SemaTemplateInstantiateDecl.cpp revision 97fbaa2a38804268a024f1a104b43fcf8b4411b0 
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(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(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->getTypeSpecStartLoc(),
186                                            D->getAccess(),
187                                            0);
188  if (Field) {
189    if (Invalid)
190      Field->setInvalidDecl();
191
192    Owner->addDecl(Field);
193  }
194
195  return Field;
196}
197
198Decl *TemplateDeclInstantiator::VisitStaticAssertDecl(StaticAssertDecl *D) {
199  Expr *AssertExpr = D->getAssertExpr();
200
201  // The expression in a static assertion is not potentially evaluated.
202  EnterExpressionEvaluationContext Unevaluated(SemaRef, Action::Unevaluated);
203
204  OwningExprResult InstantiatedAssertExpr
205    = SemaRef.InstantiateExpr(AssertExpr, TemplateArgs);
206  if (InstantiatedAssertExpr.isInvalid())
207    return 0;
208
209  OwningExprResult Message = SemaRef.Clone(D->getMessage());
210  Decl *StaticAssert
211    = SemaRef.ActOnStaticAssertDeclaration(D->getLocation(),
212                                           move(InstantiatedAssertExpr),
213                                           move(Message)).getAs<Decl>();
214  return StaticAssert;
215}
216
217Decl *TemplateDeclInstantiator::VisitEnumDecl(EnumDecl *D) {
218  EnumDecl *Enum = EnumDecl::Create(SemaRef.Context, Owner,
219                                    D->getLocation(), D->getIdentifier(),
220                                    /*PrevDecl=*/0);
221  Enum->setInstantiationOfMemberEnum(D);
222  Enum->setAccess(D->getAccess());
223  Owner->addDecl(Enum);
224  Enum->startDefinition();
225
226  llvm::SmallVector<Sema::DeclPtrTy, 4> Enumerators;
227
228  EnumConstantDecl *LastEnumConst = 0;
229  for (EnumDecl::enumerator_iterator EC = D->enumerator_begin(),
230         ECEnd = D->enumerator_end();
231       EC != ECEnd; ++EC) {
232    // The specified value for the enumerator.
233    OwningExprResult Value = SemaRef.Owned((Expr *)0);
234    if (Expr *UninstValue = EC->getInitExpr()) {
235      // The enumerator's value expression is not potentially evaluated.
236      EnterExpressionEvaluationContext Unevaluated(SemaRef,
237                                                   Action::Unevaluated);
238
239      Value = SemaRef.InstantiateExpr(UninstValue, TemplateArgs);
240    }
241
242    // Drop the initial value and continue.
243    bool isInvalid = false;
244    if (Value.isInvalid()) {
245      Value = SemaRef.Owned((Expr *)0);
246      isInvalid = true;
247    }
248
249    EnumConstantDecl *EnumConst
250      = SemaRef.CheckEnumConstant(Enum, LastEnumConst,
251                                  EC->getLocation(), EC->getIdentifier(),
252                                  move(Value));
253
254    if (isInvalid) {
255      if (EnumConst)
256        EnumConst->setInvalidDecl();
257      Enum->setInvalidDecl();
258    }
259
260    if (EnumConst) {
261      Enum->addDecl(EnumConst);
262      Enumerators.push_back(Sema::DeclPtrTy::make(EnumConst));
263      LastEnumConst = EnumConst;
264    }
265  }
266
267  // FIXME: Fixup LBraceLoc and RBraceLoc
268  SemaRef.ActOnEnumBody(Enum->getLocation(), SourceLocation(), SourceLocation(),
269                        Sema::DeclPtrTy::make(Enum),
270                        &Enumerators[0], Enumerators.size());
271
272  return Enum;
273}
274
275Decl *TemplateDeclInstantiator::VisitEnumConstantDecl(EnumConstantDecl *D) {
276  assert(false && "EnumConstantDecls can only occur within EnumDecls.");
277  return 0;
278}
279
280Decl *TemplateDeclInstantiator::VisitCXXRecordDecl(CXXRecordDecl *D) {
281  CXXRecordDecl *PrevDecl = 0;
282  if (D->isInjectedClassName())
283    PrevDecl = cast<CXXRecordDecl>(Owner);
284
285  CXXRecordDecl *Record
286    = CXXRecordDecl::Create(SemaRef.Context, D->getTagKind(), Owner,
287                            D->getLocation(), D->getIdentifier(), PrevDecl);
288  Record->setImplicit(D->isImplicit());
289  Record->setAccess(D->getAccess());
290  if (!D->isInjectedClassName())
291    Record->setInstantiationOfMemberClass(D);
292
293  Owner->addDecl(Record);
294  return Record;
295}
296
297Decl *TemplateDeclInstantiator::VisitFunctionDecl(FunctionDecl *D) {
298  // Check whether there is already a function template specialization for
299  // this declaration.
300  FunctionTemplateDecl *FunctionTemplate = D->getDescribedFunctionTemplate();
301  void *InsertPos = 0;
302  if (FunctionTemplate) {
303    llvm::FoldingSetNodeID ID;
304    FunctionTemplateSpecializationInfo::Profile(ID,
305                                          TemplateArgs.getFlatArgumentList(),
306                                                TemplateArgs.flat_size());
307
308    FunctionTemplateSpecializationInfo *Info
309      = FunctionTemplate->getSpecializations().FindNodeOrInsertPos(ID,
310                                                                   InsertPos);
311
312    // If we already have a function template specialization, return it.
313    if (Info)
314      return Info->Function;
315  }
316
317  Sema::LocalInstantiationScope Scope(SemaRef);
318
319  llvm::SmallVector<ParmVarDecl *, 4> Params;
320  QualType T = InstantiateFunctionType(D, Params);
321  if (T.isNull())
322    return 0;
323
324  // Build the instantiated method declaration.
325  FunctionDecl *Function
326    = FunctionDecl::Create(SemaRef.Context, Owner, D->getLocation(),
327                           D->getDeclName(), T, D->getStorageClass(),
328                           D->isInline(), D->hasWrittenPrototype(),
329                           D->getTypeSpecStartLoc());
330
331  // FIXME: friend functions
332
333  // Attach the parameters
334  for (unsigned P = 0; P < Params.size(); ++P)
335    Params[P]->setOwningFunction(Function);
336  Function->setParams(SemaRef.Context, Params.data(), Params.size());
337
338  if (InitFunctionInstantiation(Function, D))
339    Function->setInvalidDecl();
340
341  bool Redeclaration = false;
342  bool OverloadableAttrRequired = false;
343  NamedDecl *PrevDecl = 0;
344  SemaRef.CheckFunctionDeclaration(Function, PrevDecl, Redeclaration,
345                                   /*FIXME:*/OverloadableAttrRequired);
346
347  if (FunctionTemplate) {
348    // Record this function template specialization.
349    Function->setFunctionTemplateSpecialization(SemaRef.Context,
350                                                FunctionTemplate,
351                                                &TemplateArgs,
352                                                InsertPos);
353   }
354
355  return Function;
356}
357
358Decl *TemplateDeclInstantiator::VisitCXXMethodDecl(CXXMethodDecl *D) {
359  // FIXME: Look for existing, explicit specializations.
360  Sema::LocalInstantiationScope Scope(SemaRef);
361
362  llvm::SmallVector<ParmVarDecl *, 4> Params;
363  QualType T = InstantiateFunctionType(D, Params);
364  if (T.isNull())
365    return 0;
366
367  // Build the instantiated method declaration.
368  CXXRecordDecl *Record = cast<CXXRecordDecl>(Owner);
369  CXXMethodDecl *Method
370    = CXXMethodDecl::Create(SemaRef.Context, Record, D->getLocation(),
371                            D->getDeclName(), T, D->isStatic(),
372                            D->isInline());
373  Method->setInstantiationOfMemberFunction(D);
374
375  // Attach the parameters
376  for (unsigned P = 0; P < Params.size(); ++P)
377    Params[P]->setOwningFunction(Method);
378  Method->setParams(SemaRef.Context, Params.data(), Params.size());
379
380  if (InitMethodInstantiation(Method, D))
381    Method->setInvalidDecl();
382
383  NamedDecl *PrevDecl
384    = SemaRef.LookupQualifiedName(Owner, Method->getDeclName(),
385                                  Sema::LookupOrdinaryName, true);
386  // In C++, the previous declaration we find might be a tag type
387  // (class or enum). In this case, the new declaration will hide the
388  // tag type. Note that this does does not apply if we're declaring a
389  // typedef (C++ [dcl.typedef]p4).
390  if (PrevDecl && PrevDecl->getIdentifierNamespace() == Decl::IDNS_Tag)
391    PrevDecl = 0;
392  bool Redeclaration = false;
393  bool OverloadableAttrRequired = false;
394  SemaRef.CheckFunctionDeclaration(Method, PrevDecl, Redeclaration,
395                                   /*FIXME:*/OverloadableAttrRequired);
396
397  if (!Method->isInvalidDecl() || !PrevDecl)
398    Owner->addDecl(Method);
399  return Method;
400}
401
402Decl *TemplateDeclInstantiator::VisitCXXConstructorDecl(CXXConstructorDecl *D) {
403  // FIXME: Look for existing, explicit specializations.
404  Sema::LocalInstantiationScope Scope(SemaRef);
405
406  llvm::SmallVector<ParmVarDecl *, 4> Params;
407  QualType T = InstantiateFunctionType(D, Params);
408  if (T.isNull())
409    return 0;
410
411  // Build the instantiated method declaration.
412  CXXRecordDecl *Record = cast<CXXRecordDecl>(Owner);
413  QualType ClassTy = SemaRef.Context.getTypeDeclType(Record);
414  DeclarationName Name
415    = SemaRef.Context.DeclarationNames.getCXXConstructorName(
416                                 SemaRef.Context.getCanonicalType(ClassTy));
417  CXXConstructorDecl *Constructor
418    = CXXConstructorDecl::Create(SemaRef.Context, Record, D->getLocation(),
419                                 Name, T, D->isExplicit(), D->isInline(),
420                                 false);
421  Constructor->setInstantiationOfMemberFunction(D);
422
423  // Attach the parameters
424  for (unsigned P = 0; P < Params.size(); ++P)
425    Params[P]->setOwningFunction(Constructor);
426  Constructor->setParams(SemaRef.Context, Params.data(), Params.size());
427
428  if (InitMethodInstantiation(Constructor, D))
429    Constructor->setInvalidDecl();
430
431  NamedDecl *PrevDecl
432    = SemaRef.LookupQualifiedName(Owner, Name, Sema::LookupOrdinaryName, true);
433
434  // In C++, the previous declaration we find might be a tag type
435  // (class or enum). In this case, the new declaration will hide the
436  // tag type. Note that this does does not apply if we're declaring a
437  // typedef (C++ [dcl.typedef]p4).
438  if (PrevDecl && PrevDecl->getIdentifierNamespace() == Decl::IDNS_Tag)
439    PrevDecl = 0;
440  bool Redeclaration = false;
441  bool OverloadableAttrRequired = false;
442  SemaRef.CheckFunctionDeclaration(Constructor, PrevDecl, Redeclaration,
443                                   /*FIXME:*/OverloadableAttrRequired);
444
445  Record->addedConstructor(SemaRef.Context, Constructor);
446  Owner->addDecl(Constructor);
447  return Constructor;
448}
449
450Decl *TemplateDeclInstantiator::VisitCXXDestructorDecl(CXXDestructorDecl *D) {
451  // FIXME: Look for existing, explicit specializations.
452  Sema::LocalInstantiationScope Scope(SemaRef);
453
454  llvm::SmallVector<ParmVarDecl *, 4> Params;
455  QualType T = InstantiateFunctionType(D, Params);
456  if (T.isNull())
457    return 0;
458  assert(Params.size() == 0 && "Destructor with parameters?");
459
460  // Build the instantiated destructor declaration.
461  CXXRecordDecl *Record = cast<CXXRecordDecl>(Owner);
462  QualType ClassTy =
463    SemaRef.Context.getCanonicalType(SemaRef.Context.getTypeDeclType(Record));
464  CXXDestructorDecl *Destructor
465    = CXXDestructorDecl::Create(SemaRef.Context, Record,
466                                D->getLocation(),
467             SemaRef.Context.DeclarationNames.getCXXDestructorName(ClassTy),
468                                T, D->isInline(), false);
469  Destructor->setInstantiationOfMemberFunction(D);
470  if (InitMethodInstantiation(Destructor, D))
471    Destructor->setInvalidDecl();
472
473  bool Redeclaration = false;
474  bool OverloadableAttrRequired = false;
475  NamedDecl *PrevDecl = 0;
476  SemaRef.CheckFunctionDeclaration(Destructor, PrevDecl, Redeclaration,
477                                   /*FIXME:*/OverloadableAttrRequired);
478  Owner->addDecl(Destructor);
479  return Destructor;
480}
481
482Decl *TemplateDeclInstantiator::VisitCXXConversionDecl(CXXConversionDecl *D) {
483  // FIXME: Look for existing, explicit specializations.
484  Sema::LocalInstantiationScope Scope(SemaRef);
485
486  llvm::SmallVector<ParmVarDecl *, 4> Params;
487  QualType T = InstantiateFunctionType(D, Params);
488  if (T.isNull())
489    return 0;
490  assert(Params.size() == 0 && "Destructor with parameters?");
491
492  // Build the instantiated conversion declaration.
493  CXXRecordDecl *Record = cast<CXXRecordDecl>(Owner);
494  QualType ClassTy = SemaRef.Context.getTypeDeclType(Record);
495  QualType ConvTy
496    = SemaRef.Context.getCanonicalType(T->getAsFunctionType()->getResultType());
497  CXXConversionDecl *Conversion
498    = CXXConversionDecl::Create(SemaRef.Context, Record,
499                                D->getLocation(),
500         SemaRef.Context.DeclarationNames.getCXXConversionFunctionName(ConvTy),
501                                T, D->isInline(), D->isExplicit());
502  Conversion->setInstantiationOfMemberFunction(D);
503  if (InitMethodInstantiation(Conversion, D))
504    Conversion->setInvalidDecl();
505
506  bool Redeclaration = false;
507  bool OverloadableAttrRequired = false;
508  NamedDecl *PrevDecl = 0;
509  SemaRef.CheckFunctionDeclaration(Conversion, PrevDecl, Redeclaration,
510                                   /*FIXME:*/OverloadableAttrRequired);
511  Owner->addDecl(Conversion);
512  return Conversion;
513}
514
515ParmVarDecl *TemplateDeclInstantiator::VisitParmVarDecl(ParmVarDecl *D) {
516  QualType OrigT = SemaRef.InstantiateType(D->getOriginalType(), TemplateArgs,
517                                           D->getLocation(), D->getDeclName());
518  if (OrigT.isNull())
519    return 0;
520
521  QualType T = SemaRef.adjustParameterType(OrigT);
522
523  if (D->getDefaultArg()) {
524    // FIXME: Leave a marker for "uninstantiated" default
525    // arguments. They only get instantiated on demand at the call
526    // site.
527    unsigned DiagID = SemaRef.Diags.getCustomDiagID(Diagnostic::Warning,
528        "sorry, dropping default argument during template instantiation");
529    SemaRef.Diag(D->getDefaultArg()->getSourceRange().getBegin(), DiagID)
530      << D->getDefaultArg()->getSourceRange();
531  }
532
533  // Allocate the parameter
534  ParmVarDecl *Param = 0;
535  if (T == OrigT)
536    Param = ParmVarDecl::Create(SemaRef.Context, Owner, D->getLocation(),
537                                D->getIdentifier(), T, D->getStorageClass(),
538                                0);
539  else
540    Param = OriginalParmVarDecl::Create(SemaRef.Context, Owner,
541                                        D->getLocation(), D->getIdentifier(),
542                                        T, OrigT, D->getStorageClass(), 0);
543
544  // Note: we don't try to instantiate function parameters until after
545  // we've instantiated the function's type. Therefore, we don't have
546  // to check for 'void' parameter types here.
547  SemaRef.CurrentInstantiationScope->InstantiatedLocal(D, Param);
548  return Param;
549}
550
551Decl *
552TemplateDeclInstantiator::VisitOriginalParmVarDecl(OriginalParmVarDecl *D) {
553  // Since parameter types can decay either before or after
554  // instantiation, we simply treat OriginalParmVarDecls as
555  // ParmVarDecls the same way, and create one or the other depending
556  // on what happens after template instantiation.
557  return VisitParmVarDecl(D);
558}
559
560Decl *Sema::InstantiateDecl(Decl *D, DeclContext *Owner,
561                            const TemplateArgumentList &TemplateArgs) {
562  TemplateDeclInstantiator Instantiator(*this, Owner, TemplateArgs);
563  return Instantiator.Visit(D);
564}
565
566/// \brief Instantiates the type of the given function, including
567/// instantiating all of the function parameters.
568///
569/// \param D The function that we will be instantiated
570///
571/// \param Params the instantiated parameter declarations
572
573/// \returns the instantiated function's type if successfull, a NULL
574/// type if there was an error.
575QualType
576TemplateDeclInstantiator::InstantiateFunctionType(FunctionDecl *D,
577                              llvm::SmallVectorImpl<ParmVarDecl *> &Params) {
578  bool InvalidDecl = false;
579
580  // Instantiate the function parameters
581  TemplateDeclInstantiator ParamInstantiator(SemaRef, 0, TemplateArgs);
582  llvm::SmallVector<QualType, 4> ParamTys;
583  for (FunctionDecl::param_iterator P = D->param_begin(),
584                                 PEnd = D->param_end();
585       P != PEnd; ++P) {
586    if (ParmVarDecl *PInst = ParamInstantiator.VisitParmVarDecl(*P)) {
587      if (PInst->getType()->isVoidType()) {
588        SemaRef.Diag(PInst->getLocation(), diag::err_param_with_void_type);
589        PInst->setInvalidDecl();
590      }
591      else if (SemaRef.RequireNonAbstractType(PInst->getLocation(),
592                                              PInst->getType(),
593                                              diag::err_abstract_type_in_decl,
594                                              Sema::AbstractParamType))
595        PInst->setInvalidDecl();
596
597      Params.push_back(PInst);
598      ParamTys.push_back(PInst->getType());
599
600      if (PInst->isInvalidDecl())
601        InvalidDecl = true;
602    } else
603      InvalidDecl = true;
604  }
605
606  // FIXME: Deallocate dead declarations.
607  if (InvalidDecl)
608    return QualType();
609
610  const FunctionProtoType *Proto = D->getType()->getAsFunctionProtoType();
611  assert(Proto && "Missing prototype?");
612  QualType ResultType
613    = SemaRef.InstantiateType(Proto->getResultType(), TemplateArgs,
614                              D->getLocation(), D->getDeclName());
615  if (ResultType.isNull())
616    return QualType();
617
618  return SemaRef.BuildFunctionType(ResultType, ParamTys.data(), ParamTys.size(),
619                                   Proto->isVariadic(), Proto->getTypeQuals(),
620                                   D->getLocation(), D->getDeclName());
621}
622
623/// \brief Initializes the common fields of an instantiation function
624/// declaration (New) from the corresponding fields of its template (Tmpl).
625///
626/// \returns true if there was an error
627bool
628TemplateDeclInstantiator::InitFunctionInstantiation(FunctionDecl *New,
629                                                    FunctionDecl *Tmpl) {
630  if (Tmpl->isDeleted())
631    New->setDeleted();
632
633  // If we are performing substituting explicitly-specified template arguments
634  // or deduced template arguments into a function template and we reach this
635  // point, we are now past the point where SFINAE applies and have committed
636  // to keeping the new function template specialization. We therefore
637  // convert the active template instantiation for the function template
638  // into a template instantiation for this specific function template
639  // specialization, which is not a SFINAE context, so that we diagnose any
640  // further errors in the declaration itself.
641  typedef Sema::ActiveTemplateInstantiation ActiveInstType;
642  ActiveInstType &ActiveInst = SemaRef.ActiveTemplateInstantiations.back();
643  if (ActiveInst.Kind == ActiveInstType::ExplicitTemplateArgumentSubstitution ||
644      ActiveInst.Kind == ActiveInstType::DeducedTemplateArgumentSubstitution) {
645    if (FunctionTemplateDecl *FunTmpl
646          = dyn_cast<FunctionTemplateDecl>((Decl *)ActiveInst.Entity)) {
647      assert(FunTmpl->getTemplatedDecl() == Tmpl &&
648             "Deduction from the wrong function template?");
649      (void) FunTmpl;
650      ActiveInst.Kind = ActiveInstType::TemplateInstantiation;
651      ActiveInst.Entity = reinterpret_cast<uintptr_t>(New);
652    }
653  }
654
655  return false;
656}
657
658/// \brief Initializes common fields of an instantiated method
659/// declaration (New) from the corresponding fields of its template
660/// (Tmpl).
661///
662/// \returns true if there was an error
663bool
664TemplateDeclInstantiator::InitMethodInstantiation(CXXMethodDecl *New,
665                                                  CXXMethodDecl *Tmpl) {
666  if (InitFunctionInstantiation(New, Tmpl))
667    return true;
668
669  CXXRecordDecl *Record = cast<CXXRecordDecl>(Owner);
670  New->setAccess(Tmpl->getAccess());
671  if (Tmpl->isVirtualAsWritten()) {
672    New->setVirtualAsWritten(true);
673    Record->setAggregate(false);
674    Record->setPOD(false);
675    Record->setPolymorphic(true);
676  }
677  if (Tmpl->isPure()) {
678    New->setPure();
679    Record->setAbstract(true);
680  }
681
682  // FIXME: attributes
683  // FIXME: New needs a pointer to Tmpl
684  return false;
685}
686
687/// \brief Instantiate the definition of the given function from its
688/// template.
689///
690/// \param PointOfInstantiation the point at which the instantiation was
691/// required. Note that this is not precisely a "point of instantiation"
692/// for the function, but it's close.
693///
694/// \param Function the already-instantiated declaration of a
695/// function template specialization or member function of a class template
696/// specialization.
697///
698/// \param Recursive if true, recursively instantiates any functions that
699/// are required by this instantiation.
700void Sema::InstantiateFunctionDefinition(SourceLocation PointOfInstantiation,
701                                         FunctionDecl *Function,
702                                         bool Recursive) {
703  if (Function->isInvalidDecl())
704    return;
705
706  assert(!Function->getBody() && "Already instantiated!");
707
708  // Find the function body that we'll be substituting.
709  const FunctionDecl *PatternDecl = 0;
710  if (FunctionTemplateDecl *Primary = Function->getPrimaryTemplate())
711    PatternDecl = Primary->getTemplatedDecl();
712  else
713    PatternDecl = Function->getInstantiatedFromMemberFunction();
714  Stmt *Pattern = 0;
715  if (PatternDecl)
716    Pattern = PatternDecl->getBody(PatternDecl);
717
718  if (!Pattern)
719    return;
720
721  InstantiatingTemplate Inst(*this, PointOfInstantiation, Function);
722  if (Inst)
723    return;
724
725  // If we're performing recursive template instantiation, create our own
726  // queue of pending implicit instantiations that we will instantiate later,
727  // while we're still within our own instantiation context.
728  std::deque<PendingImplicitInstantiation> SavedPendingImplicitInstantiations;
729  if (Recursive)
730    PendingImplicitInstantiations.swap(SavedPendingImplicitInstantiations);
731
732  ActOnStartOfFunctionDef(0, DeclPtrTy::make(Function));
733
734  // Introduce a new scope where local variable instantiations will be
735  // recorded.
736  LocalInstantiationScope Scope(*this);
737
738  // Introduce the instantiated function parameters into the local
739  // instantiation scope.
740  for (unsigned I = 0, N = PatternDecl->getNumParams(); I != N; ++I)
741    Scope.InstantiatedLocal(PatternDecl->getParamDecl(I),
742                            Function->getParamDecl(I));
743
744  // Enter the scope of this instantiation. We don't use
745  // PushDeclContext because we don't have a scope.
746  DeclContext *PreviousContext = CurContext;
747  CurContext = Function;
748
749  // Instantiate the function body.
750  OwningStmtResult Body
751    = InstantiateStmt(Pattern, getTemplateInstantiationArgs(Function));
752
753  ActOnFinishFunctionBody(DeclPtrTy::make(Function), move(Body),
754                          /*IsInstantiation=*/true);
755
756  CurContext = PreviousContext;
757
758  DeclGroupRef DG(Function);
759  Consumer.HandleTopLevelDecl(DG);
760
761  if (Recursive) {
762    // Instantiate any pending implicit instantiations found during the
763    // instantiation of this template.
764    PerformPendingImplicitInstantiations();
765
766    // Restore the set of pending implicit instantiations.
767    PendingImplicitInstantiations.swap(SavedPendingImplicitInstantiations);
768  }
769}
770
771/// \brief Instantiate the definition of the given variable from its
772/// template.
773///
774/// \param Var the already-instantiated declaration of a variable.
775void Sema::InstantiateVariableDefinition(VarDecl *Var) {
776  // FIXME: Implement this!
777}
778
779static bool isInstantiationOf(ASTContext &Ctx, NamedDecl *D, Decl *Other) {
780  if (D->getKind() != Other->getKind())
781    return false;
782
783  if (CXXRecordDecl *Record = dyn_cast<CXXRecordDecl>(Other))
784    return Record->getInstantiatedFromMemberClass()->getCanonicalDecl()
785             == D->getCanonicalDecl();
786
787  if (FunctionDecl *Function = dyn_cast<FunctionDecl>(Other))
788    return Function->getInstantiatedFromMemberFunction()->getCanonicalDecl()
789             == D->getCanonicalDecl();
790
791  if (EnumDecl *Enum = dyn_cast<EnumDecl>(Other))
792    return Enum->getInstantiatedFromMemberEnum()->getCanonicalDecl()
793             == D->getCanonicalDecl();
794
795  // FIXME: How can we find instantiations of anonymous unions?
796
797  return D->getDeclName() && isa<NamedDecl>(Other) &&
798    D->getDeclName() == cast<NamedDecl>(Other)->getDeclName();
799}
800
801template<typename ForwardIterator>
802static NamedDecl *findInstantiationOf(ASTContext &Ctx,
803                                      NamedDecl *D,
804                                      ForwardIterator first,
805                                      ForwardIterator last) {
806  for (; first != last; ++first)
807    if (isInstantiationOf(Ctx, D, *first))
808      return cast<NamedDecl>(*first);
809
810  return 0;
811}
812
813/// \brief Find the instantiation of the given declaration within the
814/// current instantiation.
815///
816/// This routine is intended to be used when \p D is a declaration
817/// referenced from within a template, that needs to mapped into the
818/// corresponding declaration within an instantiation. For example,
819/// given:
820///
821/// \code
822/// template<typename T>
823/// struct X {
824///   enum Kind {
825///     KnownValue = sizeof(T)
826///   };
827///
828///   bool getKind() const { return KnownValue; }
829/// };
830///
831/// template struct X<int>;
832/// \endcode
833///
834/// In the instantiation of X<int>::getKind(), we need to map the
835/// EnumConstantDecl for KnownValue (which refers to
836/// X<T>::<Kind>::KnownValue) to its instantiation
837/// (X<int>::<Kind>::KnownValue). InstantiateCurrentDeclRef() performs
838/// this mapping from within the instantiation of X<int>.
839NamedDecl * Sema::InstantiateCurrentDeclRef(NamedDecl *D) {
840  DeclContext *ParentDC = D->getDeclContext();
841  if (isa<ParmVarDecl>(D) || ParentDC->isFunctionOrMethod()) {
842    // D is a local of some kind. Look into the map of local
843    // declarations to their instantiations.
844    return cast<NamedDecl>(CurrentInstantiationScope->getInstantiationOf(D));
845  }
846
847  if (NamedDecl *ParentDecl = dyn_cast<NamedDecl>(ParentDC)) {
848    ParentDecl = InstantiateCurrentDeclRef(ParentDecl);
849    if (!ParentDecl)
850      return 0;
851
852    ParentDC = cast<DeclContext>(ParentDecl);
853  }
854
855  if (ParentDC != D->getDeclContext()) {
856    // We performed some kind of instantiation in the parent context,
857    // so now we need to look into the instantiated parent context to
858    // find the instantiation of the declaration D.
859    NamedDecl *Result = 0;
860    if (D->getDeclName()) {
861      DeclContext::lookup_result Found = ParentDC->lookup(D->getDeclName());
862      Result = findInstantiationOf(Context, D, Found.first, Found.second);
863    } else {
864      // Since we don't have a name for the entity we're looking for,
865      // our only option is to walk through all of the declarations to
866      // find that name. This will occur in a few cases:
867      //
868      //   - anonymous struct/union within a template
869      //   - unnamed class/struct/union/enum within a template
870      //
871      // FIXME: Find a better way to find these instantiations!
872      Result = findInstantiationOf(Context, D,
873                                   ParentDC->decls_begin(),
874                                   ParentDC->decls_end());
875    }
876    assert(Result && "Unable to find instantiation of declaration!");
877    D = Result;
878  }
879
880  if (CXXRecordDecl *Record = dyn_cast<CXXRecordDecl>(D))
881    if (ClassTemplateDecl *ClassTemplate
882          = Record->getDescribedClassTemplate()) {
883      // When the declaration D was parsed, it referred to the current
884      // instantiation. Therefore, look through the current context,
885      // which contains actual instantiations, to find the
886      // instantiation of the "current instantiation" that D refers
887      // to. Alternatively, we could just instantiate the
888      // injected-class-name with the current template arguments, but
889      // such an instantiation is far more expensive.
890      for (DeclContext *DC = CurContext; !DC->isFileContext();
891           DC = DC->getParent()) {
892        if (ClassTemplateSpecializationDecl *Spec
893              = dyn_cast<ClassTemplateSpecializationDecl>(DC))
894          if (Spec->getSpecializedTemplate()->getCanonicalDecl()
895              == ClassTemplate->getCanonicalDecl())
896            return Spec;
897      }
898
899      assert(false &&
900             "Unable to find declaration for the current instantiation");
901    }
902
903  return D;
904}
905
906/// \brief Performs template instantiation for all implicit template
907/// instantiations we have seen until this point.
908void Sema::PerformPendingImplicitInstantiations() {
909  while (!PendingImplicitInstantiations.empty()) {
910    PendingImplicitInstantiation Inst = PendingImplicitInstantiations.front();
911    PendingImplicitInstantiations.pop_front();
912
913    if (FunctionDecl *Function = dyn_cast<FunctionDecl>(Inst.first))
914      if (!Function->getBody())
915        InstantiateFunctionDefinition(/*FIXME:*/Inst.second, Function, true);
916
917    // FIXME: instantiate static member variables
918  }
919}
920