SemaTemplateInstantiateDecl.cpp revision d7f37bf8b9a211455c5037df7b7e88e5a9510119 
1//===--- SemaTemplateInstantiateDecl.cpp - C++ Template Decl Instantiation ===/
2//
3//                     The LLVM Compiler Infrastructure
4//
5// This file is distributed under the University of Illinois Open Source
6// License. See LICENSE.TXT for details.
7//===----------------------------------------------------------------------===/
8//
9//  This file implements C++ template instantiation for declarations.
10//
11//===----------------------------------------------------------------------===/
12#include "Sema.h"
13#include "clang/AST/ASTConsumer.h"
14#include "clang/AST/ASTContext.h"
15#include "clang/AST/DeclTemplate.h"
16#include "clang/AST/DeclVisitor.h"
17#include "clang/AST/Expr.h"
18#include "llvm/Support/Compiler.h"
19
20using namespace clang;
21
22namespace {
23  class VISIBILITY_HIDDEN TemplateDeclInstantiator
24    : public DeclVisitor<TemplateDeclInstantiator, Decl *> {
25    Sema &SemaRef;
26    DeclContext *Owner;
27    const TemplateArgumentList &TemplateArgs;
28
29  public:
30    typedef Sema::OwningExprResult OwningExprResult;
31
32    TemplateDeclInstantiator(Sema &SemaRef, DeclContext *Owner,
33                             const TemplateArgumentList &TemplateArgs)
34      : SemaRef(SemaRef), Owner(Owner), TemplateArgs(TemplateArgs) { }
35
36    // FIXME: Once we get closer to completion, replace these manually-written
37    // declarations with automatically-generated ones from
38    // clang/AST/DeclNodes.def.
39    Decl *VisitTranslationUnitDecl(TranslationUnitDecl *D);
40    Decl *VisitNamespaceDecl(NamespaceDecl *D);
41    Decl *VisitTypedefDecl(TypedefDecl *D);
42    Decl *VisitVarDecl(VarDecl *D);
43    Decl *VisitFieldDecl(FieldDecl *D);
44    Decl *VisitStaticAssertDecl(StaticAssertDecl *D);
45    Decl *VisitEnumDecl(EnumDecl *D);
46    Decl *VisitEnumConstantDecl(EnumConstantDecl *D);
47    Decl *VisitCXXRecordDecl(CXXRecordDecl *D);
48    Decl *VisitCXXMethodDecl(CXXMethodDecl *D);
49    Decl *VisitCXXConstructorDecl(CXXConstructorDecl *D);
50    Decl *VisitCXXDestructorDecl(CXXDestructorDecl *D);
51    Decl *VisitCXXConversionDecl(CXXConversionDecl *D);
52    ParmVarDecl *VisitParmVarDecl(ParmVarDecl *D);
53    Decl *VisitOriginalParmVarDecl(OriginalParmVarDecl *D);
54
55    // Base case. FIXME: Remove once we can instantiate everything.
56    Decl *VisitDecl(Decl *) {
57      assert(false && "Template instantiation of unknown declaration kind!");
58      return 0;
59    }
60
61    // Helper functions for instantiating methods.
62    QualType InstantiateFunctionType(FunctionDecl *D,
63                             llvm::SmallVectorImpl<ParmVarDecl *> &Params);
64    bool InitMethodInstantiation(CXXMethodDecl *New, CXXMethodDecl *Tmpl);
65  };
66}
67
68Decl *
69TemplateDeclInstantiator::VisitTranslationUnitDecl(TranslationUnitDecl *D) {
70  assert(false && "Translation units cannot be instantiated");
71  return D;
72}
73
74Decl *
75TemplateDeclInstantiator::VisitNamespaceDecl(NamespaceDecl *D) {
76  assert(false && "Namespaces cannot be instantiated");
77  return D;
78}
79
80Decl *TemplateDeclInstantiator::VisitTypedefDecl(TypedefDecl *D) {
81  bool Invalid = false;
82  QualType T = D->getUnderlyingType();
83  if (T->isDependentType()) {
84    T = SemaRef.InstantiateType(T, TemplateArgs,
85                                D->getLocation(), D->getDeclName());
86    if (T.isNull()) {
87      Invalid = true;
88      T = SemaRef.Context.IntTy;
89    }
90  }
91
92  // Create the new typedef
93  TypedefDecl *Typedef
94    = TypedefDecl::Create(SemaRef.Context, Owner, D->getLocation(),
95                          D->getIdentifier(), T);
96  if (Invalid)
97    Typedef->setInvalidDecl();
98
99  Owner->addDecl(SemaRef.Context, Typedef);
100
101  return Typedef;
102}
103
104Decl *TemplateDeclInstantiator::VisitVarDecl(VarDecl *D) {
105  // Instantiate the type of the declaration
106  QualType T = SemaRef.InstantiateType(D->getType(), TemplateArgs,
107                                       D->getTypeSpecStartLoc(),
108                                       D->getDeclName());
109  if (T.isNull())
110    return 0;
111
112  // Build the instantiated declaration
113  VarDecl *Var = VarDecl::Create(SemaRef.Context, Owner,
114                                 D->getLocation(), D->getIdentifier(),
115                                 T, D->getStorageClass(),
116                                 D->getTypeSpecStartLoc());
117  Var->setThreadSpecified(D->isThreadSpecified());
118  Var->setCXXDirectInitializer(D->hasCXXDirectInitializer());
119  Var->setDeclaredInCondition(D->isDeclaredInCondition());
120
121  // FIXME: In theory, we could have a previous declaration for variables that
122  // are not static data members.
123  bool Redeclaration = false;
124  SemaRef.CheckVariableDeclaration(Var, 0, Redeclaration);
125  Owner->addDecl(SemaRef.Context, Var);
126
127  if (D->getInit()) {
128    OwningExprResult Init
129      = SemaRef.InstantiateExpr(D->getInit(), TemplateArgs);
130    if (Init.isInvalid())
131      Var->setInvalidDecl();
132    else
133      SemaRef.AddInitializerToDecl(Sema::DeclPtrTy::make(Var), move(Init),
134                                   D->hasCXXDirectInitializer());
135  } else {
136    // FIXME: Call ActOnUninitializedDecl? (Not always)
137  }
138
139  return Var;
140}
141
142Decl *TemplateDeclInstantiator::VisitFieldDecl(FieldDecl *D) {
143  bool Invalid = false;
144  QualType T = D->getType();
145  if (T->isDependentType())  {
146    T = SemaRef.InstantiateType(T, TemplateArgs,
147                                D->getLocation(), D->getDeclName());
148    if (!T.isNull() && T->isFunctionType()) {
149      // C++ [temp.arg.type]p3:
150      //   If a declaration acquires a function type through a type
151      //   dependent on a template-parameter and this causes a
152      //   declaration that does not use the syntactic form of a
153      //   function declarator to have function type, the program is
154      //   ill-formed.
155      SemaRef.Diag(D->getLocation(), diag::err_field_instantiates_to_function)
156        << T;
157      T = QualType();
158      Invalid = true;
159    }
160  }
161
162  Expr *BitWidth = D->getBitWidth();
163  if (Invalid)
164    BitWidth = 0;
165  else if (BitWidth) {
166    // The bit-width expression is not potentially evaluated.
167    EnterExpressionEvaluationContext Unevaluated(SemaRef, Action::Unevaluated);
168
169    OwningExprResult InstantiatedBitWidth
170      = SemaRef.InstantiateExpr(BitWidth, TemplateArgs);
171    if (InstantiatedBitWidth.isInvalid()) {
172      Invalid = true;
173      BitWidth = 0;
174    } else
175      BitWidth = InstantiatedBitWidth.takeAs<Expr>();
176  }
177
178  FieldDecl *Field = SemaRef.CheckFieldDecl(D->getDeclName(), T,
179                                            cast<RecordDecl>(Owner),
180                                            D->getLocation(),
181                                            D->isMutable(),
182                                            BitWidth,
183                                            D->getAccess(),
184                                            0);
185  if (Field) {
186    if (Invalid)
187      Field->setInvalidDecl();
188
189    Owner->addDecl(SemaRef.Context, Field);
190  }
191
192  return Field;
193}
194
195Decl *TemplateDeclInstantiator::VisitStaticAssertDecl(StaticAssertDecl *D) {
196  Expr *AssertExpr = D->getAssertExpr();
197
198  // The expression in a static assertion is not potentially evaluated.
199  EnterExpressionEvaluationContext Unevaluated(SemaRef, Action::Unevaluated);
200
201  OwningExprResult InstantiatedAssertExpr
202    = SemaRef.InstantiateExpr(AssertExpr, TemplateArgs);
203  if (InstantiatedAssertExpr.isInvalid())
204    return 0;
205
206  OwningExprResult Message = SemaRef.Clone(D->getMessage());
207  Decl *StaticAssert
208    = SemaRef.ActOnStaticAssertDeclaration(D->getLocation(),
209                                           move(InstantiatedAssertExpr),
210                                           move(Message)).getAs<Decl>();
211  return StaticAssert;
212}
213
214Decl *TemplateDeclInstantiator::VisitEnumDecl(EnumDecl *D) {
215  EnumDecl *Enum = EnumDecl::Create(SemaRef.Context, Owner,
216                                    D->getLocation(), D->getIdentifier(),
217                                    /*PrevDecl=*/0);
218  Enum->setInstantiationOfMemberEnum(D);
219  Enum->setAccess(D->getAccess());
220  Owner->addDecl(SemaRef.Context, Enum);
221  Enum->startDefinition();
222
223  llvm::SmallVector<Sema::DeclPtrTy, 4> Enumerators;
224
225  EnumConstantDecl *LastEnumConst = 0;
226  for (EnumDecl::enumerator_iterator EC = D->enumerator_begin(SemaRef.Context),
227         ECEnd = D->enumerator_end(SemaRef.Context);
228       EC != ECEnd; ++EC) {
229    // The specified value for the enumerator.
230    OwningExprResult Value = SemaRef.Owned((Expr *)0);
231    if (Expr *UninstValue = EC->getInitExpr()) {
232      // The enumerator's value expression is not potentially evaluated.
233      EnterExpressionEvaluationContext Unevaluated(SemaRef,
234                                                   Action::Unevaluated);
235
236      Value = SemaRef.InstantiateExpr(UninstValue, TemplateArgs);
237    }
238
239    // Drop the initial value and continue.
240    bool isInvalid = false;
241    if (Value.isInvalid()) {
242      Value = SemaRef.Owned((Expr *)0);
243      isInvalid = true;
244    }
245
246    EnumConstantDecl *EnumConst
247      = SemaRef.CheckEnumConstant(Enum, LastEnumConst,
248                                  EC->getLocation(), EC->getIdentifier(),
249                                  move(Value));
250
251    if (isInvalid) {
252      if (EnumConst)
253        EnumConst->setInvalidDecl();
254      Enum->setInvalidDecl();
255    }
256
257    if (EnumConst) {
258      Enum->addDecl(SemaRef.Context, EnumConst);
259      Enumerators.push_back(Sema::DeclPtrTy::make(EnumConst));
260      LastEnumConst = EnumConst;
261    }
262  }
263
264  // FIXME: Fixup LBraceLoc and RBraceLoc
265  SemaRef.ActOnEnumBody(Enum->getLocation(), SourceLocation(), SourceLocation(),
266                        Sema::DeclPtrTy::make(Enum),
267                        &Enumerators[0], Enumerators.size());
268
269  return Enum;
270}
271
272Decl *TemplateDeclInstantiator::VisitEnumConstantDecl(EnumConstantDecl *D) {
273  assert(false && "EnumConstantDecls can only occur within EnumDecls.");
274  return 0;
275}
276
277Decl *TemplateDeclInstantiator::VisitCXXRecordDecl(CXXRecordDecl *D) {
278  CXXRecordDecl *PrevDecl = 0;
279  if (D->isInjectedClassName())
280    PrevDecl = cast<CXXRecordDecl>(Owner);
281
282  CXXRecordDecl *Record
283    = CXXRecordDecl::Create(SemaRef.Context, D->getTagKind(), Owner,
284                            D->getLocation(), D->getIdentifier(), PrevDecl);
285  Record->setImplicit(D->isImplicit());
286  Record->setAccess(D->getAccess());
287  if (!D->isInjectedClassName())
288    Record->setInstantiationOfMemberClass(D);
289
290  Owner->addDecl(SemaRef.Context, Record);
291  return Record;
292}
293
294Decl *TemplateDeclInstantiator::VisitCXXMethodDecl(CXXMethodDecl *D) {
295  // Only handle actual methods; we'll deal with constructors,
296  // destructors, etc. separately.
297  if (D->getKind() != Decl::CXXMethod)
298    return 0;
299
300  Sema::LocalInstantiationScope Scope(SemaRef);
301
302  llvm::SmallVector<ParmVarDecl *, 4> Params;
303  QualType T = InstantiateFunctionType(D, Params);
304  if (T.isNull())
305    return 0;
306
307  // Build the instantiated method declaration.
308  CXXRecordDecl *Record = cast<CXXRecordDecl>(Owner);
309  CXXMethodDecl *Method
310    = CXXMethodDecl::Create(SemaRef.Context, Record, D->getLocation(),
311                            D->getDeclName(), T, D->isStatic(),
312                            D->isInline());
313  Method->setInstantiationOfMemberFunction(D);
314
315  // Attach the parameters
316  for (unsigned P = 0; P < Params.size(); ++P)
317    Params[P]->setOwningFunction(Method);
318  Method->setParams(SemaRef.Context, Params.data(), Params.size());
319
320  if (InitMethodInstantiation(Method, D))
321    Method->setInvalidDecl();
322
323  NamedDecl *PrevDecl
324    = SemaRef.LookupQualifiedName(Owner, Method->getDeclName(),
325                                  Sema::LookupOrdinaryName, true);
326  // In C++, the previous declaration we find might be a tag type
327  // (class or enum). In this case, the new declaration will hide the
328  // tag type. Note that this does does not apply if we're declaring a
329  // typedef (C++ [dcl.typedef]p4).
330  if (PrevDecl && PrevDecl->getIdentifierNamespace() == Decl::IDNS_Tag)
331    PrevDecl = 0;
332  bool Redeclaration = false;
333  bool OverloadableAttrRequired = false;
334  SemaRef.CheckFunctionDeclaration(Method, PrevDecl, Redeclaration,
335                                   /*FIXME:*/OverloadableAttrRequired);
336
337  if (!Method->isInvalidDecl() || !PrevDecl)
338    Owner->addDecl(SemaRef.Context, Method);
339  return Method;
340}
341
342Decl *TemplateDeclInstantiator::VisitCXXConstructorDecl(CXXConstructorDecl *D) {
343  Sema::LocalInstantiationScope Scope(SemaRef);
344
345  llvm::SmallVector<ParmVarDecl *, 4> Params;
346  QualType T = InstantiateFunctionType(D, Params);
347  if (T.isNull())
348    return 0;
349
350  // Build the instantiated method declaration.
351  CXXRecordDecl *Record = cast<CXXRecordDecl>(Owner);
352  QualType ClassTy = SemaRef.Context.getTypeDeclType(Record);
353  DeclarationName Name
354    = SemaRef.Context.DeclarationNames.getCXXConstructorName(
355                                 SemaRef.Context.getCanonicalType(ClassTy));
356  CXXConstructorDecl *Constructor
357    = CXXConstructorDecl::Create(SemaRef.Context, Record, D->getLocation(),
358                                 Name, T, D->isExplicit(), D->isInline(),
359                                 false);
360  Constructor->setInstantiationOfMemberFunction(D);
361
362  // Attach the parameters
363  for (unsigned P = 0; P < Params.size(); ++P)
364    Params[P]->setOwningFunction(Constructor);
365  Constructor->setParams(SemaRef.Context, Params.data(), Params.size());
366
367  if (InitMethodInstantiation(Constructor, D))
368    Constructor->setInvalidDecl();
369
370  NamedDecl *PrevDecl
371    = SemaRef.LookupQualifiedName(Owner, Name, Sema::LookupOrdinaryName, true);
372
373  // In C++, the previous declaration we find might be a tag type
374  // (class or enum). In this case, the new declaration will hide the
375  // tag type. Note that this does does not apply if we're declaring a
376  // typedef (C++ [dcl.typedef]p4).
377  if (PrevDecl && PrevDecl->getIdentifierNamespace() == Decl::IDNS_Tag)
378    PrevDecl = 0;
379  bool Redeclaration = false;
380  bool OverloadableAttrRequired = false;
381  SemaRef.CheckFunctionDeclaration(Constructor, PrevDecl, Redeclaration,
382                                   /*FIXME:*/OverloadableAttrRequired);
383
384  Record->addedConstructor(SemaRef.Context, Constructor);
385  Owner->addDecl(SemaRef.Context, Constructor);
386  return Constructor;
387}
388
389Decl *TemplateDeclInstantiator::VisitCXXDestructorDecl(CXXDestructorDecl *D) {
390  Sema::LocalInstantiationScope Scope(SemaRef);
391
392  llvm::SmallVector<ParmVarDecl *, 4> Params;
393  QualType T = InstantiateFunctionType(D, Params);
394  if (T.isNull())
395    return 0;
396  assert(Params.size() == 0 && "Destructor with parameters?");
397
398  // Build the instantiated destructor declaration.
399  CXXRecordDecl *Record = cast<CXXRecordDecl>(Owner);
400  QualType ClassTy =
401    SemaRef.Context.getCanonicalType(SemaRef.Context.getTypeDeclType(Record));
402  CXXDestructorDecl *Destructor
403    = CXXDestructorDecl::Create(SemaRef.Context, Record,
404                                D->getLocation(),
405             SemaRef.Context.DeclarationNames.getCXXDestructorName(ClassTy),
406                                T, D->isInline(), false);
407  Destructor->setInstantiationOfMemberFunction(D);
408  if (InitMethodInstantiation(Destructor, D))
409    Destructor->setInvalidDecl();
410
411  bool Redeclaration = false;
412  bool OverloadableAttrRequired = false;
413  NamedDecl *PrevDecl = 0;
414  SemaRef.CheckFunctionDeclaration(Destructor, PrevDecl, Redeclaration,
415                                   /*FIXME:*/OverloadableAttrRequired);
416  Owner->addDecl(SemaRef.Context, Destructor);
417  return Destructor;
418}
419
420Decl *TemplateDeclInstantiator::VisitCXXConversionDecl(CXXConversionDecl *D) {
421  Sema::LocalInstantiationScope Scope(SemaRef);
422
423  llvm::SmallVector<ParmVarDecl *, 4> Params;
424  QualType T = InstantiateFunctionType(D, Params);
425  if (T.isNull())
426    return 0;
427  assert(Params.size() == 0 && "Destructor with parameters?");
428
429  // Build the instantiated conversion declaration.
430  CXXRecordDecl *Record = cast<CXXRecordDecl>(Owner);
431  QualType ClassTy = SemaRef.Context.getTypeDeclType(Record);
432  QualType ConvTy
433    = SemaRef.Context.getCanonicalType(T->getAsFunctionType()->getResultType());
434  CXXConversionDecl *Conversion
435    = CXXConversionDecl::Create(SemaRef.Context, Record,
436                                D->getLocation(),
437         SemaRef.Context.DeclarationNames.getCXXConversionFunctionName(ConvTy),
438                                T, D->isInline(), D->isExplicit());
439  Conversion->setInstantiationOfMemberFunction(D);
440  if (InitMethodInstantiation(Conversion, D))
441    Conversion->setInvalidDecl();
442
443  bool Redeclaration = false;
444  bool OverloadableAttrRequired = false;
445  NamedDecl *PrevDecl = 0;
446  SemaRef.CheckFunctionDeclaration(Conversion, PrevDecl, Redeclaration,
447                                   /*FIXME:*/OverloadableAttrRequired);
448  Owner->addDecl(SemaRef.Context, Conversion);
449  return Conversion;
450}
451
452ParmVarDecl *TemplateDeclInstantiator::VisitParmVarDecl(ParmVarDecl *D) {
453  QualType OrigT = SemaRef.InstantiateType(D->getOriginalType(), TemplateArgs,
454                                           D->getLocation(), D->getDeclName());
455  if (OrigT.isNull())
456    return 0;
457
458  QualType T = SemaRef.adjustParameterType(OrigT);
459
460  if (D->getDefaultArg()) {
461    // FIXME: Leave a marker for "uninstantiated" default
462    // arguments. They only get instantiated on demand at the call
463    // site.
464    unsigned DiagID = SemaRef.Diags.getCustomDiagID(Diagnostic::Warning,
465        "sorry, dropping default argument during template instantiation");
466    SemaRef.Diag(D->getDefaultArg()->getSourceRange().getBegin(), DiagID)
467      << D->getDefaultArg()->getSourceRange();
468  }
469
470  // Allocate the parameter
471  ParmVarDecl *Param = 0;
472  if (T == OrigT)
473    Param = ParmVarDecl::Create(SemaRef.Context, Owner, D->getLocation(),
474                                D->getIdentifier(), T, D->getStorageClass(),
475                                0);
476  else
477    Param = OriginalParmVarDecl::Create(SemaRef.Context, Owner,
478                                        D->getLocation(), D->getIdentifier(),
479                                        T, OrigT, D->getStorageClass(), 0);
480
481  // Note: we don't try to instantiate function parameters until after
482  // we've instantiated the function's type. Therefore, we don't have
483  // to check for 'void' parameter types here.
484  SemaRef.CurrentInstantiationScope->InstantiatedLocal(D, Param);
485  return Param;
486}
487
488Decl *
489TemplateDeclInstantiator::VisitOriginalParmVarDecl(OriginalParmVarDecl *D) {
490  // Since parameter types can decay either before or after
491  // instantiation, we simply treat OriginalParmVarDecls as
492  // ParmVarDecls the same way, and create one or the other depending
493  // on what happens after template instantiation.
494  return VisitParmVarDecl(D);
495}
496
497Decl *Sema::InstantiateDecl(Decl *D, DeclContext *Owner,
498                            const TemplateArgumentList &TemplateArgs) {
499  TemplateDeclInstantiator Instantiator(*this, Owner, TemplateArgs);
500  return Instantiator.Visit(D);
501}
502
503/// \brief Instantiates the type of the given function, including
504/// instantiating all of the function parameters.
505///
506/// \param D The function that we will be instantiated
507///
508/// \param Params the instantiated parameter declarations
509
510/// \returns the instantiated function's type if successfull, a NULL
511/// type if there was an error.
512QualType
513TemplateDeclInstantiator::InstantiateFunctionType(FunctionDecl *D,
514                              llvm::SmallVectorImpl<ParmVarDecl *> &Params) {
515  bool InvalidDecl = false;
516
517  // Instantiate the function parameters
518  TemplateDeclInstantiator ParamInstantiator(SemaRef, 0, TemplateArgs);
519  llvm::SmallVector<QualType, 4> ParamTys;
520  for (FunctionDecl::param_iterator P = D->param_begin(),
521                                 PEnd = D->param_end();
522       P != PEnd; ++P) {
523    if (ParmVarDecl *PInst = ParamInstantiator.VisitParmVarDecl(*P)) {
524      if (PInst->getType()->isVoidType()) {
525        SemaRef.Diag(PInst->getLocation(), diag::err_param_with_void_type);
526        PInst->setInvalidDecl();
527      }
528      else if (SemaRef.RequireNonAbstractType(PInst->getLocation(),
529                                              PInst->getType(),
530                                              diag::err_abstract_type_in_decl,
531                                              Sema::AbstractParamType))
532        PInst->setInvalidDecl();
533
534      Params.push_back(PInst);
535      ParamTys.push_back(PInst->getType());
536
537      if (PInst->isInvalidDecl())
538        InvalidDecl = true;
539    } else
540      InvalidDecl = true;
541  }
542
543  // FIXME: Deallocate dead declarations.
544  if (InvalidDecl)
545    return QualType();
546
547  const FunctionProtoType *Proto = D->getType()->getAsFunctionProtoType();
548  assert(Proto && "Missing prototype?");
549  QualType ResultType
550    = SemaRef.InstantiateType(Proto->getResultType(), TemplateArgs,
551                              D->getLocation(), D->getDeclName());
552  if (ResultType.isNull())
553    return QualType();
554
555  return SemaRef.BuildFunctionType(ResultType, ParamTys.data(), ParamTys.size(),
556                                   Proto->isVariadic(), Proto->getTypeQuals(),
557                                   D->getLocation(), D->getDeclName());
558}
559
560/// \brief Initializes common fields of an instantiated method
561/// declaration (New) from the corresponding fields of its template
562/// (Tmpl).
563///
564/// \returns true if there was an error
565bool
566TemplateDeclInstantiator::InitMethodInstantiation(CXXMethodDecl *New,
567                                                  CXXMethodDecl *Tmpl) {
568  CXXRecordDecl *Record = cast<CXXRecordDecl>(Owner);
569  New->setAccess(Tmpl->getAccess());
570  if (Tmpl->isVirtualAsWritten()) {
571    New->setVirtualAsWritten(true);
572    Record->setAggregate(false);
573    Record->setPOD(false);
574    Record->setPolymorphic(true);
575  }
576  if (Tmpl->isDeleted())
577    New->setDeleted();
578  if (Tmpl->isPure()) {
579    New->setPure();
580    Record->setAbstract(true);
581  }
582
583  // FIXME: attributes
584  // FIXME: New needs a pointer to Tmpl
585  return false;
586}
587
588/// \brief Instantiate the definition of the given function from its
589/// template.
590///
591/// \param Function the already-instantiated declaration of a
592/// function.
593void Sema::InstantiateFunctionDefinition(SourceLocation PointOfInstantiation,
594                                         FunctionDecl *Function) {
595  // FIXME: make this work for function template specializations, too.
596
597  if (Function->isInvalidDecl())
598    return;
599
600  assert(!Function->getBody(Context) && "Already instantiated!");
601
602  // Find the function body that we'll be substituting.
603  const FunctionDecl *PatternDecl
604    = Function->getInstantiatedFromMemberFunction();
605  Stmt *Pattern = 0;
606  if (PatternDecl)
607    Pattern = PatternDecl->getBody(Context, PatternDecl);
608
609  if (!Pattern)
610    return;
611
612  InstantiatingTemplate Inst(*this, PointOfInstantiation, Function);
613  if (Inst)
614    return;
615
616  ActOnStartOfFunctionDef(0, DeclPtrTy::make(Function));
617
618  // Introduce a new scope where local variable instantiations will be
619  // recorded.
620  LocalInstantiationScope Scope(*this);
621
622  // Introduce the instantiated function parameters into the local
623  // instantiation scope.
624  for (unsigned I = 0, N = PatternDecl->getNumParams(); I != N; ++I)
625    Scope.InstantiatedLocal(PatternDecl->getParamDecl(I),
626                            Function->getParamDecl(I));
627
628  // Enter the scope of this instantiation. We don't use
629  // PushDeclContext because we don't have a scope.
630  DeclContext *PreviousContext = CurContext;
631  CurContext = Function;
632
633  // Instantiate the function body.
634  OwningStmtResult Body
635    = InstantiateStmt(Pattern, getTemplateInstantiationArgs(Function));
636
637  ActOnFinishFunctionBody(DeclPtrTy::make(Function), move(Body),
638                          /*IsInstantiation=*/true);
639
640  CurContext = PreviousContext;
641
642  DeclGroupRef DG(Function);
643  Consumer.HandleTopLevelDecl(DG);
644}
645
646/// \brief Instantiate the definition of the given variable from its
647/// template.
648///
649/// \param Var the already-instantiated declaration of a variable.
650void Sema::InstantiateVariableDefinition(VarDecl *Var) {
651  // FIXME: Implement this!
652}
653
654static bool isInstantiationOf(ASTContext &Ctx, NamedDecl *D, Decl *Other) {
655  if (D->getKind() != Other->getKind())
656    return false;
657
658  if (CXXRecordDecl *Record = dyn_cast<CXXRecordDecl>(Other))
659    return Ctx.getCanonicalDecl(Record->getInstantiatedFromMemberClass())
660             == Ctx.getCanonicalDecl(D);
661
662  if (FunctionDecl *Function = dyn_cast<FunctionDecl>(Other))
663    return Ctx.getCanonicalDecl(Function->getInstantiatedFromMemberFunction())
664             == Ctx.getCanonicalDecl(D);
665
666  if (EnumDecl *Enum = dyn_cast<EnumDecl>(Other))
667    return Ctx.getCanonicalDecl(Enum->getInstantiatedFromMemberEnum())
668             == Ctx.getCanonicalDecl(D);
669
670  // FIXME: How can we find instantiations of anonymous unions?
671
672  return D->getDeclName() && isa<NamedDecl>(Other) &&
673    D->getDeclName() == cast<NamedDecl>(Other)->getDeclName();
674}
675
676template<typename ForwardIterator>
677static NamedDecl *findInstantiationOf(ASTContext &Ctx,
678                                      NamedDecl *D,
679                                      ForwardIterator first,
680                                      ForwardIterator last) {
681  for (; first != last; ++first)
682    if (isInstantiationOf(Ctx, D, *first))
683      return cast<NamedDecl>(*first);
684
685  return 0;
686}
687
688/// \brief Find the instantiation of the given declaration within the
689/// current instantiation.
690///
691/// This routine is intended to be used when \p D is a declaration
692/// referenced from within a template, that needs to mapped into the
693/// corresponding declaration within an instantiation. For example,
694/// given:
695///
696/// \code
697/// template<typename T>
698/// struct X {
699///   enum Kind {
700///     KnownValue = sizeof(T)
701///   };
702///
703///   bool getKind() const { return KnownValue; }
704/// };
705///
706/// template struct X<int>;
707/// \endcode
708///
709/// In the instantiation of X<int>::getKind(), we need to map the
710/// EnumConstantDecl for KnownValue (which refers to
711/// X<T>::<Kind>::KnownValue) to its instantiation
712/// (X<int>::<Kind>::KnownValue). InstantiateCurrentDeclRef() performs
713/// this mapping from within the instantiation of X<int>.
714NamedDecl * Sema::InstantiateCurrentDeclRef(NamedDecl *D) {
715  DeclContext *ParentDC = D->getDeclContext();
716  if (isa<ParmVarDecl>(D) || ParentDC->isFunctionOrMethod()) {
717    // D is a local of some kind. Look into the map of local
718    // declarations to their instantiations.
719    return cast<NamedDecl>(CurrentInstantiationScope->getInstantiationOf(D));
720  }
721
722  if (NamedDecl *ParentDecl = dyn_cast<NamedDecl>(ParentDC)) {
723    ParentDecl = InstantiateCurrentDeclRef(ParentDecl);
724    if (!ParentDecl)
725      return 0;
726
727    ParentDC = cast<DeclContext>(ParentDecl);
728  }
729
730  if (ParentDC != D->getDeclContext()) {
731    // We performed some kind of instantiation in the parent context,
732    // so now we need to look into the instantiated parent context to
733    // find the instantiation of the declaration D.
734    NamedDecl *Result = 0;
735    if (D->getDeclName()) {
736      DeclContext::lookup_result Found
737        = ParentDC->lookup(Context, D->getDeclName());
738      Result = findInstantiationOf(Context, D, Found.first, Found.second);
739    } else {
740      // Since we don't have a name for the entity we're looking for,
741      // our only option is to walk through all of the declarations to
742      // find that name. This will occur in a few cases:
743      //
744      //   - anonymous struct/union within a template
745      //   - unnamed class/struct/union/enum within a template
746      //
747      // FIXME: Find a better way to find these instantiations!
748      Result = findInstantiationOf(Context, D,
749                                   ParentDC->decls_begin(Context),
750                                   ParentDC->decls_end(Context));
751    }
752    assert(Result && "Unable to find instantiation of declaration!");
753    D = Result;
754  }
755
756  if (CXXRecordDecl *Record = dyn_cast<CXXRecordDecl>(D))
757    if (ClassTemplateDecl *ClassTemplate
758          = Record->getDescribedClassTemplate()) {
759      // When the declaration D was parsed, it referred to the current
760      // instantiation. Therefore, look through the current context,
761      // which contains actual instantiations, to find the
762      // instantiation of the "current instantiation" that D refers
763      // to. Alternatively, we could just instantiate the
764      // injected-class-name with the current template arguments, but
765      // such an instantiation is far more expensive.
766      for (DeclContext *DC = CurContext; !DC->isFileContext();
767           DC = DC->getParent()) {
768        if (ClassTemplateSpecializationDecl *Spec
769              = dyn_cast<ClassTemplateSpecializationDecl>(DC))
770          if (Context.getCanonicalDecl(Spec->getSpecializedTemplate())
771              == Context.getCanonicalDecl(ClassTemplate))
772            return Spec;
773      }
774
775      assert(false &&
776             "Unable to find declaration for the current instantiation");
777    }
778
779  return D;
780}
781
782/// \brief Performs template instantiation for all implicit template
783/// instantiations we have seen until this point.
784void Sema::PerformPendingImplicitInstantiations() {
785  while (!PendingImplicitInstantiations.empty()) {
786    PendingImplicitInstantiation Inst = PendingImplicitInstantiations.front();
787    PendingImplicitInstantiations.pop();
788
789    if (FunctionDecl *Function = dyn_cast<FunctionDecl>(Inst.first))
790      if (!Function->getBody(Context))
791        InstantiateFunctionDefinition(/*FIXME:*/Inst.second, Function);
792
793    // FIXME: instantiation static member variables
794  }
795}
796