SemaTemplateInstantiateDecl.cpp revision 90fc78e83a12eaee80a3d0a174429529b7f82e85 
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  // If we are instantiating a static data member defined
124  // out-of-line, the instantiation will have the same lexical
125  // context (which will be a namespace scope) as the template.
126  if (D->isOutOfLine())
127    Var->setLexicalDeclContext(D->getLexicalDeclContext());
128
129  // FIXME: In theory, we could have a previous declaration for variables that
130  // are not static data members.
131  bool Redeclaration = false;
132  SemaRef.CheckVariableDeclaration(Var, 0, Redeclaration);
133
134  if (D->isOutOfLine()) {
135    D->getLexicalDeclContext()->addDecl(Var);
136    Owner->makeDeclVisibleInContext(Var);
137  } else {
138    Owner->addDecl(Var);
139  }
140
141  if (D->getInit()) {
142    OwningExprResult Init
143      = SemaRef.InstantiateExpr(D->getInit(), TemplateArgs);
144    if (Init.isInvalid())
145      Var->setInvalidDecl();
146    else
147      SemaRef.AddInitializerToDecl(Sema::DeclPtrTy::make(Var), move(Init),
148                                   D->hasCXXDirectInitializer());
149  } else if (!Var->isStaticDataMember() || Var->isOutOfLine())
150    SemaRef.ActOnUninitializedDecl(Sema::DeclPtrTy::make(Var), false);
151
152  // Link instantiations of static data members back to the template from
153  // which they were instantiated.
154  if (Var->isStaticDataMember())
155    SemaRef.Context.setInstantiatedFromStaticDataMember(Var, D);
156
157  return Var;
158}
159
160Decl *TemplateDeclInstantiator::VisitFieldDecl(FieldDecl *D) {
161  bool Invalid = false;
162  QualType T = D->getType();
163  if (T->isDependentType())  {
164    T = SemaRef.InstantiateType(T, TemplateArgs,
165                                D->getLocation(), D->getDeclName());
166    if (!T.isNull() && T->isFunctionType()) {
167      // C++ [temp.arg.type]p3:
168      //   If a declaration acquires a function type through a type
169      //   dependent on a template-parameter and this causes a
170      //   declaration that does not use the syntactic form of a
171      //   function declarator to have function type, the program is
172      //   ill-formed.
173      SemaRef.Diag(D->getLocation(), diag::err_field_instantiates_to_function)
174        << T;
175      T = QualType();
176      Invalid = true;
177    }
178  }
179
180  Expr *BitWidth = D->getBitWidth();
181  if (Invalid)
182    BitWidth = 0;
183  else if (BitWidth) {
184    // The bit-width expression is not potentially evaluated.
185    EnterExpressionEvaluationContext Unevaluated(SemaRef, Action::Unevaluated);
186
187    OwningExprResult InstantiatedBitWidth
188      = SemaRef.InstantiateExpr(BitWidth, TemplateArgs);
189    if (InstantiatedBitWidth.isInvalid()) {
190      Invalid = true;
191      BitWidth = 0;
192    } else
193      BitWidth = InstantiatedBitWidth.takeAs<Expr>();
194  }
195
196  FieldDecl *Field = SemaRef.CheckFieldDecl(D->getDeclName(), T,
197                                            cast<RecordDecl>(Owner),
198                                            D->getLocation(),
199                                            D->isMutable(),
200                                            BitWidth,
201                                            D->getTypeSpecStartLoc(),
202                                            D->getAccess(),
203                                            0);
204  if (Field) {
205    if (Invalid)
206      Field->setInvalidDecl();
207
208    Owner->addDecl(Field);
209  }
210
211  return Field;
212}
213
214Decl *TemplateDeclInstantiator::VisitStaticAssertDecl(StaticAssertDecl *D) {
215  Expr *AssertExpr = D->getAssertExpr();
216
217  // The expression in a static assertion is not potentially evaluated.
218  EnterExpressionEvaluationContext Unevaluated(SemaRef, Action::Unevaluated);
219
220  OwningExprResult InstantiatedAssertExpr
221    = SemaRef.InstantiateExpr(AssertExpr, TemplateArgs);
222  if (InstantiatedAssertExpr.isInvalid())
223    return 0;
224
225  OwningExprResult Message = SemaRef.Clone(D->getMessage());
226  Decl *StaticAssert
227    = SemaRef.ActOnStaticAssertDeclaration(D->getLocation(),
228                                           move(InstantiatedAssertExpr),
229                                           move(Message)).getAs<Decl>();
230  return StaticAssert;
231}
232
233Decl *TemplateDeclInstantiator::VisitEnumDecl(EnumDecl *D) {
234  EnumDecl *Enum = EnumDecl::Create(SemaRef.Context, Owner,
235                                    D->getLocation(), D->getIdentifier(),
236                                    D->getTagKeywordLoc(),
237                                    /*PrevDecl=*/0);
238  Enum->setInstantiationOfMemberEnum(D);
239  Enum->setAccess(D->getAccess());
240  Owner->addDecl(Enum);
241  Enum->startDefinition();
242
243  llvm::SmallVector<Sema::DeclPtrTy, 4> Enumerators;
244
245  EnumConstantDecl *LastEnumConst = 0;
246  for (EnumDecl::enumerator_iterator EC = D->enumerator_begin(),
247         ECEnd = D->enumerator_end();
248       EC != ECEnd; ++EC) {
249    // The specified value for the enumerator.
250    OwningExprResult Value = SemaRef.Owned((Expr *)0);
251    if (Expr *UninstValue = EC->getInitExpr()) {
252      // The enumerator's value expression is not potentially evaluated.
253      EnterExpressionEvaluationContext Unevaluated(SemaRef,
254                                                   Action::Unevaluated);
255
256      Value = SemaRef.InstantiateExpr(UninstValue, TemplateArgs);
257    }
258
259    // Drop the initial value and continue.
260    bool isInvalid = false;
261    if (Value.isInvalid()) {
262      Value = SemaRef.Owned((Expr *)0);
263      isInvalid = true;
264    }
265
266    EnumConstantDecl *EnumConst
267      = SemaRef.CheckEnumConstant(Enum, LastEnumConst,
268                                  EC->getLocation(), EC->getIdentifier(),
269                                  move(Value));
270
271    if (isInvalid) {
272      if (EnumConst)
273        EnumConst->setInvalidDecl();
274      Enum->setInvalidDecl();
275    }
276
277    if (EnumConst) {
278      Enum->addDecl(EnumConst);
279      Enumerators.push_back(Sema::DeclPtrTy::make(EnumConst));
280      LastEnumConst = EnumConst;
281    }
282  }
283
284  // FIXME: Fixup LBraceLoc and RBraceLoc
285  SemaRef.ActOnEnumBody(Enum->getLocation(), SourceLocation(), SourceLocation(),
286                        Sema::DeclPtrTy::make(Enum),
287                        &Enumerators[0], Enumerators.size());
288
289  return Enum;
290}
291
292Decl *TemplateDeclInstantiator::VisitEnumConstantDecl(EnumConstantDecl *D) {
293  assert(false && "EnumConstantDecls can only occur within EnumDecls.");
294  return 0;
295}
296
297Decl *TemplateDeclInstantiator::VisitCXXRecordDecl(CXXRecordDecl *D) {
298  CXXRecordDecl *PrevDecl = 0;
299  if (D->isInjectedClassName())
300    PrevDecl = cast<CXXRecordDecl>(Owner);
301
302  CXXRecordDecl *Record
303    = CXXRecordDecl::Create(SemaRef.Context, D->getTagKind(), Owner,
304                            D->getLocation(), D->getIdentifier(),
305                            D->getTagKeywordLoc(), PrevDecl);
306  Record->setImplicit(D->isImplicit());
307  Record->setAccess(D->getAccess());
308  if (!D->isInjectedClassName())
309    Record->setInstantiationOfMemberClass(D);
310
311  Owner->addDecl(Record);
312  return Record;
313}
314
315Decl *TemplateDeclInstantiator::VisitFunctionDecl(FunctionDecl *D) {
316  // Check whether there is already a function template specialization for
317  // this declaration.
318  FunctionTemplateDecl *FunctionTemplate = D->getDescribedFunctionTemplate();
319  void *InsertPos = 0;
320  if (FunctionTemplate) {
321    llvm::FoldingSetNodeID ID;
322    FunctionTemplateSpecializationInfo::Profile(ID,
323                                          TemplateArgs.getFlatArgumentList(),
324                                                TemplateArgs.flat_size(),
325                                                SemaRef.Context);
326
327    FunctionTemplateSpecializationInfo *Info
328      = FunctionTemplate->getSpecializations().FindNodeOrInsertPos(ID,
329                                                                   InsertPos);
330
331    // If we already have a function template specialization, return it.
332    if (Info)
333      return Info->Function;
334  }
335
336  Sema::LocalInstantiationScope Scope(SemaRef);
337
338  llvm::SmallVector<ParmVarDecl *, 4> Params;
339  QualType T = InstantiateFunctionType(D, Params);
340  if (T.isNull())
341    return 0;
342
343  // Build the instantiated method declaration.
344  FunctionDecl *Function
345    = FunctionDecl::Create(SemaRef.Context, Owner, D->getLocation(),
346                           D->getDeclName(), T, D->getStorageClass(),
347                           D->isInline(), D->hasWrittenPrototype(),
348                           D->getTypeSpecStartLoc());
349
350  // FIXME: friend functions
351
352  // Attach the parameters
353  for (unsigned P = 0; P < Params.size(); ++P)
354    Params[P]->setOwningFunction(Function);
355  Function->setParams(SemaRef.Context, Params.data(), Params.size());
356
357  if (InitFunctionInstantiation(Function, D))
358    Function->setInvalidDecl();
359
360  bool Redeclaration = false;
361  bool OverloadableAttrRequired = false;
362  NamedDecl *PrevDecl = 0;
363  SemaRef.CheckFunctionDeclaration(Function, PrevDecl, Redeclaration,
364                                   /*FIXME:*/OverloadableAttrRequired);
365
366  if (FunctionTemplate) {
367    // Record this function template specialization.
368    Function->setFunctionTemplateSpecialization(SemaRef.Context,
369                                                FunctionTemplate,
370                                                &TemplateArgs,
371                                                InsertPos);
372   }
373
374  return Function;
375}
376
377Decl *TemplateDeclInstantiator::VisitCXXMethodDecl(CXXMethodDecl *D) {
378  // FIXME: Look for existing, explicit specializations.
379  Sema::LocalInstantiationScope Scope(SemaRef);
380
381  llvm::SmallVector<ParmVarDecl *, 4> Params;
382  QualType T = InstantiateFunctionType(D, Params);
383  if (T.isNull())
384    return 0;
385
386  // Build the instantiated method declaration.
387  CXXRecordDecl *Record = cast<CXXRecordDecl>(Owner);
388  CXXMethodDecl *Method
389    = CXXMethodDecl::Create(SemaRef.Context, Record, D->getLocation(),
390                            D->getDeclName(), T, D->isStatic(),
391                            D->isInline());
392  Method->setInstantiationOfMemberFunction(D);
393
394  // If we are instantiating a member function defined
395  // out-of-line, the instantiation will have the same lexical
396  // context (which will be a namespace scope) as the template.
397  if (D->isOutOfLine())
398    Method->setLexicalDeclContext(D->getLexicalDeclContext());
399
400  // Attach the parameters
401  for (unsigned P = 0; P < Params.size(); ++P)
402    Params[P]->setOwningFunction(Method);
403  Method->setParams(SemaRef.Context, Params.data(), Params.size());
404
405  if (InitMethodInstantiation(Method, D))
406    Method->setInvalidDecl();
407
408  NamedDecl *PrevDecl
409    = SemaRef.LookupQualifiedName(Owner, Method->getDeclName(),
410                                  Sema::LookupOrdinaryName, true);
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(Method, PrevDecl, Redeclaration,
420                                   /*FIXME:*/OverloadableAttrRequired);
421
422  if (!Method->isInvalidDecl() || !PrevDecl)
423    Owner->addDecl(Method);
424  return Method;
425}
426
427Decl *TemplateDeclInstantiator::VisitCXXConstructorDecl(CXXConstructorDecl *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
436  // Build the instantiated method declaration.
437  CXXRecordDecl *Record = cast<CXXRecordDecl>(Owner);
438  QualType ClassTy = SemaRef.Context.getTypeDeclType(Record);
439  DeclarationName Name
440    = SemaRef.Context.DeclarationNames.getCXXConstructorName(
441                                 SemaRef.Context.getCanonicalType(ClassTy));
442  CXXConstructorDecl *Constructor
443    = CXXConstructorDecl::Create(SemaRef.Context, Record, D->getLocation(),
444                                 Name, T, D->isExplicit(), D->isInline(),
445                                 false);
446  Constructor->setInstantiationOfMemberFunction(D);
447
448  // Attach the parameters
449  for (unsigned P = 0; P < Params.size(); ++P)
450    Params[P]->setOwningFunction(Constructor);
451  Constructor->setParams(SemaRef.Context, Params.data(), Params.size());
452
453  if (InitMethodInstantiation(Constructor, D))
454    Constructor->setInvalidDecl();
455
456  NamedDecl *PrevDecl
457    = SemaRef.LookupQualifiedName(Owner, Name, Sema::LookupOrdinaryName, true);
458
459  // In C++, the previous declaration we find might be a tag type
460  // (class or enum). In this case, the new declaration will hide the
461  // tag type. Note that this does does not apply if we're declaring a
462  // typedef (C++ [dcl.typedef]p4).
463  if (PrevDecl && PrevDecl->getIdentifierNamespace() == Decl::IDNS_Tag)
464    PrevDecl = 0;
465  bool Redeclaration = false;
466  bool OverloadableAttrRequired = false;
467  SemaRef.CheckFunctionDeclaration(Constructor, PrevDecl, Redeclaration,
468                                   /*FIXME:*/OverloadableAttrRequired);
469
470  Record->addedConstructor(SemaRef.Context, Constructor);
471  Owner->addDecl(Constructor);
472  return Constructor;
473}
474
475Decl *TemplateDeclInstantiator::VisitCXXDestructorDecl(CXXDestructorDecl *D) {
476  // FIXME: Look for existing, explicit specializations.
477  Sema::LocalInstantiationScope Scope(SemaRef);
478
479  llvm::SmallVector<ParmVarDecl *, 4> Params;
480  QualType T = InstantiateFunctionType(D, Params);
481  if (T.isNull())
482    return 0;
483  assert(Params.size() == 0 && "Destructor with parameters?");
484
485  // Build the instantiated destructor declaration.
486  CXXRecordDecl *Record = cast<CXXRecordDecl>(Owner);
487  QualType ClassTy =
488    SemaRef.Context.getCanonicalType(SemaRef.Context.getTypeDeclType(Record));
489  CXXDestructorDecl *Destructor
490    = CXXDestructorDecl::Create(SemaRef.Context, Record,
491                                D->getLocation(),
492             SemaRef.Context.DeclarationNames.getCXXDestructorName(ClassTy),
493                                T, D->isInline(), false);
494  Destructor->setInstantiationOfMemberFunction(D);
495  if (InitMethodInstantiation(Destructor, D))
496    Destructor->setInvalidDecl();
497
498  bool Redeclaration = false;
499  bool OverloadableAttrRequired = false;
500  NamedDecl *PrevDecl = 0;
501  SemaRef.CheckFunctionDeclaration(Destructor, PrevDecl, Redeclaration,
502                                   /*FIXME:*/OverloadableAttrRequired);
503  Owner->addDecl(Destructor);
504  return Destructor;
505}
506
507Decl *TemplateDeclInstantiator::VisitCXXConversionDecl(CXXConversionDecl *D) {
508  // FIXME: Look for existing, explicit specializations.
509  Sema::LocalInstantiationScope Scope(SemaRef);
510
511  llvm::SmallVector<ParmVarDecl *, 4> Params;
512  QualType T = InstantiateFunctionType(D, Params);
513  if (T.isNull())
514    return 0;
515  assert(Params.size() == 0 && "Destructor with parameters?");
516
517  // Build the instantiated conversion declaration.
518  CXXRecordDecl *Record = cast<CXXRecordDecl>(Owner);
519  QualType ClassTy = SemaRef.Context.getTypeDeclType(Record);
520  QualType ConvTy
521    = SemaRef.Context.getCanonicalType(T->getAsFunctionType()->getResultType());
522  CXXConversionDecl *Conversion
523    = CXXConversionDecl::Create(SemaRef.Context, Record,
524                                D->getLocation(),
525         SemaRef.Context.DeclarationNames.getCXXConversionFunctionName(ConvTy),
526                                T, D->isInline(), D->isExplicit());
527  Conversion->setInstantiationOfMemberFunction(D);
528  if (InitMethodInstantiation(Conversion, D))
529    Conversion->setInvalidDecl();
530
531  bool Redeclaration = false;
532  bool OverloadableAttrRequired = false;
533  NamedDecl *PrevDecl = 0;
534  SemaRef.CheckFunctionDeclaration(Conversion, PrevDecl, Redeclaration,
535                                   /*FIXME:*/OverloadableAttrRequired);
536  Owner->addDecl(Conversion);
537  return Conversion;
538}
539
540ParmVarDecl *TemplateDeclInstantiator::VisitParmVarDecl(ParmVarDecl *D) {
541  QualType OrigT = SemaRef.InstantiateType(D->getOriginalType(), TemplateArgs,
542                                           D->getLocation(), D->getDeclName());
543  if (OrigT.isNull())
544    return 0;
545
546  QualType T = SemaRef.adjustParameterType(OrigT);
547
548  if (D->getDefaultArg()) {
549    // FIXME: Leave a marker for "uninstantiated" default
550    // arguments. They only get instantiated on demand at the call
551    // site.
552    unsigned DiagID = SemaRef.Diags.getCustomDiagID(Diagnostic::Warning,
553        "sorry, dropping default argument during template instantiation");
554    SemaRef.Diag(D->getDefaultArg()->getSourceRange().getBegin(), DiagID)
555      << D->getDefaultArg()->getSourceRange();
556  }
557
558  // Allocate the parameter
559  ParmVarDecl *Param = 0;
560  if (T == OrigT)
561    Param = ParmVarDecl::Create(SemaRef.Context, Owner, D->getLocation(),
562                                D->getIdentifier(), T, D->getStorageClass(),
563                                0);
564  else
565    Param = OriginalParmVarDecl::Create(SemaRef.Context, Owner,
566                                        D->getLocation(), D->getIdentifier(),
567                                        T, OrigT, D->getStorageClass(), 0);
568
569  // Note: we don't try to instantiate function parameters until after
570  // we've instantiated the function's type. Therefore, we don't have
571  // to check for 'void' parameter types here.
572  SemaRef.CurrentInstantiationScope->InstantiatedLocal(D, Param);
573  return Param;
574}
575
576Decl *
577TemplateDeclInstantiator::VisitOriginalParmVarDecl(OriginalParmVarDecl *D) {
578  // Since parameter types can decay either before or after
579  // instantiation, we simply treat OriginalParmVarDecls as
580  // ParmVarDecls the same way, and create one or the other depending
581  // on what happens after template instantiation.
582  return VisitParmVarDecl(D);
583}
584
585Decl *Sema::InstantiateDecl(Decl *D, DeclContext *Owner,
586                            const TemplateArgumentList &TemplateArgs) {
587  TemplateDeclInstantiator Instantiator(*this, Owner, TemplateArgs);
588  return Instantiator.Visit(D);
589}
590
591/// \brief Instantiates the type of the given function, including
592/// instantiating all of the function parameters.
593///
594/// \param D The function that we will be instantiated
595///
596/// \param Params the instantiated parameter declarations
597
598/// \returns the instantiated function's type if successfull, a NULL
599/// type if there was an error.
600QualType
601TemplateDeclInstantiator::InstantiateFunctionType(FunctionDecl *D,
602                              llvm::SmallVectorImpl<ParmVarDecl *> &Params) {
603  bool InvalidDecl = false;
604
605  // Instantiate the function parameters
606  TemplateDeclInstantiator ParamInstantiator(SemaRef, 0, TemplateArgs);
607  llvm::SmallVector<QualType, 4> ParamTys;
608  for (FunctionDecl::param_iterator P = D->param_begin(),
609                                 PEnd = D->param_end();
610       P != PEnd; ++P) {
611    if (ParmVarDecl *PInst = ParamInstantiator.VisitParmVarDecl(*P)) {
612      if (PInst->getType()->isVoidType()) {
613        SemaRef.Diag(PInst->getLocation(), diag::err_param_with_void_type);
614        PInst->setInvalidDecl();
615      } else if (SemaRef.RequireNonAbstractType(PInst->getLocation(),
616                                                PInst->getType(),
617                                                diag::err_abstract_type_in_decl,
618                                                Sema::AbstractParamType))
619        PInst->setInvalidDecl();
620
621      Params.push_back(PInst);
622      ParamTys.push_back(PInst->getType());
623
624      if (PInst->isInvalidDecl())
625        InvalidDecl = true;
626    } else
627      InvalidDecl = true;
628  }
629
630  // FIXME: Deallocate dead declarations.
631  if (InvalidDecl)
632    return QualType();
633
634  const FunctionProtoType *Proto = D->getType()->getAsFunctionProtoType();
635  assert(Proto && "Missing prototype?");
636  QualType ResultType
637    = SemaRef.InstantiateType(Proto->getResultType(), TemplateArgs,
638                              D->getLocation(), D->getDeclName());
639  if (ResultType.isNull())
640    return QualType();
641
642  return SemaRef.BuildFunctionType(ResultType, ParamTys.data(), ParamTys.size(),
643                                   Proto->isVariadic(), Proto->getTypeQuals(),
644                                   D->getLocation(), D->getDeclName());
645}
646
647/// \brief Initializes the common fields of an instantiation function
648/// declaration (New) from the corresponding fields of its template (Tmpl).
649///
650/// \returns true if there was an error
651bool
652TemplateDeclInstantiator::InitFunctionInstantiation(FunctionDecl *New,
653                                                    FunctionDecl *Tmpl) {
654  if (Tmpl->isDeleted())
655    New->setDeleted();
656
657  // If we are performing substituting explicitly-specified template arguments
658  // or deduced template arguments into a function template and we reach this
659  // point, we are now past the point where SFINAE applies and have committed
660  // to keeping the new function template specialization. We therefore
661  // convert the active template instantiation for the function template
662  // into a template instantiation for this specific function template
663  // specialization, which is not a SFINAE context, so that we diagnose any
664  // further errors in the declaration itself.
665  typedef Sema::ActiveTemplateInstantiation ActiveInstType;
666  ActiveInstType &ActiveInst = SemaRef.ActiveTemplateInstantiations.back();
667  if (ActiveInst.Kind == ActiveInstType::ExplicitTemplateArgumentSubstitution ||
668      ActiveInst.Kind == ActiveInstType::DeducedTemplateArgumentSubstitution) {
669    if (FunctionTemplateDecl *FunTmpl
670          = dyn_cast<FunctionTemplateDecl>((Decl *)ActiveInst.Entity)) {
671      assert(FunTmpl->getTemplatedDecl() == Tmpl &&
672             "Deduction from the wrong function template?");
673      (void) FunTmpl;
674      ActiveInst.Kind = ActiveInstType::TemplateInstantiation;
675      ActiveInst.Entity = reinterpret_cast<uintptr_t>(New);
676    }
677  }
678
679  return false;
680}
681
682/// \brief Initializes common fields of an instantiated method
683/// declaration (New) from the corresponding fields of its template
684/// (Tmpl).
685///
686/// \returns true if there was an error
687bool
688TemplateDeclInstantiator::InitMethodInstantiation(CXXMethodDecl *New,
689                                                  CXXMethodDecl *Tmpl) {
690  if (InitFunctionInstantiation(New, Tmpl))
691    return true;
692
693  CXXRecordDecl *Record = cast<CXXRecordDecl>(Owner);
694  New->setAccess(Tmpl->getAccess());
695  if (Tmpl->isVirtualAsWritten()) {
696    New->setVirtualAsWritten(true);
697    Record->setAggregate(false);
698    Record->setPOD(false);
699    Record->setPolymorphic(true);
700  }
701  if (Tmpl->isPure()) {
702    New->setPure();
703    Record->setAbstract(true);
704  }
705
706  // FIXME: attributes
707  // FIXME: New needs a pointer to Tmpl
708  return false;
709}
710
711/// \brief Instantiate the definition of the given function from its
712/// template.
713///
714/// \param PointOfInstantiation the point at which the instantiation was
715/// required. Note that this is not precisely a "point of instantiation"
716/// for the function, but it's close.
717///
718/// \param Function the already-instantiated declaration of a
719/// function template specialization or member function of a class template
720/// specialization.
721///
722/// \param Recursive if true, recursively instantiates any functions that
723/// are required by this instantiation.
724void Sema::InstantiateFunctionDefinition(SourceLocation PointOfInstantiation,
725                                         FunctionDecl *Function,
726                                         bool Recursive) {
727  if (Function->isInvalidDecl())
728    return;
729
730  assert(!Function->getBody() && "Already instantiated!");
731
732  // Find the function body that we'll be substituting.
733  const FunctionDecl *PatternDecl = 0;
734  if (FunctionTemplateDecl *Primary = Function->getPrimaryTemplate())
735    PatternDecl = Primary->getTemplatedDecl();
736  else
737    PatternDecl = Function->getInstantiatedFromMemberFunction();
738  Stmt *Pattern = 0;
739  if (PatternDecl)
740    Pattern = PatternDecl->getBody(PatternDecl);
741
742  if (!Pattern)
743    return;
744
745  InstantiatingTemplate Inst(*this, PointOfInstantiation, Function);
746  if (Inst)
747    return;
748
749  // If we're performing recursive template instantiation, create our own
750  // queue of pending implicit instantiations that we will instantiate later,
751  // while we're still within our own instantiation context.
752  std::deque<PendingImplicitInstantiation> SavedPendingImplicitInstantiations;
753  if (Recursive)
754    PendingImplicitInstantiations.swap(SavedPendingImplicitInstantiations);
755
756  ActOnStartOfFunctionDef(0, DeclPtrTy::make(Function));
757
758  // Introduce a new scope where local variable instantiations will be
759  // recorded.
760  LocalInstantiationScope Scope(*this);
761
762  // Introduce the instantiated function parameters into the local
763  // instantiation scope.
764  for (unsigned I = 0, N = PatternDecl->getNumParams(); I != N; ++I)
765    Scope.InstantiatedLocal(PatternDecl->getParamDecl(I),
766                            Function->getParamDecl(I));
767
768  // Enter the scope of this instantiation. We don't use
769  // PushDeclContext because we don't have a scope.
770  DeclContext *PreviousContext = CurContext;
771  CurContext = Function;
772
773  // Instantiate the function body.
774  OwningStmtResult Body
775    = InstantiateStmt(Pattern, getTemplateInstantiationArgs(Function));
776
777  ActOnFinishFunctionBody(DeclPtrTy::make(Function), move(Body),
778                          /*IsInstantiation=*/true);
779
780  CurContext = PreviousContext;
781
782  DeclGroupRef DG(Function);
783  Consumer.HandleTopLevelDecl(DG);
784
785  if (Recursive) {
786    // Instantiate any pending implicit instantiations found during the
787    // instantiation of this template.
788    PerformPendingImplicitInstantiations();
789
790    // Restore the set of pending implicit instantiations.
791    PendingImplicitInstantiations.swap(SavedPendingImplicitInstantiations);
792  }
793}
794
795/// \brief Instantiate the definition of the given variable from its
796/// template.
797///
798/// \param PointOfInstantiation the point at which the instantiation was
799/// required. Note that this is not precisely a "point of instantiation"
800/// for the function, but it's close.
801///
802/// \param Var the already-instantiated declaration of a static member
803/// variable of a class template specialization.
804///
805/// \param Recursive if true, recursively instantiates any functions that
806/// are required by this instantiation.
807void Sema::InstantiateStaticDataMemberDefinition(
808                                          SourceLocation PointOfInstantiation,
809                                                 VarDecl *Var,
810                                                 bool Recursive) {
811  if (Var->isInvalidDecl())
812    return;
813
814  // Find the out-of-line definition of this static data member.
815  // FIXME: Do we have to look for specializations separately?
816  VarDecl *Def = Var->getInstantiatedFromStaticDataMember();
817  bool FoundOutOfLineDef = false;
818  assert(Def && "This data member was not instantiated from a template?");
819  assert(Def->isStaticDataMember() && "Not a static data member?");
820  for (VarDecl::redecl_iterator RD = Def->redecls_begin(),
821                             RDEnd = Def->redecls_end();
822       RD != RDEnd; ++RD) {
823    if (RD->getLexicalDeclContext()->isFileContext()) {
824      Def = *RD;
825      FoundOutOfLineDef = true;
826    }
827  }
828
829  if (!FoundOutOfLineDef) {
830    // We did not find an out-of-line definition of this static data member,
831    // so we won't perform any instantiation. Rather, we rely on the user to
832    // instantiate this definition (or provide a specialization for it) in
833    // another translation unit.
834    return;
835  }
836
837  InstantiatingTemplate Inst(*this, PointOfInstantiation, Var);
838  if (Inst)
839    return;
840
841  // If we're performing recursive template instantiation, create our own
842  // queue of pending implicit instantiations that we will instantiate later,
843  // while we're still within our own instantiation context.
844  std::deque<PendingImplicitInstantiation> SavedPendingImplicitInstantiations;
845  if (Recursive)
846    PendingImplicitInstantiations.swap(SavedPendingImplicitInstantiations);
847
848  // Enter the scope of this instantiation. We don't use
849  // PushDeclContext because we don't have a scope.
850  DeclContext *PreviousContext = CurContext;
851  CurContext = Var->getDeclContext();
852
853#if 0
854  // Instantiate the initializer of this static data member.
855  OwningExprResult Init
856    = InstantiateExpr(Def->getInit(), getTemplateInstantiationArgs(Var));
857  if (Init.isInvalid()) {
858    // If instantiation of the initializer failed, mark the declaration invalid
859    // and don't instantiate anything else that was triggered by this
860    // instantiation.
861    Var->setInvalidDecl();
862
863    // Restore the set of pending implicit instantiations.
864    PendingImplicitInstantiations.swap(SavedPendingImplicitInstantiations);
865
866    return;
867  }
868
869  // Type-check the initializer.
870  if (Init.get())
871    AddInitializerToDecl(DeclPtrTy::make(Var), move(Init),
872                         Def->hasCXXDirectInitializer());
873  else
874    ActOnUninitializedDecl(DeclPtrTy::make(Var), false);
875#else
876  Var = cast_or_null<VarDecl>(InstantiateDecl(Def, Var->getDeclContext(),
877                                          getTemplateInstantiationArgs(Var)));
878#endif
879
880  CurContext = PreviousContext;
881
882  if (Var) {
883    DeclGroupRef DG(Var);
884    Consumer.HandleTopLevelDecl(DG);
885  }
886
887  if (Recursive) {
888    // Instantiate any pending implicit instantiations found during the
889    // instantiation of this template.
890    PerformPendingImplicitInstantiations();
891
892    // Restore the set of pending implicit instantiations.
893    PendingImplicitInstantiations.swap(SavedPendingImplicitInstantiations);
894  }
895}
896
897static bool isInstantiationOf(ASTContext &Ctx, NamedDecl *D, Decl *Other) {
898  if (D->getKind() != Other->getKind())
899    return false;
900
901  if (CXXRecordDecl *Record = dyn_cast<CXXRecordDecl>(Other))
902    return Record->getInstantiatedFromMemberClass()->getCanonicalDecl()
903             == D->getCanonicalDecl();
904
905  if (FunctionDecl *Function = dyn_cast<FunctionDecl>(Other))
906    return Function->getInstantiatedFromMemberFunction()->getCanonicalDecl()
907             == D->getCanonicalDecl();
908
909  if (EnumDecl *Enum = dyn_cast<EnumDecl>(Other))
910    return Enum->getInstantiatedFromMemberEnum()->getCanonicalDecl()
911             == D->getCanonicalDecl();
912
913  if (VarDecl *Var = dyn_cast<VarDecl>(Other))
914    if (Var->isStaticDataMember())
915      return Var->getInstantiatedFromStaticDataMember()->getCanonicalDecl()
916               == D->getCanonicalDecl();
917
918  // FIXME: How can we find instantiations of anonymous unions?
919
920  return D->getDeclName() && isa<NamedDecl>(Other) &&
921    D->getDeclName() == cast<NamedDecl>(Other)->getDeclName();
922}
923
924template<typename ForwardIterator>
925static NamedDecl *findInstantiationOf(ASTContext &Ctx,
926                                      NamedDecl *D,
927                                      ForwardIterator first,
928                                      ForwardIterator last) {
929  for (; first != last; ++first)
930    if (isInstantiationOf(Ctx, D, *first))
931      return cast<NamedDecl>(*first);
932
933  return 0;
934}
935
936/// \brief Find the instantiation of the given declaration within the
937/// current instantiation.
938///
939/// This routine is intended to be used when \p D is a declaration
940/// referenced from within a template, that needs to mapped into the
941/// corresponding declaration within an instantiation. For example,
942/// given:
943///
944/// \code
945/// template<typename T>
946/// struct X {
947///   enum Kind {
948///     KnownValue = sizeof(T)
949///   };
950///
951///   bool getKind() const { return KnownValue; }
952/// };
953///
954/// template struct X<int>;
955/// \endcode
956///
957/// In the instantiation of X<int>::getKind(), we need to map the
958/// EnumConstantDecl for KnownValue (which refers to
959/// X<T>::<Kind>::KnownValue) to its instantiation
960/// (X<int>::<Kind>::KnownValue). InstantiateCurrentDeclRef() performs
961/// this mapping from within the instantiation of X<int>.
962NamedDecl * Sema::InstantiateCurrentDeclRef(NamedDecl *D) {
963  DeclContext *ParentDC = D->getDeclContext();
964  if (isa<ParmVarDecl>(D) || ParentDC->isFunctionOrMethod()) {
965    // D is a local of some kind. Look into the map of local
966    // declarations to their instantiations.
967    return cast<NamedDecl>(CurrentInstantiationScope->getInstantiationOf(D));
968  }
969
970  if (NamedDecl *ParentDecl = dyn_cast<NamedDecl>(ParentDC)) {
971    ParentDecl = InstantiateCurrentDeclRef(ParentDecl);
972    if (!ParentDecl)
973      return 0;
974
975    ParentDC = cast<DeclContext>(ParentDecl);
976  }
977
978  if (ParentDC != D->getDeclContext()) {
979    // We performed some kind of instantiation in the parent context,
980    // so now we need to look into the instantiated parent context to
981    // find the instantiation of the declaration D.
982    NamedDecl *Result = 0;
983    if (D->getDeclName()) {
984      DeclContext::lookup_result Found = ParentDC->lookup(D->getDeclName());
985      Result = findInstantiationOf(Context, D, Found.first, Found.second);
986    } else {
987      // Since we don't have a name for the entity we're looking for,
988      // our only option is to walk through all of the declarations to
989      // find that name. This will occur in a few cases:
990      //
991      //   - anonymous struct/union within a template
992      //   - unnamed class/struct/union/enum within a template
993      //
994      // FIXME: Find a better way to find these instantiations!
995      Result = findInstantiationOf(Context, D,
996                                   ParentDC->decls_begin(),
997                                   ParentDC->decls_end());
998    }
999    assert(Result && "Unable to find instantiation of declaration!");
1000    D = Result;
1001  }
1002
1003  if (CXXRecordDecl *Record = dyn_cast<CXXRecordDecl>(D))
1004    if (ClassTemplateDecl *ClassTemplate
1005          = Record->getDescribedClassTemplate()) {
1006      // When the declaration D was parsed, it referred to the current
1007      // instantiation. Therefore, look through the current context,
1008      // which contains actual instantiations, to find the
1009      // instantiation of the "current instantiation" that D refers
1010      // to. Alternatively, we could just instantiate the
1011      // injected-class-name with the current template arguments, but
1012      // such an instantiation is far more expensive.
1013      for (DeclContext *DC = CurContext; !DC->isFileContext();
1014           DC = DC->getParent()) {
1015        if (ClassTemplateSpecializationDecl *Spec
1016              = dyn_cast<ClassTemplateSpecializationDecl>(DC))
1017          if (Spec->getSpecializedTemplate()->getCanonicalDecl()
1018              == ClassTemplate->getCanonicalDecl())
1019            return Spec;
1020      }
1021
1022      assert(false &&
1023             "Unable to find declaration for the current instantiation");
1024    }
1025
1026  return D;
1027}
1028
1029/// \brief Performs template instantiation for all implicit template
1030/// instantiations we have seen until this point.
1031void Sema::PerformPendingImplicitInstantiations() {
1032  while (!PendingImplicitInstantiations.empty()) {
1033    PendingImplicitInstantiation Inst = PendingImplicitInstantiations.front();
1034    PendingImplicitInstantiations.pop_front();
1035
1036    // Instantiate function definitions
1037    if (FunctionDecl *Function = dyn_cast<FunctionDecl>(Inst.first)) {
1038      if (!Function->getBody())
1039        InstantiateFunctionDefinition(/*FIXME:*/Inst.second, Function, true);
1040      continue;
1041    }
1042
1043    // Instantiate static data member definitions.
1044    VarDecl *Var = cast<VarDecl>(Inst.first);
1045    assert(Var->isStaticDataMember() && "Not a static data member?");
1046    InstantiateStaticDataMemberDefinition(/*FIXME:*/Inst.second, Var, true);
1047  }
1048}
1049