SemaTemplateInstantiateDecl.cpp revision 1d441ee69aaf3b3afa4521d05df934c5c7ea5f62 
1//===--- SemaTemplateInstantiateDecl.cpp - C++ Template Decl Instantiation ===/
2//
3//                     The LLVM Compiler Infrastructure
4//
5// This file is distributed under the University of Illinois Open Source
6// License. See LICENSE.TXT for details.
7//===----------------------------------------------------------------------===/
8//
9//  This file implements C++ template instantiation for declarations.
10//
11//===----------------------------------------------------------------------===/
12#include "clang/Sema/SemaInternal.h"
13#include "clang/Sema/Lookup.h"
14#include "clang/Sema/PrettyDeclStackTrace.h"
15#include "clang/Sema/Template.h"
16#include "clang/AST/ASTConsumer.h"
17#include "clang/AST/ASTContext.h"
18#include "clang/AST/DeclTemplate.h"
19#include "clang/AST/DeclVisitor.h"
20#include "clang/AST/DependentDiagnostic.h"
21#include "clang/AST/Expr.h"
22#include "clang/AST/ExprCXX.h"
23#include "clang/AST/TypeLoc.h"
24#include "clang/Lex/Preprocessor.h"
25
26using namespace clang;
27
28bool TemplateDeclInstantiator::SubstQualifier(const DeclaratorDecl *OldDecl,
29                                              DeclaratorDecl *NewDecl) {
30  if (!OldDecl->getQualifierLoc())
31    return false;
32
33  NestedNameSpecifierLoc NewQualifierLoc
34    = SemaRef.SubstNestedNameSpecifierLoc(OldDecl->getQualifierLoc(),
35                                          TemplateArgs);
36
37  if (!NewQualifierLoc)
38    return true;
39
40  NewDecl->setQualifierInfo(NewQualifierLoc);
41  return false;
42}
43
44bool TemplateDeclInstantiator::SubstQualifier(const TagDecl *OldDecl,
45                                              TagDecl *NewDecl) {
46  if (!OldDecl->getQualifierLoc())
47    return false;
48
49  NestedNameSpecifierLoc NewQualifierLoc
50  = SemaRef.SubstNestedNameSpecifierLoc(OldDecl->getQualifierLoc(),
51                                        TemplateArgs);
52
53  if (!NewQualifierLoc)
54    return true;
55
56  NewDecl->setQualifierInfo(NewQualifierLoc);
57  return false;
58}
59
60// FIXME: Is this still too simple?
61void Sema::InstantiateAttrs(const MultiLevelTemplateArgumentList &TemplateArgs,
62                            Decl *Tmpl, Decl *New) {
63  for (AttrVec::const_iterator i = Tmpl->attr_begin(), e = Tmpl->attr_end();
64       i != e; ++i) {
65    const Attr *TmplAttr = *i;
66    // FIXME: This should be generalized to more than just the AlignedAttr.
67    if (const AlignedAttr *Aligned = dyn_cast<AlignedAttr>(TmplAttr)) {
68      if (Aligned->isAlignmentDependent()) {
69        // The alignment expression is not potentially evaluated.
70        EnterExpressionEvaluationContext Unevaluated(*this,
71                                                     Sema::Unevaluated);
72
73        if (Aligned->isAlignmentExpr()) {
74          ExprResult Result = SubstExpr(Aligned->getAlignmentExpr(),
75                                        TemplateArgs);
76          if (!Result.isInvalid())
77            AddAlignedAttr(Aligned->getLocation(), New, Result.takeAs<Expr>());
78        }
79        else {
80          TypeSourceInfo *Result = SubstType(Aligned->getAlignmentType(),
81                                             TemplateArgs,
82                                             Aligned->getLocation(),
83                                             DeclarationName());
84          if (Result)
85            AddAlignedAttr(Aligned->getLocation(), New, Result);
86        }
87        continue;
88      }
89    }
90
91    // FIXME: Is cloning correct for all attributes?
92    Attr *NewAttr = TmplAttr->clone(Context);
93    New->addAttr(NewAttr);
94  }
95}
96
97Decl *
98TemplateDeclInstantiator::VisitTranslationUnitDecl(TranslationUnitDecl *D) {
99  assert(false && "Translation units cannot be instantiated");
100  return D;
101}
102
103Decl *
104TemplateDeclInstantiator::VisitLabelDecl(LabelDecl *D) {
105  LabelDecl *Inst = LabelDecl::Create(SemaRef.Context, Owner, D->getLocation(),
106                                      D->getIdentifier());
107  Owner->addDecl(Inst);
108  return Inst;
109}
110
111Decl *
112TemplateDeclInstantiator::VisitNamespaceDecl(NamespaceDecl *D) {
113  assert(false && "Namespaces cannot be instantiated");
114  return D;
115}
116
117Decl *
118TemplateDeclInstantiator::VisitNamespaceAliasDecl(NamespaceAliasDecl *D) {
119  NamespaceAliasDecl *Inst
120    = NamespaceAliasDecl::Create(SemaRef.Context, Owner,
121                                 D->getNamespaceLoc(),
122                                 D->getAliasLoc(),
123                                 D->getIdentifier(),
124                                 D->getQualifierLoc(),
125                                 D->getTargetNameLoc(),
126                                 D->getNamespace());
127  Owner->addDecl(Inst);
128  return Inst;
129}
130
131Decl *TemplateDeclInstantiator::InstantiateTypedefNameDecl(TypedefNameDecl *D,
132                                                           bool IsTypeAlias) {
133  bool Invalid = false;
134  TypeSourceInfo *DI = D->getTypeSourceInfo();
135  if (DI->getType()->isDependentType() ||
136      DI->getType()->isVariablyModifiedType()) {
137    DI = SemaRef.SubstType(DI, TemplateArgs,
138                           D->getLocation(), D->getDeclName());
139    if (!DI) {
140      Invalid = true;
141      DI = SemaRef.Context.getTrivialTypeSourceInfo(SemaRef.Context.IntTy);
142    }
143  } else {
144    SemaRef.MarkDeclarationsReferencedInType(D->getLocation(), DI->getType());
145  }
146
147  // Create the new typedef
148  TypedefNameDecl *Typedef;
149  if (IsTypeAlias)
150    Typedef = TypeAliasDecl::Create(SemaRef.Context, Owner, D->getLocStart(),
151                                    D->getLocation(), D->getIdentifier(), DI);
152  else
153    Typedef = TypedefDecl::Create(SemaRef.Context, Owner, D->getLocStart(),
154                                  D->getLocation(), D->getIdentifier(), DI);
155  if (Invalid)
156    Typedef->setInvalidDecl();
157
158  // If the old typedef was the name for linkage purposes of an anonymous
159  // tag decl, re-establish that relationship for the new typedef.
160  if (const TagType *oldTagType = D->getUnderlyingType()->getAs<TagType>()) {
161    TagDecl *oldTag = oldTagType->getDecl();
162    if (oldTag->getTypedefNameForAnonDecl() == D) {
163      TagDecl *newTag = DI->getType()->castAs<TagType>()->getDecl();
164      assert(!newTag->getIdentifier() && !newTag->getTypedefNameForAnonDecl());
165      newTag->setTypedefNameForAnonDecl(Typedef);
166    }
167  }
168
169  if (TypedefNameDecl *Prev = D->getPreviousDeclaration()) {
170    NamedDecl *InstPrev = SemaRef.FindInstantiatedDecl(D->getLocation(), Prev,
171                                                       TemplateArgs);
172    if (!InstPrev)
173      return 0;
174
175    Typedef->setPreviousDeclaration(cast<TypedefNameDecl>(InstPrev));
176  }
177
178  SemaRef.InstantiateAttrs(TemplateArgs, D, Typedef);
179
180  Typedef->setAccess(D->getAccess());
181
182  return Typedef;
183}
184
185Decl *TemplateDeclInstantiator::VisitTypedefDecl(TypedefDecl *D) {
186  Decl *Typedef = InstantiateTypedefNameDecl(D, /*IsTypeAlias=*/false);
187  Owner->addDecl(Typedef);
188  return Typedef;
189}
190
191Decl *TemplateDeclInstantiator::VisitTypeAliasDecl(TypeAliasDecl *D) {
192  Decl *Typedef = InstantiateTypedefNameDecl(D, /*IsTypeAlias=*/true);
193  Owner->addDecl(Typedef);
194  return Typedef;
195}
196
197Decl *
198TemplateDeclInstantiator::VisitTypeAliasTemplateDecl(TypeAliasTemplateDecl *D) {
199  // Create a local instantiation scope for this type alias template, which
200  // will contain the instantiations of the template parameters.
201  LocalInstantiationScope Scope(SemaRef);
202
203  TemplateParameterList *TempParams = D->getTemplateParameters();
204  TemplateParameterList *InstParams = SubstTemplateParams(TempParams);
205  if (!InstParams)
206    return 0;
207
208  TypeAliasDecl *Pattern = D->getTemplatedDecl();
209
210  TypeAliasTemplateDecl *PrevAliasTemplate = 0;
211  if (Pattern->getPreviousDeclaration()) {
212    DeclContext::lookup_result Found = Owner->lookup(Pattern->getDeclName());
213    if (Found.first != Found.second) {
214      PrevAliasTemplate = dyn_cast<TypeAliasTemplateDecl>(*Found.first);
215    }
216  }
217
218  TypeAliasDecl *AliasInst = cast_or_null<TypeAliasDecl>(
219    InstantiateTypedefNameDecl(Pattern, /*IsTypeAlias=*/true));
220  if (!AliasInst)
221    return 0;
222
223  TypeAliasTemplateDecl *Inst
224    = TypeAliasTemplateDecl::Create(SemaRef.Context, Owner, D->getLocation(),
225                                    D->getDeclName(), InstParams, AliasInst);
226  if (PrevAliasTemplate)
227    Inst->setPreviousDeclaration(PrevAliasTemplate);
228
229  Inst->setAccess(D->getAccess());
230
231  if (!PrevAliasTemplate)
232    Inst->setInstantiatedFromMemberTemplate(D);
233
234  Owner->addDecl(Inst);
235
236  return Inst;
237}
238
239/// \brief Instantiate an initializer, breaking it into separate
240/// initialization arguments.
241///
242/// \param S The semantic analysis object.
243///
244/// \param Init The initializer to instantiate.
245///
246/// \param TemplateArgs Template arguments to be substituted into the
247/// initializer.
248///
249/// \param NewArgs Will be filled in with the instantiation arguments.
250///
251/// \returns true if an error occurred, false otherwise
252static bool InstantiateInitializer(Sema &S, Expr *Init,
253                            const MultiLevelTemplateArgumentList &TemplateArgs,
254                                   SourceLocation &LParenLoc,
255                                   ASTOwningVector<Expr*> &NewArgs,
256                                   SourceLocation &RParenLoc) {
257  NewArgs.clear();
258  LParenLoc = SourceLocation();
259  RParenLoc = SourceLocation();
260
261  if (!Init)
262    return false;
263
264  if (ExprWithCleanups *ExprTemp = dyn_cast<ExprWithCleanups>(Init))
265    Init = ExprTemp->getSubExpr();
266
267  while (CXXBindTemporaryExpr *Binder = dyn_cast<CXXBindTemporaryExpr>(Init))
268    Init = Binder->getSubExpr();
269
270  if (ImplicitCastExpr *ICE = dyn_cast<ImplicitCastExpr>(Init))
271    Init = ICE->getSubExprAsWritten();
272
273  if (ParenListExpr *ParenList = dyn_cast<ParenListExpr>(Init)) {
274    LParenLoc = ParenList->getLParenLoc();
275    RParenLoc = ParenList->getRParenLoc();
276    return S.SubstExprs(ParenList->getExprs(), ParenList->getNumExprs(),
277                        true, TemplateArgs, NewArgs);
278  }
279
280  if (CXXConstructExpr *Construct = dyn_cast<CXXConstructExpr>(Init)) {
281    if (!isa<CXXTemporaryObjectExpr>(Construct)) {
282      if (S.SubstExprs(Construct->getArgs(), Construct->getNumArgs(), true,
283                       TemplateArgs, NewArgs))
284        return true;
285
286      // FIXME: Fake locations!
287      LParenLoc = S.PP.getLocForEndOfToken(Init->getLocStart());
288      RParenLoc = LParenLoc;
289      return false;
290    }
291  }
292
293  ExprResult Result = S.SubstExpr(Init, TemplateArgs);
294  if (Result.isInvalid())
295    return true;
296
297  NewArgs.push_back(Result.takeAs<Expr>());
298  return false;
299}
300
301Decl *TemplateDeclInstantiator::VisitVarDecl(VarDecl *D) {
302  // If this is the variable for an anonymous struct or union,
303  // instantiate the anonymous struct/union type first.
304  if (const RecordType *RecordTy = D->getType()->getAs<RecordType>())
305    if (RecordTy->getDecl()->isAnonymousStructOrUnion())
306      if (!VisitCXXRecordDecl(cast<CXXRecordDecl>(RecordTy->getDecl())))
307        return 0;
308
309  // Do substitution on the type of the declaration
310  TypeSourceInfo *DI = SemaRef.SubstType(D->getTypeSourceInfo(),
311                                         TemplateArgs,
312                                         D->getTypeSpecStartLoc(),
313                                         D->getDeclName());
314  if (!DI)
315    return 0;
316
317  if (DI->getType()->isFunctionType()) {
318    SemaRef.Diag(D->getLocation(), diag::err_variable_instantiates_to_function)
319      << D->isStaticDataMember() << DI->getType();
320    return 0;
321  }
322
323  // Build the instantiated declaration
324  VarDecl *Var = VarDecl::Create(SemaRef.Context, Owner,
325                                 D->getInnerLocStart(),
326                                 D->getLocation(), D->getIdentifier(),
327                                 DI->getType(), DI,
328                                 D->getStorageClass(),
329                                 D->getStorageClassAsWritten());
330  Var->setThreadSpecified(D->isThreadSpecified());
331  Var->setCXXDirectInitializer(D->hasCXXDirectInitializer());
332  Var->setCXXForRangeDecl(D->isCXXForRangeDecl());
333
334  // Substitute the nested name specifier, if any.
335  if (SubstQualifier(D, Var))
336    return 0;
337
338  // If we are instantiating a static data member defined
339  // out-of-line, the instantiation will have the same lexical
340  // context (which will be a namespace scope) as the template.
341  if (D->isOutOfLine())
342    Var->setLexicalDeclContext(D->getLexicalDeclContext());
343
344  Var->setAccess(D->getAccess());
345
346  if (!D->isStaticDataMember()) {
347    Var->setUsed(D->isUsed(false));
348    Var->setReferenced(D->isReferenced());
349  }
350
351  // FIXME: In theory, we could have a previous declaration for variables that
352  // are not static data members.
353  bool Redeclaration = false;
354  // FIXME: having to fake up a LookupResult is dumb.
355  LookupResult Previous(SemaRef, Var->getDeclName(), Var->getLocation(),
356                        Sema::LookupOrdinaryName, Sema::ForRedeclaration);
357  if (D->isStaticDataMember())
358    SemaRef.LookupQualifiedName(Previous, Owner, false);
359  SemaRef.CheckVariableDeclaration(Var, Previous, Redeclaration);
360
361  if (D->isOutOfLine()) {
362    if (!D->isStaticDataMember())
363      D->getLexicalDeclContext()->addDecl(Var);
364    Owner->makeDeclVisibleInContext(Var);
365  } else {
366    Owner->addDecl(Var);
367    if (Owner->isFunctionOrMethod())
368      SemaRef.CurrentInstantiationScope->InstantiatedLocal(D, Var);
369  }
370  SemaRef.InstantiateAttrs(TemplateArgs, D, Var);
371
372  // Link instantiations of static data members back to the template from
373  // which they were instantiated.
374  if (Var->isStaticDataMember())
375    SemaRef.Context.setInstantiatedFromStaticDataMember(Var, D,
376                                                     TSK_ImplicitInstantiation);
377
378  if (Var->getAnyInitializer()) {
379    // We already have an initializer in the class.
380  } else if (D->getInit()) {
381    if (Var->isStaticDataMember() && !D->isOutOfLine())
382      SemaRef.PushExpressionEvaluationContext(Sema::Unevaluated);
383    else
384      SemaRef.PushExpressionEvaluationContext(Sema::PotentiallyEvaluated);
385
386    // Instantiate the initializer.
387    SourceLocation LParenLoc, RParenLoc;
388    ASTOwningVector<Expr*> InitArgs(SemaRef);
389    if (!InstantiateInitializer(SemaRef, D->getInit(), TemplateArgs, LParenLoc,
390                                InitArgs, RParenLoc)) {
391      bool TypeMayContainAuto = true;
392      // Attach the initializer to the declaration, if we have one.
393      if (InitArgs.size() == 0)
394        SemaRef.ActOnUninitializedDecl(Var, TypeMayContainAuto);
395      else if (D->hasCXXDirectInitializer()) {
396        // Add the direct initializer to the declaration.
397        SemaRef.AddCXXDirectInitializerToDecl(Var,
398                                              LParenLoc,
399                                              move_arg(InitArgs),
400                                              RParenLoc,
401                                              TypeMayContainAuto);
402      } else {
403        assert(InitArgs.size() == 1);
404        Expr *Init = InitArgs.take()[0];
405        SemaRef.AddInitializerToDecl(Var, Init, false, TypeMayContainAuto);
406      }
407    } else {
408      // FIXME: Not too happy about invalidating the declaration
409      // because of a bogus initializer.
410      Var->setInvalidDecl();
411    }
412
413    SemaRef.PopExpressionEvaluationContext();
414  } else if ((!Var->isStaticDataMember() || Var->isOutOfLine()) &&
415             !Var->isCXXForRangeDecl())
416    SemaRef.ActOnUninitializedDecl(Var, false);
417
418  // Diagnose unused local variables with dependent types, where the diagnostic
419  // will have been deferred.
420  if (!Var->isInvalidDecl() && Owner->isFunctionOrMethod() && !Var->isUsed() &&
421      D->getType()->isDependentType())
422    SemaRef.DiagnoseUnusedDecl(Var);
423
424  return Var;
425}
426
427Decl *TemplateDeclInstantiator::VisitAccessSpecDecl(AccessSpecDecl *D) {
428  AccessSpecDecl* AD
429    = AccessSpecDecl::Create(SemaRef.Context, D->getAccess(), Owner,
430                             D->getAccessSpecifierLoc(), D->getColonLoc());
431  Owner->addHiddenDecl(AD);
432  return AD;
433}
434
435Decl *TemplateDeclInstantiator::VisitFieldDecl(FieldDecl *D) {
436  bool Invalid = false;
437  TypeSourceInfo *DI = D->getTypeSourceInfo();
438  if (DI->getType()->isDependentType() ||
439      DI->getType()->isVariablyModifiedType())  {
440    DI = SemaRef.SubstType(DI, TemplateArgs,
441                           D->getLocation(), D->getDeclName());
442    if (!DI) {
443      DI = D->getTypeSourceInfo();
444      Invalid = true;
445    } else if (DI->getType()->isFunctionType()) {
446      // C++ [temp.arg.type]p3:
447      //   If a declaration acquires a function type through a type
448      //   dependent on a template-parameter and this causes a
449      //   declaration that does not use the syntactic form of a
450      //   function declarator to have function type, the program is
451      //   ill-formed.
452      SemaRef.Diag(D->getLocation(), diag::err_field_instantiates_to_function)
453        << DI->getType();
454      Invalid = true;
455    }
456  } else {
457    SemaRef.MarkDeclarationsReferencedInType(D->getLocation(), DI->getType());
458  }
459
460  Expr *BitWidth = D->getBitWidth();
461  if (Invalid)
462    BitWidth = 0;
463  else if (BitWidth) {
464    // The bit-width expression is not potentially evaluated.
465    EnterExpressionEvaluationContext Unevaluated(SemaRef, Sema::Unevaluated);
466
467    ExprResult InstantiatedBitWidth
468      = SemaRef.SubstExpr(BitWidth, TemplateArgs);
469    if (InstantiatedBitWidth.isInvalid()) {
470      Invalid = true;
471      BitWidth = 0;
472    } else
473      BitWidth = InstantiatedBitWidth.takeAs<Expr>();
474  }
475
476  FieldDecl *Field = SemaRef.CheckFieldDecl(D->getDeclName(),
477                                            DI->getType(), DI,
478                                            cast<RecordDecl>(Owner),
479                                            D->getLocation(),
480                                            D->isMutable(),
481                                            BitWidth,
482                                            D->hasInClassInitializer(),
483                                            D->getTypeSpecStartLoc(),
484                                            D->getAccess(),
485                                            0);
486  if (!Field) {
487    cast<Decl>(Owner)->setInvalidDecl();
488    return 0;
489  }
490
491  SemaRef.InstantiateAttrs(TemplateArgs, D, Field);
492
493  if (Invalid)
494    Field->setInvalidDecl();
495
496  if (!Field->getDeclName()) {
497    // Keep track of where this decl came from.
498    SemaRef.Context.setInstantiatedFromUnnamedFieldDecl(Field, D);
499  }
500  if (CXXRecordDecl *Parent= dyn_cast<CXXRecordDecl>(Field->getDeclContext())) {
501    if (Parent->isAnonymousStructOrUnion() &&
502        Parent->getRedeclContext()->isFunctionOrMethod())
503      SemaRef.CurrentInstantiationScope->InstantiatedLocal(D, Field);
504  }
505
506  Field->setImplicit(D->isImplicit());
507  Field->setAccess(D->getAccess());
508  Owner->addDecl(Field);
509
510  return Field;
511}
512
513Decl *TemplateDeclInstantiator::VisitIndirectFieldDecl(IndirectFieldDecl *D) {
514  NamedDecl **NamedChain =
515    new (SemaRef.Context)NamedDecl*[D->getChainingSize()];
516
517  int i = 0;
518  for (IndirectFieldDecl::chain_iterator PI =
519       D->chain_begin(), PE = D->chain_end();
520       PI != PE; ++PI) {
521    NamedDecl *Next = SemaRef.FindInstantiatedDecl(D->getLocation(), *PI,
522                                              TemplateArgs);
523    if (!Next)
524      return 0;
525
526    NamedChain[i++] = Next;
527  }
528
529  QualType T = cast<FieldDecl>(NamedChain[i-1])->getType();
530  IndirectFieldDecl* IndirectField
531    = IndirectFieldDecl::Create(SemaRef.Context, Owner, D->getLocation(),
532                                D->getIdentifier(), T,
533                                NamedChain, D->getChainingSize());
534
535
536  IndirectField->setImplicit(D->isImplicit());
537  IndirectField->setAccess(D->getAccess());
538  Owner->addDecl(IndirectField);
539  return IndirectField;
540}
541
542Decl *TemplateDeclInstantiator::VisitFriendDecl(FriendDecl *D) {
543  // Handle friend type expressions by simply substituting template
544  // parameters into the pattern type and checking the result.
545  if (TypeSourceInfo *Ty = D->getFriendType()) {
546    TypeSourceInfo *InstTy;
547    // If this is an unsupported friend, don't bother substituting template
548    // arguments into it. The actual type referred to won't be used by any
549    // parts of Clang, and may not be valid for instantiating. Just use the
550    // same info for the instantiated friend.
551    if (D->isUnsupportedFriend()) {
552      InstTy = Ty;
553    } else {
554      InstTy = SemaRef.SubstType(Ty, TemplateArgs,
555                                 D->getLocation(), DeclarationName());
556    }
557    if (!InstTy)
558      return 0;
559
560    FriendDecl *FD = SemaRef.CheckFriendTypeDecl(D->getFriendLoc(), InstTy);
561    if (!FD)
562      return 0;
563
564    FD->setAccess(AS_public);
565    FD->setUnsupportedFriend(D->isUnsupportedFriend());
566    Owner->addDecl(FD);
567    return FD;
568  }
569
570  NamedDecl *ND = D->getFriendDecl();
571  assert(ND && "friend decl must be a decl or a type!");
572
573  // All of the Visit implementations for the various potential friend
574  // declarations have to be carefully written to work for friend
575  // objects, with the most important detail being that the target
576  // decl should almost certainly not be placed in Owner.
577  Decl *NewND = Visit(ND);
578  if (!NewND) return 0;
579
580  FriendDecl *FD =
581    FriendDecl::Create(SemaRef.Context, Owner, D->getLocation(),
582                       cast<NamedDecl>(NewND), D->getFriendLoc());
583  FD->setAccess(AS_public);
584  FD->setUnsupportedFriend(D->isUnsupportedFriend());
585  Owner->addDecl(FD);
586  return FD;
587}
588
589Decl *TemplateDeclInstantiator::VisitStaticAssertDecl(StaticAssertDecl *D) {
590  Expr *AssertExpr = D->getAssertExpr();
591
592  // The expression in a static assertion is not potentially evaluated.
593  EnterExpressionEvaluationContext Unevaluated(SemaRef, Sema::Unevaluated);
594
595  ExprResult InstantiatedAssertExpr
596    = SemaRef.SubstExpr(AssertExpr, TemplateArgs);
597  if (InstantiatedAssertExpr.isInvalid())
598    return 0;
599
600  ExprResult Message(D->getMessage());
601  D->getMessage();
602  return SemaRef.ActOnStaticAssertDeclaration(D->getLocation(),
603                                              InstantiatedAssertExpr.get(),
604                                              Message.get(),
605                                              D->getRParenLoc());
606}
607
608Decl *TemplateDeclInstantiator::VisitEnumDecl(EnumDecl *D) {
609  EnumDecl *Enum = EnumDecl::Create(SemaRef.Context, Owner, D->getLocStart(),
610                                    D->getLocation(), D->getIdentifier(),
611                                    /*PrevDecl=*/0, D->isScoped(),
612                                    D->isScopedUsingClassTag(), D->isFixed());
613  if (D->isFixed()) {
614    if (TypeSourceInfo* TI = D->getIntegerTypeSourceInfo()) {
615      // If we have type source information for the underlying type, it means it
616      // has been explicitly set by the user. Perform substitution on it before
617      // moving on.
618      SourceLocation UnderlyingLoc = TI->getTypeLoc().getBeginLoc();
619      Enum->setIntegerTypeSourceInfo(SemaRef.SubstType(TI,
620                                                       TemplateArgs,
621                                                       UnderlyingLoc,
622                                                       DeclarationName()));
623
624      if (!Enum->getIntegerTypeSourceInfo())
625        Enum->setIntegerType(SemaRef.Context.IntTy);
626    }
627    else {
628      assert(!D->getIntegerType()->isDependentType()
629             && "Dependent type without type source info");
630      Enum->setIntegerType(D->getIntegerType());
631    }
632  }
633
634  SemaRef.InstantiateAttrs(TemplateArgs, D, Enum);
635
636  Enum->setInstantiationOfMemberEnum(D);
637  Enum->setAccess(D->getAccess());
638  if (SubstQualifier(D, Enum)) return 0;
639  Owner->addDecl(Enum);
640  Enum->startDefinition();
641
642  if (D->getDeclContext()->isFunctionOrMethod())
643    SemaRef.CurrentInstantiationScope->InstantiatedLocal(D, Enum);
644
645  llvm::SmallVector<Decl*, 4> Enumerators;
646
647  EnumConstantDecl *LastEnumConst = 0;
648  for (EnumDecl::enumerator_iterator EC = D->enumerator_begin(),
649         ECEnd = D->enumerator_end();
650       EC != ECEnd; ++EC) {
651    // The specified value for the enumerator.
652    ExprResult Value = SemaRef.Owned((Expr *)0);
653    if (Expr *UninstValue = EC->getInitExpr()) {
654      // The enumerator's value expression is not potentially evaluated.
655      EnterExpressionEvaluationContext Unevaluated(SemaRef,
656                                                   Sema::Unevaluated);
657
658      Value = SemaRef.SubstExpr(UninstValue, TemplateArgs);
659    }
660
661    // Drop the initial value and continue.
662    bool isInvalid = false;
663    if (Value.isInvalid()) {
664      Value = SemaRef.Owned((Expr *)0);
665      isInvalid = true;
666    }
667
668    EnumConstantDecl *EnumConst
669      = SemaRef.CheckEnumConstant(Enum, LastEnumConst,
670                                  EC->getLocation(), EC->getIdentifier(),
671                                  Value.get());
672
673    if (isInvalid) {
674      if (EnumConst)
675        EnumConst->setInvalidDecl();
676      Enum->setInvalidDecl();
677    }
678
679    if (EnumConst) {
680      SemaRef.InstantiateAttrs(TemplateArgs, *EC, EnumConst);
681
682      EnumConst->setAccess(Enum->getAccess());
683      Enum->addDecl(EnumConst);
684      Enumerators.push_back(EnumConst);
685      LastEnumConst = EnumConst;
686
687      if (D->getDeclContext()->isFunctionOrMethod()) {
688        // If the enumeration is within a function or method, record the enum
689        // constant as a local.
690        SemaRef.CurrentInstantiationScope->InstantiatedLocal(*EC, EnumConst);
691      }
692    }
693  }
694
695  // FIXME: Fixup LBraceLoc and RBraceLoc
696  // FIXME: Empty Scope and AttributeList (required to handle attribute packed).
697  SemaRef.ActOnEnumBody(Enum->getLocation(), SourceLocation(), SourceLocation(),
698                        Enum,
699                        Enumerators.data(), Enumerators.size(),
700                        0, 0);
701
702  return Enum;
703}
704
705Decl *TemplateDeclInstantiator::VisitEnumConstantDecl(EnumConstantDecl *D) {
706  assert(false && "EnumConstantDecls can only occur within EnumDecls.");
707  return 0;
708}
709
710Decl *TemplateDeclInstantiator::VisitClassTemplateDecl(ClassTemplateDecl *D) {
711  bool isFriend = (D->getFriendObjectKind() != Decl::FOK_None);
712
713  // Create a local instantiation scope for this class template, which
714  // will contain the instantiations of the template parameters.
715  LocalInstantiationScope Scope(SemaRef);
716  TemplateParameterList *TempParams = D->getTemplateParameters();
717  TemplateParameterList *InstParams = SubstTemplateParams(TempParams);
718  if (!InstParams)
719    return NULL;
720
721  CXXRecordDecl *Pattern = D->getTemplatedDecl();
722
723  // Instantiate the qualifier.  We have to do this first in case
724  // we're a friend declaration, because if we are then we need to put
725  // the new declaration in the appropriate context.
726  NestedNameSpecifierLoc QualifierLoc = Pattern->getQualifierLoc();
727  if (QualifierLoc) {
728    QualifierLoc = SemaRef.SubstNestedNameSpecifierLoc(QualifierLoc,
729                                                       TemplateArgs);
730    if (!QualifierLoc)
731      return 0;
732  }
733
734  CXXRecordDecl *PrevDecl = 0;
735  ClassTemplateDecl *PrevClassTemplate = 0;
736
737  if (!isFriend && Pattern->getPreviousDeclaration()) {
738    DeclContext::lookup_result Found = Owner->lookup(Pattern->getDeclName());
739    if (Found.first != Found.second) {
740      PrevClassTemplate = dyn_cast<ClassTemplateDecl>(*Found.first);
741      if (PrevClassTemplate)
742        PrevDecl = PrevClassTemplate->getTemplatedDecl();
743    }
744  }
745
746  // If this isn't a friend, then it's a member template, in which
747  // case we just want to build the instantiation in the
748  // specialization.  If it is a friend, we want to build it in
749  // the appropriate context.
750  DeclContext *DC = Owner;
751  if (isFriend) {
752    if (QualifierLoc) {
753      CXXScopeSpec SS;
754      SS.Adopt(QualifierLoc);
755      DC = SemaRef.computeDeclContext(SS);
756      if (!DC) return 0;
757    } else {
758      DC = SemaRef.FindInstantiatedContext(Pattern->getLocation(),
759                                           Pattern->getDeclContext(),
760                                           TemplateArgs);
761    }
762
763    // Look for a previous declaration of the template in the owning
764    // context.
765    LookupResult R(SemaRef, Pattern->getDeclName(), Pattern->getLocation(),
766                   Sema::LookupOrdinaryName, Sema::ForRedeclaration);
767    SemaRef.LookupQualifiedName(R, DC);
768
769    if (R.isSingleResult()) {
770      PrevClassTemplate = R.getAsSingle<ClassTemplateDecl>();
771      if (PrevClassTemplate)
772        PrevDecl = PrevClassTemplate->getTemplatedDecl();
773    }
774
775    if (!PrevClassTemplate && QualifierLoc) {
776      SemaRef.Diag(Pattern->getLocation(), diag::err_not_tag_in_scope)
777        << D->getTemplatedDecl()->getTagKind() << Pattern->getDeclName() << DC
778        << QualifierLoc.getSourceRange();
779      return 0;
780    }
781
782    bool AdoptedPreviousTemplateParams = false;
783    if (PrevClassTemplate) {
784      bool Complain = true;
785
786      // HACK: libstdc++ 4.2.1 contains an ill-formed friend class
787      // template for struct std::tr1::__detail::_Map_base, where the
788      // template parameters of the friend declaration don't match the
789      // template parameters of the original declaration. In this one
790      // case, we don't complain about the ill-formed friend
791      // declaration.
792      if (isFriend && Pattern->getIdentifier() &&
793          Pattern->getIdentifier()->isStr("_Map_base") &&
794          DC->isNamespace() &&
795          cast<NamespaceDecl>(DC)->getIdentifier() &&
796          cast<NamespaceDecl>(DC)->getIdentifier()->isStr("__detail")) {
797        DeclContext *DCParent = DC->getParent();
798        if (DCParent->isNamespace() &&
799            cast<NamespaceDecl>(DCParent)->getIdentifier() &&
800            cast<NamespaceDecl>(DCParent)->getIdentifier()->isStr("tr1")) {
801          DeclContext *DCParent2 = DCParent->getParent();
802          if (DCParent2->isNamespace() &&
803              cast<NamespaceDecl>(DCParent2)->getIdentifier() &&
804              cast<NamespaceDecl>(DCParent2)->getIdentifier()->isStr("std") &&
805              DCParent2->getParent()->isTranslationUnit())
806            Complain = false;
807        }
808      }
809
810      TemplateParameterList *PrevParams
811        = PrevClassTemplate->getTemplateParameters();
812
813      // Make sure the parameter lists match.
814      if (!SemaRef.TemplateParameterListsAreEqual(InstParams, PrevParams,
815                                                  Complain,
816                                                  Sema::TPL_TemplateMatch)) {
817        if (Complain)
818          return 0;
819
820        AdoptedPreviousTemplateParams = true;
821        InstParams = PrevParams;
822      }
823
824      // Do some additional validation, then merge default arguments
825      // from the existing declarations.
826      if (!AdoptedPreviousTemplateParams &&
827          SemaRef.CheckTemplateParameterList(InstParams, PrevParams,
828                                             Sema::TPC_ClassTemplate))
829        return 0;
830    }
831  }
832
833  CXXRecordDecl *RecordInst
834    = CXXRecordDecl::Create(SemaRef.Context, Pattern->getTagKind(), DC,
835                            Pattern->getLocStart(), Pattern->getLocation(),
836                            Pattern->getIdentifier(), PrevDecl,
837                            /*DelayTypeCreation=*/true);
838
839  if (QualifierLoc)
840    RecordInst->setQualifierInfo(QualifierLoc);
841
842  ClassTemplateDecl *Inst
843    = ClassTemplateDecl::Create(SemaRef.Context, DC, D->getLocation(),
844                                D->getIdentifier(), InstParams, RecordInst,
845                                PrevClassTemplate);
846  RecordInst->setDescribedClassTemplate(Inst);
847
848  if (isFriend) {
849    if (PrevClassTemplate)
850      Inst->setAccess(PrevClassTemplate->getAccess());
851    else
852      Inst->setAccess(D->getAccess());
853
854    Inst->setObjectOfFriendDecl(PrevClassTemplate != 0);
855    // TODO: do we want to track the instantiation progeny of this
856    // friend target decl?
857  } else {
858    Inst->setAccess(D->getAccess());
859    if (!PrevClassTemplate)
860      Inst->setInstantiatedFromMemberTemplate(D);
861  }
862
863  // Trigger creation of the type for the instantiation.
864  SemaRef.Context.getInjectedClassNameType(RecordInst,
865                                    Inst->getInjectedClassNameSpecialization());
866
867  // Finish handling of friends.
868  if (isFriend) {
869    DC->makeDeclVisibleInContext(Inst, /*Recoverable*/ false);
870    return Inst;
871  }
872
873  Owner->addDecl(Inst);
874
875  if (!PrevClassTemplate) {
876    // Queue up any out-of-line partial specializations of this member
877    // class template; the client will force their instantiation once
878    // the enclosing class has been instantiated.
879    llvm::SmallVector<ClassTemplatePartialSpecializationDecl *, 4> PartialSpecs;
880    D->getPartialSpecializations(PartialSpecs);
881    for (unsigned I = 0, N = PartialSpecs.size(); I != N; ++I)
882      if (PartialSpecs[I]->isOutOfLine())
883        OutOfLinePartialSpecs.push_back(std::make_pair(Inst, PartialSpecs[I]));
884  }
885
886  return Inst;
887}
888
889Decl *
890TemplateDeclInstantiator::VisitClassTemplatePartialSpecializationDecl(
891                                   ClassTemplatePartialSpecializationDecl *D) {
892  ClassTemplateDecl *ClassTemplate = D->getSpecializedTemplate();
893
894  // Lookup the already-instantiated declaration in the instantiation
895  // of the class template and return that.
896  DeclContext::lookup_result Found
897    = Owner->lookup(ClassTemplate->getDeclName());
898  if (Found.first == Found.second)
899    return 0;
900
901  ClassTemplateDecl *InstClassTemplate
902    = dyn_cast<ClassTemplateDecl>(*Found.first);
903  if (!InstClassTemplate)
904    return 0;
905
906  if (ClassTemplatePartialSpecializationDecl *Result
907        = InstClassTemplate->findPartialSpecInstantiatedFromMember(D))
908    return Result;
909
910  return InstantiateClassTemplatePartialSpecialization(InstClassTemplate, D);
911}
912
913Decl *
914TemplateDeclInstantiator::VisitFunctionTemplateDecl(FunctionTemplateDecl *D) {
915  // Create a local instantiation scope for this function template, which
916  // will contain the instantiations of the template parameters and then get
917  // merged with the local instantiation scope for the function template
918  // itself.
919  LocalInstantiationScope Scope(SemaRef);
920
921  TemplateParameterList *TempParams = D->getTemplateParameters();
922  TemplateParameterList *InstParams = SubstTemplateParams(TempParams);
923  if (!InstParams)
924    return NULL;
925
926  FunctionDecl *Instantiated = 0;
927  if (CXXMethodDecl *DMethod = dyn_cast<CXXMethodDecl>(D->getTemplatedDecl()))
928    Instantiated = cast_or_null<FunctionDecl>(VisitCXXMethodDecl(DMethod,
929                                                                 InstParams));
930  else
931    Instantiated = cast_or_null<FunctionDecl>(VisitFunctionDecl(
932                                                          D->getTemplatedDecl(),
933                                                                InstParams));
934
935  if (!Instantiated)
936    return 0;
937
938  Instantiated->setAccess(D->getAccess());
939
940  // Link the instantiated function template declaration to the function
941  // template from which it was instantiated.
942  FunctionTemplateDecl *InstTemplate
943    = Instantiated->getDescribedFunctionTemplate();
944  InstTemplate->setAccess(D->getAccess());
945  assert(InstTemplate &&
946         "VisitFunctionDecl/CXXMethodDecl didn't create a template!");
947
948  bool isFriend = (InstTemplate->getFriendObjectKind() != Decl::FOK_None);
949
950  // Link the instantiation back to the pattern *unless* this is a
951  // non-definition friend declaration.
952  if (!InstTemplate->getInstantiatedFromMemberTemplate() &&
953      !(isFriend && !D->getTemplatedDecl()->isThisDeclarationADefinition()))
954    InstTemplate->setInstantiatedFromMemberTemplate(D);
955
956  // Make declarations visible in the appropriate context.
957  if (!isFriend)
958    Owner->addDecl(InstTemplate);
959
960  return InstTemplate;
961}
962
963Decl *TemplateDeclInstantiator::VisitCXXRecordDecl(CXXRecordDecl *D) {
964  CXXRecordDecl *PrevDecl = 0;
965  if (D->isInjectedClassName())
966    PrevDecl = cast<CXXRecordDecl>(Owner);
967  else if (D->getPreviousDeclaration()) {
968    NamedDecl *Prev = SemaRef.FindInstantiatedDecl(D->getLocation(),
969                                                   D->getPreviousDeclaration(),
970                                                   TemplateArgs);
971    if (!Prev) return 0;
972    PrevDecl = cast<CXXRecordDecl>(Prev);
973  }
974
975  CXXRecordDecl *Record
976    = CXXRecordDecl::Create(SemaRef.Context, D->getTagKind(), Owner,
977                            D->getLocStart(), D->getLocation(),
978                            D->getIdentifier(), PrevDecl);
979
980  // Substitute the nested name specifier, if any.
981  if (SubstQualifier(D, Record))
982    return 0;
983
984  Record->setImplicit(D->isImplicit());
985  // FIXME: Check against AS_none is an ugly hack to work around the issue that
986  // the tag decls introduced by friend class declarations don't have an access
987  // specifier. Remove once this area of the code gets sorted out.
988  if (D->getAccess() != AS_none)
989    Record->setAccess(D->getAccess());
990  if (!D->isInjectedClassName())
991    Record->setInstantiationOfMemberClass(D, TSK_ImplicitInstantiation);
992
993  // If the original function was part of a friend declaration,
994  // inherit its namespace state.
995  if (Decl::FriendObjectKind FOK = D->getFriendObjectKind())
996    Record->setObjectOfFriendDecl(FOK == Decl::FOK_Declared);
997
998  // Make sure that anonymous structs and unions are recorded.
999  if (D->isAnonymousStructOrUnion()) {
1000    Record->setAnonymousStructOrUnion(true);
1001    if (Record->getDeclContext()->getRedeclContext()->isFunctionOrMethod())
1002      SemaRef.CurrentInstantiationScope->InstantiatedLocal(D, Record);
1003  }
1004
1005  Owner->addDecl(Record);
1006  return Record;
1007}
1008
1009/// Normal class members are of more specific types and therefore
1010/// don't make it here.  This function serves two purposes:
1011///   1) instantiating function templates
1012///   2) substituting friend declarations
1013/// FIXME: preserve function definitions in case #2
1014Decl *TemplateDeclInstantiator::VisitFunctionDecl(FunctionDecl *D,
1015                                       TemplateParameterList *TemplateParams) {
1016  // Check whether there is already a function template specialization for
1017  // this declaration.
1018  FunctionTemplateDecl *FunctionTemplate = D->getDescribedFunctionTemplate();
1019  void *InsertPos = 0;
1020  if (FunctionTemplate && !TemplateParams) {
1021    std::pair<const TemplateArgument *, unsigned> Innermost
1022      = TemplateArgs.getInnermost();
1023
1024    FunctionDecl *SpecFunc
1025      = FunctionTemplate->findSpecialization(Innermost.first, Innermost.second,
1026                                             InsertPos);
1027
1028    // If we already have a function template specialization, return it.
1029    if (SpecFunc)
1030      return SpecFunc;
1031  }
1032
1033  bool isFriend;
1034  if (FunctionTemplate)
1035    isFriend = (FunctionTemplate->getFriendObjectKind() != Decl::FOK_None);
1036  else
1037    isFriend = (D->getFriendObjectKind() != Decl::FOK_None);
1038
1039  bool MergeWithParentScope = (TemplateParams != 0) ||
1040    Owner->isFunctionOrMethod() ||
1041    !(isa<Decl>(Owner) &&
1042      cast<Decl>(Owner)->isDefinedOutsideFunctionOrMethod());
1043  LocalInstantiationScope Scope(SemaRef, MergeWithParentScope);
1044
1045  llvm::SmallVector<ParmVarDecl *, 4> Params;
1046  TypeSourceInfo *TInfo = D->getTypeSourceInfo();
1047  TInfo = SubstFunctionType(D, Params);
1048  if (!TInfo)
1049    return 0;
1050  QualType T = TInfo->getType();
1051
1052  NestedNameSpecifierLoc QualifierLoc = D->getQualifierLoc();
1053  if (QualifierLoc) {
1054    QualifierLoc = SemaRef.SubstNestedNameSpecifierLoc(QualifierLoc,
1055                                                       TemplateArgs);
1056    if (!QualifierLoc)
1057      return 0;
1058  }
1059
1060  // If we're instantiating a local function declaration, put the result
1061  // in the owner;  otherwise we need to find the instantiated context.
1062  DeclContext *DC;
1063  if (D->getDeclContext()->isFunctionOrMethod())
1064    DC = Owner;
1065  else if (isFriend && QualifierLoc) {
1066    CXXScopeSpec SS;
1067    SS.Adopt(QualifierLoc);
1068    DC = SemaRef.computeDeclContext(SS);
1069    if (!DC) return 0;
1070  } else {
1071    DC = SemaRef.FindInstantiatedContext(D->getLocation(), D->getDeclContext(),
1072                                         TemplateArgs);
1073  }
1074
1075  FunctionDecl *Function =
1076      FunctionDecl::Create(SemaRef.Context, DC, D->getInnerLocStart(),
1077                           D->getLocation(), D->getDeclName(), T, TInfo,
1078                           D->getStorageClass(), D->getStorageClassAsWritten(),
1079                           D->isInlineSpecified(), D->hasWrittenPrototype());
1080
1081  if (QualifierLoc)
1082    Function->setQualifierInfo(QualifierLoc);
1083
1084  DeclContext *LexicalDC = Owner;
1085  if (!isFriend && D->isOutOfLine()) {
1086    assert(D->getDeclContext()->isFileContext());
1087    LexicalDC = D->getDeclContext();
1088  }
1089
1090  Function->setLexicalDeclContext(LexicalDC);
1091
1092  // Attach the parameters
1093  if (isa<FunctionProtoType>(Function->getType())) {
1094    // Adopt the already-instantiated parameters into our own context.
1095    for (unsigned P = 0; P < Params.size(); ++P)
1096      if (Params[P])
1097        Params[P]->setOwningFunction(Function);
1098  } else {
1099    // Since we were instantiated via a typedef of a function type, create
1100    // new parameters.
1101    const FunctionProtoType *Proto
1102      = Function->getType()->getAs<FunctionProtoType>();
1103    assert(Proto && "No function prototype in template instantiation?");
1104    for (FunctionProtoType::arg_type_iterator AI = Proto->arg_type_begin(),
1105         AE = Proto->arg_type_end(); AI != AE; ++AI) {
1106      ParmVarDecl *Param
1107        = SemaRef.BuildParmVarDeclForTypedef(Function, Function->getLocation(),
1108                                             *AI);
1109      Param->setScopeInfo(0, Params.size());
1110      Params.push_back(Param);
1111    }
1112  }
1113  Function->setParams(Params.data(), Params.size());
1114
1115  SourceLocation InstantiateAtPOI;
1116  if (TemplateParams) {
1117    // Our resulting instantiation is actually a function template, since we
1118    // are substituting only the outer template parameters. For example, given
1119    //
1120    //   template<typename T>
1121    //   struct X {
1122    //     template<typename U> friend void f(T, U);
1123    //   };
1124    //
1125    //   X<int> x;
1126    //
1127    // We are instantiating the friend function template "f" within X<int>,
1128    // which means substituting int for T, but leaving "f" as a friend function
1129    // template.
1130    // Build the function template itself.
1131    FunctionTemplate = FunctionTemplateDecl::Create(SemaRef.Context, DC,
1132                                                    Function->getLocation(),
1133                                                    Function->getDeclName(),
1134                                                    TemplateParams, Function);
1135    Function->setDescribedFunctionTemplate(FunctionTemplate);
1136
1137    FunctionTemplate->setLexicalDeclContext(LexicalDC);
1138
1139    if (isFriend && D->isThisDeclarationADefinition()) {
1140      // TODO: should we remember this connection regardless of whether
1141      // the friend declaration provided a body?
1142      FunctionTemplate->setInstantiatedFromMemberTemplate(
1143                                           D->getDescribedFunctionTemplate());
1144    }
1145  } else if (FunctionTemplate) {
1146    // Record this function template specialization.
1147    std::pair<const TemplateArgument *, unsigned> Innermost
1148      = TemplateArgs.getInnermost();
1149    Function->setFunctionTemplateSpecialization(FunctionTemplate,
1150                            TemplateArgumentList::CreateCopy(SemaRef.Context,
1151                                                             Innermost.first,
1152                                                             Innermost.second),
1153                                                InsertPos);
1154  } else if (isFriend && D->isThisDeclarationADefinition()) {
1155    // TODO: should we remember this connection regardless of whether
1156    // the friend declaration provided a body?
1157    Function->setInstantiationOfMemberFunction(D, TSK_ImplicitInstantiation);
1158  }
1159
1160  if (InitFunctionInstantiation(Function, D))
1161    Function->setInvalidDecl();
1162
1163  bool Redeclaration = false;
1164  bool isExplicitSpecialization = false;
1165
1166  LookupResult Previous(SemaRef, Function->getDeclName(), SourceLocation(),
1167                        Sema::LookupOrdinaryName, Sema::ForRedeclaration);
1168
1169  if (DependentFunctionTemplateSpecializationInfo *Info
1170        = D->getDependentSpecializationInfo()) {
1171    assert(isFriend && "non-friend has dependent specialization info?");
1172
1173    // This needs to be set now for future sanity.
1174    Function->setObjectOfFriendDecl(/*HasPrevious*/ true);
1175
1176    // Instantiate the explicit template arguments.
1177    TemplateArgumentListInfo ExplicitArgs(Info->getLAngleLoc(),
1178                                          Info->getRAngleLoc());
1179    if (SemaRef.Subst(Info->getTemplateArgs(), Info->getNumTemplateArgs(),
1180                      ExplicitArgs, TemplateArgs))
1181      return 0;
1182
1183    // Map the candidate templates to their instantiations.
1184    for (unsigned I = 0, E = Info->getNumTemplates(); I != E; ++I) {
1185      Decl *Temp = SemaRef.FindInstantiatedDecl(D->getLocation(),
1186                                                Info->getTemplate(I),
1187                                                TemplateArgs);
1188      if (!Temp) return 0;
1189
1190      Previous.addDecl(cast<FunctionTemplateDecl>(Temp));
1191    }
1192
1193    if (SemaRef.CheckFunctionTemplateSpecialization(Function,
1194                                                    &ExplicitArgs,
1195                                                    Previous))
1196      Function->setInvalidDecl();
1197
1198    isExplicitSpecialization = true;
1199
1200  } else if (TemplateParams || !FunctionTemplate) {
1201    // Look only into the namespace where the friend would be declared to
1202    // find a previous declaration. This is the innermost enclosing namespace,
1203    // as described in ActOnFriendFunctionDecl.
1204    SemaRef.LookupQualifiedName(Previous, DC);
1205
1206    // In C++, the previous declaration we find might be a tag type
1207    // (class or enum). In this case, the new declaration will hide the
1208    // tag type. Note that this does does not apply if we're declaring a
1209    // typedef (C++ [dcl.typedef]p4).
1210    if (Previous.isSingleTagDecl())
1211      Previous.clear();
1212  }
1213
1214  SemaRef.CheckFunctionDeclaration(/*Scope*/ 0, Function, Previous,
1215                                   isExplicitSpecialization, Redeclaration);
1216
1217  NamedDecl *PrincipalDecl = (TemplateParams
1218                              ? cast<NamedDecl>(FunctionTemplate)
1219                              : Function);
1220
1221  // If the original function was part of a friend declaration,
1222  // inherit its namespace state and add it to the owner.
1223  if (isFriend) {
1224    NamedDecl *PrevDecl;
1225    if (TemplateParams)
1226      PrevDecl = FunctionTemplate->getPreviousDeclaration();
1227    else
1228      PrevDecl = Function->getPreviousDeclaration();
1229
1230    PrincipalDecl->setObjectOfFriendDecl(PrevDecl != 0);
1231    DC->makeDeclVisibleInContext(PrincipalDecl, /*Recoverable=*/ false);
1232
1233    bool queuedInstantiation = false;
1234
1235    if (!SemaRef.getLangOptions().CPlusPlus0x &&
1236        D->isThisDeclarationADefinition()) {
1237      // Check for a function body.
1238      const FunctionDecl *Definition = 0;
1239      if (Function->isDefined(Definition) &&
1240          Definition->getTemplateSpecializationKind() == TSK_Undeclared) {
1241        SemaRef.Diag(Function->getLocation(), diag::err_redefinition)
1242          << Function->getDeclName();
1243        SemaRef.Diag(Definition->getLocation(), diag::note_previous_definition);
1244        Function->setInvalidDecl();
1245      }
1246      // Check for redefinitions due to other instantiations of this or
1247      // a similar friend function.
1248      else for (FunctionDecl::redecl_iterator R = Function->redecls_begin(),
1249                                           REnd = Function->redecls_end();
1250                R != REnd; ++R) {
1251        if (*R == Function)
1252          continue;
1253        switch (R->getFriendObjectKind()) {
1254        case Decl::FOK_None:
1255          if (!queuedInstantiation && R->isUsed(false)) {
1256            if (MemberSpecializationInfo *MSInfo
1257                = Function->getMemberSpecializationInfo()) {
1258              if (MSInfo->getPointOfInstantiation().isInvalid()) {
1259                SourceLocation Loc = R->getLocation(); // FIXME
1260                MSInfo->setPointOfInstantiation(Loc);
1261                SemaRef.PendingLocalImplicitInstantiations.push_back(
1262                                                 std::make_pair(Function, Loc));
1263                queuedInstantiation = true;
1264              }
1265            }
1266          }
1267          break;
1268        default:
1269          if (const FunctionDecl *RPattern
1270              = R->getTemplateInstantiationPattern())
1271            if (RPattern->isDefined(RPattern)) {
1272              SemaRef.Diag(Function->getLocation(), diag::err_redefinition)
1273                << Function->getDeclName();
1274              SemaRef.Diag(R->getLocation(), diag::note_previous_definition);
1275              Function->setInvalidDecl();
1276              break;
1277            }
1278        }
1279      }
1280    }
1281  }
1282
1283  if (Function->isOverloadedOperator() && !DC->isRecord() &&
1284      PrincipalDecl->isInIdentifierNamespace(Decl::IDNS_Ordinary))
1285    PrincipalDecl->setNonMemberOperator();
1286
1287  assert(!D->isDefaulted() && "only methods should be defaulted");
1288  return Function;
1289}
1290
1291Decl *
1292TemplateDeclInstantiator::VisitCXXMethodDecl(CXXMethodDecl *D,
1293                                      TemplateParameterList *TemplateParams) {
1294  FunctionTemplateDecl *FunctionTemplate = D->getDescribedFunctionTemplate();
1295  void *InsertPos = 0;
1296  if (FunctionTemplate && !TemplateParams) {
1297    // We are creating a function template specialization from a function
1298    // template. Check whether there is already a function template
1299    // specialization for this particular set of template arguments.
1300    std::pair<const TemplateArgument *, unsigned> Innermost
1301      = TemplateArgs.getInnermost();
1302
1303    FunctionDecl *SpecFunc
1304      = FunctionTemplate->findSpecialization(Innermost.first, Innermost.second,
1305                                             InsertPos);
1306
1307    // If we already have a function template specialization, return it.
1308    if (SpecFunc)
1309      return SpecFunc;
1310  }
1311
1312  bool isFriend;
1313  if (FunctionTemplate)
1314    isFriend = (FunctionTemplate->getFriendObjectKind() != Decl::FOK_None);
1315  else
1316    isFriend = (D->getFriendObjectKind() != Decl::FOK_None);
1317
1318  bool MergeWithParentScope = (TemplateParams != 0) ||
1319    !(isa<Decl>(Owner) &&
1320      cast<Decl>(Owner)->isDefinedOutsideFunctionOrMethod());
1321  LocalInstantiationScope Scope(SemaRef, MergeWithParentScope);
1322
1323  // Instantiate enclosing template arguments for friends.
1324  llvm::SmallVector<TemplateParameterList *, 4> TempParamLists;
1325  unsigned NumTempParamLists = 0;
1326  if (isFriend && (NumTempParamLists = D->getNumTemplateParameterLists())) {
1327    TempParamLists.set_size(NumTempParamLists);
1328    for (unsigned I = 0; I != NumTempParamLists; ++I) {
1329      TemplateParameterList *TempParams = D->getTemplateParameterList(I);
1330      TemplateParameterList *InstParams = SubstTemplateParams(TempParams);
1331      if (!InstParams)
1332        return NULL;
1333      TempParamLists[I] = InstParams;
1334    }
1335  }
1336
1337  llvm::SmallVector<ParmVarDecl *, 4> Params;
1338  TypeSourceInfo *TInfo = D->getTypeSourceInfo();
1339  TInfo = SubstFunctionType(D, Params);
1340  if (!TInfo)
1341    return 0;
1342  QualType T = TInfo->getType();
1343
1344  // \brief If the type of this function, after ignoring parentheses,
1345  // is not *directly* a function type, then we're instantiating a function
1346  // that was declared via a typedef, e.g.,
1347  //
1348  //   typedef int functype(int, int);
1349  //   functype func;
1350  //
1351  // In this case, we'll just go instantiate the ParmVarDecls that we
1352  // synthesized in the method declaration.
1353  if (!isa<FunctionProtoType>(T.IgnoreParens())) {
1354    assert(!Params.size() && "Instantiating type could not yield parameters");
1355    llvm::SmallVector<QualType, 4> ParamTypes;
1356    if (SemaRef.SubstParmTypes(D->getLocation(), D->param_begin(),
1357                               D->getNumParams(), TemplateArgs, ParamTypes,
1358                               &Params))
1359      return 0;
1360  }
1361
1362  NestedNameSpecifierLoc QualifierLoc = D->getQualifierLoc();
1363  if (QualifierLoc) {
1364    QualifierLoc = SemaRef.SubstNestedNameSpecifierLoc(QualifierLoc,
1365                                                 TemplateArgs);
1366    if (!QualifierLoc)
1367      return 0;
1368  }
1369
1370  DeclContext *DC = Owner;
1371  if (isFriend) {
1372    if (QualifierLoc) {
1373      CXXScopeSpec SS;
1374      SS.Adopt(QualifierLoc);
1375      DC = SemaRef.computeDeclContext(SS);
1376
1377      if (DC && SemaRef.RequireCompleteDeclContext(SS, DC))
1378        return 0;
1379    } else {
1380      DC = SemaRef.FindInstantiatedContext(D->getLocation(),
1381                                           D->getDeclContext(),
1382                                           TemplateArgs);
1383    }
1384    if (!DC) return 0;
1385  }
1386
1387  // Build the instantiated method declaration.
1388  CXXRecordDecl *Record = cast<CXXRecordDecl>(DC);
1389  CXXMethodDecl *Method = 0;
1390
1391  SourceLocation StartLoc = D->getInnerLocStart();
1392  DeclarationNameInfo NameInfo
1393    = SemaRef.SubstDeclarationNameInfo(D->getNameInfo(), TemplateArgs);
1394  if (CXXConstructorDecl *Constructor = dyn_cast<CXXConstructorDecl>(D)) {
1395    Method = CXXConstructorDecl::Create(SemaRef.Context, Record,
1396                                        StartLoc, NameInfo, T, TInfo,
1397                                        Constructor->isExplicit(),
1398                                        Constructor->isInlineSpecified(),
1399                                        false);
1400  } else if (CXXDestructorDecl *Destructor = dyn_cast<CXXDestructorDecl>(D)) {
1401    Method = CXXDestructorDecl::Create(SemaRef.Context, Record,
1402                                       StartLoc, NameInfo, T, TInfo,
1403                                       Destructor->isInlineSpecified(),
1404                                       false);
1405  } else if (CXXConversionDecl *Conversion = dyn_cast<CXXConversionDecl>(D)) {
1406    Method = CXXConversionDecl::Create(SemaRef.Context, Record,
1407                                       StartLoc, NameInfo, T, TInfo,
1408                                       Conversion->isInlineSpecified(),
1409                                       Conversion->isExplicit(),
1410                                       Conversion->getLocEnd());
1411  } else {
1412    Method = CXXMethodDecl::Create(SemaRef.Context, Record,
1413                                   StartLoc, NameInfo, T, TInfo,
1414                                   D->isStatic(),
1415                                   D->getStorageClassAsWritten(),
1416                                   D->isInlineSpecified(),
1417                                   D->getLocEnd());
1418  }
1419
1420  if (QualifierLoc)
1421    Method->setQualifierInfo(QualifierLoc);
1422
1423  if (TemplateParams) {
1424    // Our resulting instantiation is actually a function template, since we
1425    // are substituting only the outer template parameters. For example, given
1426    //
1427    //   template<typename T>
1428    //   struct X {
1429    //     template<typename U> void f(T, U);
1430    //   };
1431    //
1432    //   X<int> x;
1433    //
1434    // We are instantiating the member template "f" within X<int>, which means
1435    // substituting int for T, but leaving "f" as a member function template.
1436    // Build the function template itself.
1437    FunctionTemplate = FunctionTemplateDecl::Create(SemaRef.Context, Record,
1438                                                    Method->getLocation(),
1439                                                    Method->getDeclName(),
1440                                                    TemplateParams, Method);
1441    if (isFriend) {
1442      FunctionTemplate->setLexicalDeclContext(Owner);
1443      FunctionTemplate->setObjectOfFriendDecl(true);
1444    } else if (D->isOutOfLine())
1445      FunctionTemplate->setLexicalDeclContext(D->getLexicalDeclContext());
1446    Method->setDescribedFunctionTemplate(FunctionTemplate);
1447  } else if (FunctionTemplate) {
1448    // Record this function template specialization.
1449    std::pair<const TemplateArgument *, unsigned> Innermost
1450      = TemplateArgs.getInnermost();
1451    Method->setFunctionTemplateSpecialization(FunctionTemplate,
1452                         TemplateArgumentList::CreateCopy(SemaRef.Context,
1453                                                          Innermost.first,
1454                                                          Innermost.second),
1455                                              InsertPos);
1456  } else if (!isFriend) {
1457    // Record that this is an instantiation of a member function.
1458    Method->setInstantiationOfMemberFunction(D, TSK_ImplicitInstantiation);
1459  }
1460
1461  // If we are instantiating a member function defined
1462  // out-of-line, the instantiation will have the same lexical
1463  // context (which will be a namespace scope) as the template.
1464  if (isFriend) {
1465    if (NumTempParamLists)
1466      Method->setTemplateParameterListsInfo(SemaRef.Context,
1467                                            NumTempParamLists,
1468                                            TempParamLists.data());
1469
1470    Method->setLexicalDeclContext(Owner);
1471    Method->setObjectOfFriendDecl(true);
1472  } else if (D->isOutOfLine())
1473    Method->setLexicalDeclContext(D->getLexicalDeclContext());
1474
1475  // Attach the parameters
1476  for (unsigned P = 0; P < Params.size(); ++P)
1477    Params[P]->setOwningFunction(Method);
1478  Method->setParams(Params.data(), Params.size());
1479
1480  if (InitMethodInstantiation(Method, D))
1481    Method->setInvalidDecl();
1482
1483  LookupResult Previous(SemaRef, NameInfo, Sema::LookupOrdinaryName,
1484                        Sema::ForRedeclaration);
1485
1486  if (!FunctionTemplate || TemplateParams || isFriend) {
1487    SemaRef.LookupQualifiedName(Previous, Record);
1488
1489    // In C++, the previous declaration we find might be a tag type
1490    // (class or enum). In this case, the new declaration will hide the
1491    // tag type. Note that this does does not apply if we're declaring a
1492    // typedef (C++ [dcl.typedef]p4).
1493    if (Previous.isSingleTagDecl())
1494      Previous.clear();
1495  }
1496
1497  bool Redeclaration = false;
1498  SemaRef.CheckFunctionDeclaration(0, Method, Previous, false, Redeclaration);
1499
1500  if (D->isPure())
1501    SemaRef.CheckPureMethod(Method, SourceRange());
1502
1503  Method->setAccess(D->getAccess());
1504
1505  SemaRef.CheckOverrideControl(Method);
1506
1507  if (FunctionTemplate) {
1508    // If there's a function template, let our caller handle it.
1509  } else if (Method->isInvalidDecl() && !Previous.empty()) {
1510    // Don't hide a (potentially) valid declaration with an invalid one.
1511  } else {
1512    NamedDecl *DeclToAdd = (TemplateParams
1513                            ? cast<NamedDecl>(FunctionTemplate)
1514                            : Method);
1515    if (isFriend)
1516      Record->makeDeclVisibleInContext(DeclToAdd);
1517    else
1518      Owner->addDecl(DeclToAdd);
1519  }
1520
1521  if (D->isExplicitlyDefaulted()) {
1522    SemaRef.SetDeclDefaulted(Method, Method->getLocation());
1523  } else {
1524    assert(!D->isDefaulted() &&
1525           "should not implicitly default uninstantiated function");
1526  }
1527
1528  return Method;
1529}
1530
1531Decl *TemplateDeclInstantiator::VisitCXXConstructorDecl(CXXConstructorDecl *D) {
1532  return VisitCXXMethodDecl(D);
1533}
1534
1535Decl *TemplateDeclInstantiator::VisitCXXDestructorDecl(CXXDestructorDecl *D) {
1536  return VisitCXXMethodDecl(D);
1537}
1538
1539Decl *TemplateDeclInstantiator::VisitCXXConversionDecl(CXXConversionDecl *D) {
1540  return VisitCXXMethodDecl(D);
1541}
1542
1543ParmVarDecl *TemplateDeclInstantiator::VisitParmVarDecl(ParmVarDecl *D) {
1544  return SemaRef.SubstParmVarDecl(D, TemplateArgs, /*indexAdjustment*/ 0,
1545                                  llvm::Optional<unsigned>());
1546}
1547
1548Decl *TemplateDeclInstantiator::VisitTemplateTypeParmDecl(
1549                                                    TemplateTypeParmDecl *D) {
1550  // TODO: don't always clone when decls are refcounted.
1551  assert(D->getTypeForDecl()->isTemplateTypeParmType());
1552
1553  TemplateTypeParmDecl *Inst =
1554    TemplateTypeParmDecl::Create(SemaRef.Context, Owner,
1555                                 D->getLocStart(), D->getLocation(),
1556                                 D->getDepth() - TemplateArgs.getNumLevels(),
1557                                 D->getIndex(), D->getIdentifier(),
1558                                 D->wasDeclaredWithTypename(),
1559                                 D->isParameterPack());
1560  Inst->setAccess(AS_public);
1561
1562  if (D->hasDefaultArgument())
1563    Inst->setDefaultArgument(D->getDefaultArgumentInfo(), false);
1564
1565  // Introduce this template parameter's instantiation into the instantiation
1566  // scope.
1567  SemaRef.CurrentInstantiationScope->InstantiatedLocal(D, Inst);
1568
1569  return Inst;
1570}
1571
1572Decl *TemplateDeclInstantiator::VisitNonTypeTemplateParmDecl(
1573                                                 NonTypeTemplateParmDecl *D) {
1574  // Substitute into the type of the non-type template parameter.
1575  TypeLoc TL = D->getTypeSourceInfo()->getTypeLoc();
1576  llvm::SmallVector<TypeSourceInfo *, 4> ExpandedParameterPackTypesAsWritten;
1577  llvm::SmallVector<QualType, 4> ExpandedParameterPackTypes;
1578  bool IsExpandedParameterPack = false;
1579  TypeSourceInfo *DI;
1580  QualType T;
1581  bool Invalid = false;
1582
1583  if (D->isExpandedParameterPack()) {
1584    // The non-type template parameter pack is an already-expanded pack
1585    // expansion of types. Substitute into each of the expanded types.
1586    ExpandedParameterPackTypes.reserve(D->getNumExpansionTypes());
1587    ExpandedParameterPackTypesAsWritten.reserve(D->getNumExpansionTypes());
1588    for (unsigned I = 0, N = D->getNumExpansionTypes(); I != N; ++I) {
1589      TypeSourceInfo *NewDI =SemaRef.SubstType(D->getExpansionTypeSourceInfo(I),
1590                                               TemplateArgs,
1591                                               D->getLocation(),
1592                                               D->getDeclName());
1593      if (!NewDI)
1594        return 0;
1595
1596      ExpandedParameterPackTypesAsWritten.push_back(NewDI);
1597      QualType NewT =SemaRef.CheckNonTypeTemplateParameterType(NewDI->getType(),
1598                                                              D->getLocation());
1599      if (NewT.isNull())
1600        return 0;
1601      ExpandedParameterPackTypes.push_back(NewT);
1602    }
1603
1604    IsExpandedParameterPack = true;
1605    DI = D->getTypeSourceInfo();
1606    T = DI->getType();
1607  } else if (isa<PackExpansionTypeLoc>(TL)) {
1608    // The non-type template parameter pack's type is a pack expansion of types.
1609    // Determine whether we need to expand this parameter pack into separate
1610    // types.
1611    PackExpansionTypeLoc Expansion = cast<PackExpansionTypeLoc>(TL);
1612    TypeLoc Pattern = Expansion.getPatternLoc();
1613    llvm::SmallVector<UnexpandedParameterPack, 2> Unexpanded;
1614    SemaRef.collectUnexpandedParameterPacks(Pattern, Unexpanded);
1615
1616    // Determine whether the set of unexpanded parameter packs can and should
1617    // be expanded.
1618    bool Expand = true;
1619    bool RetainExpansion = false;
1620    llvm::Optional<unsigned> OrigNumExpansions
1621      = Expansion.getTypePtr()->getNumExpansions();
1622    llvm::Optional<unsigned> NumExpansions = OrigNumExpansions;
1623    if (SemaRef.CheckParameterPacksForExpansion(Expansion.getEllipsisLoc(),
1624                                                Pattern.getSourceRange(),
1625                                                Unexpanded.data(),
1626                                                Unexpanded.size(),
1627                                                TemplateArgs,
1628                                                Expand, RetainExpansion,
1629                                                NumExpansions))
1630      return 0;
1631
1632    if (Expand) {
1633      for (unsigned I = 0; I != *NumExpansions; ++I) {
1634        Sema::ArgumentPackSubstitutionIndexRAII SubstIndex(SemaRef, I);
1635        TypeSourceInfo *NewDI = SemaRef.SubstType(Pattern, TemplateArgs,
1636                                                  D->getLocation(),
1637                                                  D->getDeclName());
1638        if (!NewDI)
1639          return 0;
1640
1641        ExpandedParameterPackTypesAsWritten.push_back(NewDI);
1642        QualType NewT = SemaRef.CheckNonTypeTemplateParameterType(
1643                                                              NewDI->getType(),
1644                                                              D->getLocation());
1645        if (NewT.isNull())
1646          return 0;
1647        ExpandedParameterPackTypes.push_back(NewT);
1648      }
1649
1650      // Note that we have an expanded parameter pack. The "type" of this
1651      // expanded parameter pack is the original expansion type, but callers
1652      // will end up using the expanded parameter pack types for type-checking.
1653      IsExpandedParameterPack = true;
1654      DI = D->getTypeSourceInfo();
1655      T = DI->getType();
1656    } else {
1657      // We cannot fully expand the pack expansion now, so substitute into the
1658      // pattern and create a new pack expansion type.
1659      Sema::ArgumentPackSubstitutionIndexRAII SubstIndex(SemaRef, -1);
1660      TypeSourceInfo *NewPattern = SemaRef.SubstType(Pattern, TemplateArgs,
1661                                                     D->getLocation(),
1662                                                     D->getDeclName());
1663      if (!NewPattern)
1664        return 0;
1665
1666      DI = SemaRef.CheckPackExpansion(NewPattern, Expansion.getEllipsisLoc(),
1667                                      NumExpansions);
1668      if (!DI)
1669        return 0;
1670
1671      T = DI->getType();
1672    }
1673  } else {
1674    // Simple case: substitution into a parameter that is not a parameter pack.
1675    DI = SemaRef.SubstType(D->getTypeSourceInfo(), TemplateArgs,
1676                           D->getLocation(), D->getDeclName());
1677    if (!DI)
1678      return 0;
1679
1680    // Check that this type is acceptable for a non-type template parameter.
1681    T = SemaRef.CheckNonTypeTemplateParameterType(DI->getType(),
1682                                                  D->getLocation());
1683    if (T.isNull()) {
1684      T = SemaRef.Context.IntTy;
1685      Invalid = true;
1686    }
1687  }
1688
1689  NonTypeTemplateParmDecl *Param;
1690  if (IsExpandedParameterPack)
1691    Param = NonTypeTemplateParmDecl::Create(SemaRef.Context, Owner,
1692                                            D->getInnerLocStart(),
1693                                            D->getLocation(),
1694                                    D->getDepth() - TemplateArgs.getNumLevels(),
1695                                            D->getPosition(),
1696                                            D->getIdentifier(), T,
1697                                            DI,
1698                                            ExpandedParameterPackTypes.data(),
1699                                            ExpandedParameterPackTypes.size(),
1700                                    ExpandedParameterPackTypesAsWritten.data());
1701  else
1702    Param = NonTypeTemplateParmDecl::Create(SemaRef.Context, Owner,
1703                                            D->getInnerLocStart(),
1704                                            D->getLocation(),
1705                                    D->getDepth() - TemplateArgs.getNumLevels(),
1706                                            D->getPosition(),
1707                                            D->getIdentifier(), T,
1708                                            D->isParameterPack(), DI);
1709
1710  Param->setAccess(AS_public);
1711  if (Invalid)
1712    Param->setInvalidDecl();
1713
1714  Param->setDefaultArgument(D->getDefaultArgument(), false);
1715
1716  // Introduce this template parameter's instantiation into the instantiation
1717  // scope.
1718  SemaRef.CurrentInstantiationScope->InstantiatedLocal(D, Param);
1719  return Param;
1720}
1721
1722Decl *
1723TemplateDeclInstantiator::VisitTemplateTemplateParmDecl(
1724                                                  TemplateTemplateParmDecl *D) {
1725  // Instantiate the template parameter list of the template template parameter.
1726  TemplateParameterList *TempParams = D->getTemplateParameters();
1727  TemplateParameterList *InstParams;
1728  {
1729    // Perform the actual substitution of template parameters within a new,
1730    // local instantiation scope.
1731    LocalInstantiationScope Scope(SemaRef);
1732    InstParams = SubstTemplateParams(TempParams);
1733    if (!InstParams)
1734      return NULL;
1735  }
1736
1737  // Build the template template parameter.
1738  TemplateTemplateParmDecl *Param
1739    = TemplateTemplateParmDecl::Create(SemaRef.Context, Owner, D->getLocation(),
1740                                   D->getDepth() - TemplateArgs.getNumLevels(),
1741                                       D->getPosition(), D->isParameterPack(),
1742                                       D->getIdentifier(), InstParams);
1743  Param->setDefaultArgument(D->getDefaultArgument(), false);
1744  Param->setAccess(AS_public);
1745
1746  // Introduce this template parameter's instantiation into the instantiation
1747  // scope.
1748  SemaRef.CurrentInstantiationScope->InstantiatedLocal(D, Param);
1749
1750  return Param;
1751}
1752
1753Decl *TemplateDeclInstantiator::VisitUsingDirectiveDecl(UsingDirectiveDecl *D) {
1754  // Using directives are never dependent (and never contain any types or
1755  // expressions), so they require no explicit instantiation work.
1756
1757  UsingDirectiveDecl *Inst
1758    = UsingDirectiveDecl::Create(SemaRef.Context, Owner, D->getLocation(),
1759                                 D->getNamespaceKeyLocation(),
1760                                 D->getQualifierLoc(),
1761                                 D->getIdentLocation(),
1762                                 D->getNominatedNamespace(),
1763                                 D->getCommonAncestor());
1764  Owner->addDecl(Inst);
1765  return Inst;
1766}
1767
1768Decl *TemplateDeclInstantiator::VisitUsingDecl(UsingDecl *D) {
1769
1770  // The nested name specifier may be dependent, for example
1771  //     template <typename T> struct t {
1772  //       struct s1 { T f1(); };
1773  //       struct s2 : s1 { using s1::f1; };
1774  //     };
1775  //     template struct t<int>;
1776  // Here, in using s1::f1, s1 refers to t<T>::s1;
1777  // we need to substitute for t<int>::s1.
1778  NestedNameSpecifierLoc QualifierLoc
1779    = SemaRef.SubstNestedNameSpecifierLoc(D->getQualifierLoc(),
1780                                          TemplateArgs);
1781  if (!QualifierLoc)
1782    return 0;
1783
1784  // The name info is non-dependent, so no transformation
1785  // is required.
1786  DeclarationNameInfo NameInfo = D->getNameInfo();
1787
1788  // We only need to do redeclaration lookups if we're in a class
1789  // scope (in fact, it's not really even possible in non-class
1790  // scopes).
1791  bool CheckRedeclaration = Owner->isRecord();
1792
1793  LookupResult Prev(SemaRef, NameInfo, Sema::LookupUsingDeclName,
1794                    Sema::ForRedeclaration);
1795
1796  UsingDecl *NewUD = UsingDecl::Create(SemaRef.Context, Owner,
1797                                       D->getUsingLocation(),
1798                                       QualifierLoc,
1799                                       NameInfo,
1800                                       D->isTypeName());
1801
1802  CXXScopeSpec SS;
1803  SS.Adopt(QualifierLoc);
1804  if (CheckRedeclaration) {
1805    Prev.setHideTags(false);
1806    SemaRef.LookupQualifiedName(Prev, Owner);
1807
1808    // Check for invalid redeclarations.
1809    if (SemaRef.CheckUsingDeclRedeclaration(D->getUsingLocation(),
1810                                            D->isTypeName(), SS,
1811                                            D->getLocation(), Prev))
1812      NewUD->setInvalidDecl();
1813
1814  }
1815
1816  if (!NewUD->isInvalidDecl() &&
1817      SemaRef.CheckUsingDeclQualifier(D->getUsingLocation(), SS,
1818                                      D->getLocation()))
1819    NewUD->setInvalidDecl();
1820
1821  SemaRef.Context.setInstantiatedFromUsingDecl(NewUD, D);
1822  NewUD->setAccess(D->getAccess());
1823  Owner->addDecl(NewUD);
1824
1825  // Don't process the shadow decls for an invalid decl.
1826  if (NewUD->isInvalidDecl())
1827    return NewUD;
1828
1829  bool isFunctionScope = Owner->isFunctionOrMethod();
1830
1831  // Process the shadow decls.
1832  for (UsingDecl::shadow_iterator I = D->shadow_begin(), E = D->shadow_end();
1833         I != E; ++I) {
1834    UsingShadowDecl *Shadow = *I;
1835    NamedDecl *InstTarget =
1836      cast_or_null<NamedDecl>(SemaRef.FindInstantiatedDecl(
1837                                                          Shadow->getLocation(),
1838                                                        Shadow->getTargetDecl(),
1839                                                           TemplateArgs));
1840    if (!InstTarget)
1841      return 0;
1842
1843    if (CheckRedeclaration &&
1844        SemaRef.CheckUsingShadowDecl(NewUD, InstTarget, Prev))
1845      continue;
1846
1847    UsingShadowDecl *InstShadow
1848      = SemaRef.BuildUsingShadowDecl(/*Scope*/ 0, NewUD, InstTarget);
1849    SemaRef.Context.setInstantiatedFromUsingShadowDecl(InstShadow, Shadow);
1850
1851    if (isFunctionScope)
1852      SemaRef.CurrentInstantiationScope->InstantiatedLocal(Shadow, InstShadow);
1853  }
1854
1855  return NewUD;
1856}
1857
1858Decl *TemplateDeclInstantiator::VisitUsingShadowDecl(UsingShadowDecl *D) {
1859  // Ignore these;  we handle them in bulk when processing the UsingDecl.
1860  return 0;
1861}
1862
1863Decl * TemplateDeclInstantiator
1864    ::VisitUnresolvedUsingTypenameDecl(UnresolvedUsingTypenameDecl *D) {
1865  NestedNameSpecifierLoc QualifierLoc
1866    = SemaRef.SubstNestedNameSpecifierLoc(D->getQualifierLoc(),
1867                                          TemplateArgs);
1868  if (!QualifierLoc)
1869    return 0;
1870
1871  CXXScopeSpec SS;
1872  SS.Adopt(QualifierLoc);
1873
1874  // Since NameInfo refers to a typename, it cannot be a C++ special name.
1875  // Hence, no tranformation is required for it.
1876  DeclarationNameInfo NameInfo(D->getDeclName(), D->getLocation());
1877  NamedDecl *UD =
1878    SemaRef.BuildUsingDeclaration(/*Scope*/ 0, D->getAccess(),
1879                                  D->getUsingLoc(), SS, NameInfo, 0,
1880                                  /*instantiation*/ true,
1881                                  /*typename*/ true, D->getTypenameLoc());
1882  if (UD)
1883    SemaRef.Context.setInstantiatedFromUsingDecl(cast<UsingDecl>(UD), D);
1884
1885  return UD;
1886}
1887
1888Decl * TemplateDeclInstantiator
1889    ::VisitUnresolvedUsingValueDecl(UnresolvedUsingValueDecl *D) {
1890  NestedNameSpecifierLoc QualifierLoc
1891      = SemaRef.SubstNestedNameSpecifierLoc(D->getQualifierLoc(), TemplateArgs);
1892  if (!QualifierLoc)
1893    return 0;
1894
1895  CXXScopeSpec SS;
1896  SS.Adopt(QualifierLoc);
1897
1898  DeclarationNameInfo NameInfo
1899    = SemaRef.SubstDeclarationNameInfo(D->getNameInfo(), TemplateArgs);
1900
1901  NamedDecl *UD =
1902    SemaRef.BuildUsingDeclaration(/*Scope*/ 0, D->getAccess(),
1903                                  D->getUsingLoc(), SS, NameInfo, 0,
1904                                  /*instantiation*/ true,
1905                                  /*typename*/ false, SourceLocation());
1906  if (UD)
1907    SemaRef.Context.setInstantiatedFromUsingDecl(cast<UsingDecl>(UD), D);
1908
1909  return UD;
1910}
1911
1912Decl *Sema::SubstDecl(Decl *D, DeclContext *Owner,
1913                      const MultiLevelTemplateArgumentList &TemplateArgs) {
1914  TemplateDeclInstantiator Instantiator(*this, Owner, TemplateArgs);
1915  if (D->isInvalidDecl())
1916    return 0;
1917
1918  return Instantiator.Visit(D);
1919}
1920
1921/// \brief Instantiates a nested template parameter list in the current
1922/// instantiation context.
1923///
1924/// \param L The parameter list to instantiate
1925///
1926/// \returns NULL if there was an error
1927TemplateParameterList *
1928TemplateDeclInstantiator::SubstTemplateParams(TemplateParameterList *L) {
1929  // Get errors for all the parameters before bailing out.
1930  bool Invalid = false;
1931
1932  unsigned N = L->size();
1933  typedef llvm::SmallVector<NamedDecl *, 8> ParamVector;
1934  ParamVector Params;
1935  Params.reserve(N);
1936  for (TemplateParameterList::iterator PI = L->begin(), PE = L->end();
1937       PI != PE; ++PI) {
1938    NamedDecl *D = cast_or_null<NamedDecl>(Visit(*PI));
1939    Params.push_back(D);
1940    Invalid = Invalid || !D || D->isInvalidDecl();
1941  }
1942
1943  // Clean up if we had an error.
1944  if (Invalid)
1945    return NULL;
1946
1947  TemplateParameterList *InstL
1948    = TemplateParameterList::Create(SemaRef.Context, L->getTemplateLoc(),
1949                                    L->getLAngleLoc(), &Params.front(), N,
1950                                    L->getRAngleLoc());
1951  return InstL;
1952}
1953
1954/// \brief Instantiate the declaration of a class template partial
1955/// specialization.
1956///
1957/// \param ClassTemplate the (instantiated) class template that is partially
1958// specialized by the instantiation of \p PartialSpec.
1959///
1960/// \param PartialSpec the (uninstantiated) class template partial
1961/// specialization that we are instantiating.
1962///
1963/// \returns The instantiated partial specialization, if successful; otherwise,
1964/// NULL to indicate an error.
1965ClassTemplatePartialSpecializationDecl *
1966TemplateDeclInstantiator::InstantiateClassTemplatePartialSpecialization(
1967                                            ClassTemplateDecl *ClassTemplate,
1968                          ClassTemplatePartialSpecializationDecl *PartialSpec) {
1969  // Create a local instantiation scope for this class template partial
1970  // specialization, which will contain the instantiations of the template
1971  // parameters.
1972  LocalInstantiationScope Scope(SemaRef);
1973
1974  // Substitute into the template parameters of the class template partial
1975  // specialization.
1976  TemplateParameterList *TempParams = PartialSpec->getTemplateParameters();
1977  TemplateParameterList *InstParams = SubstTemplateParams(TempParams);
1978  if (!InstParams)
1979    return 0;
1980
1981  // Substitute into the template arguments of the class template partial
1982  // specialization.
1983  TemplateArgumentListInfo InstTemplateArgs; // no angle locations
1984  if (SemaRef.Subst(PartialSpec->getTemplateArgsAsWritten(),
1985                    PartialSpec->getNumTemplateArgsAsWritten(),
1986                    InstTemplateArgs, TemplateArgs))
1987    return 0;
1988
1989  // Check that the template argument list is well-formed for this
1990  // class template.
1991  llvm::SmallVector<TemplateArgument, 4> Converted;
1992  if (SemaRef.CheckTemplateArgumentList(ClassTemplate,
1993                                        PartialSpec->getLocation(),
1994                                        InstTemplateArgs,
1995                                        false,
1996                                        Converted))
1997    return 0;
1998
1999  // Figure out where to insert this class template partial specialization
2000  // in the member template's set of class template partial specializations.
2001  void *InsertPos = 0;
2002  ClassTemplateSpecializationDecl *PrevDecl
2003    = ClassTemplate->findPartialSpecialization(Converted.data(),
2004                                               Converted.size(), InsertPos);
2005
2006  // Build the canonical type that describes the converted template
2007  // arguments of the class template partial specialization.
2008  QualType CanonType
2009    = SemaRef.Context.getTemplateSpecializationType(TemplateName(ClassTemplate),
2010                                                    Converted.data(),
2011                                                    Converted.size());
2012
2013  // Build the fully-sugared type for this class template
2014  // specialization as the user wrote in the specialization
2015  // itself. This means that we'll pretty-print the type retrieved
2016  // from the specialization's declaration the way that the user
2017  // actually wrote the specialization, rather than formatting the
2018  // name based on the "canonical" representation used to store the
2019  // template arguments in the specialization.
2020  TypeSourceInfo *WrittenTy
2021    = SemaRef.Context.getTemplateSpecializationTypeInfo(
2022                                                    TemplateName(ClassTemplate),
2023                                                    PartialSpec->getLocation(),
2024                                                    InstTemplateArgs,
2025                                                    CanonType);
2026
2027  if (PrevDecl) {
2028    // We've already seen a partial specialization with the same template
2029    // parameters and template arguments. This can happen, for example, when
2030    // substituting the outer template arguments ends up causing two
2031    // class template partial specializations of a member class template
2032    // to have identical forms, e.g.,
2033    //
2034    //   template<typename T, typename U>
2035    //   struct Outer {
2036    //     template<typename X, typename Y> struct Inner;
2037    //     template<typename Y> struct Inner<T, Y>;
2038    //     template<typename Y> struct Inner<U, Y>;
2039    //   };
2040    //
2041    //   Outer<int, int> outer; // error: the partial specializations of Inner
2042    //                          // have the same signature.
2043    SemaRef.Diag(PartialSpec->getLocation(), diag::err_partial_spec_redeclared)
2044      << WrittenTy->getType();
2045    SemaRef.Diag(PrevDecl->getLocation(), diag::note_prev_partial_spec_here)
2046      << SemaRef.Context.getTypeDeclType(PrevDecl);
2047    return 0;
2048  }
2049
2050
2051  // Create the class template partial specialization declaration.
2052  ClassTemplatePartialSpecializationDecl *InstPartialSpec
2053    = ClassTemplatePartialSpecializationDecl::Create(SemaRef.Context,
2054                                                     PartialSpec->getTagKind(),
2055                                                     Owner,
2056                                                     PartialSpec->getLocStart(),
2057                                                     PartialSpec->getLocation(),
2058                                                     InstParams,
2059                                                     ClassTemplate,
2060                                                     Converted.data(),
2061                                                     Converted.size(),
2062                                                     InstTemplateArgs,
2063                                                     CanonType,
2064                                                     0,
2065                             ClassTemplate->getNextPartialSpecSequenceNumber());
2066  // Substitute the nested name specifier, if any.
2067  if (SubstQualifier(PartialSpec, InstPartialSpec))
2068    return 0;
2069
2070  InstPartialSpec->setInstantiatedFromMember(PartialSpec);
2071  InstPartialSpec->setTypeAsWritten(WrittenTy);
2072
2073  // Add this partial specialization to the set of class template partial
2074  // specializations.
2075  ClassTemplate->AddPartialSpecialization(InstPartialSpec, InsertPos);
2076  return InstPartialSpec;
2077}
2078
2079TypeSourceInfo*
2080TemplateDeclInstantiator::SubstFunctionType(FunctionDecl *D,
2081                              llvm::SmallVectorImpl<ParmVarDecl *> &Params) {
2082  TypeSourceInfo *OldTInfo = D->getTypeSourceInfo();
2083  assert(OldTInfo && "substituting function without type source info");
2084  assert(Params.empty() && "parameter vector is non-empty at start");
2085  TypeSourceInfo *NewTInfo
2086    = SemaRef.SubstFunctionDeclType(OldTInfo, TemplateArgs,
2087                                    D->getTypeSpecStartLoc(),
2088                                    D->getDeclName());
2089  if (!NewTInfo)
2090    return 0;
2091
2092  if (NewTInfo != OldTInfo) {
2093    // Get parameters from the new type info.
2094    TypeLoc OldTL = OldTInfo->getTypeLoc().IgnoreParens();
2095    if (FunctionProtoTypeLoc *OldProtoLoc
2096                                  = dyn_cast<FunctionProtoTypeLoc>(&OldTL)) {
2097      TypeLoc NewTL = NewTInfo->getTypeLoc().IgnoreParens();
2098      FunctionProtoTypeLoc *NewProtoLoc = cast<FunctionProtoTypeLoc>(&NewTL);
2099      assert(NewProtoLoc && "Missing prototype?");
2100      unsigned NewIdx = 0, NumNewParams = NewProtoLoc->getNumArgs();
2101      for (unsigned OldIdx = 0, NumOldParams = OldProtoLoc->getNumArgs();
2102           OldIdx != NumOldParams; ++OldIdx) {
2103        ParmVarDecl *OldParam = OldProtoLoc->getArg(OldIdx);
2104        if (!OldParam->isParameterPack() ||
2105            (NewIdx < NumNewParams &&
2106             NewProtoLoc->getArg(NewIdx)->isParameterPack())) {
2107          // Simple case: normal parameter, or a parameter pack that's
2108          // instantiated to a (still-dependent) parameter pack.
2109          ParmVarDecl *NewParam = NewProtoLoc->getArg(NewIdx++);
2110          Params.push_back(NewParam);
2111          SemaRef.CurrentInstantiationScope->InstantiatedLocal(OldParam,
2112                                                               NewParam);
2113          continue;
2114        }
2115
2116        // Parameter pack: make the instantiation an argument pack.
2117        SemaRef.CurrentInstantiationScope->MakeInstantiatedLocalArgPack(
2118                                                                      OldParam);
2119        unsigned NumArgumentsInExpansion
2120          = SemaRef.getNumArgumentsInExpansion(OldParam->getType(),
2121                                               TemplateArgs);
2122        while (NumArgumentsInExpansion--) {
2123          ParmVarDecl *NewParam = NewProtoLoc->getArg(NewIdx++);
2124          Params.push_back(NewParam);
2125          SemaRef.CurrentInstantiationScope->InstantiatedLocalPackArg(OldParam,
2126                                                                      NewParam);
2127        }
2128      }
2129    }
2130  } else {
2131    // The function type itself was not dependent and therefore no
2132    // substitution occurred. However, we still need to instantiate
2133    // the function parameters themselves.
2134    TypeLoc OldTL = OldTInfo->getTypeLoc().IgnoreParens();
2135    if (FunctionProtoTypeLoc *OldProtoLoc
2136                                    = dyn_cast<FunctionProtoTypeLoc>(&OldTL)) {
2137      for (unsigned i = 0, i_end = OldProtoLoc->getNumArgs(); i != i_end; ++i) {
2138        ParmVarDecl *Parm = VisitParmVarDecl(OldProtoLoc->getArg(i));
2139        if (!Parm)
2140          return 0;
2141        Params.push_back(Parm);
2142      }
2143    }
2144  }
2145  return NewTInfo;
2146}
2147
2148/// \brief Initializes the common fields of an instantiation function
2149/// declaration (New) from the corresponding fields of its template (Tmpl).
2150///
2151/// \returns true if there was an error
2152bool
2153TemplateDeclInstantiator::InitFunctionInstantiation(FunctionDecl *New,
2154                                                    FunctionDecl *Tmpl) {
2155  if (Tmpl->isDeletedAsWritten())
2156    New->setDeletedAsWritten();
2157
2158  // If we are performing substituting explicitly-specified template arguments
2159  // or deduced template arguments into a function template and we reach this
2160  // point, we are now past the point where SFINAE applies and have committed
2161  // to keeping the new function template specialization. We therefore
2162  // convert the active template instantiation for the function template
2163  // into a template instantiation for this specific function template
2164  // specialization, which is not a SFINAE context, so that we diagnose any
2165  // further errors in the declaration itself.
2166  typedef Sema::ActiveTemplateInstantiation ActiveInstType;
2167  ActiveInstType &ActiveInst = SemaRef.ActiveTemplateInstantiations.back();
2168  if (ActiveInst.Kind == ActiveInstType::ExplicitTemplateArgumentSubstitution ||
2169      ActiveInst.Kind == ActiveInstType::DeducedTemplateArgumentSubstitution) {
2170    if (FunctionTemplateDecl *FunTmpl
2171          = dyn_cast<FunctionTemplateDecl>((Decl *)ActiveInst.Entity)) {
2172      assert(FunTmpl->getTemplatedDecl() == Tmpl &&
2173             "Deduction from the wrong function template?");
2174      (void) FunTmpl;
2175      ActiveInst.Kind = ActiveInstType::TemplateInstantiation;
2176      ActiveInst.Entity = reinterpret_cast<uintptr_t>(New);
2177      --SemaRef.NonInstantiationEntries;
2178    }
2179  }
2180
2181  const FunctionProtoType *Proto = Tmpl->getType()->getAs<FunctionProtoType>();
2182  assert(Proto && "Function template without prototype?");
2183
2184  if (Proto->hasExceptionSpec() || Proto->getNoReturnAttr()) {
2185    // The function has an exception specification or a "noreturn"
2186    // attribute. Substitute into each of the exception types.
2187    llvm::SmallVector<QualType, 4> Exceptions;
2188    for (unsigned I = 0, N = Proto->getNumExceptions(); I != N; ++I) {
2189      // FIXME: Poor location information!
2190      if (const PackExpansionType *PackExpansion
2191            = Proto->getExceptionType(I)->getAs<PackExpansionType>()) {
2192        // We have a pack expansion. Instantiate it.
2193        llvm::SmallVector<UnexpandedParameterPack, 2> Unexpanded;
2194        SemaRef.collectUnexpandedParameterPacks(PackExpansion->getPattern(),
2195                                                Unexpanded);
2196        assert(!Unexpanded.empty() &&
2197               "Pack expansion without parameter packs?");
2198
2199        bool Expand = false;
2200        bool RetainExpansion = false;
2201        llvm::Optional<unsigned> NumExpansions
2202                                          = PackExpansion->getNumExpansions();
2203        if (SemaRef.CheckParameterPacksForExpansion(New->getLocation(),
2204                                                    SourceRange(),
2205                                                    Unexpanded.data(),
2206                                                    Unexpanded.size(),
2207                                                    TemplateArgs,
2208                                                    Expand,
2209                                                    RetainExpansion,
2210                                                    NumExpansions))
2211          break;
2212
2213        if (!Expand) {
2214          // We can't expand this pack expansion into separate arguments yet;
2215          // just substitute into the pattern and create a new pack expansion
2216          // type.
2217          Sema::ArgumentPackSubstitutionIndexRAII SubstIndex(SemaRef, -1);
2218          QualType T = SemaRef.SubstType(PackExpansion->getPattern(),
2219                                         TemplateArgs,
2220                                       New->getLocation(), New->getDeclName());
2221          if (T.isNull())
2222            break;
2223
2224          T = SemaRef.Context.getPackExpansionType(T, NumExpansions);
2225          Exceptions.push_back(T);
2226          continue;
2227        }
2228
2229        // Substitute into the pack expansion pattern for each template
2230        bool Invalid = false;
2231        for (unsigned ArgIdx = 0; ArgIdx != *NumExpansions; ++ArgIdx) {
2232          Sema::ArgumentPackSubstitutionIndexRAII SubstIndex(SemaRef, ArgIdx);
2233
2234          QualType T = SemaRef.SubstType(PackExpansion->getPattern(),
2235                                         TemplateArgs,
2236                                       New->getLocation(), New->getDeclName());
2237          if (T.isNull()) {
2238            Invalid = true;
2239            break;
2240          }
2241
2242          Exceptions.push_back(T);
2243        }
2244
2245        if (Invalid)
2246          break;
2247
2248        continue;
2249      }
2250
2251      QualType T
2252        = SemaRef.SubstType(Proto->getExceptionType(I), TemplateArgs,
2253                            New->getLocation(), New->getDeclName());
2254      if (T.isNull() ||
2255          SemaRef.CheckSpecifiedExceptionType(T, New->getLocation()))
2256        continue;
2257
2258      Exceptions.push_back(T);
2259    }
2260    Expr *NoexceptExpr = 0;
2261    if (Expr *OldNoexceptExpr = Proto->getNoexceptExpr()) {
2262      EnterExpressionEvaluationContext Unevaluated(SemaRef, Sema::Unevaluated);
2263      ExprResult E = SemaRef.SubstExpr(OldNoexceptExpr, TemplateArgs);
2264      if (E.isUsable())
2265        NoexceptExpr = E.take();
2266    }
2267
2268    // Rebuild the function type
2269
2270    FunctionProtoType::ExtProtoInfo EPI = Proto->getExtProtoInfo();
2271    EPI.ExceptionSpecType = Proto->getExceptionSpecType();
2272    EPI.NumExceptions = Exceptions.size();
2273    EPI.Exceptions = Exceptions.data();
2274    EPI.NoexceptExpr = NoexceptExpr;
2275    EPI.ExtInfo = Proto->getExtInfo();
2276
2277    const FunctionProtoType *NewProto
2278      = New->getType()->getAs<FunctionProtoType>();
2279    assert(NewProto && "Template instantiation without function prototype?");
2280    New->setType(SemaRef.Context.getFunctionType(NewProto->getResultType(),
2281                                                 NewProto->arg_type_begin(),
2282                                                 NewProto->getNumArgs(),
2283                                                 EPI));
2284  }
2285
2286  SemaRef.InstantiateAttrs(TemplateArgs, Tmpl, New);
2287
2288  return false;
2289}
2290
2291/// \brief Initializes common fields of an instantiated method
2292/// declaration (New) from the corresponding fields of its template
2293/// (Tmpl).
2294///
2295/// \returns true if there was an error
2296bool
2297TemplateDeclInstantiator::InitMethodInstantiation(CXXMethodDecl *New,
2298                                                  CXXMethodDecl *Tmpl) {
2299  if (InitFunctionInstantiation(New, Tmpl))
2300    return true;
2301
2302  New->setAccess(Tmpl->getAccess());
2303  if (Tmpl->isVirtualAsWritten())
2304    New->setVirtualAsWritten(true);
2305
2306  // FIXME: attributes
2307  // FIXME: New needs a pointer to Tmpl
2308  return false;
2309}
2310
2311/// \brief Instantiate the definition of the given function from its
2312/// template.
2313///
2314/// \param PointOfInstantiation the point at which the instantiation was
2315/// required. Note that this is not precisely a "point of instantiation"
2316/// for the function, but it's close.
2317///
2318/// \param Function the already-instantiated declaration of a
2319/// function template specialization or member function of a class template
2320/// specialization.
2321///
2322/// \param Recursive if true, recursively instantiates any functions that
2323/// are required by this instantiation.
2324///
2325/// \param DefinitionRequired if true, then we are performing an explicit
2326/// instantiation where the body of the function is required. Complain if
2327/// there is no such body.
2328void Sema::InstantiateFunctionDefinition(SourceLocation PointOfInstantiation,
2329                                         FunctionDecl *Function,
2330                                         bool Recursive,
2331                                         bool DefinitionRequired) {
2332  if (Function->isInvalidDecl() || Function->isDefined())
2333    return;
2334
2335  // Never instantiate an explicit specialization.
2336  if (Function->getTemplateSpecializationKind() == TSK_ExplicitSpecialization)
2337    return;
2338
2339  // Find the function body that we'll be substituting.
2340  const FunctionDecl *PatternDecl = Function->getTemplateInstantiationPattern();
2341  assert(PatternDecl && "instantiating a non-template");
2342
2343  Stmt *Pattern = PatternDecl->getBody(PatternDecl);
2344  assert(PatternDecl && "template definition is not a template");
2345  if (!Pattern) {
2346    // Try to find a defaulted definition
2347    PatternDecl->isDefined(PatternDecl);
2348  }
2349  assert(PatternDecl && "template definition is not a template");
2350
2351  // Postpone late parsed template instantiations.
2352  if (PatternDecl->isLateTemplateParsed() &&
2353      !LateTemplateParser) {
2354    PendingInstantiations.push_back(
2355      std::make_pair(Function, PointOfInstantiation));
2356    return;
2357  }
2358
2359  // Call the LateTemplateParser callback if there a need to late parse
2360  // a templated function definition.
2361  if (!Pattern && PatternDecl->isLateTemplateParsed() &&
2362      LateTemplateParser) {
2363    LateTemplateParser(OpaqueParser, PatternDecl);
2364    Pattern = PatternDecl->getBody(PatternDecl);
2365  }
2366
2367  if (!Pattern && !PatternDecl->isDefaulted()) {
2368    if (DefinitionRequired) {
2369      if (Function->getPrimaryTemplate())
2370        Diag(PointOfInstantiation,
2371             diag::err_explicit_instantiation_undefined_func_template)
2372          << Function->getPrimaryTemplate();
2373      else
2374        Diag(PointOfInstantiation,
2375             diag::err_explicit_instantiation_undefined_member)
2376          << 1 << Function->getDeclName() << Function->getDeclContext();
2377
2378      if (PatternDecl)
2379        Diag(PatternDecl->getLocation(),
2380             diag::note_explicit_instantiation_here);
2381      Function->setInvalidDecl();
2382    } else if (Function->getTemplateSpecializationKind()
2383                 == TSK_ExplicitInstantiationDefinition) {
2384      PendingInstantiations.push_back(
2385        std::make_pair(Function, PointOfInstantiation));
2386    }
2387
2388    return;
2389  }
2390
2391  // C++0x [temp.explicit]p9:
2392  //   Except for inline functions, other explicit instantiation declarations
2393  //   have the effect of suppressing the implicit instantiation of the entity
2394  //   to which they refer.
2395  if (Function->getTemplateSpecializationKind()
2396        == TSK_ExplicitInstantiationDeclaration &&
2397      !PatternDecl->isInlined())
2398    return;
2399
2400  InstantiatingTemplate Inst(*this, PointOfInstantiation, Function);
2401  if (Inst)
2402    return;
2403
2404  // If we're performing recursive template instantiation, create our own
2405  // queue of pending implicit instantiations that we will instantiate later,
2406  // while we're still within our own instantiation context.
2407  llvm::SmallVector<VTableUse, 16> SavedVTableUses;
2408  std::deque<PendingImplicitInstantiation> SavedPendingInstantiations;
2409  if (Recursive) {
2410    VTableUses.swap(SavedVTableUses);
2411    PendingInstantiations.swap(SavedPendingInstantiations);
2412  }
2413
2414  EnterExpressionEvaluationContext EvalContext(*this,
2415                                               Sema::PotentiallyEvaluated);
2416  ActOnStartOfFunctionDef(0, Function);
2417
2418  // Introduce a new scope where local variable instantiations will be
2419  // recorded, unless we're actually a member function within a local
2420  // class, in which case we need to merge our results with the parent
2421  // scope (of the enclosing function).
2422  bool MergeWithParentScope = false;
2423  if (CXXRecordDecl *Rec = dyn_cast<CXXRecordDecl>(Function->getDeclContext()))
2424    MergeWithParentScope = Rec->isLocalClass();
2425
2426  LocalInstantiationScope Scope(*this, MergeWithParentScope);
2427
2428  // Introduce the instantiated function parameters into the local
2429  // instantiation scope, and set the parameter names to those used
2430  // in the template.
2431  unsigned FParamIdx = 0;
2432  for (unsigned I = 0, N = PatternDecl->getNumParams(); I != N; ++I) {
2433    const ParmVarDecl *PatternParam = PatternDecl->getParamDecl(I);
2434    if (!PatternParam->isParameterPack()) {
2435      // Simple case: not a parameter pack.
2436      assert(FParamIdx < Function->getNumParams());
2437      ParmVarDecl *FunctionParam = Function->getParamDecl(I);
2438      FunctionParam->setDeclName(PatternParam->getDeclName());
2439      Scope.InstantiatedLocal(PatternParam, FunctionParam);
2440      ++FParamIdx;
2441      continue;
2442    }
2443
2444    // Expand the parameter pack.
2445    Scope.MakeInstantiatedLocalArgPack(PatternParam);
2446    for (unsigned NumFParams = Function->getNumParams();
2447         FParamIdx < NumFParams;
2448         ++FParamIdx) {
2449      ParmVarDecl *FunctionParam = Function->getParamDecl(FParamIdx);
2450      FunctionParam->setDeclName(PatternParam->getDeclName());
2451      Scope.InstantiatedLocalPackArg(PatternParam, FunctionParam);
2452    }
2453  }
2454
2455  // Enter the scope of this instantiation. We don't use
2456  // PushDeclContext because we don't have a scope.
2457  Sema::ContextRAII savedContext(*this, Function);
2458
2459  MultiLevelTemplateArgumentList TemplateArgs =
2460    getTemplateInstantiationArgs(Function, 0, false, PatternDecl);
2461
2462  if (PatternDecl->isDefaulted()) {
2463    ActOnFinishFunctionBody(Function, 0, /*IsInstantiation=*/true);
2464
2465    SetDeclDefaulted(Function, PatternDecl->getLocation());
2466  } else {
2467    // If this is a constructor, instantiate the member initializers.
2468    if (const CXXConstructorDecl *Ctor =
2469          dyn_cast<CXXConstructorDecl>(PatternDecl)) {
2470      InstantiateMemInitializers(cast<CXXConstructorDecl>(Function), Ctor,
2471                                 TemplateArgs);
2472    }
2473
2474    // Instantiate the function body.
2475    StmtResult Body = SubstStmt(Pattern, TemplateArgs);
2476
2477    if (Body.isInvalid())
2478      Function->setInvalidDecl();
2479
2480    ActOnFinishFunctionBody(Function, Body.get(),
2481                            /*IsInstantiation=*/true);
2482  }
2483
2484  PerformDependentDiagnostics(PatternDecl, TemplateArgs);
2485
2486  savedContext.pop();
2487
2488  DeclGroupRef DG(Function);
2489  Consumer.HandleTopLevelDecl(DG);
2490
2491  // This class may have local implicit instantiations that need to be
2492  // instantiation within this scope.
2493  PerformPendingInstantiations(/*LocalOnly=*/true);
2494  Scope.Exit();
2495
2496  if (Recursive) {
2497    // Define any pending vtables.
2498    DefineUsedVTables();
2499
2500    // Instantiate any pending implicit instantiations found during the
2501    // instantiation of this template.
2502    PerformPendingInstantiations();
2503
2504    // Restore the set of pending vtables.
2505    assert(VTableUses.empty() &&
2506           "VTableUses should be empty before it is discarded.");
2507    VTableUses.swap(SavedVTableUses);
2508
2509    // Restore the set of pending implicit instantiations.
2510    assert(PendingInstantiations.empty() &&
2511           "PendingInstantiations should be empty before it is discarded.");
2512    PendingInstantiations.swap(SavedPendingInstantiations);
2513  }
2514}
2515
2516/// \brief Instantiate the definition of the given variable from its
2517/// template.
2518///
2519/// \param PointOfInstantiation the point at which the instantiation was
2520/// required. Note that this is not precisely a "point of instantiation"
2521/// for the function, but it's close.
2522///
2523/// \param Var the already-instantiated declaration of a static member
2524/// variable of a class template specialization.
2525///
2526/// \param Recursive if true, recursively instantiates any functions that
2527/// are required by this instantiation.
2528///
2529/// \param DefinitionRequired if true, then we are performing an explicit
2530/// instantiation where an out-of-line definition of the member variable
2531/// is required. Complain if there is no such definition.
2532void Sema::InstantiateStaticDataMemberDefinition(
2533                                          SourceLocation PointOfInstantiation,
2534                                                 VarDecl *Var,
2535                                                 bool Recursive,
2536                                                 bool DefinitionRequired) {
2537  if (Var->isInvalidDecl())
2538    return;
2539
2540  // Find the out-of-line definition of this static data member.
2541  VarDecl *Def = Var->getInstantiatedFromStaticDataMember();
2542  assert(Def && "This data member was not instantiated from a template?");
2543  assert(Def->isStaticDataMember() && "Not a static data member?");
2544  Def = Def->getOutOfLineDefinition();
2545
2546  if (!Def) {
2547    // We did not find an out-of-line definition of this static data member,
2548    // so we won't perform any instantiation. Rather, we rely on the user to
2549    // instantiate this definition (or provide a specialization for it) in
2550    // another translation unit.
2551    if (DefinitionRequired) {
2552      Def = Var->getInstantiatedFromStaticDataMember();
2553      Diag(PointOfInstantiation,
2554           diag::err_explicit_instantiation_undefined_member)
2555        << 2 << Var->getDeclName() << Var->getDeclContext();
2556      Diag(Def->getLocation(), diag::note_explicit_instantiation_here);
2557    } else if (Var->getTemplateSpecializationKind()
2558                 == TSK_ExplicitInstantiationDefinition) {
2559      PendingInstantiations.push_back(
2560        std::make_pair(Var, PointOfInstantiation));
2561    }
2562
2563    return;
2564  }
2565
2566  // Never instantiate an explicit specialization.
2567  if (Var->getTemplateSpecializationKind() == TSK_ExplicitSpecialization)
2568    return;
2569
2570  // C++0x [temp.explicit]p9:
2571  //   Except for inline functions, other explicit instantiation declarations
2572  //   have the effect of suppressing the implicit instantiation of the entity
2573  //   to which they refer.
2574  if (Var->getTemplateSpecializationKind()
2575        == TSK_ExplicitInstantiationDeclaration)
2576    return;
2577
2578  // If we already have a definition, we're done.
2579  if (Var->getDefinition())
2580    return;
2581
2582  InstantiatingTemplate Inst(*this, PointOfInstantiation, Var);
2583  if (Inst)
2584    return;
2585
2586  // If we're performing recursive template instantiation, create our own
2587  // queue of pending implicit instantiations that we will instantiate later,
2588  // while we're still within our own instantiation context.
2589  llvm::SmallVector<VTableUse, 16> SavedVTableUses;
2590  std::deque<PendingImplicitInstantiation> SavedPendingInstantiations;
2591  if (Recursive) {
2592    VTableUses.swap(SavedVTableUses);
2593    PendingInstantiations.swap(SavedPendingInstantiations);
2594  }
2595
2596  // Enter the scope of this instantiation. We don't use
2597  // PushDeclContext because we don't have a scope.
2598  ContextRAII previousContext(*this, Var->getDeclContext());
2599
2600  VarDecl *OldVar = Var;
2601  Var = cast_or_null<VarDecl>(SubstDecl(Def, Var->getDeclContext(),
2602                                        getTemplateInstantiationArgs(Var)));
2603
2604  previousContext.pop();
2605
2606  if (Var) {
2607    MemberSpecializationInfo *MSInfo = OldVar->getMemberSpecializationInfo();
2608    assert(MSInfo && "Missing member specialization information?");
2609    Var->setTemplateSpecializationKind(MSInfo->getTemplateSpecializationKind(),
2610                                       MSInfo->getPointOfInstantiation());
2611    DeclGroupRef DG(Var);
2612    Consumer.HandleTopLevelDecl(DG);
2613  }
2614
2615  if (Recursive) {
2616    // Define any newly required vtables.
2617    DefineUsedVTables();
2618
2619    // Instantiate any pending implicit instantiations found during the
2620    // instantiation of this template.
2621    PerformPendingInstantiations();
2622
2623    // Restore the set of pending vtables.
2624    assert(VTableUses.empty() &&
2625           "VTableUses should be empty before it is discarded, "
2626           "while instantiating static data member.");
2627    VTableUses.swap(SavedVTableUses);
2628
2629    // Restore the set of pending implicit instantiations.
2630    assert(PendingInstantiations.empty() &&
2631           "PendingInstantiations should be empty before it is discarded, "
2632           "while instantiating static data member.");
2633    PendingInstantiations.swap(SavedPendingInstantiations);
2634  }
2635}
2636
2637void
2638Sema::InstantiateMemInitializers(CXXConstructorDecl *New,
2639                                 const CXXConstructorDecl *Tmpl,
2640                           const MultiLevelTemplateArgumentList &TemplateArgs) {
2641
2642  llvm::SmallVector<MemInitTy*, 4> NewInits;
2643  bool AnyErrors = false;
2644
2645  // Instantiate all the initializers.
2646  for (CXXConstructorDecl::init_const_iterator Inits = Tmpl->init_begin(),
2647                                            InitsEnd = Tmpl->init_end();
2648       Inits != InitsEnd; ++Inits) {
2649    CXXCtorInitializer *Init = *Inits;
2650
2651    // Only instantiate written initializers, let Sema re-construct implicit
2652    // ones.
2653    if (!Init->isWritten())
2654      continue;
2655
2656    SourceLocation LParenLoc, RParenLoc;
2657    ASTOwningVector<Expr*> NewArgs(*this);
2658
2659    SourceLocation EllipsisLoc;
2660
2661    if (Init->isPackExpansion()) {
2662      // This is a pack expansion. We should expand it now.
2663      TypeLoc BaseTL = Init->getBaseClassInfo()->getTypeLoc();
2664      llvm::SmallVector<UnexpandedParameterPack, 2> Unexpanded;
2665      collectUnexpandedParameterPacks(BaseTL, Unexpanded);
2666      bool ShouldExpand = false;
2667      bool RetainExpansion = false;
2668      llvm::Optional<unsigned> NumExpansions;
2669      if (CheckParameterPacksForExpansion(Init->getEllipsisLoc(),
2670                                          BaseTL.getSourceRange(),
2671                                          Unexpanded.data(),
2672                                          Unexpanded.size(),
2673                                          TemplateArgs, ShouldExpand,
2674                                          RetainExpansion,
2675                                          NumExpansions)) {
2676        AnyErrors = true;
2677        New->setInvalidDecl();
2678        continue;
2679      }
2680      assert(ShouldExpand && "Partial instantiation of base initializer?");
2681
2682      // Loop over all of the arguments in the argument pack(s),
2683      for (unsigned I = 0; I != *NumExpansions; ++I) {
2684        Sema::ArgumentPackSubstitutionIndexRAII SubstIndex(*this, I);
2685
2686        // Instantiate the initializer.
2687        if (InstantiateInitializer(*this, Init->getInit(), TemplateArgs,
2688                                   LParenLoc, NewArgs, RParenLoc)) {
2689          AnyErrors = true;
2690          break;
2691        }
2692
2693        // Instantiate the base type.
2694        TypeSourceInfo *BaseTInfo = SubstType(Init->getBaseClassInfo(),
2695                                              TemplateArgs,
2696                                              Init->getSourceLocation(),
2697                                              New->getDeclName());
2698        if (!BaseTInfo) {
2699          AnyErrors = true;
2700          break;
2701        }
2702
2703        // Build the initializer.
2704        MemInitResult NewInit = BuildBaseInitializer(BaseTInfo->getType(),
2705                                                     BaseTInfo,
2706                                                     (Expr **)NewArgs.data(),
2707                                                     NewArgs.size(),
2708                                                     Init->getLParenLoc(),
2709                                                     Init->getRParenLoc(),
2710                                                     New->getParent(),
2711                                                     SourceLocation());
2712        if (NewInit.isInvalid()) {
2713          AnyErrors = true;
2714          break;
2715        }
2716
2717        NewInits.push_back(NewInit.get());
2718        NewArgs.clear();
2719      }
2720
2721      continue;
2722    }
2723
2724    // Instantiate the initializer.
2725    if (InstantiateInitializer(*this, Init->getInit(), TemplateArgs,
2726                               LParenLoc, NewArgs, RParenLoc)) {
2727      AnyErrors = true;
2728      continue;
2729    }
2730
2731    MemInitResult NewInit;
2732    if (Init->isBaseInitializer()) {
2733      TypeSourceInfo *BaseTInfo = SubstType(Init->getBaseClassInfo(),
2734                                            TemplateArgs,
2735                                            Init->getSourceLocation(),
2736                                            New->getDeclName());
2737      if (!BaseTInfo) {
2738        AnyErrors = true;
2739        New->setInvalidDecl();
2740        continue;
2741      }
2742
2743      NewInit = BuildBaseInitializer(BaseTInfo->getType(), BaseTInfo,
2744                                     (Expr **)NewArgs.data(),
2745                                     NewArgs.size(),
2746                                     Init->getLParenLoc(),
2747                                     Init->getRParenLoc(),
2748                                     New->getParent(),
2749                                     EllipsisLoc);
2750    } else if (Init->isMemberInitializer()) {
2751      FieldDecl *Member = cast_or_null<FieldDecl>(FindInstantiatedDecl(
2752                                                     Init->getMemberLocation(),
2753                                                     Init->getMember(),
2754                                                     TemplateArgs));
2755      if (!Member) {
2756        AnyErrors = true;
2757        New->setInvalidDecl();
2758        continue;
2759      }
2760
2761      NewInit = BuildMemberInitializer(Member, (Expr **)NewArgs.data(),
2762                                       NewArgs.size(),
2763                                       Init->getSourceLocation(),
2764                                       Init->getLParenLoc(),
2765                                       Init->getRParenLoc());
2766    } else if (Init->isIndirectMemberInitializer()) {
2767      IndirectFieldDecl *IndirectMember =
2768         cast_or_null<IndirectFieldDecl>(FindInstantiatedDecl(
2769                                 Init->getMemberLocation(),
2770                                 Init->getIndirectMember(), TemplateArgs));
2771
2772      if (!IndirectMember) {
2773        AnyErrors = true;
2774        New->setInvalidDecl();
2775        continue;
2776      }
2777
2778      NewInit = BuildMemberInitializer(IndirectMember, (Expr **)NewArgs.data(),
2779                                       NewArgs.size(),
2780                                       Init->getSourceLocation(),
2781                                       Init->getLParenLoc(),
2782                                       Init->getRParenLoc());
2783    }
2784
2785    if (NewInit.isInvalid()) {
2786      AnyErrors = true;
2787      New->setInvalidDecl();
2788    } else {
2789      // FIXME: It would be nice if ASTOwningVector had a release function.
2790      NewArgs.take();
2791
2792      NewInits.push_back((MemInitTy *)NewInit.get());
2793    }
2794  }
2795
2796  // Assign all the initializers to the new constructor.
2797  ActOnMemInitializers(New,
2798                       /*FIXME: ColonLoc */
2799                       SourceLocation(),
2800                       NewInits.data(), NewInits.size(),
2801                       AnyErrors);
2802}
2803
2804// TODO: this could be templated if the various decl types used the
2805// same method name.
2806static bool isInstantiationOf(ClassTemplateDecl *Pattern,
2807                              ClassTemplateDecl *Instance) {
2808  Pattern = Pattern->getCanonicalDecl();
2809
2810  do {
2811    Instance = Instance->getCanonicalDecl();
2812    if (Pattern == Instance) return true;
2813    Instance = Instance->getInstantiatedFromMemberTemplate();
2814  } while (Instance);
2815
2816  return false;
2817}
2818
2819static bool isInstantiationOf(FunctionTemplateDecl *Pattern,
2820                              FunctionTemplateDecl *Instance) {
2821  Pattern = Pattern->getCanonicalDecl();
2822
2823  do {
2824    Instance = Instance->getCanonicalDecl();
2825    if (Pattern == Instance) return true;
2826    Instance = Instance->getInstantiatedFromMemberTemplate();
2827  } while (Instance);
2828
2829  return false;
2830}
2831
2832static bool
2833isInstantiationOf(ClassTemplatePartialSpecializationDecl *Pattern,
2834                  ClassTemplatePartialSpecializationDecl *Instance) {
2835  Pattern
2836    = cast<ClassTemplatePartialSpecializationDecl>(Pattern->getCanonicalDecl());
2837  do {
2838    Instance = cast<ClassTemplatePartialSpecializationDecl>(
2839                                                Instance->getCanonicalDecl());
2840    if (Pattern == Instance)
2841      return true;
2842    Instance = Instance->getInstantiatedFromMember();
2843  } while (Instance);
2844
2845  return false;
2846}
2847
2848static bool isInstantiationOf(CXXRecordDecl *Pattern,
2849                              CXXRecordDecl *Instance) {
2850  Pattern = Pattern->getCanonicalDecl();
2851
2852  do {
2853    Instance = Instance->getCanonicalDecl();
2854    if (Pattern == Instance) return true;
2855    Instance = Instance->getInstantiatedFromMemberClass();
2856  } while (Instance);
2857
2858  return false;
2859}
2860
2861static bool isInstantiationOf(FunctionDecl *Pattern,
2862                              FunctionDecl *Instance) {
2863  Pattern = Pattern->getCanonicalDecl();
2864
2865  do {
2866    Instance = Instance->getCanonicalDecl();
2867    if (Pattern == Instance) return true;
2868    Instance = Instance->getInstantiatedFromMemberFunction();
2869  } while (Instance);
2870
2871  return false;
2872}
2873
2874static bool isInstantiationOf(EnumDecl *Pattern,
2875                              EnumDecl *Instance) {
2876  Pattern = Pattern->getCanonicalDecl();
2877
2878  do {
2879    Instance = Instance->getCanonicalDecl();
2880    if (Pattern == Instance) return true;
2881    Instance = Instance->getInstantiatedFromMemberEnum();
2882  } while (Instance);
2883
2884  return false;
2885}
2886
2887static bool isInstantiationOf(UsingShadowDecl *Pattern,
2888                              UsingShadowDecl *Instance,
2889                              ASTContext &C) {
2890  return C.getInstantiatedFromUsingShadowDecl(Instance) == Pattern;
2891}
2892
2893static bool isInstantiationOf(UsingDecl *Pattern,
2894                              UsingDecl *Instance,
2895                              ASTContext &C) {
2896  return C.getInstantiatedFromUsingDecl(Instance) == Pattern;
2897}
2898
2899static bool isInstantiationOf(UnresolvedUsingValueDecl *Pattern,
2900                              UsingDecl *Instance,
2901                              ASTContext &C) {
2902  return C.getInstantiatedFromUsingDecl(Instance) == Pattern;
2903}
2904
2905static bool isInstantiationOf(UnresolvedUsingTypenameDecl *Pattern,
2906                              UsingDecl *Instance,
2907                              ASTContext &C) {
2908  return C.getInstantiatedFromUsingDecl(Instance) == Pattern;
2909}
2910
2911static bool isInstantiationOfStaticDataMember(VarDecl *Pattern,
2912                                              VarDecl *Instance) {
2913  assert(Instance->isStaticDataMember());
2914
2915  Pattern = Pattern->getCanonicalDecl();
2916
2917  do {
2918    Instance = Instance->getCanonicalDecl();
2919    if (Pattern == Instance) return true;
2920    Instance = Instance->getInstantiatedFromStaticDataMember();
2921  } while (Instance);
2922
2923  return false;
2924}
2925
2926// Other is the prospective instantiation
2927// D is the prospective pattern
2928static bool isInstantiationOf(ASTContext &Ctx, NamedDecl *D, Decl *Other) {
2929  if (D->getKind() != Other->getKind()) {
2930    if (UnresolvedUsingTypenameDecl *UUD
2931          = dyn_cast<UnresolvedUsingTypenameDecl>(D)) {
2932      if (UsingDecl *UD = dyn_cast<UsingDecl>(Other)) {
2933        return isInstantiationOf(UUD, UD, Ctx);
2934      }
2935    }
2936
2937    if (UnresolvedUsingValueDecl *UUD
2938          = dyn_cast<UnresolvedUsingValueDecl>(D)) {
2939      if (UsingDecl *UD = dyn_cast<UsingDecl>(Other)) {
2940        return isInstantiationOf(UUD, UD, Ctx);
2941      }
2942    }
2943
2944    return false;
2945  }
2946
2947  if (CXXRecordDecl *Record = dyn_cast<CXXRecordDecl>(Other))
2948    return isInstantiationOf(cast<CXXRecordDecl>(D), Record);
2949
2950  if (FunctionDecl *Function = dyn_cast<FunctionDecl>(Other))
2951    return isInstantiationOf(cast<FunctionDecl>(D), Function);
2952
2953  if (EnumDecl *Enum = dyn_cast<EnumDecl>(Other))
2954    return isInstantiationOf(cast<EnumDecl>(D), Enum);
2955
2956  if (VarDecl *Var = dyn_cast<VarDecl>(Other))
2957    if (Var->isStaticDataMember())
2958      return isInstantiationOfStaticDataMember(cast<VarDecl>(D), Var);
2959
2960  if (ClassTemplateDecl *Temp = dyn_cast<ClassTemplateDecl>(Other))
2961    return isInstantiationOf(cast<ClassTemplateDecl>(D), Temp);
2962
2963  if (FunctionTemplateDecl *Temp = dyn_cast<FunctionTemplateDecl>(Other))
2964    return isInstantiationOf(cast<FunctionTemplateDecl>(D), Temp);
2965
2966  if (ClassTemplatePartialSpecializationDecl *PartialSpec
2967        = dyn_cast<ClassTemplatePartialSpecializationDecl>(Other))
2968    return isInstantiationOf(cast<ClassTemplatePartialSpecializationDecl>(D),
2969                             PartialSpec);
2970
2971  if (FieldDecl *Field = dyn_cast<FieldDecl>(Other)) {
2972    if (!Field->getDeclName()) {
2973      // This is an unnamed field.
2974      return Ctx.getInstantiatedFromUnnamedFieldDecl(Field) ==
2975        cast<FieldDecl>(D);
2976    }
2977  }
2978
2979  if (UsingDecl *Using = dyn_cast<UsingDecl>(Other))
2980    return isInstantiationOf(cast<UsingDecl>(D), Using, Ctx);
2981
2982  if (UsingShadowDecl *Shadow = dyn_cast<UsingShadowDecl>(Other))
2983    return isInstantiationOf(cast<UsingShadowDecl>(D), Shadow, Ctx);
2984
2985  return D->getDeclName() && isa<NamedDecl>(Other) &&
2986    D->getDeclName() == cast<NamedDecl>(Other)->getDeclName();
2987}
2988
2989template<typename ForwardIterator>
2990static NamedDecl *findInstantiationOf(ASTContext &Ctx,
2991                                      NamedDecl *D,
2992                                      ForwardIterator first,
2993                                      ForwardIterator last) {
2994  for (; first != last; ++first)
2995    if (isInstantiationOf(Ctx, D, *first))
2996      return cast<NamedDecl>(*first);
2997
2998  return 0;
2999}
3000
3001/// \brief Finds the instantiation of the given declaration context
3002/// within the current instantiation.
3003///
3004/// \returns NULL if there was an error
3005DeclContext *Sema::FindInstantiatedContext(SourceLocation Loc, DeclContext* DC,
3006                          const MultiLevelTemplateArgumentList &TemplateArgs) {
3007  if (NamedDecl *D = dyn_cast<NamedDecl>(DC)) {
3008    Decl* ID = FindInstantiatedDecl(Loc, D, TemplateArgs);
3009    return cast_or_null<DeclContext>(ID);
3010  } else return DC;
3011}
3012
3013/// \brief Find the instantiation of the given declaration within the
3014/// current instantiation.
3015///
3016/// This routine is intended to be used when \p D is a declaration
3017/// referenced from within a template, that needs to mapped into the
3018/// corresponding declaration within an instantiation. For example,
3019/// given:
3020///
3021/// \code
3022/// template<typename T>
3023/// struct X {
3024///   enum Kind {
3025///     KnownValue = sizeof(T)
3026///   };
3027///
3028///   bool getKind() const { return KnownValue; }
3029/// };
3030///
3031/// template struct X<int>;
3032/// \endcode
3033///
3034/// In the instantiation of X<int>::getKind(), we need to map the
3035/// EnumConstantDecl for KnownValue (which refers to
3036/// X<T>::<Kind>::KnownValue) to its instantiation
3037/// (X<int>::<Kind>::KnownValue). InstantiateCurrentDeclRef() performs
3038/// this mapping from within the instantiation of X<int>.
3039NamedDecl *Sema::FindInstantiatedDecl(SourceLocation Loc, NamedDecl *D,
3040                          const MultiLevelTemplateArgumentList &TemplateArgs) {
3041  DeclContext *ParentDC = D->getDeclContext();
3042  if (isa<ParmVarDecl>(D) || isa<NonTypeTemplateParmDecl>(D) ||
3043      isa<TemplateTypeParmDecl>(D) || isa<TemplateTemplateParmDecl>(D) ||
3044      (ParentDC->isFunctionOrMethod() && ParentDC->isDependentContext())) {
3045    // D is a local of some kind. Look into the map of local
3046    // declarations to their instantiations.
3047    typedef LocalInstantiationScope::DeclArgumentPack DeclArgumentPack;
3048    llvm::PointerUnion<Decl *, DeclArgumentPack *> *Found
3049      = CurrentInstantiationScope->findInstantiationOf(D);
3050
3051    if (Found) {
3052      if (Decl *FD = Found->dyn_cast<Decl *>())
3053        return cast<NamedDecl>(FD);
3054
3055      unsigned PackIdx = ArgumentPackSubstitutionIndex;
3056      return cast<NamedDecl>((*Found->get<DeclArgumentPack *>())[PackIdx]);
3057    }
3058
3059    // If we didn't find the decl, then we must have a label decl that hasn't
3060    // been found yet.  Lazily instantiate it and return it now.
3061    assert(isa<LabelDecl>(D));
3062
3063    Decl *Inst = SubstDecl(D, CurContext, TemplateArgs);
3064    assert(Inst && "Failed to instantiate label??");
3065
3066    CurrentInstantiationScope->InstantiatedLocal(D, Inst);
3067    return cast<LabelDecl>(Inst);
3068  }
3069
3070  if (CXXRecordDecl *Record = dyn_cast<CXXRecordDecl>(D)) {
3071    if (!Record->isDependentContext())
3072      return D;
3073
3074    // If the RecordDecl is actually the injected-class-name or a
3075    // "templated" declaration for a class template, class template
3076    // partial specialization, or a member class of a class template,
3077    // substitute into the injected-class-name of the class template
3078    // or partial specialization to find the new DeclContext.
3079    QualType T;
3080    ClassTemplateDecl *ClassTemplate = Record->getDescribedClassTemplate();
3081
3082    if (ClassTemplate) {
3083      T = ClassTemplate->getInjectedClassNameSpecialization();
3084    } else if (ClassTemplatePartialSpecializationDecl *PartialSpec
3085                 = dyn_cast<ClassTemplatePartialSpecializationDecl>(Record)) {
3086      ClassTemplate = PartialSpec->getSpecializedTemplate();
3087
3088      // If we call SubstType with an InjectedClassNameType here we
3089      // can end up in an infinite loop.
3090      T = Context.getTypeDeclType(Record);
3091      assert(isa<InjectedClassNameType>(T) &&
3092             "type of partial specialization is not an InjectedClassNameType");
3093      T = cast<InjectedClassNameType>(T)->getInjectedSpecializationType();
3094    }
3095
3096    if (!T.isNull()) {
3097      // Substitute into the injected-class-name to get the type
3098      // corresponding to the instantiation we want, which may also be
3099      // the current instantiation (if we're in a template
3100      // definition). This substitution should never fail, since we
3101      // know we can instantiate the injected-class-name or we
3102      // wouldn't have gotten to the injected-class-name!
3103
3104      // FIXME: Can we use the CurrentInstantiationScope to avoid this
3105      // extra instantiation in the common case?
3106      T = SubstType(T, TemplateArgs, Loc, DeclarationName());
3107      assert(!T.isNull() && "Instantiation of injected-class-name cannot fail.");
3108
3109      if (!T->isDependentType()) {
3110        assert(T->isRecordType() && "Instantiation must produce a record type");
3111        return T->getAs<RecordType>()->getDecl();
3112      }
3113
3114      // We are performing "partial" template instantiation to create
3115      // the member declarations for the members of a class template
3116      // specialization. Therefore, D is actually referring to something
3117      // in the current instantiation. Look through the current
3118      // context, which contains actual instantiations, to find the
3119      // instantiation of the "current instantiation" that D refers
3120      // to.
3121      bool SawNonDependentContext = false;
3122      for (DeclContext *DC = CurContext; !DC->isFileContext();
3123           DC = DC->getParent()) {
3124        if (ClassTemplateSpecializationDecl *Spec
3125                          = dyn_cast<ClassTemplateSpecializationDecl>(DC))
3126          if (isInstantiationOf(ClassTemplate,
3127                                Spec->getSpecializedTemplate()))
3128            return Spec;
3129
3130        if (!DC->isDependentContext())
3131          SawNonDependentContext = true;
3132      }
3133
3134      // We're performing "instantiation" of a member of the current
3135      // instantiation while we are type-checking the
3136      // definition. Compute the declaration context and return that.
3137      assert(!SawNonDependentContext &&
3138             "No dependent context while instantiating record");
3139      DeclContext *DC = computeDeclContext(T);
3140      assert(DC &&
3141             "Unable to find declaration for the current instantiation");
3142      return cast<CXXRecordDecl>(DC);
3143    }
3144
3145    // Fall through to deal with other dependent record types (e.g.,
3146    // anonymous unions in class templates).
3147  }
3148
3149  if (!ParentDC->isDependentContext())
3150    return D;
3151
3152  ParentDC = FindInstantiatedContext(Loc, ParentDC, TemplateArgs);
3153  if (!ParentDC)
3154    return 0;
3155
3156  if (ParentDC != D->getDeclContext()) {
3157    // We performed some kind of instantiation in the parent context,
3158    // so now we need to look into the instantiated parent context to
3159    // find the instantiation of the declaration D.
3160
3161    // If our context used to be dependent, we may need to instantiate
3162    // it before performing lookup into that context.
3163    bool IsBeingInstantiated = false;
3164    if (CXXRecordDecl *Spec = dyn_cast<CXXRecordDecl>(ParentDC)) {
3165      if (!Spec->isDependentContext()) {
3166        QualType T = Context.getTypeDeclType(Spec);
3167        const RecordType *Tag = T->getAs<RecordType>();
3168        assert(Tag && "type of non-dependent record is not a RecordType");
3169        if (Tag->isBeingDefined())
3170          IsBeingInstantiated = true;
3171        if (!Tag->isBeingDefined() &&
3172            RequireCompleteType(Loc, T, diag::err_incomplete_type))
3173          return 0;
3174
3175        ParentDC = Tag->getDecl();
3176      }
3177    }
3178
3179    NamedDecl *Result = 0;
3180    if (D->getDeclName()) {
3181      DeclContext::lookup_result Found = ParentDC->lookup(D->getDeclName());
3182      Result = findInstantiationOf(Context, D, Found.first, Found.second);
3183    } else {
3184      // Since we don't have a name for the entity we're looking for,
3185      // our only option is to walk through all of the declarations to
3186      // find that name. This will occur in a few cases:
3187      //
3188      //   - anonymous struct/union within a template
3189      //   - unnamed class/struct/union/enum within a template
3190      //
3191      // FIXME: Find a better way to find these instantiations!
3192      Result = findInstantiationOf(Context, D,
3193                                   ParentDC->decls_begin(),
3194                                   ParentDC->decls_end());
3195    }
3196
3197    if (!Result) {
3198      if (isa<UsingShadowDecl>(D)) {
3199        // UsingShadowDecls can instantiate to nothing because of using hiding.
3200      } else if (Diags.hasErrorOccurred()) {
3201        // We've already complained about something, so most likely this
3202        // declaration failed to instantiate. There's no point in complaining
3203        // further, since this is normal in invalid code.
3204      } else if (IsBeingInstantiated) {
3205        // The class in which this member exists is currently being
3206        // instantiated, and we haven't gotten around to instantiating this
3207        // member yet. This can happen when the code uses forward declarations
3208        // of member classes, and introduces ordering dependencies via
3209        // template instantiation.
3210        Diag(Loc, diag::err_member_not_yet_instantiated)
3211          << D->getDeclName()
3212          << Context.getTypeDeclType(cast<CXXRecordDecl>(ParentDC));
3213        Diag(D->getLocation(), diag::note_non_instantiated_member_here);
3214      } else {
3215        // We should have found something, but didn't.
3216        llvm_unreachable("Unable to find instantiation of declaration!");
3217      }
3218    }
3219
3220    D = Result;
3221  }
3222
3223  return D;
3224}
3225
3226/// \brief Performs template instantiation for all implicit template
3227/// instantiations we have seen until this point.
3228void Sema::PerformPendingInstantiations(bool LocalOnly) {
3229  while (!PendingLocalImplicitInstantiations.empty() ||
3230         (!LocalOnly && !PendingInstantiations.empty())) {
3231    PendingImplicitInstantiation Inst;
3232
3233    if (PendingLocalImplicitInstantiations.empty()) {
3234      Inst = PendingInstantiations.front();
3235      PendingInstantiations.pop_front();
3236    } else {
3237      Inst = PendingLocalImplicitInstantiations.front();
3238      PendingLocalImplicitInstantiations.pop_front();
3239    }
3240
3241    // Instantiate function definitions
3242    if (FunctionDecl *Function = dyn_cast<FunctionDecl>(Inst.first)) {
3243      PrettyDeclStackTraceEntry CrashInfo(*this, Function, SourceLocation(),
3244                                          "instantiating function definition");
3245      bool DefinitionRequired = Function->getTemplateSpecializationKind() ==
3246                                TSK_ExplicitInstantiationDefinition;
3247      InstantiateFunctionDefinition(/*FIXME:*/Inst.second, Function, true,
3248                                    DefinitionRequired);
3249      continue;
3250    }
3251
3252    // Instantiate static data member definitions.
3253    VarDecl *Var = cast<VarDecl>(Inst.first);
3254    assert(Var->isStaticDataMember() && "Not a static data member?");
3255
3256    // Don't try to instantiate declarations if the most recent redeclaration
3257    // is invalid.
3258    if (Var->getMostRecentDeclaration()->isInvalidDecl())
3259      continue;
3260
3261    // Check if the most recent declaration has changed the specialization kind
3262    // and removed the need for implicit instantiation.
3263    switch (Var->getMostRecentDeclaration()->getTemplateSpecializationKind()) {
3264    case TSK_Undeclared:
3265      assert(false && "Cannot instantitiate an undeclared specialization.");
3266    case TSK_ExplicitInstantiationDeclaration:
3267    case TSK_ExplicitSpecialization:
3268      continue;  // No longer need to instantiate this type.
3269    case TSK_ExplicitInstantiationDefinition:
3270      // We only need an instantiation if the pending instantiation *is* the
3271      // explicit instantiation.
3272      if (Var != Var->getMostRecentDeclaration()) continue;
3273    case TSK_ImplicitInstantiation:
3274      break;
3275    }
3276
3277    PrettyDeclStackTraceEntry CrashInfo(*this, Var, Var->getLocation(),
3278                                        "instantiating static data member "
3279                                        "definition");
3280
3281    bool DefinitionRequired = Var->getTemplateSpecializationKind() ==
3282                              TSK_ExplicitInstantiationDefinition;
3283    InstantiateStaticDataMemberDefinition(/*FIXME:*/Inst.second, Var, true,
3284                                          DefinitionRequired);
3285  }
3286}
3287
3288void Sema::PerformDependentDiagnostics(const DeclContext *Pattern,
3289                       const MultiLevelTemplateArgumentList &TemplateArgs) {
3290  for (DeclContext::ddiag_iterator I = Pattern->ddiag_begin(),
3291         E = Pattern->ddiag_end(); I != E; ++I) {
3292    DependentDiagnostic *DD = *I;
3293
3294    switch (DD->getKind()) {
3295    case DependentDiagnostic::Access:
3296      HandleDependentAccessCheck(*DD, TemplateArgs);
3297      break;
3298    }
3299  }
3300}
3301