SemaTemplateInstantiate.cpp revision 17e0f407d56748da21050db13ff3a093b1ffdcb7 
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  };
575}
576
577Decl *TemplateInstantiator::TransformDecl(Decl *D) {
578  if (!D)
579    return 0;
580
581  if (TemplateTemplateParmDecl *TTP = dyn_cast<TemplateTemplateParmDecl>(D)) {
582    if (TTP->getDepth() < TemplateArgs.getNumLevels()) {
583      // If the corresponding template argument is NULL or non-existent, it's
584      // because we are performing instantiation from explicitly-specified
585      // template arguments in a function template, but there were some
586      // arguments left unspecified.
587      if (!TemplateArgs.hasTemplateArgument(TTP->getDepth(),
588                                            TTP->getPosition()))
589        return D;
590
591      TemplateName Template
592        = TemplateArgs(TTP->getDepth(), TTP->getPosition()).getAsTemplate();
593      assert(!Template.isNull() && Template.getAsTemplateDecl() &&
594             "Wrong kind of template template argument");
595      return Template.getAsTemplateDecl();
596    }
597
598    // Fall through to find the instantiated declaration for this template
599    // template parameter.
600  }
601
602  return SemaRef.FindInstantiatedDecl(cast<NamedDecl>(D), TemplateArgs);
603}
604
605Decl *TemplateInstantiator::TransformDefinition(Decl *D) {
606  Decl *Inst = getSema().SubstDecl(D, getSema().CurContext, TemplateArgs);
607  if (!Inst)
608    return 0;
609
610  getSema().CurrentInstantiationScope->InstantiatedLocal(D, Inst);
611  return Inst;
612}
613
614NamedDecl *
615TemplateInstantiator::TransformFirstQualifierInScope(NamedDecl *D,
616                                                     SourceLocation Loc) {
617  // If the first part of the nested-name-specifier was a template type
618  // parameter, instantiate that type parameter down to a tag type.
619  if (TemplateTypeParmDecl *TTPD = dyn_cast_or_null<TemplateTypeParmDecl>(D)) {
620    const TemplateTypeParmType *TTP
621      = cast<TemplateTypeParmType>(getSema().Context.getTypeDeclType(TTPD));
622    if (TTP->getDepth() < TemplateArgs.getNumLevels()) {
623      QualType T = TemplateArgs(TTP->getDepth(), TTP->getIndex()).getAsType();
624      if (T.isNull())
625        return cast_or_null<NamedDecl>(TransformDecl(D));
626
627      if (const TagType *Tag = T->getAs<TagType>())
628        return Tag->getDecl();
629
630      // The resulting type is not a tag; complain.
631      getSema().Diag(Loc, diag::err_nested_name_spec_non_tag) << T;
632      return 0;
633    }
634  }
635
636  return cast_or_null<NamedDecl>(TransformDecl(D));
637}
638
639VarDecl *
640TemplateInstantiator::RebuildExceptionDecl(VarDecl *ExceptionDecl,
641                                           QualType T,
642                                           TypeSourceInfo *Declarator,
643                                           IdentifierInfo *Name,
644                                           SourceLocation Loc,
645                                           SourceRange TypeRange) {
646  VarDecl *Var = inherited::RebuildExceptionDecl(ExceptionDecl, T, Declarator,
647                                                 Name, Loc, TypeRange);
648  if (Var && !Var->isInvalidDecl())
649    getSema().CurrentInstantiationScope->InstantiatedLocal(ExceptionDecl, Var);
650  return Var;
651}
652
653QualType
654TemplateInstantiator::RebuildElaboratedType(QualType T,
655                                            ElaboratedType::TagKind Tag) {
656  if (const TagType *TT = T->getAs<TagType>()) {
657    TagDecl* TD = TT->getDecl();
658
659    // FIXME: this location is very wrong;  we really need typelocs.
660    SourceLocation TagLocation = TD->getTagKeywordLoc();
661
662    // FIXME: type might be anonymous.
663    IdentifierInfo *Id = TD->getIdentifier();
664
665    // TODO: should we even warn on struct/class mismatches for this?  Seems
666    // like it's likely to produce a lot of spurious errors.
667    if (!SemaRef.isAcceptableTagRedeclaration(TD, Tag, TagLocation, *Id)) {
668      SemaRef.Diag(TagLocation, diag::err_use_with_wrong_tag)
669        << Id
670        << CodeModificationHint::CreateReplacement(SourceRange(TagLocation),
671                                                   TD->getKindName());
672      SemaRef.Diag(TD->getLocation(), diag::note_previous_use);
673    }
674  }
675
676  return TreeTransform<TemplateInstantiator>::RebuildElaboratedType(T, Tag);
677}
678
679Sema::OwningExprResult
680TemplateInstantiator::TransformPredefinedExpr(PredefinedExpr *E) {
681  if (!E->isTypeDependent())
682    return SemaRef.Owned(E->Retain());
683
684  FunctionDecl *currentDecl = getSema().getCurFunctionDecl();
685  assert(currentDecl && "Must have current function declaration when "
686                        "instantiating.");
687
688  PredefinedExpr::IdentType IT = E->getIdentType();
689
690  unsigned Length = PredefinedExpr::ComputeName(IT, currentDecl).length();
691
692  llvm::APInt LengthI(32, Length + 1);
693  QualType ResTy = getSema().Context.CharTy.withConst();
694  ResTy = getSema().Context.getConstantArrayType(ResTy, LengthI,
695                                                 ArrayType::Normal, 0);
696  PredefinedExpr *PE =
697    new (getSema().Context) PredefinedExpr(E->getLocation(), ResTy, IT);
698  return getSema().Owned(PE);
699}
700
701Sema::OwningExprResult
702TemplateInstantiator::TransformTemplateParmRefExpr(DeclRefExpr *E,
703                                               NonTypeTemplateParmDecl *NTTP) {
704  // If the corresponding template argument is NULL or non-existent, it's
705  // because we are performing instantiation from explicitly-specified
706  // template arguments in a function template, but there were some
707  // arguments left unspecified.
708  if (!TemplateArgs.hasTemplateArgument(NTTP->getDepth(),
709                                        NTTP->getPosition()))
710    return SemaRef.Owned(E->Retain());
711
712  const TemplateArgument &Arg = TemplateArgs(NTTP->getDepth(),
713                                             NTTP->getPosition());
714
715  // The template argument itself might be an expression, in which
716  // case we just return that expression.
717  if (Arg.getKind() == TemplateArgument::Expression)
718    return SemaRef.Owned(Arg.getAsExpr()->Retain());
719
720  if (Arg.getKind() == TemplateArgument::Declaration) {
721    ValueDecl *VD = cast<ValueDecl>(Arg.getAsDecl());
722
723    // Find the instantiation of the template argument.  This is
724    // required for nested templates.
725    VD = cast_or_null<ValueDecl>(
726                              getSema().FindInstantiatedDecl(VD, TemplateArgs));
727    if (!VD)
728      return SemaRef.ExprError();
729
730    // Derive the type we want the substituted decl to have.  This had
731    // better be non-dependent, or these checks will have serious problems.
732    QualType TargetType = SemaRef.SubstType(NTTP->getType(), TemplateArgs,
733                                            E->getLocation(),
734                                            DeclarationName());
735    assert(!TargetType.isNull() && "type substitution failed for param type");
736    assert(!TargetType->isDependentType() && "param type still dependent");
737
738    if (VD->getDeclContext()->isRecord() &&
739        (isa<CXXMethodDecl>(VD) || isa<FieldDecl>(VD))) {
740      // If the value is a class member, we might have a pointer-to-member.
741      // Determine whether the non-type template template parameter is of
742      // pointer-to-member type. If so, we need to build an appropriate
743      // expression for a pointer-to-member, since a "normal" DeclRefExpr
744      // would refer to the member itself.
745      if (TargetType->isMemberPointerType()) {
746        QualType ClassType
747          = SemaRef.Context.getTypeDeclType(
748                                        cast<RecordDecl>(VD->getDeclContext()));
749        NestedNameSpecifier *Qualifier
750          = NestedNameSpecifier::Create(SemaRef.Context, 0, false,
751                                        ClassType.getTypePtr());
752        CXXScopeSpec SS;
753        SS.setScopeRep(Qualifier);
754        OwningExprResult RefExpr
755          = SemaRef.BuildDeclRefExpr(VD,
756                                     VD->getType().getNonReferenceType(),
757                                     E->getLocation(),
758                                     &SS);
759        if (RefExpr.isInvalid())
760          return SemaRef.ExprError();
761
762        RefExpr = SemaRef.CreateBuiltinUnaryOp(E->getLocation(),
763                                               UnaryOperator::AddrOf,
764                                               move(RefExpr));
765        assert(!RefExpr.isInvalid() &&
766               SemaRef.Context.hasSameType(((Expr*) RefExpr.get())->getType(),
767                                           TargetType));
768        return move(RefExpr);
769      }
770    }
771
772    QualType T = VD->getType().getNonReferenceType();
773
774    if (TargetType->isPointerType()) {
775      // C++03 [temp.arg.nontype]p5:
776      //  - For a non-type template-parameter of type pointer to
777      //    object, qualification conversions and the array-to-pointer
778      //    conversion are applied.
779      //  - For a non-type template-parameter of type pointer to
780      //    function, only the function-to-pointer conversion is
781      //    applied.
782
783      OwningExprResult RefExpr
784        = SemaRef.BuildDeclRefExpr(VD, T, E->getLocation());
785      if (RefExpr.isInvalid())
786        return SemaRef.ExprError();
787
788      // Decay functions and arrays.
789      Expr *RefE = (Expr *)RefExpr.get();
790      SemaRef.DefaultFunctionArrayConversion(RefE);
791      if (RefE != RefExpr.get()) {
792        RefExpr.release();
793        RefExpr = SemaRef.Owned(RefE);
794      }
795
796      // Qualification conversions.
797      RefExpr.release();
798      SemaRef.ImpCastExprToType(RefE, TargetType.getUnqualifiedType(),
799                                CastExpr::CK_NoOp);
800      return SemaRef.Owned(RefE);
801    }
802
803    // If the non-type template parameter has reference type, qualify the
804    // resulting declaration reference with the extra qualifiers on the
805    // type that the reference refers to.
806    if (const ReferenceType *TargetRef = TargetType->getAs<ReferenceType>())
807      T = SemaRef.Context.getQualifiedType(T,
808                                  TargetRef->getPointeeType().getQualifiers());
809
810    return SemaRef.BuildDeclRefExpr(VD, T, E->getLocation());
811  }
812
813  assert(Arg.getKind() == TemplateArgument::Integral);
814  QualType T = Arg.getIntegralType();
815  if (T->isCharType() || T->isWideCharType())
816    return SemaRef.Owned(new (SemaRef.Context) CharacterLiteral(
817                                              Arg.getAsIntegral()->getZExtValue(),
818                                              T->isWideCharType(),
819                                              T,
820                                              E->getSourceRange().getBegin()));
821  if (T->isBooleanType())
822    return SemaRef.Owned(new (SemaRef.Context) CXXBoolLiteralExpr(
823                                            Arg.getAsIntegral()->getBoolValue(),
824                                            T,
825                                            E->getSourceRange().getBegin()));
826
827  assert(Arg.getAsIntegral()->getBitWidth() == SemaRef.Context.getIntWidth(T));
828  return SemaRef.Owned(new (SemaRef.Context) IntegerLiteral(
829                                                *Arg.getAsIntegral(),
830                                                T,
831                                                E->getSourceRange().getBegin()));
832}
833
834
835Sema::OwningExprResult
836TemplateInstantiator::TransformDeclRefExpr(DeclRefExpr *E) {
837  NamedDecl *D = E->getDecl();
838  if (NonTypeTemplateParmDecl *NTTP = dyn_cast<NonTypeTemplateParmDecl>(D)) {
839    if (NTTP->getDepth() < TemplateArgs.getNumLevels())
840      return TransformTemplateParmRefExpr(E, NTTP);
841
842    // We have a non-type template parameter that isn't fully substituted;
843    // FindInstantiatedDecl will find it in the local instantiation scope.
844  }
845
846  return TreeTransform<TemplateInstantiator>::TransformDeclRefExpr(E);
847}
848
849Sema::OwningExprResult TemplateInstantiator::TransformCXXDefaultArgExpr(
850    CXXDefaultArgExpr *E) {
851  assert(!cast<FunctionDecl>(E->getParam()->getDeclContext())->
852             getDescribedFunctionTemplate() &&
853         "Default arg expressions are never formed in dependent cases.");
854  return SemaRef.BuildCXXDefaultArgExpr(E->getUsedLocation(),
855                           cast<FunctionDecl>(E->getParam()->getDeclContext()),
856                                        E->getParam());
857}
858
859
860QualType
861TemplateInstantiator::TransformTemplateTypeParmType(TypeLocBuilder &TLB,
862                                                TemplateTypeParmTypeLoc TL) {
863  TemplateTypeParmType *T = TL.getTypePtr();
864  if (T->getDepth() < TemplateArgs.getNumLevels()) {
865    // Replace the template type parameter with its corresponding
866    // template argument.
867
868    // If the corresponding template argument is NULL or doesn't exist, it's
869    // because we are performing instantiation from explicitly-specified
870    // template arguments in a function template class, but there were some
871    // arguments left unspecified.
872    if (!TemplateArgs.hasTemplateArgument(T->getDepth(), T->getIndex())) {
873      TemplateTypeParmTypeLoc NewTL
874        = TLB.push<TemplateTypeParmTypeLoc>(TL.getType());
875      NewTL.setNameLoc(TL.getNameLoc());
876      return TL.getType();
877    }
878
879    assert(TemplateArgs(T->getDepth(), T->getIndex()).getKind()
880             == TemplateArgument::Type &&
881           "Template argument kind mismatch");
882
883    QualType Replacement
884      = TemplateArgs(T->getDepth(), T->getIndex()).getAsType();
885
886    // TODO: only do this uniquing once, at the start of instantiation.
887    QualType Result
888      = getSema().Context.getSubstTemplateTypeParmType(T, Replacement);
889    SubstTemplateTypeParmTypeLoc NewTL
890      = TLB.push<SubstTemplateTypeParmTypeLoc>(Result);
891    NewTL.setNameLoc(TL.getNameLoc());
892    return Result;
893  }
894
895  // The template type parameter comes from an inner template (e.g.,
896  // the template parameter list of a member template inside the
897  // template we are instantiating). Create a new template type
898  // parameter with the template "level" reduced by one.
899  QualType Result
900    = getSema().Context.getTemplateTypeParmType(T->getDepth()
901                                                 - TemplateArgs.getNumLevels(),
902                                                T->getIndex(),
903                                                T->isParameterPack(),
904                                                T->getName());
905  TemplateTypeParmTypeLoc NewTL = TLB.push<TemplateTypeParmTypeLoc>(Result);
906  NewTL.setNameLoc(TL.getNameLoc());
907  return Result;
908}
909
910/// \brief Perform substitution on the type T with a given set of template
911/// arguments.
912///
913/// This routine substitutes the given template arguments into the
914/// type T and produces the instantiated type.
915///
916/// \param T the type into which the template arguments will be
917/// substituted. If this type is not dependent, it will be returned
918/// immediately.
919///
920/// \param TemplateArgs the template arguments that will be
921/// substituted for the top-level template parameters within T.
922///
923/// \param Loc the location in the source code where this substitution
924/// is being performed. It will typically be the location of the
925/// declarator (if we're instantiating the type of some declaration)
926/// or the location of the type in the source code (if, e.g., we're
927/// instantiating the type of a cast expression).
928///
929/// \param Entity the name of the entity associated with a declaration
930/// being instantiated (if any). May be empty to indicate that there
931/// is no such entity (if, e.g., this is a type that occurs as part of
932/// a cast expression) or that the entity has no name (e.g., an
933/// unnamed function parameter).
934///
935/// \returns If the instantiation succeeds, the instantiated
936/// type. Otherwise, produces diagnostics and returns a NULL type.
937TypeSourceInfo *Sema::SubstType(TypeSourceInfo *T,
938                                const MultiLevelTemplateArgumentList &Args,
939                                SourceLocation Loc,
940                                DeclarationName Entity) {
941  assert(!ActiveTemplateInstantiations.empty() &&
942         "Cannot perform an instantiation without some context on the "
943         "instantiation stack");
944
945  if (!T->getType()->isDependentType())
946    return T;
947
948  TemplateInstantiator Instantiator(*this, Args, Loc, Entity);
949  return Instantiator.TransformType(T);
950}
951
952/// Deprecated form of the above.
953QualType Sema::SubstType(QualType T,
954                         const MultiLevelTemplateArgumentList &TemplateArgs,
955                         SourceLocation Loc, DeclarationName Entity) {
956  assert(!ActiveTemplateInstantiations.empty() &&
957         "Cannot perform an instantiation without some context on the "
958         "instantiation stack");
959
960  // If T is not a dependent type, there is nothing to do.
961  if (!T->isDependentType())
962    return T;
963
964  TemplateInstantiator Instantiator(*this, TemplateArgs, Loc, Entity);
965  return Instantiator.TransformType(T);
966}
967
968/// \brief Perform substitution on the base class specifiers of the
969/// given class template specialization.
970///
971/// Produces a diagnostic and returns true on error, returns false and
972/// attaches the instantiated base classes to the class template
973/// specialization if successful.
974bool
975Sema::SubstBaseSpecifiers(CXXRecordDecl *Instantiation,
976                          CXXRecordDecl *Pattern,
977                          const MultiLevelTemplateArgumentList &TemplateArgs) {
978  bool Invalid = false;
979  llvm::SmallVector<CXXBaseSpecifier*, 4> InstantiatedBases;
980  for (ClassTemplateSpecializationDecl::base_class_iterator
981         Base = Pattern->bases_begin(), BaseEnd = Pattern->bases_end();
982       Base != BaseEnd; ++Base) {
983    if (!Base->getType()->isDependentType()) {
984      const CXXRecordDecl *BaseDecl =
985        cast<CXXRecordDecl>(Base->getType()->getAs<RecordType>()->getDecl());
986
987      // Make sure to set the attributes from the base.
988      SetClassDeclAttributesFromBase(Instantiation, BaseDecl,
989                                     Base->isVirtual());
990
991      InstantiatedBases.push_back(new (Context) CXXBaseSpecifier(*Base));
992      continue;
993    }
994
995    QualType BaseType = SubstType(Base->getType(),
996                                  TemplateArgs,
997                                  Base->getSourceRange().getBegin(),
998                                  DeclarationName());
999    if (BaseType.isNull()) {
1000      Invalid = true;
1001      continue;
1002    }
1003
1004    if (CXXBaseSpecifier *InstantiatedBase
1005          = CheckBaseSpecifier(Instantiation,
1006                               Base->getSourceRange(),
1007                               Base->isVirtual(),
1008                               Base->getAccessSpecifierAsWritten(),
1009                               BaseType,
1010                               /*FIXME: Not totally accurate */
1011                               Base->getSourceRange().getBegin()))
1012      InstantiatedBases.push_back(InstantiatedBase);
1013    else
1014      Invalid = true;
1015  }
1016
1017  if (!Invalid &&
1018      AttachBaseSpecifiers(Instantiation, InstantiatedBases.data(),
1019                           InstantiatedBases.size()))
1020    Invalid = true;
1021
1022  return Invalid;
1023}
1024
1025/// \brief Instantiate the definition of a class from a given pattern.
1026///
1027/// \param PointOfInstantiation The point of instantiation within the
1028/// source code.
1029///
1030/// \param Instantiation is the declaration whose definition is being
1031/// instantiated. This will be either a class template specialization
1032/// or a member class of a class template specialization.
1033///
1034/// \param Pattern is the pattern from which the instantiation
1035/// occurs. This will be either the declaration of a class template or
1036/// the declaration of a member class of a class template.
1037///
1038/// \param TemplateArgs The template arguments to be substituted into
1039/// the pattern.
1040///
1041/// \param TSK the kind of implicit or explicit instantiation to perform.
1042///
1043/// \param Complain whether to complain if the class cannot be instantiated due
1044/// to the lack of a definition.
1045///
1046/// \returns true if an error occurred, false otherwise.
1047bool
1048Sema::InstantiateClass(SourceLocation PointOfInstantiation,
1049                       CXXRecordDecl *Instantiation, CXXRecordDecl *Pattern,
1050                       const MultiLevelTemplateArgumentList &TemplateArgs,
1051                       TemplateSpecializationKind TSK,
1052                       bool Complain) {
1053  bool Invalid = false;
1054
1055  CXXRecordDecl *PatternDef
1056    = cast_or_null<CXXRecordDecl>(Pattern->getDefinition());
1057  if (!PatternDef) {
1058    if (!Complain) {
1059      // Say nothing
1060    } else if (Pattern == Instantiation->getInstantiatedFromMemberClass()) {
1061      Diag(PointOfInstantiation,
1062           diag::err_implicit_instantiate_member_undefined)
1063        << Context.getTypeDeclType(Instantiation);
1064      Diag(Pattern->getLocation(), diag::note_member_of_template_here);
1065    } else {
1066      Diag(PointOfInstantiation, diag::err_template_instantiate_undefined)
1067        << (TSK != TSK_ImplicitInstantiation)
1068        << Context.getTypeDeclType(Instantiation);
1069      Diag(Pattern->getLocation(), diag::note_template_decl_here);
1070    }
1071    return true;
1072  }
1073  Pattern = PatternDef;
1074
1075  // \brief Record the point of instantiation.
1076  if (MemberSpecializationInfo *MSInfo
1077        = Instantiation->getMemberSpecializationInfo()) {
1078    MSInfo->setTemplateSpecializationKind(TSK);
1079    MSInfo->setPointOfInstantiation(PointOfInstantiation);
1080  } else if (ClassTemplateSpecializationDecl *Spec
1081               = dyn_cast<ClassTemplateSpecializationDecl>(Instantiation)) {
1082    Spec->setTemplateSpecializationKind(TSK);
1083    Spec->setPointOfInstantiation(PointOfInstantiation);
1084  }
1085
1086  InstantiatingTemplate Inst(*this, PointOfInstantiation, Instantiation);
1087  if (Inst)
1088    return true;
1089
1090  // Enter the scope of this instantiation. We don't use
1091  // PushDeclContext because we don't have a scope.
1092  DeclContext *PreviousContext = CurContext;
1093  CurContext = Instantiation;
1094
1095  // Start the definition of this instantiation.
1096  Instantiation->startDefinition();
1097
1098  // Do substitution on the base class specifiers.
1099  if (SubstBaseSpecifiers(Instantiation, Pattern, TemplateArgs))
1100    Invalid = true;
1101
1102  llvm::SmallVector<DeclPtrTy, 4> Fields;
1103  for (RecordDecl::decl_iterator Member = Pattern->decls_begin(),
1104         MemberEnd = Pattern->decls_end();
1105       Member != MemberEnd; ++Member) {
1106    Decl *NewMember = SubstDecl(*Member, Instantiation, TemplateArgs);
1107    if (NewMember) {
1108      if (FieldDecl *Field = dyn_cast<FieldDecl>(NewMember))
1109        Fields.push_back(DeclPtrTy::make(Field));
1110      else if (NewMember->isInvalidDecl())
1111        Invalid = true;
1112    } else {
1113      // FIXME: Eventually, a NULL return will mean that one of the
1114      // instantiations was a semantic disaster, and we'll want to set Invalid =
1115      // true. For now, we expect to skip some members that we can't yet handle.
1116    }
1117  }
1118
1119  // Finish checking fields.
1120  ActOnFields(0, Instantiation->getLocation(), DeclPtrTy::make(Instantiation),
1121              Fields.data(), Fields.size(), SourceLocation(), SourceLocation(),
1122              0);
1123  CheckCompletedCXXClass(Instantiation);
1124  if (Instantiation->isInvalidDecl())
1125    Invalid = true;
1126
1127  // Exit the scope of this instantiation.
1128  CurContext = PreviousContext;
1129
1130  // If this is a polymorphic C++ class without a key function, we'll
1131  // have to mark all of the virtual members to allow emission of a vtable
1132  // in this translation unit.
1133  if (Instantiation->isDynamicClass() &&
1134      !Context.getKeyFunction(Instantiation)) {
1135    // Local classes need to have their methods instantiated immediately in
1136    // order to have the correct instantiation scope.
1137    if (Instantiation->isLocalClass()) {
1138      MarkVirtualMembersReferenced(PointOfInstantiation,
1139                                   Instantiation);
1140    } else {
1141      ClassesWithUnmarkedVirtualMembers.push_back(std::make_pair(Instantiation,
1142                                                       PointOfInstantiation));
1143    }
1144  }
1145
1146  if (!Invalid)
1147    Consumer.HandleTagDeclDefinition(Instantiation);
1148
1149  return Invalid;
1150}
1151
1152bool
1153Sema::InstantiateClassTemplateSpecialization(
1154                           SourceLocation PointOfInstantiation,
1155                           ClassTemplateSpecializationDecl *ClassTemplateSpec,
1156                           TemplateSpecializationKind TSK,
1157                           bool Complain) {
1158  // Perform the actual instantiation on the canonical declaration.
1159  ClassTemplateSpec = cast<ClassTemplateSpecializationDecl>(
1160                                         ClassTemplateSpec->getCanonicalDecl());
1161
1162  // Check whether we have already instantiated or specialized this class
1163  // template specialization.
1164  if (ClassTemplateSpec->getSpecializationKind() != TSK_Undeclared) {
1165    if (ClassTemplateSpec->getSpecializationKind() ==
1166          TSK_ExplicitInstantiationDeclaration &&
1167        TSK == TSK_ExplicitInstantiationDefinition) {
1168      // An explicit instantiation definition follows an explicit instantiation
1169      // declaration (C++0x [temp.explicit]p10); go ahead and perform the
1170      // explicit instantiation.
1171      ClassTemplateSpec->setSpecializationKind(TSK);
1172      return false;
1173    }
1174
1175    // We can only instantiate something that hasn't already been
1176    // instantiated or specialized. Fail without any diagnostics: our
1177    // caller will provide an error message.
1178    return true;
1179  }
1180
1181  if (ClassTemplateSpec->isInvalidDecl())
1182    return true;
1183
1184  ClassTemplateDecl *Template = ClassTemplateSpec->getSpecializedTemplate();
1185  CXXRecordDecl *Pattern = 0;
1186
1187  // C++ [temp.class.spec.match]p1:
1188  //   When a class template is used in a context that requires an
1189  //   instantiation of the class, it is necessary to determine
1190  //   whether the instantiation is to be generated using the primary
1191  //   template or one of the partial specializations. This is done by
1192  //   matching the template arguments of the class template
1193  //   specialization with the template argument lists of the partial
1194  //   specializations.
1195  typedef std::pair<ClassTemplatePartialSpecializationDecl *,
1196                    TemplateArgumentList *> MatchResult;
1197  llvm::SmallVector<MatchResult, 4> Matched;
1198  for (llvm::FoldingSet<ClassTemplatePartialSpecializationDecl>::iterator
1199         Partial = Template->getPartialSpecializations().begin(),
1200         PartialEnd = Template->getPartialSpecializations().end();
1201       Partial != PartialEnd;
1202       ++Partial) {
1203    TemplateDeductionInfo Info(Context, PointOfInstantiation);
1204    if (TemplateDeductionResult Result
1205          = DeduceTemplateArguments(&*Partial,
1206                                    ClassTemplateSpec->getTemplateArgs(),
1207                                    Info)) {
1208      // FIXME: Store the failed-deduction information for use in
1209      // diagnostics, later.
1210      (void)Result;
1211    } else {
1212      Matched.push_back(std::make_pair(&*Partial, Info.take()));
1213    }
1214  }
1215
1216  if (Matched.size() >= 1) {
1217    llvm::SmallVector<MatchResult, 4>::iterator Best = Matched.begin();
1218    if (Matched.size() == 1) {
1219      //   -- If exactly one matching specialization is found, the
1220      //      instantiation is generated from that specialization.
1221      // We don't need to do anything for this.
1222    } else {
1223      //   -- If more than one matching specialization is found, the
1224      //      partial order rules (14.5.4.2) are used to determine
1225      //      whether one of the specializations is more specialized
1226      //      than the others. If none of the specializations is more
1227      //      specialized than all of the other matching
1228      //      specializations, then the use of the class template is
1229      //      ambiguous and the program is ill-formed.
1230      for (llvm::SmallVector<MatchResult, 4>::iterator P = Best + 1,
1231                                                    PEnd = Matched.end();
1232           P != PEnd; ++P) {
1233        if (getMoreSpecializedPartialSpecialization(P->first, Best->first,
1234                                                    PointOfInstantiation)
1235              == P->first)
1236          Best = P;
1237      }
1238
1239      // Determine if the best partial specialization is more specialized than
1240      // the others.
1241      bool Ambiguous = false;
1242      for (llvm::SmallVector<MatchResult, 4>::iterator P = Matched.begin(),
1243                                                    PEnd = Matched.end();
1244           P != PEnd; ++P) {
1245        if (P != Best &&
1246            getMoreSpecializedPartialSpecialization(P->first, Best->first,
1247                                                    PointOfInstantiation)
1248              != Best->first) {
1249          Ambiguous = true;
1250          break;
1251        }
1252      }
1253
1254      if (Ambiguous) {
1255        // Partial ordering did not produce a clear winner. Complain.
1256        ClassTemplateSpec->setInvalidDecl();
1257        Diag(PointOfInstantiation, diag::err_partial_spec_ordering_ambiguous)
1258          << ClassTemplateSpec;
1259
1260        // Print the matching partial specializations.
1261        for (llvm::SmallVector<MatchResult, 4>::iterator P = Matched.begin(),
1262                                                      PEnd = Matched.end();
1263             P != PEnd; ++P)
1264          Diag(P->first->getLocation(), diag::note_partial_spec_match)
1265            << getTemplateArgumentBindingsText(P->first->getTemplateParameters(),
1266                                               *P->second);
1267
1268        return true;
1269      }
1270    }
1271
1272    // Instantiate using the best class template partial specialization.
1273    ClassTemplatePartialSpecializationDecl *OrigPartialSpec = Best->first;
1274    while (OrigPartialSpec->getInstantiatedFromMember()) {
1275      // If we've found an explicit specialization of this class template,
1276      // stop here and use that as the pattern.
1277      if (OrigPartialSpec->isMemberSpecialization())
1278        break;
1279
1280      OrigPartialSpec = OrigPartialSpec->getInstantiatedFromMember();
1281    }
1282
1283    Pattern = OrigPartialSpec;
1284    ClassTemplateSpec->setInstantiationOf(Best->first, Best->second);
1285  } else {
1286    //   -- If no matches are found, the instantiation is generated
1287    //      from the primary template.
1288    ClassTemplateDecl *OrigTemplate = Template;
1289    while (OrigTemplate->getInstantiatedFromMemberTemplate()) {
1290      // If we've found an explicit specialization of this class template,
1291      // stop here and use that as the pattern.
1292      if (OrigTemplate->isMemberSpecialization())
1293        break;
1294
1295      OrigTemplate = OrigTemplate->getInstantiatedFromMemberTemplate();
1296    }
1297
1298    Pattern = OrigTemplate->getTemplatedDecl();
1299  }
1300
1301  bool Result = InstantiateClass(PointOfInstantiation, ClassTemplateSpec,
1302                                 Pattern,
1303                                getTemplateInstantiationArgs(ClassTemplateSpec),
1304                                 TSK,
1305                                 Complain);
1306
1307  for (unsigned I = 0, N = Matched.size(); I != N; ++I) {
1308    // FIXME: Implement TemplateArgumentList::Destroy!
1309    //    if (Matched[I].first != Pattern)
1310    //      Matched[I].second->Destroy(Context);
1311  }
1312
1313  return Result;
1314}
1315
1316/// \brief Instantiates the definitions of all of the member
1317/// of the given class, which is an instantiation of a class template
1318/// or a member class of a template.
1319void
1320Sema::InstantiateClassMembers(SourceLocation PointOfInstantiation,
1321                              CXXRecordDecl *Instantiation,
1322                        const MultiLevelTemplateArgumentList &TemplateArgs,
1323                              TemplateSpecializationKind TSK) {
1324  for (DeclContext::decl_iterator D = Instantiation->decls_begin(),
1325                               DEnd = Instantiation->decls_end();
1326       D != DEnd; ++D) {
1327    bool SuppressNew = false;
1328    if (FunctionDecl *Function = dyn_cast<FunctionDecl>(*D)) {
1329      if (FunctionDecl *Pattern
1330            = Function->getInstantiatedFromMemberFunction()) {
1331        MemberSpecializationInfo *MSInfo
1332          = Function->getMemberSpecializationInfo();
1333        assert(MSInfo && "No member specialization information?");
1334        if (CheckSpecializationInstantiationRedecl(PointOfInstantiation, TSK,
1335                                                   Function,
1336                                        MSInfo->getTemplateSpecializationKind(),
1337                                              MSInfo->getPointOfInstantiation(),
1338                                                   SuppressNew) ||
1339            SuppressNew)
1340          continue;
1341
1342        if (Function->getBody())
1343          continue;
1344
1345        if (TSK == TSK_ExplicitInstantiationDefinition) {
1346          // C++0x [temp.explicit]p8:
1347          //   An explicit instantiation definition that names a class template
1348          //   specialization explicitly instantiates the class template
1349          //   specialization and is only an explicit instantiation definition
1350          //   of members whose definition is visible at the point of
1351          //   instantiation.
1352          if (!Pattern->getBody())
1353            continue;
1354
1355          Function->setTemplateSpecializationKind(TSK, PointOfInstantiation);
1356
1357          InstantiateFunctionDefinition(PointOfInstantiation, Function);
1358        } else {
1359          Function->setTemplateSpecializationKind(TSK, PointOfInstantiation);
1360        }
1361      }
1362    } else if (VarDecl *Var = dyn_cast<VarDecl>(*D)) {
1363      if (Var->isStaticDataMember()) {
1364        MemberSpecializationInfo *MSInfo = Var->getMemberSpecializationInfo();
1365        assert(MSInfo && "No member specialization information?");
1366        if (CheckSpecializationInstantiationRedecl(PointOfInstantiation, TSK,
1367                                                   Var,
1368                                        MSInfo->getTemplateSpecializationKind(),
1369                                              MSInfo->getPointOfInstantiation(),
1370                                                   SuppressNew) ||
1371            SuppressNew)
1372          continue;
1373
1374        if (TSK == TSK_ExplicitInstantiationDefinition) {
1375          // C++0x [temp.explicit]p8:
1376          //   An explicit instantiation definition that names a class template
1377          //   specialization explicitly instantiates the class template
1378          //   specialization and is only an explicit instantiation definition
1379          //   of members whose definition is visible at the point of
1380          //   instantiation.
1381          if (!Var->getInstantiatedFromStaticDataMember()
1382                                                     ->getOutOfLineDefinition())
1383            continue;
1384
1385          Var->setTemplateSpecializationKind(TSK, PointOfInstantiation);
1386          InstantiateStaticDataMemberDefinition(PointOfInstantiation, Var);
1387        } else {
1388          Var->setTemplateSpecializationKind(TSK, PointOfInstantiation);
1389        }
1390      }
1391    } else if (CXXRecordDecl *Record = dyn_cast<CXXRecordDecl>(*D)) {
1392      if (Record->isInjectedClassName())
1393        continue;
1394
1395      MemberSpecializationInfo *MSInfo = Record->getMemberSpecializationInfo();
1396      assert(MSInfo && "No member specialization information?");
1397      if (CheckSpecializationInstantiationRedecl(PointOfInstantiation, TSK,
1398                                                 Record,
1399                                        MSInfo->getTemplateSpecializationKind(),
1400                                              MSInfo->getPointOfInstantiation(),
1401                                                 SuppressNew) ||
1402          SuppressNew)
1403        continue;
1404
1405      CXXRecordDecl *Pattern = Record->getInstantiatedFromMemberClass();
1406      assert(Pattern && "Missing instantiated-from-template information");
1407
1408      if (!Record->getDefinition()) {
1409        if (!Pattern->getDefinition()) {
1410          // C++0x [temp.explicit]p8:
1411          //   An explicit instantiation definition that names a class template
1412          //   specialization explicitly instantiates the class template
1413          //   specialization and is only an explicit instantiation definition
1414          //   of members whose definition is visible at the point of
1415          //   instantiation.
1416          if (TSK == TSK_ExplicitInstantiationDeclaration) {
1417            MSInfo->setTemplateSpecializationKind(TSK);
1418            MSInfo->setPointOfInstantiation(PointOfInstantiation);
1419          }
1420
1421          continue;
1422        }
1423
1424        InstantiateClass(PointOfInstantiation, Record, Pattern,
1425                         TemplateArgs,
1426                         TSK);
1427      }
1428
1429      Pattern = cast_or_null<CXXRecordDecl>(Record->getDefinition());
1430      if (Pattern)
1431        InstantiateClassMembers(PointOfInstantiation, Pattern, TemplateArgs,
1432                                TSK);
1433    }
1434  }
1435}
1436
1437/// \brief Instantiate the definitions of all of the members of the
1438/// given class template specialization, which was named as part of an
1439/// explicit instantiation.
1440void
1441Sema::InstantiateClassTemplateSpecializationMembers(
1442                                           SourceLocation PointOfInstantiation,
1443                            ClassTemplateSpecializationDecl *ClassTemplateSpec,
1444                                               TemplateSpecializationKind TSK) {
1445  // C++0x [temp.explicit]p7:
1446  //   An explicit instantiation that names a class template
1447  //   specialization is an explicit instantion of the same kind
1448  //   (declaration or definition) of each of its members (not
1449  //   including members inherited from base classes) that has not
1450  //   been previously explicitly specialized in the translation unit
1451  //   containing the explicit instantiation, except as described
1452  //   below.
1453  InstantiateClassMembers(PointOfInstantiation, ClassTemplateSpec,
1454                          getTemplateInstantiationArgs(ClassTemplateSpec),
1455                          TSK);
1456}
1457
1458Sema::OwningStmtResult
1459Sema::SubstStmt(Stmt *S, const MultiLevelTemplateArgumentList &TemplateArgs) {
1460  if (!S)
1461    return Owned(S);
1462
1463  TemplateInstantiator Instantiator(*this, TemplateArgs,
1464                                    SourceLocation(),
1465                                    DeclarationName());
1466  return Instantiator.TransformStmt(S);
1467}
1468
1469Sema::OwningExprResult
1470Sema::SubstExpr(Expr *E, const MultiLevelTemplateArgumentList &TemplateArgs) {
1471  if (!E)
1472    return Owned(E);
1473
1474  TemplateInstantiator Instantiator(*this, TemplateArgs,
1475                                    SourceLocation(),
1476                                    DeclarationName());
1477  return Instantiator.TransformExpr(E);
1478}
1479
1480/// \brief Do template substitution on a nested-name-specifier.
1481NestedNameSpecifier *
1482Sema::SubstNestedNameSpecifier(NestedNameSpecifier *NNS,
1483                               SourceRange Range,
1484                         const MultiLevelTemplateArgumentList &TemplateArgs) {
1485  TemplateInstantiator Instantiator(*this, TemplateArgs, Range.getBegin(),
1486                                    DeclarationName());
1487  return Instantiator.TransformNestedNameSpecifier(NNS, Range);
1488}
1489
1490TemplateName
1491Sema::SubstTemplateName(TemplateName Name, SourceLocation Loc,
1492                        const MultiLevelTemplateArgumentList &TemplateArgs) {
1493  TemplateInstantiator Instantiator(*this, TemplateArgs, Loc,
1494                                    DeclarationName());
1495  return Instantiator.TransformTemplateName(Name);
1496}
1497
1498bool Sema::Subst(const TemplateArgumentLoc &Input, TemplateArgumentLoc &Output,
1499                 const MultiLevelTemplateArgumentList &TemplateArgs) {
1500  TemplateInstantiator Instantiator(*this, TemplateArgs, SourceLocation(),
1501                                    DeclarationName());
1502
1503  return Instantiator.TransformTemplateArgument(Input, Output);
1504}
1505