SemaTemplateInstantiateDecl.cpp revision 1637be727f2a0434c1ed7aa385ea1c18328b0ccd 
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 *VisitFunctionDecl(FunctionDecl *D);
48    Decl *VisitCXXRecordDecl(CXXRecordDecl *D);
49    Decl *VisitCXXMethodDecl(CXXMethodDecl *D);
50    Decl *VisitCXXConstructorDecl(CXXConstructorDecl *D);
51    Decl *VisitCXXDestructorDecl(CXXDestructorDecl *D);
52    Decl *VisitCXXConversionDecl(CXXConversionDecl *D);
53    ParmVarDecl *VisitParmVarDecl(ParmVarDecl *D);
54    Decl *VisitOriginalParmVarDecl(OriginalParmVarDecl *D);
55
56    // Base case. FIXME: Remove once we can instantiate everything.
57    Decl *VisitDecl(Decl *) {
58      assert(false && "Template instantiation of unknown declaration kind!");
59      return 0;
60    }
61
62    // Helper functions for instantiating methods.
63    QualType InstantiateFunctionType(FunctionDecl *D,
64                             llvm::SmallVectorImpl<ParmVarDecl *> &Params);
65    bool InitFunctionInstantiation(FunctionDecl *New, FunctionDecl *Tmpl);
66    bool InitMethodInstantiation(CXXMethodDecl *New, CXXMethodDecl *Tmpl);
67  };
68}
69
70Decl *
71TemplateDeclInstantiator::VisitTranslationUnitDecl(TranslationUnitDecl *D) {
72  assert(false && "Translation units cannot be instantiated");
73  return D;
74}
75
76Decl *
77TemplateDeclInstantiator::VisitNamespaceDecl(NamespaceDecl *D) {
78  assert(false && "Namespaces cannot be instantiated");
79  return D;
80}
81
82Decl *TemplateDeclInstantiator::VisitTypedefDecl(TypedefDecl *D) {
83  bool Invalid = false;
84  QualType T = D->getUnderlyingType();
85  if (T->isDependentType()) {
86    T = SemaRef.InstantiateType(T, TemplateArgs,
87                                D->getLocation(), D->getDeclName());
88    if (T.isNull()) {
89      Invalid = true;
90      T = SemaRef.Context.IntTy;
91    }
92  }
93
94  // Create the new typedef
95  TypedefDecl *Typedef
96    = TypedefDecl::Create(SemaRef.Context, Owner, D->getLocation(),
97                          D->getIdentifier(), T);
98  if (Invalid)
99    Typedef->setInvalidDecl();
100
101  Owner->addDecl(SemaRef.Context, Typedef);
102
103  return Typedef;
104}
105
106Decl *TemplateDeclInstantiator::VisitVarDecl(VarDecl *D) {
107  // Instantiate the type of the declaration
108  QualType T = SemaRef.InstantiateType(D->getType(), TemplateArgs,
109                                       D->getTypeSpecStartLoc(),
110                                       D->getDeclName());
111  if (T.isNull())
112    return 0;
113
114  // Build the instantiated declaration
115  VarDecl *Var = VarDecl::Create(SemaRef.Context, Owner,
116                                 D->getLocation(), D->getIdentifier(),
117                                 T, D->getStorageClass(),
118                                 D->getTypeSpecStartLoc());
119  Var->setThreadSpecified(D->isThreadSpecified());
120  Var->setCXXDirectInitializer(D->hasCXXDirectInitializer());
121  Var->setDeclaredInCondition(D->isDeclaredInCondition());
122
123  // FIXME: In theory, we could have a previous declaration for variables that
124  // are not static data members.
125  bool Redeclaration = false;
126  SemaRef.CheckVariableDeclaration(Var, 0, Redeclaration);
127  Owner->addDecl(SemaRef.Context, Var);
128
129  if (D->getInit()) {
130    OwningExprResult Init
131      = SemaRef.InstantiateExpr(D->getInit(), TemplateArgs);
132    if (Init.isInvalid())
133      Var->setInvalidDecl();
134    else
135      SemaRef.AddInitializerToDecl(Sema::DeclPtrTy::make(Var), move(Init),
136                                   D->hasCXXDirectInitializer());
137  } else {
138    // FIXME: Call ActOnUninitializedDecl? (Not always)
139  }
140
141  return Var;
142}
143
144Decl *TemplateDeclInstantiator::VisitFieldDecl(FieldDecl *D) {
145  bool Invalid = false;
146  QualType T = D->getType();
147  if (T->isDependentType())  {
148    T = SemaRef.InstantiateType(T, TemplateArgs,
149                                D->getLocation(), D->getDeclName());
150    if (!T.isNull() && T->isFunctionType()) {
151      // C++ [temp.arg.type]p3:
152      //   If a declaration acquires a function type through a type
153      //   dependent on a template-parameter and this causes a
154      //   declaration that does not use the syntactic form of a
155      //   function declarator to have function type, the program is
156      //   ill-formed.
157      SemaRef.Diag(D->getLocation(), diag::err_field_instantiates_to_function)
158        << T;
159      T = QualType();
160      Invalid = true;
161    }
162  }
163
164  Expr *BitWidth = D->getBitWidth();
165  if (Invalid)
166    BitWidth = 0;
167  else if (BitWidth) {
168    // The bit-width expression is not potentially evaluated.
169    EnterExpressionEvaluationContext Unevaluated(SemaRef, Action::Unevaluated);
170
171    OwningExprResult InstantiatedBitWidth
172      = SemaRef.InstantiateExpr(BitWidth, TemplateArgs);
173    if (InstantiatedBitWidth.isInvalid()) {
174      Invalid = true;
175      BitWidth = 0;
176    } else
177      BitWidth = InstantiatedBitWidth.takeAs<Expr>();
178  }
179
180  FieldDecl *Field = SemaRef.CheckFieldDecl(D->getDeclName(), T,
181                                            cast<RecordDecl>(Owner),
182                                            D->getLocation(),
183                                            D->isMutable(),
184                                            BitWidth,
185                                            D->getAccess(),
186                                            0);
187  if (Field) {
188    if (Invalid)
189      Field->setInvalidDecl();
190
191    Owner->addDecl(SemaRef.Context, Field);
192  }
193
194  return Field;
195}
196
197Decl *TemplateDeclInstantiator::VisitStaticAssertDecl(StaticAssertDecl *D) {
198  Expr *AssertExpr = D->getAssertExpr();
199
200  // The expression in a static assertion is not potentially evaluated.
201  EnterExpressionEvaluationContext Unevaluated(SemaRef, Action::Unevaluated);
202
203  OwningExprResult InstantiatedAssertExpr
204    = SemaRef.InstantiateExpr(AssertExpr, TemplateArgs);
205  if (InstantiatedAssertExpr.isInvalid())
206    return 0;
207
208  OwningExprResult Message = SemaRef.Clone(D->getMessage());
209  Decl *StaticAssert
210    = SemaRef.ActOnStaticAssertDeclaration(D->getLocation(),
211                                           move(InstantiatedAssertExpr),
212                                           move(Message)).getAs<Decl>();
213  return StaticAssert;
214}
215
216Decl *TemplateDeclInstantiator::VisitEnumDecl(EnumDecl *D) {
217  EnumDecl *Enum = EnumDecl::Create(SemaRef.Context, Owner,
218                                    D->getLocation(), D->getIdentifier(),
219                                    /*PrevDecl=*/0);
220  Enum->setInstantiationOfMemberEnum(D);
221  Enum->setAccess(D->getAccess());
222  Owner->addDecl(SemaRef.Context, Enum);
223  Enum->startDefinition();
224
225  llvm::SmallVector<Sema::DeclPtrTy, 4> Enumerators;
226
227  EnumConstantDecl *LastEnumConst = 0;
228  for (EnumDecl::enumerator_iterator EC = D->enumerator_begin(SemaRef.Context),
229         ECEnd = D->enumerator_end(SemaRef.Context);
230       EC != ECEnd; ++EC) {
231    // The specified value for the enumerator.
232    OwningExprResult Value = SemaRef.Owned((Expr *)0);
233    if (Expr *UninstValue = EC->getInitExpr()) {
234      // The enumerator's value expression is not potentially evaluated.
235      EnterExpressionEvaluationContext Unevaluated(SemaRef,
236                                                   Action::Unevaluated);
237
238      Value = SemaRef.InstantiateExpr(UninstValue, TemplateArgs);
239    }
240
241    // Drop the initial value and continue.
242    bool isInvalid = false;
243    if (Value.isInvalid()) {
244      Value = SemaRef.Owned((Expr *)0);
245      isInvalid = true;
246    }
247
248    EnumConstantDecl *EnumConst
249      = SemaRef.CheckEnumConstant(Enum, LastEnumConst,
250                                  EC->getLocation(), EC->getIdentifier(),
251                                  move(Value));
252
253    if (isInvalid) {
254      if (EnumConst)
255        EnumConst->setInvalidDecl();
256      Enum->setInvalidDecl();
257    }
258
259    if (EnumConst) {
260      Enum->addDecl(SemaRef.Context, EnumConst);
261      Enumerators.push_back(Sema::DeclPtrTy::make(EnumConst));
262      LastEnumConst = EnumConst;
263    }
264  }
265
266  // FIXME: Fixup LBraceLoc and RBraceLoc
267  SemaRef.ActOnEnumBody(Enum->getLocation(), SourceLocation(), SourceLocation(),
268                        Sema::DeclPtrTy::make(Enum),
269                        &Enumerators[0], Enumerators.size());
270
271  return Enum;
272}
273
274Decl *TemplateDeclInstantiator::VisitEnumConstantDecl(EnumConstantDecl *D) {
275  assert(false && "EnumConstantDecls can only occur within EnumDecls.");
276  return 0;
277}
278
279Decl *TemplateDeclInstantiator::VisitCXXRecordDecl(CXXRecordDecl *D) {
280  CXXRecordDecl *PrevDecl = 0;
281  if (D->isInjectedClassName())
282    PrevDecl = cast<CXXRecordDecl>(Owner);
283
284  CXXRecordDecl *Record
285    = CXXRecordDecl::Create(SemaRef.Context, D->getTagKind(), Owner,
286                            D->getLocation(), D->getIdentifier(), PrevDecl);
287  Record->setImplicit(D->isImplicit());
288  Record->setAccess(D->getAccess());
289  if (!D->isInjectedClassName())
290    Record->setInstantiationOfMemberClass(D);
291
292  Owner->addDecl(SemaRef.Context, Record);
293  return Record;
294}
295
296Decl *TemplateDeclInstantiator::VisitFunctionDecl(FunctionDecl *D) {
297  // FIXME: Look for existing specializations (explicit or otherwise).
298
299  Sema::LocalInstantiationScope Scope(SemaRef);
300
301  llvm::SmallVector<ParmVarDecl *, 4> Params;
302  QualType T = InstantiateFunctionType(D, Params);
303  if (T.isNull())
304    return 0;
305
306  // Build the instantiated method declaration.
307  FunctionDecl *Function
308    = FunctionDecl::Create(SemaRef.Context, Owner, D->getLocation(),
309                           D->getDeclName(), T, D->getStorageClass(),
310                           D->isInline(), D->hasWrittenPrototype(),
311                           D->getTypeSpecStartLoc());
312
313  // FIXME: friend functions
314
315  // Attach the parameters
316  for (unsigned P = 0; P < Params.size(); ++P)
317    Params[P]->setOwningFunction(Function);
318  Function->setParams(SemaRef.Context, Params.data(), Params.size());
319
320  if (InitFunctionInstantiation(Function, D))
321    Function->setInvalidDecl();
322
323  bool Redeclaration = false;
324  bool OverloadableAttrRequired = false;
325  NamedDecl *PrevDecl = 0;
326  SemaRef.CheckFunctionDeclaration(Function, PrevDecl, Redeclaration,
327                                   /*FIXME:*/OverloadableAttrRequired);
328
329
330  // FIXME: link this to the function template from which it was instantiated.
331
332  return Function;
333}
334
335Decl *TemplateDeclInstantiator::VisitCXXMethodDecl(CXXMethodDecl *D) {
336  // FIXME: Look for existing, explicit specializations.
337  Sema::LocalInstantiationScope Scope(SemaRef);
338
339  llvm::SmallVector<ParmVarDecl *, 4> Params;
340  QualType T = InstantiateFunctionType(D, Params);
341  if (T.isNull())
342    return 0;
343
344  // Build the instantiated method declaration.
345  CXXRecordDecl *Record = cast<CXXRecordDecl>(Owner);
346  CXXMethodDecl *Method
347    = CXXMethodDecl::Create(SemaRef.Context, Record, D->getLocation(),
348                            D->getDeclName(), T, D->isStatic(),
349                            D->isInline());
350  Method->setInstantiationOfMemberFunction(D);
351
352  // Attach the parameters
353  for (unsigned P = 0; P < Params.size(); ++P)
354    Params[P]->setOwningFunction(Method);
355  Method->setParams(SemaRef.Context, Params.data(), Params.size());
356
357  if (InitMethodInstantiation(Method, D))
358    Method->setInvalidDecl();
359
360  NamedDecl *PrevDecl
361    = SemaRef.LookupQualifiedName(Owner, Method->getDeclName(),
362                                  Sema::LookupOrdinaryName, true);
363  // In C++, the previous declaration we find might be a tag type
364  // (class or enum). In this case, the new declaration will hide the
365  // tag type. Note that this does does not apply if we're declaring a
366  // typedef (C++ [dcl.typedef]p4).
367  if (PrevDecl && PrevDecl->getIdentifierNamespace() == Decl::IDNS_Tag)
368    PrevDecl = 0;
369  bool Redeclaration = false;
370  bool OverloadableAttrRequired = false;
371  SemaRef.CheckFunctionDeclaration(Method, PrevDecl, Redeclaration,
372                                   /*FIXME:*/OverloadableAttrRequired);
373
374  if (!Method->isInvalidDecl() || !PrevDecl)
375    Owner->addDecl(SemaRef.Context, Method);
376  return Method;
377}
378
379Decl *TemplateDeclInstantiator::VisitCXXConstructorDecl(CXXConstructorDecl *D) {
380  // FIXME: Look for existing, explicit specializations.
381  Sema::LocalInstantiationScope Scope(SemaRef);
382
383  llvm::SmallVector<ParmVarDecl *, 4> Params;
384  QualType T = InstantiateFunctionType(D, Params);
385  if (T.isNull())
386    return 0;
387
388  // Build the instantiated method declaration.
389  CXXRecordDecl *Record = cast<CXXRecordDecl>(Owner);
390  QualType ClassTy = SemaRef.Context.getTypeDeclType(Record);
391  DeclarationName Name
392    = SemaRef.Context.DeclarationNames.getCXXConstructorName(
393                                 SemaRef.Context.getCanonicalType(ClassTy));
394  CXXConstructorDecl *Constructor
395    = CXXConstructorDecl::Create(SemaRef.Context, Record, D->getLocation(),
396                                 Name, T, D->isExplicit(), D->isInline(),
397                                 false);
398  Constructor->setInstantiationOfMemberFunction(D);
399
400  // Attach the parameters
401  for (unsigned P = 0; P < Params.size(); ++P)
402    Params[P]->setOwningFunction(Constructor);
403  Constructor->setParams(SemaRef.Context, Params.data(), Params.size());
404
405  if (InitMethodInstantiation(Constructor, D))
406    Constructor->setInvalidDecl();
407
408  NamedDecl *PrevDecl
409    = SemaRef.LookupQualifiedName(Owner, Name, Sema::LookupOrdinaryName, true);
410
411  // In C++, the previous declaration we find might be a tag type
412  // (class or enum). In this case, the new declaration will hide the
413  // tag type. Note that this does does not apply if we're declaring a
414  // typedef (C++ [dcl.typedef]p4).
415  if (PrevDecl && PrevDecl->getIdentifierNamespace() == Decl::IDNS_Tag)
416    PrevDecl = 0;
417  bool Redeclaration = false;
418  bool OverloadableAttrRequired = false;
419  SemaRef.CheckFunctionDeclaration(Constructor, PrevDecl, Redeclaration,
420                                   /*FIXME:*/OverloadableAttrRequired);
421
422  Record->addedConstructor(SemaRef.Context, Constructor);
423  Owner->addDecl(SemaRef.Context, Constructor);
424  return Constructor;
425}
426
427Decl *TemplateDeclInstantiator::VisitCXXDestructorDecl(CXXDestructorDecl *D) {
428  // FIXME: Look for existing, explicit specializations.
429  Sema::LocalInstantiationScope Scope(SemaRef);
430
431  llvm::SmallVector<ParmVarDecl *, 4> Params;
432  QualType T = InstantiateFunctionType(D, Params);
433  if (T.isNull())
434    return 0;
435  assert(Params.size() == 0 && "Destructor with parameters?");
436
437  // Build the instantiated destructor declaration.
438  CXXRecordDecl *Record = cast<CXXRecordDecl>(Owner);
439  QualType ClassTy =
440    SemaRef.Context.getCanonicalType(SemaRef.Context.getTypeDeclType(Record));
441  CXXDestructorDecl *Destructor
442    = CXXDestructorDecl::Create(SemaRef.Context, Record,
443                                D->getLocation(),
444             SemaRef.Context.DeclarationNames.getCXXDestructorName(ClassTy),
445                                T, D->isInline(), false);
446  Destructor->setInstantiationOfMemberFunction(D);
447  if (InitMethodInstantiation(Destructor, D))
448    Destructor->setInvalidDecl();
449
450  bool Redeclaration = false;
451  bool OverloadableAttrRequired = false;
452  NamedDecl *PrevDecl = 0;
453  SemaRef.CheckFunctionDeclaration(Destructor, PrevDecl, Redeclaration,
454                                   /*FIXME:*/OverloadableAttrRequired);
455  Owner->addDecl(SemaRef.Context, Destructor);
456  return Destructor;
457}
458
459Decl *TemplateDeclInstantiator::VisitCXXConversionDecl(CXXConversionDecl *D) {
460  // FIXME: Look for existing, explicit specializations.
461  Sema::LocalInstantiationScope Scope(SemaRef);
462
463  llvm::SmallVector<ParmVarDecl *, 4> Params;
464  QualType T = InstantiateFunctionType(D, Params);
465  if (T.isNull())
466    return 0;
467  assert(Params.size() == 0 && "Destructor with parameters?");
468
469  // Build the instantiated conversion declaration.
470  CXXRecordDecl *Record = cast<CXXRecordDecl>(Owner);
471  QualType ClassTy = SemaRef.Context.getTypeDeclType(Record);
472  QualType ConvTy
473    = SemaRef.Context.getCanonicalType(T->getAsFunctionType()->getResultType());
474  CXXConversionDecl *Conversion
475    = CXXConversionDecl::Create(SemaRef.Context, Record,
476                                D->getLocation(),
477         SemaRef.Context.DeclarationNames.getCXXConversionFunctionName(ConvTy),
478                                T, D->isInline(), D->isExplicit());
479  Conversion->setInstantiationOfMemberFunction(D);
480  if (InitMethodInstantiation(Conversion, D))
481    Conversion->setInvalidDecl();
482
483  bool Redeclaration = false;
484  bool OverloadableAttrRequired = false;
485  NamedDecl *PrevDecl = 0;
486  SemaRef.CheckFunctionDeclaration(Conversion, PrevDecl, Redeclaration,
487                                   /*FIXME:*/OverloadableAttrRequired);
488  Owner->addDecl(SemaRef.Context, Conversion);
489  return Conversion;
490}
491
492ParmVarDecl *TemplateDeclInstantiator::VisitParmVarDecl(ParmVarDecl *D) {
493  QualType OrigT = SemaRef.InstantiateType(D->getOriginalType(), TemplateArgs,
494                                           D->getLocation(), D->getDeclName());
495  if (OrigT.isNull())
496    return 0;
497
498  QualType T = SemaRef.adjustParameterType(OrigT);
499
500  if (D->getDefaultArg()) {
501    // FIXME: Leave a marker for "uninstantiated" default
502    // arguments. They only get instantiated on demand at the call
503    // site.
504    unsigned DiagID = SemaRef.Diags.getCustomDiagID(Diagnostic::Warning,
505        "sorry, dropping default argument during template instantiation");
506    SemaRef.Diag(D->getDefaultArg()->getSourceRange().getBegin(), DiagID)
507      << D->getDefaultArg()->getSourceRange();
508  }
509
510  // Allocate the parameter
511  ParmVarDecl *Param = 0;
512  if (T == OrigT)
513    Param = ParmVarDecl::Create(SemaRef.Context, Owner, D->getLocation(),
514                                D->getIdentifier(), T, D->getStorageClass(),
515                                0);
516  else
517    Param = OriginalParmVarDecl::Create(SemaRef.Context, Owner,
518                                        D->getLocation(), D->getIdentifier(),
519                                        T, OrigT, D->getStorageClass(), 0);
520
521  // Note: we don't try to instantiate function parameters until after
522  // we've instantiated the function's type. Therefore, we don't have
523  // to check for 'void' parameter types here.
524  SemaRef.CurrentInstantiationScope->InstantiatedLocal(D, Param);
525  return Param;
526}
527
528Decl *
529TemplateDeclInstantiator::VisitOriginalParmVarDecl(OriginalParmVarDecl *D) {
530  // Since parameter types can decay either before or after
531  // instantiation, we simply treat OriginalParmVarDecls as
532  // ParmVarDecls the same way, and create one or the other depending
533  // on what happens after template instantiation.
534  return VisitParmVarDecl(D);
535}
536
537Decl *Sema::InstantiateDecl(Decl *D, DeclContext *Owner,
538                            const TemplateArgumentList &TemplateArgs) {
539  TemplateDeclInstantiator Instantiator(*this, Owner, TemplateArgs);
540  return Instantiator.Visit(D);
541}
542
543/// \brief Instantiates the type of the given function, including
544/// instantiating all of the function parameters.
545///
546/// \param D The function that we will be instantiated
547///
548/// \param Params the instantiated parameter declarations
549
550/// \returns the instantiated function's type if successfull, a NULL
551/// type if there was an error.
552QualType
553TemplateDeclInstantiator::InstantiateFunctionType(FunctionDecl *D,
554                              llvm::SmallVectorImpl<ParmVarDecl *> &Params) {
555  bool InvalidDecl = false;
556
557  // Instantiate the function parameters
558  TemplateDeclInstantiator ParamInstantiator(SemaRef, 0, TemplateArgs);
559  llvm::SmallVector<QualType, 4> ParamTys;
560  for (FunctionDecl::param_iterator P = D->param_begin(),
561                                 PEnd = D->param_end();
562       P != PEnd; ++P) {
563    if (ParmVarDecl *PInst = ParamInstantiator.VisitParmVarDecl(*P)) {
564      if (PInst->getType()->isVoidType()) {
565        SemaRef.Diag(PInst->getLocation(), diag::err_param_with_void_type);
566        PInst->setInvalidDecl();
567      }
568      else if (SemaRef.RequireNonAbstractType(PInst->getLocation(),
569                                              PInst->getType(),
570                                              diag::err_abstract_type_in_decl,
571                                              Sema::AbstractParamType))
572        PInst->setInvalidDecl();
573
574      Params.push_back(PInst);
575      ParamTys.push_back(PInst->getType());
576
577      if (PInst->isInvalidDecl())
578        InvalidDecl = true;
579    } else
580      InvalidDecl = true;
581  }
582
583  // FIXME: Deallocate dead declarations.
584  if (InvalidDecl)
585    return QualType();
586
587  const FunctionProtoType *Proto = D->getType()->getAsFunctionProtoType();
588  assert(Proto && "Missing prototype?");
589  QualType ResultType
590    = SemaRef.InstantiateType(Proto->getResultType(), TemplateArgs,
591                              D->getLocation(), D->getDeclName());
592  if (ResultType.isNull())
593    return QualType();
594
595  return SemaRef.BuildFunctionType(ResultType, ParamTys.data(), ParamTys.size(),
596                                   Proto->isVariadic(), Proto->getTypeQuals(),
597                                   D->getLocation(), D->getDeclName());
598}
599
600/// \brief Initializes the common fields of an instantiation function
601/// declaration (New) from the corresponding fields of its template (Tmpl).
602///
603/// \returns true if there was an error
604bool
605TemplateDeclInstantiator::InitFunctionInstantiation(FunctionDecl *New,
606                                                    FunctionDecl *Tmpl) {
607  if (Tmpl->isDeleted())
608    New->setDeleted();
609  return false;
610}
611
612/// \brief Initializes common fields of an instantiated method
613/// declaration (New) from the corresponding fields of its template
614/// (Tmpl).
615///
616/// \returns true if there was an error
617bool
618TemplateDeclInstantiator::InitMethodInstantiation(CXXMethodDecl *New,
619                                                  CXXMethodDecl *Tmpl) {
620  if (InitFunctionInstantiation(New, Tmpl))
621    return true;
622
623  CXXRecordDecl *Record = cast<CXXRecordDecl>(Owner);
624  New->setAccess(Tmpl->getAccess());
625  if (Tmpl->isVirtualAsWritten()) {
626    New->setVirtualAsWritten(true);
627    Record->setAggregate(false);
628    Record->setPOD(false);
629    Record->setPolymorphic(true);
630  }
631  if (Tmpl->isPure()) {
632    New->setPure();
633    Record->setAbstract(true);
634  }
635
636  // FIXME: attributes
637  // FIXME: New needs a pointer to Tmpl
638  return false;
639}
640
641/// \brief Instantiate the definition of the given function from its
642/// template.
643///
644/// \param Function the already-instantiated declaration of a
645/// function.
646void Sema::InstantiateFunctionDefinition(SourceLocation PointOfInstantiation,
647                                         FunctionDecl *Function) {
648  if (Function->isInvalidDecl())
649    return;
650
651  assert(!Function->getBody(Context) && "Already instantiated!");
652
653  // Find the function body that we'll be substituting.
654  const FunctionDecl *PatternDecl = 0;
655  if (FunctionTemplateDecl *Primary = Function->getPrimaryTemplate())
656    PatternDecl = Primary->getTemplatedDecl();
657  else
658    PatternDecl = Function->getInstantiatedFromMemberFunction();
659  Stmt *Pattern = 0;
660  if (PatternDecl)
661    Pattern = PatternDecl->getBody(Context, PatternDecl);
662
663  if (!Pattern)
664    return;
665
666  InstantiatingTemplate Inst(*this, PointOfInstantiation, Function);
667  if (Inst)
668    return;
669
670  ActOnStartOfFunctionDef(0, DeclPtrTy::make(Function));
671
672  // Introduce a new scope where local variable instantiations will be
673  // recorded.
674  LocalInstantiationScope Scope(*this);
675
676  // Introduce the instantiated function parameters into the local
677  // instantiation scope.
678  for (unsigned I = 0, N = PatternDecl->getNumParams(); I != N; ++I)
679    Scope.InstantiatedLocal(PatternDecl->getParamDecl(I),
680                            Function->getParamDecl(I));
681
682  // Enter the scope of this instantiation. We don't use
683  // PushDeclContext because we don't have a scope.
684  DeclContext *PreviousContext = CurContext;
685  CurContext = Function;
686
687  // Instantiate the function body.
688  OwningStmtResult Body
689    = InstantiateStmt(Pattern, getTemplateInstantiationArgs(Function));
690
691  ActOnFinishFunctionBody(DeclPtrTy::make(Function), move(Body),
692                          /*IsInstantiation=*/true);
693
694  CurContext = PreviousContext;
695
696  DeclGroupRef DG(Function);
697  Consumer.HandleTopLevelDecl(DG);
698}
699
700/// \brief Instantiate the definition of the given variable from its
701/// template.
702///
703/// \param Var the already-instantiated declaration of a variable.
704void Sema::InstantiateVariableDefinition(VarDecl *Var) {
705  // FIXME: Implement this!
706}
707
708static bool isInstantiationOf(ASTContext &Ctx, NamedDecl *D, Decl *Other) {
709  if (D->getKind() != Other->getKind())
710    return false;
711
712  if (CXXRecordDecl *Record = dyn_cast<CXXRecordDecl>(Other))
713    return Ctx.getCanonicalDecl(Record->getInstantiatedFromMemberClass())
714             == Ctx.getCanonicalDecl(D);
715
716  if (FunctionDecl *Function = dyn_cast<FunctionDecl>(Other))
717    return Ctx.getCanonicalDecl(Function->getInstantiatedFromMemberFunction())
718             == Ctx.getCanonicalDecl(D);
719
720  if (EnumDecl *Enum = dyn_cast<EnumDecl>(Other))
721    return Ctx.getCanonicalDecl(Enum->getInstantiatedFromMemberEnum())
722             == Ctx.getCanonicalDecl(D);
723
724  // FIXME: How can we find instantiations of anonymous unions?
725
726  return D->getDeclName() && isa<NamedDecl>(Other) &&
727    D->getDeclName() == cast<NamedDecl>(Other)->getDeclName();
728}
729
730template<typename ForwardIterator>
731static NamedDecl *findInstantiationOf(ASTContext &Ctx,
732                                      NamedDecl *D,
733                                      ForwardIterator first,
734                                      ForwardIterator last) {
735  for (; first != last; ++first)
736    if (isInstantiationOf(Ctx, D, *first))
737      return cast<NamedDecl>(*first);
738
739  return 0;
740}
741
742/// \brief Find the instantiation of the given declaration within the
743/// current instantiation.
744///
745/// This routine is intended to be used when \p D is a declaration
746/// referenced from within a template, that needs to mapped into the
747/// corresponding declaration within an instantiation. For example,
748/// given:
749///
750/// \code
751/// template<typename T>
752/// struct X {
753///   enum Kind {
754///     KnownValue = sizeof(T)
755///   };
756///
757///   bool getKind() const { return KnownValue; }
758/// };
759///
760/// template struct X<int>;
761/// \endcode
762///
763/// In the instantiation of X<int>::getKind(), we need to map the
764/// EnumConstantDecl for KnownValue (which refers to
765/// X<T>::<Kind>::KnownValue) to its instantiation
766/// (X<int>::<Kind>::KnownValue). InstantiateCurrentDeclRef() performs
767/// this mapping from within the instantiation of X<int>.
768NamedDecl * Sema::InstantiateCurrentDeclRef(NamedDecl *D) {
769  DeclContext *ParentDC = D->getDeclContext();
770  if (isa<ParmVarDecl>(D) || ParentDC->isFunctionOrMethod()) {
771    // D is a local of some kind. Look into the map of local
772    // declarations to their instantiations.
773    return cast<NamedDecl>(CurrentInstantiationScope->getInstantiationOf(D));
774  }
775
776  if (NamedDecl *ParentDecl = dyn_cast<NamedDecl>(ParentDC)) {
777    ParentDecl = InstantiateCurrentDeclRef(ParentDecl);
778    if (!ParentDecl)
779      return 0;
780
781    ParentDC = cast<DeclContext>(ParentDecl);
782  }
783
784  if (ParentDC != D->getDeclContext()) {
785    // We performed some kind of instantiation in the parent context,
786    // so now we need to look into the instantiated parent context to
787    // find the instantiation of the declaration D.
788    NamedDecl *Result = 0;
789    if (D->getDeclName()) {
790      DeclContext::lookup_result Found
791        = ParentDC->lookup(Context, D->getDeclName());
792      Result = findInstantiationOf(Context, D, Found.first, Found.second);
793    } else {
794      // Since we don't have a name for the entity we're looking for,
795      // our only option is to walk through all of the declarations to
796      // find that name. This will occur in a few cases:
797      //
798      //   - anonymous struct/union within a template
799      //   - unnamed class/struct/union/enum within a template
800      //
801      // FIXME: Find a better way to find these instantiations!
802      Result = findInstantiationOf(Context, D,
803                                   ParentDC->decls_begin(Context),
804                                   ParentDC->decls_end(Context));
805    }
806    assert(Result && "Unable to find instantiation of declaration!");
807    D = Result;
808  }
809
810  if (CXXRecordDecl *Record = dyn_cast<CXXRecordDecl>(D))
811    if (ClassTemplateDecl *ClassTemplate
812          = Record->getDescribedClassTemplate()) {
813      // When the declaration D was parsed, it referred to the current
814      // instantiation. Therefore, look through the current context,
815      // which contains actual instantiations, to find the
816      // instantiation of the "current instantiation" that D refers
817      // to. Alternatively, we could just instantiate the
818      // injected-class-name with the current template arguments, but
819      // such an instantiation is far more expensive.
820      for (DeclContext *DC = CurContext; !DC->isFileContext();
821           DC = DC->getParent()) {
822        if (ClassTemplateSpecializationDecl *Spec
823              = dyn_cast<ClassTemplateSpecializationDecl>(DC))
824          if (Context.getCanonicalDecl(Spec->getSpecializedTemplate())
825              == Context.getCanonicalDecl(ClassTemplate))
826            return Spec;
827      }
828
829      assert(false &&
830             "Unable to find declaration for the current instantiation");
831    }
832
833  return D;
834}
835
836/// \brief Performs template instantiation for all implicit template
837/// instantiations we have seen until this point.
838void Sema::PerformPendingImplicitInstantiations() {
839  while (!PendingImplicitInstantiations.empty()) {
840    PendingImplicitInstantiation Inst = PendingImplicitInstantiations.front();
841    PendingImplicitInstantiations.pop();
842
843    if (FunctionDecl *Function = dyn_cast<FunctionDecl>(Inst.first))
844      if (!Function->getBody(Context))
845        InstantiateFunctionDefinition(/*FIXME:*/Inst.second, Function);
846
847    // FIXME: instantiation static member variables
848  }
849}
850