SemaTemplateInstantiateDecl.cpp revision f88b0d6c99e6473e78331271935986535dc4603c 
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 "Lookup.h"
14#include "clang/AST/ASTConsumer.h"
15#include "clang/AST/ASTContext.h"
16#include "clang/AST/DeclTemplate.h"
17#include "clang/AST/DeclVisitor.h"
18#include "clang/AST/DependentDiagnostic.h"
19#include "clang/AST/Expr.h"
20#include "clang/AST/ExprCXX.h"
21#include "clang/AST/TypeLoc.h"
22#include "clang/Basic/PrettyStackTrace.h"
23#include "clang/Lex/Preprocessor.h"
24
25using namespace clang;
26
27namespace {
28  class TemplateDeclInstantiator
29    : public DeclVisitor<TemplateDeclInstantiator, Decl *> {
30    Sema &SemaRef;
31    DeclContext *Owner;
32    const MultiLevelTemplateArgumentList &TemplateArgs;
33
34    void InstantiateAttrs(Decl *Tmpl, Decl *New);
35
36  public:
37    typedef Sema::OwningExprResult OwningExprResult;
38
39    TemplateDeclInstantiator(Sema &SemaRef, DeclContext *Owner,
40                             const MultiLevelTemplateArgumentList &TemplateArgs)
41      : SemaRef(SemaRef), Owner(Owner), TemplateArgs(TemplateArgs) { }
42
43    // FIXME: Once we get closer to completion, replace these manually-written
44    // declarations with automatically-generated ones from
45    // clang/AST/DeclNodes.def.
46    Decl *VisitTranslationUnitDecl(TranslationUnitDecl *D);
47    Decl *VisitNamespaceDecl(NamespaceDecl *D);
48    Decl *VisitNamespaceAliasDecl(NamespaceAliasDecl *D);
49    Decl *VisitTypedefDecl(TypedefDecl *D);
50    Decl *VisitVarDecl(VarDecl *D);
51    Decl *VisitFieldDecl(FieldDecl *D);
52    Decl *VisitStaticAssertDecl(StaticAssertDecl *D);
53    Decl *VisitEnumDecl(EnumDecl *D);
54    Decl *VisitEnumConstantDecl(EnumConstantDecl *D);
55    Decl *VisitFriendDecl(FriendDecl *D);
56    Decl *VisitFunctionDecl(FunctionDecl *D,
57                            TemplateParameterList *TemplateParams = 0);
58    Decl *VisitCXXRecordDecl(CXXRecordDecl *D);
59    Decl *VisitCXXMethodDecl(CXXMethodDecl *D,
60                             TemplateParameterList *TemplateParams = 0);
61    Decl *VisitCXXConstructorDecl(CXXConstructorDecl *D);
62    Decl *VisitCXXDestructorDecl(CXXDestructorDecl *D);
63    Decl *VisitCXXConversionDecl(CXXConversionDecl *D);
64    ParmVarDecl *VisitParmVarDecl(ParmVarDecl *D);
65    Decl *VisitClassTemplateDecl(ClassTemplateDecl *D);
66    Decl *VisitClassTemplatePartialSpecializationDecl(
67                                    ClassTemplatePartialSpecializationDecl *D);
68    Decl *VisitFunctionTemplateDecl(FunctionTemplateDecl *D);
69    Decl *VisitTemplateTypeParmDecl(TemplateTypeParmDecl *D);
70    Decl *VisitNonTypeTemplateParmDecl(NonTypeTemplateParmDecl *D);
71    Decl *VisitTemplateTemplateParmDecl(TemplateTemplateParmDecl *D);
72    Decl *VisitUsingDirectiveDecl(UsingDirectiveDecl *D);
73    Decl *VisitUsingDecl(UsingDecl *D);
74    Decl *VisitUsingShadowDecl(UsingShadowDecl *D);
75    Decl *VisitUnresolvedUsingValueDecl(UnresolvedUsingValueDecl *D);
76    Decl *VisitUnresolvedUsingTypenameDecl(UnresolvedUsingTypenameDecl *D);
77
78    // Base case. FIXME: Remove once we can instantiate everything.
79    Decl *VisitDecl(Decl *D) {
80      unsigned DiagID = SemaRef.getDiagnostics().getCustomDiagID(
81                                                            Diagnostic::Error,
82                                                   "cannot instantiate %0 yet");
83      SemaRef.Diag(D->getLocation(), DiagID)
84        << D->getDeclKindName();
85
86      return 0;
87    }
88
89    const LangOptions &getLangOptions() {
90      return SemaRef.getLangOptions();
91    }
92
93    // Helper functions for instantiating methods.
94    TypeSourceInfo *SubstFunctionType(FunctionDecl *D,
95                             llvm::SmallVectorImpl<ParmVarDecl *> &Params);
96    bool InitFunctionInstantiation(FunctionDecl *New, FunctionDecl *Tmpl);
97    bool InitMethodInstantiation(CXXMethodDecl *New, CXXMethodDecl *Tmpl);
98
99    TemplateParameterList *
100      SubstTemplateParams(TemplateParameterList *List);
101
102    bool SubstQualifier(const DeclaratorDecl *OldDecl,
103                        DeclaratorDecl *NewDecl);
104    bool SubstQualifier(const TagDecl *OldDecl,
105                        TagDecl *NewDecl);
106
107    bool InstantiateClassTemplatePartialSpecialization(
108                                              ClassTemplateDecl *ClassTemplate,
109                           ClassTemplatePartialSpecializationDecl *PartialSpec);
110  };
111}
112
113bool TemplateDeclInstantiator::SubstQualifier(const DeclaratorDecl *OldDecl,
114                                              DeclaratorDecl *NewDecl) {
115  NestedNameSpecifier *OldQual = OldDecl->getQualifier();
116  if (!OldQual) return false;
117
118  SourceRange QualRange = OldDecl->getQualifierRange();
119
120  NestedNameSpecifier *NewQual
121    = SemaRef.SubstNestedNameSpecifier(OldQual, QualRange, TemplateArgs);
122  if (!NewQual)
123    return true;
124
125  NewDecl->setQualifierInfo(NewQual, QualRange);
126  return false;
127}
128
129bool TemplateDeclInstantiator::SubstQualifier(const TagDecl *OldDecl,
130                                              TagDecl *NewDecl) {
131  NestedNameSpecifier *OldQual = OldDecl->getQualifier();
132  if (!OldQual) return false;
133
134  SourceRange QualRange = OldDecl->getQualifierRange();
135
136  NestedNameSpecifier *NewQual
137    = SemaRef.SubstNestedNameSpecifier(OldQual, QualRange, TemplateArgs);
138  if (!NewQual)
139    return true;
140
141  NewDecl->setQualifierInfo(NewQual, QualRange);
142  return false;
143}
144
145// FIXME: Is this too simple?
146void TemplateDeclInstantiator::InstantiateAttrs(Decl *Tmpl, Decl *New) {
147  for (const Attr *TmplAttr = Tmpl->getAttrs(); TmplAttr;
148       TmplAttr = TmplAttr->getNext()) {
149
150    // FIXME: Is cloning correct for all attributes?
151    Attr *NewAttr = TmplAttr->clone(SemaRef.Context);
152
153    New->addAttr(NewAttr);
154  }
155}
156
157Decl *
158TemplateDeclInstantiator::VisitTranslationUnitDecl(TranslationUnitDecl *D) {
159  assert(false && "Translation units cannot be instantiated");
160  return D;
161}
162
163Decl *
164TemplateDeclInstantiator::VisitNamespaceDecl(NamespaceDecl *D) {
165  assert(false && "Namespaces cannot be instantiated");
166  return D;
167}
168
169Decl *
170TemplateDeclInstantiator::VisitNamespaceAliasDecl(NamespaceAliasDecl *D) {
171  NamespaceAliasDecl *Inst
172    = NamespaceAliasDecl::Create(SemaRef.Context, Owner,
173                                 D->getNamespaceLoc(),
174                                 D->getAliasLoc(),
175                                 D->getNamespace()->getIdentifier(),
176                                 D->getQualifierRange(),
177                                 D->getQualifier(),
178                                 D->getTargetNameLoc(),
179                                 D->getNamespace());
180  Owner->addDecl(Inst);
181  return Inst;
182}
183
184Decl *TemplateDeclInstantiator::VisitTypedefDecl(TypedefDecl *D) {
185  bool Invalid = false;
186  TypeSourceInfo *DI = D->getTypeSourceInfo();
187  if (DI->getType()->isDependentType()) {
188    DI = SemaRef.SubstType(DI, TemplateArgs,
189                           D->getLocation(), D->getDeclName());
190    if (!DI) {
191      Invalid = true;
192      DI = SemaRef.Context.getTrivialTypeSourceInfo(SemaRef.Context.IntTy);
193    }
194  }
195
196  // Create the new typedef
197  TypedefDecl *Typedef
198    = TypedefDecl::Create(SemaRef.Context, Owner, D->getLocation(),
199                          D->getIdentifier(), DI);
200  if (Invalid)
201    Typedef->setInvalidDecl();
202
203  if (const TagType *TT = DI->getType()->getAs<TagType>()) {
204    TagDecl *TD = TT->getDecl();
205
206    // If the TagDecl that the TypedefDecl points to is an anonymous decl
207    // keep track of the TypedefDecl.
208    if (!TD->getIdentifier() && !TD->getTypedefForAnonDecl())
209      TD->setTypedefForAnonDecl(Typedef);
210  }
211
212  if (TypedefDecl *Prev = D->getPreviousDeclaration()) {
213    NamedDecl *InstPrev = SemaRef.FindInstantiatedDecl(D->getLocation(), Prev,
214                                                       TemplateArgs);
215    Typedef->setPreviousDeclaration(cast<TypedefDecl>(InstPrev));
216  }
217
218
219  Typedef->setAccess(D->getAccess());
220  Owner->addDecl(Typedef);
221
222  return Typedef;
223}
224
225/// \brief Instantiate the arguments provided as part of initialization.
226///
227/// \returns true if an error occurred, false otherwise.
228static bool InstantiateInitializationArguments(Sema &SemaRef,
229                                               Expr **Args, unsigned NumArgs,
230                           const MultiLevelTemplateArgumentList &TemplateArgs,
231                         llvm::SmallVectorImpl<SourceLocation> &FakeCommaLocs,
232                           ASTOwningVector<&ActionBase::DeleteExpr> &InitArgs) {
233  for (unsigned I = 0; I != NumArgs; ++I) {
234    // When we hit the first defaulted argument, break out of the loop:
235    // we don't pass those default arguments on.
236    if (Args[I]->isDefaultArgument())
237      break;
238
239    Sema::OwningExprResult Arg = SemaRef.SubstExpr(Args[I], TemplateArgs);
240    if (Arg.isInvalid())
241      return true;
242
243    Expr *ArgExpr = (Expr *)Arg.get();
244    InitArgs.push_back(Arg.release());
245
246    // FIXME: We're faking all of the comma locations. Do we need them?
247    FakeCommaLocs.push_back(
248                          SemaRef.PP.getLocForEndOfToken(ArgExpr->getLocEnd()));
249  }
250
251  return false;
252}
253
254/// \brief Instantiate an initializer, breaking it into separate
255/// initialization arguments.
256///
257/// \param S The semantic analysis object.
258///
259/// \param Init The initializer to instantiate.
260///
261/// \param TemplateArgs Template arguments to be substituted into the
262/// initializer.
263///
264/// \param NewArgs Will be filled in with the instantiation arguments.
265///
266/// \returns true if an error occurred, false otherwise
267static bool InstantiateInitializer(Sema &S, Expr *Init,
268                            const MultiLevelTemplateArgumentList &TemplateArgs,
269                                   SourceLocation &LParenLoc,
270                               llvm::SmallVector<SourceLocation, 4> &CommaLocs,
271                             ASTOwningVector<&ActionBase::DeleteExpr> &NewArgs,
272                                   SourceLocation &RParenLoc) {
273  NewArgs.clear();
274  LParenLoc = SourceLocation();
275  RParenLoc = SourceLocation();
276
277  if (!Init)
278    return false;
279
280  if (CXXExprWithTemporaries *ExprTemp = dyn_cast<CXXExprWithTemporaries>(Init))
281    Init = ExprTemp->getSubExpr();
282
283  while (CXXBindTemporaryExpr *Binder = dyn_cast<CXXBindTemporaryExpr>(Init))
284    Init = Binder->getSubExpr();
285
286  if (ImplicitCastExpr *ICE = dyn_cast<ImplicitCastExpr>(Init))
287    Init = ICE->getSubExprAsWritten();
288
289  if (ParenListExpr *ParenList = dyn_cast<ParenListExpr>(Init)) {
290    LParenLoc = ParenList->getLParenLoc();
291    RParenLoc = ParenList->getRParenLoc();
292    return InstantiateInitializationArguments(S, ParenList->getExprs(),
293                                              ParenList->getNumExprs(),
294                                              TemplateArgs, CommaLocs,
295                                              NewArgs);
296  }
297
298  if (CXXConstructExpr *Construct = dyn_cast<CXXConstructExpr>(Init)) {
299    if (!isa<CXXTemporaryObjectExpr>(Construct)) {
300      if (InstantiateInitializationArguments(S,
301                                             Construct->getArgs(),
302                                             Construct->getNumArgs(),
303                                             TemplateArgs,
304                                             CommaLocs, NewArgs))
305        return true;
306
307      // FIXME: Fake locations!
308      LParenLoc = S.PP.getLocForEndOfToken(Init->getLocStart());
309      RParenLoc = CommaLocs.empty()? LParenLoc : CommaLocs.back();
310      return false;
311    }
312  }
313
314  Sema::OwningExprResult Result = S.SubstExpr(Init, TemplateArgs);
315  if (Result.isInvalid())
316    return true;
317
318  NewArgs.push_back(Result.takeAs<Expr>());
319  return false;
320}
321
322Decl *TemplateDeclInstantiator::VisitVarDecl(VarDecl *D) {
323  // Do substitution on the type of the declaration
324  TypeSourceInfo *DI = SemaRef.SubstType(D->getTypeSourceInfo(),
325                                         TemplateArgs,
326                                         D->getTypeSpecStartLoc(),
327                                         D->getDeclName());
328  if (!DI)
329    return 0;
330
331  // Build the instantiated declaration
332  VarDecl *Var = VarDecl::Create(SemaRef.Context, Owner,
333                                 D->getLocation(), D->getIdentifier(),
334                                 DI->getType(), DI,
335                                 D->getStorageClass(),
336                                 D->getStorageClassAsWritten());
337  Var->setThreadSpecified(D->isThreadSpecified());
338  Var->setCXXDirectInitializer(D->hasCXXDirectInitializer());
339  Var->setDeclaredInCondition(D->isDeclaredInCondition());
340
341  // Substitute the nested name specifier, if any.
342  if (SubstQualifier(D, Var))
343    return 0;
344
345  // If we are instantiating a static data member defined
346  // out-of-line, the instantiation will have the same lexical
347  // context (which will be a namespace scope) as the template.
348  if (D->isOutOfLine())
349    Var->setLexicalDeclContext(D->getLexicalDeclContext());
350
351  Var->setAccess(D->getAccess());
352
353  // FIXME: In theory, we could have a previous declaration for variables that
354  // are not static data members.
355  bool Redeclaration = false;
356  // FIXME: having to fake up a LookupResult is dumb.
357  LookupResult Previous(SemaRef, Var->getDeclName(), Var->getLocation(),
358                        Sema::LookupOrdinaryName, Sema::ForRedeclaration);
359  if (D->isStaticDataMember())
360    SemaRef.LookupQualifiedName(Previous, Owner, false);
361  SemaRef.CheckVariableDeclaration(Var, Previous, Redeclaration);
362
363  if (D->isOutOfLine()) {
364    D->getLexicalDeclContext()->addDecl(Var);
365    Owner->makeDeclVisibleInContext(Var);
366  } else {
367    Owner->addDecl(Var);
368  }
369
370  // Link instantiations of static data members back to the template from
371  // which they were instantiated.
372  if (Var->isStaticDataMember())
373    SemaRef.Context.setInstantiatedFromStaticDataMember(Var, D,
374                                                     TSK_ImplicitInstantiation);
375
376  if (Var->getAnyInitializer()) {
377    // We already have an initializer in the class.
378  } else if (D->getInit()) {
379    if (Var->isStaticDataMember() && !D->isOutOfLine())
380      SemaRef.PushExpressionEvaluationContext(Sema::Unevaluated);
381    else
382      SemaRef.PushExpressionEvaluationContext(Sema::PotentiallyEvaluated);
383
384    // Instantiate the initializer.
385    SourceLocation LParenLoc, RParenLoc;
386    llvm::SmallVector<SourceLocation, 4> CommaLocs;
387    ASTOwningVector<&ActionBase::DeleteExpr> InitArgs(SemaRef);
388    if (!InstantiateInitializer(SemaRef, D->getInit(), TemplateArgs, LParenLoc,
389                                CommaLocs, InitArgs, RParenLoc)) {
390      // Attach the initializer to the declaration.
391      if (D->hasCXXDirectInitializer()) {
392        // Add the direct initializer to the declaration.
393        SemaRef.AddCXXDirectInitializerToDecl(Sema::DeclPtrTy::make(Var),
394                                              LParenLoc,
395                                              move_arg(InitArgs),
396                                              CommaLocs.data(),
397                                              RParenLoc);
398      } else if (InitArgs.size() == 1) {
399        Expr *Init = (Expr*)(InitArgs.take()[0]);
400        SemaRef.AddInitializerToDecl(Sema::DeclPtrTy::make(Var),
401                                     SemaRef.Owned(Init),
402                                     false);
403      } else {
404        assert(InitArgs.size() == 0);
405        SemaRef.ActOnUninitializedDecl(Sema::DeclPtrTy::make(Var), false);
406      }
407    } else {
408      // FIXME: Not too happy about invalidating the declaration
409      // because of a bogus initializer.
410      Var->setInvalidDecl();
411    }
412
413    SemaRef.PopExpressionEvaluationContext();
414  } else if (!Var->isStaticDataMember() || Var->isOutOfLine())
415    SemaRef.ActOnUninitializedDecl(Sema::DeclPtrTy::make(Var), false);
416
417  return Var;
418}
419
420Decl *TemplateDeclInstantiator::VisitFieldDecl(FieldDecl *D) {
421  bool Invalid = false;
422  TypeSourceInfo *DI = D->getTypeSourceInfo();
423  if (DI->getType()->isDependentType())  {
424    DI = SemaRef.SubstType(DI, TemplateArgs,
425                           D->getLocation(), D->getDeclName());
426    if (!DI) {
427      DI = D->getTypeSourceInfo();
428      Invalid = true;
429    } else if (DI->getType()->isFunctionType()) {
430      // C++ [temp.arg.type]p3:
431      //   If a declaration acquires a function type through a type
432      //   dependent on a template-parameter and this causes a
433      //   declaration that does not use the syntactic form of a
434      //   function declarator to have function type, the program is
435      //   ill-formed.
436      SemaRef.Diag(D->getLocation(), diag::err_field_instantiates_to_function)
437        << DI->getType();
438      Invalid = true;
439    }
440  }
441
442  Expr *BitWidth = D->getBitWidth();
443  if (Invalid)
444    BitWidth = 0;
445  else if (BitWidth) {
446    // The bit-width expression is not potentially evaluated.
447    EnterExpressionEvaluationContext Unevaluated(SemaRef, Action::Unevaluated);
448
449    OwningExprResult InstantiatedBitWidth
450      = SemaRef.SubstExpr(BitWidth, TemplateArgs);
451    if (InstantiatedBitWidth.isInvalid()) {
452      Invalid = true;
453      BitWidth = 0;
454    } else
455      BitWidth = InstantiatedBitWidth.takeAs<Expr>();
456  }
457
458  FieldDecl *Field = SemaRef.CheckFieldDecl(D->getDeclName(),
459                                            DI->getType(), DI,
460                                            cast<RecordDecl>(Owner),
461                                            D->getLocation(),
462                                            D->isMutable(),
463                                            BitWidth,
464                                            D->getTypeSpecStartLoc(),
465                                            D->getAccess(),
466                                            0);
467  if (!Field) {
468    cast<Decl>(Owner)->setInvalidDecl();
469    return 0;
470  }
471
472  InstantiateAttrs(D, Field);
473
474  if (Invalid)
475    Field->setInvalidDecl();
476
477  if (!Field->getDeclName()) {
478    // Keep track of where this decl came from.
479    SemaRef.Context.setInstantiatedFromUnnamedFieldDecl(Field, D);
480  }
481
482  Field->setImplicit(D->isImplicit());
483  Field->setAccess(D->getAccess());
484  Owner->addDecl(Field);
485
486  return Field;
487}
488
489Decl *TemplateDeclInstantiator::VisitFriendDecl(FriendDecl *D) {
490  // Handle friend type expressions by simply substituting template
491  // parameters into the pattern type and checking the result.
492  if (TypeSourceInfo *Ty = D->getFriendType()) {
493    TypeSourceInfo *InstTy =
494      SemaRef.SubstType(Ty, TemplateArgs,
495                        D->getLocation(), DeclarationName());
496    if (!InstTy)
497      return 0;
498
499    FriendDecl *FD = SemaRef.CheckFriendTypeDecl(D->getFriendLoc(), InstTy);
500    if (!FD)
501      return 0;
502
503    FD->setAccess(AS_public);
504    Owner->addDecl(FD);
505    return FD;
506  }
507
508  NamedDecl *ND = D->getFriendDecl();
509  assert(ND && "friend decl must be a decl or a type!");
510
511  // All of the Visit implementations for the various potential friend
512  // declarations have to be carefully written to work for friend
513  // objects, with the most important detail being that the target
514  // decl should almost certainly not be placed in Owner.
515  Decl *NewND = Visit(ND);
516  if (!NewND) return 0;
517
518  FriendDecl *FD =
519    FriendDecl::Create(SemaRef.Context, Owner, D->getLocation(),
520                       cast<NamedDecl>(NewND), D->getFriendLoc());
521  FD->setAccess(AS_public);
522  Owner->addDecl(FD);
523  return FD;
524}
525
526Decl *TemplateDeclInstantiator::VisitStaticAssertDecl(StaticAssertDecl *D) {
527  Expr *AssertExpr = D->getAssertExpr();
528
529  // The expression in a static assertion is not potentially evaluated.
530  EnterExpressionEvaluationContext Unevaluated(SemaRef, Action::Unevaluated);
531
532  OwningExprResult InstantiatedAssertExpr
533    = SemaRef.SubstExpr(AssertExpr, TemplateArgs);
534  if (InstantiatedAssertExpr.isInvalid())
535    return 0;
536
537  OwningExprResult Message(SemaRef, D->getMessage());
538  D->getMessage()->Retain();
539  Decl *StaticAssert
540    = SemaRef.ActOnStaticAssertDeclaration(D->getLocation(),
541                                           move(InstantiatedAssertExpr),
542                                           move(Message)).getAs<Decl>();
543  return StaticAssert;
544}
545
546Decl *TemplateDeclInstantiator::VisitEnumDecl(EnumDecl *D) {
547  EnumDecl *Enum = EnumDecl::Create(SemaRef.Context, Owner,
548                                    D->getLocation(), D->getIdentifier(),
549                                    D->getTagKeywordLoc(),
550                                    /*PrevDecl=*/0);
551  Enum->setInstantiationOfMemberEnum(D);
552  Enum->setAccess(D->getAccess());
553  if (SubstQualifier(D, Enum)) return 0;
554  Owner->addDecl(Enum);
555  Enum->startDefinition();
556
557  if (D->getDeclContext()->isFunctionOrMethod())
558    SemaRef.CurrentInstantiationScope->InstantiatedLocal(D, Enum);
559
560  llvm::SmallVector<Sema::DeclPtrTy, 4> Enumerators;
561
562  EnumConstantDecl *LastEnumConst = 0;
563  for (EnumDecl::enumerator_iterator EC = D->enumerator_begin(),
564         ECEnd = D->enumerator_end();
565       EC != ECEnd; ++EC) {
566    // The specified value for the enumerator.
567    OwningExprResult Value = SemaRef.Owned((Expr *)0);
568    if (Expr *UninstValue = EC->getInitExpr()) {
569      // The enumerator's value expression is not potentially evaluated.
570      EnterExpressionEvaluationContext Unevaluated(SemaRef,
571                                                   Action::Unevaluated);
572
573      Value = SemaRef.SubstExpr(UninstValue, TemplateArgs);
574    }
575
576    // Drop the initial value and continue.
577    bool isInvalid = false;
578    if (Value.isInvalid()) {
579      Value = SemaRef.Owned((Expr *)0);
580      isInvalid = true;
581    }
582
583    EnumConstantDecl *EnumConst
584      = SemaRef.CheckEnumConstant(Enum, LastEnumConst,
585                                  EC->getLocation(), EC->getIdentifier(),
586                                  move(Value));
587
588    if (isInvalid) {
589      if (EnumConst)
590        EnumConst->setInvalidDecl();
591      Enum->setInvalidDecl();
592    }
593
594    if (EnumConst) {
595      EnumConst->setAccess(Enum->getAccess());
596      Enum->addDecl(EnumConst);
597      Enumerators.push_back(Sema::DeclPtrTy::make(EnumConst));
598      LastEnumConst = EnumConst;
599
600      if (D->getDeclContext()->isFunctionOrMethod()) {
601        // If the enumeration is within a function or method, record the enum
602        // constant as a local.
603        SemaRef.CurrentInstantiationScope->InstantiatedLocal(*EC, EnumConst);
604      }
605    }
606  }
607
608  // FIXME: Fixup LBraceLoc and RBraceLoc
609  // FIXME: Empty Scope and AttributeList (required to handle attribute packed).
610  SemaRef.ActOnEnumBody(Enum->getLocation(), SourceLocation(), SourceLocation(),
611                        Sema::DeclPtrTy::make(Enum),
612                        &Enumerators[0], Enumerators.size(),
613                        0, 0);
614
615  return Enum;
616}
617
618Decl *TemplateDeclInstantiator::VisitEnumConstantDecl(EnumConstantDecl *D) {
619  assert(false && "EnumConstantDecls can only occur within EnumDecls.");
620  return 0;
621}
622
623namespace {
624  class SortDeclByLocation {
625    SourceManager &SourceMgr;
626
627  public:
628    explicit SortDeclByLocation(SourceManager &SourceMgr)
629      : SourceMgr(SourceMgr) { }
630
631    bool operator()(const Decl *X, const Decl *Y) const {
632      return SourceMgr.isBeforeInTranslationUnit(X->getLocation(),
633                                                 Y->getLocation());
634    }
635  };
636}
637
638Decl *TemplateDeclInstantiator::VisitClassTemplateDecl(ClassTemplateDecl *D) {
639  bool isFriend = (D->getFriendObjectKind() != Decl::FOK_None);
640
641  // Create a local instantiation scope for this class template, which
642  // will contain the instantiations of the template parameters.
643  Sema::LocalInstantiationScope Scope(SemaRef);
644  TemplateParameterList *TempParams = D->getTemplateParameters();
645  TemplateParameterList *InstParams = SubstTemplateParams(TempParams);
646  if (!InstParams)
647    return NULL;
648
649  CXXRecordDecl *Pattern = D->getTemplatedDecl();
650
651  // Instantiate the qualifier.  We have to do this first in case
652  // we're a friend declaration, because if we are then we need to put
653  // the new declaration in the appropriate context.
654  NestedNameSpecifier *Qualifier = Pattern->getQualifier();
655  if (Qualifier) {
656    Qualifier = SemaRef.SubstNestedNameSpecifier(Qualifier,
657                                                 Pattern->getQualifierRange(),
658                                                 TemplateArgs);
659    if (!Qualifier) return 0;
660  }
661
662  CXXRecordDecl *PrevDecl = 0;
663  ClassTemplateDecl *PrevClassTemplate = 0;
664
665  // If this isn't a friend, then it's a member template, in which
666  // case we just want to build the instantiation in the
667  // specialization.  If it is a friend, we want to build it in
668  // the appropriate context.
669  DeclContext *DC = Owner;
670  if (isFriend) {
671    if (Qualifier) {
672      CXXScopeSpec SS;
673      SS.setScopeRep(Qualifier);
674      SS.setRange(Pattern->getQualifierRange());
675      DC = SemaRef.computeDeclContext(SS);
676      if (!DC) return 0;
677    } else {
678      DC = SemaRef.FindInstantiatedContext(Pattern->getLocation(),
679                                           Pattern->getDeclContext(),
680                                           TemplateArgs);
681    }
682
683    // Look for a previous declaration of the template in the owning
684    // context.
685    LookupResult R(SemaRef, Pattern->getDeclName(), Pattern->getLocation(),
686                   Sema::LookupOrdinaryName, Sema::ForRedeclaration);
687    SemaRef.LookupQualifiedName(R, DC);
688
689    if (R.isSingleResult()) {
690      PrevClassTemplate = R.getAsSingle<ClassTemplateDecl>();
691      if (PrevClassTemplate)
692        PrevDecl = PrevClassTemplate->getTemplatedDecl();
693    }
694
695    if (!PrevClassTemplate && Qualifier) {
696      SemaRef.Diag(Pattern->getLocation(), diag::err_not_tag_in_scope)
697        << D->getTemplatedDecl()->getTagKind() << Pattern->getDeclName() << DC
698        << Pattern->getQualifierRange();
699      return 0;
700    }
701
702    bool AdoptedPreviousTemplateParams = false;
703    if (PrevClassTemplate) {
704      bool Complain = true;
705
706      // HACK: libstdc++ 4.2.1 contains an ill-formed friend class
707      // template for struct std::tr1::__detail::_Map_base, where the
708      // template parameters of the friend declaration don't match the
709      // template parameters of the original declaration. In this one
710      // case, we don't complain about the ill-formed friend
711      // declaration.
712      if (isFriend && Pattern->getIdentifier() &&
713          Pattern->getIdentifier()->isStr("_Map_base") &&
714          DC->isNamespace() &&
715          cast<NamespaceDecl>(DC)->getIdentifier() &&
716          cast<NamespaceDecl>(DC)->getIdentifier()->isStr("__detail")) {
717        DeclContext *DCParent = DC->getParent();
718        if (DCParent->isNamespace() &&
719            cast<NamespaceDecl>(DCParent)->getIdentifier() &&
720            cast<NamespaceDecl>(DCParent)->getIdentifier()->isStr("tr1")) {
721          DeclContext *DCParent2 = DCParent->getParent();
722          if (DCParent2->isNamespace() &&
723              cast<NamespaceDecl>(DCParent2)->getIdentifier() &&
724              cast<NamespaceDecl>(DCParent2)->getIdentifier()->isStr("std") &&
725              DCParent2->getParent()->isTranslationUnit())
726            Complain = false;
727        }
728      }
729
730      TemplateParameterList *PrevParams
731        = PrevClassTemplate->getTemplateParameters();
732
733      // Make sure the parameter lists match.
734      if (!SemaRef.TemplateParameterListsAreEqual(InstParams, PrevParams,
735                                                  Complain,
736                                                  Sema::TPL_TemplateMatch)) {
737        if (Complain)
738          return 0;
739
740        AdoptedPreviousTemplateParams = true;
741        InstParams = PrevParams;
742      }
743
744      // Do some additional validation, then merge default arguments
745      // from the existing declarations.
746      if (!AdoptedPreviousTemplateParams &&
747          SemaRef.CheckTemplateParameterList(InstParams, PrevParams,
748                                             Sema::TPC_ClassTemplate))
749        return 0;
750    }
751  }
752
753  CXXRecordDecl *RecordInst
754    = CXXRecordDecl::Create(SemaRef.Context, Pattern->getTagKind(), DC,
755                            Pattern->getLocation(), Pattern->getIdentifier(),
756                            Pattern->getTagKeywordLoc(), PrevDecl,
757                            /*DelayTypeCreation=*/true);
758
759  if (Qualifier)
760    RecordInst->setQualifierInfo(Qualifier, Pattern->getQualifierRange());
761
762  ClassTemplateDecl *Inst
763    = ClassTemplateDecl::Create(SemaRef.Context, DC, D->getLocation(),
764                                D->getIdentifier(), InstParams, RecordInst,
765                                PrevClassTemplate);
766  RecordInst->setDescribedClassTemplate(Inst);
767
768  if (isFriend) {
769    if (PrevClassTemplate)
770      Inst->setAccess(PrevClassTemplate->getAccess());
771    else
772      Inst->setAccess(D->getAccess());
773
774    Inst->setObjectOfFriendDecl(PrevClassTemplate != 0);
775    // TODO: do we want to track the instantiation progeny of this
776    // friend target decl?
777  } else {
778    Inst->setAccess(D->getAccess());
779    Inst->setInstantiatedFromMemberTemplate(D);
780  }
781
782  // Trigger creation of the type for the instantiation.
783  SemaRef.Context.getInjectedClassNameType(RecordInst,
784                  Inst->getInjectedClassNameSpecialization(SemaRef.Context));
785
786  // Finish handling of friends.
787  if (isFriend) {
788    DC->makeDeclVisibleInContext(Inst, /*Recoverable*/ false);
789    return Inst;
790  }
791
792  Owner->addDecl(Inst);
793
794  // First, we sort the partial specializations by location, so
795  // that we instantiate them in the order they were declared.
796  llvm::SmallVector<ClassTemplatePartialSpecializationDecl *, 4> PartialSpecs;
797  for (llvm::FoldingSet<ClassTemplatePartialSpecializationDecl>::iterator
798         P = D->getPartialSpecializations().begin(),
799         PEnd = D->getPartialSpecializations().end();
800       P != PEnd; ++P)
801    PartialSpecs.push_back(&*P);
802  std::sort(PartialSpecs.begin(), PartialSpecs.end(),
803            SortDeclByLocation(SemaRef.SourceMgr));
804
805  // Instantiate all of the partial specializations of this member class
806  // template.
807  for (unsigned I = 0, N = PartialSpecs.size(); I != N; ++I)
808    InstantiateClassTemplatePartialSpecialization(Inst, PartialSpecs[I]);
809
810  return Inst;
811}
812
813Decl *
814TemplateDeclInstantiator::VisitClassTemplatePartialSpecializationDecl(
815                                   ClassTemplatePartialSpecializationDecl *D) {
816  ClassTemplateDecl *ClassTemplate = D->getSpecializedTemplate();
817
818  // Lookup the already-instantiated declaration in the instantiation
819  // of the class template and return that.
820  DeclContext::lookup_result Found
821    = Owner->lookup(ClassTemplate->getDeclName());
822  if (Found.first == Found.second)
823    return 0;
824
825  ClassTemplateDecl *InstClassTemplate
826    = dyn_cast<ClassTemplateDecl>(*Found.first);
827  if (!InstClassTemplate)
828    return 0;
829
830  Decl *DCanon = D->getCanonicalDecl();
831  for (llvm::FoldingSet<ClassTemplatePartialSpecializationDecl>::iterator
832            P = InstClassTemplate->getPartialSpecializations().begin(),
833         PEnd = InstClassTemplate->getPartialSpecializations().end();
834       P != PEnd; ++P) {
835    if (P->getInstantiatedFromMember()->getCanonicalDecl() == DCanon)
836      return &*P;
837  }
838
839  return 0;
840}
841
842Decl *
843TemplateDeclInstantiator::VisitFunctionTemplateDecl(FunctionTemplateDecl *D) {
844  // Create a local instantiation scope for this function template, which
845  // will contain the instantiations of the template parameters and then get
846  // merged with the local instantiation scope for the function template
847  // itself.
848  Sema::LocalInstantiationScope Scope(SemaRef);
849
850  TemplateParameterList *TempParams = D->getTemplateParameters();
851  TemplateParameterList *InstParams = SubstTemplateParams(TempParams);
852  if (!InstParams)
853    return NULL;
854
855  FunctionDecl *Instantiated = 0;
856  if (CXXMethodDecl *DMethod = dyn_cast<CXXMethodDecl>(D->getTemplatedDecl()))
857    Instantiated = cast_or_null<FunctionDecl>(VisitCXXMethodDecl(DMethod,
858                                                                 InstParams));
859  else
860    Instantiated = cast_or_null<FunctionDecl>(VisitFunctionDecl(
861                                                          D->getTemplatedDecl(),
862                                                                InstParams));
863
864  if (!Instantiated)
865    return 0;
866
867  Instantiated->setAccess(D->getAccess());
868
869  // Link the instantiated function template declaration to the function
870  // template from which it was instantiated.
871  FunctionTemplateDecl *InstTemplate
872    = Instantiated->getDescribedFunctionTemplate();
873  InstTemplate->setAccess(D->getAccess());
874  assert(InstTemplate &&
875         "VisitFunctionDecl/CXXMethodDecl didn't create a template!");
876
877  bool isFriend = (InstTemplate->getFriendObjectKind() != Decl::FOK_None);
878
879  // Link the instantiation back to the pattern *unless* this is a
880  // non-definition friend declaration.
881  if (!InstTemplate->getInstantiatedFromMemberTemplate() &&
882      !(isFriend && !D->getTemplatedDecl()->isThisDeclarationADefinition()))
883    InstTemplate->setInstantiatedFromMemberTemplate(D);
884
885  // Make declarations visible in the appropriate context.
886  if (!isFriend)
887    Owner->addDecl(InstTemplate);
888
889  return InstTemplate;
890}
891
892Decl *TemplateDeclInstantiator::VisitCXXRecordDecl(CXXRecordDecl *D) {
893  CXXRecordDecl *PrevDecl = 0;
894  if (D->isInjectedClassName())
895    PrevDecl = cast<CXXRecordDecl>(Owner);
896  else if (D->getPreviousDeclaration()) {
897    NamedDecl *Prev = SemaRef.FindInstantiatedDecl(D->getLocation(),
898                                                   D->getPreviousDeclaration(),
899                                                   TemplateArgs);
900    if (!Prev) return 0;
901    PrevDecl = cast<CXXRecordDecl>(Prev);
902  }
903
904  CXXRecordDecl *Record
905    = CXXRecordDecl::Create(SemaRef.Context, D->getTagKind(), Owner,
906                            D->getLocation(), D->getIdentifier(),
907                            D->getTagKeywordLoc(), PrevDecl);
908
909  // Substitute the nested name specifier, if any.
910  if (SubstQualifier(D, Record))
911    return 0;
912
913  Record->setImplicit(D->isImplicit());
914  // FIXME: Check against AS_none is an ugly hack to work around the issue that
915  // the tag decls introduced by friend class declarations don't have an access
916  // specifier. Remove once this area of the code gets sorted out.
917  if (D->getAccess() != AS_none)
918    Record->setAccess(D->getAccess());
919  if (!D->isInjectedClassName())
920    Record->setInstantiationOfMemberClass(D, TSK_ImplicitInstantiation);
921
922  // If the original function was part of a friend declaration,
923  // inherit its namespace state.
924  if (Decl::FriendObjectKind FOK = D->getFriendObjectKind())
925    Record->setObjectOfFriendDecl(FOK == Decl::FOK_Declared);
926
927  Record->setAnonymousStructOrUnion(D->isAnonymousStructOrUnion());
928
929  Owner->addDecl(Record);
930  return Record;
931}
932
933/// Normal class members are of more specific types and therefore
934/// don't make it here.  This function serves two purposes:
935///   1) instantiating function templates
936///   2) substituting friend declarations
937/// FIXME: preserve function definitions in case #2
938Decl *TemplateDeclInstantiator::VisitFunctionDecl(FunctionDecl *D,
939                                       TemplateParameterList *TemplateParams) {
940  // Check whether there is already a function template specialization for
941  // this declaration.
942  FunctionTemplateDecl *FunctionTemplate = D->getDescribedFunctionTemplate();
943  void *InsertPos = 0;
944  if (FunctionTemplate && !TemplateParams) {
945    llvm::FoldingSetNodeID ID;
946    FunctionTemplateSpecializationInfo::Profile(ID,
947                             TemplateArgs.getInnermost().getFlatArgumentList(),
948                                       TemplateArgs.getInnermost().flat_size(),
949                                                SemaRef.Context);
950
951    FunctionTemplateSpecializationInfo *Info
952      = FunctionTemplate->getSpecializations().FindNodeOrInsertPos(ID,
953                                                                   InsertPos);
954
955    // If we already have a function template specialization, return it.
956    if (Info)
957      return Info->Function;
958  }
959
960  bool isFriend;
961  if (FunctionTemplate)
962    isFriend = (FunctionTemplate->getFriendObjectKind() != Decl::FOK_None);
963  else
964    isFriend = (D->getFriendObjectKind() != Decl::FOK_None);
965
966  bool MergeWithParentScope = (TemplateParams != 0) ||
967    !(isa<Decl>(Owner) &&
968      cast<Decl>(Owner)->isDefinedOutsideFunctionOrMethod());
969  Sema::LocalInstantiationScope Scope(SemaRef, MergeWithParentScope);
970
971  llvm::SmallVector<ParmVarDecl *, 4> Params;
972  TypeSourceInfo *TInfo = D->getTypeSourceInfo();
973  TInfo = SubstFunctionType(D, Params);
974  if (!TInfo)
975    return 0;
976  QualType T = TInfo->getType();
977
978  NestedNameSpecifier *Qualifier = D->getQualifier();
979  if (Qualifier) {
980    Qualifier = SemaRef.SubstNestedNameSpecifier(Qualifier,
981                                                 D->getQualifierRange(),
982                                                 TemplateArgs);
983    if (!Qualifier) return 0;
984  }
985
986  // If we're instantiating a local function declaration, put the result
987  // in the owner;  otherwise we need to find the instantiated context.
988  DeclContext *DC;
989  if (D->getDeclContext()->isFunctionOrMethod())
990    DC = Owner;
991  else if (isFriend && Qualifier) {
992    CXXScopeSpec SS;
993    SS.setScopeRep(Qualifier);
994    SS.setRange(D->getQualifierRange());
995    DC = SemaRef.computeDeclContext(SS);
996    if (!DC) return 0;
997  } else {
998    DC = SemaRef.FindInstantiatedContext(D->getLocation(), D->getDeclContext(),
999                                         TemplateArgs);
1000  }
1001
1002  FunctionDecl *Function =
1003      FunctionDecl::Create(SemaRef.Context, DC, D->getLocation(),
1004                           D->getDeclName(), T, TInfo,
1005                           D->getStorageClass(), D->getStorageClassAsWritten(),
1006                           D->isInlineSpecified(), D->hasWrittenPrototype());
1007
1008  if (Qualifier)
1009    Function->setQualifierInfo(Qualifier, D->getQualifierRange());
1010
1011  DeclContext *LexicalDC = Owner;
1012  if (!isFriend && D->isOutOfLine()) {
1013    assert(D->getDeclContext()->isFileContext());
1014    LexicalDC = D->getDeclContext();
1015  }
1016
1017  Function->setLexicalDeclContext(LexicalDC);
1018
1019  // Attach the parameters
1020  for (unsigned P = 0; P < Params.size(); ++P)
1021    Params[P]->setOwningFunction(Function);
1022  Function->setParams(Params.data(), Params.size());
1023
1024  if (TemplateParams) {
1025    // Our resulting instantiation is actually a function template, since we
1026    // are substituting only the outer template parameters. For example, given
1027    //
1028    //   template<typename T>
1029    //   struct X {
1030    //     template<typename U> friend void f(T, U);
1031    //   };
1032    //
1033    //   X<int> x;
1034    //
1035    // We are instantiating the friend function template "f" within X<int>,
1036    // which means substituting int for T, but leaving "f" as a friend function
1037    // template.
1038    // Build the function template itself.
1039    FunctionTemplate = FunctionTemplateDecl::Create(SemaRef.Context, DC,
1040                                                    Function->getLocation(),
1041                                                    Function->getDeclName(),
1042                                                    TemplateParams, Function);
1043    Function->setDescribedFunctionTemplate(FunctionTemplate);
1044
1045    FunctionTemplate->setLexicalDeclContext(LexicalDC);
1046
1047    if (isFriend && D->isThisDeclarationADefinition()) {
1048      // TODO: should we remember this connection regardless of whether
1049      // the friend declaration provided a body?
1050      FunctionTemplate->setInstantiatedFromMemberTemplate(
1051                                           D->getDescribedFunctionTemplate());
1052    }
1053  } else if (FunctionTemplate) {
1054    // Record this function template specialization.
1055    Function->setFunctionTemplateSpecialization(FunctionTemplate,
1056                                                &TemplateArgs.getInnermost(),
1057                                                InsertPos);
1058  } else if (isFriend && D->isThisDeclarationADefinition()) {
1059    // TODO: should we remember this connection regardless of whether
1060    // the friend declaration provided a body?
1061    Function->setInstantiationOfMemberFunction(D, TSK_ImplicitInstantiation);
1062  }
1063
1064  if (InitFunctionInstantiation(Function, D))
1065    Function->setInvalidDecl();
1066
1067  bool Redeclaration = false;
1068  bool OverloadableAttrRequired = false;
1069  bool isExplicitSpecialization = false;
1070
1071  LookupResult Previous(SemaRef, Function->getDeclName(), SourceLocation(),
1072                        Sema::LookupOrdinaryName, Sema::ForRedeclaration);
1073
1074  if (DependentFunctionTemplateSpecializationInfo *Info
1075        = D->getDependentSpecializationInfo()) {
1076    assert(isFriend && "non-friend has dependent specialization info?");
1077
1078    // This needs to be set now for future sanity.
1079    Function->setObjectOfFriendDecl(/*HasPrevious*/ true);
1080
1081    // Instantiate the explicit template arguments.
1082    TemplateArgumentListInfo ExplicitArgs(Info->getLAngleLoc(),
1083                                          Info->getRAngleLoc());
1084    for (unsigned I = 0, E = Info->getNumTemplateArgs(); I != E; ++I) {
1085      TemplateArgumentLoc Loc;
1086      if (SemaRef.Subst(Info->getTemplateArg(I), Loc, TemplateArgs))
1087        return 0;
1088
1089      ExplicitArgs.addArgument(Loc);
1090    }
1091
1092    // Map the candidate templates to their instantiations.
1093    for (unsigned I = 0, E = Info->getNumTemplates(); I != E; ++I) {
1094      Decl *Temp = SemaRef.FindInstantiatedDecl(D->getLocation(),
1095                                                Info->getTemplate(I),
1096                                                TemplateArgs);
1097      if (!Temp) return 0;
1098
1099      Previous.addDecl(cast<FunctionTemplateDecl>(Temp));
1100    }
1101
1102    if (SemaRef.CheckFunctionTemplateSpecialization(Function,
1103                                                    &ExplicitArgs,
1104                                                    Previous))
1105      Function->setInvalidDecl();
1106
1107    isExplicitSpecialization = true;
1108
1109  } else if (TemplateParams || !FunctionTemplate) {
1110    // Look only into the namespace where the friend would be declared to
1111    // find a previous declaration. This is the innermost enclosing namespace,
1112    // as described in ActOnFriendFunctionDecl.
1113    SemaRef.LookupQualifiedName(Previous, DC);
1114
1115    // In C++, the previous declaration we find might be a tag type
1116    // (class or enum). In this case, the new declaration will hide the
1117    // tag type. Note that this does does not apply if we're declaring a
1118    // typedef (C++ [dcl.typedef]p4).
1119    if (Previous.isSingleTagDecl())
1120      Previous.clear();
1121  }
1122
1123  SemaRef.CheckFunctionDeclaration(/*Scope*/ 0, Function, Previous,
1124                                   isExplicitSpecialization, Redeclaration,
1125                                   /*FIXME:*/OverloadableAttrRequired);
1126
1127  // If the original function was part of a friend declaration,
1128  // inherit its namespace state and add it to the owner.
1129  if (isFriend) {
1130    NamedDecl *ToFriendD = 0;
1131    NamedDecl *PrevDecl;
1132    if (TemplateParams) {
1133      ToFriendD = cast<NamedDecl>(FunctionTemplate);
1134      PrevDecl = FunctionTemplate->getPreviousDeclaration();
1135    } else {
1136      ToFriendD = Function;
1137      PrevDecl = Function->getPreviousDeclaration();
1138    }
1139    ToFriendD->setObjectOfFriendDecl(PrevDecl != NULL);
1140    DC->makeDeclVisibleInContext(ToFriendD, /*Recoverable=*/ false);
1141  }
1142
1143  if (Function->isOverloadedOperator() && !DC->isRecord() &&
1144      Function->isInIdentifierNamespace(Decl::IDNS_Ordinary)) {
1145    Function->setNonMemberOperator();
1146    if (FunctionTemplate) FunctionTemplate->setNonMemberOperator();
1147  }
1148
1149  return Function;
1150}
1151
1152Decl *
1153TemplateDeclInstantiator::VisitCXXMethodDecl(CXXMethodDecl *D,
1154                                      TemplateParameterList *TemplateParams) {
1155  FunctionTemplateDecl *FunctionTemplate = D->getDescribedFunctionTemplate();
1156  void *InsertPos = 0;
1157  if (FunctionTemplate && !TemplateParams) {
1158    // We are creating a function template specialization from a function
1159    // template. Check whether there is already a function template
1160    // specialization for this particular set of template arguments.
1161    llvm::FoldingSetNodeID ID;
1162    FunctionTemplateSpecializationInfo::Profile(ID,
1163                            TemplateArgs.getInnermost().getFlatArgumentList(),
1164                                      TemplateArgs.getInnermost().flat_size(),
1165                                                SemaRef.Context);
1166
1167    FunctionTemplateSpecializationInfo *Info
1168      = FunctionTemplate->getSpecializations().FindNodeOrInsertPos(ID,
1169                                                                   InsertPos);
1170
1171    // If we already have a function template specialization, return it.
1172    if (Info)
1173      return Info->Function;
1174  }
1175
1176  bool isFriend;
1177  if (FunctionTemplate)
1178    isFriend = (FunctionTemplate->getFriendObjectKind() != Decl::FOK_None);
1179  else
1180    isFriend = (D->getFriendObjectKind() != Decl::FOK_None);
1181
1182  bool MergeWithParentScope = (TemplateParams != 0) ||
1183    !(isa<Decl>(Owner) &&
1184      cast<Decl>(Owner)->isDefinedOutsideFunctionOrMethod());
1185  Sema::LocalInstantiationScope Scope(SemaRef, MergeWithParentScope);
1186
1187  llvm::SmallVector<ParmVarDecl *, 4> Params;
1188  TypeSourceInfo *TInfo = D->getTypeSourceInfo();
1189  TInfo = SubstFunctionType(D, Params);
1190  if (!TInfo)
1191    return 0;
1192  QualType T = TInfo->getType();
1193
1194  NestedNameSpecifier *Qualifier = D->getQualifier();
1195  if (Qualifier) {
1196    Qualifier = SemaRef.SubstNestedNameSpecifier(Qualifier,
1197                                                 D->getQualifierRange(),
1198                                                 TemplateArgs);
1199    if (!Qualifier) return 0;
1200  }
1201
1202  DeclContext *DC = Owner;
1203  if (isFriend) {
1204    if (Qualifier) {
1205      CXXScopeSpec SS;
1206      SS.setScopeRep(Qualifier);
1207      SS.setRange(D->getQualifierRange());
1208      DC = SemaRef.computeDeclContext(SS);
1209    } else {
1210      DC = SemaRef.FindInstantiatedContext(D->getLocation(),
1211                                           D->getDeclContext(),
1212                                           TemplateArgs);
1213    }
1214    if (!DC) return 0;
1215  }
1216
1217  // Build the instantiated method declaration.
1218  CXXRecordDecl *Record = cast<CXXRecordDecl>(DC);
1219  CXXMethodDecl *Method = 0;
1220
1221  DeclarationName Name = D->getDeclName();
1222  if (CXXConstructorDecl *Constructor = dyn_cast<CXXConstructorDecl>(D)) {
1223    QualType ClassTy = SemaRef.Context.getTypeDeclType(Record);
1224    Name = SemaRef.Context.DeclarationNames.getCXXConstructorName(
1225                                    SemaRef.Context.getCanonicalType(ClassTy));
1226    Method = CXXConstructorDecl::Create(SemaRef.Context, Record,
1227                                        Constructor->getLocation(),
1228                                        Name, T, TInfo,
1229                                        Constructor->isExplicit(),
1230                                        Constructor->isInlineSpecified(),
1231                                        false);
1232  } else if (CXXDestructorDecl *Destructor = dyn_cast<CXXDestructorDecl>(D)) {
1233    QualType ClassTy = SemaRef.Context.getTypeDeclType(Record);
1234    Name = SemaRef.Context.DeclarationNames.getCXXDestructorName(
1235                                   SemaRef.Context.getCanonicalType(ClassTy));
1236    Method = CXXDestructorDecl::Create(SemaRef.Context, Record,
1237                                       Destructor->getLocation(), Name,
1238                                       T, Destructor->isInlineSpecified(),
1239                                       false);
1240  } else if (CXXConversionDecl *Conversion = dyn_cast<CXXConversionDecl>(D)) {
1241    CanQualType ConvTy
1242      = SemaRef.Context.getCanonicalType(
1243                                      T->getAs<FunctionType>()->getResultType());
1244    Name = SemaRef.Context.DeclarationNames.getCXXConversionFunctionName(
1245                                                                      ConvTy);
1246    Method = CXXConversionDecl::Create(SemaRef.Context, Record,
1247                                       Conversion->getLocation(), Name,
1248                                       T, TInfo,
1249                                       Conversion->isInlineSpecified(),
1250                                       Conversion->isExplicit());
1251  } else {
1252    Method = CXXMethodDecl::Create(SemaRef.Context, Record, D->getLocation(),
1253                                   D->getDeclName(), T, TInfo,
1254                                   D->isStatic(),
1255                                   D->getStorageClassAsWritten(),
1256                                   D->isInlineSpecified());
1257  }
1258
1259  if (Qualifier)
1260    Method->setQualifierInfo(Qualifier, D->getQualifierRange());
1261
1262  if (TemplateParams) {
1263    // Our resulting instantiation is actually a function template, since we
1264    // are substituting only the outer template parameters. For example, given
1265    //
1266    //   template<typename T>
1267    //   struct X {
1268    //     template<typename U> void f(T, U);
1269    //   };
1270    //
1271    //   X<int> x;
1272    //
1273    // We are instantiating the member template "f" within X<int>, which means
1274    // substituting int for T, but leaving "f" as a member function template.
1275    // Build the function template itself.
1276    FunctionTemplate = FunctionTemplateDecl::Create(SemaRef.Context, Record,
1277                                                    Method->getLocation(),
1278                                                    Method->getDeclName(),
1279                                                    TemplateParams, Method);
1280    if (isFriend) {
1281      FunctionTemplate->setLexicalDeclContext(Owner);
1282      FunctionTemplate->setObjectOfFriendDecl(true);
1283    } else if (D->isOutOfLine())
1284      FunctionTemplate->setLexicalDeclContext(D->getLexicalDeclContext());
1285    Method->setDescribedFunctionTemplate(FunctionTemplate);
1286  } else if (FunctionTemplate) {
1287    // Record this function template specialization.
1288    Method->setFunctionTemplateSpecialization(FunctionTemplate,
1289                                              &TemplateArgs.getInnermost(),
1290                                              InsertPos);
1291  } else if (!isFriend) {
1292    // Record that this is an instantiation of a member function.
1293    Method->setInstantiationOfMemberFunction(D, TSK_ImplicitInstantiation);
1294  }
1295
1296  // If we are instantiating a member function defined
1297  // out-of-line, the instantiation will have the same lexical
1298  // context (which will be a namespace scope) as the template.
1299  if (isFriend) {
1300    Method->setLexicalDeclContext(Owner);
1301    Method->setObjectOfFriendDecl(true);
1302  } else if (D->isOutOfLine())
1303    Method->setLexicalDeclContext(D->getLexicalDeclContext());
1304
1305  // Attach the parameters
1306  for (unsigned P = 0; P < Params.size(); ++P)
1307    Params[P]->setOwningFunction(Method);
1308  Method->setParams(Params.data(), Params.size());
1309
1310  if (InitMethodInstantiation(Method, D))
1311    Method->setInvalidDecl();
1312
1313  LookupResult Previous(SemaRef, Name, SourceLocation(),
1314                        Sema::LookupOrdinaryName, Sema::ForRedeclaration);
1315
1316  if (!FunctionTemplate || TemplateParams || isFriend) {
1317    SemaRef.LookupQualifiedName(Previous, Record);
1318
1319    // In C++, the previous declaration we find might be a tag type
1320    // (class or enum). In this case, the new declaration will hide the
1321    // tag type. Note that this does does not apply if we're declaring a
1322    // typedef (C++ [dcl.typedef]p4).
1323    if (Previous.isSingleTagDecl())
1324      Previous.clear();
1325  }
1326
1327  bool Redeclaration = false;
1328  bool OverloadableAttrRequired = false;
1329  SemaRef.CheckFunctionDeclaration(0, Method, Previous, false, Redeclaration,
1330                                   /*FIXME:*/OverloadableAttrRequired);
1331
1332  if (D->isPure())
1333    SemaRef.CheckPureMethod(Method, SourceRange());
1334
1335  Method->setAccess(D->getAccess());
1336
1337  if (FunctionTemplate) {
1338    // If there's a function template, let our caller handle it.
1339  } else if (Method->isInvalidDecl() && !Previous.empty()) {
1340    // Don't hide a (potentially) valid declaration with an invalid one.
1341  } else {
1342    NamedDecl *DeclToAdd = (TemplateParams
1343                            ? cast<NamedDecl>(FunctionTemplate)
1344                            : Method);
1345    if (isFriend)
1346      Record->makeDeclVisibleInContext(DeclToAdd);
1347    else
1348      Owner->addDecl(DeclToAdd);
1349  }
1350
1351  return Method;
1352}
1353
1354Decl *TemplateDeclInstantiator::VisitCXXConstructorDecl(CXXConstructorDecl *D) {
1355  return VisitCXXMethodDecl(D);
1356}
1357
1358Decl *TemplateDeclInstantiator::VisitCXXDestructorDecl(CXXDestructorDecl *D) {
1359  return VisitCXXMethodDecl(D);
1360}
1361
1362Decl *TemplateDeclInstantiator::VisitCXXConversionDecl(CXXConversionDecl *D) {
1363  return VisitCXXMethodDecl(D);
1364}
1365
1366ParmVarDecl *TemplateDeclInstantiator::VisitParmVarDecl(ParmVarDecl *D) {
1367  return SemaRef.SubstParmVarDecl(D, TemplateArgs);
1368}
1369
1370Decl *TemplateDeclInstantiator::VisitTemplateTypeParmDecl(
1371                                                    TemplateTypeParmDecl *D) {
1372  // TODO: don't always clone when decls are refcounted.
1373  const Type* T = D->getTypeForDecl();
1374  assert(T->isTemplateTypeParmType());
1375  const TemplateTypeParmType *TTPT = T->getAs<TemplateTypeParmType>();
1376
1377  TemplateTypeParmDecl *Inst =
1378    TemplateTypeParmDecl::Create(SemaRef.Context, Owner, D->getLocation(),
1379                                 TTPT->getDepth() - 1, TTPT->getIndex(),
1380                                 TTPT->getName(),
1381                                 D->wasDeclaredWithTypename(),
1382                                 D->isParameterPack());
1383
1384  if (D->hasDefaultArgument())
1385    Inst->setDefaultArgument(D->getDefaultArgumentInfo(), false);
1386
1387  // Introduce this template parameter's instantiation into the instantiation
1388  // scope.
1389  SemaRef.CurrentInstantiationScope->InstantiatedLocal(D, Inst);
1390
1391  return Inst;
1392}
1393
1394Decl *TemplateDeclInstantiator::VisitNonTypeTemplateParmDecl(
1395                                                 NonTypeTemplateParmDecl *D) {
1396  // Substitute into the type of the non-type template parameter.
1397  QualType T;
1398  TypeSourceInfo *DI = D->getTypeSourceInfo();
1399  if (DI) {
1400    DI = SemaRef.SubstType(DI, TemplateArgs, D->getLocation(),
1401                           D->getDeclName());
1402    if (DI) T = DI->getType();
1403  } else {
1404    T = SemaRef.SubstType(D->getType(), TemplateArgs, D->getLocation(),
1405                          D->getDeclName());
1406    DI = 0;
1407  }
1408  if (T.isNull())
1409    return 0;
1410
1411  // Check that this type is acceptable for a non-type template parameter.
1412  bool Invalid = false;
1413  T = SemaRef.CheckNonTypeTemplateParameterType(T, D->getLocation());
1414  if (T.isNull()) {
1415    T = SemaRef.Context.IntTy;
1416    Invalid = true;
1417  }
1418
1419  NonTypeTemplateParmDecl *Param
1420    = NonTypeTemplateParmDecl::Create(SemaRef.Context, Owner, D->getLocation(),
1421                                      D->getDepth() - 1, D->getPosition(),
1422                                      D->getIdentifier(), T, DI);
1423  if (Invalid)
1424    Param->setInvalidDecl();
1425
1426  Param->setDefaultArgument(D->getDefaultArgument());
1427
1428  // Introduce this template parameter's instantiation into the instantiation
1429  // scope.
1430  SemaRef.CurrentInstantiationScope->InstantiatedLocal(D, Param);
1431  return Param;
1432}
1433
1434Decl *
1435TemplateDeclInstantiator::VisitTemplateTemplateParmDecl(
1436                                                  TemplateTemplateParmDecl *D) {
1437  // Instantiate the template parameter list of the template template parameter.
1438  TemplateParameterList *TempParams = D->getTemplateParameters();
1439  TemplateParameterList *InstParams;
1440  {
1441    // Perform the actual substitution of template parameters within a new,
1442    // local instantiation scope.
1443    Sema::LocalInstantiationScope Scope(SemaRef);
1444    InstParams = SubstTemplateParams(TempParams);
1445    if (!InstParams)
1446      return NULL;
1447  }
1448
1449  // Build the template template parameter.
1450  TemplateTemplateParmDecl *Param
1451    = TemplateTemplateParmDecl::Create(SemaRef.Context, Owner, D->getLocation(),
1452                                       D->getDepth() - 1, D->getPosition(),
1453                                       D->getIdentifier(), InstParams);
1454  Param->setDefaultArgument(D->getDefaultArgument());
1455
1456  // Introduce this template parameter's instantiation into the instantiation
1457  // scope.
1458  SemaRef.CurrentInstantiationScope->InstantiatedLocal(D, Param);
1459
1460  return Param;
1461}
1462
1463Decl *TemplateDeclInstantiator::VisitUsingDirectiveDecl(UsingDirectiveDecl *D) {
1464  // Using directives are never dependent, so they require no explicit
1465
1466  UsingDirectiveDecl *Inst
1467    = UsingDirectiveDecl::Create(SemaRef.Context, Owner, D->getLocation(),
1468                                 D->getNamespaceKeyLocation(),
1469                                 D->getQualifierRange(), D->getQualifier(),
1470                                 D->getIdentLocation(),
1471                                 D->getNominatedNamespace(),
1472                                 D->getCommonAncestor());
1473  Owner->addDecl(Inst);
1474  return Inst;
1475}
1476
1477Decl *TemplateDeclInstantiator::VisitUsingDecl(UsingDecl *D) {
1478  // The nested name specifier is non-dependent, so no transformation
1479  // is required.
1480
1481  // We only need to do redeclaration lookups if we're in a class
1482  // scope (in fact, it's not really even possible in non-class
1483  // scopes).
1484  bool CheckRedeclaration = Owner->isRecord();
1485
1486  LookupResult Prev(SemaRef, D->getDeclName(), D->getLocation(),
1487                    Sema::LookupUsingDeclName, Sema::ForRedeclaration);
1488
1489  UsingDecl *NewUD = UsingDecl::Create(SemaRef.Context, Owner,
1490                                       D->getLocation(),
1491                                       D->getNestedNameRange(),
1492                                       D->getUsingLocation(),
1493                                       D->getTargetNestedNameDecl(),
1494                                       D->getDeclName(),
1495                                       D->isTypeName());
1496
1497  CXXScopeSpec SS;
1498  SS.setScopeRep(D->getTargetNestedNameDecl());
1499  SS.setRange(D->getNestedNameRange());
1500
1501  if (CheckRedeclaration) {
1502    Prev.setHideTags(false);
1503    SemaRef.LookupQualifiedName(Prev, Owner);
1504
1505    // Check for invalid redeclarations.
1506    if (SemaRef.CheckUsingDeclRedeclaration(D->getUsingLocation(),
1507                                            D->isTypeName(), SS,
1508                                            D->getLocation(), Prev))
1509      NewUD->setInvalidDecl();
1510
1511  }
1512
1513  if (!NewUD->isInvalidDecl() &&
1514      SemaRef.CheckUsingDeclQualifier(D->getUsingLocation(), SS,
1515                                      D->getLocation()))
1516    NewUD->setInvalidDecl();
1517
1518  SemaRef.Context.setInstantiatedFromUsingDecl(NewUD, D);
1519  NewUD->setAccess(D->getAccess());
1520  Owner->addDecl(NewUD);
1521
1522  // Don't process the shadow decls for an invalid decl.
1523  if (NewUD->isInvalidDecl())
1524    return NewUD;
1525
1526  bool isFunctionScope = Owner->isFunctionOrMethod();
1527
1528  // Process the shadow decls.
1529  for (UsingDecl::shadow_iterator I = D->shadow_begin(), E = D->shadow_end();
1530         I != E; ++I) {
1531    UsingShadowDecl *Shadow = *I;
1532    NamedDecl *InstTarget =
1533      cast<NamedDecl>(SemaRef.FindInstantiatedDecl(Shadow->getLocation(),
1534                                                   Shadow->getTargetDecl(),
1535                                                   TemplateArgs));
1536
1537    if (CheckRedeclaration &&
1538        SemaRef.CheckUsingShadowDecl(NewUD, InstTarget, Prev))
1539      continue;
1540
1541    UsingShadowDecl *InstShadow
1542      = SemaRef.BuildUsingShadowDecl(/*Scope*/ 0, NewUD, InstTarget);
1543    SemaRef.Context.setInstantiatedFromUsingShadowDecl(InstShadow, Shadow);
1544
1545    if (isFunctionScope)
1546      SemaRef.CurrentInstantiationScope->InstantiatedLocal(Shadow, InstShadow);
1547  }
1548
1549  return NewUD;
1550}
1551
1552Decl *TemplateDeclInstantiator::VisitUsingShadowDecl(UsingShadowDecl *D) {
1553  // Ignore these;  we handle them in bulk when processing the UsingDecl.
1554  return 0;
1555}
1556
1557Decl * TemplateDeclInstantiator
1558    ::VisitUnresolvedUsingTypenameDecl(UnresolvedUsingTypenameDecl *D) {
1559  NestedNameSpecifier *NNS =
1560    SemaRef.SubstNestedNameSpecifier(D->getTargetNestedNameSpecifier(),
1561                                     D->getTargetNestedNameRange(),
1562                                     TemplateArgs);
1563  if (!NNS)
1564    return 0;
1565
1566  CXXScopeSpec SS;
1567  SS.setRange(D->getTargetNestedNameRange());
1568  SS.setScopeRep(NNS);
1569
1570  NamedDecl *UD =
1571    SemaRef.BuildUsingDeclaration(/*Scope*/ 0, D->getAccess(),
1572                                  D->getUsingLoc(), SS, D->getLocation(),
1573                                  D->getDeclName(), 0,
1574                                  /*instantiation*/ true,
1575                                  /*typename*/ true, D->getTypenameLoc());
1576  if (UD)
1577    SemaRef.Context.setInstantiatedFromUsingDecl(cast<UsingDecl>(UD), D);
1578
1579  return UD;
1580}
1581
1582Decl * TemplateDeclInstantiator
1583    ::VisitUnresolvedUsingValueDecl(UnresolvedUsingValueDecl *D) {
1584  NestedNameSpecifier *NNS =
1585    SemaRef.SubstNestedNameSpecifier(D->getTargetNestedNameSpecifier(),
1586                                     D->getTargetNestedNameRange(),
1587                                     TemplateArgs);
1588  if (!NNS)
1589    return 0;
1590
1591  CXXScopeSpec SS;
1592  SS.setRange(D->getTargetNestedNameRange());
1593  SS.setScopeRep(NNS);
1594
1595  NamedDecl *UD =
1596    SemaRef.BuildUsingDeclaration(/*Scope*/ 0, D->getAccess(),
1597                                  D->getUsingLoc(), SS, D->getLocation(),
1598                                  D->getDeclName(), 0,
1599                                  /*instantiation*/ true,
1600                                  /*typename*/ false, SourceLocation());
1601  if (UD)
1602    SemaRef.Context.setInstantiatedFromUsingDecl(cast<UsingDecl>(UD), D);
1603
1604  return UD;
1605}
1606
1607Decl *Sema::SubstDecl(Decl *D, DeclContext *Owner,
1608                      const MultiLevelTemplateArgumentList &TemplateArgs) {
1609  TemplateDeclInstantiator Instantiator(*this, Owner, TemplateArgs);
1610  if (D->isInvalidDecl())
1611    return 0;
1612
1613  return Instantiator.Visit(D);
1614}
1615
1616/// \brief Instantiates a nested template parameter list in the current
1617/// instantiation context.
1618///
1619/// \param L The parameter list to instantiate
1620///
1621/// \returns NULL if there was an error
1622TemplateParameterList *
1623TemplateDeclInstantiator::SubstTemplateParams(TemplateParameterList *L) {
1624  // Get errors for all the parameters before bailing out.
1625  bool Invalid = false;
1626
1627  unsigned N = L->size();
1628  typedef llvm::SmallVector<NamedDecl *, 8> ParamVector;
1629  ParamVector Params;
1630  Params.reserve(N);
1631  for (TemplateParameterList::iterator PI = L->begin(), PE = L->end();
1632       PI != PE; ++PI) {
1633    NamedDecl *D = cast_or_null<NamedDecl>(Visit(*PI));
1634    Params.push_back(D);
1635    Invalid = Invalid || !D || D->isInvalidDecl();
1636  }
1637
1638  // Clean up if we had an error.
1639  if (Invalid) {
1640    for (ParamVector::iterator PI = Params.begin(), PE = Params.end();
1641         PI != PE; ++PI)
1642      if (*PI)
1643        (*PI)->Destroy(SemaRef.Context);
1644    return NULL;
1645  }
1646
1647  TemplateParameterList *InstL
1648    = TemplateParameterList::Create(SemaRef.Context, L->getTemplateLoc(),
1649                                    L->getLAngleLoc(), &Params.front(), N,
1650                                    L->getRAngleLoc());
1651  return InstL;
1652}
1653
1654/// \brief Instantiate the declaration of a class template partial
1655/// specialization.
1656///
1657/// \param ClassTemplate the (instantiated) class template that is partially
1658// specialized by the instantiation of \p PartialSpec.
1659///
1660/// \param PartialSpec the (uninstantiated) class template partial
1661/// specialization that we are instantiating.
1662///
1663/// \returns true if there was an error, false otherwise.
1664bool
1665TemplateDeclInstantiator::InstantiateClassTemplatePartialSpecialization(
1666                                            ClassTemplateDecl *ClassTemplate,
1667                          ClassTemplatePartialSpecializationDecl *PartialSpec) {
1668  // Create a local instantiation scope for this class template partial
1669  // specialization, which will contain the instantiations of the template
1670  // parameters.
1671  Sema::LocalInstantiationScope Scope(SemaRef);
1672
1673  // Substitute into the template parameters of the class template partial
1674  // specialization.
1675  TemplateParameterList *TempParams = PartialSpec->getTemplateParameters();
1676  TemplateParameterList *InstParams = SubstTemplateParams(TempParams);
1677  if (!InstParams)
1678    return true;
1679
1680  // Substitute into the template arguments of the class template partial
1681  // specialization.
1682  const TemplateArgumentLoc *PartialSpecTemplateArgs
1683    = PartialSpec->getTemplateArgsAsWritten();
1684  unsigned N = PartialSpec->getNumTemplateArgsAsWritten();
1685
1686  TemplateArgumentListInfo InstTemplateArgs; // no angle locations
1687  for (unsigned I = 0; I != N; ++I) {
1688    TemplateArgumentLoc Loc;
1689    if (SemaRef.Subst(PartialSpecTemplateArgs[I], Loc, TemplateArgs))
1690      return true;
1691    InstTemplateArgs.addArgument(Loc);
1692  }
1693
1694
1695  // Check that the template argument list is well-formed for this
1696  // class template.
1697  TemplateArgumentListBuilder Converted(ClassTemplate->getTemplateParameters(),
1698                                        InstTemplateArgs.size());
1699  if (SemaRef.CheckTemplateArgumentList(ClassTemplate,
1700                                        PartialSpec->getLocation(),
1701                                        InstTemplateArgs,
1702                                        false,
1703                                        Converted))
1704    return true;
1705
1706  // Figure out where to insert this class template partial specialization
1707  // in the member template's set of class template partial specializations.
1708  llvm::FoldingSetNodeID ID;
1709  ClassTemplatePartialSpecializationDecl::Profile(ID,
1710                                                  Converted.getFlatArguments(),
1711                                                  Converted.flatSize(),
1712                                                  SemaRef.Context);
1713  void *InsertPos = 0;
1714  ClassTemplateSpecializationDecl *PrevDecl
1715    = ClassTemplate->getPartialSpecializations().FindNodeOrInsertPos(ID,
1716                                                                     InsertPos);
1717
1718  // Build the canonical type that describes the converted template
1719  // arguments of the class template partial specialization.
1720  QualType CanonType
1721    = SemaRef.Context.getTemplateSpecializationType(TemplateName(ClassTemplate),
1722                                                  Converted.getFlatArguments(),
1723                                                    Converted.flatSize());
1724
1725  // Build the fully-sugared type for this class template
1726  // specialization as the user wrote in the specialization
1727  // itself. This means that we'll pretty-print the type retrieved
1728  // from the specialization's declaration the way that the user
1729  // actually wrote the specialization, rather than formatting the
1730  // name based on the "canonical" representation used to store the
1731  // template arguments in the specialization.
1732  TypeSourceInfo *WrittenTy
1733    = SemaRef.Context.getTemplateSpecializationTypeInfo(
1734                                                    TemplateName(ClassTemplate),
1735                                                    PartialSpec->getLocation(),
1736                                                    InstTemplateArgs,
1737                                                    CanonType);
1738
1739  if (PrevDecl) {
1740    // We've already seen a partial specialization with the same template
1741    // parameters and template arguments. This can happen, for example, when
1742    // substituting the outer template arguments ends up causing two
1743    // class template partial specializations of a member class template
1744    // to have identical forms, e.g.,
1745    //
1746    //   template<typename T, typename U>
1747    //   struct Outer {
1748    //     template<typename X, typename Y> struct Inner;
1749    //     template<typename Y> struct Inner<T, Y>;
1750    //     template<typename Y> struct Inner<U, Y>;
1751    //   };
1752    //
1753    //   Outer<int, int> outer; // error: the partial specializations of Inner
1754    //                          // have the same signature.
1755    SemaRef.Diag(PartialSpec->getLocation(), diag::err_partial_spec_redeclared)
1756      << WrittenTy;
1757    SemaRef.Diag(PrevDecl->getLocation(), diag::note_prev_partial_spec_here)
1758      << SemaRef.Context.getTypeDeclType(PrevDecl);
1759    return true;
1760  }
1761
1762
1763  // Create the class template partial specialization declaration.
1764  ClassTemplatePartialSpecializationDecl *InstPartialSpec
1765    = ClassTemplatePartialSpecializationDecl::Create(SemaRef.Context, Owner,
1766                                                     PartialSpec->getLocation(),
1767                                                     InstParams,
1768                                                     ClassTemplate,
1769                                                     Converted,
1770                                                     InstTemplateArgs,
1771                                                     CanonType,
1772                                                     0);
1773  // Substitute the nested name specifier, if any.
1774  if (SubstQualifier(PartialSpec, InstPartialSpec))
1775    return 0;
1776
1777  InstPartialSpec->setInstantiatedFromMember(PartialSpec);
1778  InstPartialSpec->setTypeAsWritten(WrittenTy);
1779
1780  // Add this partial specialization to the set of class template partial
1781  // specializations.
1782  ClassTemplate->getPartialSpecializations().InsertNode(InstPartialSpec,
1783                                                        InsertPos);
1784  return false;
1785}
1786
1787TypeSourceInfo*
1788TemplateDeclInstantiator::SubstFunctionType(FunctionDecl *D,
1789                              llvm::SmallVectorImpl<ParmVarDecl *> &Params) {
1790  TypeSourceInfo *OldTInfo = D->getTypeSourceInfo();
1791  assert(OldTInfo && "substituting function without type source info");
1792  assert(Params.empty() && "parameter vector is non-empty at start");
1793  TypeSourceInfo *NewTInfo
1794    = SemaRef.SubstFunctionDeclType(OldTInfo, TemplateArgs,
1795                                    D->getTypeSpecStartLoc(),
1796                                    D->getDeclName());
1797  if (!NewTInfo)
1798    return 0;
1799
1800  if (NewTInfo != OldTInfo) {
1801    // Get parameters from the new type info.
1802    TypeLoc NewTL = NewTInfo->getTypeLoc();
1803    FunctionProtoTypeLoc *NewProtoLoc = cast<FunctionProtoTypeLoc>(&NewTL);
1804    assert(NewProtoLoc && "Missing prototype?");
1805    for (unsigned i = 0, i_end = NewProtoLoc->getNumArgs(); i != i_end; ++i)
1806      Params.push_back(NewProtoLoc->getArg(i));
1807  } else {
1808    // The function type itself was not dependent and therefore no
1809    // substitution occurred. However, we still need to instantiate
1810    // the function parameters themselves.
1811    TypeLoc OldTL = OldTInfo->getTypeLoc();
1812    FunctionProtoTypeLoc *OldProtoLoc = cast<FunctionProtoTypeLoc>(&OldTL);
1813    for (unsigned i = 0, i_end = OldProtoLoc->getNumArgs(); i != i_end; ++i) {
1814      ParmVarDecl *Parm = VisitParmVarDecl(OldProtoLoc->getArg(i));
1815      if (!Parm)
1816        return 0;
1817      Params.push_back(Parm);
1818    }
1819  }
1820  return NewTInfo;
1821}
1822
1823/// \brief Initializes the common fields of an instantiation function
1824/// declaration (New) from the corresponding fields of its template (Tmpl).
1825///
1826/// \returns true if there was an error
1827bool
1828TemplateDeclInstantiator::InitFunctionInstantiation(FunctionDecl *New,
1829                                                    FunctionDecl *Tmpl) {
1830  if (Tmpl->isDeleted())
1831    New->setDeleted();
1832
1833  // If we are performing substituting explicitly-specified template arguments
1834  // or deduced template arguments into a function template and we reach this
1835  // point, we are now past the point where SFINAE applies and have committed
1836  // to keeping the new function template specialization. We therefore
1837  // convert the active template instantiation for the function template
1838  // into a template instantiation for this specific function template
1839  // specialization, which is not a SFINAE context, so that we diagnose any
1840  // further errors in the declaration itself.
1841  typedef Sema::ActiveTemplateInstantiation ActiveInstType;
1842  ActiveInstType &ActiveInst = SemaRef.ActiveTemplateInstantiations.back();
1843  if (ActiveInst.Kind == ActiveInstType::ExplicitTemplateArgumentSubstitution ||
1844      ActiveInst.Kind == ActiveInstType::DeducedTemplateArgumentSubstitution) {
1845    if (FunctionTemplateDecl *FunTmpl
1846          = dyn_cast<FunctionTemplateDecl>((Decl *)ActiveInst.Entity)) {
1847      assert(FunTmpl->getTemplatedDecl() == Tmpl &&
1848             "Deduction from the wrong function template?");
1849      (void) FunTmpl;
1850      ActiveInst.Kind = ActiveInstType::TemplateInstantiation;
1851      ActiveInst.Entity = reinterpret_cast<uintptr_t>(New);
1852      --SemaRef.NonInstantiationEntries;
1853    }
1854  }
1855
1856  const FunctionProtoType *Proto = Tmpl->getType()->getAs<FunctionProtoType>();
1857  assert(Proto && "Function template without prototype?");
1858
1859  if (Proto->hasExceptionSpec() || Proto->hasAnyExceptionSpec() ||
1860      Proto->getNoReturnAttr()) {
1861    // The function has an exception specification or a "noreturn"
1862    // attribute. Substitute into each of the exception types.
1863    llvm::SmallVector<QualType, 4> Exceptions;
1864    for (unsigned I = 0, N = Proto->getNumExceptions(); I != N; ++I) {
1865      // FIXME: Poor location information!
1866      QualType T
1867        = SemaRef.SubstType(Proto->getExceptionType(I), TemplateArgs,
1868                            New->getLocation(), New->getDeclName());
1869      if (T.isNull() ||
1870          SemaRef.CheckSpecifiedExceptionType(T, New->getLocation()))
1871        continue;
1872
1873      Exceptions.push_back(T);
1874    }
1875
1876    // Rebuild the function type
1877
1878    const FunctionProtoType *NewProto
1879      = New->getType()->getAs<FunctionProtoType>();
1880    assert(NewProto && "Template instantiation without function prototype?");
1881    New->setType(SemaRef.Context.getFunctionType(NewProto->getResultType(),
1882                                                 NewProto->arg_type_begin(),
1883                                                 NewProto->getNumArgs(),
1884                                                 NewProto->isVariadic(),
1885                                                 NewProto->getTypeQuals(),
1886                                                 Proto->hasExceptionSpec(),
1887                                                 Proto->hasAnyExceptionSpec(),
1888                                                 Exceptions.size(),
1889                                                 Exceptions.data(),
1890                                                 Proto->getExtInfo()));
1891  }
1892
1893  return false;
1894}
1895
1896/// \brief Initializes common fields of an instantiated method
1897/// declaration (New) from the corresponding fields of its template
1898/// (Tmpl).
1899///
1900/// \returns true if there was an error
1901bool
1902TemplateDeclInstantiator::InitMethodInstantiation(CXXMethodDecl *New,
1903                                                  CXXMethodDecl *Tmpl) {
1904  if (InitFunctionInstantiation(New, Tmpl))
1905    return true;
1906
1907  CXXRecordDecl *Record = cast<CXXRecordDecl>(Owner);
1908  New->setAccess(Tmpl->getAccess());
1909  if (Tmpl->isVirtualAsWritten())
1910    Record->setMethodAsVirtual(New);
1911
1912  // FIXME: attributes
1913  // FIXME: New needs a pointer to Tmpl
1914  return false;
1915}
1916
1917/// \brief Instantiate the definition of the given function from its
1918/// template.
1919///
1920/// \param PointOfInstantiation the point at which the instantiation was
1921/// required. Note that this is not precisely a "point of instantiation"
1922/// for the function, but it's close.
1923///
1924/// \param Function the already-instantiated declaration of a
1925/// function template specialization or member function of a class template
1926/// specialization.
1927///
1928/// \param Recursive if true, recursively instantiates any functions that
1929/// are required by this instantiation.
1930///
1931/// \param DefinitionRequired if true, then we are performing an explicit
1932/// instantiation where the body of the function is required. Complain if
1933/// there is no such body.
1934void Sema::InstantiateFunctionDefinition(SourceLocation PointOfInstantiation,
1935                                         FunctionDecl *Function,
1936                                         bool Recursive,
1937                                         bool DefinitionRequired) {
1938  if (Function->isInvalidDecl())
1939    return;
1940
1941  assert(!Function->getBody() && "Already instantiated!");
1942
1943  // Never instantiate an explicit specialization.
1944  if (Function->getTemplateSpecializationKind() == TSK_ExplicitSpecialization)
1945    return;
1946
1947  // Find the function body that we'll be substituting.
1948  const FunctionDecl *PatternDecl = Function->getTemplateInstantiationPattern();
1949  Stmt *Pattern = 0;
1950  if (PatternDecl)
1951    Pattern = PatternDecl->getBody(PatternDecl);
1952
1953  if (!Pattern) {
1954    if (DefinitionRequired) {
1955      if (Function->getPrimaryTemplate())
1956        Diag(PointOfInstantiation,
1957             diag::err_explicit_instantiation_undefined_func_template)
1958          << Function->getPrimaryTemplate();
1959      else
1960        Diag(PointOfInstantiation,
1961             diag::err_explicit_instantiation_undefined_member)
1962          << 1 << Function->getDeclName() << Function->getDeclContext();
1963
1964      if (PatternDecl)
1965        Diag(PatternDecl->getLocation(),
1966             diag::note_explicit_instantiation_here);
1967    }
1968
1969    return;
1970  }
1971
1972  // C++0x [temp.explicit]p9:
1973  //   Except for inline functions, other explicit instantiation declarations
1974  //   have the effect of suppressing the implicit instantiation of the entity
1975  //   to which they refer.
1976  if (Function->getTemplateSpecializationKind()
1977        == TSK_ExplicitInstantiationDeclaration &&
1978      !PatternDecl->isInlined())
1979    return;
1980
1981  InstantiatingTemplate Inst(*this, PointOfInstantiation, Function);
1982  if (Inst)
1983    return;
1984
1985  // If we're performing recursive template instantiation, create our own
1986  // queue of pending implicit instantiations that we will instantiate later,
1987  // while we're still within our own instantiation context.
1988  std::deque<PendingImplicitInstantiation> SavedPendingImplicitInstantiations;
1989  if (Recursive)
1990    PendingImplicitInstantiations.swap(SavedPendingImplicitInstantiations);
1991
1992  ActOnStartOfFunctionDef(0, DeclPtrTy::make(Function));
1993
1994  // Introduce a new scope where local variable instantiations will be
1995  // recorded, unless we're actually a member function within a local
1996  // class, in which case we need to merge our results with the parent
1997  // scope (of the enclosing function).
1998  bool MergeWithParentScope = false;
1999  if (CXXRecordDecl *Rec = dyn_cast<CXXRecordDecl>(Function->getDeclContext()))
2000    MergeWithParentScope = Rec->isLocalClass();
2001
2002  LocalInstantiationScope Scope(*this, MergeWithParentScope);
2003
2004  // Introduce the instantiated function parameters into the local
2005  // instantiation scope.
2006  for (unsigned I = 0, N = PatternDecl->getNumParams(); I != N; ++I)
2007    Scope.InstantiatedLocal(PatternDecl->getParamDecl(I),
2008                            Function->getParamDecl(I));
2009
2010  // Enter the scope of this instantiation. We don't use
2011  // PushDeclContext because we don't have a scope.
2012  DeclContext *PreviousContext = CurContext;
2013  CurContext = Function;
2014
2015  MultiLevelTemplateArgumentList TemplateArgs =
2016    getTemplateInstantiationArgs(Function);
2017
2018  // If this is a constructor, instantiate the member initializers.
2019  if (const CXXConstructorDecl *Ctor =
2020        dyn_cast<CXXConstructorDecl>(PatternDecl)) {
2021    InstantiateMemInitializers(cast<CXXConstructorDecl>(Function), Ctor,
2022                               TemplateArgs);
2023  }
2024
2025  // Instantiate the function body.
2026  OwningStmtResult Body = SubstStmt(Pattern, TemplateArgs);
2027
2028  if (Body.isInvalid())
2029    Function->setInvalidDecl();
2030
2031  ActOnFinishFunctionBody(DeclPtrTy::make(Function), move(Body),
2032                          /*IsInstantiation=*/true);
2033
2034  PerformDependentDiagnostics(PatternDecl, TemplateArgs);
2035
2036  CurContext = PreviousContext;
2037
2038  DeclGroupRef DG(Function);
2039  Consumer.HandleTopLevelDecl(DG);
2040
2041  // This class may have local implicit instantiations that need to be
2042  // instantiation within this scope.
2043  PerformPendingImplicitInstantiations(/*LocalOnly=*/true);
2044  Scope.Exit();
2045
2046  if (Recursive) {
2047    // Instantiate any pending implicit instantiations found during the
2048    // instantiation of this template.
2049    PerformPendingImplicitInstantiations();
2050
2051    // Restore the set of pending implicit instantiations.
2052    PendingImplicitInstantiations.swap(SavedPendingImplicitInstantiations);
2053  }
2054}
2055
2056/// \brief Instantiate the definition of the given variable from its
2057/// template.
2058///
2059/// \param PointOfInstantiation the point at which the instantiation was
2060/// required. Note that this is not precisely a "point of instantiation"
2061/// for the function, but it's close.
2062///
2063/// \param Var the already-instantiated declaration of a static member
2064/// variable of a class template specialization.
2065///
2066/// \param Recursive if true, recursively instantiates any functions that
2067/// are required by this instantiation.
2068///
2069/// \param DefinitionRequired if true, then we are performing an explicit
2070/// instantiation where an out-of-line definition of the member variable
2071/// is required. Complain if there is no such definition.
2072void Sema::InstantiateStaticDataMemberDefinition(
2073                                          SourceLocation PointOfInstantiation,
2074                                                 VarDecl *Var,
2075                                                 bool Recursive,
2076                                                 bool DefinitionRequired) {
2077  if (Var->isInvalidDecl())
2078    return;
2079
2080  // Find the out-of-line definition of this static data member.
2081  VarDecl *Def = Var->getInstantiatedFromStaticDataMember();
2082  assert(Def && "This data member was not instantiated from a template?");
2083  assert(Def->isStaticDataMember() && "Not a static data member?");
2084  Def = Def->getOutOfLineDefinition();
2085
2086  if (!Def) {
2087    // We did not find an out-of-line definition of this static data member,
2088    // so we won't perform any instantiation. Rather, we rely on the user to
2089    // instantiate this definition (or provide a specialization for it) in
2090    // another translation unit.
2091    if (DefinitionRequired) {
2092      Def = Var->getInstantiatedFromStaticDataMember();
2093      Diag(PointOfInstantiation,
2094           diag::err_explicit_instantiation_undefined_member)
2095        << 2 << Var->getDeclName() << Var->getDeclContext();
2096      Diag(Def->getLocation(), diag::note_explicit_instantiation_here);
2097    }
2098
2099    return;
2100  }
2101
2102  // Never instantiate an explicit specialization.
2103  if (Var->getTemplateSpecializationKind() == TSK_ExplicitSpecialization)
2104    return;
2105
2106  // C++0x [temp.explicit]p9:
2107  //   Except for inline functions, other explicit instantiation declarations
2108  //   have the effect of suppressing the implicit instantiation of the entity
2109  //   to which they refer.
2110  if (Var->getTemplateSpecializationKind()
2111        == TSK_ExplicitInstantiationDeclaration)
2112    return;
2113
2114  InstantiatingTemplate Inst(*this, PointOfInstantiation, Var);
2115  if (Inst)
2116    return;
2117
2118  // If we're performing recursive template instantiation, create our own
2119  // queue of pending implicit instantiations that we will instantiate later,
2120  // while we're still within our own instantiation context.
2121  std::deque<PendingImplicitInstantiation> SavedPendingImplicitInstantiations;
2122  if (Recursive)
2123    PendingImplicitInstantiations.swap(SavedPendingImplicitInstantiations);
2124
2125  // Enter the scope of this instantiation. We don't use
2126  // PushDeclContext because we don't have a scope.
2127  DeclContext *PreviousContext = CurContext;
2128  CurContext = Var->getDeclContext();
2129
2130  VarDecl *OldVar = Var;
2131  Var = cast_or_null<VarDecl>(SubstDecl(Def, Var->getDeclContext(),
2132                                          getTemplateInstantiationArgs(Var)));
2133  CurContext = PreviousContext;
2134
2135  if (Var) {
2136    MemberSpecializationInfo *MSInfo = OldVar->getMemberSpecializationInfo();
2137    assert(MSInfo && "Missing member specialization information?");
2138    Var->setTemplateSpecializationKind(MSInfo->getTemplateSpecializationKind(),
2139                                       MSInfo->getPointOfInstantiation());
2140    DeclGroupRef DG(Var);
2141    Consumer.HandleTopLevelDecl(DG);
2142  }
2143
2144  if (Recursive) {
2145    // Instantiate any pending implicit instantiations found during the
2146    // instantiation of this template.
2147    PerformPendingImplicitInstantiations();
2148
2149    // Restore the set of pending implicit instantiations.
2150    PendingImplicitInstantiations.swap(SavedPendingImplicitInstantiations);
2151  }
2152}
2153
2154void
2155Sema::InstantiateMemInitializers(CXXConstructorDecl *New,
2156                                 const CXXConstructorDecl *Tmpl,
2157                           const MultiLevelTemplateArgumentList &TemplateArgs) {
2158
2159  llvm::SmallVector<MemInitTy*, 4> NewInits;
2160  bool AnyErrors = false;
2161
2162  // Instantiate all the initializers.
2163  for (CXXConstructorDecl::init_const_iterator Inits = Tmpl->init_begin(),
2164                                            InitsEnd = Tmpl->init_end();
2165       Inits != InitsEnd; ++Inits) {
2166    CXXBaseOrMemberInitializer *Init = *Inits;
2167
2168    SourceLocation LParenLoc, RParenLoc;
2169    ASTOwningVector<&ActionBase::DeleteExpr> NewArgs(*this);
2170    llvm::SmallVector<SourceLocation, 4> CommaLocs;
2171
2172    // Instantiate the initializer.
2173    if (InstantiateInitializer(*this, Init->getInit(), TemplateArgs,
2174                               LParenLoc, CommaLocs, NewArgs, RParenLoc)) {
2175      AnyErrors = true;
2176      continue;
2177    }
2178
2179    MemInitResult NewInit;
2180    if (Init->isBaseInitializer()) {
2181      TypeSourceInfo *BaseTInfo = SubstType(Init->getBaseClassInfo(),
2182                                            TemplateArgs,
2183                                            Init->getSourceLocation(),
2184                                            New->getDeclName());
2185      if (!BaseTInfo) {
2186        AnyErrors = true;
2187        New->setInvalidDecl();
2188        continue;
2189      }
2190
2191      NewInit = BuildBaseInitializer(BaseTInfo->getType(), BaseTInfo,
2192                                     (Expr **)NewArgs.data(),
2193                                     NewArgs.size(),
2194                                     Init->getLParenLoc(),
2195                                     Init->getRParenLoc(),
2196                                     New->getParent());
2197    } else if (Init->isMemberInitializer()) {
2198      FieldDecl *Member;
2199
2200      // Is this an anonymous union?
2201      if (FieldDecl *UnionInit = Init->getAnonUnionMember())
2202        Member = cast<FieldDecl>(FindInstantiatedDecl(Init->getMemberLocation(),
2203                                                      UnionInit, TemplateArgs));
2204      else
2205        Member = cast<FieldDecl>(FindInstantiatedDecl(Init->getMemberLocation(),
2206                                                      Init->getMember(),
2207                                                      TemplateArgs));
2208
2209      NewInit = BuildMemberInitializer(Member, (Expr **)NewArgs.data(),
2210                                       NewArgs.size(),
2211                                       Init->getSourceLocation(),
2212                                       Init->getLParenLoc(),
2213                                       Init->getRParenLoc());
2214    }
2215
2216    if (NewInit.isInvalid()) {
2217      AnyErrors = true;
2218      New->setInvalidDecl();
2219    } else {
2220      // FIXME: It would be nice if ASTOwningVector had a release function.
2221      NewArgs.take();
2222
2223      NewInits.push_back((MemInitTy *)NewInit.get());
2224    }
2225  }
2226
2227  // Assign all the initializers to the new constructor.
2228  ActOnMemInitializers(DeclPtrTy::make(New),
2229                       /*FIXME: ColonLoc */
2230                       SourceLocation(),
2231                       NewInits.data(), NewInits.size(),
2232                       AnyErrors);
2233}
2234
2235// TODO: this could be templated if the various decl types used the
2236// same method name.
2237static bool isInstantiationOf(ClassTemplateDecl *Pattern,
2238                              ClassTemplateDecl *Instance) {
2239  Pattern = Pattern->getCanonicalDecl();
2240
2241  do {
2242    Instance = Instance->getCanonicalDecl();
2243    if (Pattern == Instance) return true;
2244    Instance = Instance->getInstantiatedFromMemberTemplate();
2245  } while (Instance);
2246
2247  return false;
2248}
2249
2250static bool isInstantiationOf(FunctionTemplateDecl *Pattern,
2251                              FunctionTemplateDecl *Instance) {
2252  Pattern = Pattern->getCanonicalDecl();
2253
2254  do {
2255    Instance = Instance->getCanonicalDecl();
2256    if (Pattern == Instance) return true;
2257    Instance = Instance->getInstantiatedFromMemberTemplate();
2258  } while (Instance);
2259
2260  return false;
2261}
2262
2263static bool
2264isInstantiationOf(ClassTemplatePartialSpecializationDecl *Pattern,
2265                  ClassTemplatePartialSpecializationDecl *Instance) {
2266  Pattern
2267    = cast<ClassTemplatePartialSpecializationDecl>(Pattern->getCanonicalDecl());
2268  do {
2269    Instance = cast<ClassTemplatePartialSpecializationDecl>(
2270                                                Instance->getCanonicalDecl());
2271    if (Pattern == Instance)
2272      return true;
2273    Instance = Instance->getInstantiatedFromMember();
2274  } while (Instance);
2275
2276  return false;
2277}
2278
2279static bool isInstantiationOf(CXXRecordDecl *Pattern,
2280                              CXXRecordDecl *Instance) {
2281  Pattern = Pattern->getCanonicalDecl();
2282
2283  do {
2284    Instance = Instance->getCanonicalDecl();
2285    if (Pattern == Instance) return true;
2286    Instance = Instance->getInstantiatedFromMemberClass();
2287  } while (Instance);
2288
2289  return false;
2290}
2291
2292static bool isInstantiationOf(FunctionDecl *Pattern,
2293                              FunctionDecl *Instance) {
2294  Pattern = Pattern->getCanonicalDecl();
2295
2296  do {
2297    Instance = Instance->getCanonicalDecl();
2298    if (Pattern == Instance) return true;
2299    Instance = Instance->getInstantiatedFromMemberFunction();
2300  } while (Instance);
2301
2302  return false;
2303}
2304
2305static bool isInstantiationOf(EnumDecl *Pattern,
2306                              EnumDecl *Instance) {
2307  Pattern = Pattern->getCanonicalDecl();
2308
2309  do {
2310    Instance = Instance->getCanonicalDecl();
2311    if (Pattern == Instance) return true;
2312    Instance = Instance->getInstantiatedFromMemberEnum();
2313  } while (Instance);
2314
2315  return false;
2316}
2317
2318static bool isInstantiationOf(UsingShadowDecl *Pattern,
2319                              UsingShadowDecl *Instance,
2320                              ASTContext &C) {
2321  return C.getInstantiatedFromUsingShadowDecl(Instance) == Pattern;
2322}
2323
2324static bool isInstantiationOf(UsingDecl *Pattern,
2325                              UsingDecl *Instance,
2326                              ASTContext &C) {
2327  return C.getInstantiatedFromUsingDecl(Instance) == Pattern;
2328}
2329
2330static bool isInstantiationOf(UnresolvedUsingValueDecl *Pattern,
2331                              UsingDecl *Instance,
2332                              ASTContext &C) {
2333  return C.getInstantiatedFromUsingDecl(Instance) == Pattern;
2334}
2335
2336static bool isInstantiationOf(UnresolvedUsingTypenameDecl *Pattern,
2337                              UsingDecl *Instance,
2338                              ASTContext &C) {
2339  return C.getInstantiatedFromUsingDecl(Instance) == Pattern;
2340}
2341
2342static bool isInstantiationOfStaticDataMember(VarDecl *Pattern,
2343                                              VarDecl *Instance) {
2344  assert(Instance->isStaticDataMember());
2345
2346  Pattern = Pattern->getCanonicalDecl();
2347
2348  do {
2349    Instance = Instance->getCanonicalDecl();
2350    if (Pattern == Instance) return true;
2351    Instance = Instance->getInstantiatedFromStaticDataMember();
2352  } while (Instance);
2353
2354  return false;
2355}
2356
2357// Other is the prospective instantiation
2358// D is the prospective pattern
2359static bool isInstantiationOf(ASTContext &Ctx, NamedDecl *D, Decl *Other) {
2360  if (D->getKind() != Other->getKind()) {
2361    if (UnresolvedUsingTypenameDecl *UUD
2362          = dyn_cast<UnresolvedUsingTypenameDecl>(D)) {
2363      if (UsingDecl *UD = dyn_cast<UsingDecl>(Other)) {
2364        return isInstantiationOf(UUD, UD, Ctx);
2365      }
2366    }
2367
2368    if (UnresolvedUsingValueDecl *UUD
2369          = dyn_cast<UnresolvedUsingValueDecl>(D)) {
2370      if (UsingDecl *UD = dyn_cast<UsingDecl>(Other)) {
2371        return isInstantiationOf(UUD, UD, Ctx);
2372      }
2373    }
2374
2375    return false;
2376  }
2377
2378  if (CXXRecordDecl *Record = dyn_cast<CXXRecordDecl>(Other))
2379    return isInstantiationOf(cast<CXXRecordDecl>(D), Record);
2380
2381  if (FunctionDecl *Function = dyn_cast<FunctionDecl>(Other))
2382    return isInstantiationOf(cast<FunctionDecl>(D), Function);
2383
2384  if (EnumDecl *Enum = dyn_cast<EnumDecl>(Other))
2385    return isInstantiationOf(cast<EnumDecl>(D), Enum);
2386
2387  if (VarDecl *Var = dyn_cast<VarDecl>(Other))
2388    if (Var->isStaticDataMember())
2389      return isInstantiationOfStaticDataMember(cast<VarDecl>(D), Var);
2390
2391  if (ClassTemplateDecl *Temp = dyn_cast<ClassTemplateDecl>(Other))
2392    return isInstantiationOf(cast<ClassTemplateDecl>(D), Temp);
2393
2394  if (FunctionTemplateDecl *Temp = dyn_cast<FunctionTemplateDecl>(Other))
2395    return isInstantiationOf(cast<FunctionTemplateDecl>(D), Temp);
2396
2397  if (ClassTemplatePartialSpecializationDecl *PartialSpec
2398        = dyn_cast<ClassTemplatePartialSpecializationDecl>(Other))
2399    return isInstantiationOf(cast<ClassTemplatePartialSpecializationDecl>(D),
2400                             PartialSpec);
2401
2402  if (FieldDecl *Field = dyn_cast<FieldDecl>(Other)) {
2403    if (!Field->getDeclName()) {
2404      // This is an unnamed field.
2405      return Ctx.getInstantiatedFromUnnamedFieldDecl(Field) ==
2406        cast<FieldDecl>(D);
2407    }
2408  }
2409
2410  if (UsingDecl *Using = dyn_cast<UsingDecl>(Other))
2411    return isInstantiationOf(cast<UsingDecl>(D), Using, Ctx);
2412
2413  if (UsingShadowDecl *Shadow = dyn_cast<UsingShadowDecl>(Other))
2414    return isInstantiationOf(cast<UsingShadowDecl>(D), Shadow, Ctx);
2415
2416  return D->getDeclName() && isa<NamedDecl>(Other) &&
2417    D->getDeclName() == cast<NamedDecl>(Other)->getDeclName();
2418}
2419
2420template<typename ForwardIterator>
2421static NamedDecl *findInstantiationOf(ASTContext &Ctx,
2422                                      NamedDecl *D,
2423                                      ForwardIterator first,
2424                                      ForwardIterator last) {
2425  for (; first != last; ++first)
2426    if (isInstantiationOf(Ctx, D, *first))
2427      return cast<NamedDecl>(*first);
2428
2429  return 0;
2430}
2431
2432/// \brief Finds the instantiation of the given declaration context
2433/// within the current instantiation.
2434///
2435/// \returns NULL if there was an error
2436DeclContext *Sema::FindInstantiatedContext(SourceLocation Loc, DeclContext* DC,
2437                          const MultiLevelTemplateArgumentList &TemplateArgs) {
2438  if (NamedDecl *D = dyn_cast<NamedDecl>(DC)) {
2439    Decl* ID = FindInstantiatedDecl(Loc, D, TemplateArgs);
2440    return cast_or_null<DeclContext>(ID);
2441  } else return DC;
2442}
2443
2444/// \brief Find the instantiation of the given declaration within the
2445/// current instantiation.
2446///
2447/// This routine is intended to be used when \p D is a declaration
2448/// referenced from within a template, that needs to mapped into the
2449/// corresponding declaration within an instantiation. For example,
2450/// given:
2451///
2452/// \code
2453/// template<typename T>
2454/// struct X {
2455///   enum Kind {
2456///     KnownValue = sizeof(T)
2457///   };
2458///
2459///   bool getKind() const { return KnownValue; }
2460/// };
2461///
2462/// template struct X<int>;
2463/// \endcode
2464///
2465/// In the instantiation of X<int>::getKind(), we need to map the
2466/// EnumConstantDecl for KnownValue (which refers to
2467/// X<T>::<Kind>::KnownValue) to its instantiation
2468/// (X<int>::<Kind>::KnownValue). InstantiateCurrentDeclRef() performs
2469/// this mapping from within the instantiation of X<int>.
2470NamedDecl *Sema::FindInstantiatedDecl(SourceLocation Loc, NamedDecl *D,
2471                          const MultiLevelTemplateArgumentList &TemplateArgs) {
2472  DeclContext *ParentDC = D->getDeclContext();
2473  if (isa<ParmVarDecl>(D) || isa<NonTypeTemplateParmDecl>(D) ||
2474      isa<TemplateTypeParmDecl>(D) || isa<TemplateTemplateParmDecl>(D) ||
2475      ParentDC->isFunctionOrMethod()) {
2476    // D is a local of some kind. Look into the map of local
2477    // declarations to their instantiations.
2478    return cast<NamedDecl>(CurrentInstantiationScope->getInstantiationOf(D));
2479  }
2480
2481  if (CXXRecordDecl *Record = dyn_cast<CXXRecordDecl>(D)) {
2482    if (!Record->isDependentContext())
2483      return D;
2484
2485    // If the RecordDecl is actually the injected-class-name or a
2486    // "templated" declaration for a class template, class template
2487    // partial specialization, or a member class of a class template,
2488    // substitute into the injected-class-name of the class template
2489    // or partial specialization to find the new DeclContext.
2490    QualType T;
2491    ClassTemplateDecl *ClassTemplate = Record->getDescribedClassTemplate();
2492
2493    if (ClassTemplate) {
2494      T = ClassTemplate->getInjectedClassNameSpecialization(Context);
2495    } else if (ClassTemplatePartialSpecializationDecl *PartialSpec
2496                 = dyn_cast<ClassTemplatePartialSpecializationDecl>(Record)) {
2497      ClassTemplate = PartialSpec->getSpecializedTemplate();
2498
2499      // If we call SubstType with an InjectedClassNameType here we
2500      // can end up in an infinite loop.
2501      T = Context.getTypeDeclType(Record);
2502      assert(isa<InjectedClassNameType>(T) &&
2503             "type of partial specialization is not an InjectedClassNameType");
2504      T = cast<InjectedClassNameType>(T)->getUnderlyingType();
2505    }
2506
2507    if (!T.isNull()) {
2508      // Substitute into the injected-class-name to get the type
2509      // corresponding to the instantiation we want, which may also be
2510      // the current instantiation (if we're in a template
2511      // definition). This substitution should never fail, since we
2512      // know we can instantiate the injected-class-name or we
2513      // wouldn't have gotten to the injected-class-name!
2514
2515      // FIXME: Can we use the CurrentInstantiationScope to avoid this
2516      // extra instantiation in the common case?
2517      T = SubstType(T, TemplateArgs, SourceLocation(), DeclarationName());
2518      assert(!T.isNull() && "Instantiation of injected-class-name cannot fail.");
2519
2520      if (!T->isDependentType()) {
2521        assert(T->isRecordType() && "Instantiation must produce a record type");
2522        return T->getAs<RecordType>()->getDecl();
2523      }
2524
2525      // We are performing "partial" template instantiation to create
2526      // the member declarations for the members of a class template
2527      // specialization. Therefore, D is actually referring to something
2528      // in the current instantiation. Look through the current
2529      // context, which contains actual instantiations, to find the
2530      // instantiation of the "current instantiation" that D refers
2531      // to.
2532      bool SawNonDependentContext = false;
2533      for (DeclContext *DC = CurContext; !DC->isFileContext();
2534           DC = DC->getParent()) {
2535        if (ClassTemplateSpecializationDecl *Spec
2536                          = dyn_cast<ClassTemplateSpecializationDecl>(DC))
2537          if (isInstantiationOf(ClassTemplate,
2538                                Spec->getSpecializedTemplate()))
2539            return Spec;
2540
2541        if (!DC->isDependentContext())
2542          SawNonDependentContext = true;
2543      }
2544
2545      // We're performing "instantiation" of a member of the current
2546      // instantiation while we are type-checking the
2547      // definition. Compute the declaration context and return that.
2548      assert(!SawNonDependentContext &&
2549             "No dependent context while instantiating record");
2550      DeclContext *DC = computeDeclContext(T);
2551      assert(DC &&
2552             "Unable to find declaration for the current instantiation");
2553      return cast<CXXRecordDecl>(DC);
2554    }
2555
2556    // Fall through to deal with other dependent record types (e.g.,
2557    // anonymous unions in class templates).
2558  }
2559
2560  if (!ParentDC->isDependentContext())
2561    return D;
2562
2563  ParentDC = FindInstantiatedContext(Loc, ParentDC, TemplateArgs);
2564  if (!ParentDC)
2565    return 0;
2566
2567  if (ParentDC != D->getDeclContext()) {
2568    // We performed some kind of instantiation in the parent context,
2569    // so now we need to look into the instantiated parent context to
2570    // find the instantiation of the declaration D.
2571
2572    // If our context used to be dependent, we may need to instantiate
2573    // it before performing lookup into that context.
2574    if (CXXRecordDecl *Spec = dyn_cast<CXXRecordDecl>(ParentDC)) {
2575      if (!Spec->isDependentContext()) {
2576        QualType T = Context.getTypeDeclType(Spec);
2577        const RecordType *Tag = T->getAs<RecordType>();
2578        assert(Tag && "type of non-dependent record is not a RecordType");
2579        if (!Tag->isBeingDefined() &&
2580            RequireCompleteType(Loc, T, diag::err_incomplete_type))
2581          return 0;
2582      }
2583    }
2584
2585    NamedDecl *Result = 0;
2586    if (D->getDeclName()) {
2587      DeclContext::lookup_result Found = ParentDC->lookup(D->getDeclName());
2588      Result = findInstantiationOf(Context, D, Found.first, Found.second);
2589    } else {
2590      // Since we don't have a name for the entity we're looking for,
2591      // our only option is to walk through all of the declarations to
2592      // find that name. This will occur in a few cases:
2593      //
2594      //   - anonymous struct/union within a template
2595      //   - unnamed class/struct/union/enum within a template
2596      //
2597      // FIXME: Find a better way to find these instantiations!
2598      Result = findInstantiationOf(Context, D,
2599                                   ParentDC->decls_begin(),
2600                                   ParentDC->decls_end());
2601    }
2602
2603    // UsingShadowDecls can instantiate to nothing because of using hiding.
2604    assert((Result || isa<UsingShadowDecl>(D) || D->isInvalidDecl() ||
2605            cast<Decl>(ParentDC)->isInvalidDecl())
2606           && "Unable to find instantiation of declaration!");
2607
2608    D = Result;
2609  }
2610
2611  return D;
2612}
2613
2614/// \brief Performs template instantiation for all implicit template
2615/// instantiations we have seen until this point.
2616void Sema::PerformPendingImplicitInstantiations(bool LocalOnly) {
2617  while (!PendingLocalImplicitInstantiations.empty() ||
2618         (!LocalOnly && !PendingImplicitInstantiations.empty())) {
2619    PendingImplicitInstantiation Inst;
2620
2621    if (PendingLocalImplicitInstantiations.empty()) {
2622      Inst = PendingImplicitInstantiations.front();
2623      PendingImplicitInstantiations.pop_front();
2624    } else {
2625      Inst = PendingLocalImplicitInstantiations.front();
2626      PendingLocalImplicitInstantiations.pop_front();
2627    }
2628
2629    // Instantiate function definitions
2630    if (FunctionDecl *Function = dyn_cast<FunctionDecl>(Inst.first)) {
2631      PrettyStackTraceActionsDecl CrashInfo(DeclPtrTy::make(Function),
2632                                            Function->getLocation(), *this,
2633                                            Context.getSourceManager(),
2634                                           "instantiating function definition");
2635
2636      if (!Function->getBody())
2637        InstantiateFunctionDefinition(/*FIXME:*/Inst.second, Function, true);
2638      continue;
2639    }
2640
2641    // Instantiate static data member definitions.
2642    VarDecl *Var = cast<VarDecl>(Inst.first);
2643    assert(Var->isStaticDataMember() && "Not a static data member?");
2644
2645    // Don't try to instantiate declarations if the most recent redeclaration
2646    // is invalid.
2647    if (Var->getMostRecentDeclaration()->isInvalidDecl())
2648      continue;
2649
2650    // Check if the most recent declaration has changed the specialization kind
2651    // and removed the need for implicit instantiation.
2652    switch (Var->getMostRecentDeclaration()->getTemplateSpecializationKind()) {
2653    case TSK_Undeclared:
2654      assert(false && "Cannot instantitiate an undeclared specialization.");
2655    case TSK_ExplicitInstantiationDeclaration:
2656    case TSK_ExplicitInstantiationDefinition:
2657    case TSK_ExplicitSpecialization:
2658      continue;  // No longer need implicit instantiation.
2659    case TSK_ImplicitInstantiation:
2660      break;
2661    }
2662
2663    PrettyStackTraceActionsDecl CrashInfo(DeclPtrTy::make(Var),
2664                                          Var->getLocation(), *this,
2665                                          Context.getSourceManager(),
2666                                          "instantiating static data member "
2667                                          "definition");
2668
2669    InstantiateStaticDataMemberDefinition(/*FIXME:*/Inst.second, Var, true);
2670  }
2671}
2672
2673void Sema::PerformDependentDiagnostics(const DeclContext *Pattern,
2674                       const MultiLevelTemplateArgumentList &TemplateArgs) {
2675  for (DeclContext::ddiag_iterator I = Pattern->ddiag_begin(),
2676         E = Pattern->ddiag_end(); I != E; ++I) {
2677    DependentDiagnostic *DD = *I;
2678
2679    switch (DD->getKind()) {
2680    case DependentDiagnostic::Access:
2681      HandleDependentAccessCheck(*DD, TemplateArgs);
2682      break;
2683    }
2684  }
2685}
2686