SemaTemplateInstantiateDecl.cpp revision f97986dce99ea113744872de1d2a6d2da274061b 
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->setAccess(D->getAccess());
212  Owner->addDecl(SemaRef.Context, Enum);
213  Enum->startDefinition();
214
215  llvm::SmallVector<Sema::DeclPtrTy, 16> Enumerators;
216
217  EnumConstantDecl *LastEnumConst = 0;
218  for (EnumDecl::enumerator_iterator EC = D->enumerator_begin(SemaRef.Context),
219         ECEnd = D->enumerator_end(SemaRef.Context);
220       EC != ECEnd; ++EC) {
221    // The specified value for the enumerator.
222    OwningExprResult Value = SemaRef.Owned((Expr *)0);
223    if (Expr *UninstValue = EC->getInitExpr())
224      Value = SemaRef.InstantiateExpr(UninstValue, TemplateArgs);
225
226    // Drop the initial value and continue.
227    bool isInvalid = false;
228    if (Value.isInvalid()) {
229      Value = SemaRef.Owned((Expr *)0);
230      isInvalid = true;
231    }
232
233    EnumConstantDecl *EnumConst
234      = SemaRef.CheckEnumConstant(Enum, LastEnumConst,
235                                  EC->getLocation(), EC->getIdentifier(),
236                                  move(Value));
237
238    if (isInvalid) {
239      if (EnumConst)
240        EnumConst->setInvalidDecl();
241      Enum->setInvalidDecl();
242    }
243
244    if (EnumConst) {
245      Enum->addDecl(SemaRef.Context, EnumConst);
246      Enumerators.push_back(Sema::DeclPtrTy::make(EnumConst));
247      LastEnumConst = EnumConst;
248    }
249  }
250
251  // FIXME: Fixup LBraceLoc and RBraceLoc
252  SemaRef.ActOnEnumBody(Enum->getLocation(), SourceLocation(), SourceLocation(),
253                        Sema::DeclPtrTy::make(Enum),
254                        &Enumerators[0], Enumerators.size());
255
256  return Enum;
257}
258
259Decl *TemplateDeclInstantiator::VisitEnumConstantDecl(EnumConstantDecl *D) {
260  assert(false && "EnumConstantDecls can only occur within EnumDecls.");
261  return 0;
262}
263
264Decl *TemplateDeclInstantiator::VisitCXXRecordDecl(CXXRecordDecl *D) {
265  CXXRecordDecl *PrevDecl = 0;
266  if (D->isInjectedClassName())
267    PrevDecl = cast<CXXRecordDecl>(Owner);
268
269  CXXRecordDecl *Record
270    = CXXRecordDecl::Create(SemaRef.Context, D->getTagKind(), Owner,
271                            D->getLocation(), D->getIdentifier(), PrevDecl);
272  Record->setImplicit(D->isImplicit());
273  Record->setAccess(D->getAccess());
274  if (!D->isInjectedClassName())
275    Record->setInstantiationOfMemberClass(D);
276
277  Owner->addDecl(SemaRef.Context, Record);
278  return Record;
279}
280
281Decl *TemplateDeclInstantiator::VisitCXXMethodDecl(CXXMethodDecl *D) {
282  // Only handle actual methods; we'll deal with constructors,
283  // destructors, etc. separately.
284  if (D->getKind() != Decl::CXXMethod)
285    return 0;
286
287  Sema::LocalInstantiationScope Scope(SemaRef);
288
289  llvm::SmallVector<ParmVarDecl *, 16> Params;
290  QualType T = InstantiateFunctionType(D, Params);
291  if (T.isNull())
292    return 0;
293
294  // Build the instantiated method declaration.
295  CXXRecordDecl *Record = cast<CXXRecordDecl>(Owner);
296  CXXMethodDecl *Method
297    = CXXMethodDecl::Create(SemaRef.Context, Record, D->getLocation(),
298                            D->getDeclName(), T, D->isStatic(),
299                            D->isInline());
300  Method->setInstantiationOfMemberFunction(D);
301
302  // Attach the parameters
303  for (unsigned P = 0; P < Params.size(); ++P)
304    Params[P]->setOwningFunction(Method);
305  Method->setParams(SemaRef.Context, Params.data(), Params.size());
306
307  if (InitMethodInstantiation(Method, D))
308    Method->setInvalidDecl();
309
310  NamedDecl *PrevDecl
311    = SemaRef.LookupQualifiedName(Owner, Method->getDeclName(),
312                                  Sema::LookupOrdinaryName, true);
313  // In C++, the previous declaration we find might be a tag type
314  // (class or enum). In this case, the new declaration will hide the
315  // tag type. Note that this does does not apply if we're declaring a
316  // typedef (C++ [dcl.typedef]p4).
317  if (PrevDecl && PrevDecl->getIdentifierNamespace() == Decl::IDNS_Tag)
318    PrevDecl = 0;
319  bool Redeclaration = false;
320  bool OverloadableAttrRequired = false;
321  SemaRef.CheckFunctionDeclaration(Method, PrevDecl, Redeclaration,
322                                   /*FIXME:*/OverloadableAttrRequired);
323
324  if (!Method->isInvalidDecl() || !PrevDecl)
325    Owner->addDecl(SemaRef.Context, Method);
326  return Method;
327}
328
329Decl *TemplateDeclInstantiator::VisitCXXConstructorDecl(CXXConstructorDecl *D) {
330  Sema::LocalInstantiationScope Scope(SemaRef);
331
332  llvm::SmallVector<ParmVarDecl *, 16> Params;
333  QualType T = InstantiateFunctionType(D, Params);
334  if (T.isNull())
335    return 0;
336
337  // Build the instantiated method declaration.
338  CXXRecordDecl *Record = cast<CXXRecordDecl>(Owner);
339  QualType ClassTy = SemaRef.Context.getTypeDeclType(Record);
340  DeclarationName Name
341    = SemaRef.Context.DeclarationNames.getCXXConstructorName(
342                                 SemaRef.Context.getCanonicalType(ClassTy));
343  CXXConstructorDecl *Constructor
344    = CXXConstructorDecl::Create(SemaRef.Context, Record, D->getLocation(),
345                                 Name, T, D->isExplicit(), D->isInline(),
346                                 false);
347  Constructor->setInstantiationOfMemberFunction(D);
348
349  // Attach the parameters
350  for (unsigned P = 0; P < Params.size(); ++P)
351    Params[P]->setOwningFunction(Constructor);
352  Constructor->setParams(SemaRef.Context, Params.data(), Params.size());
353
354  if (InitMethodInstantiation(Constructor, D))
355    Constructor->setInvalidDecl();
356
357  NamedDecl *PrevDecl
358    = SemaRef.LookupQualifiedName(Owner, Name, Sema::LookupOrdinaryName, true);
359
360  // In C++, the previous declaration we find might be a tag type
361  // (class or enum). In this case, the new declaration will hide the
362  // tag type. Note that this does does not apply if we're declaring a
363  // typedef (C++ [dcl.typedef]p4).
364  if (PrevDecl && PrevDecl->getIdentifierNamespace() == Decl::IDNS_Tag)
365    PrevDecl = 0;
366  bool Redeclaration = false;
367  bool OverloadableAttrRequired = false;
368  SemaRef.CheckFunctionDeclaration(Constructor, PrevDecl, Redeclaration,
369                                   /*FIXME:*/OverloadableAttrRequired);
370
371  Record->addedConstructor(SemaRef.Context, Constructor);
372  Owner->addDecl(SemaRef.Context, Constructor);
373  return Constructor;
374}
375
376Decl *TemplateDeclInstantiator::VisitCXXDestructorDecl(CXXDestructorDecl *D) {
377  Sema::LocalInstantiationScope Scope(SemaRef);
378
379  llvm::SmallVector<ParmVarDecl *, 16> Params;
380  QualType T = InstantiateFunctionType(D, Params);
381  if (T.isNull())
382    return 0;
383  assert(Params.size() == 0 && "Destructor with parameters?");
384
385  // Build the instantiated destructor declaration.
386  CXXRecordDecl *Record = cast<CXXRecordDecl>(Owner);
387  QualType ClassTy =
388    SemaRef.Context.getCanonicalType(SemaRef.Context.getTypeDeclType(Record));
389  CXXDestructorDecl *Destructor
390    = CXXDestructorDecl::Create(SemaRef.Context, Record,
391                                D->getLocation(),
392             SemaRef.Context.DeclarationNames.getCXXDestructorName(ClassTy),
393                                T, D->isInline(), false);
394  Destructor->setInstantiationOfMemberFunction(D);
395  if (InitMethodInstantiation(Destructor, D))
396    Destructor->setInvalidDecl();
397
398  bool Redeclaration = false;
399  bool OverloadableAttrRequired = false;
400  NamedDecl *PrevDecl = 0;
401  SemaRef.CheckFunctionDeclaration(Destructor, PrevDecl, Redeclaration,
402                                   /*FIXME:*/OverloadableAttrRequired);
403  Owner->addDecl(SemaRef.Context, Destructor);
404  return Destructor;
405}
406
407Decl *TemplateDeclInstantiator::VisitCXXConversionDecl(CXXConversionDecl *D) {
408  Sema::LocalInstantiationScope Scope(SemaRef);
409
410  llvm::SmallVector<ParmVarDecl *, 16> Params;
411  QualType T = InstantiateFunctionType(D, Params);
412  if (T.isNull())
413    return 0;
414  assert(Params.size() == 0 && "Destructor with parameters?");
415
416  // Build the instantiated conversion declaration.
417  CXXRecordDecl *Record = cast<CXXRecordDecl>(Owner);
418  QualType ClassTy = SemaRef.Context.getTypeDeclType(Record);
419  QualType ConvTy
420    = SemaRef.Context.getCanonicalType(T->getAsFunctionType()->getResultType());
421  CXXConversionDecl *Conversion
422    = CXXConversionDecl::Create(SemaRef.Context, Record,
423                                D->getLocation(),
424         SemaRef.Context.DeclarationNames.getCXXConversionFunctionName(ConvTy),
425                                T, D->isInline(), D->isExplicit());
426  Conversion->setInstantiationOfMemberFunction(D);
427  if (InitMethodInstantiation(Conversion, D))
428    Conversion->setInvalidDecl();
429
430  bool Redeclaration = false;
431  bool OverloadableAttrRequired = false;
432  NamedDecl *PrevDecl = 0;
433  SemaRef.CheckFunctionDeclaration(Conversion, PrevDecl, Redeclaration,
434                                   /*FIXME:*/OverloadableAttrRequired);
435  Owner->addDecl(SemaRef.Context, Conversion);
436  return Conversion;
437}
438
439ParmVarDecl *TemplateDeclInstantiator::VisitParmVarDecl(ParmVarDecl *D) {
440  QualType OrigT = SemaRef.InstantiateType(D->getOriginalType(), TemplateArgs,
441                                           D->getLocation(), D->getDeclName());
442  if (OrigT.isNull())
443    return 0;
444
445  QualType T = SemaRef.adjustParameterType(OrigT);
446
447  if (D->getDefaultArg()) {
448    // FIXME: Leave a marker for "uninstantiated" default
449    // arguments. They only get instantiated on demand at the call
450    // site.
451    unsigned DiagID = SemaRef.Diags.getCustomDiagID(Diagnostic::Warning,
452        "sorry, dropping default argument during template instantiation");
453    SemaRef.Diag(D->getDefaultArg()->getSourceRange().getBegin(), DiagID)
454      << D->getDefaultArg()->getSourceRange();
455  }
456
457  // Allocate the parameter
458  ParmVarDecl *Param = 0;
459  if (T == OrigT)
460    Param = ParmVarDecl::Create(SemaRef.Context, Owner, D->getLocation(),
461                                D->getIdentifier(), T, D->getStorageClass(),
462                                0);
463  else
464    Param = OriginalParmVarDecl::Create(SemaRef.Context, Owner,
465                                        D->getLocation(), D->getIdentifier(),
466                                        T, OrigT, D->getStorageClass(), 0);
467
468  // Note: we don't try to instantiate function parameters until after
469  // we've instantiated the function's type. Therefore, we don't have
470  // to check for 'void' parameter types here.
471  SemaRef.CurrentInstantiationScope->InstantiatedLocal(D, Param);
472  return Param;
473}
474
475Decl *
476TemplateDeclInstantiator::VisitOriginalParmVarDecl(OriginalParmVarDecl *D) {
477  // Since parameter types can decay either before or after
478  // instantiation, we simply treat OriginalParmVarDecls as
479  // ParmVarDecls the same way, and create one or the other depending
480  // on what happens after template instantiation.
481  return VisitParmVarDecl(D);
482}
483
484Decl *Sema::InstantiateDecl(Decl *D, DeclContext *Owner,
485                            const TemplateArgumentList &TemplateArgs) {
486  TemplateDeclInstantiator Instantiator(*this, Owner, TemplateArgs);
487  return Instantiator.Visit(D);
488}
489
490/// \brief Instantiates the type of the given function, including
491/// instantiating all of the function parameters.
492///
493/// \param D The function that we will be instantiated
494///
495/// \param Params the instantiated parameter declarations
496
497/// \returns the instantiated function's type if successfull, a NULL
498/// type if there was an error.
499QualType
500TemplateDeclInstantiator::InstantiateFunctionType(FunctionDecl *D,
501                              llvm::SmallVectorImpl<ParmVarDecl *> &Params) {
502  bool InvalidDecl = false;
503
504  // Instantiate the function parameters
505  TemplateDeclInstantiator ParamInstantiator(SemaRef, 0, TemplateArgs);
506  llvm::SmallVector<QualType, 16> ParamTys;
507  for (FunctionDecl::param_iterator P = D->param_begin(),
508                                 PEnd = D->param_end();
509       P != PEnd; ++P) {
510    if (ParmVarDecl *PInst = ParamInstantiator.VisitParmVarDecl(*P)) {
511      if (PInst->getType()->isVoidType()) {
512        SemaRef.Diag(PInst->getLocation(), diag::err_param_with_void_type);
513        PInst->setInvalidDecl();
514      }
515      else if (SemaRef.RequireNonAbstractType(PInst->getLocation(),
516                                              PInst->getType(),
517                                              diag::err_abstract_type_in_decl,
518                                              Sema::AbstractParamType))
519        PInst->setInvalidDecl();
520
521      Params.push_back(PInst);
522      ParamTys.push_back(PInst->getType());
523
524      if (PInst->isInvalidDecl())
525        InvalidDecl = true;
526    } else
527      InvalidDecl = true;
528  }
529
530  // FIXME: Deallocate dead declarations.
531  if (InvalidDecl)
532    return QualType();
533
534  const FunctionProtoType *Proto = D->getType()->getAsFunctionProtoType();
535  assert(Proto && "Missing prototype?");
536  QualType ResultType
537    = SemaRef.InstantiateType(Proto->getResultType(), TemplateArgs,
538                              D->getLocation(), D->getDeclName());
539  if (ResultType.isNull())
540    return QualType();
541
542  return SemaRef.BuildFunctionType(ResultType, ParamTys.data(), ParamTys.size(),
543                                   Proto->isVariadic(), Proto->getTypeQuals(),
544                                   D->getLocation(), D->getDeclName());
545}
546
547/// \brief Initializes common fields of an instantiated method
548/// declaration (New) from the corresponding fields of its template
549/// (Tmpl).
550///
551/// \returns true if there was an error
552bool
553TemplateDeclInstantiator::InitMethodInstantiation(CXXMethodDecl *New,
554                                                  CXXMethodDecl *Tmpl) {
555  CXXRecordDecl *Record = cast<CXXRecordDecl>(Owner);
556  New->setAccess(Tmpl->getAccess());
557  if (Tmpl->isVirtualAsWritten()) {
558    New->setVirtualAsWritten(true);
559    Record->setAggregate(false);
560    Record->setPOD(false);
561    Record->setPolymorphic(true);
562  }
563  if (Tmpl->isDeleted())
564    New->setDeleted();
565  if (Tmpl->isPure()) {
566    New->setPure();
567    Record->setAbstract(true);
568  }
569
570  // FIXME: attributes
571  // FIXME: New needs a pointer to Tmpl
572  return false;
573}
574
575/// \brief Instantiate the definition of the given function from its
576/// template.
577///
578/// \param Function the already-instantiated declaration of a
579/// function.
580void Sema::InstantiateFunctionDefinition(SourceLocation PointOfInstantiation,
581                                         FunctionDecl *Function) {
582  // FIXME: make this work for function template specializations, too.
583
584  if (Function->isInvalidDecl())
585    return;
586
587  // Find the function body that we'll be substituting.
588  const FunctionDecl *PatternDecl
589    = Function->getInstantiatedFromMemberFunction();
590  Stmt *Pattern = 0;
591  if (PatternDecl)
592    Pattern = PatternDecl->getBody(Context, PatternDecl);
593
594  if (!Pattern)
595    return;
596
597  InstantiatingTemplate Inst(*this, PointOfInstantiation, Function);
598  if (Inst)
599    return;
600
601  ActOnStartOfFunctionDef(0, DeclPtrTy::make(Function));
602
603  // Introduce a new scope where local variable instantiations will be
604  // recorded.
605  LocalInstantiationScope Scope(*this);
606
607  // Introduce the instantiated function parameters into the local
608  // instantiation scope.
609  for (unsigned I = 0, N = PatternDecl->getNumParams(); I != N; ++I)
610    Scope.InstantiatedLocal(PatternDecl->getParamDecl(I),
611                            Function->getParamDecl(I));
612
613  // Enter the scope of this instantiation. We don't use
614  // PushDeclContext because we don't have a scope.
615  DeclContext *PreviousContext = CurContext;
616  CurContext = Function;
617
618  // Instantiate the function body.
619  OwningStmtResult Body
620    = InstantiateStmt(Pattern, getTemplateInstantiationArgs(Function));
621
622  ActOnFinishFunctionBody(DeclPtrTy::make(Function), move(Body),
623                          /*IsInstantiation=*/true);
624
625  CurContext = PreviousContext;
626
627  DeclGroupRef DG(Function);
628  Consumer.HandleTopLevelDecl(DG);
629}
630
631/// \brief Instantiate the definition of the given variable from its
632/// template.
633///
634/// \param Var the already-instantiated declaration of a variable.
635void Sema::InstantiateVariableDefinition(VarDecl *Var) {
636  // FIXME: Implement this!
637}
638
639static bool isInstantiationOf(ASTContext &Ctx, NamedDecl *D, Decl *Other) {
640  if (D->getKind() != Other->getKind())
641    return false;
642
643  if (CXXRecordDecl *Record = dyn_cast<CXXRecordDecl>(Other))
644    return Ctx.getCanonicalDecl(Record->getInstantiatedFromMemberClass())
645             == Ctx.getCanonicalDecl(D);
646
647  if (FunctionDecl *Function = dyn_cast<FunctionDecl>(Other))
648    return Ctx.getCanonicalDecl(Function->getInstantiatedFromMemberFunction())
649             == Ctx.getCanonicalDecl(D);
650
651  // FIXME: Need something similar to the above for EnumDecls.
652
653  // FIXME: How can we find instantiations of anonymous unions?
654
655  return D->getDeclName() && isa<NamedDecl>(Other) &&
656    D->getDeclName() == cast<NamedDecl>(Other)->getDeclName();
657}
658
659template<typename ForwardIterator>
660static NamedDecl *findInstantiationOf(ASTContext &Ctx,
661                                      NamedDecl *D,
662                                      ForwardIterator first,
663                                      ForwardIterator last) {
664  for (; first != last; ++first)
665    if (isInstantiationOf(Ctx, D, *first))
666      return cast<NamedDecl>(*first);
667
668  return 0;
669}
670
671/// \brief Find the instantiation of the given declaration with the
672/// given template arguments.
673///
674/// This routine is intended to be used when \p D is a declaration
675/// referenced from within a template, that needs to mapped into the
676/// corresponding declaration within an instantiation. For example,
677/// given:
678///
679/// \code
680/// template<typename T>
681/// struct X {
682///   enum Kind {
683///     KnownValue = sizeof(T)
684///   };
685///
686///   bool getKind() const { return KnownValue; }
687/// };
688///
689/// template struct X<int>;
690/// \endcode
691///
692/// In the instantiation of X<int>::getKind(), we need to map the
693/// EnumConstantDecl for KnownValue (which refers to
694/// X<T>::<Kind>::KnownValue) to its instantiation
695/// (X<int>::<Kind>::KnownValue). InstantiateDeclRef() performs this
696/// mapping, given the template arguments 'int'.
697NamedDecl *
698Sema::InstantiateDeclRef(NamedDecl *D, const TemplateArgumentList &TemplateArgs) {
699  DeclContext *ParentDC = D->getDeclContext();
700
701  if (!ParentDC->isFileContext()) {
702    NamedDecl *ParentDecl = cast<NamedDecl>(ParentDC);
703    ParentDecl = InstantiateDeclRef(ParentDecl, TemplateArgs);
704    if (!ParentDecl)
705      return 0;
706
707    ParentDC = cast<DeclContext>(ParentDecl);
708  }
709
710  if (ParentDC->isFunctionOrMethod()) {
711    // D is a local of some kind. Look into the map of local
712    // variables to their instantiations.
713    return cast<NamedDecl>(CurrentInstantiationScope->getInstantiationOf(D));
714  }
715
716  if (ParentDC != D->getDeclContext()) {
717    // We performed some kind of instantiation in the parent context,
718    // so now we need to look into the instantiated parent context to
719    // find the instantiation of the declaration D.
720    NamedDecl *Result = 0;
721    if (D->getDeclName()) {
722      DeclContext::lookup_result Found
723        = ParentDC->lookup(Context, D->getDeclName());
724      Result = findInstantiationOf(Context, D, Found.first, Found.second);
725    } else {
726      // Since we don't have a name for the entity we're looking for,
727      // our only option is to walk through all of the declarations to
728      // find that name. This will occur in a few cases:
729      //
730      //   - anonymous struct/union within a template
731      //   - unnamed class/struct/union/enum within a template
732      //
733      // FIXME: Find a better way to find these instantiations!
734      Result = findInstantiationOf(Context, D,
735                                   ParentDC->decls_begin(Context),
736                                   ParentDC->decls_end(Context));
737    }
738    assert(Result && "Unable to find instantiation of declaration!");
739    D = Result;
740  }
741
742  // D itself might be a class template that we need to instantiate
743  // with the given template arguments.
744  if (CXXRecordDecl *Record = dyn_cast<CXXRecordDecl>(D))
745    if (ClassTemplateDecl *ClassTemplate = Record->getDescribedClassTemplate()) {
746      QualType InjectedClassName
747        = ClassTemplate->getInjectedClassNameType(Context);
748      QualType InstantiatedType = InstantiateType(InjectedClassName,
749                                                  TemplateArgs,
750                                                  Record->getLocation(),
751                                                  Record->getDeclName());
752      if (InstantiatedType.isNull())
753        return 0;
754      if (const RecordType *RT = InstantiatedType->getAsRecordType())
755        D = RT->getDecl();
756    }
757
758  return D;
759}
760