ASTImporter.cpp revision 0e12b44081c6395a6d60a05a85a6012f7bb23b16 
1//===--- ASTImporter.cpp - Importing ASTs from other Contexts ---*- C++ -*-===//
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//
10//  This file defines the ASTImporter class which imports AST nodes from one
11//  context into another context.
12//
13//===----------------------------------------------------------------------===//
14#include "clang/AST/ASTImporter.h"
15
16#include "clang/AST/ASTContext.h"
17#include "clang/AST/ASTDiagnostic.h"
18#include "clang/AST/DeclCXX.h"
19#include "clang/AST/DeclObjC.h"
20#include "clang/AST/DeclVisitor.h"
21#include "clang/AST/StmtVisitor.h"
22#include "clang/AST/TypeLoc.h"
23#include "clang/AST/TypeVisitor.h"
24#include "clang/Basic/FileManager.h"
25#include "clang/Basic/SourceManager.h"
26#include "llvm/Support/MemoryBuffer.h"
27#include <deque>
28
29using namespace clang;
30
31namespace {
32  class ASTNodeImporter : public TypeVisitor<ASTNodeImporter, QualType>,
33                          public DeclVisitor<ASTNodeImporter, Decl *>,
34                          public StmtVisitor<ASTNodeImporter, Stmt *> {
35    ASTImporter &Importer;
36
37  public:
38    explicit ASTNodeImporter(ASTImporter &Importer) : Importer(Importer) { }
39
40    using TypeVisitor<ASTNodeImporter, QualType>::Visit;
41    using DeclVisitor<ASTNodeImporter, Decl *>::Visit;
42    using StmtVisitor<ASTNodeImporter, Stmt *>::Visit;
43
44    // Importing types
45    QualType VisitType(Type *T);
46    QualType VisitBuiltinType(BuiltinType *T);
47    QualType VisitComplexType(ComplexType *T);
48    QualType VisitPointerType(PointerType *T);
49    QualType VisitBlockPointerType(BlockPointerType *T);
50    QualType VisitLValueReferenceType(LValueReferenceType *T);
51    QualType VisitRValueReferenceType(RValueReferenceType *T);
52    QualType VisitMemberPointerType(MemberPointerType *T);
53    QualType VisitConstantArrayType(ConstantArrayType *T);
54    QualType VisitIncompleteArrayType(IncompleteArrayType *T);
55    QualType VisitVariableArrayType(VariableArrayType *T);
56    // FIXME: DependentSizedArrayType
57    // FIXME: DependentSizedExtVectorType
58    QualType VisitVectorType(VectorType *T);
59    QualType VisitExtVectorType(ExtVectorType *T);
60    QualType VisitFunctionNoProtoType(FunctionNoProtoType *T);
61    QualType VisitFunctionProtoType(FunctionProtoType *T);
62    // FIXME: UnresolvedUsingType
63    QualType VisitTypedefType(TypedefType *T);
64    QualType VisitTypeOfExprType(TypeOfExprType *T);
65    // FIXME: DependentTypeOfExprType
66    QualType VisitTypeOfType(TypeOfType *T);
67    QualType VisitDecltypeType(DecltypeType *T);
68    // FIXME: DependentDecltypeType
69    QualType VisitRecordType(RecordType *T);
70    QualType VisitEnumType(EnumType *T);
71    QualType VisitElaboratedType(ElaboratedType *T);
72    // FIXME: TemplateTypeParmType
73    // FIXME: SubstTemplateTypeParmType
74    // FIXME: TemplateSpecializationType
75    QualType VisitQualifiedNameType(QualifiedNameType *T);
76    // FIXME: TypenameType
77    QualType VisitObjCInterfaceType(ObjCInterfaceType *T);
78    QualType VisitObjCObjectPointerType(ObjCObjectPointerType *T);
79
80    // Importing declarations
81    bool ImportDeclParts(NamedDecl *D, DeclContext *&DC,
82                         DeclContext *&LexicalDC, DeclarationName &Name,
83                         SourceLocation &Loc);
84    bool IsStructuralMatch(RecordDecl *FromRecord, RecordDecl *ToRecord);
85    bool IsStructuralMatch(EnumDecl *FromEnum, EnumDecl *ToRecord);
86    Decl *VisitDecl(Decl *D);
87    Decl *VisitTypedefDecl(TypedefDecl *D);
88    Decl *VisitEnumDecl(EnumDecl *D);
89    Decl *VisitRecordDecl(RecordDecl *D);
90    Decl *VisitEnumConstantDecl(EnumConstantDecl *D);
91    Decl *VisitFunctionDecl(FunctionDecl *D);
92    Decl *VisitFieldDecl(FieldDecl *D);
93    Decl *VisitObjCIvarDecl(ObjCIvarDecl *D);
94    Decl *VisitVarDecl(VarDecl *D);
95    Decl *VisitImplicitParamDecl(ImplicitParamDecl *D);
96    Decl *VisitParmVarDecl(ParmVarDecl *D);
97    Decl *VisitObjCMethodDecl(ObjCMethodDecl *D);
98    Decl *VisitObjCCategoryDecl(ObjCCategoryDecl *D);
99    Decl *VisitObjCProtocolDecl(ObjCProtocolDecl *D);
100    Decl *VisitObjCInterfaceDecl(ObjCInterfaceDecl *D);
101    Decl *VisitObjCPropertyDecl(ObjCPropertyDecl *D);
102    Decl *VisitObjCForwardProtocolDecl(ObjCForwardProtocolDecl *D);
103    Decl *VisitObjCClassDecl(ObjCClassDecl *D);
104
105    // Importing statements
106    Stmt *VisitStmt(Stmt *S);
107
108    // Importing expressions
109    Expr *VisitExpr(Expr *E);
110    Expr *VisitDeclRefExpr(DeclRefExpr *E);
111    Expr *VisitIntegerLiteral(IntegerLiteral *E);
112    Expr *VisitCharacterLiteral(CharacterLiteral *E);
113    Expr *VisitParenExpr(ParenExpr *E);
114    Expr *VisitUnaryOperator(UnaryOperator *E);
115    Expr *VisitSizeOfAlignOfExpr(SizeOfAlignOfExpr *E);
116    Expr *VisitBinaryOperator(BinaryOperator *E);
117    Expr *VisitCompoundAssignOperator(CompoundAssignOperator *E);
118    Expr *VisitImplicitCastExpr(ImplicitCastExpr *E);
119    Expr *VisitCStyleCastExpr(CStyleCastExpr *E);
120  };
121}
122
123//----------------------------------------------------------------------------
124// Structural Equivalence
125//----------------------------------------------------------------------------
126
127namespace {
128  struct StructuralEquivalenceContext {
129    /// \brief AST contexts for which we are checking structural equivalence.
130    ASTContext &C1, &C2;
131
132    /// \brief Diagnostic object used to emit diagnostics.
133    Diagnostic &Diags;
134
135    /// \brief The set of "tentative" equivalences between two canonical
136    /// declarations, mapping from a declaration in the first context to the
137    /// declaration in the second context that we believe to be equivalent.
138    llvm::DenseMap<Decl *, Decl *> TentativeEquivalences;
139
140    /// \brief Queue of declarations in the first context whose equivalence
141    /// with a declaration in the second context still needs to be verified.
142    std::deque<Decl *> DeclsToCheck;
143
144    /// \brief Declaration (from, to) pairs that are known not to be equivalent
145    /// (which we have already complained about).
146    llvm::DenseSet<std::pair<Decl *, Decl *> > &NonEquivalentDecls;
147
148    /// \brief Whether we're being strict about the spelling of types when
149    /// unifying two types.
150    bool StrictTypeSpelling;
151
152    StructuralEquivalenceContext(ASTContext &C1, ASTContext &C2,
153                                 Diagnostic &Diags,
154               llvm::DenseSet<std::pair<Decl *, Decl *> > &NonEquivalentDecls,
155                                 bool StrictTypeSpelling = false)
156      : C1(C1), C2(C2), Diags(Diags), NonEquivalentDecls(NonEquivalentDecls),
157        StrictTypeSpelling(StrictTypeSpelling) { }
158
159    /// \brief Determine whether the two declarations are structurally
160    /// equivalent.
161    bool IsStructurallyEquivalent(Decl *D1, Decl *D2);
162
163    /// \brief Determine whether the two types are structurally equivalent.
164    bool IsStructurallyEquivalent(QualType T1, QualType T2);
165
166  private:
167    /// \brief Finish checking all of the structural equivalences.
168    ///
169    /// \returns true if an error occurred, false otherwise.
170    bool Finish();
171
172  public:
173    DiagnosticBuilder Diag1(SourceLocation Loc, unsigned DiagID) {
174      return Diags.Report(FullSourceLoc(Loc, C1.getSourceManager()), DiagID);
175    }
176
177    DiagnosticBuilder Diag2(SourceLocation Loc, unsigned DiagID) {
178      return Diags.Report(FullSourceLoc(Loc, C2.getSourceManager()), DiagID);
179    }
180  };
181}
182
183static bool IsStructurallyEquivalent(StructuralEquivalenceContext &Context,
184                                     QualType T1, QualType T2);
185static bool IsStructurallyEquivalent(StructuralEquivalenceContext &Context,
186                                     Decl *D1, Decl *D2);
187
188/// \brief Determine if two APInts have the same value, after zero-extending
189/// one of them (if needed!) to ensure that the bit-widths match.
190static bool IsSameValue(const llvm::APInt &I1, const llvm::APInt &I2) {
191  if (I1.getBitWidth() == I2.getBitWidth())
192    return I1 == I2;
193
194  if (I1.getBitWidth() > I2.getBitWidth())
195    return I1 == llvm::APInt(I2).zext(I1.getBitWidth());
196
197  return llvm::APInt(I1).zext(I2.getBitWidth()) == I2;
198}
199
200/// \brief Determine if two APSInts have the same value, zero- or sign-extending
201/// as needed.
202static bool IsSameValue(const llvm::APSInt &I1, const llvm::APSInt &I2) {
203  if (I1.getBitWidth() == I2.getBitWidth() && I1.isSigned() == I2.isSigned())
204    return I1 == I2;
205
206  // Check for a bit-width mismatch.
207  if (I1.getBitWidth() > I2.getBitWidth())
208    return IsSameValue(I1, llvm::APSInt(I2).extend(I1.getBitWidth()));
209  else if (I2.getBitWidth() > I1.getBitWidth())
210    return IsSameValue(llvm::APSInt(I1).extend(I2.getBitWidth()), I2);
211
212  // We have a signedness mismatch. Turn the signed value into an unsigned
213  // value.
214  if (I1.isSigned()) {
215    if (I1.isNegative())
216      return false;
217
218    return llvm::APSInt(I1, true) == I2;
219  }
220
221  if (I2.isNegative())
222    return false;
223
224  return I1 == llvm::APSInt(I2, true);
225}
226
227/// \brief Determine structural equivalence of two expressions.
228static bool IsStructurallyEquivalent(StructuralEquivalenceContext &Context,
229                                     Expr *E1, Expr *E2) {
230  if (!E1 || !E2)
231    return E1 == E2;
232
233  // FIXME: Actually perform a structural comparison!
234  return true;
235}
236
237/// \brief Determine whether two identifiers are equivalent.
238static bool IsStructurallyEquivalent(const IdentifierInfo *Name1,
239                                     const IdentifierInfo *Name2) {
240  if (!Name1 || !Name2)
241    return Name1 == Name2;
242
243  return Name1->getName() == Name2->getName();
244}
245
246/// \brief Determine whether two nested-name-specifiers are equivalent.
247static bool IsStructurallyEquivalent(StructuralEquivalenceContext &Context,
248                                     NestedNameSpecifier *NNS1,
249                                     NestedNameSpecifier *NNS2) {
250  // FIXME: Implement!
251  return true;
252}
253
254/// \brief Determine whether two template arguments are equivalent.
255static bool IsStructurallyEquivalent(StructuralEquivalenceContext &Context,
256                                     const TemplateArgument &Arg1,
257                                     const TemplateArgument &Arg2) {
258  // FIXME: Implement!
259  return true;
260}
261
262/// \brief Determine structural equivalence for the common part of array
263/// types.
264static bool IsArrayStructurallyEquivalent(StructuralEquivalenceContext &Context,
265                                          const ArrayType *Array1,
266                                          const ArrayType *Array2) {
267  if (!IsStructurallyEquivalent(Context,
268                                Array1->getElementType(),
269                                Array2->getElementType()))
270    return false;
271  if (Array1->getSizeModifier() != Array2->getSizeModifier())
272    return false;
273  if (Array1->getIndexTypeQualifiers() != Array2->getIndexTypeQualifiers())
274    return false;
275
276  return true;
277}
278
279/// \brief Determine structural equivalence of two types.
280static bool IsStructurallyEquivalent(StructuralEquivalenceContext &Context,
281                                     QualType T1, QualType T2) {
282  if (T1.isNull() || T2.isNull())
283    return T1.isNull() && T2.isNull();
284
285  if (!Context.StrictTypeSpelling) {
286    // We aren't being strict about token-to-token equivalence of types,
287    // so map down to the canonical type.
288    T1 = Context.C1.getCanonicalType(T1);
289    T2 = Context.C2.getCanonicalType(T2);
290  }
291
292  if (T1.getQualifiers() != T2.getQualifiers())
293    return false;
294
295  Type::TypeClass TC = T1->getTypeClass();
296
297  if (T1->getTypeClass() != T2->getTypeClass()) {
298    // Compare function types with prototypes vs. without prototypes as if
299    // both did not have prototypes.
300    if (T1->getTypeClass() == Type::FunctionProto &&
301        T2->getTypeClass() == Type::FunctionNoProto)
302      TC = Type::FunctionNoProto;
303    else if (T1->getTypeClass() == Type::FunctionNoProto &&
304             T2->getTypeClass() == Type::FunctionProto)
305      TC = Type::FunctionNoProto;
306    else
307      return false;
308  }
309
310  switch (TC) {
311  case Type::Builtin:
312    // FIXME: Deal with Char_S/Char_U.
313    if (cast<BuiltinType>(T1)->getKind() != cast<BuiltinType>(T2)->getKind())
314      return false;
315    break;
316
317  case Type::Complex:
318    if (!IsStructurallyEquivalent(Context,
319                                  cast<ComplexType>(T1)->getElementType(),
320                                  cast<ComplexType>(T2)->getElementType()))
321      return false;
322    break;
323
324  case Type::Pointer:
325    if (!IsStructurallyEquivalent(Context,
326                                  cast<PointerType>(T1)->getPointeeType(),
327                                  cast<PointerType>(T2)->getPointeeType()))
328      return false;
329    break;
330
331  case Type::BlockPointer:
332    if (!IsStructurallyEquivalent(Context,
333                                  cast<BlockPointerType>(T1)->getPointeeType(),
334                                  cast<BlockPointerType>(T2)->getPointeeType()))
335      return false;
336    break;
337
338  case Type::LValueReference:
339  case Type::RValueReference: {
340    const ReferenceType *Ref1 = cast<ReferenceType>(T1);
341    const ReferenceType *Ref2 = cast<ReferenceType>(T2);
342    if (Ref1->isSpelledAsLValue() != Ref2->isSpelledAsLValue())
343      return false;
344    if (Ref1->isInnerRef() != Ref2->isInnerRef())
345      return false;
346    if (!IsStructurallyEquivalent(Context,
347                                  Ref1->getPointeeTypeAsWritten(),
348                                  Ref2->getPointeeTypeAsWritten()))
349      return false;
350    break;
351  }
352
353  case Type::MemberPointer: {
354    const MemberPointerType *MemPtr1 = cast<MemberPointerType>(T1);
355    const MemberPointerType *MemPtr2 = cast<MemberPointerType>(T2);
356    if (!IsStructurallyEquivalent(Context,
357                                  MemPtr1->getPointeeType(),
358                                  MemPtr2->getPointeeType()))
359      return false;
360    if (!IsStructurallyEquivalent(Context,
361                                  QualType(MemPtr1->getClass(), 0),
362                                  QualType(MemPtr2->getClass(), 0)))
363      return false;
364    break;
365  }
366
367  case Type::ConstantArray: {
368    const ConstantArrayType *Array1 = cast<ConstantArrayType>(T1);
369    const ConstantArrayType *Array2 = cast<ConstantArrayType>(T2);
370    if (!IsSameValue(Array1->getSize(), Array2->getSize()))
371      return false;
372
373    if (!IsArrayStructurallyEquivalent(Context, Array1, Array2))
374      return false;
375    break;
376  }
377
378  case Type::IncompleteArray:
379    if (!IsArrayStructurallyEquivalent(Context,
380                                       cast<ArrayType>(T1),
381                                       cast<ArrayType>(T2)))
382      return false;
383    break;
384
385  case Type::VariableArray: {
386    const VariableArrayType *Array1 = cast<VariableArrayType>(T1);
387    const VariableArrayType *Array2 = cast<VariableArrayType>(T2);
388    if (!IsStructurallyEquivalent(Context,
389                                  Array1->getSizeExpr(), Array2->getSizeExpr()))
390      return false;
391
392    if (!IsArrayStructurallyEquivalent(Context, Array1, Array2))
393      return false;
394
395    break;
396  }
397
398  case Type::DependentSizedArray: {
399    const DependentSizedArrayType *Array1 = cast<DependentSizedArrayType>(T1);
400    const DependentSizedArrayType *Array2 = cast<DependentSizedArrayType>(T2);
401    if (!IsStructurallyEquivalent(Context,
402                                  Array1->getSizeExpr(), Array2->getSizeExpr()))
403      return false;
404
405    if (!IsArrayStructurallyEquivalent(Context, Array1, Array2))
406      return false;
407
408    break;
409  }
410
411  case Type::DependentSizedExtVector: {
412    const DependentSizedExtVectorType *Vec1
413      = cast<DependentSizedExtVectorType>(T1);
414    const DependentSizedExtVectorType *Vec2
415      = cast<DependentSizedExtVectorType>(T2);
416    if (!IsStructurallyEquivalent(Context,
417                                  Vec1->getSizeExpr(), Vec2->getSizeExpr()))
418      return false;
419    if (!IsStructurallyEquivalent(Context,
420                                  Vec1->getElementType(),
421                                  Vec2->getElementType()))
422      return false;
423    break;
424  }
425
426  case Type::Vector:
427  case Type::ExtVector: {
428    const VectorType *Vec1 = cast<VectorType>(T1);
429    const VectorType *Vec2 = cast<VectorType>(T2);
430    if (!IsStructurallyEquivalent(Context,
431                                  Vec1->getElementType(),
432                                  Vec2->getElementType()))
433      return false;
434    if (Vec1->getNumElements() != Vec2->getNumElements())
435      return false;
436    if (Vec1->isAltiVec() != Vec2->isAltiVec())
437      return false;
438    if (Vec1->isPixel() != Vec2->isPixel())
439      return false;
440    break;
441  }
442
443  case Type::FunctionProto: {
444    const FunctionProtoType *Proto1 = cast<FunctionProtoType>(T1);
445    const FunctionProtoType *Proto2 = cast<FunctionProtoType>(T2);
446    if (Proto1->getNumArgs() != Proto2->getNumArgs())
447      return false;
448    for (unsigned I = 0, N = Proto1->getNumArgs(); I != N; ++I) {
449      if (!IsStructurallyEquivalent(Context,
450                                    Proto1->getArgType(I),
451                                    Proto2->getArgType(I)))
452        return false;
453    }
454    if (Proto1->isVariadic() != Proto2->isVariadic())
455      return false;
456    if (Proto1->hasExceptionSpec() != Proto2->hasExceptionSpec())
457      return false;
458    if (Proto1->hasAnyExceptionSpec() != Proto2->hasAnyExceptionSpec())
459      return false;
460    if (Proto1->getNumExceptions() != Proto2->getNumExceptions())
461      return false;
462    for (unsigned I = 0, N = Proto1->getNumExceptions(); I != N; ++I) {
463      if (!IsStructurallyEquivalent(Context,
464                                    Proto1->getExceptionType(I),
465                                    Proto2->getExceptionType(I)))
466        return false;
467    }
468    if (Proto1->getTypeQuals() != Proto2->getTypeQuals())
469      return false;
470
471    // Fall through to check the bits common with FunctionNoProtoType.
472  }
473
474  case Type::FunctionNoProto: {
475    const FunctionType *Function1 = cast<FunctionType>(T1);
476    const FunctionType *Function2 = cast<FunctionType>(T2);
477    if (!IsStructurallyEquivalent(Context,
478                                  Function1->getResultType(),
479                                  Function2->getResultType()))
480      return false;
481    if (Function1->getNoReturnAttr() != Function2->getNoReturnAttr())
482      return false;
483    if (Function1->getCallConv() != Function2->getCallConv())
484      return false;
485    break;
486  }
487
488  case Type::UnresolvedUsing:
489    if (!IsStructurallyEquivalent(Context,
490                                  cast<UnresolvedUsingType>(T1)->getDecl(),
491                                  cast<UnresolvedUsingType>(T2)->getDecl()))
492      return false;
493
494    break;
495
496  case Type::Typedef:
497    if (!IsStructurallyEquivalent(Context,
498                                  cast<TypedefType>(T1)->getDecl(),
499                                  cast<TypedefType>(T2)->getDecl()))
500      return false;
501    break;
502
503  case Type::TypeOfExpr:
504    if (!IsStructurallyEquivalent(Context,
505                                cast<TypeOfExprType>(T1)->getUnderlyingExpr(),
506                                cast<TypeOfExprType>(T2)->getUnderlyingExpr()))
507      return false;
508    break;
509
510  case Type::TypeOf:
511    if (!IsStructurallyEquivalent(Context,
512                                  cast<TypeOfType>(T1)->getUnderlyingType(),
513                                  cast<TypeOfType>(T2)->getUnderlyingType()))
514      return false;
515    break;
516
517  case Type::Decltype:
518    if (!IsStructurallyEquivalent(Context,
519                                  cast<DecltypeType>(T1)->getUnderlyingExpr(),
520                                  cast<DecltypeType>(T2)->getUnderlyingExpr()))
521      return false;
522    break;
523
524  case Type::Record:
525  case Type::Enum:
526    if (!IsStructurallyEquivalent(Context,
527                                  cast<TagType>(T1)->getDecl(),
528                                  cast<TagType>(T2)->getDecl()))
529      return false;
530    break;
531
532  case Type::Elaborated: {
533    const ElaboratedType *Elab1 = cast<ElaboratedType>(T1);
534    const ElaboratedType *Elab2 = cast<ElaboratedType>(T2);
535    if (Elab1->getTagKind() != Elab2->getTagKind())
536      return false;
537    if (!IsStructurallyEquivalent(Context,
538                                  Elab1->getUnderlyingType(),
539                                  Elab2->getUnderlyingType()))
540      return false;
541    break;
542  }
543
544  case Type::TemplateTypeParm: {
545    const TemplateTypeParmType *Parm1 = cast<TemplateTypeParmType>(T1);
546    const TemplateTypeParmType *Parm2 = cast<TemplateTypeParmType>(T2);
547    if (Parm1->getDepth() != Parm2->getDepth())
548      return false;
549    if (Parm1->getIndex() != Parm2->getIndex())
550      return false;
551    if (Parm1->isParameterPack() != Parm2->isParameterPack())
552      return false;
553
554    // Names of template type parameters are never significant.
555    break;
556  }
557
558  case Type::SubstTemplateTypeParm: {
559    const SubstTemplateTypeParmType *Subst1
560      = cast<SubstTemplateTypeParmType>(T1);
561    const SubstTemplateTypeParmType *Subst2
562      = cast<SubstTemplateTypeParmType>(T2);
563    if (!IsStructurallyEquivalent(Context,
564                                  QualType(Subst1->getReplacedParameter(), 0),
565                                  QualType(Subst2->getReplacedParameter(), 0)))
566      return false;
567    if (!IsStructurallyEquivalent(Context,
568                                  Subst1->getReplacementType(),
569                                  Subst2->getReplacementType()))
570      return false;
571    break;
572  }
573
574  case Type::TemplateSpecialization: {
575    const TemplateSpecializationType *Spec1
576      = cast<TemplateSpecializationType>(T1);
577    const TemplateSpecializationType *Spec2
578      = cast<TemplateSpecializationType>(T2);
579    if (!IsStructurallyEquivalent(Context,
580                                  Spec1->getTemplateName(),
581                                  Spec2->getTemplateName()))
582      return false;
583    if (Spec1->getNumArgs() != Spec2->getNumArgs())
584      return false;
585    for (unsigned I = 0, N = Spec1->getNumArgs(); I != N; ++I) {
586      if (!IsStructurallyEquivalent(Context,
587                                    Spec1->getArg(I), Spec2->getArg(I)))
588        return false;
589    }
590    break;
591  }
592
593  case Type::QualifiedName: {
594    const QualifiedNameType *Qual1 = cast<QualifiedNameType>(T1);
595    const QualifiedNameType *Qual2 = cast<QualifiedNameType>(T2);
596    if (!IsStructurallyEquivalent(Context,
597                                  Qual1->getQualifier(),
598                                  Qual2->getQualifier()))
599      return false;
600    if (!IsStructurallyEquivalent(Context,
601                                  Qual1->getNamedType(),
602                                  Qual2->getNamedType()))
603      return false;
604    break;
605  }
606
607  case Type::Typename: {
608    const TypenameType *Typename1 = cast<TypenameType>(T1);
609    const TypenameType *Typename2 = cast<TypenameType>(T2);
610    if (!IsStructurallyEquivalent(Context,
611                                  Typename1->getQualifier(),
612                                  Typename2->getQualifier()))
613      return false;
614    if (!IsStructurallyEquivalent(Typename1->getIdentifier(),
615                                  Typename2->getIdentifier()))
616      return false;
617    if (!IsStructurallyEquivalent(Context,
618                                  QualType(Typename1->getTemplateId(), 0),
619                                  QualType(Typename2->getTemplateId(), 0)))
620      return false;
621
622    break;
623  }
624
625  case Type::ObjCInterface: {
626    const ObjCInterfaceType *Iface1 = cast<ObjCInterfaceType>(T1);
627    const ObjCInterfaceType *Iface2 = cast<ObjCInterfaceType>(T2);
628    if (!IsStructurallyEquivalent(Context,
629                                  Iface1->getDecl(), Iface2->getDecl()))
630      return false;
631    if (Iface1->getNumProtocols() != Iface2->getNumProtocols())
632      return false;
633    for (unsigned I = 0, N = Iface1->getNumProtocols(); I != N; ++I) {
634      if (!IsStructurallyEquivalent(Context,
635                                    Iface1->getProtocol(I),
636                                    Iface2->getProtocol(I)))
637        return false;
638    }
639    break;
640  }
641
642  case Type::ObjCObjectPointer: {
643    const ObjCObjectPointerType *Ptr1 = cast<ObjCObjectPointerType>(T1);
644    const ObjCObjectPointerType *Ptr2 = cast<ObjCObjectPointerType>(T2);
645    if (!IsStructurallyEquivalent(Context,
646                                  Ptr1->getPointeeType(),
647                                  Ptr2->getPointeeType()))
648      return false;
649    if (Ptr1->getNumProtocols() != Ptr2->getNumProtocols())
650      return false;
651    for (unsigned I = 0, N = Ptr1->getNumProtocols(); I != N; ++I) {
652      if (!IsStructurallyEquivalent(Context,
653                                    Ptr1->getProtocol(I),
654                                    Ptr2->getProtocol(I)))
655        return false;
656    }
657    break;
658  }
659
660  } // end switch
661
662  return true;
663}
664
665/// \brief Determine structural equivalence of two records.
666static bool IsStructurallyEquivalent(StructuralEquivalenceContext &Context,
667                                     RecordDecl *D1, RecordDecl *D2) {
668  if (D1->isUnion() != D2->isUnion()) {
669    Context.Diag2(D2->getLocation(), diag::warn_odr_tag_type_inconsistent)
670      << Context.C2.getTypeDeclType(D2);
671    Context.Diag1(D1->getLocation(), diag::note_odr_tag_kind_here)
672      << D1->getDeclName() << (unsigned)D1->getTagKind();
673    return false;
674  }
675
676  // Compare the definitions of these two records. If either or both are
677  // incomplete, we assume that they are equivalent.
678  D1 = D1->getDefinition();
679  D2 = D2->getDefinition();
680  if (!D1 || !D2)
681    return true;
682
683  if (CXXRecordDecl *D1CXX = dyn_cast<CXXRecordDecl>(D1)) {
684    if (CXXRecordDecl *D2CXX = dyn_cast<CXXRecordDecl>(D2)) {
685      if (D1CXX->getNumBases() != D2CXX->getNumBases()) {
686        Context.Diag2(D2->getLocation(), diag::warn_odr_tag_type_inconsistent)
687        << Context.C2.getTypeDeclType(D2);
688        Context.Diag2(D2->getLocation(), diag::note_odr_number_of_bases)
689        << D2CXX->getNumBases();
690        Context.Diag1(D1->getLocation(), diag::note_odr_number_of_bases)
691        << D1CXX->getNumBases();
692        return false;
693      }
694
695      // Check the base classes.
696      for (CXXRecordDecl::base_class_iterator Base1 = D1CXX->bases_begin(),
697                                           BaseEnd1 = D1CXX->bases_end(),
698                                                Base2 = D2CXX->bases_begin();
699           Base1 != BaseEnd1;
700           ++Base1, ++Base2) {
701        if (!IsStructurallyEquivalent(Context,
702                                      Base1->getType(), Base2->getType())) {
703          Context.Diag2(D2->getLocation(), diag::warn_odr_tag_type_inconsistent)
704            << Context.C2.getTypeDeclType(D2);
705          Context.Diag2(Base2->getSourceRange().getBegin(), diag::note_odr_base)
706            << Base2->getType()
707            << Base2->getSourceRange();
708          Context.Diag1(Base1->getSourceRange().getBegin(), diag::note_odr_base)
709            << Base1->getType()
710            << Base1->getSourceRange();
711          return false;
712        }
713
714        // Check virtual vs. non-virtual inheritance mismatch.
715        if (Base1->isVirtual() != Base2->isVirtual()) {
716          Context.Diag2(D2->getLocation(), diag::warn_odr_tag_type_inconsistent)
717            << Context.C2.getTypeDeclType(D2);
718          Context.Diag2(Base2->getSourceRange().getBegin(),
719                        diag::note_odr_virtual_base)
720            << Base2->isVirtual() << Base2->getSourceRange();
721          Context.Diag1(Base1->getSourceRange().getBegin(), diag::note_odr_base)
722            << Base1->isVirtual()
723            << Base1->getSourceRange();
724          return false;
725        }
726      }
727    } else if (D1CXX->getNumBases() > 0) {
728      Context.Diag2(D2->getLocation(), diag::warn_odr_tag_type_inconsistent)
729        << Context.C2.getTypeDeclType(D2);
730      const CXXBaseSpecifier *Base1 = D1CXX->bases_begin();
731      Context.Diag1(Base1->getSourceRange().getBegin(), diag::note_odr_base)
732        << Base1->getType()
733        << Base1->getSourceRange();
734      Context.Diag2(D2->getLocation(), diag::note_odr_missing_base);
735      return false;
736    }
737  }
738
739  // Check the fields for consistency.
740  CXXRecordDecl::field_iterator Field2 = D2->field_begin(),
741                             Field2End = D2->field_end();
742  for (CXXRecordDecl::field_iterator Field1 = D1->field_begin(),
743                                  Field1End = D1->field_end();
744       Field1 != Field1End;
745       ++Field1, ++Field2) {
746    if (Field2 == Field2End) {
747      Context.Diag2(D2->getLocation(), diag::warn_odr_tag_type_inconsistent)
748        << Context.C2.getTypeDeclType(D2);
749      Context.Diag1(Field1->getLocation(), diag::note_odr_field)
750        << Field1->getDeclName() << Field1->getType();
751      Context.Diag2(D2->getLocation(), diag::note_odr_missing_field);
752      return false;
753    }
754
755    if (!IsStructurallyEquivalent(Context,
756                                  Field1->getType(), Field2->getType())) {
757      Context.Diag2(D2->getLocation(), diag::warn_odr_tag_type_inconsistent)
758        << Context.C2.getTypeDeclType(D2);
759      Context.Diag2(Field2->getLocation(), diag::note_odr_field)
760        << Field2->getDeclName() << Field2->getType();
761      Context.Diag1(Field1->getLocation(), diag::note_odr_field)
762        << Field1->getDeclName() << Field1->getType();
763      return false;
764    }
765
766    if (Field1->isBitField() != Field2->isBitField()) {
767      Context.Diag2(D2->getLocation(), diag::warn_odr_tag_type_inconsistent)
768        << Context.C2.getTypeDeclType(D2);
769      if (Field1->isBitField()) {
770        llvm::APSInt Bits;
771        Field1->getBitWidth()->isIntegerConstantExpr(Bits, Context.C1);
772        Context.Diag1(Field1->getLocation(), diag::note_odr_bit_field)
773          << Field1->getDeclName() << Field1->getType()
774          << Bits.toString(10, false);
775        Context.Diag2(Field2->getLocation(), diag::note_odr_not_bit_field)
776          << Field2->getDeclName();
777      } else {
778        llvm::APSInt Bits;
779        Field2->getBitWidth()->isIntegerConstantExpr(Bits, Context.C2);
780        Context.Diag2(Field2->getLocation(), diag::note_odr_bit_field)
781          << Field2->getDeclName() << Field2->getType()
782          << Bits.toString(10, false);
783        Context.Diag1(Field1->getLocation(),
784                          diag::note_odr_not_bit_field)
785        << Field1->getDeclName();
786      }
787      return false;
788    }
789
790    if (Field1->isBitField()) {
791      // Make sure that the bit-fields are the same length.
792      llvm::APSInt Bits1, Bits2;
793      if (!Field1->getBitWidth()->isIntegerConstantExpr(Bits1, Context.C1))
794        return false;
795      if (!Field2->getBitWidth()->isIntegerConstantExpr(Bits2, Context.C2))
796        return false;
797
798      if (!IsSameValue(Bits1, Bits2)) {
799        Context.Diag2(D2->getLocation(), diag::warn_odr_tag_type_inconsistent)
800          << Context.C2.getTypeDeclType(D2);
801        Context.Diag2(Field2->getLocation(), diag::note_odr_bit_field)
802          << Field2->getDeclName() << Field2->getType()
803          << Bits2.toString(10, false);
804        Context.Diag1(Field1->getLocation(), diag::note_odr_bit_field)
805          << Field1->getDeclName() << Field1->getType()
806          << Bits1.toString(10, false);
807        return false;
808      }
809    }
810  }
811
812  if (Field2 != Field2End) {
813    Context.Diag2(D2->getLocation(), diag::warn_odr_tag_type_inconsistent)
814      << Context.C2.getTypeDeclType(D2);
815    Context.Diag2(Field2->getLocation(), diag::note_odr_field)
816      << Field2->getDeclName() << Field2->getType();
817    Context.Diag1(D1->getLocation(), diag::note_odr_missing_field);
818    return false;
819  }
820
821  return true;
822}
823
824/// \brief Determine structural equivalence of two enums.
825static bool IsStructurallyEquivalent(StructuralEquivalenceContext &Context,
826                                     EnumDecl *D1, EnumDecl *D2) {
827  EnumDecl::enumerator_iterator EC2 = D2->enumerator_begin(),
828                             EC2End = D2->enumerator_end();
829  for (EnumDecl::enumerator_iterator EC1 = D1->enumerator_begin(),
830                                  EC1End = D1->enumerator_end();
831       EC1 != EC1End; ++EC1, ++EC2) {
832    if (EC2 == EC2End) {
833      Context.Diag2(D2->getLocation(), diag::warn_odr_tag_type_inconsistent)
834        << Context.C2.getTypeDeclType(D2);
835      Context.Diag1(EC1->getLocation(), diag::note_odr_enumerator)
836        << EC1->getDeclName()
837        << EC1->getInitVal().toString(10);
838      Context.Diag2(D2->getLocation(), diag::note_odr_missing_enumerator);
839      return false;
840    }
841
842    llvm::APSInt Val1 = EC1->getInitVal();
843    llvm::APSInt Val2 = EC2->getInitVal();
844    if (!IsSameValue(Val1, Val2) ||
845        !IsStructurallyEquivalent(EC1->getIdentifier(), EC2->getIdentifier())) {
846      Context.Diag2(D2->getLocation(), diag::warn_odr_tag_type_inconsistent)
847        << Context.C2.getTypeDeclType(D2);
848      Context.Diag2(EC2->getLocation(), diag::note_odr_enumerator)
849        << EC2->getDeclName()
850        << EC2->getInitVal().toString(10);
851      Context.Diag1(EC1->getLocation(), diag::note_odr_enumerator)
852        << EC1->getDeclName()
853        << EC1->getInitVal().toString(10);
854      return false;
855    }
856  }
857
858  if (EC2 != EC2End) {
859    Context.Diag2(D2->getLocation(), diag::warn_odr_tag_type_inconsistent)
860      << Context.C2.getTypeDeclType(D2);
861    Context.Diag2(EC2->getLocation(), diag::note_odr_enumerator)
862      << EC2->getDeclName()
863      << EC2->getInitVal().toString(10);
864    Context.Diag1(D1->getLocation(), diag::note_odr_missing_enumerator);
865    return false;
866  }
867
868  return true;
869}
870
871/// \brief Determine structural equivalence of two declarations.
872static bool IsStructurallyEquivalent(StructuralEquivalenceContext &Context,
873                                     Decl *D1, Decl *D2) {
874  // FIXME: Check for known structural equivalences via a callback of some sort.
875
876  // Check whether we already know that these two declarations are not
877  // structurally equivalent.
878  if (Context.NonEquivalentDecls.count(std::make_pair(D1->getCanonicalDecl(),
879                                                      D2->getCanonicalDecl())))
880    return false;
881
882  // Determine whether we've already produced a tentative equivalence for D1.
883  Decl *&EquivToD1 = Context.TentativeEquivalences[D1->getCanonicalDecl()];
884  if (EquivToD1)
885    return EquivToD1 == D2->getCanonicalDecl();
886
887  // Produce a tentative equivalence D1 <-> D2, which will be checked later.
888  EquivToD1 = D2->getCanonicalDecl();
889  Context.DeclsToCheck.push_back(D1->getCanonicalDecl());
890  return true;
891}
892
893bool StructuralEquivalenceContext::IsStructurallyEquivalent(Decl *D1,
894                                                            Decl *D2) {
895  if (!::IsStructurallyEquivalent(*this, D1, D2))
896    return false;
897
898  return !Finish();
899}
900
901bool StructuralEquivalenceContext::IsStructurallyEquivalent(QualType T1,
902                                                            QualType T2) {
903  if (!::IsStructurallyEquivalent(*this, T1, T2))
904    return false;
905
906  return !Finish();
907}
908
909bool StructuralEquivalenceContext::Finish() {
910  while (!DeclsToCheck.empty()) {
911    // Check the next declaration.
912    Decl *D1 = DeclsToCheck.front();
913    DeclsToCheck.pop_front();
914
915    Decl *D2 = TentativeEquivalences[D1];
916    assert(D2 && "Unrecorded tentative equivalence?");
917
918    bool Equivalent = true;
919
920    // FIXME: Switch on all declaration kinds. For now, we're just going to
921    // check the obvious ones.
922    if (RecordDecl *Record1 = dyn_cast<RecordDecl>(D1)) {
923      if (RecordDecl *Record2 = dyn_cast<RecordDecl>(D2)) {
924        // Check for equivalent structure names.
925        IdentifierInfo *Name1 = Record1->getIdentifier();
926        if (!Name1 && Record1->getTypedefForAnonDecl())
927          Name1 = Record1->getTypedefForAnonDecl()->getIdentifier();
928        IdentifierInfo *Name2 = Record2->getIdentifier();
929        if (!Name2 && Record2->getTypedefForAnonDecl())
930          Name2 = Record2->getTypedefForAnonDecl()->getIdentifier();
931        if (!::IsStructurallyEquivalent(Name1, Name2) ||
932            !::IsStructurallyEquivalent(*this, Record1, Record2))
933          Equivalent = false;
934      } else {
935        // Record/non-record mismatch.
936        Equivalent = false;
937      }
938    } else if (EnumDecl *Enum1 = dyn_cast<EnumDecl>(D1)) {
939      if (EnumDecl *Enum2 = dyn_cast<EnumDecl>(D2)) {
940        // Check for equivalent enum names.
941        IdentifierInfo *Name1 = Enum1->getIdentifier();
942        if (!Name1 && Enum1->getTypedefForAnonDecl())
943          Name1 = Enum1->getTypedefForAnonDecl()->getIdentifier();
944        IdentifierInfo *Name2 = Enum2->getIdentifier();
945        if (!Name2 && Enum2->getTypedefForAnonDecl())
946          Name2 = Enum2->getTypedefForAnonDecl()->getIdentifier();
947        if (!::IsStructurallyEquivalent(Name1, Name2) ||
948            !::IsStructurallyEquivalent(*this, Enum1, Enum2))
949          Equivalent = false;
950      } else {
951        // Enum/non-enum mismatch
952        Equivalent = false;
953      }
954    } else if (TypedefDecl *Typedef1 = dyn_cast<TypedefDecl>(D1)) {
955      if (TypedefDecl *Typedef2 = dyn_cast<TypedefDecl>(D2)) {
956        if (!::IsStructurallyEquivalent(Typedef1->getIdentifier(),
957                                        Typedef2->getIdentifier()) ||
958            !::IsStructurallyEquivalent(*this,
959                                        Typedef1->getUnderlyingType(),
960                                        Typedef2->getUnderlyingType()))
961          Equivalent = false;
962      } else {
963        // Typedef/non-typedef mismatch.
964        Equivalent = false;
965      }
966    }
967
968    if (!Equivalent) {
969      // Note that these two declarations are not equivalent (and we already
970      // know about it).
971      NonEquivalentDecls.insert(std::make_pair(D1->getCanonicalDecl(),
972                                               D2->getCanonicalDecl()));
973      return true;
974    }
975    // FIXME: Check other declaration kinds!
976  }
977
978  return false;
979}
980
981//----------------------------------------------------------------------------
982// Import Types
983//----------------------------------------------------------------------------
984
985QualType ASTNodeImporter::VisitType(Type *T) {
986  Importer.FromDiag(SourceLocation(), diag::err_unsupported_ast_node)
987    << T->getTypeClassName();
988  return QualType();
989}
990
991QualType ASTNodeImporter::VisitBuiltinType(BuiltinType *T) {
992  switch (T->getKind()) {
993  case BuiltinType::Void: return Importer.getToContext().VoidTy;
994  case BuiltinType::Bool: return Importer.getToContext().BoolTy;
995
996  case BuiltinType::Char_U:
997    // The context we're importing from has an unsigned 'char'. If we're
998    // importing into a context with a signed 'char', translate to
999    // 'unsigned char' instead.
1000    if (Importer.getToContext().getLangOptions().CharIsSigned)
1001      return Importer.getToContext().UnsignedCharTy;
1002
1003    return Importer.getToContext().CharTy;
1004
1005  case BuiltinType::UChar: return Importer.getToContext().UnsignedCharTy;
1006
1007  case BuiltinType::Char16:
1008    // FIXME: Make sure that the "to" context supports C++!
1009    return Importer.getToContext().Char16Ty;
1010
1011  case BuiltinType::Char32:
1012    // FIXME: Make sure that the "to" context supports C++!
1013    return Importer.getToContext().Char32Ty;
1014
1015  case BuiltinType::UShort: return Importer.getToContext().UnsignedShortTy;
1016  case BuiltinType::UInt: return Importer.getToContext().UnsignedIntTy;
1017  case BuiltinType::ULong: return Importer.getToContext().UnsignedLongTy;
1018  case BuiltinType::ULongLong:
1019    return Importer.getToContext().UnsignedLongLongTy;
1020  case BuiltinType::UInt128: return Importer.getToContext().UnsignedInt128Ty;
1021
1022  case BuiltinType::Char_S:
1023    // The context we're importing from has an unsigned 'char'. If we're
1024    // importing into a context with a signed 'char', translate to
1025    // 'unsigned char' instead.
1026    if (!Importer.getToContext().getLangOptions().CharIsSigned)
1027      return Importer.getToContext().SignedCharTy;
1028
1029    return Importer.getToContext().CharTy;
1030
1031  case BuiltinType::SChar: return Importer.getToContext().SignedCharTy;
1032  case BuiltinType::WChar:
1033    // FIXME: If not in C++, shall we translate to the C equivalent of
1034    // wchar_t?
1035    return Importer.getToContext().WCharTy;
1036
1037  case BuiltinType::Short : return Importer.getToContext().ShortTy;
1038  case BuiltinType::Int : return Importer.getToContext().IntTy;
1039  case BuiltinType::Long : return Importer.getToContext().LongTy;
1040  case BuiltinType::LongLong : return Importer.getToContext().LongLongTy;
1041  case BuiltinType::Int128 : return Importer.getToContext().Int128Ty;
1042  case BuiltinType::Float: return Importer.getToContext().FloatTy;
1043  case BuiltinType::Double: return Importer.getToContext().DoubleTy;
1044  case BuiltinType::LongDouble: return Importer.getToContext().LongDoubleTy;
1045
1046  case BuiltinType::NullPtr:
1047    // FIXME: Make sure that the "to" context supports C++0x!
1048    return Importer.getToContext().NullPtrTy;
1049
1050  case BuiltinType::Overload: return Importer.getToContext().OverloadTy;
1051  case BuiltinType::Dependent: return Importer.getToContext().DependentTy;
1052  case BuiltinType::UndeducedAuto:
1053    // FIXME: Make sure that the "to" context supports C++0x!
1054    return Importer.getToContext().UndeducedAutoTy;
1055
1056  case BuiltinType::ObjCId:
1057    // FIXME: Make sure that the "to" context supports Objective-C!
1058    return Importer.getToContext().ObjCBuiltinIdTy;
1059
1060  case BuiltinType::ObjCClass:
1061    return Importer.getToContext().ObjCBuiltinClassTy;
1062
1063  case BuiltinType::ObjCSel:
1064    return Importer.getToContext().ObjCBuiltinSelTy;
1065  }
1066
1067  return QualType();
1068}
1069
1070QualType ASTNodeImporter::VisitComplexType(ComplexType *T) {
1071  QualType ToElementType = Importer.Import(T->getElementType());
1072  if (ToElementType.isNull())
1073    return QualType();
1074
1075  return Importer.getToContext().getComplexType(ToElementType);
1076}
1077
1078QualType ASTNodeImporter::VisitPointerType(PointerType *T) {
1079  QualType ToPointeeType = Importer.Import(T->getPointeeType());
1080  if (ToPointeeType.isNull())
1081    return QualType();
1082
1083  return Importer.getToContext().getPointerType(ToPointeeType);
1084}
1085
1086QualType ASTNodeImporter::VisitBlockPointerType(BlockPointerType *T) {
1087  // FIXME: Check for blocks support in "to" context.
1088  QualType ToPointeeType = Importer.Import(T->getPointeeType());
1089  if (ToPointeeType.isNull())
1090    return QualType();
1091
1092  return Importer.getToContext().getBlockPointerType(ToPointeeType);
1093}
1094
1095QualType ASTNodeImporter::VisitLValueReferenceType(LValueReferenceType *T) {
1096  // FIXME: Check for C++ support in "to" context.
1097  QualType ToPointeeType = Importer.Import(T->getPointeeTypeAsWritten());
1098  if (ToPointeeType.isNull())
1099    return QualType();
1100
1101  return Importer.getToContext().getLValueReferenceType(ToPointeeType);
1102}
1103
1104QualType ASTNodeImporter::VisitRValueReferenceType(RValueReferenceType *T) {
1105  // FIXME: Check for C++0x support in "to" context.
1106  QualType ToPointeeType = Importer.Import(T->getPointeeTypeAsWritten());
1107  if (ToPointeeType.isNull())
1108    return QualType();
1109
1110  return Importer.getToContext().getRValueReferenceType(ToPointeeType);
1111}
1112
1113QualType ASTNodeImporter::VisitMemberPointerType(MemberPointerType *T) {
1114  // FIXME: Check for C++ support in "to" context.
1115  QualType ToPointeeType = Importer.Import(T->getPointeeType());
1116  if (ToPointeeType.isNull())
1117    return QualType();
1118
1119  QualType ClassType = Importer.Import(QualType(T->getClass(), 0));
1120  return Importer.getToContext().getMemberPointerType(ToPointeeType,
1121                                                      ClassType.getTypePtr());
1122}
1123
1124QualType ASTNodeImporter::VisitConstantArrayType(ConstantArrayType *T) {
1125  QualType ToElementType = Importer.Import(T->getElementType());
1126  if (ToElementType.isNull())
1127    return QualType();
1128
1129  return Importer.getToContext().getConstantArrayType(ToElementType,
1130                                                      T->getSize(),
1131                                                      T->getSizeModifier(),
1132                                               T->getIndexTypeCVRQualifiers());
1133}
1134
1135QualType ASTNodeImporter::VisitIncompleteArrayType(IncompleteArrayType *T) {
1136  QualType ToElementType = Importer.Import(T->getElementType());
1137  if (ToElementType.isNull())
1138    return QualType();
1139
1140  return Importer.getToContext().getIncompleteArrayType(ToElementType,
1141                                                        T->getSizeModifier(),
1142                                                T->getIndexTypeCVRQualifiers());
1143}
1144
1145QualType ASTNodeImporter::VisitVariableArrayType(VariableArrayType *T) {
1146  QualType ToElementType = Importer.Import(T->getElementType());
1147  if (ToElementType.isNull())
1148    return QualType();
1149
1150  Expr *Size = Importer.Import(T->getSizeExpr());
1151  if (!Size)
1152    return QualType();
1153
1154  SourceRange Brackets = Importer.Import(T->getBracketsRange());
1155  return Importer.getToContext().getVariableArrayType(ToElementType, Size,
1156                                                      T->getSizeModifier(),
1157                                                T->getIndexTypeCVRQualifiers(),
1158                                                      Brackets);
1159}
1160
1161QualType ASTNodeImporter::VisitVectorType(VectorType *T) {
1162  QualType ToElementType = Importer.Import(T->getElementType());
1163  if (ToElementType.isNull())
1164    return QualType();
1165
1166  return Importer.getToContext().getVectorType(ToElementType,
1167                                               T->getNumElements(),
1168                                               T->isAltiVec(),
1169                                               T->isPixel());
1170}
1171
1172QualType ASTNodeImporter::VisitExtVectorType(ExtVectorType *T) {
1173  QualType ToElementType = Importer.Import(T->getElementType());
1174  if (ToElementType.isNull())
1175    return QualType();
1176
1177  return Importer.getToContext().getExtVectorType(ToElementType,
1178                                                  T->getNumElements());
1179}
1180
1181QualType ASTNodeImporter::VisitFunctionNoProtoType(FunctionNoProtoType *T) {
1182  // FIXME: What happens if we're importing a function without a prototype
1183  // into C++? Should we make it variadic?
1184  QualType ToResultType = Importer.Import(T->getResultType());
1185  if (ToResultType.isNull())
1186    return QualType();
1187
1188  return Importer.getToContext().getFunctionNoProtoType(ToResultType,
1189                                                        T->getNoReturnAttr(),
1190                                                        T->getCallConv());
1191}
1192
1193QualType ASTNodeImporter::VisitFunctionProtoType(FunctionProtoType *T) {
1194  QualType ToResultType = Importer.Import(T->getResultType());
1195  if (ToResultType.isNull())
1196    return QualType();
1197
1198  // Import argument types
1199  llvm::SmallVector<QualType, 4> ArgTypes;
1200  for (FunctionProtoType::arg_type_iterator A = T->arg_type_begin(),
1201                                         AEnd = T->arg_type_end();
1202       A != AEnd; ++A) {
1203    QualType ArgType = Importer.Import(*A);
1204    if (ArgType.isNull())
1205      return QualType();
1206    ArgTypes.push_back(ArgType);
1207  }
1208
1209  // Import exception types
1210  llvm::SmallVector<QualType, 4> ExceptionTypes;
1211  for (FunctionProtoType::exception_iterator E = T->exception_begin(),
1212                                          EEnd = T->exception_end();
1213       E != EEnd; ++E) {
1214    QualType ExceptionType = Importer.Import(*E);
1215    if (ExceptionType.isNull())
1216      return QualType();
1217    ExceptionTypes.push_back(ExceptionType);
1218  }
1219
1220  return Importer.getToContext().getFunctionType(ToResultType, ArgTypes.data(),
1221                                                 ArgTypes.size(),
1222                                                 T->isVariadic(),
1223                                                 T->getTypeQuals(),
1224                                                 T->hasExceptionSpec(),
1225                                                 T->hasAnyExceptionSpec(),
1226                                                 ExceptionTypes.size(),
1227                                                 ExceptionTypes.data(),
1228                                                 T->getNoReturnAttr(),
1229                                                 T->getCallConv());
1230}
1231
1232QualType ASTNodeImporter::VisitTypedefType(TypedefType *T) {
1233  TypedefDecl *ToDecl
1234                 = dyn_cast_or_null<TypedefDecl>(Importer.Import(T->getDecl()));
1235  if (!ToDecl)
1236    return QualType();
1237
1238  return Importer.getToContext().getTypeDeclType(ToDecl);
1239}
1240
1241QualType ASTNodeImporter::VisitTypeOfExprType(TypeOfExprType *T) {
1242  Expr *ToExpr = Importer.Import(T->getUnderlyingExpr());
1243  if (!ToExpr)
1244    return QualType();
1245
1246  return Importer.getToContext().getTypeOfExprType(ToExpr);
1247}
1248
1249QualType ASTNodeImporter::VisitTypeOfType(TypeOfType *T) {
1250  QualType ToUnderlyingType = Importer.Import(T->getUnderlyingType());
1251  if (ToUnderlyingType.isNull())
1252    return QualType();
1253
1254  return Importer.getToContext().getTypeOfType(ToUnderlyingType);
1255}
1256
1257QualType ASTNodeImporter::VisitDecltypeType(DecltypeType *T) {
1258  Expr *ToExpr = Importer.Import(T->getUnderlyingExpr());
1259  if (!ToExpr)
1260    return QualType();
1261
1262  return Importer.getToContext().getDecltypeType(ToExpr);
1263}
1264
1265QualType ASTNodeImporter::VisitRecordType(RecordType *T) {
1266  RecordDecl *ToDecl
1267    = dyn_cast_or_null<RecordDecl>(Importer.Import(T->getDecl()));
1268  if (!ToDecl)
1269    return QualType();
1270
1271  return Importer.getToContext().getTagDeclType(ToDecl);
1272}
1273
1274QualType ASTNodeImporter::VisitEnumType(EnumType *T) {
1275  EnumDecl *ToDecl
1276    = dyn_cast_or_null<EnumDecl>(Importer.Import(T->getDecl()));
1277  if (!ToDecl)
1278    return QualType();
1279
1280  return Importer.getToContext().getTagDeclType(ToDecl);
1281}
1282
1283QualType ASTNodeImporter::VisitElaboratedType(ElaboratedType *T) {
1284  QualType ToUnderlyingType = Importer.Import(T->getUnderlyingType());
1285  if (ToUnderlyingType.isNull())
1286    return QualType();
1287
1288  return Importer.getToContext().getElaboratedType(ToUnderlyingType,
1289                                                   T->getTagKind());
1290}
1291
1292QualType ASTNodeImporter::VisitQualifiedNameType(QualifiedNameType *T) {
1293  NestedNameSpecifier *ToQualifier = Importer.Import(T->getQualifier());
1294  if (!ToQualifier)
1295    return QualType();
1296
1297  QualType ToNamedType = Importer.Import(T->getNamedType());
1298  if (ToNamedType.isNull())
1299    return QualType();
1300
1301  return Importer.getToContext().getQualifiedNameType(ToQualifier, ToNamedType);
1302}
1303
1304QualType ASTNodeImporter::VisitObjCInterfaceType(ObjCInterfaceType *T) {
1305  ObjCInterfaceDecl *Class
1306    = dyn_cast_or_null<ObjCInterfaceDecl>(Importer.Import(T->getDecl()));
1307  if (!Class)
1308    return QualType();
1309
1310  llvm::SmallVector<ObjCProtocolDecl *, 4> Protocols;
1311  for (ObjCInterfaceType::qual_iterator P = T->qual_begin(),
1312                                     PEnd = T->qual_end();
1313       P != PEnd; ++P) {
1314    ObjCProtocolDecl *Protocol
1315      = dyn_cast_or_null<ObjCProtocolDecl>(Importer.Import(*P));
1316    if (!Protocol)
1317      return QualType();
1318    Protocols.push_back(Protocol);
1319  }
1320
1321  return Importer.getToContext().getObjCInterfaceType(Class,
1322                                                      Protocols.data(),
1323                                                      Protocols.size());
1324}
1325
1326QualType ASTNodeImporter::VisitObjCObjectPointerType(ObjCObjectPointerType *T) {
1327  QualType ToPointeeType = Importer.Import(T->getPointeeType());
1328  if (ToPointeeType.isNull())
1329    return QualType();
1330
1331  llvm::SmallVector<ObjCProtocolDecl *, 4> Protocols;
1332  for (ObjCObjectPointerType::qual_iterator P = T->qual_begin(),
1333                                         PEnd = T->qual_end();
1334       P != PEnd; ++P) {
1335    ObjCProtocolDecl *Protocol
1336      = dyn_cast_or_null<ObjCProtocolDecl>(Importer.Import(*P));
1337    if (!Protocol)
1338      return QualType();
1339    Protocols.push_back(Protocol);
1340  }
1341
1342  return Importer.getToContext().getObjCObjectPointerType(ToPointeeType,
1343                                                          Protocols.data(),
1344                                                          Protocols.size());
1345}
1346
1347//----------------------------------------------------------------------------
1348// Import Declarations
1349//----------------------------------------------------------------------------
1350bool ASTNodeImporter::ImportDeclParts(NamedDecl *D, DeclContext *&DC,
1351                                      DeclContext *&LexicalDC,
1352                                      DeclarationName &Name,
1353                                      SourceLocation &Loc) {
1354  // Import the context of this declaration.
1355  DC = Importer.ImportContext(D->getDeclContext());
1356  if (!DC)
1357    return true;
1358
1359  LexicalDC = DC;
1360  if (D->getDeclContext() != D->getLexicalDeclContext()) {
1361    LexicalDC = Importer.ImportContext(D->getLexicalDeclContext());
1362    if (!LexicalDC)
1363      return true;
1364  }
1365
1366  // Import the name of this declaration.
1367  Name = Importer.Import(D->getDeclName());
1368  if (D->getDeclName() && !Name)
1369    return true;
1370
1371  // Import the location of this declaration.
1372  Loc = Importer.Import(D->getLocation());
1373  return false;
1374}
1375
1376bool ASTNodeImporter::IsStructuralMatch(RecordDecl *FromRecord,
1377                                        RecordDecl *ToRecord) {
1378  StructuralEquivalenceContext Ctx(Importer.getFromContext(),
1379                                   Importer.getToContext(),
1380                                   Importer.getDiags(),
1381                                   Importer.getNonEquivalentDecls());
1382  return Ctx.IsStructurallyEquivalent(FromRecord, ToRecord);
1383}
1384
1385bool ASTNodeImporter::IsStructuralMatch(EnumDecl *FromEnum, EnumDecl *ToEnum) {
1386  StructuralEquivalenceContext Ctx(Importer.getFromContext(),
1387                                   Importer.getToContext(),
1388                                   Importer.getDiags(),
1389                                   Importer.getNonEquivalentDecls());
1390  return Ctx.IsStructurallyEquivalent(FromEnum, ToEnum);
1391}
1392
1393Decl *ASTNodeImporter::VisitDecl(Decl *D) {
1394  Importer.FromDiag(D->getLocation(), diag::err_unsupported_ast_node)
1395    << D->getDeclKindName();
1396  return 0;
1397}
1398
1399Decl *ASTNodeImporter::VisitTypedefDecl(TypedefDecl *D) {
1400  // Import the major distinguishing characteristics of this typedef.
1401  DeclContext *DC, *LexicalDC;
1402  DeclarationName Name;
1403  SourceLocation Loc;
1404  if (ImportDeclParts(D, DC, LexicalDC, Name, Loc))
1405    return 0;
1406
1407  // If this typedef is not in block scope, determine whether we've
1408  // seen a typedef with the same name (that we can merge with) or any
1409  // other entity by that name (which name lookup could conflict with).
1410  if (!DC->isFunctionOrMethod()) {
1411    llvm::SmallVector<NamedDecl *, 4> ConflictingDecls;
1412    unsigned IDNS = Decl::IDNS_Ordinary;
1413    for (DeclContext::lookup_result Lookup = DC->lookup(Name);
1414         Lookup.first != Lookup.second;
1415         ++Lookup.first) {
1416      if (!(*Lookup.first)->isInIdentifierNamespace(IDNS))
1417        continue;
1418      if (TypedefDecl *FoundTypedef = dyn_cast<TypedefDecl>(*Lookup.first)) {
1419        if (Importer.IsStructurallyEquivalent(D->getUnderlyingType(),
1420                                            FoundTypedef->getUnderlyingType()))
1421          return Importer.Imported(D, FoundTypedef);
1422      }
1423
1424      ConflictingDecls.push_back(*Lookup.first);
1425    }
1426
1427    if (!ConflictingDecls.empty()) {
1428      Name = Importer.HandleNameConflict(Name, DC, IDNS,
1429                                         ConflictingDecls.data(),
1430                                         ConflictingDecls.size());
1431      if (!Name)
1432        return 0;
1433    }
1434  }
1435
1436  // Import the underlying type of this typedef;
1437  QualType T = Importer.Import(D->getUnderlyingType());
1438  if (T.isNull())
1439    return 0;
1440
1441  // Create the new typedef node.
1442  TypeSourceInfo *TInfo = Importer.Import(D->getTypeSourceInfo());
1443  TypedefDecl *ToTypedef = TypedefDecl::Create(Importer.getToContext(), DC,
1444                                               Loc, Name.getAsIdentifierInfo(),
1445                                               TInfo);
1446  ToTypedef->setLexicalDeclContext(LexicalDC);
1447  Importer.Imported(D, ToTypedef);
1448  LexicalDC->addDecl(ToTypedef);
1449
1450  return ToTypedef;
1451}
1452
1453Decl *ASTNodeImporter::VisitEnumDecl(EnumDecl *D) {
1454  // Import the major distinguishing characteristics of this enum.
1455  DeclContext *DC, *LexicalDC;
1456  DeclarationName Name;
1457  SourceLocation Loc;
1458  if (ImportDeclParts(D, DC, LexicalDC, Name, Loc))
1459    return 0;
1460
1461  // Figure out what enum name we're looking for.
1462  unsigned IDNS = Decl::IDNS_Tag;
1463  DeclarationName SearchName = Name;
1464  if (!SearchName && D->getTypedefForAnonDecl()) {
1465    SearchName = Importer.Import(D->getTypedefForAnonDecl()->getDeclName());
1466    IDNS = Decl::IDNS_Ordinary;
1467  } else if (Importer.getToContext().getLangOptions().CPlusPlus)
1468    IDNS |= Decl::IDNS_Ordinary;
1469
1470  // We may already have an enum of the same name; try to find and match it.
1471  if (!DC->isFunctionOrMethod() && SearchName) {
1472    llvm::SmallVector<NamedDecl *, 4> ConflictingDecls;
1473    for (DeclContext::lookup_result Lookup = DC->lookup(Name);
1474         Lookup.first != Lookup.second;
1475         ++Lookup.first) {
1476      if (!(*Lookup.first)->isInIdentifierNamespace(IDNS))
1477        continue;
1478
1479      Decl *Found = *Lookup.first;
1480      if (TypedefDecl *Typedef = dyn_cast<TypedefDecl>(Found)) {
1481        if (const TagType *Tag = Typedef->getUnderlyingType()->getAs<TagType>())
1482          Found = Tag->getDecl();
1483      }
1484
1485      if (EnumDecl *FoundEnum = dyn_cast<EnumDecl>(Found)) {
1486        if (IsStructuralMatch(D, FoundEnum))
1487          return Importer.Imported(D, FoundEnum);
1488      }
1489
1490      ConflictingDecls.push_back(*Lookup.first);
1491    }
1492
1493    if (!ConflictingDecls.empty()) {
1494      Name = Importer.HandleNameConflict(Name, DC, IDNS,
1495                                         ConflictingDecls.data(),
1496                                         ConflictingDecls.size());
1497    }
1498  }
1499
1500  // Create the enum declaration.
1501  EnumDecl *D2 = EnumDecl::Create(Importer.getToContext(), DC, Loc,
1502                                      Name.getAsIdentifierInfo(),
1503                                      Importer.Import(D->getTagKeywordLoc()),
1504                                      0);
1505  D2->setLexicalDeclContext(LexicalDC);
1506  Importer.Imported(D, D2);
1507  LexicalDC->addDecl(D2);
1508
1509  // Import the integer type.
1510  QualType ToIntegerType = Importer.Import(D->getIntegerType());
1511  if (ToIntegerType.isNull())
1512    return 0;
1513  D2->setIntegerType(ToIntegerType);
1514
1515  // Import the definition
1516  if (D->isDefinition()) {
1517    QualType T = Importer.Import(Importer.getFromContext().getTypeDeclType(D));
1518    if (T.isNull())
1519      return 0;
1520
1521    QualType ToPromotionType = Importer.Import(D->getPromotionType());
1522    if (ToPromotionType.isNull())
1523      return 0;
1524
1525    D2->startDefinition();
1526    for (DeclContext::decl_iterator FromMem = D->decls_begin(),
1527         FromMemEnd = D->decls_end();
1528         FromMem != FromMemEnd;
1529         ++FromMem)
1530      Importer.Import(*FromMem);
1531
1532    D2->completeDefinition(T, ToPromotionType);
1533  }
1534
1535  return D2;
1536}
1537
1538Decl *ASTNodeImporter::VisitRecordDecl(RecordDecl *D) {
1539  // If this record has a definition in the translation unit we're coming from,
1540  // but this particular declaration is not that definition, import the
1541  // definition and map to that.
1542  TagDecl *Definition = D->getDefinition();
1543  if (Definition && Definition != D) {
1544    Decl *ImportedDef = Importer.Import(Definition);
1545    if (!ImportedDef)
1546      return 0;
1547
1548    return Importer.Imported(D, ImportedDef);
1549  }
1550
1551  // Import the major distinguishing characteristics of this record.
1552  DeclContext *DC, *LexicalDC;
1553  DeclarationName Name;
1554  SourceLocation Loc;
1555  if (ImportDeclParts(D, DC, LexicalDC, Name, Loc))
1556    return 0;
1557
1558  // Figure out what structure name we're looking for.
1559  unsigned IDNS = Decl::IDNS_Tag;
1560  DeclarationName SearchName = Name;
1561  if (!SearchName && D->getTypedefForAnonDecl()) {
1562    SearchName = Importer.Import(D->getTypedefForAnonDecl()->getDeclName());
1563    IDNS = Decl::IDNS_Ordinary;
1564  } else if (Importer.getToContext().getLangOptions().CPlusPlus)
1565    IDNS |= Decl::IDNS_Ordinary;
1566
1567  // We may already have a record of the same name; try to find and match it.
1568  RecordDecl *AdoptDecl = 0;
1569  if (!DC->isFunctionOrMethod() && SearchName) {
1570    llvm::SmallVector<NamedDecl *, 4> ConflictingDecls;
1571    for (DeclContext::lookup_result Lookup = DC->lookup(Name);
1572         Lookup.first != Lookup.second;
1573         ++Lookup.first) {
1574      if (!(*Lookup.first)->isInIdentifierNamespace(IDNS))
1575        continue;
1576
1577      Decl *Found = *Lookup.first;
1578      if (TypedefDecl *Typedef = dyn_cast<TypedefDecl>(Found)) {
1579        if (const TagType *Tag = Typedef->getUnderlyingType()->getAs<TagType>())
1580          Found = Tag->getDecl();
1581      }
1582
1583      if (RecordDecl *FoundRecord = dyn_cast<RecordDecl>(Found)) {
1584        if (RecordDecl *FoundDef = FoundRecord->getDefinition()) {
1585          if (!D->isDefinition() || IsStructuralMatch(D, FoundDef)) {
1586            // The record types structurally match, or the "from" translation
1587            // unit only had a forward declaration anyway; call it the same
1588            // function.
1589            // FIXME: For C++, we should also merge methods here.
1590            return Importer.Imported(D, FoundDef);
1591          }
1592        } else {
1593          // We have a forward declaration of this type, so adopt that forward
1594          // declaration rather than building a new one.
1595          AdoptDecl = FoundRecord;
1596          continue;
1597        }
1598      }
1599
1600      ConflictingDecls.push_back(*Lookup.first);
1601    }
1602
1603    if (!ConflictingDecls.empty()) {
1604      Name = Importer.HandleNameConflict(Name, DC, IDNS,
1605                                         ConflictingDecls.data(),
1606                                         ConflictingDecls.size());
1607    }
1608  }
1609
1610  // Create the record declaration.
1611  RecordDecl *D2 = AdoptDecl;
1612  if (!D2) {
1613    if (CXXRecordDecl *D1CXX = dyn_cast<CXXRecordDecl>(D)) {
1614      CXXRecordDecl *D2CXX = CXXRecordDecl::Create(Importer.getToContext(),
1615                                                   D->getTagKind(),
1616                                                   DC, Loc,
1617                                                   Name.getAsIdentifierInfo(),
1618                                        Importer.Import(D->getTagKeywordLoc()));
1619      D2 = D2CXX;
1620
1621      if (D->isDefinition()) {
1622        // Add base classes.
1623        llvm::SmallVector<CXXBaseSpecifier *, 4> Bases;
1624        for (CXXRecordDecl::base_class_iterator
1625                  Base1 = D1CXX->bases_begin(),
1626               FromBaseEnd = D1CXX->bases_end();
1627             Base1 != FromBaseEnd;
1628             ++Base1) {
1629          QualType T = Importer.Import(Base1->getType());
1630          if (T.isNull())
1631            return 0;
1632
1633          Bases.push_back(
1634            new (Importer.getToContext())
1635                  CXXBaseSpecifier(Importer.Import(Base1->getSourceRange()),
1636                                   Base1->isVirtual(),
1637                                   Base1->isBaseOfClass(),
1638                                   Base1->getAccessSpecifierAsWritten(),
1639                                   T));
1640        }
1641        if (!Bases.empty())
1642          D2CXX->setBases(Bases.data(), Bases.size());
1643      }
1644    } else {
1645      D2 = RecordDecl::Create(Importer.getToContext(), D->getTagKind(),
1646                                    DC, Loc,
1647                                    Name.getAsIdentifierInfo(),
1648                                    Importer.Import(D->getTagKeywordLoc()));
1649    }
1650    D2->setLexicalDeclContext(LexicalDC);
1651    LexicalDC->addDecl(D2);
1652  }
1653
1654  Importer.Imported(D, D2);
1655
1656  if (D->isDefinition()) {
1657    D2->startDefinition();
1658    for (DeclContext::decl_iterator FromMem = D->decls_begin(),
1659                                 FromMemEnd = D->decls_end();
1660         FromMem != FromMemEnd;
1661         ++FromMem)
1662      Importer.Import(*FromMem);
1663
1664    D2->completeDefinition();
1665  }
1666
1667  return D2;
1668}
1669
1670Decl *ASTNodeImporter::VisitEnumConstantDecl(EnumConstantDecl *D) {
1671  // Import the major distinguishing characteristics of this enumerator.
1672  DeclContext *DC, *LexicalDC;
1673  DeclarationName Name;
1674  SourceLocation Loc;
1675  if (ImportDeclParts(D, DC, LexicalDC, Name, Loc))
1676    return 0;
1677
1678  QualType T = Importer.Import(D->getType());
1679  if (T.isNull())
1680    return 0;
1681
1682  // Determine whether there are any other declarations with the same name and
1683  // in the same context.
1684  if (!LexicalDC->isFunctionOrMethod()) {
1685    llvm::SmallVector<NamedDecl *, 4> ConflictingDecls;
1686    unsigned IDNS = Decl::IDNS_Ordinary;
1687    for (DeclContext::lookup_result Lookup = DC->lookup(Name);
1688         Lookup.first != Lookup.second;
1689         ++Lookup.first) {
1690      if (!(*Lookup.first)->isInIdentifierNamespace(IDNS))
1691        continue;
1692
1693      ConflictingDecls.push_back(*Lookup.first);
1694    }
1695
1696    if (!ConflictingDecls.empty()) {
1697      Name = Importer.HandleNameConflict(Name, DC, IDNS,
1698                                         ConflictingDecls.data(),
1699                                         ConflictingDecls.size());
1700      if (!Name)
1701        return 0;
1702    }
1703  }
1704
1705  Expr *Init = Importer.Import(D->getInitExpr());
1706  if (D->getInitExpr() && !Init)
1707    return 0;
1708
1709  EnumConstantDecl *ToEnumerator
1710    = EnumConstantDecl::Create(Importer.getToContext(), cast<EnumDecl>(DC), Loc,
1711                               Name.getAsIdentifierInfo(), T,
1712                               Init, D->getInitVal());
1713  ToEnumerator->setLexicalDeclContext(LexicalDC);
1714  Importer.Imported(D, ToEnumerator);
1715  LexicalDC->addDecl(ToEnumerator);
1716  return ToEnumerator;
1717}
1718
1719Decl *ASTNodeImporter::VisitFunctionDecl(FunctionDecl *D) {
1720  // Import the major distinguishing characteristics of this function.
1721  DeclContext *DC, *LexicalDC;
1722  DeclarationName Name;
1723  SourceLocation Loc;
1724  if (ImportDeclParts(D, DC, LexicalDC, Name, Loc))
1725    return 0;
1726
1727  // Try to find a function in our own ("to") context with the same name, same
1728  // type, and in the same context as the function we're importing.
1729  if (!LexicalDC->isFunctionOrMethod()) {
1730    llvm::SmallVector<NamedDecl *, 4> ConflictingDecls;
1731    unsigned IDNS = Decl::IDNS_Ordinary;
1732    for (DeclContext::lookup_result Lookup = DC->lookup(Name);
1733         Lookup.first != Lookup.second;
1734         ++Lookup.first) {
1735      if (!(*Lookup.first)->isInIdentifierNamespace(IDNS))
1736        continue;
1737
1738      if (FunctionDecl *FoundFunction = dyn_cast<FunctionDecl>(*Lookup.first)) {
1739        if (isExternalLinkage(FoundFunction->getLinkage()) &&
1740            isExternalLinkage(D->getLinkage())) {
1741          if (Importer.IsStructurallyEquivalent(D->getType(),
1742                                                FoundFunction->getType())) {
1743            // FIXME: Actually try to merge the body and other attributes.
1744            return Importer.Imported(D, FoundFunction);
1745          }
1746
1747          // FIXME: Check for overloading more carefully, e.g., by boosting
1748          // Sema::IsOverload out to the AST library.
1749
1750          // Function overloading is okay in C++.
1751          if (Importer.getToContext().getLangOptions().CPlusPlus)
1752            continue;
1753
1754          // Complain about inconsistent function types.
1755          Importer.ToDiag(Loc, diag::err_odr_function_type_inconsistent)
1756            << Name << D->getType() << FoundFunction->getType();
1757          Importer.ToDiag(FoundFunction->getLocation(),
1758                          diag::note_odr_value_here)
1759            << FoundFunction->getType();
1760        }
1761      }
1762
1763      ConflictingDecls.push_back(*Lookup.first);
1764    }
1765
1766    if (!ConflictingDecls.empty()) {
1767      Name = Importer.HandleNameConflict(Name, DC, IDNS,
1768                                         ConflictingDecls.data(),
1769                                         ConflictingDecls.size());
1770      if (!Name)
1771        return 0;
1772    }
1773  }
1774
1775  // Import the type.
1776  QualType T = Importer.Import(D->getType());
1777  if (T.isNull())
1778    return 0;
1779
1780  // Import the function parameters.
1781  llvm::SmallVector<ParmVarDecl *, 8> Parameters;
1782  for (FunctionDecl::param_iterator P = D->param_begin(), PEnd = D->param_end();
1783       P != PEnd; ++P) {
1784    ParmVarDecl *ToP = cast_or_null<ParmVarDecl>(Importer.Import(*P));
1785    if (!ToP)
1786      return 0;
1787
1788    Parameters.push_back(ToP);
1789  }
1790
1791  // Create the imported function.
1792  TypeSourceInfo *TInfo = Importer.Import(D->getTypeSourceInfo());
1793  FunctionDecl *ToFunction
1794    = FunctionDecl::Create(Importer.getToContext(), DC, Loc,
1795                           Name, T, TInfo, D->getStorageClass(),
1796                           D->isInlineSpecified(),
1797                           D->hasWrittenPrototype());
1798  ToFunction->setLexicalDeclContext(LexicalDC);
1799  Importer.Imported(D, ToFunction);
1800  LexicalDC->addDecl(ToFunction);
1801
1802  // Set the parameters.
1803  for (unsigned I = 0, N = Parameters.size(); I != N; ++I) {
1804    Parameters[I]->setOwningFunction(ToFunction);
1805    ToFunction->addDecl(Parameters[I]);
1806  }
1807  ToFunction->setParams(Parameters.data(), Parameters.size());
1808
1809  // FIXME: Other bits to merge?
1810
1811  return ToFunction;
1812}
1813
1814Decl *ASTNodeImporter::VisitFieldDecl(FieldDecl *D) {
1815  // Import the major distinguishing characteristics of a variable.
1816  DeclContext *DC, *LexicalDC;
1817  DeclarationName Name;
1818  SourceLocation Loc;
1819  if (ImportDeclParts(D, DC, LexicalDC, Name, Loc))
1820    return 0;
1821
1822  // Import the type.
1823  QualType T = Importer.Import(D->getType());
1824  if (T.isNull())
1825    return 0;
1826
1827  TypeSourceInfo *TInfo = Importer.Import(D->getTypeSourceInfo());
1828  Expr *BitWidth = Importer.Import(D->getBitWidth());
1829  if (!BitWidth && D->getBitWidth())
1830    return 0;
1831
1832  FieldDecl *ToField = FieldDecl::Create(Importer.getToContext(), DC,
1833                                         Loc, Name.getAsIdentifierInfo(),
1834                                         T, TInfo, BitWidth, D->isMutable());
1835  ToField->setLexicalDeclContext(LexicalDC);
1836  Importer.Imported(D, ToField);
1837  LexicalDC->addDecl(ToField);
1838  return ToField;
1839}
1840
1841Decl *ASTNodeImporter::VisitObjCIvarDecl(ObjCIvarDecl *D) {
1842  // Import the major distinguishing characteristics of an ivar.
1843  DeclContext *DC, *LexicalDC;
1844  DeclarationName Name;
1845  SourceLocation Loc;
1846  if (ImportDeclParts(D, DC, LexicalDC, Name, Loc))
1847    return 0;
1848
1849  // Determine whether we've already imported this ivar
1850  for (DeclContext::lookup_result Lookup = DC->lookup(Name);
1851       Lookup.first != Lookup.second;
1852       ++Lookup.first) {
1853    if (ObjCIvarDecl *FoundIvar = dyn_cast<ObjCIvarDecl>(*Lookup.first)) {
1854      if (Importer.IsStructurallyEquivalent(D->getType(),
1855                                            FoundIvar->getType())) {
1856        Importer.Imported(D, FoundIvar);
1857        return FoundIvar;
1858      }
1859
1860      Importer.ToDiag(Loc, diag::err_odr_ivar_type_inconsistent)
1861        << Name << D->getType() << FoundIvar->getType();
1862      Importer.ToDiag(FoundIvar->getLocation(), diag::note_odr_value_here)
1863        << FoundIvar->getType();
1864      return 0;
1865    }
1866  }
1867
1868  // Import the type.
1869  QualType T = Importer.Import(D->getType());
1870  if (T.isNull())
1871    return 0;
1872
1873  TypeSourceInfo *TInfo = Importer.Import(D->getTypeSourceInfo());
1874  Expr *BitWidth = Importer.Import(D->getBitWidth());
1875  if (!BitWidth && D->getBitWidth())
1876    return 0;
1877
1878  ObjCIvarDecl *ToIvar = ObjCIvarDecl::Create(Importer.getToContext(), DC,
1879                                              Loc, Name.getAsIdentifierInfo(),
1880                                              T, TInfo, D->getAccessControl(),
1881                                              BitWidth);
1882  ToIvar->setLexicalDeclContext(LexicalDC);
1883  Importer.Imported(D, ToIvar);
1884  LexicalDC->addDecl(ToIvar);
1885  return ToIvar;
1886
1887}
1888
1889Decl *ASTNodeImporter::VisitVarDecl(VarDecl *D) {
1890  // Import the major distinguishing characteristics of a variable.
1891  DeclContext *DC, *LexicalDC;
1892  DeclarationName Name;
1893  SourceLocation Loc;
1894  if (ImportDeclParts(D, DC, LexicalDC, Name, Loc))
1895    return 0;
1896
1897  // Try to find a variable in our own ("to") context with the same name and
1898  // in the same context as the variable we're importing.
1899  if (D->isFileVarDecl()) {
1900    VarDecl *MergeWithVar = 0;
1901    llvm::SmallVector<NamedDecl *, 4> ConflictingDecls;
1902    unsigned IDNS = Decl::IDNS_Ordinary;
1903    for (DeclContext::lookup_result Lookup = DC->lookup(Name);
1904         Lookup.first != Lookup.second;
1905         ++Lookup.first) {
1906      if (!(*Lookup.first)->isInIdentifierNamespace(IDNS))
1907        continue;
1908
1909      if (VarDecl *FoundVar = dyn_cast<VarDecl>(*Lookup.first)) {
1910        // We have found a variable that we may need to merge with. Check it.
1911        if (isExternalLinkage(FoundVar->getLinkage()) &&
1912            isExternalLinkage(D->getLinkage())) {
1913          if (Importer.IsStructurallyEquivalent(D->getType(),
1914                                                FoundVar->getType())) {
1915            MergeWithVar = FoundVar;
1916            break;
1917          }
1918
1919          const ArrayType *FoundArray
1920            = Importer.getToContext().getAsArrayType(FoundVar->getType());
1921          const ArrayType *TArray
1922            = Importer.getToContext().getAsArrayType(D->getType());
1923          if (FoundArray && TArray) {
1924            if (isa<IncompleteArrayType>(FoundArray) &&
1925                isa<ConstantArrayType>(TArray)) {
1926              // Import the type.
1927              QualType T = Importer.Import(D->getType());
1928              if (T.isNull())
1929                return 0;
1930
1931              FoundVar->setType(T);
1932              MergeWithVar = FoundVar;
1933              break;
1934            } else if (isa<IncompleteArrayType>(TArray) &&
1935                       isa<ConstantArrayType>(FoundArray)) {
1936              MergeWithVar = FoundVar;
1937              break;
1938            }
1939          }
1940
1941          Importer.ToDiag(Loc, diag::err_odr_variable_type_inconsistent)
1942            << Name << D->getType() << FoundVar->getType();
1943          Importer.ToDiag(FoundVar->getLocation(), diag::note_odr_value_here)
1944            << FoundVar->getType();
1945        }
1946      }
1947
1948      ConflictingDecls.push_back(*Lookup.first);
1949    }
1950
1951    if (MergeWithVar) {
1952      // An equivalent variable with external linkage has been found. Link
1953      // the two declarations, then merge them.
1954      Importer.Imported(D, MergeWithVar);
1955
1956      if (VarDecl *DDef = D->getDefinition()) {
1957        if (VarDecl *ExistingDef = MergeWithVar->getDefinition()) {
1958          Importer.ToDiag(ExistingDef->getLocation(),
1959                          diag::err_odr_variable_multiple_def)
1960            << Name;
1961          Importer.FromDiag(DDef->getLocation(), diag::note_odr_defined_here);
1962        } else {
1963          Expr *Init = Importer.Import(DDef->getInit());
1964          MergeWithVar->setInit(Init);
1965        }
1966      }
1967
1968      return MergeWithVar;
1969    }
1970
1971    if (!ConflictingDecls.empty()) {
1972      Name = Importer.HandleNameConflict(Name, DC, IDNS,
1973                                         ConflictingDecls.data(),
1974                                         ConflictingDecls.size());
1975      if (!Name)
1976        return 0;
1977    }
1978  }
1979
1980  // Import the type.
1981  QualType T = Importer.Import(D->getType());
1982  if (T.isNull())
1983    return 0;
1984
1985  // Create the imported variable.
1986  TypeSourceInfo *TInfo = Importer.Import(D->getTypeSourceInfo());
1987  VarDecl *ToVar = VarDecl::Create(Importer.getToContext(), DC, Loc,
1988                                   Name.getAsIdentifierInfo(), T, TInfo,
1989                                   D->getStorageClass());
1990  ToVar->setLexicalDeclContext(LexicalDC);
1991  Importer.Imported(D, ToVar);
1992  LexicalDC->addDecl(ToVar);
1993
1994  // Merge the initializer.
1995  // FIXME: Can we really import any initializer? Alternatively, we could force
1996  // ourselves to import every declaration of a variable and then only use
1997  // getInit() here.
1998  ToVar->setInit(Importer.Import(const_cast<Expr *>(D->getAnyInitializer())));
1999
2000  // FIXME: Other bits to merge?
2001
2002  return ToVar;
2003}
2004
2005Decl *ASTNodeImporter::VisitImplicitParamDecl(ImplicitParamDecl *D) {
2006  // Parameters are created in the translation unit's context, then moved
2007  // into the function declaration's context afterward.
2008  DeclContext *DC = Importer.getToContext().getTranslationUnitDecl();
2009
2010  // Import the name of this declaration.
2011  DeclarationName Name = Importer.Import(D->getDeclName());
2012  if (D->getDeclName() && !Name)
2013    return 0;
2014
2015  // Import the location of this declaration.
2016  SourceLocation Loc = Importer.Import(D->getLocation());
2017
2018  // Import the parameter's type.
2019  QualType T = Importer.Import(D->getType());
2020  if (T.isNull())
2021    return 0;
2022
2023  // Create the imported parameter.
2024  ImplicitParamDecl *ToParm
2025    = ImplicitParamDecl::Create(Importer.getToContext(), DC,
2026                                Loc, Name.getAsIdentifierInfo(),
2027                                T);
2028  return Importer.Imported(D, ToParm);
2029}
2030
2031Decl *ASTNodeImporter::VisitParmVarDecl(ParmVarDecl *D) {
2032  // Parameters are created in the translation unit's context, then moved
2033  // into the function declaration's context afterward.
2034  DeclContext *DC = Importer.getToContext().getTranslationUnitDecl();
2035
2036  // Import the name of this declaration.
2037  DeclarationName Name = Importer.Import(D->getDeclName());
2038  if (D->getDeclName() && !Name)
2039    return 0;
2040
2041  // Import the location of this declaration.
2042  SourceLocation Loc = Importer.Import(D->getLocation());
2043
2044  // Import the parameter's type.
2045  QualType T = Importer.Import(D->getType());
2046  if (T.isNull())
2047    return 0;
2048
2049  // Create the imported parameter.
2050  TypeSourceInfo *TInfo = Importer.Import(D->getTypeSourceInfo());
2051  ParmVarDecl *ToParm = ParmVarDecl::Create(Importer.getToContext(), DC,
2052                                            Loc, Name.getAsIdentifierInfo(),
2053                                            T, TInfo, D->getStorageClass(),
2054                                            /*FIXME: Default argument*/ 0);
2055  return Importer.Imported(D, ToParm);
2056}
2057
2058Decl *ASTNodeImporter::VisitObjCMethodDecl(ObjCMethodDecl *D) {
2059  // Import the major distinguishing characteristics of a method.
2060  DeclContext *DC, *LexicalDC;
2061  DeclarationName Name;
2062  SourceLocation Loc;
2063  if (ImportDeclParts(D, DC, LexicalDC, Name, Loc))
2064    return 0;
2065
2066  for (DeclContext::lookup_result Lookup = DC->lookup(Name);
2067       Lookup.first != Lookup.second;
2068       ++Lookup.first) {
2069    if (ObjCMethodDecl *FoundMethod = dyn_cast<ObjCMethodDecl>(*Lookup.first)) {
2070      if (FoundMethod->isInstanceMethod() != D->isInstanceMethod())
2071        continue;
2072
2073      // Check return types.
2074      if (!Importer.IsStructurallyEquivalent(D->getResultType(),
2075                                             FoundMethod->getResultType())) {
2076        Importer.ToDiag(Loc, diag::err_odr_objc_method_result_type_inconsistent)
2077          << D->isInstanceMethod() << Name
2078          << D->getResultType() << FoundMethod->getResultType();
2079        Importer.ToDiag(FoundMethod->getLocation(),
2080                        diag::note_odr_objc_method_here)
2081          << D->isInstanceMethod() << Name;
2082        return 0;
2083      }
2084
2085      // Check the number of parameters.
2086      if (D->param_size() != FoundMethod->param_size()) {
2087        Importer.ToDiag(Loc, diag::err_odr_objc_method_num_params_inconsistent)
2088          << D->isInstanceMethod() << Name
2089          << D->param_size() << FoundMethod->param_size();
2090        Importer.ToDiag(FoundMethod->getLocation(),
2091                        diag::note_odr_objc_method_here)
2092          << D->isInstanceMethod() << Name;
2093        return 0;
2094      }
2095
2096      // Check parameter types.
2097      for (ObjCMethodDecl::param_iterator P = D->param_begin(),
2098             PEnd = D->param_end(), FoundP = FoundMethod->param_begin();
2099           P != PEnd; ++P, ++FoundP) {
2100        if (!Importer.IsStructurallyEquivalent((*P)->getType(),
2101                                               (*FoundP)->getType())) {
2102          Importer.FromDiag((*P)->getLocation(),
2103                            diag::err_odr_objc_method_param_type_inconsistent)
2104            << D->isInstanceMethod() << Name
2105            << (*P)->getType() << (*FoundP)->getType();
2106          Importer.ToDiag((*FoundP)->getLocation(), diag::note_odr_value_here)
2107            << (*FoundP)->getType();
2108          return 0;
2109        }
2110      }
2111
2112      // Check variadic/non-variadic.
2113      // Check the number of parameters.
2114      if (D->isVariadic() != FoundMethod->isVariadic()) {
2115        Importer.ToDiag(Loc, diag::err_odr_objc_method_variadic_inconsistent)
2116          << D->isInstanceMethod() << Name;
2117        Importer.ToDiag(FoundMethod->getLocation(),
2118                        diag::note_odr_objc_method_here)
2119          << D->isInstanceMethod() << Name;
2120        return 0;
2121      }
2122
2123      // FIXME: Any other bits we need to merge?
2124      return Importer.Imported(D, FoundMethod);
2125    }
2126  }
2127
2128  // Import the result type.
2129  QualType ResultTy = Importer.Import(D->getResultType());
2130  if (ResultTy.isNull())
2131    return 0;
2132
2133  ObjCMethodDecl *ToMethod
2134    = ObjCMethodDecl::Create(Importer.getToContext(),
2135                             Loc,
2136                             Importer.Import(D->getLocEnd()),
2137                             Name.getObjCSelector(),
2138                             ResultTy, DC,
2139                             D->isInstanceMethod(),
2140                             D->isVariadic(),
2141                             D->isSynthesized(),
2142                             D->getImplementationControl());
2143
2144  // FIXME: When we decide to merge method definitions, we'll need to
2145  // deal with implicit parameters.
2146
2147  // Import the parameters
2148  llvm::SmallVector<ParmVarDecl *, 5> ToParams;
2149  for (ObjCMethodDecl::param_iterator FromP = D->param_begin(),
2150                                   FromPEnd = D->param_end();
2151       FromP != FromPEnd;
2152       ++FromP) {
2153    ParmVarDecl *ToP = cast_or_null<ParmVarDecl>(Importer.Import(*FromP));
2154    if (!ToP)
2155      return 0;
2156
2157    ToParams.push_back(ToP);
2158  }
2159
2160  // Set the parameters.
2161  for (unsigned I = 0, N = ToParams.size(); I != N; ++I) {
2162    ToParams[I]->setOwningFunction(ToMethod);
2163    ToMethod->addDecl(ToParams[I]);
2164  }
2165  ToMethod->setMethodParams(Importer.getToContext(),
2166                            ToParams.data(), ToParams.size());
2167
2168  ToMethod->setLexicalDeclContext(LexicalDC);
2169  Importer.Imported(D, ToMethod);
2170  LexicalDC->addDecl(ToMethod);
2171  return ToMethod;
2172}
2173
2174Decl *ASTNodeImporter::VisitObjCCategoryDecl(ObjCCategoryDecl *D) {
2175  // Import the major distinguishing characteristics of a category.
2176  DeclContext *DC, *LexicalDC;
2177  DeclarationName Name;
2178  SourceLocation Loc;
2179  if (ImportDeclParts(D, DC, LexicalDC, Name, Loc))
2180    return 0;
2181
2182  ObjCInterfaceDecl *ToInterface
2183    = cast_or_null<ObjCInterfaceDecl>(Importer.Import(D->getClassInterface()));
2184  if (!ToInterface)
2185    return 0;
2186
2187  // Determine if we've already encountered this category.
2188  ObjCCategoryDecl *MergeWithCategory
2189    = ToInterface->FindCategoryDeclaration(Name.getAsIdentifierInfo());
2190  ObjCCategoryDecl *ToCategory = MergeWithCategory;
2191  if (!ToCategory) {
2192    ToCategory = ObjCCategoryDecl::Create(Importer.getToContext(), DC,
2193                                          Importer.Import(D->getAtLoc()),
2194                                          Loc,
2195                                       Importer.Import(D->getCategoryNameLoc()),
2196                                          Name.getAsIdentifierInfo());
2197    ToCategory->setLexicalDeclContext(LexicalDC);
2198    LexicalDC->addDecl(ToCategory);
2199    Importer.Imported(D, ToCategory);
2200
2201    // Link this category into its class's category list.
2202    ToCategory->setClassInterface(ToInterface);
2203    ToCategory->insertNextClassCategory();
2204
2205    // Import protocols
2206    llvm::SmallVector<ObjCProtocolDecl *, 4> Protocols;
2207    llvm::SmallVector<SourceLocation, 4> ProtocolLocs;
2208    ObjCCategoryDecl::protocol_loc_iterator FromProtoLoc
2209      = D->protocol_loc_begin();
2210    for (ObjCCategoryDecl::protocol_iterator FromProto = D->protocol_begin(),
2211                                          FromProtoEnd = D->protocol_end();
2212         FromProto != FromProtoEnd;
2213         ++FromProto, ++FromProtoLoc) {
2214      ObjCProtocolDecl *ToProto
2215        = cast_or_null<ObjCProtocolDecl>(Importer.Import(*FromProto));
2216      if (!ToProto)
2217        return 0;
2218      Protocols.push_back(ToProto);
2219      ProtocolLocs.push_back(Importer.Import(*FromProtoLoc));
2220    }
2221
2222    // FIXME: If we're merging, make sure that the protocol list is the same.
2223    ToCategory->setProtocolList(Protocols.data(), Protocols.size(),
2224                                ProtocolLocs.data(), Importer.getToContext());
2225
2226  } else {
2227    Importer.Imported(D, ToCategory);
2228  }
2229
2230  // Import all of the members of this category.
2231  for (DeclContext::decl_iterator FromMem = D->decls_begin(),
2232                              FromMemEnd = D->decls_end();
2233       FromMem != FromMemEnd;
2234       ++FromMem)
2235    Importer.Import(*FromMem);
2236
2237  // If we have an implementation, import it as well.
2238  if (D->getImplementation()) {
2239    ObjCCategoryImplDecl *Impl
2240      = cast<ObjCCategoryImplDecl>(Importer.Import(D->getImplementation()));
2241    if (!Impl)
2242      return 0;
2243
2244    ToCategory->setImplementation(Impl);
2245  }
2246
2247  return ToCategory;
2248}
2249
2250Decl *ASTNodeImporter::VisitObjCProtocolDecl(ObjCProtocolDecl *D) {
2251  // Import the major distinguishing characteristics of a protocol.
2252  DeclContext *DC, *LexicalDC;
2253  DeclarationName Name;
2254  SourceLocation Loc;
2255  if (ImportDeclParts(D, DC, LexicalDC, Name, Loc))
2256    return 0;
2257
2258  ObjCProtocolDecl *MergeWithProtocol = 0;
2259  for (DeclContext::lookup_result Lookup = DC->lookup(Name);
2260       Lookup.first != Lookup.second;
2261       ++Lookup.first) {
2262    if (!(*Lookup.first)->isInIdentifierNamespace(Decl::IDNS_ObjCProtocol))
2263      continue;
2264
2265    if ((MergeWithProtocol = dyn_cast<ObjCProtocolDecl>(*Lookup.first)))
2266      break;
2267  }
2268
2269  ObjCProtocolDecl *ToProto = MergeWithProtocol;
2270  if (!ToProto || ToProto->isForwardDecl()) {
2271    if (!ToProto) {
2272      ToProto = ObjCProtocolDecl::Create(Importer.getToContext(), DC, Loc,
2273                                         Name.getAsIdentifierInfo());
2274      ToProto->setForwardDecl(D->isForwardDecl());
2275      ToProto->setLexicalDeclContext(LexicalDC);
2276      LexicalDC->addDecl(ToProto);
2277    }
2278    Importer.Imported(D, ToProto);
2279
2280    // Import protocols
2281    llvm::SmallVector<ObjCProtocolDecl *, 4> Protocols;
2282    llvm::SmallVector<SourceLocation, 4> ProtocolLocs;
2283    ObjCProtocolDecl::protocol_loc_iterator
2284      FromProtoLoc = D->protocol_loc_begin();
2285    for (ObjCProtocolDecl::protocol_iterator FromProto = D->protocol_begin(),
2286                                          FromProtoEnd = D->protocol_end();
2287       FromProto != FromProtoEnd;
2288       ++FromProto, ++FromProtoLoc) {
2289      ObjCProtocolDecl *ToProto
2290        = cast_or_null<ObjCProtocolDecl>(Importer.Import(*FromProto));
2291      if (!ToProto)
2292        return 0;
2293      Protocols.push_back(ToProto);
2294      ProtocolLocs.push_back(Importer.Import(*FromProtoLoc));
2295    }
2296
2297    // FIXME: If we're merging, make sure that the protocol list is the same.
2298    ToProto->setProtocolList(Protocols.data(), Protocols.size(),
2299                             ProtocolLocs.data(), Importer.getToContext());
2300  } else {
2301    Importer.Imported(D, ToProto);
2302  }
2303
2304  // Import all of the members of this protocol.
2305  for (DeclContext::decl_iterator FromMem = D->decls_begin(),
2306                               FromMemEnd = D->decls_end();
2307       FromMem != FromMemEnd;
2308       ++FromMem)
2309    Importer.Import(*FromMem);
2310
2311  return ToProto;
2312}
2313
2314Decl *ASTNodeImporter::VisitObjCInterfaceDecl(ObjCInterfaceDecl *D) {
2315  // Import the major distinguishing characteristics of an @interface.
2316  DeclContext *DC, *LexicalDC;
2317  DeclarationName Name;
2318  SourceLocation Loc;
2319  if (ImportDeclParts(D, DC, LexicalDC, Name, Loc))
2320    return 0;
2321
2322  ObjCInterfaceDecl *MergeWithIface = 0;
2323  for (DeclContext::lookup_result Lookup = DC->lookup(Name);
2324       Lookup.first != Lookup.second;
2325       ++Lookup.first) {
2326    if (!(*Lookup.first)->isInIdentifierNamespace(Decl::IDNS_Ordinary))
2327      continue;
2328
2329    if ((MergeWithIface = dyn_cast<ObjCInterfaceDecl>(*Lookup.first)))
2330      break;
2331  }
2332
2333  ObjCInterfaceDecl *ToIface = MergeWithIface;
2334  if (!ToIface || ToIface->isForwardDecl()) {
2335    if (!ToIface) {
2336      ToIface = ObjCInterfaceDecl::Create(Importer.getToContext(),
2337                                          DC, Loc,
2338                                          Name.getAsIdentifierInfo(),
2339                                          Importer.Import(D->getClassLoc()),
2340                                          D->isForwardDecl(),
2341                                          D->isImplicitInterfaceDecl());
2342      ToIface->setForwardDecl(D->isForwardDecl());
2343      ToIface->setLexicalDeclContext(LexicalDC);
2344      LexicalDC->addDecl(ToIface);
2345    }
2346    Importer.Imported(D, ToIface);
2347
2348    if (D->getSuperClass()) {
2349      ObjCInterfaceDecl *Super
2350        = cast_or_null<ObjCInterfaceDecl>(Importer.Import(D->getSuperClass()));
2351      if (!Super)
2352        return 0;
2353
2354      ToIface->setSuperClass(Super);
2355      ToIface->setSuperClassLoc(Importer.Import(D->getSuperClassLoc()));
2356    }
2357
2358    // Import protocols
2359    llvm::SmallVector<ObjCProtocolDecl *, 4> Protocols;
2360    llvm::SmallVector<SourceLocation, 4> ProtocolLocs;
2361    ObjCInterfaceDecl::protocol_loc_iterator
2362      FromProtoLoc = D->protocol_loc_begin();
2363    for (ObjCInterfaceDecl::protocol_iterator FromProto = D->protocol_begin(),
2364                                           FromProtoEnd = D->protocol_end();
2365       FromProto != FromProtoEnd;
2366       ++FromProto, ++FromProtoLoc) {
2367      ObjCProtocolDecl *ToProto
2368        = cast_or_null<ObjCProtocolDecl>(Importer.Import(*FromProto));
2369      if (!ToProto)
2370        return 0;
2371      Protocols.push_back(ToProto);
2372      ProtocolLocs.push_back(Importer.Import(*FromProtoLoc));
2373    }
2374
2375    // FIXME: If we're merging, make sure that the protocol list is the same.
2376    ToIface->setProtocolList(Protocols.data(), Protocols.size(),
2377                             ProtocolLocs.data(), Importer.getToContext());
2378
2379    // Import @end range
2380    ToIface->setAtEndRange(Importer.Import(D->getAtEndRange()));
2381  } else {
2382    Importer.Imported(D, ToIface);
2383
2384    // Check for consistency of superclasses.
2385    DeclarationName FromSuperName, ToSuperName;
2386    if (D->getSuperClass())
2387      FromSuperName = Importer.Import(D->getSuperClass()->getDeclName());
2388    if (ToIface->getSuperClass())
2389      ToSuperName = ToIface->getSuperClass()->getDeclName();
2390    if (FromSuperName != ToSuperName) {
2391      Importer.ToDiag(ToIface->getLocation(),
2392                      diag::err_odr_objc_superclass_inconsistent)
2393        << ToIface->getDeclName();
2394      if (ToIface->getSuperClass())
2395        Importer.ToDiag(ToIface->getSuperClassLoc(),
2396                        diag::note_odr_objc_superclass)
2397          << ToIface->getSuperClass()->getDeclName();
2398      else
2399        Importer.ToDiag(ToIface->getLocation(),
2400                        diag::note_odr_objc_missing_superclass);
2401      if (D->getSuperClass())
2402        Importer.FromDiag(D->getSuperClassLoc(),
2403                          diag::note_odr_objc_superclass)
2404          << D->getSuperClass()->getDeclName();
2405      else
2406        Importer.FromDiag(D->getLocation(),
2407                          diag::note_odr_objc_missing_superclass);
2408      return 0;
2409    }
2410  }
2411
2412  // Import categories. When the categories themselves are imported, they'll
2413  // hook themselves into this interface.
2414  for (ObjCCategoryDecl *FromCat = D->getCategoryList(); FromCat;
2415       FromCat = FromCat->getNextClassCategory())
2416    Importer.Import(FromCat);
2417
2418  // Import all of the members of this class.
2419  for (DeclContext::decl_iterator FromMem = D->decls_begin(),
2420                               FromMemEnd = D->decls_end();
2421       FromMem != FromMemEnd;
2422       ++FromMem)
2423    Importer.Import(*FromMem);
2424
2425  // If we have an @implementation, import it as well.
2426  if (D->getImplementation()) {
2427    ObjCImplementationDecl *Impl
2428      = cast<ObjCImplementationDecl>(Importer.Import(D->getImplementation()));
2429    if (!Impl)
2430      return 0;
2431
2432    ToIface->setImplementation(Impl);
2433  }
2434
2435  return ToIface;
2436}
2437
2438Decl *ASTNodeImporter::VisitObjCPropertyDecl(ObjCPropertyDecl *D) {
2439  // Import the major distinguishing characteristics of an @property.
2440  DeclContext *DC, *LexicalDC;
2441  DeclarationName Name;
2442  SourceLocation Loc;
2443  if (ImportDeclParts(D, DC, LexicalDC, Name, Loc))
2444    return 0;
2445
2446  // Check whether we have already imported this property.
2447  for (DeclContext::lookup_result Lookup = DC->lookup(Name);
2448       Lookup.first != Lookup.second;
2449       ++Lookup.first) {
2450    if (ObjCPropertyDecl *FoundProp
2451                                = dyn_cast<ObjCPropertyDecl>(*Lookup.first)) {
2452      // Check property types.
2453      if (!Importer.IsStructurallyEquivalent(D->getType(),
2454                                             FoundProp->getType())) {
2455        Importer.ToDiag(Loc, diag::err_odr_objc_property_type_inconsistent)
2456          << Name << D->getType() << FoundProp->getType();
2457        Importer.ToDiag(FoundProp->getLocation(), diag::note_odr_value_here)
2458          << FoundProp->getType();
2459        return 0;
2460      }
2461
2462      // FIXME: Check property attributes, getters, setters, etc.?
2463
2464      // Consider these properties to be equivalent.
2465      Importer.Imported(D, FoundProp);
2466      return FoundProp;
2467    }
2468  }
2469
2470  // Import the type.
2471  QualType T = Importer.Import(D->getType());
2472  if (T.isNull())
2473    return 0;
2474
2475  // Create the new property.
2476  ObjCPropertyDecl *ToProperty
2477    = ObjCPropertyDecl::Create(Importer.getToContext(), DC, Loc,
2478                               Name.getAsIdentifierInfo(),
2479                               Importer.Import(D->getAtLoc()),
2480                               T,
2481                               D->getPropertyImplementation());
2482  Importer.Imported(D, ToProperty);
2483  ToProperty->setLexicalDeclContext(LexicalDC);
2484  LexicalDC->addDecl(ToProperty);
2485
2486  ToProperty->setPropertyAttributes(D->getPropertyAttributes());
2487  ToProperty->setGetterName(Importer.Import(D->getGetterName()));
2488  ToProperty->setSetterName(Importer.Import(D->getSetterName()));
2489  ToProperty->setGetterMethodDecl(
2490     cast_or_null<ObjCMethodDecl>(Importer.Import(D->getGetterMethodDecl())));
2491  ToProperty->setSetterMethodDecl(
2492     cast_or_null<ObjCMethodDecl>(Importer.Import(D->getSetterMethodDecl())));
2493  ToProperty->setPropertyIvarDecl(
2494       cast_or_null<ObjCIvarDecl>(Importer.Import(D->getPropertyIvarDecl())));
2495  return ToProperty;
2496}
2497
2498Decl *
2499ASTNodeImporter::VisitObjCForwardProtocolDecl(ObjCForwardProtocolDecl *D) {
2500  // Import the context of this declaration.
2501  DeclContext *DC = Importer.ImportContext(D->getDeclContext());
2502  if (!DC)
2503    return 0;
2504
2505  DeclContext *LexicalDC = DC;
2506  if (D->getDeclContext() != D->getLexicalDeclContext()) {
2507    LexicalDC = Importer.ImportContext(D->getLexicalDeclContext());
2508    if (!LexicalDC)
2509      return 0;
2510  }
2511
2512  // Import the location of this declaration.
2513  SourceLocation Loc = Importer.Import(D->getLocation());
2514
2515  llvm::SmallVector<ObjCProtocolDecl *, 4> Protocols;
2516  llvm::SmallVector<SourceLocation, 4> Locations;
2517  ObjCForwardProtocolDecl::protocol_loc_iterator FromProtoLoc
2518    = D->protocol_loc_begin();
2519  for (ObjCForwardProtocolDecl::protocol_iterator FromProto
2520         = D->protocol_begin(), FromProtoEnd = D->protocol_end();
2521       FromProto != FromProtoEnd;
2522       ++FromProto, ++FromProtoLoc) {
2523    ObjCProtocolDecl *ToProto
2524      = cast_or_null<ObjCProtocolDecl>(Importer.Import(*FromProto));
2525    if (!ToProto)
2526      continue;
2527
2528    Protocols.push_back(ToProto);
2529    Locations.push_back(Importer.Import(*FromProtoLoc));
2530  }
2531
2532  ObjCForwardProtocolDecl *ToForward
2533    = ObjCForwardProtocolDecl::Create(Importer.getToContext(), DC, Loc,
2534                                      Protocols.data(), Protocols.size(),
2535                                      Locations.data());
2536  ToForward->setLexicalDeclContext(LexicalDC);
2537  LexicalDC->addDecl(ToForward);
2538  Importer.Imported(D, ToForward);
2539  return ToForward;
2540}
2541
2542Decl *ASTNodeImporter::VisitObjCClassDecl(ObjCClassDecl *D) {
2543  // Import the context of this declaration.
2544  DeclContext *DC = Importer.ImportContext(D->getDeclContext());
2545  if (!DC)
2546    return 0;
2547
2548  DeclContext *LexicalDC = DC;
2549  if (D->getDeclContext() != D->getLexicalDeclContext()) {
2550    LexicalDC = Importer.ImportContext(D->getLexicalDeclContext());
2551    if (!LexicalDC)
2552      return 0;
2553  }
2554
2555  // Import the location of this declaration.
2556  SourceLocation Loc = Importer.Import(D->getLocation());
2557
2558  llvm::SmallVector<ObjCInterfaceDecl *, 4> Interfaces;
2559  llvm::SmallVector<SourceLocation, 4> Locations;
2560  for (ObjCClassDecl::iterator From = D->begin(), FromEnd = D->end();
2561       From != FromEnd; ++From) {
2562    ObjCInterfaceDecl *ToIface
2563      = cast_or_null<ObjCInterfaceDecl>(Importer.Import(From->getInterface()));
2564    if (!ToIface)
2565      continue;
2566
2567    Interfaces.push_back(ToIface);
2568    Locations.push_back(Importer.Import(From->getLocation()));
2569  }
2570
2571  ObjCClassDecl *ToClass = ObjCClassDecl::Create(Importer.getToContext(), DC,
2572                                                 Loc,
2573                                                 Interfaces.data(),
2574                                                 Locations.data(),
2575                                                 Interfaces.size());
2576  ToClass->setLexicalDeclContext(LexicalDC);
2577  LexicalDC->addDecl(ToClass);
2578  Importer.Imported(D, ToClass);
2579  return ToClass;
2580}
2581
2582//----------------------------------------------------------------------------
2583// Import Statements
2584//----------------------------------------------------------------------------
2585
2586Stmt *ASTNodeImporter::VisitStmt(Stmt *S) {
2587  Importer.FromDiag(S->getLocStart(), diag::err_unsupported_ast_node)
2588    << S->getStmtClassName();
2589  return 0;
2590}
2591
2592//----------------------------------------------------------------------------
2593// Import Expressions
2594//----------------------------------------------------------------------------
2595Expr *ASTNodeImporter::VisitExpr(Expr *E) {
2596  Importer.FromDiag(E->getLocStart(), diag::err_unsupported_ast_node)
2597    << E->getStmtClassName();
2598  return 0;
2599}
2600
2601Expr *ASTNodeImporter::VisitDeclRefExpr(DeclRefExpr *E) {
2602  NestedNameSpecifier *Qualifier = 0;
2603  if (E->getQualifier()) {
2604    Qualifier = Importer.Import(E->getQualifier());
2605    if (!E->getQualifier())
2606      return 0;
2607  }
2608
2609  ValueDecl *ToD = cast_or_null<ValueDecl>(Importer.Import(E->getDecl()));
2610  if (!ToD)
2611    return 0;
2612
2613  QualType T = Importer.Import(E->getType());
2614  if (T.isNull())
2615    return 0;
2616
2617  return DeclRefExpr::Create(Importer.getToContext(), Qualifier,
2618                             Importer.Import(E->getQualifierRange()),
2619                             ToD,
2620                             Importer.Import(E->getLocation()),
2621                             T,
2622                             /*FIXME:TemplateArgs=*/0);
2623}
2624
2625Expr *ASTNodeImporter::VisitIntegerLiteral(IntegerLiteral *E) {
2626  QualType T = Importer.Import(E->getType());
2627  if (T.isNull())
2628    return 0;
2629
2630  return new (Importer.getToContext())
2631    IntegerLiteral(E->getValue(), T, Importer.Import(E->getLocation()));
2632}
2633
2634Expr *ASTNodeImporter::VisitCharacterLiteral(CharacterLiteral *E) {
2635  QualType T = Importer.Import(E->getType());
2636  if (T.isNull())
2637    return 0;
2638
2639  return new (Importer.getToContext()) CharacterLiteral(E->getValue(),
2640                                                        E->isWide(), T,
2641                                          Importer.Import(E->getLocation()));
2642}
2643
2644Expr *ASTNodeImporter::VisitParenExpr(ParenExpr *E) {
2645  Expr *SubExpr = Importer.Import(E->getSubExpr());
2646  if (!SubExpr)
2647    return 0;
2648
2649  return new (Importer.getToContext())
2650                                  ParenExpr(Importer.Import(E->getLParen()),
2651                                            Importer.Import(E->getRParen()),
2652                                            SubExpr);
2653}
2654
2655Expr *ASTNodeImporter::VisitUnaryOperator(UnaryOperator *E) {
2656  QualType T = Importer.Import(E->getType());
2657  if (T.isNull())
2658    return 0;
2659
2660  Expr *SubExpr = Importer.Import(E->getSubExpr());
2661  if (!SubExpr)
2662    return 0;
2663
2664  return new (Importer.getToContext()) UnaryOperator(SubExpr, E->getOpcode(),
2665                                                     T,
2666                                         Importer.Import(E->getOperatorLoc()));
2667}
2668
2669Expr *ASTNodeImporter::VisitSizeOfAlignOfExpr(SizeOfAlignOfExpr *E) {
2670  QualType ResultType = Importer.Import(E->getType());
2671
2672  if (E->isArgumentType()) {
2673    TypeSourceInfo *TInfo = Importer.Import(E->getArgumentTypeInfo());
2674    if (!TInfo)
2675      return 0;
2676
2677    return new (Importer.getToContext()) SizeOfAlignOfExpr(E->isSizeOf(),
2678                                                           TInfo, ResultType,
2679                                           Importer.Import(E->getOperatorLoc()),
2680                                           Importer.Import(E->getRParenLoc()));
2681  }
2682
2683  Expr *SubExpr = Importer.Import(E->getArgumentExpr());
2684  if (!SubExpr)
2685    return 0;
2686
2687  return new (Importer.getToContext()) SizeOfAlignOfExpr(E->isSizeOf(),
2688                                                         SubExpr, ResultType,
2689                                          Importer.Import(E->getOperatorLoc()),
2690                                          Importer.Import(E->getRParenLoc()));
2691}
2692
2693Expr *ASTNodeImporter::VisitBinaryOperator(BinaryOperator *E) {
2694  QualType T = Importer.Import(E->getType());
2695  if (T.isNull())
2696    return 0;
2697
2698  Expr *LHS = Importer.Import(E->getLHS());
2699  if (!LHS)
2700    return 0;
2701
2702  Expr *RHS = Importer.Import(E->getRHS());
2703  if (!RHS)
2704    return 0;
2705
2706  return new (Importer.getToContext()) BinaryOperator(LHS, RHS, E->getOpcode(),
2707                                                      T,
2708                                          Importer.Import(E->getOperatorLoc()));
2709}
2710
2711Expr *ASTNodeImporter::VisitCompoundAssignOperator(CompoundAssignOperator *E) {
2712  QualType T = Importer.Import(E->getType());
2713  if (T.isNull())
2714    return 0;
2715
2716  QualType CompLHSType = Importer.Import(E->getComputationLHSType());
2717  if (CompLHSType.isNull())
2718    return 0;
2719
2720  QualType CompResultType = Importer.Import(E->getComputationResultType());
2721  if (CompResultType.isNull())
2722    return 0;
2723
2724  Expr *LHS = Importer.Import(E->getLHS());
2725  if (!LHS)
2726    return 0;
2727
2728  Expr *RHS = Importer.Import(E->getRHS());
2729  if (!RHS)
2730    return 0;
2731
2732  return new (Importer.getToContext())
2733                        CompoundAssignOperator(LHS, RHS, E->getOpcode(),
2734                                               T, CompLHSType, CompResultType,
2735                                          Importer.Import(E->getOperatorLoc()));
2736}
2737
2738Expr *ASTNodeImporter::VisitImplicitCastExpr(ImplicitCastExpr *E) {
2739  QualType T = Importer.Import(E->getType());
2740  if (T.isNull())
2741    return 0;
2742
2743  Expr *SubExpr = Importer.Import(E->getSubExpr());
2744  if (!SubExpr)
2745    return 0;
2746
2747  return new (Importer.getToContext()) ImplicitCastExpr(T, E->getCastKind(),
2748                                                        SubExpr,
2749                                                        E->isLvalueCast());
2750}
2751
2752Expr *ASTNodeImporter::VisitCStyleCastExpr(CStyleCastExpr *E) {
2753  QualType T = Importer.Import(E->getType());
2754  if (T.isNull())
2755    return 0;
2756
2757  Expr *SubExpr = Importer.Import(E->getSubExpr());
2758  if (!SubExpr)
2759    return 0;
2760
2761  TypeSourceInfo *TInfo = Importer.Import(E->getTypeInfoAsWritten());
2762  if (!TInfo && E->getTypeInfoAsWritten())
2763    return 0;
2764
2765  return new (Importer.getToContext()) CStyleCastExpr(T, E->getCastKind(),
2766                                                      SubExpr, TInfo,
2767                                            Importer.Import(E->getLParenLoc()),
2768                                            Importer.Import(E->getRParenLoc()));
2769}
2770
2771ASTImporter::ASTImporter(Diagnostic &Diags,
2772                         ASTContext &ToContext, FileManager &ToFileManager,
2773                         ASTContext &FromContext, FileManager &FromFileManager)
2774  : ToContext(ToContext), FromContext(FromContext),
2775    ToFileManager(ToFileManager), FromFileManager(FromFileManager),
2776    Diags(Diags) {
2777  ImportedDecls[FromContext.getTranslationUnitDecl()]
2778    = ToContext.getTranslationUnitDecl();
2779}
2780
2781ASTImporter::~ASTImporter() { }
2782
2783QualType ASTImporter::Import(QualType FromT) {
2784  if (FromT.isNull())
2785    return QualType();
2786
2787  // Check whether we've already imported this type.
2788  llvm::DenseMap<Type *, Type *>::iterator Pos
2789    = ImportedTypes.find(FromT.getTypePtr());
2790  if (Pos != ImportedTypes.end())
2791    return ToContext.getQualifiedType(Pos->second, FromT.getQualifiers());
2792
2793  // Import the type
2794  ASTNodeImporter Importer(*this);
2795  QualType ToT = Importer.Visit(FromT.getTypePtr());
2796  if (ToT.isNull())
2797    return ToT;
2798
2799  // Record the imported type.
2800  ImportedTypes[FromT.getTypePtr()] = ToT.getTypePtr();
2801
2802  return ToContext.getQualifiedType(ToT, FromT.getQualifiers());
2803}
2804
2805TypeSourceInfo *ASTImporter::Import(TypeSourceInfo *FromTSI) {
2806  if (!FromTSI)
2807    return FromTSI;
2808
2809  // FIXME: For now we just create a "trivial" type source info based
2810  // on the type and a seingle location. Implement a real version of
2811  // this.
2812  QualType T = Import(FromTSI->getType());
2813  if (T.isNull())
2814    return 0;
2815
2816  return ToContext.getTrivialTypeSourceInfo(T,
2817                        FromTSI->getTypeLoc().getFullSourceRange().getBegin());
2818}
2819
2820Decl *ASTImporter::Import(Decl *FromD) {
2821  if (!FromD)
2822    return 0;
2823
2824  // Check whether we've already imported this declaration.
2825  llvm::DenseMap<Decl *, Decl *>::iterator Pos = ImportedDecls.find(FromD);
2826  if (Pos != ImportedDecls.end())
2827    return Pos->second;
2828
2829  // Import the type
2830  ASTNodeImporter Importer(*this);
2831  Decl *ToD = Importer.Visit(FromD);
2832  if (!ToD)
2833    return 0;
2834
2835  // Record the imported declaration.
2836  ImportedDecls[FromD] = ToD;
2837
2838  if (TagDecl *FromTag = dyn_cast<TagDecl>(FromD)) {
2839    // Keep track of anonymous tags that have an associated typedef.
2840    if (FromTag->getTypedefForAnonDecl())
2841      AnonTagsWithPendingTypedefs.push_back(FromTag);
2842  } else if (TypedefDecl *FromTypedef = dyn_cast<TypedefDecl>(FromD)) {
2843    // When we've finished transforming a typedef, see whether it was the
2844    // typedef for an anonymous tag.
2845    for (llvm::SmallVector<TagDecl *, 4>::iterator
2846               FromTag = AnonTagsWithPendingTypedefs.begin(),
2847            FromTagEnd = AnonTagsWithPendingTypedefs.end();
2848         FromTag != FromTagEnd; ++FromTag) {
2849      if ((*FromTag)->getTypedefForAnonDecl() == FromTypedef) {
2850        if (TagDecl *ToTag = cast_or_null<TagDecl>(Import(*FromTag))) {
2851          // We found the typedef for an anonymous tag; link them.
2852          ToTag->setTypedefForAnonDecl(cast<TypedefDecl>(ToD));
2853          AnonTagsWithPendingTypedefs.erase(FromTag);
2854          break;
2855        }
2856      }
2857    }
2858  }
2859
2860  return ToD;
2861}
2862
2863DeclContext *ASTImporter::ImportContext(DeclContext *FromDC) {
2864  if (!FromDC)
2865    return FromDC;
2866
2867  return cast_or_null<DeclContext>(Import(cast<Decl>(FromDC)));
2868}
2869
2870Expr *ASTImporter::Import(Expr *FromE) {
2871  if (!FromE)
2872    return 0;
2873
2874  return cast_or_null<Expr>(Import(cast<Stmt>(FromE)));
2875}
2876
2877Stmt *ASTImporter::Import(Stmt *FromS) {
2878  if (!FromS)
2879    return 0;
2880
2881  // Check whether we've already imported this declaration.
2882  llvm::DenseMap<Stmt *, Stmt *>::iterator Pos = ImportedStmts.find(FromS);
2883  if (Pos != ImportedStmts.end())
2884    return Pos->second;
2885
2886  // Import the type
2887  ASTNodeImporter Importer(*this);
2888  Stmt *ToS = Importer.Visit(FromS);
2889  if (!ToS)
2890    return 0;
2891
2892  // Record the imported declaration.
2893  ImportedStmts[FromS] = ToS;
2894  return ToS;
2895}
2896
2897NestedNameSpecifier *ASTImporter::Import(NestedNameSpecifier *FromNNS) {
2898  if (!FromNNS)
2899    return 0;
2900
2901  // FIXME: Implement!
2902  return 0;
2903}
2904
2905SourceLocation ASTImporter::Import(SourceLocation FromLoc) {
2906  if (FromLoc.isInvalid())
2907    return SourceLocation();
2908
2909  SourceManager &FromSM = FromContext.getSourceManager();
2910
2911  // For now, map everything down to its spelling location, so that we
2912  // don't have to import macro instantiations.
2913  // FIXME: Import macro instantiations!
2914  FromLoc = FromSM.getSpellingLoc(FromLoc);
2915  std::pair<FileID, unsigned> Decomposed = FromSM.getDecomposedLoc(FromLoc);
2916  SourceManager &ToSM = ToContext.getSourceManager();
2917  return ToSM.getLocForStartOfFile(Import(Decomposed.first))
2918             .getFileLocWithOffset(Decomposed.second);
2919}
2920
2921SourceRange ASTImporter::Import(SourceRange FromRange) {
2922  return SourceRange(Import(FromRange.getBegin()), Import(FromRange.getEnd()));
2923}
2924
2925FileID ASTImporter::Import(FileID FromID) {
2926  llvm::DenseMap<unsigned, FileID>::iterator Pos
2927    = ImportedFileIDs.find(FromID.getHashValue());
2928  if (Pos != ImportedFileIDs.end())
2929    return Pos->second;
2930
2931  SourceManager &FromSM = FromContext.getSourceManager();
2932  SourceManager &ToSM = ToContext.getSourceManager();
2933  const SrcMgr::SLocEntry &FromSLoc = FromSM.getSLocEntry(FromID);
2934  assert(FromSLoc.isFile() && "Cannot handle macro instantiations yet");
2935
2936  // Include location of this file.
2937  SourceLocation ToIncludeLoc = Import(FromSLoc.getFile().getIncludeLoc());
2938
2939  // Map the FileID for to the "to" source manager.
2940  FileID ToID;
2941  const SrcMgr::ContentCache *Cache = FromSLoc.getFile().getContentCache();
2942  if (Cache->Entry) {
2943    // FIXME: We probably want to use getVirtualFile(), so we don't hit the
2944    // disk again
2945    // FIXME: We definitely want to re-use the existing MemoryBuffer, rather
2946    // than mmap the files several times.
2947    const FileEntry *Entry = ToFileManager.getFile(Cache->Entry->getName());
2948    ToID = ToSM.createFileID(Entry, ToIncludeLoc,
2949                             FromSLoc.getFile().getFileCharacteristic());
2950  } else {
2951    // FIXME: We want to re-use the existing MemoryBuffer!
2952    const llvm::MemoryBuffer *FromBuf = Cache->getBuffer();
2953    llvm::MemoryBuffer *ToBuf
2954      = llvm::MemoryBuffer::getMemBufferCopy(FromBuf->getBufferStart(),
2955                                             FromBuf->getBufferEnd(),
2956                                             FromBuf->getBufferIdentifier());
2957    ToID = ToSM.createFileIDForMemBuffer(ToBuf);
2958  }
2959
2960
2961  ImportedFileIDs[FromID.getHashValue()] = ToID;
2962  return ToID;
2963}
2964
2965DeclarationName ASTImporter::Import(DeclarationName FromName) {
2966  if (!FromName)
2967    return DeclarationName();
2968
2969  switch (FromName.getNameKind()) {
2970  case DeclarationName::Identifier:
2971    return Import(FromName.getAsIdentifierInfo());
2972
2973  case DeclarationName::ObjCZeroArgSelector:
2974  case DeclarationName::ObjCOneArgSelector:
2975  case DeclarationName::ObjCMultiArgSelector:
2976    return Import(FromName.getObjCSelector());
2977
2978  case DeclarationName::CXXConstructorName: {
2979    QualType T = Import(FromName.getCXXNameType());
2980    if (T.isNull())
2981      return DeclarationName();
2982
2983    return ToContext.DeclarationNames.getCXXConstructorName(
2984                                               ToContext.getCanonicalType(T));
2985  }
2986
2987  case DeclarationName::CXXDestructorName: {
2988    QualType T = Import(FromName.getCXXNameType());
2989    if (T.isNull())
2990      return DeclarationName();
2991
2992    return ToContext.DeclarationNames.getCXXDestructorName(
2993                                               ToContext.getCanonicalType(T));
2994  }
2995
2996  case DeclarationName::CXXConversionFunctionName: {
2997    QualType T = Import(FromName.getCXXNameType());
2998    if (T.isNull())
2999      return DeclarationName();
3000
3001    return ToContext.DeclarationNames.getCXXConversionFunctionName(
3002                                               ToContext.getCanonicalType(T));
3003  }
3004
3005  case DeclarationName::CXXOperatorName:
3006    return ToContext.DeclarationNames.getCXXOperatorName(
3007                                          FromName.getCXXOverloadedOperator());
3008
3009  case DeclarationName::CXXLiteralOperatorName:
3010    return ToContext.DeclarationNames.getCXXLiteralOperatorName(
3011                                   Import(FromName.getCXXLiteralIdentifier()));
3012
3013  case DeclarationName::CXXUsingDirective:
3014    // FIXME: STATICS!
3015    return DeclarationName::getUsingDirectiveName();
3016  }
3017
3018  // Silence bogus GCC warning
3019  return DeclarationName();
3020}
3021
3022IdentifierInfo *ASTImporter::Import(IdentifierInfo *FromId) {
3023  if (!FromId)
3024    return 0;
3025
3026  return &ToContext.Idents.get(FromId->getName());
3027}
3028
3029Selector ASTImporter::Import(Selector FromSel) {
3030  if (FromSel.isNull())
3031    return Selector();
3032
3033  llvm::SmallVector<IdentifierInfo *, 4> Idents;
3034  Idents.push_back(Import(FromSel.getIdentifierInfoForSlot(0)));
3035  for (unsigned I = 1, N = FromSel.getNumArgs(); I < N; ++I)
3036    Idents.push_back(Import(FromSel.getIdentifierInfoForSlot(I)));
3037  return ToContext.Selectors.getSelector(FromSel.getNumArgs(), Idents.data());
3038}
3039
3040DeclarationName ASTImporter::HandleNameConflict(DeclarationName Name,
3041                                                DeclContext *DC,
3042                                                unsigned IDNS,
3043                                                NamedDecl **Decls,
3044                                                unsigned NumDecls) {
3045  return Name;
3046}
3047
3048DiagnosticBuilder ASTImporter::ToDiag(SourceLocation Loc, unsigned DiagID) {
3049  return Diags.Report(FullSourceLoc(Loc, ToContext.getSourceManager()),
3050                      DiagID);
3051}
3052
3053DiagnosticBuilder ASTImporter::FromDiag(SourceLocation Loc, unsigned DiagID) {
3054  return Diags.Report(FullSourceLoc(Loc, FromContext.getSourceManager()),
3055                      DiagID);
3056}
3057
3058Decl *ASTImporter::Imported(Decl *From, Decl *To) {
3059  ImportedDecls[From] = To;
3060  return To;
3061}
3062
3063bool ASTImporter::IsStructurallyEquivalent(QualType From, QualType To) {
3064  llvm::DenseMap<Type *, Type *>::iterator Pos
3065   = ImportedTypes.find(From.getTypePtr());
3066  if (Pos != ImportedTypes.end() && ToContext.hasSameType(Import(From), To))
3067    return true;
3068
3069  StructuralEquivalenceContext Ctx(FromContext, ToContext, Diags,
3070                                   NonEquivalentDecls);
3071  return Ctx.IsStructurallyEquivalent(From, To);
3072}
3073