SemaTemplateInstantiate.cpp revision 124b878dba5007df0a268ea128a6ad8dc5dd2c5e 
1//===------- SemaTemplateInstantiate.cpp - C++ Template 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.
10//
11//===----------------------------------------------------------------------===/
12
13#include "Sema.h"
14#include "TreeTransform.h"
15#include "Lookup.h"
16#include "clang/AST/ASTConsumer.h"
17#include "clang/AST/ASTContext.h"
18#include "clang/AST/Expr.h"
19#include "clang/AST/DeclTemplate.h"
20#include "clang/Parse/DeclSpec.h"
21#include "clang/Basic/LangOptions.h"
22
23using namespace clang;
24
25//===----------------------------------------------------------------------===/
26// Template Instantiation Support
27//===----------------------------------------------------------------------===/
28
29/// \brief Retrieve the template argument list(s) that should be used to
30/// instantiate the definition of the given declaration.
31///
32/// \param D the declaration for which we are computing template instantiation
33/// arguments.
34///
35/// \param Innermost if non-NULL, the innermost template argument list.
36///
37/// \param RelativeToPrimary true if we should get the template
38/// arguments relative to the primary template, even when we're
39/// dealing with a specialization. This is only relevant for function
40/// template specializations.
41MultiLevelTemplateArgumentList
42Sema::getTemplateInstantiationArgs(NamedDecl *D,
43                                   const TemplateArgumentList *Innermost,
44                                   bool RelativeToPrimary) {
45  // Accumulate the set of template argument lists in this structure.
46  MultiLevelTemplateArgumentList Result;
47
48  if (Innermost)
49    Result.addOuterTemplateArguments(Innermost);
50
51  DeclContext *Ctx = dyn_cast<DeclContext>(D);
52  if (!Ctx)
53    Ctx = D->getDeclContext();
54
55  while (!Ctx->isFileContext()) {
56    // Add template arguments from a class template instantiation.
57    if (ClassTemplateSpecializationDecl *Spec
58          = dyn_cast<ClassTemplateSpecializationDecl>(Ctx)) {
59      // We're done when we hit an explicit specialization.
60      if (Spec->getSpecializationKind() == TSK_ExplicitSpecialization)
61        break;
62
63      Result.addOuterTemplateArguments(&Spec->getTemplateInstantiationArgs());
64
65      // If this class template specialization was instantiated from a
66      // specialized member that is a class template, we're done.
67      assert(Spec->getSpecializedTemplate() && "No class template?");
68      if (Spec->getSpecializedTemplate()->isMemberSpecialization())
69        break;
70    }
71    // Add template arguments from a function template specialization.
72    else if (FunctionDecl *Function = dyn_cast<FunctionDecl>(Ctx)) {
73      if (!RelativeToPrimary &&
74          Function->getTemplateSpecializationKind()
75                                                  == TSK_ExplicitSpecialization)
76        break;
77
78      if (const TemplateArgumentList *TemplateArgs
79            = Function->getTemplateSpecializationArgs()) {
80        // Add the template arguments for this specialization.
81        Result.addOuterTemplateArguments(TemplateArgs);
82
83        // If this function was instantiated from a specialized member that is
84        // a function template, we're done.
85        assert(Function->getPrimaryTemplate() && "No function template?");
86        if (Function->getPrimaryTemplate()->isMemberSpecialization())
87          break;
88      }
89
90      // If this is a friend declaration and it declares an entity at
91      // namespace scope, take arguments from its lexical parent
92      // instead of its semantic parent.
93      if (Function->getFriendObjectKind() &&
94          Function->getDeclContext()->isFileContext()) {
95        Ctx = Function->getLexicalDeclContext();
96        RelativeToPrimary = false;
97        continue;
98      }
99    }
100
101    Ctx = Ctx->getParent();
102    RelativeToPrimary = false;
103  }
104
105  return Result;
106}
107
108bool Sema::ActiveTemplateInstantiation::isInstantiationRecord() const {
109  switch (Kind) {
110  case TemplateInstantiation:
111  case DefaultTemplateArgumentInstantiation:
112  case DefaultFunctionArgumentInstantiation:
113    return true;
114
115  case ExplicitTemplateArgumentSubstitution:
116  case DeducedTemplateArgumentSubstitution:
117  case PriorTemplateArgumentSubstitution:
118  case DefaultTemplateArgumentChecking:
119    return false;
120  }
121
122  return true;
123}
124
125Sema::InstantiatingTemplate::
126InstantiatingTemplate(Sema &SemaRef, SourceLocation PointOfInstantiation,
127                      Decl *Entity,
128                      SourceRange InstantiationRange)
129  :  SemaRef(SemaRef) {
130
131  Invalid = CheckInstantiationDepth(PointOfInstantiation,
132                                    InstantiationRange);
133  if (!Invalid) {
134    ActiveTemplateInstantiation Inst;
135    Inst.Kind = ActiveTemplateInstantiation::TemplateInstantiation;
136    Inst.PointOfInstantiation = PointOfInstantiation;
137    Inst.Entity = reinterpret_cast<uintptr_t>(Entity);
138    Inst.TemplateArgs = 0;
139    Inst.NumTemplateArgs = 0;
140    Inst.InstantiationRange = InstantiationRange;
141    SemaRef.ActiveTemplateInstantiations.push_back(Inst);
142  }
143}
144
145Sema::InstantiatingTemplate::InstantiatingTemplate(Sema &SemaRef,
146                                         SourceLocation PointOfInstantiation,
147                                         TemplateDecl *Template,
148                                         const TemplateArgument *TemplateArgs,
149                                         unsigned NumTemplateArgs,
150                                         SourceRange InstantiationRange)
151  : SemaRef(SemaRef) {
152
153  Invalid = CheckInstantiationDepth(PointOfInstantiation,
154                                    InstantiationRange);
155  if (!Invalid) {
156    ActiveTemplateInstantiation Inst;
157    Inst.Kind
158      = ActiveTemplateInstantiation::DefaultTemplateArgumentInstantiation;
159    Inst.PointOfInstantiation = PointOfInstantiation;
160    Inst.Entity = reinterpret_cast<uintptr_t>(Template);
161    Inst.TemplateArgs = TemplateArgs;
162    Inst.NumTemplateArgs = NumTemplateArgs;
163    Inst.InstantiationRange = InstantiationRange;
164    SemaRef.ActiveTemplateInstantiations.push_back(Inst);
165  }
166}
167
168Sema::InstantiatingTemplate::InstantiatingTemplate(Sema &SemaRef,
169                                         SourceLocation PointOfInstantiation,
170                                      FunctionTemplateDecl *FunctionTemplate,
171                                        const TemplateArgument *TemplateArgs,
172                                                   unsigned NumTemplateArgs,
173                         ActiveTemplateInstantiation::InstantiationKind Kind,
174                                              SourceRange InstantiationRange)
175: SemaRef(SemaRef) {
176
177  Invalid = CheckInstantiationDepth(PointOfInstantiation,
178                                    InstantiationRange);
179  if (!Invalid) {
180    ActiveTemplateInstantiation Inst;
181    Inst.Kind = Kind;
182    Inst.PointOfInstantiation = PointOfInstantiation;
183    Inst.Entity = reinterpret_cast<uintptr_t>(FunctionTemplate);
184    Inst.TemplateArgs = TemplateArgs;
185    Inst.NumTemplateArgs = NumTemplateArgs;
186    Inst.InstantiationRange = InstantiationRange;
187    SemaRef.ActiveTemplateInstantiations.push_back(Inst);
188
189    if (!Inst.isInstantiationRecord())
190      ++SemaRef.NonInstantiationEntries;
191  }
192}
193
194Sema::InstantiatingTemplate::InstantiatingTemplate(Sema &SemaRef,
195                                         SourceLocation PointOfInstantiation,
196                          ClassTemplatePartialSpecializationDecl *PartialSpec,
197                                         const TemplateArgument *TemplateArgs,
198                                         unsigned NumTemplateArgs,
199                                         SourceRange InstantiationRange)
200  : SemaRef(SemaRef) {
201
202  Invalid = false;
203
204  ActiveTemplateInstantiation Inst;
205  Inst.Kind = ActiveTemplateInstantiation::DeducedTemplateArgumentSubstitution;
206  Inst.PointOfInstantiation = PointOfInstantiation;
207  Inst.Entity = reinterpret_cast<uintptr_t>(PartialSpec);
208  Inst.TemplateArgs = TemplateArgs;
209  Inst.NumTemplateArgs = NumTemplateArgs;
210  Inst.InstantiationRange = InstantiationRange;
211  SemaRef.ActiveTemplateInstantiations.push_back(Inst);
212
213  assert(!Inst.isInstantiationRecord());
214  ++SemaRef.NonInstantiationEntries;
215}
216
217Sema::InstantiatingTemplate::InstantiatingTemplate(Sema &SemaRef,
218                                          SourceLocation PointOfInstantiation,
219                                          ParmVarDecl *Param,
220                                          const TemplateArgument *TemplateArgs,
221                                          unsigned NumTemplateArgs,
222                                          SourceRange InstantiationRange)
223  : SemaRef(SemaRef) {
224
225  Invalid = CheckInstantiationDepth(PointOfInstantiation, InstantiationRange);
226
227  if (!Invalid) {
228    ActiveTemplateInstantiation Inst;
229    Inst.Kind
230      = ActiveTemplateInstantiation::DefaultFunctionArgumentInstantiation;
231    Inst.PointOfInstantiation = PointOfInstantiation;
232    Inst.Entity = reinterpret_cast<uintptr_t>(Param);
233    Inst.TemplateArgs = TemplateArgs;
234    Inst.NumTemplateArgs = NumTemplateArgs;
235    Inst.InstantiationRange = InstantiationRange;
236    SemaRef.ActiveTemplateInstantiations.push_back(Inst);
237  }
238}
239
240Sema::InstantiatingTemplate::
241InstantiatingTemplate(Sema &SemaRef, SourceLocation PointOfInstantiation,
242                      TemplateDecl *Template,
243                      NonTypeTemplateParmDecl *Param,
244                      const TemplateArgument *TemplateArgs,
245                      unsigned NumTemplateArgs,
246                      SourceRange InstantiationRange) : SemaRef(SemaRef) {
247  Invalid = false;
248
249  ActiveTemplateInstantiation Inst;
250  Inst.Kind = ActiveTemplateInstantiation::PriorTemplateArgumentSubstitution;
251  Inst.PointOfInstantiation = PointOfInstantiation;
252  Inst.Template = Template;
253  Inst.Entity = reinterpret_cast<uintptr_t>(Param);
254  Inst.TemplateArgs = TemplateArgs;
255  Inst.NumTemplateArgs = NumTemplateArgs;
256  Inst.InstantiationRange = InstantiationRange;
257  SemaRef.ActiveTemplateInstantiations.push_back(Inst);
258
259  assert(!Inst.isInstantiationRecord());
260  ++SemaRef.NonInstantiationEntries;
261}
262
263Sema::InstantiatingTemplate::
264InstantiatingTemplate(Sema &SemaRef, SourceLocation PointOfInstantiation,
265                      TemplateDecl *Template,
266                      TemplateTemplateParmDecl *Param,
267                      const TemplateArgument *TemplateArgs,
268                      unsigned NumTemplateArgs,
269                      SourceRange InstantiationRange) : SemaRef(SemaRef) {
270  Invalid = false;
271  ActiveTemplateInstantiation Inst;
272  Inst.Kind = ActiveTemplateInstantiation::PriorTemplateArgumentSubstitution;
273  Inst.PointOfInstantiation = PointOfInstantiation;
274  Inst.Template = Template;
275  Inst.Entity = reinterpret_cast<uintptr_t>(Param);
276  Inst.TemplateArgs = TemplateArgs;
277  Inst.NumTemplateArgs = NumTemplateArgs;
278  Inst.InstantiationRange = InstantiationRange;
279  SemaRef.ActiveTemplateInstantiations.push_back(Inst);
280
281  assert(!Inst.isInstantiationRecord());
282  ++SemaRef.NonInstantiationEntries;
283}
284
285Sema::InstantiatingTemplate::
286InstantiatingTemplate(Sema &SemaRef, SourceLocation PointOfInstantiation,
287                      TemplateDecl *Template,
288                      NamedDecl *Param,
289                      const TemplateArgument *TemplateArgs,
290                      unsigned NumTemplateArgs,
291                      SourceRange InstantiationRange) : SemaRef(SemaRef) {
292  Invalid = false;
293
294  ActiveTemplateInstantiation Inst;
295  Inst.Kind = ActiveTemplateInstantiation::DefaultTemplateArgumentChecking;
296  Inst.PointOfInstantiation = PointOfInstantiation;
297  Inst.Template = Template;
298  Inst.Entity = reinterpret_cast<uintptr_t>(Param);
299  Inst.TemplateArgs = TemplateArgs;
300  Inst.NumTemplateArgs = NumTemplateArgs;
301  Inst.InstantiationRange = InstantiationRange;
302  SemaRef.ActiveTemplateInstantiations.push_back(Inst);
303
304  assert(!Inst.isInstantiationRecord());
305  ++SemaRef.NonInstantiationEntries;
306}
307
308void Sema::InstantiatingTemplate::Clear() {
309  if (!Invalid) {
310    if (!SemaRef.ActiveTemplateInstantiations.back().isInstantiationRecord()) {
311      assert(SemaRef.NonInstantiationEntries > 0);
312      --SemaRef.NonInstantiationEntries;
313    }
314
315    SemaRef.ActiveTemplateInstantiations.pop_back();
316    Invalid = true;
317  }
318}
319
320bool Sema::InstantiatingTemplate::CheckInstantiationDepth(
321                                        SourceLocation PointOfInstantiation,
322                                           SourceRange InstantiationRange) {
323  assert(SemaRef.NonInstantiationEntries <=
324                                   SemaRef.ActiveTemplateInstantiations.size());
325  if ((SemaRef.ActiveTemplateInstantiations.size() -
326          SemaRef.NonInstantiationEntries)
327        <= SemaRef.getLangOptions().InstantiationDepth)
328    return false;
329
330  SemaRef.Diag(PointOfInstantiation,
331               diag::err_template_recursion_depth_exceeded)
332    << SemaRef.getLangOptions().InstantiationDepth
333    << InstantiationRange;
334  SemaRef.Diag(PointOfInstantiation, diag::note_template_recursion_depth)
335    << SemaRef.getLangOptions().InstantiationDepth;
336  return true;
337}
338
339/// \brief Prints the current instantiation stack through a series of
340/// notes.
341void Sema::PrintInstantiationStack() {
342  // FIXME: In all of these cases, we need to show the template arguments
343  for (llvm::SmallVector<ActiveTemplateInstantiation, 16>::reverse_iterator
344         Active = ActiveTemplateInstantiations.rbegin(),
345         ActiveEnd = ActiveTemplateInstantiations.rend();
346       Active != ActiveEnd;
347       ++Active) {
348    switch (Active->Kind) {
349    case ActiveTemplateInstantiation::TemplateInstantiation: {
350      Decl *D = reinterpret_cast<Decl *>(Active->Entity);
351      if (CXXRecordDecl *Record = dyn_cast<CXXRecordDecl>(D)) {
352        unsigned DiagID = diag::note_template_member_class_here;
353        if (isa<ClassTemplateSpecializationDecl>(Record))
354          DiagID = diag::note_template_class_instantiation_here;
355        Diags.Report(FullSourceLoc(Active->PointOfInstantiation, SourceMgr),
356                     DiagID)
357          << Context.getTypeDeclType(Record)
358          << Active->InstantiationRange;
359      } else if (FunctionDecl *Function = dyn_cast<FunctionDecl>(D)) {
360        unsigned DiagID;
361        if (Function->getPrimaryTemplate())
362          DiagID = diag::note_function_template_spec_here;
363        else
364          DiagID = diag::note_template_member_function_here;
365        Diags.Report(FullSourceLoc(Active->PointOfInstantiation, SourceMgr),
366                     DiagID)
367          << Function
368          << Active->InstantiationRange;
369      } else {
370        Diags.Report(FullSourceLoc(Active->PointOfInstantiation, SourceMgr),
371                     diag::note_template_static_data_member_def_here)
372          << cast<VarDecl>(D)
373          << Active->InstantiationRange;
374      }
375      break;
376    }
377
378    case ActiveTemplateInstantiation::DefaultTemplateArgumentInstantiation: {
379      TemplateDecl *Template = cast<TemplateDecl>((Decl *)Active->Entity);
380      std::string TemplateArgsStr
381        = TemplateSpecializationType::PrintTemplateArgumentList(
382                                                         Active->TemplateArgs,
383                                                      Active->NumTemplateArgs,
384                                                      Context.PrintingPolicy);
385      Diags.Report(FullSourceLoc(Active->PointOfInstantiation, SourceMgr),
386                   diag::note_default_arg_instantiation_here)
387        << (Template->getNameAsString() + TemplateArgsStr)
388        << Active->InstantiationRange;
389      break;
390    }
391
392    case ActiveTemplateInstantiation::ExplicitTemplateArgumentSubstitution: {
393      FunctionTemplateDecl *FnTmpl
394        = cast<FunctionTemplateDecl>((Decl *)Active->Entity);
395      Diags.Report(FullSourceLoc(Active->PointOfInstantiation, SourceMgr),
396                   diag::note_explicit_template_arg_substitution_here)
397        << FnTmpl << Active->InstantiationRange;
398      break;
399    }
400
401    case ActiveTemplateInstantiation::DeducedTemplateArgumentSubstitution:
402      if (ClassTemplatePartialSpecializationDecl *PartialSpec
403            = dyn_cast<ClassTemplatePartialSpecializationDecl>(
404                                                    (Decl *)Active->Entity)) {
405        Diags.Report(FullSourceLoc(Active->PointOfInstantiation, SourceMgr),
406                     diag::note_partial_spec_deduct_instantiation_here)
407          << Context.getTypeDeclType(PartialSpec)
408          << Active->InstantiationRange;
409      } else {
410        FunctionTemplateDecl *FnTmpl
411          = cast<FunctionTemplateDecl>((Decl *)Active->Entity);
412        Diags.Report(FullSourceLoc(Active->PointOfInstantiation, SourceMgr),
413                     diag::note_function_template_deduction_instantiation_here)
414          << FnTmpl << Active->InstantiationRange;
415      }
416      break;
417
418    case ActiveTemplateInstantiation::DefaultFunctionArgumentInstantiation: {
419      ParmVarDecl *Param = cast<ParmVarDecl>((Decl *)Active->Entity);
420      FunctionDecl *FD = cast<FunctionDecl>(Param->getDeclContext());
421
422      std::string TemplateArgsStr
423        = TemplateSpecializationType::PrintTemplateArgumentList(
424                                                         Active->TemplateArgs,
425                                                      Active->NumTemplateArgs,
426                                                      Context.PrintingPolicy);
427      Diags.Report(FullSourceLoc(Active->PointOfInstantiation, SourceMgr),
428                   diag::note_default_function_arg_instantiation_here)
429        << (FD->getNameAsString() + TemplateArgsStr)
430        << Active->InstantiationRange;
431      break;
432    }
433
434    case ActiveTemplateInstantiation::PriorTemplateArgumentSubstitution: {
435      NamedDecl *Parm = cast<NamedDecl>((Decl *)Active->Entity);
436      std::string Name;
437      if (!Parm->getName().empty())
438        Name = std::string(" '") + Parm->getName().str() + "'";
439
440      Diags.Report(FullSourceLoc(Active->PointOfInstantiation, SourceMgr),
441                   diag::note_prior_template_arg_substitution)
442        << isa<TemplateTemplateParmDecl>(Parm)
443        << Name
444        << getTemplateArgumentBindingsText(
445                                    Active->Template->getTemplateParameters(),
446                                           Active->TemplateArgs,
447                                           Active->NumTemplateArgs)
448        << Active->InstantiationRange;
449      break;
450    }
451
452    case ActiveTemplateInstantiation::DefaultTemplateArgumentChecking: {
453      Diags.Report(FullSourceLoc(Active->PointOfInstantiation, SourceMgr),
454                   diag::note_template_default_arg_checking)
455        << getTemplateArgumentBindingsText(
456                                     Active->Template->getTemplateParameters(),
457                                           Active->TemplateArgs,
458                                           Active->NumTemplateArgs)
459        << Active->InstantiationRange;
460      break;
461    }
462    }
463  }
464}
465
466bool Sema::isSFINAEContext() const {
467  using llvm::SmallVector;
468  for (SmallVector<ActiveTemplateInstantiation, 16>::const_reverse_iterator
469         Active = ActiveTemplateInstantiations.rbegin(),
470         ActiveEnd = ActiveTemplateInstantiations.rend();
471       Active != ActiveEnd;
472       ++Active)
473  {
474    switch(Active->Kind) {
475    case ActiveTemplateInstantiation::TemplateInstantiation:
476    case ActiveTemplateInstantiation::DefaultFunctionArgumentInstantiation:
477      // This is a template instantiation, so there is no SFINAE.
478      return false;
479
480    case ActiveTemplateInstantiation::DefaultTemplateArgumentInstantiation:
481    case ActiveTemplateInstantiation::PriorTemplateArgumentSubstitution:
482    case ActiveTemplateInstantiation::DefaultTemplateArgumentChecking:
483      // A default template argument instantiation and substitution into
484      // template parameters with arguments for prior parameters may or may
485      // not be a SFINAE context; look further up the stack.
486      break;
487
488    case ActiveTemplateInstantiation::ExplicitTemplateArgumentSubstitution:
489    case ActiveTemplateInstantiation::DeducedTemplateArgumentSubstitution:
490      // We're either substitution explicitly-specified template arguments
491      // or deduced template arguments, so SFINAE applies.
492      return true;
493    }
494  }
495
496  return false;
497}
498
499//===----------------------------------------------------------------------===/
500// Template Instantiation for Types
501//===----------------------------------------------------------------------===/
502namespace {
503  class TemplateInstantiator
504    : public TreeTransform<TemplateInstantiator> {
505    const MultiLevelTemplateArgumentList &TemplateArgs;
506    SourceLocation Loc;
507    DeclarationName Entity;
508
509  public:
510    typedef TreeTransform<TemplateInstantiator> inherited;
511
512    TemplateInstantiator(Sema &SemaRef,
513                         const MultiLevelTemplateArgumentList &TemplateArgs,
514                         SourceLocation Loc,
515                         DeclarationName Entity)
516      : inherited(SemaRef), TemplateArgs(TemplateArgs), Loc(Loc),
517        Entity(Entity) { }
518
519    /// \brief Determine whether the given type \p T has already been
520    /// transformed.
521    ///
522    /// For the purposes of template instantiation, a type has already been
523    /// transformed if it is NULL or if it is not dependent.
524    bool AlreadyTransformed(QualType T) {
525      return T.isNull() || !T->isDependentType();
526    }
527
528    /// \brief Returns the location of the entity being instantiated, if known.
529    SourceLocation getBaseLocation() { return Loc; }
530
531    /// \brief Returns the name of the entity being instantiated, if any.
532    DeclarationName getBaseEntity() { return Entity; }
533
534    /// \brief Sets the "base" location and entity when that
535    /// information is known based on another transformation.
536    void setBase(SourceLocation Loc, DeclarationName Entity) {
537      this->Loc = Loc;
538      this->Entity = Entity;
539    }
540
541    /// \brief Transform the given declaration by instantiating a reference to
542    /// this declaration.
543    Decl *TransformDecl(Decl *D);
544
545    /// \brief Transform the definition of the given declaration by
546    /// instantiating it.
547    Decl *TransformDefinition(Decl *D);
548
549    /// \bried Transform the first qualifier within a scope by instantiating the
550    /// declaration.
551    NamedDecl *TransformFirstQualifierInScope(NamedDecl *D, SourceLocation Loc);
552
553    /// \brief Rebuild the exception declaration and register the declaration
554    /// as an instantiated local.
555    VarDecl *RebuildExceptionDecl(VarDecl *ExceptionDecl, QualType T,
556                                  TypeSourceInfo *Declarator,
557                                  IdentifierInfo *Name,
558                                  SourceLocation Loc, SourceRange TypeRange);
559
560    /// \brief Check for tag mismatches when instantiating an
561    /// elaborated type.
562    QualType RebuildElaboratedType(QualType T, ElaboratedType::TagKind Tag);
563
564    Sema::OwningExprResult TransformPredefinedExpr(PredefinedExpr *E);
565    Sema::OwningExprResult TransformDeclRefExpr(DeclRefExpr *E);
566    Sema::OwningExprResult TransformCXXDefaultArgExpr(CXXDefaultArgExpr *E);
567    Sema::OwningExprResult TransformTemplateParmRefExpr(DeclRefExpr *E,
568                                                NonTypeTemplateParmDecl *D);
569
570    /// \brief Transforms a template type parameter type by performing
571    /// substitution of the corresponding template type argument.
572    QualType TransformTemplateTypeParmType(TypeLocBuilder &TLB,
573                                           TemplateTypeParmTypeLoc TL,
574                                           QualType ObjectType);
575  };
576}
577
578Decl *TemplateInstantiator::TransformDecl(Decl *D) {
579  if (!D)
580    return 0;
581
582  if (TemplateTemplateParmDecl *TTP = dyn_cast<TemplateTemplateParmDecl>(D)) {
583    if (TTP->getDepth() < TemplateArgs.getNumLevels()) {
584      // If the corresponding template argument is NULL or non-existent, it's
585      // because we are performing instantiation from explicitly-specified
586      // template arguments in a function template, but there were some
587      // arguments left unspecified.
588      if (!TemplateArgs.hasTemplateArgument(TTP->getDepth(),
589                                            TTP->getPosition()))
590        return D;
591
592      TemplateName Template
593        = TemplateArgs(TTP->getDepth(), TTP->getPosition()).getAsTemplate();
594      assert(!Template.isNull() && Template.getAsTemplateDecl() &&
595             "Wrong kind of template template argument");
596      return Template.getAsTemplateDecl();
597    }
598
599    // Fall through to find the instantiated declaration for this template
600    // template parameter.
601  }
602
603  return SemaRef.FindInstantiatedDecl(cast<NamedDecl>(D), TemplateArgs);
604}
605
606Decl *TemplateInstantiator::TransformDefinition(Decl *D) {
607  Decl *Inst = getSema().SubstDecl(D, getSema().CurContext, TemplateArgs);
608  if (!Inst)
609    return 0;
610
611  getSema().CurrentInstantiationScope->InstantiatedLocal(D, Inst);
612  return Inst;
613}
614
615NamedDecl *
616TemplateInstantiator::TransformFirstQualifierInScope(NamedDecl *D,
617                                                     SourceLocation Loc) {
618  // If the first part of the nested-name-specifier was a template type
619  // parameter, instantiate that type parameter down to a tag type.
620  if (TemplateTypeParmDecl *TTPD = dyn_cast_or_null<TemplateTypeParmDecl>(D)) {
621    const TemplateTypeParmType *TTP
622      = cast<TemplateTypeParmType>(getSema().Context.getTypeDeclType(TTPD));
623    if (TTP->getDepth() < TemplateArgs.getNumLevels()) {
624      QualType T = TemplateArgs(TTP->getDepth(), TTP->getIndex()).getAsType();
625      if (T.isNull())
626        return cast_or_null<NamedDecl>(TransformDecl(D));
627
628      if (const TagType *Tag = T->getAs<TagType>())
629        return Tag->getDecl();
630
631      // The resulting type is not a tag; complain.
632      getSema().Diag(Loc, diag::err_nested_name_spec_non_tag) << T;
633      return 0;
634    }
635  }
636
637  return cast_or_null<NamedDecl>(TransformDecl(D));
638}
639
640VarDecl *
641TemplateInstantiator::RebuildExceptionDecl(VarDecl *ExceptionDecl,
642                                           QualType T,
643                                           TypeSourceInfo *Declarator,
644                                           IdentifierInfo *Name,
645                                           SourceLocation Loc,
646                                           SourceRange TypeRange) {
647  VarDecl *Var = inherited::RebuildExceptionDecl(ExceptionDecl, T, Declarator,
648                                                 Name, Loc, TypeRange);
649  if (Var && !Var->isInvalidDecl())
650    getSema().CurrentInstantiationScope->InstantiatedLocal(ExceptionDecl, Var);
651  return Var;
652}
653
654QualType
655TemplateInstantiator::RebuildElaboratedType(QualType T,
656                                            ElaboratedType::TagKind Tag) {
657  if (const TagType *TT = T->getAs<TagType>()) {
658    TagDecl* TD = TT->getDecl();
659
660    // FIXME: this location is very wrong;  we really need typelocs.
661    SourceLocation TagLocation = TD->getTagKeywordLoc();
662
663    // FIXME: type might be anonymous.
664    IdentifierInfo *Id = TD->getIdentifier();
665
666    // TODO: should we even warn on struct/class mismatches for this?  Seems
667    // like it's likely to produce a lot of spurious errors.
668    if (!SemaRef.isAcceptableTagRedeclaration(TD, Tag, TagLocation, *Id)) {
669      SemaRef.Diag(TagLocation, diag::err_use_with_wrong_tag)
670        << Id
671        << CodeModificationHint::CreateReplacement(SourceRange(TagLocation),
672                                                   TD->getKindName());
673      SemaRef.Diag(TD->getLocation(), diag::note_previous_use);
674    }
675  }
676
677  return TreeTransform<TemplateInstantiator>::RebuildElaboratedType(T, Tag);
678}
679
680Sema::OwningExprResult
681TemplateInstantiator::TransformPredefinedExpr(PredefinedExpr *E) {
682  if (!E->isTypeDependent())
683    return SemaRef.Owned(E->Retain());
684
685  FunctionDecl *currentDecl = getSema().getCurFunctionDecl();
686  assert(currentDecl && "Must have current function declaration when "
687                        "instantiating.");
688
689  PredefinedExpr::IdentType IT = E->getIdentType();
690
691  unsigned Length = PredefinedExpr::ComputeName(IT, currentDecl).length();
692
693  llvm::APInt LengthI(32, Length + 1);
694  QualType ResTy = getSema().Context.CharTy.withConst();
695  ResTy = getSema().Context.getConstantArrayType(ResTy, LengthI,
696                                                 ArrayType::Normal, 0);
697  PredefinedExpr *PE =
698    new (getSema().Context) PredefinedExpr(E->getLocation(), ResTy, IT);
699  return getSema().Owned(PE);
700}
701
702Sema::OwningExprResult
703TemplateInstantiator::TransformTemplateParmRefExpr(DeclRefExpr *E,
704                                               NonTypeTemplateParmDecl *NTTP) {
705  // If the corresponding template argument is NULL or non-existent, it's
706  // because we are performing instantiation from explicitly-specified
707  // template arguments in a function template, but there were some
708  // arguments left unspecified.
709  if (!TemplateArgs.hasTemplateArgument(NTTP->getDepth(),
710                                        NTTP->getPosition()))
711    return SemaRef.Owned(E->Retain());
712
713  const TemplateArgument &Arg = TemplateArgs(NTTP->getDepth(),
714                                             NTTP->getPosition());
715
716  // The template argument itself might be an expression, in which
717  // case we just return that expression.
718  if (Arg.getKind() == TemplateArgument::Expression)
719    return SemaRef.Owned(Arg.getAsExpr()->Retain());
720
721  if (Arg.getKind() == TemplateArgument::Declaration) {
722    ValueDecl *VD = cast<ValueDecl>(Arg.getAsDecl());
723
724    // Find the instantiation of the template argument.  This is
725    // required for nested templates.
726    VD = cast_or_null<ValueDecl>(
727                              getSema().FindInstantiatedDecl(VD, TemplateArgs));
728    if (!VD)
729      return SemaRef.ExprError();
730
731    // Derive the type we want the substituted decl to have.  This had
732    // better be non-dependent, or these checks will have serious problems.
733    QualType TargetType = SemaRef.SubstType(NTTP->getType(), TemplateArgs,
734                                            E->getLocation(),
735                                            DeclarationName());
736    assert(!TargetType.isNull() && "type substitution failed for param type");
737    assert(!TargetType->isDependentType() && "param type still dependent");
738
739    if (VD->getDeclContext()->isRecord() &&
740        (isa<CXXMethodDecl>(VD) || isa<FieldDecl>(VD))) {
741      // If the value is a class member, we might have a pointer-to-member.
742      // Determine whether the non-type template template parameter is of
743      // pointer-to-member type. If so, we need to build an appropriate
744      // expression for a pointer-to-member, since a "normal" DeclRefExpr
745      // would refer to the member itself.
746      if (TargetType->isMemberPointerType()) {
747        QualType ClassType
748          = SemaRef.Context.getTypeDeclType(
749                                        cast<RecordDecl>(VD->getDeclContext()));
750        NestedNameSpecifier *Qualifier
751          = NestedNameSpecifier::Create(SemaRef.Context, 0, false,
752                                        ClassType.getTypePtr());
753        CXXScopeSpec SS;
754        SS.setScopeRep(Qualifier);
755        OwningExprResult RefExpr
756          = SemaRef.BuildDeclRefExpr(VD,
757                                     VD->getType().getNonReferenceType(),
758                                     E->getLocation(),
759                                     &SS);
760        if (RefExpr.isInvalid())
761          return SemaRef.ExprError();
762
763        RefExpr = SemaRef.CreateBuiltinUnaryOp(E->getLocation(),
764                                               UnaryOperator::AddrOf,
765                                               move(RefExpr));
766        assert(!RefExpr.isInvalid() &&
767               SemaRef.Context.hasSameType(((Expr*) RefExpr.get())->getType(),
768                                           TargetType));
769        return move(RefExpr);
770      }
771    }
772
773    QualType T = VD->getType().getNonReferenceType();
774
775    if (TargetType->isPointerType()) {
776      // C++03 [temp.arg.nontype]p5:
777      //  - For a non-type template-parameter of type pointer to
778      //    object, qualification conversions and the array-to-pointer
779      //    conversion are applied.
780      //  - For a non-type template-parameter of type pointer to
781      //    function, only the function-to-pointer conversion is
782      //    applied.
783
784      OwningExprResult RefExpr
785        = SemaRef.BuildDeclRefExpr(VD, T, E->getLocation());
786      if (RefExpr.isInvalid())
787        return SemaRef.ExprError();
788
789      // Decay functions and arrays.
790      Expr *RefE = (Expr *)RefExpr.get();
791      SemaRef.DefaultFunctionArrayConversion(RefE);
792      if (RefE != RefExpr.get()) {
793        RefExpr.release();
794        RefExpr = SemaRef.Owned(RefE);
795      }
796
797      // Qualification conversions.
798      RefExpr.release();
799      SemaRef.ImpCastExprToType(RefE, TargetType.getUnqualifiedType(),
800                                CastExpr::CK_NoOp);
801      return SemaRef.Owned(RefE);
802    }
803
804    // If the non-type template parameter has reference type, qualify the
805    // resulting declaration reference with the extra qualifiers on the
806    // type that the reference refers to.
807    if (const ReferenceType *TargetRef = TargetType->getAs<ReferenceType>())
808      T = SemaRef.Context.getQualifiedType(T,
809                                  TargetRef->getPointeeType().getQualifiers());
810
811    return SemaRef.BuildDeclRefExpr(VD, T, E->getLocation());
812  }
813
814  assert(Arg.getKind() == TemplateArgument::Integral);
815  QualType T = Arg.getIntegralType();
816  if (T->isCharType() || T->isWideCharType())
817    return SemaRef.Owned(new (SemaRef.Context) CharacterLiteral(
818                                              Arg.getAsIntegral()->getZExtValue(),
819                                              T->isWideCharType(),
820                                              T,
821                                              E->getSourceRange().getBegin()));
822  if (T->isBooleanType())
823    return SemaRef.Owned(new (SemaRef.Context) CXXBoolLiteralExpr(
824                                            Arg.getAsIntegral()->getBoolValue(),
825                                            T,
826                                            E->getSourceRange().getBegin()));
827
828  assert(Arg.getAsIntegral()->getBitWidth() == SemaRef.Context.getIntWidth(T));
829  return SemaRef.Owned(new (SemaRef.Context) IntegerLiteral(
830                                                *Arg.getAsIntegral(),
831                                                T,
832                                                E->getSourceRange().getBegin()));
833}
834
835
836Sema::OwningExprResult
837TemplateInstantiator::TransformDeclRefExpr(DeclRefExpr *E) {
838  NamedDecl *D = E->getDecl();
839  if (NonTypeTemplateParmDecl *NTTP = dyn_cast<NonTypeTemplateParmDecl>(D)) {
840    if (NTTP->getDepth() < TemplateArgs.getNumLevels())
841      return TransformTemplateParmRefExpr(E, NTTP);
842
843    // We have a non-type template parameter that isn't fully substituted;
844    // FindInstantiatedDecl will find it in the local instantiation scope.
845  }
846
847  return TreeTransform<TemplateInstantiator>::TransformDeclRefExpr(E);
848}
849
850Sema::OwningExprResult TemplateInstantiator::TransformCXXDefaultArgExpr(
851    CXXDefaultArgExpr *E) {
852  assert(!cast<FunctionDecl>(E->getParam()->getDeclContext())->
853             getDescribedFunctionTemplate() &&
854         "Default arg expressions are never formed in dependent cases.");
855  return SemaRef.BuildCXXDefaultArgExpr(E->getUsedLocation(),
856                           cast<FunctionDecl>(E->getParam()->getDeclContext()),
857                                        E->getParam());
858}
859
860
861QualType
862TemplateInstantiator::TransformTemplateTypeParmType(TypeLocBuilder &TLB,
863                                                TemplateTypeParmTypeLoc TL,
864                                                    QualType ObjectType) {
865  TemplateTypeParmType *T = TL.getTypePtr();
866  if (T->getDepth() < TemplateArgs.getNumLevels()) {
867    // Replace the template type parameter with its corresponding
868    // template argument.
869
870    // If the corresponding template argument is NULL or doesn't exist, it's
871    // because we are performing instantiation from explicitly-specified
872    // template arguments in a function template class, but there were some
873    // arguments left unspecified.
874    if (!TemplateArgs.hasTemplateArgument(T->getDepth(), T->getIndex())) {
875      TemplateTypeParmTypeLoc NewTL
876        = TLB.push<TemplateTypeParmTypeLoc>(TL.getType());
877      NewTL.setNameLoc(TL.getNameLoc());
878      return TL.getType();
879    }
880
881    assert(TemplateArgs(T->getDepth(), T->getIndex()).getKind()
882             == TemplateArgument::Type &&
883           "Template argument kind mismatch");
884
885    QualType Replacement
886      = TemplateArgs(T->getDepth(), T->getIndex()).getAsType();
887
888    // TODO: only do this uniquing once, at the start of instantiation.
889    QualType Result
890      = getSema().Context.getSubstTemplateTypeParmType(T, Replacement);
891    SubstTemplateTypeParmTypeLoc NewTL
892      = TLB.push<SubstTemplateTypeParmTypeLoc>(Result);
893    NewTL.setNameLoc(TL.getNameLoc());
894    return Result;
895  }
896
897  // The template type parameter comes from an inner template (e.g.,
898  // the template parameter list of a member template inside the
899  // template we are instantiating). Create a new template type
900  // parameter with the template "level" reduced by one.
901  QualType Result
902    = getSema().Context.getTemplateTypeParmType(T->getDepth()
903                                                 - TemplateArgs.getNumLevels(),
904                                                T->getIndex(),
905                                                T->isParameterPack(),
906                                                T->getName());
907  TemplateTypeParmTypeLoc NewTL = TLB.push<TemplateTypeParmTypeLoc>(Result);
908  NewTL.setNameLoc(TL.getNameLoc());
909  return Result;
910}
911
912/// \brief Perform substitution on the type T with a given set of template
913/// arguments.
914///
915/// This routine substitutes the given template arguments into the
916/// type T and produces the instantiated type.
917///
918/// \param T the type into which the template arguments will be
919/// substituted. If this type is not dependent, it will be returned
920/// immediately.
921///
922/// \param TemplateArgs the template arguments that will be
923/// substituted for the top-level template parameters within T.
924///
925/// \param Loc the location in the source code where this substitution
926/// is being performed. It will typically be the location of the
927/// declarator (if we're instantiating the type of some declaration)
928/// or the location of the type in the source code (if, e.g., we're
929/// instantiating the type of a cast expression).
930///
931/// \param Entity the name of the entity associated with a declaration
932/// being instantiated (if any). May be empty to indicate that there
933/// is no such entity (if, e.g., this is a type that occurs as part of
934/// a cast expression) or that the entity has no name (e.g., an
935/// unnamed function parameter).
936///
937/// \returns If the instantiation succeeds, the instantiated
938/// type. Otherwise, produces diagnostics and returns a NULL type.
939TypeSourceInfo *Sema::SubstType(TypeSourceInfo *T,
940                                const MultiLevelTemplateArgumentList &Args,
941                                SourceLocation Loc,
942                                DeclarationName Entity) {
943  assert(!ActiveTemplateInstantiations.empty() &&
944         "Cannot perform an instantiation without some context on the "
945         "instantiation stack");
946
947  if (!T->getType()->isDependentType())
948    return T;
949
950  TemplateInstantiator Instantiator(*this, Args, Loc, Entity);
951  return Instantiator.TransformType(T);
952}
953
954/// Deprecated form of the above.
955QualType Sema::SubstType(QualType T,
956                         const MultiLevelTemplateArgumentList &TemplateArgs,
957                         SourceLocation Loc, DeclarationName Entity) {
958  assert(!ActiveTemplateInstantiations.empty() &&
959         "Cannot perform an instantiation without some context on the "
960         "instantiation stack");
961
962  // If T is not a dependent type, there is nothing to do.
963  if (!T->isDependentType())
964    return T;
965
966  TemplateInstantiator Instantiator(*this, TemplateArgs, Loc, Entity);
967  return Instantiator.TransformType(T);
968}
969
970/// \brief Perform substitution on the base class specifiers of the
971/// given class template specialization.
972///
973/// Produces a diagnostic and returns true on error, returns false and
974/// attaches the instantiated base classes to the class template
975/// specialization if successful.
976bool
977Sema::SubstBaseSpecifiers(CXXRecordDecl *Instantiation,
978                          CXXRecordDecl *Pattern,
979                          const MultiLevelTemplateArgumentList &TemplateArgs) {
980  bool Invalid = false;
981  llvm::SmallVector<CXXBaseSpecifier*, 4> InstantiatedBases;
982  for (ClassTemplateSpecializationDecl::base_class_iterator
983         Base = Pattern->bases_begin(), BaseEnd = Pattern->bases_end();
984       Base != BaseEnd; ++Base) {
985    if (!Base->getType()->isDependentType()) {
986      const CXXRecordDecl *BaseDecl =
987        cast<CXXRecordDecl>(Base->getType()->getAs<RecordType>()->getDecl());
988
989      // Make sure to set the attributes from the base.
990      SetClassDeclAttributesFromBase(Instantiation, BaseDecl,
991                                     Base->isVirtual());
992
993      InstantiatedBases.push_back(new (Context) CXXBaseSpecifier(*Base));
994      continue;
995    }
996
997    QualType BaseType = SubstType(Base->getType(),
998                                  TemplateArgs,
999                                  Base->getSourceRange().getBegin(),
1000                                  DeclarationName());
1001    if (BaseType.isNull()) {
1002      Invalid = true;
1003      continue;
1004    }
1005
1006    if (CXXBaseSpecifier *InstantiatedBase
1007          = CheckBaseSpecifier(Instantiation,
1008                               Base->getSourceRange(),
1009                               Base->isVirtual(),
1010                               Base->getAccessSpecifierAsWritten(),
1011                               BaseType,
1012                               /*FIXME: Not totally accurate */
1013                               Base->getSourceRange().getBegin()))
1014      InstantiatedBases.push_back(InstantiatedBase);
1015    else
1016      Invalid = true;
1017  }
1018
1019  if (!Invalid &&
1020      AttachBaseSpecifiers(Instantiation, InstantiatedBases.data(),
1021                           InstantiatedBases.size()))
1022    Invalid = true;
1023
1024  return Invalid;
1025}
1026
1027/// \brief Instantiate the definition of a class from a given pattern.
1028///
1029/// \param PointOfInstantiation The point of instantiation within the
1030/// source code.
1031///
1032/// \param Instantiation is the declaration whose definition is being
1033/// instantiated. This will be either a class template specialization
1034/// or a member class of a class template specialization.
1035///
1036/// \param Pattern is the pattern from which the instantiation
1037/// occurs. This will be either the declaration of a class template or
1038/// the declaration of a member class of a class template.
1039///
1040/// \param TemplateArgs The template arguments to be substituted into
1041/// the pattern.
1042///
1043/// \param TSK the kind of implicit or explicit instantiation to perform.
1044///
1045/// \param Complain whether to complain if the class cannot be instantiated due
1046/// to the lack of a definition.
1047///
1048/// \returns true if an error occurred, false otherwise.
1049bool
1050Sema::InstantiateClass(SourceLocation PointOfInstantiation,
1051                       CXXRecordDecl *Instantiation, CXXRecordDecl *Pattern,
1052                       const MultiLevelTemplateArgumentList &TemplateArgs,
1053                       TemplateSpecializationKind TSK,
1054                       bool Complain) {
1055  bool Invalid = false;
1056
1057  CXXRecordDecl *PatternDef
1058    = cast_or_null<CXXRecordDecl>(Pattern->getDefinition());
1059  if (!PatternDef) {
1060    if (!Complain) {
1061      // Say nothing
1062    } else if (Pattern == Instantiation->getInstantiatedFromMemberClass()) {
1063      Diag(PointOfInstantiation,
1064           diag::err_implicit_instantiate_member_undefined)
1065        << Context.getTypeDeclType(Instantiation);
1066      Diag(Pattern->getLocation(), diag::note_member_of_template_here);
1067    } else {
1068      Diag(PointOfInstantiation, diag::err_template_instantiate_undefined)
1069        << (TSK != TSK_ImplicitInstantiation)
1070        << Context.getTypeDeclType(Instantiation);
1071      Diag(Pattern->getLocation(), diag::note_template_decl_here);
1072    }
1073    return true;
1074  }
1075  Pattern = PatternDef;
1076
1077  // \brief Record the point of instantiation.
1078  if (MemberSpecializationInfo *MSInfo
1079        = Instantiation->getMemberSpecializationInfo()) {
1080    MSInfo->setTemplateSpecializationKind(TSK);
1081    MSInfo->setPointOfInstantiation(PointOfInstantiation);
1082  } else if (ClassTemplateSpecializationDecl *Spec
1083               = dyn_cast<ClassTemplateSpecializationDecl>(Instantiation)) {
1084    Spec->setTemplateSpecializationKind(TSK);
1085    Spec->setPointOfInstantiation(PointOfInstantiation);
1086  }
1087
1088  InstantiatingTemplate Inst(*this, PointOfInstantiation, Instantiation);
1089  if (Inst)
1090    return true;
1091
1092  // Enter the scope of this instantiation. We don't use
1093  // PushDeclContext because we don't have a scope.
1094  DeclContext *PreviousContext = CurContext;
1095  CurContext = Instantiation;
1096
1097  // Start the definition of this instantiation.
1098  Instantiation->startDefinition();
1099
1100  // Do substitution on the base class specifiers.
1101  if (SubstBaseSpecifiers(Instantiation, Pattern, TemplateArgs))
1102    Invalid = true;
1103
1104  llvm::SmallVector<DeclPtrTy, 4> Fields;
1105  for (RecordDecl::decl_iterator Member = Pattern->decls_begin(),
1106         MemberEnd = Pattern->decls_end();
1107       Member != MemberEnd; ++Member) {
1108    Decl *NewMember = SubstDecl(*Member, Instantiation, TemplateArgs);
1109    if (NewMember) {
1110      if (FieldDecl *Field = dyn_cast<FieldDecl>(NewMember))
1111        Fields.push_back(DeclPtrTy::make(Field));
1112      else if (NewMember->isInvalidDecl())
1113        Invalid = true;
1114    } else {
1115      // FIXME: Eventually, a NULL return will mean that one of the
1116      // instantiations was a semantic disaster, and we'll want to set Invalid =
1117      // true. For now, we expect to skip some members that we can't yet handle.
1118    }
1119  }
1120
1121  // Finish checking fields.
1122  ActOnFields(0, Instantiation->getLocation(), DeclPtrTy::make(Instantiation),
1123              Fields.data(), Fields.size(), SourceLocation(), SourceLocation(),
1124              0);
1125  CheckCompletedCXXClass(Instantiation);
1126  if (Instantiation->isInvalidDecl())
1127    Invalid = true;
1128
1129  // Exit the scope of this instantiation.
1130  CurContext = PreviousContext;
1131
1132  // If this is a polymorphic C++ class without a key function, we'll
1133  // have to mark all of the virtual members to allow emission of a vtable
1134  // in this translation unit.
1135  if (Instantiation->isDynamicClass() &&
1136      !Context.getKeyFunction(Instantiation)) {
1137    // Local classes need to have their methods instantiated immediately in
1138    // order to have the correct instantiation scope.
1139    if (Instantiation->isLocalClass()) {
1140      MarkVirtualMembersReferenced(PointOfInstantiation,
1141                                   Instantiation);
1142    } else {
1143      ClassesWithUnmarkedVirtualMembers.push_back(std::make_pair(Instantiation,
1144                                                       PointOfInstantiation));
1145    }
1146  }
1147
1148  if (!Invalid)
1149    Consumer.HandleTagDeclDefinition(Instantiation);
1150
1151  return Invalid;
1152}
1153
1154bool
1155Sema::InstantiateClassTemplateSpecialization(
1156                           SourceLocation PointOfInstantiation,
1157                           ClassTemplateSpecializationDecl *ClassTemplateSpec,
1158                           TemplateSpecializationKind TSK,
1159                           bool Complain) {
1160  // Perform the actual instantiation on the canonical declaration.
1161  ClassTemplateSpec = cast<ClassTemplateSpecializationDecl>(
1162                                         ClassTemplateSpec->getCanonicalDecl());
1163
1164  // Check whether we have already instantiated or specialized this class
1165  // template specialization.
1166  if (ClassTemplateSpec->getSpecializationKind() != TSK_Undeclared) {
1167    if (ClassTemplateSpec->getSpecializationKind() ==
1168          TSK_ExplicitInstantiationDeclaration &&
1169        TSK == TSK_ExplicitInstantiationDefinition) {
1170      // An explicit instantiation definition follows an explicit instantiation
1171      // declaration (C++0x [temp.explicit]p10); go ahead and perform the
1172      // explicit instantiation.
1173      ClassTemplateSpec->setSpecializationKind(TSK);
1174      return false;
1175    }
1176
1177    // We can only instantiate something that hasn't already been
1178    // instantiated or specialized. Fail without any diagnostics: our
1179    // caller will provide an error message.
1180    return true;
1181  }
1182
1183  if (ClassTemplateSpec->isInvalidDecl())
1184    return true;
1185
1186  ClassTemplateDecl *Template = ClassTemplateSpec->getSpecializedTemplate();
1187  CXXRecordDecl *Pattern = 0;
1188
1189  // C++ [temp.class.spec.match]p1:
1190  //   When a class template is used in a context that requires an
1191  //   instantiation of the class, it is necessary to determine
1192  //   whether the instantiation is to be generated using the primary
1193  //   template or one of the partial specializations. This is done by
1194  //   matching the template arguments of the class template
1195  //   specialization with the template argument lists of the partial
1196  //   specializations.
1197  typedef std::pair<ClassTemplatePartialSpecializationDecl *,
1198                    TemplateArgumentList *> MatchResult;
1199  llvm::SmallVector<MatchResult, 4> Matched;
1200  for (llvm::FoldingSet<ClassTemplatePartialSpecializationDecl>::iterator
1201         Partial = Template->getPartialSpecializations().begin(),
1202         PartialEnd = Template->getPartialSpecializations().end();
1203       Partial != PartialEnd;
1204       ++Partial) {
1205    TemplateDeductionInfo Info(Context, PointOfInstantiation);
1206    if (TemplateDeductionResult Result
1207          = DeduceTemplateArguments(&*Partial,
1208                                    ClassTemplateSpec->getTemplateArgs(),
1209                                    Info)) {
1210      // FIXME: Store the failed-deduction information for use in
1211      // diagnostics, later.
1212      (void)Result;
1213    } else {
1214      Matched.push_back(std::make_pair(&*Partial, Info.take()));
1215    }
1216  }
1217
1218  if (Matched.size() >= 1) {
1219    llvm::SmallVector<MatchResult, 4>::iterator Best = Matched.begin();
1220    if (Matched.size() == 1) {
1221      //   -- If exactly one matching specialization is found, the
1222      //      instantiation is generated from that specialization.
1223      // We don't need to do anything for this.
1224    } else {
1225      //   -- If more than one matching specialization is found, the
1226      //      partial order rules (14.5.4.2) are used to determine
1227      //      whether one of the specializations is more specialized
1228      //      than the others. If none of the specializations is more
1229      //      specialized than all of the other matching
1230      //      specializations, then the use of the class template is
1231      //      ambiguous and the program is ill-formed.
1232      for (llvm::SmallVector<MatchResult, 4>::iterator P = Best + 1,
1233                                                    PEnd = Matched.end();
1234           P != PEnd; ++P) {
1235        if (getMoreSpecializedPartialSpecialization(P->first, Best->first,
1236                                                    PointOfInstantiation)
1237              == P->first)
1238          Best = P;
1239      }
1240
1241      // Determine if the best partial specialization is more specialized than
1242      // the others.
1243      bool Ambiguous = false;
1244      for (llvm::SmallVector<MatchResult, 4>::iterator P = Matched.begin(),
1245                                                    PEnd = Matched.end();
1246           P != PEnd; ++P) {
1247        if (P != Best &&
1248            getMoreSpecializedPartialSpecialization(P->first, Best->first,
1249                                                    PointOfInstantiation)
1250              != Best->first) {
1251          Ambiguous = true;
1252          break;
1253        }
1254      }
1255
1256      if (Ambiguous) {
1257        // Partial ordering did not produce a clear winner. Complain.
1258        ClassTemplateSpec->setInvalidDecl();
1259        Diag(PointOfInstantiation, diag::err_partial_spec_ordering_ambiguous)
1260          << ClassTemplateSpec;
1261
1262        // Print the matching partial specializations.
1263        for (llvm::SmallVector<MatchResult, 4>::iterator P = Matched.begin(),
1264                                                      PEnd = Matched.end();
1265             P != PEnd; ++P)
1266          Diag(P->first->getLocation(), diag::note_partial_spec_match)
1267            << getTemplateArgumentBindingsText(P->first->getTemplateParameters(),
1268                                               *P->second);
1269
1270        return true;
1271      }
1272    }
1273
1274    // Instantiate using the best class template partial specialization.
1275    ClassTemplatePartialSpecializationDecl *OrigPartialSpec = Best->first;
1276    while (OrigPartialSpec->getInstantiatedFromMember()) {
1277      // If we've found an explicit specialization of this class template,
1278      // stop here and use that as the pattern.
1279      if (OrigPartialSpec->isMemberSpecialization())
1280        break;
1281
1282      OrigPartialSpec = OrigPartialSpec->getInstantiatedFromMember();
1283    }
1284
1285    Pattern = OrigPartialSpec;
1286    ClassTemplateSpec->setInstantiationOf(Best->first, Best->second);
1287  } else {
1288    //   -- If no matches are found, the instantiation is generated
1289    //      from the primary template.
1290    ClassTemplateDecl *OrigTemplate = Template;
1291    while (OrigTemplate->getInstantiatedFromMemberTemplate()) {
1292      // If we've found an explicit specialization of this class template,
1293      // stop here and use that as the pattern.
1294      if (OrigTemplate->isMemberSpecialization())
1295        break;
1296
1297      OrigTemplate = OrigTemplate->getInstantiatedFromMemberTemplate();
1298    }
1299
1300    Pattern = OrigTemplate->getTemplatedDecl();
1301  }
1302
1303  bool Result = InstantiateClass(PointOfInstantiation, ClassTemplateSpec,
1304                                 Pattern,
1305                                getTemplateInstantiationArgs(ClassTemplateSpec),
1306                                 TSK,
1307                                 Complain);
1308
1309  for (unsigned I = 0, N = Matched.size(); I != N; ++I) {
1310    // FIXME: Implement TemplateArgumentList::Destroy!
1311    //    if (Matched[I].first != Pattern)
1312    //      Matched[I].second->Destroy(Context);
1313  }
1314
1315  return Result;
1316}
1317
1318/// \brief Instantiates the definitions of all of the member
1319/// of the given class, which is an instantiation of a class template
1320/// or a member class of a template.
1321void
1322Sema::InstantiateClassMembers(SourceLocation PointOfInstantiation,
1323                              CXXRecordDecl *Instantiation,
1324                        const MultiLevelTemplateArgumentList &TemplateArgs,
1325                              TemplateSpecializationKind TSK) {
1326  for (DeclContext::decl_iterator D = Instantiation->decls_begin(),
1327                               DEnd = Instantiation->decls_end();
1328       D != DEnd; ++D) {
1329    bool SuppressNew = false;
1330    if (FunctionDecl *Function = dyn_cast<FunctionDecl>(*D)) {
1331      if (FunctionDecl *Pattern
1332            = Function->getInstantiatedFromMemberFunction()) {
1333        MemberSpecializationInfo *MSInfo
1334          = Function->getMemberSpecializationInfo();
1335        assert(MSInfo && "No member specialization information?");
1336        if (CheckSpecializationInstantiationRedecl(PointOfInstantiation, TSK,
1337                                                   Function,
1338                                        MSInfo->getTemplateSpecializationKind(),
1339                                              MSInfo->getPointOfInstantiation(),
1340                                                   SuppressNew) ||
1341            SuppressNew)
1342          continue;
1343
1344        if (Function->getBody())
1345          continue;
1346
1347        if (TSK == TSK_ExplicitInstantiationDefinition) {
1348          // C++0x [temp.explicit]p8:
1349          //   An explicit instantiation definition that names a class template
1350          //   specialization explicitly instantiates the class template
1351          //   specialization and is only an explicit instantiation definition
1352          //   of members whose definition is visible at the point of
1353          //   instantiation.
1354          if (!Pattern->getBody())
1355            continue;
1356
1357          Function->setTemplateSpecializationKind(TSK, PointOfInstantiation);
1358
1359          InstantiateFunctionDefinition(PointOfInstantiation, Function);
1360        } else {
1361          Function->setTemplateSpecializationKind(TSK, PointOfInstantiation);
1362        }
1363      }
1364    } else if (VarDecl *Var = dyn_cast<VarDecl>(*D)) {
1365      if (Var->isStaticDataMember()) {
1366        MemberSpecializationInfo *MSInfo = Var->getMemberSpecializationInfo();
1367        assert(MSInfo && "No member specialization information?");
1368        if (CheckSpecializationInstantiationRedecl(PointOfInstantiation, TSK,
1369                                                   Var,
1370                                        MSInfo->getTemplateSpecializationKind(),
1371                                              MSInfo->getPointOfInstantiation(),
1372                                                   SuppressNew) ||
1373            SuppressNew)
1374          continue;
1375
1376        if (TSK == TSK_ExplicitInstantiationDefinition) {
1377          // C++0x [temp.explicit]p8:
1378          //   An explicit instantiation definition that names a class template
1379          //   specialization explicitly instantiates the class template
1380          //   specialization and is only an explicit instantiation definition
1381          //   of members whose definition is visible at the point of
1382          //   instantiation.
1383          if (!Var->getInstantiatedFromStaticDataMember()
1384                                                     ->getOutOfLineDefinition())
1385            continue;
1386
1387          Var->setTemplateSpecializationKind(TSK, PointOfInstantiation);
1388          InstantiateStaticDataMemberDefinition(PointOfInstantiation, Var);
1389        } else {
1390          Var->setTemplateSpecializationKind(TSK, PointOfInstantiation);
1391        }
1392      }
1393    } else if (CXXRecordDecl *Record = dyn_cast<CXXRecordDecl>(*D)) {
1394      if (Record->isInjectedClassName())
1395        continue;
1396
1397      MemberSpecializationInfo *MSInfo = Record->getMemberSpecializationInfo();
1398      assert(MSInfo && "No member specialization information?");
1399      if (CheckSpecializationInstantiationRedecl(PointOfInstantiation, TSK,
1400                                                 Record,
1401                                        MSInfo->getTemplateSpecializationKind(),
1402                                              MSInfo->getPointOfInstantiation(),
1403                                                 SuppressNew) ||
1404          SuppressNew)
1405        continue;
1406
1407      CXXRecordDecl *Pattern = Record->getInstantiatedFromMemberClass();
1408      assert(Pattern && "Missing instantiated-from-template information");
1409
1410      if (!Record->getDefinition()) {
1411        if (!Pattern->getDefinition()) {
1412          // C++0x [temp.explicit]p8:
1413          //   An explicit instantiation definition that names a class template
1414          //   specialization explicitly instantiates the class template
1415          //   specialization and is only an explicit instantiation definition
1416          //   of members whose definition is visible at the point of
1417          //   instantiation.
1418          if (TSK == TSK_ExplicitInstantiationDeclaration) {
1419            MSInfo->setTemplateSpecializationKind(TSK);
1420            MSInfo->setPointOfInstantiation(PointOfInstantiation);
1421          }
1422
1423          continue;
1424        }
1425
1426        InstantiateClass(PointOfInstantiation, Record, Pattern,
1427                         TemplateArgs,
1428                         TSK);
1429      }
1430
1431      Pattern = cast_or_null<CXXRecordDecl>(Record->getDefinition());
1432      if (Pattern)
1433        InstantiateClassMembers(PointOfInstantiation, Pattern, TemplateArgs,
1434                                TSK);
1435    }
1436  }
1437}
1438
1439/// \brief Instantiate the definitions of all of the members of the
1440/// given class template specialization, which was named as part of an
1441/// explicit instantiation.
1442void
1443Sema::InstantiateClassTemplateSpecializationMembers(
1444                                           SourceLocation PointOfInstantiation,
1445                            ClassTemplateSpecializationDecl *ClassTemplateSpec,
1446                                               TemplateSpecializationKind TSK) {
1447  // C++0x [temp.explicit]p7:
1448  //   An explicit instantiation that names a class template
1449  //   specialization is an explicit instantion of the same kind
1450  //   (declaration or definition) of each of its members (not
1451  //   including members inherited from base classes) that has not
1452  //   been previously explicitly specialized in the translation unit
1453  //   containing the explicit instantiation, except as described
1454  //   below.
1455  InstantiateClassMembers(PointOfInstantiation, ClassTemplateSpec,
1456                          getTemplateInstantiationArgs(ClassTemplateSpec),
1457                          TSK);
1458}
1459
1460Sema::OwningStmtResult
1461Sema::SubstStmt(Stmt *S, const MultiLevelTemplateArgumentList &TemplateArgs) {
1462  if (!S)
1463    return Owned(S);
1464
1465  TemplateInstantiator Instantiator(*this, TemplateArgs,
1466                                    SourceLocation(),
1467                                    DeclarationName());
1468  return Instantiator.TransformStmt(S);
1469}
1470
1471Sema::OwningExprResult
1472Sema::SubstExpr(Expr *E, const MultiLevelTemplateArgumentList &TemplateArgs) {
1473  if (!E)
1474    return Owned(E);
1475
1476  TemplateInstantiator Instantiator(*this, TemplateArgs,
1477                                    SourceLocation(),
1478                                    DeclarationName());
1479  return Instantiator.TransformExpr(E);
1480}
1481
1482/// \brief Do template substitution on a nested-name-specifier.
1483NestedNameSpecifier *
1484Sema::SubstNestedNameSpecifier(NestedNameSpecifier *NNS,
1485                               SourceRange Range,
1486                         const MultiLevelTemplateArgumentList &TemplateArgs) {
1487  TemplateInstantiator Instantiator(*this, TemplateArgs, Range.getBegin(),
1488                                    DeclarationName());
1489  return Instantiator.TransformNestedNameSpecifier(NNS, Range);
1490}
1491
1492TemplateName
1493Sema::SubstTemplateName(TemplateName Name, SourceLocation Loc,
1494                        const MultiLevelTemplateArgumentList &TemplateArgs) {
1495  TemplateInstantiator Instantiator(*this, TemplateArgs, Loc,
1496                                    DeclarationName());
1497  return Instantiator.TransformTemplateName(Name);
1498}
1499
1500bool Sema::Subst(const TemplateArgumentLoc &Input, TemplateArgumentLoc &Output,
1501                 const MultiLevelTemplateArgumentList &TemplateArgs) {
1502  TemplateInstantiator Instantiator(*this, TemplateArgs, SourceLocation(),
1503                                    DeclarationName());
1504
1505  return Instantiator.TransformTemplateArgument(Input, Output);
1506}
1507