SemaTemplateInstantiateDecl.cpp revision 8dbc3c64965f99e48830885835b7d2fc26ec3cf5 
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  return Typedef;
101}
102
103Decl *TemplateDeclInstantiator::VisitVarDecl(VarDecl *D) {
104  // Instantiate the type of the declaration
105  QualType T = SemaRef.InstantiateType(D->getType(), TemplateArgs,
106                                       D->getTypeSpecStartLoc(),
107                                       D->getDeclName());
108  if (T.isNull())
109    return 0;
110
111  // Build the instantiated declaration
112  VarDecl *Var = VarDecl::Create(SemaRef.Context, Owner,
113                                 D->getLocation(), D->getIdentifier(),
114                                 T, D->getStorageClass(),
115                                 D->getTypeSpecStartLoc());
116  Var->setThreadSpecified(D->isThreadSpecified());
117  Var->setCXXDirectInitializer(D->hasCXXDirectInitializer());
118  Var->setDeclaredInCondition(D->isDeclaredInCondition());
119
120  // FIXME: In theory, we could have a previous declaration for variables that
121  // are not static data members.
122  bool Redeclaration = false;
123  SemaRef.CheckVariableDeclaration(Var, 0, Redeclaration);
124  Owner->addDecl(SemaRef.Context, Var);
125
126  if (D->getInit()) {
127    OwningExprResult Init
128      = SemaRef.InstantiateExpr(D->getInit(), TemplateArgs);
129    if (Init.isInvalid())
130      Var->setInvalidDecl();
131    else
132      SemaRef.AddInitializerToDecl(Sema::DeclPtrTy::make(Var), move(Init),
133                                   D->hasCXXDirectInitializer());
134  } else {
135    // FIXME: Call ActOnUninitializedDecl? (Not always)
136  }
137
138  return Var;
139}
140
141Decl *TemplateDeclInstantiator::VisitFieldDecl(FieldDecl *D) {
142  bool Invalid = false;
143  QualType T = D->getType();
144  if (T->isDependentType())  {
145    T = SemaRef.InstantiateType(T, TemplateArgs,
146                                D->getLocation(), D->getDeclName());
147    if (!T.isNull() && T->isFunctionType()) {
148      // C++ [temp.arg.type]p3:
149      //   If a declaration acquires a function type through a type
150      //   dependent on a template-parameter and this causes a
151      //   declaration that does not use the syntactic form of a
152      //   function declarator to have function type, the program is
153      //   ill-formed.
154      SemaRef.Diag(D->getLocation(), diag::err_field_instantiates_to_function)
155        << T;
156      T = QualType();
157      Invalid = true;
158    }
159  }
160
161  Expr *BitWidth = D->getBitWidth();
162  if (Invalid)
163    BitWidth = 0;
164  else if (BitWidth) {
165    OwningExprResult InstantiatedBitWidth
166      = SemaRef.InstantiateExpr(BitWidth, TemplateArgs);
167    if (InstantiatedBitWidth.isInvalid()) {
168      Invalid = true;
169      BitWidth = 0;
170    } else
171      BitWidth = InstantiatedBitWidth.takeAs<Expr>();
172  }
173
174  FieldDecl *Field = SemaRef.CheckFieldDecl(D->getDeclName(), T,
175                                            cast<RecordDecl>(Owner),
176                                            D->getLocation(),
177                                            D->isMutable(),
178                                            BitWidth,
179                                            D->getAccess(),
180                                            0);
181  if (Field) {
182    if (Invalid)
183      Field->setInvalidDecl();
184
185    Owner->addDecl(SemaRef.Context, Field);
186  }
187
188  return Field;
189}
190
191Decl *TemplateDeclInstantiator::VisitStaticAssertDecl(StaticAssertDecl *D) {
192  Expr *AssertExpr = D->getAssertExpr();
193
194  OwningExprResult InstantiatedAssertExpr
195    = SemaRef.InstantiateExpr(AssertExpr, TemplateArgs);
196  if (InstantiatedAssertExpr.isInvalid())
197    return 0;
198
199  OwningExprResult Message = SemaRef.Clone(D->getMessage());
200  Decl *StaticAssert
201    = SemaRef.ActOnStaticAssertDeclaration(D->getLocation(),
202                                           move(InstantiatedAssertExpr),
203                                           move(Message)).getAs<Decl>();
204  return StaticAssert;
205}
206
207Decl *TemplateDeclInstantiator::VisitEnumDecl(EnumDecl *D) {
208  EnumDecl *Enum = EnumDecl::Create(SemaRef.Context, Owner,
209                                    D->getLocation(), D->getIdentifier(),
210                                    /*PrevDecl=*/0);
211  Enum->setInstantiationOfMemberEnum(D);
212  Enum->setAccess(D->getAccess());
213  Owner->addDecl(SemaRef.Context, Enum);
214  Enum->startDefinition();
215
216  llvm::SmallVector<Sema::DeclPtrTy, 16> Enumerators;
217
218  EnumConstantDecl *LastEnumConst = 0;
219  for (EnumDecl::enumerator_iterator EC = D->enumerator_begin(SemaRef.Context),
220         ECEnd = D->enumerator_end(SemaRef.Context);
221       EC != ECEnd; ++EC) {
222    // The specified value for the enumerator.
223    OwningExprResult Value = SemaRef.Owned((Expr *)0);
224    if (Expr *UninstValue = EC->getInitExpr())
225      Value = SemaRef.InstantiateExpr(UninstValue, TemplateArgs);
226
227    // Drop the initial value and continue.
228    bool isInvalid = false;
229    if (Value.isInvalid()) {
230      Value = SemaRef.Owned((Expr *)0);
231      isInvalid = true;
232    }
233
234    EnumConstantDecl *EnumConst
235      = SemaRef.CheckEnumConstant(Enum, LastEnumConst,
236                                  EC->getLocation(), EC->getIdentifier(),
237                                  move(Value));
238
239    if (isInvalid) {
240      if (EnumConst)
241        EnumConst->setInvalidDecl();
242      Enum->setInvalidDecl();
243    }
244
245    if (EnumConst) {
246      Enum->addDecl(SemaRef.Context, EnumConst);
247      Enumerators.push_back(Sema::DeclPtrTy::make(EnumConst));
248      LastEnumConst = EnumConst;
249    }
250  }
251
252  // FIXME: Fixup LBraceLoc and RBraceLoc
253  SemaRef.ActOnEnumBody(Enum->getLocation(), SourceLocation(), SourceLocation(),
254                        Sema::DeclPtrTy::make(Enum),
255                        &Enumerators[0], Enumerators.size());
256
257  return Enum;
258}
259
260Decl *TemplateDeclInstantiator::VisitEnumConstantDecl(EnumConstantDecl *D) {
261  assert(false && "EnumConstantDecls can only occur within EnumDecls.");
262  return 0;
263}
264
265Decl *TemplateDeclInstantiator::VisitCXXRecordDecl(CXXRecordDecl *D) {
266  CXXRecordDecl *PrevDecl = 0;
267  if (D->isInjectedClassName())
268    PrevDecl = cast<CXXRecordDecl>(Owner);
269
270  CXXRecordDecl *Record
271    = CXXRecordDecl::Create(SemaRef.Context, D->getTagKind(), Owner,
272                            D->getLocation(), D->getIdentifier(), PrevDecl);
273  Record->setImplicit(D->isImplicit());
274  Record->setAccess(D->getAccess());
275  if (!D->isInjectedClassName())
276    Record->setInstantiationOfMemberClass(D);
277
278  Owner->addDecl(SemaRef.Context, Record);
279  return Record;
280}
281
282Decl *TemplateDeclInstantiator::VisitCXXMethodDecl(CXXMethodDecl *D) {
283  // Only handle actual methods; we'll deal with constructors,
284  // destructors, etc. separately.
285  if (D->getKind() != Decl::CXXMethod)
286    return 0;
287
288  Sema::LocalInstantiationScope Scope(SemaRef);
289
290  llvm::SmallVector<ParmVarDecl *, 16> Params;
291  QualType T = InstantiateFunctionType(D, Params);
292  if (T.isNull())
293    return 0;
294
295  // Build the instantiated method declaration.
296  CXXRecordDecl *Record = cast<CXXRecordDecl>(Owner);
297  CXXMethodDecl *Method
298    = CXXMethodDecl::Create(SemaRef.Context, Record, D->getLocation(),
299                            D->getDeclName(), T, D->isStatic(),
300                            D->isInline());
301  Method->setInstantiationOfMemberFunction(D);
302
303  // Attach the parameters
304  for (unsigned P = 0; P < Params.size(); ++P)
305    Params[P]->setOwningFunction(Method);
306  Method->setParams(SemaRef.Context, Params.data(), Params.size());
307
308  if (InitMethodInstantiation(Method, D))
309    Method->setInvalidDecl();
310
311  NamedDecl *PrevDecl
312    = SemaRef.LookupQualifiedName(Owner, Method->getDeclName(),
313                                  Sema::LookupOrdinaryName, true);
314  // In C++, the previous declaration we find might be a tag type
315  // (class or enum). In this case, the new declaration will hide the
316  // tag type. Note that this does does not apply if we're declaring a
317  // typedef (C++ [dcl.typedef]p4).
318  if (PrevDecl && PrevDecl->getIdentifierNamespace() == Decl::IDNS_Tag)
319    PrevDecl = 0;
320  bool Redeclaration = false;
321  bool OverloadableAttrRequired = false;
322  SemaRef.CheckFunctionDeclaration(Method, PrevDecl, Redeclaration,
323                                   /*FIXME:*/OverloadableAttrRequired);
324
325  if (!Method->isInvalidDecl() || !PrevDecl)
326    Owner->addDecl(SemaRef.Context, Method);
327  return Method;
328}
329
330Decl *TemplateDeclInstantiator::VisitCXXConstructorDecl(CXXConstructorDecl *D) {
331  Sema::LocalInstantiationScope Scope(SemaRef);
332
333  llvm::SmallVector<ParmVarDecl *, 16> Params;
334  QualType T = InstantiateFunctionType(D, Params);
335  if (T.isNull())
336    return 0;
337
338  // Build the instantiated method declaration.
339  CXXRecordDecl *Record = cast<CXXRecordDecl>(Owner);
340  QualType ClassTy = SemaRef.Context.getTypeDeclType(Record);
341  DeclarationName Name
342    = SemaRef.Context.DeclarationNames.getCXXConstructorName(
343                                 SemaRef.Context.getCanonicalType(ClassTy));
344  CXXConstructorDecl *Constructor
345    = CXXConstructorDecl::Create(SemaRef.Context, Record, D->getLocation(),
346                                 Name, T, D->isExplicit(), D->isInline(),
347                                 false);
348  Constructor->setInstantiationOfMemberFunction(D);
349
350  // Attach the parameters
351  for (unsigned P = 0; P < Params.size(); ++P)
352    Params[P]->setOwningFunction(Constructor);
353  Constructor->setParams(SemaRef.Context, Params.data(), Params.size());
354
355  if (InitMethodInstantiation(Constructor, D))
356    Constructor->setInvalidDecl();
357
358  NamedDecl *PrevDecl
359    = SemaRef.LookupQualifiedName(Owner, Name, Sema::LookupOrdinaryName, true);
360
361  // In C++, the previous declaration we find might be a tag type
362  // (class or enum). In this case, the new declaration will hide the
363  // tag type. Note that this does does not apply if we're declaring a
364  // typedef (C++ [dcl.typedef]p4).
365  if (PrevDecl && PrevDecl->getIdentifierNamespace() == Decl::IDNS_Tag)
366    PrevDecl = 0;
367  bool Redeclaration = false;
368  bool OverloadableAttrRequired = false;
369  SemaRef.CheckFunctionDeclaration(Constructor, PrevDecl, Redeclaration,
370                                   /*FIXME:*/OverloadableAttrRequired);
371
372  Record->addedConstructor(SemaRef.Context, Constructor);
373  Owner->addDecl(SemaRef.Context, Constructor);
374  return Constructor;
375}
376
377Decl *TemplateDeclInstantiator::VisitCXXDestructorDecl(CXXDestructorDecl *D) {
378  Sema::LocalInstantiationScope Scope(SemaRef);
379
380  llvm::SmallVector<ParmVarDecl *, 16> Params;
381  QualType T = InstantiateFunctionType(D, Params);
382  if (T.isNull())
383    return 0;
384  assert(Params.size() == 0 && "Destructor with parameters?");
385
386  // Build the instantiated destructor declaration.
387  CXXRecordDecl *Record = cast<CXXRecordDecl>(Owner);
388  QualType ClassTy =
389    SemaRef.Context.getCanonicalType(SemaRef.Context.getTypeDeclType(Record));
390  CXXDestructorDecl *Destructor
391    = CXXDestructorDecl::Create(SemaRef.Context, Record,
392                                D->getLocation(),
393             SemaRef.Context.DeclarationNames.getCXXDestructorName(ClassTy),
394                                T, D->isInline(), false);
395  Destructor->setInstantiationOfMemberFunction(D);
396  if (InitMethodInstantiation(Destructor, D))
397    Destructor->setInvalidDecl();
398
399  bool Redeclaration = false;
400  bool OverloadableAttrRequired = false;
401  NamedDecl *PrevDecl = 0;
402  SemaRef.CheckFunctionDeclaration(Destructor, PrevDecl, Redeclaration,
403                                   /*FIXME:*/OverloadableAttrRequired);
404  Owner->addDecl(SemaRef.Context, Destructor);
405  return Destructor;
406}
407
408Decl *TemplateDeclInstantiator::VisitCXXConversionDecl(CXXConversionDecl *D) {
409  Sema::LocalInstantiationScope Scope(SemaRef);
410
411  llvm::SmallVector<ParmVarDecl *, 16> Params;
412  QualType T = InstantiateFunctionType(D, Params);
413  if (T.isNull())
414    return 0;
415  assert(Params.size() == 0 && "Destructor with parameters?");
416
417  // Build the instantiated conversion declaration.
418  CXXRecordDecl *Record = cast<CXXRecordDecl>(Owner);
419  QualType ClassTy = SemaRef.Context.getTypeDeclType(Record);
420  QualType ConvTy
421    = SemaRef.Context.getCanonicalType(T->getAsFunctionType()->getResultType());
422  CXXConversionDecl *Conversion
423    = CXXConversionDecl::Create(SemaRef.Context, Record,
424                                D->getLocation(),
425         SemaRef.Context.DeclarationNames.getCXXConversionFunctionName(ConvTy),
426                                T, D->isInline(), D->isExplicit());
427  Conversion->setInstantiationOfMemberFunction(D);
428  if (InitMethodInstantiation(Conversion, D))
429    Conversion->setInvalidDecl();
430
431  bool Redeclaration = false;
432  bool OverloadableAttrRequired = false;
433  NamedDecl *PrevDecl = 0;
434  SemaRef.CheckFunctionDeclaration(Conversion, PrevDecl, Redeclaration,
435                                   /*FIXME:*/OverloadableAttrRequired);
436  Owner->addDecl(SemaRef.Context, Conversion);
437  return Conversion;
438}
439
440ParmVarDecl *TemplateDeclInstantiator::VisitParmVarDecl(ParmVarDecl *D) {
441  QualType OrigT = SemaRef.InstantiateType(D->getOriginalType(), TemplateArgs,
442                                           D->getLocation(), D->getDeclName());
443  if (OrigT.isNull())
444    return 0;
445
446  QualType T = SemaRef.adjustParameterType(OrigT);
447
448  if (D->getDefaultArg()) {
449    // FIXME: Leave a marker for "uninstantiated" default
450    // arguments. They only get instantiated on demand at the call
451    // site.
452    unsigned DiagID = SemaRef.Diags.getCustomDiagID(Diagnostic::Warning,
453        "sorry, dropping default argument during template instantiation");
454    SemaRef.Diag(D->getDefaultArg()->getSourceRange().getBegin(), DiagID)
455      << D->getDefaultArg()->getSourceRange();
456  }
457
458  // Allocate the parameter
459  ParmVarDecl *Param = 0;
460  if (T == OrigT)
461    Param = ParmVarDecl::Create(SemaRef.Context, Owner, D->getLocation(),
462                                D->getIdentifier(), T, D->getStorageClass(),
463                                0);
464  else
465    Param = OriginalParmVarDecl::Create(SemaRef.Context, Owner,
466                                        D->getLocation(), D->getIdentifier(),
467                                        T, OrigT, D->getStorageClass(), 0);
468
469  // Note: we don't try to instantiate function parameters until after
470  // we've instantiated the function's type. Therefore, we don't have
471  // to check for 'void' parameter types here.
472  SemaRef.CurrentInstantiationScope->InstantiatedLocal(D, Param);
473  return Param;
474}
475
476Decl *
477TemplateDeclInstantiator::VisitOriginalParmVarDecl(OriginalParmVarDecl *D) {
478  // Since parameter types can decay either before or after
479  // instantiation, we simply treat OriginalParmVarDecls as
480  // ParmVarDecls the same way, and create one or the other depending
481  // on what happens after template instantiation.
482  return VisitParmVarDecl(D);
483}
484
485Decl *Sema::InstantiateDecl(Decl *D, DeclContext *Owner,
486                            const TemplateArgumentList &TemplateArgs) {
487  TemplateDeclInstantiator Instantiator(*this, Owner, TemplateArgs);
488  return Instantiator.Visit(D);
489}
490
491/// \brief Instantiates the type of the given function, including
492/// instantiating all of the function parameters.
493///
494/// \param D The function that we will be instantiated
495///
496/// \param Params the instantiated parameter declarations
497
498/// \returns the instantiated function's type if successfull, a NULL
499/// type if there was an error.
500QualType
501TemplateDeclInstantiator::InstantiateFunctionType(FunctionDecl *D,
502                              llvm::SmallVectorImpl<ParmVarDecl *> &Params) {
503  bool InvalidDecl = false;
504
505  // Instantiate the function parameters
506  TemplateDeclInstantiator ParamInstantiator(SemaRef, 0, TemplateArgs);
507  llvm::SmallVector<QualType, 16> ParamTys;
508  for (FunctionDecl::param_iterator P = D->param_begin(),
509                                 PEnd = D->param_end();
510       P != PEnd; ++P) {
511    if (ParmVarDecl *PInst = ParamInstantiator.VisitParmVarDecl(*P)) {
512      if (PInst->getType()->isVoidType()) {
513        SemaRef.Diag(PInst->getLocation(), diag::err_param_with_void_type);
514        PInst->setInvalidDecl();
515      }
516      else if (SemaRef.RequireNonAbstractType(PInst->getLocation(),
517                                              PInst->getType(),
518                                              diag::err_abstract_type_in_decl,
519                                              Sema::AbstractParamType))
520        PInst->setInvalidDecl();
521
522      Params.push_back(PInst);
523      ParamTys.push_back(PInst->getType());
524
525      if (PInst->isInvalidDecl())
526        InvalidDecl = true;
527    } else
528      InvalidDecl = true;
529  }
530
531  // FIXME: Deallocate dead declarations.
532  if (InvalidDecl)
533    return QualType();
534
535  const FunctionProtoType *Proto = D->getType()->getAsFunctionProtoType();
536  assert(Proto && "Missing prototype?");
537  QualType ResultType
538    = SemaRef.InstantiateType(Proto->getResultType(), TemplateArgs,
539                              D->getLocation(), D->getDeclName());
540  if (ResultType.isNull())
541    return QualType();
542
543  return SemaRef.BuildFunctionType(ResultType, ParamTys.data(), ParamTys.size(),
544                                   Proto->isVariadic(), Proto->getTypeQuals(),
545                                   D->getLocation(), D->getDeclName());
546}
547
548/// \brief Initializes common fields of an instantiated method
549/// declaration (New) from the corresponding fields of its template
550/// (Tmpl).
551///
552/// \returns true if there was an error
553bool
554TemplateDeclInstantiator::InitMethodInstantiation(CXXMethodDecl *New,
555                                                  CXXMethodDecl *Tmpl) {
556  CXXRecordDecl *Record = cast<CXXRecordDecl>(Owner);
557  New->setAccess(Tmpl->getAccess());
558  if (Tmpl->isVirtualAsWritten()) {
559    New->setVirtualAsWritten(true);
560    Record->setAggregate(false);
561    Record->setPOD(false);
562    Record->setPolymorphic(true);
563  }
564  if (Tmpl->isDeleted())
565    New->setDeleted();
566  if (Tmpl->isPure()) {
567    New->setPure();
568    Record->setAbstract(true);
569  }
570
571  // FIXME: attributes
572  // FIXME: New needs a pointer to Tmpl
573  return false;
574}
575
576/// \brief Instantiate the definition of the given function from its
577/// template.
578///
579/// \param Function the already-instantiated declaration of a
580/// function.
581void Sema::InstantiateFunctionDefinition(SourceLocation PointOfInstantiation,
582                                         FunctionDecl *Function) {
583  // FIXME: make this work for function template specializations, too.
584
585  if (Function->isInvalidDecl())
586    return;
587
588  // Find the function body that we'll be substituting.
589  const FunctionDecl *PatternDecl
590    = Function->getInstantiatedFromMemberFunction();
591  Stmt *Pattern = 0;
592  if (PatternDecl)
593    Pattern = PatternDecl->getBody(Context, PatternDecl);
594
595  if (!Pattern)
596    return;
597
598  InstantiatingTemplate Inst(*this, PointOfInstantiation, Function);
599  if (Inst)
600    return;
601
602  ActOnStartOfFunctionDef(0, DeclPtrTy::make(Function));
603
604  // Introduce a new scope where local variable instantiations will be
605  // recorded.
606  LocalInstantiationScope Scope(*this);
607
608  // Introduce the instantiated function parameters into the local
609  // instantiation scope.
610  for (unsigned I = 0, N = PatternDecl->getNumParams(); I != N; ++I)
611    Scope.InstantiatedLocal(PatternDecl->getParamDecl(I),
612                            Function->getParamDecl(I));
613
614  // Enter the scope of this instantiation. We don't use
615  // PushDeclContext because we don't have a scope.
616  DeclContext *PreviousContext = CurContext;
617  CurContext = Function;
618
619  // Instantiate the function body.
620  OwningStmtResult Body
621    = InstantiateStmt(Pattern, getTemplateInstantiationArgs(Function));
622
623  ActOnFinishFunctionBody(DeclPtrTy::make(Function), move(Body),
624                          /*IsInstantiation=*/true);
625
626  CurContext = PreviousContext;
627
628  DeclGroupRef DG(Function);
629  Consumer.HandleTopLevelDecl(DG);
630}
631
632/// \brief Instantiate the definition of the given variable from its
633/// template.
634///
635/// \param Var the already-instantiated declaration of a variable.
636void Sema::InstantiateVariableDefinition(VarDecl *Var) {
637  // FIXME: Implement this!
638}
639
640static bool isInstantiationOf(ASTContext &Ctx, NamedDecl *D, Decl *Other) {
641  if (D->getKind() != Other->getKind())
642    return false;
643
644  if (CXXRecordDecl *Record = dyn_cast<CXXRecordDecl>(Other))
645    return Ctx.getCanonicalDecl(Record->getInstantiatedFromMemberClass())
646             == Ctx.getCanonicalDecl(D);
647
648  if (FunctionDecl *Function = dyn_cast<FunctionDecl>(Other))
649    return Ctx.getCanonicalDecl(Function->getInstantiatedFromMemberFunction())
650             == Ctx.getCanonicalDecl(D);
651
652  if (EnumDecl *Enum = dyn_cast<EnumDecl>(Other))
653    return Ctx.getCanonicalDecl(Enum->getInstantiatedFromMemberEnum())
654             == Ctx.getCanonicalDecl(D);
655
656  // FIXME: How can we find instantiations of anonymous unions?
657
658  return D->getDeclName() && isa<NamedDecl>(Other) &&
659    D->getDeclName() == cast<NamedDecl>(Other)->getDeclName();
660}
661
662template<typename ForwardIterator>
663static NamedDecl *findInstantiationOf(ASTContext &Ctx,
664                                      NamedDecl *D,
665                                      ForwardIterator first,
666                                      ForwardIterator last) {
667  for (; first != last; ++first)
668    if (isInstantiationOf(Ctx, D, *first))
669      return cast<NamedDecl>(*first);
670
671  return 0;
672}
673
674/// \brief Find the instantiation of the given declaration with the
675/// given template arguments.
676///
677/// This routine is intended to be used when \p D is a declaration
678/// referenced from within a template, that needs to mapped into the
679/// corresponding declaration within an instantiation. For example,
680/// given:
681///
682/// \code
683/// template<typename T>
684/// struct X {
685///   enum Kind {
686///     KnownValue = sizeof(T)
687///   };
688///
689///   bool getKind() const { return KnownValue; }
690/// };
691///
692/// template struct X<int>;
693/// \endcode
694///
695/// In the instantiation of X<int>::getKind(), we need to map the
696/// EnumConstantDecl for KnownValue (which refers to
697/// X<T>::<Kind>::KnownValue) to its instantiation
698/// (X<int>::<Kind>::KnownValue). InstantiateDeclRef() performs this
699/// mapping, given the template arguments 'int'.
700NamedDecl *
701Sema::InstantiateDeclRef(NamedDecl *D, const TemplateArgumentList &TemplateArgs) {
702  DeclContext *ParentDC = D->getDeclContext();
703  if (isa<ParmVarDecl>(D) || ParentDC->isFunctionOrMethod()) {
704    // D is a local of some kind. Look into the map of local
705    // declarations to their instantiations.
706    return cast<NamedDecl>(CurrentInstantiationScope->getInstantiationOf(D));
707  }
708
709  if (NamedDecl *ParentDecl = dyn_cast<NamedDecl>(ParentDC)) {
710    ParentDecl = InstantiateDeclRef(ParentDecl, TemplateArgs);
711    if (!ParentDecl)
712      return 0;
713
714    ParentDC = cast<DeclContext>(ParentDecl);
715  }
716
717  if (ParentDC != D->getDeclContext()) {
718    // We performed some kind of instantiation in the parent context,
719    // so now we need to look into the instantiated parent context to
720    // find the instantiation of the declaration D.
721    NamedDecl *Result = 0;
722    if (D->getDeclName()) {
723      DeclContext::lookup_result Found
724        = ParentDC->lookup(Context, D->getDeclName());
725      Result = findInstantiationOf(Context, D, Found.first, Found.second);
726    } else {
727      // Since we don't have a name for the entity we're looking for,
728      // our only option is to walk through all of the declarations to
729      // find that name. This will occur in a few cases:
730      //
731      //   - anonymous struct/union within a template
732      //   - unnamed class/struct/union/enum within a template
733      //
734      // FIXME: Find a better way to find these instantiations!
735      Result = findInstantiationOf(Context, D,
736                                   ParentDC->decls_begin(Context),
737                                   ParentDC->decls_end(Context));
738    }
739    assert(Result && "Unable to find instantiation of declaration!");
740    D = Result;
741  }
742
743  // D itself might be a class template that we need to instantiate
744  // with the given template arguments.
745  if (CXXRecordDecl *Record = dyn_cast<CXXRecordDecl>(D))
746    if (ClassTemplateDecl *ClassTemplate = Record->getDescribedClassTemplate()) {
747      QualType InjectedClassName
748        = ClassTemplate->getInjectedClassNameType(Context);
749      QualType InstantiatedType = InstantiateType(InjectedClassName,
750                                                  TemplateArgs,
751                                                  Record->getLocation(),
752                                                  Record->getDeclName());
753      if (InstantiatedType.isNull())
754        return 0;
755      if (const RecordType *RT = InstantiatedType->getAsRecordType())
756        D = RT->getDecl();
757    }
758
759  return D;
760}
761