SemaTemplateInstantiateDecl.cpp revision 9351c173cd538f7f7c28af1494ac7e68b815b0e8 
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 *VisitFriendClassDecl(FriendClassDecl *D);
48    Decl *VisitFunctionDecl(FunctionDecl *D);
49    Decl *VisitCXXRecordDecl(CXXRecordDecl *D);
50    Decl *VisitCXXMethodDecl(CXXMethodDecl *D);
51    Decl *VisitCXXConstructorDecl(CXXConstructorDecl *D);
52    Decl *VisitCXXDestructorDecl(CXXDestructorDecl *D);
53    Decl *VisitCXXConversionDecl(CXXConversionDecl *D);
54    ParmVarDecl *VisitParmVarDecl(ParmVarDecl *D);
55    Decl *VisitOriginalParmVarDecl(OriginalParmVarDecl *D);
56    Decl *VisitClassTemplateDecl(ClassTemplateDecl *D);
57    Decl *VisitTemplateTypeParmDecl(TemplateTypeParmDecl *D);
58
59    // Base case. FIXME: Remove once we can instantiate everything.
60    Decl *VisitDecl(Decl *) {
61      assert(false && "Template instantiation of unknown declaration kind!");
62      return 0;
63    }
64
65    const LangOptions &getLangOptions() {
66      return SemaRef.getLangOptions();
67    }
68
69    // Helper functions for instantiating methods.
70    QualType InstantiateFunctionType(FunctionDecl *D,
71                             llvm::SmallVectorImpl<ParmVarDecl *> &Params);
72    bool InitFunctionInstantiation(FunctionDecl *New, FunctionDecl *Tmpl);
73    bool InitMethodInstantiation(CXXMethodDecl *New, CXXMethodDecl *Tmpl);
74
75    TemplateParameterList *
76      InstantiateTemplateParams(TemplateParameterList *List);
77  };
78}
79
80Decl *
81TemplateDeclInstantiator::VisitTranslationUnitDecl(TranslationUnitDecl *D) {
82  assert(false && "Translation units cannot be instantiated");
83  return D;
84}
85
86Decl *
87TemplateDeclInstantiator::VisitNamespaceDecl(NamespaceDecl *D) {
88  assert(false && "Namespaces cannot be instantiated");
89  return D;
90}
91
92Decl *TemplateDeclInstantiator::VisitTypedefDecl(TypedefDecl *D) {
93  bool Invalid = false;
94  QualType T = D->getUnderlyingType();
95  if (T->isDependentType()) {
96    T = SemaRef.InstantiateType(T, TemplateArgs,
97                                D->getLocation(), D->getDeclName());
98    if (T.isNull()) {
99      Invalid = true;
100      T = SemaRef.Context.IntTy;
101    }
102  }
103
104  // Create the new typedef
105  TypedefDecl *Typedef
106    = TypedefDecl::Create(SemaRef.Context, Owner, D->getLocation(),
107                          D->getIdentifier(), T);
108  if (Invalid)
109    Typedef->setInvalidDecl();
110
111  Owner->addDecl(Typedef);
112
113  return Typedef;
114}
115
116Decl *TemplateDeclInstantiator::VisitVarDecl(VarDecl *D) {
117  // Instantiate the type of the declaration
118  QualType T = SemaRef.InstantiateType(D->getType(), TemplateArgs,
119                                       D->getTypeSpecStartLoc(),
120                                       D->getDeclName());
121  if (T.isNull())
122    return 0;
123
124  // Build the instantiated declaration
125  VarDecl *Var = VarDecl::Create(SemaRef.Context, Owner,
126                                 D->getLocation(), D->getIdentifier(),
127                                 T, D->getDeclaratorInfo(),
128                                 D->getStorageClass());
129  Var->setThreadSpecified(D->isThreadSpecified());
130  Var->setCXXDirectInitializer(D->hasCXXDirectInitializer());
131  Var->setDeclaredInCondition(D->isDeclaredInCondition());
132
133  // If we are instantiating a static data member defined
134  // out-of-line, the instantiation will have the same lexical
135  // context (which will be a namespace scope) as the template.
136  if (D->isOutOfLine())
137    Var->setLexicalDeclContext(D->getLexicalDeclContext());
138
139  // FIXME: In theory, we could have a previous declaration for variables that
140  // are not static data members.
141  bool Redeclaration = false;
142  SemaRef.CheckVariableDeclaration(Var, 0, Redeclaration);
143
144  if (D->isOutOfLine()) {
145    D->getLexicalDeclContext()->addDecl(Var);
146    Owner->makeDeclVisibleInContext(Var);
147  } else {
148    Owner->addDecl(Var);
149  }
150
151  if (D->getInit()) {
152    OwningExprResult Init
153      = SemaRef.InstantiateExpr(D->getInit(), TemplateArgs);
154    if (Init.isInvalid())
155      Var->setInvalidDecl();
156    else
157      SemaRef.AddInitializerToDecl(Sema::DeclPtrTy::make(Var), move(Init),
158                                   D->hasCXXDirectInitializer());
159  } else if (!Var->isStaticDataMember() || Var->isOutOfLine())
160    SemaRef.ActOnUninitializedDecl(Sema::DeclPtrTy::make(Var), false);
161
162  // Link instantiations of static data members back to the template from
163  // which they were instantiated.
164  if (Var->isStaticDataMember())
165    SemaRef.Context.setInstantiatedFromStaticDataMember(Var, D);
166
167  return Var;
168}
169
170Decl *TemplateDeclInstantiator::VisitFieldDecl(FieldDecl *D) {
171  bool Invalid = false;
172  QualType T = D->getType();
173  if (T->isDependentType())  {
174    T = SemaRef.InstantiateType(T, TemplateArgs,
175                                D->getLocation(), D->getDeclName());
176    if (!T.isNull() && T->isFunctionType()) {
177      // C++ [temp.arg.type]p3:
178      //   If a declaration acquires a function type through a type
179      //   dependent on a template-parameter and this causes a
180      //   declaration that does not use the syntactic form of a
181      //   function declarator to have function type, the program is
182      //   ill-formed.
183      SemaRef.Diag(D->getLocation(), diag::err_field_instantiates_to_function)
184        << T;
185      T = QualType();
186      Invalid = true;
187    }
188  }
189
190  Expr *BitWidth = D->getBitWidth();
191  if (Invalid)
192    BitWidth = 0;
193  else if (BitWidth) {
194    // The bit-width expression is not potentially evaluated.
195    EnterExpressionEvaluationContext Unevaluated(SemaRef, Action::Unevaluated);
196
197    OwningExprResult InstantiatedBitWidth
198      = SemaRef.InstantiateExpr(BitWidth, TemplateArgs);
199    if (InstantiatedBitWidth.isInvalid()) {
200      Invalid = true;
201      BitWidth = 0;
202    } else
203      BitWidth = InstantiatedBitWidth.takeAs<Expr>();
204  }
205
206  FieldDecl *Field = SemaRef.CheckFieldDecl(D->getDeclName(), T,
207                                            D->getDeclaratorInfo(),
208                                            cast<RecordDecl>(Owner),
209                                            D->getLocation(),
210                                            D->isMutable(),
211                                            BitWidth,
212                                            D->getTypeSpecStartLoc(),
213                                            D->getAccess(),
214                                            0);
215  if (Field) {
216    if (Invalid)
217      Field->setInvalidDecl();
218
219    Owner->addDecl(Field);
220  }
221
222  return Field;
223}
224
225Decl *TemplateDeclInstantiator::VisitFriendClassDecl(FriendClassDecl *D) {
226  QualType T = D->getFriendType();
227  if (T->isDependentType())  {
228    T = SemaRef.InstantiateType(T, TemplateArgs, D->getLocation(),
229                                DeclarationName());
230    assert(T.isNull() || getLangOptions().CPlusPlus0x || T->isRecordType());
231  }
232
233  // FIXME: the target context might be dependent.
234  DeclContext *DC = D->getDeclContext();
235  assert(DC->isFileContext());
236
237  FriendClassDecl *NewD =
238    FriendClassDecl::Create(SemaRef.Context, DC, D->getLocation(), T,
239                            D->getFriendLoc());
240  Owner->addDecl(NewD);
241  return NewD;
242}
243
244Decl *TemplateDeclInstantiator::VisitStaticAssertDecl(StaticAssertDecl *D) {
245  Expr *AssertExpr = D->getAssertExpr();
246
247  // The expression in a static assertion is not potentially evaluated.
248  EnterExpressionEvaluationContext Unevaluated(SemaRef, Action::Unevaluated);
249
250  OwningExprResult InstantiatedAssertExpr
251    = SemaRef.InstantiateExpr(AssertExpr, TemplateArgs);
252  if (InstantiatedAssertExpr.isInvalid())
253    return 0;
254
255  OwningExprResult Message(SemaRef, D->getMessage());
256  D->getMessage()->Retain();
257  Decl *StaticAssert
258    = SemaRef.ActOnStaticAssertDeclaration(D->getLocation(),
259                                           move(InstantiatedAssertExpr),
260                                           move(Message)).getAs<Decl>();
261  return StaticAssert;
262}
263
264Decl *TemplateDeclInstantiator::VisitEnumDecl(EnumDecl *D) {
265  EnumDecl *Enum = EnumDecl::Create(SemaRef.Context, Owner,
266                                    D->getLocation(), D->getIdentifier(),
267                                    D->getTagKeywordLoc(),
268                                    /*PrevDecl=*/0);
269  Enum->setInstantiationOfMemberEnum(D);
270  Enum->setAccess(D->getAccess());
271  Owner->addDecl(Enum);
272  Enum->startDefinition();
273
274  llvm::SmallVector<Sema::DeclPtrTy, 4> Enumerators;
275
276  EnumConstantDecl *LastEnumConst = 0;
277  for (EnumDecl::enumerator_iterator EC = D->enumerator_begin(),
278         ECEnd = D->enumerator_end();
279       EC != ECEnd; ++EC) {
280    // The specified value for the enumerator.
281    OwningExprResult Value = SemaRef.Owned((Expr *)0);
282    if (Expr *UninstValue = EC->getInitExpr()) {
283      // The enumerator's value expression is not potentially evaluated.
284      EnterExpressionEvaluationContext Unevaluated(SemaRef,
285                                                   Action::Unevaluated);
286
287      Value = SemaRef.InstantiateExpr(UninstValue, TemplateArgs);
288    }
289
290    // Drop the initial value and continue.
291    bool isInvalid = false;
292    if (Value.isInvalid()) {
293      Value = SemaRef.Owned((Expr *)0);
294      isInvalid = true;
295    }
296
297    EnumConstantDecl *EnumConst
298      = SemaRef.CheckEnumConstant(Enum, LastEnumConst,
299                                  EC->getLocation(), EC->getIdentifier(),
300                                  move(Value));
301
302    if (isInvalid) {
303      if (EnumConst)
304        EnumConst->setInvalidDecl();
305      Enum->setInvalidDecl();
306    }
307
308    if (EnumConst) {
309      Enum->addDecl(EnumConst);
310      Enumerators.push_back(Sema::DeclPtrTy::make(EnumConst));
311      LastEnumConst = EnumConst;
312    }
313  }
314
315  // FIXME: Fixup LBraceLoc and RBraceLoc
316  // FIXME: Empty Scope and AttributeList (required to handle attribute packed).
317  SemaRef.ActOnEnumBody(Enum->getLocation(), SourceLocation(), SourceLocation(),
318                        Sema::DeclPtrTy::make(Enum),
319                        &Enumerators[0], Enumerators.size(),
320                        0, 0);
321
322  return Enum;
323}
324
325Decl *TemplateDeclInstantiator::VisitEnumConstantDecl(EnumConstantDecl *D) {
326  assert(false && "EnumConstantDecls can only occur within EnumDecls.");
327  return 0;
328}
329
330Decl *TemplateDeclInstantiator::VisitClassTemplateDecl(ClassTemplateDecl *D) {
331  TemplateParameterList *TempParams = D->getTemplateParameters();
332  TemplateParameterList *InstParams = InstantiateTemplateParams(TempParams);
333  if (!InstParams) return NULL;
334
335  CXXRecordDecl *Pattern = D->getTemplatedDecl();
336  CXXRecordDecl *RecordInst
337    = CXXRecordDecl::Create(SemaRef.Context, Pattern->getTagKind(), Owner,
338                            Pattern->getLocation(), Pattern->getIdentifier(),
339                            Pattern->getTagKeywordLoc(), /*PrevDecl=*/ NULL);
340
341  ClassTemplateDecl *Inst
342    = ClassTemplateDecl::Create(SemaRef.Context, Owner, D->getLocation(),
343                                D->getIdentifier(), InstParams, RecordInst, 0);
344  RecordInst->setDescribedClassTemplate(Inst);
345  Inst->setAccess(D->getAccess());
346  Inst->setInstantiatedFromMemberTemplate(D);
347
348  Owner->addDecl(Inst);
349  return Inst;
350}
351
352Decl *TemplateDeclInstantiator::VisitCXXRecordDecl(CXXRecordDecl *D) {
353  CXXRecordDecl *PrevDecl = 0;
354  if (D->isInjectedClassName())
355    PrevDecl = cast<CXXRecordDecl>(Owner);
356
357  CXXRecordDecl *Record
358    = CXXRecordDecl::Create(SemaRef.Context, D->getTagKind(), Owner,
359                            D->getLocation(), D->getIdentifier(),
360                            D->getTagKeywordLoc(), PrevDecl);
361  Record->setImplicit(D->isImplicit());
362  Record->setAccess(D->getAccess());
363  if (!D->isInjectedClassName())
364    Record->setInstantiationOfMemberClass(D);
365
366  Owner->addDecl(Record);
367  return Record;
368}
369
370Decl *TemplateDeclInstantiator::VisitFunctionDecl(FunctionDecl *D) {
371  // Check whether there is already a function template specialization for
372  // this declaration.
373  FunctionTemplateDecl *FunctionTemplate = D->getDescribedFunctionTemplate();
374  void *InsertPos = 0;
375  if (FunctionTemplate) {
376    llvm::FoldingSetNodeID ID;
377    FunctionTemplateSpecializationInfo::Profile(ID,
378                                          TemplateArgs.getFlatArgumentList(),
379                                                TemplateArgs.flat_size(),
380                                                SemaRef.Context);
381
382    FunctionTemplateSpecializationInfo *Info
383      = FunctionTemplate->getSpecializations().FindNodeOrInsertPos(ID,
384                                                                   InsertPos);
385
386    // If we already have a function template specialization, return it.
387    if (Info)
388      return Info->Function;
389  }
390
391  Sema::LocalInstantiationScope Scope(SemaRef);
392
393  llvm::SmallVector<ParmVarDecl *, 4> Params;
394  QualType T = InstantiateFunctionType(D, Params);
395  if (T.isNull())
396    return 0;
397
398  // Build the instantiated method declaration.
399  FunctionDecl *Function;
400  if (FriendFunctionDecl* FFD = dyn_cast<FriendFunctionDecl>(D)) {
401    // The new decl's semantic context.  FIXME:  this might need
402    // to be instantiated.
403    DeclContext *DC = D->getDeclContext();
404
405    // This assert is bogus and exists only to catch cases we don't
406    // handle yet.
407    assert(!DC->isDependentContext());
408
409    Function =
410      FriendFunctionDecl::Create(SemaRef.Context, DC, D->getLocation(),
411                                 D->getDeclName(), T, D->getDeclaratorInfo(),
412                                 D->isInline(), FFD->getFriendLoc());
413    Function->setLexicalDeclContext(Owner);
414  } else {
415    Function =
416      FunctionDecl::Create(SemaRef.Context, Owner, D->getLocation(),
417                           D->getDeclName(), T, D->getDeclaratorInfo(),
418                           D->getStorageClass(),
419                           D->isInline(), D->hasWrittenPrototype());
420  }
421
422  // Attach the parameters
423  for (unsigned P = 0; P < Params.size(); ++P)
424    Params[P]->setOwningFunction(Function);
425  Function->setParams(SemaRef.Context, Params.data(), Params.size());
426
427  if (InitFunctionInstantiation(Function, D))
428    Function->setInvalidDecl();
429
430  bool Redeclaration = false;
431  bool OverloadableAttrRequired = false;
432  NamedDecl *PrevDecl = 0;
433  SemaRef.CheckFunctionDeclaration(Function, PrevDecl, Redeclaration,
434                                   /*FIXME:*/OverloadableAttrRequired);
435
436  if (FunctionTemplate) {
437    // Record this function template specialization.
438    Function->setFunctionTemplateSpecialization(SemaRef.Context,
439                                                FunctionTemplate,
440                                                &TemplateArgs,
441                                                InsertPos);
442  }
443
444  // If this was a friend function decl, it's a member which
445  // needs to be added.
446  if (isa<FriendFunctionDecl>(Function)) {
447    // If the new context is still dependent, this declaration
448    // needs to remain hidden.
449    if (Owner->isDependentContext())
450      Owner->addHiddenDecl(Function);
451    else
452      Owner->addDecl(Function);
453  }
454
455  return Function;
456}
457
458Decl *TemplateDeclInstantiator::VisitCXXMethodDecl(CXXMethodDecl *D) {
459  // Check whether there is already a function template specialization for
460  // this declaration.
461  FunctionTemplateDecl *FunctionTemplate = D->getDescribedFunctionTemplate();
462  void *InsertPos = 0;
463  if (FunctionTemplate) {
464    llvm::FoldingSetNodeID ID;
465    FunctionTemplateSpecializationInfo::Profile(ID,
466                                          TemplateArgs.getFlatArgumentList(),
467                                                TemplateArgs.flat_size(),
468                                                SemaRef.Context);
469
470    FunctionTemplateSpecializationInfo *Info
471      = FunctionTemplate->getSpecializations().FindNodeOrInsertPos(ID,
472                                                                   InsertPos);
473
474    // If we already have a function template specialization, return it.
475    if (Info)
476      return Info->Function;
477  }
478
479  Sema::LocalInstantiationScope Scope(SemaRef);
480
481  llvm::SmallVector<ParmVarDecl *, 4> Params;
482  QualType T = InstantiateFunctionType(D, Params);
483  if (T.isNull())
484    return 0;
485
486  // Build the instantiated method declaration.
487  CXXRecordDecl *Record = cast<CXXRecordDecl>(Owner);
488  CXXMethodDecl *Method = 0;
489
490  DeclarationName Name = D->getDeclName();
491  if (CXXConstructorDecl *Constructor = dyn_cast<CXXConstructorDecl>(D)) {
492    QualType ClassTy = SemaRef.Context.getTypeDeclType(Record);
493    Name = SemaRef.Context.DeclarationNames.getCXXConstructorName(
494                                    SemaRef.Context.getCanonicalType(ClassTy));
495    Method = CXXConstructorDecl::Create(SemaRef.Context, Record,
496                                        Constructor->getLocation(),
497                                        Name, T,
498                                        Constructor->getDeclaratorInfo(),
499                                        Constructor->isExplicit(),
500                                        Constructor->isInline(), false);
501  } else if (CXXDestructorDecl *Destructor = dyn_cast<CXXDestructorDecl>(D)) {
502    QualType ClassTy = SemaRef.Context.getTypeDeclType(Record);
503    Name = SemaRef.Context.DeclarationNames.getCXXDestructorName(
504                                   SemaRef.Context.getCanonicalType(ClassTy));
505    Method = CXXDestructorDecl::Create(SemaRef.Context, Record,
506                                       Destructor->getLocation(), Name,
507                                       T, Destructor->isInline(), false);
508  } else if (CXXConversionDecl *Conversion = dyn_cast<CXXConversionDecl>(D)) {
509    CanQualType ConvTy
510      = SemaRef.Context.getCanonicalType(
511                                      T->getAsFunctionType()->getResultType());
512    Name = SemaRef.Context.DeclarationNames.getCXXConversionFunctionName(
513                                                                      ConvTy);
514    Method = CXXConversionDecl::Create(SemaRef.Context, Record,
515                                       Conversion->getLocation(), Name,
516                                       T, Conversion->getDeclaratorInfo(),
517                                       Conversion->isInline(),
518                                       Conversion->isExplicit());
519  } else {
520    Method = CXXMethodDecl::Create(SemaRef.Context, Record, D->getLocation(),
521                                   D->getDeclName(), T, D->getDeclaratorInfo(),
522                                   D->isStatic(), D->isInline());
523  }
524
525  if (!FunctionTemplate)
526    Method->setInstantiationOfMemberFunction(D);
527
528  // If we are instantiating a member function defined
529  // out-of-line, the instantiation will have the same lexical
530  // context (which will be a namespace scope) as the template.
531  if (D->isOutOfLine())
532    Method->setLexicalDeclContext(D->getLexicalDeclContext());
533
534  // Attach the parameters
535  for (unsigned P = 0; P < Params.size(); ++P)
536    Params[P]->setOwningFunction(Method);
537  Method->setParams(SemaRef.Context, Params.data(), Params.size());
538
539  if (InitMethodInstantiation(Method, D))
540    Method->setInvalidDecl();
541
542  NamedDecl *PrevDecl = 0;
543
544  if (!FunctionTemplate) {
545    PrevDecl = SemaRef.LookupQualifiedName(Owner, Name,
546                                           Sema::LookupOrdinaryName, true);
547
548    // In C++, the previous declaration we find might be a tag type
549    // (class or enum). In this case, the new declaration will hide the
550    // tag type. Note that this does does not apply if we're declaring a
551    // typedef (C++ [dcl.typedef]p4).
552    if (PrevDecl && PrevDecl->getIdentifierNamespace() == Decl::IDNS_Tag)
553      PrevDecl = 0;
554  }
555
556  if (FunctionTemplate)
557    // Record this function template specialization.
558    Method->setFunctionTemplateSpecialization(SemaRef.Context,
559                                              FunctionTemplate,
560                                              &TemplateArgs,
561                                              InsertPos);
562
563  bool Redeclaration = false;
564  bool OverloadableAttrRequired = false;
565  SemaRef.CheckFunctionDeclaration(Method, PrevDecl, Redeclaration,
566                                   /*FIXME:*/OverloadableAttrRequired);
567
568  if (!FunctionTemplate && (!Method->isInvalidDecl() || !PrevDecl))
569    Owner->addDecl(Method);
570
571  return Method;
572}
573
574Decl *TemplateDeclInstantiator::VisitCXXConstructorDecl(CXXConstructorDecl *D) {
575  return VisitCXXMethodDecl(D);
576}
577
578Decl *TemplateDeclInstantiator::VisitCXXDestructorDecl(CXXDestructorDecl *D) {
579  return VisitCXXMethodDecl(D);
580}
581
582Decl *TemplateDeclInstantiator::VisitCXXConversionDecl(CXXConversionDecl *D) {
583  return VisitCXXMethodDecl(D);
584}
585
586ParmVarDecl *TemplateDeclInstantiator::VisitParmVarDecl(ParmVarDecl *D) {
587  QualType OrigT = SemaRef.InstantiateType(D->getOriginalType(), TemplateArgs,
588                                           D->getLocation(), D->getDeclName());
589  if (OrigT.isNull())
590    return 0;
591
592  QualType T = SemaRef.adjustParameterType(OrigT);
593
594  // Allocate the parameter
595  ParmVarDecl *Param = 0;
596  if (T == OrigT)
597    Param = ParmVarDecl::Create(SemaRef.Context, Owner, D->getLocation(),
598                                D->getIdentifier(), T, D->getDeclaratorInfo(),
599                                D->getStorageClass(), 0);
600  else
601    Param = OriginalParmVarDecl::Create(SemaRef.Context, Owner,
602                                        D->getLocation(), D->getIdentifier(),
603                                        T, D->getDeclaratorInfo(), OrigT,
604                                        D->getStorageClass(), 0);
605
606  // Mark the default argument as being uninstantiated.
607  if (Expr *Arg = D->getDefaultArg())
608    Param->setUninstantiatedDefaultArg(Arg);
609
610  // Note: we don't try to instantiate function parameters until after
611  // we've instantiated the function's type. Therefore, we don't have
612  // to check for 'void' parameter types here.
613  SemaRef.CurrentInstantiationScope->InstantiatedLocal(D, Param);
614  return Param;
615}
616
617Decl *
618TemplateDeclInstantiator::VisitOriginalParmVarDecl(OriginalParmVarDecl *D) {
619  // Since parameter types can decay either before or after
620  // instantiation, we simply treat OriginalParmVarDecls as
621  // ParmVarDecls the same way, and create one or the other depending
622  // on what happens after template instantiation.
623  return VisitParmVarDecl(D);
624}
625
626Decl *TemplateDeclInstantiator::VisitTemplateTypeParmDecl(
627                                                    TemplateTypeParmDecl *D) {
628  // TODO: don't always clone when decls are refcounted.
629  const Type* T = D->getTypeForDecl();
630  assert(T->isTemplateTypeParmType());
631  const TemplateTypeParmType *TTPT = T->getAs<TemplateTypeParmType>();
632
633  TemplateTypeParmDecl *Inst =
634    TemplateTypeParmDecl::Create(SemaRef.Context, Owner, D->getLocation(),
635                                 TTPT->getDepth(), TTPT->getIndex(),
636                                 TTPT->getName(),
637                                 D->wasDeclaredWithTypename(),
638                                 D->isParameterPack());
639
640  if (D->hasDefaultArgument()) {
641    QualType DefaultPattern = D->getDefaultArgument();
642    QualType DefaultInst
643      = SemaRef.InstantiateType(DefaultPattern, TemplateArgs,
644                                D->getDefaultArgumentLoc(),
645                                D->getDeclName());
646
647    Inst->setDefaultArgument(DefaultInst,
648                             D->getDefaultArgumentLoc(),
649                             D->defaultArgumentWasInherited() /* preserve? */);
650  }
651
652  return Inst;
653}
654
655Decl *Sema::InstantiateDecl(Decl *D, DeclContext *Owner,
656                            const TemplateArgumentList &TemplateArgs) {
657  TemplateDeclInstantiator Instantiator(*this, Owner, TemplateArgs);
658  return Instantiator.Visit(D);
659}
660
661/// \brief Instantiates a nested template parameter list in the current
662/// instantiation context.
663///
664/// \param L The parameter list to instantiate
665///
666/// \returns NULL if there was an error
667TemplateParameterList *
668TemplateDeclInstantiator::InstantiateTemplateParams(TemplateParameterList *L) {
669  // Get errors for all the parameters before bailing out.
670  bool Invalid = false;
671
672  unsigned N = L->size();
673  typedef llvm::SmallVector<Decl*,8> ParamVector;
674  ParamVector Params;
675  Params.reserve(N);
676  for (TemplateParameterList::iterator PI = L->begin(), PE = L->end();
677       PI != PE; ++PI) {
678    Decl *D = Visit(*PI);
679    Params.push_back(D);
680    Invalid = Invalid || !D;
681  }
682
683  // Clean up if we had an error.
684  if (Invalid) {
685    for (ParamVector::iterator PI = Params.begin(), PE = Params.end();
686         PI != PE; ++PI)
687      if (*PI)
688        (*PI)->Destroy(SemaRef.Context);
689    return NULL;
690  }
691
692  TemplateParameterList *InstL
693    = TemplateParameterList::Create(SemaRef.Context, L->getTemplateLoc(),
694                                    L->getLAngleLoc(), &Params.front(), N,
695                                    L->getRAngleLoc());
696  return InstL;
697}
698
699/// \brief Instantiates the type of the given function, including
700/// instantiating all of the function parameters.
701///
702/// \param D The function that we will be instantiated
703///
704/// \param Params the instantiated parameter declarations
705
706/// \returns the instantiated function's type if successfull, a NULL
707/// type if there was an error.
708QualType
709TemplateDeclInstantiator::InstantiateFunctionType(FunctionDecl *D,
710                              llvm::SmallVectorImpl<ParmVarDecl *> &Params) {
711  bool InvalidDecl = false;
712
713  // Instantiate the function parameters
714  TemplateDeclInstantiator ParamInstantiator(SemaRef, 0, TemplateArgs);
715  llvm::SmallVector<QualType, 4> ParamTys;
716  for (FunctionDecl::param_iterator P = D->param_begin(),
717                                 PEnd = D->param_end();
718       P != PEnd; ++P) {
719    if (ParmVarDecl *PInst = ParamInstantiator.VisitParmVarDecl(*P)) {
720      if (PInst->getType()->isVoidType()) {
721        SemaRef.Diag(PInst->getLocation(), diag::err_param_with_void_type);
722        PInst->setInvalidDecl();
723      } else if (SemaRef.RequireNonAbstractType(PInst->getLocation(),
724                                                PInst->getType(),
725                                                diag::err_abstract_type_in_decl,
726                                                Sema::AbstractParamType))
727        PInst->setInvalidDecl();
728
729      Params.push_back(PInst);
730      ParamTys.push_back(PInst->getType());
731
732      if (PInst->isInvalidDecl())
733        InvalidDecl = true;
734    } else
735      InvalidDecl = true;
736  }
737
738  // FIXME: Deallocate dead declarations.
739  if (InvalidDecl)
740    return QualType();
741
742  const FunctionProtoType *Proto = D->getType()->getAsFunctionProtoType();
743  assert(Proto && "Missing prototype?");
744  QualType ResultType
745    = SemaRef.InstantiateType(Proto->getResultType(), TemplateArgs,
746                              D->getLocation(), D->getDeclName());
747  if (ResultType.isNull())
748    return QualType();
749
750  return SemaRef.BuildFunctionType(ResultType, ParamTys.data(), ParamTys.size(),
751                                   Proto->isVariadic(), Proto->getTypeQuals(),
752                                   D->getLocation(), D->getDeclName());
753}
754
755/// \brief Initializes the common fields of an instantiation function
756/// declaration (New) from the corresponding fields of its template (Tmpl).
757///
758/// \returns true if there was an error
759bool
760TemplateDeclInstantiator::InitFunctionInstantiation(FunctionDecl *New,
761                                                    FunctionDecl *Tmpl) {
762  if (Tmpl->isDeleted())
763    New->setDeleted();
764
765  // If we are performing substituting explicitly-specified template arguments
766  // or deduced template arguments into a function template and we reach this
767  // point, we are now past the point where SFINAE applies and have committed
768  // to keeping the new function template specialization. We therefore
769  // convert the active template instantiation for the function template
770  // into a template instantiation for this specific function template
771  // specialization, which is not a SFINAE context, so that we diagnose any
772  // further errors in the declaration itself.
773  typedef Sema::ActiveTemplateInstantiation ActiveInstType;
774  ActiveInstType &ActiveInst = SemaRef.ActiveTemplateInstantiations.back();
775  if (ActiveInst.Kind == ActiveInstType::ExplicitTemplateArgumentSubstitution ||
776      ActiveInst.Kind == ActiveInstType::DeducedTemplateArgumentSubstitution) {
777    if (FunctionTemplateDecl *FunTmpl
778          = dyn_cast<FunctionTemplateDecl>((Decl *)ActiveInst.Entity)) {
779      assert(FunTmpl->getTemplatedDecl() == Tmpl &&
780             "Deduction from the wrong function template?");
781      (void) FunTmpl;
782      ActiveInst.Kind = ActiveInstType::TemplateInstantiation;
783      ActiveInst.Entity = reinterpret_cast<uintptr_t>(New);
784    }
785  }
786
787  return false;
788}
789
790/// \brief Initializes common fields of an instantiated method
791/// declaration (New) from the corresponding fields of its template
792/// (Tmpl).
793///
794/// \returns true if there was an error
795bool
796TemplateDeclInstantiator::InitMethodInstantiation(CXXMethodDecl *New,
797                                                  CXXMethodDecl *Tmpl) {
798  if (InitFunctionInstantiation(New, Tmpl))
799    return true;
800
801  CXXRecordDecl *Record = cast<CXXRecordDecl>(Owner);
802  New->setAccess(Tmpl->getAccess());
803  if (Tmpl->isVirtualAsWritten()) {
804    New->setVirtualAsWritten(true);
805    Record->setAggregate(false);
806    Record->setPOD(false);
807    Record->setEmpty(false);
808    Record->setPolymorphic(true);
809  }
810  if (Tmpl->isPure()) {
811    New->setPure();
812    Record->setAbstract(true);
813  }
814
815  // FIXME: attributes
816  // FIXME: New needs a pointer to Tmpl
817  return false;
818}
819
820/// \brief Instantiate the definition of the given function from its
821/// template.
822///
823/// \param PointOfInstantiation the point at which the instantiation was
824/// required. Note that this is not precisely a "point of instantiation"
825/// for the function, but it's close.
826///
827/// \param Function the already-instantiated declaration of a
828/// function template specialization or member function of a class template
829/// specialization.
830///
831/// \param Recursive if true, recursively instantiates any functions that
832/// are required by this instantiation.
833void Sema::InstantiateFunctionDefinition(SourceLocation PointOfInstantiation,
834                                         FunctionDecl *Function,
835                                         bool Recursive) {
836  if (Function->isInvalidDecl())
837    return;
838
839  assert(!Function->getBody() && "Already instantiated!");
840
841  // Find the function body that we'll be substituting.
842  const FunctionDecl *PatternDecl = 0;
843  if (FunctionTemplateDecl *Primary = Function->getPrimaryTemplate())
844    PatternDecl = Primary->getTemplatedDecl();
845  else
846    PatternDecl = Function->getInstantiatedFromMemberFunction();
847  Stmt *Pattern = 0;
848  if (PatternDecl)
849    Pattern = PatternDecl->getBody(PatternDecl);
850
851  if (!Pattern)
852    return;
853
854  InstantiatingTemplate Inst(*this, PointOfInstantiation, Function);
855  if (Inst)
856    return;
857
858  // If we're performing recursive template instantiation, create our own
859  // queue of pending implicit instantiations that we will instantiate later,
860  // while we're still within our own instantiation context.
861  std::deque<PendingImplicitInstantiation> SavedPendingImplicitInstantiations;
862  if (Recursive)
863    PendingImplicitInstantiations.swap(SavedPendingImplicitInstantiations);
864
865  ActOnStartOfFunctionDef(0, DeclPtrTy::make(Function));
866
867  // Introduce a new scope where local variable instantiations will be
868  // recorded.
869  LocalInstantiationScope Scope(*this);
870
871  // Introduce the instantiated function parameters into the local
872  // instantiation scope.
873  for (unsigned I = 0, N = PatternDecl->getNumParams(); I != N; ++I)
874    Scope.InstantiatedLocal(PatternDecl->getParamDecl(I),
875                            Function->getParamDecl(I));
876
877  // Enter the scope of this instantiation. We don't use
878  // PushDeclContext because we don't have a scope.
879  DeclContext *PreviousContext = CurContext;
880  CurContext = Function;
881
882  // Instantiate the function body.
883  OwningStmtResult Body
884    = InstantiateStmt(Pattern, getTemplateInstantiationArgs(Function));
885
886  ActOnFinishFunctionBody(DeclPtrTy::make(Function), move(Body),
887                          /*IsInstantiation=*/true);
888
889  CurContext = PreviousContext;
890
891  DeclGroupRef DG(Function);
892  Consumer.HandleTopLevelDecl(DG);
893
894  if (Recursive) {
895    // Instantiate any pending implicit instantiations found during the
896    // instantiation of this template.
897    PerformPendingImplicitInstantiations();
898
899    // Restore the set of pending implicit instantiations.
900    PendingImplicitInstantiations.swap(SavedPendingImplicitInstantiations);
901  }
902}
903
904/// \brief Instantiate the definition of the given variable from its
905/// template.
906///
907/// \param PointOfInstantiation the point at which the instantiation was
908/// required. Note that this is not precisely a "point of instantiation"
909/// for the function, but it's close.
910///
911/// \param Var the already-instantiated declaration of a static member
912/// variable of a class template specialization.
913///
914/// \param Recursive if true, recursively instantiates any functions that
915/// are required by this instantiation.
916void Sema::InstantiateStaticDataMemberDefinition(
917                                          SourceLocation PointOfInstantiation,
918                                                 VarDecl *Var,
919                                                 bool Recursive) {
920  if (Var->isInvalidDecl())
921    return;
922
923  // Find the out-of-line definition of this static data member.
924  // FIXME: Do we have to look for specializations separately?
925  VarDecl *Def = Var->getInstantiatedFromStaticDataMember();
926  bool FoundOutOfLineDef = false;
927  assert(Def && "This data member was not instantiated from a template?");
928  assert(Def->isStaticDataMember() && "Not a static data member?");
929  for (VarDecl::redecl_iterator RD = Def->redecls_begin(),
930                             RDEnd = Def->redecls_end();
931       RD != RDEnd; ++RD) {
932    if (RD->getLexicalDeclContext()->isFileContext()) {
933      Def = *RD;
934      FoundOutOfLineDef = true;
935    }
936  }
937
938  if (!FoundOutOfLineDef) {
939    // We did not find an out-of-line definition of this static data member,
940    // so we won't perform any instantiation. Rather, we rely on the user to
941    // instantiate this definition (or provide a specialization for it) in
942    // another translation unit.
943    return;
944  }
945
946  InstantiatingTemplate Inst(*this, PointOfInstantiation, Var);
947  if (Inst)
948    return;
949
950  // If we're performing recursive template instantiation, create our own
951  // queue of pending implicit instantiations that we will instantiate later,
952  // while we're still within our own instantiation context.
953  std::deque<PendingImplicitInstantiation> SavedPendingImplicitInstantiations;
954  if (Recursive)
955    PendingImplicitInstantiations.swap(SavedPendingImplicitInstantiations);
956
957  // Enter the scope of this instantiation. We don't use
958  // PushDeclContext because we don't have a scope.
959  DeclContext *PreviousContext = CurContext;
960  CurContext = Var->getDeclContext();
961
962#if 0
963  // Instantiate the initializer of this static data member.
964  OwningExprResult Init
965    = InstantiateExpr(Def->getInit(), getTemplateInstantiationArgs(Var));
966  if (Init.isInvalid()) {
967    // If instantiation of the initializer failed, mark the declaration invalid
968    // and don't instantiate anything else that was triggered by this
969    // instantiation.
970    Var->setInvalidDecl();
971
972    // Restore the set of pending implicit instantiations.
973    PendingImplicitInstantiations.swap(SavedPendingImplicitInstantiations);
974
975    return;
976  }
977
978  // Type-check the initializer.
979  if (Init.get())
980    AddInitializerToDecl(DeclPtrTy::make(Var), move(Init),
981                         Def->hasCXXDirectInitializer());
982  else
983    ActOnUninitializedDecl(DeclPtrTy::make(Var), false);
984#else
985  Var = cast_or_null<VarDecl>(InstantiateDecl(Def, Var->getDeclContext(),
986                                          getTemplateInstantiationArgs(Var)));
987#endif
988
989  CurContext = PreviousContext;
990
991  if (Var) {
992    DeclGroupRef DG(Var);
993    Consumer.HandleTopLevelDecl(DG);
994  }
995
996  if (Recursive) {
997    // Instantiate any pending implicit instantiations found during the
998    // instantiation of this template.
999    PerformPendingImplicitInstantiations();
1000
1001    // Restore the set of pending implicit instantiations.
1002    PendingImplicitInstantiations.swap(SavedPendingImplicitInstantiations);
1003  }
1004}
1005
1006static bool isInstantiationOf(ASTContext &Ctx, NamedDecl *D, Decl *Other) {
1007  if (D->getKind() != Other->getKind())
1008    return false;
1009
1010  if (CXXRecordDecl *Record = dyn_cast<CXXRecordDecl>(Other))
1011    return Record->getInstantiatedFromMemberClass()->getCanonicalDecl()
1012             == D->getCanonicalDecl();
1013
1014  if (FunctionDecl *Function = dyn_cast<FunctionDecl>(Other))
1015    return Function->getInstantiatedFromMemberFunction()->getCanonicalDecl()
1016             == D->getCanonicalDecl();
1017
1018  if (EnumDecl *Enum = dyn_cast<EnumDecl>(Other))
1019    return Enum->getInstantiatedFromMemberEnum()->getCanonicalDecl()
1020             == D->getCanonicalDecl();
1021
1022  if (VarDecl *Var = dyn_cast<VarDecl>(Other))
1023    if (Var->isStaticDataMember())
1024      return Var->getInstantiatedFromStaticDataMember()->getCanonicalDecl()
1025               == D->getCanonicalDecl();
1026
1027  // FIXME: How can we find instantiations of anonymous unions?
1028
1029  return D->getDeclName() && isa<NamedDecl>(Other) &&
1030    D->getDeclName() == cast<NamedDecl>(Other)->getDeclName();
1031}
1032
1033template<typename ForwardIterator>
1034static NamedDecl *findInstantiationOf(ASTContext &Ctx,
1035                                      NamedDecl *D,
1036                                      ForwardIterator first,
1037                                      ForwardIterator last) {
1038  for (; first != last; ++first)
1039    if (isInstantiationOf(Ctx, D, *first))
1040      return cast<NamedDecl>(*first);
1041
1042  return 0;
1043}
1044
1045/// \brief Find the instantiation of the given declaration within the
1046/// current instantiation.
1047///
1048/// This routine is intended to be used when \p D is a declaration
1049/// referenced from within a template, that needs to mapped into the
1050/// corresponding declaration within an instantiation. For example,
1051/// given:
1052///
1053/// \code
1054/// template<typename T>
1055/// struct X {
1056///   enum Kind {
1057///     KnownValue = sizeof(T)
1058///   };
1059///
1060///   bool getKind() const { return KnownValue; }
1061/// };
1062///
1063/// template struct X<int>;
1064/// \endcode
1065///
1066/// In the instantiation of X<int>::getKind(), we need to map the
1067/// EnumConstantDecl for KnownValue (which refers to
1068/// X<T>::<Kind>::KnownValue) to its instantiation
1069/// (X<int>::<Kind>::KnownValue). InstantiateCurrentDeclRef() performs
1070/// this mapping from within the instantiation of X<int>.
1071NamedDecl * Sema::InstantiateCurrentDeclRef(NamedDecl *D) {
1072  DeclContext *ParentDC = D->getDeclContext();
1073  if (isa<ParmVarDecl>(D) || ParentDC->isFunctionOrMethod()) {
1074    // D is a local of some kind. Look into the map of local
1075    // declarations to their instantiations.
1076    return cast<NamedDecl>(CurrentInstantiationScope->getInstantiationOf(D));
1077  }
1078
1079  if (NamedDecl *ParentDecl = dyn_cast<NamedDecl>(ParentDC)) {
1080    ParentDecl = InstantiateCurrentDeclRef(ParentDecl);
1081    if (!ParentDecl)
1082      return 0;
1083
1084    ParentDC = cast<DeclContext>(ParentDecl);
1085  }
1086
1087  if (ParentDC != D->getDeclContext()) {
1088    // We performed some kind of instantiation in the parent context,
1089    // so now we need to look into the instantiated parent context to
1090    // find the instantiation of the declaration D.
1091    NamedDecl *Result = 0;
1092    if (D->getDeclName()) {
1093      DeclContext::lookup_result Found = ParentDC->lookup(D->getDeclName());
1094      Result = findInstantiationOf(Context, D, Found.first, Found.second);
1095    } else {
1096      // Since we don't have a name for the entity we're looking for,
1097      // our only option is to walk through all of the declarations to
1098      // find that name. This will occur in a few cases:
1099      //
1100      //   - anonymous struct/union within a template
1101      //   - unnamed class/struct/union/enum within a template
1102      //
1103      // FIXME: Find a better way to find these instantiations!
1104      Result = findInstantiationOf(Context, D,
1105                                   ParentDC->decls_begin(),
1106                                   ParentDC->decls_end());
1107    }
1108    assert(Result && "Unable to find instantiation of declaration!");
1109    D = Result;
1110  }
1111
1112  if (CXXRecordDecl *Record = dyn_cast<CXXRecordDecl>(D))
1113    if (ClassTemplateDecl *ClassTemplate
1114          = Record->getDescribedClassTemplate()) {
1115      // When the declaration D was parsed, it referred to the current
1116      // instantiation. Therefore, look through the current context,
1117      // which contains actual instantiations, to find the
1118      // instantiation of the "current instantiation" that D refers
1119      // to. Alternatively, we could just instantiate the
1120      // injected-class-name with the current template arguments, but
1121      // such an instantiation is far more expensive.
1122      for (DeclContext *DC = CurContext; !DC->isFileContext();
1123           DC = DC->getParent()) {
1124        if (ClassTemplateSpecializationDecl *Spec
1125              = dyn_cast<ClassTemplateSpecializationDecl>(DC))
1126          if (Spec->getSpecializedTemplate()->getCanonicalDecl()
1127              == ClassTemplate->getCanonicalDecl())
1128            return Spec;
1129      }
1130
1131      assert(false &&
1132             "Unable to find declaration for the current instantiation");
1133    }
1134
1135  return D;
1136}
1137
1138/// \brief Performs template instantiation for all implicit template
1139/// instantiations we have seen until this point.
1140void Sema::PerformPendingImplicitInstantiations() {
1141  while (!PendingImplicitInstantiations.empty()) {
1142    PendingImplicitInstantiation Inst = PendingImplicitInstantiations.front();
1143    PendingImplicitInstantiations.pop_front();
1144
1145    // Instantiate function definitions
1146    if (FunctionDecl *Function = dyn_cast<FunctionDecl>(Inst.first)) {
1147      if (!Function->getBody())
1148        InstantiateFunctionDefinition(/*FIXME:*/Inst.second, Function, true);
1149      continue;
1150    }
1151
1152    // Instantiate static data member definitions.
1153    VarDecl *Var = cast<VarDecl>(Inst.first);
1154    assert(Var->isStaticDataMember() && "Not a static data member?");
1155    InstantiateStaticDataMemberDefinition(/*FIXME:*/Inst.second, Var, true);
1156  }
1157}
1158