeLoc Pattern = Expansion.getPatternLoc();
1621    SmallVector<UnexpandedParameterPack, 2> Unexpanded;
1622    SemaRef.collectUnexpandedParameterPacks(Pattern, Unexpanded);
1623
1624    // Determine whether the set of unexpanded parameter packs can and should
1625    // be expanded.
1626    bool Expand = true;
1627    bool RetainExpansion = false;
1628    llvm::Optional<unsigned> OrigNumExpansions
1629      = Expansion.getTypePtr()->getNumExpansions();
1630    llvm::Optional<unsigned> NumExpansions = OrigNumExpansions;
1631    if (SemaRef.CheckParameterPacksForExpansion(Expansion.getEllipsisLoc(),
1632                                                Pattern.getSourceRange(),
1633                                                Unexpanded,
1634                                                TemplateArgs,
1635                                                Expand, RetainExpansion,
1636                                                NumExpansions))
1637      return 0;
1638
1639    if (Expand) {
1640      for (unsigned I = 0; I != *NumExpansions; ++I) {
1641        Sema::ArgumentPackSubstitutionIndexRAII SubstIndex(SemaRef, I);
1642        TypeSourceInfo *NewDI = SemaRef.SubstType(Pattern, TemplateArgs,
1643                                                  D->getLocation(),
1644                                                  D->getDeclName());
1645        if (!NewDI)
1646          return 0;
1647
1648        ExpandedParameterPackTypesAsWritten.push_back(NewDI);
1649        QualType NewT = SemaRef.CheckNonTypeTemplateParameterType(
1650                                                              NewDI->getType(),
1651                                                              D->getLocation());
1652        if (NewT.isNull())
1653          return 0;
1654        ExpandedParameterPackTypes.push_back(NewT);
1655      }
1656
1657      // Note that we have an expanded parameter pack. The "type" of this
1658      // expanded parameter pack is the original expansion type, but callers
1659      // will end up using the expanded parameter pack types for type-checking.
1660      IsExpandedParameterPack = true;
1661      DI = D->getTypeSourceInfo();
1662      T = DI->getType();
1663    } else {
1664      // We cannot fully expand the pack expansion now, so substitute into the
1665      // pattern and create a new pack expansion type.
1666      Sema::ArgumentPackSubstitutionIndexRAII SubstIndex(SemaRef, -1);
1667      TypeSourceInfo *NewPattern = SemaRef.SubstType(Pattern, TemplateArgs,
1668                                                     D->getLocation(),
1669                                                     D->getDeclName());
1670      if (!NewPattern)
1671        return 0;
1672
1673      DI = SemaRef.CheckPackExpansion(NewPattern, Expansion.getEllipsisLoc(),
1674                                      NumExpansions);
1675      if (!DI)
1676        return 0;
1677
1678      T = DI->getType();
1679    }
1680  } else {
1681    // Simple case: substitution into a parameter that is not a parameter pack.
1682    DI = SemaRef.SubstType(D->getTypeSourceInfo(), TemplateArgs,
1683                           D->getLocation(), D->getDeclName());
1684    if (!DI)
1685      return 0;
1686
1687    // Check that this type is acceptable for a non-type template parameter.
1688    T = SemaRef.CheckNonTypeTemplateParameterType(DI->getType(),
1689                                                  D->getLocation());
1690    if (T.isNull()) {
1691      T = SemaRef.Context.IntTy;
1692      Invalid = true;
1693    }
1694  }
1695
1696  NonTypeTemplateParmDecl *Param;
1697  if (IsExpandedParameterPack)
1698    Param = NonTypeTemplateParmDecl::Create(SemaRef.Context, Owner,
1699                                            D->getInnerLocStart(),
1700                                            D->getLocation(),
1701                                    D->getDepth() - TemplateArgs.getNumLevels(),
1702                                            D->getPosition(),
1703                                            D->getIdentifier(), T,
1704                                            DI,
1705                                            ExpandedParameterPackTypes.data(),
1706                                            ExpandedParameterPackTypes.size(),
1707                                    ExpandedParameterPackTypesAsWritten.data());
1708  else
1709    Param = NonTypeTemplateParmDecl::Create(SemaRef.Context, Owner,
1710                                            D->getInnerLocStart(),
1711                                            D->getLocation(),
1712                                    D->getDepth() - TemplateArgs.getNumLevels(),
1713                                            D->getPosition(),
1714                                            D->getIdentifier(), T,
1715                                            D->isParameterPack(), DI);
1716
1717  Param->setAccess(AS_public);
1718  if (Invalid)
1719    Param->setInvalidDecl();
1720
1721  Param->setDefaultArgument(D->getDefaultArgument(), false);
1722
1723  // Introduce this template parameter's instantiation into the instantiation
1724  // scope.
1725  SemaRef.CurrentInstantiationScope->InstantiatedLocal(D, Param);
1726  return Param;
1727}
1728
1729Decl *
1730TemplateDeclInstantiator::VisitTemplateTemplateParmDecl(
1731                                                  TemplateTemplateParmDecl *D) {
1732  // Instantiate the template parameter list of the template template parameter.
1733  TemplateParameterList *TempParams = D->getTemplateParameters();
1734  TemplateParameterList *InstParams;
1735  {
1736    // Perform the actual substitution of template parameters within a new,
1737    // local instantiation scope.
1738    LocalInstantiationScope Scope(SemaRef);
1739    InstParams = SubstTemplateParams(TempParams);
1740    if (!InstParams)
1741      return NULL;
1742  }
1743
1744  // Build the template template parameter.
1745  TemplateTemplateParmDecl *Param
1746    = TemplateTemplateParmDecl::Create(SemaRef.Context, Owner, D->getLocation(),
1747                                   D->getDepth() - TemplateArgs.getNumLevels(),
1748                                       D->getPosition(), D->isParameterPack(),
1749                                       D->getIdentifier(), InstParams);
1750  Param->setDefaultArgument(D->getDefaultArgument(), false);
1751  Param->setAccess(AS_public);
1752
1753  // Introduce this template parameter's instantiation into the instantiation
1754  // scope.
1755  SemaRef.CurrentInstantiationScope->InstantiatedLocal(D, Param);
1756
1757  return Param;
1758}
1759
1760Decl *TemplateDeclInstantiator::VisitUsingDirectiveDecl(UsingDirectiveDecl *D) {
1761  // Using directives are never dependent (and never contain any types or
1762  // expressions), so they require no explicit instantiation work.
1763
1764  UsingDirectiveDecl *Inst
1765    = UsingDirectiveDecl::Create(SemaRef.Context, Owner, D->getLocation(),
1766                                 D->getNamespaceKeyLocation(),
1767                                 D->getQualifierLoc(),
1768                                 D->getIdentLocation(),
1769                                 D->getNominatedNamespace(),
1770                                 D->getCommonAncestor());
1771  Owner->addDecl(Inst);
1772  return Inst;
1773}
1774
1775Decl *TemplateDeclInstantiator::VisitUsingDecl(UsingDecl *D) {
1776
1777  // The nested name specifier may be dependent, for example
1778  //     template <typename T> struct t {
1779  //       struct s1 { T f1(); };
1780  //       struct s2 : s1 { using s1::f1; };
1781  //     };
1782  //     template struct t<int>;
1783  // Here, in using s1::f1, s1 refers to t<T>::s1;
1784  // we need to substitute for t<int>::s1.
1785  NestedNameSpecifierLoc QualifierLoc
1786    = SemaRef.SubstNestedNameSpecifierLoc(D->getQualifierLoc(),
1787                                          TemplateArgs);
1788  if (!QualifierLoc)
1789    return 0;
1790
1791  // The name info is non-dependent, so no transformation
1792  // is required.
1793  DeclarationNameInfo NameInfo = D->getNameInfo();
1794
1795  // We only need to do redeclaration lookups if we're in a class
1796  // scope (in fact, it's not really even possible in non-class
1797  // scopes).
1798  bool CheckRedeclaration = Owner->isRecord();
1799
1800  LookupResult Prev(SemaRef, NameInfo, Sema::LookupUsingDeclName,
1801                    Sema::ForRedeclaration);
1802
1803  UsingDecl *NewUD = UsingDecl::Create(SemaRef.Context, Owner,
1804                                       D->getUsingLocation(),
1805                                       QualifierLoc,
1806                                       NameInfo,
1807                                       D->isTypeName());
1808
1809  CXXScopeSpec SS;
1810  SS.Adopt(QualifierLoc);
1811  if (CheckRedeclaration) {
1812    Prev.setHideTags(false);
1813    SemaRef.LookupQualifiedName(Prev, Owner);
1814
1815    // Check for invalid redeclarations.
1816    if (SemaRef.CheckUsingDeclRedeclaration(D->getUsingLocation(),
1817                                            D->isTypeName(), SS,
1818                                            D->getLocation(), Prev))
1819      NewUD->setInvalidDecl();
1820
1821  }
1822
1823  if (!NewUD->isInvalidDecl() &&
1824      SemaRef.CheckUsingDeclQualifier(D->getUsingLocation(), SS,
1825                                      D->getLocation()))
1826    NewUD->setInvalidDecl();
1827
1828  SemaRef.Context.setInstantiatedFromUsingDecl(NewUD, D);
1829  NewUD->setAccess(D->getAccess());
1830  Owner->addDecl(NewUD);
1831
1832  // Don't process the shadow decls for an invalid decl.
1833  if (NewUD->isInvalidDecl())
1834    return NewUD;
1835
1836  bool isFunctionScope = Owner->isFunctionOrMethod();
1837
1838  // Process the shadow decls.
1839  for (UsingDecl::shadow_iterator I = D->shadow_begin(), E = D->shadow_end();
1840         I != E; ++I) {
1841    UsingShadowDecl *Shadow = *I;
1842    NamedDecl *InstTarget =
1843      cast_or_null<NamedDecl>(SemaRef.FindInstantiatedDecl(
1844                                                          Shadow->getLocation(),
1845                                                        Shadow->getTargetDecl(),
1846                                                           TemplateArgs));
1847    if (!InstTarget)
1848      return 0;
1849
1850    if (CheckRedeclaration &&
1851        SemaRef.CheckUsingShadowDecl(NewUD, InstTarget, Prev))
1852      continue;
1853
1854    UsingShadowDecl *InstShadow
1855      = SemaRef.BuildUsingShadowDecl(/*Scope*/ 0, NewUD, InstTarget);
1856    SemaRef.Context.setInstantiatedFromUsingShadowDecl(InstShadow, Shadow);
1857
1858    if (isFunctionScope)
1859      SemaRef.CurrentInstantiationScope->InstantiatedLocal(Shadow, InstShadow);
1860  }
1861
1862  return NewUD;
1863}
1864
1865Decl *TemplateDeclInstantiator::VisitUsingShadowDecl(UsingShadowDecl *D) {
1866  // Ignore these;  we handle them in bulk when processing the UsingDecl.
1867  return 0;
1868}
1869
1870Decl * TemplateDeclInstantiator
1871    ::VisitUnresolvedUsingTypenameDecl(UnresolvedUsingTypenameDecl *D) {
1872  NestedNameSpecifierLoc QualifierLoc
1873    = SemaRef.SubstNestedNameSpecifierLoc(D->getQualifierLoc(),
1874                                          TemplateArgs);
1875  if (!QualifierLoc)
1876    return 0;
1877
1878  CXXScopeSpec SS;
1879  SS.Adopt(QualifierLoc);
1880
1881  // Since NameInfo refers to a typename, it cannot be a C++ special name.
1882  // Hence, no tranformation is required for it.
1883  DeclarationNameInfo NameInfo(D->getDeclName(), D->getLocation());
1884  NamedDecl *UD =
1885    SemaRef.BuildUsingDeclaration(/*Scope*/ 0, D->getAccess(),
1886                                  D->getUsingLoc(), SS, NameInfo, 0,
1887                                  /*instantiation*/ true,
1888                                  /*typename*/ true, D->getTypenameLoc());
1889  if (UD)
1890    SemaRef.Context.setInstantiatedFromUsingDecl(cast<UsingDecl>(UD), D);
1891
1892  return UD;
1893}
1894
1895Decl * TemplateDeclInstantiator
1896    ::VisitUnresolvedUsingValueDecl(UnresolvedUsingValueDecl *D) {
1897  NestedNameSpecifierLoc QualifierLoc
1898      = SemaRef.SubstNestedNameSpecifierLoc(D->getQualifierLoc(), TemplateArgs);
1899  if (!QualifierLoc)
1900    return 0;
1901
1902  CXXScopeSpec SS;
1903  SS.Adopt(QualifierLoc);
1904
1905  DeclarationNameInfo NameInfo
1906    = SemaRef.SubstDeclarationNameInfo(D->getNameInfo(), TemplateArgs);
1907
1908  NamedDecl *UD =
1909    SemaRef.BuildUsingDeclaration(/*Scope*/ 0, D->getAccess(),
1910                                  D->getUsingLoc(), SS, NameInfo, 0,
1911                                  /*instantiation*/ true,
1912                                  /*typename*/ false, SourceLocation());
1913  if (UD)
1914    SemaRef.Context.setInstantiatedFromUsingDecl(cast<UsingDecl>(UD), D);
1915
1916  return UD;
1917}
1918
1919
1920Decl *TemplateDeclInstantiator::VisitClassScopeFunctionSpecializationDecl(
1921                                     ClassScopeFunctionSpecializationDecl *Decl) {
1922  CXXMethodDecl *OldFD = Decl->getSpecialization();
1923  CXXMethodDecl *NewFD = cast<CXXMethodDecl>(VisitCXXMethodDecl(OldFD, 0, true));
1924
1925  LookupResult Previous(SemaRef, NewFD->getNameInfo(), Sema::LookupOrdinaryName,
1926                        Sema::ForRedeclaration);
1927
1928  SemaRef.LookupQualifiedName(Previous, SemaRef.CurContext);
1929  if (SemaRef.CheckFunctionTemplateSpecialization(NewFD, 0, Previous)) {
1930    NewFD->setInvalidDecl();
1931    return NewFD;
1932  }
1933
1934  // Associate the specialization with the pattern.
1935  FunctionDecl *Specialization = cast<FunctionDecl>(Previous.getFoundDecl());
1936  assert(Specialization && "Class scope Specialization is null");
1937  SemaRef.Context.setClassScopeSpecializationPattern(Specialization, OldFD);
1938
1939  return NewFD;
1940}
1941
1942Decl *Sema::SubstDecl(Decl *D, DeclContext *Owner,
1943                      const MultiLevelTemplateArgumentList &TemplateArgs) {
1944  TemplateDeclInstantiator Instantiator(*this, Owner, TemplateArgs);
1945  if (D->isInvalidDecl())
1946    return 0;
1947
1948  return Instantiator.Visit(D);
1949}
1950
1951/// \brief Instantiates a nested template parameter list in the current
1952/// instantiation context.
1953///
1954/// \param L The parameter list to instantiate
1955///
1956/// \returns NULL if there was an error
1957TemplateParameterList *
1958TemplateDeclInstantiator::SubstTemplateParams(TemplateParameterList *L) {
1959  // Get errors for all the parameters before bailing out.
1960  bool Invalid = false;
1961
1962  unsigned N = L->size();
1963  typedef SmallVector<NamedDecl *, 8> ParamVector;
1964  ParamVector Params;
1965  Params.reserve(N);
1966  for (TemplateParameterList::iterator PI = L->begin(), PE = L->end();
1967       PI != PE; ++PI) {
1968    NamedDecl *D = cast_or_null<NamedDecl>(Visit(*PI));
1969    Params.push_back(D);
1970    Invalid = Invalid || !D || D->isInvalidDecl();
1971  }
1972
1973  // Clean up if we had an error.
1974  if (Invalid)
1975    return NULL;
1976
1977  TemplateParameterList *InstL
1978    = TemplateParameterList::Create(SemaRef.Context, L->getTemplateLoc(),
1979                                    L->getLAngleLoc(), &Params.front(), N,
1980                                    L->getRAngleLoc());
1981  return InstL;
1982}
1983
1984/// \brief Instantiate the declaration of a class template partial
1985/// specialization.
1986///
1987/// \param ClassTemplate the (instantiated) class template that is partially
1988// specialized by the instantiation of \p PartialSpec.
1989///
1990/// \param PartialSpec the (uninstantiated) class template partial
1991/// specialization that we are instantiating.
1992///
1993/// \returns The instantiated partial specialization, if successful; otherwise,
1994/// NULL to indicate an error.
1995ClassTemplatePartialSpecializationDecl *
1996TemplateDeclInstantiator::InstantiateClassTemplatePartialSpecialization(
1997                                            ClassTemplateDecl *ClassTemplate,
1998                          ClassTemplatePartialSpecializationDecl *PartialSpec) {
1999  // Create a local instantiation scope for this class template partial
2000  // specialization, which will contain the instantiations of the template
2001  // parameters.
2002  LocalInstantiationScope Scope(SemaRef);
2003
2004  // Substitute into the template parameters of the class template partial
2005  // specialization.
2006  TemplateParameterList *TempParams = PartialSpec->getTemplateParameters();
2007  TemplateParameterList *InstParams = SubstTemplateParams(TempParams);
2008  if (!InstParams)
2009    return 0;
2010
2011  // Substitute into the template arguments of the class template partial
2012  // specialization.
2013  TemplateArgumentListInfo InstTemplateArgs; // no angle locations
2014  if (SemaRef.Subst(PartialSpec->getTemplateArgsAsWritten(),
2015                    PartialSpec->getNumTemplateArgsAsWritten(),
2016                    InstTemplateArgs, TemplateArgs))
2017    return 0;
2018
2019  // Check that the template argument list is well-formed for this
2020  // class template.
2021  SmallVector<TemplateArgument, 4> Converted;
2022  if (SemaRef.CheckTemplateArgumentList(ClassTemplate,
2023                                        PartialSpec->getLocation(),
2024                                        InstTemplateArgs,
2025                                        false,
2026                                        Converted))
2027    return 0;
2028
2029  // Figure out where to insert this class template partial specialization
2030  // in the member template's set of class template partial specializations.
2031  void *InsertPos = 0;
2032  ClassTemplateSpecializationDecl *PrevDecl
2033    = ClassTemplate->findPartialSpecialization(Converted.data(),
2034                                               Converted.size(), InsertPos);
2035
2036  // Build the canonical type that describes the converted template
2037  // arguments of the class template partial specialization.
2038  QualType CanonType
2039    = SemaRef.Context.getTemplateSpecializationType(TemplateName(ClassTemplate),
2040                                                    Converted.data(),
2041                                                    Converted.size());
2042
2043  // Build the fully-sugared type for this class template
2044  // specialization as the user wrote in the specialization
2045  // itself. This means that we'll pretty-print the type retrieved
2046  // from the specialization's declaration the way that the user
2047  // actually wrote the specialization, rather than formatting the
2048  // name based on the "canonical" representation used to store the
2049  // template arguments in the specialization.
2050  TypeSourceInfo *WrittenTy
2051    = SemaRef.Context.getTemplateSpecializationTypeInfo(
2052                                                    TemplateName(ClassTemplate),
2053                                                    PartialSpec->getLocation(),
2054                                                    InstTemplateArgs,
2055                                                    CanonType);
2056
2057  if (PrevDecl) {
2058    // We've already seen a partial specialization with the same template
2059    // parameters and template arguments. This can happen, for example, when
2060    // substituting the outer template arguments ends up causing two
2061    // class template partial specializations of a member class template
2062    // to have identical forms, e.g.,
2063    //
2064    //   template<typename T, typename U>
2065    //   struct Outer {
2066    //     template<typename X, typename Y> struct Inner;
2067    //     template<typename Y> struct Inner<T, Y>;
2068    //     template<typename Y> struct Inner<U, Y>;
2069    //   };
2070    //
2071    //   Outer<int, int> outer; // error: the partial specializations of Inner
2072    //                          // have the same signature.
2073    SemaRef.Diag(PartialSpec->getLocation(), diag::err_partial_spec_redeclared)
2074      << WrittenTy->getType();
2075    SemaRef.Diag(PrevDecl->getLocation(), diag::note_prev_partial_spec_here)
2076      << SemaRef.Context.getTypeDeclType(PrevDecl);
2077    return 0;
2078  }
2079
2080
2081  // Create the class template partial specialization declaration.
2082  ClassTemplatePartialSpecializationDecl *InstPartialSpec
2083    = ClassTemplatePartialSpecializationDecl::Create(SemaRef.Context,
2084                                                     PartialSpec->getTagKind(),
2085                                                     Owner,
2086                                                     PartialSpec->getLocStart(),
2087                                                     PartialSpec->getLocation(),
2088                                                     InstParams,
2089                                                     ClassTemplate,
2090                                                     Converted.data(),
2091                                                     Converted.size(),
2092                                                     InstTemplateArgs,
2093                                                     CanonType,
2094                                                     0,
2095                             ClassTemplate->getNextPartialSpecSequenceNumber());
2096  // Substitute the nested name specifier, if any.
2097  if (SubstQualifier(PartialSpec, InstPartialSpec))
2098    return 0;
2099
2100  InstPartialSpec->setInstantiatedFromMember(PartialSpec);
2101  InstPartialSpec->setTypeAsWritten(WrittenTy);
2102
2103  // Add this partial specialization to the set of class template partial
2104  // specializations.
2105  ClassTemplate->AddPartialSpecialization(InstPartialSpec, InsertPos);
2106  return InstPartialSpec;
2107}
2108
2109TypeSourceInfo*
2110TemplateDeclInstantiator::SubstFunctionType(FunctionDecl *D,
2111                              SmallVectorImpl<ParmVarDecl *> &Params) {
2112  TypeSourceInfo *OldTInfo = D->getTypeSourceInfo();
2113  assert(OldTInfo && "substituting function without type source info");
2114  assert(Params.empty() && "parameter vector is non-empty at start");
2115  TypeSourceInfo *NewTInfo
2116    = SemaRef.SubstFunctionDeclType(OldTInfo, TemplateArgs,
2117                                    D->getTypeSpecStartLoc(),
2118                                    D->getDeclName());
2119  if (!NewTInfo)
2120    return 0;
2121
2122  if (NewTInfo != OldTInfo) {
2123    // Get parameters from the new type info.
2124    TypeLoc OldTL = OldTInfo->getTypeLoc().IgnoreParens();
2125    if (FunctionProtoTypeLoc *OldProtoLoc
2126                                  = dyn_cast<FunctionProtoTypeLoc>(&OldTL)) {
2127      TypeLoc NewTL = NewTInfo->getTypeLoc().IgnoreParens();
2128      FunctionProtoTypeLoc *NewProtoLoc = cast<FunctionProtoTypeLoc>(&NewTL);
2129      assert(NewProtoLoc && "Missing prototype?");
2130      unsigned NewIdx = 0, NumNewParams = NewProtoLoc->getNumArgs();
2131      for (unsigned OldIdx = 0, NumOldParams = OldProtoLoc->getNumArgs();
2132           OldIdx != NumOldParams; ++OldIdx) {
2133        ParmVarDecl *OldParam = OldProtoLoc->getArg(OldIdx);
2134        if (!OldParam->isParameterPack() ||
2135            (NewIdx < NumNewParams &&
2136             NewProtoLoc->getArg(NewIdx)->isParameterPack())) {
2137          // Simple case: normal parameter, or a parameter pack that's
2138          // instantiated to a (still-dependent) parameter pack.
2139          ParmVarDecl *NewParam = NewProtoLoc->getArg(NewIdx++);
2140          Params.push_back(NewParam);
2141          SemaRef.CurrentInstantiationScope->InstantiatedLocal(OldParam,
2142                                                               NewParam);
2143          continue;
2144        }
2145
2146        // Parameter pack: make the instantiation an argument pack.
2147        SemaRef.CurrentInstantiationScope->MakeInstantiatedLocalArgPack(
2148                                                                      OldParam);
2149        unsigned NumArgumentsInExpansion
2150          = SemaRef.getNumArgumentsInExpansion(OldParam->getType(),
2151                                               TemplateArgs);
2152        while (NumArgumentsInExpansion--) {
2153          ParmVarDecl *NewParam = NewProtoLoc->getArg(NewIdx++);
2154          Params.push_back(NewParam);
2155          SemaRef.CurrentInstantiationScope->InstantiatedLocalPackArg(OldParam,
2156                                                                      NewParam);
2157        }
2158      }
2159    }
2160  } else {
2161    // The function type itself was not dependent and therefore no
2162    // substitution occurred. However, we still need to instantiate
2163    // the function parameters themselves.
2164    TypeLoc OldTL = OldTInfo->getTypeLoc().IgnoreParens();
2165    if (FunctionProtoTypeLoc *OldProtoLoc
2166                                    = dyn_cast<FunctionProtoTypeLoc>(&OldTL)) {
2167      for (unsigned i = 0, i_end = OldProtoLoc->getNumArgs(); i != i_end; ++i) {
2168        ParmVarDecl *Parm = VisitParmVarDecl(OldProtoLoc->getArg(i));
2169        if (!Parm)
2170          return 0;
2171        Params.push_back(Parm);
2172      }
2173    }
2174  }
2175  return NewTInfo;
2176}
2177
2178/// \brief Initializes the common fields of an instantiation function
2179/// declaration (New) from the corresponding fields of its template (Tmpl).
2180///
2181/// \returns true if there was an error
2182bool
2183TemplateDeclInstantiator::InitFunctionInstantiation(FunctionDecl *New,
2184                                                    FunctionDecl *Tmpl) {
2185  if (Tmpl->isDeletedAsWritten())
2186    New->setDeletedAsWritten();
2187
2188  // If we are performing substituting explicitly-specified template arguments
2189  // or deduced template arguments into a function template and we reach this
2190  // point, we are now past the point where SFINAE applies and have committed
2191  // to keeping the new function template specialization. We therefore
2192  // convert the active template instantiation for the function template
2193  // into a template instantiation for this specific function template
2194  // specialization, which is not a SFINAE context, so that we diagnose any
2195  // further errors in the declaration itself.
2196  typedef Sema::ActiveTemplateInstantiation ActiveInstType;
2197  ActiveInstType &ActiveInst = SemaRef.ActiveTemplateInstantiations.back();
2198  if (ActiveInst.Kind == ActiveInstType::ExplicitTemplateArgumentSubstitution ||
2199      ActiveInst.Kind == ActiveInstType::DeducedTemplateArgumentSubstitution) {
2200    if (FunctionTemplateDecl *FunTmpl
2201          = dyn_cast<FunctionTemplateDecl>((Decl *)ActiveInst.Entity)) {
2202      assert(FunTmpl->getTemplatedDecl() == Tmpl &&
2203             "Deduction from the wrong function template?");
2204      (void) FunTmpl;
2205      ActiveInst.Kind = ActiveInstType::TemplateInstantiation;
2206      ActiveInst.Entity = reinterpret_cast<uintptr_t>(New);
2207      --SemaRef.NonInstantiationEntries;
2208    }
2209  }
2210
2211  const FunctionProtoType *Proto = Tmpl->getType()->getAs<FunctionProtoType>();
2212  assert(Proto && "Function template without prototype?");
2213
2214  if (Proto->hasExceptionSpec() || Proto->getNoReturnAttr()) {
2215    // The function has an exception specification or a "noreturn"
2216    // attribute. Substitute into each of the exception types.
2217    SmallVector<QualType, 4> Exceptions;
2218    for (unsigned I = 0, N = Proto->getNumExceptions(); I != N; ++I) {
2219      // FIXME: Poor location information!
2220      if (const PackExpansionType *PackExpansion
2221            = Proto->getExceptionType(I)->getAs<PackExpansionType>()) {
2222        // We have a pack expansion. Instantiate it.
2223        SmallVector<UnexpandedParameterPack, 2> Unexpanded;
2224        SemaRef.collectUnexpandedParameterPacks(PackExpansion->getPattern(),
2225                                                Unexpanded);
2226        assert(!Unexpanded.empty() &&
2227               "Pack expansion without parameter packs?");
2228
2229        bool Expand = false;
2230        bool RetainExpansion = false;
2231        llvm::Optional<unsigned> NumExpansions
2232                                          = PackExpansion->getNumExpansions();
2233        if (SemaRef.CheckParameterPacksForExpansion(New->getLocation(),
2234                                                    SourceRange(),
2235                                                    Unexpanded,
2236                                                    TemplateArgs,
2237                                                    Expand,
2238                                                    RetainExpansion,
2239                                                    NumExpansions))
2240          break;
2241
2242        if (!Expand) {
2243          // We can't expand this pack expansion into separate arguments yet;
2244          // just substitute into the pattern and create a new pack expansion
2245          // type.
2246          Sema::ArgumentPackSubstitutionIndexRAII SubstIndex(SemaRef, -1);
2247          QualType T = SemaRef.SubstType(PackExpansion->getPattern(),
2248                                         TemplateArgs,
2249                                       New->getLocation(), New->getDeclName());
2250          if (T.isNull())
2251            break;
2252
2253          T = SemaRef.Context.getPackExpansionType(T, NumExpansions);
2254          Exceptions.push_back(T);
2255          continue;
2256        }
2257
2258        // Substitute into the pack expansion pattern for each template
2259        bool Invalid = false;
2260        for (unsigned ArgIdx = 0; ArgIdx != *NumExpansions; ++ArgIdx) {
2261          Sema::ArgumentPackSubstitutionIndexRAII SubstIndex(SemaRef, ArgIdx);
2262
2263          QualType T = SemaRef.SubstType(PackExpansion->getPattern(),
2264                                         TemplateArgs,
2265                                       New->getLocation(), New->getDeclName());
2266          if (T.isNull()) {
2267            Invalid = true;
2268            break;
2269          }
2270
2271          Exceptions.push_back(T);
2272        }
2273
2274        if (Invalid)
2275          break;
2276
2277        continue;
2278      }
2279
2280      QualType T
2281        = SemaRef.SubstType(Proto->getExceptionType(I), TemplateArgs,
2282                            New->getLocation(), New->getDeclName());
2283      if (T.isNull() ||
2284          SemaRef.CheckSpecifiedExceptionType(T, New->getLocation()))
2285        continue;
2286
2287      Exceptions.push_back(T);
2288    }
2289    Expr *NoexceptExpr = 0;
2290    if (Expr *OldNoexceptExpr = Proto->getNoexceptExpr()) {
2291      EnterExpressionEvaluationContext Unevaluated(SemaRef, Sema::Unevaluated);
2292      ExprResult E = SemaRef.SubstExpr(OldNoexceptExpr, TemplateArgs);
2293      if (E.isUsable())
2294        NoexceptExpr = E.take();
2295    }
2296
2297    // Rebuild the function type
2298
2299    FunctionProtoType::ExtProtoInfo EPI = Proto->getExtProtoInfo();
2300    EPI.ExceptionSpecType = Proto->getExceptionSpecType();
2301    EPI.NumExceptions = Exceptions.size();
2302    EPI.Exceptions = Exceptions.data();
2303    EPI.NoexceptExpr = NoexceptExpr;
2304    EPI.ExtInfo = Proto->getExtInfo();
2305
2306    const FunctionProtoType *NewProto
2307      = New->getType()->getAs<FunctionProtoType>();
2308    assert(NewProto && "Template instantiation without function prototype?");
2309    New->setType(SemaRef.Context.getFunctionType(NewProto->getResultType(),
2310                                                 NewProto->arg_type_begin(),
2311                                                 NewProto->getNumArgs(),
2312                                                 EPI));
2313  }
2314
2315  const FunctionDecl* Definition = Tmpl;
2316
2317  // Get the definition. Leaves the variable unchanged if undefined.
2318  Tmpl->isDefined(Definition);
2319
2320  SemaRef.InstantiateAttrs(TemplateArgs, Definition, New);
2321
2322  return false;
2323}
2324
2325/// \brief Initializes common fields of an instantiated method
2326/// declaration (New) from the corresponding fields of its template
2327/// (Tmpl).
2328///
2329/// \returns true if there was an error
2330bool
2331TemplateDeclInstantiator::InitMethodInstantiation(CXXMethodDecl *New,
2332                                                  CXXMethodDecl *Tmpl) {
2333  if (InitFunctionInstantiation(New, Tmpl))
2334    return true;
2335
2336  New->setAccess(Tmpl->getAccess());
2337  if (Tmpl->isVirtualAsWritten())
2338    New->setVirtualAsWritten(true);
2339
2340  // FIXME: attributes
2341  // FIXME: New needs a pointer to Tmpl
2342  return false;
2343}
2344
2345/// \brief Instantiate the definition of the given function from its
2346/// template.
2347///
2348/// \param PointOfInstantiation the point at which the instantiation was
2349/// required. Note that this is not precisely a "point of instantiation"
2350/// for the function, but it's close.
2351///
2352/// \param Function the already-instantiated declaration of a
2353/// function template specialization or member function of a class template
2354/// specialization.
2355///
2356/// \param Recursive if true, recursively instantiates any functions that
2357/// are required by this instantiation.
2358///
2359/// \param DefinitionRequired if true, then we are performing an explicit
2360/// instantiation where the body of the function is required. Complain if
2361/// there is no such body.
2362void Sema::InstantiateFunctionDefinition(SourceLocation PointOfInstantiation,
2363                                         FunctionDecl *Function,
2364                                         bool Recursive,
2365                                         bool DefinitionRequired) {
2366  if (Function->isInvalidDecl() || Function->isDefined())
2367    return;
2368
2369  // Never instantiate an explicit specialization except if it is a class scope
2370  // explicit specialization.
2371  if (Function->getTemplateSpecializationKind() == TSK_ExplicitSpecialization &&
2372      !Function->getClassScopeSpecializationPattern())
2373    return;
2374
2375  // Find the function body that we'll be substituting.
2376  const FunctionDecl *PatternDecl = Function->getTemplateInstantiationPattern();
2377  assert(PatternDecl && "instantiating a non-template");
2378
2379  Stmt *Pattern = PatternDecl->getBody(PatternDecl);
2380  assert(PatternDecl && "template definition is not a template");
2381  if (!Pattern) {
2382    // Try to find a defaulted definition
2383    PatternDecl->isDefined(PatternDecl);
2384  }
2385  assert(PatternDecl && "template definition is not a template");
2386
2387  // Postpone late parsed template instantiations.
2388  if (PatternDecl->isLateTemplateParsed() &&
2389      !LateTemplateParser) {
2390    PendingInstantiations.push_back(
2391      std::make_pair(Function, PointOfInstantiation));
2392    return;
2393  }
2394
2395  // Call the LateTemplateParser callback if there a need to late parse
2396  // a templated function definition.
2397  if (!Pattern && PatternDecl->isLateTemplateParsed() &&
2398      LateTemplateParser) {
2399    LateTemplateParser(OpaqueParser, PatternDecl);
2400    Pattern = PatternDecl->getBody(PatternDecl);
2401  }
2402
2403  if (!Pattern && !PatternDecl->isDefaulted()) {
2404    if (DefinitionRequired) {
2405      if (Function->getPrimaryTemplate())
2406        Diag(PointOfInstantiation,
2407             diag::err_explicit_instantiation_undefined_func_template)
2408          << Function->getPrimaryTemplate();
2409      else
2410        Diag(PointOfInstantiation,
2411             diag::err_explicit_instantiation_undefined_member)
2412          << 1 << Function->getDeclName() << Function->getDeclContext();
2413
2414      if (PatternDecl)
2415        Diag(PatternDecl->getLocation(),
2416             diag::note_explicit_instantiation_here);
2417      Function->setInvalidDecl();
2418    } else if (Function->getTemplateSpecializationKind()
2419                 == TSK_ExplicitInstantiationDefinition) {
2420      PendingInstantiations.push_back(
2421        std::make_pair(Function, PointOfInstantiation));
2422    }
2423
2424    return;
2425  }
2426
2427  // C++0x [temp.explicit]p9:
2428  //   Except for inline functions, other explicit instantiation declarations
2429  //   have the effect of suppressing the implicit instantiation of the entity
2430  //   to which they refer.
2431  if (Function->getTemplateSpecializationKind()
2432        == TSK_ExplicitInstantiationDeclaration &&
2433      !PatternDecl->isInlined())
2434    return;
2435
2436  InstantiatingTemplate Inst(*this, PointOfInstantiation, Function);
2437  if (Inst)
2438    return;
2439
2440  // If we're performing recursive template instantiation, create our own
2441  // queue of pending implicit instantiations that we will instantiate later,
2442  // while we're still within our own instantiation context.
2443  SmallVector<VTableUse, 16> SavedVTableUses;
2444  std::deque<PendingImplicitInstantiation> SavedPendingInstantiations;
2445  if (Recursive) {
2446    VTableUses.swap(SavedVTableUses);
2447    PendingInstantiations.swap(SavedPendingInstantiations);
2448  }
2449
2450  EnterExpressionEvaluationContext EvalContext(*this,
2451                                               Sema::PotentiallyEvaluated);
2452  ActOnStartOfFunctionDef(0, Function);
2453
2454  // Introduce a new scope where local variable instantiations will be
2455  // recorded, unless we're actually a member function within a local
2456  // class, in which case we need to merge our results with the parent
2457  // scope (of the enclosing function).
2458  bool MergeWithParentScope = false;
2459  if (CXXRecordDecl *Rec = dyn_cast<CXXRecordDecl>(Function->getDeclContext()))
2460    MergeWithParentScope = Rec->isLocalClass();
2461
2462  LocalInstantiationScope Scope(*this, MergeWithParentScope);
2463
2464  // Introduce the instantiated function parameters into the local
2465  // instantiation scope, and set the parameter names to those used
2466  // in the template.
2467  unsigned FParamIdx = 0;
2468  for (unsigned I = 0, N = PatternDecl->getNumParams(); I != N; ++I) {
2469    const ParmVarDecl *PatternParam = PatternDecl->getParamDecl(I);
2470    if (!PatternParam->isParameterPack()) {
2471      // Simple case: not a parameter pack.
2472      assert(FParamIdx < Function->getNumParams());
2473      ParmVarDecl *FunctionParam = Function->getParamDecl(I);
2474      FunctionParam->setDeclName(PatternParam->getDeclName());
2475      Scope.InstantiatedLocal(PatternParam, FunctionParam);
2476      ++FParamIdx;
2477      continue;
2478    }
2479
2480    // Expand the parameter pack.
2481    Scope.MakeInstantiatedLocalArgPack(PatternParam);
2482    for (unsigned NumFParams = Function->getNumParams();
2483         FParamIdx < NumFParams;
2484         ++FParamIdx) {
2485      ParmVarDecl *FunctionParam = Function->getParamDecl(FParamIdx);
2486      FunctionParam->setDeclName(PatternParam->getDeclName());
2487      Scope.InstantiatedLocalPackArg(PatternParam, FunctionParam);
2488    }
2489  }
2490
2491  // Enter the scope of this instantiation. We don't use
2492  // PushDeclContext because we don't have a scope.
2493  Sema::ContextRAII savedContext(*this, Function);
2494
2495  MultiLevelTemplateArgumentList TemplateArgs =
2496    getTemplateInstantiationArgs(Function, 0, false, PatternDecl);
2497
2498  if (PatternDecl->isDefaulted()) {
2499    ActOnFinishFunctionBody(Function, 0, /*IsInstantiation=*/true);
2500
2501    SetDeclDefaulted(Function, PatternDecl->getLocation());
2502  } else {
2503    // If this is a constructor, instantiate the member initializers.
2504    if (const CXXConstructorDecl *Ctor =
2505          dyn_cast<CXXConstructorDecl>(PatternDecl)) {
2506      InstantiateMemInitializers(cast<CXXConstructorDecl>(Function), Ctor,
2507                                 TemplateArgs);
2508    }
2509
2510    // Instantiate the function body.
2511    StmtResult Body = SubstStmt(Pattern, TemplateArgs);
2512
2513    if (Body.isInvalid())
2514      Function->setInvalidDecl();
2515
2516    ActOnFinishFunctionBody(Function, Body.get(),
2517                            /*IsInstantiation=*/true);
2518  }
2519
2520  PerformDependentDiagnostics(PatternDecl, TemplateArgs);
2521
2522  savedContext.pop();
2523
2524  DeclGroupRef DG(Function);
2525  Consumer.HandleTopLevelDecl(DG);
2526
2527  // This class may have local implicit instantiations that need to be
2528  // instantiation within this scope.
2529  PerformPendingInstantiations(/*LocalOnly=*/true);
2530  Scope.Exit();
2531
2532  if (Recursive) {
2533    // Define any pending vtables.
2534    DefineUsedVTables();
2535
2536    // Instantiate any pending implicit instantiations found during the
2537    // instantiation of this template.
2538    PerformPendingInstantiations();
2539
2540    // Restore the set of pending vtables.
2541    assert(VTableUses.empty() &&
2542           "VTableUses should be empty before it is discarded.");
2543    VTableUses.swap(SavedVTableUses);
2544
2545    // Restore the set of pending implicit instantiations.
2546    assert(PendingInstantiations.empty() &&
2547           "PendingInstantiations should be empty before it is discarded.");
2548    PendingInstantiations.swap(SavedPendingInstantiations);
2549  }
2550}
2551
2552/// \brief Instantiate the definition of the given variable from its
2553/// template.
2554///
2555/// \param PointOfInstantiation the point at which the instantiation was
2556/// required. Note that this is not precisely a "point of instantiation"
2557/// for the function, but it's close.
2558///
2559/// \param Var the already-instantiated declaration of a static member
2560/// variable of a class template specialization.
2561///
2562/// \param Recursive if true, recursively instantiates any functions that
2563/// are required by this instantiation.
2564///
2565/// \param DefinitionRequired if true, then we are performing an explicit
2566/// instantiation where an out-of-line definition of the member variable
2567/// is required. Complain if there is no such definition.
2568void Sema::InstantiateStaticDataMemberDefinition(
2569                                          SourceLocation PointOfInstantiation,
2570                                                 VarDecl *Var,
2571                                                 bool Recursive,
2572                                                 bool DefinitionRequired) {
2573  if (Var->isInvalidDecl())
2574    return;
2575
2576  // Find the out-of-line definition of this static data member.
2577  VarDecl *Def = Var->getInstantiatedFromStaticDataMember();
2578  assert(Def && "This data member was not instantiated from a template?");
2579  assert(Def->isStaticDataMember() && "Not a static data member?");
2580  Def = Def->getOutOfLineDefinition();
2581
2582  if (!Def) {
2583    // We did not find an out-of-line definition of this static data member,
2584    // so we won't perform any instantiation. Rather, we rely on the user to
2585    // instantiate this definition (or provide a specialization for it) in
2586    // another translation unit.
2587    if (DefinitionRequired) {
2588      Def = Var->getInstantiatedFromStaticDataMember();
2589      Diag(PointOfInstantiation,
2590           diag::err_explicit_instantiation_undefined_member)
2591        << 2 << Var->getDeclName() << Var->getDeclContext();
2592      Diag(Def->getLocation(), diag::note_explicit_instantiation_here);
2593    } else if (Var->getTemplateSpecializationKind()
2594                 == TSK_ExplicitInstantiationDefinition) {
2595      PendingInstantiations.push_back(
2596        std::make_pair(Var, PointOfInstantiation));
2597    }
2598
2599    return;
2600  }
2601
2602  // Never instantiate an explicit specialization.
2603  if (Var->getTemplateSpecializationKind() == TSK_ExplicitSpecialization)
2604    return;
2605
2606  // C++0x [temp.explicit]p9:
2607  //   Except for inline functions, other explicit instantiation declarations
2608  //   have the effect of suppressing the implicit instantiation of the entity
2609  //   to which they refer.
2610  if (Var->getTemplateSpecializationKind()
2611        == TSK_ExplicitInstantiationDeclaration)
2612    return;
2613
2614  // If we already have a definition, we're done.
2615  if (Var->getDefinition())
2616    return;
2617
2618  InstantiatingTemplate Inst(*this, PointOfInstantiation, Var);
2619  if (Inst)
2620    return;
2621
2622  // If we're performing recursive template instantiation, create our own
2623  // queue of pending implicit instantiations that we will instantiate later,
2624  // while we're still within our own instantiation context.
2625  SmallVector<VTableUse, 16> SavedVTableUses;
2626  std::deque<PendingImplicitInstantiation> SavedPendingInstantiations;
2627  if (Recursive) {
2628    VTableUses.swap(SavedVTableUses);
2629    PendingInstantiations.swap(SavedPendingInstantiations);
2630  }
2631
2632  // Enter the scope of this instantiation. We don't use
2633  // PushDeclContext because we don't have a scope.
2634  ContextRAII previousContext(*this, Var->getDeclContext());
2635
2636  VarDecl *OldVar = Var;
2637  Var = cast_or_null<VarDecl>(SubstDecl(Def, Var->getDeclContext(),
2638                                        getTemplateInstantiationArgs(Var)));
2639
2640  previousContext.pop();
2641
2642  if (Var) {
2643    MemberSpecializationInfo *MSInfo = OldVar->getMemberSpecializationInfo();
2644    assert(MSInfo && "Missing member specialization information?");
2645    Var->setTemplateSpecializationKind(MSInfo->getTemplateSpecializationKind(),
2646                                       MSInfo->getPointOfInstantiation());
2647    DeclGroupRef DG(Var);
2648    Consumer.HandleTopLevelDecl(DG);
2649  }
2650
2651  if (Recursive) {
2652    // Define any newly required vtables.
2653    DefineUsedVTables();
2654
2655    // Instantiate any pending implicit instantiations found during the
2656    // instantiation of this template.
2657    PerformPendingInstantiations();
2658
2659    // Restore the set of pending vtables.
2660    assert(VTableUses.empty() &&
2661           "VTableUses should be empty before it is discarded, "
2662           "while instantiating static data member.");
2663    VTableUses.swap(SavedVTableUses);
2664
2665    // Restore the set of pending implicit instantiations.
2666    assert(PendingInstantiations.empty() &&
2667           "PendingInstantiations should be empty before it is discarded, "
2668           "while instantiating static data member.");
2669    PendingInstantiations.swap(SavedPendingInstantiations);
2670  }
2671}
2672
2673void
2674Sema::InstantiateMemInitializers(CXXConstructorDecl *New,
2675                                 const CXXConstructorDecl *Tmpl,
2676                           const MultiLevelTemplateArgumentList &TemplateArgs) {
2677
2678  SmallVector<CXXCtorInitializer*, 4> NewInits;
2679  bool AnyErrors = false;
2680
2681  // Instantiate all the initializers.
2682  for (CXXConstructorDecl::init_const_iterator Inits = Tmpl->init_begin(),
2683                                            InitsEnd = Tmpl->init_end();
2684       Inits != InitsEnd; ++Inits) {
2685    CXXCtorInitializer *Init = *Inits;
2686
2687    // Only instantiate written initializers, let Sema re-construct implicit
2688    // ones.
2689    if (!Init->isWritten())
2690      continue;
2691
2692    SourceLocation LParenLoc, RParenLoc;
2693    ASTOwningVector<Expr*> NewArgs(*this);
2694
2695    SourceLocation EllipsisLoc;
2696
2697    if (Init->isPackExpansion()) {
2698      // This is a pack expansion. We should expand it now.
2699      TypeLoc BaseTL = Init->getBaseClassInfo()->getTypeLoc();
2700      SmallVector<UnexpandedParameterPack, 2> Unexpanded;
2701      collectUnexpandedParameterPacks(BaseTL, Unexpanded);
2702      bool ShouldExpand = false;
2703      bool RetainExpansion = false;
2704      llvm::Optional<unsigned> NumExpansions;
2705      if (CheckParameterPacksForExpansion(Init->getEllipsisLoc(),
2706                                          BaseTL.getSourceRange(),
2707                                          Unexpanded,
2708                                          TemplateArgs, ShouldExpand,
2709                                          RetainExpansion,
2710                                          NumExpansions)) {
2711        AnyErrors = true;
2712        New->setInvalidDecl();
2713        continue;
2714      }
2715      assert(ShouldExpand && "Partial instantiation of base initializer?");
2716
2717      // Loop over all of the arguments in the argument pack(s),
2718      for (unsigned I = 0; I != *NumExpansions; ++I) {
2719        Sema::ArgumentPackSubstitutionIndexRAII SubstIndex(*this, I);
2720
2721        // Instantiate the initializer.
2722        if (InstantiateInitializer(Init->getInit(), TemplateArgs,
2723                                   LParenLoc, NewArgs, RParenLoc)) {
2724          AnyErrors = true;
2725          break;
2726        }
2727
2728        // Instantiate the base type.
2729        TypeSourceInfo *BaseTInfo = SubstType(Init->getBaseClassInfo(),
2730                                              TemplateArgs,
2731                                              Init->getSourceLocation(),
2732                                              New->getDeclName());
2733        if (!BaseTInfo) {
2734          AnyErrors = true;
2735          break;
2736        }
2737
2738        // Build the initializer.
2739        MemInitResult NewInit = BuildBaseInitializer(BaseTInfo->getType(),
2740                                                     BaseTInfo,
2741                                                     (Expr **)NewArgs.data(),
2742                                                     NewArgs.size(),
2743                                                     Init->getLParenLoc(),
2744                                                     Init->getRParenLoc(),
2745                                                     New->getParent(),
2746                                                     SourceLocation());
2747        if (NewInit.isInvalid()) {
2748          AnyErrors = true;
2749          break;
2750        }
2751
2752        NewInits.push_back(NewInit.get());
2753        NewArgs.clear();
2754      }
2755
2756      continue;
2757    }
2758
2759    // Instantiate the initializer.
2760    if (InstantiateInitializer(Init->getInit(), TemplateArgs,
2761                               LParenLoc, NewArgs, RParenLoc)) {
2762      AnyErrors = true;
2763      continue;
2764    }
2765
2766    MemInitResult NewInit;
2767    if (Init->isBaseInitializer()) {
2768      TypeSourceInfo *BaseTInfo = SubstType(Init->getBaseClassInfo(),
2769                                            TemplateArgs,
2770                                            Init->getSourceLocation(),
2771                                            New->getDeclName());
2772      if (!BaseTInfo) {
2773        AnyErrors = true;
2774        New->setInvalidDecl();
2775        continue;
2776      }
2777
2778      NewInit = BuildBaseInitializer(BaseTInfo->getType(), BaseTInfo,
2779                                     (Expr **)NewArgs.data(),
2780                                     NewArgs.size(),
2781                                     Init->getLParenLoc(),
2782                                     Init->getRParenLoc(),
2783                                     New->getParent(),
2784                                     EllipsisLoc);
2785    } else if (Init->isMemberInitializer()) {
2786      FieldDecl *Member = cast_or_null<FieldDecl>(FindInstantiatedDecl(
2787                                                     Init->getMemberLocation(),
2788                                                     Init->getMember(),
2789                                                     TemplateArgs));
2790      if (!Member) {
2791        AnyErrors = true;
2792        New->setInvalidDecl();
2793        continue;
2794      }
2795
2796      NewInit = BuildMemberInitializer(Member, (Expr **)NewArgs.data(),
2797                                       NewArgs.size(),
2798                                       Init->getSourceLocation(),
2799                                       Init->getLParenLoc(),
2800                                       Init->getRParenLoc());
2801    } else if (Init->isIndirectMemberInitializer()) {
2802      IndirectFieldDecl *IndirectMember =
2803         cast_or_null<IndirectFieldDecl>(FindInstantiatedDecl(
2804                                 Init->getMemberLocation(),
2805                                 Init->getIndirectMember(), TemplateArgs));
2806
2807      if (!IndirectMember) {
2808        AnyErrors = true;
2809        New->setInvalidDecl();
2810        continue;
2811      }
2812
2813      NewInit = BuildMemberInitializer(IndirectMember, (Expr **)NewArgs.data(),
2814                                       NewArgs.size(),
2815                                       Init->getSourceLocation(),
2816                                       Init->getLParenLoc(),
2817                                       Init->getRParenLoc());
2818    }
2819
2820    if (NewInit.isInvalid()) {
2821      AnyErrors = true;
2822      New->setInvalidDecl();
2823    } else {
2824      // FIXME: It would be nice if ASTOwningVector had a release function.
2825      NewArgs.take();
2826
2827      NewInits.push_back(NewInit.get());
2828    }
2829  }
2830
2831  // Assign all the initializers to the new constructor.
2832  ActOnMemInitializers(New,
2833                       /*FIXME: ColonLoc */
2834                       SourceLocation(),
2835                       NewInits.data(), NewInits.size(),
2836                       AnyErrors);
2837}
2838
2839// TODO: this could be templated if the various decl types used the
2840// same method name.
2841static bool isInstantiationOf(ClassTemplateDecl *Pattern,
2842                              ClassTemplateDecl *Instance) {
2843  Pattern = Pattern->getCanonicalDecl();
2844
2845  do {
2846    Instance = Instance->getCanonicalDecl();
2847    if (Pattern == Instance) return true;
2848    Instance = Instance->getInstantiatedFromMemberTemplate();
2849  } while (Instance);
2850
2851  return false;
2852}
2853
2854static bool isInstantiationOf(FunctionTemplateDecl *Pattern,
2855                              FunctionTemplateDecl *Instance) {
2856  Pattern = Pattern->getCanonicalDecl();
2857
2858  do {
2859    Instance = Instance->getCanonicalDecl();
2860    if (Pattern == Instance) return true;
2861    Instance = Instance->getInstantiatedFromMemberTemplate();
2862  } while (Instance);
2863
2864  return false;
2865}
2866
2867static bool
2868isInstantiationOf(ClassTemplatePartialSpecializationDecl *Pattern,
2869                  ClassTemplatePartialSpecializationDecl *Instance) {
2870  Pattern
2871    = cast<ClassTemplatePartialSpecializationDecl>(Pattern->getCanonicalDecl());
2872  do {
2873    Instance = cast<ClassTemplatePartialSpecializationDecl>(
2874                                                Instance->getCanonicalDecl());
2875    if (Pattern == Instance)
2876      return true;
2877    Instance = Instance->getInstantiatedFromMember();
2878  } while (Instance);
2879
2880  return false;
2881}
2882
2883static bool isInstantiationOf(CXXRecordDecl *Pattern,
2884                              CXXRecordDecl *Instance) {
2885  Pattern = Pattern->getCanonicalDecl();
2886
2887  do {
2888    Instance = Instance->getCanonicalDecl();
2889    if (Pattern == Instance) return true;
2890    Instance = Instance->getInstantiatedFromMemberClass();
2891  } while (Instance);
2892
2893  return false;
2894}
2895
2896static bool isInstantiationOf(FunctionDecl *Pattern,
2897                              FunctionDecl *Instance) {
2898  Pattern = Pattern->getCanonicalDecl();
2899
2900  do {
2901    Instance = Instance->getCanonicalDecl();
2902    if (Pattern == Instance) return true;
2903    Instance = Instance->getInstantiatedFromMemberFunction();
2904  } while (Instance);
2905
2906  return false;
2907}
2908
2909static bool isInstantiationOf(EnumDecl *Pattern,
2910                              EnumDecl *Instance) {
2911  Pattern = Pattern->getCanonicalDecl();
2912
2913  do {
2914    Instance = Instance->getCanonicalDecl();
2915    if (Pattern == Instance) return true;
2916    Instance = Instance->getInstantiatedFromMemberEnum();
2917  } while (Instance);
2918
2919  return false;
2920}
2921
2922static bool isInstantiationOf(UsingShadowDecl *Pattern,
2923                              UsingShadowDecl *Instance,
2924                              ASTContext &C) {
2925  return C.getInstantiatedFromUsingShadowDecl(Instance) == Pattern;
2926}
2927
2928static bool isInstantiationOf(UsingDecl *Pattern,
2929                              UsingDecl *Instance,
2930                              ASTContext &C) {
2931  return C.getInstantiatedFromUsingDecl(Instance) == Pattern;
2932}
2933
2934static bool isInstantiationOf(UnresolvedUsingValueDecl *Pattern,
2935                              UsingDecl *Instance,
2936                              ASTContext &C) {
2937  return C.getInstantiatedFromUsingDecl(Instance) == Pattern;
2938}
2939
2940static bool isInstantiationOf(UnresolvedUsingTypenameDecl *Pattern,
2941                              UsingDecl *Instance,
2942                              ASTContext &C) {
2943  return C.getInstantiatedFromUsingDecl(Instance) == Pattern;
2944}
2945
2946static bool isInstantiationOfStaticDataMember(VarDecl *Pattern,
2947                                              VarDecl *Instance) {
2948  assert(Instance->isStaticDataMember());
2949
2950  Pattern = Pattern->getCanonicalDecl();
2951
2952  do {
2953    Instance = Instance->getCanonicalDecl();
2954    if (Pattern == Instance) return true;
2955    Instance = Instance->getInstantiatedFromStaticDataMember();
2956  } while (Instance);
2957
2958  return false;
2959}
2960
2961// Other is the prospective instantiation
2962// D is the prospective pattern
2963static bool isInstantiationOf(ASTContext &Ctx, NamedDecl *D, Decl *Other) {
2964  if (D->getKind() != Other->getKind()) {
2965    if (UnresolvedUsingTypenameDecl *UUD
2966          = dyn_cast<UnresolvedUsingTypenameDecl>(D)) {
2967      if (UsingDecl *UD = dyn_cast<UsingDecl>(Other)) {
2968        return isInstantiationOf(UUD, UD, Ctx);
2969      }
2970    }
2971
2972    if (UnresolvedUsingValueDecl *UUD
2973          = dyn_cast<UnresolvedUsingValueDecl>(D)) {
2974      if (UsingDecl *UD = dyn_cast<UsingDecl>(Other)) {
2975        return isInstantiationOf(UUD, UD, Ctx);
2976      }
2977    }
2978
2979    return false;
2980  }
2981
2982  if (CXXRecordDecl *Record = dyn_cast<CXXRecordDecl>(Other))
2983    return isInstantiationOf(cast<CXXRecordDecl>(D), Record);
2984
2985  if (FunctionDecl *Function = dyn_cast<FunctionDecl>(Other))
2986    return isInstantiationOf(cast<FunctionDecl>(D), Function);
2987
2988  if (EnumDecl *Enum = dyn_cast<EnumDecl>(Other))
2989    return isInstantiationOf(cast<EnumDecl>(D), Enum);
2990
2991  if (VarDecl *Var = dyn_cast<VarDecl>(Other))
2992    if (Var->isStaticDataMember())
2993      return isInstantiationOfStaticDataMember(cast<VarDecl>(D), Var);
2994
2995  if (ClassTemplateDecl *Temp = dyn_cast<ClassTemplateDecl>(Other))
2996    return isInstantiationOf(cast<ClassTemplateDecl>(D), Temp);
2997
2998  if (FunctionTemplateDecl *Temp = dyn_cast<FunctionTemplateDecl>(Other))
2999    return isInstantiationOf(cast<FunctionTemplateDecl>(D), Temp);
3000
3001  if (ClassTemplatePartialSpecializationDecl *PartialSpec
3002        = dyn_cast<ClassTemplatePartialSpecializationDecl>(Other))
3003    return isInstantiationOf(cast<ClassTemplatePartialSpecializationDecl>(D),
3004                             PartialSpec);
3005
3006  if (FieldDecl *Field = dyn_cast<FieldDecl>(Other)) {
3007    if (!Field->getDeclName()) {
3008      // This is an unnamed field.
3009      return Ctx.getInstantiatedFromUnnamedFieldDecl(Field) ==
3010        cast<FieldDecl>(D);
3011    }
3012  }
3013
3014  if (UsingDecl *Using = dyn_cast<UsingDecl>(Other))
3015    return isInstantiationOf(cast<UsingDecl>(D), Using, Ctx);
3016
3017  if (UsingShadowDecl *Shadow = dyn_cast<UsingShadowDecl>(Other))
3018    return isInstantiationOf(cast<UsingShadowDecl>(D), Shadow, Ctx);
3019
3020  return D->getDeclName() && isa<NamedDecl>(Other) &&
3021    D->getDeclName() == cast<NamedDecl>(Other)->getDeclName();
3022}
3023
3024template<typename ForwardIterator>
3025static NamedDecl *findInstantiationOf(ASTContext &Ctx,
3026                                      NamedDecl *D,
3027                                      ForwardIterator first,
3028                                      ForwardIterator last) {
3029  for (; first != last; ++first)
3030    if (isInstantiationOf(Ctx, D, *first))
3031      return cast<NamedDecl>(*first);
3032
3033  return 0;
3034}
3035
3036/// \brief Finds the instantiation of the given declaration context
3037/// within the current instantiation.
3038///
3039/// \returns NULL if there was an error
3040DeclContext *Sema::FindInstantiatedContext(SourceLocation Loc, DeclContext* DC,
3041                          const MultiLevelTemplateArgumentList &TemplateArgs) {
3042  if (NamedDecl *D = dyn_cast<NamedDecl>(DC)) {
3043    Decl* ID = FindInstantiatedDecl(Loc, D, TemplateArgs);
3044    return cast_or_null<DeclContext>(ID);
3045  } else return DC;
3046}
3047
3048/// \brief Find the instantiation of the given declaration within the
3049/// current instantiation.
3050///
3051/// This routine is intended to be used when \p D is a declaration
3052/// referenced from within a template, that needs to mapped into the
3053/// corresponding declaration within an instantiation. For example,
3054/// given:
3055///
3056/// \code
3057/// template<typename T>
3058/// struct X {
3059///   enum Kind {
3060///     KnownValue = sizeof(T)
3061///   };
3062///
3063///   bool getKind() const { return KnownValue; }
3064/// };
3065///
3066/// template struct X<int>;
3067/// \endcode
3068///
3069/// In the instantiation of X<int>::getKind(), we need to map the
3070/// EnumConstantDecl for KnownValue (which refers to
3071/// X<T>::<Kind>::KnownValue) to its instantiation
3072/// (X<int>::<Kind>::KnownValue). InstantiateCurrentDeclRef() performs
3073/// this mapping from within the instantiation of X<int>.
3074NamedDecl *Sema::FindInstantiatedDecl(SourceLocation Loc, NamedDecl *D,
3075                          const MultiLevelTemplateArgumentList &TemplateArgs) {
3076  DeclContext *ParentDC = D->getDeclContext();
3077  if (isa<ParmVarDecl>(D) || isa<NonTypeTemplateParmDecl>(D) ||
3078      isa<TemplateTypeParmDecl>(D) || isa<TemplateTemplateParmDecl>(D) ||
3079      (ParentDC->isFunctionOrMethod() && ParentDC->isDependentContext())) {
3080    // D is a local of some kind. Look into the map of local
3081    // declarations to their instantiations.
3082    typedef LocalInstantiationScope::DeclArgumentPack DeclArgumentPack;
3083    llvm::PointerUnion<Decl *, DeclArgumentPack *> *Found
3084      = CurrentInstantiationScope->findInstantiationOf(D);
3085
3086    if (Found) {
3087      if (Decl *FD = Found->dyn_cast<Decl *>())
3088        return cast<NamedDecl>(FD);
3089
3090      unsigned PackIdx = ArgumentPackSubstitutionIndex;
3091      return cast<NamedDecl>((*Found->get<DeclArgumentPack *>())[PackIdx]);
3092    }
3093
3094    // If we didn't find the decl, then we must have a label decl that hasn't
3095    // been found yet.  Lazily instantiate it and return it now.
3096    assert(isa<LabelDecl>(D));
3097
3098    Decl *Inst = SubstDecl(D, CurContext, TemplateArgs);
3099    assert(Inst && "Failed to instantiate label??");
3100
3101    CurrentInstantiationScope->InstantiatedLocal(D, Inst);
3102    return cast<LabelDecl>(Inst);
3103  }
3104
3105  if (CXXRecordDecl *Record = dyn_cast<CXXRecordDecl>(D)) {
3106    if (!Record->isDependentContext())
3107      return D;
3108
3109    // If the RecordDecl is actually the injected-class-name or a
3110    // "templated" declaration for a class template, class template
3111    // partial specialization, or a member class of a class template,
3112    // substitute into the injected-class-name of the class template
3113    // or partial specialization to find the new DeclContext.
3114    QualType T;
3115    ClassTemplateDecl *ClassTemplate = Record->getDescribedClassTemplate();
3116
3117    if (ClassTemplate) {
3118      T = ClassTemplate->getInjectedClassNameSpecialization();
3119    } else if (ClassTemplatePartialSpecializationDecl *PartialSpec
3120                 = dyn_cast<ClassTemplatePartialSpecializationDecl>(Record)) {
3121      ClassTemplate = PartialSpec->getSpecializedTemplate();
3122
3123      // If we call SubstType with an InjectedClassNameType here we
3124      // can end up in an infinite loop.
3125      T = Context.getTypeDeclType(Record);
3126      assert(isa<InjectedClassNameType>(T) &&
3127             "type of partial specialization is not an InjectedClassNameType");
3128      T = cast<InjectedClassNameType>(T)->getInjectedSpecializationType();
3129    }
3130
3131    if (!T.isNull()) {
3132      // Substitute into the injected-class-name to get the type
3133      // corresponding to the instantiation we want, which may also be
3134      // the current instantiation (if we're in a template
3135      // definition). This substitution should never fail, since we
3136      // know we can instantiate the injected-class-name or we
3137      // wouldn't have gotten to the injected-class-name!
3138
3139      // FIXME: Can we use the CurrentInstantiationScope to avoid this
3140      // extra instantiation in the common case?
3141      T = SubstType(T, TemplateArgs, Loc, DeclarationName());
3142      assert(!T.isNull() && "Instantiation of injected-class-name cannot fail.");
3143
3144      if (!T->isDependentType()) {
3145        assert(T->isRecordType() && "Instantiation must produce a record type");
3146        return T->getAs<RecordType>()->getDecl();
3147      }
3148
3149      // We are performing "partial" template instantiation to create
3150      // the member declarations for the members of a class template
3151      // specialization. Therefore, D is actually referring to something
3152      // in the current instantiation. Look through the current
3153      // context, which contains actual instantiations, to find the
3154      // instantiation of the "current instantiation" that D refers
3155      // to.
3156      bool SawNonDependentContext = false;
3157      for (DeclContext *DC = CurContext; !DC->isFileContext();
3158           DC = DC->getParent()) {
3159        if (ClassTemplateSpecializationDecl *Spec
3160                          = dyn_cast<ClassTemplateSpecializationDecl>(DC))
3161          if (isInstantiationOf(ClassTemplate,
3162                                Spec->getSpecializedTemplate()))
3163            return Spec;
3164
3165        if (!DC->isDependentContext())
3166          SawNonDependentContext = true;
3167      }
3168
3169      // We're performing "instantiation" of a member of the current
3170      // instantiation while we are type-checking the
3171      // definition. Compute the declaration context and return that.
3172      assert(!SawNonDependentContext &&
3173             "No dependent context while instantiating record");
3174      DeclContext *DC = computeDeclContext(T);
3175      assert(DC &&
3176             "Unable to find declaration for the current instantiation");
3177      return cast<CXXRecordDecl>(DC);
3178    }
3179
3180    // Fall through to deal with other dependent record types (e.g.,
3181    // anonymous unions in class templates).
3182  }
3183
3184  if (!ParentDC->isDependentContext())
3185    return D;
3186
3187  ParentDC = FindInstantiatedContext(Loc, ParentDC, TemplateArgs);
3188  if (!ParentDC)
3189    return 0;
3190
3191  if (ParentDC != D->getDeclContext()) {
3192    // We performed some kind of instantiation in the parent context,
3193    // so now we need to look into the instantiated parent context to
3194    // find the instantiation of the declaration D.
3195
3196    // If our context used to be dependent, we may need to instantiate
3197    // it before performing lookup into that context.
3198    bool IsBeingInstantiated = false;
3199    if (CXXRecordDecl *Spec = dyn_cast<CXXRecordDecl>(ParentDC)) {
3200      if (!Spec->isDependentContext()) {
3201        QualType T = Context.getTypeDeclType(Spec);
3202        const RecordType *Tag = T->getAs<RecordType>();
3203        assert(Tag && "type of non-dependent record is not a RecordType");
3204        if (Tag->isBeingDefined())
3205          IsBeingInstantiated = true;
3206        if (!Tag->isBeingDefined() &&
3207            RequireCompleteType(Loc, T, diag::err_incomplete_type))
3208          return 0;
3209
3210        ParentDC = Tag->getDecl();
3211      }
3212    }
3213
3214    NamedDecl *Result = 0;
3215    if (D->getDeclName()) {
3216      DeclContext::lookup_result Found = ParentDC->lookup(D->getDeclName());
3217      Result = findInstantiationOf(Context, D, Found.first, Found.second);
3218    } else {
3219      // Since we don't have a name for the entity we're looking for,
3220      // our only option is to walk through all of the declarations to
3221      // find that name. This will occur in a few cases:
3222      //
3223      //   - anonymous struct/union within a template
3224      //   - unnamed class/struct/union/enum within a template
3225      //
3226      // FIXME: Find a better way to find these instantiations!
3227      Result = findInstantiationOf(Context, D,
3228                                   ParentDC->decls_begin(),
3229                                   ParentDC->decls_end());
3230    }
3231
3232    if (!Result) {
3233      if (isa<UsingShadowDecl>(D)) {
3234        // UsingShadowDecls can instantiate to nothing because of using hiding.
3235      } else if (Diags.hasErrorOccurred()) {
3236        // We've already complained about something, so most likely this
3237        // declaration failed to instantiate. There's no point in complaining
3238        // further, since this is normal in invalid code.
3239      } else if (IsBeingInstantiated) {
3240        // The class in which this member exists is currently being
3241        // instantiated, and we haven't gotten around to instantiating this
3242        // member yet. This can happen when the code uses forward declarations
3243        // of member classes, and introduces ordering dependencies via
3244        // template instantiation.
3245        Diag(Loc, diag::err_member_not_yet_instantiated)
3246          << D->getDeclName()
3247          << Context.getTypeDeclType(cast<CXXRecordDecl>(ParentDC));
3248        Diag(D->getLocation(), diag::note_non_instantiated_member_here);
3249      } else {
3250        // We should have found something, but didn't.
3251        llvm_unreachable("Unable to find instantiation of declaration!");
3252      }
3253    }
3254
3255    D = Result;
3256  }
3257
3258  return D;
3259}
3260
3261/// \brief Performs template instantiation for all implicit template
3262/// instantiations we have seen until this point.
3263void Sema::PerformPendingInstantiations(bool LocalOnly) {
3264  // Load pending instantiations from the external source.
3265  if (!LocalOnly && ExternalSource) {
3266    SmallVector<std::pair<ValueDecl *, SourceLocation>, 4> Pending;
3267    ExternalSource->ReadPendingInstantiations(Pending);
3268    PendingInstantiations.insert(PendingInstantiations.begin(),
3269                                 Pending.begin(), Pending.end());
3270  }
3271
3272  while (!PendingLocalImplicitInstantiations.empty() ||
3273         (!LocalOnly && !PendingInstantiations.empty())) {
3274    PendingImplicitInstantiation Inst;
3275
3276    if (PendingLocalImplicitInstantiations.empty()) {
3277      Inst = PendingInstantiations.front();
3278      PendingInstantiations.pop_front();
3279    } else {
3280      Inst = PendingLocalImplicitInstantiations.front();
3281      PendingLocalImplicitInstantiations.pop_front();
3282    }
3283
3284    // Instantiate function definitions
3285    if (FunctionDecl *Function = dyn_cast<FunctionDecl>(Inst.first)) {
3286      PrettyDeclStackTraceEntry CrashInfo(*this, Function, SourceLocation(),
3287                                          "instantiating function definition");
3288      bool DefinitionRequired = Function->getTemplateSpecializationKind() ==
3289                                TSK_ExplicitInstantiationDefinition;
3290      InstantiateFunctionDefinition(/*FIXME:*/Inst.second, Function, true,
3291                                    DefinitionRequired);
3292      continue;
3293    }
3294
3295    // Instantiate static data member definitions.
3296    VarDecl *Var = cast<VarDecl>(Inst.first);
3297    assert(Var->isStaticDataMember() && "Not a static data member?");
3298
3299    // Don't try to instantiate declarations if the most recent redeclaration
3300    // is invalid.
3301    if (Var->getMostRecentDeclaration()->isInvalidDecl())
3302      continue;
3303
3304    // Check if the most recent declaration has changed the specialization kind
3305    // and removed the need for implicit instantiation.
3306    switch (Var->getMostRecentDeclaration()->getTemplateSpecializationKind()) {
3307    case TSK_Undeclared:
3308      llvm_unreachable("Cannot instantitiate an undeclared specialization.");
3309    case TSK_ExplicitInstantiationDeclaration:
3310    case TSK_ExplicitSpecialization:
3311      continue;  // No longer need to instantiate this type.
3312    case TSK_ExplicitInstantiationDefinition:
3313      // We only need an instantiation if the pending instantiation *is* the
3314      // explicit instantiation.
3315      if (Var != Var->getMostRecentDeclaration()) continue;
3316    case TSK_ImplicitInstantiation:
3317      break;
3318    }
3319
3320    PrettyDeclStackTraceEntry CrashInfo(*this, Var, Var->getLocation(),
3321                                        "instantiating static data member "
3322                                        "definition");
3323
3324    bool DefinitionRequired = Var->getTemplateSpecializationKind() ==
3325                              TSK_ExplicitInstantiationDefinition;
3326    InstantiateStaticDataMemberDefinition(/*FIXME:*/Inst.second, Var, true,
3327                                          DefinitionRequired);
3328  }
3329}
3330
3331void Sema::PerformDependentDiagnostics(const DeclContext *Pattern,
3332                       const MultiLevelTemplateArgumentList &TemplateArgs) {
3333  for (DeclContext::ddiag_iterator I = Pattern->ddiag_begin(),
3334         E = Pattern->ddiag_end(); I != E; ++I) {
3335    DependentDiagnostic *DD = *I;
3336
3337    switch (DD->getKind()) {
3338    case DependentDiagnostic::Access:
3339      HandleDependentAccessCheck(*DD, TemplateArgs);
3340      break;
3341    }
3342  }
3343}
3344