SemaTemplateInstantiateDecl.cpp revision dc2e3d7e5ca0fd57121cd7680825565de704ef31 
1//===--- SemaTemplateInstantiateDecl.cpp - C++ Template Decl Instantiation ===/
2//
3//                     The LLVM Compiler Infrastructure
4//
5// This file is distributed under the University of Illinois Open Source
6// License. See LICENSE.TXT for details.
7//===----------------------------------------------------------------------===/
8//
9//  This file implements C++ template instantiation for declarations.
10//
11//===----------------------------------------------------------------------===/
12#include "Sema.h"
13#include "clang/AST/ASTConsumer.h"
14#include "clang/AST/ASTContext.h"
15#include "clang/AST/DeclTemplate.h"
16#include "clang/AST/DeclVisitor.h"
17#include "clang/AST/Expr.h"
18#include "clang/Basic/PrettyStackTrace.h"
19#include "clang/Lex/Preprocessor.h"
20#include "llvm/Support/Compiler.h"
21
22using namespace clang;
23
24namespace {
25  class VISIBILITY_HIDDEN TemplateDeclInstantiator
26    : public DeclVisitor<TemplateDeclInstantiator, Decl *> {
27    Sema &SemaRef;
28    DeclContext *Owner;
29    const MultiLevelTemplateArgumentList &TemplateArgs;
30
31  public:
32    typedef Sema::OwningExprResult OwningExprResult;
33
34    TemplateDeclInstantiator(Sema &SemaRef, DeclContext *Owner,
35                             const MultiLevelTemplateArgumentList &TemplateArgs)
36      : SemaRef(SemaRef), Owner(Owner), TemplateArgs(TemplateArgs) { }
37
38    // FIXME: Once we get closer to completion, replace these manually-written
39    // declarations with automatically-generated ones from
40    // clang/AST/DeclNodes.def.
41    Decl *VisitTranslationUnitDecl(TranslationUnitDecl *D);
42    Decl *VisitNamespaceDecl(NamespaceDecl *D);
43    Decl *VisitTypedefDecl(TypedefDecl *D);
44    Decl *VisitVarDecl(VarDecl *D);
45    Decl *VisitFieldDecl(FieldDecl *D);
46    Decl *VisitStaticAssertDecl(StaticAssertDecl *D);
47    Decl *VisitEnumDecl(EnumDecl *D);
48    Decl *VisitEnumConstantDecl(EnumConstantDecl *D);
49    Decl *VisitFriendDecl(FriendDecl *D);
50    Decl *VisitFunctionDecl(FunctionDecl *D,
51                            TemplateParameterList *TemplateParams = 0);
52    Decl *VisitCXXRecordDecl(CXXRecordDecl *D);
53    Decl *VisitCXXMethodDecl(CXXMethodDecl *D,
54                             TemplateParameterList *TemplateParams = 0);
55    Decl *VisitCXXConstructorDecl(CXXConstructorDecl *D);
56    Decl *VisitCXXDestructorDecl(CXXDestructorDecl *D);
57    Decl *VisitCXXConversionDecl(CXXConversionDecl *D);
58    ParmVarDecl *VisitParmVarDecl(ParmVarDecl *D);
59    Decl *VisitOriginalParmVarDecl(OriginalParmVarDecl *D);
60    Decl *VisitClassTemplateDecl(ClassTemplateDecl *D);
61    Decl *VisitClassTemplatePartialSpecializationDecl(
62                                    ClassTemplatePartialSpecializationDecl *D);
63    Decl *VisitFunctionTemplateDecl(FunctionTemplateDecl *D);
64    Decl *VisitTemplateTypeParmDecl(TemplateTypeParmDecl *D);
65    Decl *VisitUnresolvedUsingDecl(UnresolvedUsingDecl *D);
66
67    // Base case. FIXME: Remove once we can instantiate everything.
68    Decl *VisitDecl(Decl *) {
69      assert(false && "Template instantiation of unknown declaration kind!");
70      return 0;
71    }
72
73    const LangOptions &getLangOptions() {
74      return SemaRef.getLangOptions();
75    }
76
77    // Helper functions for instantiating methods.
78    QualType SubstFunctionType(FunctionDecl *D,
79                             llvm::SmallVectorImpl<ParmVarDecl *> &Params);
80    bool InitFunctionInstantiation(FunctionDecl *New, FunctionDecl *Tmpl);
81    bool InitMethodInstantiation(CXXMethodDecl *New, CXXMethodDecl *Tmpl);
82
83    TemplateParameterList *
84      SubstTemplateParams(TemplateParameterList *List);
85  };
86}
87
88Decl *
89TemplateDeclInstantiator::VisitTranslationUnitDecl(TranslationUnitDecl *D) {
90  assert(false && "Translation units cannot be instantiated");
91  return D;
92}
93
94Decl *
95TemplateDeclInstantiator::VisitNamespaceDecl(NamespaceDecl *D) {
96  assert(false && "Namespaces cannot be instantiated");
97  return D;
98}
99
100Decl *TemplateDeclInstantiator::VisitTypedefDecl(TypedefDecl *D) {
101  bool Invalid = false;
102  QualType T = D->getUnderlyingType();
103  if (T->isDependentType()) {
104    T = SemaRef.SubstType(T, TemplateArgs,
105                          D->getLocation(), D->getDeclName());
106    if (T.isNull()) {
107      Invalid = true;
108      T = SemaRef.Context.IntTy;
109    }
110  }
111
112  // Create the new typedef
113  TypedefDecl *Typedef
114    = TypedefDecl::Create(SemaRef.Context, Owner, D->getLocation(),
115                          D->getIdentifier(), T);
116  if (Invalid)
117    Typedef->setInvalidDecl();
118
119  Owner->addDecl(Typedef);
120
121  return Typedef;
122}
123
124Decl *TemplateDeclInstantiator::VisitVarDecl(VarDecl *D) {
125  // Do substitution on the type of the declaration
126  DeclaratorInfo *DI = SemaRef.SubstType(D->getDeclaratorInfo(),
127                                         TemplateArgs,
128                                         D->getTypeSpecStartLoc(),
129                                         D->getDeclName());
130  if (!DI)
131    return 0;
132
133  // Build the instantiated declaration
134  VarDecl *Var = VarDecl::Create(SemaRef.Context, Owner,
135                                 D->getLocation(), D->getIdentifier(),
136                                 DI->getType(), DI,
137                                 D->getStorageClass());
138  Var->setThreadSpecified(D->isThreadSpecified());
139  Var->setCXXDirectInitializer(D->hasCXXDirectInitializer());
140  Var->setDeclaredInCondition(D->isDeclaredInCondition());
141
142  // If we are instantiating a static data member defined
143  // out-of-line, the instantiation will have the same lexical
144  // context (which will be a namespace scope) as the template.
145  if (D->isOutOfLine())
146    Var->setLexicalDeclContext(D->getLexicalDeclContext());
147
148  // FIXME: In theory, we could have a previous declaration for variables that
149  // are not static data members.
150  bool Redeclaration = false;
151  SemaRef.CheckVariableDeclaration(Var, 0, Redeclaration);
152
153  if (D->isOutOfLine()) {
154    D->getLexicalDeclContext()->addDecl(Var);
155    Owner->makeDeclVisibleInContext(Var);
156  } else {
157    Owner->addDecl(Var);
158  }
159
160  // Link instantiations of static data members back to the template from
161  // which they were instantiated.
162  if (Var->isStaticDataMember())
163    SemaRef.Context.setInstantiatedFromStaticDataMember(Var, D,
164                                                        TSK_ImplicitInstantiation);
165
166  if (D->getInit()) {
167    OwningExprResult Init
168      = SemaRef.SubstExpr(D->getInit(), TemplateArgs);
169    if (Init.isInvalid())
170      Var->setInvalidDecl();
171    else if (ParenListExpr *PLE = dyn_cast<ParenListExpr>((Expr *)Init.get())) {
172      // FIXME: We're faking all of the comma locations, which is suboptimal.
173      // Do we even need these comma locations?
174      llvm::SmallVector<SourceLocation, 4> FakeCommaLocs;
175      if (PLE->getNumExprs() > 0) {
176        FakeCommaLocs.reserve(PLE->getNumExprs() - 1);
177        for (unsigned I = 0, N = PLE->getNumExprs() - 1; I != N; ++I) {
178          Expr *E = PLE->getExpr(I)->Retain();
179          FakeCommaLocs.push_back(
180                                SemaRef.PP.getLocForEndOfToken(E->getLocEnd()));
181        }
182        PLE->getExpr(PLE->getNumExprs() - 1)->Retain();
183      }
184
185      // Add the direct initializer to the declaration.
186      SemaRef.AddCXXDirectInitializerToDecl(Sema::DeclPtrTy::make(Var),
187                                            PLE->getLParenLoc(),
188                                            Sema::MultiExprArg(SemaRef,
189                                                       (void**)PLE->getExprs(),
190                                                           PLE->getNumExprs()),
191                                            FakeCommaLocs.data(),
192                                            PLE->getRParenLoc());
193
194      // When Init is destroyed, it will destroy the instantiated ParenListExpr;
195      // we've explicitly retained all of its subexpressions already.
196    } else
197      SemaRef.AddInitializerToDecl(Sema::DeclPtrTy::make(Var), move(Init),
198                                   D->hasCXXDirectInitializer());
199  } else if (!Var->isStaticDataMember() || Var->isOutOfLine())
200    SemaRef.ActOnUninitializedDecl(Sema::DeclPtrTy::make(Var), false);
201
202  return Var;
203}
204
205Decl *TemplateDeclInstantiator::VisitFieldDecl(FieldDecl *D) {
206  bool Invalid = false;
207  DeclaratorInfo *DI = D->getDeclaratorInfo();
208  if (DI->getType()->isDependentType())  {
209    DI = SemaRef.SubstType(DI, TemplateArgs,
210                           D->getLocation(), D->getDeclName());
211    if (DI && DI->getType()->isFunctionType()) {
212      // C++ [temp.arg.type]p3:
213      //   If a declaration acquires a function type through a type
214      //   dependent on a template-parameter and this causes a
215      //   declaration that does not use the syntactic form of a
216      //   function declarator to have function type, the program is
217      //   ill-formed.
218      SemaRef.Diag(D->getLocation(), diag::err_field_instantiates_to_function)
219        << T;
220      T = QualType();
221      Invalid = true;
222    }
223  }
224
225  Expr *BitWidth = D->getBitWidth();
226  if (Invalid)
227    BitWidth = 0;
228  else if (BitWidth) {
229    // The bit-width expression is not potentially evaluated.
230    EnterExpressionEvaluationContext Unevaluated(SemaRef, Action::Unevaluated);
231
232    OwningExprResult InstantiatedBitWidth
233      = SemaRef.SubstExpr(BitWidth, TemplateArgs);
234    if (InstantiatedBitWidth.isInvalid()) {
235      Invalid = true;
236      BitWidth = 0;
237    } else
238      BitWidth = InstantiatedBitWidth.takeAs<Expr>();
239  }
240
241  FieldDecl *Field = SemaRef.CheckFieldDecl(D->getDeclName(),
242                                            DI->getType(), DI,
243                                            cast<RecordDecl>(Owner),
244                                            D->getLocation(),
245                                            D->isMutable(),
246                                            BitWidth,
247                                            D->getTypeSpecStartLoc(),
248                                            D->getAccess(),
249                                            0);
250  if (!Field) {
251    cast<Decl>(Owner)->setInvalidDecl();
252    return 0;
253  }
254
255  if (Invalid)
256    Field->setInvalidDecl();
257
258  if (!Field->getDeclName()) {
259    // Keep track of where this decl came from.
260    SemaRef.Context.setInstantiatedFromUnnamedFieldDecl(Field, D);
261  }
262
263  Field->setImplicit(D->isImplicit());
264  Owner->addDecl(Field);
265
266  return Field;
267}
268
269Decl *TemplateDeclInstantiator::VisitFriendDecl(FriendDecl *D) {
270  FriendDecl::FriendUnion FU;
271
272  // Handle friend type expressions by simply substituting template
273  // parameters into the pattern type.
274  if (Type *Ty = D->getFriendType()) {
275    QualType T = SemaRef.SubstType(QualType(Ty,0), TemplateArgs,
276                                   D->getLocation(), DeclarationName());
277    if (T.isNull()) return 0;
278
279    assert(getLangOptions().CPlusPlus0x || T->isRecordType());
280    FU = T.getTypePtr();
281
282  // Handle everything else by appropriate substitution.
283  } else {
284    NamedDecl *ND = D->getFriendDecl();
285    assert(ND && "friend decl must be a decl or a type!");
286
287    // FIXME: We have a problem here, because the nested call to Visit(ND)
288    // will inject the thing that the friend references into the current
289    // owner, which is wrong.
290    Decl *NewND = Visit(ND);
291    if (!NewND) return 0;
292
293    FU = cast<NamedDecl>(NewND);
294  }
295
296  FriendDecl *FD =
297    FriendDecl::Create(SemaRef.Context, Owner, D->getLocation(), FU,
298                       D->getFriendLoc());
299  FD->setAccess(AS_public);
300  Owner->addDecl(FD);
301  return FD;
302}
303
304Decl *TemplateDeclInstantiator::VisitStaticAssertDecl(StaticAssertDecl *D) {
305  Expr *AssertExpr = D->getAssertExpr();
306
307  // The expression in a static assertion is not potentially evaluated.
308  EnterExpressionEvaluationContext Unevaluated(SemaRef, Action::Unevaluated);
309
310  OwningExprResult InstantiatedAssertExpr
311    = SemaRef.SubstExpr(AssertExpr, TemplateArgs);
312  if (InstantiatedAssertExpr.isInvalid())
313    return 0;
314
315  OwningExprResult Message(SemaRef, D->getMessage());
316  D->getMessage()->Retain();
317  Decl *StaticAssert
318    = SemaRef.ActOnStaticAssertDeclaration(D->getLocation(),
319                                           move(InstantiatedAssertExpr),
320                                           move(Message)).getAs<Decl>();
321  return StaticAssert;
322}
323
324Decl *TemplateDeclInstantiator::VisitEnumDecl(EnumDecl *D) {
325  EnumDecl *Enum = EnumDecl::Create(SemaRef.Context, Owner,
326                                    D->getLocation(), D->getIdentifier(),
327                                    D->getTagKeywordLoc(),
328                                    /*PrevDecl=*/0);
329  Enum->setInstantiationOfMemberEnum(D);
330  Enum->setAccess(D->getAccess());
331  Owner->addDecl(Enum);
332  Enum->startDefinition();
333
334  llvm::SmallVector<Sema::DeclPtrTy, 4> Enumerators;
335
336  EnumConstantDecl *LastEnumConst = 0;
337  for (EnumDecl::enumerator_iterator EC = D->enumerator_begin(),
338         ECEnd = D->enumerator_end();
339       EC != ECEnd; ++EC) {
340    // The specified value for the enumerator.
341    OwningExprResult Value = SemaRef.Owned((Expr *)0);
342    if (Expr *UninstValue = EC->getInitExpr()) {
343      // The enumerator's value expression is not potentially evaluated.
344      EnterExpressionEvaluationContext Unevaluated(SemaRef,
345                                                   Action::Unevaluated);
346
347      Value = SemaRef.SubstExpr(UninstValue, TemplateArgs);
348    }
349
350    // Drop the initial value and continue.
351    bool isInvalid = false;
352    if (Value.isInvalid()) {
353      Value = SemaRef.Owned((Expr *)0);
354      isInvalid = true;
355    }
356
357    EnumConstantDecl *EnumConst
358      = SemaRef.CheckEnumConstant(Enum, LastEnumConst,
359                                  EC->getLocation(), EC->getIdentifier(),
360                                  move(Value));
361
362    if (isInvalid) {
363      if (EnumConst)
364        EnumConst->setInvalidDecl();
365      Enum->setInvalidDecl();
366    }
367
368    if (EnumConst) {
369      Enum->addDecl(EnumConst);
370      Enumerators.push_back(Sema::DeclPtrTy::make(EnumConst));
371      LastEnumConst = EnumConst;
372    }
373  }
374
375  // FIXME: Fixup LBraceLoc and RBraceLoc
376  // FIXME: Empty Scope and AttributeList (required to handle attribute packed).
377  SemaRef.ActOnEnumBody(Enum->getLocation(), SourceLocation(), SourceLocation(),
378                        Sema::DeclPtrTy::make(Enum),
379                        &Enumerators[0], Enumerators.size(),
380                        0, 0);
381
382  return Enum;
383}
384
385Decl *TemplateDeclInstantiator::VisitEnumConstantDecl(EnumConstantDecl *D) {
386  assert(false && "EnumConstantDecls can only occur within EnumDecls.");
387  return 0;
388}
389
390Decl *TemplateDeclInstantiator::VisitClassTemplateDecl(ClassTemplateDecl *D) {
391  TemplateParameterList *TempParams = D->getTemplateParameters();
392  TemplateParameterList *InstParams = SubstTemplateParams(TempParams);
393  if (!InstParams)
394    return NULL;
395
396  CXXRecordDecl *Pattern = D->getTemplatedDecl();
397  CXXRecordDecl *RecordInst
398    = CXXRecordDecl::Create(SemaRef.Context, Pattern->getTagKind(), Owner,
399                            Pattern->getLocation(), Pattern->getIdentifier(),
400                            Pattern->getTagKeywordLoc(), /*PrevDecl=*/ NULL,
401                            /*DelayTypeCreation=*/true);
402
403  ClassTemplateDecl *Inst
404    = ClassTemplateDecl::Create(SemaRef.Context, Owner, D->getLocation(),
405                                D->getIdentifier(), InstParams, RecordInst, 0);
406  RecordInst->setDescribedClassTemplate(Inst);
407  Inst->setAccess(D->getAccess());
408  Inst->setInstantiatedFromMemberTemplate(D);
409
410  // Trigger creation of the type for the instantiation.
411  SemaRef.Context.getTypeDeclType(RecordInst);
412
413  Owner->addDecl(Inst);
414  return Inst;
415}
416
417Decl *
418TemplateDeclInstantiator::VisitClassTemplatePartialSpecializationDecl(
419                                   ClassTemplatePartialSpecializationDecl *D) {
420  assert(false &&"Partial specializations of member templates are unsupported");
421  return 0;
422}
423
424Decl *
425TemplateDeclInstantiator::VisitFunctionTemplateDecl(FunctionTemplateDecl *D) {
426  // FIXME: Dig out the out-of-line definition of this function template?
427
428  TemplateParameterList *TempParams = D->getTemplateParameters();
429  TemplateParameterList *InstParams = SubstTemplateParams(TempParams);
430  if (!InstParams)
431    return NULL;
432
433  FunctionDecl *Instantiated = 0;
434  if (CXXMethodDecl *DMethod = dyn_cast<CXXMethodDecl>(D->getTemplatedDecl()))
435    Instantiated = cast_or_null<FunctionDecl>(VisitCXXMethodDecl(DMethod,
436                                                                 InstParams));
437  else
438    Instantiated = cast_or_null<FunctionDecl>(VisitFunctionDecl(
439                                                          D->getTemplatedDecl(),
440                                                                InstParams));
441
442  if (!Instantiated)
443    return 0;
444
445  // Link the instantiated function template declaration to the function
446  // template from which it was instantiated.
447  FunctionTemplateDecl *InstTemplate
448    = Instantiated->getDescribedFunctionTemplate();
449  InstTemplate->setAccess(D->getAccess());
450  assert(InstTemplate &&
451         "VisitFunctionDecl/CXXMethodDecl didn't create a template!");
452  if (!InstTemplate->getInstantiatedFromMemberTemplate())
453    InstTemplate->setInstantiatedFromMemberTemplate(D);
454
455  // Add non-friends into the owner.
456  if (!InstTemplate->getFriendObjectKind())
457    Owner->addDecl(InstTemplate);
458  return InstTemplate;
459}
460
461Decl *TemplateDeclInstantiator::VisitCXXRecordDecl(CXXRecordDecl *D) {
462  CXXRecordDecl *PrevDecl = 0;
463  if (D->isInjectedClassName())
464    PrevDecl = cast<CXXRecordDecl>(Owner);
465
466  CXXRecordDecl *Record
467    = CXXRecordDecl::Create(SemaRef.Context, D->getTagKind(), Owner,
468                            D->getLocation(), D->getIdentifier(),
469                            D->getTagKeywordLoc(), PrevDecl);
470  Record->setImplicit(D->isImplicit());
471  // FIXME: Check against AS_none is an ugly hack to work around the issue that
472  // the tag decls introduced by friend class declarations don't have an access
473  // specifier. Remove once this area of the code gets sorted out.
474  if (D->getAccess() != AS_none)
475    Record->setAccess(D->getAccess());
476  if (!D->isInjectedClassName())
477    Record->setInstantiationOfMemberClass(D, TSK_ImplicitInstantiation);
478
479  // If the original function was part of a friend declaration,
480  // inherit its namespace state.
481  if (Decl::FriendObjectKind FOK = D->getFriendObjectKind())
482    Record->setObjectOfFriendDecl(FOK == Decl::FOK_Declared);
483
484  Record->setAnonymousStructOrUnion(D->isAnonymousStructOrUnion());
485
486  Owner->addDecl(Record);
487  return Record;
488}
489
490/// Normal class members are of more specific types and therefore
491/// don't make it here.  This function serves two purposes:
492///   1) instantiating function templates
493///   2) substituting friend declarations
494/// FIXME: preserve function definitions in case #2
495  Decl *TemplateDeclInstantiator::VisitFunctionDecl(FunctionDecl *D,
496                                       TemplateParameterList *TemplateParams) {
497  // Check whether there is already a function template specialization for
498  // this declaration.
499  FunctionTemplateDecl *FunctionTemplate = D->getDescribedFunctionTemplate();
500  void *InsertPos = 0;
501  if (FunctionTemplate && !TemplateParams) {
502    llvm::FoldingSetNodeID ID;
503    FunctionTemplateSpecializationInfo::Profile(ID,
504                             TemplateArgs.getInnermost().getFlatArgumentList(),
505                                       TemplateArgs.getInnermost().flat_size(),
506                                                SemaRef.Context);
507
508    FunctionTemplateSpecializationInfo *Info
509      = FunctionTemplate->getSpecializations().FindNodeOrInsertPos(ID,
510                                                                   InsertPos);
511
512    // If we already have a function template specialization, return it.
513    if (Info)
514      return Info->Function;
515  }
516
517  Sema::LocalInstantiationScope Scope(SemaRef);
518
519  llvm::SmallVector<ParmVarDecl *, 4> Params;
520  QualType T = SubstFunctionType(D, Params);
521  if (T.isNull())
522    return 0;
523
524  // Build the instantiated method declaration.
525  DeclContext *DC = SemaRef.FindInstantiatedContext(D->getDeclContext(),
526                                                    TemplateArgs);
527  FunctionDecl *Function =
528      FunctionDecl::Create(SemaRef.Context, DC, D->getLocation(),
529                           D->getDeclName(), T, D->getDeclaratorInfo(),
530                           D->getStorageClass(),
531                           D->isInline(), D->hasWrittenPrototype());
532  Function->setLexicalDeclContext(Owner);
533
534  // Attach the parameters
535  for (unsigned P = 0; P < Params.size(); ++P)
536    Params[P]->setOwningFunction(Function);
537  Function->setParams(SemaRef.Context, Params.data(), Params.size());
538
539  if (TemplateParams) {
540    // Our resulting instantiation is actually a function template, since we
541    // are substituting only the outer template parameters. For example, given
542    //
543    //   template<typename T>
544    //   struct X {
545    //     template<typename U> friend void f(T, U);
546    //   };
547    //
548    //   X<int> x;
549    //
550    // We are instantiating the friend function template "f" within X<int>,
551    // which means substituting int for T, but leaving "f" as a friend function
552    // template.
553    // Build the function template itself.
554    FunctionTemplate = FunctionTemplateDecl::Create(SemaRef.Context, Owner,
555                                                    Function->getLocation(),
556                                                    Function->getDeclName(),
557                                                    TemplateParams, Function);
558    Function->setDescribedFunctionTemplate(FunctionTemplate);
559    FunctionTemplate->setLexicalDeclContext(D->getLexicalDeclContext());
560  }
561
562  if (InitFunctionInstantiation(Function, D))
563    Function->setInvalidDecl();
564
565  bool Redeclaration = false;
566  bool OverloadableAttrRequired = false;
567
568  NamedDecl *PrevDecl = 0;
569  if (TemplateParams || !FunctionTemplate) {
570    // Look only into the namespace where the friend would be declared to
571    // find a previous declaration. This is the innermost enclosing namespace,
572    // as described in ActOnFriendFunctionDecl.
573    Sema::LookupResult R;
574    SemaRef.LookupQualifiedName(R, DC, Function->getDeclName(),
575                              Sema::LookupOrdinaryName, true);
576
577    PrevDecl = R.getAsSingleDecl(SemaRef.Context);
578
579    // In C++, the previous declaration we find might be a tag type
580    // (class or enum). In this case, the new declaration will hide the
581    // tag type. Note that this does does not apply if we're declaring a
582    // typedef (C++ [dcl.typedef]p4).
583    if (PrevDecl && PrevDecl->getIdentifierNamespace() == Decl::IDNS_Tag)
584      PrevDecl = 0;
585  }
586
587  SemaRef.CheckFunctionDeclaration(Function, PrevDecl, false, Redeclaration,
588                                   /*FIXME:*/OverloadableAttrRequired);
589
590  // If the original function was part of a friend declaration,
591  // inherit its namespace state and add it to the owner.
592  NamedDecl *FromFriendD
593      = TemplateParams? cast<NamedDecl>(D->getDescribedFunctionTemplate()) : D;
594  if (FromFriendD->getFriendObjectKind()) {
595    NamedDecl *ToFriendD = 0;
596    if (TemplateParams) {
597      ToFriendD = cast<NamedDecl>(FunctionTemplate);
598      PrevDecl = FunctionTemplate->getPreviousDeclaration();
599    } else {
600      ToFriendD = Function;
601      PrevDecl = Function->getPreviousDeclaration();
602    }
603    ToFriendD->setObjectOfFriendDecl(PrevDecl != NULL);
604    if (!Owner->isDependentContext() && !PrevDecl)
605      DC->makeDeclVisibleInContext(ToFriendD, /* Recoverable = */ false);
606
607    if (!TemplateParams)
608      Function->setInstantiationOfMemberFunction(D, TSK_ImplicitInstantiation);
609  }
610
611  if (FunctionTemplate && !TemplateParams) {
612    // Record this function template specialization.
613    Function->setFunctionTemplateSpecialization(SemaRef.Context,
614                                                FunctionTemplate,
615                                                &TemplateArgs.getInnermost(),
616                                                InsertPos);
617  }
618
619  return Function;
620}
621
622Decl *
623TemplateDeclInstantiator::VisitCXXMethodDecl(CXXMethodDecl *D,
624                                      TemplateParameterList *TemplateParams) {
625  FunctionTemplateDecl *FunctionTemplate = D->getDescribedFunctionTemplate();
626  void *InsertPos = 0;
627  if (FunctionTemplate && !TemplateParams) {
628    // We are creating a function template specialization from a function
629    // template. Check whether there is already a function template
630    // specialization for this particular set of template arguments.
631    llvm::FoldingSetNodeID ID;
632    FunctionTemplateSpecializationInfo::Profile(ID,
633                            TemplateArgs.getInnermost().getFlatArgumentList(),
634                                      TemplateArgs.getInnermost().flat_size(),
635                                                SemaRef.Context);
636
637    FunctionTemplateSpecializationInfo *Info
638      = FunctionTemplate->getSpecializations().FindNodeOrInsertPos(ID,
639                                                                   InsertPos);
640
641    // If we already have a function template specialization, return it.
642    if (Info)
643      return Info->Function;
644  }
645
646  Sema::LocalInstantiationScope Scope(SemaRef);
647
648  llvm::SmallVector<ParmVarDecl *, 4> Params;
649  QualType T = SubstFunctionType(D, Params);
650  if (T.isNull())
651    return 0;
652
653  // Build the instantiated method declaration.
654  CXXRecordDecl *Record = cast<CXXRecordDecl>(Owner);
655  CXXMethodDecl *Method = 0;
656
657  DeclarationName Name = D->getDeclName();
658  if (CXXConstructorDecl *Constructor = dyn_cast<CXXConstructorDecl>(D)) {
659    QualType ClassTy = SemaRef.Context.getTypeDeclType(Record);
660    Name = SemaRef.Context.DeclarationNames.getCXXConstructorName(
661                                    SemaRef.Context.getCanonicalType(ClassTy));
662    Method = CXXConstructorDecl::Create(SemaRef.Context, Record,
663                                        Constructor->getLocation(),
664                                        Name, T,
665                                        Constructor->getDeclaratorInfo(),
666                                        Constructor->isExplicit(),
667                                        Constructor->isInline(), false);
668  } else if (CXXDestructorDecl *Destructor = dyn_cast<CXXDestructorDecl>(D)) {
669    QualType ClassTy = SemaRef.Context.getTypeDeclType(Record);
670    Name = SemaRef.Context.DeclarationNames.getCXXDestructorName(
671                                   SemaRef.Context.getCanonicalType(ClassTy));
672    Method = CXXDestructorDecl::Create(SemaRef.Context, Record,
673                                       Destructor->getLocation(), Name,
674                                       T, Destructor->isInline(), false);
675  } else if (CXXConversionDecl *Conversion = dyn_cast<CXXConversionDecl>(D)) {
676    CanQualType ConvTy
677      = SemaRef.Context.getCanonicalType(
678                                      T->getAs<FunctionType>()->getResultType());
679    Name = SemaRef.Context.DeclarationNames.getCXXConversionFunctionName(
680                                                                      ConvTy);
681    Method = CXXConversionDecl::Create(SemaRef.Context, Record,
682                                       Conversion->getLocation(), Name,
683                                       T, Conversion->getDeclaratorInfo(),
684                                       Conversion->isInline(),
685                                       Conversion->isExplicit());
686  } else {
687    Method = CXXMethodDecl::Create(SemaRef.Context, Record, D->getLocation(),
688                                   D->getDeclName(), T, D->getDeclaratorInfo(),
689                                   D->isStatic(), D->isInline());
690  }
691
692  if (TemplateParams) {
693    // Our resulting instantiation is actually a function template, since we
694    // are substituting only the outer template parameters. For example, given
695    //
696    //   template<typename T>
697    //   struct X {
698    //     template<typename U> void f(T, U);
699    //   };
700    //
701    //   X<int> x;
702    //
703    // We are instantiating the member template "f" within X<int>, which means
704    // substituting int for T, but leaving "f" as a member function template.
705    // Build the function template itself.
706    FunctionTemplate = FunctionTemplateDecl::Create(SemaRef.Context, Record,
707                                                    Method->getLocation(),
708                                                    Method->getDeclName(),
709                                                    TemplateParams, Method);
710    if (D->isOutOfLine())
711      FunctionTemplate->setLexicalDeclContext(D->getLexicalDeclContext());
712    Method->setDescribedFunctionTemplate(FunctionTemplate);
713  } else if (!FunctionTemplate)
714    Method->setInstantiationOfMemberFunction(D, TSK_ImplicitInstantiation);
715
716  // If we are instantiating a member function defined
717  // out-of-line, the instantiation will have the same lexical
718  // context (which will be a namespace scope) as the template.
719  if (D->isOutOfLine())
720    Method->setLexicalDeclContext(D->getLexicalDeclContext());
721
722  // Attach the parameters
723  for (unsigned P = 0; P < Params.size(); ++P)
724    Params[P]->setOwningFunction(Method);
725  Method->setParams(SemaRef.Context, Params.data(), Params.size());
726
727  if (InitMethodInstantiation(Method, D))
728    Method->setInvalidDecl();
729
730  NamedDecl *PrevDecl = 0;
731
732  if (!FunctionTemplate || TemplateParams) {
733    Sema::LookupResult R;
734    SemaRef.LookupQualifiedName(R, Owner, Name, Sema::LookupOrdinaryName, true);
735    PrevDecl = R.getAsSingleDecl(SemaRef.Context);
736
737    // In C++, the previous declaration we find might be a tag type
738    // (class or enum). In this case, the new declaration will hide the
739    // tag type. Note that this does does not apply if we're declaring a
740    // typedef (C++ [dcl.typedef]p4).
741    if (PrevDecl && PrevDecl->getIdentifierNamespace() == Decl::IDNS_Tag)
742      PrevDecl = 0;
743  }
744
745  if (FunctionTemplate && !TemplateParams)
746    // Record this function template specialization.
747    Method->setFunctionTemplateSpecialization(SemaRef.Context,
748                                              FunctionTemplate,
749                                              &TemplateArgs.getInnermost(),
750                                              InsertPos);
751
752  bool Redeclaration = false;
753  bool OverloadableAttrRequired = false;
754  SemaRef.CheckFunctionDeclaration(Method, PrevDecl, false, Redeclaration,
755                                   /*FIXME:*/OverloadableAttrRequired);
756
757  if (!FunctionTemplate && (!Method->isInvalidDecl() || !PrevDecl) &&
758      !Method->getFriendObjectKind())
759    Owner->addDecl(Method);
760
761  return Method;
762}
763
764Decl *TemplateDeclInstantiator::VisitCXXConstructorDecl(CXXConstructorDecl *D) {
765  return VisitCXXMethodDecl(D);
766}
767
768Decl *TemplateDeclInstantiator::VisitCXXDestructorDecl(CXXDestructorDecl *D) {
769  return VisitCXXMethodDecl(D);
770}
771
772Decl *TemplateDeclInstantiator::VisitCXXConversionDecl(CXXConversionDecl *D) {
773  return VisitCXXMethodDecl(D);
774}
775
776ParmVarDecl *TemplateDeclInstantiator::VisitParmVarDecl(ParmVarDecl *D) {
777  QualType OrigT = SemaRef.SubstType(D->getOriginalType(), TemplateArgs,
778                                           D->getLocation(), D->getDeclName());
779  if (OrigT.isNull())
780    return 0;
781
782  QualType T = SemaRef.adjustParameterType(OrigT);
783
784  // Allocate the parameter
785  ParmVarDecl *Param = 0;
786  if (T == OrigT)
787    Param = ParmVarDecl::Create(SemaRef.Context, Owner, D->getLocation(),
788                                D->getIdentifier(), T, D->getDeclaratorInfo(),
789                                D->getStorageClass(), 0);
790  else
791    Param = OriginalParmVarDecl::Create(SemaRef.Context, Owner,
792                                        D->getLocation(), D->getIdentifier(),
793                                        T, D->getDeclaratorInfo(), OrigT,
794                                        D->getStorageClass(), 0);
795
796  // Mark the default argument as being uninstantiated.
797  if (D->hasUninstantiatedDefaultArg())
798    Param->setUninstantiatedDefaultArg(D->getUninstantiatedDefaultArg());
799  else if (Expr *Arg = D->getDefaultArg())
800    Param->setUninstantiatedDefaultArg(Arg);
801
802  // Note: we don't try to instantiate function parameters until after
803  // we've instantiated the function's type. Therefore, we don't have
804  // to check for 'void' parameter types here.
805  SemaRef.CurrentInstantiationScope->InstantiatedLocal(D, Param);
806  return Param;
807}
808
809Decl *
810TemplateDeclInstantiator::VisitOriginalParmVarDecl(OriginalParmVarDecl *D) {
811  // Since parameter types can decay either before or after
812  // instantiation, we simply treat OriginalParmVarDecls as
813  // ParmVarDecls the same way, and create one or the other depending
814  // on what happens after template instantiation.
815  return VisitParmVarDecl(D);
816}
817
818Decl *TemplateDeclInstantiator::VisitTemplateTypeParmDecl(
819                                                    TemplateTypeParmDecl *D) {
820  // TODO: don't always clone when decls are refcounted.
821  const Type* T = D->getTypeForDecl();
822  assert(T->isTemplateTypeParmType());
823  const TemplateTypeParmType *TTPT = T->getAs<TemplateTypeParmType>();
824
825  TemplateTypeParmDecl *Inst =
826    TemplateTypeParmDecl::Create(SemaRef.Context, Owner, D->getLocation(),
827                                 TTPT->getDepth(), TTPT->getIndex(),
828                                 TTPT->getName(),
829                                 D->wasDeclaredWithTypename(),
830                                 D->isParameterPack());
831
832  if (D->hasDefaultArgument()) {
833    QualType DefaultPattern = D->getDefaultArgument();
834    QualType DefaultInst
835      = SemaRef.SubstType(DefaultPattern, TemplateArgs,
836                          D->getDefaultArgumentLoc(),
837                          D->getDeclName());
838
839    Inst->setDefaultArgument(DefaultInst,
840                             D->getDefaultArgumentLoc(),
841                             D->defaultArgumentWasInherited() /* preserve? */);
842  }
843
844  return Inst;
845}
846
847Decl *
848TemplateDeclInstantiator::VisitUnresolvedUsingDecl(UnresolvedUsingDecl *D) {
849  NestedNameSpecifier *NNS =
850    SemaRef.SubstNestedNameSpecifier(D->getTargetNestedNameSpecifier(),
851                                     D->getTargetNestedNameRange(),
852                                     TemplateArgs);
853  if (!NNS)
854    return 0;
855
856  CXXScopeSpec SS;
857  SS.setRange(D->getTargetNestedNameRange());
858  SS.setScopeRep(NNS);
859
860  NamedDecl *UD =
861    SemaRef.BuildUsingDeclaration(D->getLocation(), SS,
862                                  D->getTargetNameLocation(),
863                                  D->getTargetName(), 0, D->isTypeName());
864  if (UD)
865    SemaRef.Context.setInstantiatedFromUnresolvedUsingDecl(cast<UsingDecl>(UD),
866                                                           D);
867  return UD;
868}
869
870Decl *Sema::SubstDecl(Decl *D, DeclContext *Owner,
871                      const MultiLevelTemplateArgumentList &TemplateArgs) {
872  TemplateDeclInstantiator Instantiator(*this, Owner, TemplateArgs);
873  return Instantiator.Visit(D);
874}
875
876/// \brief Instantiates a nested template parameter list in the current
877/// instantiation context.
878///
879/// \param L The parameter list to instantiate
880///
881/// \returns NULL if there was an error
882TemplateParameterList *
883TemplateDeclInstantiator::SubstTemplateParams(TemplateParameterList *L) {
884  // Get errors for all the parameters before bailing out.
885  bool Invalid = false;
886
887  unsigned N = L->size();
888  typedef llvm::SmallVector<NamedDecl *, 8> ParamVector;
889  ParamVector Params;
890  Params.reserve(N);
891  for (TemplateParameterList::iterator PI = L->begin(), PE = L->end();
892       PI != PE; ++PI) {
893    NamedDecl *D = cast_or_null<NamedDecl>(Visit(*PI));
894    Params.push_back(D);
895    Invalid = Invalid || !D;
896  }
897
898  // Clean up if we had an error.
899  if (Invalid) {
900    for (ParamVector::iterator PI = Params.begin(), PE = Params.end();
901         PI != PE; ++PI)
902      if (*PI)
903        (*PI)->Destroy(SemaRef.Context);
904    return NULL;
905  }
906
907  TemplateParameterList *InstL
908    = TemplateParameterList::Create(SemaRef.Context, L->getTemplateLoc(),
909                                    L->getLAngleLoc(), &Params.front(), N,
910                                    L->getRAngleLoc());
911  return InstL;
912}
913
914/// \brief Does substitution on the type of the given function, including
915/// all of the function parameters.
916///
917/// \param D The function whose type will be the basis of the substitution
918///
919/// \param Params the instantiated parameter declarations
920
921/// \returns the instantiated function's type if successful, a NULL
922/// type if there was an error.
923QualType
924TemplateDeclInstantiator::SubstFunctionType(FunctionDecl *D,
925                              llvm::SmallVectorImpl<ParmVarDecl *> &Params) {
926  bool InvalidDecl = false;
927
928  // Substitute all of the function's formal parameter types.
929  TemplateDeclInstantiator ParamInstantiator(SemaRef, 0, TemplateArgs);
930  llvm::SmallVector<QualType, 4> ParamTys;
931  for (FunctionDecl::param_iterator P = D->param_begin(),
932                                 PEnd = D->param_end();
933       P != PEnd; ++P) {
934    if (ParmVarDecl *PInst = ParamInstantiator.VisitParmVarDecl(*P)) {
935      if (PInst->getType()->isVoidType()) {
936        SemaRef.Diag(PInst->getLocation(), diag::err_param_with_void_type);
937        PInst->setInvalidDecl();
938      } else if (SemaRef.RequireNonAbstractType(PInst->getLocation(),
939                                                PInst->getType(),
940                                                diag::err_abstract_type_in_decl,
941                                                Sema::AbstractParamType))
942        PInst->setInvalidDecl();
943
944      Params.push_back(PInst);
945      ParamTys.push_back(PInst->getType());
946
947      if (PInst->isInvalidDecl())
948        InvalidDecl = true;
949    } else
950      InvalidDecl = true;
951  }
952
953  // FIXME: Deallocate dead declarations.
954  if (InvalidDecl)
955    return QualType();
956
957  const FunctionProtoType *Proto = D->getType()->getAs<FunctionProtoType>();
958  assert(Proto && "Missing prototype?");
959  QualType ResultType
960    = SemaRef.SubstType(Proto->getResultType(), TemplateArgs,
961                        D->getLocation(), D->getDeclName());
962  if (ResultType.isNull())
963    return QualType();
964
965  return SemaRef.BuildFunctionType(ResultType, ParamTys.data(), ParamTys.size(),
966                                   Proto->isVariadic(), Proto->getTypeQuals(),
967                                   D->getLocation(), D->getDeclName());
968}
969
970/// \brief Initializes the common fields of an instantiation function
971/// declaration (New) from the corresponding fields of its template (Tmpl).
972///
973/// \returns true if there was an error
974bool
975TemplateDeclInstantiator::InitFunctionInstantiation(FunctionDecl *New,
976                                                    FunctionDecl *Tmpl) {
977  if (Tmpl->isDeleted())
978    New->setDeleted();
979
980  // If we are performing substituting explicitly-specified template arguments
981  // or deduced template arguments into a function template and we reach this
982  // point, we are now past the point where SFINAE applies and have committed
983  // to keeping the new function template specialization. We therefore
984  // convert the active template instantiation for the function template
985  // into a template instantiation for this specific function template
986  // specialization, which is not a SFINAE context, so that we diagnose any
987  // further errors in the declaration itself.
988  typedef Sema::ActiveTemplateInstantiation ActiveInstType;
989  ActiveInstType &ActiveInst = SemaRef.ActiveTemplateInstantiations.back();
990  if (ActiveInst.Kind == ActiveInstType::ExplicitTemplateArgumentSubstitution ||
991      ActiveInst.Kind == ActiveInstType::DeducedTemplateArgumentSubstitution) {
992    if (FunctionTemplateDecl *FunTmpl
993          = dyn_cast<FunctionTemplateDecl>((Decl *)ActiveInst.Entity)) {
994      assert(FunTmpl->getTemplatedDecl() == Tmpl &&
995             "Deduction from the wrong function template?");
996      (void) FunTmpl;
997      ActiveInst.Kind = ActiveInstType::TemplateInstantiation;
998      ActiveInst.Entity = reinterpret_cast<uintptr_t>(New);
999    }
1000  }
1001
1002  return false;
1003}
1004
1005/// \brief Initializes common fields of an instantiated method
1006/// declaration (New) from the corresponding fields of its template
1007/// (Tmpl).
1008///
1009/// \returns true if there was an error
1010bool
1011TemplateDeclInstantiator::InitMethodInstantiation(CXXMethodDecl *New,
1012                                                  CXXMethodDecl *Tmpl) {
1013  if (InitFunctionInstantiation(New, Tmpl))
1014    return true;
1015
1016  CXXRecordDecl *Record = cast<CXXRecordDecl>(Owner);
1017  New->setAccess(Tmpl->getAccess());
1018  if (Tmpl->isVirtualAsWritten()) {
1019    New->setVirtualAsWritten(true);
1020    Record->setAggregate(false);
1021    Record->setPOD(false);
1022    Record->setEmpty(false);
1023    Record->setPolymorphic(true);
1024  }
1025  if (Tmpl->isPure()) {
1026    New->setPure();
1027    Record->setAbstract(true);
1028  }
1029
1030  // FIXME: attributes
1031  // FIXME: New needs a pointer to Tmpl
1032  return false;
1033}
1034
1035/// \brief Instantiate the definition of the given function from its
1036/// template.
1037///
1038/// \param PointOfInstantiation the point at which the instantiation was
1039/// required. Note that this is not precisely a "point of instantiation"
1040/// for the function, but it's close.
1041///
1042/// \param Function the already-instantiated declaration of a
1043/// function template specialization or member function of a class template
1044/// specialization.
1045///
1046/// \param Recursive if true, recursively instantiates any functions that
1047/// are required by this instantiation.
1048///
1049/// \param DefinitionRequired if true, then we are performing an explicit
1050/// instantiation where the body of the function is required. Complain if
1051/// there is no such body.
1052void Sema::InstantiateFunctionDefinition(SourceLocation PointOfInstantiation,
1053                                         FunctionDecl *Function,
1054                                         bool Recursive,
1055                                         bool DefinitionRequired) {
1056  if (Function->isInvalidDecl())
1057    return;
1058
1059  assert(!Function->getBody() && "Already instantiated!");
1060
1061  // Never instantiate an explicit specialization.
1062  if (Function->getTemplateSpecializationKind() == TSK_ExplicitSpecialization)
1063    return;
1064
1065  // Find the function body that we'll be substituting.
1066  const FunctionDecl *PatternDecl = 0;
1067  if (FunctionTemplateDecl *Primary = Function->getPrimaryTemplate()) {
1068    while (Primary->getInstantiatedFromMemberTemplate()) {
1069      // If we have hit a point where the user provided a specialization of
1070      // this template, we're done looking.
1071      if (Primary->isMemberSpecialization())
1072        break;
1073
1074      Primary = Primary->getInstantiatedFromMemberTemplate();
1075    }
1076
1077    PatternDecl = Primary->getTemplatedDecl();
1078  } else
1079    PatternDecl = Function->getInstantiatedFromMemberFunction();
1080  Stmt *Pattern = 0;
1081  if (PatternDecl)
1082    Pattern = PatternDecl->getBody(PatternDecl);
1083
1084  if (!Pattern) {
1085    if (DefinitionRequired) {
1086      if (Function->getPrimaryTemplate())
1087        Diag(PointOfInstantiation,
1088             diag::err_explicit_instantiation_undefined_func_template)
1089          << Function->getPrimaryTemplate();
1090      else
1091        Diag(PointOfInstantiation,
1092             diag::err_explicit_instantiation_undefined_member)
1093          << 1 << Function->getDeclName() << Function->getDeclContext();
1094
1095      if (PatternDecl)
1096        Diag(PatternDecl->getLocation(),
1097             diag::note_explicit_instantiation_here);
1098    }
1099
1100    return;
1101  }
1102
1103  // C++0x [temp.explicit]p9:
1104  //   Except for inline functions, other explicit instantiation declarations
1105  //   have the effect of suppressing the implicit instantiation of the entity
1106  //   to which they refer.
1107  if (Function->getTemplateSpecializationKind()
1108        == TSK_ExplicitInstantiationDeclaration &&
1109      PatternDecl->isOutOfLine() && !PatternDecl->isInline())
1110    return;
1111
1112  InstantiatingTemplate Inst(*this, PointOfInstantiation, Function);
1113  if (Inst)
1114    return;
1115
1116  // If we're performing recursive template instantiation, create our own
1117  // queue of pending implicit instantiations that we will instantiate later,
1118  // while we're still within our own instantiation context.
1119  std::deque<PendingImplicitInstantiation> SavedPendingImplicitInstantiations;
1120  if (Recursive)
1121    PendingImplicitInstantiations.swap(SavedPendingImplicitInstantiations);
1122
1123  ActOnStartOfFunctionDef(0, DeclPtrTy::make(Function));
1124
1125  // Introduce a new scope where local variable instantiations will be
1126  // recorded.
1127  LocalInstantiationScope Scope(*this);
1128
1129  // Introduce the instantiated function parameters into the local
1130  // instantiation scope.
1131  for (unsigned I = 0, N = PatternDecl->getNumParams(); I != N; ++I)
1132    Scope.InstantiatedLocal(PatternDecl->getParamDecl(I),
1133                            Function->getParamDecl(I));
1134
1135  // Enter the scope of this instantiation. We don't use
1136  // PushDeclContext because we don't have a scope.
1137  DeclContext *PreviousContext = CurContext;
1138  CurContext = Function;
1139
1140  MultiLevelTemplateArgumentList TemplateArgs =
1141    getTemplateInstantiationArgs(Function);
1142
1143  // If this is a constructor, instantiate the member initializers.
1144  if (const CXXConstructorDecl *Ctor =
1145        dyn_cast<CXXConstructorDecl>(PatternDecl)) {
1146    InstantiateMemInitializers(cast<CXXConstructorDecl>(Function), Ctor,
1147                               TemplateArgs);
1148  }
1149
1150  // Instantiate the function body.
1151  OwningStmtResult Body = SubstStmt(Pattern, TemplateArgs);
1152
1153  if (Body.isInvalid())
1154    Function->setInvalidDecl();
1155
1156  ActOnFinishFunctionBody(DeclPtrTy::make(Function), move(Body),
1157                          /*IsInstantiation=*/true);
1158
1159  CurContext = PreviousContext;
1160
1161  DeclGroupRef DG(Function);
1162  Consumer.HandleTopLevelDecl(DG);
1163
1164  if (Recursive) {
1165    // Instantiate any pending implicit instantiations found during the
1166    // instantiation of this template.
1167    PerformPendingImplicitInstantiations();
1168
1169    // Restore the set of pending implicit instantiations.
1170    PendingImplicitInstantiations.swap(SavedPendingImplicitInstantiations);
1171  }
1172}
1173
1174/// \brief Instantiate the definition of the given variable from its
1175/// template.
1176///
1177/// \param PointOfInstantiation the point at which the instantiation was
1178/// required. Note that this is not precisely a "point of instantiation"
1179/// for the function, but it's close.
1180///
1181/// \param Var the already-instantiated declaration of a static member
1182/// variable of a class template specialization.
1183///
1184/// \param Recursive if true, recursively instantiates any functions that
1185/// are required by this instantiation.
1186///
1187/// \param DefinitionRequired if true, then we are performing an explicit
1188/// instantiation where an out-of-line definition of the member variable
1189/// is required. Complain if there is no such definition.
1190void Sema::InstantiateStaticDataMemberDefinition(
1191                                          SourceLocation PointOfInstantiation,
1192                                                 VarDecl *Var,
1193                                                 bool Recursive,
1194                                                 bool DefinitionRequired) {
1195  if (Var->isInvalidDecl())
1196    return;
1197
1198  // Find the out-of-line definition of this static data member.
1199  VarDecl *Def = Var->getInstantiatedFromStaticDataMember();
1200  bool FoundOutOfLineDef = false;
1201  assert(Def && "This data member was not instantiated from a template?");
1202  assert(Def->isStaticDataMember() && "Not a static data member?");
1203  for (VarDecl::redecl_iterator RD = Def->redecls_begin(),
1204                             RDEnd = Def->redecls_end();
1205       RD != RDEnd; ++RD) {
1206    if (RD->getLexicalDeclContext()->isFileContext()) {
1207      Def = *RD;
1208      FoundOutOfLineDef = true;
1209    }
1210  }
1211
1212  if (!FoundOutOfLineDef) {
1213    // We did not find an out-of-line definition of this static data member,
1214    // so we won't perform any instantiation. Rather, we rely on the user to
1215    // instantiate this definition (or provide a specialization for it) in
1216    // another translation unit.
1217    if (DefinitionRequired) {
1218      Diag(PointOfInstantiation,
1219           diag::err_explicit_instantiation_undefined_member)
1220        << 2 << Var->getDeclName() << Var->getDeclContext();
1221      Diag(Def->getLocation(), diag::note_explicit_instantiation_here);
1222    }
1223
1224    return;
1225  }
1226
1227  // Never instantiate an explicit specialization.
1228  if (Var->getTemplateSpecializationKind() == TSK_ExplicitSpecialization)
1229    return;
1230
1231  // C++0x [temp.explicit]p9:
1232  //   Except for inline functions, other explicit instantiation declarations
1233  //   have the effect of suppressing the implicit instantiation of the entity
1234  //   to which they refer.
1235  if (Var->getTemplateSpecializationKind()
1236        == TSK_ExplicitInstantiationDeclaration)
1237    return;
1238
1239  InstantiatingTemplate Inst(*this, PointOfInstantiation, Var);
1240  if (Inst)
1241    return;
1242
1243  // If we're performing recursive template instantiation, create our own
1244  // queue of pending implicit instantiations that we will instantiate later,
1245  // while we're still within our own instantiation context.
1246  std::deque<PendingImplicitInstantiation> SavedPendingImplicitInstantiations;
1247  if (Recursive)
1248    PendingImplicitInstantiations.swap(SavedPendingImplicitInstantiations);
1249
1250  // Enter the scope of this instantiation. We don't use
1251  // PushDeclContext because we don't have a scope.
1252  DeclContext *PreviousContext = CurContext;
1253  CurContext = Var->getDeclContext();
1254
1255  VarDecl *OldVar = Var;
1256  Var = cast_or_null<VarDecl>(SubstDecl(Def, Var->getDeclContext(),
1257                                          getTemplateInstantiationArgs(Var)));
1258  CurContext = PreviousContext;
1259
1260  if (Var) {
1261    Var->setPreviousDeclaration(OldVar);
1262    MemberSpecializationInfo *MSInfo = OldVar->getMemberSpecializationInfo();
1263    assert(MSInfo && "Missing member specialization information?");
1264    Var->setTemplateSpecializationKind(MSInfo->getTemplateSpecializationKind(),
1265                                       MSInfo->getPointOfInstantiation());
1266    DeclGroupRef DG(Var);
1267    Consumer.HandleTopLevelDecl(DG);
1268  }
1269
1270  if (Recursive) {
1271    // Instantiate any pending implicit instantiations found during the
1272    // instantiation of this template.
1273    PerformPendingImplicitInstantiations();
1274
1275    // Restore the set of pending implicit instantiations.
1276    PendingImplicitInstantiations.swap(SavedPendingImplicitInstantiations);
1277  }
1278}
1279
1280void
1281Sema::InstantiateMemInitializers(CXXConstructorDecl *New,
1282                                 const CXXConstructorDecl *Tmpl,
1283                           const MultiLevelTemplateArgumentList &TemplateArgs) {
1284
1285  llvm::SmallVector<MemInitTy*, 4> NewInits;
1286
1287  // Instantiate all the initializers.
1288  for (CXXConstructorDecl::init_const_iterator Inits = Tmpl->init_begin(),
1289                                            InitsEnd = Tmpl->init_end();
1290       Inits != InitsEnd; ++Inits) {
1291    CXXBaseOrMemberInitializer *Init = *Inits;
1292
1293    ASTOwningVector<&ActionBase::DeleteExpr> NewArgs(*this);
1294
1295    // Instantiate all the arguments.
1296    for (ExprIterator Args = Init->arg_begin(), ArgsEnd = Init->arg_end();
1297         Args != ArgsEnd; ++Args) {
1298      OwningExprResult NewArg = SubstExpr(*Args, TemplateArgs);
1299
1300      if (NewArg.isInvalid())
1301        New->setInvalidDecl();
1302      else
1303        NewArgs.push_back(NewArg.takeAs<Expr>());
1304    }
1305
1306    MemInitResult NewInit;
1307
1308    if (Init->isBaseInitializer()) {
1309      QualType BaseType(Init->getBaseClass(), 0);
1310      BaseType = SubstType(BaseType, TemplateArgs, Init->getSourceLocation(),
1311                           New->getDeclName());
1312
1313      NewInit = BuildBaseInitializer(BaseType,
1314                                     (Expr **)NewArgs.data(),
1315                                     NewArgs.size(),
1316                                     Init->getSourceLocation(),
1317                                     Init->getRParenLoc(),
1318                                     New->getParent());
1319    } else if (Init->isMemberInitializer()) {
1320      FieldDecl *Member;
1321
1322      // Is this an anonymous union?
1323      if (FieldDecl *UnionInit = Init->getAnonUnionMember())
1324        Member = cast<FieldDecl>(FindInstantiatedDecl(UnionInit, TemplateArgs));
1325      else
1326        Member = cast<FieldDecl>(FindInstantiatedDecl(Init->getMember(),
1327                                                      TemplateArgs));
1328
1329      NewInit = BuildMemberInitializer(Member, (Expr **)NewArgs.data(),
1330                                       NewArgs.size(),
1331                                       Init->getSourceLocation(),
1332                                       Init->getRParenLoc());
1333    }
1334
1335    if (NewInit.isInvalid())
1336      New->setInvalidDecl();
1337    else {
1338      // FIXME: It would be nice if ASTOwningVector had a release function.
1339      NewArgs.take();
1340
1341      NewInits.push_back((MemInitTy *)NewInit.get());
1342    }
1343  }
1344
1345  // Assign all the initializers to the new constructor.
1346  ActOnMemInitializers(DeclPtrTy::make(New),
1347                       /*FIXME: ColonLoc */
1348                       SourceLocation(),
1349                       NewInits.data(), NewInits.size());
1350}
1351
1352// TODO: this could be templated if the various decl types used the
1353// same method name.
1354static bool isInstantiationOf(ClassTemplateDecl *Pattern,
1355                              ClassTemplateDecl *Instance) {
1356  Pattern = Pattern->getCanonicalDecl();
1357
1358  do {
1359    Instance = Instance->getCanonicalDecl();
1360    if (Pattern == Instance) return true;
1361    Instance = Instance->getInstantiatedFromMemberTemplate();
1362  } while (Instance);
1363
1364  return false;
1365}
1366
1367static bool isInstantiationOf(FunctionTemplateDecl *Pattern,
1368                              FunctionTemplateDecl *Instance) {
1369  Pattern = Pattern->getCanonicalDecl();
1370
1371  do {
1372    Instance = Instance->getCanonicalDecl();
1373    if (Pattern == Instance) return true;
1374    Instance = Instance->getInstantiatedFromMemberTemplate();
1375  } while (Instance);
1376
1377  return false;
1378}
1379
1380static bool isInstantiationOf(CXXRecordDecl *Pattern,
1381                              CXXRecordDecl *Instance) {
1382  Pattern = Pattern->getCanonicalDecl();
1383
1384  do {
1385    Instance = Instance->getCanonicalDecl();
1386    if (Pattern == Instance) return true;
1387    Instance = Instance->getInstantiatedFromMemberClass();
1388  } while (Instance);
1389
1390  return false;
1391}
1392
1393static bool isInstantiationOf(FunctionDecl *Pattern,
1394                              FunctionDecl *Instance) {
1395  Pattern = Pattern->getCanonicalDecl();
1396
1397  do {
1398    Instance = Instance->getCanonicalDecl();
1399    if (Pattern == Instance) return true;
1400    Instance = Instance->getInstantiatedFromMemberFunction();
1401  } while (Instance);
1402
1403  return false;
1404}
1405
1406static bool isInstantiationOf(EnumDecl *Pattern,
1407                              EnumDecl *Instance) {
1408  Pattern = Pattern->getCanonicalDecl();
1409
1410  do {
1411    Instance = Instance->getCanonicalDecl();
1412    if (Pattern == Instance) return true;
1413    Instance = Instance->getInstantiatedFromMemberEnum();
1414  } while (Instance);
1415
1416  return false;
1417}
1418
1419static bool isInstantiationOf(UnresolvedUsingDecl *Pattern,
1420                              UsingDecl *Instance,
1421                              ASTContext &C) {
1422  return C.getInstantiatedFromUnresolvedUsingDecl(Instance) == Pattern;
1423}
1424
1425static bool isInstantiationOfStaticDataMember(VarDecl *Pattern,
1426                                              VarDecl *Instance) {
1427  assert(Instance->isStaticDataMember());
1428
1429  Pattern = Pattern->getCanonicalDecl();
1430
1431  do {
1432    Instance = Instance->getCanonicalDecl();
1433    if (Pattern == Instance) return true;
1434    Instance = Instance->getInstantiatedFromStaticDataMember();
1435  } while (Instance);
1436
1437  return false;
1438}
1439
1440static bool isInstantiationOf(ASTContext &Ctx, NamedDecl *D, Decl *Other) {
1441  if (D->getKind() != Other->getKind()) {
1442    if (UnresolvedUsingDecl *UUD = dyn_cast<UnresolvedUsingDecl>(D)) {
1443      if (UsingDecl *UD = dyn_cast<UsingDecl>(Other)) {
1444        return isInstantiationOf(UUD, UD, Ctx);
1445      }
1446    }
1447
1448    return false;
1449  }
1450
1451  if (CXXRecordDecl *Record = dyn_cast<CXXRecordDecl>(Other))
1452    return isInstantiationOf(cast<CXXRecordDecl>(D), Record);
1453
1454  if (FunctionDecl *Function = dyn_cast<FunctionDecl>(Other))
1455    return isInstantiationOf(cast<FunctionDecl>(D), Function);
1456
1457  if (EnumDecl *Enum = dyn_cast<EnumDecl>(Other))
1458    return isInstantiationOf(cast<EnumDecl>(D), Enum);
1459
1460  if (VarDecl *Var = dyn_cast<VarDecl>(Other))
1461    if (Var->isStaticDataMember())
1462      return isInstantiationOfStaticDataMember(cast<VarDecl>(D), Var);
1463
1464  if (ClassTemplateDecl *Temp = dyn_cast<ClassTemplateDecl>(Other))
1465    return isInstantiationOf(cast<ClassTemplateDecl>(D), Temp);
1466
1467  if (FunctionTemplateDecl *Temp = dyn_cast<FunctionTemplateDecl>(Other))
1468    return isInstantiationOf(cast<FunctionTemplateDecl>(D), Temp);
1469
1470  if (FieldDecl *Field = dyn_cast<FieldDecl>(Other)) {
1471    if (!Field->getDeclName()) {
1472      // This is an unnamed field.
1473      return Ctx.getInstantiatedFromUnnamedFieldDecl(Field) ==
1474        cast<FieldDecl>(D);
1475    }
1476  }
1477
1478  return D->getDeclName() && isa<NamedDecl>(Other) &&
1479    D->getDeclName() == cast<NamedDecl>(Other)->getDeclName();
1480}
1481
1482template<typename ForwardIterator>
1483static NamedDecl *findInstantiationOf(ASTContext &Ctx,
1484                                      NamedDecl *D,
1485                                      ForwardIterator first,
1486                                      ForwardIterator last) {
1487  for (; first != last; ++first)
1488    if (isInstantiationOf(Ctx, D, *first))
1489      return cast<NamedDecl>(*first);
1490
1491  return 0;
1492}
1493
1494/// \brief Finds the instantiation of the given declaration context
1495/// within the current instantiation.
1496///
1497/// \returns NULL if there was an error
1498DeclContext *Sema::FindInstantiatedContext(DeclContext* DC,
1499                          const MultiLevelTemplateArgumentList &TemplateArgs) {
1500  if (NamedDecl *D = dyn_cast<NamedDecl>(DC)) {
1501    Decl* ID = FindInstantiatedDecl(D, TemplateArgs);
1502    return cast_or_null<DeclContext>(ID);
1503  } else return DC;
1504}
1505
1506/// \brief Find the instantiation of the given declaration within the
1507/// current instantiation.
1508///
1509/// This routine is intended to be used when \p D is a declaration
1510/// referenced from within a template, that needs to mapped into the
1511/// corresponding declaration within an instantiation. For example,
1512/// given:
1513///
1514/// \code
1515/// template<typename T>
1516/// struct X {
1517///   enum Kind {
1518///     KnownValue = sizeof(T)
1519///   };
1520///
1521///   bool getKind() const { return KnownValue; }
1522/// };
1523///
1524/// template struct X<int>;
1525/// \endcode
1526///
1527/// In the instantiation of X<int>::getKind(), we need to map the
1528/// EnumConstantDecl for KnownValue (which refers to
1529/// X<T>::<Kind>::KnownValue) to its instantiation
1530/// (X<int>::<Kind>::KnownValue). InstantiateCurrentDeclRef() performs
1531/// this mapping from within the instantiation of X<int>.
1532NamedDecl *Sema::FindInstantiatedDecl(NamedDecl *D,
1533                          const MultiLevelTemplateArgumentList &TemplateArgs) {
1534  if (OverloadedFunctionDecl *Ovl = dyn_cast<OverloadedFunctionDecl>(D)) {
1535    // Transform all of the elements of the overloaded function set.
1536    OverloadedFunctionDecl *Result
1537      = OverloadedFunctionDecl::Create(Context, CurContext, Ovl->getDeclName());
1538
1539    for (OverloadedFunctionDecl::function_iterator F = Ovl->function_begin(),
1540                                                FEnd = Ovl->function_end();
1541         F != FEnd; ++F) {
1542      Result->addOverload(
1543        AnyFunctionDecl::getFromNamedDecl(FindInstantiatedDecl(*F,
1544                                                               TemplateArgs)));
1545    }
1546
1547    return Result;
1548  }
1549
1550  DeclContext *ParentDC = D->getDeclContext();
1551  if (isa<ParmVarDecl>(D) || ParentDC->isFunctionOrMethod()) {
1552    // D is a local of some kind. Look into the map of local
1553    // declarations to their instantiations.
1554    return cast<NamedDecl>(CurrentInstantiationScope->getInstantiationOf(D));
1555  }
1556
1557  if (CXXRecordDecl *Record = dyn_cast<CXXRecordDecl>(D)) {
1558    if (!Record->isDependentContext())
1559      return D;
1560
1561    // If the RecordDecl is actually the injected-class-name or a "templated"
1562    // declaration for a class template or class template partial
1563    // specialization, substitute into the injected-class-name of the
1564    // class template or partial specialization to find the new DeclContext.
1565    QualType T;
1566    ClassTemplateDecl *ClassTemplate = Record->getDescribedClassTemplate();
1567
1568    if (ClassTemplate) {
1569      T = ClassTemplate->getInjectedClassNameType(Context);
1570    } else if (ClassTemplatePartialSpecializationDecl *PartialSpec
1571                 = dyn_cast<ClassTemplatePartialSpecializationDecl>(Record)) {
1572      T = Context.getTypeDeclType(Record);
1573      ClassTemplate = PartialSpec->getSpecializedTemplate();
1574    }
1575
1576    if (!T.isNull()) {
1577      // Substitute into the injected-class-name to get the type corresponding
1578      // to the instantiation we want. This substitution should never fail,
1579      // since we know we can instantiate the injected-class-name or we wouldn't
1580      // have gotten to the injected-class-name!
1581      // FIXME: Can we use the CurrentInstantiationScope to avoid this extra
1582      // instantiation in the common case?
1583      T = SubstType(T, TemplateArgs, SourceLocation(), DeclarationName());
1584      assert(!T.isNull() && "Instantiation of injected-class-name cannot fail.");
1585
1586      if (!T->isDependentType()) {
1587        assert(T->isRecordType() && "Instantiation must produce a record type");
1588        return T->getAs<RecordType>()->getDecl();
1589      }
1590
1591      // We are performing "partial" template instantiation to create the
1592      // member declarations for the members of a class template
1593      // specialization. Therefore, D is actually referring to something in
1594      // the current instantiation. Look through the current context,
1595      // which contains actual instantiations, to find the instantiation of
1596      // the "current instantiation" that D refers to.
1597      for (DeclContext *DC = CurContext; !DC->isFileContext();
1598           DC = DC->getParent()) {
1599        if (ClassTemplateSpecializationDecl *Spec
1600              = dyn_cast<ClassTemplateSpecializationDecl>(DC))
1601          if (isInstantiationOf(ClassTemplate,
1602                                Spec->getSpecializedTemplate()))
1603            return Spec;
1604      }
1605
1606      assert(false &&
1607             "Unable to find declaration for the current instantiation");
1608      return Record;
1609    }
1610
1611    // Fall through to deal with other dependent record types (e.g.,
1612    // anonymous unions in class templates).
1613  }
1614
1615  if (!ParentDC->isDependentContext())
1616    return D;
1617
1618  ParentDC = FindInstantiatedContext(ParentDC, TemplateArgs);
1619  if (!ParentDC)
1620    return 0;
1621
1622  if (ParentDC != D->getDeclContext()) {
1623    // We performed some kind of instantiation in the parent context,
1624    // so now we need to look into the instantiated parent context to
1625    // find the instantiation of the declaration D.
1626    NamedDecl *Result = 0;
1627    if (D->getDeclName()) {
1628      DeclContext::lookup_result Found = ParentDC->lookup(D->getDeclName());
1629      Result = findInstantiationOf(Context, D, Found.first, Found.second);
1630    } else {
1631      // Since we don't have a name for the entity we're looking for,
1632      // our only option is to walk through all of the declarations to
1633      // find that name. This will occur in a few cases:
1634      //
1635      //   - anonymous struct/union within a template
1636      //   - unnamed class/struct/union/enum within a template
1637      //
1638      // FIXME: Find a better way to find these instantiations!
1639      Result = findInstantiationOf(Context, D,
1640                                   ParentDC->decls_begin(),
1641                                   ParentDC->decls_end());
1642    }
1643
1644    assert(Result && "Unable to find instantiation of declaration!");
1645    D = Result;
1646  }
1647
1648  return D;
1649}
1650
1651/// \brief Performs template instantiation for all implicit template
1652/// instantiations we have seen until this point.
1653void Sema::PerformPendingImplicitInstantiations() {
1654  while (!PendingImplicitInstantiations.empty()) {
1655    PendingImplicitInstantiation Inst = PendingImplicitInstantiations.front();
1656    PendingImplicitInstantiations.pop_front();
1657
1658    // Instantiate function definitions
1659    if (FunctionDecl *Function = dyn_cast<FunctionDecl>(Inst.first)) {
1660      PrettyStackTraceActionsDecl CrashInfo(DeclPtrTy::make(Function),
1661                                            Function->getLocation(), *this,
1662                                            Context.getSourceManager(),
1663                                           "instantiating function definition");
1664
1665      if (!Function->getBody())
1666        InstantiateFunctionDefinition(/*FIXME:*/Inst.second, Function, true);
1667      continue;
1668    }
1669
1670    // Instantiate static data member definitions.
1671    VarDecl *Var = cast<VarDecl>(Inst.first);
1672    assert(Var->isStaticDataMember() && "Not a static data member?");
1673
1674    PrettyStackTraceActionsDecl CrashInfo(DeclPtrTy::make(Var),
1675                                          Var->getLocation(), *this,
1676                                          Context.getSourceManager(),
1677                                          "instantiating static data member "
1678                                          "definition");
1679
1680    InstantiateStaticDataMemberDefinition(/*FIXME:*/Inst.second, Var, true);
1681  }
1682}
1683