SemaTemplateInstantiateDecl.cpp revision 88dff5f420c1adb91b60e18defc4e732982df7bf 
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 "Sema.h"
13#include "clang/AST/ASTConsumer.h"
14#include "clang/AST/ASTContext.h"
15#include "clang/AST/DeclTemplate.h"
16#include "clang/AST/DeclVisitor.h"
17#include "clang/AST/Expr.h"
18#include "clang/Basic/PrettyStackTrace.h"
19#include "clang/Lex/Preprocessor.h"
20#include "llvm/Support/Compiler.h"
21
22using namespace clang;
23
24namespace {
25  class VISIBILITY_HIDDEN TemplateDeclInstantiator
26    : public DeclVisitor<TemplateDeclInstantiator, Decl *> {
27    Sema &SemaRef;
28    DeclContext *Owner;
29    const MultiLevelTemplateArgumentList &TemplateArgs;
30
31  public:
32    typedef Sema::OwningExprResult OwningExprResult;
33
34    TemplateDeclInstantiator(Sema &SemaRef, DeclContext *Owner,
35                             const MultiLevelTemplateArgumentList &TemplateArgs)
36      : SemaRef(SemaRef), Owner(Owner), TemplateArgs(TemplateArgs) { }
37
38    // FIXME: Once we get closer to completion, replace these manually-written
39    // declarations with automatically-generated ones from
40    // clang/AST/DeclNodes.def.
41    Decl *VisitTranslationUnitDecl(TranslationUnitDecl *D);
42    Decl *VisitNamespaceDecl(NamespaceDecl *D);
43    Decl *VisitTypedefDecl(TypedefDecl *D);
44    Decl *VisitVarDecl(VarDecl *D);
45    Decl *VisitFieldDecl(FieldDecl *D);
46    Decl *VisitStaticAssertDecl(StaticAssertDecl *D);
47    Decl *VisitEnumDecl(EnumDecl *D);
48    Decl *VisitEnumConstantDecl(EnumConstantDecl *D);
49    Decl *VisitFriendDecl(FriendDecl *D);
50    Decl *VisitFunctionDecl(FunctionDecl *D,
51                            TemplateParameterList *TemplateParams = 0);
52    Decl *VisitCXXRecordDecl(CXXRecordDecl *D);
53    Decl *VisitCXXMethodDecl(CXXMethodDecl *D,
54                             TemplateParameterList *TemplateParams = 0);
55    Decl *VisitCXXConstructorDecl(CXXConstructorDecl *D);
56    Decl *VisitCXXDestructorDecl(CXXDestructorDecl *D);
57    Decl *VisitCXXConversionDecl(CXXConversionDecl *D);
58    ParmVarDecl *VisitParmVarDecl(ParmVarDecl *D);
59    Decl *VisitClassTemplateDecl(ClassTemplateDecl *D);
60    Decl *VisitClassTemplatePartialSpecializationDecl(
61                                    ClassTemplatePartialSpecializationDecl *D);
62    Decl *VisitFunctionTemplateDecl(FunctionTemplateDecl *D);
63    Decl *VisitTemplateTypeParmDecl(TemplateTypeParmDecl *D);
64    Decl *VisitNonTypeTemplateParmDecl(NonTypeTemplateParmDecl *D);
65    Decl *VisitUnresolvedUsingDecl(UnresolvedUsingDecl *D);
66
67    // Base case. FIXME: Remove once we can instantiate everything.
68    Decl *VisitDecl(Decl *) {
69      assert(false && "Template instantiation of unknown declaration kind!");
70      return 0;
71    }
72
73    const LangOptions &getLangOptions() {
74      return SemaRef.getLangOptions();
75    }
76
77    // Helper functions for instantiating methods.
78    QualType SubstFunctionType(FunctionDecl *D,
79                             llvm::SmallVectorImpl<ParmVarDecl *> &Params);
80    bool InitFunctionInstantiation(FunctionDecl *New, FunctionDecl *Tmpl);
81    bool InitMethodInstantiation(CXXMethodDecl *New, CXXMethodDecl *Tmpl);
82
83    TemplateParameterList *
84      SubstTemplateParams(TemplateParameterList *List);
85
86    bool InstantiateClassTemplatePartialSpecialization(
87                                              ClassTemplateDecl *ClassTemplate,
88                           ClassTemplatePartialSpecializationDecl *PartialSpec);
89  };
90}
91
92Decl *
93TemplateDeclInstantiator::VisitTranslationUnitDecl(TranslationUnitDecl *D) {
94  assert(false && "Translation units cannot be instantiated");
95  return D;
96}
97
98Decl *
99TemplateDeclInstantiator::VisitNamespaceDecl(NamespaceDecl *D) {
100  assert(false && "Namespaces cannot be instantiated");
101  return D;
102}
103
104Decl *TemplateDeclInstantiator::VisitTypedefDecl(TypedefDecl *D) {
105  bool Invalid = false;
106  DeclaratorInfo *DI = D->getTypeDeclaratorInfo();
107  if (DI->getType()->isDependentType()) {
108    DI = SemaRef.SubstType(DI, TemplateArgs,
109                           D->getLocation(), D->getDeclName());
110    if (!DI) {
111      Invalid = true;
112      DI = SemaRef.Context.getTrivialDeclaratorInfo(SemaRef.Context.IntTy);
113    }
114  }
115
116  // Create the new typedef
117  TypedefDecl *Typedef
118    = TypedefDecl::Create(SemaRef.Context, Owner, D->getLocation(),
119                          D->getIdentifier(), DI);
120  if (Invalid)
121    Typedef->setInvalidDecl();
122
123  Owner->addDecl(Typedef);
124
125  return Typedef;
126}
127
128Decl *TemplateDeclInstantiator::VisitVarDecl(VarDecl *D) {
129  // Do substitution on the type of the declaration
130  DeclaratorInfo *DI = SemaRef.SubstType(D->getDeclaratorInfo(),
131                                         TemplateArgs,
132                                         D->getTypeSpecStartLoc(),
133                                         D->getDeclName());
134  if (!DI)
135    return 0;
136
137  // Build the instantiated declaration
138  VarDecl *Var = VarDecl::Create(SemaRef.Context, Owner,
139                                 D->getLocation(), D->getIdentifier(),
140                                 DI->getType(), DI,
141                                 D->getStorageClass());
142  Var->setThreadSpecified(D->isThreadSpecified());
143  Var->setCXXDirectInitializer(D->hasCXXDirectInitializer());
144  Var->setDeclaredInCondition(D->isDeclaredInCondition());
145
146  // If we are instantiating a static data member defined
147  // out-of-line, the instantiation will have the same lexical
148  // context (which will be a namespace scope) as the template.
149  if (D->isOutOfLine())
150    Var->setLexicalDeclContext(D->getLexicalDeclContext());
151
152  // FIXME: In theory, we could have a previous declaration for variables that
153  // are not static data members.
154  bool Redeclaration = false;
155  SemaRef.CheckVariableDeclaration(Var, 0, Redeclaration);
156
157  if (D->isOutOfLine()) {
158    D->getLexicalDeclContext()->addDecl(Var);
159    Owner->makeDeclVisibleInContext(Var);
160  } else {
161    Owner->addDecl(Var);
162  }
163
164  // Link instantiations of static data members back to the template from
165  // which they were instantiated.
166  if (Var->isStaticDataMember())
167    SemaRef.Context.setInstantiatedFromStaticDataMember(Var, D,
168                                                        TSK_ImplicitInstantiation);
169
170  if (D->getInit()) {
171    OwningExprResult Init
172      = SemaRef.SubstExpr(D->getInit(), TemplateArgs);
173    if (Init.isInvalid())
174      Var->setInvalidDecl();
175    else if (ParenListExpr *PLE = dyn_cast<ParenListExpr>((Expr *)Init.get())) {
176      // FIXME: We're faking all of the comma locations, which is suboptimal.
177      // Do we even need these comma locations?
178      llvm::SmallVector<SourceLocation, 4> FakeCommaLocs;
179      if (PLE->getNumExprs() > 0) {
180        FakeCommaLocs.reserve(PLE->getNumExprs() - 1);
181        for (unsigned I = 0, N = PLE->getNumExprs() - 1; I != N; ++I) {
182          Expr *E = PLE->getExpr(I)->Retain();
183          FakeCommaLocs.push_back(
184                                SemaRef.PP.getLocForEndOfToken(E->getLocEnd()));
185        }
186        PLE->getExpr(PLE->getNumExprs() - 1)->Retain();
187      }
188
189      // Add the direct initializer to the declaration.
190      SemaRef.AddCXXDirectInitializerToDecl(Sema::DeclPtrTy::make(Var),
191                                            PLE->getLParenLoc(),
192                                            Sema::MultiExprArg(SemaRef,
193                                                       (void**)PLE->getExprs(),
194                                                           PLE->getNumExprs()),
195                                            FakeCommaLocs.data(),
196                                            PLE->getRParenLoc());
197
198      // When Init is destroyed, it will destroy the instantiated ParenListExpr;
199      // we've explicitly retained all of its subexpressions already.
200    } else
201      SemaRef.AddInitializerToDecl(Sema::DeclPtrTy::make(Var), move(Init),
202                                   D->hasCXXDirectInitializer());
203  } else if (!Var->isStaticDataMember() || Var->isOutOfLine())
204    SemaRef.ActOnUninitializedDecl(Sema::DeclPtrTy::make(Var), false);
205
206  return Var;
207}
208
209Decl *TemplateDeclInstantiator::VisitFieldDecl(FieldDecl *D) {
210  bool Invalid = false;
211  DeclaratorInfo *DI = D->getDeclaratorInfo();
212  if (DI->getType()->isDependentType())  {
213    DI = SemaRef.SubstType(DI, TemplateArgs,
214                           D->getLocation(), D->getDeclName());
215    if (!DI) {
216      DI = D->getDeclaratorInfo();
217      Invalid = true;
218    } else if (DI->getType()->isFunctionType()) {
219      // C++ [temp.arg.type]p3:
220      //   If a declaration acquires a function type through a type
221      //   dependent on a template-parameter and this causes a
222      //   declaration that does not use the syntactic form of a
223      //   function declarator to have function type, the program is
224      //   ill-formed.
225      SemaRef.Diag(D->getLocation(), diag::err_field_instantiates_to_function)
226        << DI->getType();
227      Invalid = true;
228    }
229  }
230
231  Expr *BitWidth = D->getBitWidth();
232  if (Invalid)
233    BitWidth = 0;
234  else if (BitWidth) {
235    // The bit-width expression is not potentially evaluated.
236    EnterExpressionEvaluationContext Unevaluated(SemaRef, Action::Unevaluated);
237
238    OwningExprResult InstantiatedBitWidth
239      = SemaRef.SubstExpr(BitWidth, TemplateArgs);
240    if (InstantiatedBitWidth.isInvalid()) {
241      Invalid = true;
242      BitWidth = 0;
243    } else
244      BitWidth = InstantiatedBitWidth.takeAs<Expr>();
245  }
246
247  FieldDecl *Field = SemaRef.CheckFieldDecl(D->getDeclName(),
248                                            DI->getType(), DI,
249                                            cast<RecordDecl>(Owner),
250                                            D->getLocation(),
251                                            D->isMutable(),
252                                            BitWidth,
253                                            D->getTypeSpecStartLoc(),
254                                            D->getAccess(),
255                                            0);
256  if (!Field) {
257    cast<Decl>(Owner)->setInvalidDecl();
258    return 0;
259  }
260
261  if (Invalid)
262    Field->setInvalidDecl();
263
264  if (!Field->getDeclName()) {
265    // Keep track of where this decl came from.
266    SemaRef.Context.setInstantiatedFromUnnamedFieldDecl(Field, D);
267  }
268
269  Field->setImplicit(D->isImplicit());
270  Owner->addDecl(Field);
271
272  return Field;
273}
274
275Decl *TemplateDeclInstantiator::VisitFriendDecl(FriendDecl *D) {
276  FriendDecl::FriendUnion FU;
277
278  // Handle friend type expressions by simply substituting template
279  // parameters into the pattern type.
280  if (Type *Ty = D->getFriendType()) {
281    QualType T = SemaRef.SubstType(QualType(Ty,0), TemplateArgs,
282                                   D->getLocation(), DeclarationName());
283    if (T.isNull()) return 0;
284
285    assert(getLangOptions().CPlusPlus0x || T->isRecordType());
286    FU = T.getTypePtr();
287
288  // Handle everything else by appropriate substitution.
289  } else {
290    NamedDecl *ND = D->getFriendDecl();
291    assert(ND && "friend decl must be a decl or a type!");
292
293    // FIXME: We have a problem here, because the nested call to Visit(ND)
294    // will inject the thing that the friend references into the current
295    // owner, which is wrong.
296    Decl *NewND = Visit(ND);
297    if (!NewND) return 0;
298
299    FU = cast<NamedDecl>(NewND);
300  }
301
302  FriendDecl *FD =
303    FriendDecl::Create(SemaRef.Context, Owner, D->getLocation(), FU,
304                       D->getFriendLoc());
305  FD->setAccess(AS_public);
306  Owner->addDecl(FD);
307  return FD;
308}
309
310Decl *TemplateDeclInstantiator::VisitStaticAssertDecl(StaticAssertDecl *D) {
311  Expr *AssertExpr = D->getAssertExpr();
312
313  // The expression in a static assertion is not potentially evaluated.
314  EnterExpressionEvaluationContext Unevaluated(SemaRef, Action::Unevaluated);
315
316  OwningExprResult InstantiatedAssertExpr
317    = SemaRef.SubstExpr(AssertExpr, TemplateArgs);
318  if (InstantiatedAssertExpr.isInvalid())
319    return 0;
320
321  OwningExprResult Message(SemaRef, D->getMessage());
322  D->getMessage()->Retain();
323  Decl *StaticAssert
324    = SemaRef.ActOnStaticAssertDeclaration(D->getLocation(),
325                                           move(InstantiatedAssertExpr),
326                                           move(Message)).getAs<Decl>();
327  return StaticAssert;
328}
329
330Decl *TemplateDeclInstantiator::VisitEnumDecl(EnumDecl *D) {
331  EnumDecl *Enum = EnumDecl::Create(SemaRef.Context, Owner,
332                                    D->getLocation(), D->getIdentifier(),
333                                    D->getTagKeywordLoc(),
334                                    /*PrevDecl=*/0);
335  Enum->setInstantiationOfMemberEnum(D);
336  Enum->setAccess(D->getAccess());
337  Owner->addDecl(Enum);
338  Enum->startDefinition();
339
340  llvm::SmallVector<Sema::DeclPtrTy, 4> Enumerators;
341
342  EnumConstantDecl *LastEnumConst = 0;
343  for (EnumDecl::enumerator_iterator EC = D->enumerator_begin(),
344         ECEnd = D->enumerator_end();
345       EC != ECEnd; ++EC) {
346    // The specified value for the enumerator.
347    OwningExprResult Value = SemaRef.Owned((Expr *)0);
348    if (Expr *UninstValue = EC->getInitExpr()) {
349      // The enumerator's value expression is not potentially evaluated.
350      EnterExpressionEvaluationContext Unevaluated(SemaRef,
351                                                   Action::Unevaluated);
352
353      Value = SemaRef.SubstExpr(UninstValue, TemplateArgs);
354    }
355
356    // Drop the initial value and continue.
357    bool isInvalid = false;
358    if (Value.isInvalid()) {
359      Value = SemaRef.Owned((Expr *)0);
360      isInvalid = true;
361    }
362
363    EnumConstantDecl *EnumConst
364      = SemaRef.CheckEnumConstant(Enum, LastEnumConst,
365                                  EC->getLocation(), EC->getIdentifier(),
366                                  move(Value));
367
368    if (isInvalid) {
369      if (EnumConst)
370        EnumConst->setInvalidDecl();
371      Enum->setInvalidDecl();
372    }
373
374    if (EnumConst) {
375      Enum->addDecl(EnumConst);
376      Enumerators.push_back(Sema::DeclPtrTy::make(EnumConst));
377      LastEnumConst = EnumConst;
378    }
379  }
380
381  // FIXME: Fixup LBraceLoc and RBraceLoc
382  // FIXME: Empty Scope and AttributeList (required to handle attribute packed).
383  SemaRef.ActOnEnumBody(Enum->getLocation(), SourceLocation(), SourceLocation(),
384                        Sema::DeclPtrTy::make(Enum),
385                        &Enumerators[0], Enumerators.size(),
386                        0, 0);
387
388  return Enum;
389}
390
391Decl *TemplateDeclInstantiator::VisitEnumConstantDecl(EnumConstantDecl *D) {
392  assert(false && "EnumConstantDecls can only occur within EnumDecls.");
393  return 0;
394}
395
396namespace {
397  class SortDeclByLocation {
398    SourceManager &SourceMgr;
399
400  public:
401    explicit SortDeclByLocation(SourceManager &SourceMgr)
402      : SourceMgr(SourceMgr) { }
403
404    bool operator()(const Decl *X, const Decl *Y) const {
405      return SourceMgr.isBeforeInTranslationUnit(X->getLocation(),
406                                                 Y->getLocation());
407    }
408  };
409}
410
411Decl *TemplateDeclInstantiator::VisitClassTemplateDecl(ClassTemplateDecl *D) {
412  TemplateParameterList *TempParams = D->getTemplateParameters();
413  TemplateParameterList *InstParams = SubstTemplateParams(TempParams);
414  if (!InstParams)
415    return NULL;
416
417  CXXRecordDecl *Pattern = D->getTemplatedDecl();
418  CXXRecordDecl *RecordInst
419    = CXXRecordDecl::Create(SemaRef.Context, Pattern->getTagKind(), Owner,
420                            Pattern->getLocation(), Pattern->getIdentifier(),
421                            Pattern->getTagKeywordLoc(), /*PrevDecl=*/ NULL,
422                            /*DelayTypeCreation=*/true);
423
424  ClassTemplateDecl *Inst
425    = ClassTemplateDecl::Create(SemaRef.Context, Owner, D->getLocation(),
426                                D->getIdentifier(), InstParams, RecordInst, 0);
427  RecordInst->setDescribedClassTemplate(Inst);
428  if (D->getFriendObjectKind())
429    Inst->setObjectOfFriendDecl(true);
430  else
431    Inst->setAccess(D->getAccess());
432  Inst->setInstantiatedFromMemberTemplate(D);
433
434  // Trigger creation of the type for the instantiation.
435  SemaRef.Context.getTypeDeclType(RecordInst);
436
437  // We're done with friends now.
438  if (Inst->getFriendObjectKind())
439    return Inst;
440
441  Owner->addDecl(Inst);
442
443  // First, we sort the partial specializations by location, so
444  // that we instantiate them in the order they were declared.
445  llvm::SmallVector<ClassTemplatePartialSpecializationDecl *, 4> PartialSpecs;
446  for (llvm::FoldingSet<ClassTemplatePartialSpecializationDecl>::iterator
447         P = D->getPartialSpecializations().begin(),
448         PEnd = D->getPartialSpecializations().end();
449       P != PEnd; ++P)
450    PartialSpecs.push_back(&*P);
451  std::sort(PartialSpecs.begin(), PartialSpecs.end(),
452            SortDeclByLocation(SemaRef.SourceMgr));
453
454  // Instantiate all of the partial specializations of this member class
455  // template.
456  for (unsigned I = 0, N = PartialSpecs.size(); I != N; ++I)
457    InstantiateClassTemplatePartialSpecialization(Inst, PartialSpecs[I]);
458
459  return Inst;
460}
461
462Decl *
463TemplateDeclInstantiator::VisitClassTemplatePartialSpecializationDecl(
464                                   ClassTemplatePartialSpecializationDecl *D) {
465  ClassTemplateDecl *ClassTemplate = D->getSpecializedTemplate();
466
467  // Lookup the already-instantiated declaration in the instantiation
468  // of the class template and return that.
469  DeclContext::lookup_result Found
470    = Owner->lookup(ClassTemplate->getDeclName());
471  if (Found.first == Found.second)
472    return 0;
473
474  ClassTemplateDecl *InstClassTemplate
475    = dyn_cast<ClassTemplateDecl>(*Found.first);
476  if (!InstClassTemplate)
477    return 0;
478
479  Decl *DCanon = D->getCanonicalDecl();
480  for (llvm::FoldingSet<ClassTemplatePartialSpecializationDecl>::iterator
481            P = InstClassTemplate->getPartialSpecializations().begin(),
482         PEnd = InstClassTemplate->getPartialSpecializations().end();
483       P != PEnd; ++P) {
484    if (P->getInstantiatedFromMember()->getCanonicalDecl() == DCanon)
485      return &*P;
486  }
487
488  return 0;
489}
490
491Decl *
492TemplateDeclInstantiator::VisitFunctionTemplateDecl(FunctionTemplateDecl *D) {
493  // FIXME: Dig out the out-of-line definition of this function template?
494
495  TemplateParameterList *TempParams = D->getTemplateParameters();
496  TemplateParameterList *InstParams = SubstTemplateParams(TempParams);
497  if (!InstParams)
498    return NULL;
499
500  FunctionDecl *Instantiated = 0;
501  if (CXXMethodDecl *DMethod = dyn_cast<CXXMethodDecl>(D->getTemplatedDecl()))
502    Instantiated = cast_or_null<FunctionDecl>(VisitCXXMethodDecl(DMethod,
503                                                                 InstParams));
504  else
505    Instantiated = cast_or_null<FunctionDecl>(VisitFunctionDecl(
506                                                          D->getTemplatedDecl(),
507                                                                InstParams));
508
509  if (!Instantiated)
510    return 0;
511
512  // Link the instantiated function template declaration to the function
513  // template from which it was instantiated.
514  FunctionTemplateDecl *InstTemplate
515    = Instantiated->getDescribedFunctionTemplate();
516  InstTemplate->setAccess(D->getAccess());
517  assert(InstTemplate &&
518         "VisitFunctionDecl/CXXMethodDecl didn't create a template!");
519  if (!InstTemplate->getInstantiatedFromMemberTemplate())
520    InstTemplate->setInstantiatedFromMemberTemplate(D);
521
522  // Add non-friends into the owner.
523  if (!InstTemplate->getFriendObjectKind())
524    Owner->addDecl(InstTemplate);
525  return InstTemplate;
526}
527
528Decl *TemplateDeclInstantiator::VisitCXXRecordDecl(CXXRecordDecl *D) {
529  CXXRecordDecl *PrevDecl = 0;
530  if (D->isInjectedClassName())
531    PrevDecl = cast<CXXRecordDecl>(Owner);
532
533  CXXRecordDecl *Record
534    = CXXRecordDecl::Create(SemaRef.Context, D->getTagKind(), Owner,
535                            D->getLocation(), D->getIdentifier(),
536                            D->getTagKeywordLoc(), PrevDecl);
537  Record->setImplicit(D->isImplicit());
538  // FIXME: Check against AS_none is an ugly hack to work around the issue that
539  // the tag decls introduced by friend class declarations don't have an access
540  // specifier. Remove once this area of the code gets sorted out.
541  if (D->getAccess() != AS_none)
542    Record->setAccess(D->getAccess());
543  if (!D->isInjectedClassName())
544    Record->setInstantiationOfMemberClass(D, TSK_ImplicitInstantiation);
545
546  // If the original function was part of a friend declaration,
547  // inherit its namespace state.
548  if (Decl::FriendObjectKind FOK = D->getFriendObjectKind())
549    Record->setObjectOfFriendDecl(FOK == Decl::FOK_Declared);
550
551  Record->setAnonymousStructOrUnion(D->isAnonymousStructOrUnion());
552
553  Owner->addDecl(Record);
554  return Record;
555}
556
557/// Normal class members are of more specific types and therefore
558/// don't make it here.  This function serves two purposes:
559///   1) instantiating function templates
560///   2) substituting friend declarations
561/// FIXME: preserve function definitions in case #2
562  Decl *TemplateDeclInstantiator::VisitFunctionDecl(FunctionDecl *D,
563                                       TemplateParameterList *TemplateParams) {
564  // Check whether there is already a function template specialization for
565  // this declaration.
566  FunctionTemplateDecl *FunctionTemplate = D->getDescribedFunctionTemplate();
567  void *InsertPos = 0;
568  if (FunctionTemplate && !TemplateParams) {
569    llvm::FoldingSetNodeID ID;
570    FunctionTemplateSpecializationInfo::Profile(ID,
571                             TemplateArgs.getInnermost().getFlatArgumentList(),
572                                       TemplateArgs.getInnermost().flat_size(),
573                                                SemaRef.Context);
574
575    FunctionTemplateSpecializationInfo *Info
576      = FunctionTemplate->getSpecializations().FindNodeOrInsertPos(ID,
577                                                                   InsertPos);
578
579    // If we already have a function template specialization, return it.
580    if (Info)
581      return Info->Function;
582  }
583
584  Sema::LocalInstantiationScope Scope(SemaRef);
585
586  llvm::SmallVector<ParmVarDecl *, 4> Params;
587  QualType T = SubstFunctionType(D, Params);
588  if (T.isNull())
589    return 0;
590
591  // Build the instantiated method declaration.
592  DeclContext *DC = SemaRef.FindInstantiatedContext(D->getDeclContext(),
593                                                    TemplateArgs);
594  FunctionDecl *Function =
595      FunctionDecl::Create(SemaRef.Context, DC, D->getLocation(),
596                           D->getDeclName(), T, D->getDeclaratorInfo(),
597                           D->getStorageClass(),
598                           D->isInlineSpecified(), D->hasWrittenPrototype());
599  Function->setLexicalDeclContext(Owner);
600
601  // Attach the parameters
602  for (unsigned P = 0; P < Params.size(); ++P)
603    Params[P]->setOwningFunction(Function);
604  Function->setParams(SemaRef.Context, Params.data(), Params.size());
605
606  if (TemplateParams) {
607    // Our resulting instantiation is actually a function template, since we
608    // are substituting only the outer template parameters. For example, given
609    //
610    //   template<typename T>
611    //   struct X {
612    //     template<typename U> friend void f(T, U);
613    //   };
614    //
615    //   X<int> x;
616    //
617    // We are instantiating the friend function template "f" within X<int>,
618    // which means substituting int for T, but leaving "f" as a friend function
619    // template.
620    // Build the function template itself.
621    FunctionTemplate = FunctionTemplateDecl::Create(SemaRef.Context, Owner,
622                                                    Function->getLocation(),
623                                                    Function->getDeclName(),
624                                                    TemplateParams, Function);
625    Function->setDescribedFunctionTemplate(FunctionTemplate);
626    FunctionTemplate->setLexicalDeclContext(D->getLexicalDeclContext());
627  }
628
629  if (InitFunctionInstantiation(Function, D))
630    Function->setInvalidDecl();
631
632  bool Redeclaration = false;
633  bool OverloadableAttrRequired = false;
634
635  NamedDecl *PrevDecl = 0;
636  if (TemplateParams || !FunctionTemplate) {
637    // Look only into the namespace where the friend would be declared to
638    // find a previous declaration. This is the innermost enclosing namespace,
639    // as described in ActOnFriendFunctionDecl.
640    Sema::LookupResult R;
641    SemaRef.LookupQualifiedName(R, DC, Function->getDeclName(),
642                              Sema::LookupOrdinaryName, true);
643
644    PrevDecl = R.getAsSingleDecl(SemaRef.Context);
645
646    // In C++, the previous declaration we find might be a tag type
647    // (class or enum). In this case, the new declaration will hide the
648    // tag type. Note that this does does not apply if we're declaring a
649    // typedef (C++ [dcl.typedef]p4).
650    if (PrevDecl && PrevDecl->getIdentifierNamespace() == Decl::IDNS_Tag)
651      PrevDecl = 0;
652  }
653
654  SemaRef.CheckFunctionDeclaration(Function, PrevDecl, false, Redeclaration,
655                                   /*FIXME:*/OverloadableAttrRequired);
656
657  // If the original function was part of a friend declaration,
658  // inherit its namespace state and add it to the owner.
659  NamedDecl *FromFriendD
660      = TemplateParams? cast<NamedDecl>(D->getDescribedFunctionTemplate()) : D;
661  if (FromFriendD->getFriendObjectKind()) {
662    NamedDecl *ToFriendD = 0;
663    if (TemplateParams) {
664      ToFriendD = cast<NamedDecl>(FunctionTemplate);
665      PrevDecl = FunctionTemplate->getPreviousDeclaration();
666    } else {
667      ToFriendD = Function;
668      PrevDecl = Function->getPreviousDeclaration();
669    }
670    ToFriendD->setObjectOfFriendDecl(PrevDecl != NULL);
671    if (!Owner->isDependentContext() && !PrevDecl)
672      DC->makeDeclVisibleInContext(ToFriendD, /* Recoverable = */ false);
673
674    if (!TemplateParams)
675      Function->setInstantiationOfMemberFunction(D, TSK_ImplicitInstantiation);
676  }
677
678  if (FunctionTemplate && !TemplateParams) {
679    // Record this function template specialization.
680    Function->setFunctionTemplateSpecialization(SemaRef.Context,
681                                                FunctionTemplate,
682                                                &TemplateArgs.getInnermost(),
683                                                InsertPos);
684  }
685
686  return Function;
687}
688
689Decl *
690TemplateDeclInstantiator::VisitCXXMethodDecl(CXXMethodDecl *D,
691                                      TemplateParameterList *TemplateParams) {
692  FunctionTemplateDecl *FunctionTemplate = D->getDescribedFunctionTemplate();
693  void *InsertPos = 0;
694  if (FunctionTemplate && !TemplateParams) {
695    // We are creating a function template specialization from a function
696    // template. Check whether there is already a function template
697    // specialization for this particular set of template arguments.
698    llvm::FoldingSetNodeID ID;
699    FunctionTemplateSpecializationInfo::Profile(ID,
700                            TemplateArgs.getInnermost().getFlatArgumentList(),
701                                      TemplateArgs.getInnermost().flat_size(),
702                                                SemaRef.Context);
703
704    FunctionTemplateSpecializationInfo *Info
705      = FunctionTemplate->getSpecializations().FindNodeOrInsertPos(ID,
706                                                                   InsertPos);
707
708    // If we already have a function template specialization, return it.
709    if (Info)
710      return Info->Function;
711  }
712
713  Sema::LocalInstantiationScope Scope(SemaRef);
714
715  llvm::SmallVector<ParmVarDecl *, 4> Params;
716  QualType T = SubstFunctionType(D, Params);
717  if (T.isNull())
718    return 0;
719
720  // Build the instantiated method declaration.
721  CXXRecordDecl *Record = cast<CXXRecordDecl>(Owner);
722  CXXMethodDecl *Method = 0;
723
724  DeclarationName Name = D->getDeclName();
725  if (CXXConstructorDecl *Constructor = dyn_cast<CXXConstructorDecl>(D)) {
726    QualType ClassTy = SemaRef.Context.getTypeDeclType(Record);
727    Name = SemaRef.Context.DeclarationNames.getCXXConstructorName(
728                                    SemaRef.Context.getCanonicalType(ClassTy));
729    Method = CXXConstructorDecl::Create(SemaRef.Context, Record,
730                                        Constructor->getLocation(),
731                                        Name, T,
732                                        Constructor->getDeclaratorInfo(),
733                                        Constructor->isExplicit(),
734                                        Constructor->isInlineSpecified(), false);
735  } else if (CXXDestructorDecl *Destructor = dyn_cast<CXXDestructorDecl>(D)) {
736    QualType ClassTy = SemaRef.Context.getTypeDeclType(Record);
737    Name = SemaRef.Context.DeclarationNames.getCXXDestructorName(
738                                   SemaRef.Context.getCanonicalType(ClassTy));
739    Method = CXXDestructorDecl::Create(SemaRef.Context, Record,
740                                       Destructor->getLocation(), Name,
741                                       T, Destructor->isInlineSpecified(), false);
742  } else if (CXXConversionDecl *Conversion = dyn_cast<CXXConversionDecl>(D)) {
743    CanQualType ConvTy
744      = SemaRef.Context.getCanonicalType(
745                                      T->getAs<FunctionType>()->getResultType());
746    Name = SemaRef.Context.DeclarationNames.getCXXConversionFunctionName(
747                                                                      ConvTy);
748    Method = CXXConversionDecl::Create(SemaRef.Context, Record,
749                                       Conversion->getLocation(), Name,
750                                       T, Conversion->getDeclaratorInfo(),
751                                       Conversion->isInlineSpecified(),
752                                       Conversion->isExplicit());
753  } else {
754    Method = CXXMethodDecl::Create(SemaRef.Context, Record, D->getLocation(),
755                                   D->getDeclName(), T, D->getDeclaratorInfo(),
756                                   D->isStatic(), D->isInlineSpecified());
757  }
758
759  if (TemplateParams) {
760    // Our resulting instantiation is actually a function template, since we
761    // are substituting only the outer template parameters. For example, given
762    //
763    //   template<typename T>
764    //   struct X {
765    //     template<typename U> void f(T, U);
766    //   };
767    //
768    //   X<int> x;
769    //
770    // We are instantiating the member template "f" within X<int>, which means
771    // substituting int for T, but leaving "f" as a member function template.
772    // Build the function template itself.
773    FunctionTemplate = FunctionTemplateDecl::Create(SemaRef.Context, Record,
774                                                    Method->getLocation(),
775                                                    Method->getDeclName(),
776                                                    TemplateParams, Method);
777    if (D->isOutOfLine())
778      FunctionTemplate->setLexicalDeclContext(D->getLexicalDeclContext());
779    Method->setDescribedFunctionTemplate(FunctionTemplate);
780  } else if (!FunctionTemplate)
781    Method->setInstantiationOfMemberFunction(D, TSK_ImplicitInstantiation);
782
783  // If we are instantiating a member function defined
784  // out-of-line, the instantiation will have the same lexical
785  // context (which will be a namespace scope) as the template.
786  if (D->isOutOfLine())
787    Method->setLexicalDeclContext(D->getLexicalDeclContext());
788
789  // Attach the parameters
790  for (unsigned P = 0; P < Params.size(); ++P)
791    Params[P]->setOwningFunction(Method);
792  Method->setParams(SemaRef.Context, Params.data(), Params.size());
793
794  if (InitMethodInstantiation(Method, D))
795    Method->setInvalidDecl();
796
797  NamedDecl *PrevDecl = 0;
798
799  if (!FunctionTemplate || TemplateParams) {
800    Sema::LookupResult R;
801    SemaRef.LookupQualifiedName(R, Owner, Name, Sema::LookupOrdinaryName, true);
802    PrevDecl = R.getAsSingleDecl(SemaRef.Context);
803
804    // In C++, the previous declaration we find might be a tag type
805    // (class or enum). In this case, the new declaration will hide the
806    // tag type. Note that this does does not apply if we're declaring a
807    // typedef (C++ [dcl.typedef]p4).
808    if (PrevDecl && PrevDecl->getIdentifierNamespace() == Decl::IDNS_Tag)
809      PrevDecl = 0;
810  }
811
812  if (FunctionTemplate && !TemplateParams)
813    // Record this function template specialization.
814    Method->setFunctionTemplateSpecialization(SemaRef.Context,
815                                              FunctionTemplate,
816                                              &TemplateArgs.getInnermost(),
817                                              InsertPos);
818
819  bool Redeclaration = false;
820  bool OverloadableAttrRequired = false;
821  SemaRef.CheckFunctionDeclaration(Method, PrevDecl, false, Redeclaration,
822                                   /*FIXME:*/OverloadableAttrRequired);
823
824  if (!FunctionTemplate && (!Method->isInvalidDecl() || !PrevDecl) &&
825      !Method->getFriendObjectKind())
826    Owner->addDecl(Method);
827
828  return Method;
829}
830
831Decl *TemplateDeclInstantiator::VisitCXXConstructorDecl(CXXConstructorDecl *D) {
832  return VisitCXXMethodDecl(D);
833}
834
835Decl *TemplateDeclInstantiator::VisitCXXDestructorDecl(CXXDestructorDecl *D) {
836  return VisitCXXMethodDecl(D);
837}
838
839Decl *TemplateDeclInstantiator::VisitCXXConversionDecl(CXXConversionDecl *D) {
840  return VisitCXXMethodDecl(D);
841}
842
843ParmVarDecl *TemplateDeclInstantiator::VisitParmVarDecl(ParmVarDecl *D) {
844  QualType T;
845  DeclaratorInfo *DI = D->getDeclaratorInfo();
846  if (DI) {
847    DI = SemaRef.SubstType(DI, TemplateArgs, D->getLocation(),
848                           D->getDeclName());
849    if (DI) T = DI->getType();
850  } else {
851    T = SemaRef.SubstType(D->getType(), TemplateArgs, D->getLocation(),
852                          D->getDeclName());
853    DI = 0;
854  }
855
856  if (T.isNull())
857    return 0;
858
859  T = SemaRef.adjustParameterType(T);
860
861  // Allocate the parameter
862  ParmVarDecl *Param
863    = ParmVarDecl::Create(SemaRef.Context, Owner, D->getLocation(),
864                          D->getIdentifier(), T, DI, D->getStorageClass(), 0);
865
866  // Mark the default argument as being uninstantiated.
867  if (D->hasUninstantiatedDefaultArg())
868    Param->setUninstantiatedDefaultArg(D->getUninstantiatedDefaultArg());
869  else if (Expr *Arg = D->getDefaultArg())
870    Param->setUninstantiatedDefaultArg(Arg);
871
872  // Note: we don't try to instantiate function parameters until after
873  // we've instantiated the function's type. Therefore, we don't have
874  // to check for 'void' parameter types here.
875  SemaRef.CurrentInstantiationScope->InstantiatedLocal(D, Param);
876  return Param;
877}
878
879Decl *TemplateDeclInstantiator::VisitTemplateTypeParmDecl(
880                                                    TemplateTypeParmDecl *D) {
881  // TODO: don't always clone when decls are refcounted.
882  const Type* T = D->getTypeForDecl();
883  assert(T->isTemplateTypeParmType());
884  const TemplateTypeParmType *TTPT = T->getAs<TemplateTypeParmType>();
885
886  TemplateTypeParmDecl *Inst =
887    TemplateTypeParmDecl::Create(SemaRef.Context, Owner, D->getLocation(),
888                                 TTPT->getDepth(), TTPT->getIndex(),
889                                 TTPT->getName(),
890                                 D->wasDeclaredWithTypename(),
891                                 D->isParameterPack());
892
893  // FIXME: Do we actually want to perform substitution here? I don't think
894  // we do.
895  if (D->hasDefaultArgument()) {
896    DeclaratorInfo *DefaultPattern = D->getDefaultArgumentInfo();
897    DeclaratorInfo *DefaultInst
898      = SemaRef.SubstType(DefaultPattern, TemplateArgs,
899                          D->getDefaultArgumentLoc(),
900                          D->getDeclName());
901
902    Inst->setDefaultArgument(DefaultInst,
903                             D->defaultArgumentWasInherited() /* preserve? */);
904  }
905
906  return Inst;
907}
908
909Decl *TemplateDeclInstantiator::VisitNonTypeTemplateParmDecl(
910                                                 NonTypeTemplateParmDecl *D) {
911  // Substitute into the type of the non-type template parameter.
912  QualType T;
913  DeclaratorInfo *DI = D->getDeclaratorInfo();
914  if (DI) {
915    DI = SemaRef.SubstType(DI, TemplateArgs, D->getLocation(),
916                           D->getDeclName());
917    if (DI) T = DI->getType();
918  } else {
919    T = SemaRef.SubstType(D->getType(), TemplateArgs, D->getLocation(),
920                          D->getDeclName());
921    DI = 0;
922  }
923  if (T.isNull())
924    return 0;
925
926  // Check that this type is acceptable for a non-type template parameter.
927  bool Invalid = false;
928  T = SemaRef.CheckNonTypeTemplateParameterType(T, D->getLocation());
929  if (T.isNull()) {
930    T = SemaRef.Context.IntTy;
931    Invalid = true;
932  }
933
934  NonTypeTemplateParmDecl *Param
935    = NonTypeTemplateParmDecl::Create(SemaRef.Context, Owner, D->getLocation(),
936                                      D->getDepth() - 1, D->getPosition(),
937                                      D->getIdentifier(), T, DI);
938  if (Invalid)
939    Param->setInvalidDecl();
940
941  Param->setDefaultArgument(D->getDefaultArgument());
942  return Param;
943}
944
945Decl *
946TemplateDeclInstantiator::VisitUnresolvedUsingDecl(UnresolvedUsingDecl *D) {
947  NestedNameSpecifier *NNS =
948    SemaRef.SubstNestedNameSpecifier(D->getTargetNestedNameSpecifier(),
949                                     D->getTargetNestedNameRange(),
950                                     TemplateArgs);
951  if (!NNS)
952    return 0;
953
954  CXXScopeSpec SS;
955  SS.setRange(D->getTargetNestedNameRange());
956  SS.setScopeRep(NNS);
957
958  NamedDecl *UD =
959    SemaRef.BuildUsingDeclaration(D->getLocation(), SS,
960                                  D->getTargetNameLocation(),
961                                  D->getTargetName(), 0, D->isTypeName());
962  if (UD)
963    SemaRef.Context.setInstantiatedFromUnresolvedUsingDecl(cast<UsingDecl>(UD),
964                                                           D);
965  return UD;
966}
967
968Decl *Sema::SubstDecl(Decl *D, DeclContext *Owner,
969                      const MultiLevelTemplateArgumentList &TemplateArgs) {
970  TemplateDeclInstantiator Instantiator(*this, Owner, TemplateArgs);
971  return Instantiator.Visit(D);
972}
973
974/// \brief Instantiates a nested template parameter list in the current
975/// instantiation context.
976///
977/// \param L The parameter list to instantiate
978///
979/// \returns NULL if there was an error
980TemplateParameterList *
981TemplateDeclInstantiator::SubstTemplateParams(TemplateParameterList *L) {
982  // Get errors for all the parameters before bailing out.
983  bool Invalid = false;
984
985  unsigned N = L->size();
986  typedef llvm::SmallVector<NamedDecl *, 8> ParamVector;
987  ParamVector Params;
988  Params.reserve(N);
989  for (TemplateParameterList::iterator PI = L->begin(), PE = L->end();
990       PI != PE; ++PI) {
991    NamedDecl *D = cast_or_null<NamedDecl>(Visit(*PI));
992    Params.push_back(D);
993    Invalid = Invalid || !D;
994  }
995
996  // Clean up if we had an error.
997  if (Invalid) {
998    for (ParamVector::iterator PI = Params.begin(), PE = Params.end();
999         PI != PE; ++PI)
1000      if (*PI)
1001        (*PI)->Destroy(SemaRef.Context);
1002    return NULL;
1003  }
1004
1005  TemplateParameterList *InstL
1006    = TemplateParameterList::Create(SemaRef.Context, L->getTemplateLoc(),
1007                                    L->getLAngleLoc(), &Params.front(), N,
1008                                    L->getRAngleLoc());
1009  return InstL;
1010}
1011
1012/// \brief Instantiate the declaration of a class template partial
1013/// specialization.
1014///
1015/// \param ClassTemplate the (instantiated) class template that is partially
1016// specialized by the instantiation of \p PartialSpec.
1017///
1018/// \param PartialSpec the (uninstantiated) class template partial
1019/// specialization that we are instantiating.
1020///
1021/// \returns true if there was an error, false otherwise.
1022bool
1023TemplateDeclInstantiator::InstantiateClassTemplatePartialSpecialization(
1024                                            ClassTemplateDecl *ClassTemplate,
1025                          ClassTemplatePartialSpecializationDecl *PartialSpec) {
1026  // Substitute into the template parameters of the class template partial
1027  // specialization.
1028  TemplateParameterList *TempParams = PartialSpec->getTemplateParameters();
1029  TemplateParameterList *InstParams = SubstTemplateParams(TempParams);
1030  if (!InstParams)
1031    return true;
1032
1033  // Substitute into the template arguments of the class template partial
1034  // specialization.
1035  const TemplateArgumentLoc *PartialSpecTemplateArgs
1036    = PartialSpec->getTemplateArgsAsWritten();
1037  unsigned N = PartialSpec->getNumTemplateArgsAsWritten();
1038
1039  llvm::SmallVector<TemplateArgumentLoc, 4> InstTemplateArgs(N);
1040  for (unsigned I = 0; I != N; ++I) {
1041    if (SemaRef.Subst(PartialSpecTemplateArgs[I], InstTemplateArgs[I],
1042                      TemplateArgs))
1043      return true;
1044  }
1045
1046
1047  // Check that the template argument list is well-formed for this
1048  // class template.
1049  TemplateArgumentListBuilder Converted(ClassTemplate->getTemplateParameters(),
1050                                        InstTemplateArgs.size());
1051  if (SemaRef.CheckTemplateArgumentList(ClassTemplate,
1052                                        PartialSpec->getLocation(),
1053                                        /*FIXME:*/PartialSpec->getLocation(),
1054                                        InstTemplateArgs.data(),
1055                                        InstTemplateArgs.size(),
1056                                        /*FIXME:*/PartialSpec->getLocation(),
1057                                        false,
1058                                        Converted))
1059    return true;
1060
1061  // Figure out where to insert this class template partial specialization
1062  // in the member template's set of class template partial specializations.
1063  llvm::FoldingSetNodeID ID;
1064  ClassTemplatePartialSpecializationDecl::Profile(ID,
1065                                                  Converted.getFlatArguments(),
1066                                                  Converted.flatSize(),
1067                                                  SemaRef.Context);
1068  void *InsertPos = 0;
1069  ClassTemplateSpecializationDecl *PrevDecl
1070    = ClassTemplate->getPartialSpecializations().FindNodeOrInsertPos(ID,
1071                                                                     InsertPos);
1072
1073  // Build the canonical type that describes the converted template
1074  // arguments of the class template partial specialization.
1075  QualType CanonType
1076    = SemaRef.Context.getTemplateSpecializationType(TemplateName(ClassTemplate),
1077                                                  Converted.getFlatArguments(),
1078                                                    Converted.flatSize());
1079
1080  // Build the fully-sugared type for this class template
1081  // specialization as the user wrote in the specialization
1082  // itself. This means that we'll pretty-print the type retrieved
1083  // from the specialization's declaration the way that the user
1084  // actually wrote the specialization, rather than formatting the
1085  // name based on the "canonical" representation used to store the
1086  // template arguments in the specialization.
1087  QualType WrittenTy
1088    = SemaRef.Context.getTemplateSpecializationType(TemplateName(ClassTemplate),
1089                                                    InstTemplateArgs.data(),
1090                                                    InstTemplateArgs.size(),
1091                                                    CanonType);
1092
1093  if (PrevDecl) {
1094    // We've already seen a partial specialization with the same template
1095    // parameters and template arguments. This can happen, for example, when
1096    // substituting the outer template arguments ends up causing two
1097    // class template partial specializations of a member class template
1098    // to have identical forms, e.g.,
1099    //
1100    //   template<typename T, typename U>
1101    //   struct Outer {
1102    //     template<typename X, typename Y> struct Inner;
1103    //     template<typename Y> struct Inner<T, Y>;
1104    //     template<typename Y> struct Inner<U, Y>;
1105    //   };
1106    //
1107    //   Outer<int, int> outer; // error: the partial specializations of Inner
1108    //                          // have the same signature.
1109    SemaRef.Diag(PartialSpec->getLocation(), diag::err_partial_spec_redeclared)
1110      << WrittenTy;
1111    SemaRef.Diag(PrevDecl->getLocation(), diag::note_prev_partial_spec_here)
1112      << SemaRef.Context.getTypeDeclType(PrevDecl);
1113    return true;
1114  }
1115
1116
1117  // Create the class template partial specialization declaration.
1118  ClassTemplatePartialSpecializationDecl *InstPartialSpec
1119    = ClassTemplatePartialSpecializationDecl::Create(SemaRef.Context, Owner,
1120                                                     PartialSpec->getLocation(),
1121                                                     InstParams,
1122                                                     ClassTemplate,
1123                                                     Converted,
1124                                                     InstTemplateArgs.data(),
1125                                                     InstTemplateArgs.size(),
1126                                                     0);
1127  InstPartialSpec->setInstantiatedFromMember(PartialSpec);
1128  InstPartialSpec->setTypeAsWritten(WrittenTy);
1129
1130  // Add this partial specialization to the set of class template partial
1131  // specializations.
1132  ClassTemplate->getPartialSpecializations().InsertNode(InstPartialSpec,
1133                                                        InsertPos);
1134  return false;
1135}
1136
1137/// \brief Does substitution on the type of the given function, including
1138/// all of the function parameters.
1139///
1140/// \param D The function whose type will be the basis of the substitution
1141///
1142/// \param Params the instantiated parameter declarations
1143
1144/// \returns the instantiated function's type if successful, a NULL
1145/// type if there was an error.
1146QualType
1147TemplateDeclInstantiator::SubstFunctionType(FunctionDecl *D,
1148                              llvm::SmallVectorImpl<ParmVarDecl *> &Params) {
1149  bool InvalidDecl = false;
1150
1151  // Substitute all of the function's formal parameter types.
1152  TemplateDeclInstantiator ParamInstantiator(SemaRef, 0, TemplateArgs);
1153  llvm::SmallVector<QualType, 4> ParamTys;
1154  for (FunctionDecl::param_iterator P = D->param_begin(),
1155                                 PEnd = D->param_end();
1156       P != PEnd; ++P) {
1157    if (ParmVarDecl *PInst = ParamInstantiator.VisitParmVarDecl(*P)) {
1158      if (PInst->getType()->isVoidType()) {
1159        SemaRef.Diag(PInst->getLocation(), diag::err_param_with_void_type);
1160        PInst->setInvalidDecl();
1161      } else if (SemaRef.RequireNonAbstractType(PInst->getLocation(),
1162                                                PInst->getType(),
1163                                                diag::err_abstract_type_in_decl,
1164                                                Sema::AbstractParamType))
1165        PInst->setInvalidDecl();
1166
1167      Params.push_back(PInst);
1168      ParamTys.push_back(PInst->getType());
1169
1170      if (PInst->isInvalidDecl())
1171        InvalidDecl = true;
1172    } else
1173      InvalidDecl = true;
1174  }
1175
1176  // FIXME: Deallocate dead declarations.
1177  if (InvalidDecl)
1178    return QualType();
1179
1180  const FunctionProtoType *Proto = D->getType()->getAs<FunctionProtoType>();
1181  assert(Proto && "Missing prototype?");
1182  QualType ResultType
1183    = SemaRef.SubstType(Proto->getResultType(), TemplateArgs,
1184                        D->getLocation(), D->getDeclName());
1185  if (ResultType.isNull())
1186    return QualType();
1187
1188  return SemaRef.BuildFunctionType(ResultType, ParamTys.data(), ParamTys.size(),
1189                                   Proto->isVariadic(), Proto->getTypeQuals(),
1190                                   D->getLocation(), D->getDeclName());
1191}
1192
1193/// \brief Initializes the common fields of an instantiation function
1194/// declaration (New) from the corresponding fields of its template (Tmpl).
1195///
1196/// \returns true if there was an error
1197bool
1198TemplateDeclInstantiator::InitFunctionInstantiation(FunctionDecl *New,
1199                                                    FunctionDecl *Tmpl) {
1200  if (Tmpl->isDeleted())
1201    New->setDeleted();
1202
1203  // If we are performing substituting explicitly-specified template arguments
1204  // or deduced template arguments into a function template and we reach this
1205  // point, we are now past the point where SFINAE applies and have committed
1206  // to keeping the new function template specialization. We therefore
1207  // convert the active template instantiation for the function template
1208  // into a template instantiation for this specific function template
1209  // specialization, which is not a SFINAE context, so that we diagnose any
1210  // further errors in the declaration itself.
1211  typedef Sema::ActiveTemplateInstantiation ActiveInstType;
1212  ActiveInstType &ActiveInst = SemaRef.ActiveTemplateInstantiations.back();
1213  if (ActiveInst.Kind == ActiveInstType::ExplicitTemplateArgumentSubstitution ||
1214      ActiveInst.Kind == ActiveInstType::DeducedTemplateArgumentSubstitution) {
1215    if (FunctionTemplateDecl *FunTmpl
1216          = dyn_cast<FunctionTemplateDecl>((Decl *)ActiveInst.Entity)) {
1217      assert(FunTmpl->getTemplatedDecl() == Tmpl &&
1218             "Deduction from the wrong function template?");
1219      (void) FunTmpl;
1220      ActiveInst.Kind = ActiveInstType::TemplateInstantiation;
1221      ActiveInst.Entity = reinterpret_cast<uintptr_t>(New);
1222    }
1223  }
1224
1225  return false;
1226}
1227
1228/// \brief Initializes common fields of an instantiated method
1229/// declaration (New) from the corresponding fields of its template
1230/// (Tmpl).
1231///
1232/// \returns true if there was an error
1233bool
1234TemplateDeclInstantiator::InitMethodInstantiation(CXXMethodDecl *New,
1235                                                  CXXMethodDecl *Tmpl) {
1236  if (InitFunctionInstantiation(New, Tmpl))
1237    return true;
1238
1239  CXXRecordDecl *Record = cast<CXXRecordDecl>(Owner);
1240  New->setAccess(Tmpl->getAccess());
1241  if (Tmpl->isVirtualAsWritten()) {
1242    New->setVirtualAsWritten(true);
1243    Record->setAggregate(false);
1244    Record->setPOD(false);
1245    Record->setEmpty(false);
1246    Record->setPolymorphic(true);
1247  }
1248  if (Tmpl->isPure()) {
1249    New->setPure();
1250    Record->setAbstract(true);
1251  }
1252
1253  // FIXME: attributes
1254  // FIXME: New needs a pointer to Tmpl
1255  return false;
1256}
1257
1258/// \brief Instantiate the definition of the given function from its
1259/// template.
1260///
1261/// \param PointOfInstantiation the point at which the instantiation was
1262/// required. Note that this is not precisely a "point of instantiation"
1263/// for the function, but it's close.
1264///
1265/// \param Function the already-instantiated declaration of a
1266/// function template specialization or member function of a class template
1267/// specialization.
1268///
1269/// \param Recursive if true, recursively instantiates any functions that
1270/// are required by this instantiation.
1271///
1272/// \param DefinitionRequired if true, then we are performing an explicit
1273/// instantiation where the body of the function is required. Complain if
1274/// there is no such body.
1275void Sema::InstantiateFunctionDefinition(SourceLocation PointOfInstantiation,
1276                                         FunctionDecl *Function,
1277                                         bool Recursive,
1278                                         bool DefinitionRequired) {
1279  if (Function->isInvalidDecl())
1280    return;
1281
1282  assert(!Function->getBody() && "Already instantiated!");
1283
1284  // Never instantiate an explicit specialization.
1285  if (Function->getTemplateSpecializationKind() == TSK_ExplicitSpecialization)
1286    return;
1287
1288  // Find the function body that we'll be substituting.
1289  const FunctionDecl *PatternDecl = Function->getTemplateInstantiationPattern();
1290  Stmt *Pattern = 0;
1291  if (PatternDecl)
1292    Pattern = PatternDecl->getBody(PatternDecl);
1293
1294  if (!Pattern) {
1295    if (DefinitionRequired) {
1296      if (Function->getPrimaryTemplate())
1297        Diag(PointOfInstantiation,
1298             diag::err_explicit_instantiation_undefined_func_template)
1299          << Function->getPrimaryTemplate();
1300      else
1301        Diag(PointOfInstantiation,
1302             diag::err_explicit_instantiation_undefined_member)
1303          << 1 << Function->getDeclName() << Function->getDeclContext();
1304
1305      if (PatternDecl)
1306        Diag(PatternDecl->getLocation(),
1307             diag::note_explicit_instantiation_here);
1308    }
1309
1310    return;
1311  }
1312
1313  // C++0x [temp.explicit]p9:
1314  //   Except for inline functions, other explicit instantiation declarations
1315  //   have the effect of suppressing the implicit instantiation of the entity
1316  //   to which they refer.
1317  if (Function->getTemplateSpecializationKind()
1318        == TSK_ExplicitInstantiationDeclaration &&
1319      !PatternDecl->isInlined())
1320    return;
1321
1322  InstantiatingTemplate Inst(*this, PointOfInstantiation, Function);
1323  if (Inst)
1324    return;
1325
1326  // If we're performing recursive template instantiation, create our own
1327  // queue of pending implicit instantiations that we will instantiate later,
1328  // while we're still within our own instantiation context.
1329  std::deque<PendingImplicitInstantiation> SavedPendingImplicitInstantiations;
1330  if (Recursive)
1331    PendingImplicitInstantiations.swap(SavedPendingImplicitInstantiations);
1332
1333  ActOnStartOfFunctionDef(0, DeclPtrTy::make(Function));
1334
1335  // Introduce a new scope where local variable instantiations will be
1336  // recorded.
1337  LocalInstantiationScope Scope(*this);
1338
1339  // Introduce the instantiated function parameters into the local
1340  // instantiation scope.
1341  for (unsigned I = 0, N = PatternDecl->getNumParams(); I != N; ++I)
1342    Scope.InstantiatedLocal(PatternDecl->getParamDecl(I),
1343                            Function->getParamDecl(I));
1344
1345  // Enter the scope of this instantiation. We don't use
1346  // PushDeclContext because we don't have a scope.
1347  DeclContext *PreviousContext = CurContext;
1348  CurContext = Function;
1349
1350  MultiLevelTemplateArgumentList TemplateArgs =
1351    getTemplateInstantiationArgs(Function);
1352
1353  // If this is a constructor, instantiate the member initializers.
1354  if (const CXXConstructorDecl *Ctor =
1355        dyn_cast<CXXConstructorDecl>(PatternDecl)) {
1356    InstantiateMemInitializers(cast<CXXConstructorDecl>(Function), Ctor,
1357                               TemplateArgs);
1358  }
1359
1360  // Instantiate the function body.
1361  OwningStmtResult Body = SubstStmt(Pattern, TemplateArgs);
1362
1363  if (Body.isInvalid())
1364    Function->setInvalidDecl();
1365
1366  ActOnFinishFunctionBody(DeclPtrTy::make(Function), move(Body),
1367                          /*IsInstantiation=*/true);
1368
1369  CurContext = PreviousContext;
1370
1371  DeclGroupRef DG(Function);
1372  Consumer.HandleTopLevelDecl(DG);
1373
1374  if (Recursive) {
1375    // Instantiate any pending implicit instantiations found during the
1376    // instantiation of this template.
1377    PerformPendingImplicitInstantiations();
1378
1379    // Restore the set of pending implicit instantiations.
1380    PendingImplicitInstantiations.swap(SavedPendingImplicitInstantiations);
1381  }
1382}
1383
1384/// \brief Instantiate the definition of the given variable from its
1385/// template.
1386///
1387/// \param PointOfInstantiation the point at which the instantiation was
1388/// required. Note that this is not precisely a "point of instantiation"
1389/// for the function, but it's close.
1390///
1391/// \param Var the already-instantiated declaration of a static member
1392/// variable of a class template specialization.
1393///
1394/// \param Recursive if true, recursively instantiates any functions that
1395/// are required by this instantiation.
1396///
1397/// \param DefinitionRequired if true, then we are performing an explicit
1398/// instantiation where an out-of-line definition of the member variable
1399/// is required. Complain if there is no such definition.
1400void Sema::InstantiateStaticDataMemberDefinition(
1401                                          SourceLocation PointOfInstantiation,
1402                                                 VarDecl *Var,
1403                                                 bool Recursive,
1404                                                 bool DefinitionRequired) {
1405  if (Var->isInvalidDecl())
1406    return;
1407
1408  // Find the out-of-line definition of this static data member.
1409  VarDecl *Def = Var->getInstantiatedFromStaticDataMember();
1410  assert(Def && "This data member was not instantiated from a template?");
1411  assert(Def->isStaticDataMember() && "Not a static data member?");
1412  Def = Def->getOutOfLineDefinition();
1413
1414  if (!Def) {
1415    // We did not find an out-of-line definition of this static data member,
1416    // so we won't perform any instantiation. Rather, we rely on the user to
1417    // instantiate this definition (or provide a specialization for it) in
1418    // another translation unit.
1419    if (DefinitionRequired) {
1420      Def = Var->getInstantiatedFromStaticDataMember();
1421      Diag(PointOfInstantiation,
1422           diag::err_explicit_instantiation_undefined_member)
1423        << 2 << Var->getDeclName() << Var->getDeclContext();
1424      Diag(Def->getLocation(), diag::note_explicit_instantiation_here);
1425    }
1426
1427    return;
1428  }
1429
1430  // Never instantiate an explicit specialization.
1431  if (Var->getTemplateSpecializationKind() == TSK_ExplicitSpecialization)
1432    return;
1433
1434  // C++0x [temp.explicit]p9:
1435  //   Except for inline functions, other explicit instantiation declarations
1436  //   have the effect of suppressing the implicit instantiation of the entity
1437  //   to which they refer.
1438  if (Var->getTemplateSpecializationKind()
1439        == TSK_ExplicitInstantiationDeclaration)
1440    return;
1441
1442  InstantiatingTemplate Inst(*this, PointOfInstantiation, Var);
1443  if (Inst)
1444    return;
1445
1446  // If we're performing recursive template instantiation, create our own
1447  // queue of pending implicit instantiations that we will instantiate later,
1448  // while we're still within our own instantiation context.
1449  std::deque<PendingImplicitInstantiation> SavedPendingImplicitInstantiations;
1450  if (Recursive)
1451    PendingImplicitInstantiations.swap(SavedPendingImplicitInstantiations);
1452
1453  // Enter the scope of this instantiation. We don't use
1454  // PushDeclContext because we don't have a scope.
1455  DeclContext *PreviousContext = CurContext;
1456  CurContext = Var->getDeclContext();
1457
1458  VarDecl *OldVar = Var;
1459  Var = cast_or_null<VarDecl>(SubstDecl(Def, Var->getDeclContext(),
1460                                          getTemplateInstantiationArgs(Var)));
1461  CurContext = PreviousContext;
1462
1463  if (Var) {
1464    Var->setPreviousDeclaration(OldVar);
1465    MemberSpecializationInfo *MSInfo = OldVar->getMemberSpecializationInfo();
1466    assert(MSInfo && "Missing member specialization information?");
1467    Var->setTemplateSpecializationKind(MSInfo->getTemplateSpecializationKind(),
1468                                       MSInfo->getPointOfInstantiation());
1469    DeclGroupRef DG(Var);
1470    Consumer.HandleTopLevelDecl(DG);
1471  }
1472
1473  if (Recursive) {
1474    // Instantiate any pending implicit instantiations found during the
1475    // instantiation of this template.
1476    PerformPendingImplicitInstantiations();
1477
1478    // Restore the set of pending implicit instantiations.
1479    PendingImplicitInstantiations.swap(SavedPendingImplicitInstantiations);
1480  }
1481}
1482
1483void
1484Sema::InstantiateMemInitializers(CXXConstructorDecl *New,
1485                                 const CXXConstructorDecl *Tmpl,
1486                           const MultiLevelTemplateArgumentList &TemplateArgs) {
1487
1488  llvm::SmallVector<MemInitTy*, 4> NewInits;
1489
1490  // Instantiate all the initializers.
1491  for (CXXConstructorDecl::init_const_iterator Inits = Tmpl->init_begin(),
1492                                            InitsEnd = Tmpl->init_end();
1493       Inits != InitsEnd; ++Inits) {
1494    CXXBaseOrMemberInitializer *Init = *Inits;
1495
1496    ASTOwningVector<&ActionBase::DeleteExpr> NewArgs(*this);
1497
1498    // Instantiate all the arguments.
1499    for (ExprIterator Args = Init->arg_begin(), ArgsEnd = Init->arg_end();
1500         Args != ArgsEnd; ++Args) {
1501      OwningExprResult NewArg = SubstExpr(*Args, TemplateArgs);
1502
1503      if (NewArg.isInvalid())
1504        New->setInvalidDecl();
1505      else
1506        NewArgs.push_back(NewArg.takeAs<Expr>());
1507    }
1508
1509    MemInitResult NewInit;
1510
1511    if (Init->isBaseInitializer()) {
1512      QualType BaseType(Init->getBaseClass(), 0);
1513      BaseType = SubstType(BaseType, TemplateArgs, Init->getSourceLocation(),
1514                           New->getDeclName());
1515
1516      NewInit = BuildBaseInitializer(BaseType,
1517                                     (Expr **)NewArgs.data(),
1518                                     NewArgs.size(),
1519                                     Init->getSourceLocation(),
1520                                     Init->getRParenLoc(),
1521                                     New->getParent());
1522    } else if (Init->isMemberInitializer()) {
1523      FieldDecl *Member;
1524
1525      // Is this an anonymous union?
1526      if (FieldDecl *UnionInit = Init->getAnonUnionMember())
1527        Member = cast<FieldDecl>(FindInstantiatedDecl(UnionInit, TemplateArgs));
1528      else
1529        Member = cast<FieldDecl>(FindInstantiatedDecl(Init->getMember(),
1530                                                      TemplateArgs));
1531
1532      NewInit = BuildMemberInitializer(Member, (Expr **)NewArgs.data(),
1533                                       NewArgs.size(),
1534                                       Init->getSourceLocation(),
1535                                       Init->getRParenLoc());
1536    }
1537
1538    if (NewInit.isInvalid())
1539      New->setInvalidDecl();
1540    else {
1541      // FIXME: It would be nice if ASTOwningVector had a release function.
1542      NewArgs.take();
1543
1544      NewInits.push_back((MemInitTy *)NewInit.get());
1545    }
1546  }
1547
1548  // Assign all the initializers to the new constructor.
1549  ActOnMemInitializers(DeclPtrTy::make(New),
1550                       /*FIXME: ColonLoc */
1551                       SourceLocation(),
1552                       NewInits.data(), NewInits.size());
1553}
1554
1555// TODO: this could be templated if the various decl types used the
1556// same method name.
1557static bool isInstantiationOf(ClassTemplateDecl *Pattern,
1558                              ClassTemplateDecl *Instance) {
1559  Pattern = Pattern->getCanonicalDecl();
1560
1561  do {
1562    Instance = Instance->getCanonicalDecl();
1563    if (Pattern == Instance) return true;
1564    Instance = Instance->getInstantiatedFromMemberTemplate();
1565  } while (Instance);
1566
1567  return false;
1568}
1569
1570static bool isInstantiationOf(FunctionTemplateDecl *Pattern,
1571                              FunctionTemplateDecl *Instance) {
1572  Pattern = Pattern->getCanonicalDecl();
1573
1574  do {
1575    Instance = Instance->getCanonicalDecl();
1576    if (Pattern == Instance) return true;
1577    Instance = Instance->getInstantiatedFromMemberTemplate();
1578  } while (Instance);
1579
1580  return false;
1581}
1582
1583static bool
1584isInstantiationOf(ClassTemplatePartialSpecializationDecl *Pattern,
1585                  ClassTemplatePartialSpecializationDecl *Instance) {
1586  Pattern
1587    = cast<ClassTemplatePartialSpecializationDecl>(Pattern->getCanonicalDecl());
1588  do {
1589    Instance = cast<ClassTemplatePartialSpecializationDecl>(
1590                                                Instance->getCanonicalDecl());
1591    if (Pattern == Instance)
1592      return true;
1593    Instance = Instance->getInstantiatedFromMember();
1594  } while (Instance);
1595
1596  return false;
1597}
1598
1599static bool isInstantiationOf(CXXRecordDecl *Pattern,
1600                              CXXRecordDecl *Instance) {
1601  Pattern = Pattern->getCanonicalDecl();
1602
1603  do {
1604    Instance = Instance->getCanonicalDecl();
1605    if (Pattern == Instance) return true;
1606    Instance = Instance->getInstantiatedFromMemberClass();
1607  } while (Instance);
1608
1609  return false;
1610}
1611
1612static bool isInstantiationOf(FunctionDecl *Pattern,
1613                              FunctionDecl *Instance) {
1614  Pattern = Pattern->getCanonicalDecl();
1615
1616  do {
1617    Instance = Instance->getCanonicalDecl();
1618    if (Pattern == Instance) return true;
1619    Instance = Instance->getInstantiatedFromMemberFunction();
1620  } while (Instance);
1621
1622  return false;
1623}
1624
1625static bool isInstantiationOf(EnumDecl *Pattern,
1626                              EnumDecl *Instance) {
1627  Pattern = Pattern->getCanonicalDecl();
1628
1629  do {
1630    Instance = Instance->getCanonicalDecl();
1631    if (Pattern == Instance) return true;
1632    Instance = Instance->getInstantiatedFromMemberEnum();
1633  } while (Instance);
1634
1635  return false;
1636}
1637
1638static bool isInstantiationOf(UnresolvedUsingDecl *Pattern,
1639                              UsingDecl *Instance,
1640                              ASTContext &C) {
1641  return C.getInstantiatedFromUnresolvedUsingDecl(Instance) == Pattern;
1642}
1643
1644static bool isInstantiationOfStaticDataMember(VarDecl *Pattern,
1645                                              VarDecl *Instance) {
1646  assert(Instance->isStaticDataMember());
1647
1648  Pattern = Pattern->getCanonicalDecl();
1649
1650  do {
1651    Instance = Instance->getCanonicalDecl();
1652    if (Pattern == Instance) return true;
1653    Instance = Instance->getInstantiatedFromStaticDataMember();
1654  } while (Instance);
1655
1656  return false;
1657}
1658
1659static bool isInstantiationOf(ASTContext &Ctx, NamedDecl *D, Decl *Other) {
1660  if (D->getKind() != Other->getKind()) {
1661    if (UnresolvedUsingDecl *UUD = dyn_cast<UnresolvedUsingDecl>(D)) {
1662      if (UsingDecl *UD = dyn_cast<UsingDecl>(Other)) {
1663        return isInstantiationOf(UUD, UD, Ctx);
1664      }
1665    }
1666
1667    return false;
1668  }
1669
1670  if (CXXRecordDecl *Record = dyn_cast<CXXRecordDecl>(Other))
1671    return isInstantiationOf(cast<CXXRecordDecl>(D), Record);
1672
1673  if (FunctionDecl *Function = dyn_cast<FunctionDecl>(Other))
1674    return isInstantiationOf(cast<FunctionDecl>(D), Function);
1675
1676  if (EnumDecl *Enum = dyn_cast<EnumDecl>(Other))
1677    return isInstantiationOf(cast<EnumDecl>(D), Enum);
1678
1679  if (VarDecl *Var = dyn_cast<VarDecl>(Other))
1680    if (Var->isStaticDataMember())
1681      return isInstantiationOfStaticDataMember(cast<VarDecl>(D), Var);
1682
1683  if (ClassTemplateDecl *Temp = dyn_cast<ClassTemplateDecl>(Other))
1684    return isInstantiationOf(cast<ClassTemplateDecl>(D), Temp);
1685
1686  if (FunctionTemplateDecl *Temp = dyn_cast<FunctionTemplateDecl>(Other))
1687    return isInstantiationOf(cast<FunctionTemplateDecl>(D), Temp);
1688
1689  if (ClassTemplatePartialSpecializationDecl *PartialSpec
1690        = dyn_cast<ClassTemplatePartialSpecializationDecl>(Other))
1691    return isInstantiationOf(cast<ClassTemplatePartialSpecializationDecl>(D),
1692                             PartialSpec);
1693
1694  if (FieldDecl *Field = dyn_cast<FieldDecl>(Other)) {
1695    if (!Field->getDeclName()) {
1696      // This is an unnamed field.
1697      return Ctx.getInstantiatedFromUnnamedFieldDecl(Field) ==
1698        cast<FieldDecl>(D);
1699    }
1700  }
1701
1702  return D->getDeclName() && isa<NamedDecl>(Other) &&
1703    D->getDeclName() == cast<NamedDecl>(Other)->getDeclName();
1704}
1705
1706template<typename ForwardIterator>
1707static NamedDecl *findInstantiationOf(ASTContext &Ctx,
1708                                      NamedDecl *D,
1709                                      ForwardIterator first,
1710                                      ForwardIterator last) {
1711  for (; first != last; ++first)
1712    if (isInstantiationOf(Ctx, D, *first))
1713      return cast<NamedDecl>(*first);
1714
1715  return 0;
1716}
1717
1718/// \brief Finds the instantiation of the given declaration context
1719/// within the current instantiation.
1720///
1721/// \returns NULL if there was an error
1722DeclContext *Sema::FindInstantiatedContext(DeclContext* DC,
1723                          const MultiLevelTemplateArgumentList &TemplateArgs) {
1724  if (NamedDecl *D = dyn_cast<NamedDecl>(DC)) {
1725    Decl* ID = FindInstantiatedDecl(D, TemplateArgs);
1726    return cast_or_null<DeclContext>(ID);
1727  } else return DC;
1728}
1729
1730/// \brief Find the instantiation of the given declaration within the
1731/// current instantiation.
1732///
1733/// This routine is intended to be used when \p D is a declaration
1734/// referenced from within a template, that needs to mapped into the
1735/// corresponding declaration within an instantiation. For example,
1736/// given:
1737///
1738/// \code
1739/// template<typename T>
1740/// struct X {
1741///   enum Kind {
1742///     KnownValue = sizeof(T)
1743///   };
1744///
1745///   bool getKind() const { return KnownValue; }
1746/// };
1747///
1748/// template struct X<int>;
1749/// \endcode
1750///
1751/// In the instantiation of X<int>::getKind(), we need to map the
1752/// EnumConstantDecl for KnownValue (which refers to
1753/// X<T>::<Kind>::KnownValue) to its instantiation
1754/// (X<int>::<Kind>::KnownValue). InstantiateCurrentDeclRef() performs
1755/// this mapping from within the instantiation of X<int>.
1756NamedDecl *Sema::FindInstantiatedDecl(NamedDecl *D,
1757                          const MultiLevelTemplateArgumentList &TemplateArgs) {
1758  if (OverloadedFunctionDecl *Ovl = dyn_cast<OverloadedFunctionDecl>(D)) {
1759    // Transform all of the elements of the overloaded function set.
1760    OverloadedFunctionDecl *Result
1761      = OverloadedFunctionDecl::Create(Context, CurContext, Ovl->getDeclName());
1762
1763    for (OverloadedFunctionDecl::function_iterator F = Ovl->function_begin(),
1764                                                FEnd = Ovl->function_end();
1765         F != FEnd; ++F) {
1766      Result->addOverload(
1767        AnyFunctionDecl::getFromNamedDecl(FindInstantiatedDecl(*F,
1768                                                               TemplateArgs)));
1769    }
1770
1771    return Result;
1772  }
1773
1774  DeclContext *ParentDC = D->getDeclContext();
1775  if (isa<ParmVarDecl>(D) || ParentDC->isFunctionOrMethod()) {
1776    // D is a local of some kind. Look into the map of local
1777    // declarations to their instantiations.
1778    return cast<NamedDecl>(CurrentInstantiationScope->getInstantiationOf(D));
1779  }
1780
1781  if (CXXRecordDecl *Record = dyn_cast<CXXRecordDecl>(D)) {
1782    if (!Record->isDependentContext())
1783      return D;
1784
1785    // If the RecordDecl is actually the injected-class-name or a "templated"
1786    // declaration for a class template or class template partial
1787    // specialization, substitute into the injected-class-name of the
1788    // class template or partial specialization to find the new DeclContext.
1789    QualType T;
1790    ClassTemplateDecl *ClassTemplate = Record->getDescribedClassTemplate();
1791
1792    if (ClassTemplate) {
1793      T = ClassTemplate->getInjectedClassNameType(Context);
1794    } else if (ClassTemplatePartialSpecializationDecl *PartialSpec
1795                 = dyn_cast<ClassTemplatePartialSpecializationDecl>(Record)) {
1796      T = Context.getTypeDeclType(Record);
1797      ClassTemplate = PartialSpec->getSpecializedTemplate();
1798    }
1799
1800    if (!T.isNull()) {
1801      // Substitute into the injected-class-name to get the type corresponding
1802      // to the instantiation we want. This substitution should never fail,
1803      // since we know we can instantiate the injected-class-name or we wouldn't
1804      // have gotten to the injected-class-name!
1805      // FIXME: Can we use the CurrentInstantiationScope to avoid this extra
1806      // instantiation in the common case?
1807      T = SubstType(T, TemplateArgs, SourceLocation(), DeclarationName());
1808      assert(!T.isNull() && "Instantiation of injected-class-name cannot fail.");
1809
1810      if (!T->isDependentType()) {
1811        assert(T->isRecordType() && "Instantiation must produce a record type");
1812        return T->getAs<RecordType>()->getDecl();
1813      }
1814
1815      // We are performing "partial" template instantiation to create the
1816      // member declarations for the members of a class template
1817      // specialization. Therefore, D is actually referring to something in
1818      // the current instantiation. Look through the current context,
1819      // which contains actual instantiations, to find the instantiation of
1820      // the "current instantiation" that D refers to.
1821      for (DeclContext *DC = CurContext; !DC->isFileContext();
1822           DC = DC->getParent()) {
1823        if (ClassTemplateSpecializationDecl *Spec
1824              = dyn_cast<ClassTemplateSpecializationDecl>(DC))
1825          if (isInstantiationOf(ClassTemplate,
1826                                Spec->getSpecializedTemplate()))
1827            return Spec;
1828      }
1829
1830      assert(false &&
1831             "Unable to find declaration for the current instantiation");
1832      return Record;
1833    }
1834
1835    // Fall through to deal with other dependent record types (e.g.,
1836    // anonymous unions in class templates).
1837  }
1838
1839  if (!ParentDC->isDependentContext())
1840    return D;
1841
1842  ParentDC = FindInstantiatedContext(ParentDC, TemplateArgs);
1843  if (!ParentDC)
1844    return 0;
1845
1846  if (ParentDC != D->getDeclContext()) {
1847    // We performed some kind of instantiation in the parent context,
1848    // so now we need to look into the instantiated parent context to
1849    // find the instantiation of the declaration D.
1850    NamedDecl *Result = 0;
1851    if (D->getDeclName()) {
1852      DeclContext::lookup_result Found = ParentDC->lookup(D->getDeclName());
1853      Result = findInstantiationOf(Context, D, Found.first, Found.second);
1854    } else {
1855      // Since we don't have a name for the entity we're looking for,
1856      // our only option is to walk through all of the declarations to
1857      // find that name. This will occur in a few cases:
1858      //
1859      //   - anonymous struct/union within a template
1860      //   - unnamed class/struct/union/enum within a template
1861      //
1862      // FIXME: Find a better way to find these instantiations!
1863      Result = findInstantiationOf(Context, D,
1864                                   ParentDC->decls_begin(),
1865                                   ParentDC->decls_end());
1866    }
1867
1868    assert(Result && "Unable to find instantiation of declaration!");
1869    D = Result;
1870  }
1871
1872  return D;
1873}
1874
1875/// \brief Performs template instantiation for all implicit template
1876/// instantiations we have seen until this point.
1877void Sema::PerformPendingImplicitInstantiations() {
1878  while (!PendingImplicitInstantiations.empty()) {
1879    PendingImplicitInstantiation Inst = PendingImplicitInstantiations.front();
1880    PendingImplicitInstantiations.pop_front();
1881
1882    // Instantiate function definitions
1883    if (FunctionDecl *Function = dyn_cast<FunctionDecl>(Inst.first)) {
1884      PrettyStackTraceActionsDecl CrashInfo(DeclPtrTy::make(Function),
1885                                            Function->getLocation(), *this,
1886                                            Context.getSourceManager(),
1887                                           "instantiating function definition");
1888
1889      if (!Function->getBody())
1890        InstantiateFunctionDefinition(/*FIXME:*/Inst.second, Function, true);
1891      continue;
1892    }
1893
1894    // Instantiate static data member definitions.
1895    VarDecl *Var = cast<VarDecl>(Inst.first);
1896    assert(Var->isStaticDataMember() && "Not a static data member?");
1897
1898    PrettyStackTraceActionsDecl CrashInfo(DeclPtrTy::make(Var),
1899                                          Var->getLocation(), *this,
1900                                          Context.getSourceManager(),
1901                                          "instantiating static data member "
1902                                          "definition");
1903
1904    InstantiateStaticDataMemberDefinition(/*FIXME:*/Inst.second, Var, true);
1905  }
1906}
1907