SemaTemplateInstantiate.cpp revision 525f96c0ef39f91abd26b1b4584ba1814e7ebc28 
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
568    /// \brief Transforms a template type parameter type by performing
569    /// substitution of the corresponding template type argument.
570    QualType TransformTemplateTypeParmType(TypeLocBuilder &TLB,
571                                           TemplateTypeParmTypeLoc TL);
572  };
573}
574
575Decl *TemplateInstantiator::TransformDecl(Decl *D) {
576  if (!D)
577    return 0;
578
579  if (TemplateTemplateParmDecl *TTP = dyn_cast<TemplateTemplateParmDecl>(D)) {
580    if (TTP->getDepth() < TemplateArgs.getNumLevels()) {
581      TemplateName Template
582        = TemplateArgs(TTP->getDepth(), TTP->getPosition()).getAsTemplate();
583      assert(!Template.isNull() && Template.getAsTemplateDecl() &&
584             "Wrong kind of template template argument");
585      return Template.getAsTemplateDecl();
586    }
587
588    // If the corresponding template argument is NULL or non-existent, it's
589    // because we are performing instantiation from explicitly-specified
590    // template arguments in a function template, but there were some
591    // arguments left unspecified.
592    if (!TemplateArgs.hasTemplateArgument(TTP->getDepth(),
593                                          TTP->getPosition()))
594      return D;
595
596    // Fall through to find the instantiated declaration for this template
597    // template parameter.
598  }
599
600  return SemaRef.FindInstantiatedDecl(cast<NamedDecl>(D), TemplateArgs);
601}
602
603Decl *TemplateInstantiator::TransformDefinition(Decl *D) {
604  Decl *Inst = getSema().SubstDecl(D, getSema().CurContext, TemplateArgs);
605  if (!Inst)
606    return 0;
607
608  getSema().CurrentInstantiationScope->InstantiatedLocal(D, Inst);
609  return Inst;
610}
611
612NamedDecl *
613TemplateInstantiator::TransformFirstQualifierInScope(NamedDecl *D,
614                                                     SourceLocation Loc) {
615  // If the first part of the nested-name-specifier was a template type
616  // parameter, instantiate that type parameter down to a tag type.
617  if (TemplateTypeParmDecl *TTPD = dyn_cast_or_null<TemplateTypeParmDecl>(D)) {
618    const TemplateTypeParmType *TTP
619      = cast<TemplateTypeParmType>(getSema().Context.getTypeDeclType(TTPD));
620    if (TTP->getDepth() < TemplateArgs.getNumLevels()) {
621      QualType T = TemplateArgs(TTP->getDepth(), TTP->getIndex()).getAsType();
622      if (T.isNull())
623        return cast_or_null<NamedDecl>(TransformDecl(D));
624
625      if (const TagType *Tag = T->getAs<TagType>())
626        return Tag->getDecl();
627
628      // The resulting type is not a tag; complain.
629      getSema().Diag(Loc, diag::err_nested_name_spec_non_tag) << T;
630      return 0;
631    }
632  }
633
634  return cast_or_null<NamedDecl>(TransformDecl(D));
635}
636
637VarDecl *
638TemplateInstantiator::RebuildExceptionDecl(VarDecl *ExceptionDecl,
639                                           QualType T,
640                                           TypeSourceInfo *Declarator,
641                                           IdentifierInfo *Name,
642                                           SourceLocation Loc,
643                                           SourceRange TypeRange) {
644  VarDecl *Var = inherited::RebuildExceptionDecl(ExceptionDecl, T, Declarator,
645                                                 Name, Loc, TypeRange);
646  if (Var && !Var->isInvalidDecl())
647    getSema().CurrentInstantiationScope->InstantiatedLocal(ExceptionDecl, Var);
648  return Var;
649}
650
651QualType
652TemplateInstantiator::RebuildElaboratedType(QualType T,
653                                            ElaboratedType::TagKind Tag) {
654  if (const TagType *TT = T->getAs<TagType>()) {
655    TagDecl* TD = TT->getDecl();
656
657    // FIXME: this location is very wrong;  we really need typelocs.
658    SourceLocation TagLocation = TD->getTagKeywordLoc();
659
660    // FIXME: type might be anonymous.
661    IdentifierInfo *Id = TD->getIdentifier();
662
663    // TODO: should we even warn on struct/class mismatches for this?  Seems
664    // like it's likely to produce a lot of spurious errors.
665    if (!SemaRef.isAcceptableTagRedeclaration(TD, Tag, TagLocation, *Id)) {
666      SemaRef.Diag(TagLocation, diag::err_use_with_wrong_tag)
667        << Id
668        << CodeModificationHint::CreateReplacement(SourceRange(TagLocation),
669                                                   TD->getKindName());
670      SemaRef.Diag(TD->getLocation(), diag::note_previous_use);
671    }
672  }
673
674  return TreeTransform<TemplateInstantiator>::RebuildElaboratedType(T, Tag);
675}
676
677Sema::OwningExprResult
678TemplateInstantiator::TransformPredefinedExpr(PredefinedExpr *E) {
679  if (!E->isTypeDependent())
680    return SemaRef.Owned(E->Retain());
681
682  FunctionDecl *currentDecl = getSema().getCurFunctionDecl();
683  assert(currentDecl && "Must have current function declaration when "
684                        "instantiating.");
685
686  PredefinedExpr::IdentType IT = E->getIdentType();
687
688  unsigned Length =
689    PredefinedExpr::ComputeName(getSema().Context, IT, currentDecl).length();
690
691  llvm::APInt LengthI(32, Length + 1);
692  QualType ResTy = getSema().Context.CharTy.withConst();
693  ResTy = getSema().Context.getConstantArrayType(ResTy, LengthI,
694                                                 ArrayType::Normal, 0);
695  PredefinedExpr *PE =
696    new (getSema().Context) PredefinedExpr(E->getLocation(), ResTy, IT);
697  return getSema().Owned(PE);
698}
699
700Sema::OwningExprResult
701TemplateInstantiator::TransformDeclRefExpr(DeclRefExpr *E) {
702  // FIXME: Clean this up a bit
703  NamedDecl *D = E->getDecl();
704  if (NonTypeTemplateParmDecl *NTTP = dyn_cast<NonTypeTemplateParmDecl>(D)) {
705    if (NTTP->getDepth() < TemplateArgs.getNumLevels()) {
706      // If the corresponding template argument is NULL or non-existent, it's
707      // because we are performing instantiation from explicitly-specified
708      // template arguments in a function template, but there were some
709      // arguments left unspecified.
710      if (!TemplateArgs.hasTemplateArgument(NTTP->getDepth(),
711                                            NTTP->getPosition()))
712        return SemaRef.Owned(E->Retain());
713
714      const TemplateArgument &Arg = TemplateArgs(NTTP->getDepth(),
715                                                 NTTP->getPosition());
716
717      // The template argument itself might be an expression, in which
718      // case we just return that expression.
719      if (Arg.getKind() == TemplateArgument::Expression)
720        return SemaRef.Owned(Arg.getAsExpr()->Retain());
721
722      if (Arg.getKind() == TemplateArgument::Declaration) {
723        ValueDecl *VD = cast<ValueDecl>(Arg.getAsDecl());
724
725        VD = cast_or_null<ValueDecl>(
726                              getSema().FindInstantiatedDecl(VD, TemplateArgs));
727        if (!VD)
728          return SemaRef.ExprError();
729
730        if (VD->getDeclContext()->isRecord() &&
731            (isa<CXXMethodDecl>(VD) || isa<FieldDecl>(VD))) {
732          // If the value is a class member, we might have a pointer-to-member.
733          // Determine whether the non-type template template parameter is of
734          // pointer-to-member type. If so, we need to build an appropriate
735          // expression for a pointer-to-member, since a "normal" DeclRefExpr
736          // would refer to the member itself.
737          if (NTTP->getType()->isMemberPointerType()) {
738            QualType ClassType
739              = SemaRef.Context.getTypeDeclType(
740                                        cast<RecordDecl>(VD->getDeclContext()));
741            NestedNameSpecifier *Qualifier
742              = NestedNameSpecifier::Create(SemaRef.Context, 0, false,
743                                            ClassType.getTypePtr());
744            CXXScopeSpec SS;
745            SS.setScopeRep(Qualifier);
746            OwningExprResult RefExpr
747              = SemaRef.BuildDeclRefExpr(VD,
748                                         VD->getType().getNonReferenceType(),
749                                         E->getLocation(),
750                                         &SS);
751            if (RefExpr.isInvalid())
752              return SemaRef.ExprError();
753
754            return SemaRef.CreateBuiltinUnaryOp(E->getLocation(),
755                                                UnaryOperator::AddrOf,
756                                                move(RefExpr));
757          }
758        }
759        if (NTTP->getType()->isPointerType()) {
760          // If the template argument is expected to be a pointer
761          // type, we may have to decay array/pointer references, take
762          // the address of the argument, or perform cv-qualification
763          // adjustments to get the type of the rvalue right. Do so.
764          OwningExprResult RefExpr
765            = SemaRef.BuildDeclRefExpr(VD, VD->getType().getNonReferenceType(),
766                                       E->getLocation());
767          if (RefExpr.isInvalid())
768            return SemaRef.ExprError();
769
770          // Decay functions and arrays.
771          Expr *RefE = (Expr *)RefExpr.get();
772          SemaRef.DefaultFunctionArrayConversion(RefE);
773          if (RefE != RefExpr.get()) {
774            RefExpr.release();
775            RefExpr = SemaRef.Owned(RefE);
776          }
777
778          // If the unqualified types are different and a a
779          // qualification conversion won't fix them types, we need to
780          // take the address.  FIXME: Should we encode these steps in
781          // the template argument, then replay them here, like a
782          // miniature InitializationSequence?
783          if (!SemaRef.Context.hasSameUnqualifiedType(RefE->getType(),
784                                                      NTTP->getType()) &&
785              !SemaRef.IsQualificationConversion(RefE->getType(),
786                                                 NTTP->getType())) {
787            RefExpr = SemaRef.CreateBuiltinUnaryOp(E->getLocation(),
788                                                   UnaryOperator::AddrOf,
789                                                   move(RefExpr));
790            if (RefExpr.isInvalid())
791              return SemaRef.ExprError();
792
793            RefE = (Expr *)RefExpr.get();
794            assert(SemaRef.IsQualificationConversion(RefE->getType(),
795                                                     NTTP->getType()));
796          }
797
798          // Strip top-level cv-qualifiers off the type.
799          RefExpr.release();
800          SemaRef.ImpCastExprToType(RefE,
801                                    NTTP->getType().getUnqualifiedType(),
802                                    CastExpr::CK_NoOp);
803          return SemaRef.Owned(RefE);
804        }
805
806        return SemaRef.BuildDeclRefExpr(VD, VD->getType().getNonReferenceType(),
807                                        E->getLocation());
808      }
809
810      assert(Arg.getKind() == TemplateArgument::Integral);
811      QualType T = Arg.getIntegralType();
812      if (T->isCharType() || T->isWideCharType())
813        return SemaRef.Owned(new (SemaRef.Context) CharacterLiteral(
814                                              Arg.getAsIntegral()->getZExtValue(),
815                                              T->isWideCharType(),
816                                              T,
817                                              E->getSourceRange().getBegin()));
818      if (T->isBooleanType())
819        return SemaRef.Owned(new (SemaRef.Context) CXXBoolLiteralExpr(
820                                            Arg.getAsIntegral()->getBoolValue(),
821                                            T,
822                                            E->getSourceRange().getBegin()));
823
824      assert(Arg.getAsIntegral()->getBitWidth() == SemaRef.Context.getIntWidth(T));
825      return SemaRef.Owned(new (SemaRef.Context) IntegerLiteral(
826                                                *Arg.getAsIntegral(),
827                                                T,
828                                                E->getSourceRange().getBegin()));
829    }
830
831    // We have a non-type template parameter that isn't fully substituted;
832    // FindInstantiatedDecl will find it in the local instantiation scope.
833  }
834
835  return TreeTransform<TemplateInstantiator>::TransformDeclRefExpr(E);
836}
837
838Sema::OwningExprResult TemplateInstantiator::TransformCXXDefaultArgExpr(
839    CXXDefaultArgExpr *E) {
840  assert(!cast<FunctionDecl>(E->getParam()->getDeclContext())->
841             getDescribedFunctionTemplate() &&
842         "Default arg expressions are never formed in dependent cases.");
843  return SemaRef.BuildCXXDefaultArgExpr(E->getUsedLocation(),
844                           cast<FunctionDecl>(E->getParam()->getDeclContext()),
845                                        E->getParam());
846}
847
848
849QualType
850TemplateInstantiator::TransformTemplateTypeParmType(TypeLocBuilder &TLB,
851                                                TemplateTypeParmTypeLoc TL) {
852  TemplateTypeParmType *T = TL.getTypePtr();
853  if (T->getDepth() < TemplateArgs.getNumLevels()) {
854    // Replace the template type parameter with its corresponding
855    // template argument.
856
857    // If the corresponding template argument is NULL or doesn't exist, it's
858    // because we are performing instantiation from explicitly-specified
859    // template arguments in a function template class, but there were some
860    // arguments left unspecified.
861    if (!TemplateArgs.hasTemplateArgument(T->getDepth(), T->getIndex())) {
862      TemplateTypeParmTypeLoc NewTL
863        = TLB.push<TemplateTypeParmTypeLoc>(TL.getType());
864      NewTL.setNameLoc(TL.getNameLoc());
865      return TL.getType();
866    }
867
868    assert(TemplateArgs(T->getDepth(), T->getIndex()).getKind()
869             == TemplateArgument::Type &&
870           "Template argument kind mismatch");
871
872    QualType Replacement
873      = TemplateArgs(T->getDepth(), T->getIndex()).getAsType();
874
875    // TODO: only do this uniquing once, at the start of instantiation.
876    QualType Result
877      = getSema().Context.getSubstTemplateTypeParmType(T, Replacement);
878    SubstTemplateTypeParmTypeLoc NewTL
879      = TLB.push<SubstTemplateTypeParmTypeLoc>(Result);
880    NewTL.setNameLoc(TL.getNameLoc());
881    return Result;
882  }
883
884  // The template type parameter comes from an inner template (e.g.,
885  // the template parameter list of a member template inside the
886  // template we are instantiating). Create a new template type
887  // parameter with the template "level" reduced by one.
888  QualType Result
889    = getSema().Context.getTemplateTypeParmType(T->getDepth()
890                                                 - TemplateArgs.getNumLevels(),
891                                                T->getIndex(),
892                                                T->isParameterPack(),
893                                                T->getName());
894  TemplateTypeParmTypeLoc NewTL = TLB.push<TemplateTypeParmTypeLoc>(Result);
895  NewTL.setNameLoc(TL.getNameLoc());
896  return Result;
897}
898
899/// \brief Perform substitution on the type T with a given set of template
900/// arguments.
901///
902/// This routine substitutes the given template arguments into the
903/// type T and produces the instantiated type.
904///
905/// \param T the type into which the template arguments will be
906/// substituted. If this type is not dependent, it will be returned
907/// immediately.
908///
909/// \param TemplateArgs the template arguments that will be
910/// substituted for the top-level template parameters within T.
911///
912/// \param Loc the location in the source code where this substitution
913/// is being performed. It will typically be the location of the
914/// declarator (if we're instantiating the type of some declaration)
915/// or the location of the type in the source code (if, e.g., we're
916/// instantiating the type of a cast expression).
917///
918/// \param Entity the name of the entity associated with a declaration
919/// being instantiated (if any). May be empty to indicate that there
920/// is no such entity (if, e.g., this is a type that occurs as part of
921/// a cast expression) or that the entity has no name (e.g., an
922/// unnamed function parameter).
923///
924/// \returns If the instantiation succeeds, the instantiated
925/// type. Otherwise, produces diagnostics and returns a NULL type.
926TypeSourceInfo *Sema::SubstType(TypeSourceInfo *T,
927                                const MultiLevelTemplateArgumentList &Args,
928                                SourceLocation Loc,
929                                DeclarationName Entity) {
930  assert(!ActiveTemplateInstantiations.empty() &&
931         "Cannot perform an instantiation without some context on the "
932         "instantiation stack");
933
934  if (!T->getType()->isDependentType())
935    return T;
936
937  TemplateInstantiator Instantiator(*this, Args, Loc, Entity);
938  return Instantiator.TransformType(T);
939}
940
941/// Deprecated form of the above.
942QualType Sema::SubstType(QualType T,
943                         const MultiLevelTemplateArgumentList &TemplateArgs,
944                         SourceLocation Loc, DeclarationName Entity) {
945  assert(!ActiveTemplateInstantiations.empty() &&
946         "Cannot perform an instantiation without some context on the "
947         "instantiation stack");
948
949  // If T is not a dependent type, there is nothing to do.
950  if (!T->isDependentType())
951    return T;
952
953  TemplateInstantiator Instantiator(*this, TemplateArgs, Loc, Entity);
954  return Instantiator.TransformType(T);
955}
956
957/// \brief Perform substitution on the base class specifiers of the
958/// given class template specialization.
959///
960/// Produces a diagnostic and returns true on error, returns false and
961/// attaches the instantiated base classes to the class template
962/// specialization if successful.
963bool
964Sema::SubstBaseSpecifiers(CXXRecordDecl *Instantiation,
965                          CXXRecordDecl *Pattern,
966                          const MultiLevelTemplateArgumentList &TemplateArgs) {
967  bool Invalid = false;
968  llvm::SmallVector<CXXBaseSpecifier*, 4> InstantiatedBases;
969  for (ClassTemplateSpecializationDecl::base_class_iterator
970         Base = Pattern->bases_begin(), BaseEnd = Pattern->bases_end();
971       Base != BaseEnd; ++Base) {
972    if (!Base->getType()->isDependentType()) {
973      const CXXRecordDecl *BaseDecl =
974        cast<CXXRecordDecl>(Base->getType()->getAs<RecordType>()->getDecl());
975
976      // Make sure to set the attributes from the base.
977      SetClassDeclAttributesFromBase(Instantiation, BaseDecl,
978                                     Base->isVirtual());
979
980      InstantiatedBases.push_back(new (Context) CXXBaseSpecifier(*Base));
981      continue;
982    }
983
984    QualType BaseType = SubstType(Base->getType(),
985                                  TemplateArgs,
986                                  Base->getSourceRange().getBegin(),
987                                  DeclarationName());
988    if (BaseType.isNull()) {
989      Invalid = true;
990      continue;
991    }
992
993    if (CXXBaseSpecifier *InstantiatedBase
994          = CheckBaseSpecifier(Instantiation,
995                               Base->getSourceRange(),
996                               Base->isVirtual(),
997                               Base->getAccessSpecifierAsWritten(),
998                               BaseType,
999                               /*FIXME: Not totally accurate */
1000                               Base->getSourceRange().getBegin()))
1001      InstantiatedBases.push_back(InstantiatedBase);
1002    else
1003      Invalid = true;
1004  }
1005
1006  if (!Invalid &&
1007      AttachBaseSpecifiers(Instantiation, InstantiatedBases.data(),
1008                           InstantiatedBases.size()))
1009    Invalid = true;
1010
1011  return Invalid;
1012}
1013
1014/// \brief Instantiate the definition of a class from a given pattern.
1015///
1016/// \param PointOfInstantiation The point of instantiation within the
1017/// source code.
1018///
1019/// \param Instantiation is the declaration whose definition is being
1020/// instantiated. This will be either a class template specialization
1021/// or a member class of a class template specialization.
1022///
1023/// \param Pattern is the pattern from which the instantiation
1024/// occurs. This will be either the declaration of a class template or
1025/// the declaration of a member class of a class template.
1026///
1027/// \param TemplateArgs The template arguments to be substituted into
1028/// the pattern.
1029///
1030/// \param TSK the kind of implicit or explicit instantiation to perform.
1031///
1032/// \param Complain whether to complain if the class cannot be instantiated due
1033/// to the lack of a definition.
1034///
1035/// \returns true if an error occurred, false otherwise.
1036bool
1037Sema::InstantiateClass(SourceLocation PointOfInstantiation,
1038                       CXXRecordDecl *Instantiation, CXXRecordDecl *Pattern,
1039                       const MultiLevelTemplateArgumentList &TemplateArgs,
1040                       TemplateSpecializationKind TSK,
1041                       bool Complain) {
1042  bool Invalid = false;
1043
1044  CXXRecordDecl *PatternDef
1045    = cast_or_null<CXXRecordDecl>(Pattern->getDefinition(Context));
1046  if (!PatternDef) {
1047    if (!Complain) {
1048      // Say nothing
1049    } else if (Pattern == Instantiation->getInstantiatedFromMemberClass()) {
1050      Diag(PointOfInstantiation,
1051           diag::err_implicit_instantiate_member_undefined)
1052        << Context.getTypeDeclType(Instantiation);
1053      Diag(Pattern->getLocation(), diag::note_member_of_template_here);
1054    } else {
1055      Diag(PointOfInstantiation, diag::err_template_instantiate_undefined)
1056        << (TSK != TSK_ImplicitInstantiation)
1057        << Context.getTypeDeclType(Instantiation);
1058      Diag(Pattern->getLocation(), diag::note_template_decl_here);
1059    }
1060    return true;
1061  }
1062  Pattern = PatternDef;
1063
1064  // \brief Record the point of instantiation.
1065  if (MemberSpecializationInfo *MSInfo
1066        = Instantiation->getMemberSpecializationInfo()) {
1067    MSInfo->setTemplateSpecializationKind(TSK);
1068    MSInfo->setPointOfInstantiation(PointOfInstantiation);
1069  } else if (ClassTemplateSpecializationDecl *Spec
1070               = dyn_cast<ClassTemplateSpecializationDecl>(Instantiation)) {
1071    Spec->setTemplateSpecializationKind(TSK);
1072    Spec->setPointOfInstantiation(PointOfInstantiation);
1073  }
1074
1075  InstantiatingTemplate Inst(*this, PointOfInstantiation, Instantiation);
1076  if (Inst)
1077    return true;
1078
1079  // Enter the scope of this instantiation. We don't use
1080  // PushDeclContext because we don't have a scope.
1081  DeclContext *PreviousContext = CurContext;
1082  CurContext = Instantiation;
1083
1084  // Start the definition of this instantiation.
1085  Instantiation->startDefinition();
1086
1087  // Do substitution on the base class specifiers.
1088  if (SubstBaseSpecifiers(Instantiation, Pattern, TemplateArgs))
1089    Invalid = true;
1090
1091  llvm::SmallVector<DeclPtrTy, 4> Fields;
1092  for (RecordDecl::decl_iterator Member = Pattern->decls_begin(),
1093         MemberEnd = Pattern->decls_end();
1094       Member != MemberEnd; ++Member) {
1095    Decl *NewMember = SubstDecl(*Member, Instantiation, TemplateArgs);
1096    if (NewMember) {
1097      if (FieldDecl *Field = dyn_cast<FieldDecl>(NewMember))
1098        Fields.push_back(DeclPtrTy::make(Field));
1099      else if (NewMember->isInvalidDecl())
1100        Invalid = true;
1101    } else {
1102      // FIXME: Eventually, a NULL return will mean that one of the
1103      // instantiations was a semantic disaster, and we'll want to set Invalid =
1104      // true. For now, we expect to skip some members that we can't yet handle.
1105    }
1106  }
1107
1108  // Finish checking fields.
1109  ActOnFields(0, Instantiation->getLocation(), DeclPtrTy::make(Instantiation),
1110              Fields.data(), Fields.size(), SourceLocation(), SourceLocation(),
1111              0);
1112  CheckCompletedCXXClass(Instantiation);
1113  if (Instantiation->isInvalidDecl())
1114    Invalid = true;
1115
1116  // Exit the scope of this instantiation.
1117  CurContext = PreviousContext;
1118
1119  // If this is a polymorphic C++ class without a key function, we'll
1120  // have to mark all of the virtual members to allow emission of a vtable
1121  // in this translation unit.
1122  if (Instantiation->isDynamicClass() && !Context.getKeyFunction(Instantiation))
1123      ClassesWithUnmarkedVirtualMembers.push_back(std::make_pair(Instantiation,
1124                                                       PointOfInstantiation));
1125
1126  if (!Invalid)
1127    Consumer.HandleTagDeclDefinition(Instantiation);
1128
1129  return Invalid;
1130}
1131
1132bool
1133Sema::InstantiateClassTemplateSpecialization(
1134                           SourceLocation PointOfInstantiation,
1135                           ClassTemplateSpecializationDecl *ClassTemplateSpec,
1136                           TemplateSpecializationKind TSK,
1137                           bool Complain) {
1138  // Perform the actual instantiation on the canonical declaration.
1139  ClassTemplateSpec = cast<ClassTemplateSpecializationDecl>(
1140                                         ClassTemplateSpec->getCanonicalDecl());
1141
1142  // Check whether we have already instantiated or specialized this class
1143  // template specialization.
1144  if (ClassTemplateSpec->getSpecializationKind() != TSK_Undeclared) {
1145    if (ClassTemplateSpec->getSpecializationKind() ==
1146          TSK_ExplicitInstantiationDeclaration &&
1147        TSK == TSK_ExplicitInstantiationDefinition) {
1148      // An explicit instantiation definition follows an explicit instantiation
1149      // declaration (C++0x [temp.explicit]p10); go ahead and perform the
1150      // explicit instantiation.
1151      ClassTemplateSpec->setSpecializationKind(TSK);
1152      return false;
1153    }
1154
1155    // We can only instantiate something that hasn't already been
1156    // instantiated or specialized. Fail without any diagnostics: our
1157    // caller will provide an error message.
1158    return true;
1159  }
1160
1161  if (ClassTemplateSpec->isInvalidDecl())
1162    return true;
1163
1164  ClassTemplateDecl *Template = ClassTemplateSpec->getSpecializedTemplate();
1165  CXXRecordDecl *Pattern = 0;
1166
1167  // C++ [temp.class.spec.match]p1:
1168  //   When a class template is used in a context that requires an
1169  //   instantiation of the class, it is necessary to determine
1170  //   whether the instantiation is to be generated using the primary
1171  //   template or one of the partial specializations. This is done by
1172  //   matching the template arguments of the class template
1173  //   specialization with the template argument lists of the partial
1174  //   specializations.
1175  typedef std::pair<ClassTemplatePartialSpecializationDecl *,
1176                    TemplateArgumentList *> MatchResult;
1177  llvm::SmallVector<MatchResult, 4> Matched;
1178  for (llvm::FoldingSet<ClassTemplatePartialSpecializationDecl>::iterator
1179         Partial = Template->getPartialSpecializations().begin(),
1180         PartialEnd = Template->getPartialSpecializations().end();
1181       Partial != PartialEnd;
1182       ++Partial) {
1183    TemplateDeductionInfo Info(Context);
1184    if (TemplateDeductionResult Result
1185          = DeduceTemplateArguments(&*Partial,
1186                                    ClassTemplateSpec->getTemplateArgs(),
1187                                    Info)) {
1188      // FIXME: Store the failed-deduction information for use in
1189      // diagnostics, later.
1190      (void)Result;
1191    } else {
1192      Matched.push_back(std::make_pair(&*Partial, Info.take()));
1193    }
1194  }
1195
1196  if (Matched.size() >= 1) {
1197    llvm::SmallVector<MatchResult, 4>::iterator Best = Matched.begin();
1198    if (Matched.size() == 1) {
1199      //   -- If exactly one matching specialization is found, the
1200      //      instantiation is generated from that specialization.
1201      // We don't need to do anything for this.
1202    } else {
1203      //   -- If more than one matching specialization is found, the
1204      //      partial order rules (14.5.4.2) are used to determine
1205      //      whether one of the specializations is more specialized
1206      //      than the others. If none of the specializations is more
1207      //      specialized than all of the other matching
1208      //      specializations, then the use of the class template is
1209      //      ambiguous and the program is ill-formed.
1210      for (llvm::SmallVector<MatchResult, 4>::iterator P = Best + 1,
1211                                                    PEnd = Matched.end();
1212           P != PEnd; ++P) {
1213        if (getMoreSpecializedPartialSpecialization(P->first, Best->first)
1214              == P->first)
1215          Best = P;
1216      }
1217
1218      // Determine if the best partial specialization is more specialized than
1219      // the others.
1220      bool Ambiguous = false;
1221      for (llvm::SmallVector<MatchResult, 4>::iterator P = Matched.begin(),
1222                                                    PEnd = Matched.end();
1223           P != PEnd; ++P) {
1224        if (P != Best &&
1225            getMoreSpecializedPartialSpecialization(P->first, Best->first)
1226              != Best->first) {
1227          Ambiguous = true;
1228          break;
1229        }
1230      }
1231
1232      if (Ambiguous) {
1233        // Partial ordering did not produce a clear winner. Complain.
1234        ClassTemplateSpec->setInvalidDecl();
1235        Diag(PointOfInstantiation, diag::err_partial_spec_ordering_ambiguous)
1236          << ClassTemplateSpec;
1237
1238        // Print the matching partial specializations.
1239        for (llvm::SmallVector<MatchResult, 4>::iterator P = Matched.begin(),
1240                                                      PEnd = Matched.end();
1241             P != PEnd; ++P)
1242          Diag(P->first->getLocation(), diag::note_partial_spec_match)
1243            << getTemplateArgumentBindingsText(P->first->getTemplateParameters(),
1244                                               *P->second);
1245
1246        return true;
1247      }
1248    }
1249
1250    // Instantiate using the best class template partial specialization.
1251    ClassTemplatePartialSpecializationDecl *OrigPartialSpec = Best->first;
1252    while (OrigPartialSpec->getInstantiatedFromMember()) {
1253      // If we've found an explicit specialization of this class template,
1254      // stop here and use that as the pattern.
1255      if (OrigPartialSpec->isMemberSpecialization())
1256        break;
1257
1258      OrigPartialSpec = OrigPartialSpec->getInstantiatedFromMember();
1259    }
1260
1261    Pattern = OrigPartialSpec;
1262    ClassTemplateSpec->setInstantiationOf(Best->first, Best->second);
1263  } else {
1264    //   -- If no matches are found, the instantiation is generated
1265    //      from the primary template.
1266    ClassTemplateDecl *OrigTemplate = Template;
1267    while (OrigTemplate->getInstantiatedFromMemberTemplate()) {
1268      // If we've found an explicit specialization of this class template,
1269      // stop here and use that as the pattern.
1270      if (OrigTemplate->isMemberSpecialization())
1271        break;
1272
1273      OrigTemplate = OrigTemplate->getInstantiatedFromMemberTemplate();
1274    }
1275
1276    Pattern = OrigTemplate->getTemplatedDecl();
1277  }
1278
1279  bool Result = InstantiateClass(PointOfInstantiation, ClassTemplateSpec,
1280                                 Pattern,
1281                                getTemplateInstantiationArgs(ClassTemplateSpec),
1282                                 TSK,
1283                                 Complain);
1284
1285  for (unsigned I = 0, N = Matched.size(); I != N; ++I) {
1286    // FIXME: Implement TemplateArgumentList::Destroy!
1287    //    if (Matched[I].first != Pattern)
1288    //      Matched[I].second->Destroy(Context);
1289  }
1290
1291  return Result;
1292}
1293
1294/// \brief Instantiates the definitions of all of the member
1295/// of the given class, which is an instantiation of a class template
1296/// or a member class of a template.
1297void
1298Sema::InstantiateClassMembers(SourceLocation PointOfInstantiation,
1299                              CXXRecordDecl *Instantiation,
1300                        const MultiLevelTemplateArgumentList &TemplateArgs,
1301                              TemplateSpecializationKind TSK) {
1302  for (DeclContext::decl_iterator D = Instantiation->decls_begin(),
1303                               DEnd = Instantiation->decls_end();
1304       D != DEnd; ++D) {
1305    bool SuppressNew = false;
1306    if (FunctionDecl *Function = dyn_cast<FunctionDecl>(*D)) {
1307      if (FunctionDecl *Pattern
1308            = Function->getInstantiatedFromMemberFunction()) {
1309        MemberSpecializationInfo *MSInfo
1310          = Function->getMemberSpecializationInfo();
1311        assert(MSInfo && "No member specialization information?");
1312        if (CheckSpecializationInstantiationRedecl(PointOfInstantiation, TSK,
1313                                                   Function,
1314                                        MSInfo->getTemplateSpecializationKind(),
1315                                              MSInfo->getPointOfInstantiation(),
1316                                                   SuppressNew) ||
1317            SuppressNew)
1318          continue;
1319
1320        if (Function->getBody())
1321          continue;
1322
1323        if (TSK == TSK_ExplicitInstantiationDefinition) {
1324          // C++0x [temp.explicit]p8:
1325          //   An explicit instantiation definition that names a class template
1326          //   specialization explicitly instantiates the class template
1327          //   specialization and is only an explicit instantiation definition
1328          //   of members whose definition is visible at the point of
1329          //   instantiation.
1330          if (!Pattern->getBody())
1331            continue;
1332
1333          Function->setTemplateSpecializationKind(TSK, PointOfInstantiation);
1334
1335          InstantiateFunctionDefinition(PointOfInstantiation, Function);
1336        } else {
1337          Function->setTemplateSpecializationKind(TSK, PointOfInstantiation);
1338        }
1339      }
1340    } else if (VarDecl *Var = dyn_cast<VarDecl>(*D)) {
1341      if (Var->isStaticDataMember()) {
1342        MemberSpecializationInfo *MSInfo = Var->getMemberSpecializationInfo();
1343        assert(MSInfo && "No member specialization information?");
1344        if (CheckSpecializationInstantiationRedecl(PointOfInstantiation, TSK,
1345                                                   Var,
1346                                        MSInfo->getTemplateSpecializationKind(),
1347                                              MSInfo->getPointOfInstantiation(),
1348                                                   SuppressNew) ||
1349            SuppressNew)
1350          continue;
1351
1352        if (TSK == TSK_ExplicitInstantiationDefinition) {
1353          // C++0x [temp.explicit]p8:
1354          //   An explicit instantiation definition that names a class template
1355          //   specialization explicitly instantiates the class template
1356          //   specialization and is only an explicit instantiation definition
1357          //   of members whose definition is visible at the point of
1358          //   instantiation.
1359          if (!Var->getInstantiatedFromStaticDataMember()
1360                                                     ->getOutOfLineDefinition())
1361            continue;
1362
1363          Var->setTemplateSpecializationKind(TSK, PointOfInstantiation);
1364          InstantiateStaticDataMemberDefinition(PointOfInstantiation, Var);
1365        } else {
1366          Var->setTemplateSpecializationKind(TSK, PointOfInstantiation);
1367        }
1368      }
1369    } else if (CXXRecordDecl *Record = dyn_cast<CXXRecordDecl>(*D)) {
1370      if (Record->isInjectedClassName())
1371        continue;
1372
1373      MemberSpecializationInfo *MSInfo = Record->getMemberSpecializationInfo();
1374      assert(MSInfo && "No member specialization information?");
1375      if (CheckSpecializationInstantiationRedecl(PointOfInstantiation, TSK,
1376                                                 Record,
1377                                        MSInfo->getTemplateSpecializationKind(),
1378                                              MSInfo->getPointOfInstantiation(),
1379                                                 SuppressNew) ||
1380          SuppressNew)
1381        continue;
1382
1383      CXXRecordDecl *Pattern = Record->getInstantiatedFromMemberClass();
1384      assert(Pattern && "Missing instantiated-from-template information");
1385
1386      if (!Record->getDefinition(Context)) {
1387        if (!Pattern->getDefinition(Context)) {
1388          // C++0x [temp.explicit]p8:
1389          //   An explicit instantiation definition that names a class template
1390          //   specialization explicitly instantiates the class template
1391          //   specialization and is only an explicit instantiation definition
1392          //   of members whose definition is visible at the point of
1393          //   instantiation.
1394          if (TSK == TSK_ExplicitInstantiationDeclaration) {
1395            MSInfo->setTemplateSpecializationKind(TSK);
1396            MSInfo->setPointOfInstantiation(PointOfInstantiation);
1397          }
1398
1399          continue;
1400        }
1401
1402        InstantiateClass(PointOfInstantiation, Record, Pattern,
1403                         TemplateArgs,
1404                         TSK);
1405      }
1406
1407      Pattern = cast_or_null<CXXRecordDecl>(Record->getDefinition(Context));
1408      if (Pattern)
1409        InstantiateClassMembers(PointOfInstantiation, Pattern, TemplateArgs,
1410                                TSK);
1411    }
1412  }
1413}
1414
1415/// \brief Instantiate the definitions of all of the members of the
1416/// given class template specialization, which was named as part of an
1417/// explicit instantiation.
1418void
1419Sema::InstantiateClassTemplateSpecializationMembers(
1420                                           SourceLocation PointOfInstantiation,
1421                            ClassTemplateSpecializationDecl *ClassTemplateSpec,
1422                                               TemplateSpecializationKind TSK) {
1423  // C++0x [temp.explicit]p7:
1424  //   An explicit instantiation that names a class template
1425  //   specialization is an explicit instantion of the same kind
1426  //   (declaration or definition) of each of its members (not
1427  //   including members inherited from base classes) that has not
1428  //   been previously explicitly specialized in the translation unit
1429  //   containing the explicit instantiation, except as described
1430  //   below.
1431  InstantiateClassMembers(PointOfInstantiation, ClassTemplateSpec,
1432                          getTemplateInstantiationArgs(ClassTemplateSpec),
1433                          TSK);
1434}
1435
1436Sema::OwningStmtResult
1437Sema::SubstStmt(Stmt *S, const MultiLevelTemplateArgumentList &TemplateArgs) {
1438  if (!S)
1439    return Owned(S);
1440
1441  TemplateInstantiator Instantiator(*this, TemplateArgs,
1442                                    SourceLocation(),
1443                                    DeclarationName());
1444  return Instantiator.TransformStmt(S);
1445}
1446
1447Sema::OwningExprResult
1448Sema::SubstExpr(Expr *E, const MultiLevelTemplateArgumentList &TemplateArgs) {
1449  if (!E)
1450    return Owned(E);
1451
1452  TemplateInstantiator Instantiator(*this, TemplateArgs,
1453                                    SourceLocation(),
1454                                    DeclarationName());
1455  return Instantiator.TransformExpr(E);
1456}
1457
1458/// \brief Do template substitution on a nested-name-specifier.
1459NestedNameSpecifier *
1460Sema::SubstNestedNameSpecifier(NestedNameSpecifier *NNS,
1461                               SourceRange Range,
1462                         const MultiLevelTemplateArgumentList &TemplateArgs) {
1463  TemplateInstantiator Instantiator(*this, TemplateArgs, Range.getBegin(),
1464                                    DeclarationName());
1465  return Instantiator.TransformNestedNameSpecifier(NNS, Range);
1466}
1467
1468TemplateName
1469Sema::SubstTemplateName(TemplateName Name, SourceLocation Loc,
1470                        const MultiLevelTemplateArgumentList &TemplateArgs) {
1471  TemplateInstantiator Instantiator(*this, TemplateArgs, Loc,
1472                                    DeclarationName());
1473  return Instantiator.TransformTemplateName(Name);
1474}
1475
1476bool Sema::Subst(const TemplateArgumentLoc &Input, TemplateArgumentLoc &Output,
1477                 const MultiLevelTemplateArgumentList &TemplateArgs) {
1478  TemplateInstantiator Instantiator(*this, TemplateArgs, SourceLocation(),
1479                                    DeclarationName());
1480
1481  return Instantiator.TransformTemplateArgument(Input, Output);
1482}
1483