SemaTemplateInstantiate.cpp revision e688ddf351d5d77d18cd01727e672e4b69706b23 
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 "clang/Sema/SemaInternal.h"
14#include "TreeTransform.h"
15#include "clang/AST/ASTConsumer.h"
16#include "clang/AST/ASTContext.h"
17#include "clang/AST/DeclTemplate.h"
18#include "clang/AST/Expr.h"
19#include "clang/Basic/LangOptions.h"
20#include "clang/Sema/DeclSpec.h"
21#include "clang/Sema/Initialization.h"
22#include "clang/Sema/Lookup.h"
23#include "clang/Sema/Template.h"
24#include "clang/Sema/TemplateDeduction.h"
25
26using namespace clang;
27using namespace sema;
28
29//===----------------------------------------------------------------------===/
30// Template Instantiation Support
31//===----------------------------------------------------------------------===/
32
33/// \brief Retrieve the template argument list(s) that should be used to
34/// instantiate the definition of the given declaration.
35///
36/// \param D the declaration for which we are computing template instantiation
37/// arguments.
38///
39/// \param Innermost if non-NULL, the innermost template argument list.
40///
41/// \param RelativeToPrimary true if we should get the template
42/// arguments relative to the primary template, even when we're
43/// dealing with a specialization. This is only relevant for function
44/// template specializations.
45///
46/// \param Pattern If non-NULL, indicates the pattern from which we will be
47/// instantiating the definition of the given declaration, \p D. This is
48/// used to determine the proper set of template instantiation arguments for
49/// friend function template specializations.
50MultiLevelTemplateArgumentList
51Sema::getTemplateInstantiationArgs(NamedDecl *D,
52                                   const TemplateArgumentList *Innermost,
53                                   bool RelativeToPrimary,
54                                   const FunctionDecl *Pattern) {
55  // Accumulate the set of template argument lists in this structure.
56  MultiLevelTemplateArgumentList Result;
57
58  if (Innermost)
59    Result.addOuterTemplateArguments(Innermost);
60
61  DeclContext *Ctx = dyn_cast<DeclContext>(D);
62  if (!Ctx) {
63    Ctx = D->getDeclContext();
64
65    // Add template arguments from a variable template instantiation.
66    if (VarTemplateSpecializationDecl *Spec =
67            dyn_cast<VarTemplateSpecializationDecl>(D)) {
68      // We're done when we hit an explicit specialization.
69      if (Spec->getSpecializationKind() == TSK_ExplicitSpecialization &&
70          !isa<VarTemplatePartialSpecializationDecl>(Spec))
71        return Result;
72
73      Result.addOuterTemplateArguments(&Spec->getTemplateInstantiationArgs());
74
75      // If this variable template specialization was instantiated from a
76      // specialized member that is a variable template, we're done.
77      assert(Spec->getSpecializedTemplate() && "No variable template?");
78      if (Spec->getSpecializedTemplate()->isMemberSpecialization())
79        return Result;
80    }
81
82    // If we have a template template parameter with translation unit context,
83    // then we're performing substitution into a default template argument of
84    // this template template parameter before we've constructed the template
85    // that will own this template template parameter. In this case, we
86    // use empty template parameter lists for all of the outer templates
87    // to avoid performing any substitutions.
88    if (Ctx->isTranslationUnit()) {
89      if (TemplateTemplateParmDecl *TTP
90                                      = dyn_cast<TemplateTemplateParmDecl>(D)) {
91        for (unsigned I = 0, N = TTP->getDepth() + 1; I != N; ++I)
92          Result.addOuterTemplateArguments(None);
93        return Result;
94      }
95    }
96  }
97
98  while (!Ctx->isFileContext()) {
99    // Add template arguments from a class template instantiation.
100    if (ClassTemplateSpecializationDecl *Spec
101          = dyn_cast<ClassTemplateSpecializationDecl>(Ctx)) {
102      // We're done when we hit an explicit specialization.
103      if (Spec->getSpecializationKind() == TSK_ExplicitSpecialization &&
104          !isa<ClassTemplatePartialSpecializationDecl>(Spec))
105        break;
106
107      Result.addOuterTemplateArguments(&Spec->getTemplateInstantiationArgs());
108
109      // If this class template specialization was instantiated from a
110      // specialized member that is a class template, we're done.
111      assert(Spec->getSpecializedTemplate() && "No class template?");
112      if (Spec->getSpecializedTemplate()->isMemberSpecialization())
113        break;
114    }
115    // Add template arguments from a function template specialization.
116    else if (FunctionDecl *Function = dyn_cast<FunctionDecl>(Ctx)) {
117      if (!RelativeToPrimary &&
118          (Function->getTemplateSpecializationKind() ==
119                                                  TSK_ExplicitSpecialization &&
120           !Function->getClassScopeSpecializationPattern()))
121        break;
122
123      if (const TemplateArgumentList *TemplateArgs
124            = Function->getTemplateSpecializationArgs()) {
125        // Add the template arguments for this specialization.
126        Result.addOuterTemplateArguments(TemplateArgs);
127
128        // If this function was instantiated from a specialized member that is
129        // a function template, we're done.
130        assert(Function->getPrimaryTemplate() && "No function template?");
131        if (Function->getPrimaryTemplate()->isMemberSpecialization())
132          break;
133      } else if (FunctionTemplateDecl *FunTmpl
134                                   = Function->getDescribedFunctionTemplate()) {
135        // Add the "injected" template arguments.
136        Result.addOuterTemplateArguments(FunTmpl->getInjectedTemplateArgs());
137      }
138
139      // If this is a friend declaration and it declares an entity at
140      // namespace scope, take arguments from its lexical parent
141      // instead of its semantic parent, unless of course the pattern we're
142      // instantiating actually comes from the file's context!
143      if (Function->getFriendObjectKind() &&
144          Function->getDeclContext()->isFileContext() &&
145          (!Pattern || !Pattern->getLexicalDeclContext()->isFileContext())) {
146        Ctx = Function->getLexicalDeclContext();
147        RelativeToPrimary = false;
148        continue;
149      }
150    } else if (CXXRecordDecl *Rec = dyn_cast<CXXRecordDecl>(Ctx)) {
151      if (ClassTemplateDecl *ClassTemplate = Rec->getDescribedClassTemplate()) {
152        QualType T = ClassTemplate->getInjectedClassNameSpecialization();
153        const TemplateSpecializationType *TST =
154            cast<TemplateSpecializationType>(Context.getCanonicalType(T));
155        Result.addOuterTemplateArguments(
156            llvm::makeArrayRef(TST->getArgs(), TST->getNumArgs()));
157        if (ClassTemplate->isMemberSpecialization())
158          break;
159      }
160    }
161
162    Ctx = Ctx->getParent();
163    RelativeToPrimary = false;
164  }
165
166  return Result;
167}
168
169bool Sema::ActiveTemplateInstantiation::isInstantiationRecord() const {
170  switch (Kind) {
171  case TemplateInstantiation:
172  case ExceptionSpecInstantiation:
173  case DefaultTemplateArgumentInstantiation:
174  case DefaultFunctionArgumentInstantiation:
175  case ExplicitTemplateArgumentSubstitution:
176  case DeducedTemplateArgumentSubstitution:
177  case PriorTemplateArgumentSubstitution:
178    return true;
179
180  case DefaultTemplateArgumentChecking:
181    return false;
182  }
183
184  llvm_unreachable("Invalid InstantiationKind!");
185}
186
187Sema::InstantiatingTemplate::
188InstantiatingTemplate(Sema &SemaRef, SourceLocation PointOfInstantiation,
189                      Decl *Entity,
190                      SourceRange InstantiationRange)
191  : SemaRef(SemaRef),
192    SavedInNonInstantiationSFINAEContext(
193                                        SemaRef.InNonInstantiationSFINAEContext)
194{
195  Invalid = CheckInstantiationDepth(PointOfInstantiation,
196                                    InstantiationRange);
197  if (!Invalid) {
198    ActiveTemplateInstantiation Inst;
199    Inst.Kind = ActiveTemplateInstantiation::TemplateInstantiation;
200    Inst.PointOfInstantiation = PointOfInstantiation;
201    Inst.Entity = Entity;
202    Inst.TemplateArgs = 0;
203    Inst.NumTemplateArgs = 0;
204    Inst.InstantiationRange = InstantiationRange;
205    SemaRef.InNonInstantiationSFINAEContext = false;
206    SemaRef.ActiveTemplateInstantiations.push_back(Inst);
207  }
208}
209
210Sema::InstantiatingTemplate::
211InstantiatingTemplate(Sema &SemaRef, SourceLocation PointOfInstantiation,
212                      FunctionDecl *Entity, ExceptionSpecification,
213                      SourceRange InstantiationRange)
214  : SemaRef(SemaRef),
215    SavedInNonInstantiationSFINAEContext(
216                                        SemaRef.InNonInstantiationSFINAEContext)
217{
218  Invalid = CheckInstantiationDepth(PointOfInstantiation,
219                                    InstantiationRange);
220  if (!Invalid) {
221    ActiveTemplateInstantiation Inst;
222    Inst.Kind = ActiveTemplateInstantiation::ExceptionSpecInstantiation;
223    Inst.PointOfInstantiation = PointOfInstantiation;
224    Inst.Entity = Entity;
225    Inst.TemplateArgs = 0;
226    Inst.NumTemplateArgs = 0;
227    Inst.InstantiationRange = InstantiationRange;
228    SemaRef.InNonInstantiationSFINAEContext = false;
229    SemaRef.ActiveTemplateInstantiations.push_back(Inst);
230  }
231}
232
233Sema::InstantiatingTemplate::
234InstantiatingTemplate(Sema &SemaRef, SourceLocation PointOfInstantiation,
235                      TemplateDecl *Template,
236                      ArrayRef<TemplateArgument> TemplateArgs,
237                      SourceRange InstantiationRange)
238  : SemaRef(SemaRef),
239    SavedInNonInstantiationSFINAEContext(
240                                     SemaRef.InNonInstantiationSFINAEContext)
241{
242  Invalid = CheckInstantiationDepth(PointOfInstantiation,
243                                    InstantiationRange);
244  if (!Invalid) {
245    ActiveTemplateInstantiation Inst;
246    Inst.Kind
247      = ActiveTemplateInstantiation::DefaultTemplateArgumentInstantiation;
248    Inst.PointOfInstantiation = PointOfInstantiation;
249    Inst.Entity = Template;
250    Inst.TemplateArgs = TemplateArgs.data();
251    Inst.NumTemplateArgs = TemplateArgs.size();
252    Inst.InstantiationRange = InstantiationRange;
253    SemaRef.InNonInstantiationSFINAEContext = false;
254    SemaRef.ActiveTemplateInstantiations.push_back(Inst);
255  }
256}
257
258Sema::InstantiatingTemplate::
259InstantiatingTemplate(Sema &SemaRef, SourceLocation PointOfInstantiation,
260                      FunctionTemplateDecl *FunctionTemplate,
261                      ArrayRef<TemplateArgument> TemplateArgs,
262                      ActiveTemplateInstantiation::InstantiationKind Kind,
263                      sema::TemplateDeductionInfo &DeductionInfo,
264                      SourceRange InstantiationRange)
265  : SemaRef(SemaRef),
266    SavedInNonInstantiationSFINAEContext(
267                                     SemaRef.InNonInstantiationSFINAEContext)
268{
269  Invalid = CheckInstantiationDepth(PointOfInstantiation, InstantiationRange);
270  if (!Invalid) {
271    ActiveTemplateInstantiation Inst;
272    Inst.Kind = Kind;
273    Inst.PointOfInstantiation = PointOfInstantiation;
274    Inst.Entity = FunctionTemplate;
275    Inst.TemplateArgs = TemplateArgs.data();
276    Inst.NumTemplateArgs = TemplateArgs.size();
277    Inst.DeductionInfo = &DeductionInfo;
278    Inst.InstantiationRange = InstantiationRange;
279    SemaRef.InNonInstantiationSFINAEContext = false;
280    SemaRef.ActiveTemplateInstantiations.push_back(Inst);
281
282    if (!Inst.isInstantiationRecord())
283      ++SemaRef.NonInstantiationEntries;
284  }
285}
286
287Sema::InstantiatingTemplate::
288InstantiatingTemplate(Sema &SemaRef, SourceLocation PointOfInstantiation,
289                      ClassTemplatePartialSpecializationDecl *PartialSpec,
290                      ArrayRef<TemplateArgument> TemplateArgs,
291                      sema::TemplateDeductionInfo &DeductionInfo,
292                      SourceRange InstantiationRange)
293  : SemaRef(SemaRef),
294    SavedInNonInstantiationSFINAEContext(
295                                     SemaRef.InNonInstantiationSFINAEContext)
296{
297  Invalid = CheckInstantiationDepth(PointOfInstantiation, InstantiationRange);
298  if (!Invalid) {
299    ActiveTemplateInstantiation Inst;
300    Inst.Kind = ActiveTemplateInstantiation::DeducedTemplateArgumentSubstitution;
301    Inst.PointOfInstantiation = PointOfInstantiation;
302    Inst.Entity = PartialSpec;
303    Inst.TemplateArgs = TemplateArgs.data();
304    Inst.NumTemplateArgs = TemplateArgs.size();
305    Inst.DeductionInfo = &DeductionInfo;
306    Inst.InstantiationRange = InstantiationRange;
307    SemaRef.InNonInstantiationSFINAEContext = false;
308    SemaRef.ActiveTemplateInstantiations.push_back(Inst);
309  }
310}
311
312Sema::InstantiatingTemplate::InstantiatingTemplate(
313    Sema &SemaRef, SourceLocation PointOfInstantiation,
314    VarTemplatePartialSpecializationDecl *PartialSpec,
315    ArrayRef<TemplateArgument> TemplateArgs,
316    sema::TemplateDeductionInfo &DeductionInfo, SourceRange InstantiationRange)
317    : SemaRef(SemaRef), SavedInNonInstantiationSFINAEContext(
318                            SemaRef.InNonInstantiationSFINAEContext) {
319  Invalid = CheckInstantiationDepth(PointOfInstantiation, InstantiationRange);
320  if (!Invalid) {
321    ActiveTemplateInstantiation Inst;
322    Inst.Kind =
323        ActiveTemplateInstantiation::DeducedTemplateArgumentSubstitution;
324    Inst.PointOfInstantiation = PointOfInstantiation;
325    Inst.Entity = PartialSpec;
326    Inst.TemplateArgs = TemplateArgs.data();
327    Inst.NumTemplateArgs = TemplateArgs.size();
328    Inst.DeductionInfo = &DeductionInfo;
329    Inst.InstantiationRange = InstantiationRange;
330    SemaRef.InNonInstantiationSFINAEContext = false;
331    SemaRef.ActiveTemplateInstantiations.push_back(Inst);
332  }
333}
334
335Sema::InstantiatingTemplate::
336InstantiatingTemplate(Sema &SemaRef, SourceLocation PointOfInstantiation,
337                      ParmVarDecl *Param,
338                      ArrayRef<TemplateArgument> TemplateArgs,
339                      SourceRange InstantiationRange)
340  : SemaRef(SemaRef),
341    SavedInNonInstantiationSFINAEContext(
342                                     SemaRef.InNonInstantiationSFINAEContext)
343{
344  Invalid = CheckInstantiationDepth(PointOfInstantiation, InstantiationRange);
345  if (!Invalid) {
346    ActiveTemplateInstantiation Inst;
347    Inst.Kind
348      = ActiveTemplateInstantiation::DefaultFunctionArgumentInstantiation;
349    Inst.PointOfInstantiation = PointOfInstantiation;
350    Inst.Entity = Param;
351    Inst.TemplateArgs = TemplateArgs.data();
352    Inst.NumTemplateArgs = TemplateArgs.size();
353    Inst.InstantiationRange = InstantiationRange;
354    SemaRef.InNonInstantiationSFINAEContext = false;
355    SemaRef.ActiveTemplateInstantiations.push_back(Inst);
356  }
357}
358
359Sema::InstantiatingTemplate::
360InstantiatingTemplate(Sema &SemaRef, SourceLocation PointOfInstantiation,
361                      NamedDecl *Template, NonTypeTemplateParmDecl *Param,
362                      ArrayRef<TemplateArgument> TemplateArgs,
363                      SourceRange InstantiationRange)
364  : SemaRef(SemaRef),
365    SavedInNonInstantiationSFINAEContext(
366                                     SemaRef.InNonInstantiationSFINAEContext)
367{
368  Invalid = CheckInstantiationDepth(PointOfInstantiation, InstantiationRange);
369  if (!Invalid) {
370    ActiveTemplateInstantiation Inst;
371    Inst.Kind = ActiveTemplateInstantiation::PriorTemplateArgumentSubstitution;
372    Inst.PointOfInstantiation = PointOfInstantiation;
373    Inst.Template = Template;
374    Inst.Entity = Param;
375    Inst.TemplateArgs = TemplateArgs.data();
376    Inst.NumTemplateArgs = TemplateArgs.size();
377    Inst.InstantiationRange = InstantiationRange;
378    SemaRef.InNonInstantiationSFINAEContext = false;
379    SemaRef.ActiveTemplateInstantiations.push_back(Inst);
380  }
381}
382
383Sema::InstantiatingTemplate::
384InstantiatingTemplate(Sema &SemaRef, SourceLocation PointOfInstantiation,
385                      NamedDecl *Template, TemplateTemplateParmDecl *Param,
386                      ArrayRef<TemplateArgument> TemplateArgs,
387                      SourceRange InstantiationRange)
388  : SemaRef(SemaRef),
389    SavedInNonInstantiationSFINAEContext(
390                                     SemaRef.InNonInstantiationSFINAEContext)
391{
392  Invalid = CheckInstantiationDepth(PointOfInstantiation, InstantiationRange);
393  if (!Invalid) {
394    ActiveTemplateInstantiation Inst;
395    Inst.Kind = ActiveTemplateInstantiation::PriorTemplateArgumentSubstitution;
396    Inst.PointOfInstantiation = PointOfInstantiation;
397    Inst.Template = Template;
398    Inst.Entity = Param;
399    Inst.TemplateArgs = TemplateArgs.data();
400    Inst.NumTemplateArgs = TemplateArgs.size();
401    Inst.InstantiationRange = InstantiationRange;
402    SemaRef.InNonInstantiationSFINAEContext = false;
403    SemaRef.ActiveTemplateInstantiations.push_back(Inst);
404  }
405}
406
407Sema::InstantiatingTemplate::
408InstantiatingTemplate(Sema &SemaRef, SourceLocation PointOfInstantiation,
409                      TemplateDecl *Template, NamedDecl *Param,
410                      ArrayRef<TemplateArgument> TemplateArgs,
411                      SourceRange InstantiationRange)
412  : SemaRef(SemaRef),
413    SavedInNonInstantiationSFINAEContext(
414                                     SemaRef.InNonInstantiationSFINAEContext)
415{
416  Invalid = false;
417
418  ActiveTemplateInstantiation Inst;
419  Inst.Kind = ActiveTemplateInstantiation::DefaultTemplateArgumentChecking;
420  Inst.PointOfInstantiation = PointOfInstantiation;
421  Inst.Template = Template;
422  Inst.Entity = Param;
423  Inst.TemplateArgs = TemplateArgs.data();
424  Inst.NumTemplateArgs = TemplateArgs.size();
425  Inst.InstantiationRange = InstantiationRange;
426  SemaRef.InNonInstantiationSFINAEContext = false;
427  SemaRef.ActiveTemplateInstantiations.push_back(Inst);
428
429  assert(!Inst.isInstantiationRecord());
430  ++SemaRef.NonInstantiationEntries;
431}
432
433void Sema::InstantiatingTemplate::Clear() {
434  if (!Invalid) {
435    if (!SemaRef.ActiveTemplateInstantiations.back().isInstantiationRecord()) {
436      assert(SemaRef.NonInstantiationEntries > 0);
437      --SemaRef.NonInstantiationEntries;
438    }
439    SemaRef.InNonInstantiationSFINAEContext
440      = SavedInNonInstantiationSFINAEContext;
441
442    // Name lookup no longer looks in this template's defining module.
443    assert(SemaRef.ActiveTemplateInstantiations.size() >=
444           SemaRef.ActiveTemplateInstantiationLookupModules.size() &&
445           "forgot to remove a lookup module for a template instantiation");
446    if (SemaRef.ActiveTemplateInstantiations.size() ==
447        SemaRef.ActiveTemplateInstantiationLookupModules.size()) {
448      if (Module *M = SemaRef.ActiveTemplateInstantiationLookupModules.back())
449        SemaRef.LookupModulesCache.erase(M);
450      SemaRef.ActiveTemplateInstantiationLookupModules.pop_back();
451    }
452
453    SemaRef.ActiveTemplateInstantiations.pop_back();
454    Invalid = true;
455  }
456}
457
458bool Sema::InstantiatingTemplate::CheckInstantiationDepth(
459                                        SourceLocation PointOfInstantiation,
460                                           SourceRange InstantiationRange) {
461  assert(SemaRef.NonInstantiationEntries <=
462                                   SemaRef.ActiveTemplateInstantiations.size());
463  if ((SemaRef.ActiveTemplateInstantiations.size() -
464          SemaRef.NonInstantiationEntries)
465        <= SemaRef.getLangOpts().InstantiationDepth)
466    return false;
467
468  SemaRef.Diag(PointOfInstantiation,
469               diag::err_template_recursion_depth_exceeded)
470    << SemaRef.getLangOpts().InstantiationDepth
471    << InstantiationRange;
472  SemaRef.Diag(PointOfInstantiation, diag::note_template_recursion_depth)
473    << SemaRef.getLangOpts().InstantiationDepth;
474  return true;
475}
476
477/// \brief Prints the current instantiation stack through a series of
478/// notes.
479void Sema::PrintInstantiationStack() {
480  // Determine which template instantiations to skip, if any.
481  unsigned SkipStart = ActiveTemplateInstantiations.size(), SkipEnd = SkipStart;
482  unsigned Limit = Diags.getTemplateBacktraceLimit();
483  if (Limit && Limit < ActiveTemplateInstantiations.size()) {
484    SkipStart = Limit / 2 + Limit % 2;
485    SkipEnd = ActiveTemplateInstantiations.size() - Limit / 2;
486  }
487
488  // FIXME: In all of these cases, we need to show the template arguments
489  unsigned InstantiationIdx = 0;
490  for (SmallVectorImpl<ActiveTemplateInstantiation>::reverse_iterator
491         Active = ActiveTemplateInstantiations.rbegin(),
492         ActiveEnd = ActiveTemplateInstantiations.rend();
493       Active != ActiveEnd;
494       ++Active, ++InstantiationIdx) {
495    // Skip this instantiation?
496    if (InstantiationIdx >= SkipStart && InstantiationIdx < SkipEnd) {
497      if (InstantiationIdx == SkipStart) {
498        // Note that we're skipping instantiations.
499        Diags.Report(Active->PointOfInstantiation,
500                     diag::note_instantiation_contexts_suppressed)
501          << unsigned(ActiveTemplateInstantiations.size() - Limit);
502      }
503      continue;
504    }
505
506    switch (Active->Kind) {
507    case ActiveTemplateInstantiation::TemplateInstantiation: {
508      Decl *D = Active->Entity;
509      if (CXXRecordDecl *Record = dyn_cast<CXXRecordDecl>(D)) {
510        unsigned DiagID = diag::note_template_member_class_here;
511        if (isa<ClassTemplateSpecializationDecl>(Record))
512          DiagID = diag::note_template_class_instantiation_here;
513        Diags.Report(Active->PointOfInstantiation, DiagID)
514          << Context.getTypeDeclType(Record)
515          << Active->InstantiationRange;
516      } else if (FunctionDecl *Function = dyn_cast<FunctionDecl>(D)) {
517        unsigned DiagID;
518        if (Function->getPrimaryTemplate())
519          DiagID = diag::note_function_template_spec_here;
520        else
521          DiagID = diag::note_template_member_function_here;
522        Diags.Report(Active->PointOfInstantiation, DiagID)
523          << Function
524          << Active->InstantiationRange;
525      } else if (VarDecl *VD = dyn_cast<VarDecl>(D)) {
526        Diags.Report(Active->PointOfInstantiation,
527                     VD->isStaticDataMember()?
528                       diag::note_template_static_data_member_def_here
529                     : diag::note_template_variable_def_here)
530          << VD
531          << Active->InstantiationRange;
532      } else if (EnumDecl *ED = dyn_cast<EnumDecl>(D)) {
533        Diags.Report(Active->PointOfInstantiation,
534                     diag::note_template_enum_def_here)
535          << ED
536          << Active->InstantiationRange;
537      } else {
538        Diags.Report(Active->PointOfInstantiation,
539                     diag::note_template_type_alias_instantiation_here)
540          << cast<TypeAliasTemplateDecl>(D)
541          << Active->InstantiationRange;
542      }
543      break;
544    }
545
546    case ActiveTemplateInstantiation::DefaultTemplateArgumentInstantiation: {
547      TemplateDecl *Template = cast<TemplateDecl>(Active->Entity);
548      SmallVector<char, 128> TemplateArgsStr;
549      llvm::raw_svector_ostream OS(TemplateArgsStr);
550      Template->printName(OS);
551      TemplateSpecializationType::PrintTemplateArgumentList(OS,
552                                                         Active->TemplateArgs,
553                                                      Active->NumTemplateArgs,
554                                                      getPrintingPolicy());
555      Diags.Report(Active->PointOfInstantiation,
556                   diag::note_default_arg_instantiation_here)
557        << OS.str()
558        << Active->InstantiationRange;
559      break;
560    }
561
562    case ActiveTemplateInstantiation::ExplicitTemplateArgumentSubstitution: {
563      FunctionTemplateDecl *FnTmpl = cast<FunctionTemplateDecl>(Active->Entity);
564      Diags.Report(Active->PointOfInstantiation,
565                   diag::note_explicit_template_arg_substitution_here)
566        << FnTmpl
567        << getTemplateArgumentBindingsText(FnTmpl->getTemplateParameters(),
568                                           Active->TemplateArgs,
569                                           Active->NumTemplateArgs)
570        << Active->InstantiationRange;
571      break;
572    }
573
574    case ActiveTemplateInstantiation::DeducedTemplateArgumentSubstitution:
575      if (ClassTemplatePartialSpecializationDecl *PartialSpec =
576            dyn_cast<ClassTemplatePartialSpecializationDecl>(Active->Entity)) {
577        Diags.Report(Active->PointOfInstantiation,
578                     diag::note_partial_spec_deduct_instantiation_here)
579          << Context.getTypeDeclType(PartialSpec)
580          << getTemplateArgumentBindingsText(
581                                         PartialSpec->getTemplateParameters(),
582                                             Active->TemplateArgs,
583                                             Active->NumTemplateArgs)
584          << Active->InstantiationRange;
585      } else {
586        FunctionTemplateDecl *FnTmpl
587          = cast<FunctionTemplateDecl>(Active->Entity);
588        Diags.Report(Active->PointOfInstantiation,
589                     diag::note_function_template_deduction_instantiation_here)
590          << FnTmpl
591          << getTemplateArgumentBindingsText(FnTmpl->getTemplateParameters(),
592                                             Active->TemplateArgs,
593                                             Active->NumTemplateArgs)
594          << Active->InstantiationRange;
595      }
596      break;
597
598    case ActiveTemplateInstantiation::DefaultFunctionArgumentInstantiation: {
599      ParmVarDecl *Param = cast<ParmVarDecl>(Active->Entity);
600      FunctionDecl *FD = cast<FunctionDecl>(Param->getDeclContext());
601
602      SmallVector<char, 128> TemplateArgsStr;
603      llvm::raw_svector_ostream OS(TemplateArgsStr);
604      FD->printName(OS);
605      TemplateSpecializationType::PrintTemplateArgumentList(OS,
606                                                         Active->TemplateArgs,
607                                                      Active->NumTemplateArgs,
608                                                      getPrintingPolicy());
609      Diags.Report(Active->PointOfInstantiation,
610                   diag::note_default_function_arg_instantiation_here)
611        << OS.str()
612        << Active->InstantiationRange;
613      break;
614    }
615
616    case ActiveTemplateInstantiation::PriorTemplateArgumentSubstitution: {
617      NamedDecl *Parm = cast<NamedDecl>(Active->Entity);
618      std::string Name;
619      if (!Parm->getName().empty())
620        Name = std::string(" '") + Parm->getName().str() + "'";
621
622      TemplateParameterList *TemplateParams = 0;
623      if (TemplateDecl *Template = dyn_cast<TemplateDecl>(Active->Template))
624        TemplateParams = Template->getTemplateParameters();
625      else
626        TemplateParams =
627          cast<ClassTemplatePartialSpecializationDecl>(Active->Template)
628                                                      ->getTemplateParameters();
629      Diags.Report(Active->PointOfInstantiation,
630                   diag::note_prior_template_arg_substitution)
631        << isa<TemplateTemplateParmDecl>(Parm)
632        << Name
633        << getTemplateArgumentBindingsText(TemplateParams,
634                                           Active->TemplateArgs,
635                                           Active->NumTemplateArgs)
636        << Active->InstantiationRange;
637      break;
638    }
639
640    case ActiveTemplateInstantiation::DefaultTemplateArgumentChecking: {
641      TemplateParameterList *TemplateParams = 0;
642      if (TemplateDecl *Template = dyn_cast<TemplateDecl>(Active->Template))
643        TemplateParams = Template->getTemplateParameters();
644      else
645        TemplateParams =
646          cast<ClassTemplatePartialSpecializationDecl>(Active->Template)
647                                                      ->getTemplateParameters();
648
649      Diags.Report(Active->PointOfInstantiation,
650                   diag::note_template_default_arg_checking)
651        << getTemplateArgumentBindingsText(TemplateParams,
652                                           Active->TemplateArgs,
653                                           Active->NumTemplateArgs)
654        << Active->InstantiationRange;
655      break;
656    }
657
658    case ActiveTemplateInstantiation::ExceptionSpecInstantiation:
659      Diags.Report(Active->PointOfInstantiation,
660                   diag::note_template_exception_spec_instantiation_here)
661        << cast<FunctionDecl>(Active->Entity)
662        << Active->InstantiationRange;
663      break;
664    }
665  }
666}
667
668Optional<TemplateDeductionInfo *> Sema::isSFINAEContext() const {
669  if (InNonInstantiationSFINAEContext)
670    return Optional<TemplateDeductionInfo *>(0);
671
672  for (SmallVectorImpl<ActiveTemplateInstantiation>::const_reverse_iterator
673         Active = ActiveTemplateInstantiations.rbegin(),
674         ActiveEnd = ActiveTemplateInstantiations.rend();
675       Active != ActiveEnd;
676       ++Active)
677  {
678    switch(Active->Kind) {
679    case ActiveTemplateInstantiation::TemplateInstantiation:
680      // An instantiation of an alias template may or may not be a SFINAE
681      // context, depending on what else is on the stack.
682      if (isa<TypeAliasTemplateDecl>(Active->Entity))
683        break;
684      // Fall through.
685    case ActiveTemplateInstantiation::DefaultFunctionArgumentInstantiation:
686    case ActiveTemplateInstantiation::ExceptionSpecInstantiation:
687      // This is a template instantiation, so there is no SFINAE.
688      return None;
689
690    case ActiveTemplateInstantiation::DefaultTemplateArgumentInstantiation:
691    case ActiveTemplateInstantiation::PriorTemplateArgumentSubstitution:
692    case ActiveTemplateInstantiation::DefaultTemplateArgumentChecking:
693      // A default template argument instantiation and substitution into
694      // template parameters with arguments for prior parameters may or may
695      // not be a SFINAE context; look further up the stack.
696      break;
697
698    case ActiveTemplateInstantiation::ExplicitTemplateArgumentSubstitution:
699    case ActiveTemplateInstantiation::DeducedTemplateArgumentSubstitution:
700      // We're either substitution explicitly-specified template arguments
701      // or deduced template arguments, so SFINAE applies.
702      assert(Active->DeductionInfo && "Missing deduction info pointer");
703      return Active->DeductionInfo;
704    }
705  }
706
707  return None;
708}
709
710/// \brief Retrieve the depth and index of a parameter pack.
711static std::pair<unsigned, unsigned>
712getDepthAndIndex(NamedDecl *ND) {
713  if (TemplateTypeParmDecl *TTP = dyn_cast<TemplateTypeParmDecl>(ND))
714    return std::make_pair(TTP->getDepth(), TTP->getIndex());
715
716  if (NonTypeTemplateParmDecl *NTTP = dyn_cast<NonTypeTemplateParmDecl>(ND))
717    return std::make_pair(NTTP->getDepth(), NTTP->getIndex());
718
719  TemplateTemplateParmDecl *TTP = cast<TemplateTemplateParmDecl>(ND);
720  return std::make_pair(TTP->getDepth(), TTP->getIndex());
721}
722
723//===----------------------------------------------------------------------===/
724// Template Instantiation for Types
725//===----------------------------------------------------------------------===/
726namespace {
727  class TemplateInstantiator : public TreeTransform<TemplateInstantiator> {
728    const MultiLevelTemplateArgumentList &TemplateArgs;
729    SourceLocation Loc;
730    DeclarationName Entity;
731
732  public:
733    typedef TreeTransform<TemplateInstantiator> inherited;
734
735    TemplateInstantiator(Sema &SemaRef,
736                         const MultiLevelTemplateArgumentList &TemplateArgs,
737                         SourceLocation Loc,
738                         DeclarationName Entity)
739      : inherited(SemaRef), TemplateArgs(TemplateArgs), Loc(Loc),
740        Entity(Entity) { }
741
742    /// \brief Determine whether the given type \p T has already been
743    /// transformed.
744    ///
745    /// For the purposes of template instantiation, a type has already been
746    /// transformed if it is NULL or if it is not dependent.
747    bool AlreadyTransformed(QualType T);
748
749    /// \brief Returns the location of the entity being instantiated, if known.
750    SourceLocation getBaseLocation() { return Loc; }
751
752    /// \brief Returns the name of the entity being instantiated, if any.
753    DeclarationName getBaseEntity() { return Entity; }
754
755    /// \brief Sets the "base" location and entity when that
756    /// information is known based on another transformation.
757    void setBase(SourceLocation Loc, DeclarationName Entity) {
758      this->Loc = Loc;
759      this->Entity = Entity;
760    }
761
762    bool TryExpandParameterPacks(SourceLocation EllipsisLoc,
763                                 SourceRange PatternRange,
764                                 ArrayRef<UnexpandedParameterPack> Unexpanded,
765                                 bool &ShouldExpand, bool &RetainExpansion,
766                                 Optional<unsigned> &NumExpansions) {
767      return getSema().CheckParameterPacksForExpansion(EllipsisLoc,
768                                                       PatternRange, Unexpanded,
769                                                       TemplateArgs,
770                                                       ShouldExpand,
771                                                       RetainExpansion,
772                                                       NumExpansions);
773    }
774
775    void ExpandingFunctionParameterPack(ParmVarDecl *Pack) {
776      SemaRef.CurrentInstantiationScope->MakeInstantiatedLocalArgPack(Pack);
777    }
778
779    TemplateArgument ForgetPartiallySubstitutedPack() {
780      TemplateArgument Result;
781      if (NamedDecl *PartialPack
782            = SemaRef.CurrentInstantiationScope->getPartiallySubstitutedPack()){
783        MultiLevelTemplateArgumentList &TemplateArgs
784          = const_cast<MultiLevelTemplateArgumentList &>(this->TemplateArgs);
785        unsigned Depth, Index;
786        llvm::tie(Depth, Index) = getDepthAndIndex(PartialPack);
787        if (TemplateArgs.hasTemplateArgument(Depth, Index)) {
788          Result = TemplateArgs(Depth, Index);
789          TemplateArgs.setArgument(Depth, Index, TemplateArgument());
790        }
791      }
792
793      return Result;
794    }
795
796    void RememberPartiallySubstitutedPack(TemplateArgument Arg) {
797      if (Arg.isNull())
798        return;
799
800      if (NamedDecl *PartialPack
801            = SemaRef.CurrentInstantiationScope->getPartiallySubstitutedPack()){
802        MultiLevelTemplateArgumentList &TemplateArgs
803        = const_cast<MultiLevelTemplateArgumentList &>(this->TemplateArgs);
804        unsigned Depth, Index;
805        llvm::tie(Depth, Index) = getDepthAndIndex(PartialPack);
806        TemplateArgs.setArgument(Depth, Index, Arg);
807      }
808    }
809
810    /// \brief Transform the given declaration by instantiating a reference to
811    /// this declaration.
812    Decl *TransformDecl(SourceLocation Loc, Decl *D);
813
814    void transformAttrs(Decl *Old, Decl *New) {
815      SemaRef.InstantiateAttrs(TemplateArgs, Old, New);
816    }
817
818    void transformedLocalDecl(Decl *Old, Decl *New) {
819      SemaRef.CurrentInstantiationScope->InstantiatedLocal(Old, New);
820    }
821
822    /// \brief Transform the definition of the given declaration by
823    /// instantiating it.
824    Decl *TransformDefinition(SourceLocation Loc, Decl *D);
825
826    /// \brief Transform the first qualifier within a scope by instantiating the
827    /// declaration.
828    NamedDecl *TransformFirstQualifierInScope(NamedDecl *D, SourceLocation Loc);
829
830    /// \brief Rebuild the exception declaration and register the declaration
831    /// as an instantiated local.
832    VarDecl *RebuildExceptionDecl(VarDecl *ExceptionDecl,
833                                  TypeSourceInfo *Declarator,
834                                  SourceLocation StartLoc,
835                                  SourceLocation NameLoc,
836                                  IdentifierInfo *Name);
837
838    /// \brief Rebuild the Objective-C exception declaration and register the
839    /// declaration as an instantiated local.
840    VarDecl *RebuildObjCExceptionDecl(VarDecl *ExceptionDecl,
841                                      TypeSourceInfo *TSInfo, QualType T);
842
843    /// \brief Check for tag mismatches when instantiating an
844    /// elaborated type.
845    QualType RebuildElaboratedType(SourceLocation KeywordLoc,
846                                   ElaboratedTypeKeyword Keyword,
847                                   NestedNameSpecifierLoc QualifierLoc,
848                                   QualType T);
849
850    TemplateName TransformTemplateName(CXXScopeSpec &SS,
851                                       TemplateName Name,
852                                       SourceLocation NameLoc,
853                                       QualType ObjectType = QualType(),
854                                       NamedDecl *FirstQualifierInScope = 0);
855
856    ExprResult TransformPredefinedExpr(PredefinedExpr *E);
857    ExprResult TransformDeclRefExpr(DeclRefExpr *E);
858    ExprResult TransformCXXDefaultArgExpr(CXXDefaultArgExpr *E);
859
860    ExprResult TransformTemplateParmRefExpr(DeclRefExpr *E,
861                                            NonTypeTemplateParmDecl *D);
862    ExprResult TransformSubstNonTypeTemplateParmPackExpr(
863                                           SubstNonTypeTemplateParmPackExpr *E);
864
865    /// \brief Rebuild a DeclRefExpr for a ParmVarDecl reference.
866    ExprResult RebuildParmVarDeclRefExpr(ParmVarDecl *PD, SourceLocation Loc);
867
868    /// \brief Transform a reference to a function parameter pack.
869    ExprResult TransformFunctionParmPackRefExpr(DeclRefExpr *E,
870                                                ParmVarDecl *PD);
871
872    /// \brief Transform a FunctionParmPackExpr which was built when we couldn't
873    /// expand a function parameter pack reference which refers to an expanded
874    /// pack.
875    ExprResult TransformFunctionParmPackExpr(FunctionParmPackExpr *E);
876
877    QualType TransformFunctionProtoType(TypeLocBuilder &TLB,
878                                        FunctionProtoTypeLoc TL);
879    QualType TransformFunctionProtoType(TypeLocBuilder &TLB,
880                                        FunctionProtoTypeLoc TL,
881                                        CXXRecordDecl *ThisContext,
882                                        unsigned ThisTypeQuals);
883
884    ParmVarDecl *TransformFunctionTypeParam(ParmVarDecl *OldParm,
885                                            int indexAdjustment,
886                                            Optional<unsigned> NumExpansions,
887                                            bool ExpectParameterPack);
888
889    /// \brief Transforms a template type parameter type by performing
890    /// substitution of the corresponding template type argument.
891    QualType TransformTemplateTypeParmType(TypeLocBuilder &TLB,
892                                           TemplateTypeParmTypeLoc TL);
893
894    /// \brief Transforms an already-substituted template type parameter pack
895    /// into either itself (if we aren't substituting into its pack expansion)
896    /// or the appropriate substituted argument.
897    QualType TransformSubstTemplateTypeParmPackType(TypeLocBuilder &TLB,
898                                           SubstTemplateTypeParmPackTypeLoc TL);
899
900    ExprResult TransformCallExpr(CallExpr *CE) {
901      getSema().CallsUndergoingInstantiation.push_back(CE);
902      ExprResult Result =
903          TreeTransform<TemplateInstantiator>::TransformCallExpr(CE);
904      getSema().CallsUndergoingInstantiation.pop_back();
905      return Result;
906    }
907
908    ExprResult TransformLambdaExpr(LambdaExpr *E) {
909      LocalInstantiationScope Scope(SemaRef, /*CombineWithOuterScope=*/true);
910      return TreeTransform<TemplateInstantiator>::TransformLambdaExpr(E);
911    }
912
913    ExprResult TransformLambdaScope(LambdaExpr *E,
914                                    CXXMethodDecl *CallOperator) {
915      CallOperator->setInstantiationOfMemberFunction(E->getCallOperator(),
916                                                     TSK_ImplicitInstantiation);
917      return TreeTransform<TemplateInstantiator>::
918         TransformLambdaScope(E, CallOperator);
919    }
920
921  private:
922    ExprResult transformNonTypeTemplateParmRef(NonTypeTemplateParmDecl *parm,
923                                               SourceLocation loc,
924                                               TemplateArgument arg);
925  };
926}
927
928bool TemplateInstantiator::AlreadyTransformed(QualType T) {
929  if (T.isNull())
930    return true;
931
932  if (T->isInstantiationDependentType() || T->isVariablyModifiedType())
933    return false;
934
935  getSema().MarkDeclarationsReferencedInType(Loc, T);
936  return true;
937}
938
939static TemplateArgument
940getPackSubstitutedTemplateArgument(Sema &S, TemplateArgument Arg) {
941  assert(S.ArgumentPackSubstitutionIndex >= 0);
942  assert(S.ArgumentPackSubstitutionIndex < (int)Arg.pack_size());
943  Arg = Arg.pack_begin()[S.ArgumentPackSubstitutionIndex];
944  if (Arg.isPackExpansion())
945    Arg = Arg.getPackExpansionPattern();
946  return Arg;
947}
948
949Decl *TemplateInstantiator::TransformDecl(SourceLocation Loc, Decl *D) {
950  if (!D)
951    return 0;
952
953  if (TemplateTemplateParmDecl *TTP = dyn_cast<TemplateTemplateParmDecl>(D)) {
954    if (TTP->getDepth() < TemplateArgs.getNumLevels()) {
955      // If the corresponding template argument is NULL or non-existent, it's
956      // because we are performing instantiation from explicitly-specified
957      // template arguments in a function template, but there were some
958      // arguments left unspecified.
959      if (!TemplateArgs.hasTemplateArgument(TTP->getDepth(),
960                                            TTP->getPosition()))
961        return D;
962
963      TemplateArgument Arg = TemplateArgs(TTP->getDepth(), TTP->getPosition());
964
965      if (TTP->isParameterPack()) {
966        assert(Arg.getKind() == TemplateArgument::Pack &&
967               "Missing argument pack");
968        Arg = getPackSubstitutedTemplateArgument(getSema(), Arg);
969      }
970
971      TemplateName Template = Arg.getAsTemplate();
972      assert(!Template.isNull() && Template.getAsTemplateDecl() &&
973             "Wrong kind of template template argument");
974      return Template.getAsTemplateDecl();
975    }
976
977    // Fall through to find the instantiated declaration for this template
978    // template parameter.
979  }
980
981  return SemaRef.FindInstantiatedDecl(Loc, cast<NamedDecl>(D), TemplateArgs);
982}
983
984Decl *TemplateInstantiator::TransformDefinition(SourceLocation Loc, Decl *D) {
985  Decl *Inst = getSema().SubstDecl(D, getSema().CurContext, TemplateArgs);
986  if (!Inst)
987    return 0;
988
989  getSema().CurrentInstantiationScope->InstantiatedLocal(D, Inst);
990  return Inst;
991}
992
993NamedDecl *
994TemplateInstantiator::TransformFirstQualifierInScope(NamedDecl *D,
995                                                     SourceLocation Loc) {
996  // If the first part of the nested-name-specifier was a template type
997  // parameter, instantiate that type parameter down to a tag type.
998  if (TemplateTypeParmDecl *TTPD = dyn_cast_or_null<TemplateTypeParmDecl>(D)) {
999    const TemplateTypeParmType *TTP
1000      = cast<TemplateTypeParmType>(getSema().Context.getTypeDeclType(TTPD));
1001
1002    if (TTP->getDepth() < TemplateArgs.getNumLevels()) {
1003      // FIXME: This needs testing w/ member access expressions.
1004      TemplateArgument Arg = TemplateArgs(TTP->getDepth(), TTP->getIndex());
1005
1006      if (TTP->isParameterPack()) {
1007        assert(Arg.getKind() == TemplateArgument::Pack &&
1008               "Missing argument pack");
1009
1010        if (getSema().ArgumentPackSubstitutionIndex == -1)
1011          return 0;
1012
1013        Arg = getPackSubstitutedTemplateArgument(getSema(), Arg);
1014      }
1015
1016      QualType T = Arg.getAsType();
1017      if (T.isNull())
1018        return cast_or_null<NamedDecl>(TransformDecl(Loc, D));
1019
1020      if (const TagType *Tag = T->getAs<TagType>())
1021        return Tag->getDecl();
1022
1023      // The resulting type is not a tag; complain.
1024      getSema().Diag(Loc, diag::err_nested_name_spec_non_tag) << T;
1025      return 0;
1026    }
1027  }
1028
1029  return cast_or_null<NamedDecl>(TransformDecl(Loc, D));
1030}
1031
1032VarDecl *
1033TemplateInstantiator::RebuildExceptionDecl(VarDecl *ExceptionDecl,
1034                                           TypeSourceInfo *Declarator,
1035                                           SourceLocation StartLoc,
1036                                           SourceLocation NameLoc,
1037                                           IdentifierInfo *Name) {
1038  VarDecl *Var = inherited::RebuildExceptionDecl(ExceptionDecl, Declarator,
1039                                                 StartLoc, NameLoc, Name);
1040  if (Var)
1041    getSema().CurrentInstantiationScope->InstantiatedLocal(ExceptionDecl, Var);
1042  return Var;
1043}
1044
1045VarDecl *TemplateInstantiator::RebuildObjCExceptionDecl(VarDecl *ExceptionDecl,
1046                                                        TypeSourceInfo *TSInfo,
1047                                                        QualType T) {
1048  VarDecl *Var = inherited::RebuildObjCExceptionDecl(ExceptionDecl, TSInfo, T);
1049  if (Var)
1050    getSema().CurrentInstantiationScope->InstantiatedLocal(ExceptionDecl, Var);
1051  return Var;
1052}
1053
1054QualType
1055TemplateInstantiator::RebuildElaboratedType(SourceLocation KeywordLoc,
1056                                            ElaboratedTypeKeyword Keyword,
1057                                            NestedNameSpecifierLoc QualifierLoc,
1058                                            QualType T) {
1059  if (const TagType *TT = T->getAs<TagType>()) {
1060    TagDecl* TD = TT->getDecl();
1061
1062    SourceLocation TagLocation = KeywordLoc;
1063
1064    IdentifierInfo *Id = TD->getIdentifier();
1065
1066    // TODO: should we even warn on struct/class mismatches for this?  Seems
1067    // like it's likely to produce a lot of spurious errors.
1068    if (Id && Keyword != ETK_None && Keyword != ETK_Typename) {
1069      TagTypeKind Kind = TypeWithKeyword::getTagTypeKindForKeyword(Keyword);
1070      if (!SemaRef.isAcceptableTagRedeclaration(TD, Kind, /*isDefinition*/false,
1071                                                TagLocation, *Id)) {
1072        SemaRef.Diag(TagLocation, diag::err_use_with_wrong_tag)
1073          << Id
1074          << FixItHint::CreateReplacement(SourceRange(TagLocation),
1075                                          TD->getKindName());
1076        SemaRef.Diag(TD->getLocation(), diag::note_previous_use);
1077      }
1078    }
1079  }
1080
1081  return TreeTransform<TemplateInstantiator>::RebuildElaboratedType(KeywordLoc,
1082                                                                    Keyword,
1083                                                                  QualifierLoc,
1084                                                                    T);
1085}
1086
1087TemplateName TemplateInstantiator::TransformTemplateName(CXXScopeSpec &SS,
1088                                                         TemplateName Name,
1089                                                         SourceLocation NameLoc,
1090                                                         QualType ObjectType,
1091                                             NamedDecl *FirstQualifierInScope) {
1092  if (TemplateTemplateParmDecl *TTP
1093       = dyn_cast_or_null<TemplateTemplateParmDecl>(Name.getAsTemplateDecl())) {
1094    if (TTP->getDepth() < TemplateArgs.getNumLevels()) {
1095      // If the corresponding template argument is NULL or non-existent, it's
1096      // because we are performing instantiation from explicitly-specified
1097      // template arguments in a function template, but there were some
1098      // arguments left unspecified.
1099      if (!TemplateArgs.hasTemplateArgument(TTP->getDepth(),
1100                                            TTP->getPosition()))
1101        return Name;
1102
1103      TemplateArgument Arg = TemplateArgs(TTP->getDepth(), TTP->getPosition());
1104
1105      if (TTP->isParameterPack()) {
1106        assert(Arg.getKind() == TemplateArgument::Pack &&
1107               "Missing argument pack");
1108
1109        if (getSema().ArgumentPackSubstitutionIndex == -1) {
1110          // We have the template argument pack to substitute, but we're not
1111          // actually expanding the enclosing pack expansion yet. So, just
1112          // keep the entire argument pack.
1113          return getSema().Context.getSubstTemplateTemplateParmPack(TTP, Arg);
1114        }
1115
1116        Arg = getPackSubstitutedTemplateArgument(getSema(), Arg);
1117      }
1118
1119      TemplateName Template = Arg.getAsTemplate();
1120      assert(!Template.isNull() && "Null template template argument");
1121
1122      // We don't ever want to substitute for a qualified template name, since
1123      // the qualifier is handled separately. So, look through the qualified
1124      // template name to its underlying declaration.
1125      if (QualifiedTemplateName *QTN = Template.getAsQualifiedTemplateName())
1126        Template = TemplateName(QTN->getTemplateDecl());
1127
1128      Template = getSema().Context.getSubstTemplateTemplateParm(TTP, Template);
1129      return Template;
1130    }
1131  }
1132
1133  if (SubstTemplateTemplateParmPackStorage *SubstPack
1134      = Name.getAsSubstTemplateTemplateParmPack()) {
1135    if (getSema().ArgumentPackSubstitutionIndex == -1)
1136      return Name;
1137
1138    TemplateArgument Arg = SubstPack->getArgumentPack();
1139    Arg = getPackSubstitutedTemplateArgument(getSema(), Arg);
1140    return Arg.getAsTemplate();
1141  }
1142
1143  return inherited::TransformTemplateName(SS, Name, NameLoc, ObjectType,
1144                                          FirstQualifierInScope);
1145}
1146
1147ExprResult
1148TemplateInstantiator::TransformPredefinedExpr(PredefinedExpr *E) {
1149  if (!E->isTypeDependent())
1150    return SemaRef.Owned(E);
1151
1152  return getSema().BuildPredefinedExpr(E->getLocation(), E->getIdentType());
1153}
1154
1155ExprResult
1156TemplateInstantiator::TransformTemplateParmRefExpr(DeclRefExpr *E,
1157                                               NonTypeTemplateParmDecl *NTTP) {
1158  // If the corresponding template argument is NULL or non-existent, it's
1159  // because we are performing instantiation from explicitly-specified
1160  // template arguments in a function template, but there were some
1161  // arguments left unspecified.
1162  if (!TemplateArgs.hasTemplateArgument(NTTP->getDepth(),
1163                                        NTTP->getPosition()))
1164    return SemaRef.Owned(E);
1165
1166  TemplateArgument Arg = TemplateArgs(NTTP->getDepth(), NTTP->getPosition());
1167  if (NTTP->isParameterPack()) {
1168    assert(Arg.getKind() == TemplateArgument::Pack &&
1169           "Missing argument pack");
1170
1171    if (getSema().ArgumentPackSubstitutionIndex == -1) {
1172      // We have an argument pack, but we can't select a particular argument
1173      // out of it yet. Therefore, we'll build an expression to hold on to that
1174      // argument pack.
1175      QualType TargetType = SemaRef.SubstType(NTTP->getType(), TemplateArgs,
1176                                              E->getLocation(),
1177                                              NTTP->getDeclName());
1178      if (TargetType.isNull())
1179        return ExprError();
1180
1181      return new (SemaRef.Context) SubstNonTypeTemplateParmPackExpr(TargetType,
1182                                                                    NTTP,
1183                                                              E->getLocation(),
1184                                                                    Arg);
1185    }
1186
1187    Arg = getPackSubstitutedTemplateArgument(getSema(), Arg);
1188  }
1189
1190  return transformNonTypeTemplateParmRef(NTTP, E->getLocation(), Arg);
1191}
1192
1193ExprResult TemplateInstantiator::transformNonTypeTemplateParmRef(
1194                                                 NonTypeTemplateParmDecl *parm,
1195                                                 SourceLocation loc,
1196                                                 TemplateArgument arg) {
1197  ExprResult result;
1198  QualType type;
1199
1200  // The template argument itself might be an expression, in which
1201  // case we just return that expression.
1202  if (arg.getKind() == TemplateArgument::Expression) {
1203    Expr *argExpr = arg.getAsExpr();
1204    result = SemaRef.Owned(argExpr);
1205    type = argExpr->getType();
1206
1207  } else if (arg.getKind() == TemplateArgument::Declaration ||
1208             arg.getKind() == TemplateArgument::NullPtr) {
1209    ValueDecl *VD;
1210    if (arg.getKind() == TemplateArgument::Declaration) {
1211      VD = cast<ValueDecl>(arg.getAsDecl());
1212
1213      // Find the instantiation of the template argument.  This is
1214      // required for nested templates.
1215      VD = cast_or_null<ValueDecl>(
1216             getSema().FindInstantiatedDecl(loc, VD, TemplateArgs));
1217      if (!VD)
1218        return ExprError();
1219    } else {
1220      // Propagate NULL template argument.
1221      VD = 0;
1222    }
1223
1224    // Derive the type we want the substituted decl to have.  This had
1225    // better be non-dependent, or these checks will have serious problems.
1226    if (parm->isExpandedParameterPack()) {
1227      type = parm->getExpansionType(SemaRef.ArgumentPackSubstitutionIndex);
1228    } else if (parm->isParameterPack() &&
1229               isa<PackExpansionType>(parm->getType())) {
1230      type = SemaRef.SubstType(
1231                        cast<PackExpansionType>(parm->getType())->getPattern(),
1232                                     TemplateArgs, loc, parm->getDeclName());
1233    } else {
1234      type = SemaRef.SubstType(parm->getType(), TemplateArgs,
1235                               loc, parm->getDeclName());
1236    }
1237    assert(!type.isNull() && "type substitution failed for param type");
1238    assert(!type->isDependentType() && "param type still dependent");
1239    result = SemaRef.BuildExpressionFromDeclTemplateArgument(arg, type, loc);
1240
1241    if (!result.isInvalid()) type = result.get()->getType();
1242  } else {
1243    result = SemaRef.BuildExpressionFromIntegralTemplateArgument(arg, loc);
1244
1245    // Note that this type can be different from the type of 'result',
1246    // e.g. if it's an enum type.
1247    type = arg.getIntegralType();
1248  }
1249  if (result.isInvalid()) return ExprError();
1250
1251  Expr *resultExpr = result.take();
1252  return SemaRef.Owned(new (SemaRef.Context)
1253                SubstNonTypeTemplateParmExpr(type,
1254                                             resultExpr->getValueKind(),
1255                                             loc, parm, resultExpr));
1256}
1257
1258ExprResult
1259TemplateInstantiator::TransformSubstNonTypeTemplateParmPackExpr(
1260                                          SubstNonTypeTemplateParmPackExpr *E) {
1261  if (getSema().ArgumentPackSubstitutionIndex == -1) {
1262    // We aren't expanding the parameter pack, so just return ourselves.
1263    return getSema().Owned(E);
1264  }
1265
1266  TemplateArgument Arg = E->getArgumentPack();
1267  Arg = getPackSubstitutedTemplateArgument(getSema(), Arg);
1268  return transformNonTypeTemplateParmRef(E->getParameterPack(),
1269                                         E->getParameterPackLocation(),
1270                                         Arg);
1271}
1272
1273ExprResult
1274TemplateInstantiator::RebuildParmVarDeclRefExpr(ParmVarDecl *PD,
1275                                                SourceLocation Loc) {
1276  DeclarationNameInfo NameInfo(PD->getDeclName(), Loc);
1277  return getSema().BuildDeclarationNameExpr(CXXScopeSpec(), NameInfo, PD);
1278}
1279
1280ExprResult
1281TemplateInstantiator::TransformFunctionParmPackExpr(FunctionParmPackExpr *E) {
1282  if (getSema().ArgumentPackSubstitutionIndex != -1) {
1283    // We can expand this parameter pack now.
1284    ParmVarDecl *D = E->getExpansion(getSema().ArgumentPackSubstitutionIndex);
1285    ValueDecl *VD = cast_or_null<ValueDecl>(TransformDecl(E->getExprLoc(), D));
1286    if (!VD)
1287      return ExprError();
1288    return RebuildParmVarDeclRefExpr(cast<ParmVarDecl>(VD), E->getExprLoc());
1289  }
1290
1291  QualType T = TransformType(E->getType());
1292  if (T.isNull())
1293    return ExprError();
1294
1295  // Transform each of the parameter expansions into the corresponding
1296  // parameters in the instantiation of the function decl.
1297  SmallVector<Decl *, 8> Parms;
1298  Parms.reserve(E->getNumExpansions());
1299  for (FunctionParmPackExpr::iterator I = E->begin(), End = E->end();
1300       I != End; ++I) {
1301    ParmVarDecl *D =
1302        cast_or_null<ParmVarDecl>(TransformDecl(E->getExprLoc(), *I));
1303    if (!D)
1304      return ExprError();
1305    Parms.push_back(D);
1306  }
1307
1308  return FunctionParmPackExpr::Create(getSema().Context, T,
1309                                      E->getParameterPack(),
1310                                      E->getParameterPackLocation(), Parms);
1311}
1312
1313ExprResult
1314TemplateInstantiator::TransformFunctionParmPackRefExpr(DeclRefExpr *E,
1315                                                       ParmVarDecl *PD) {
1316  typedef LocalInstantiationScope::DeclArgumentPack DeclArgumentPack;
1317  llvm::PointerUnion<Decl *, DeclArgumentPack *> *Found
1318    = getSema().CurrentInstantiationScope->findInstantiationOf(PD);
1319  assert(Found && "no instantiation for parameter pack");
1320
1321  Decl *TransformedDecl;
1322  if (DeclArgumentPack *Pack = Found->dyn_cast<DeclArgumentPack *>()) {
1323    // If this is a reference to a function parameter pack which we can substitute
1324    // but can't yet expand, build a FunctionParmPackExpr for it.
1325    if (getSema().ArgumentPackSubstitutionIndex == -1) {
1326      QualType T = TransformType(E->getType());
1327      if (T.isNull())
1328        return ExprError();
1329      return FunctionParmPackExpr::Create(getSema().Context, T, PD,
1330                                          E->getExprLoc(), *Pack);
1331    }
1332
1333    TransformedDecl = (*Pack)[getSema().ArgumentPackSubstitutionIndex];
1334  } else {
1335    TransformedDecl = Found->get<Decl*>();
1336  }
1337
1338  // We have either an unexpanded pack or a specific expansion.
1339  return RebuildParmVarDeclRefExpr(cast<ParmVarDecl>(TransformedDecl),
1340                                   E->getExprLoc());
1341}
1342
1343ExprResult
1344TemplateInstantiator::TransformDeclRefExpr(DeclRefExpr *E) {
1345  NamedDecl *D = E->getDecl();
1346
1347  // Handle references to non-type template parameters and non-type template
1348  // parameter packs.
1349  if (NonTypeTemplateParmDecl *NTTP = dyn_cast<NonTypeTemplateParmDecl>(D)) {
1350    if (NTTP->getDepth() < TemplateArgs.getNumLevels())
1351      return TransformTemplateParmRefExpr(E, NTTP);
1352
1353    // We have a non-type template parameter that isn't fully substituted;
1354    // FindInstantiatedDecl will find it in the local instantiation scope.
1355  }
1356
1357  // Handle references to function parameter packs.
1358  if (ParmVarDecl *PD = dyn_cast<ParmVarDecl>(D))
1359    if (PD->isParameterPack())
1360      return TransformFunctionParmPackRefExpr(E, PD);
1361
1362  return TreeTransform<TemplateInstantiator>::TransformDeclRefExpr(E);
1363}
1364
1365ExprResult TemplateInstantiator::TransformCXXDefaultArgExpr(
1366    CXXDefaultArgExpr *E) {
1367  assert(!cast<FunctionDecl>(E->getParam()->getDeclContext())->
1368             getDescribedFunctionTemplate() &&
1369         "Default arg expressions are never formed in dependent cases.");
1370  return SemaRef.BuildCXXDefaultArgExpr(E->getUsedLocation(),
1371                           cast<FunctionDecl>(E->getParam()->getDeclContext()),
1372                                        E->getParam());
1373}
1374
1375QualType TemplateInstantiator::TransformFunctionProtoType(TypeLocBuilder &TLB,
1376                                                      FunctionProtoTypeLoc TL) {
1377  // We need a local instantiation scope for this function prototype.
1378  LocalInstantiationScope Scope(SemaRef, /*CombineWithOuterScope=*/true);
1379  return inherited::TransformFunctionProtoType(TLB, TL);
1380}
1381
1382QualType TemplateInstantiator::TransformFunctionProtoType(TypeLocBuilder &TLB,
1383                                 FunctionProtoTypeLoc TL,
1384                                 CXXRecordDecl *ThisContext,
1385                                 unsigned ThisTypeQuals) {
1386  // We need a local instantiation scope for this function prototype.
1387  LocalInstantiationScope Scope(SemaRef, /*CombineWithOuterScope=*/true);
1388  return inherited::TransformFunctionProtoType(TLB, TL, ThisContext,
1389                                               ThisTypeQuals);
1390}
1391
1392ParmVarDecl *
1393TemplateInstantiator::TransformFunctionTypeParam(ParmVarDecl *OldParm,
1394                                                 int indexAdjustment,
1395                                               Optional<unsigned> NumExpansions,
1396                                                 bool ExpectParameterPack) {
1397  return SemaRef.SubstParmVarDecl(OldParm, TemplateArgs, indexAdjustment,
1398                                  NumExpansions, ExpectParameterPack);
1399}
1400
1401QualType
1402TemplateInstantiator::TransformTemplateTypeParmType(TypeLocBuilder &TLB,
1403                                                TemplateTypeParmTypeLoc TL) {
1404  const TemplateTypeParmType *T = TL.getTypePtr();
1405  if (T->getDepth() < TemplateArgs.getNumLevels()) {
1406    // Replace the template type parameter with its corresponding
1407    // template argument.
1408
1409    // If the corresponding template argument is NULL or doesn't exist, it's
1410    // because we are performing instantiation from explicitly-specified
1411    // template arguments in a function template class, but there were some
1412    // arguments left unspecified.
1413    if (!TemplateArgs.hasTemplateArgument(T->getDepth(), T->getIndex())) {
1414      TemplateTypeParmTypeLoc NewTL
1415        = TLB.push<TemplateTypeParmTypeLoc>(TL.getType());
1416      NewTL.setNameLoc(TL.getNameLoc());
1417      return TL.getType();
1418    }
1419
1420    TemplateArgument Arg = TemplateArgs(T->getDepth(), T->getIndex());
1421
1422    if (T->isParameterPack()) {
1423      assert(Arg.getKind() == TemplateArgument::Pack &&
1424             "Missing argument pack");
1425
1426      if (getSema().ArgumentPackSubstitutionIndex == -1) {
1427        // We have the template argument pack, but we're not expanding the
1428        // enclosing pack expansion yet. Just save the template argument
1429        // pack for later substitution.
1430        QualType Result
1431          = getSema().Context.getSubstTemplateTypeParmPackType(T, Arg);
1432        SubstTemplateTypeParmPackTypeLoc NewTL
1433          = TLB.push<SubstTemplateTypeParmPackTypeLoc>(Result);
1434        NewTL.setNameLoc(TL.getNameLoc());
1435        return Result;
1436      }
1437
1438      Arg = getPackSubstitutedTemplateArgument(getSema(), Arg);
1439    }
1440
1441    assert(Arg.getKind() == TemplateArgument::Type &&
1442           "Template argument kind mismatch");
1443
1444    QualType Replacement = Arg.getAsType();
1445
1446    // TODO: only do this uniquing once, at the start of instantiation.
1447    QualType Result
1448      = getSema().Context.getSubstTemplateTypeParmType(T, Replacement);
1449    SubstTemplateTypeParmTypeLoc NewTL
1450      = TLB.push<SubstTemplateTypeParmTypeLoc>(Result);
1451    NewTL.setNameLoc(TL.getNameLoc());
1452    return Result;
1453  }
1454
1455  // The template type parameter comes from an inner template (e.g.,
1456  // the template parameter list of a member template inside the
1457  // template we are instantiating). Create a new template type
1458  // parameter with the template "level" reduced by one.
1459  TemplateTypeParmDecl *NewTTPDecl = 0;
1460  if (TemplateTypeParmDecl *OldTTPDecl = T->getDecl())
1461    NewTTPDecl = cast_or_null<TemplateTypeParmDecl>(
1462                                  TransformDecl(TL.getNameLoc(), OldTTPDecl));
1463
1464  QualType Result
1465    = getSema().Context.getTemplateTypeParmType(T->getDepth()
1466                                                 - TemplateArgs.getNumLevels(),
1467                                                T->getIndex(),
1468                                                T->isParameterPack(),
1469                                                NewTTPDecl);
1470  TemplateTypeParmTypeLoc NewTL = TLB.push<TemplateTypeParmTypeLoc>(Result);
1471  NewTL.setNameLoc(TL.getNameLoc());
1472  return Result;
1473}
1474
1475QualType
1476TemplateInstantiator::TransformSubstTemplateTypeParmPackType(
1477                                                            TypeLocBuilder &TLB,
1478                                         SubstTemplateTypeParmPackTypeLoc TL) {
1479  if (getSema().ArgumentPackSubstitutionIndex == -1) {
1480    // We aren't expanding the parameter pack, so just return ourselves.
1481    SubstTemplateTypeParmPackTypeLoc NewTL
1482      = TLB.push<SubstTemplateTypeParmPackTypeLoc>(TL.getType());
1483    NewTL.setNameLoc(TL.getNameLoc());
1484    return TL.getType();
1485  }
1486
1487  TemplateArgument Arg = TL.getTypePtr()->getArgumentPack();
1488  Arg = getPackSubstitutedTemplateArgument(getSema(), Arg);
1489  QualType Result = Arg.getAsType();
1490
1491  Result = getSema().Context.getSubstTemplateTypeParmType(
1492                                      TL.getTypePtr()->getReplacedParameter(),
1493                                                          Result);
1494  SubstTemplateTypeParmTypeLoc NewTL
1495    = TLB.push<SubstTemplateTypeParmTypeLoc>(Result);
1496  NewTL.setNameLoc(TL.getNameLoc());
1497  return Result;
1498}
1499
1500/// \brief Perform substitution on the type T with a given set of template
1501/// arguments.
1502///
1503/// This routine substitutes the given template arguments into the
1504/// type T and produces the instantiated type.
1505///
1506/// \param T the type into which the template arguments will be
1507/// substituted. If this type is not dependent, it will be returned
1508/// immediately.
1509///
1510/// \param Args the template arguments that will be
1511/// substituted for the top-level template parameters within T.
1512///
1513/// \param Loc the location in the source code where this substitution
1514/// is being performed. It will typically be the location of the
1515/// declarator (if we're instantiating the type of some declaration)
1516/// or the location of the type in the source code (if, e.g., we're
1517/// instantiating the type of a cast expression).
1518///
1519/// \param Entity the name of the entity associated with a declaration
1520/// being instantiated (if any). May be empty to indicate that there
1521/// is no such entity (if, e.g., this is a type that occurs as part of
1522/// a cast expression) or that the entity has no name (e.g., an
1523/// unnamed function parameter).
1524///
1525/// \returns If the instantiation succeeds, the instantiated
1526/// type. Otherwise, produces diagnostics and returns a NULL type.
1527TypeSourceInfo *Sema::SubstType(TypeSourceInfo *T,
1528                                const MultiLevelTemplateArgumentList &Args,
1529                                SourceLocation Loc,
1530                                DeclarationName Entity) {
1531  assert(!ActiveTemplateInstantiations.empty() &&
1532         "Cannot perform an instantiation without some context on the "
1533         "instantiation stack");
1534
1535  if (!T->getType()->isInstantiationDependentType() &&
1536      !T->getType()->isVariablyModifiedType())
1537    return T;
1538
1539  TemplateInstantiator Instantiator(*this, Args, Loc, Entity);
1540  return Instantiator.TransformType(T);
1541}
1542
1543TypeSourceInfo *Sema::SubstType(TypeLoc TL,
1544                                const MultiLevelTemplateArgumentList &Args,
1545                                SourceLocation Loc,
1546                                DeclarationName Entity) {
1547  assert(!ActiveTemplateInstantiations.empty() &&
1548         "Cannot perform an instantiation without some context on the "
1549         "instantiation stack");
1550
1551  if (TL.getType().isNull())
1552    return 0;
1553
1554  if (!TL.getType()->isInstantiationDependentType() &&
1555      !TL.getType()->isVariablyModifiedType()) {
1556    // FIXME: Make a copy of the TypeLoc data here, so that we can
1557    // return a new TypeSourceInfo. Inefficient!
1558    TypeLocBuilder TLB;
1559    TLB.pushFullCopy(TL);
1560    return TLB.getTypeSourceInfo(Context, TL.getType());
1561  }
1562
1563  TemplateInstantiator Instantiator(*this, Args, Loc, Entity);
1564  TypeLocBuilder TLB;
1565  TLB.reserve(TL.getFullDataSize());
1566  QualType Result = Instantiator.TransformType(TLB, TL);
1567  if (Result.isNull())
1568    return 0;
1569
1570  return TLB.getTypeSourceInfo(Context, Result);
1571}
1572
1573/// Deprecated form of the above.
1574QualType Sema::SubstType(QualType T,
1575                         const MultiLevelTemplateArgumentList &TemplateArgs,
1576                         SourceLocation Loc, DeclarationName Entity) {
1577  assert(!ActiveTemplateInstantiations.empty() &&
1578         "Cannot perform an instantiation without some context on the "
1579         "instantiation stack");
1580
1581  // If T is not a dependent type or a variably-modified type, there
1582  // is nothing to do.
1583  if (!T->isInstantiationDependentType() && !T->isVariablyModifiedType())
1584    return T;
1585
1586  TemplateInstantiator Instantiator(*this, TemplateArgs, Loc, Entity);
1587  return Instantiator.TransformType(T);
1588}
1589
1590static bool NeedsInstantiationAsFunctionType(TypeSourceInfo *T) {
1591  if (T->getType()->isInstantiationDependentType() ||
1592      T->getType()->isVariablyModifiedType())
1593    return true;
1594
1595  TypeLoc TL = T->getTypeLoc().IgnoreParens();
1596  if (!TL.getAs<FunctionProtoTypeLoc>())
1597    return false;
1598
1599  FunctionProtoTypeLoc FP = TL.castAs<FunctionProtoTypeLoc>();
1600  for (unsigned I = 0, E = FP.getNumArgs(); I != E; ++I) {
1601    ParmVarDecl *P = FP.getArg(I);
1602
1603    // This must be synthesized from a typedef.
1604    if (!P) continue;
1605
1606    // The parameter's type as written might be dependent even if the
1607    // decayed type was not dependent.
1608    if (TypeSourceInfo *TSInfo = P->getTypeSourceInfo())
1609      if (TSInfo->getType()->isInstantiationDependentType())
1610        return true;
1611
1612    // TODO: currently we always rebuild expressions.  When we
1613    // properly get lazier about this, we should use the same
1614    // logic to avoid rebuilding prototypes here.
1615    if (P->hasDefaultArg())
1616      return true;
1617  }
1618
1619  return false;
1620}
1621
1622/// A form of SubstType intended specifically for instantiating the
1623/// type of a FunctionDecl.  Its purpose is solely to force the
1624/// instantiation of default-argument expressions.
1625TypeSourceInfo *Sema::SubstFunctionDeclType(TypeSourceInfo *T,
1626                                const MultiLevelTemplateArgumentList &Args,
1627                                SourceLocation Loc,
1628                                DeclarationName Entity,
1629                                CXXRecordDecl *ThisContext,
1630                                unsigned ThisTypeQuals) {
1631  assert(!ActiveTemplateInstantiations.empty() &&
1632         "Cannot perform an instantiation without some context on the "
1633         "instantiation stack");
1634
1635  if (!NeedsInstantiationAsFunctionType(T))
1636    return T;
1637
1638  TemplateInstantiator Instantiator(*this, Args, Loc, Entity);
1639
1640  TypeLocBuilder TLB;
1641
1642  TypeLoc TL = T->getTypeLoc();
1643  TLB.reserve(TL.getFullDataSize());
1644
1645  QualType Result;
1646
1647  if (FunctionProtoTypeLoc Proto = TL.getAs<FunctionProtoTypeLoc>()) {
1648    Result = Instantiator.TransformFunctionProtoType(TLB, Proto, ThisContext,
1649                                                     ThisTypeQuals);
1650  } else {
1651    Result = Instantiator.TransformType(TLB, TL);
1652  }
1653  if (Result.isNull())
1654    return 0;
1655
1656  return TLB.getTypeSourceInfo(Context, Result);
1657}
1658
1659ParmVarDecl *Sema::SubstParmVarDecl(ParmVarDecl *OldParm,
1660                            const MultiLevelTemplateArgumentList &TemplateArgs,
1661                                    int indexAdjustment,
1662                                    Optional<unsigned> NumExpansions,
1663                                    bool ExpectParameterPack) {
1664  TypeSourceInfo *OldDI = OldParm->getTypeSourceInfo();
1665  TypeSourceInfo *NewDI = 0;
1666
1667  TypeLoc OldTL = OldDI->getTypeLoc();
1668  if (PackExpansionTypeLoc ExpansionTL = OldTL.getAs<PackExpansionTypeLoc>()) {
1669
1670    // We have a function parameter pack. Substitute into the pattern of the
1671    // expansion.
1672    NewDI = SubstType(ExpansionTL.getPatternLoc(), TemplateArgs,
1673                      OldParm->getLocation(), OldParm->getDeclName());
1674    if (!NewDI)
1675      return 0;
1676
1677    if (NewDI->getType()->containsUnexpandedParameterPack()) {
1678      // We still have unexpanded parameter packs, which means that
1679      // our function parameter is still a function parameter pack.
1680      // Therefore, make its type a pack expansion type.
1681      NewDI = CheckPackExpansion(NewDI, ExpansionTL.getEllipsisLoc(),
1682                                 NumExpansions);
1683    } else if (ExpectParameterPack) {
1684      // We expected to get a parameter pack but didn't (because the type
1685      // itself is not a pack expansion type), so complain. This can occur when
1686      // the substitution goes through an alias template that "loses" the
1687      // pack expansion.
1688      Diag(OldParm->getLocation(),
1689           diag::err_function_parameter_pack_without_parameter_packs)
1690        << NewDI->getType();
1691      return 0;
1692    }
1693  } else {
1694    NewDI = SubstType(OldDI, TemplateArgs, OldParm->getLocation(),
1695                      OldParm->getDeclName());
1696  }
1697
1698  if (!NewDI)
1699    return 0;
1700
1701  if (NewDI->getType()->isVoidType()) {
1702    Diag(OldParm->getLocation(), diag::err_param_with_void_type);
1703    return 0;
1704  }
1705
1706  ParmVarDecl *NewParm = CheckParameter(Context.getTranslationUnitDecl(),
1707                                        OldParm->getInnerLocStart(),
1708                                        OldParm->getLocation(),
1709                                        OldParm->getIdentifier(),
1710                                        NewDI->getType(), NewDI,
1711                                        OldParm->getStorageClass());
1712  if (!NewParm)
1713    return 0;
1714
1715  // Mark the (new) default argument as uninstantiated (if any).
1716  if (OldParm->hasUninstantiatedDefaultArg()) {
1717    Expr *Arg = OldParm->getUninstantiatedDefaultArg();
1718    NewParm->setUninstantiatedDefaultArg(Arg);
1719  } else if (OldParm->hasUnparsedDefaultArg()) {
1720    NewParm->setUnparsedDefaultArg();
1721    UnparsedDefaultArgInstantiations[OldParm].push_back(NewParm);
1722  } else if (Expr *Arg = OldParm->getDefaultArg())
1723    // FIXME: if we non-lazily instantiated non-dependent default args for
1724    // non-dependent parameter types we could remove a bunch of duplicate
1725    // conversion warnings for such arguments.
1726    NewParm->setUninstantiatedDefaultArg(Arg);
1727
1728  NewParm->setHasInheritedDefaultArg(OldParm->hasInheritedDefaultArg());
1729
1730  if (OldParm->isParameterPack() && !NewParm->isParameterPack()) {
1731    // Add the new parameter to the instantiated parameter pack.
1732    CurrentInstantiationScope->InstantiatedLocalPackArg(OldParm, NewParm);
1733  } else {
1734    // Introduce an Old -> New mapping
1735    CurrentInstantiationScope->InstantiatedLocal(OldParm, NewParm);
1736  }
1737
1738  // FIXME: OldParm may come from a FunctionProtoType, in which case CurContext
1739  // can be anything, is this right ?
1740  NewParm->setDeclContext(CurContext);
1741
1742  NewParm->setScopeInfo(OldParm->getFunctionScopeDepth(),
1743                        OldParm->getFunctionScopeIndex() + indexAdjustment);
1744
1745  InstantiateAttrs(TemplateArgs, OldParm, NewParm);
1746
1747  return NewParm;
1748}
1749
1750/// \brief Substitute the given template arguments into the given set of
1751/// parameters, producing the set of parameter types that would be generated
1752/// from such a substitution.
1753bool Sema::SubstParmTypes(SourceLocation Loc,
1754                          ParmVarDecl **Params, unsigned NumParams,
1755                          const MultiLevelTemplateArgumentList &TemplateArgs,
1756                          SmallVectorImpl<QualType> &ParamTypes,
1757                          SmallVectorImpl<ParmVarDecl *> *OutParams) {
1758  assert(!ActiveTemplateInstantiations.empty() &&
1759         "Cannot perform an instantiation without some context on the "
1760         "instantiation stack");
1761
1762  TemplateInstantiator Instantiator(*this, TemplateArgs, Loc,
1763                                    DeclarationName());
1764  return Instantiator.TransformFunctionTypeParams(Loc, Params, NumParams, 0,
1765                                                  ParamTypes, OutParams);
1766}
1767
1768/// \brief Perform substitution on the base class specifiers of the
1769/// given class template specialization.
1770///
1771/// Produces a diagnostic and returns true on error, returns false and
1772/// attaches the instantiated base classes to the class template
1773/// specialization if successful.
1774bool
1775Sema::SubstBaseSpecifiers(CXXRecordDecl *Instantiation,
1776                          CXXRecordDecl *Pattern,
1777                          const MultiLevelTemplateArgumentList &TemplateArgs) {
1778  bool Invalid = false;
1779  SmallVector<CXXBaseSpecifier*, 4> InstantiatedBases;
1780  for (ClassTemplateSpecializationDecl::base_class_iterator
1781         Base = Pattern->bases_begin(), BaseEnd = Pattern->bases_end();
1782       Base != BaseEnd; ++Base) {
1783    if (!Base->getType()->isDependentType()) {
1784      if (const CXXRecordDecl *RD = Base->getType()->getAsCXXRecordDecl()) {
1785        if (RD->isInvalidDecl())
1786          Instantiation->setInvalidDecl();
1787      }
1788      InstantiatedBases.push_back(new (Context) CXXBaseSpecifier(*Base));
1789      continue;
1790    }
1791
1792    SourceLocation EllipsisLoc;
1793    TypeSourceInfo *BaseTypeLoc;
1794    if (Base->isPackExpansion()) {
1795      // This is a pack expansion. See whether we should expand it now, or
1796      // wait until later.
1797      SmallVector<UnexpandedParameterPack, 2> Unexpanded;
1798      collectUnexpandedParameterPacks(Base->getTypeSourceInfo()->getTypeLoc(),
1799                                      Unexpanded);
1800      bool ShouldExpand = false;
1801      bool RetainExpansion = false;
1802      Optional<unsigned> NumExpansions;
1803      if (CheckParameterPacksForExpansion(Base->getEllipsisLoc(),
1804                                          Base->getSourceRange(),
1805                                          Unexpanded,
1806                                          TemplateArgs, ShouldExpand,
1807                                          RetainExpansion,
1808                                          NumExpansions)) {
1809        Invalid = true;
1810        continue;
1811      }
1812
1813      // If we should expand this pack expansion now, do so.
1814      if (ShouldExpand) {
1815        for (unsigned I = 0; I != *NumExpansions; ++I) {
1816            Sema::ArgumentPackSubstitutionIndexRAII SubstIndex(*this, I);
1817
1818          TypeSourceInfo *BaseTypeLoc = SubstType(Base->getTypeSourceInfo(),
1819                                                  TemplateArgs,
1820                                              Base->getSourceRange().getBegin(),
1821                                                  DeclarationName());
1822          if (!BaseTypeLoc) {
1823            Invalid = true;
1824            continue;
1825          }
1826
1827          if (CXXBaseSpecifier *InstantiatedBase
1828                = CheckBaseSpecifier(Instantiation,
1829                                     Base->getSourceRange(),
1830                                     Base->isVirtual(),
1831                                     Base->getAccessSpecifierAsWritten(),
1832                                     BaseTypeLoc,
1833                                     SourceLocation()))
1834            InstantiatedBases.push_back(InstantiatedBase);
1835          else
1836            Invalid = true;
1837        }
1838
1839        continue;
1840      }
1841
1842      // The resulting base specifier will (still) be a pack expansion.
1843      EllipsisLoc = Base->getEllipsisLoc();
1844      Sema::ArgumentPackSubstitutionIndexRAII SubstIndex(*this, -1);
1845      BaseTypeLoc = SubstType(Base->getTypeSourceInfo(),
1846                              TemplateArgs,
1847                              Base->getSourceRange().getBegin(),
1848                              DeclarationName());
1849    } else {
1850      BaseTypeLoc = SubstType(Base->getTypeSourceInfo(),
1851                              TemplateArgs,
1852                              Base->getSourceRange().getBegin(),
1853                              DeclarationName());
1854    }
1855
1856    if (!BaseTypeLoc) {
1857      Invalid = true;
1858      continue;
1859    }
1860
1861    if (CXXBaseSpecifier *InstantiatedBase
1862          = CheckBaseSpecifier(Instantiation,
1863                               Base->getSourceRange(),
1864                               Base->isVirtual(),
1865                               Base->getAccessSpecifierAsWritten(),
1866                               BaseTypeLoc,
1867                               EllipsisLoc))
1868      InstantiatedBases.push_back(InstantiatedBase);
1869    else
1870      Invalid = true;
1871  }
1872
1873  if (!Invalid &&
1874      AttachBaseSpecifiers(Instantiation, InstantiatedBases.data(),
1875                           InstantiatedBases.size()))
1876    Invalid = true;
1877
1878  return Invalid;
1879}
1880
1881// Defined via #include from SemaTemplateInstantiateDecl.cpp
1882namespace clang {
1883  namespace sema {
1884    Attr *instantiateTemplateAttribute(const Attr *At, ASTContext &C, Sema &S,
1885                            const MultiLevelTemplateArgumentList &TemplateArgs);
1886  }
1887}
1888
1889/// Determine whether we would be unable to instantiate this template (because
1890/// it either has no definition, or is in the process of being instantiated).
1891static bool DiagnoseUninstantiableTemplate(Sema &S,
1892                                           SourceLocation PointOfInstantiation,
1893                                           TagDecl *Instantiation,
1894                                           bool InstantiatedFromMember,
1895                                           TagDecl *Pattern,
1896                                           TagDecl *PatternDef,
1897                                           TemplateSpecializationKind TSK,
1898                                           bool Complain = true) {
1899  if (PatternDef && !PatternDef->isBeingDefined())
1900    return false;
1901
1902  if (!Complain || (PatternDef && PatternDef->isInvalidDecl())) {
1903    // Say nothing
1904  } else if (PatternDef) {
1905    assert(PatternDef->isBeingDefined());
1906    S.Diag(PointOfInstantiation,
1907           diag::err_template_instantiate_within_definition)
1908      << (TSK != TSK_ImplicitInstantiation)
1909      << S.Context.getTypeDeclType(Instantiation);
1910    // Not much point in noting the template declaration here, since
1911    // we're lexically inside it.
1912    Instantiation->setInvalidDecl();
1913  } else if (InstantiatedFromMember) {
1914    S.Diag(PointOfInstantiation,
1915           diag::err_implicit_instantiate_member_undefined)
1916      << S.Context.getTypeDeclType(Instantiation);
1917    S.Diag(Pattern->getLocation(), diag::note_member_of_template_here);
1918  } else {
1919    S.Diag(PointOfInstantiation, diag::err_template_instantiate_undefined)
1920      << (TSK != TSK_ImplicitInstantiation)
1921      << S.Context.getTypeDeclType(Instantiation);
1922    S.Diag(Pattern->getLocation(), diag::note_template_decl_here);
1923  }
1924
1925  // In general, Instantiation isn't marked invalid to get more than one
1926  // error for multiple undefined instantiations. But the code that does
1927  // explicit declaration -> explicit definition conversion can't handle
1928  // invalid declarations, so mark as invalid in that case.
1929  if (TSK == TSK_ExplicitInstantiationDeclaration)
1930    Instantiation->setInvalidDecl();
1931  return true;
1932}
1933
1934/// \brief Instantiate the definition of a class from a given pattern.
1935///
1936/// \param PointOfInstantiation The point of instantiation within the
1937/// source code.
1938///
1939/// \param Instantiation is the declaration whose definition is being
1940/// instantiated. This will be either a class template specialization
1941/// or a member class of a class template specialization.
1942///
1943/// \param Pattern is the pattern from which the instantiation
1944/// occurs. This will be either the declaration of a class template or
1945/// the declaration of a member class of a class template.
1946///
1947/// \param TemplateArgs The template arguments to be substituted into
1948/// the pattern.
1949///
1950/// \param TSK the kind of implicit or explicit instantiation to perform.
1951///
1952/// \param Complain whether to complain if the class cannot be instantiated due
1953/// to the lack of a definition.
1954///
1955/// \returns true if an error occurred, false otherwise.
1956bool
1957Sema::InstantiateClass(SourceLocation PointOfInstantiation,
1958                       CXXRecordDecl *Instantiation, CXXRecordDecl *Pattern,
1959                       const MultiLevelTemplateArgumentList &TemplateArgs,
1960                       TemplateSpecializationKind TSK,
1961                       bool Complain) {
1962  CXXRecordDecl *PatternDef
1963    = cast_or_null<CXXRecordDecl>(Pattern->getDefinition());
1964  if (DiagnoseUninstantiableTemplate(*this, PointOfInstantiation, Instantiation,
1965                                Instantiation->getInstantiatedFromMemberClass(),
1966                                     Pattern, PatternDef, TSK, Complain))
1967    return true;
1968  Pattern = PatternDef;
1969
1970  // \brief Record the point of instantiation.
1971  if (MemberSpecializationInfo *MSInfo
1972        = Instantiation->getMemberSpecializationInfo()) {
1973    MSInfo->setTemplateSpecializationKind(TSK);
1974    MSInfo->setPointOfInstantiation(PointOfInstantiation);
1975  } else if (ClassTemplateSpecializationDecl *Spec
1976        = dyn_cast<ClassTemplateSpecializationDecl>(Instantiation)) {
1977    Spec->setTemplateSpecializationKind(TSK);
1978    Spec->setPointOfInstantiation(PointOfInstantiation);
1979  }
1980
1981  InstantiatingTemplate Inst(*this, PointOfInstantiation, Instantiation);
1982  if (Inst)
1983    return true;
1984
1985  // Enter the scope of this instantiation. We don't use
1986  // PushDeclContext because we don't have a scope.
1987  ContextRAII SavedContext(*this, Instantiation);
1988  EnterExpressionEvaluationContext EvalContext(*this,
1989                                               Sema::PotentiallyEvaluated);
1990
1991  // If this is an instantiation of a local class, merge this local
1992  // instantiation scope with the enclosing scope. Otherwise, every
1993  // instantiation of a class has its own local instantiation scope.
1994  bool MergeWithParentScope = !Instantiation->isDefinedOutsideFunctionOrMethod();
1995  LocalInstantiationScope Scope(*this, MergeWithParentScope);
1996
1997  // Pull attributes from the pattern onto the instantiation.
1998  InstantiateAttrs(TemplateArgs, Pattern, Instantiation);
1999
2000  // Start the definition of this instantiation.
2001  Instantiation->startDefinition();
2002
2003  Instantiation->setTagKind(Pattern->getTagKind());
2004
2005  // Do substitution on the base class specifiers.
2006  if (SubstBaseSpecifiers(Instantiation, Pattern, TemplateArgs))
2007    Instantiation->setInvalidDecl();
2008
2009  TemplateDeclInstantiator Instantiator(*this, Instantiation, TemplateArgs);
2010  SmallVector<Decl*, 4> Fields;
2011  SmallVector<std::pair<FieldDecl*, FieldDecl*>, 4>
2012    FieldsWithMemberInitializers;
2013  // Delay instantiation of late parsed attributes.
2014  LateInstantiatedAttrVec LateAttrs;
2015  Instantiator.enableLateAttributeInstantiation(&LateAttrs);
2016
2017  for (RecordDecl::decl_iterator Member = Pattern->decls_begin(),
2018         MemberEnd = Pattern->decls_end();
2019       Member != MemberEnd; ++Member) {
2020    // Don't instantiate members not belonging in this semantic context.
2021    // e.g. for:
2022    // @code
2023    //    template <int i> class A {
2024    //      class B *g;
2025    //    };
2026    // @endcode
2027    // 'class B' has the template as lexical context but semantically it is
2028    // introduced in namespace scope.
2029    if ((*Member)->getDeclContext() != Pattern)
2030      continue;
2031
2032    if ((*Member)->isInvalidDecl()) {
2033      Instantiation->setInvalidDecl();
2034      continue;
2035    }
2036
2037    Decl *NewMember = Instantiator.Visit(*Member);
2038    if (NewMember) {
2039      if (FieldDecl *Field = dyn_cast<FieldDecl>(NewMember)) {
2040        Fields.push_back(Field);
2041        FieldDecl *OldField = cast<FieldDecl>(*Member);
2042        if (OldField->getInClassInitializer())
2043          FieldsWithMemberInitializers.push_back(std::make_pair(OldField,
2044                                                                Field));
2045      } else if (EnumDecl *Enum = dyn_cast<EnumDecl>(NewMember)) {
2046        // C++11 [temp.inst]p1: The implicit instantiation of a class template
2047        // specialization causes the implicit instantiation of the definitions
2048        // of unscoped member enumerations.
2049        // Record a point of instantiation for this implicit instantiation.
2050        if (TSK == TSK_ImplicitInstantiation && !Enum->isScoped() &&
2051            Enum->isCompleteDefinition()) {
2052          MemberSpecializationInfo *MSInfo =Enum->getMemberSpecializationInfo();
2053          assert(MSInfo && "no spec info for member enum specialization");
2054          MSInfo->setTemplateSpecializationKind(TSK_ImplicitInstantiation);
2055          MSInfo->setPointOfInstantiation(PointOfInstantiation);
2056        }
2057      } else if (StaticAssertDecl *SA = dyn_cast<StaticAssertDecl>(NewMember)) {
2058        if (SA->isFailed()) {
2059          // A static_assert failed. Bail out; instantiating this
2060          // class is probably not meaningful.
2061          Instantiation->setInvalidDecl();
2062          break;
2063        }
2064      }
2065
2066      if (NewMember->isInvalidDecl())
2067        Instantiation->setInvalidDecl();
2068    } else {
2069      // FIXME: Eventually, a NULL return will mean that one of the
2070      // instantiations was a semantic disaster, and we'll want to mark the
2071      // declaration invalid.
2072      // For now, we expect to skip some members that we can't yet handle.
2073    }
2074  }
2075
2076  // Finish checking fields.
2077  ActOnFields(0, Instantiation->getLocation(), Instantiation, Fields,
2078              SourceLocation(), SourceLocation(), 0);
2079  CheckCompletedCXXClass(Instantiation);
2080
2081  // Attach any in-class member initializers now the class is complete.
2082  // FIXME: We are supposed to defer instantiating these until they are needed.
2083  if (!FieldsWithMemberInitializers.empty()) {
2084    // C++11 [expr.prim.general]p4:
2085    //   Otherwise, if a member-declarator declares a non-static data member
2086    //  (9.2) of a class X, the expression this is a prvalue of type "pointer
2087    //  to X" within the optional brace-or-equal-initializer. It shall not
2088    //  appear elsewhere in the member-declarator.
2089    CXXThisScopeRAII ThisScope(*this, Instantiation, (unsigned)0);
2090
2091    for (unsigned I = 0, N = FieldsWithMemberInitializers.size(); I != N; ++I) {
2092      FieldDecl *OldField = FieldsWithMemberInitializers[I].first;
2093      FieldDecl *NewField = FieldsWithMemberInitializers[I].second;
2094      Expr *OldInit = OldField->getInClassInitializer();
2095
2096      ExprResult NewInit = SubstInitializer(OldInit, TemplateArgs,
2097                                            /*CXXDirectInit=*/false);
2098      if (NewInit.isInvalid())
2099        NewField->setInvalidDecl();
2100      else {
2101        Expr *Init = NewInit.take();
2102        assert(Init && "no-argument initializer in class");
2103        assert(!isa<ParenListExpr>(Init) && "call-style init in class");
2104        ActOnCXXInClassMemberInitializer(NewField, Init->getLocStart(), Init);
2105      }
2106    }
2107  }
2108  // Instantiate late parsed attributes, and attach them to their decls.
2109  // See Sema::InstantiateAttrs
2110  for (LateInstantiatedAttrVec::iterator I = LateAttrs.begin(),
2111       E = LateAttrs.end(); I != E; ++I) {
2112    assert(CurrentInstantiationScope == Instantiator.getStartingScope());
2113    CurrentInstantiationScope = I->Scope;
2114
2115    // Allow 'this' within late-parsed attributes.
2116    NamedDecl *ND = dyn_cast<NamedDecl>(I->NewDecl);
2117    CXXRecordDecl *ThisContext =
2118        dyn_cast_or_null<CXXRecordDecl>(ND->getDeclContext());
2119    CXXThisScopeRAII ThisScope(*this, ThisContext, /*TypeQuals*/0,
2120                               ND && ND->isCXXInstanceMember());
2121
2122    Attr *NewAttr =
2123      instantiateTemplateAttribute(I->TmplAttr, Context, *this, TemplateArgs);
2124    I->NewDecl->addAttr(NewAttr);
2125    LocalInstantiationScope::deleteScopes(I->Scope,
2126                                          Instantiator.getStartingScope());
2127  }
2128  Instantiator.disableLateAttributeInstantiation();
2129  LateAttrs.clear();
2130
2131  ActOnFinishDelayedMemberInitializers(Instantiation);
2132
2133  if (TSK == TSK_ImplicitInstantiation) {
2134    Instantiation->setLocation(Pattern->getLocation());
2135    Instantiation->setLocStart(Pattern->getInnerLocStart());
2136    Instantiation->setRBraceLoc(Pattern->getRBraceLoc());
2137  }
2138
2139  if (!Instantiation->isInvalidDecl()) {
2140    // Perform any dependent diagnostics from the pattern.
2141    PerformDependentDiagnostics(Pattern, TemplateArgs);
2142
2143    // Instantiate any out-of-line class template partial
2144    // specializations now.
2145    for (TemplateDeclInstantiator::delayed_partial_spec_iterator
2146              P = Instantiator.delayed_partial_spec_begin(),
2147           PEnd = Instantiator.delayed_partial_spec_end();
2148         P != PEnd; ++P) {
2149      if (!Instantiator.InstantiateClassTemplatePartialSpecialization(
2150              P->first, P->second)) {
2151        Instantiation->setInvalidDecl();
2152        break;
2153      }
2154    }
2155
2156    // Instantiate any out-of-line variable template partial
2157    // specializations now.
2158    for (TemplateDeclInstantiator::delayed_var_partial_spec_iterator
2159              P = Instantiator.delayed_var_partial_spec_begin(),
2160           PEnd = Instantiator.delayed_var_partial_spec_end();
2161         P != PEnd; ++P) {
2162      if (!Instantiator.InstantiateVarTemplatePartialSpecialization(
2163              P->first, P->second)) {
2164        Instantiation->setInvalidDecl();
2165        break;
2166      }
2167    }
2168  }
2169
2170  // Exit the scope of this instantiation.
2171  SavedContext.pop();
2172
2173  if (!Instantiation->isInvalidDecl()) {
2174    Consumer.HandleTagDeclDefinition(Instantiation);
2175
2176    // Always emit the vtable for an explicit instantiation definition
2177    // of a polymorphic class template specialization.
2178    if (TSK == TSK_ExplicitInstantiationDefinition)
2179      MarkVTableUsed(PointOfInstantiation, Instantiation, true);
2180  }
2181
2182  return Instantiation->isInvalidDecl();
2183}
2184
2185/// \brief Instantiate the definition of an enum from a given pattern.
2186///
2187/// \param PointOfInstantiation The point of instantiation within the
2188///        source code.
2189/// \param Instantiation is the declaration whose definition is being
2190///        instantiated. This will be a member enumeration of a class
2191///        temploid specialization, or a local enumeration within a
2192///        function temploid specialization.
2193/// \param Pattern The templated declaration from which the instantiation
2194///        occurs.
2195/// \param TemplateArgs The template arguments to be substituted into
2196///        the pattern.
2197/// \param TSK The kind of implicit or explicit instantiation to perform.
2198///
2199/// \return \c true if an error occurred, \c false otherwise.
2200bool Sema::InstantiateEnum(SourceLocation PointOfInstantiation,
2201                           EnumDecl *Instantiation, EnumDecl *Pattern,
2202                           const MultiLevelTemplateArgumentList &TemplateArgs,
2203                           TemplateSpecializationKind TSK) {
2204  EnumDecl *PatternDef = Pattern->getDefinition();
2205  if (DiagnoseUninstantiableTemplate(*this, PointOfInstantiation, Instantiation,
2206                                 Instantiation->getInstantiatedFromMemberEnum(),
2207                                     Pattern, PatternDef, TSK,/*Complain*/true))
2208    return true;
2209  Pattern = PatternDef;
2210
2211  // Record the point of instantiation.
2212  if (MemberSpecializationInfo *MSInfo
2213        = Instantiation->getMemberSpecializationInfo()) {
2214    MSInfo->setTemplateSpecializationKind(TSK);
2215    MSInfo->setPointOfInstantiation(PointOfInstantiation);
2216  }
2217
2218  InstantiatingTemplate Inst(*this, PointOfInstantiation, Instantiation);
2219  if (Inst)
2220    return true;
2221
2222  // Enter the scope of this instantiation. We don't use
2223  // PushDeclContext because we don't have a scope.
2224  ContextRAII SavedContext(*this, Instantiation);
2225  EnterExpressionEvaluationContext EvalContext(*this,
2226                                               Sema::PotentiallyEvaluated);
2227
2228  LocalInstantiationScope Scope(*this, /*MergeWithParentScope*/true);
2229
2230  // Pull attributes from the pattern onto the instantiation.
2231  InstantiateAttrs(TemplateArgs, Pattern, Instantiation);
2232
2233  TemplateDeclInstantiator Instantiator(*this, Instantiation, TemplateArgs);
2234  Instantiator.InstantiateEnumDefinition(Instantiation, Pattern);
2235
2236  // Exit the scope of this instantiation.
2237  SavedContext.pop();
2238
2239  return Instantiation->isInvalidDecl();
2240}
2241
2242namespace {
2243  /// \brief A partial specialization whose template arguments have matched
2244  /// a given template-id.
2245  struct PartialSpecMatchResult {
2246    ClassTemplatePartialSpecializationDecl *Partial;
2247    TemplateArgumentList *Args;
2248  };
2249}
2250
2251bool Sema::InstantiateClassTemplateSpecialization(
2252    SourceLocation PointOfInstantiation,
2253    ClassTemplateSpecializationDecl *ClassTemplateSpec,
2254    TemplateSpecializationKind TSK, bool Complain) {
2255  // Perform the actual instantiation on the canonical declaration.
2256  ClassTemplateSpec = cast<ClassTemplateSpecializationDecl>(
2257                                         ClassTemplateSpec->getCanonicalDecl());
2258
2259  // Check whether we have already instantiated or specialized this class
2260  // template specialization.
2261  if (ClassTemplateSpec->getSpecializationKind() != TSK_Undeclared) {
2262    if (ClassTemplateSpec->getSpecializationKind() ==
2263          TSK_ExplicitInstantiationDeclaration &&
2264        TSK == TSK_ExplicitInstantiationDefinition) {
2265      // An explicit instantiation definition follows an explicit instantiation
2266      // declaration (C++0x [temp.explicit]p10); go ahead and perform the
2267      // explicit instantiation.
2268      ClassTemplateSpec->setSpecializationKind(TSK);
2269
2270      // If this is an explicit instantiation definition, mark the
2271      // vtable as used.
2272      if (TSK == TSK_ExplicitInstantiationDefinition &&
2273          !ClassTemplateSpec->isInvalidDecl())
2274        MarkVTableUsed(PointOfInstantiation, ClassTemplateSpec, true);
2275
2276      return false;
2277    }
2278
2279    // We can only instantiate something that hasn't already been
2280    // instantiated or specialized. Fail without any diagnostics: our
2281    // caller will provide an error message.
2282    return true;
2283  }
2284
2285  if (ClassTemplateSpec->isInvalidDecl())
2286    return true;
2287
2288  ClassTemplateDecl *Template = ClassTemplateSpec->getSpecializedTemplate();
2289  CXXRecordDecl *Pattern = 0;
2290
2291  // C++ [temp.class.spec.match]p1:
2292  //   When a class template is used in a context that requires an
2293  //   instantiation of the class, it is necessary to determine
2294  //   whether the instantiation is to be generated using the primary
2295  //   template or one of the partial specializations. This is done by
2296  //   matching the template arguments of the class template
2297  //   specialization with the template argument lists of the partial
2298  //   specializations.
2299  typedef PartialSpecMatchResult MatchResult;
2300  SmallVector<MatchResult, 4> Matched;
2301  SmallVector<ClassTemplatePartialSpecializationDecl *, 4> PartialSpecs;
2302  Template->getPartialSpecializations(PartialSpecs);
2303  TemplateSpecCandidateSet FailedCandidates(PointOfInstantiation);
2304  for (unsigned I = 0, N = PartialSpecs.size(); I != N; ++I) {
2305    ClassTemplatePartialSpecializationDecl *Partial = PartialSpecs[I];
2306    TemplateDeductionInfo Info(FailedCandidates.getLocation());
2307    if (TemplateDeductionResult Result
2308          = DeduceTemplateArguments(Partial,
2309                                    ClassTemplateSpec->getTemplateArgs(),
2310                                    Info)) {
2311      // Store the failed-deduction information for use in diagnostics, later.
2312      // TODO: Actually use the failed-deduction info?
2313      FailedCandidates.addCandidate()
2314          .set(Partial, MakeDeductionFailureInfo(Context, Result, Info));
2315      (void)Result;
2316    } else {
2317      Matched.push_back(PartialSpecMatchResult());
2318      Matched.back().Partial = Partial;
2319      Matched.back().Args = Info.take();
2320    }
2321  }
2322
2323  // If we're dealing with a member template where the template parameters
2324  // have been instantiated, this provides the original template parameters
2325  // from which the member template's parameters were instantiated.
2326  SmallVector<const NamedDecl *, 4> InstantiatedTemplateParameters;
2327
2328  if (Matched.size() >= 1) {
2329    SmallVectorImpl<MatchResult>::iterator Best = Matched.begin();
2330    if (Matched.size() == 1) {
2331      //   -- If exactly one matching specialization is found, the
2332      //      instantiation is generated from that specialization.
2333      // We don't need to do anything for this.
2334    } else {
2335      //   -- If more than one matching specialization is found, the
2336      //      partial order rules (14.5.4.2) are used to determine
2337      //      whether one of the specializations is more specialized
2338      //      than the others. If none of the specializations is more
2339      //      specialized than all of the other matching
2340      //      specializations, then the use of the class template is
2341      //      ambiguous and the program is ill-formed.
2342      for (SmallVectorImpl<MatchResult>::iterator P = Best + 1,
2343                                               PEnd = Matched.end();
2344           P != PEnd; ++P) {
2345        if (getMoreSpecializedPartialSpecialization(P->Partial, Best->Partial,
2346                                                    PointOfInstantiation)
2347              == P->Partial)
2348          Best = P;
2349      }
2350
2351      // Determine if the best partial specialization is more specialized than
2352      // the others.
2353      bool Ambiguous = false;
2354      for (SmallVectorImpl<MatchResult>::iterator P = Matched.begin(),
2355                                               PEnd = Matched.end();
2356           P != PEnd; ++P) {
2357        if (P != Best &&
2358            getMoreSpecializedPartialSpecialization(P->Partial, Best->Partial,
2359                                                    PointOfInstantiation)
2360              != Best->Partial) {
2361          Ambiguous = true;
2362          break;
2363        }
2364      }
2365
2366      if (Ambiguous) {
2367        // Partial ordering did not produce a clear winner. Complain.
2368        ClassTemplateSpec->setInvalidDecl();
2369        Diag(PointOfInstantiation, diag::err_partial_spec_ordering_ambiguous)
2370          << ClassTemplateSpec;
2371
2372        // Print the matching partial specializations.
2373        for (SmallVectorImpl<MatchResult>::iterator P = Matched.begin(),
2374                                                 PEnd = Matched.end();
2375             P != PEnd; ++P)
2376          Diag(P->Partial->getLocation(), diag::note_partial_spec_match)
2377            << getTemplateArgumentBindingsText(
2378                                            P->Partial->getTemplateParameters(),
2379                                               *P->Args);
2380
2381        return true;
2382      }
2383    }
2384
2385    // Instantiate using the best class template partial specialization.
2386    ClassTemplatePartialSpecializationDecl *OrigPartialSpec = Best->Partial;
2387    while (OrigPartialSpec->getInstantiatedFromMember()) {
2388      // If we've found an explicit specialization of this class template,
2389      // stop here and use that as the pattern.
2390      if (OrigPartialSpec->isMemberSpecialization())
2391        break;
2392
2393      OrigPartialSpec = OrigPartialSpec->getInstantiatedFromMember();
2394    }
2395
2396    Pattern = OrigPartialSpec;
2397    ClassTemplateSpec->setInstantiationOf(Best->Partial, Best->Args);
2398  } else {
2399    //   -- If no matches are found, the instantiation is generated
2400    //      from the primary template.
2401    ClassTemplateDecl *OrigTemplate = Template;
2402    while (OrigTemplate->getInstantiatedFromMemberTemplate()) {
2403      // If we've found an explicit specialization of this class template,
2404      // stop here and use that as the pattern.
2405      if (OrigTemplate->isMemberSpecialization())
2406        break;
2407
2408      OrigTemplate = OrigTemplate->getInstantiatedFromMemberTemplate();
2409    }
2410
2411    Pattern = OrigTemplate->getTemplatedDecl();
2412  }
2413
2414  bool Result = InstantiateClass(PointOfInstantiation, ClassTemplateSpec,
2415                                 Pattern,
2416                                getTemplateInstantiationArgs(ClassTemplateSpec),
2417                                 TSK,
2418                                 Complain);
2419
2420  return Result;
2421}
2422
2423/// \brief Instantiates the definitions of all of the member
2424/// of the given class, which is an instantiation of a class template
2425/// or a member class of a template.
2426void
2427Sema::InstantiateClassMembers(SourceLocation PointOfInstantiation,
2428                              CXXRecordDecl *Instantiation,
2429                        const MultiLevelTemplateArgumentList &TemplateArgs,
2430                              TemplateSpecializationKind TSK) {
2431  for (DeclContext::decl_iterator D = Instantiation->decls_begin(),
2432                               DEnd = Instantiation->decls_end();
2433       D != DEnd; ++D) {
2434    bool SuppressNew = false;
2435    if (FunctionDecl *Function = dyn_cast<FunctionDecl>(*D)) {
2436      if (FunctionDecl *Pattern
2437            = Function->getInstantiatedFromMemberFunction()) {
2438        MemberSpecializationInfo *MSInfo
2439          = Function->getMemberSpecializationInfo();
2440        assert(MSInfo && "No member specialization information?");
2441        if (MSInfo->getTemplateSpecializationKind()
2442                                                 == TSK_ExplicitSpecialization)
2443          continue;
2444
2445        if (CheckSpecializationInstantiationRedecl(PointOfInstantiation, TSK,
2446                                                   Function,
2447                                        MSInfo->getTemplateSpecializationKind(),
2448                                              MSInfo->getPointOfInstantiation(),
2449                                                   SuppressNew) ||
2450            SuppressNew)
2451          continue;
2452
2453        if (Function->isDefined())
2454          continue;
2455
2456        if (TSK == TSK_ExplicitInstantiationDefinition) {
2457          // C++0x [temp.explicit]p8:
2458          //   An explicit instantiation definition that names a class template
2459          //   specialization explicitly instantiates the class template
2460          //   specialization and is only an explicit instantiation definition
2461          //   of members whose definition is visible at the point of
2462          //   instantiation.
2463          if (!Pattern->isDefined())
2464            continue;
2465
2466          Function->setTemplateSpecializationKind(TSK, PointOfInstantiation);
2467
2468          InstantiateFunctionDefinition(PointOfInstantiation, Function);
2469        } else {
2470          Function->setTemplateSpecializationKind(TSK, PointOfInstantiation);
2471        }
2472      }
2473    } else if (VarDecl *Var = dyn_cast<VarDecl>(*D)) {
2474      if (Var->isStaticDataMember()) {
2475        MemberSpecializationInfo *MSInfo = Var->getMemberSpecializationInfo();
2476        assert(MSInfo && "No member specialization information?");
2477        if (MSInfo->getTemplateSpecializationKind()
2478                                                 == TSK_ExplicitSpecialization)
2479          continue;
2480
2481        if (CheckSpecializationInstantiationRedecl(PointOfInstantiation, TSK,
2482                                                   Var,
2483                                        MSInfo->getTemplateSpecializationKind(),
2484                                              MSInfo->getPointOfInstantiation(),
2485                                                   SuppressNew) ||
2486            SuppressNew)
2487          continue;
2488
2489        if (TSK == TSK_ExplicitInstantiationDefinition) {
2490          // C++0x [temp.explicit]p8:
2491          //   An explicit instantiation definition that names a class template
2492          //   specialization explicitly instantiates the class template
2493          //   specialization and is only an explicit instantiation definition
2494          //   of members whose definition is visible at the point of
2495          //   instantiation.
2496          if (!Var->getInstantiatedFromStaticDataMember()
2497                                                     ->getOutOfLineDefinition())
2498            continue;
2499
2500          Var->setTemplateSpecializationKind(TSK, PointOfInstantiation);
2501          InstantiateStaticDataMemberDefinition(PointOfInstantiation, Var);
2502        } else {
2503          Var->setTemplateSpecializationKind(TSK, PointOfInstantiation);
2504        }
2505      }
2506    } else if (CXXRecordDecl *Record = dyn_cast<CXXRecordDecl>(*D)) {
2507      // Always skip the injected-class-name, along with any
2508      // redeclarations of nested classes, since both would cause us
2509      // to try to instantiate the members of a class twice.
2510      if (Record->isInjectedClassName() || Record->getPreviousDecl())
2511        continue;
2512
2513      MemberSpecializationInfo *MSInfo = Record->getMemberSpecializationInfo();
2514      assert(MSInfo && "No member specialization information?");
2515
2516      if (MSInfo->getTemplateSpecializationKind()
2517                                                == TSK_ExplicitSpecialization)
2518        continue;
2519
2520      if (CheckSpecializationInstantiationRedecl(PointOfInstantiation, TSK,
2521                                                 Record,
2522                                        MSInfo->getTemplateSpecializationKind(),
2523                                              MSInfo->getPointOfInstantiation(),
2524                                                 SuppressNew) ||
2525          SuppressNew)
2526        continue;
2527
2528      CXXRecordDecl *Pattern = Record->getInstantiatedFromMemberClass();
2529      assert(Pattern && "Missing instantiated-from-template information");
2530
2531      if (!Record->getDefinition()) {
2532        if (!Pattern->getDefinition()) {
2533          // C++0x [temp.explicit]p8:
2534          //   An explicit instantiation definition that names a class template
2535          //   specialization explicitly instantiates the class template
2536          //   specialization and is only an explicit instantiation definition
2537          //   of members whose definition is visible at the point of
2538          //   instantiation.
2539          if (TSK == TSK_ExplicitInstantiationDeclaration) {
2540            MSInfo->setTemplateSpecializationKind(TSK);
2541            MSInfo->setPointOfInstantiation(PointOfInstantiation);
2542          }
2543
2544          continue;
2545        }
2546
2547        InstantiateClass(PointOfInstantiation, Record, Pattern,
2548                         TemplateArgs,
2549                         TSK);
2550      } else {
2551        if (TSK == TSK_ExplicitInstantiationDefinition &&
2552            Record->getTemplateSpecializationKind() ==
2553                TSK_ExplicitInstantiationDeclaration) {
2554          Record->setTemplateSpecializationKind(TSK);
2555          MarkVTableUsed(PointOfInstantiation, Record, true);
2556        }
2557      }
2558
2559      Pattern = cast_or_null<CXXRecordDecl>(Record->getDefinition());
2560      if (Pattern)
2561        InstantiateClassMembers(PointOfInstantiation, Pattern, TemplateArgs,
2562                                TSK);
2563    } else if (EnumDecl *Enum = dyn_cast<EnumDecl>(*D)) {
2564      MemberSpecializationInfo *MSInfo = Enum->getMemberSpecializationInfo();
2565      assert(MSInfo && "No member specialization information?");
2566
2567      if (MSInfo->getTemplateSpecializationKind()
2568            == TSK_ExplicitSpecialization)
2569        continue;
2570
2571      if (CheckSpecializationInstantiationRedecl(
2572            PointOfInstantiation, TSK, Enum,
2573            MSInfo->getTemplateSpecializationKind(),
2574            MSInfo->getPointOfInstantiation(), SuppressNew) ||
2575          SuppressNew)
2576        continue;
2577
2578      if (Enum->getDefinition())
2579        continue;
2580
2581      EnumDecl *Pattern = Enum->getInstantiatedFromMemberEnum();
2582      assert(Pattern && "Missing instantiated-from-template information");
2583
2584      if (TSK == TSK_ExplicitInstantiationDefinition) {
2585        if (!Pattern->getDefinition())
2586          continue;
2587
2588        InstantiateEnum(PointOfInstantiation, Enum, Pattern, TemplateArgs, TSK);
2589      } else {
2590        MSInfo->setTemplateSpecializationKind(TSK);
2591        MSInfo->setPointOfInstantiation(PointOfInstantiation);
2592      }
2593    }
2594  }
2595}
2596
2597/// \brief Instantiate the definitions of all of the members of the
2598/// given class template specialization, which was named as part of an
2599/// explicit instantiation.
2600void
2601Sema::InstantiateClassTemplateSpecializationMembers(
2602                                           SourceLocation PointOfInstantiation,
2603                            ClassTemplateSpecializationDecl *ClassTemplateSpec,
2604                                               TemplateSpecializationKind TSK) {
2605  // C++0x [temp.explicit]p7:
2606  //   An explicit instantiation that names a class template
2607  //   specialization is an explicit instantion of the same kind
2608  //   (declaration or definition) of each of its members (not
2609  //   including members inherited from base classes) that has not
2610  //   been previously explicitly specialized in the translation unit
2611  //   containing the explicit instantiation, except as described
2612  //   below.
2613  InstantiateClassMembers(PointOfInstantiation, ClassTemplateSpec,
2614                          getTemplateInstantiationArgs(ClassTemplateSpec),
2615                          TSK);
2616}
2617
2618StmtResult
2619Sema::SubstStmt(Stmt *S, const MultiLevelTemplateArgumentList &TemplateArgs) {
2620  if (!S)
2621    return Owned(S);
2622
2623  TemplateInstantiator Instantiator(*this, TemplateArgs,
2624                                    SourceLocation(),
2625                                    DeclarationName());
2626  return Instantiator.TransformStmt(S);
2627}
2628
2629ExprResult
2630Sema::SubstExpr(Expr *E, const MultiLevelTemplateArgumentList &TemplateArgs) {
2631  if (!E)
2632    return Owned(E);
2633
2634  TemplateInstantiator Instantiator(*this, TemplateArgs,
2635                                    SourceLocation(),
2636                                    DeclarationName());
2637  return Instantiator.TransformExpr(E);
2638}
2639
2640ExprResult Sema::SubstInitializer(Expr *Init,
2641                          const MultiLevelTemplateArgumentList &TemplateArgs,
2642                          bool CXXDirectInit) {
2643  TemplateInstantiator Instantiator(*this, TemplateArgs,
2644                                    SourceLocation(),
2645                                    DeclarationName());
2646  return Instantiator.TransformInitializer(Init, CXXDirectInit);
2647}
2648
2649bool Sema::SubstExprs(Expr **Exprs, unsigned NumExprs, bool IsCall,
2650                      const MultiLevelTemplateArgumentList &TemplateArgs,
2651                      SmallVectorImpl<Expr *> &Outputs) {
2652  if (NumExprs == 0)
2653    return false;
2654
2655  TemplateInstantiator Instantiator(*this, TemplateArgs,
2656                                    SourceLocation(),
2657                                    DeclarationName());
2658  return Instantiator.TransformExprs(Exprs, NumExprs, IsCall, Outputs);
2659}
2660
2661NestedNameSpecifierLoc
2662Sema::SubstNestedNameSpecifierLoc(NestedNameSpecifierLoc NNS,
2663                        const MultiLevelTemplateArgumentList &TemplateArgs) {
2664  if (!NNS)
2665    return NestedNameSpecifierLoc();
2666
2667  TemplateInstantiator Instantiator(*this, TemplateArgs, NNS.getBeginLoc(),
2668                                    DeclarationName());
2669  return Instantiator.TransformNestedNameSpecifierLoc(NNS);
2670}
2671
2672/// \brief Do template substitution on declaration name info.
2673DeclarationNameInfo
2674Sema::SubstDeclarationNameInfo(const DeclarationNameInfo &NameInfo,
2675                         const MultiLevelTemplateArgumentList &TemplateArgs) {
2676  TemplateInstantiator Instantiator(*this, TemplateArgs, NameInfo.getLoc(),
2677                                    NameInfo.getName());
2678  return Instantiator.TransformDeclarationNameInfo(NameInfo);
2679}
2680
2681TemplateName
2682Sema::SubstTemplateName(NestedNameSpecifierLoc QualifierLoc,
2683                        TemplateName Name, SourceLocation Loc,
2684                        const MultiLevelTemplateArgumentList &TemplateArgs) {
2685  TemplateInstantiator Instantiator(*this, TemplateArgs, Loc,
2686                                    DeclarationName());
2687  CXXScopeSpec SS;
2688  SS.Adopt(QualifierLoc);
2689  return Instantiator.TransformTemplateName(SS, Name, Loc);
2690}
2691
2692bool Sema::Subst(const TemplateArgumentLoc *Args, unsigned NumArgs,
2693                 TemplateArgumentListInfo &Result,
2694                 const MultiLevelTemplateArgumentList &TemplateArgs) {
2695  TemplateInstantiator Instantiator(*this, TemplateArgs, SourceLocation(),
2696                                    DeclarationName());
2697
2698  return Instantiator.TransformTemplateArguments(Args, NumArgs, Result);
2699}
2700
2701
2702static const Decl* getCanonicalParmVarDecl(const Decl *D) {
2703  // When storing ParmVarDecls in the local instantiation scope, we always
2704  // want to use the ParmVarDecl from the canonical function declaration,
2705  // since the map is then valid for any redeclaration or definition of that
2706  // function.
2707  if (const ParmVarDecl *PV = dyn_cast<ParmVarDecl>(D)) {
2708    if (const FunctionDecl *FD = dyn_cast<FunctionDecl>(PV->getDeclContext())) {
2709      unsigned i = PV->getFunctionScopeIndex();
2710      return FD->getCanonicalDecl()->getParamDecl(i);
2711    }
2712  }
2713  return D;
2714}
2715
2716
2717llvm::PointerUnion<Decl *, LocalInstantiationScope::DeclArgumentPack *> *
2718LocalInstantiationScope::findInstantiationOf(const Decl *D) {
2719  D = getCanonicalParmVarDecl(D);
2720  for (LocalInstantiationScope *Current = this; Current;
2721       Current = Current->Outer) {
2722
2723    // Check if we found something within this scope.
2724    const Decl *CheckD = D;
2725    do {
2726      LocalDeclsMap::iterator Found = Current->LocalDecls.find(CheckD);
2727      if (Found != Current->LocalDecls.end())
2728        return &Found->second;
2729
2730      // If this is a tag declaration, it's possible that we need to look for
2731      // a previous declaration.
2732      if (const TagDecl *Tag = dyn_cast<TagDecl>(CheckD))
2733        CheckD = Tag->getPreviousDecl();
2734      else
2735        CheckD = 0;
2736    } while (CheckD);
2737
2738    // If we aren't combined with our outer scope, we're done.
2739    if (!Current->CombineWithOuterScope)
2740      break;
2741  }
2742
2743  // If we're performing a partial substitution during template argument
2744  // deduction, we may not have values for template parameters yet.
2745  if (isa<NonTypeTemplateParmDecl>(D) || isa<TemplateTypeParmDecl>(D) ||
2746      isa<TemplateTemplateParmDecl>(D))
2747    return 0;
2748
2749  // If we didn't find the decl, then we either have a sema bug, or we have a
2750  // forward reference to a label declaration.  Return null to indicate that
2751  // we have an uninstantiated label.
2752  assert(isa<LabelDecl>(D) && "declaration not instantiated in this scope");
2753  return 0;
2754}
2755
2756void LocalInstantiationScope::InstantiatedLocal(const Decl *D, Decl *Inst) {
2757  D = getCanonicalParmVarDecl(D);
2758  llvm::PointerUnion<Decl *, DeclArgumentPack *> &Stored = LocalDecls[D];
2759  if (Stored.isNull())
2760    Stored = Inst;
2761  else if (DeclArgumentPack *Pack = Stored.dyn_cast<DeclArgumentPack *>())
2762    Pack->push_back(Inst);
2763  else
2764    assert(Stored.get<Decl *>() == Inst && "Already instantiated this local");
2765}
2766
2767void LocalInstantiationScope::InstantiatedLocalPackArg(const Decl *D,
2768                                                       Decl *Inst) {
2769  D = getCanonicalParmVarDecl(D);
2770  DeclArgumentPack *Pack = LocalDecls[D].get<DeclArgumentPack *>();
2771  Pack->push_back(Inst);
2772}
2773
2774void LocalInstantiationScope::MakeInstantiatedLocalArgPack(const Decl *D) {
2775  D = getCanonicalParmVarDecl(D);
2776  llvm::PointerUnion<Decl *, DeclArgumentPack *> &Stored = LocalDecls[D];
2777  assert(Stored.isNull() && "Already instantiated this local");
2778  DeclArgumentPack *Pack = new DeclArgumentPack;
2779  Stored = Pack;
2780  ArgumentPacks.push_back(Pack);
2781}
2782
2783void LocalInstantiationScope::SetPartiallySubstitutedPack(NamedDecl *Pack,
2784                                          const TemplateArgument *ExplicitArgs,
2785                                                    unsigned NumExplicitArgs) {
2786  assert((!PartiallySubstitutedPack || PartiallySubstitutedPack == Pack) &&
2787         "Already have a partially-substituted pack");
2788  assert((!PartiallySubstitutedPack
2789          || NumArgsInPartiallySubstitutedPack == NumExplicitArgs) &&
2790         "Wrong number of arguments in partially-substituted pack");
2791  PartiallySubstitutedPack = Pack;
2792  ArgsInPartiallySubstitutedPack = ExplicitArgs;
2793  NumArgsInPartiallySubstitutedPack = NumExplicitArgs;
2794}
2795
2796NamedDecl *LocalInstantiationScope::getPartiallySubstitutedPack(
2797                                         const TemplateArgument **ExplicitArgs,
2798                                              unsigned *NumExplicitArgs) const {
2799  if (ExplicitArgs)
2800    *ExplicitArgs = 0;
2801  if (NumExplicitArgs)
2802    *NumExplicitArgs = 0;
2803
2804  for (const LocalInstantiationScope *Current = this; Current;
2805       Current = Current->Outer) {
2806    if (Current->PartiallySubstitutedPack) {
2807      if (ExplicitArgs)
2808        *ExplicitArgs = Current->ArgsInPartiallySubstitutedPack;
2809      if (NumExplicitArgs)
2810        *NumExplicitArgs = Current->NumArgsInPartiallySubstitutedPack;
2811
2812      return Current->PartiallySubstitutedPack;
2813    }
2814
2815    if (!Current->CombineWithOuterScope)
2816      break;
2817  }
2818
2819  return 0;
2820}
2821