SemaTemplateInstantiateDecl.cpp revision b5b37d194dddb960f43f763b3f9c3e17e7be3c2d 
1//===--- SemaTemplateInstantiateDecl.cpp - C++ Template Decl Instantiation ===/
2//
3//                     The LLVM Compiler Infrastructure
4//
5// This file is distributed under the University of Illinois Open Source
6// License. See LICENSE.TXT for details.
7//===----------------------------------------------------------------------===/
8//
9//  This file implements C++ template instantiation for declarations.
10//
11//===----------------------------------------------------------------------===/
12#include "clang/Sema/SemaInternal.h"
13#include "clang/Sema/Lookup.h"
14#include "clang/Sema/PrettyDeclStackTrace.h"
15#include "clang/Sema/Template.h"
16#include "clang/AST/ASTConsumer.h"
17#include "clang/AST/ASTContext.h"
18#include "clang/AST/DeclTemplate.h"
19#include "clang/AST/DeclVisitor.h"
20#include "clang/AST/DependentDiagnostic.h"
21#include "clang/AST/Expr.h"
22#include "clang/AST/ExprCXX.h"
23#include "clang/AST/TypeLoc.h"
24#include "clang/Lex/Preprocessor.h"
25
26using namespace clang;
27
28bool TemplateDeclInstantiator::SubstQualifier(const DeclaratorDecl *OldDecl,
29                                              DeclaratorDecl *NewDecl) {
30  if (!OldDecl->getQualifierLoc())
31    return false;
32
33  NestedNameSpecifierLoc NewQualifierLoc
34    = SemaRef.SubstNestedNameSpecifierLoc(OldDecl->getQualifierLoc(),
35                                          TemplateArgs);
36
37  if (!NewQualifierLoc)
38    return true;
39
40  NewDecl->setQualifierInfo(NewQualifierLoc);
41  return false;
42}
43
44bool TemplateDeclInstantiator::SubstQualifier(const TagDecl *OldDecl,
45                                              TagDecl *NewDecl) {
46  if (!OldDecl->getQualifierLoc())
47    return false;
48
49  NestedNameSpecifierLoc NewQualifierLoc
50  = SemaRef.SubstNestedNameSpecifierLoc(OldDecl->getQualifierLoc(),
51                                        TemplateArgs);
52
53  if (!NewQualifierLoc)
54    return true;
55
56  NewDecl->setQualifierInfo(NewQualifierLoc);
57  return false;
58}
59
60// Include attribute instantiation code.
61#include "clang/Sema/AttrTemplateInstantiate.inc"
62
63void Sema::InstantiateAttrs(const MultiLevelTemplateArgumentList &TemplateArgs,
64                            const Decl *Tmpl, Decl *New,
65                            LateInstantiatedAttrVec *LateAttrs,
66                            LocalInstantiationScope *OuterMostScope) {
67  for (AttrVec::const_iterator i = Tmpl->attr_begin(), e = Tmpl->attr_end();
68       i != e; ++i) {
69    const Attr *TmplAttr = *i;
70
71    // FIXME: This should be generalized to more than just the AlignedAttr.
72    if (const AlignedAttr *Aligned = dyn_cast<AlignedAttr>(TmplAttr)) {
73      if (Aligned->isAlignmentDependent()) {
74        if (Aligned->isAlignmentExpr()) {
75          // The alignment expression is a constant expression.
76          EnterExpressionEvaluationContext Unevaluated(*this,
77                                                       Sema::ConstantEvaluated);
78
79          ExprResult Result = SubstExpr(Aligned->getAlignmentExpr(),
80                                        TemplateArgs);
81          if (!Result.isInvalid())
82            AddAlignedAttr(Aligned->getLocation(), New, Result.takeAs<Expr>(),
83                           Aligned->getIsMSDeclSpec());
84        } else {
85          TypeSourceInfo *Result = SubstType(Aligned->getAlignmentType(),
86                                             TemplateArgs,
87                                             Aligned->getLocation(),
88                                             DeclarationName());
89          if (Result)
90            AddAlignedAttr(Aligned->getLocation(), New, Result,
91                           Aligned->getIsMSDeclSpec());
92        }
93        continue;
94      }
95    }
96
97    if (TmplAttr->isLateParsed() && LateAttrs) {
98      // Late parsed attributes must be instantiated and attached after the
99      // enclosing class has been instantiated.  See Sema::InstantiateClass.
100      LocalInstantiationScope *Saved = 0;
101      if (CurrentInstantiationScope)
102        Saved = CurrentInstantiationScope->cloneScopes(OuterMostScope);
103      LateAttrs->push_back(LateInstantiatedAttribute(TmplAttr, Saved, New));
104    } else {
105      Attr *NewAttr = sema::instantiateTemplateAttribute(TmplAttr, Context,
106                                                         *this, TemplateArgs);
107      if (NewAttr)
108        New->addAttr(NewAttr);
109    }
110  }
111}
112
113Decl *
114TemplateDeclInstantiator::VisitTranslationUnitDecl(TranslationUnitDecl *D) {
115  llvm_unreachable("Translation units cannot be instantiated");
116}
117
118Decl *
119TemplateDeclInstantiator::VisitLabelDecl(LabelDecl *D) {
120  LabelDecl *Inst = LabelDecl::Create(SemaRef.Context, Owner, D->getLocation(),
121                                      D->getIdentifier());
122  Owner->addDecl(Inst);
123  return Inst;
124}
125
126Decl *
127TemplateDeclInstantiator::VisitNamespaceDecl(NamespaceDecl *D) {
128  llvm_unreachable("Namespaces cannot be instantiated");
129}
130
131Decl *
132TemplateDeclInstantiator::VisitNamespaceAliasDecl(NamespaceAliasDecl *D) {
133  NamespaceAliasDecl *Inst
134    = NamespaceAliasDecl::Create(SemaRef.Context, Owner,
135                                 D->getNamespaceLoc(),
136                                 D->getAliasLoc(),
137                                 D->getIdentifier(),
138                                 D->getQualifierLoc(),
139                                 D->getTargetNameLoc(),
140                                 D->getNamespace());
141  Owner->addDecl(Inst);
142  return Inst;
143}
144
145Decl *TemplateDeclInstantiator::InstantiateTypedefNameDecl(TypedefNameDecl *D,
146                                                           bool IsTypeAlias) {
147  bool Invalid = false;
148  TypeSourceInfo *DI = D->getTypeSourceInfo();
149  if (DI->getType()->isInstantiationDependentType() ||
150      DI->getType()->isVariablyModifiedType()) {
151    DI = SemaRef.SubstType(DI, TemplateArgs,
152                           D->getLocation(), D->getDeclName());
153    if (!DI) {
154      Invalid = true;
155      DI = SemaRef.Context.getTrivialTypeSourceInfo(SemaRef.Context.IntTy);
156    }
157  } else {
158    SemaRef.MarkDeclarationsReferencedInType(D->getLocation(), DI->getType());
159  }
160
161  // HACK: g++ has a bug where it gets the value kind of ?: wrong.
162  // libstdc++ relies upon this bug in its implementation of common_type.
163  // If we happen to be processing that implementation, fake up the g++ ?:
164  // semantics. See LWG issue 2141 for more information on the bug.
165  const DecltypeType *DT = DI->getType()->getAs<DecltypeType>();
166  CXXRecordDecl *RD = dyn_cast<CXXRecordDecl>(D->getDeclContext());
167  if (DT && RD && isa<ConditionalOperator>(DT->getUnderlyingExpr()) &&
168      DT->isReferenceType() &&
169      RD->getEnclosingNamespaceContext() == SemaRef.getStdNamespace() &&
170      RD->getIdentifier() && RD->getIdentifier()->isStr("common_type") &&
171      D->getIdentifier() && D->getIdentifier()->isStr("type") &&
172      SemaRef.getSourceManager().isInSystemHeader(D->getLocStart()))
173    // Fold it to the (non-reference) type which g++ would have produced.
174    DI = SemaRef.Context.getTrivialTypeSourceInfo(
175      DI->getType().getNonReferenceType());
176
177  // Create the new typedef
178  TypedefNameDecl *Typedef;
179  if (IsTypeAlias)
180    Typedef = TypeAliasDecl::Create(SemaRef.Context, Owner, D->getLocStart(),
181                                    D->getLocation(), D->getIdentifier(), DI);
182  else
183    Typedef = TypedefDecl::Create(SemaRef.Context, Owner, D->getLocStart(),
184                                  D->getLocation(), D->getIdentifier(), DI);
185  if (Invalid)
186    Typedef->setInvalidDecl();
187
188  // If the old typedef was the name for linkage purposes of an anonymous
189  // tag decl, re-establish that relationship for the new typedef.
190  if (const TagType *oldTagType = D->getUnderlyingType()->getAs<TagType>()) {
191    TagDecl *oldTag = oldTagType->getDecl();
192    if (oldTag->getTypedefNameForAnonDecl() == D) {
193      TagDecl *newTag = DI->getType()->castAs<TagType>()->getDecl();
194      assert(!newTag->getIdentifier() && !newTag->getTypedefNameForAnonDecl());
195      newTag->setTypedefNameForAnonDecl(Typedef);
196    }
197  }
198
199  if (TypedefNameDecl *Prev = D->getPreviousDecl()) {
200    NamedDecl *InstPrev = SemaRef.FindInstantiatedDecl(D->getLocation(), Prev,
201                                                       TemplateArgs);
202    if (!InstPrev)
203      return 0;
204
205    TypedefNameDecl *InstPrevTypedef = cast<TypedefNameDecl>(InstPrev);
206
207    // If the typedef types are not identical, reject them.
208    SemaRef.isIncompatibleTypedef(InstPrevTypedef, Typedef);
209
210    Typedef->setPreviousDeclaration(InstPrevTypedef);
211  }
212
213  SemaRef.InstantiateAttrs(TemplateArgs, D, Typedef);
214
215  Typedef->setAccess(D->getAccess());
216
217  return Typedef;
218}
219
220Decl *TemplateDeclInstantiator::VisitTypedefDecl(TypedefDecl *D) {
221  Decl *Typedef = InstantiateTypedefNameDecl(D, /*IsTypeAlias=*/false);
222  Owner->addDecl(Typedef);
223  return Typedef;
224}
225
226Decl *TemplateDeclInstantiator::VisitTypeAliasDecl(TypeAliasDecl *D) {
227  Decl *Typedef = InstantiateTypedefNameDecl(D, /*IsTypeAlias=*/true);
228  Owner->addDecl(Typedef);
229  return Typedef;
230}
231
232Decl *
233TemplateDeclInstantiator::VisitTypeAliasTemplateDecl(TypeAliasTemplateDecl *D) {
234  // Create a local instantiation scope for this type alias template, which
235  // will contain the instantiations of the template parameters.
236  LocalInstantiationScope Scope(SemaRef);
237
238  TemplateParameterList *TempParams = D->getTemplateParameters();
239  TemplateParameterList *InstParams = SubstTemplateParams(TempParams);
240  if (!InstParams)
241    return 0;
242
243  TypeAliasDecl *Pattern = D->getTemplatedDecl();
244
245  TypeAliasTemplateDecl *PrevAliasTemplate = 0;
246  if (Pattern->getPreviousDecl()) {
247    DeclContext::lookup_result Found = Owner->lookup(Pattern->getDeclName());
248    if (Found.first != Found.second) {
249      PrevAliasTemplate = dyn_cast<TypeAliasTemplateDecl>(*Found.first);
250    }
251  }
252
253  TypeAliasDecl *AliasInst = cast_or_null<TypeAliasDecl>(
254    InstantiateTypedefNameDecl(Pattern, /*IsTypeAlias=*/true));
255  if (!AliasInst)
256    return 0;
257
258  TypeAliasTemplateDecl *Inst
259    = TypeAliasTemplateDecl::Create(SemaRef.Context, Owner, D->getLocation(),
260                                    D->getDeclName(), InstParams, AliasInst);
261  if (PrevAliasTemplate)
262    Inst->setPreviousDeclaration(PrevAliasTemplate);
263
264  Inst->setAccess(D->getAccess());
265
266  if (!PrevAliasTemplate)
267    Inst->setInstantiatedFromMemberTemplate(D);
268
269  Owner->addDecl(Inst);
270
271  return Inst;
272}
273
274Decl *TemplateDeclInstantiator::VisitVarDecl(VarDecl *D) {
275  // If this is the variable for an anonymous struct or union,
276  // instantiate the anonymous struct/union type first.
277  if (const RecordType *RecordTy = D->getType()->getAs<RecordType>())
278    if (RecordTy->getDecl()->isAnonymousStructOrUnion())
279      if (!VisitCXXRecordDecl(cast<CXXRecordDecl>(RecordTy->getDecl())))
280        return 0;
281
282  // Do substitution on the type of the declaration
283  TypeSourceInfo *DI = SemaRef.SubstType(D->getTypeSourceInfo(),
284                                         TemplateArgs,
285                                         D->getTypeSpecStartLoc(),
286                                         D->getDeclName());
287  if (!DI)
288    return 0;
289
290  if (DI->getType()->isFunctionType()) {
291    SemaRef.Diag(D->getLocation(), diag::err_variable_instantiates_to_function)
292      << D->isStaticDataMember() << DI->getType();
293    return 0;
294  }
295
296  // Build the instantiated declaration
297  VarDecl *Var = VarDecl::Create(SemaRef.Context, Owner,
298                                 D->getInnerLocStart(),
299                                 D->getLocation(), D->getIdentifier(),
300                                 DI->getType(), DI,
301                                 D->getStorageClass(),
302                                 D->getStorageClassAsWritten());
303  Var->setThreadSpecified(D->isThreadSpecified());
304  Var->setInitStyle(D->getInitStyle());
305  Var->setCXXForRangeDecl(D->isCXXForRangeDecl());
306  Var->setConstexpr(D->isConstexpr());
307
308  // Substitute the nested name specifier, if any.
309  if (SubstQualifier(D, Var))
310    return 0;
311
312  // If we are instantiating a static data member defined
313  // out-of-line, the instantiation will have the same lexical
314  // context (which will be a namespace scope) as the template.
315  if (D->isOutOfLine())
316    Var->setLexicalDeclContext(D->getLexicalDeclContext());
317
318  Var->setAccess(D->getAccess());
319
320  if (!D->isStaticDataMember()) {
321    Var->setUsed(D->isUsed(false));
322    Var->setReferenced(D->isReferenced());
323  }
324
325  // FIXME: In theory, we could have a previous declaration for variables that
326  // are not static data members.
327  // FIXME: having to fake up a LookupResult is dumb.
328  LookupResult Previous(SemaRef, Var->getDeclName(), Var->getLocation(),
329                        Sema::LookupOrdinaryName, Sema::ForRedeclaration);
330  if (D->isStaticDataMember())
331    SemaRef.LookupQualifiedName(Previous, Owner, false);
332
333  // In ARC, infer 'retaining' for variables of retainable type.
334  if (SemaRef.getLangOpts().ObjCAutoRefCount &&
335      SemaRef.inferObjCARCLifetime(Var))
336    Var->setInvalidDecl();
337
338  SemaRef.CheckVariableDeclaration(Var, Previous);
339
340  if (D->isOutOfLine()) {
341    D->getLexicalDeclContext()->addDecl(Var);
342    Owner->makeDeclVisibleInContext(Var);
343  } else {
344    Owner->addDecl(Var);
345    if (Owner->isFunctionOrMethod())
346      SemaRef.CurrentInstantiationScope->InstantiatedLocal(D, Var);
347  }
348  SemaRef.InstantiateAttrs(TemplateArgs, D, Var, LateAttrs, StartingScope);
349
350  // Link instantiations of static data members back to the template from
351  // which they were instantiated.
352  if (Var->isStaticDataMember())
353    SemaRef.Context.setInstantiatedFromStaticDataMember(Var, D,
354                                                     TSK_ImplicitInstantiation);
355
356  if (Var->getAnyInitializer()) {
357    // We already have an initializer in the class.
358  } else if (D->getInit()) {
359    if (Var->isStaticDataMember() && !D->isOutOfLine())
360      SemaRef.PushExpressionEvaluationContext(Sema::ConstantEvaluated, D);
361    else
362      SemaRef.PushExpressionEvaluationContext(Sema::PotentiallyEvaluated, D);
363
364    // Instantiate the initializer.
365    ExprResult Init = SemaRef.SubstInitializer(D->getInit(), TemplateArgs,
366                                        D->getInitStyle() == VarDecl::CallInit);
367    if (!Init.isInvalid()) {
368      bool TypeMayContainAuto = true;
369      if (Init.get()) {
370        bool DirectInit = D->isDirectInit();
371        SemaRef.AddInitializerToDecl(Var, Init.take(), DirectInit,
372                                     TypeMayContainAuto);
373      } else
374        SemaRef.ActOnUninitializedDecl(Var, TypeMayContainAuto);
375    } else {
376      // FIXME: Not too happy about invalidating the declaration
377      // because of a bogus initializer.
378      Var->setInvalidDecl();
379    }
380
381    SemaRef.PopExpressionEvaluationContext();
382  } else if ((!Var->isStaticDataMember() || Var->isOutOfLine()) &&
383             !Var->isCXXForRangeDecl())
384    SemaRef.ActOnUninitializedDecl(Var, false);
385
386  // Diagnose unused local variables with dependent types, where the diagnostic
387  // will have been deferred.
388  if (!Var->isInvalidDecl() && Owner->isFunctionOrMethod() && !Var->isUsed() &&
389      D->getType()->isDependentType())
390    SemaRef.DiagnoseUnusedDecl(Var);
391
392  return Var;
393}
394
395Decl *TemplateDeclInstantiator::VisitAccessSpecDecl(AccessSpecDecl *D) {
396  AccessSpecDecl* AD
397    = AccessSpecDecl::Create(SemaRef.Context, D->getAccess(), Owner,
398                             D->getAccessSpecifierLoc(), D->getColonLoc());
399  Owner->addHiddenDecl(AD);
400  return AD;
401}
402
403Decl *TemplateDeclInstantiator::VisitFieldDecl(FieldDecl *D) {
404  bool Invalid = false;
405  TypeSourceInfo *DI = D->getTypeSourceInfo();
406  if (DI->getType()->isInstantiationDependentType() ||
407      DI->getType()->isVariablyModifiedType())  {
408    DI = SemaRef.SubstType(DI, TemplateArgs,
409                           D->getLocation(), D->getDeclName());
410    if (!DI) {
411      DI = D->getTypeSourceInfo();
412      Invalid = true;
413    } else if (DI->getType()->isFunctionType()) {
414      // C++ [temp.arg.type]p3:
415      //   If a declaration acquires a function type through a type
416      //   dependent on a template-parameter and this causes a
417      //   declaration that does not use the syntactic form of a
418      //   function declarator to have function type, the program is
419      //   ill-formed.
420      SemaRef.Diag(D->getLocation(), diag::err_field_instantiates_to_function)
421        << DI->getType();
422      Invalid = true;
423    }
424  } else {
425    SemaRef.MarkDeclarationsReferencedInType(D->getLocation(), DI->getType());
426  }
427
428  Expr *BitWidth = D->getBitWidth();
429  if (Invalid)
430    BitWidth = 0;
431  else if (BitWidth) {
432    // The bit-width expression is a constant expression.
433    EnterExpressionEvaluationContext Unevaluated(SemaRef,
434                                                 Sema::ConstantEvaluated);
435
436    ExprResult InstantiatedBitWidth
437      = SemaRef.SubstExpr(BitWidth, TemplateArgs);
438    if (InstantiatedBitWidth.isInvalid()) {
439      Invalid = true;
440      BitWidth = 0;
441    } else
442      BitWidth = InstantiatedBitWidth.takeAs<Expr>();
443  }
444
445  FieldDecl *Field = SemaRef.CheckFieldDecl(D->getDeclName(),
446                                            DI->getType(), DI,
447                                            cast<RecordDecl>(Owner),
448                                            D->getLocation(),
449                                            D->isMutable(),
450                                            BitWidth,
451                                            D->getInClassInitStyle(),
452                                            D->getInnerLocStart(),
453                                            D->getAccess(),
454                                            0);
455  if (!Field) {
456    cast<Decl>(Owner)->setInvalidDecl();
457    return 0;
458  }
459
460  SemaRef.InstantiateAttrs(TemplateArgs, D, Field, LateAttrs, StartingScope);
461
462  if (Invalid)
463    Field->setInvalidDecl();
464
465  if (!Field->getDeclName()) {
466    // Keep track of where this decl came from.
467    SemaRef.Context.setInstantiatedFromUnnamedFieldDecl(Field, D);
468  }
469  if (CXXRecordDecl *Parent= dyn_cast<CXXRecordDecl>(Field->getDeclContext())) {
470    if (Parent->isAnonymousStructOrUnion() &&
471        Parent->getRedeclContext()->isFunctionOrMethod())
472      SemaRef.CurrentInstantiationScope->InstantiatedLocal(D, Field);
473  }
474
475  Field->setImplicit(D->isImplicit());
476  Field->setAccess(D->getAccess());
477  Owner->addDecl(Field);
478
479  return Field;
480}
481
482Decl *TemplateDeclInstantiator::VisitIndirectFieldDecl(IndirectFieldDecl *D) {
483  NamedDecl **NamedChain =
484    new (SemaRef.Context)NamedDecl*[D->getChainingSize()];
485
486  int i = 0;
487  for (IndirectFieldDecl::chain_iterator PI =
488       D->chain_begin(), PE = D->chain_end();
489       PI != PE; ++PI) {
490    NamedDecl *Next = SemaRef.FindInstantiatedDecl(D->getLocation(), *PI,
491                                              TemplateArgs);
492    if (!Next)
493      return 0;
494
495    NamedChain[i++] = Next;
496  }
497
498  QualType T = cast<FieldDecl>(NamedChain[i-1])->getType();
499  IndirectFieldDecl* IndirectField
500    = IndirectFieldDecl::Create(SemaRef.Context, Owner, D->getLocation(),
501                                D->getIdentifier(), T,
502                                NamedChain, D->getChainingSize());
503
504
505  IndirectField->setImplicit(D->isImplicit());
506  IndirectField->setAccess(D->getAccess());
507  Owner->addDecl(IndirectField);
508  return IndirectField;
509}
510
511Decl *TemplateDeclInstantiator::VisitFriendDecl(FriendDecl *D) {
512  // Handle friend type expressions by simply substituting template
513  // parameters into the pattern type and checking the result.
514  if (TypeSourceInfo *Ty = D->getFriendType()) {
515    TypeSourceInfo *InstTy;
516    // If this is an unsupported friend, don't bother substituting template
517    // arguments into it. The actual type referred to won't be used by any
518    // parts of Clang, and may not be valid for instantiating. Just use the
519    // same info for the instantiated friend.
520    if (D->isUnsupportedFriend()) {
521      InstTy = Ty;
522    } else {
523      InstTy = SemaRef.SubstType(Ty, TemplateArgs,
524                                 D->getLocation(), DeclarationName());
525    }
526    if (!InstTy)
527      return 0;
528
529    FriendDecl *FD = SemaRef.CheckFriendTypeDecl(D->getLocStart(),
530                                                 D->getFriendLoc(), InstTy);
531    if (!FD)
532      return 0;
533
534    FD->setAccess(AS_public);
535    FD->setUnsupportedFriend(D->isUnsupportedFriend());
536    Owner->addDecl(FD);
537    return FD;
538  }
539
540  NamedDecl *ND = D->getFriendDecl();
541  assert(ND && "friend decl must be a decl or a type!");
542
543  // All of the Visit implementations for the various potential friend
544  // declarations have to be carefully written to work for friend
545  // objects, with the most important detail being that the target
546  // decl should almost certainly not be placed in Owner.
547  Decl *NewND = Visit(ND);
548  if (!NewND) return 0;
549
550  FriendDecl *FD =
551    FriendDecl::Create(SemaRef.Context, Owner, D->getLocation(),
552                       cast<NamedDecl>(NewND), D->getFriendLoc());
553  FD->setAccess(AS_public);
554  FD->setUnsupportedFriend(D->isUnsupportedFriend());
555  Owner->addDecl(FD);
556  return FD;
557}
558
559Decl *TemplateDeclInstantiator::VisitStaticAssertDecl(StaticAssertDecl *D) {
560  Expr *AssertExpr = D->getAssertExpr();
561
562  // The expression in a static assertion is a constant expression.
563  EnterExpressionEvaluationContext Unevaluated(SemaRef,
564                                               Sema::ConstantEvaluated);
565
566  ExprResult InstantiatedAssertExpr
567    = SemaRef.SubstExpr(AssertExpr, TemplateArgs);
568  if (InstantiatedAssertExpr.isInvalid())
569    return 0;
570
571  return SemaRef.BuildStaticAssertDeclaration(D->getLocation(),
572                                              InstantiatedAssertExpr.get(),
573                                              D->getMessage(),
574                                              D->getRParenLoc(),
575                                              D->isFailed());
576}
577
578Decl *TemplateDeclInstantiator::VisitEnumDecl(EnumDecl *D) {
579  EnumDecl *PrevDecl = 0;
580  if (D->getPreviousDecl()) {
581    NamedDecl *Prev = SemaRef.FindInstantiatedDecl(D->getLocation(),
582                                                   D->getPreviousDecl(),
583                                                   TemplateArgs);
584    if (!Prev) return 0;
585    PrevDecl = cast<EnumDecl>(Prev);
586  }
587
588  EnumDecl *Enum = EnumDecl::Create(SemaRef.Context, Owner, D->getLocStart(),
589                                    D->getLocation(), D->getIdentifier(),
590                                    PrevDecl, D->isScoped(),
591                                    D->isScopedUsingClassTag(), D->isFixed());
592  if (D->isFixed()) {
593    if (TypeSourceInfo *TI = D->getIntegerTypeSourceInfo()) {
594      // If we have type source information for the underlying type, it means it
595      // has been explicitly set by the user. Perform substitution on it before
596      // moving on.
597      SourceLocation UnderlyingLoc = TI->getTypeLoc().getBeginLoc();
598      TypeSourceInfo *NewTI = SemaRef.SubstType(TI, TemplateArgs, UnderlyingLoc,
599                                                DeclarationName());
600      if (!NewTI || SemaRef.CheckEnumUnderlyingType(NewTI))
601        Enum->setIntegerType(SemaRef.Context.IntTy);
602      else
603        Enum->setIntegerTypeSourceInfo(NewTI);
604    } else {
605      assert(!D->getIntegerType()->isDependentType()
606             && "Dependent type without type source info");
607      Enum->setIntegerType(D->getIntegerType());
608    }
609  }
610
611  SemaRef.InstantiateAttrs(TemplateArgs, D, Enum);
612
613  Enum->setInstantiationOfMemberEnum(D, TSK_ImplicitInstantiation);
614  Enum->setAccess(D->getAccess());
615  if (SubstQualifier(D, Enum)) return 0;
616  Owner->addDecl(Enum);
617
618  EnumDecl *Def = D->getDefinition();
619  if (Def && Def != D) {
620    // If this is an out-of-line definition of an enum member template, check
621    // that the underlying types match in the instantiation of both
622    // declarations.
623    if (TypeSourceInfo *TI = Def->getIntegerTypeSourceInfo()) {
624      SourceLocation UnderlyingLoc = TI->getTypeLoc().getBeginLoc();
625      QualType DefnUnderlying =
626        SemaRef.SubstType(TI->getType(), TemplateArgs,
627                          UnderlyingLoc, DeclarationName());
628      SemaRef.CheckEnumRedeclaration(Def->getLocation(), Def->isScoped(),
629                                     DefnUnderlying, Enum);
630    }
631  }
632
633  if (D->getDeclContext()->isFunctionOrMethod())
634    SemaRef.CurrentInstantiationScope->InstantiatedLocal(D, Enum);
635
636  // C++11 [temp.inst]p1: The implicit instantiation of a class template
637  // specialization causes the implicit instantiation of the declarations, but
638  // not the definitions of scoped member enumerations.
639  // FIXME: There appears to be no wording for what happens for an enum defined
640  // within a block scope, but we treat that much like a member template. Only
641  // instantiate the definition when visiting the definition in that case, since
642  // we will visit all redeclarations.
643  if (!Enum->isScoped() && Def &&
644      (!D->getDeclContext()->isFunctionOrMethod() || D->isCompleteDefinition()))
645    InstantiateEnumDefinition(Enum, Def);
646
647  return Enum;
648}
649
650void TemplateDeclInstantiator::InstantiateEnumDefinition(
651    EnumDecl *Enum, EnumDecl *Pattern) {
652  Enum->startDefinition();
653
654  // Update the location to refer to the definition.
655  Enum->setLocation(Pattern->getLocation());
656
657  SmallVector<Decl*, 4> Enumerators;
658
659  EnumConstantDecl *LastEnumConst = 0;
660  for (EnumDecl::enumerator_iterator EC = Pattern->enumerator_begin(),
661         ECEnd = Pattern->enumerator_end();
662       EC != ECEnd; ++EC) {
663    // The specified value for the enumerator.
664    ExprResult Value = SemaRef.Owned((Expr *)0);
665    if (Expr *UninstValue = EC->getInitExpr()) {
666      // The enumerator's value expression is a constant expression.
667      EnterExpressionEvaluationContext Unevaluated(SemaRef,
668                                                   Sema::ConstantEvaluated);
669
670      Value = SemaRef.SubstExpr(UninstValue, TemplateArgs);
671    }
672
673    // Drop the initial value and continue.
674    bool isInvalid = false;
675    if (Value.isInvalid()) {
676      Value = SemaRef.Owned((Expr *)0);
677      isInvalid = true;
678    }
679
680    EnumConstantDecl *EnumConst
681      = SemaRef.CheckEnumConstant(Enum, LastEnumConst,
682                                  EC->getLocation(), EC->getIdentifier(),
683                                  Value.get());
684
685    if (isInvalid) {
686      if (EnumConst)
687        EnumConst->setInvalidDecl();
688      Enum->setInvalidDecl();
689    }
690
691    if (EnumConst) {
692      SemaRef.InstantiateAttrs(TemplateArgs, *EC, EnumConst);
693
694      EnumConst->setAccess(Enum->getAccess());
695      Enum->addDecl(EnumConst);
696      Enumerators.push_back(EnumConst);
697      LastEnumConst = EnumConst;
698
699      if (Pattern->getDeclContext()->isFunctionOrMethod() &&
700          !Enum->isScoped()) {
701        // If the enumeration is within a function or method, record the enum
702        // constant as a local.
703        SemaRef.CurrentInstantiationScope->InstantiatedLocal(*EC, EnumConst);
704      }
705    }
706  }
707
708  // FIXME: Fixup LBraceLoc
709  SemaRef.ActOnEnumBody(Enum->getLocation(), SourceLocation(),
710                        Enum->getRBraceLoc(), Enum,
711                        Enumerators.data(), Enumerators.size(),
712                        0, 0);
713}
714
715Decl *TemplateDeclInstantiator::VisitEnumConstantDecl(EnumConstantDecl *D) {
716  llvm_unreachable("EnumConstantDecls can only occur within EnumDecls.");
717}
718
719Decl *TemplateDeclInstantiator::VisitClassTemplateDecl(ClassTemplateDecl *D) {
720  bool isFriend = (D->getFriendObjectKind() != Decl::FOK_None);
721
722  // Create a local instantiation scope for this class template, which
723  // will contain the instantiations of the template parameters.
724  LocalInstantiationScope Scope(SemaRef);
725  TemplateParameterList *TempParams = D->getTemplateParameters();
726  TemplateParameterList *InstParams = SubstTemplateParams(TempParams);
727  if (!InstParams)
728    return NULL;
729
730  CXXRecordDecl *Pattern = D->getTemplatedDecl();
731
732  // Instantiate the qualifier.  We have to do this first in case
733  // we're a friend declaration, because if we are then we need to put
734  // the new declaration in the appropriate context.
735  NestedNameSpecifierLoc QualifierLoc = Pattern->getQualifierLoc();
736  if (QualifierLoc) {
737    QualifierLoc = SemaRef.SubstNestedNameSpecifierLoc(QualifierLoc,
738                                                       TemplateArgs);
739    if (!QualifierLoc)
740      return 0;
741  }
742
743  CXXRecordDecl *PrevDecl = 0;
744  ClassTemplateDecl *PrevClassTemplate = 0;
745
746  if (!isFriend && Pattern->getPreviousDecl()) {
747    DeclContext::lookup_result Found = Owner->lookup(Pattern->getDeclName());
748    if (Found.first != Found.second) {
749      PrevClassTemplate = dyn_cast<ClassTemplateDecl>(*Found.first);
750      if (PrevClassTemplate)
751        PrevDecl = PrevClassTemplate->getTemplatedDecl();
752    }
753  }
754
755  // If this isn't a friend, then it's a member template, in which
756  // case we just want to build the instantiation in the
757  // specialization.  If it is a friend, we want to build it in
758  // the appropriate context.
759  DeclContext *DC = Owner;
760  if (isFriend) {
761    if (QualifierLoc) {
762      CXXScopeSpec SS;
763      SS.Adopt(QualifierLoc);
764      DC = SemaRef.computeDeclContext(SS);
765      if (!DC) return 0;
766    } else {
767      DC = SemaRef.FindInstantiatedContext(Pattern->getLocation(),
768                                           Pattern->getDeclContext(),
769                                           TemplateArgs);
770    }
771
772    // Look for a previous declaration of the template in the owning
773    // context.
774    LookupResult R(SemaRef, Pattern->getDeclName(), Pattern->getLocation(),
775                   Sema::LookupOrdinaryName, Sema::ForRedeclaration);
776    SemaRef.LookupQualifiedName(R, DC);
777
778    if (R.isSingleResult()) {
779      PrevClassTemplate = R.getAsSingle<ClassTemplateDecl>();
780      if (PrevClassTemplate)
781        PrevDecl = PrevClassTemplate->getTemplatedDecl();
782    }
783
784    if (!PrevClassTemplate && QualifierLoc) {
785      SemaRef.Diag(Pattern->getLocation(), diag::err_not_tag_in_scope)
786        << D->getTemplatedDecl()->getTagKind() << Pattern->getDeclName() << DC
787        << QualifierLoc.getSourceRange();
788      return 0;
789    }
790
791    bool AdoptedPreviousTemplateParams = false;
792    if (PrevClassTemplate) {
793      bool Complain = true;
794
795      // HACK: libstdc++ 4.2.1 contains an ill-formed friend class
796      // template for struct std::tr1::__detail::_Map_base, where the
797      // template parameters of the friend declaration don't match the
798      // template parameters of the original declaration. In this one
799      // case, we don't complain about the ill-formed friend
800      // declaration.
801      if (isFriend && Pattern->getIdentifier() &&
802          Pattern->getIdentifier()->isStr("_Map_base") &&
803          DC->isNamespace() &&
804          cast<NamespaceDecl>(DC)->getIdentifier() &&
805          cast<NamespaceDecl>(DC)->getIdentifier()->isStr("__detail")) {
806        DeclContext *DCParent = DC->getParent();
807        if (DCParent->isNamespace() &&
808            cast<NamespaceDecl>(DCParent)->getIdentifier() &&
809            cast<NamespaceDecl>(DCParent)->getIdentifier()->isStr("tr1")) {
810          DeclContext *DCParent2 = DCParent->getParent();
811          if (DCParent2->isNamespace() &&
812              cast<NamespaceDecl>(DCParent2)->getIdentifier() &&
813              cast<NamespaceDecl>(DCParent2)->getIdentifier()->isStr("std") &&
814              DCParent2->getParent()->isTranslationUnit())
815            Complain = false;
816        }
817      }
818
819      TemplateParameterList *PrevParams
820        = PrevClassTemplate->getTemplateParameters();
821
822      // Make sure the parameter lists match.
823      if (!SemaRef.TemplateParameterListsAreEqual(InstParams, PrevParams,
824                                                  Complain,
825                                                  Sema::TPL_TemplateMatch)) {
826        if (Complain)
827          return 0;
828
829        AdoptedPreviousTemplateParams = true;
830        InstParams = PrevParams;
831      }
832
833      // Do some additional validation, then merge default arguments
834      // from the existing declarations.
835      if (!AdoptedPreviousTemplateParams &&
836          SemaRef.CheckTemplateParameterList(InstParams, PrevParams,
837                                             Sema::TPC_ClassTemplate))
838        return 0;
839    }
840  }
841
842  CXXRecordDecl *RecordInst
843    = CXXRecordDecl::Create(SemaRef.Context, Pattern->getTagKind(), DC,
844                            Pattern->getLocStart(), Pattern->getLocation(),
845                            Pattern->getIdentifier(), PrevDecl,
846                            /*DelayTypeCreation=*/true);
847
848  if (QualifierLoc)
849    RecordInst->setQualifierInfo(QualifierLoc);
850
851  ClassTemplateDecl *Inst
852    = ClassTemplateDecl::Create(SemaRef.Context, DC, D->getLocation(),
853                                D->getIdentifier(), InstParams, RecordInst,
854                                PrevClassTemplate);
855  RecordInst->setDescribedClassTemplate(Inst);
856
857  if (isFriend) {
858    if (PrevClassTemplate)
859      Inst->setAccess(PrevClassTemplate->getAccess());
860    else
861      Inst->setAccess(D->getAccess());
862
863    Inst->setObjectOfFriendDecl(PrevClassTemplate != 0);
864    // TODO: do we want to track the instantiation progeny of this
865    // friend target decl?
866  } else {
867    Inst->setAccess(D->getAccess());
868    if (!PrevClassTemplate)
869      Inst->setInstantiatedFromMemberTemplate(D);
870  }
871
872  // Trigger creation of the type for the instantiation.
873  SemaRef.Context.getInjectedClassNameType(RecordInst,
874                                    Inst->getInjectedClassNameSpecialization());
875
876  // Finish handling of friends.
877  if (isFriend) {
878    DC->makeDeclVisibleInContext(Inst);
879    Inst->setLexicalDeclContext(Owner);
880    RecordInst->setLexicalDeclContext(Owner);
881    return Inst;
882  }
883
884  if (D->isOutOfLine()) {
885    Inst->setLexicalDeclContext(D->getLexicalDeclContext());
886    RecordInst->setLexicalDeclContext(D->getLexicalDeclContext());
887  }
888
889  Owner->addDecl(Inst);
890
891  if (!PrevClassTemplate) {
892    // Queue up any out-of-line partial specializations of this member
893    // class template; the client will force their instantiation once
894    // the enclosing class has been instantiated.
895    SmallVector<ClassTemplatePartialSpecializationDecl *, 4> PartialSpecs;
896    D->getPartialSpecializations(PartialSpecs);
897    for (unsigned I = 0, N = PartialSpecs.size(); I != N; ++I)
898      if (PartialSpecs[I]->isOutOfLine())
899        OutOfLinePartialSpecs.push_back(std::make_pair(Inst, PartialSpecs[I]));
900  }
901
902  return Inst;
903}
904
905Decl *
906TemplateDeclInstantiator::VisitClassTemplatePartialSpecializationDecl(
907                                   ClassTemplatePartialSpecializationDecl *D) {
908  ClassTemplateDecl *ClassTemplate = D->getSpecializedTemplate();
909
910  // Lookup the already-instantiated declaration in the instantiation
911  // of the class template and return that.
912  DeclContext::lookup_result Found
913    = Owner->lookup(ClassTemplate->getDeclName());
914  if (Found.first == Found.second)
915    return 0;
916
917  ClassTemplateDecl *InstClassTemplate
918    = dyn_cast<ClassTemplateDecl>(*Found.first);
919  if (!InstClassTemplate)
920    return 0;
921
922  if (ClassTemplatePartialSpecializationDecl *Result
923        = InstClassTemplate->findPartialSpecInstantiatedFromMember(D))
924    return Result;
925
926  return InstantiateClassTemplatePartialSpecialization(InstClassTemplate, D);
927}
928
929Decl *
930TemplateDeclInstantiator::VisitFunctionTemplateDecl(FunctionTemplateDecl *D) {
931  // Create a local instantiation scope for this function template, which
932  // will contain the instantiations of the template parameters and then get
933  // merged with the local instantiation scope for the function template
934  // itself.
935  LocalInstantiationScope Scope(SemaRef);
936
937  TemplateParameterList *TempParams = D->getTemplateParameters();
938  TemplateParameterList *InstParams = SubstTemplateParams(TempParams);
939  if (!InstParams)
940    return NULL;
941
942  FunctionDecl *Instantiated = 0;
943  if (CXXMethodDecl *DMethod = dyn_cast<CXXMethodDecl>(D->getTemplatedDecl()))
944    Instantiated = cast_or_null<FunctionDecl>(VisitCXXMethodDecl(DMethod,
945                                                                 InstParams));
946  else
947    Instantiated = cast_or_null<FunctionDecl>(VisitFunctionDecl(
948                                                          D->getTemplatedDecl(),
949                                                                InstParams));
950
951  if (!Instantiated)
952    return 0;
953
954  // Link the instantiated function template declaration to the function
955  // template from which it was instantiated.
956  FunctionTemplateDecl *InstTemplate
957    = Instantiated->getDescribedFunctionTemplate();
958  InstTemplate->setAccess(D->getAccess());
959  assert(InstTemplate &&
960         "VisitFunctionDecl/CXXMethodDecl didn't create a template!");
961
962  bool isFriend = (InstTemplate->getFriendObjectKind() != Decl::FOK_None);
963
964  // Link the instantiation back to the pattern *unless* this is a
965  // non-definition friend declaration.
966  if (!InstTemplate->getInstantiatedFromMemberTemplate() &&
967      !(isFriend && !D->getTemplatedDecl()->isThisDeclarationADefinition()))
968    InstTemplate->setInstantiatedFromMemberTemplate(D);
969
970  // Make declarations visible in the appropriate context.
971  if (!isFriend) {
972    Owner->addDecl(InstTemplate);
973  } else if (InstTemplate->getDeclContext()->isRecord() &&
974             !D->getPreviousDecl()) {
975    SemaRef.CheckFriendAccess(InstTemplate);
976  }
977
978  return InstTemplate;
979}
980
981Decl *TemplateDeclInstantiator::VisitCXXRecordDecl(CXXRecordDecl *D) {
982  CXXRecordDecl *PrevDecl = 0;
983  if (D->isInjectedClassName())
984    PrevDecl = cast<CXXRecordDecl>(Owner);
985  else if (D->getPreviousDecl()) {
986    NamedDecl *Prev = SemaRef.FindInstantiatedDecl(D->getLocation(),
987                                                   D->getPreviousDecl(),
988                                                   TemplateArgs);
989    if (!Prev) return 0;
990    PrevDecl = cast<CXXRecordDecl>(Prev);
991  }
992
993  CXXRecordDecl *Record
994    = CXXRecordDecl::Create(SemaRef.Context, D->getTagKind(), Owner,
995                            D->getLocStart(), D->getLocation(),
996                            D->getIdentifier(), PrevDecl);
997
998  // Substitute the nested name specifier, if any.
999  if (SubstQualifier(D, Record))
1000    return 0;
1001
1002  Record->setImplicit(D->isImplicit());
1003  // FIXME: Check against AS_none is an ugly hack to work around the issue that
1004  // the tag decls introduced by friend class declarations don't have an access
1005  // specifier. Remove once this area of the code gets sorted out.
1006  if (D->getAccess() != AS_none)
1007    Record->setAccess(D->getAccess());
1008  if (!D->isInjectedClassName())
1009    Record->setInstantiationOfMemberClass(D, TSK_ImplicitInstantiation);
1010
1011  // If the original function was part of a friend declaration,
1012  // inherit its namespace state.
1013  if (Decl::FriendObjectKind FOK = D->getFriendObjectKind())
1014    Record->setObjectOfFriendDecl(FOK == Decl::FOK_Declared);
1015
1016  // Make sure that anonymous structs and unions are recorded.
1017  if (D->isAnonymousStructOrUnion()) {
1018    Record->setAnonymousStructOrUnion(true);
1019    if (Record->getDeclContext()->getRedeclContext()->isFunctionOrMethod())
1020      SemaRef.CurrentInstantiationScope->InstantiatedLocal(D, Record);
1021  }
1022
1023  Owner->addDecl(Record);
1024  return Record;
1025}
1026
1027/// \brief Adjust the given function type for an instantiation of the
1028/// given declaration, to cope with modifications to the function's type that
1029/// aren't reflected in the type-source information.
1030///
1031/// \param D The declaration we're instantiating.
1032/// \param TInfo The already-instantiated type.
1033static QualType adjustFunctionTypeForInstantiation(ASTContext &Context,
1034                                                   FunctionDecl *D,
1035                                                   TypeSourceInfo *TInfo) {
1036  const FunctionProtoType *OrigFunc
1037    = D->getType()->castAs<FunctionProtoType>();
1038  const FunctionProtoType *NewFunc
1039    = TInfo->getType()->castAs<FunctionProtoType>();
1040  if (OrigFunc->getExtInfo() == NewFunc->getExtInfo())
1041    return TInfo->getType();
1042
1043  FunctionProtoType::ExtProtoInfo NewEPI = NewFunc->getExtProtoInfo();
1044  NewEPI.ExtInfo = OrigFunc->getExtInfo();
1045  return Context.getFunctionType(NewFunc->getResultType(),
1046                                 NewFunc->arg_type_begin(),
1047                                 NewFunc->getNumArgs(),
1048                                 NewEPI);
1049}
1050
1051/// Normal class members are of more specific types and therefore
1052/// don't make it here.  This function serves two purposes:
1053///   1) instantiating function templates
1054///   2) substituting friend declarations
1055/// FIXME: preserve function definitions in case #2
1056Decl *TemplateDeclInstantiator::VisitFunctionDecl(FunctionDecl *D,
1057                                       TemplateParameterList *TemplateParams) {
1058  // Check whether there is already a function template specialization for
1059  // this declaration.
1060  FunctionTemplateDecl *FunctionTemplate = D->getDescribedFunctionTemplate();
1061  if (FunctionTemplate && !TemplateParams) {
1062    std::pair<const TemplateArgument *, unsigned> Innermost
1063      = TemplateArgs.getInnermost();
1064
1065    void *InsertPos = 0;
1066    FunctionDecl *SpecFunc
1067      = FunctionTemplate->findSpecialization(Innermost.first, Innermost.second,
1068                                             InsertPos);
1069
1070    // If we already have a function template specialization, return it.
1071    if (SpecFunc)
1072      return SpecFunc;
1073  }
1074
1075  bool isFriend;
1076  if (FunctionTemplate)
1077    isFriend = (FunctionTemplate->getFriendObjectKind() != Decl::FOK_None);
1078  else
1079    isFriend = (D->getFriendObjectKind() != Decl::FOK_None);
1080
1081  bool MergeWithParentScope = (TemplateParams != 0) ||
1082    Owner->isFunctionOrMethod() ||
1083    !(isa<Decl>(Owner) &&
1084      cast<Decl>(Owner)->isDefinedOutsideFunctionOrMethod());
1085  LocalInstantiationScope Scope(SemaRef, MergeWithParentScope);
1086
1087  SmallVector<ParmVarDecl *, 4> Params;
1088  TypeSourceInfo *TInfo = SubstFunctionType(D, Params);
1089  if (!TInfo)
1090    return 0;
1091  QualType T = adjustFunctionTypeForInstantiation(SemaRef.Context, D, TInfo);
1092
1093  NestedNameSpecifierLoc QualifierLoc = D->getQualifierLoc();
1094  if (QualifierLoc) {
1095    QualifierLoc = SemaRef.SubstNestedNameSpecifierLoc(QualifierLoc,
1096                                                       TemplateArgs);
1097    if (!QualifierLoc)
1098      return 0;
1099  }
1100
1101  // If we're instantiating a local function declaration, put the result
1102  // in the owner;  otherwise we need to find the instantiated context.
1103  DeclContext *DC;
1104  if (D->getDeclContext()->isFunctionOrMethod())
1105    DC = Owner;
1106  else if (isFriend && QualifierLoc) {
1107    CXXScopeSpec SS;
1108    SS.Adopt(QualifierLoc);
1109    DC = SemaRef.computeDeclContext(SS);
1110    if (!DC) return 0;
1111  } else {
1112    DC = SemaRef.FindInstantiatedContext(D->getLocation(), D->getDeclContext(),
1113                                         TemplateArgs);
1114  }
1115
1116  FunctionDecl *Function =
1117      FunctionDecl::Create(SemaRef.Context, DC, D->getInnerLocStart(),
1118                           D->getNameInfo(), T, TInfo,
1119                           D->getStorageClass(), D->getStorageClassAsWritten(),
1120                           D->isInlineSpecified(), D->hasWrittenPrototype(),
1121                           D->isConstexpr());
1122
1123  if (QualifierLoc)
1124    Function->setQualifierInfo(QualifierLoc);
1125
1126  DeclContext *LexicalDC = Owner;
1127  if (!isFriend && D->isOutOfLine()) {
1128    assert(D->getDeclContext()->isFileContext());
1129    LexicalDC = D->getDeclContext();
1130  }
1131
1132  Function->setLexicalDeclContext(LexicalDC);
1133
1134  // Attach the parameters
1135  if (isa<FunctionProtoType>(Function->getType().IgnoreParens())) {
1136    // Adopt the already-instantiated parameters into our own context.
1137    for (unsigned P = 0; P < Params.size(); ++P)
1138      if (Params[P])
1139        Params[P]->setOwningFunction(Function);
1140  } else {
1141    // Since we were instantiated via a typedef of a function type, create
1142    // new parameters.
1143    const FunctionProtoType *Proto
1144      = Function->getType()->getAs<FunctionProtoType>();
1145    assert(Proto && "No function prototype in template instantiation?");
1146    for (FunctionProtoType::arg_type_iterator AI = Proto->arg_type_begin(),
1147         AE = Proto->arg_type_end(); AI != AE; ++AI) {
1148      ParmVarDecl *Param
1149        = SemaRef.BuildParmVarDeclForTypedef(Function, Function->getLocation(),
1150                                             *AI);
1151      Param->setScopeInfo(0, Params.size());
1152      Params.push_back(Param);
1153    }
1154  }
1155  Function->setParams(Params);
1156
1157  SourceLocation InstantiateAtPOI;
1158  if (TemplateParams) {
1159    // Our resulting instantiation is actually a function template, since we
1160    // are substituting only the outer template parameters. For example, given
1161    //
1162    //   template<typename T>
1163    //   struct X {
1164    //     template<typename U> friend void f(T, U);
1165    //   };
1166    //
1167    //   X<int> x;
1168    //
1169    // We are instantiating the friend function template "f" within X<int>,
1170    // which means substituting int for T, but leaving "f" as a friend function
1171    // template.
1172    // Build the function template itself.
1173    FunctionTemplate = FunctionTemplateDecl::Create(SemaRef.Context, DC,
1174                                                    Function->getLocation(),
1175                                                    Function->getDeclName(),
1176                                                    TemplateParams, Function);
1177    Function->setDescribedFunctionTemplate(FunctionTemplate);
1178
1179    FunctionTemplate->setLexicalDeclContext(LexicalDC);
1180
1181    if (isFriend && D->isThisDeclarationADefinition()) {
1182      // TODO: should we remember this connection regardless of whether
1183      // the friend declaration provided a body?
1184      FunctionTemplate->setInstantiatedFromMemberTemplate(
1185                                           D->getDescribedFunctionTemplate());
1186    }
1187  } else if (FunctionTemplate) {
1188    // Record this function template specialization.
1189    std::pair<const TemplateArgument *, unsigned> Innermost
1190      = TemplateArgs.getInnermost();
1191    Function->setFunctionTemplateSpecialization(FunctionTemplate,
1192                            TemplateArgumentList::CreateCopy(SemaRef.Context,
1193                                                             Innermost.first,
1194                                                             Innermost.second),
1195                                                /*InsertPos=*/0);
1196  } else if (isFriend) {
1197    // Note, we need this connection even if the friend doesn't have a body.
1198    // Its body may exist but not have been attached yet due to deferred
1199    // parsing.
1200    // FIXME: It might be cleaner to set this when attaching the body to the
1201    // friend function declaration, however that would require finding all the
1202    // instantiations and modifying them.
1203    Function->setInstantiationOfMemberFunction(D, TSK_ImplicitInstantiation);
1204  }
1205
1206  if (InitFunctionInstantiation(Function, D))
1207    Function->setInvalidDecl();
1208
1209  bool isExplicitSpecialization = false;
1210
1211  LookupResult Previous(SemaRef, Function->getDeclName(), SourceLocation(),
1212                        Sema::LookupOrdinaryName, Sema::ForRedeclaration);
1213
1214  if (DependentFunctionTemplateSpecializationInfo *Info
1215        = D->getDependentSpecializationInfo()) {
1216    assert(isFriend && "non-friend has dependent specialization info?");
1217
1218    // This needs to be set now for future sanity.
1219    Function->setObjectOfFriendDecl(/*HasPrevious*/ true);
1220
1221    // Instantiate the explicit template arguments.
1222    TemplateArgumentListInfo ExplicitArgs(Info->getLAngleLoc(),
1223                                          Info->getRAngleLoc());
1224    if (SemaRef.Subst(Info->getTemplateArgs(), Info->getNumTemplateArgs(),
1225                      ExplicitArgs, TemplateArgs))
1226      return 0;
1227
1228    // Map the candidate templates to their instantiations.
1229    for (unsigned I = 0, E = Info->getNumTemplates(); I != E; ++I) {
1230      Decl *Temp = SemaRef.FindInstantiatedDecl(D->getLocation(),
1231                                                Info->getTemplate(I),
1232                                                TemplateArgs);
1233      if (!Temp) return 0;
1234
1235      Previous.addDecl(cast<FunctionTemplateDecl>(Temp));
1236    }
1237
1238    if (SemaRef.CheckFunctionTemplateSpecialization(Function,
1239                                                    &ExplicitArgs,
1240                                                    Previous))
1241      Function->setInvalidDecl();
1242
1243    isExplicitSpecialization = true;
1244
1245  } else if (TemplateParams || !FunctionTemplate) {
1246    // Look only into the namespace where the friend would be declared to
1247    // find a previous declaration. This is the innermost enclosing namespace,
1248    // as described in ActOnFriendFunctionDecl.
1249    SemaRef.LookupQualifiedName(Previous, DC);
1250
1251    // In C++, the previous declaration we find might be a tag type
1252    // (class or enum). In this case, the new declaration will hide the
1253    // tag type. Note that this does does not apply if we're declaring a
1254    // typedef (C++ [dcl.typedef]p4).
1255    if (Previous.isSingleTagDecl())
1256      Previous.clear();
1257  }
1258
1259  SemaRef.CheckFunctionDeclaration(/*Scope*/ 0, Function, Previous,
1260                                   isExplicitSpecialization);
1261
1262  NamedDecl *PrincipalDecl = (TemplateParams
1263                              ? cast<NamedDecl>(FunctionTemplate)
1264                              : Function);
1265
1266  // If the original function was part of a friend declaration,
1267  // inherit its namespace state and add it to the owner.
1268  if (isFriend) {
1269    NamedDecl *PrevDecl;
1270    if (TemplateParams)
1271      PrevDecl = FunctionTemplate->getPreviousDecl();
1272    else
1273      PrevDecl = Function->getPreviousDecl();
1274
1275    PrincipalDecl->setObjectOfFriendDecl(PrevDecl != 0);
1276    DC->makeDeclVisibleInContext(PrincipalDecl);
1277
1278    bool queuedInstantiation = false;
1279
1280    // C++98 [temp.friend]p5: When a function is defined in a friend function
1281    //   declaration in a class template, the function is defined at each
1282    //   instantiation of the class template. The function is defined even if it
1283    //   is never used.
1284    // C++11 [temp.friend]p4: When a function is defined in a friend function
1285    //   declaration in a class template, the function is instantiated when the
1286    //   function is odr-used.
1287    //
1288    // If -Wc++98-compat is enabled, we go through the motions of checking for a
1289    // redefinition, but don't instantiate the function.
1290    if ((!SemaRef.getLangOpts().CPlusPlus0x ||
1291         SemaRef.Diags.getDiagnosticLevel(
1292             diag::warn_cxx98_compat_friend_redefinition,
1293             Function->getLocation())
1294           != DiagnosticsEngine::Ignored) &&
1295        D->isThisDeclarationADefinition()) {
1296      // Check for a function body.
1297      const FunctionDecl *Definition = 0;
1298      if (Function->isDefined(Definition) &&
1299          Definition->getTemplateSpecializationKind() == TSK_Undeclared) {
1300        SemaRef.Diag(Function->getLocation(),
1301                     SemaRef.getLangOpts().CPlusPlus0x ?
1302                       diag::warn_cxx98_compat_friend_redefinition :
1303                       diag::err_redefinition) << Function->getDeclName();
1304        SemaRef.Diag(Definition->getLocation(), diag::note_previous_definition);
1305        if (!SemaRef.getLangOpts().CPlusPlus0x)
1306          Function->setInvalidDecl();
1307      }
1308      // Check for redefinitions due to other instantiations of this or
1309      // a similar friend function.
1310      else for (FunctionDecl::redecl_iterator R = Function->redecls_begin(),
1311                                           REnd = Function->redecls_end();
1312                R != REnd; ++R) {
1313        if (*R == Function)
1314          continue;
1315        switch (R->getFriendObjectKind()) {
1316        case Decl::FOK_None:
1317          if (!SemaRef.getLangOpts().CPlusPlus0x &&
1318              !queuedInstantiation && R->isUsed(false)) {
1319            if (MemberSpecializationInfo *MSInfo
1320                = Function->getMemberSpecializationInfo()) {
1321              if (MSInfo->getPointOfInstantiation().isInvalid()) {
1322                SourceLocation Loc = R->getLocation(); // FIXME
1323                MSInfo->setPointOfInstantiation(Loc);
1324                SemaRef.PendingLocalImplicitInstantiations.push_back(
1325                                                 std::make_pair(Function, Loc));
1326                queuedInstantiation = true;
1327              }
1328            }
1329          }
1330          break;
1331        default:
1332          if (const FunctionDecl *RPattern
1333              = R->getTemplateInstantiationPattern())
1334            if (RPattern->isDefined(RPattern)) {
1335              SemaRef.Diag(Function->getLocation(),
1336                           SemaRef.getLangOpts().CPlusPlus0x ?
1337                             diag::warn_cxx98_compat_friend_redefinition :
1338                             diag::err_redefinition)
1339                << Function->getDeclName();
1340              SemaRef.Diag(R->getLocation(), diag::note_previous_definition);
1341              if (!SemaRef.getLangOpts().CPlusPlus0x)
1342                Function->setInvalidDecl();
1343              break;
1344            }
1345        }
1346      }
1347    }
1348  }
1349
1350  if (Function->isOverloadedOperator() && !DC->isRecord() &&
1351      PrincipalDecl->isInIdentifierNamespace(Decl::IDNS_Ordinary))
1352    PrincipalDecl->setNonMemberOperator();
1353
1354  assert(!D->isDefaulted() && "only methods should be defaulted");
1355  return Function;
1356}
1357
1358Decl *
1359TemplateDeclInstantiator::VisitCXXMethodDecl(CXXMethodDecl *D,
1360                                      TemplateParameterList *TemplateParams,
1361                                      bool IsClassScopeSpecialization) {
1362  FunctionTemplateDecl *FunctionTemplate = D->getDescribedFunctionTemplate();
1363  if (FunctionTemplate && !TemplateParams) {
1364    // We are creating a function template specialization from a function
1365    // template. Check whether there is already a function template
1366    // specialization for this particular set of template arguments.
1367    std::pair<const TemplateArgument *, unsigned> Innermost
1368      = TemplateArgs.getInnermost();
1369
1370    void *InsertPos = 0;
1371    FunctionDecl *SpecFunc
1372      = FunctionTemplate->findSpecialization(Innermost.first, Innermost.second,
1373                                             InsertPos);
1374
1375    // If we already have a function template specialization, return it.
1376    if (SpecFunc)
1377      return SpecFunc;
1378  }
1379
1380  bool isFriend;
1381  if (FunctionTemplate)
1382    isFriend = (FunctionTemplate->getFriendObjectKind() != Decl::FOK_None);
1383  else
1384    isFriend = (D->getFriendObjectKind() != Decl::FOK_None);
1385
1386  bool MergeWithParentScope = (TemplateParams != 0) ||
1387    !(isa<Decl>(Owner) &&
1388      cast<Decl>(Owner)->isDefinedOutsideFunctionOrMethod());
1389  LocalInstantiationScope Scope(SemaRef, MergeWithParentScope);
1390
1391  // Instantiate enclosing template arguments for friends.
1392  SmallVector<TemplateParameterList *, 4> TempParamLists;
1393  unsigned NumTempParamLists = 0;
1394  if (isFriend && (NumTempParamLists = D->getNumTemplateParameterLists())) {
1395    TempParamLists.set_size(NumTempParamLists);
1396    for (unsigned I = 0; I != NumTempParamLists; ++I) {
1397      TemplateParameterList *TempParams = D->getTemplateParameterList(I);
1398      TemplateParameterList *InstParams = SubstTemplateParams(TempParams);
1399      if (!InstParams)
1400        return NULL;
1401      TempParamLists[I] = InstParams;
1402    }
1403  }
1404
1405  SmallVector<ParmVarDecl *, 4> Params;
1406  TypeSourceInfo *TInfo = SubstFunctionType(D, Params);
1407  if (!TInfo)
1408    return 0;
1409  QualType T = adjustFunctionTypeForInstantiation(SemaRef.Context, D, TInfo);
1410
1411  // \brief If the type of this function, after ignoring parentheses,
1412  // is not *directly* a function type, then we're instantiating a function
1413  // that was declared via a typedef, e.g.,
1414  //
1415  //   typedef int functype(int, int);
1416  //   functype func;
1417  //
1418  // In this case, we'll just go instantiate the ParmVarDecls that we
1419  // synthesized in the method declaration.
1420  if (!isa<FunctionProtoType>(T.IgnoreParens())) {
1421    assert(!Params.size() && "Instantiating type could not yield parameters");
1422    SmallVector<QualType, 4> ParamTypes;
1423    if (SemaRef.SubstParmTypes(D->getLocation(), D->param_begin(),
1424                               D->getNumParams(), TemplateArgs, ParamTypes,
1425                               &Params))
1426      return 0;
1427  }
1428
1429  NestedNameSpecifierLoc QualifierLoc = D->getQualifierLoc();
1430  if (QualifierLoc) {
1431    QualifierLoc = SemaRef.SubstNestedNameSpecifierLoc(QualifierLoc,
1432                                                 TemplateArgs);
1433    if (!QualifierLoc)
1434      return 0;
1435  }
1436
1437  DeclContext *DC = Owner;
1438  if (isFriend) {
1439    if (QualifierLoc) {
1440      CXXScopeSpec SS;
1441      SS.Adopt(QualifierLoc);
1442      DC = SemaRef.computeDeclContext(SS);
1443
1444      if (DC && SemaRef.RequireCompleteDeclContext(SS, DC))
1445        return 0;
1446    } else {
1447      DC = SemaRef.FindInstantiatedContext(D->getLocation(),
1448                                           D->getDeclContext(),
1449                                           TemplateArgs);
1450    }
1451    if (!DC) return 0;
1452  }
1453
1454  // Build the instantiated method declaration.
1455  CXXRecordDecl *Record = cast<CXXRecordDecl>(DC);
1456  CXXMethodDecl *Method = 0;
1457
1458  SourceLocation StartLoc = D->getInnerLocStart();
1459  DeclarationNameInfo NameInfo
1460    = SemaRef.SubstDeclarationNameInfo(D->getNameInfo(), TemplateArgs);
1461  if (CXXConstructorDecl *Constructor = dyn_cast<CXXConstructorDecl>(D)) {
1462    Method = CXXConstructorDecl::Create(SemaRef.Context, Record,
1463                                        StartLoc, NameInfo, T, TInfo,
1464                                        Constructor->isExplicit(),
1465                                        Constructor->isInlineSpecified(),
1466                                        false, Constructor->isConstexpr());
1467  } else if (CXXDestructorDecl *Destructor = dyn_cast<CXXDestructorDecl>(D)) {
1468    Method = CXXDestructorDecl::Create(SemaRef.Context, Record,
1469                                       StartLoc, NameInfo, T, TInfo,
1470                                       Destructor->isInlineSpecified(),
1471                                       false);
1472  } else if (CXXConversionDecl *Conversion = dyn_cast<CXXConversionDecl>(D)) {
1473    Method = CXXConversionDecl::Create(SemaRef.Context, Record,
1474                                       StartLoc, NameInfo, T, TInfo,
1475                                       Conversion->isInlineSpecified(),
1476                                       Conversion->isExplicit(),
1477                                       Conversion->isConstexpr(),
1478                                       Conversion->getLocEnd());
1479  } else {
1480    Method = CXXMethodDecl::Create(SemaRef.Context, Record,
1481                                   StartLoc, NameInfo, T, TInfo,
1482                                   D->isStatic(),
1483                                   D->getStorageClassAsWritten(),
1484                                   D->isInlineSpecified(),
1485                                   D->isConstexpr(), D->getLocEnd());
1486  }
1487
1488  if (QualifierLoc)
1489    Method->setQualifierInfo(QualifierLoc);
1490
1491  if (TemplateParams) {
1492    // Our resulting instantiation is actually a function template, since we
1493    // are substituting only the outer template parameters. For example, given
1494    //
1495    //   template<typename T>
1496    //   struct X {
1497    //     template<typename U> void f(T, U);
1498    //   };
1499    //
1500    //   X<int> x;
1501    //
1502    // We are instantiating the member template "f" within X<int>, which means
1503    // substituting int for T, but leaving "f" as a member function template.
1504    // Build the function template itself.
1505    FunctionTemplate = FunctionTemplateDecl::Create(SemaRef.Context, Record,
1506                                                    Method->getLocation(),
1507                                                    Method->getDeclName(),
1508                                                    TemplateParams, Method);
1509    if (isFriend) {
1510      FunctionTemplate->setLexicalDeclContext(Owner);
1511      FunctionTemplate->setObjectOfFriendDecl(true);
1512    } else if (D->isOutOfLine())
1513      FunctionTemplate->setLexicalDeclContext(D->getLexicalDeclContext());
1514    Method->setDescribedFunctionTemplate(FunctionTemplate);
1515  } else if (FunctionTemplate) {
1516    // Record this function template specialization.
1517    std::pair<const TemplateArgument *, unsigned> Innermost
1518      = TemplateArgs.getInnermost();
1519    Method->setFunctionTemplateSpecialization(FunctionTemplate,
1520                         TemplateArgumentList::CreateCopy(SemaRef.Context,
1521                                                          Innermost.first,
1522                                                          Innermost.second),
1523                                              /*InsertPos=*/0);
1524  } else if (!isFriend) {
1525    // Record that this is an instantiation of a member function.
1526    Method->setInstantiationOfMemberFunction(D, TSK_ImplicitInstantiation);
1527  }
1528
1529  // If we are instantiating a member function defined
1530  // out-of-line, the instantiation will have the same lexical
1531  // context (which will be a namespace scope) as the template.
1532  if (isFriend) {
1533    if (NumTempParamLists)
1534      Method->setTemplateParameterListsInfo(SemaRef.Context,
1535                                            NumTempParamLists,
1536                                            TempParamLists.data());
1537
1538    Method->setLexicalDeclContext(Owner);
1539    Method->setObjectOfFriendDecl(true);
1540  } else if (D->isOutOfLine())
1541    Method->setLexicalDeclContext(D->getLexicalDeclContext());
1542
1543  // Attach the parameters
1544  for (unsigned P = 0; P < Params.size(); ++P)
1545    Params[P]->setOwningFunction(Method);
1546  Method->setParams(Params);
1547
1548  if (InitMethodInstantiation(Method, D))
1549    Method->setInvalidDecl();
1550
1551  LookupResult Previous(SemaRef, NameInfo, Sema::LookupOrdinaryName,
1552                        Sema::ForRedeclaration);
1553
1554  if (!FunctionTemplate || TemplateParams || isFriend) {
1555    SemaRef.LookupQualifiedName(Previous, Record);
1556
1557    // In C++, the previous declaration we find might be a tag type
1558    // (class or enum). In this case, the new declaration will hide the
1559    // tag type. Note that this does does not apply if we're declaring a
1560    // typedef (C++ [dcl.typedef]p4).
1561    if (Previous.isSingleTagDecl())
1562      Previous.clear();
1563  }
1564
1565  if (!IsClassScopeSpecialization)
1566    SemaRef.CheckFunctionDeclaration(0, Method, Previous, false);
1567
1568  if (D->isPure())
1569    SemaRef.CheckPureMethod(Method, SourceRange());
1570
1571  // Propagate access.  For a non-friend declaration, the access is
1572  // whatever we're propagating from.  For a friend, it should be the
1573  // previous declaration we just found.
1574  if (isFriend && Method->getPreviousDecl())
1575    Method->setAccess(Method->getPreviousDecl()->getAccess());
1576  else
1577    Method->setAccess(D->getAccess());
1578  if (FunctionTemplate)
1579    FunctionTemplate->setAccess(Method->getAccess());
1580
1581  SemaRef.CheckOverrideControl(Method);
1582
1583  // If a function is defined as defaulted or deleted, mark it as such now.
1584  if (D->isDefaulted())
1585    Method->setDefaulted();
1586  if (D->isDeletedAsWritten())
1587    Method->setDeletedAsWritten();
1588
1589  // If there's a function template, let our caller handle it.
1590  if (FunctionTemplate) {
1591    // do nothing
1592
1593  // Don't hide a (potentially) valid declaration with an invalid one.
1594  } else if (Method->isInvalidDecl() && !Previous.empty()) {
1595    // do nothing
1596
1597  // Otherwise, check access to friends and make them visible.
1598  } else if (isFriend) {
1599    // We only need to re-check access for methods which we didn't
1600    // manage to match during parsing.
1601    if (!D->getPreviousDecl())
1602      SemaRef.CheckFriendAccess(Method);
1603
1604    Record->makeDeclVisibleInContext(Method);
1605
1606  // Otherwise, add the declaration.  We don't need to do this for
1607  // class-scope specializations because we'll have matched them with
1608  // the appropriate template.
1609  } else if (!IsClassScopeSpecialization) {
1610    Owner->addDecl(Method);
1611  }
1612
1613  if (D->isExplicitlyDefaulted()) {
1614    SemaRef.SetDeclDefaulted(Method, Method->getLocation());
1615  } else {
1616    assert(!D->isDefaulted() &&
1617           "should not implicitly default uninstantiated function");
1618  }
1619
1620  return Method;
1621}
1622
1623Decl *TemplateDeclInstantiator::VisitCXXConstructorDecl(CXXConstructorDecl *D) {
1624  return VisitCXXMethodDecl(D);
1625}
1626
1627Decl *TemplateDeclInstantiator::VisitCXXDestructorDecl(CXXDestructorDecl *D) {
1628  return VisitCXXMethodDecl(D);
1629}
1630
1631Decl *TemplateDeclInstantiator::VisitCXXConversionDecl(CXXConversionDecl *D) {
1632  return VisitCXXMethodDecl(D);
1633}
1634
1635ParmVarDecl *TemplateDeclInstantiator::VisitParmVarDecl(ParmVarDecl *D) {
1636  return SemaRef.SubstParmVarDecl(D, TemplateArgs, /*indexAdjustment*/ 0,
1637                                  llvm::Optional<unsigned>(),
1638                                  /*ExpectParameterPack=*/false);
1639}
1640
1641Decl *TemplateDeclInstantiator::VisitTemplateTypeParmDecl(
1642                                                    TemplateTypeParmDecl *D) {
1643  // TODO: don't always clone when decls are refcounted.
1644  assert(D->getTypeForDecl()->isTemplateTypeParmType());
1645
1646  TemplateTypeParmDecl *Inst =
1647    TemplateTypeParmDecl::Create(SemaRef.Context, Owner,
1648                                 D->getLocStart(), D->getLocation(),
1649                                 D->getDepth() - TemplateArgs.getNumLevels(),
1650                                 D->getIndex(), D->getIdentifier(),
1651                                 D->wasDeclaredWithTypename(),
1652                                 D->isParameterPack());
1653  Inst->setAccess(AS_public);
1654
1655  if (D->hasDefaultArgument())
1656    Inst->setDefaultArgument(D->getDefaultArgumentInfo(), false);
1657
1658  // Introduce this template parameter's instantiation into the instantiation
1659  // scope.
1660  SemaRef.CurrentInstantiationScope->InstantiatedLocal(D, Inst);
1661
1662  return Inst;
1663}
1664
1665Decl *TemplateDeclInstantiator::VisitNonTypeTemplateParmDecl(
1666                                                 NonTypeTemplateParmDecl *D) {
1667  // Substitute into the type of the non-type template parameter.
1668  TypeLoc TL = D->getTypeSourceInfo()->getTypeLoc();
1669  SmallVector<TypeSourceInfo *, 4> ExpandedParameterPackTypesAsWritten;
1670  SmallVector<QualType, 4> ExpandedParameterPackTypes;
1671  bool IsExpandedParameterPack = false;
1672  TypeSourceInfo *DI;
1673  QualType T;
1674  bool Invalid = false;
1675
1676  if (D->isExpandedParameterPack()) {
1677    // The non-type template parameter pack is an already-expanded pack
1678    // expansion of types. Substitute into each of the expanded types.
1679    ExpandedParameterPackTypes.reserve(D->getNumExpansionTypes());
1680    ExpandedParameterPackTypesAsWritten.reserve(D->getNumExpansionTypes());
1681    for (unsigned I = 0, N = D->getNumExpansionTypes(); I != N; ++I) {
1682      TypeSourceInfo *NewDI =SemaRef.SubstType(D->getExpansionTypeSourceInfo(I),
1683                                               TemplateArgs,
1684                                               D->getLocation(),
1685                                               D->getDeclName());
1686      if (!NewDI)
1687        return 0;
1688
1689      ExpandedParameterPackTypesAsWritten.push_back(NewDI);
1690      QualType NewT =SemaRef.CheckNonTypeTemplateParameterType(NewDI->getType(),
1691                                                              D->getLocation());
1692      if (NewT.isNull())
1693        return 0;
1694      ExpandedParameterPackTypes.push_back(NewT);
1695    }
1696
1697    IsExpandedParameterPack = true;
1698    DI = D->getTypeSourceInfo();
1699    T = DI->getType();
1700  } else if (D->isPackExpansion()) {
1701    // The non-type template parameter pack's type is a pack expansion of types.
1702    // Determine whether we need to expand this parameter pack into separate
1703    // types.
1704    PackExpansionTypeLoc Expansion = cast<PackExpansionTypeLoc>(TL);
1705    TypeLoc Pattern = Expansion.getPatternLoc();
1706    SmallVector<UnexpandedParameterPack, 2> Unexpanded;
1707    SemaRef.collectUnexpandedParameterPacks(Pattern, Unexpanded);
1708
1709    // Determine whether the set of unexpanded parameter packs can and should
1710    // be expanded.
1711    bool Expand = true;
1712    bool RetainExpansion = false;
1713    llvm::Optional<unsigned> OrigNumExpansions
1714      = Expansion.getTypePtr()->getNumExpansions();
1715    llvm::Optional<unsigned> NumExpansions = OrigNumExpansions;
1716    if (SemaRef.CheckParameterPacksForExpansion(Expansion.getEllipsisLoc(),
1717                                                Pattern.getSourceRange(),
1718                                                Unexpanded,
1719                                                TemplateArgs,
1720                                                Expand, RetainExpansion,
1721                                                NumExpansions))
1722      return 0;
1723
1724    if (Expand) {
1725      for (unsigned I = 0; I != *NumExpansions; ++I) {
1726        Sema::ArgumentPackSubstitutionIndexRAII SubstIndex(SemaRef, I);
1727        TypeSourceInfo *NewDI = SemaRef.SubstType(Pattern, TemplateArgs,
1728                                                  D->getLocation(),
1729                                                  D->getDeclName());
1730        if (!NewDI)
1731          return 0;
1732
1733        ExpandedParameterPackTypesAsWritten.push_back(NewDI);
1734        QualType NewT = SemaRef.CheckNonTypeTemplateParameterType(
1735                                                              NewDI->getType(),
1736                                                              D->getLocation());
1737        if (NewT.isNull())
1738          return 0;
1739        ExpandedParameterPackTypes.push_back(NewT);
1740      }
1741
1742      // Note that we have an expanded parameter pack. The "type" of this
1743      // expanded parameter pack is the original expansion type, but callers
1744      // will end up using the expanded parameter pack types for type-checking.
1745      IsExpandedParameterPack = true;
1746      DI = D->getTypeSourceInfo();
1747      T = DI->getType();
1748    } else {
1749      // We cannot fully expand the pack expansion now, so substitute into the
1750      // pattern and create a new pack expansion type.
1751      Sema::ArgumentPackSubstitutionIndexRAII SubstIndex(SemaRef, -1);
1752      TypeSourceInfo *NewPattern = SemaRef.SubstType(Pattern, TemplateArgs,
1753                                                     D->getLocation(),
1754                                                     D->getDeclName());
1755      if (!NewPattern)
1756        return 0;
1757
1758      DI = SemaRef.CheckPackExpansion(NewPattern, Expansion.getEllipsisLoc(),
1759                                      NumExpansions);
1760      if (!DI)
1761        return 0;
1762
1763      T = DI->getType();
1764    }
1765  } else {
1766    // Simple case: substitution into a parameter that is not a parameter pack.
1767    DI = SemaRef.SubstType(D->getTypeSourceInfo(), TemplateArgs,
1768                           D->getLocation(), D->getDeclName());
1769    if (!DI)
1770      return 0;
1771
1772    // Check that this type is acceptable for a non-type template parameter.
1773    T = SemaRef.CheckNonTypeTemplateParameterType(DI->getType(),
1774                                                  D->getLocation());
1775    if (T.isNull()) {
1776      T = SemaRef.Context.IntTy;
1777      Invalid = true;
1778    }
1779  }
1780
1781  NonTypeTemplateParmDecl *Param;
1782  if (IsExpandedParameterPack)
1783    Param = NonTypeTemplateParmDecl::Create(SemaRef.Context, Owner,
1784                                            D->getInnerLocStart(),
1785                                            D->getLocation(),
1786                                    D->getDepth() - TemplateArgs.getNumLevels(),
1787                                            D->getPosition(),
1788                                            D->getIdentifier(), T,
1789                                            DI,
1790                                            ExpandedParameterPackTypes.data(),
1791                                            ExpandedParameterPackTypes.size(),
1792                                    ExpandedParameterPackTypesAsWritten.data());
1793  else
1794    Param = NonTypeTemplateParmDecl::Create(SemaRef.Context, Owner,
1795                                            D->getInnerLocStart(),
1796                                            D->getLocation(),
1797                                    D->getDepth() - TemplateArgs.getNumLevels(),
1798                                            D->getPosition(),
1799                                            D->getIdentifier(), T,
1800                                            D->isParameterPack(), DI);
1801
1802  Param->setAccess(AS_public);
1803  if (Invalid)
1804    Param->setInvalidDecl();
1805
1806  Param->setDefaultArgument(D->getDefaultArgument(), false);
1807
1808  // Introduce this template parameter's instantiation into the instantiation
1809  // scope.
1810  SemaRef.CurrentInstantiationScope->InstantiatedLocal(D, Param);
1811  return Param;
1812}
1813
1814static void collectUnexpandedParameterPacks(
1815    Sema &S,
1816    TemplateParameterList *Params,
1817    SmallVectorImpl<UnexpandedParameterPack> &Unexpanded) {
1818  for (TemplateParameterList::const_iterator I = Params->begin(),
1819                                             E = Params->end(); I != E; ++I) {
1820    if ((*I)->isTemplateParameterPack())
1821      continue;
1822    if (NonTypeTemplateParmDecl *NTTP = dyn_cast<NonTypeTemplateParmDecl>(*I))
1823      S.collectUnexpandedParameterPacks(NTTP->getTypeSourceInfo()->getTypeLoc(),
1824                                        Unexpanded);
1825    if (TemplateTemplateParmDecl *TTP = dyn_cast<TemplateTemplateParmDecl>(*I))
1826      collectUnexpandedParameterPacks(S, TTP->getTemplateParameters(),
1827                                      Unexpanded);
1828  }
1829}
1830
1831Decl *
1832TemplateDeclInstantiator::VisitTemplateTemplateParmDecl(
1833                                                  TemplateTemplateParmDecl *D) {
1834  // Instantiate the template parameter list of the template template parameter.
1835  TemplateParameterList *TempParams = D->getTemplateParameters();
1836  TemplateParameterList *InstParams;
1837  SmallVector<TemplateParameterList*, 8> ExpandedParams;
1838
1839  bool IsExpandedParameterPack = false;
1840
1841  if (D->isExpandedParameterPack()) {
1842    // The template template parameter pack is an already-expanded pack
1843    // expansion of template parameters. Substitute into each of the expanded
1844    // parameters.
1845    ExpandedParams.reserve(D->getNumExpansionTemplateParameters());
1846    for (unsigned I = 0, N = D->getNumExpansionTemplateParameters();
1847         I != N; ++I) {
1848      LocalInstantiationScope Scope(SemaRef);
1849      TemplateParameterList *Expansion =
1850        SubstTemplateParams(D->getExpansionTemplateParameters(I));
1851      if (!Expansion)
1852        return 0;
1853      ExpandedParams.push_back(Expansion);
1854    }
1855
1856    IsExpandedParameterPack = true;
1857    InstParams = TempParams;
1858  } else if (D->isPackExpansion()) {
1859    // The template template parameter pack expands to a pack of template
1860    // template parameters. Determine whether we need to expand this parameter
1861    // pack into separate parameters.
1862    SmallVector<UnexpandedParameterPack, 2> Unexpanded;
1863    collectUnexpandedParameterPacks(SemaRef, D->getTemplateParameters(),
1864                                    Unexpanded);
1865
1866    // Determine whether the set of unexpanded parameter packs can and should
1867    // be expanded.
1868    bool Expand = true;
1869    bool RetainExpansion = false;
1870    llvm::Optional<unsigned> NumExpansions;
1871    if (SemaRef.CheckParameterPacksForExpansion(D->getLocation(),
1872                                                TempParams->getSourceRange(),
1873                                                Unexpanded,
1874                                                TemplateArgs,
1875                                                Expand, RetainExpansion,
1876                                                NumExpansions))
1877      return 0;
1878
1879    if (Expand) {
1880      for (unsigned I = 0; I != *NumExpansions; ++I) {
1881        Sema::ArgumentPackSubstitutionIndexRAII SubstIndex(SemaRef, I);
1882        LocalInstantiationScope Scope(SemaRef);
1883        TemplateParameterList *Expansion = SubstTemplateParams(TempParams);
1884        if (!Expansion)
1885          return 0;
1886        ExpandedParams.push_back(Expansion);
1887      }
1888
1889      // Note that we have an expanded parameter pack. The "type" of this
1890      // expanded parameter pack is the original expansion type, but callers
1891      // will end up using the expanded parameter pack types for type-checking.
1892      IsExpandedParameterPack = true;
1893      InstParams = TempParams;
1894    } else {
1895      // We cannot fully expand the pack expansion now, so just substitute
1896      // into the pattern.
1897      Sema::ArgumentPackSubstitutionIndexRAII SubstIndex(SemaRef, -1);
1898
1899      LocalInstantiationScope Scope(SemaRef);
1900      InstParams = SubstTemplateParams(TempParams);
1901      if (!InstParams)
1902        return 0;
1903    }
1904  } else {
1905    // Perform the actual substitution of template parameters within a new,
1906    // local instantiation scope.
1907    LocalInstantiationScope Scope(SemaRef);
1908    InstParams = SubstTemplateParams(TempParams);
1909    if (!InstParams)
1910      return 0;
1911  }
1912
1913  // Build the template template parameter.
1914  TemplateTemplateParmDecl *Param;
1915  if (IsExpandedParameterPack)
1916    Param = TemplateTemplateParmDecl::Create(SemaRef.Context, Owner,
1917                                             D->getLocation(),
1918                                   D->getDepth() - TemplateArgs.getNumLevels(),
1919                                             D->getPosition(),
1920                                             D->getIdentifier(), InstParams,
1921                                             ExpandedParams);
1922  else
1923    Param = TemplateTemplateParmDecl::Create(SemaRef.Context, Owner,
1924                                             D->getLocation(),
1925                                   D->getDepth() - TemplateArgs.getNumLevels(),
1926                                             D->getPosition(),
1927                                             D->isParameterPack(),
1928                                             D->getIdentifier(), InstParams);
1929  Param->setDefaultArgument(D->getDefaultArgument(), false);
1930  Param->setAccess(AS_public);
1931
1932  // Introduce this template parameter's instantiation into the instantiation
1933  // scope.
1934  SemaRef.CurrentInstantiationScope->InstantiatedLocal(D, Param);
1935
1936  return Param;
1937}
1938
1939Decl *TemplateDeclInstantiator::VisitUsingDirectiveDecl(UsingDirectiveDecl *D) {
1940  // Using directives are never dependent (and never contain any types or
1941  // expressions), so they require no explicit instantiation work.
1942
1943  UsingDirectiveDecl *Inst
1944    = UsingDirectiveDecl::Create(SemaRef.Context, Owner, D->getLocation(),
1945                                 D->getNamespaceKeyLocation(),
1946                                 D->getQualifierLoc(),
1947                                 D->getIdentLocation(),
1948                                 D->getNominatedNamespace(),
1949                                 D->getCommonAncestor());
1950
1951  // Add the using directive to its declaration context
1952  // only if this is not a function or method.
1953  if (!Owner->isFunctionOrMethod())
1954    Owner->addDecl(Inst);
1955
1956  return Inst;
1957}
1958
1959Decl *TemplateDeclInstantiator::VisitUsingDecl(UsingDecl *D) {
1960
1961  // The nested name specifier may be dependent, for example
1962  //     template <typename T> struct t {
1963  //       struct s1 { T f1(); };
1964  //       struct s2 : s1 { using s1::f1; };
1965  //     };
1966  //     template struct t<int>;
1967  // Here, in using s1::f1, s1 refers to t<T>::s1;
1968  // we need to substitute for t<int>::s1.
1969  NestedNameSpecifierLoc QualifierLoc
1970    = SemaRef.SubstNestedNameSpecifierLoc(D->getQualifierLoc(),
1971                                          TemplateArgs);
1972  if (!QualifierLoc)
1973    return 0;
1974
1975  // The name info is non-dependent, so no transformation
1976  // is required.
1977  DeclarationNameInfo NameInfo = D->getNameInfo();
1978
1979  // We only need to do redeclaration lookups if we're in a class
1980  // scope (in fact, it's not really even possible in non-class
1981  // scopes).
1982  bool CheckRedeclaration = Owner->isRecord();
1983
1984  LookupResult Prev(SemaRef, NameInfo, Sema::LookupUsingDeclName,
1985                    Sema::ForRedeclaration);
1986
1987  UsingDecl *NewUD = UsingDecl::Create(SemaRef.Context, Owner,
1988                                       D->getUsingLocation(),
1989                                       QualifierLoc,
1990                                       NameInfo,
1991                                       D->isTypeName());
1992
1993  CXXScopeSpec SS;
1994  SS.Adopt(QualifierLoc);
1995  if (CheckRedeclaration) {
1996    Prev.setHideTags(false);
1997    SemaRef.LookupQualifiedName(Prev, Owner);
1998
1999    // Check for invalid redeclarations.
2000    if (SemaRef.CheckUsingDeclRedeclaration(D->getUsingLocation(),
2001                                            D->isTypeName(), SS,
2002                                            D->getLocation(), Prev))
2003      NewUD->setInvalidDecl();
2004
2005  }
2006
2007  if (!NewUD->isInvalidDecl() &&
2008      SemaRef.CheckUsingDeclQualifier(D->getUsingLocation(), SS,
2009                                      D->getLocation()))
2010    NewUD->setInvalidDecl();
2011
2012  SemaRef.Context.setInstantiatedFromUsingDecl(NewUD, D);
2013  NewUD->setAccess(D->getAccess());
2014  Owner->addDecl(NewUD);
2015
2016  // Don't process the shadow decls for an invalid decl.
2017  if (NewUD->isInvalidDecl())
2018    return NewUD;
2019
2020  if (NameInfo.getName().getNameKind() == DeclarationName::CXXConstructorName) {
2021    if (SemaRef.CheckInheritingConstructorUsingDecl(NewUD))
2022      NewUD->setInvalidDecl();
2023    return NewUD;
2024  }
2025
2026  bool isFunctionScope = Owner->isFunctionOrMethod();
2027
2028  // Process the shadow decls.
2029  for (UsingDecl::shadow_iterator I = D->shadow_begin(), E = D->shadow_end();
2030         I != E; ++I) {
2031    UsingShadowDecl *Shadow = *I;
2032    NamedDecl *InstTarget =
2033      cast_or_null<NamedDecl>(SemaRef.FindInstantiatedDecl(
2034                                                          Shadow->getLocation(),
2035                                                        Shadow->getTargetDecl(),
2036                                                           TemplateArgs));
2037    if (!InstTarget)
2038      return 0;
2039
2040    if (CheckRedeclaration &&
2041        SemaRef.CheckUsingShadowDecl(NewUD, InstTarget, Prev))
2042      continue;
2043
2044    UsingShadowDecl *InstShadow
2045      = SemaRef.BuildUsingShadowDecl(/*Scope*/ 0, NewUD, InstTarget);
2046    SemaRef.Context.setInstantiatedFromUsingShadowDecl(InstShadow, Shadow);
2047
2048    if (isFunctionScope)
2049      SemaRef.CurrentInstantiationScope->InstantiatedLocal(Shadow, InstShadow);
2050  }
2051
2052  return NewUD;
2053}
2054
2055Decl *TemplateDeclInstantiator::VisitUsingShadowDecl(UsingShadowDecl *D) {
2056  // Ignore these;  we handle them in bulk when processing the UsingDecl.
2057  return 0;
2058}
2059
2060Decl * TemplateDeclInstantiator
2061    ::VisitUnresolvedUsingTypenameDecl(UnresolvedUsingTypenameDecl *D) {
2062  NestedNameSpecifierLoc QualifierLoc
2063    = SemaRef.SubstNestedNameSpecifierLoc(D->getQualifierLoc(),
2064                                          TemplateArgs);
2065  if (!QualifierLoc)
2066    return 0;
2067
2068  CXXScopeSpec SS;
2069  SS.Adopt(QualifierLoc);
2070
2071  // Since NameInfo refers to a typename, it cannot be a C++ special name.
2072  // Hence, no tranformation is required for it.
2073  DeclarationNameInfo NameInfo(D->getDeclName(), D->getLocation());
2074  NamedDecl *UD =
2075    SemaRef.BuildUsingDeclaration(/*Scope*/ 0, D->getAccess(),
2076                                  D->getUsingLoc(), SS, NameInfo, 0,
2077                                  /*instantiation*/ true,
2078                                  /*typename*/ true, D->getTypenameLoc());
2079  if (UD)
2080    SemaRef.Context.setInstantiatedFromUsingDecl(cast<UsingDecl>(UD), D);
2081
2082  return UD;
2083}
2084
2085Decl * TemplateDeclInstantiator
2086    ::VisitUnresolvedUsingValueDecl(UnresolvedUsingValueDecl *D) {
2087  NestedNameSpecifierLoc QualifierLoc
2088      = SemaRef.SubstNestedNameSpecifierLoc(D->getQualifierLoc(), TemplateArgs);
2089  if (!QualifierLoc)
2090    return 0;
2091
2092  CXXScopeSpec SS;
2093  SS.Adopt(QualifierLoc);
2094
2095  DeclarationNameInfo NameInfo
2096    = SemaRef.SubstDeclarationNameInfo(D->getNameInfo(), TemplateArgs);
2097
2098  NamedDecl *UD =
2099    SemaRef.BuildUsingDeclaration(/*Scope*/ 0, D->getAccess(),
2100                                  D->getUsingLoc(), SS, NameInfo, 0,
2101                                  /*instantiation*/ true,
2102                                  /*typename*/ false, SourceLocation());
2103  if (UD)
2104    SemaRef.Context.setInstantiatedFromUsingDecl(cast<UsingDecl>(UD), D);
2105
2106  return UD;
2107}
2108
2109
2110Decl *TemplateDeclInstantiator::VisitClassScopeFunctionSpecializationDecl(
2111                                     ClassScopeFunctionSpecializationDecl *Decl) {
2112  CXXMethodDecl *OldFD = Decl->getSpecialization();
2113  CXXMethodDecl *NewFD = cast<CXXMethodDecl>(VisitCXXMethodDecl(OldFD,
2114                                                                0, true));
2115
2116  LookupResult Previous(SemaRef, NewFD->getNameInfo(), Sema::LookupOrdinaryName,
2117                        Sema::ForRedeclaration);
2118
2119  TemplateArgumentListInfo TemplateArgs;
2120  TemplateArgumentListInfo* TemplateArgsPtr = 0;
2121  if (Decl->hasExplicitTemplateArgs()) {
2122    TemplateArgs = Decl->templateArgs();
2123    TemplateArgsPtr = &TemplateArgs;
2124  }
2125
2126  SemaRef.LookupQualifiedName(Previous, SemaRef.CurContext);
2127  if (SemaRef.CheckFunctionTemplateSpecialization(NewFD, TemplateArgsPtr,
2128                                                  Previous)) {
2129    NewFD->setInvalidDecl();
2130    return NewFD;
2131  }
2132
2133  // Associate the specialization with the pattern.
2134  FunctionDecl *Specialization = cast<FunctionDecl>(Previous.getFoundDecl());
2135  assert(Specialization && "Class scope Specialization is null");
2136  SemaRef.Context.setClassScopeSpecializationPattern(Specialization, OldFD);
2137
2138  return NewFD;
2139}
2140
2141Decl *Sema::SubstDecl(Decl *D, DeclContext *Owner,
2142                      const MultiLevelTemplateArgumentList &TemplateArgs) {
2143  TemplateDeclInstantiator Instantiator(*this, Owner, TemplateArgs);
2144  if (D->isInvalidDecl())
2145    return 0;
2146
2147  return Instantiator.Visit(D);
2148}
2149
2150/// \brief Instantiates a nested template parameter list in the current
2151/// instantiation context.
2152///
2153/// \param L The parameter list to instantiate
2154///
2155/// \returns NULL if there was an error
2156TemplateParameterList *
2157TemplateDeclInstantiator::SubstTemplateParams(TemplateParameterList *L) {
2158  // Get errors for all the parameters before bailing out.
2159  bool Invalid = false;
2160
2161  unsigned N = L->size();
2162  typedef SmallVector<NamedDecl *, 8> ParamVector;
2163  ParamVector Params;
2164  Params.reserve(N);
2165  for (TemplateParameterList::iterator PI = L->begin(), PE = L->end();
2166       PI != PE; ++PI) {
2167    NamedDecl *D = cast_or_null<NamedDecl>(Visit(*PI));
2168    Params.push_back(D);
2169    Invalid = Invalid || !D || D->isInvalidDecl();
2170  }
2171
2172  // Clean up if we had an error.
2173  if (Invalid)
2174    return NULL;
2175
2176  TemplateParameterList *InstL
2177    = TemplateParameterList::Create(SemaRef.Context, L->getTemplateLoc(),
2178                                    L->getLAngleLoc(), &Params.front(), N,
2179                                    L->getRAngleLoc());
2180  return InstL;
2181}
2182
2183/// \brief Instantiate the declaration of a class template partial
2184/// specialization.
2185///
2186/// \param ClassTemplate the (instantiated) class template that is partially
2187// specialized by the instantiation of \p PartialSpec.
2188///
2189/// \param PartialSpec the (uninstantiated) class template partial
2190/// specialization that we are instantiating.
2191///
2192/// \returns The instantiated partial specialization, if successful; otherwise,
2193/// NULL to indicate an error.
2194ClassTemplatePartialSpecializationDecl *
2195TemplateDeclInstantiator::InstantiateClassTemplatePartialSpecialization(
2196                                            ClassTemplateDecl *ClassTemplate,
2197                          ClassTemplatePartialSpecializationDecl *PartialSpec) {
2198  // Create a local instantiation scope for this class template partial
2199  // specialization, which will contain the instantiations of the template
2200  // parameters.
2201  LocalInstantiationScope Scope(SemaRef);
2202
2203  // Substitute into the template parameters of the class template partial
2204  // specialization.
2205  TemplateParameterList *TempParams = PartialSpec->getTemplateParameters();
2206  TemplateParameterList *InstParams = SubstTemplateParams(TempParams);
2207  if (!InstParams)
2208    return 0;
2209
2210  // Substitute into the template arguments of the class template partial
2211  // specialization.
2212  TemplateArgumentListInfo InstTemplateArgs; // no angle locations
2213  if (SemaRef.Subst(PartialSpec->getTemplateArgsAsWritten(),
2214                    PartialSpec->getNumTemplateArgsAsWritten(),
2215                    InstTemplateArgs, TemplateArgs))
2216    return 0;
2217
2218  // Check that the template argument list is well-formed for this
2219  // class template.
2220  SmallVector<TemplateArgument, 4> Converted;
2221  if (SemaRef.CheckTemplateArgumentList(ClassTemplate,
2222                                        PartialSpec->getLocation(),
2223                                        InstTemplateArgs,
2224                                        false,
2225                                        Converted))
2226    return 0;
2227
2228  // Figure out where to insert this class template partial specialization
2229  // in the member template's set of class template partial specializations.
2230  void *InsertPos = 0;
2231  ClassTemplateSpecializationDecl *PrevDecl
2232    = ClassTemplate->findPartialSpecialization(Converted.data(),
2233                                               Converted.size(), InsertPos);
2234
2235  // Build the canonical type that describes the converted template
2236  // arguments of the class template partial specialization.
2237  QualType CanonType
2238    = SemaRef.Context.getTemplateSpecializationType(TemplateName(ClassTemplate),
2239                                                    Converted.data(),
2240                                                    Converted.size());
2241
2242  // Build the fully-sugared type for this class template
2243  // specialization as the user wrote in the specialization
2244  // itself. This means that we'll pretty-print the type retrieved
2245  // from the specialization's declaration the way that the user
2246  // actually wrote the specialization, rather than formatting the
2247  // name based on the "canonical" representation used to store the
2248  // template arguments in the specialization.
2249  TypeSourceInfo *WrittenTy
2250    = SemaRef.Context.getTemplateSpecializationTypeInfo(
2251                                                    TemplateName(ClassTemplate),
2252                                                    PartialSpec->getLocation(),
2253                                                    InstTemplateArgs,
2254                                                    CanonType);
2255
2256  if (PrevDecl) {
2257    // We've already seen a partial specialization with the same template
2258    // parameters and template arguments. This can happen, for example, when
2259    // substituting the outer template arguments ends up causing two
2260    // class template partial specializations of a member class template
2261    // to have identical forms, e.g.,
2262    //
2263    //   template<typename T, typename U>
2264    //   struct Outer {
2265    //     template<typename X, typename Y> struct Inner;
2266    //     template<typename Y> struct Inner<T, Y>;
2267    //     template<typename Y> struct Inner<U, Y>;
2268    //   };
2269    //
2270    //   Outer<int, int> outer; // error: the partial specializations of Inner
2271    //                          // have the same signature.
2272    SemaRef.Diag(PartialSpec->getLocation(), diag::err_partial_spec_redeclared)
2273      << WrittenTy->getType();
2274    SemaRef.Diag(PrevDecl->getLocation(), diag::note_prev_partial_spec_here)
2275      << SemaRef.Context.getTypeDeclType(PrevDecl);
2276    return 0;
2277  }
2278
2279
2280  // Create the class template partial specialization declaration.
2281  ClassTemplatePartialSpecializationDecl *InstPartialSpec
2282    = ClassTemplatePartialSpecializationDecl::Create(SemaRef.Context,
2283                                                     PartialSpec->getTagKind(),
2284                                                     Owner,
2285                                                     PartialSpec->getLocStart(),
2286                                                     PartialSpec->getLocation(),
2287                                                     InstParams,
2288                                                     ClassTemplate,
2289                                                     Converted.data(),
2290                                                     Converted.size(),
2291                                                     InstTemplateArgs,
2292                                                     CanonType,
2293                                                     0,
2294                             ClassTemplate->getNextPartialSpecSequenceNumber());
2295  // Substitute the nested name specifier, if any.
2296  if (SubstQualifier(PartialSpec, InstPartialSpec))
2297    return 0;
2298
2299  InstPartialSpec->setInstantiatedFromMember(PartialSpec);
2300  InstPartialSpec->setTypeAsWritten(WrittenTy);
2301
2302  // Add this partial specialization to the set of class template partial
2303  // specializations.
2304  ClassTemplate->AddPartialSpecialization(InstPartialSpec, /*InsertPos=*/0);
2305  return InstPartialSpec;
2306}
2307
2308TypeSourceInfo*
2309TemplateDeclInstantiator::SubstFunctionType(FunctionDecl *D,
2310                              SmallVectorImpl<ParmVarDecl *> &Params) {
2311  TypeSourceInfo *OldTInfo = D->getTypeSourceInfo();
2312  assert(OldTInfo && "substituting function without type source info");
2313  assert(Params.empty() && "parameter vector is non-empty at start");
2314
2315  CXXRecordDecl *ThisContext = 0;
2316  unsigned ThisTypeQuals = 0;
2317  if (CXXMethodDecl *Method = dyn_cast<CXXMethodDecl>(D)) {
2318    ThisContext = Method->getParent();
2319    ThisTypeQuals = Method->getTypeQualifiers();
2320  }
2321
2322  TypeSourceInfo *NewTInfo
2323    = SemaRef.SubstFunctionDeclType(OldTInfo, TemplateArgs,
2324                                    D->getTypeSpecStartLoc(),
2325                                    D->getDeclName(),
2326                                    ThisContext, ThisTypeQuals);
2327  if (!NewTInfo)
2328    return 0;
2329
2330  if (NewTInfo != OldTInfo) {
2331    // Get parameters from the new type info.
2332    TypeLoc OldTL = OldTInfo->getTypeLoc().IgnoreParens();
2333    if (FunctionProtoTypeLoc *OldProtoLoc
2334                                  = dyn_cast<FunctionProtoTypeLoc>(&OldTL)) {
2335      TypeLoc NewTL = NewTInfo->getTypeLoc().IgnoreParens();
2336      FunctionProtoTypeLoc *NewProtoLoc = cast<FunctionProtoTypeLoc>(&NewTL);
2337      assert(NewProtoLoc && "Missing prototype?");
2338      unsigned NewIdx = 0;
2339      for (unsigned OldIdx = 0, NumOldParams = OldProtoLoc->getNumArgs();
2340           OldIdx != NumOldParams; ++OldIdx) {
2341        ParmVarDecl *OldParam = OldProtoLoc->getArg(OldIdx);
2342        LocalInstantiationScope *Scope = SemaRef.CurrentInstantiationScope;
2343
2344        llvm::Optional<unsigned> NumArgumentsInExpansion;
2345        if (OldParam->isParameterPack())
2346          NumArgumentsInExpansion =
2347              SemaRef.getNumArgumentsInExpansion(OldParam->getType(),
2348                                                 TemplateArgs);
2349        if (!NumArgumentsInExpansion) {
2350          // Simple case: normal parameter, or a parameter pack that's
2351          // instantiated to a (still-dependent) parameter pack.
2352          ParmVarDecl *NewParam = NewProtoLoc->getArg(NewIdx++);
2353          Params.push_back(NewParam);
2354          Scope->InstantiatedLocal(OldParam, NewParam);
2355        } else {
2356          // Parameter pack expansion: make the instantiation an argument pack.
2357          Scope->MakeInstantiatedLocalArgPack(OldParam);
2358          for (unsigned I = 0; I != *NumArgumentsInExpansion; ++I) {
2359            ParmVarDecl *NewParam = NewProtoLoc->getArg(NewIdx++);
2360            Params.push_back(NewParam);
2361            Scope->InstantiatedLocalPackArg(OldParam, NewParam);
2362          }
2363        }
2364      }
2365    }
2366  } else {
2367    // The function type itself was not dependent and therefore no
2368    // substitution occurred. However, we still need to instantiate
2369    // the function parameters themselves.
2370    TypeLoc OldTL = OldTInfo->getTypeLoc().IgnoreParens();
2371    if (FunctionProtoTypeLoc *OldProtoLoc
2372                                    = dyn_cast<FunctionProtoTypeLoc>(&OldTL)) {
2373      for (unsigned i = 0, i_end = OldProtoLoc->getNumArgs(); i != i_end; ++i) {
2374        ParmVarDecl *Parm = VisitParmVarDecl(OldProtoLoc->getArg(i));
2375        if (!Parm)
2376          return 0;
2377        Params.push_back(Parm);
2378      }
2379    }
2380  }
2381  return NewTInfo;
2382}
2383
2384/// Introduce the instantiated function parameters into the local
2385/// instantiation scope, and set the parameter names to those used
2386/// in the template.
2387static void addInstantiatedParametersToScope(Sema &S, FunctionDecl *Function,
2388                                             const FunctionDecl *PatternDecl,
2389                                             LocalInstantiationScope &Scope,
2390                           const MultiLevelTemplateArgumentList &TemplateArgs) {
2391  unsigned FParamIdx = 0;
2392  for (unsigned I = 0, N = PatternDecl->getNumParams(); I != N; ++I) {
2393    const ParmVarDecl *PatternParam = PatternDecl->getParamDecl(I);
2394    if (!PatternParam->isParameterPack()) {
2395      // Simple case: not a parameter pack.
2396      assert(FParamIdx < Function->getNumParams());
2397      ParmVarDecl *FunctionParam = Function->getParamDecl(FParamIdx);
2398      FunctionParam->setDeclName(PatternParam->getDeclName());
2399      Scope.InstantiatedLocal(PatternParam, FunctionParam);
2400      ++FParamIdx;
2401      continue;
2402    }
2403
2404    // Expand the parameter pack.
2405    Scope.MakeInstantiatedLocalArgPack(PatternParam);
2406    llvm::Optional<unsigned> NumArgumentsInExpansion
2407      = S.getNumArgumentsInExpansion(PatternParam->getType(), TemplateArgs);
2408    assert(NumArgumentsInExpansion &&
2409           "should only be called when all template arguments are known");
2410    for (unsigned Arg = 0; Arg < *NumArgumentsInExpansion; ++Arg) {
2411      ParmVarDecl *FunctionParam = Function->getParamDecl(FParamIdx);
2412      FunctionParam->setDeclName(PatternParam->getDeclName());
2413      Scope.InstantiatedLocalPackArg(PatternParam, FunctionParam);
2414      ++FParamIdx;
2415    }
2416  }
2417}
2418
2419static void InstantiateExceptionSpec(Sema &SemaRef, FunctionDecl *New,
2420                                     const FunctionProtoType *Proto,
2421                           const MultiLevelTemplateArgumentList &TemplateArgs) {
2422  assert(Proto->getExceptionSpecType() != EST_Uninstantiated);
2423
2424  // C++11 [expr.prim.general]p3:
2425  //   If a declaration declares a member function or member function
2426  //   template of a class X, the expression this is a prvalue of type
2427  //   "pointer to cv-qualifier-seq X" between the optional cv-qualifer-seq
2428  //   and the end of the function-definition, member-declarator, or
2429  //   declarator.
2430  CXXRecordDecl *ThisContext = 0;
2431  unsigned ThisTypeQuals = 0;
2432  if (CXXMethodDecl *Method = dyn_cast<CXXMethodDecl>(New)) {
2433    ThisContext = Method->getParent();
2434    ThisTypeQuals = Method->getTypeQualifiers();
2435  }
2436  Sema::CXXThisScopeRAII ThisScope(SemaRef, ThisContext, ThisTypeQuals,
2437                                   SemaRef.getLangOpts().CPlusPlus0x);
2438
2439  // The function has an exception specification or a "noreturn"
2440  // attribute. Substitute into each of the exception types.
2441  SmallVector<QualType, 4> Exceptions;
2442  for (unsigned I = 0, N = Proto->getNumExceptions(); I != N; ++I) {
2443    // FIXME: Poor location information!
2444    if (const PackExpansionType *PackExpansion
2445          = Proto->getExceptionType(I)->getAs<PackExpansionType>()) {
2446      // We have a pack expansion. Instantiate it.
2447      SmallVector<UnexpandedParameterPack, 2> Unexpanded;
2448      SemaRef.collectUnexpandedParameterPacks(PackExpansion->getPattern(),
2449                                              Unexpanded);
2450      assert(!Unexpanded.empty() &&
2451             "Pack expansion without parameter packs?");
2452
2453      bool Expand = false;
2454      bool RetainExpansion = false;
2455      llvm::Optional<unsigned> NumExpansions
2456                                        = PackExpansion->getNumExpansions();
2457      if (SemaRef.CheckParameterPacksForExpansion(New->getLocation(),
2458                                                  SourceRange(),
2459                                                  Unexpanded,
2460                                                  TemplateArgs,
2461                                                  Expand,
2462                                                  RetainExpansion,
2463                                                  NumExpansions))
2464        break;
2465
2466      if (!Expand) {
2467        // We can't expand this pack expansion into separate arguments yet;
2468        // just substitute into the pattern and create a new pack expansion
2469        // type.
2470        Sema::ArgumentPackSubstitutionIndexRAII SubstIndex(SemaRef, -1);
2471        QualType T = SemaRef.SubstType(PackExpansion->getPattern(),
2472                                       TemplateArgs,
2473                                     New->getLocation(), New->getDeclName());
2474        if (T.isNull())
2475          break;
2476
2477        T = SemaRef.Context.getPackExpansionType(T, NumExpansions);
2478        Exceptions.push_back(T);
2479        continue;
2480      }
2481
2482      // Substitute into the pack expansion pattern for each template
2483      bool Invalid = false;
2484      for (unsigned ArgIdx = 0; ArgIdx != *NumExpansions; ++ArgIdx) {
2485        Sema::ArgumentPackSubstitutionIndexRAII SubstIndex(SemaRef, ArgIdx);
2486
2487        QualType T = SemaRef.SubstType(PackExpansion->getPattern(),
2488                                       TemplateArgs,
2489                                     New->getLocation(), New->getDeclName());
2490        if (T.isNull()) {
2491          Invalid = true;
2492          break;
2493        }
2494
2495        Exceptions.push_back(T);
2496      }
2497
2498      if (Invalid)
2499        break;
2500
2501      continue;
2502    }
2503
2504    QualType T
2505      = SemaRef.SubstType(Proto->getExceptionType(I), TemplateArgs,
2506                          New->getLocation(), New->getDeclName());
2507    if (T.isNull() ||
2508        SemaRef.CheckSpecifiedExceptionType(T, New->getLocation()))
2509      continue;
2510
2511    Exceptions.push_back(T);
2512  }
2513  Expr *NoexceptExpr = 0;
2514  if (Expr *OldNoexceptExpr = Proto->getNoexceptExpr()) {
2515    EnterExpressionEvaluationContext Unevaluated(SemaRef,
2516                                                 Sema::ConstantEvaluated);
2517    ExprResult E = SemaRef.SubstExpr(OldNoexceptExpr, TemplateArgs);
2518    if (E.isUsable())
2519      E = SemaRef.CheckBooleanCondition(E.get(), E.get()->getLocStart());
2520
2521    if (E.isUsable()) {
2522      NoexceptExpr = E.take();
2523      if (!NoexceptExpr->isTypeDependent() &&
2524          !NoexceptExpr->isValueDependent())
2525        NoexceptExpr
2526          = SemaRef.VerifyIntegerConstantExpression(NoexceptExpr,
2527              0, diag::err_noexcept_needs_constant_expression,
2528              /*AllowFold*/ false).take();
2529    }
2530  }
2531
2532  // Rebuild the function type
2533  const FunctionProtoType *NewProto
2534    = New->getType()->getAs<FunctionProtoType>();
2535  assert(NewProto && "Template instantiation without function prototype?");
2536
2537  FunctionProtoType::ExtProtoInfo EPI = NewProto->getExtProtoInfo();
2538  EPI.ExceptionSpecType = Proto->getExceptionSpecType();
2539  EPI.NumExceptions = Exceptions.size();
2540  EPI.Exceptions = Exceptions.data();
2541  EPI.NoexceptExpr = NoexceptExpr;
2542
2543  New->setType(SemaRef.Context.getFunctionType(NewProto->getResultType(),
2544                                               NewProto->arg_type_begin(),
2545                                               NewProto->getNumArgs(),
2546                                               EPI));
2547}
2548
2549void Sema::InstantiateExceptionSpec(SourceLocation PointOfInstantiation,
2550                                    FunctionDecl *Decl) {
2551  const FunctionProtoType *Proto = Decl->getType()->castAs<FunctionProtoType>();
2552  if (Proto->getExceptionSpecType() != EST_Uninstantiated)
2553    return;
2554
2555  InstantiatingTemplate Inst(*this, PointOfInstantiation, Decl,
2556                             InstantiatingTemplate::ExceptionSpecification());
2557  if (Inst) {
2558    // We hit the instantiation depth limit. Clear the exception specification
2559    // so that our callers don't have to cope with EST_Uninstantiated.
2560    FunctionProtoType::ExtProtoInfo EPI = Proto->getExtProtoInfo();
2561    EPI.ExceptionSpecType = EST_None;
2562    Decl->setType(Context.getFunctionType(Proto->getResultType(),
2563                                          Proto->arg_type_begin(),
2564                                          Proto->getNumArgs(),
2565                                          EPI));
2566    return;
2567  }
2568
2569  // Enter the scope of this instantiation. We don't use
2570  // PushDeclContext because we don't have a scope.
2571  Sema::ContextRAII savedContext(*this, Decl);
2572  LocalInstantiationScope Scope(*this);
2573
2574  MultiLevelTemplateArgumentList TemplateArgs =
2575    getTemplateInstantiationArgs(Decl, 0, /*RelativeToPrimary*/true);
2576
2577  FunctionDecl *Template = Proto->getExceptionSpecTemplate();
2578  addInstantiatedParametersToScope(*this, Decl, Template, Scope, TemplateArgs);
2579
2580  ::InstantiateExceptionSpec(*this, Decl,
2581                             Template->getType()->castAs<FunctionProtoType>(),
2582                             TemplateArgs);
2583}
2584
2585/// \brief Initializes the common fields of an instantiation function
2586/// declaration (New) from the corresponding fields of its template (Tmpl).
2587///
2588/// \returns true if there was an error
2589bool
2590TemplateDeclInstantiator::InitFunctionInstantiation(FunctionDecl *New,
2591                                                    FunctionDecl *Tmpl) {
2592  if (Tmpl->isDeleted())
2593    New->setDeletedAsWritten();
2594
2595  // If we are performing substituting explicitly-specified template arguments
2596  // or deduced template arguments into a function template and we reach this
2597  // point, we are now past the point where SFINAE applies and have committed
2598  // to keeping the new function template specialization. We therefore
2599  // convert the active template instantiation for the function template
2600  // into a template instantiation for this specific function template
2601  // specialization, which is not a SFINAE context, so that we diagnose any
2602  // further errors in the declaration itself.
2603  typedef Sema::ActiveTemplateInstantiation ActiveInstType;
2604  ActiveInstType &ActiveInst = SemaRef.ActiveTemplateInstantiations.back();
2605  if (ActiveInst.Kind == ActiveInstType::ExplicitTemplateArgumentSubstitution ||
2606      ActiveInst.Kind == ActiveInstType::DeducedTemplateArgumentSubstitution) {
2607    if (FunctionTemplateDecl *FunTmpl
2608          = dyn_cast<FunctionTemplateDecl>((Decl *)ActiveInst.Entity)) {
2609      assert(FunTmpl->getTemplatedDecl() == Tmpl &&
2610             "Deduction from the wrong function template?");
2611      (void) FunTmpl;
2612      ActiveInst.Kind = ActiveInstType::TemplateInstantiation;
2613      ActiveInst.Entity = reinterpret_cast<uintptr_t>(New);
2614    }
2615  }
2616
2617  const FunctionProtoType *Proto = Tmpl->getType()->getAs<FunctionProtoType>();
2618  assert(Proto && "Function template without prototype?");
2619
2620  if (Proto->hasExceptionSpec() || Proto->getNoReturnAttr()) {
2621    FunctionProtoType::ExtProtoInfo EPI = Proto->getExtProtoInfo();
2622
2623    // DR1330: In C++11, defer instantiation of a non-trivial
2624    // exception specification.
2625    if (SemaRef.getLangOpts().CPlusPlus0x &&
2626        EPI.ExceptionSpecType != EST_None &&
2627        EPI.ExceptionSpecType != EST_DynamicNone &&
2628        EPI.ExceptionSpecType != EST_BasicNoexcept) {
2629      FunctionDecl *ExceptionSpecTemplate = Tmpl;
2630      if (EPI.ExceptionSpecType == EST_Uninstantiated)
2631        ExceptionSpecTemplate = EPI.ExceptionSpecTemplate;
2632      assert(EPI.ExceptionSpecType != EST_Unevaluated &&
2633             "instantiating implicitly-declared special member");
2634
2635      // Mark the function has having an uninstantiated exception specification.
2636      const FunctionProtoType *NewProto
2637        = New->getType()->getAs<FunctionProtoType>();
2638      assert(NewProto && "Template instantiation without function prototype?");
2639      EPI = NewProto->getExtProtoInfo();
2640      EPI.ExceptionSpecType = EST_Uninstantiated;
2641      EPI.ExceptionSpecDecl = New;
2642      EPI.ExceptionSpecTemplate = ExceptionSpecTemplate;
2643      New->setType(SemaRef.Context.getFunctionType(NewProto->getResultType(),
2644                                                   NewProto->arg_type_begin(),
2645                                                   NewProto->getNumArgs(),
2646                                                   EPI));
2647    } else {
2648      ::InstantiateExceptionSpec(SemaRef, New, Proto, TemplateArgs);
2649    }
2650  }
2651
2652  // Get the definition. Leaves the variable unchanged if undefined.
2653  const FunctionDecl *Definition = Tmpl;
2654  Tmpl->isDefined(Definition);
2655
2656  SemaRef.InstantiateAttrs(TemplateArgs, Definition, New,
2657                           LateAttrs, StartingScope);
2658
2659  return false;
2660}
2661
2662/// \brief Initializes common fields of an instantiated method
2663/// declaration (New) from the corresponding fields of its template
2664/// (Tmpl).
2665///
2666/// \returns true if there was an error
2667bool
2668TemplateDeclInstantiator::InitMethodInstantiation(CXXMethodDecl *New,
2669                                                  CXXMethodDecl *Tmpl) {
2670  if (InitFunctionInstantiation(New, Tmpl))
2671    return true;
2672
2673  New->setAccess(Tmpl->getAccess());
2674  if (Tmpl->isVirtualAsWritten())
2675    New->setVirtualAsWritten(true);
2676
2677  // FIXME: attributes
2678  // FIXME: New needs a pointer to Tmpl
2679  return false;
2680}
2681
2682/// \brief Instantiate the definition of the given function from its
2683/// template.
2684///
2685/// \param PointOfInstantiation the point at which the instantiation was
2686/// required. Note that this is not precisely a "point of instantiation"
2687/// for the function, but it's close.
2688///
2689/// \param Function the already-instantiated declaration of a
2690/// function template specialization or member function of a class template
2691/// specialization.
2692///
2693/// \param Recursive if true, recursively instantiates any functions that
2694/// are required by this instantiation.
2695///
2696/// \param DefinitionRequired if true, then we are performing an explicit
2697/// instantiation where the body of the function is required. Complain if
2698/// there is no such body.
2699void Sema::InstantiateFunctionDefinition(SourceLocation PointOfInstantiation,
2700                                         FunctionDecl *Function,
2701                                         bool Recursive,
2702                                         bool DefinitionRequired) {
2703  if (Function->isInvalidDecl() || Function->isDefined())
2704    return;
2705
2706  // Never instantiate an explicit specialization except if it is a class scope
2707  // explicit specialization.
2708  if (Function->getTemplateSpecializationKind() == TSK_ExplicitSpecialization &&
2709      !Function->getClassScopeSpecializationPattern())
2710    return;
2711
2712  // Find the function body that we'll be substituting.
2713  const FunctionDecl *PatternDecl = Function->getTemplateInstantiationPattern();
2714  assert(PatternDecl && "instantiating a non-template");
2715
2716  Stmt *Pattern = PatternDecl->getBody(PatternDecl);
2717  assert(PatternDecl && "template definition is not a template");
2718  if (!Pattern) {
2719    // Try to find a defaulted definition
2720    PatternDecl->isDefined(PatternDecl);
2721  }
2722  assert(PatternDecl && "template definition is not a template");
2723
2724  // Postpone late parsed template instantiations.
2725  if (PatternDecl->isLateTemplateParsed() &&
2726      !LateTemplateParser) {
2727    PendingInstantiations.push_back(
2728      std::make_pair(Function, PointOfInstantiation));
2729    return;
2730  }
2731
2732  // Call the LateTemplateParser callback if there a need to late parse
2733  // a templated function definition.
2734  if (!Pattern && PatternDecl->isLateTemplateParsed() &&
2735      LateTemplateParser) {
2736    LateTemplateParser(OpaqueParser, PatternDecl);
2737    Pattern = PatternDecl->getBody(PatternDecl);
2738  }
2739
2740  if (!Pattern && !PatternDecl->isDefaulted()) {
2741    if (DefinitionRequired) {
2742      if (Function->getPrimaryTemplate())
2743        Diag(PointOfInstantiation,
2744             diag::err_explicit_instantiation_undefined_func_template)
2745          << Function->getPrimaryTemplate();
2746      else
2747        Diag(PointOfInstantiation,
2748             diag::err_explicit_instantiation_undefined_member)
2749          << 1 << Function->getDeclName() << Function->getDeclContext();
2750
2751      if (PatternDecl)
2752        Diag(PatternDecl->getLocation(),
2753             diag::note_explicit_instantiation_here);
2754      Function->setInvalidDecl();
2755    } else if (Function->getTemplateSpecializationKind()
2756                 == TSK_ExplicitInstantiationDefinition) {
2757      PendingInstantiations.push_back(
2758        std::make_pair(Function, PointOfInstantiation));
2759    }
2760
2761    return;
2762  }
2763
2764  // C++0x [temp.explicit]p9:
2765  //   Except for inline functions, other explicit instantiation declarations
2766  //   have the effect of suppressing the implicit instantiation of the entity
2767  //   to which they refer.
2768  if (Function->getTemplateSpecializationKind()
2769        == TSK_ExplicitInstantiationDeclaration &&
2770      !PatternDecl->isInlined())
2771    return;
2772
2773  InstantiatingTemplate Inst(*this, PointOfInstantiation, Function);
2774  if (Inst)
2775    return;
2776
2777  // Copy the inner loc start from the pattern.
2778  Function->setInnerLocStart(PatternDecl->getInnerLocStart());
2779
2780  // If we're performing recursive template instantiation, create our own
2781  // queue of pending implicit instantiations that we will instantiate later,
2782  // while we're still within our own instantiation context.
2783  SmallVector<VTableUse, 16> SavedVTableUses;
2784  std::deque<PendingImplicitInstantiation> SavedPendingInstantiations;
2785  if (Recursive) {
2786    VTableUses.swap(SavedVTableUses);
2787    PendingInstantiations.swap(SavedPendingInstantiations);
2788  }
2789
2790  EnterExpressionEvaluationContext EvalContext(*this,
2791                                               Sema::PotentiallyEvaluated);
2792  ActOnStartOfFunctionDef(0, Function);
2793
2794  // Introduce a new scope where local variable instantiations will be
2795  // recorded, unless we're actually a member function within a local
2796  // class, in which case we need to merge our results with the parent
2797  // scope (of the enclosing function).
2798  bool MergeWithParentScope = false;
2799  if (CXXRecordDecl *Rec = dyn_cast<CXXRecordDecl>(Function->getDeclContext()))
2800    MergeWithParentScope = Rec->isLocalClass();
2801
2802  LocalInstantiationScope Scope(*this, MergeWithParentScope);
2803
2804  // Enter the scope of this instantiation. We don't use
2805  // PushDeclContext because we don't have a scope.
2806  Sema::ContextRAII savedContext(*this, Function);
2807
2808  MultiLevelTemplateArgumentList TemplateArgs =
2809    getTemplateInstantiationArgs(Function, 0, false, PatternDecl);
2810
2811  addInstantiatedParametersToScope(*this, Function, PatternDecl, Scope,
2812                                   TemplateArgs);
2813
2814  if (PatternDecl->isDefaulted()) {
2815    ActOnFinishFunctionBody(Function, 0, /*IsInstantiation=*/true);
2816
2817    SetDeclDefaulted(Function, PatternDecl->getLocation());
2818  } else {
2819    // If this is a constructor, instantiate the member initializers.
2820    if (const CXXConstructorDecl *Ctor =
2821          dyn_cast<CXXConstructorDecl>(PatternDecl)) {
2822      InstantiateMemInitializers(cast<CXXConstructorDecl>(Function), Ctor,
2823                                 TemplateArgs);
2824    }
2825
2826    // Instantiate the function body.
2827    StmtResult Body = SubstStmt(Pattern, TemplateArgs);
2828
2829    if (Body.isInvalid())
2830      Function->setInvalidDecl();
2831
2832    ActOnFinishFunctionBody(Function, Body.get(),
2833                            /*IsInstantiation=*/true);
2834  }
2835
2836  PerformDependentDiagnostics(PatternDecl, TemplateArgs);
2837
2838  savedContext.pop();
2839
2840  DeclGroupRef DG(Function);
2841  Consumer.HandleTopLevelDecl(DG);
2842
2843  // This class may have local implicit instantiations that need to be
2844  // instantiation within this scope.
2845  PerformPendingInstantiations(/*LocalOnly=*/true);
2846  Scope.Exit();
2847
2848  if (Recursive) {
2849    // Define any pending vtables.
2850    DefineUsedVTables();
2851
2852    // Instantiate any pending implicit instantiations found during the
2853    // instantiation of this template.
2854    PerformPendingInstantiations();
2855
2856    // Restore the set of pending vtables.
2857    assert(VTableUses.empty() &&
2858           "VTableUses should be empty before it is discarded.");
2859    VTableUses.swap(SavedVTableUses);
2860
2861    // Restore the set of pending implicit instantiations.
2862    assert(PendingInstantiations.empty() &&
2863           "PendingInstantiations should be empty before it is discarded.");
2864    PendingInstantiations.swap(SavedPendingInstantiations);
2865  }
2866}
2867
2868/// \brief Instantiate the definition of the given variable from its
2869/// template.
2870///
2871/// \param PointOfInstantiation the point at which the instantiation was
2872/// required. Note that this is not precisely a "point of instantiation"
2873/// for the function, but it's close.
2874///
2875/// \param Var the already-instantiated declaration of a static member
2876/// variable of a class template specialization.
2877///
2878/// \param Recursive if true, recursively instantiates any functions that
2879/// are required by this instantiation.
2880///
2881/// \param DefinitionRequired if true, then we are performing an explicit
2882/// instantiation where an out-of-line definition of the member variable
2883/// is required. Complain if there is no such definition.
2884void Sema::InstantiateStaticDataMemberDefinition(
2885                                          SourceLocation PointOfInstantiation,
2886                                                 VarDecl *Var,
2887                                                 bool Recursive,
2888                                                 bool DefinitionRequired) {
2889  if (Var->isInvalidDecl())
2890    return;
2891
2892  // Find the out-of-line definition of this static data member.
2893  VarDecl *Def = Var->getInstantiatedFromStaticDataMember();
2894  assert(Def && "This data member was not instantiated from a template?");
2895  assert(Def->isStaticDataMember() && "Not a static data member?");
2896  Def = Def->getOutOfLineDefinition();
2897
2898  if (!Def) {
2899    // We did not find an out-of-line definition of this static data member,
2900    // so we won't perform any instantiation. Rather, we rely on the user to
2901    // instantiate this definition (or provide a specialization for it) in
2902    // another translation unit.
2903    if (DefinitionRequired) {
2904      Def = Var->getInstantiatedFromStaticDataMember();
2905      Diag(PointOfInstantiation,
2906           diag::err_explicit_instantiation_undefined_member)
2907        << 2 << Var->getDeclName() << Var->getDeclContext();
2908      Diag(Def->getLocation(), diag::note_explicit_instantiation_here);
2909    } else if (Var->getTemplateSpecializationKind()
2910                 == TSK_ExplicitInstantiationDefinition) {
2911      PendingInstantiations.push_back(
2912        std::make_pair(Var, PointOfInstantiation));
2913    }
2914
2915    return;
2916  }
2917
2918  TemplateSpecializationKind TSK = Var->getTemplateSpecializationKind();
2919
2920  // Never instantiate an explicit specialization.
2921  if (TSK == TSK_ExplicitSpecialization)
2922    return;
2923
2924  // C++0x [temp.explicit]p9:
2925  //   Except for inline functions, other explicit instantiation declarations
2926  //   have the effect of suppressing the implicit instantiation of the entity
2927  //   to which they refer.
2928  if (TSK == TSK_ExplicitInstantiationDeclaration)
2929    return;
2930
2931  Consumer.HandleCXXStaticMemberVarInstantiation(Var);
2932
2933  // If we already have a definition, we're done.
2934  if (VarDecl *Def = Var->getDefinition()) {
2935    // We may be explicitly instantiating something we've already implicitly
2936    // instantiated.
2937    Def->setTemplateSpecializationKind(Var->getTemplateSpecializationKind(),
2938                                       PointOfInstantiation);
2939    return;
2940  }
2941
2942  InstantiatingTemplate Inst(*this, PointOfInstantiation, Var);
2943  if (Inst)
2944    return;
2945
2946  // If we're performing recursive template instantiation, create our own
2947  // queue of pending implicit instantiations that we will instantiate later,
2948  // while we're still within our own instantiation context.
2949  SmallVector<VTableUse, 16> SavedVTableUses;
2950  std::deque<PendingImplicitInstantiation> SavedPendingInstantiations;
2951  if (Recursive) {
2952    VTableUses.swap(SavedVTableUses);
2953    PendingInstantiations.swap(SavedPendingInstantiations);
2954  }
2955
2956  // Enter the scope of this instantiation. We don't use
2957  // PushDeclContext because we don't have a scope.
2958  ContextRAII previousContext(*this, Var->getDeclContext());
2959  LocalInstantiationScope Local(*this);
2960
2961  VarDecl *OldVar = Var;
2962  Var = cast_or_null<VarDecl>(SubstDecl(Def, Var->getDeclContext(),
2963                                        getTemplateInstantiationArgs(Var)));
2964
2965  previousContext.pop();
2966
2967  if (Var) {
2968    MemberSpecializationInfo *MSInfo = OldVar->getMemberSpecializationInfo();
2969    assert(MSInfo && "Missing member specialization information?");
2970    Var->setTemplateSpecializationKind(MSInfo->getTemplateSpecializationKind(),
2971                                       MSInfo->getPointOfInstantiation());
2972    DeclGroupRef DG(Var);
2973    Consumer.HandleTopLevelDecl(DG);
2974  }
2975  Local.Exit();
2976
2977  if (Recursive) {
2978    // Define any newly required vtables.
2979    DefineUsedVTables();
2980
2981    // Instantiate any pending implicit instantiations found during the
2982    // instantiation of this template.
2983    PerformPendingInstantiations();
2984
2985    // Restore the set of pending vtables.
2986    assert(VTableUses.empty() &&
2987           "VTableUses should be empty before it is discarded, "
2988           "while instantiating static data member.");
2989    VTableUses.swap(SavedVTableUses);
2990
2991    // Restore the set of pending implicit instantiations.
2992    assert(PendingInstantiations.empty() &&
2993           "PendingInstantiations should be empty before it is discarded, "
2994           "while instantiating static data member.");
2995    PendingInstantiations.swap(SavedPendingInstantiations);
2996  }
2997}
2998
2999void
3000Sema::InstantiateMemInitializers(CXXConstructorDecl *New,
3001                                 const CXXConstructorDecl *Tmpl,
3002                           const MultiLevelTemplateArgumentList &TemplateArgs) {
3003
3004  SmallVector<CXXCtorInitializer*, 4> NewInits;
3005  bool AnyErrors = Tmpl->isInvalidDecl();
3006
3007  // Instantiate all the initializers.
3008  for (CXXConstructorDecl::init_const_iterator Inits = Tmpl->init_begin(),
3009                                            InitsEnd = Tmpl->init_end();
3010       Inits != InitsEnd; ++Inits) {
3011    CXXCtorInitializer *Init = *Inits;
3012
3013    // Only instantiate written initializers, let Sema re-construct implicit
3014    // ones.
3015    if (!Init->isWritten())
3016      continue;
3017
3018    SourceLocation EllipsisLoc;
3019
3020    if (Init->isPackExpansion()) {
3021      // This is a pack expansion. We should expand it now.
3022      TypeLoc BaseTL = Init->getTypeSourceInfo()->getTypeLoc();
3023      SmallVector<UnexpandedParameterPack, 2> Unexpanded;
3024      collectUnexpandedParameterPacks(BaseTL, Unexpanded);
3025      bool ShouldExpand = false;
3026      bool RetainExpansion = false;
3027      llvm::Optional<unsigned> NumExpansions;
3028      if (CheckParameterPacksForExpansion(Init->getEllipsisLoc(),
3029                                          BaseTL.getSourceRange(),
3030                                          Unexpanded,
3031                                          TemplateArgs, ShouldExpand,
3032                                          RetainExpansion,
3033                                          NumExpansions)) {
3034        AnyErrors = true;
3035        New->setInvalidDecl();
3036        continue;
3037      }
3038      assert(ShouldExpand && "Partial instantiation of base initializer?");
3039
3040      // Loop over all of the arguments in the argument pack(s),
3041      for (unsigned I = 0; I != *NumExpansions; ++I) {
3042        Sema::ArgumentPackSubstitutionIndexRAII SubstIndex(*this, I);
3043
3044        // Instantiate the initializer.
3045        ExprResult TempInit = SubstInitializer(Init->getInit(), TemplateArgs,
3046                                               /*CXXDirectInit=*/true);
3047        if (TempInit.isInvalid()) {
3048          AnyErrors = true;
3049          break;
3050        }
3051
3052        // Instantiate the base type.
3053        TypeSourceInfo *BaseTInfo = SubstType(Init->getTypeSourceInfo(),
3054                                              TemplateArgs,
3055                                              Init->getSourceLocation(),
3056                                              New->getDeclName());
3057        if (!BaseTInfo) {
3058          AnyErrors = true;
3059          break;
3060        }
3061
3062        // Build the initializer.
3063        MemInitResult NewInit = BuildBaseInitializer(BaseTInfo->getType(),
3064                                                     BaseTInfo, TempInit.take(),
3065                                                     New->getParent(),
3066                                                     SourceLocation());
3067        if (NewInit.isInvalid()) {
3068          AnyErrors = true;
3069          break;
3070        }
3071
3072        NewInits.push_back(NewInit.get());
3073      }
3074
3075      continue;
3076    }
3077
3078    // Instantiate the initializer.
3079    ExprResult TempInit = SubstInitializer(Init->getInit(), TemplateArgs,
3080                                           /*CXXDirectInit=*/true);
3081    if (TempInit.isInvalid()) {
3082      AnyErrors = true;
3083      continue;
3084    }
3085
3086    MemInitResult NewInit;
3087    if (Init->isDelegatingInitializer() || Init->isBaseInitializer()) {
3088      TypeSourceInfo *TInfo = SubstType(Init->getTypeSourceInfo(),
3089                                        TemplateArgs,
3090                                        Init->getSourceLocation(),
3091                                        New->getDeclName());
3092      if (!TInfo) {
3093        AnyErrors = true;
3094        New->setInvalidDecl();
3095        continue;
3096      }
3097
3098      if (Init->isBaseInitializer())
3099        NewInit = BuildBaseInitializer(TInfo->getType(), TInfo, TempInit.take(),
3100                                       New->getParent(), EllipsisLoc);
3101      else
3102        NewInit = BuildDelegatingInitializer(TInfo, TempInit.take(),
3103                                  cast<CXXRecordDecl>(CurContext->getParent()));
3104    } else if (Init->isMemberInitializer()) {
3105      FieldDecl *Member = cast_or_null<FieldDecl>(FindInstantiatedDecl(
3106                                                     Init->getMemberLocation(),
3107                                                     Init->getMember(),
3108                                                     TemplateArgs));
3109      if (!Member) {
3110        AnyErrors = true;
3111        New->setInvalidDecl();
3112        continue;
3113      }
3114
3115      NewInit = BuildMemberInitializer(Member, TempInit.take(),
3116                                       Init->getSourceLocation());
3117    } else if (Init->isIndirectMemberInitializer()) {
3118      IndirectFieldDecl *IndirectMember =
3119         cast_or_null<IndirectFieldDecl>(FindInstantiatedDecl(
3120                                 Init->getMemberLocation(),
3121                                 Init->getIndirectMember(), TemplateArgs));
3122
3123      if (!IndirectMember) {
3124        AnyErrors = true;
3125        New->setInvalidDecl();
3126        continue;
3127      }
3128
3129      NewInit = BuildMemberInitializer(IndirectMember, TempInit.take(),
3130                                       Init->getSourceLocation());
3131    }
3132
3133    if (NewInit.isInvalid()) {
3134      AnyErrors = true;
3135      New->setInvalidDecl();
3136    } else {
3137      NewInits.push_back(NewInit.get());
3138    }
3139  }
3140
3141  // Assign all the initializers to the new constructor.
3142  ActOnMemInitializers(New,
3143                       /*FIXME: ColonLoc */
3144                       SourceLocation(),
3145                       NewInits.data(), NewInits.size(),
3146                       AnyErrors);
3147}
3148
3149ExprResult Sema::SubstInitializer(Expr *Init,
3150                          const MultiLevelTemplateArgumentList &TemplateArgs,
3151                          bool CXXDirectInit) {
3152  // Initializers are instantiated like expressions, except that various outer
3153  // layers are stripped.
3154  if (!Init)
3155    return Owned(Init);
3156
3157  if (ExprWithCleanups *ExprTemp = dyn_cast<ExprWithCleanups>(Init))
3158    Init = ExprTemp->getSubExpr();
3159
3160  while (CXXBindTemporaryExpr *Binder = dyn_cast<CXXBindTemporaryExpr>(Init))
3161    Init = Binder->getSubExpr();
3162
3163  if (ImplicitCastExpr *ICE = dyn_cast<ImplicitCastExpr>(Init))
3164    Init = ICE->getSubExprAsWritten();
3165
3166  // If this is a direct-initializer, we take apart CXXConstructExprs.
3167  // Everything else is passed through.
3168  CXXConstructExpr *Construct;
3169  if (!CXXDirectInit || !(Construct = dyn_cast<CXXConstructExpr>(Init)) ||
3170      isa<CXXTemporaryObjectExpr>(Construct))
3171    return SubstExpr(Init, TemplateArgs);
3172
3173  SmallVector<Expr*, 8> NewArgs;
3174  if (SubstExprs(Construct->getArgs(), Construct->getNumArgs(), true,
3175                 TemplateArgs, NewArgs))
3176    return ExprError();
3177
3178  // Treat an empty initializer like none.
3179  if (NewArgs.empty())
3180    return Owned((Expr*)0);
3181
3182  // Build a ParenListExpr to represent anything else.
3183  // FIXME: Fake locations!
3184  SourceLocation Loc = PP.getLocForEndOfToken(Init->getLocStart());
3185  return ActOnParenListExpr(Loc, Loc, NewArgs);
3186}
3187
3188// TODO: this could be templated if the various decl types used the
3189// same method name.
3190static bool isInstantiationOf(ClassTemplateDecl *Pattern,
3191                              ClassTemplateDecl *Instance) {
3192  Pattern = Pattern->getCanonicalDecl();
3193
3194  do {
3195    Instance = Instance->getCanonicalDecl();
3196    if (Pattern == Instance) return true;
3197    Instance = Instance->getInstantiatedFromMemberTemplate();
3198  } while (Instance);
3199
3200  return false;
3201}
3202
3203static bool isInstantiationOf(FunctionTemplateDecl *Pattern,
3204                              FunctionTemplateDecl *Instance) {
3205  Pattern = Pattern->getCanonicalDecl();
3206
3207  do {
3208    Instance = Instance->getCanonicalDecl();
3209    if (Pattern == Instance) return true;
3210    Instance = Instance->getInstantiatedFromMemberTemplate();
3211  } while (Instance);
3212
3213  return false;
3214}
3215
3216static bool
3217isInstantiationOf(ClassTemplatePartialSpecializationDecl *Pattern,
3218                  ClassTemplatePartialSpecializationDecl *Instance) {
3219  Pattern
3220    = cast<ClassTemplatePartialSpecializationDecl>(Pattern->getCanonicalDecl());
3221  do {
3222    Instance = cast<ClassTemplatePartialSpecializationDecl>(
3223                                                Instance->getCanonicalDecl());
3224    if (Pattern == Instance)
3225      return true;
3226    Instance = Instance->getInstantiatedFromMember();
3227  } while (Instance);
3228
3229  return false;
3230}
3231
3232static bool isInstantiationOf(CXXRecordDecl *Pattern,
3233                              CXXRecordDecl *Instance) {
3234  Pattern = Pattern->getCanonicalDecl();
3235
3236  do {
3237    Instance = Instance->getCanonicalDecl();
3238    if (Pattern == Instance) return true;
3239    Instance = Instance->getInstantiatedFromMemberClass();
3240  } while (Instance);
3241
3242  return false;
3243}
3244
3245static bool isInstantiationOf(FunctionDecl *Pattern,
3246                              FunctionDecl *Instance) {
3247  Pattern = Pattern->getCanonicalDecl();
3248
3249  do {
3250    Instance = Instance->getCanonicalDecl();
3251    if (Pattern == Instance) return true;
3252    Instance = Instance->getInstantiatedFromMemberFunction();
3253  } while (Instance);
3254
3255  return false;
3256}
3257
3258static bool isInstantiationOf(EnumDecl *Pattern,
3259                              EnumDecl *Instance) {
3260  Pattern = Pattern->getCanonicalDecl();
3261
3262  do {
3263    Instance = Instance->getCanonicalDecl();
3264    if (Pattern == Instance) return true;
3265    Instance = Instance->getInstantiatedFromMemberEnum();
3266  } while (Instance);
3267
3268  return false;
3269}
3270
3271static bool isInstantiationOf(UsingShadowDecl *Pattern,
3272                              UsingShadowDecl *Instance,
3273                              ASTContext &C) {
3274  return C.getInstantiatedFromUsingShadowDecl(Instance) == Pattern;
3275}
3276
3277static bool isInstantiationOf(UsingDecl *Pattern,
3278                              UsingDecl *Instance,
3279                              ASTContext &C) {
3280  return C.getInstantiatedFromUsingDecl(Instance) == Pattern;
3281}
3282
3283static bool isInstantiationOf(UnresolvedUsingValueDecl *Pattern,
3284                              UsingDecl *Instance,
3285                              ASTContext &C) {
3286  return C.getInstantiatedFromUsingDecl(Instance) == Pattern;
3287}
3288
3289static bool isInstantiationOf(UnresolvedUsingTypenameDecl *Pattern,
3290                              UsingDecl *Instance,
3291                              ASTContext &C) {
3292  return C.getInstantiatedFromUsingDecl(Instance) == Pattern;
3293}
3294
3295static bool isInstantiationOfStaticDataMember(VarDecl *Pattern,
3296                                              VarDecl *Instance) {
3297  assert(Instance->isStaticDataMember());
3298
3299  Pattern = Pattern->getCanonicalDecl();
3300
3301  do {
3302    Instance = Instance->getCanonicalDecl();
3303    if (Pattern == Instance) return true;
3304    Instance = Instance->getInstantiatedFromStaticDataMember();
3305  } while (Instance);
3306
3307  return false;
3308}
3309
3310// Other is the prospective instantiation
3311// D is the prospective pattern
3312static bool isInstantiationOf(ASTContext &Ctx, NamedDecl *D, Decl *Other) {
3313  if (D->getKind() != Other->getKind()) {
3314    if (UnresolvedUsingTypenameDecl *UUD
3315          = dyn_cast<UnresolvedUsingTypenameDecl>(D)) {
3316      if (UsingDecl *UD = dyn_cast<UsingDecl>(Other)) {
3317        return isInstantiationOf(UUD, UD, Ctx);
3318      }
3319    }
3320
3321    if (UnresolvedUsingValueDecl *UUD
3322          = dyn_cast<UnresolvedUsingValueDecl>(D)) {
3323      if (UsingDecl *UD = dyn_cast<UsingDecl>(Other)) {
3324        return isInstantiationOf(UUD, UD, Ctx);
3325      }
3326    }
3327
3328    return false;
3329  }
3330
3331  if (CXXRecordDecl *Record = dyn_cast<CXXRecordDecl>(Other))
3332    return isInstantiationOf(cast<CXXRecordDecl>(D), Record);
3333
3334  if (FunctionDecl *Function = dyn_cast<FunctionDecl>(Other))
3335    return isInstantiationOf(cast<FunctionDecl>(D), Function);
3336
3337  if (EnumDecl *Enum = dyn_cast<EnumDecl>(Other))
3338    return isInstantiationOf(cast<EnumDecl>(D), Enum);
3339
3340  if (VarDecl *Var = dyn_cast<VarDecl>(Other))
3341    if (Var->isStaticDataMember())
3342      return isInstantiationOfStaticDataMember(cast<VarDecl>(D), Var);
3343
3344  if (ClassTemplateDecl *Temp = dyn_cast<ClassTemplateDecl>(Other))
3345    return isInstantiationOf(cast<ClassTemplateDecl>(D), Temp);
3346
3347  if (FunctionTemplateDecl *Temp = dyn_cast<FunctionTemplateDecl>(Other))
3348    return isInstantiationOf(cast<FunctionTemplateDecl>(D), Temp);
3349
3350  if (ClassTemplatePartialSpecializationDecl *PartialSpec
3351        = dyn_cast<ClassTemplatePartialSpecializationDecl>(Other))
3352    return isInstantiationOf(cast<ClassTemplatePartialSpecializationDecl>(D),
3353                             PartialSpec);
3354
3355  if (FieldDecl *Field = dyn_cast<FieldDecl>(Other)) {
3356    if (!Field->getDeclName()) {
3357      // This is an unnamed field.
3358      return Ctx.getInstantiatedFromUnnamedFieldDecl(Field) ==
3359        cast<FieldDecl>(D);
3360    }
3361  }
3362
3363  if (UsingDecl *Using = dyn_cast<UsingDecl>(Other))
3364    return isInstantiationOf(cast<UsingDecl>(D), Using, Ctx);
3365
3366  if (UsingShadowDecl *Shadow = dyn_cast<UsingShadowDecl>(Other))
3367    return isInstantiationOf(cast<UsingShadowDecl>(D), Shadow, Ctx);
3368
3369  return D->getDeclName() && isa<NamedDecl>(Other) &&
3370    D->getDeclName() == cast<NamedDecl>(Other)->getDeclName();
3371}
3372
3373template<typename ForwardIterator>
3374static NamedDecl *findInstantiationOf(ASTContext &Ctx,
3375                                      NamedDecl *D,
3376                                      ForwardIterator first,
3377                                      ForwardIterator last) {
3378  for (; first != last; ++first)
3379    if (isInstantiationOf(Ctx, D, *first))
3380      return cast<NamedDecl>(*first);
3381
3382  return 0;
3383}
3384
3385/// \brief Finds the instantiation of the given declaration context
3386/// within the current instantiation.
3387///
3388/// \returns NULL if there was an error
3389DeclContext *Sema::FindInstantiatedContext(SourceLocation Loc, DeclContext* DC,
3390                          const MultiLevelTemplateArgumentList &TemplateArgs) {
3391  if (NamedDecl *D = dyn_cast<NamedDecl>(DC)) {
3392    Decl* ID = FindInstantiatedDecl(Loc, D, TemplateArgs);
3393    return cast_or_null<DeclContext>(ID);
3394  } else return DC;
3395}
3396
3397/// \brief Find the instantiation of the given declaration within the
3398/// current instantiation.
3399///
3400/// This routine is intended to be used when \p D is a declaration
3401/// referenced from within a template, that needs to mapped into the
3402/// corresponding declaration within an instantiation. For example,
3403/// given:
3404///
3405/// \code
3406/// template<typename T>
3407/// struct X {
3408///   enum Kind {
3409///     KnownValue = sizeof(T)
3410///   };
3411///
3412///   bool getKind() const { return KnownValue; }
3413/// };
3414///
3415/// template struct X<int>;
3416/// \endcode
3417///
3418/// In the instantiation of X<int>::getKind(), we need to map the
3419/// EnumConstantDecl for KnownValue (which refers to
3420/// X<T>::\<Kind>\::KnownValue) to its instantiation
3421/// (X<int>::\<Kind>\::KnownValue). InstantiateCurrentDeclRef() performs
3422/// this mapping from within the instantiation of X<int>.
3423NamedDecl *Sema::FindInstantiatedDecl(SourceLocation Loc, NamedDecl *D,
3424                          const MultiLevelTemplateArgumentList &TemplateArgs) {
3425  DeclContext *ParentDC = D->getDeclContext();
3426  if (isa<ParmVarDecl>(D) || isa<NonTypeTemplateParmDecl>(D) ||
3427      isa<TemplateTypeParmDecl>(D) || isa<TemplateTemplateParmDecl>(D) ||
3428      (ParentDC->isFunctionOrMethod() && ParentDC->isDependentContext()) ||
3429      (isa<CXXRecordDecl>(D) && cast<CXXRecordDecl>(D)->isLambda())) {
3430    // D is a local of some kind. Look into the map of local
3431    // declarations to their instantiations.
3432    typedef LocalInstantiationScope::DeclArgumentPack DeclArgumentPack;
3433    llvm::PointerUnion<Decl *, DeclArgumentPack *> *Found
3434      = CurrentInstantiationScope->findInstantiationOf(D);
3435
3436    if (Found) {
3437      if (Decl *FD = Found->dyn_cast<Decl *>())
3438        return cast<NamedDecl>(FD);
3439
3440      int PackIdx = ArgumentPackSubstitutionIndex;
3441      assert(PackIdx != -1 && "found declaration pack but not pack expanding");
3442      return cast<NamedDecl>((*Found->get<DeclArgumentPack *>())[PackIdx]);
3443    }
3444
3445    // If we didn't find the decl, then we must have a label decl that hasn't
3446    // been found yet.  Lazily instantiate it and return it now.
3447    assert(isa<LabelDecl>(D));
3448
3449    Decl *Inst = SubstDecl(D, CurContext, TemplateArgs);
3450    assert(Inst && "Failed to instantiate label??");
3451
3452    CurrentInstantiationScope->InstantiatedLocal(D, Inst);
3453    return cast<LabelDecl>(Inst);
3454  }
3455
3456  if (CXXRecordDecl *Record = dyn_cast<CXXRecordDecl>(D)) {
3457    if (!Record->isDependentContext())
3458      return D;
3459
3460    // Determine whether this record is the "templated" declaration describing
3461    // a class template or class template partial specialization.
3462    ClassTemplateDecl *ClassTemplate = Record->getDescribedClassTemplate();
3463    if (ClassTemplate)
3464      ClassTemplate = ClassTemplate->getCanonicalDecl();
3465    else if (ClassTemplatePartialSpecializationDecl *PartialSpec
3466               = dyn_cast<ClassTemplatePartialSpecializationDecl>(Record))
3467      ClassTemplate = PartialSpec->getSpecializedTemplate()->getCanonicalDecl();
3468
3469    // Walk the current context to find either the record or an instantiation of
3470    // it.
3471    DeclContext *DC = CurContext;
3472    while (!DC->isFileContext()) {
3473      // If we're performing substitution while we're inside the template
3474      // definition, we'll find our own context. We're done.
3475      if (DC->Equals(Record))
3476        return Record;
3477
3478      if (CXXRecordDecl *InstRecord = dyn_cast<CXXRecordDecl>(DC)) {
3479        // Check whether we're in the process of instantiating a class template
3480        // specialization of the template we're mapping.
3481        if (ClassTemplateSpecializationDecl *InstSpec
3482                      = dyn_cast<ClassTemplateSpecializationDecl>(InstRecord)){
3483          ClassTemplateDecl *SpecTemplate = InstSpec->getSpecializedTemplate();
3484          if (ClassTemplate && isInstantiationOf(ClassTemplate, SpecTemplate))
3485            return InstRecord;
3486        }
3487
3488        // Check whether we're in the process of instantiating a member class.
3489        if (isInstantiationOf(Record, InstRecord))
3490          return InstRecord;
3491      }
3492
3493
3494      // Move to the outer template scope.
3495      if (FunctionDecl *FD = dyn_cast<FunctionDecl>(DC)) {
3496        if (FD->getFriendObjectKind() && FD->getDeclContext()->isFileContext()){
3497          DC = FD->getLexicalDeclContext();
3498          continue;
3499        }
3500      }
3501
3502      DC = DC->getParent();
3503    }
3504
3505    // Fall through to deal with other dependent record types (e.g.,
3506    // anonymous unions in class templates).
3507  }
3508
3509  if (!ParentDC->isDependentContext())
3510    return D;
3511
3512  ParentDC = FindInstantiatedContext(Loc, ParentDC, TemplateArgs);
3513  if (!ParentDC)
3514    return 0;
3515
3516  if (ParentDC != D->getDeclContext()) {
3517    // We performed some kind of instantiation in the parent context,
3518    // so now we need to look into the instantiated parent context to
3519    // find the instantiation of the declaration D.
3520
3521    // If our context used to be dependent, we may need to instantiate
3522    // it before performing lookup into that context.
3523    bool IsBeingInstantiated = false;
3524    if (CXXRecordDecl *Spec = dyn_cast<CXXRecordDecl>(ParentDC)) {
3525      if (!Spec->isDependentContext()) {
3526        QualType T = Context.getTypeDeclType(Spec);
3527        const RecordType *Tag = T->getAs<RecordType>();
3528        assert(Tag && "type of non-dependent record is not a RecordType");
3529        if (Tag->isBeingDefined())
3530          IsBeingInstantiated = true;
3531        if (!Tag->isBeingDefined() &&
3532            RequireCompleteType(Loc, T, diag::err_incomplete_type))
3533          return 0;
3534
3535        ParentDC = Tag->getDecl();
3536      }
3537    }
3538
3539    NamedDecl *Result = 0;
3540    if (D->getDeclName()) {
3541      DeclContext::lookup_result Found = ParentDC->lookup(D->getDeclName());
3542      Result = findInstantiationOf(Context, D, Found.first, Found.second);
3543    } else {
3544      // Since we don't have a name for the entity we're looking for,
3545      // our only option is to walk through all of the declarations to
3546      // find that name. This will occur in a few cases:
3547      //
3548      //   - anonymous struct/union within a template
3549      //   - unnamed class/struct/union/enum within a template
3550      //
3551      // FIXME: Find a better way to find these instantiations!
3552      Result = findInstantiationOf(Context, D,
3553                                   ParentDC->decls_begin(),
3554                                   ParentDC->decls_end());
3555    }
3556
3557    if (!Result) {
3558      if (isa<UsingShadowDecl>(D)) {
3559        // UsingShadowDecls can instantiate to nothing because of using hiding.
3560      } else if (Diags.hasErrorOccurred()) {
3561        // We've already complained about something, so most likely this
3562        // declaration failed to instantiate. There's no point in complaining
3563        // further, since this is normal in invalid code.
3564      } else if (IsBeingInstantiated) {
3565        // The class in which this member exists is currently being
3566        // instantiated, and we haven't gotten around to instantiating this
3567        // member yet. This can happen when the code uses forward declarations
3568        // of member classes, and introduces ordering dependencies via
3569        // template instantiation.
3570        Diag(Loc, diag::err_member_not_yet_instantiated)
3571          << D->getDeclName()
3572          << Context.getTypeDeclType(cast<CXXRecordDecl>(ParentDC));
3573        Diag(D->getLocation(), diag::note_non_instantiated_member_here);
3574      } else if (EnumConstantDecl *ED = dyn_cast<EnumConstantDecl>(D)) {
3575        // This enumeration constant was found when the template was defined,
3576        // but can't be found in the instantiation. This can happen if an
3577        // unscoped enumeration member is explicitly specialized.
3578        EnumDecl *Enum = cast<EnumDecl>(ED->getLexicalDeclContext());
3579        EnumDecl *Spec = cast<EnumDecl>(FindInstantiatedDecl(Loc, Enum,
3580                                                             TemplateArgs));
3581        assert(Spec->getTemplateSpecializationKind() ==
3582                 TSK_ExplicitSpecialization);
3583        Diag(Loc, diag::err_enumerator_does_not_exist)
3584          << D->getDeclName()
3585          << Context.getTypeDeclType(cast<TypeDecl>(Spec->getDeclContext()));
3586        Diag(Spec->getLocation(), diag::note_enum_specialized_here)
3587          << Context.getTypeDeclType(Spec);
3588      } else {
3589        // We should have found something, but didn't.
3590        llvm_unreachable("Unable to find instantiation of declaration!");
3591      }
3592    }
3593
3594    D = Result;
3595  }
3596
3597  return D;
3598}
3599
3600/// \brief Performs template instantiation for all implicit template
3601/// instantiations we have seen until this point.
3602void Sema::PerformPendingInstantiations(bool LocalOnly) {
3603  // Load pending instantiations from the external source.
3604  if (!LocalOnly && ExternalSource) {
3605    SmallVector<PendingImplicitInstantiation, 4> Pending;
3606    ExternalSource->ReadPendingInstantiations(Pending);
3607    PendingInstantiations.insert(PendingInstantiations.begin(),
3608                                 Pending.begin(), Pending.end());
3609  }
3610
3611  while (!PendingLocalImplicitInstantiations.empty() ||
3612         (!LocalOnly && !PendingInstantiations.empty())) {
3613    PendingImplicitInstantiation Inst;
3614
3615    if (PendingLocalImplicitInstantiations.empty()) {
3616      Inst = PendingInstantiations.front();
3617      PendingInstantiations.pop_front();
3618    } else {
3619      Inst = PendingLocalImplicitInstantiations.front();
3620      PendingLocalImplicitInstantiations.pop_front();
3621    }
3622
3623    // Instantiate function definitions
3624    if (FunctionDecl *Function = dyn_cast<FunctionDecl>(Inst.first)) {
3625      PrettyDeclStackTraceEntry CrashInfo(*this, Function, SourceLocation(),
3626                                          "instantiating function definition");
3627      bool DefinitionRequired = Function->getTemplateSpecializationKind() ==
3628                                TSK_ExplicitInstantiationDefinition;
3629      InstantiateFunctionDefinition(/*FIXME:*/Inst.second, Function, true,
3630                                    DefinitionRequired);
3631      continue;
3632    }
3633
3634    // Instantiate static data member definitions.
3635    VarDecl *Var = cast<VarDecl>(Inst.first);
3636    assert(Var->isStaticDataMember() && "Not a static data member?");
3637
3638    // Don't try to instantiate declarations if the most recent redeclaration
3639    // is invalid.
3640    if (Var->getMostRecentDecl()->isInvalidDecl())
3641      continue;
3642
3643    // Check if the most recent declaration has changed the specialization kind
3644    // and removed the need for implicit instantiation.
3645    switch (Var->getMostRecentDecl()->getTemplateSpecializationKind()) {
3646    case TSK_Undeclared:
3647      llvm_unreachable("Cannot instantitiate an undeclared specialization.");
3648    case TSK_ExplicitInstantiationDeclaration:
3649    case TSK_ExplicitSpecialization:
3650      continue;  // No longer need to instantiate this type.
3651    case TSK_ExplicitInstantiationDefinition:
3652      // We only need an instantiation if the pending instantiation *is* the
3653      // explicit instantiation.
3654      if (Var != Var->getMostRecentDecl()) continue;
3655    case TSK_ImplicitInstantiation:
3656      break;
3657    }
3658
3659    PrettyDeclStackTraceEntry CrashInfo(*this, Var, Var->getLocation(),
3660                                        "instantiating static data member "
3661                                        "definition");
3662
3663    bool DefinitionRequired = Var->getTemplateSpecializationKind() ==
3664                              TSK_ExplicitInstantiationDefinition;
3665    InstantiateStaticDataMemberDefinition(/*FIXME:*/Inst.second, Var, true,
3666                                          DefinitionRequired);
3667  }
3668}
3669
3670void Sema::PerformDependentDiagnostics(const DeclContext *Pattern,
3671                       const MultiLevelTemplateArgumentList &TemplateArgs) {
3672  for (DeclContext::ddiag_iterator I = Pattern->ddiag_begin(),
3673         E = Pattern->ddiag_end(); I != E; ++I) {
3674    DependentDiagnostic *DD = *I;
3675
3676    switch (DD->getKind()) {
3677    case DependentDiagnostic::Access:
3678      HandleDependentAccessCheck(*DD, TemplateArgs);
3679      break;
3680    }
3681  }
3682}
3683