SemaTemplateInstantiateDecl.cpp revision 83972f128e9218c051692bf96361327a701aeb79 
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/AST/ASTConsumer.h"
14#include "clang/AST/ASTContext.h"
15#include "clang/AST/DeclTemplate.h"
16#include "clang/AST/DeclVisitor.h"
17#include "clang/AST/DependentDiagnostic.h"
18#include "clang/AST/Expr.h"
19#include "clang/AST/ExprCXX.h"
20#include "clang/AST/TypeLoc.h"
21#include "clang/Lex/Preprocessor.h"
22#include "clang/Sema/Lookup.h"
23#include "clang/Sema/PrettyDeclStackTrace.h"
24#include "clang/Sema/Template.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// Include attribute instantiation code.
61#include "clang/Sema/AttrTemplateInstantiate.inc"
62
63static void instantiateDependentAlignedAttr(
64    Sema &S, const MultiLevelTemplateArgumentList &TemplateArgs,
65    const AlignedAttr *Aligned, Decl *New, bool IsPackExpansion) {
66  if (Aligned->isAlignmentExpr()) {
67    // The alignment expression is a constant expression.
68    EnterExpressionEvaluationContext Unevaluated(S, Sema::ConstantEvaluated);
69    ExprResult Result = S.SubstExpr(Aligned->getAlignmentExpr(), TemplateArgs);
70    if (!Result.isInvalid())
71      S.AddAlignedAttr(Aligned->getLocation(), New, Result.takeAs<Expr>(),
72                       Aligned->getSpellingListIndex(), IsPackExpansion);
73  } else {
74    TypeSourceInfo *Result = S.SubstType(Aligned->getAlignmentType(),
75                                         TemplateArgs, Aligned->getLocation(),
76                                         DeclarationName());
77    if (Result)
78      S.AddAlignedAttr(Aligned->getLocation(), New, Result,
79                       Aligned->getSpellingListIndex(), IsPackExpansion);
80  }
81}
82
83static void instantiateDependentAlignedAttr(
84    Sema &S, const MultiLevelTemplateArgumentList &TemplateArgs,
85    const AlignedAttr *Aligned, Decl *New) {
86  if (!Aligned->isPackExpansion()) {
87    instantiateDependentAlignedAttr(S, TemplateArgs, Aligned, New, false);
88    return;
89  }
90
91  SmallVector<UnexpandedParameterPack, 2> Unexpanded;
92  if (Aligned->isAlignmentExpr())
93    S.collectUnexpandedParameterPacks(Aligned->getAlignmentExpr(),
94                                      Unexpanded);
95  else
96    S.collectUnexpandedParameterPacks(Aligned->getAlignmentType()->getTypeLoc(),
97                                      Unexpanded);
98  assert(!Unexpanded.empty() && "Pack expansion without parameter packs?");
99
100  // Determine whether we can expand this attribute pack yet.
101  bool Expand = true, RetainExpansion = false;
102  Optional<unsigned> NumExpansions;
103  // FIXME: Use the actual location of the ellipsis.
104  SourceLocation EllipsisLoc = Aligned->getLocation();
105  if (S.CheckParameterPacksForExpansion(EllipsisLoc, Aligned->getRange(),
106                                        Unexpanded, TemplateArgs, Expand,
107                                        RetainExpansion, NumExpansions))
108    return;
109
110  if (!Expand) {
111    Sema::ArgumentPackSubstitutionIndexRAII SubstIndex(S, -1);
112    instantiateDependentAlignedAttr(S, TemplateArgs, Aligned, New, true);
113  } else {
114    for (unsigned I = 0; I != *NumExpansions; ++I) {
115      Sema::ArgumentPackSubstitutionIndexRAII SubstIndex(S, I);
116      instantiateDependentAlignedAttr(S, TemplateArgs, Aligned, New, false);
117    }
118  }
119}
120
121void Sema::InstantiateAttrs(const MultiLevelTemplateArgumentList &TemplateArgs,
122                            const Decl *Tmpl, Decl *New,
123                            LateInstantiatedAttrVec *LateAttrs,
124                            LocalInstantiationScope *OuterMostScope) {
125  for (AttrVec::const_iterator i = Tmpl->attr_begin(), e = Tmpl->attr_end();
126       i != e; ++i) {
127    const Attr *TmplAttr = *i;
128
129    // FIXME: This should be generalized to more than just the AlignedAttr.
130    const AlignedAttr *Aligned = dyn_cast<AlignedAttr>(TmplAttr);
131    if (Aligned && Aligned->isAlignmentDependent()) {
132      instantiateDependentAlignedAttr(*this, TemplateArgs, Aligned, New);
133      continue;
134    }
135
136    assert(!TmplAttr->isPackExpansion());
137    if (TmplAttr->isLateParsed() && LateAttrs) {
138      // Late parsed attributes must be instantiated and attached after the
139      // enclosing class has been instantiated.  See Sema::InstantiateClass.
140      LocalInstantiationScope *Saved = 0;
141      if (CurrentInstantiationScope)
142        Saved = CurrentInstantiationScope->cloneScopes(OuterMostScope);
143      LateAttrs->push_back(LateInstantiatedAttribute(TmplAttr, Saved, New));
144    } else {
145      Attr *NewAttr = sema::instantiateTemplateAttribute(TmplAttr, Context,
146                                                         *this, TemplateArgs);
147      if (NewAttr)
148        New->addAttr(NewAttr);
149    }
150  }
151}
152
153Decl *
154TemplateDeclInstantiator::VisitTranslationUnitDecl(TranslationUnitDecl *D) {
155  llvm_unreachable("Translation units cannot be instantiated");
156}
157
158Decl *
159TemplateDeclInstantiator::VisitLabelDecl(LabelDecl *D) {
160  LabelDecl *Inst = LabelDecl::Create(SemaRef.Context, Owner, D->getLocation(),
161                                      D->getIdentifier());
162  Owner->addDecl(Inst);
163  return Inst;
164}
165
166Decl *
167TemplateDeclInstantiator::VisitNamespaceDecl(NamespaceDecl *D) {
168  llvm_unreachable("Namespaces cannot be instantiated");
169}
170
171Decl *
172TemplateDeclInstantiator::VisitNamespaceAliasDecl(NamespaceAliasDecl *D) {
173  NamespaceAliasDecl *Inst
174    = NamespaceAliasDecl::Create(SemaRef.Context, Owner,
175                                 D->getNamespaceLoc(),
176                                 D->getAliasLoc(),
177                                 D->getIdentifier(),
178                                 D->getQualifierLoc(),
179                                 D->getTargetNameLoc(),
180                                 D->getNamespace());
181  Owner->addDecl(Inst);
182  return Inst;
183}
184
185Decl *TemplateDeclInstantiator::InstantiateTypedefNameDecl(TypedefNameDecl *D,
186                                                           bool IsTypeAlias) {
187  bool Invalid = false;
188  TypeSourceInfo *DI = D->getTypeSourceInfo();
189  if (DI->getType()->isInstantiationDependentType() ||
190      DI->getType()->isVariablyModifiedType()) {
191    DI = SemaRef.SubstType(DI, TemplateArgs,
192                           D->getLocation(), D->getDeclName());
193    if (!DI) {
194      Invalid = true;
195      DI = SemaRef.Context.getTrivialTypeSourceInfo(SemaRef.Context.IntTy);
196    }
197  } else {
198    SemaRef.MarkDeclarationsReferencedInType(D->getLocation(), DI->getType());
199  }
200
201  // HACK: g++ has a bug where it gets the value kind of ?: wrong.
202  // libstdc++ relies upon this bug in its implementation of common_type.
203  // If we happen to be processing that implementation, fake up the g++ ?:
204  // semantics. See LWG issue 2141 for more information on the bug.
205  const DecltypeType *DT = DI->getType()->getAs<DecltypeType>();
206  CXXRecordDecl *RD = dyn_cast<CXXRecordDecl>(D->getDeclContext());
207  if (DT && RD && isa<ConditionalOperator>(DT->getUnderlyingExpr()) &&
208      DT->isReferenceType() &&
209      RD->getEnclosingNamespaceContext() == SemaRef.getStdNamespace() &&
210      RD->getIdentifier() && RD->getIdentifier()->isStr("common_type") &&
211      D->getIdentifier() && D->getIdentifier()->isStr("type") &&
212      SemaRef.getSourceManager().isInSystemHeader(D->getLocStart()))
213    // Fold it to the (non-reference) type which g++ would have produced.
214    DI = SemaRef.Context.getTrivialTypeSourceInfo(
215      DI->getType().getNonReferenceType());
216
217  // Create the new typedef
218  TypedefNameDecl *Typedef;
219  if (IsTypeAlias)
220    Typedef = TypeAliasDecl::Create(SemaRef.Context, Owner, D->getLocStart(),
221                                    D->getLocation(), D->getIdentifier(), DI);
222  else
223    Typedef = TypedefDecl::Create(SemaRef.Context, Owner, D->getLocStart(),
224                                  D->getLocation(), D->getIdentifier(), DI);
225  if (Invalid)
226    Typedef->setInvalidDecl();
227
228  // If the old typedef was the name for linkage purposes of an anonymous
229  // tag decl, re-establish that relationship for the new typedef.
230  if (const TagType *oldTagType = D->getUnderlyingType()->getAs<TagType>()) {
231    TagDecl *oldTag = oldTagType->getDecl();
232    if (oldTag->getTypedefNameForAnonDecl() == D && !Invalid) {
233      TagDecl *newTag = DI->getType()->castAs<TagType>()->getDecl();
234      assert(!newTag->hasNameForLinkage());
235      newTag->setTypedefNameForAnonDecl(Typedef);
236    }
237  }
238
239  if (TypedefNameDecl *Prev = D->getPreviousDecl()) {
240    NamedDecl *InstPrev = SemaRef.FindInstantiatedDecl(D->getLocation(), Prev,
241                                                       TemplateArgs);
242    if (!InstPrev)
243      return 0;
244
245    TypedefNameDecl *InstPrevTypedef = cast<TypedefNameDecl>(InstPrev);
246
247    // If the typedef types are not identical, reject them.
248    SemaRef.isIncompatibleTypedef(InstPrevTypedef, Typedef);
249
250    Typedef->setPreviousDeclaration(InstPrevTypedef);
251  }
252
253  SemaRef.InstantiateAttrs(TemplateArgs, D, Typedef);
254
255  Typedef->setAccess(D->getAccess());
256
257  return Typedef;
258}
259
260Decl *TemplateDeclInstantiator::VisitTypedefDecl(TypedefDecl *D) {
261  Decl *Typedef = InstantiateTypedefNameDecl(D, /*IsTypeAlias=*/false);
262  Owner->addDecl(Typedef);
263  return Typedef;
264}
265
266Decl *TemplateDeclInstantiator::VisitTypeAliasDecl(TypeAliasDecl *D) {
267  Decl *Typedef = InstantiateTypedefNameDecl(D, /*IsTypeAlias=*/true);
268  Owner->addDecl(Typedef);
269  return Typedef;
270}
271
272Decl *
273TemplateDeclInstantiator::VisitTypeAliasTemplateDecl(TypeAliasTemplateDecl *D) {
274  // Create a local instantiation scope for this type alias template, which
275  // will contain the instantiations of the template parameters.
276  LocalInstantiationScope Scope(SemaRef);
277
278  TemplateParameterList *TempParams = D->getTemplateParameters();
279  TemplateParameterList *InstParams = SubstTemplateParams(TempParams);
280  if (!InstParams)
281    return 0;
282
283  TypeAliasDecl *Pattern = D->getTemplatedDecl();
284
285  TypeAliasTemplateDecl *PrevAliasTemplate = 0;
286  if (Pattern->getPreviousDecl()) {
287    DeclContext::lookup_result Found = Owner->lookup(Pattern->getDeclName());
288    if (!Found.empty()) {
289      PrevAliasTemplate = dyn_cast<TypeAliasTemplateDecl>(Found.front());
290    }
291  }
292
293  TypeAliasDecl *AliasInst = cast_or_null<TypeAliasDecl>(
294    InstantiateTypedefNameDecl(Pattern, /*IsTypeAlias=*/true));
295  if (!AliasInst)
296    return 0;
297
298  TypeAliasTemplateDecl *Inst
299    = TypeAliasTemplateDecl::Create(SemaRef.Context, Owner, D->getLocation(),
300                                    D->getDeclName(), InstParams, AliasInst);
301  if (PrevAliasTemplate)
302    Inst->setPreviousDeclaration(PrevAliasTemplate);
303
304  Inst->setAccess(D->getAccess());
305
306  if (!PrevAliasTemplate)
307    Inst->setInstantiatedFromMemberTemplate(D);
308
309  Owner->addDecl(Inst);
310
311  return Inst;
312}
313
314Decl *TemplateDeclInstantiator::VisitVarDecl(VarDecl *D) {
315  // If this is the variable for an anonymous struct or union,
316  // instantiate the anonymous struct/union type first.
317  if (const RecordType *RecordTy = D->getType()->getAs<RecordType>())
318    if (RecordTy->getDecl()->isAnonymousStructOrUnion())
319      if (!VisitCXXRecordDecl(cast<CXXRecordDecl>(RecordTy->getDecl())))
320        return 0;
321
322  // Do substitution on the type of the declaration
323  TypeSourceInfo *DI = SemaRef.SubstType(D->getTypeSourceInfo(),
324                                         TemplateArgs,
325                                         D->getTypeSpecStartLoc(),
326                                         D->getDeclName());
327  if (!DI)
328    return 0;
329
330  if (DI->getType()->isFunctionType()) {
331    SemaRef.Diag(D->getLocation(), diag::err_variable_instantiates_to_function)
332      << D->isStaticDataMember() << DI->getType();
333    return 0;
334  }
335
336  // Build the instantiated declaration
337  VarDecl *Var = VarDecl::Create(SemaRef.Context, Owner,
338                                 D->getInnerLocStart(),
339                                 D->getLocation(), D->getIdentifier(),
340                                 DI->getType(), DI,
341                                 D->getStorageClass(),
342                                 D->getStorageClassAsWritten());
343  Var->setThreadSpecified(D->isThreadSpecified());
344  Var->setInitStyle(D->getInitStyle());
345  Var->setCXXForRangeDecl(D->isCXXForRangeDecl());
346  Var->setConstexpr(D->isConstexpr());
347
348  // Substitute the nested name specifier, if any.
349  if (SubstQualifier(D, Var))
350    return 0;
351
352  // If we are instantiating a static data member defined
353  // out-of-line, the instantiation will have the same lexical
354  // context (which will be a namespace scope) as the template.
355  if (D->isOutOfLine())
356    Var->setLexicalDeclContext(D->getLexicalDeclContext());
357
358  Var->setAccess(D->getAccess());
359
360  if (!D->isStaticDataMember()) {
361    Var->setUsed(D->isUsed(false));
362    Var->setReferenced(D->isReferenced());
363  }
364
365  SemaRef.InstantiateAttrs(TemplateArgs, D, Var, LateAttrs, StartingScope);
366
367  if (Var->hasAttrs())
368    SemaRef.CheckAlignasUnderalignment(Var);
369
370  // FIXME: In theory, we could have a previous declaration for variables that
371  // are not static data members.
372  // FIXME: having to fake up a LookupResult is dumb.
373  LookupResult Previous(SemaRef, Var->getDeclName(), Var->getLocation(),
374                        Sema::LookupOrdinaryName, Sema::ForRedeclaration);
375  if (D->isStaticDataMember())
376    SemaRef.LookupQualifiedName(Previous, Owner, false);
377
378  // In ARC, infer 'retaining' for variables of retainable type.
379  if (SemaRef.getLangOpts().ObjCAutoRefCount &&
380      SemaRef.inferObjCARCLifetime(Var))
381    Var->setInvalidDecl();
382
383  SemaRef.CheckVariableDeclaration(Var, Previous);
384
385  if (D->isOutOfLine()) {
386    D->getLexicalDeclContext()->addDecl(Var);
387    Owner->makeDeclVisibleInContext(Var);
388  } else {
389    Owner->addDecl(Var);
390    if (Owner->isFunctionOrMethod())
391      SemaRef.CurrentInstantiationScope->InstantiatedLocal(D, Var);
392  }
393
394  // Link instantiations of static data members back to the template from
395  // which they were instantiated.
396  if (Var->isStaticDataMember())
397    SemaRef.Context.setInstantiatedFromStaticDataMember(Var, D,
398                                                     TSK_ImplicitInstantiation);
399
400  if (Var->getAnyInitializer()) {
401    // We already have an initializer in the class.
402  } else if (D->getInit()) {
403    if (Var->isStaticDataMember() && !D->isOutOfLine())
404      SemaRef.PushExpressionEvaluationContext(Sema::ConstantEvaluated, D);
405    else
406      SemaRef.PushExpressionEvaluationContext(Sema::PotentiallyEvaluated, D);
407
408    // Instantiate the initializer.
409    ExprResult Init = SemaRef.SubstInitializer(D->getInit(), TemplateArgs,
410                                        D->getInitStyle() == VarDecl::CallInit);
411    if (!Init.isInvalid()) {
412      bool TypeMayContainAuto = true;
413      if (Init.get()) {
414        bool DirectInit = D->isDirectInit();
415        SemaRef.AddInitializerToDecl(Var, Init.take(), DirectInit,
416                                     TypeMayContainAuto);
417      } else
418        SemaRef.ActOnUninitializedDecl(Var, TypeMayContainAuto);
419    } else {
420      // FIXME: Not too happy about invalidating the declaration
421      // because of a bogus initializer.
422      Var->setInvalidDecl();
423    }
424
425    SemaRef.PopExpressionEvaluationContext();
426  } else if ((!Var->isStaticDataMember() || Var->isOutOfLine()) &&
427             !Var->isCXXForRangeDecl())
428    SemaRef.ActOnUninitializedDecl(Var, false);
429
430  // Diagnose unused local variables with dependent types, where the diagnostic
431  // will have been deferred.
432  if (!Var->isInvalidDecl() && Owner->isFunctionOrMethod() && !Var->isUsed() &&
433      D->getType()->isDependentType())
434    SemaRef.DiagnoseUnusedDecl(Var);
435
436  return Var;
437}
438
439Decl *TemplateDeclInstantiator::VisitAccessSpecDecl(AccessSpecDecl *D) {
440  AccessSpecDecl* AD
441    = AccessSpecDecl::Create(SemaRef.Context, D->getAccess(), Owner,
442                             D->getAccessSpecifierLoc(), D->getColonLoc());
443  Owner->addHiddenDecl(AD);
444  return AD;
445}
446
447Decl *TemplateDeclInstantiator::VisitFieldDecl(FieldDecl *D) {
448  bool Invalid = false;
449  TypeSourceInfo *DI = D->getTypeSourceInfo();
450  if (DI->getType()->isInstantiationDependentType() ||
451      DI->getType()->isVariablyModifiedType())  {
452    DI = SemaRef.SubstType(DI, TemplateArgs,
453                           D->getLocation(), D->getDeclName());
454    if (!DI) {
455      DI = D->getTypeSourceInfo();
456      Invalid = true;
457    } else if (DI->getType()->isFunctionType()) {
458      // C++ [temp.arg.type]p3:
459      //   If a declaration acquires a function type through a type
460      //   dependent on a template-parameter and this causes a
461      //   declaration that does not use the syntactic form of a
462      //   function declarator to have function type, the program is
463      //   ill-formed.
464      SemaRef.Diag(D->getLocation(), diag::err_field_instantiates_to_function)
465        << DI->getType();
466      Invalid = true;
467    }
468  } else {
469    SemaRef.MarkDeclarationsReferencedInType(D->getLocation(), DI->getType());
470  }
471
472  Expr *BitWidth = D->getBitWidth();
473  if (Invalid)
474    BitWidth = 0;
475  else if (BitWidth) {
476    // The bit-width expression is a constant expression.
477    EnterExpressionEvaluationContext Unevaluated(SemaRef,
478                                                 Sema::ConstantEvaluated);
479
480    ExprResult InstantiatedBitWidth
481      = SemaRef.SubstExpr(BitWidth, TemplateArgs);
482    if (InstantiatedBitWidth.isInvalid()) {
483      Invalid = true;
484      BitWidth = 0;
485    } else
486      BitWidth = InstantiatedBitWidth.takeAs<Expr>();
487  }
488
489  FieldDecl *Field = SemaRef.CheckFieldDecl(D->getDeclName(),
490                                            DI->getType(), DI,
491                                            cast<RecordDecl>(Owner),
492                                            D->getLocation(),
493                                            D->isMutable(),
494                                            BitWidth,
495                                            D->getInClassInitStyle(),
496                                            D->getInnerLocStart(),
497                                            D->getAccess(),
498                                            0);
499  if (!Field) {
500    cast<Decl>(Owner)->setInvalidDecl();
501    return 0;
502  }
503
504  SemaRef.InstantiateAttrs(TemplateArgs, D, Field, LateAttrs, StartingScope);
505
506  if (Field->hasAttrs())
507    SemaRef.CheckAlignasUnderalignment(Field);
508
509  if (Invalid)
510    Field->setInvalidDecl();
511
512  if (!Field->getDeclName()) {
513    // Keep track of where this decl came from.
514    SemaRef.Context.setInstantiatedFromUnnamedFieldDecl(Field, D);
515  }
516  if (CXXRecordDecl *Parent= dyn_cast<CXXRecordDecl>(Field->getDeclContext())) {
517    if (Parent->isAnonymousStructOrUnion() &&
518        Parent->getRedeclContext()->isFunctionOrMethod())
519      SemaRef.CurrentInstantiationScope->InstantiatedLocal(D, Field);
520  }
521
522  Field->setImplicit(D->isImplicit());
523  Field->setAccess(D->getAccess());
524  Owner->addDecl(Field);
525
526  return Field;
527}
528
529Decl *TemplateDeclInstantiator::VisitIndirectFieldDecl(IndirectFieldDecl *D) {
530  NamedDecl **NamedChain =
531    new (SemaRef.Context)NamedDecl*[D->getChainingSize()];
532
533  int i = 0;
534  for (IndirectFieldDecl::chain_iterator PI =
535       D->chain_begin(), PE = D->chain_end();
536       PI != PE; ++PI) {
537    NamedDecl *Next = SemaRef.FindInstantiatedDecl(D->getLocation(), *PI,
538                                              TemplateArgs);
539    if (!Next)
540      return 0;
541
542    NamedChain[i++] = Next;
543  }
544
545  QualType T = cast<FieldDecl>(NamedChain[i-1])->getType();
546  IndirectFieldDecl* IndirectField
547    = IndirectFieldDecl::Create(SemaRef.Context, Owner, D->getLocation(),
548                                D->getIdentifier(), T,
549                                NamedChain, D->getChainingSize());
550
551
552  IndirectField->setImplicit(D->isImplicit());
553  IndirectField->setAccess(D->getAccess());
554  Owner->addDecl(IndirectField);
555  return IndirectField;
556}
557
558Decl *TemplateDeclInstantiator::VisitFriendDecl(FriendDecl *D) {
559  // Handle friend type expressions by simply substituting template
560  // parameters into the pattern type and checking the result.
561  if (TypeSourceInfo *Ty = D->getFriendType()) {
562    TypeSourceInfo *InstTy;
563    // If this is an unsupported friend, don't bother substituting template
564    // arguments into it. The actual type referred to won't be used by any
565    // parts of Clang, and may not be valid for instantiating. Just use the
566    // same info for the instantiated friend.
567    if (D->isUnsupportedFriend()) {
568      InstTy = Ty;
569    } else {
570      InstTy = SemaRef.SubstType(Ty, TemplateArgs,
571                                 D->getLocation(), DeclarationName());
572    }
573    if (!InstTy)
574      return 0;
575
576    FriendDecl *FD = SemaRef.CheckFriendTypeDecl(D->getLocStart(),
577                                                 D->getFriendLoc(), InstTy);
578    if (!FD)
579      return 0;
580
581    FD->setAccess(AS_public);
582    FD->setUnsupportedFriend(D->isUnsupportedFriend());
583    Owner->addDecl(FD);
584    return FD;
585  }
586
587  NamedDecl *ND = D->getFriendDecl();
588  assert(ND && "friend decl must be a decl or a type!");
589
590  // All of the Visit implementations for the various potential friend
591  // declarations have to be carefully written to work for friend
592  // objects, with the most important detail being that the target
593  // decl should almost certainly not be placed in Owner.
594  Decl *NewND = Visit(ND);
595  if (!NewND) return 0;
596
597  FriendDecl *FD =
598    FriendDecl::Create(SemaRef.Context, Owner, D->getLocation(),
599                       cast<NamedDecl>(NewND), D->getFriendLoc());
600  FD->setAccess(AS_public);
601  FD->setUnsupportedFriend(D->isUnsupportedFriend());
602  Owner->addDecl(FD);
603  return FD;
604}
605
606Decl *TemplateDeclInstantiator::VisitStaticAssertDecl(StaticAssertDecl *D) {
607  Expr *AssertExpr = D->getAssertExpr();
608
609  // The expression in a static assertion is a constant expression.
610  EnterExpressionEvaluationContext Unevaluated(SemaRef,
611                                               Sema::ConstantEvaluated);
612
613  ExprResult InstantiatedAssertExpr
614    = SemaRef.SubstExpr(AssertExpr, TemplateArgs);
615  if (InstantiatedAssertExpr.isInvalid())
616    return 0;
617
618  return SemaRef.BuildStaticAssertDeclaration(D->getLocation(),
619                                              InstantiatedAssertExpr.get(),
620                                              D->getMessage(),
621                                              D->getRParenLoc(),
622                                              D->isFailed());
623}
624
625Decl *TemplateDeclInstantiator::VisitEnumDecl(EnumDecl *D) {
626  EnumDecl *PrevDecl = 0;
627  if (D->getPreviousDecl()) {
628    NamedDecl *Prev = SemaRef.FindInstantiatedDecl(D->getLocation(),
629                                                   D->getPreviousDecl(),
630                                                   TemplateArgs);
631    if (!Prev) return 0;
632    PrevDecl = cast<EnumDecl>(Prev);
633  }
634
635  EnumDecl *Enum = EnumDecl::Create(SemaRef.Context, Owner, D->getLocStart(),
636                                    D->getLocation(), D->getIdentifier(),
637                                    PrevDecl, D->isScoped(),
638                                    D->isScopedUsingClassTag(), D->isFixed());
639  if (D->isFixed()) {
640    if (TypeSourceInfo *TI = D->getIntegerTypeSourceInfo()) {
641      // If we have type source information for the underlying type, it means it
642      // has been explicitly set by the user. Perform substitution on it before
643      // moving on.
644      SourceLocation UnderlyingLoc = TI->getTypeLoc().getBeginLoc();
645      TypeSourceInfo *NewTI = SemaRef.SubstType(TI, TemplateArgs, UnderlyingLoc,
646                                                DeclarationName());
647      if (!NewTI || SemaRef.CheckEnumUnderlyingType(NewTI))
648        Enum->setIntegerType(SemaRef.Context.IntTy);
649      else
650        Enum->setIntegerTypeSourceInfo(NewTI);
651    } else {
652      assert(!D->getIntegerType()->isDependentType()
653             && "Dependent type without type source info");
654      Enum->setIntegerType(D->getIntegerType());
655    }
656  }
657
658  SemaRef.InstantiateAttrs(TemplateArgs, D, Enum);
659
660  Enum->setInstantiationOfMemberEnum(D, TSK_ImplicitInstantiation);
661  Enum->setAccess(D->getAccess());
662  if (SubstQualifier(D, Enum)) return 0;
663  Owner->addDecl(Enum);
664
665  EnumDecl *Def = D->getDefinition();
666  if (Def && Def != D) {
667    // If this is an out-of-line definition of an enum member template, check
668    // that the underlying types match in the instantiation of both
669    // declarations.
670    if (TypeSourceInfo *TI = Def->getIntegerTypeSourceInfo()) {
671      SourceLocation UnderlyingLoc = TI->getTypeLoc().getBeginLoc();
672      QualType DefnUnderlying =
673        SemaRef.SubstType(TI->getType(), TemplateArgs,
674                          UnderlyingLoc, DeclarationName());
675      SemaRef.CheckEnumRedeclaration(Def->getLocation(), Def->isScoped(),
676                                     DefnUnderlying, Enum);
677    }
678  }
679
680  if (D->getDeclContext()->isFunctionOrMethod())
681    SemaRef.CurrentInstantiationScope->InstantiatedLocal(D, Enum);
682
683  // C++11 [temp.inst]p1: The implicit instantiation of a class template
684  // specialization causes the implicit instantiation of the declarations, but
685  // not the definitions of scoped member enumerations.
686  // FIXME: There appears to be no wording for what happens for an enum defined
687  // within a block scope, but we treat that much like a member template. Only
688  // instantiate the definition when visiting the definition in that case, since
689  // we will visit all redeclarations.
690  if (!Enum->isScoped() && Def &&
691      (!D->getDeclContext()->isFunctionOrMethod() || D->isCompleteDefinition()))
692    InstantiateEnumDefinition(Enum, Def);
693
694  return Enum;
695}
696
697void TemplateDeclInstantiator::InstantiateEnumDefinition(
698    EnumDecl *Enum, EnumDecl *Pattern) {
699  Enum->startDefinition();
700
701  // Update the location to refer to the definition.
702  Enum->setLocation(Pattern->getLocation());
703
704  SmallVector<Decl*, 4> Enumerators;
705
706  EnumConstantDecl *LastEnumConst = 0;
707  for (EnumDecl::enumerator_iterator EC = Pattern->enumerator_begin(),
708         ECEnd = Pattern->enumerator_end();
709       EC != ECEnd; ++EC) {
710    // The specified value for the enumerator.
711    ExprResult Value = SemaRef.Owned((Expr *)0);
712    if (Expr *UninstValue = EC->getInitExpr()) {
713      // The enumerator's value expression is a constant expression.
714      EnterExpressionEvaluationContext Unevaluated(SemaRef,
715                                                   Sema::ConstantEvaluated);
716
717      Value = SemaRef.SubstExpr(UninstValue, TemplateArgs);
718    }
719
720    // Drop the initial value and continue.
721    bool isInvalid = false;
722    if (Value.isInvalid()) {
723      Value = SemaRef.Owned((Expr *)0);
724      isInvalid = true;
725    }
726
727    EnumConstantDecl *EnumConst
728      = SemaRef.CheckEnumConstant(Enum, LastEnumConst,
729                                  EC->getLocation(), EC->getIdentifier(),
730                                  Value.get());
731
732    if (isInvalid) {
733      if (EnumConst)
734        EnumConst->setInvalidDecl();
735      Enum->setInvalidDecl();
736    }
737
738    if (EnumConst) {
739      SemaRef.InstantiateAttrs(TemplateArgs, *EC, EnumConst);
740
741      EnumConst->setAccess(Enum->getAccess());
742      Enum->addDecl(EnumConst);
743      Enumerators.push_back(EnumConst);
744      LastEnumConst = EnumConst;
745
746      if (Pattern->getDeclContext()->isFunctionOrMethod() &&
747          !Enum->isScoped()) {
748        // If the enumeration is within a function or method, record the enum
749        // constant as a local.
750        SemaRef.CurrentInstantiationScope->InstantiatedLocal(*EC, EnumConst);
751      }
752    }
753  }
754
755  // FIXME: Fixup LBraceLoc
756  SemaRef.ActOnEnumBody(Enum->getLocation(), SourceLocation(),
757                        Enum->getRBraceLoc(), Enum,
758                        Enumerators.data(), Enumerators.size(),
759                        0, 0);
760}
761
762Decl *TemplateDeclInstantiator::VisitEnumConstantDecl(EnumConstantDecl *D) {
763  llvm_unreachable("EnumConstantDecls can only occur within EnumDecls.");
764}
765
766Decl *TemplateDeclInstantiator::VisitClassTemplateDecl(ClassTemplateDecl *D) {
767  bool isFriend = (D->getFriendObjectKind() != Decl::FOK_None);
768
769  // Create a local instantiation scope for this class template, which
770  // will contain the instantiations of the template parameters.
771  LocalInstantiationScope Scope(SemaRef);
772  TemplateParameterList *TempParams = D->getTemplateParameters();
773  TemplateParameterList *InstParams = SubstTemplateParams(TempParams);
774  if (!InstParams)
775    return NULL;
776
777  CXXRecordDecl *Pattern = D->getTemplatedDecl();
778
779  // Instantiate the qualifier.  We have to do this first in case
780  // we're a friend declaration, because if we are then we need to put
781  // the new declaration in the appropriate context.
782  NestedNameSpecifierLoc QualifierLoc = Pattern->getQualifierLoc();
783  if (QualifierLoc) {
784    QualifierLoc = SemaRef.SubstNestedNameSpecifierLoc(QualifierLoc,
785                                                       TemplateArgs);
786    if (!QualifierLoc)
787      return 0;
788  }
789
790  CXXRecordDecl *PrevDecl = 0;
791  ClassTemplateDecl *PrevClassTemplate = 0;
792
793  if (!isFriend && Pattern->getPreviousDecl()) {
794    DeclContext::lookup_result Found = Owner->lookup(Pattern->getDeclName());
795    if (!Found.empty()) {
796      PrevClassTemplate = dyn_cast<ClassTemplateDecl>(Found.front());
797      if (PrevClassTemplate)
798        PrevDecl = PrevClassTemplate->getTemplatedDecl();
799    }
800  }
801
802  // If this isn't a friend, then it's a member template, in which
803  // case we just want to build the instantiation in the
804  // specialization.  If it is a friend, we want to build it in
805  // the appropriate context.
806  DeclContext *DC = Owner;
807  if (isFriend) {
808    if (QualifierLoc) {
809      CXXScopeSpec SS;
810      SS.Adopt(QualifierLoc);
811      DC = SemaRef.computeDeclContext(SS);
812      if (!DC) return 0;
813    } else {
814      DC = SemaRef.FindInstantiatedContext(Pattern->getLocation(),
815                                           Pattern->getDeclContext(),
816                                           TemplateArgs);
817    }
818
819    // Look for a previous declaration of the template in the owning
820    // context.
821    LookupResult R(SemaRef, Pattern->getDeclName(), Pattern->getLocation(),
822                   Sema::LookupOrdinaryName, Sema::ForRedeclaration);
823    SemaRef.LookupQualifiedName(R, DC);
824
825    if (R.isSingleResult()) {
826      PrevClassTemplate = R.getAsSingle<ClassTemplateDecl>();
827      if (PrevClassTemplate)
828        PrevDecl = PrevClassTemplate->getTemplatedDecl();
829    }
830
831    if (!PrevClassTemplate && QualifierLoc) {
832      SemaRef.Diag(Pattern->getLocation(), diag::err_not_tag_in_scope)
833        << D->getTemplatedDecl()->getTagKind() << Pattern->getDeclName() << DC
834        << QualifierLoc.getSourceRange();
835      return 0;
836    }
837
838    bool AdoptedPreviousTemplateParams = false;
839    if (PrevClassTemplate) {
840      bool Complain = true;
841
842      // HACK: libstdc++ 4.2.1 contains an ill-formed friend class
843      // template for struct std::tr1::__detail::_Map_base, where the
844      // template parameters of the friend declaration don't match the
845      // template parameters of the original declaration. In this one
846      // case, we don't complain about the ill-formed friend
847      // declaration.
848      if (isFriend && Pattern->getIdentifier() &&
849          Pattern->getIdentifier()->isStr("_Map_base") &&
850          DC->isNamespace() &&
851          cast<NamespaceDecl>(DC)->getIdentifier() &&
852          cast<NamespaceDecl>(DC)->getIdentifier()->isStr("__detail")) {
853        DeclContext *DCParent = DC->getParent();
854        if (DCParent->isNamespace() &&
855            cast<NamespaceDecl>(DCParent)->getIdentifier() &&
856            cast<NamespaceDecl>(DCParent)->getIdentifier()->isStr("tr1")) {
857          DeclContext *DCParent2 = DCParent->getParent();
858          if (DCParent2->isNamespace() &&
859              cast<NamespaceDecl>(DCParent2)->getIdentifier() &&
860              cast<NamespaceDecl>(DCParent2)->getIdentifier()->isStr("std") &&
861              DCParent2->getParent()->isTranslationUnit())
862            Complain = false;
863        }
864      }
865
866      TemplateParameterList *PrevParams
867        = PrevClassTemplate->getTemplateParameters();
868
869      // Make sure the parameter lists match.
870      if (!SemaRef.TemplateParameterListsAreEqual(InstParams, PrevParams,
871                                                  Complain,
872                                                  Sema::TPL_TemplateMatch)) {
873        if (Complain)
874          return 0;
875
876        AdoptedPreviousTemplateParams = true;
877        InstParams = PrevParams;
878      }
879
880      // Do some additional validation, then merge default arguments
881      // from the existing declarations.
882      if (!AdoptedPreviousTemplateParams &&
883          SemaRef.CheckTemplateParameterList(InstParams, PrevParams,
884                                             Sema::TPC_ClassTemplate))
885        return 0;
886    }
887  }
888
889  CXXRecordDecl *RecordInst
890    = CXXRecordDecl::Create(SemaRef.Context, Pattern->getTagKind(), DC,
891                            Pattern->getLocStart(), Pattern->getLocation(),
892                            Pattern->getIdentifier(), PrevDecl,
893                            /*DelayTypeCreation=*/true);
894
895  if (QualifierLoc)
896    RecordInst->setQualifierInfo(QualifierLoc);
897
898  ClassTemplateDecl *Inst
899    = ClassTemplateDecl::Create(SemaRef.Context, DC, D->getLocation(),
900                                D->getIdentifier(), InstParams, RecordInst,
901                                PrevClassTemplate);
902  RecordInst->setDescribedClassTemplate(Inst);
903
904  if (isFriend) {
905    if (PrevClassTemplate)
906      Inst->setAccess(PrevClassTemplate->getAccess());
907    else
908      Inst->setAccess(D->getAccess());
909
910    Inst->setObjectOfFriendDecl(PrevClassTemplate != 0);
911    // TODO: do we want to track the instantiation progeny of this
912    // friend target decl?
913  } else {
914    Inst->setAccess(D->getAccess());
915    if (!PrevClassTemplate)
916      Inst->setInstantiatedFromMemberTemplate(D);
917  }
918
919  // Trigger creation of the type for the instantiation.
920  SemaRef.Context.getInjectedClassNameType(RecordInst,
921                                    Inst->getInjectedClassNameSpecialization());
922
923  // Finish handling of friends.
924  if (isFriend) {
925    DC->makeDeclVisibleInContext(Inst);
926    Inst->setLexicalDeclContext(Owner);
927    RecordInst->setLexicalDeclContext(Owner);
928    return Inst;
929  }
930
931  if (D->isOutOfLine()) {
932    Inst->setLexicalDeclContext(D->getLexicalDeclContext());
933    RecordInst->setLexicalDeclContext(D->getLexicalDeclContext());
934  }
935
936  Owner->addDecl(Inst);
937
938  if (!PrevClassTemplate) {
939    // Queue up any out-of-line partial specializations of this member
940    // class template; the client will force their instantiation once
941    // the enclosing class has been instantiated.
942    SmallVector<ClassTemplatePartialSpecializationDecl *, 4> PartialSpecs;
943    D->getPartialSpecializations(PartialSpecs);
944    for (unsigned I = 0, N = PartialSpecs.size(); I != N; ++I)
945      if (PartialSpecs[I]->isOutOfLine())
946        OutOfLinePartialSpecs.push_back(std::make_pair(Inst, PartialSpecs[I]));
947  }
948
949  return Inst;
950}
951
952Decl *
953TemplateDeclInstantiator::VisitClassTemplatePartialSpecializationDecl(
954                                   ClassTemplatePartialSpecializationDecl *D) {
955  ClassTemplateDecl *ClassTemplate = D->getSpecializedTemplate();
956
957  // Lookup the already-instantiated declaration in the instantiation
958  // of the class template and return that.
959  DeclContext::lookup_result Found
960    = Owner->lookup(ClassTemplate->getDeclName());
961  if (Found.empty())
962    return 0;
963
964  ClassTemplateDecl *InstClassTemplate
965    = dyn_cast<ClassTemplateDecl>(Found.front());
966  if (!InstClassTemplate)
967    return 0;
968
969  if (ClassTemplatePartialSpecializationDecl *Result
970        = InstClassTemplate->findPartialSpecInstantiatedFromMember(D))
971    return Result;
972
973  return InstantiateClassTemplatePartialSpecialization(InstClassTemplate, D);
974}
975
976Decl *
977TemplateDeclInstantiator::VisitFunctionTemplateDecl(FunctionTemplateDecl *D) {
978  // Create a local instantiation scope for this function template, which
979  // will contain the instantiations of the template parameters and then get
980  // merged with the local instantiation scope for the function template
981  // itself.
982  LocalInstantiationScope Scope(SemaRef);
983
984  TemplateParameterList *TempParams = D->getTemplateParameters();
985  TemplateParameterList *InstParams = SubstTemplateParams(TempParams);
986  if (!InstParams)
987    return NULL;
988
989  FunctionDecl *Instantiated = 0;
990  if (CXXMethodDecl *DMethod = dyn_cast<CXXMethodDecl>(D->getTemplatedDecl()))
991    Instantiated = cast_or_null<FunctionDecl>(VisitCXXMethodDecl(DMethod,
992                                                                 InstParams));
993  else
994    Instantiated = cast_or_null<FunctionDecl>(VisitFunctionDecl(
995                                                          D->getTemplatedDecl(),
996                                                                InstParams));
997
998  if (!Instantiated)
999    return 0;
1000
1001  // Link the instantiated function template declaration to the function
1002  // template from which it was instantiated.
1003  FunctionTemplateDecl *InstTemplate
1004    = Instantiated->getDescribedFunctionTemplate();
1005  InstTemplate->setAccess(D->getAccess());
1006  assert(InstTemplate &&
1007         "VisitFunctionDecl/CXXMethodDecl didn't create a template!");
1008
1009  bool isFriend = (InstTemplate->getFriendObjectKind() != Decl::FOK_None);
1010
1011  // Link the instantiation back to the pattern *unless* this is a
1012  // non-definition friend declaration.
1013  if (!InstTemplate->getInstantiatedFromMemberTemplate() &&
1014      !(isFriend && !D->getTemplatedDecl()->isThisDeclarationADefinition()))
1015    InstTemplate->setInstantiatedFromMemberTemplate(D);
1016
1017  // Make declarations visible in the appropriate context.
1018  if (!isFriend) {
1019    Owner->addDecl(InstTemplate);
1020  } else if (InstTemplate->getDeclContext()->isRecord() &&
1021             !D->getPreviousDecl()) {
1022    SemaRef.CheckFriendAccess(InstTemplate);
1023  }
1024
1025  return InstTemplate;
1026}
1027
1028Decl *TemplateDeclInstantiator::VisitCXXRecordDecl(CXXRecordDecl *D) {
1029  CXXRecordDecl *PrevDecl = 0;
1030  if (D->isInjectedClassName())
1031    PrevDecl = cast<CXXRecordDecl>(Owner);
1032  else if (D->getPreviousDecl()) {
1033    NamedDecl *Prev = SemaRef.FindInstantiatedDecl(D->getLocation(),
1034                                                   D->getPreviousDecl(),
1035                                                   TemplateArgs);
1036    if (!Prev) return 0;
1037    PrevDecl = cast<CXXRecordDecl>(Prev);
1038  }
1039
1040  CXXRecordDecl *Record
1041    = CXXRecordDecl::Create(SemaRef.Context, D->getTagKind(), Owner,
1042                            D->getLocStart(), D->getLocation(),
1043                            D->getIdentifier(), PrevDecl);
1044
1045  // Substitute the nested name specifier, if any.
1046  if (SubstQualifier(D, Record))
1047    return 0;
1048
1049  Record->setImplicit(D->isImplicit());
1050  // FIXME: Check against AS_none is an ugly hack to work around the issue that
1051  // the tag decls introduced by friend class declarations don't have an access
1052  // specifier. Remove once this area of the code gets sorted out.
1053  if (D->getAccess() != AS_none)
1054    Record->setAccess(D->getAccess());
1055  if (!D->isInjectedClassName())
1056    Record->setInstantiationOfMemberClass(D, TSK_ImplicitInstantiation);
1057
1058  // If the original function was part of a friend declaration,
1059  // inherit its namespace state.
1060  if (Decl::FriendObjectKind FOK = D->getFriendObjectKind())
1061    Record->setObjectOfFriendDecl(FOK == Decl::FOK_Declared);
1062
1063  // Make sure that anonymous structs and unions are recorded.
1064  if (D->isAnonymousStructOrUnion()) {
1065    Record->setAnonymousStructOrUnion(true);
1066    if (Record->getDeclContext()->getRedeclContext()->isFunctionOrMethod())
1067      SemaRef.CurrentInstantiationScope->InstantiatedLocal(D, Record);
1068  }
1069
1070  Owner->addDecl(Record);
1071  return Record;
1072}
1073
1074/// \brief Adjust the given function type for an instantiation of the
1075/// given declaration, to cope with modifications to the function's type that
1076/// aren't reflected in the type-source information.
1077///
1078/// \param D The declaration we're instantiating.
1079/// \param TInfo The already-instantiated type.
1080static QualType adjustFunctionTypeForInstantiation(ASTContext &Context,
1081                                                   FunctionDecl *D,
1082                                                   TypeSourceInfo *TInfo) {
1083  const FunctionProtoType *OrigFunc
1084    = D->getType()->castAs<FunctionProtoType>();
1085  const FunctionProtoType *NewFunc
1086    = TInfo->getType()->castAs<FunctionProtoType>();
1087  if (OrigFunc->getExtInfo() == NewFunc->getExtInfo())
1088    return TInfo->getType();
1089
1090  FunctionProtoType::ExtProtoInfo NewEPI = NewFunc->getExtProtoInfo();
1091  NewEPI.ExtInfo = OrigFunc->getExtInfo();
1092  return Context.getFunctionType(NewFunc->getResultType(),
1093                                 ArrayRef<QualType>(NewFunc->arg_type_begin(),
1094                                                    NewFunc->getNumArgs()),
1095                                 NewEPI);
1096}
1097
1098/// Normal class members are of more specific types and therefore
1099/// don't make it here.  This function serves two purposes:
1100///   1) instantiating function templates
1101///   2) substituting friend declarations
1102/// FIXME: preserve function definitions in case #2
1103Decl *TemplateDeclInstantiator::VisitFunctionDecl(FunctionDecl *D,
1104                                       TemplateParameterList *TemplateParams) {
1105  // Check whether there is already a function template specialization for
1106  // this declaration.
1107  FunctionTemplateDecl *FunctionTemplate = D->getDescribedFunctionTemplate();
1108  if (FunctionTemplate && !TemplateParams) {
1109    std::pair<const TemplateArgument *, unsigned> Innermost
1110      = TemplateArgs.getInnermost();
1111
1112    void *InsertPos = 0;
1113    FunctionDecl *SpecFunc
1114      = FunctionTemplate->findSpecialization(Innermost.first, Innermost.second,
1115                                             InsertPos);
1116
1117    // If we already have a function template specialization, return it.
1118    if (SpecFunc)
1119      return SpecFunc;
1120  }
1121
1122  bool isFriend;
1123  if (FunctionTemplate)
1124    isFriend = (FunctionTemplate->getFriendObjectKind() != Decl::FOK_None);
1125  else
1126    isFriend = (D->getFriendObjectKind() != Decl::FOK_None);
1127
1128  bool MergeWithParentScope = (TemplateParams != 0) ||
1129    Owner->isFunctionOrMethod() ||
1130    !(isa<Decl>(Owner) &&
1131      cast<Decl>(Owner)->isDefinedOutsideFunctionOrMethod());
1132  LocalInstantiationScope Scope(SemaRef, MergeWithParentScope);
1133
1134  SmallVector<ParmVarDecl *, 4> Params;
1135  TypeSourceInfo *TInfo = SubstFunctionType(D, Params);
1136  if (!TInfo)
1137    return 0;
1138  QualType T = adjustFunctionTypeForInstantiation(SemaRef.Context, D, TInfo);
1139
1140  NestedNameSpecifierLoc QualifierLoc = D->getQualifierLoc();
1141  if (QualifierLoc) {
1142    QualifierLoc = SemaRef.SubstNestedNameSpecifierLoc(QualifierLoc,
1143                                                       TemplateArgs);
1144    if (!QualifierLoc)
1145      return 0;
1146  }
1147
1148  // If we're instantiating a local function declaration, put the result
1149  // in the owner;  otherwise we need to find the instantiated context.
1150  DeclContext *DC;
1151  if (D->getDeclContext()->isFunctionOrMethod())
1152    DC = Owner;
1153  else if (isFriend && QualifierLoc) {
1154    CXXScopeSpec SS;
1155    SS.Adopt(QualifierLoc);
1156    DC = SemaRef.computeDeclContext(SS);
1157    if (!DC) return 0;
1158  } else {
1159    DC = SemaRef.FindInstantiatedContext(D->getLocation(), D->getDeclContext(),
1160                                         TemplateArgs);
1161  }
1162
1163  FunctionDecl *Function =
1164      FunctionDecl::Create(SemaRef.Context, DC, D->getInnerLocStart(),
1165                           D->getNameInfo(), T, TInfo,
1166                           D->getStorageClass(), D->getStorageClassAsWritten(),
1167                           D->isInlineSpecified(), D->hasWrittenPrototype(),
1168                           D->isConstexpr());
1169
1170  if (D->isInlined())
1171    Function->setImplicitlyInline();
1172
1173  if (QualifierLoc)
1174    Function->setQualifierInfo(QualifierLoc);
1175
1176  DeclContext *LexicalDC = Owner;
1177  if (!isFriend && D->isOutOfLine()) {
1178    assert(D->getDeclContext()->isFileContext());
1179    LexicalDC = D->getDeclContext();
1180  }
1181
1182  Function->setLexicalDeclContext(LexicalDC);
1183
1184  // Attach the parameters
1185  if (isa<FunctionProtoType>(Function->getType().IgnoreParens())) {
1186    // Adopt the already-instantiated parameters into our own context.
1187    for (unsigned P = 0; P < Params.size(); ++P)
1188      if (Params[P])
1189        Params[P]->setOwningFunction(Function);
1190  } else {
1191    // Since we were instantiated via a typedef of a function type, create
1192    // new parameters.
1193    const FunctionProtoType *Proto
1194      = Function->getType()->getAs<FunctionProtoType>();
1195    assert(Proto && "No function prototype in template instantiation?");
1196    for (FunctionProtoType::arg_type_iterator AI = Proto->arg_type_begin(),
1197         AE = Proto->arg_type_end(); AI != AE; ++AI) {
1198      ParmVarDecl *Param
1199        = SemaRef.BuildParmVarDeclForTypedef(Function, Function->getLocation(),
1200                                             *AI);
1201      Param->setScopeInfo(0, Params.size());
1202      Params.push_back(Param);
1203    }
1204  }
1205  Function->setParams(Params);
1206
1207  SourceLocation InstantiateAtPOI;
1208  if (TemplateParams) {
1209    // Our resulting instantiation is actually a function template, since we
1210    // are substituting only the outer template parameters. For example, given
1211    //
1212    //   template<typename T>
1213    //   struct X {
1214    //     template<typename U> friend void f(T, U);
1215    //   };
1216    //
1217    //   X<int> x;
1218    //
1219    // We are instantiating the friend function template "f" within X<int>,
1220    // which means substituting int for T, but leaving "f" as a friend function
1221    // template.
1222    // Build the function template itself.
1223    FunctionTemplate = FunctionTemplateDecl::Create(SemaRef.Context, DC,
1224                                                    Function->getLocation(),
1225                                                    Function->getDeclName(),
1226                                                    TemplateParams, Function);
1227    Function->setDescribedFunctionTemplate(FunctionTemplate);
1228
1229    FunctionTemplate->setLexicalDeclContext(LexicalDC);
1230
1231    if (isFriend && D->isThisDeclarationADefinition()) {
1232      // TODO: should we remember this connection regardless of whether
1233      // the friend declaration provided a body?
1234      FunctionTemplate->setInstantiatedFromMemberTemplate(
1235                                           D->getDescribedFunctionTemplate());
1236    }
1237  } else if (FunctionTemplate) {
1238    // Record this function template specialization.
1239    std::pair<const TemplateArgument *, unsigned> Innermost
1240      = TemplateArgs.getInnermost();
1241    Function->setFunctionTemplateSpecialization(FunctionTemplate,
1242                            TemplateArgumentList::CreateCopy(SemaRef.Context,
1243                                                             Innermost.first,
1244                                                             Innermost.second),
1245                                                /*InsertPos=*/0);
1246  } else if (isFriend) {
1247    // Note, we need this connection even if the friend doesn't have a body.
1248    // Its body may exist but not have been attached yet due to deferred
1249    // parsing.
1250    // FIXME: It might be cleaner to set this when attaching the body to the
1251    // friend function declaration, however that would require finding all the
1252    // instantiations and modifying them.
1253    Function->setInstantiationOfMemberFunction(D, TSK_ImplicitInstantiation);
1254  }
1255
1256  if (InitFunctionInstantiation(Function, D))
1257    Function->setInvalidDecl();
1258
1259  bool isExplicitSpecialization = false;
1260
1261  LookupResult Previous(SemaRef, Function->getDeclName(), SourceLocation(),
1262                        Sema::LookupOrdinaryName, Sema::ForRedeclaration);
1263
1264  if (DependentFunctionTemplateSpecializationInfo *Info
1265        = D->getDependentSpecializationInfo()) {
1266    assert(isFriend && "non-friend has dependent specialization info?");
1267
1268    // This needs to be set now for future sanity.
1269    Function->setObjectOfFriendDecl(/*HasPrevious*/ true);
1270
1271    // Instantiate the explicit template arguments.
1272    TemplateArgumentListInfo ExplicitArgs(Info->getLAngleLoc(),
1273                                          Info->getRAngleLoc());
1274    if (SemaRef.Subst(Info->getTemplateArgs(), Info->getNumTemplateArgs(),
1275                      ExplicitArgs, TemplateArgs))
1276      return 0;
1277
1278    // Map the candidate templates to their instantiations.
1279    for (unsigned I = 0, E = Info->getNumTemplates(); I != E; ++I) {
1280      Decl *Temp = SemaRef.FindInstantiatedDecl(D->getLocation(),
1281                                                Info->getTemplate(I),
1282                                                TemplateArgs);
1283      if (!Temp) return 0;
1284
1285      Previous.addDecl(cast<FunctionTemplateDecl>(Temp));
1286    }
1287
1288    if (SemaRef.CheckFunctionTemplateSpecialization(Function,
1289                                                    &ExplicitArgs,
1290                                                    Previous))
1291      Function->setInvalidDecl();
1292
1293    isExplicitSpecialization = true;
1294
1295  } else if (TemplateParams || !FunctionTemplate) {
1296    // Look only into the namespace where the friend would be declared to
1297    // find a previous declaration. This is the innermost enclosing namespace,
1298    // as described in ActOnFriendFunctionDecl.
1299    SemaRef.LookupQualifiedName(Previous, DC);
1300
1301    // In C++, the previous declaration we find might be a tag type
1302    // (class or enum). In this case, the new declaration will hide the
1303    // tag type. Note that this does does not apply if we're declaring a
1304    // typedef (C++ [dcl.typedef]p4).
1305    if (Previous.isSingleTagDecl())
1306      Previous.clear();
1307  }
1308
1309  SemaRef.CheckFunctionDeclaration(/*Scope*/ 0, Function, Previous,
1310                                   isExplicitSpecialization);
1311
1312  NamedDecl *PrincipalDecl = (TemplateParams
1313                              ? cast<NamedDecl>(FunctionTemplate)
1314                              : Function);
1315
1316  // If the original function was part of a friend declaration,
1317  // inherit its namespace state and add it to the owner.
1318  if (isFriend) {
1319    NamedDecl *PrevDecl;
1320    if (TemplateParams)
1321      PrevDecl = FunctionTemplate->getPreviousDecl();
1322    else
1323      PrevDecl = Function->getPreviousDecl();
1324
1325    PrincipalDecl->setObjectOfFriendDecl(PrevDecl != 0);
1326    DC->makeDeclVisibleInContext(PrincipalDecl);
1327
1328    bool queuedInstantiation = false;
1329
1330    // C++98 [temp.friend]p5: When a function is defined in a friend function
1331    //   declaration in a class template, the function is defined at each
1332    //   instantiation of the class template. The function is defined even if it
1333    //   is never used.
1334    // C++11 [temp.friend]p4: When a function is defined in a friend function
1335    //   declaration in a class template, the function is instantiated when the
1336    //   function is odr-used.
1337    //
1338    // If -Wc++98-compat is enabled, we go through the motions of checking for a
1339    // redefinition, but don't instantiate the function.
1340    if ((!SemaRef.getLangOpts().CPlusPlus11 ||
1341         SemaRef.Diags.getDiagnosticLevel(
1342             diag::warn_cxx98_compat_friend_redefinition,
1343             Function->getLocation())
1344           != DiagnosticsEngine::Ignored) &&
1345        D->isThisDeclarationADefinition()) {
1346      // Check for a function body.
1347      const FunctionDecl *Definition = 0;
1348      if (Function->isDefined(Definition) &&
1349          Definition->getTemplateSpecializationKind() == TSK_Undeclared) {
1350        SemaRef.Diag(Function->getLocation(),
1351                     SemaRef.getLangOpts().CPlusPlus11 ?
1352                       diag::warn_cxx98_compat_friend_redefinition :
1353                       diag::err_redefinition) << Function->getDeclName();
1354        SemaRef.Diag(Definition->getLocation(), diag::note_previous_definition);
1355        if (!SemaRef.getLangOpts().CPlusPlus11)
1356          Function->setInvalidDecl();
1357      }
1358      // Check for redefinitions due to other instantiations of this or
1359      // a similar friend function.
1360      else for (FunctionDecl::redecl_iterator R = Function->redecls_begin(),
1361                                           REnd = Function->redecls_end();
1362                R != REnd; ++R) {
1363        if (*R == Function)
1364          continue;
1365        switch (R->getFriendObjectKind()) {
1366        case Decl::FOK_None:
1367          if (!SemaRef.getLangOpts().CPlusPlus11 &&
1368              !queuedInstantiation && R->isUsed(false)) {
1369            if (MemberSpecializationInfo *MSInfo
1370                = Function->getMemberSpecializationInfo()) {
1371              if (MSInfo->getPointOfInstantiation().isInvalid()) {
1372                SourceLocation Loc = R->getLocation(); // FIXME
1373                MSInfo->setPointOfInstantiation(Loc);
1374                SemaRef.PendingLocalImplicitInstantiations.push_back(
1375                                                 std::make_pair(Function, Loc));
1376                queuedInstantiation = true;
1377              }
1378            }
1379          }
1380          break;
1381        default:
1382          if (const FunctionDecl *RPattern
1383              = R->getTemplateInstantiationPattern())
1384            if (RPattern->isDefined(RPattern)) {
1385              SemaRef.Diag(Function->getLocation(),
1386                           SemaRef.getLangOpts().CPlusPlus11 ?
1387                             diag::warn_cxx98_compat_friend_redefinition :
1388                             diag::err_redefinition)
1389                << Function->getDeclName();
1390              SemaRef.Diag(R->getLocation(), diag::note_previous_definition);
1391              if (!SemaRef.getLangOpts().CPlusPlus11)
1392                Function->setInvalidDecl();
1393              break;
1394            }
1395        }
1396      }
1397    }
1398  }
1399
1400  if (Function->isOverloadedOperator() && !DC->isRecord() &&
1401      PrincipalDecl->isInIdentifierNamespace(Decl::IDNS_Ordinary))
1402    PrincipalDecl->setNonMemberOperator();
1403
1404  assert(!D->isDefaulted() && "only methods should be defaulted");
1405  return Function;
1406}
1407
1408Decl *
1409TemplateDeclInstantiator::VisitCXXMethodDecl(CXXMethodDecl *D,
1410                                      TemplateParameterList *TemplateParams,
1411                                      bool IsClassScopeSpecialization) {
1412  FunctionTemplateDecl *FunctionTemplate = D->getDescribedFunctionTemplate();
1413  if (FunctionTemplate && !TemplateParams) {
1414    // We are creating a function template specialization from a function
1415    // template. Check whether there is already a function template
1416    // specialization for this particular set of template arguments.
1417    std::pair<const TemplateArgument *, unsigned> Innermost
1418      = TemplateArgs.getInnermost();
1419
1420    void *InsertPos = 0;
1421    FunctionDecl *SpecFunc
1422      = FunctionTemplate->findSpecialization(Innermost.first, Innermost.second,
1423                                             InsertPos);
1424
1425    // If we already have a function template specialization, return it.
1426    if (SpecFunc)
1427      return SpecFunc;
1428  }
1429
1430  bool isFriend;
1431  if (FunctionTemplate)
1432    isFriend = (FunctionTemplate->getFriendObjectKind() != Decl::FOK_None);
1433  else
1434    isFriend = (D->getFriendObjectKind() != Decl::FOK_None);
1435
1436  bool MergeWithParentScope = (TemplateParams != 0) ||
1437    !(isa<Decl>(Owner) &&
1438      cast<Decl>(Owner)->isDefinedOutsideFunctionOrMethod());
1439  LocalInstantiationScope Scope(SemaRef, MergeWithParentScope);
1440
1441  // Instantiate enclosing template arguments for friends.
1442  SmallVector<TemplateParameterList *, 4> TempParamLists;
1443  unsigned NumTempParamLists = 0;
1444  if (isFriend && (NumTempParamLists = D->getNumTemplateParameterLists())) {
1445    TempParamLists.set_size(NumTempParamLists);
1446    for (unsigned I = 0; I != NumTempParamLists; ++I) {
1447      TemplateParameterList *TempParams = D->getTemplateParameterList(I);
1448      TemplateParameterList *InstParams = SubstTemplateParams(TempParams);
1449      if (!InstParams)
1450        return NULL;
1451      TempParamLists[I] = InstParams;
1452    }
1453  }
1454
1455  SmallVector<ParmVarDecl *, 4> Params;
1456  TypeSourceInfo *TInfo = SubstFunctionType(D, Params);
1457  if (!TInfo)
1458    return 0;
1459  QualType T = adjustFunctionTypeForInstantiation(SemaRef.Context, D, TInfo);
1460
1461  // \brief If the type of this function, after ignoring parentheses,
1462  // is not *directly* a function type, then we're instantiating a function
1463  // that was declared via a typedef, e.g.,
1464  //
1465  //   typedef int functype(int, int);
1466  //   functype func;
1467  //
1468  // In this case, we'll just go instantiate the ParmVarDecls that we
1469  // synthesized in the method declaration.
1470  if (!isa<FunctionProtoType>(T.IgnoreParens())) {
1471    assert(!Params.size() && "Instantiating type could not yield parameters");
1472    SmallVector<QualType, 4> ParamTypes;
1473    if (SemaRef.SubstParmTypes(D->getLocation(), D->param_begin(),
1474                               D->getNumParams(), TemplateArgs, ParamTypes,
1475                               &Params))
1476      return 0;
1477  }
1478
1479  NestedNameSpecifierLoc QualifierLoc = D->getQualifierLoc();
1480  if (QualifierLoc) {
1481    QualifierLoc = SemaRef.SubstNestedNameSpecifierLoc(QualifierLoc,
1482                                                 TemplateArgs);
1483    if (!QualifierLoc)
1484      return 0;
1485  }
1486
1487  DeclContext *DC = Owner;
1488  if (isFriend) {
1489    if (QualifierLoc) {
1490      CXXScopeSpec SS;
1491      SS.Adopt(QualifierLoc);
1492      DC = SemaRef.computeDeclContext(SS);
1493
1494      if (DC && SemaRef.RequireCompleteDeclContext(SS, DC))
1495        return 0;
1496    } else {
1497      DC = SemaRef.FindInstantiatedContext(D->getLocation(),
1498                                           D->getDeclContext(),
1499                                           TemplateArgs);
1500    }
1501    if (!DC) return 0;
1502  }
1503
1504  // Build the instantiated method declaration.
1505  CXXRecordDecl *Record = cast<CXXRecordDecl>(DC);
1506  CXXMethodDecl *Method = 0;
1507
1508  SourceLocation StartLoc = D->getInnerLocStart();
1509  DeclarationNameInfo NameInfo
1510    = SemaRef.SubstDeclarationNameInfo(D->getNameInfo(), TemplateArgs);
1511  if (CXXConstructorDecl *Constructor = dyn_cast<CXXConstructorDecl>(D)) {
1512    Method = CXXConstructorDecl::Create(SemaRef.Context, Record,
1513                                        StartLoc, NameInfo, T, TInfo,
1514                                        Constructor->isExplicit(),
1515                                        Constructor->isInlineSpecified(),
1516                                        false, Constructor->isConstexpr());
1517  } else if (CXXDestructorDecl *Destructor = dyn_cast<CXXDestructorDecl>(D)) {
1518    Method = CXXDestructorDecl::Create(SemaRef.Context, Record,
1519                                       StartLoc, NameInfo, T, TInfo,
1520                                       Destructor->isInlineSpecified(),
1521                                       false);
1522  } else if (CXXConversionDecl *Conversion = dyn_cast<CXXConversionDecl>(D)) {
1523    Method = CXXConversionDecl::Create(SemaRef.Context, Record,
1524                                       StartLoc, NameInfo, T, TInfo,
1525                                       Conversion->isInlineSpecified(),
1526                                       Conversion->isExplicit(),
1527                                       Conversion->isConstexpr(),
1528                                       Conversion->getLocEnd());
1529  } else {
1530    Method = CXXMethodDecl::Create(SemaRef.Context, Record,
1531                                   StartLoc, NameInfo, T, TInfo,
1532                                   D->isStatic(),
1533                                   D->getStorageClassAsWritten(),
1534                                   D->isInlineSpecified(),
1535                                   D->isConstexpr(), D->getLocEnd());
1536  }
1537
1538  if (D->isInlined())
1539    Method->setImplicitlyInline();
1540
1541  if (QualifierLoc)
1542    Method->setQualifierInfo(QualifierLoc);
1543
1544  if (TemplateParams) {
1545    // Our resulting instantiation is actually a function template, since we
1546    // are substituting only the outer template parameters. For example, given
1547    //
1548    //   template<typename T>
1549    //   struct X {
1550    //     template<typename U> void f(T, U);
1551    //   };
1552    //
1553    //   X<int> x;
1554    //
1555    // We are instantiating the member template "f" within X<int>, which means
1556    // substituting int for T, but leaving "f" as a member function template.
1557    // Build the function template itself.
1558    FunctionTemplate = FunctionTemplateDecl::Create(SemaRef.Context, Record,
1559                                                    Method->getLocation(),
1560                                                    Method->getDeclName(),
1561                                                    TemplateParams, Method);
1562    if (isFriend) {
1563      FunctionTemplate->setLexicalDeclContext(Owner);
1564      FunctionTemplate->setObjectOfFriendDecl(true);
1565    } else if (D->isOutOfLine())
1566      FunctionTemplate->setLexicalDeclContext(D->getLexicalDeclContext());
1567    Method->setDescribedFunctionTemplate(FunctionTemplate);
1568  } else if (FunctionTemplate) {
1569    // Record this function template specialization.
1570    std::pair<const TemplateArgument *, unsigned> Innermost
1571      = TemplateArgs.getInnermost();
1572    Method->setFunctionTemplateSpecialization(FunctionTemplate,
1573                         TemplateArgumentList::CreateCopy(SemaRef.Context,
1574                                                          Innermost.first,
1575                                                          Innermost.second),
1576                                              /*InsertPos=*/0);
1577  } else if (!isFriend) {
1578    // Record that this is an instantiation of a member function.
1579    Method->setInstantiationOfMemberFunction(D, TSK_ImplicitInstantiation);
1580  }
1581
1582  // If we are instantiating a member function defined
1583  // out-of-line, the instantiation will have the same lexical
1584  // context (which will be a namespace scope) as the template.
1585  if (isFriend) {
1586    if (NumTempParamLists)
1587      Method->setTemplateParameterListsInfo(SemaRef.Context,
1588                                            NumTempParamLists,
1589                                            TempParamLists.data());
1590
1591    Method->setLexicalDeclContext(Owner);
1592    Method->setObjectOfFriendDecl(true);
1593  } else if (D->isOutOfLine())
1594    Method->setLexicalDeclContext(D->getLexicalDeclContext());
1595
1596  // Attach the parameters
1597  for (unsigned P = 0; P < Params.size(); ++P)
1598    Params[P]->setOwningFunction(Method);
1599  Method->setParams(Params);
1600
1601  if (InitMethodInstantiation(Method, D))
1602    Method->setInvalidDecl();
1603
1604  LookupResult Previous(SemaRef, NameInfo, Sema::LookupOrdinaryName,
1605                        Sema::ForRedeclaration);
1606
1607  if (!FunctionTemplate || TemplateParams || isFriend) {
1608    SemaRef.LookupQualifiedName(Previous, Record);
1609
1610    // In C++, the previous declaration we find might be a tag type
1611    // (class or enum). In this case, the new declaration will hide the
1612    // tag type. Note that this does does not apply if we're declaring a
1613    // typedef (C++ [dcl.typedef]p4).
1614    if (Previous.isSingleTagDecl())
1615      Previous.clear();
1616  }
1617
1618  if (!IsClassScopeSpecialization)
1619    SemaRef.CheckFunctionDeclaration(0, Method, Previous, false);
1620
1621  if (D->isPure())
1622    SemaRef.CheckPureMethod(Method, SourceRange());
1623
1624  // Propagate access.  For a non-friend declaration, the access is
1625  // whatever we're propagating from.  For a friend, it should be the
1626  // previous declaration we just found.
1627  if (isFriend && Method->getPreviousDecl())
1628    Method->setAccess(Method->getPreviousDecl()->getAccess());
1629  else
1630    Method->setAccess(D->getAccess());
1631  if (FunctionTemplate)
1632    FunctionTemplate->setAccess(Method->getAccess());
1633
1634  SemaRef.CheckOverrideControl(Method);
1635
1636  // If a function is defined as defaulted or deleted, mark it as such now.
1637  if (D->isExplicitlyDefaulted())
1638    SemaRef.SetDeclDefaulted(Method, Method->getLocation());
1639  if (D->isDeletedAsWritten())
1640    SemaRef.SetDeclDeleted(Method, Method->getLocation());
1641
1642  // If there's a function template, let our caller handle it.
1643  if (FunctionTemplate) {
1644    // do nothing
1645
1646  // Don't hide a (potentially) valid declaration with an invalid one.
1647  } else if (Method->isInvalidDecl() && !Previous.empty()) {
1648    // do nothing
1649
1650  // Otherwise, check access to friends and make them visible.
1651  } else if (isFriend) {
1652    // We only need to re-check access for methods which we didn't
1653    // manage to match during parsing.
1654    if (!D->getPreviousDecl())
1655      SemaRef.CheckFriendAccess(Method);
1656
1657    Record->makeDeclVisibleInContext(Method);
1658
1659  // Otherwise, add the declaration.  We don't need to do this for
1660  // class-scope specializations because we'll have matched them with
1661  // the appropriate template.
1662  } else if (!IsClassScopeSpecialization) {
1663    Owner->addDecl(Method);
1664  }
1665
1666  return Method;
1667}
1668
1669Decl *TemplateDeclInstantiator::VisitCXXConstructorDecl(CXXConstructorDecl *D) {
1670  return VisitCXXMethodDecl(D);
1671}
1672
1673Decl *TemplateDeclInstantiator::VisitCXXDestructorDecl(CXXDestructorDecl *D) {
1674  return VisitCXXMethodDecl(D);
1675}
1676
1677Decl *TemplateDeclInstantiator::VisitCXXConversionDecl(CXXConversionDecl *D) {
1678  return VisitCXXMethodDecl(D);
1679}
1680
1681ParmVarDecl *TemplateDeclInstantiator::VisitParmVarDecl(ParmVarDecl *D) {
1682  return SemaRef.SubstParmVarDecl(D, TemplateArgs, /*indexAdjustment*/ 0, None,
1683                                  /*ExpectParameterPack=*/ false);
1684}
1685
1686Decl *TemplateDeclInstantiator::VisitTemplateTypeParmDecl(
1687                                                    TemplateTypeParmDecl *D) {
1688  // TODO: don't always clone when decls are refcounted.
1689  assert(D->getTypeForDecl()->isTemplateTypeParmType());
1690
1691  TemplateTypeParmDecl *Inst =
1692    TemplateTypeParmDecl::Create(SemaRef.Context, Owner,
1693                                 D->getLocStart(), D->getLocation(),
1694                                 D->getDepth() - TemplateArgs.getNumLevels(),
1695                                 D->getIndex(), D->getIdentifier(),
1696                                 D->wasDeclaredWithTypename(),
1697                                 D->isParameterPack());
1698  Inst->setAccess(AS_public);
1699
1700  if (D->hasDefaultArgument())
1701    Inst->setDefaultArgument(D->getDefaultArgumentInfo(), false);
1702
1703  // Introduce this template parameter's instantiation into the instantiation
1704  // scope.
1705  SemaRef.CurrentInstantiationScope->InstantiatedLocal(D, Inst);
1706
1707  return Inst;
1708}
1709
1710Decl *TemplateDeclInstantiator::VisitNonTypeTemplateParmDecl(
1711                                                 NonTypeTemplateParmDecl *D) {
1712  // Substitute into the type of the non-type template parameter.
1713  TypeLoc TL = D->getTypeSourceInfo()->getTypeLoc();
1714  SmallVector<TypeSourceInfo *, 4> ExpandedParameterPackTypesAsWritten;
1715  SmallVector<QualType, 4> ExpandedParameterPackTypes;
1716  bool IsExpandedParameterPack = false;
1717  TypeSourceInfo *DI;
1718  QualType T;
1719  bool Invalid = false;
1720
1721  if (D->isExpandedParameterPack()) {
1722    // The non-type template parameter pack is an already-expanded pack
1723    // expansion of types. Substitute into each of the expanded types.
1724    ExpandedParameterPackTypes.reserve(D->getNumExpansionTypes());
1725    ExpandedParameterPackTypesAsWritten.reserve(D->getNumExpansionTypes());
1726    for (unsigned I = 0, N = D->getNumExpansionTypes(); I != N; ++I) {
1727      TypeSourceInfo *NewDI =SemaRef.SubstType(D->getExpansionTypeSourceInfo(I),
1728                                               TemplateArgs,
1729                                               D->getLocation(),
1730                                               D->getDeclName());
1731      if (!NewDI)
1732        return 0;
1733
1734      ExpandedParameterPackTypesAsWritten.push_back(NewDI);
1735      QualType NewT =SemaRef.CheckNonTypeTemplateParameterType(NewDI->getType(),
1736                                                              D->getLocation());
1737      if (NewT.isNull())
1738        return 0;
1739      ExpandedParameterPackTypes.push_back(NewT);
1740    }
1741
1742    IsExpandedParameterPack = true;
1743    DI = D->getTypeSourceInfo();
1744    T = DI->getType();
1745  } else if (D->isPackExpansion()) {
1746    // The non-type template parameter pack's type is a pack expansion of types.
1747    // Determine whether we need to expand this parameter pack into separate
1748    // types.
1749    PackExpansionTypeLoc Expansion = TL.castAs<PackExpansionTypeLoc>();
1750    TypeLoc Pattern = Expansion.getPatternLoc();
1751    SmallVector<UnexpandedParameterPack, 2> Unexpanded;
1752    SemaRef.collectUnexpandedParameterPacks(Pattern, Unexpanded);
1753
1754    // Determine whether the set of unexpanded parameter packs can and should
1755    // be expanded.
1756    bool Expand = true;
1757    bool RetainExpansion = false;
1758    Optional<unsigned> OrigNumExpansions
1759      = Expansion.getTypePtr()->getNumExpansions();
1760    Optional<unsigned> NumExpansions = OrigNumExpansions;
1761    if (SemaRef.CheckParameterPacksForExpansion(Expansion.getEllipsisLoc(),
1762                                                Pattern.getSourceRange(),
1763                                                Unexpanded,
1764                                                TemplateArgs,
1765                                                Expand, RetainExpansion,
1766                                                NumExpansions))
1767      return 0;
1768
1769    if (Expand) {
1770      for (unsigned I = 0; I != *NumExpansions; ++I) {
1771        Sema::ArgumentPackSubstitutionIndexRAII SubstIndex(SemaRef, I);
1772        TypeSourceInfo *NewDI = SemaRef.SubstType(Pattern, TemplateArgs,
1773                                                  D->getLocation(),
1774                                                  D->getDeclName());
1775        if (!NewDI)
1776          return 0;
1777
1778        ExpandedParameterPackTypesAsWritten.push_back(NewDI);
1779        QualType NewT = SemaRef.CheckNonTypeTemplateParameterType(
1780                                                              NewDI->getType(),
1781                                                              D->getLocation());
1782        if (NewT.isNull())
1783          return 0;
1784        ExpandedParameterPackTypes.push_back(NewT);
1785      }
1786
1787      // Note that we have an expanded parameter pack. The "type" of this
1788      // expanded parameter pack is the original expansion type, but callers
1789      // will end up using the expanded parameter pack types for type-checking.
1790      IsExpandedParameterPack = true;
1791      DI = D->getTypeSourceInfo();
1792      T = DI->getType();
1793    } else {
1794      // We cannot fully expand the pack expansion now, so substitute into the
1795      // pattern and create a new pack expansion type.
1796      Sema::ArgumentPackSubstitutionIndexRAII SubstIndex(SemaRef, -1);
1797      TypeSourceInfo *NewPattern = SemaRef.SubstType(Pattern, TemplateArgs,
1798                                                     D->getLocation(),
1799                                                     D->getDeclName());
1800      if (!NewPattern)
1801        return 0;
1802
1803      DI = SemaRef.CheckPackExpansion(NewPattern, Expansion.getEllipsisLoc(),
1804                                      NumExpansions);
1805      if (!DI)
1806        return 0;
1807
1808      T = DI->getType();
1809    }
1810  } else {
1811    // Simple case: substitution into a parameter that is not a parameter pack.
1812    DI = SemaRef.SubstType(D->getTypeSourceInfo(), TemplateArgs,
1813                           D->getLocation(), D->getDeclName());
1814    if (!DI)
1815      return 0;
1816
1817    // Check that this type is acceptable for a non-type template parameter.
1818    T = SemaRef.CheckNonTypeTemplateParameterType(DI->getType(),
1819                                                  D->getLocation());
1820    if (T.isNull()) {
1821      T = SemaRef.Context.IntTy;
1822      Invalid = true;
1823    }
1824  }
1825
1826  NonTypeTemplateParmDecl *Param;
1827  if (IsExpandedParameterPack)
1828    Param = NonTypeTemplateParmDecl::Create(SemaRef.Context, Owner,
1829                                            D->getInnerLocStart(),
1830                                            D->getLocation(),
1831                                    D->getDepth() - TemplateArgs.getNumLevels(),
1832                                            D->getPosition(),
1833                                            D->getIdentifier(), T,
1834                                            DI,
1835                                            ExpandedParameterPackTypes.data(),
1836                                            ExpandedParameterPackTypes.size(),
1837                                    ExpandedParameterPackTypesAsWritten.data());
1838  else
1839    Param = NonTypeTemplateParmDecl::Create(SemaRef.Context, Owner,
1840                                            D->getInnerLocStart(),
1841                                            D->getLocation(),
1842                                    D->getDepth() - TemplateArgs.getNumLevels(),
1843                                            D->getPosition(),
1844                                            D->getIdentifier(), T,
1845                                            D->isParameterPack(), DI);
1846
1847  Param->setAccess(AS_public);
1848  if (Invalid)
1849    Param->setInvalidDecl();
1850
1851  Param->setDefaultArgument(D->getDefaultArgument(), false);
1852
1853  // Introduce this template parameter's instantiation into the instantiation
1854  // scope.
1855  SemaRef.CurrentInstantiationScope->InstantiatedLocal(D, Param);
1856  return Param;
1857}
1858
1859static void collectUnexpandedParameterPacks(
1860    Sema &S,
1861    TemplateParameterList *Params,
1862    SmallVectorImpl<UnexpandedParameterPack> &Unexpanded) {
1863  for (TemplateParameterList::const_iterator I = Params->begin(),
1864                                             E = Params->end(); I != E; ++I) {
1865    if ((*I)->isTemplateParameterPack())
1866      continue;
1867    if (NonTypeTemplateParmDecl *NTTP = dyn_cast<NonTypeTemplateParmDecl>(*I))
1868      S.collectUnexpandedParameterPacks(NTTP->getTypeSourceInfo()->getTypeLoc(),
1869                                        Unexpanded);
1870    if (TemplateTemplateParmDecl *TTP = dyn_cast<TemplateTemplateParmDecl>(*I))
1871      collectUnexpandedParameterPacks(S, TTP->getTemplateParameters(),
1872                                      Unexpanded);
1873  }
1874}
1875
1876Decl *
1877TemplateDeclInstantiator::VisitTemplateTemplateParmDecl(
1878                                                  TemplateTemplateParmDecl *D) {
1879  // Instantiate the template parameter list of the template template parameter.
1880  TemplateParameterList *TempParams = D->getTemplateParameters();
1881  TemplateParameterList *InstParams;
1882  SmallVector<TemplateParameterList*, 8> ExpandedParams;
1883
1884  bool IsExpandedParameterPack = false;
1885
1886  if (D->isExpandedParameterPack()) {
1887    // The template template parameter pack is an already-expanded pack
1888    // expansion of template parameters. Substitute into each of the expanded
1889    // parameters.
1890    ExpandedParams.reserve(D->getNumExpansionTemplateParameters());
1891    for (unsigned I = 0, N = D->getNumExpansionTemplateParameters();
1892         I != N; ++I) {
1893      LocalInstantiationScope Scope(SemaRef);
1894      TemplateParameterList *Expansion =
1895        SubstTemplateParams(D->getExpansionTemplateParameters(I));
1896      if (!Expansion)
1897        return 0;
1898      ExpandedParams.push_back(Expansion);
1899    }
1900
1901    IsExpandedParameterPack = true;
1902    InstParams = TempParams;
1903  } else if (D->isPackExpansion()) {
1904    // The template template parameter pack expands to a pack of template
1905    // template parameters. Determine whether we need to expand this parameter
1906    // pack into separate parameters.
1907    SmallVector<UnexpandedParameterPack, 2> Unexpanded;
1908    collectUnexpandedParameterPacks(SemaRef, D->getTemplateParameters(),
1909                                    Unexpanded);
1910
1911    // Determine whether the set of unexpanded parameter packs can and should
1912    // be expanded.
1913    bool Expand = true;
1914    bool RetainExpansion = false;
1915    Optional<unsigned> NumExpansions;
1916    if (SemaRef.CheckParameterPacksForExpansion(D->getLocation(),
1917                                                TempParams->getSourceRange(),
1918                                                Unexpanded,
1919                                                TemplateArgs,
1920                                                Expand, RetainExpansion,
1921                                                NumExpansions))
1922      return 0;
1923
1924    if (Expand) {
1925      for (unsigned I = 0; I != *NumExpansions; ++I) {
1926        Sema::ArgumentPackSubstitutionIndexRAII SubstIndex(SemaRef, I);
1927        LocalInstantiationScope Scope(SemaRef);
1928        TemplateParameterList *Expansion = SubstTemplateParams(TempParams);
1929        if (!Expansion)
1930          return 0;
1931        ExpandedParams.push_back(Expansion);
1932      }
1933
1934      // Note that we have an expanded parameter pack. The "type" of this
1935      // expanded parameter pack is the original expansion type, but callers
1936      // will end up using the expanded parameter pack types for type-checking.
1937      IsExpandedParameterPack = true;
1938      InstParams = TempParams;
1939    } else {
1940      // We cannot fully expand the pack expansion now, so just substitute
1941      // into the pattern.
1942      Sema::ArgumentPackSubstitutionIndexRAII SubstIndex(SemaRef, -1);
1943
1944      LocalInstantiationScope Scope(SemaRef);
1945      InstParams = SubstTemplateParams(TempParams);
1946      if (!InstParams)
1947        return 0;
1948    }
1949  } else {
1950    // Perform the actual substitution of template parameters within a new,
1951    // local instantiation scope.
1952    LocalInstantiationScope Scope(SemaRef);
1953    InstParams = SubstTemplateParams(TempParams);
1954    if (!InstParams)
1955      return 0;
1956  }
1957
1958  // Build the template template parameter.
1959  TemplateTemplateParmDecl *Param;
1960  if (IsExpandedParameterPack)
1961    Param = TemplateTemplateParmDecl::Create(SemaRef.Context, Owner,
1962                                             D->getLocation(),
1963                                   D->getDepth() - TemplateArgs.getNumLevels(),
1964                                             D->getPosition(),
1965                                             D->getIdentifier(), InstParams,
1966                                             ExpandedParams);
1967  else
1968    Param = TemplateTemplateParmDecl::Create(SemaRef.Context, Owner,
1969                                             D->getLocation(),
1970                                   D->getDepth() - TemplateArgs.getNumLevels(),
1971                                             D->getPosition(),
1972                                             D->isParameterPack(),
1973                                             D->getIdentifier(), InstParams);
1974  Param->setDefaultArgument(D->getDefaultArgument(), false);
1975  Param->setAccess(AS_public);
1976
1977  // Introduce this template parameter's instantiation into the instantiation
1978  // scope.
1979  SemaRef.CurrentInstantiationScope->InstantiatedLocal(D, Param);
1980
1981  return Param;
1982}
1983
1984Decl *TemplateDeclInstantiator::VisitUsingDirectiveDecl(UsingDirectiveDecl *D) {
1985  // Using directives are never dependent (and never contain any types or
1986  // expressions), so they require no explicit instantiation work.
1987
1988  UsingDirectiveDecl *Inst
1989    = UsingDirectiveDecl::Create(SemaRef.Context, Owner, D->getLocation(),
1990                                 D->getNamespaceKeyLocation(),
1991                                 D->getQualifierLoc(),
1992                                 D->getIdentLocation(),
1993                                 D->getNominatedNamespace(),
1994                                 D->getCommonAncestor());
1995
1996  // Add the using directive to its declaration context
1997  // only if this is not a function or method.
1998  if (!Owner->isFunctionOrMethod())
1999    Owner->addDecl(Inst);
2000
2001  return Inst;
2002}
2003
2004Decl *TemplateDeclInstantiator::VisitUsingDecl(UsingDecl *D) {
2005
2006  // The nested name specifier may be dependent, for example
2007  //     template <typename T> struct t {
2008  //       struct s1 { T f1(); };
2009  //       struct s2 : s1 { using s1::f1; };
2010  //     };
2011  //     template struct t<int>;
2012  // Here, in using s1::f1, s1 refers to t<T>::s1;
2013  // we need to substitute for t<int>::s1.
2014  NestedNameSpecifierLoc QualifierLoc
2015    = SemaRef.SubstNestedNameSpecifierLoc(D->getQualifierLoc(),
2016                                          TemplateArgs);
2017  if (!QualifierLoc)
2018    return 0;
2019
2020  // The name info is non-dependent, so no transformation
2021  // is required.
2022  DeclarationNameInfo NameInfo = D->getNameInfo();
2023
2024  // We only need to do redeclaration lookups if we're in a class
2025  // scope (in fact, it's not really even possible in non-class
2026  // scopes).
2027  bool CheckRedeclaration = Owner->isRecord();
2028
2029  LookupResult Prev(SemaRef, NameInfo, Sema::LookupUsingDeclName,
2030                    Sema::ForRedeclaration);
2031
2032  UsingDecl *NewUD = UsingDecl::Create(SemaRef.Context, Owner,
2033                                       D->getUsingLocation(),
2034                                       QualifierLoc,
2035                                       NameInfo,
2036                                       D->isTypeName());
2037
2038  CXXScopeSpec SS;
2039  SS.Adopt(QualifierLoc);
2040  if (CheckRedeclaration) {
2041    Prev.setHideTags(false);
2042    SemaRef.LookupQualifiedName(Prev, Owner);
2043
2044    // Check for invalid redeclarations.
2045    if (SemaRef.CheckUsingDeclRedeclaration(D->getUsingLocation(),
2046                                            D->isTypeName(), SS,
2047                                            D->getLocation(), Prev))
2048      NewUD->setInvalidDecl();
2049
2050  }
2051
2052  if (!NewUD->isInvalidDecl() &&
2053      SemaRef.CheckUsingDeclQualifier(D->getUsingLocation(), SS,
2054                                      D->getLocation()))
2055    NewUD->setInvalidDecl();
2056
2057  SemaRef.Context.setInstantiatedFromUsingDecl(NewUD, D);
2058  NewUD->setAccess(D->getAccess());
2059  Owner->addDecl(NewUD);
2060
2061  // Don't process the shadow decls for an invalid decl.
2062  if (NewUD->isInvalidDecl())
2063    return NewUD;
2064
2065  if (NameInfo.getName().getNameKind() == DeclarationName::CXXConstructorName) {
2066    if (SemaRef.CheckInheritingConstructorUsingDecl(NewUD))
2067      NewUD->setInvalidDecl();
2068    return NewUD;
2069  }
2070
2071  bool isFunctionScope = Owner->isFunctionOrMethod();
2072
2073  // Process the shadow decls.
2074  for (UsingDecl::shadow_iterator I = D->shadow_begin(), E = D->shadow_end();
2075         I != E; ++I) {
2076    UsingShadowDecl *Shadow = *I;
2077    NamedDecl *InstTarget =
2078      cast_or_null<NamedDecl>(SemaRef.FindInstantiatedDecl(
2079                                                          Shadow->getLocation(),
2080                                                        Shadow->getTargetDecl(),
2081                                                           TemplateArgs));
2082    if (!InstTarget)
2083      return 0;
2084
2085    if (CheckRedeclaration &&
2086        SemaRef.CheckUsingShadowDecl(NewUD, InstTarget, Prev))
2087      continue;
2088
2089    UsingShadowDecl *InstShadow
2090      = SemaRef.BuildUsingShadowDecl(/*Scope*/ 0, NewUD, InstTarget);
2091    SemaRef.Context.setInstantiatedFromUsingShadowDecl(InstShadow, Shadow);
2092
2093    if (isFunctionScope)
2094      SemaRef.CurrentInstantiationScope->InstantiatedLocal(Shadow, InstShadow);
2095  }
2096
2097  return NewUD;
2098}
2099
2100Decl *TemplateDeclInstantiator::VisitUsingShadowDecl(UsingShadowDecl *D) {
2101  // Ignore these;  we handle them in bulk when processing the UsingDecl.
2102  return 0;
2103}
2104
2105Decl * TemplateDeclInstantiator
2106    ::VisitUnresolvedUsingTypenameDecl(UnresolvedUsingTypenameDecl *D) {
2107  NestedNameSpecifierLoc QualifierLoc
2108    = SemaRef.SubstNestedNameSpecifierLoc(D->getQualifierLoc(),
2109                                          TemplateArgs);
2110  if (!QualifierLoc)
2111    return 0;
2112
2113  CXXScopeSpec SS;
2114  SS.Adopt(QualifierLoc);
2115
2116  // Since NameInfo refers to a typename, it cannot be a C++ special name.
2117  // Hence, no transformation is required for it.
2118  DeclarationNameInfo NameInfo(D->getDeclName(), D->getLocation());
2119  NamedDecl *UD =
2120    SemaRef.BuildUsingDeclaration(/*Scope*/ 0, D->getAccess(),
2121                                  D->getUsingLoc(), SS, NameInfo, 0,
2122                                  /*instantiation*/ true,
2123                                  /*typename*/ true, D->getTypenameLoc());
2124  if (UD)
2125    SemaRef.Context.setInstantiatedFromUsingDecl(cast<UsingDecl>(UD), D);
2126
2127  return UD;
2128}
2129
2130Decl * TemplateDeclInstantiator
2131    ::VisitUnresolvedUsingValueDecl(UnresolvedUsingValueDecl *D) {
2132  NestedNameSpecifierLoc QualifierLoc
2133      = SemaRef.SubstNestedNameSpecifierLoc(D->getQualifierLoc(), TemplateArgs);
2134  if (!QualifierLoc)
2135    return 0;
2136
2137  CXXScopeSpec SS;
2138  SS.Adopt(QualifierLoc);
2139
2140  DeclarationNameInfo NameInfo
2141    = SemaRef.SubstDeclarationNameInfo(D->getNameInfo(), TemplateArgs);
2142
2143  NamedDecl *UD =
2144    SemaRef.BuildUsingDeclaration(/*Scope*/ 0, D->getAccess(),
2145                                  D->getUsingLoc(), SS, NameInfo, 0,
2146                                  /*instantiation*/ true,
2147                                  /*typename*/ false, SourceLocation());
2148  if (UD)
2149    SemaRef.Context.setInstantiatedFromUsingDecl(cast<UsingDecl>(UD), D);
2150
2151  return UD;
2152}
2153
2154
2155Decl *TemplateDeclInstantiator::VisitClassScopeFunctionSpecializationDecl(
2156                                     ClassScopeFunctionSpecializationDecl *Decl) {
2157  CXXMethodDecl *OldFD = Decl->getSpecialization();
2158  CXXMethodDecl *NewFD = cast<CXXMethodDecl>(VisitCXXMethodDecl(OldFD,
2159                                                                0, true));
2160
2161  LookupResult Previous(SemaRef, NewFD->getNameInfo(), Sema::LookupOrdinaryName,
2162                        Sema::ForRedeclaration);
2163
2164  TemplateArgumentListInfo TemplateArgs;
2165  TemplateArgumentListInfo* TemplateArgsPtr = 0;
2166  if (Decl->hasExplicitTemplateArgs()) {
2167    TemplateArgs = Decl->templateArgs();
2168    TemplateArgsPtr = &TemplateArgs;
2169  }
2170
2171  SemaRef.LookupQualifiedName(Previous, SemaRef.CurContext);
2172  if (SemaRef.CheckFunctionTemplateSpecialization(NewFD, TemplateArgsPtr,
2173                                                  Previous)) {
2174    NewFD->setInvalidDecl();
2175    return NewFD;
2176  }
2177
2178  // Associate the specialization with the pattern.
2179  FunctionDecl *Specialization = cast<FunctionDecl>(Previous.getFoundDecl());
2180  assert(Specialization && "Class scope Specialization is null");
2181  SemaRef.Context.setClassScopeSpecializationPattern(Specialization, OldFD);
2182
2183  return NewFD;
2184}
2185
2186Decl *Sema::SubstDecl(Decl *D, DeclContext *Owner,
2187                      const MultiLevelTemplateArgumentList &TemplateArgs) {
2188  TemplateDeclInstantiator Instantiator(*this, Owner, TemplateArgs);
2189  if (D->isInvalidDecl())
2190    return 0;
2191
2192  return Instantiator.Visit(D);
2193}
2194
2195/// \brief Instantiates a nested template parameter list in the current
2196/// instantiation context.
2197///
2198/// \param L The parameter list to instantiate
2199///
2200/// \returns NULL if there was an error
2201TemplateParameterList *
2202TemplateDeclInstantiator::SubstTemplateParams(TemplateParameterList *L) {
2203  // Get errors for all the parameters before bailing out.
2204  bool Invalid = false;
2205
2206  unsigned N = L->size();
2207  typedef SmallVector<NamedDecl *, 8> ParamVector;
2208  ParamVector Params;
2209  Params.reserve(N);
2210  for (TemplateParameterList::iterator PI = L->begin(), PE = L->end();
2211       PI != PE; ++PI) {
2212    NamedDecl *D = cast_or_null<NamedDecl>(Visit(*PI));
2213    Params.push_back(D);
2214    Invalid = Invalid || !D || D->isInvalidDecl();
2215  }
2216
2217  // Clean up if we had an error.
2218  if (Invalid)
2219    return NULL;
2220
2221  TemplateParameterList *InstL
2222    = TemplateParameterList::Create(SemaRef.Context, L->getTemplateLoc(),
2223                                    L->getLAngleLoc(), &Params.front(), N,
2224                                    L->getRAngleLoc());
2225  return InstL;
2226}
2227
2228/// \brief Instantiate the declaration of a class template partial
2229/// specialization.
2230///
2231/// \param ClassTemplate the (instantiated) class template that is partially
2232// specialized by the instantiation of \p PartialSpec.
2233///
2234/// \param PartialSpec the (uninstantiated) class template partial
2235/// specialization that we are instantiating.
2236///
2237/// \returns The instantiated partial specialization, if successful; otherwise,
2238/// NULL to indicate an error.
2239ClassTemplatePartialSpecializationDecl *
2240TemplateDeclInstantiator::InstantiateClassTemplatePartialSpecialization(
2241                                            ClassTemplateDecl *ClassTemplate,
2242                          ClassTemplatePartialSpecializationDecl *PartialSpec) {
2243  // Create a local instantiation scope for this class template partial
2244  // specialization, which will contain the instantiations of the template
2245  // parameters.
2246  LocalInstantiationScope Scope(SemaRef);
2247
2248  // Substitute into the template parameters of the class template partial
2249  // specialization.
2250  TemplateParameterList *TempParams = PartialSpec->getTemplateParameters();
2251  TemplateParameterList *InstParams = SubstTemplateParams(TempParams);
2252  if (!InstParams)
2253    return 0;
2254
2255  // Substitute into the template arguments of the class template partial
2256  // specialization.
2257  TemplateArgumentListInfo InstTemplateArgs; // no angle locations
2258  if (SemaRef.Subst(PartialSpec->getTemplateArgsAsWritten(),
2259                    PartialSpec->getNumTemplateArgsAsWritten(),
2260                    InstTemplateArgs, TemplateArgs))
2261    return 0;
2262
2263  // Check that the template argument list is well-formed for this
2264  // class template.
2265  SmallVector<TemplateArgument, 4> Converted;
2266  if (SemaRef.CheckTemplateArgumentList(ClassTemplate,
2267                                        PartialSpec->getLocation(),
2268                                        InstTemplateArgs,
2269                                        false,
2270                                        Converted))
2271    return 0;
2272
2273  // Figure out where to insert this class template partial specialization
2274  // in the member template's set of class template partial specializations.
2275  void *InsertPos = 0;
2276  ClassTemplateSpecializationDecl *PrevDecl
2277    = ClassTemplate->findPartialSpecialization(Converted.data(),
2278                                               Converted.size(), InsertPos);
2279
2280  // Build the canonical type that describes the converted template
2281  // arguments of the class template partial specialization.
2282  QualType CanonType
2283    = SemaRef.Context.getTemplateSpecializationType(TemplateName(ClassTemplate),
2284                                                    Converted.data(),
2285                                                    Converted.size());
2286
2287  // Build the fully-sugared type for this class template
2288  // specialization as the user wrote in the specialization
2289  // itself. This means that we'll pretty-print the type retrieved
2290  // from the specialization's declaration the way that the user
2291  // actually wrote the specialization, rather than formatting the
2292  // name based on the "canonical" representation used to store the
2293  // template arguments in the specialization.
2294  TypeSourceInfo *WrittenTy
2295    = SemaRef.Context.getTemplateSpecializationTypeInfo(
2296                                                    TemplateName(ClassTemplate),
2297                                                    PartialSpec->getLocation(),
2298                                                    InstTemplateArgs,
2299                                                    CanonType);
2300
2301  if (PrevDecl) {
2302    // We've already seen a partial specialization with the same template
2303    // parameters and template arguments. This can happen, for example, when
2304    // substituting the outer template arguments ends up causing two
2305    // class template partial specializations of a member class template
2306    // to have identical forms, e.g.,
2307    //
2308    //   template<typename T, typename U>
2309    //   struct Outer {
2310    //     template<typename X, typename Y> struct Inner;
2311    //     template<typename Y> struct Inner<T, Y>;
2312    //     template<typename Y> struct Inner<U, Y>;
2313    //   };
2314    //
2315    //   Outer<int, int> outer; // error: the partial specializations of Inner
2316    //                          // have the same signature.
2317    SemaRef.Diag(PartialSpec->getLocation(), diag::err_partial_spec_redeclared)
2318      << WrittenTy->getType();
2319    SemaRef.Diag(PrevDecl->getLocation(), diag::note_prev_partial_spec_here)
2320      << SemaRef.Context.getTypeDeclType(PrevDecl);
2321    return 0;
2322  }
2323
2324
2325  // Create the class template partial specialization declaration.
2326  ClassTemplatePartialSpecializationDecl *InstPartialSpec
2327    = ClassTemplatePartialSpecializationDecl::Create(SemaRef.Context,
2328                                                     PartialSpec->getTagKind(),
2329                                                     Owner,
2330                                                     PartialSpec->getLocStart(),
2331                                                     PartialSpec->getLocation(),
2332                                                     InstParams,
2333                                                     ClassTemplate,
2334                                                     Converted.data(),
2335                                                     Converted.size(),
2336                                                     InstTemplateArgs,
2337                                                     CanonType,
2338                                                     0,
2339                             ClassTemplate->getNextPartialSpecSequenceNumber());
2340  // Substitute the nested name specifier, if any.
2341  if (SubstQualifier(PartialSpec, InstPartialSpec))
2342    return 0;
2343
2344  InstPartialSpec->setInstantiatedFromMember(PartialSpec);
2345  InstPartialSpec->setTypeAsWritten(WrittenTy);
2346
2347  // Add this partial specialization to the set of class template partial
2348  // specializations.
2349  ClassTemplate->AddPartialSpecialization(InstPartialSpec, /*InsertPos=*/0);
2350  return InstPartialSpec;
2351}
2352
2353TypeSourceInfo*
2354TemplateDeclInstantiator::SubstFunctionType(FunctionDecl *D,
2355                              SmallVectorImpl<ParmVarDecl *> &Params) {
2356  TypeSourceInfo *OldTInfo = D->getTypeSourceInfo();
2357  assert(OldTInfo && "substituting function without type source info");
2358  assert(Params.empty() && "parameter vector is non-empty at start");
2359
2360  CXXRecordDecl *ThisContext = 0;
2361  unsigned ThisTypeQuals = 0;
2362  if (CXXMethodDecl *Method = dyn_cast<CXXMethodDecl>(D)) {
2363    ThisContext = Method->getParent();
2364    ThisTypeQuals = Method->getTypeQualifiers();
2365  }
2366
2367  TypeSourceInfo *NewTInfo
2368    = SemaRef.SubstFunctionDeclType(OldTInfo, TemplateArgs,
2369                                    D->getTypeSpecStartLoc(),
2370                                    D->getDeclName(),
2371                                    ThisContext, ThisTypeQuals);
2372  if (!NewTInfo)
2373    return 0;
2374
2375  if (NewTInfo != OldTInfo) {
2376    // Get parameters from the new type info.
2377    TypeLoc OldTL = OldTInfo->getTypeLoc().IgnoreParens();
2378    if (FunctionProtoTypeLoc OldProtoLoc =
2379            OldTL.getAs<FunctionProtoTypeLoc>()) {
2380      TypeLoc NewTL = NewTInfo->getTypeLoc().IgnoreParens();
2381      FunctionProtoTypeLoc NewProtoLoc = NewTL.castAs<FunctionProtoTypeLoc>();
2382      unsigned NewIdx = 0;
2383      for (unsigned OldIdx = 0, NumOldParams = OldProtoLoc.getNumArgs();
2384           OldIdx != NumOldParams; ++OldIdx) {
2385        ParmVarDecl *OldParam = OldProtoLoc.getArg(OldIdx);
2386        LocalInstantiationScope *Scope = SemaRef.CurrentInstantiationScope;
2387
2388        Optional<unsigned> NumArgumentsInExpansion;
2389        if (OldParam->isParameterPack())
2390          NumArgumentsInExpansion =
2391              SemaRef.getNumArgumentsInExpansion(OldParam->getType(),
2392                                                 TemplateArgs);
2393        if (!NumArgumentsInExpansion) {
2394          // Simple case: normal parameter, or a parameter pack that's
2395          // instantiated to a (still-dependent) parameter pack.
2396          ParmVarDecl *NewParam = NewProtoLoc.getArg(NewIdx++);
2397          Params.push_back(NewParam);
2398          Scope->InstantiatedLocal(OldParam, NewParam);
2399        } else {
2400          // Parameter pack expansion: make the instantiation an argument pack.
2401          Scope->MakeInstantiatedLocalArgPack(OldParam);
2402          for (unsigned I = 0; I != *NumArgumentsInExpansion; ++I) {
2403            ParmVarDecl *NewParam = NewProtoLoc.getArg(NewIdx++);
2404            Params.push_back(NewParam);
2405            Scope->InstantiatedLocalPackArg(OldParam, NewParam);
2406          }
2407        }
2408      }
2409    }
2410  } else {
2411    // The function type itself was not dependent and therefore no
2412    // substitution occurred. However, we still need to instantiate
2413    // the function parameters themselves.
2414    TypeLoc OldTL = OldTInfo->getTypeLoc().IgnoreParens();
2415    if (FunctionProtoTypeLoc OldProtoLoc =
2416            OldTL.getAs<FunctionProtoTypeLoc>()) {
2417      for (unsigned i = 0, i_end = OldProtoLoc.getNumArgs(); i != i_end; ++i) {
2418        ParmVarDecl *Parm = VisitParmVarDecl(OldProtoLoc.getArg(i));
2419        if (!Parm)
2420          return 0;
2421        Params.push_back(Parm);
2422      }
2423    }
2424  }
2425  return NewTInfo;
2426}
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.
2431static void addInstantiatedParametersToScope(Sema &S, FunctionDecl *Function,
2432                                             const FunctionDecl *PatternDecl,
2433                                             LocalInstantiationScope &Scope,
2434                           const MultiLevelTemplateArgumentList &TemplateArgs) {
2435  unsigned FParamIdx = 0;
2436  for (unsigned I = 0, N = PatternDecl->getNumParams(); I != N; ++I) {
2437    const ParmVarDecl *PatternParam = PatternDecl->getParamDecl(I);
2438    if (!PatternParam->isParameterPack()) {
2439      // Simple case: not a parameter pack.
2440      assert(FParamIdx < Function->getNumParams());
2441      ParmVarDecl *FunctionParam = Function->getParamDecl(FParamIdx);
2442      FunctionParam->setDeclName(PatternParam->getDeclName());
2443      Scope.InstantiatedLocal(PatternParam, FunctionParam);
2444      ++FParamIdx;
2445      continue;
2446    }
2447
2448    // Expand the parameter pack.
2449    Scope.MakeInstantiatedLocalArgPack(PatternParam);
2450    Optional<unsigned> NumArgumentsInExpansion
2451      = S.getNumArgumentsInExpansion(PatternParam->getType(), TemplateArgs);
2452    assert(NumArgumentsInExpansion &&
2453           "should only be called when all template arguments are known");
2454    for (unsigned Arg = 0; Arg < *NumArgumentsInExpansion; ++Arg) {
2455      ParmVarDecl *FunctionParam = Function->getParamDecl(FParamIdx);
2456      FunctionParam->setDeclName(PatternParam->getDeclName());
2457      Scope.InstantiatedLocalPackArg(PatternParam, FunctionParam);
2458      ++FParamIdx;
2459    }
2460  }
2461}
2462
2463static void InstantiateExceptionSpec(Sema &SemaRef, FunctionDecl *New,
2464                                     const FunctionProtoType *Proto,
2465                           const MultiLevelTemplateArgumentList &TemplateArgs) {
2466  assert(Proto->getExceptionSpecType() != EST_Uninstantiated);
2467
2468  // C++11 [expr.prim.general]p3:
2469  //   If a declaration declares a member function or member function
2470  //   template of a class X, the expression this is a prvalue of type
2471  //   "pointer to cv-qualifier-seq X" between the optional cv-qualifer-seq
2472  //   and the end of the function-definition, member-declarator, or
2473  //   declarator.
2474  CXXRecordDecl *ThisContext = 0;
2475  unsigned ThisTypeQuals = 0;
2476  if (CXXMethodDecl *Method = dyn_cast<CXXMethodDecl>(New)) {
2477    ThisContext = Method->getParent();
2478    ThisTypeQuals = Method->getTypeQualifiers();
2479  }
2480  Sema::CXXThisScopeRAII ThisScope(SemaRef, ThisContext, ThisTypeQuals,
2481                                   SemaRef.getLangOpts().CPlusPlus11);
2482
2483  // The function has an exception specification or a "noreturn"
2484  // attribute. Substitute into each of the exception types.
2485  SmallVector<QualType, 4> Exceptions;
2486  for (unsigned I = 0, N = Proto->getNumExceptions(); I != N; ++I) {
2487    // FIXME: Poor location information!
2488    if (const PackExpansionType *PackExpansion
2489          = Proto->getExceptionType(I)->getAs<PackExpansionType>()) {
2490      // We have a pack expansion. Instantiate it.
2491      SmallVector<UnexpandedParameterPack, 2> Unexpanded;
2492      SemaRef.collectUnexpandedParameterPacks(PackExpansion->getPattern(),
2493                                              Unexpanded);
2494      assert(!Unexpanded.empty() &&
2495             "Pack expansion without parameter packs?");
2496
2497      bool Expand = false;
2498      bool RetainExpansion = false;
2499      Optional<unsigned> NumExpansions
2500                                        = PackExpansion->getNumExpansions();
2501      if (SemaRef.CheckParameterPacksForExpansion(New->getLocation(),
2502                                                  SourceRange(),
2503                                                  Unexpanded,
2504                                                  TemplateArgs,
2505                                                  Expand,
2506                                                  RetainExpansion,
2507                                                  NumExpansions))
2508        break;
2509
2510      if (!Expand) {
2511        // We can't expand this pack expansion into separate arguments yet;
2512        // just substitute into the pattern and create a new pack expansion
2513        // type.
2514        Sema::ArgumentPackSubstitutionIndexRAII SubstIndex(SemaRef, -1);
2515        QualType T = SemaRef.SubstType(PackExpansion->getPattern(),
2516                                       TemplateArgs,
2517                                     New->getLocation(), New->getDeclName());
2518        if (T.isNull())
2519          break;
2520
2521        T = SemaRef.Context.getPackExpansionType(T, NumExpansions);
2522        Exceptions.push_back(T);
2523        continue;
2524      }
2525
2526      // Substitute into the pack expansion pattern for each template
2527      bool Invalid = false;
2528      for (unsigned ArgIdx = 0; ArgIdx != *NumExpansions; ++ArgIdx) {
2529        Sema::ArgumentPackSubstitutionIndexRAII SubstIndex(SemaRef, ArgIdx);
2530
2531        QualType T = SemaRef.SubstType(PackExpansion->getPattern(),
2532                                       TemplateArgs,
2533                                     New->getLocation(), New->getDeclName());
2534        if (T.isNull()) {
2535          Invalid = true;
2536          break;
2537        }
2538
2539        Exceptions.push_back(T);
2540      }
2541
2542      if (Invalid)
2543        break;
2544
2545      continue;
2546    }
2547
2548    QualType T
2549      = SemaRef.SubstType(Proto->getExceptionType(I), TemplateArgs,
2550                          New->getLocation(), New->getDeclName());
2551    if (T.isNull() ||
2552        SemaRef.CheckSpecifiedExceptionType(T, New->getLocation()))
2553      continue;
2554
2555    Exceptions.push_back(T);
2556  }
2557  Expr *NoexceptExpr = 0;
2558  if (Expr *OldNoexceptExpr = Proto->getNoexceptExpr()) {
2559    EnterExpressionEvaluationContext Unevaluated(SemaRef,
2560                                                 Sema::ConstantEvaluated);
2561    ExprResult E = SemaRef.SubstExpr(OldNoexceptExpr, TemplateArgs);
2562    if (E.isUsable())
2563      E = SemaRef.CheckBooleanCondition(E.get(), E.get()->getLocStart());
2564
2565    if (E.isUsable()) {
2566      NoexceptExpr = E.take();
2567      if (!NoexceptExpr->isTypeDependent() &&
2568          !NoexceptExpr->isValueDependent())
2569        NoexceptExpr
2570          = SemaRef.VerifyIntegerConstantExpression(NoexceptExpr,
2571              0, diag::err_noexcept_needs_constant_expression,
2572              /*AllowFold*/ false).take();
2573    }
2574  }
2575
2576  // Rebuild the function type
2577  const FunctionProtoType *NewProto
2578    = New->getType()->getAs<FunctionProtoType>();
2579  assert(NewProto && "Template instantiation without function prototype?");
2580
2581  FunctionProtoType::ExtProtoInfo EPI = NewProto->getExtProtoInfo();
2582  EPI.ExceptionSpecType = Proto->getExceptionSpecType();
2583  EPI.NumExceptions = Exceptions.size();
2584  EPI.Exceptions = Exceptions.data();
2585  EPI.NoexceptExpr = NoexceptExpr;
2586
2587  New->setType(SemaRef.Context.getFunctionType(NewProto->getResultType(),
2588                                  ArrayRef<QualType>(NewProto->arg_type_begin(),
2589                                                     NewProto->getNumArgs()),
2590                                               EPI));
2591}
2592
2593void Sema::InstantiateExceptionSpec(SourceLocation PointOfInstantiation,
2594                                    FunctionDecl *Decl) {
2595  const FunctionProtoType *Proto = Decl->getType()->castAs<FunctionProtoType>();
2596  if (Proto->getExceptionSpecType() != EST_Uninstantiated)
2597    return;
2598
2599  InstantiatingTemplate Inst(*this, PointOfInstantiation, Decl,
2600                             InstantiatingTemplate::ExceptionSpecification());
2601  if (Inst) {
2602    // We hit the instantiation depth limit. Clear the exception specification
2603    // so that our callers don't have to cope with EST_Uninstantiated.
2604    FunctionProtoType::ExtProtoInfo EPI = Proto->getExtProtoInfo();
2605    EPI.ExceptionSpecType = EST_None;
2606    Decl->setType(Context.getFunctionType(Proto->getResultType(),
2607                                    ArrayRef<QualType>(Proto->arg_type_begin(),
2608                                                       Proto->getNumArgs()),
2609                                          EPI));
2610    return;
2611  }
2612
2613  // Enter the scope of this instantiation. We don't use
2614  // PushDeclContext because we don't have a scope.
2615  Sema::ContextRAII savedContext(*this, Decl);
2616  LocalInstantiationScope Scope(*this);
2617
2618  MultiLevelTemplateArgumentList TemplateArgs =
2619    getTemplateInstantiationArgs(Decl, 0, /*RelativeToPrimary*/true);
2620
2621  FunctionDecl *Template = Proto->getExceptionSpecTemplate();
2622  addInstantiatedParametersToScope(*this, Decl, Template, Scope, TemplateArgs);
2623
2624  ::InstantiateExceptionSpec(*this, Decl,
2625                             Template->getType()->castAs<FunctionProtoType>(),
2626                             TemplateArgs);
2627}
2628
2629/// \brief Initializes the common fields of an instantiation function
2630/// declaration (New) from the corresponding fields of its template (Tmpl).
2631///
2632/// \returns true if there was an error
2633bool
2634TemplateDeclInstantiator::InitFunctionInstantiation(FunctionDecl *New,
2635                                                    FunctionDecl *Tmpl) {
2636  if (Tmpl->isDeleted())
2637    New->setDeletedAsWritten();
2638
2639  // If we are performing substituting explicitly-specified template arguments
2640  // or deduced template arguments into a function template and we reach this
2641  // point, we are now past the point where SFINAE applies and have committed
2642  // to keeping the new function template specialization. We therefore
2643  // convert the active template instantiation for the function template
2644  // into a template instantiation for this specific function template
2645  // specialization, which is not a SFINAE context, so that we diagnose any
2646  // further errors in the declaration itself.
2647  typedef Sema::ActiveTemplateInstantiation ActiveInstType;
2648  ActiveInstType &ActiveInst = SemaRef.ActiveTemplateInstantiations.back();
2649  if (ActiveInst.Kind == ActiveInstType::ExplicitTemplateArgumentSubstitution ||
2650      ActiveInst.Kind == ActiveInstType::DeducedTemplateArgumentSubstitution) {
2651    if (FunctionTemplateDecl *FunTmpl
2652          = dyn_cast<FunctionTemplateDecl>(ActiveInst.Entity)) {
2653      assert(FunTmpl->getTemplatedDecl() == Tmpl &&
2654             "Deduction from the wrong function template?");
2655      (void) FunTmpl;
2656      ActiveInst.Kind = ActiveInstType::TemplateInstantiation;
2657      ActiveInst.Entity = New;
2658    }
2659  }
2660
2661  const FunctionProtoType *Proto = Tmpl->getType()->getAs<FunctionProtoType>();
2662  assert(Proto && "Function template without prototype?");
2663
2664  if (Proto->hasExceptionSpec() || Proto->getNoReturnAttr()) {
2665    FunctionProtoType::ExtProtoInfo EPI = Proto->getExtProtoInfo();
2666
2667    // DR1330: In C++11, defer instantiation of a non-trivial
2668    // exception specification.
2669    if (SemaRef.getLangOpts().CPlusPlus11 &&
2670        EPI.ExceptionSpecType != EST_None &&
2671        EPI.ExceptionSpecType != EST_DynamicNone &&
2672        EPI.ExceptionSpecType != EST_BasicNoexcept) {
2673      FunctionDecl *ExceptionSpecTemplate = Tmpl;
2674      if (EPI.ExceptionSpecType == EST_Uninstantiated)
2675        ExceptionSpecTemplate = EPI.ExceptionSpecTemplate;
2676      assert(EPI.ExceptionSpecType != EST_Unevaluated &&
2677             "instantiating implicitly-declared special member");
2678
2679      // Mark the function has having an uninstantiated exception specification.
2680      const FunctionProtoType *NewProto
2681        = New->getType()->getAs<FunctionProtoType>();
2682      assert(NewProto && "Template instantiation without function prototype?");
2683      EPI = NewProto->getExtProtoInfo();
2684      EPI.ExceptionSpecType = EST_Uninstantiated;
2685      EPI.ExceptionSpecDecl = New;
2686      EPI.ExceptionSpecTemplate = ExceptionSpecTemplate;
2687      New->setType(SemaRef.Context.getFunctionType(NewProto->getResultType(),
2688                                  ArrayRef<QualType>(NewProto->arg_type_begin(),
2689                                                     NewProto->getNumArgs()),
2690                                                   EPI));
2691    } else {
2692      ::InstantiateExceptionSpec(SemaRef, New, Proto, TemplateArgs);
2693    }
2694  }
2695
2696  // Get the definition. Leaves the variable unchanged if undefined.
2697  const FunctionDecl *Definition = Tmpl;
2698  Tmpl->isDefined(Definition);
2699
2700  SemaRef.InstantiateAttrs(TemplateArgs, Definition, New,
2701                           LateAttrs, StartingScope);
2702
2703  return false;
2704}
2705
2706/// \brief Initializes common fields of an instantiated method
2707/// declaration (New) from the corresponding fields of its template
2708/// (Tmpl).
2709///
2710/// \returns true if there was an error
2711bool
2712TemplateDeclInstantiator::InitMethodInstantiation(CXXMethodDecl *New,
2713                                                  CXXMethodDecl *Tmpl) {
2714  if (InitFunctionInstantiation(New, Tmpl))
2715    return true;
2716
2717  New->setAccess(Tmpl->getAccess());
2718  if (Tmpl->isVirtualAsWritten())
2719    New->setVirtualAsWritten(true);
2720
2721  // FIXME: attributes
2722  // FIXME: New needs a pointer to Tmpl
2723  return false;
2724}
2725
2726/// \brief Instantiate the definition of the given function from its
2727/// template.
2728///
2729/// \param PointOfInstantiation the point at which the instantiation was
2730/// required. Note that this is not precisely a "point of instantiation"
2731/// for the function, but it's close.
2732///
2733/// \param Function the already-instantiated declaration of a
2734/// function template specialization or member function of a class template
2735/// specialization.
2736///
2737/// \param Recursive if true, recursively instantiates any functions that
2738/// are required by this instantiation.
2739///
2740/// \param DefinitionRequired if true, then we are performing an explicit
2741/// instantiation where the body of the function is required. Complain if
2742/// there is no such body.
2743void Sema::InstantiateFunctionDefinition(SourceLocation PointOfInstantiation,
2744                                         FunctionDecl *Function,
2745                                         bool Recursive,
2746                                         bool DefinitionRequired) {
2747  if (Function->isInvalidDecl() || Function->isDefined())
2748    return;
2749
2750  // Never instantiate an explicit specialization except if it is a class scope
2751  // explicit specialization.
2752  if (Function->getTemplateSpecializationKind() == TSK_ExplicitSpecialization &&
2753      !Function->getClassScopeSpecializationPattern())
2754    return;
2755
2756  // Find the function body that we'll be substituting.
2757  const FunctionDecl *PatternDecl = Function->getTemplateInstantiationPattern();
2758  assert(PatternDecl && "instantiating a non-template");
2759
2760  Stmt *Pattern = PatternDecl->getBody(PatternDecl);
2761  assert(PatternDecl && "template definition is not a template");
2762  if (!Pattern) {
2763    // Try to find a defaulted definition
2764    PatternDecl->isDefined(PatternDecl);
2765  }
2766  assert(PatternDecl && "template definition is not a template");
2767
2768  // Postpone late parsed template instantiations.
2769  if (PatternDecl->isLateTemplateParsed() &&
2770      !LateTemplateParser) {
2771    PendingInstantiations.push_back(
2772      std::make_pair(Function, PointOfInstantiation));
2773    return;
2774  }
2775
2776  // Call the LateTemplateParser callback if there a need to late parse
2777  // a templated function definition.
2778  if (!Pattern && PatternDecl->isLateTemplateParsed() &&
2779      LateTemplateParser) {
2780    LateTemplateParser(OpaqueParser, PatternDecl);
2781    Pattern = PatternDecl->getBody(PatternDecl);
2782  }
2783
2784  if (!Pattern && !PatternDecl->isDefaulted()) {
2785    if (DefinitionRequired) {
2786      if (Function->getPrimaryTemplate())
2787        Diag(PointOfInstantiation,
2788             diag::err_explicit_instantiation_undefined_func_template)
2789          << Function->getPrimaryTemplate();
2790      else
2791        Diag(PointOfInstantiation,
2792             diag::err_explicit_instantiation_undefined_member)
2793          << 1 << Function->getDeclName() << Function->getDeclContext();
2794
2795      if (PatternDecl)
2796        Diag(PatternDecl->getLocation(),
2797             diag::note_explicit_instantiation_here);
2798      Function->setInvalidDecl();
2799    } else if (Function->getTemplateSpecializationKind()
2800                 == TSK_ExplicitInstantiationDefinition) {
2801      PendingInstantiations.push_back(
2802        std::make_pair(Function, PointOfInstantiation));
2803    }
2804
2805    return;
2806  }
2807
2808  // C++0x [temp.explicit]p9:
2809  //   Except for inline functions, other explicit instantiation declarations
2810  //   have the effect of suppressing the implicit instantiation of the entity
2811  //   to which they refer.
2812  if (Function->getTemplateSpecializationKind()
2813        == TSK_ExplicitInstantiationDeclaration &&
2814      !PatternDecl->isInlined())
2815    return;
2816
2817  if (PatternDecl->isInlined())
2818    Function->setImplicitlyInline();
2819
2820  InstantiatingTemplate Inst(*this, PointOfInstantiation, Function);
2821  if (Inst)
2822    return;
2823
2824  // Copy the inner loc start from the pattern.
2825  Function->setInnerLocStart(PatternDecl->getInnerLocStart());
2826
2827  // If we're performing recursive template instantiation, create our own
2828  // queue of pending implicit instantiations that we will instantiate later,
2829  // while we're still within our own instantiation context.
2830  SmallVector<VTableUse, 16> SavedVTableUses;
2831  std::deque<PendingImplicitInstantiation> SavedPendingInstantiations;
2832  if (Recursive) {
2833    VTableUses.swap(SavedVTableUses);
2834    PendingInstantiations.swap(SavedPendingInstantiations);
2835  }
2836
2837  EnterExpressionEvaluationContext EvalContext(*this,
2838                                               Sema::PotentiallyEvaluated);
2839
2840  // Introduce a new scope where local variable instantiations will be
2841  // recorded, unless we're actually a member function within a local
2842  // class, in which case we need to merge our results with the parent
2843  // scope (of the enclosing function).
2844  bool MergeWithParentScope = false;
2845  if (CXXRecordDecl *Rec = dyn_cast<CXXRecordDecl>(Function->getDeclContext()))
2846    MergeWithParentScope = Rec->isLocalClass();
2847
2848  LocalInstantiationScope Scope(*this, MergeWithParentScope);
2849
2850  if (PatternDecl->isDefaulted())
2851    SetDeclDefaulted(Function, PatternDecl->getLocation());
2852  else {
2853    ActOnStartOfFunctionDef(0, Function);
2854
2855    // Enter the scope of this instantiation. We don't use
2856    // PushDeclContext because we don't have a scope.
2857    Sema::ContextRAII savedContext(*this, Function);
2858
2859    MultiLevelTemplateArgumentList TemplateArgs =
2860      getTemplateInstantiationArgs(Function, 0, false, PatternDecl);
2861
2862    addInstantiatedParametersToScope(*this, Function, PatternDecl, Scope,
2863                                     TemplateArgs);
2864
2865    // If this is a constructor, instantiate the member initializers.
2866    if (const CXXConstructorDecl *Ctor =
2867          dyn_cast<CXXConstructorDecl>(PatternDecl)) {
2868      InstantiateMemInitializers(cast<CXXConstructorDecl>(Function), Ctor,
2869                                 TemplateArgs);
2870    }
2871
2872    // Instantiate the function body.
2873    StmtResult Body = SubstStmt(Pattern, TemplateArgs);
2874
2875    if (Body.isInvalid())
2876      Function->setInvalidDecl();
2877
2878    ActOnFinishFunctionBody(Function, Body.get(),
2879                            /*IsInstantiation=*/true);
2880
2881    PerformDependentDiagnostics(PatternDecl, TemplateArgs);
2882
2883    savedContext.pop();
2884  }
2885
2886  DeclGroupRef DG(Function);
2887  Consumer.HandleTopLevelDecl(DG);
2888
2889  // This class may have local implicit instantiations that need to be
2890  // instantiation within this scope.
2891  PerformPendingInstantiations(/*LocalOnly=*/true);
2892  Scope.Exit();
2893
2894  if (Recursive) {
2895    // Define any pending vtables.
2896    DefineUsedVTables();
2897
2898    // Instantiate any pending implicit instantiations found during the
2899    // instantiation of this template.
2900    PerformPendingInstantiations();
2901
2902    // Restore the set of pending vtables.
2903    assert(VTableUses.empty() &&
2904           "VTableUses should be empty before it is discarded.");
2905    VTableUses.swap(SavedVTableUses);
2906
2907    // Restore the set of pending implicit instantiations.
2908    assert(PendingInstantiations.empty() &&
2909           "PendingInstantiations should be empty before it is discarded.");
2910    PendingInstantiations.swap(SavedPendingInstantiations);
2911  }
2912}
2913
2914/// \brief Instantiate the definition of the given variable from its
2915/// template.
2916///
2917/// \param PointOfInstantiation the point at which the instantiation was
2918/// required. Note that this is not precisely a "point of instantiation"
2919/// for the function, but it's close.
2920///
2921/// \param Var the already-instantiated declaration of a static member
2922/// variable of a class template specialization.
2923///
2924/// \param Recursive if true, recursively instantiates any functions that
2925/// are required by this instantiation.
2926///
2927/// \param DefinitionRequired if true, then we are performing an explicit
2928/// instantiation where an out-of-line definition of the member variable
2929/// is required. Complain if there is no such definition.
2930void Sema::InstantiateStaticDataMemberDefinition(
2931                                          SourceLocation PointOfInstantiation,
2932                                                 VarDecl *Var,
2933                                                 bool Recursive,
2934                                                 bool DefinitionRequired) {
2935  if (Var->isInvalidDecl())
2936    return;
2937
2938  // Find the out-of-line definition of this static data member.
2939  VarDecl *Def = Var->getInstantiatedFromStaticDataMember();
2940  assert(Def && "This data member was not instantiated from a template?");
2941  assert(Def->isStaticDataMember() && "Not a static data member?");
2942  Def = Def->getOutOfLineDefinition();
2943
2944  if (!Def) {
2945    // We did not find an out-of-line definition of this static data member,
2946    // so we won't perform any instantiation. Rather, we rely on the user to
2947    // instantiate this definition (or provide a specialization for it) in
2948    // another translation unit.
2949    if (DefinitionRequired) {
2950      Def = Var->getInstantiatedFromStaticDataMember();
2951      Diag(PointOfInstantiation,
2952           diag::err_explicit_instantiation_undefined_member)
2953        << 2 << Var->getDeclName() << Var->getDeclContext();
2954      Diag(Def->getLocation(), diag::note_explicit_instantiation_here);
2955    } else if (Var->getTemplateSpecializationKind()
2956                 == TSK_ExplicitInstantiationDefinition) {
2957      PendingInstantiations.push_back(
2958        std::make_pair(Var, PointOfInstantiation));
2959    }
2960
2961    return;
2962  }
2963
2964  TemplateSpecializationKind TSK = Var->getTemplateSpecializationKind();
2965
2966  // Never instantiate an explicit specialization.
2967  if (TSK == TSK_ExplicitSpecialization)
2968    return;
2969
2970  // C++0x [temp.explicit]p9:
2971  //   Except for inline functions, other explicit instantiation declarations
2972  //   have the effect of suppressing the implicit instantiation of the entity
2973  //   to which they refer.
2974  if (TSK == TSK_ExplicitInstantiationDeclaration)
2975    return;
2976
2977  // Make sure to pass the instantiated variable to the consumer at the end.
2978  struct PassToConsumerRAII {
2979    ASTConsumer &Consumer;
2980    VarDecl *Var;
2981
2982    PassToConsumerRAII(ASTConsumer &Consumer, VarDecl *Var)
2983      : Consumer(Consumer), Var(Var) { }
2984
2985    ~PassToConsumerRAII() {
2986      Consumer.HandleCXXStaticMemberVarInstantiation(Var);
2987    }
2988  } PassToConsumerRAII(Consumer, Var);
2989
2990  // If we already have a definition, we're done.
2991  if (VarDecl *Def = Var->getDefinition()) {
2992    // We may be explicitly instantiating something we've already implicitly
2993    // instantiated.
2994    Def->setTemplateSpecializationKind(Var->getTemplateSpecializationKind(),
2995                                       PointOfInstantiation);
2996    return;
2997  }
2998
2999  InstantiatingTemplate Inst(*this, PointOfInstantiation, Var);
3000  if (Inst)
3001    return;
3002
3003  // If we're performing recursive template instantiation, create our own
3004  // queue of pending implicit instantiations that we will instantiate later,
3005  // while we're still within our own instantiation context.
3006  SmallVector<VTableUse, 16> SavedVTableUses;
3007  std::deque<PendingImplicitInstantiation> SavedPendingInstantiations;
3008  if (Recursive) {
3009    VTableUses.swap(SavedVTableUses);
3010    PendingInstantiations.swap(SavedPendingInstantiations);
3011  }
3012
3013  // Enter the scope of this instantiation. We don't use
3014  // PushDeclContext because we don't have a scope.
3015  ContextRAII previousContext(*this, Var->getDeclContext());
3016  LocalInstantiationScope Local(*this);
3017
3018  VarDecl *OldVar = Var;
3019  Var = cast_or_null<VarDecl>(SubstDecl(Def, Var->getDeclContext(),
3020                                        getTemplateInstantiationArgs(Var)));
3021
3022  previousContext.pop();
3023
3024  if (Var) {
3025    PassToConsumerRAII.Var = Var;
3026    MemberSpecializationInfo *MSInfo = OldVar->getMemberSpecializationInfo();
3027    assert(MSInfo && "Missing member specialization information?");
3028    Var->setTemplateSpecializationKind(MSInfo->getTemplateSpecializationKind(),
3029                                       MSInfo->getPointOfInstantiation());
3030  }
3031  Local.Exit();
3032
3033  if (Recursive) {
3034    // Define any newly required vtables.
3035    DefineUsedVTables();
3036
3037    // Instantiate any pending implicit instantiations found during the
3038    // instantiation of this template.
3039    PerformPendingInstantiations();
3040
3041    // Restore the set of pending vtables.
3042    assert(VTableUses.empty() &&
3043           "VTableUses should be empty before it is discarded, "
3044           "while instantiating static data member.");
3045    VTableUses.swap(SavedVTableUses);
3046
3047    // Restore the set of pending implicit instantiations.
3048    assert(PendingInstantiations.empty() &&
3049           "PendingInstantiations should be empty before it is discarded, "
3050           "while instantiating static data member.");
3051    PendingInstantiations.swap(SavedPendingInstantiations);
3052  }
3053}
3054
3055void
3056Sema::InstantiateMemInitializers(CXXConstructorDecl *New,
3057                                 const CXXConstructorDecl *Tmpl,
3058                           const MultiLevelTemplateArgumentList &TemplateArgs) {
3059
3060  SmallVector<CXXCtorInitializer*, 4> NewInits;
3061  bool AnyErrors = Tmpl->isInvalidDecl();
3062
3063  // Instantiate all the initializers.
3064  for (CXXConstructorDecl::init_const_iterator Inits = Tmpl->init_begin(),
3065                                            InitsEnd = Tmpl->init_end();
3066       Inits != InitsEnd; ++Inits) {
3067    CXXCtorInitializer *Init = *Inits;
3068
3069    // Only instantiate written initializers, let Sema re-construct implicit
3070    // ones.
3071    if (!Init->isWritten())
3072      continue;
3073
3074    SourceLocation EllipsisLoc;
3075
3076    if (Init->isPackExpansion()) {
3077      // This is a pack expansion. We should expand it now.
3078      TypeLoc BaseTL = Init->getTypeSourceInfo()->getTypeLoc();
3079      SmallVector<UnexpandedParameterPack, 2> Unexpanded;
3080      collectUnexpandedParameterPacks(BaseTL, Unexpanded);
3081      bool ShouldExpand = false;
3082      bool RetainExpansion = false;
3083      Optional<unsigned> NumExpansions;
3084      if (CheckParameterPacksForExpansion(Init->getEllipsisLoc(),
3085                                          BaseTL.getSourceRange(),
3086                                          Unexpanded,
3087                                          TemplateArgs, ShouldExpand,
3088                                          RetainExpansion,
3089                                          NumExpansions)) {
3090        AnyErrors = true;
3091        New->setInvalidDecl();
3092        continue;
3093      }
3094      assert(ShouldExpand && "Partial instantiation of base initializer?");
3095
3096      // Loop over all of the arguments in the argument pack(s),
3097      for (unsigned I = 0; I != *NumExpansions; ++I) {
3098        Sema::ArgumentPackSubstitutionIndexRAII SubstIndex(*this, I);
3099
3100        // Instantiate the initializer.
3101        ExprResult TempInit = SubstInitializer(Init->getInit(), TemplateArgs,
3102                                               /*CXXDirectInit=*/true);
3103        if (TempInit.isInvalid()) {
3104          AnyErrors = true;
3105          break;
3106        }
3107
3108        // Instantiate the base type.
3109        TypeSourceInfo *BaseTInfo = SubstType(Init->getTypeSourceInfo(),
3110                                              TemplateArgs,
3111                                              Init->getSourceLocation(),
3112                                              New->getDeclName());
3113        if (!BaseTInfo) {
3114          AnyErrors = true;
3115          break;
3116        }
3117
3118        // Build the initializer.
3119        MemInitResult NewInit = BuildBaseInitializer(BaseTInfo->getType(),
3120                                                     BaseTInfo, TempInit.take(),
3121                                                     New->getParent(),
3122                                                     SourceLocation());
3123        if (NewInit.isInvalid()) {
3124          AnyErrors = true;
3125          break;
3126        }
3127
3128        NewInits.push_back(NewInit.get());
3129      }
3130
3131      continue;
3132    }
3133
3134    // Instantiate the initializer.
3135    ExprResult TempInit = SubstInitializer(Init->getInit(), TemplateArgs,
3136                                           /*CXXDirectInit=*/true);
3137    if (TempInit.isInvalid()) {
3138      AnyErrors = true;
3139      continue;
3140    }
3141
3142    MemInitResult NewInit;
3143    if (Init->isDelegatingInitializer() || Init->isBaseInitializer()) {
3144      TypeSourceInfo *TInfo = SubstType(Init->getTypeSourceInfo(),
3145                                        TemplateArgs,
3146                                        Init->getSourceLocation(),
3147                                        New->getDeclName());
3148      if (!TInfo) {
3149        AnyErrors = true;
3150        New->setInvalidDecl();
3151        continue;
3152      }
3153
3154      if (Init->isBaseInitializer())
3155        NewInit = BuildBaseInitializer(TInfo->getType(), TInfo, TempInit.take(),
3156                                       New->getParent(), EllipsisLoc);
3157      else
3158        NewInit = BuildDelegatingInitializer(TInfo, TempInit.take(),
3159                                  cast<CXXRecordDecl>(CurContext->getParent()));
3160    } else if (Init->isMemberInitializer()) {
3161      FieldDecl *Member = cast_or_null<FieldDecl>(FindInstantiatedDecl(
3162                                                     Init->getMemberLocation(),
3163                                                     Init->getMember(),
3164                                                     TemplateArgs));
3165      if (!Member) {
3166        AnyErrors = true;
3167        New->setInvalidDecl();
3168        continue;
3169      }
3170
3171      NewInit = BuildMemberInitializer(Member, TempInit.take(),
3172                                       Init->getSourceLocation());
3173    } else if (Init->isIndirectMemberInitializer()) {
3174      IndirectFieldDecl *IndirectMember =
3175         cast_or_null<IndirectFieldDecl>(FindInstantiatedDecl(
3176                                 Init->getMemberLocation(),
3177                                 Init->getIndirectMember(), TemplateArgs));
3178
3179      if (!IndirectMember) {
3180        AnyErrors = true;
3181        New->setInvalidDecl();
3182        continue;
3183      }
3184
3185      NewInit = BuildMemberInitializer(IndirectMember, TempInit.take(),
3186                                       Init->getSourceLocation());
3187    }
3188
3189    if (NewInit.isInvalid()) {
3190      AnyErrors = true;
3191      New->setInvalidDecl();
3192    } else {
3193      NewInits.push_back(NewInit.get());
3194    }
3195  }
3196
3197  // Assign all the initializers to the new constructor.
3198  ActOnMemInitializers(New,
3199                       /*FIXME: ColonLoc */
3200                       SourceLocation(),
3201                       NewInits,
3202                       AnyErrors);
3203}
3204
3205// TODO: this could be templated if the various decl types used the
3206// same method name.
3207static bool isInstantiationOf(ClassTemplateDecl *Pattern,
3208                              ClassTemplateDecl *Instance) {
3209  Pattern = Pattern->getCanonicalDecl();
3210
3211  do {
3212    Instance = Instance->getCanonicalDecl();
3213    if (Pattern == Instance) return true;
3214    Instance = Instance->getInstantiatedFromMemberTemplate();
3215  } while (Instance);
3216
3217  return false;
3218}
3219
3220static bool isInstantiationOf(FunctionTemplateDecl *Pattern,
3221                              FunctionTemplateDecl *Instance) {
3222  Pattern = Pattern->getCanonicalDecl();
3223
3224  do {
3225    Instance = Instance->getCanonicalDecl();
3226    if (Pattern == Instance) return true;
3227    Instance = Instance->getInstantiatedFromMemberTemplate();
3228  } while (Instance);
3229
3230  return false;
3231}
3232
3233static bool
3234isInstantiationOf(ClassTemplatePartialSpecializationDecl *Pattern,
3235                  ClassTemplatePartialSpecializationDecl *Instance) {
3236  Pattern
3237    = cast<ClassTemplatePartialSpecializationDecl>(Pattern->getCanonicalDecl());
3238  do {
3239    Instance = cast<ClassTemplatePartialSpecializationDecl>(
3240                                                Instance->getCanonicalDecl());
3241    if (Pattern == Instance)
3242      return true;
3243    Instance = Instance->getInstantiatedFromMember();
3244  } while (Instance);
3245
3246  return false;
3247}
3248
3249static bool isInstantiationOf(CXXRecordDecl *Pattern,
3250                              CXXRecordDecl *Instance) {
3251  Pattern = Pattern->getCanonicalDecl();
3252
3253  do {
3254    Instance = Instance->getCanonicalDecl();
3255    if (Pattern == Instance) return true;
3256    Instance = Instance->getInstantiatedFromMemberClass();
3257  } while (Instance);
3258
3259  return false;
3260}
3261
3262static bool isInstantiationOf(FunctionDecl *Pattern,
3263                              FunctionDecl *Instance) {
3264  Pattern = Pattern->getCanonicalDecl();
3265
3266  do {
3267    Instance = Instance->getCanonicalDecl();
3268    if (Pattern == Instance) return true;
3269    Instance = Instance->getInstantiatedFromMemberFunction();
3270  } while (Instance);
3271
3272  return false;
3273}
3274
3275static bool isInstantiationOf(EnumDecl *Pattern,
3276                              EnumDecl *Instance) {
3277  Pattern = Pattern->getCanonicalDecl();
3278
3279  do {
3280    Instance = Instance->getCanonicalDecl();
3281    if (Pattern == Instance) return true;
3282    Instance = Instance->getInstantiatedFromMemberEnum();
3283  } while (Instance);
3284
3285  return false;
3286}
3287
3288static bool isInstantiationOf(UsingShadowDecl *Pattern,
3289                              UsingShadowDecl *Instance,
3290                              ASTContext &C) {
3291  return C.getInstantiatedFromUsingShadowDecl(Instance) == Pattern;
3292}
3293
3294static bool isInstantiationOf(UsingDecl *Pattern,
3295                              UsingDecl *Instance,
3296                              ASTContext &C) {
3297  return C.getInstantiatedFromUsingDecl(Instance) == Pattern;
3298}
3299
3300static bool isInstantiationOf(UnresolvedUsingValueDecl *Pattern,
3301                              UsingDecl *Instance,
3302                              ASTContext &C) {
3303  return C.getInstantiatedFromUsingDecl(Instance) == Pattern;
3304}
3305
3306static bool isInstantiationOf(UnresolvedUsingTypenameDecl *Pattern,
3307                              UsingDecl *Instance,
3308                              ASTContext &C) {
3309  return C.getInstantiatedFromUsingDecl(Instance) == Pattern;
3310}
3311
3312static bool isInstantiationOfStaticDataMember(VarDecl *Pattern,
3313                                              VarDecl *Instance) {
3314  assert(Instance->isStaticDataMember());
3315
3316  Pattern = Pattern->getCanonicalDecl();
3317
3318  do {
3319    Instance = Instance->getCanonicalDecl();
3320    if (Pattern == Instance) return true;
3321    Instance = Instance->getInstantiatedFromStaticDataMember();
3322  } while (Instance);
3323
3324  return false;
3325}
3326
3327// Other is the prospective instantiation
3328// D is the prospective pattern
3329static bool isInstantiationOf(ASTContext &Ctx, NamedDecl *D, Decl *Other) {
3330  if (D->getKind() != Other->getKind()) {
3331    if (UnresolvedUsingTypenameDecl *UUD
3332          = dyn_cast<UnresolvedUsingTypenameDecl>(D)) {
3333      if (UsingDecl *UD = dyn_cast<UsingDecl>(Other)) {
3334        return isInstantiationOf(UUD, UD, Ctx);
3335      }
3336    }
3337
3338    if (UnresolvedUsingValueDecl *UUD
3339          = dyn_cast<UnresolvedUsingValueDecl>(D)) {
3340      if (UsingDecl *UD = dyn_cast<UsingDecl>(Other)) {
3341        return isInstantiationOf(UUD, UD, Ctx);
3342      }
3343    }
3344
3345    return false;
3346  }
3347
3348  if (CXXRecordDecl *Record = dyn_cast<CXXRecordDecl>(Other))
3349    return isInstantiationOf(cast<CXXRecordDecl>(D), Record);
3350
3351  if (FunctionDecl *Function = dyn_cast<FunctionDecl>(Other))
3352    return isInstantiationOf(cast<FunctionDecl>(D), Function);
3353
3354  if (EnumDecl *Enum = dyn_cast<EnumDecl>(Other))
3355    return isInstantiationOf(cast<EnumDecl>(D), Enum);
3356
3357  if (VarDecl *Var = dyn_cast<VarDecl>(Other))
3358    if (Var->isStaticDataMember())
3359      return isInstantiationOfStaticDataMember(cast<VarDecl>(D), Var);
3360
3361  if (ClassTemplateDecl *Temp = dyn_cast<ClassTemplateDecl>(Other))
3362    return isInstantiationOf(cast<ClassTemplateDecl>(D), Temp);
3363
3364  if (FunctionTemplateDecl *Temp = dyn_cast<FunctionTemplateDecl>(Other))
3365    return isInstantiationOf(cast<FunctionTemplateDecl>(D), Temp);
3366
3367  if (ClassTemplatePartialSpecializationDecl *PartialSpec
3368        = dyn_cast<ClassTemplatePartialSpecializationDecl>(Other))
3369    return isInstantiationOf(cast<ClassTemplatePartialSpecializationDecl>(D),
3370                             PartialSpec);
3371
3372  if (FieldDecl *Field = dyn_cast<FieldDecl>(Other)) {
3373    if (!Field->getDeclName()) {
3374      // This is an unnamed field.
3375      return Ctx.getInstantiatedFromUnnamedFieldDecl(Field) ==
3376        cast<FieldDecl>(D);
3377    }
3378  }
3379
3380  if (UsingDecl *Using = dyn_cast<UsingDecl>(Other))
3381    return isInstantiationOf(cast<UsingDecl>(D), Using, Ctx);
3382
3383  if (UsingShadowDecl *Shadow = dyn_cast<UsingShadowDecl>(Other))
3384    return isInstantiationOf(cast<UsingShadowDecl>(D), Shadow, Ctx);
3385
3386  return D->getDeclName() && isa<NamedDecl>(Other) &&
3387    D->getDeclName() == cast<NamedDecl>(Other)->getDeclName();
3388}
3389
3390template<typename ForwardIterator>
3391static NamedDecl *findInstantiationOf(ASTContext &Ctx,
3392                                      NamedDecl *D,
3393                                      ForwardIterator first,
3394                                      ForwardIterator last) {
3395  for (; first != last; ++first)
3396    if (isInstantiationOf(Ctx, D, *first))
3397      return cast<NamedDecl>(*first);
3398
3399  return 0;
3400}
3401
3402/// \brief Finds the instantiation of the given declaration context
3403/// within the current instantiation.
3404///
3405/// \returns NULL if there was an error
3406DeclContext *Sema::FindInstantiatedContext(SourceLocation Loc, DeclContext* DC,
3407                          const MultiLevelTemplateArgumentList &TemplateArgs) {
3408  if (NamedDecl *D = dyn_cast<NamedDecl>(DC)) {
3409    Decl* ID = FindInstantiatedDecl(Loc, D, TemplateArgs);
3410    return cast_or_null<DeclContext>(ID);
3411  } else return DC;
3412}
3413
3414/// \brief Find the instantiation of the given declaration within the
3415/// current instantiation.
3416///
3417/// This routine is intended to be used when \p D is a declaration
3418/// referenced from within a template, that needs to mapped into the
3419/// corresponding declaration within an instantiation. For example,
3420/// given:
3421///
3422/// \code
3423/// template<typename T>
3424/// struct X {
3425///   enum Kind {
3426///     KnownValue = sizeof(T)
3427///   };
3428///
3429///   bool getKind() const { return KnownValue; }
3430/// };
3431///
3432/// template struct X<int>;
3433/// \endcode
3434///
3435/// In the instantiation of X<int>::getKind(), we need to map the
3436/// EnumConstantDecl for KnownValue (which refers to
3437/// X<T>::\<Kind>\::KnownValue) to its instantiation
3438/// (X<int>::\<Kind>\::KnownValue). InstantiateCurrentDeclRef() performs
3439/// this mapping from within the instantiation of X<int>.
3440NamedDecl *Sema::FindInstantiatedDecl(SourceLocation Loc, NamedDecl *D,
3441                          const MultiLevelTemplateArgumentList &TemplateArgs) {
3442  DeclContext *ParentDC = D->getDeclContext();
3443  if (isa<ParmVarDecl>(D) || isa<NonTypeTemplateParmDecl>(D) ||
3444      isa<TemplateTypeParmDecl>(D) || isa<TemplateTemplateParmDecl>(D) ||
3445      (ParentDC->isFunctionOrMethod() && ParentDC->isDependentContext()) ||
3446      (isa<CXXRecordDecl>(D) && cast<CXXRecordDecl>(D)->isLambda())) {
3447    // D is a local of some kind. Look into the map of local
3448    // declarations to their instantiations.
3449    typedef LocalInstantiationScope::DeclArgumentPack DeclArgumentPack;
3450    llvm::PointerUnion<Decl *, DeclArgumentPack *> *Found
3451      = CurrentInstantiationScope->findInstantiationOf(D);
3452
3453    if (Found) {
3454      if (Decl *FD = Found->dyn_cast<Decl *>())
3455        return cast<NamedDecl>(FD);
3456
3457      int PackIdx = ArgumentPackSubstitutionIndex;
3458      assert(PackIdx != -1 && "found declaration pack but not pack expanding");
3459      return cast<NamedDecl>((*Found->get<DeclArgumentPack *>())[PackIdx]);
3460    }
3461
3462    // If we didn't find the decl, then we must have a label decl that hasn't
3463    // been found yet.  Lazily instantiate it and return it now.
3464    assert(isa<LabelDecl>(D));
3465
3466    Decl *Inst = SubstDecl(D, CurContext, TemplateArgs);
3467    assert(Inst && "Failed to instantiate label??");
3468
3469    CurrentInstantiationScope->InstantiatedLocal(D, Inst);
3470    return cast<LabelDecl>(Inst);
3471  }
3472
3473  if (CXXRecordDecl *Record = dyn_cast<CXXRecordDecl>(D)) {
3474    if (!Record->isDependentContext())
3475      return D;
3476
3477    // Determine whether this record is the "templated" declaration describing
3478    // a class template or class template partial specialization.
3479    ClassTemplateDecl *ClassTemplate = Record->getDescribedClassTemplate();
3480    if (ClassTemplate)
3481      ClassTemplate = ClassTemplate->getCanonicalDecl();
3482    else if (ClassTemplatePartialSpecializationDecl *PartialSpec
3483               = dyn_cast<ClassTemplatePartialSpecializationDecl>(Record))
3484      ClassTemplate = PartialSpec->getSpecializedTemplate()->getCanonicalDecl();
3485
3486    // Walk the current context to find either the record or an instantiation of
3487    // it.
3488    DeclContext *DC = CurContext;
3489    while (!DC->isFileContext()) {
3490      // If we're performing substitution while we're inside the template
3491      // definition, we'll find our own context. We're done.
3492      if (DC->Equals(Record))
3493        return Record;
3494
3495      if (CXXRecordDecl *InstRecord = dyn_cast<CXXRecordDecl>(DC)) {
3496        // Check whether we're in the process of instantiating a class template
3497        // specialization of the template we're mapping.
3498        if (ClassTemplateSpecializationDecl *InstSpec
3499                      = dyn_cast<ClassTemplateSpecializationDecl>(InstRecord)){
3500          ClassTemplateDecl *SpecTemplate = InstSpec->getSpecializedTemplate();
3501          if (ClassTemplate && isInstantiationOf(ClassTemplate, SpecTemplate))
3502            return InstRecord;
3503        }
3504
3505        // Check whether we're in the process of instantiating a member class.
3506        if (isInstantiationOf(Record, InstRecord))
3507          return InstRecord;
3508      }
3509
3510
3511      // Move to the outer template scope.
3512      if (FunctionDecl *FD = dyn_cast<FunctionDecl>(DC)) {
3513        if (FD->getFriendObjectKind() && FD->getDeclContext()->isFileContext()){
3514          DC = FD->getLexicalDeclContext();
3515          continue;
3516        }
3517      }
3518
3519      DC = DC->getParent();
3520    }
3521
3522    // Fall through to deal with other dependent record types (e.g.,
3523    // anonymous unions in class templates).
3524  }
3525
3526  if (!ParentDC->isDependentContext())
3527    return D;
3528
3529  ParentDC = FindInstantiatedContext(Loc, ParentDC, TemplateArgs);
3530  if (!ParentDC)
3531    return 0;
3532
3533  if (ParentDC != D->getDeclContext()) {
3534    // We performed some kind of instantiation in the parent context,
3535    // so now we need to look into the instantiated parent context to
3536    // find the instantiation of the declaration D.
3537
3538    // If our context used to be dependent, we may need to instantiate
3539    // it before performing lookup into that context.
3540    bool IsBeingInstantiated = false;
3541    if (CXXRecordDecl *Spec = dyn_cast<CXXRecordDecl>(ParentDC)) {
3542      if (!Spec->isDependentContext()) {
3543        QualType T = Context.getTypeDeclType(Spec);
3544        const RecordType *Tag = T->getAs<RecordType>();
3545        assert(Tag && "type of non-dependent record is not a RecordType");
3546        if (Tag->isBeingDefined())
3547          IsBeingInstantiated = true;
3548        if (!Tag->isBeingDefined() &&
3549            RequireCompleteType(Loc, T, diag::err_incomplete_type))
3550          return 0;
3551
3552        ParentDC = Tag->getDecl();
3553      }
3554    }
3555
3556    NamedDecl *Result = 0;
3557    if (D->getDeclName()) {
3558      DeclContext::lookup_result Found = ParentDC->lookup(D->getDeclName());
3559      Result = findInstantiationOf(Context, D, Found.begin(), Found.end());
3560    } else {
3561      // Since we don't have a name for the entity we're looking for,
3562      // our only option is to walk through all of the declarations to
3563      // find that name. This will occur in a few cases:
3564      //
3565      //   - anonymous struct/union within a template
3566      //   - unnamed class/struct/union/enum within a template
3567      //
3568      // FIXME: Find a better way to find these instantiations!
3569      Result = findInstantiationOf(Context, D,
3570                                   ParentDC->decls_begin(),
3571                                   ParentDC->decls_end());
3572    }
3573
3574    if (!Result) {
3575      if (isa<UsingShadowDecl>(D)) {
3576        // UsingShadowDecls can instantiate to nothing because of using hiding.
3577      } else if (Diags.hasErrorOccurred()) {
3578        // We've already complained about something, so most likely this
3579        // declaration failed to instantiate. There's no point in complaining
3580        // further, since this is normal in invalid code.
3581      } else if (IsBeingInstantiated) {
3582        // The class in which this member exists is currently being
3583        // instantiated, and we haven't gotten around to instantiating this
3584        // member yet. This can happen when the code uses forward declarations
3585        // of member classes, and introduces ordering dependencies via
3586        // template instantiation.
3587        Diag(Loc, diag::err_member_not_yet_instantiated)
3588          << D->getDeclName()
3589          << Context.getTypeDeclType(cast<CXXRecordDecl>(ParentDC));
3590        Diag(D->getLocation(), diag::note_non_instantiated_member_here);
3591      } else if (EnumConstantDecl *ED = dyn_cast<EnumConstantDecl>(D)) {
3592        // This enumeration constant was found when the template was defined,
3593        // but can't be found in the instantiation. This can happen if an
3594        // unscoped enumeration member is explicitly specialized.
3595        EnumDecl *Enum = cast<EnumDecl>(ED->getLexicalDeclContext());
3596        EnumDecl *Spec = cast<EnumDecl>(FindInstantiatedDecl(Loc, Enum,
3597                                                             TemplateArgs));
3598        assert(Spec->getTemplateSpecializationKind() ==
3599                 TSK_ExplicitSpecialization);
3600        Diag(Loc, diag::err_enumerator_does_not_exist)
3601          << D->getDeclName()
3602          << Context.getTypeDeclType(cast<TypeDecl>(Spec->getDeclContext()));
3603        Diag(Spec->getLocation(), diag::note_enum_specialized_here)
3604          << Context.getTypeDeclType(Spec);
3605      } else {
3606        // We should have found something, but didn't.
3607        llvm_unreachable("Unable to find instantiation of declaration!");
3608      }
3609    }
3610
3611    D = Result;
3612  }
3613
3614  return D;
3615}
3616
3617/// \brief Performs template instantiation for all implicit template
3618/// instantiations we have seen until this point.
3619void Sema::PerformPendingInstantiations(bool LocalOnly) {
3620  // Load pending instantiations from the external source.
3621  if (!LocalOnly && ExternalSource) {
3622    SmallVector<PendingImplicitInstantiation, 4> Pending;
3623    ExternalSource->ReadPendingInstantiations(Pending);
3624    PendingInstantiations.insert(PendingInstantiations.begin(),
3625                                 Pending.begin(), Pending.end());
3626  }
3627
3628  while (!PendingLocalImplicitInstantiations.empty() ||
3629         (!LocalOnly && !PendingInstantiations.empty())) {
3630    PendingImplicitInstantiation Inst;
3631
3632    if (PendingLocalImplicitInstantiations.empty()) {
3633      Inst = PendingInstantiations.front();
3634      PendingInstantiations.pop_front();
3635    } else {
3636      Inst = PendingLocalImplicitInstantiations.front();
3637      PendingLocalImplicitInstantiations.pop_front();
3638    }
3639
3640    // Instantiate function definitions
3641    if (FunctionDecl *Function = dyn_cast<FunctionDecl>(Inst.first)) {
3642      PrettyDeclStackTraceEntry CrashInfo(*this, Function, SourceLocation(),
3643                                          "instantiating function definition");
3644      bool DefinitionRequired = Function->getTemplateSpecializationKind() ==
3645                                TSK_ExplicitInstantiationDefinition;
3646      InstantiateFunctionDefinition(/*FIXME:*/Inst.second, Function, true,
3647                                    DefinitionRequired);
3648      continue;
3649    }
3650
3651    // Instantiate static data member definitions.
3652    VarDecl *Var = cast<VarDecl>(Inst.first);
3653    assert(Var->isStaticDataMember() && "Not a static data member?");
3654
3655    // Don't try to instantiate declarations if the most recent redeclaration
3656    // is invalid.
3657    if (Var->getMostRecentDecl()->isInvalidDecl())
3658      continue;
3659
3660    // Check if the most recent declaration has changed the specialization kind
3661    // and removed the need for implicit instantiation.
3662    switch (Var->getMostRecentDecl()->getTemplateSpecializationKind()) {
3663    case TSK_Undeclared:
3664      llvm_unreachable("Cannot instantitiate an undeclared specialization.");
3665    case TSK_ExplicitInstantiationDeclaration:
3666    case TSK_ExplicitSpecialization:
3667      continue;  // No longer need to instantiate this type.
3668    case TSK_ExplicitInstantiationDefinition:
3669      // We only need an instantiation if the pending instantiation *is* the
3670      // explicit instantiation.
3671      if (Var != Var->getMostRecentDecl()) continue;
3672    case TSK_ImplicitInstantiation:
3673      break;
3674    }
3675
3676    PrettyDeclStackTraceEntry CrashInfo(*this, Var, Var->getLocation(),
3677                                        "instantiating static data member "
3678                                        "definition");
3679
3680    bool DefinitionRequired = Var->getTemplateSpecializationKind() ==
3681                              TSK_ExplicitInstantiationDefinition;
3682    InstantiateStaticDataMemberDefinition(/*FIXME:*/Inst.second, Var, true,
3683                                          DefinitionRequired);
3684  }
3685}
3686
3687void Sema::PerformDependentDiagnostics(const DeclContext *Pattern,
3688                       const MultiLevelTemplateArgumentList &TemplateArgs) {
3689  for (DeclContext::ddiag_iterator I = Pattern->ddiag_begin(),
3690         E = Pattern->ddiag_end(); I != E; ++I) {
3691    DependentDiagnostic *DD = *I;
3692
3693    switch (DD->getKind()) {
3694    case DependentDiagnostic::Access:
3695      HandleDependentAccessCheck(*DD, TemplateArgs);
3696      break;
3697    }
3698  }
3699}
3700