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 #include "clang/AST/ASTContext.h"
16 #include "clang/AST/ASTDiagnostic.h"
17 #include "clang/AST/DeclCXX.h"
18 #include "clang/AST/DeclObjC.h"
19 #include "clang/AST/DeclVisitor.h"
20 #include "clang/AST/StmtVisitor.h"
21 #include "clang/AST/TypeVisitor.h"
22 #include "clang/Basic/FileManager.h"
23 #include "clang/Basic/SourceManager.h"
24 #include "llvm/Support/MemoryBuffer.h"
25 #include <deque>
26 
27 namespace clang {
28   class ASTNodeImporter : public TypeVisitor<ASTNodeImporter, QualType>,
29                           public DeclVisitor<ASTNodeImporter, Decl *>,
30                           public StmtVisitor<ASTNodeImporter, Stmt *> {
31     ASTImporter &Importer;
32 
33   public:
34     explicit ASTNodeImporter(ASTImporter &Importer) : Importer(Importer) { }
35 
36     using TypeVisitor<ASTNodeImporter, QualType>::Visit;
37     using DeclVisitor<ASTNodeImporter, Decl *>::Visit;
38     using StmtVisitor<ASTNodeImporter, Stmt *>::Visit;
39 
40     // Importing types
41     QualType VisitType(const Type *T);
42     QualType VisitBuiltinType(const BuiltinType *T);
43     QualType VisitComplexType(const ComplexType *T);
44     QualType VisitPointerType(const PointerType *T);
45     QualType VisitBlockPointerType(const BlockPointerType *T);
46     QualType VisitLValueReferenceType(const LValueReferenceType *T);
47     QualType VisitRValueReferenceType(const RValueReferenceType *T);
48     QualType VisitMemberPointerType(const MemberPointerType *T);
49     QualType VisitConstantArrayType(const ConstantArrayType *T);
50     QualType VisitIncompleteArrayType(const IncompleteArrayType *T);
51     QualType VisitVariableArrayType(const VariableArrayType *T);
52     // FIXME: DependentSizedArrayType
53     // FIXME: DependentSizedExtVectorType
54     QualType VisitVectorType(const VectorType *T);
55     QualType VisitExtVectorType(const ExtVectorType *T);
56     QualType VisitFunctionNoProtoType(const FunctionNoProtoType *T);
57     QualType VisitFunctionProtoType(const FunctionProtoType *T);
58     // FIXME: UnresolvedUsingType
59     QualType VisitParenType(const ParenType *T);
60     QualType VisitTypedefType(const TypedefType *T);
61     QualType VisitTypeOfExprType(const TypeOfExprType *T);
62     // FIXME: DependentTypeOfExprType
63     QualType VisitTypeOfType(const TypeOfType *T);
64     QualType VisitDecltypeType(const DecltypeType *T);
65     QualType VisitUnaryTransformType(const UnaryTransformType *T);
66     QualType VisitAutoType(const AutoType *T);
67     // FIXME: DependentDecltypeType
68     QualType VisitRecordType(const RecordType *T);
69     QualType VisitEnumType(const EnumType *T);
70     // FIXME: TemplateTypeParmType
71     // FIXME: SubstTemplateTypeParmType
72     QualType VisitTemplateSpecializationType(const TemplateSpecializationType *T);
73     QualType VisitElaboratedType(const ElaboratedType *T);
74     // FIXME: DependentNameType
75     // FIXME: DependentTemplateSpecializationType
76     QualType VisitObjCInterfaceType(const ObjCInterfaceType *T);
77     QualType VisitObjCObjectType(const ObjCObjectType *T);
78     QualType VisitObjCObjectPointerType(const ObjCObjectPointerType *T);
79 
80     // Importing declarations
81     bool ImportDeclParts(NamedDecl *D, DeclContext *&DC,
82                          DeclContext *&LexicalDC, DeclarationName &Name,
83                          SourceLocation &Loc);
84     void ImportDefinitionIfNeeded(Decl *FromD, Decl *ToD = nullptr);
85     void ImportDeclarationNameLoc(const DeclarationNameInfo &From,
86                                   DeclarationNameInfo& To);
87     void ImportDeclContext(DeclContext *FromDC, bool ForceImport = false);
88 
89     /// \brief What we should import from the definition.
90     enum ImportDefinitionKind {
91       /// \brief Import the default subset of the definition, which might be
92       /// nothing (if minimal import is set) or might be everything (if minimal
93       /// import is not set).
94       IDK_Default,
95       /// \brief Import everything.
96       IDK_Everything,
97       /// \brief Import only the bare bones needed to establish a valid
98       /// DeclContext.
99       IDK_Basic
100     };
101 
102     bool shouldForceImportDeclContext(ImportDefinitionKind IDK) {
103       return IDK == IDK_Everything ||
104              (IDK == IDK_Default && !Importer.isMinimalImport());
105     }
106 
107     bool ImportDefinition(RecordDecl *From, RecordDecl *To,
108                           ImportDefinitionKind Kind = IDK_Default);
109     bool ImportDefinition(VarDecl *From, VarDecl *To,
110                           ImportDefinitionKind Kind = IDK_Default);
111     bool ImportDefinition(EnumDecl *From, EnumDecl *To,
112                           ImportDefinitionKind Kind = IDK_Default);
113     bool ImportDefinition(ObjCInterfaceDecl *From, ObjCInterfaceDecl *To,
114                           ImportDefinitionKind Kind = IDK_Default);
115     bool ImportDefinition(ObjCProtocolDecl *From, ObjCProtocolDecl *To,
116                           ImportDefinitionKind Kind = IDK_Default);
117     TemplateParameterList *ImportTemplateParameterList(
118                                                  TemplateParameterList *Params);
119     TemplateArgument ImportTemplateArgument(const TemplateArgument &From);
120     bool ImportTemplateArguments(const TemplateArgument *FromArgs,
121                                  unsigned NumFromArgs,
122                                SmallVectorImpl<TemplateArgument> &ToArgs);
123     bool IsStructuralMatch(RecordDecl *FromRecord, RecordDecl *ToRecord,
124                            bool Complain = true);
125     bool IsStructuralMatch(VarDecl *FromVar, VarDecl *ToVar,
126                            bool Complain = true);
127     bool IsStructuralMatch(EnumDecl *FromEnum, EnumDecl *ToRecord);
128     bool IsStructuralMatch(EnumConstantDecl *FromEC, EnumConstantDecl *ToEC);
129     bool IsStructuralMatch(ClassTemplateDecl *From, ClassTemplateDecl *To);
130     bool IsStructuralMatch(VarTemplateDecl *From, VarTemplateDecl *To);
131     Decl *VisitDecl(Decl *D);
132     Decl *VisitTranslationUnitDecl(TranslationUnitDecl *D);
133     Decl *VisitNamespaceDecl(NamespaceDecl *D);
134     Decl *VisitTypedefNameDecl(TypedefNameDecl *D, bool IsAlias);
135     Decl *VisitTypedefDecl(TypedefDecl *D);
136     Decl *VisitTypeAliasDecl(TypeAliasDecl *D);
137     Decl *VisitEnumDecl(EnumDecl *D);
138     Decl *VisitRecordDecl(RecordDecl *D);
139     Decl *VisitEnumConstantDecl(EnumConstantDecl *D);
140     Decl *VisitFunctionDecl(FunctionDecl *D);
141     Decl *VisitCXXMethodDecl(CXXMethodDecl *D);
142     Decl *VisitCXXConstructorDecl(CXXConstructorDecl *D);
143     Decl *VisitCXXDestructorDecl(CXXDestructorDecl *D);
144     Decl *VisitCXXConversionDecl(CXXConversionDecl *D);
145     Decl *VisitFieldDecl(FieldDecl *D);
146     Decl *VisitIndirectFieldDecl(IndirectFieldDecl *D);
147     Decl *VisitObjCIvarDecl(ObjCIvarDecl *D);
148     Decl *VisitVarDecl(VarDecl *D);
149     Decl *VisitImplicitParamDecl(ImplicitParamDecl *D);
150     Decl *VisitParmVarDecl(ParmVarDecl *D);
151     Decl *VisitObjCMethodDecl(ObjCMethodDecl *D);
152     Decl *VisitObjCCategoryDecl(ObjCCategoryDecl *D);
153     Decl *VisitObjCProtocolDecl(ObjCProtocolDecl *D);
154     Decl *VisitObjCInterfaceDecl(ObjCInterfaceDecl *D);
155     Decl *VisitObjCCategoryImplDecl(ObjCCategoryImplDecl *D);
156     Decl *VisitObjCImplementationDecl(ObjCImplementationDecl *D);
157     Decl *VisitObjCPropertyDecl(ObjCPropertyDecl *D);
158     Decl *VisitObjCPropertyImplDecl(ObjCPropertyImplDecl *D);
159     Decl *VisitTemplateTypeParmDecl(TemplateTypeParmDecl *D);
160     Decl *VisitNonTypeTemplateParmDecl(NonTypeTemplateParmDecl *D);
161     Decl *VisitTemplateTemplateParmDecl(TemplateTemplateParmDecl *D);
162     Decl *VisitClassTemplateDecl(ClassTemplateDecl *D);
163     Decl *VisitClassTemplateSpecializationDecl(
164                                             ClassTemplateSpecializationDecl *D);
165     Decl *VisitVarTemplateDecl(VarTemplateDecl *D);
166     Decl *VisitVarTemplateSpecializationDecl(VarTemplateSpecializationDecl *D);
167 
168     // Importing statements
169     Stmt *VisitStmt(Stmt *S);
170 
171     // Importing expressions
172     Expr *VisitExpr(Expr *E);
173     Expr *VisitDeclRefExpr(DeclRefExpr *E);
174     Expr *VisitIntegerLiteral(IntegerLiteral *E);
175     Expr *VisitCharacterLiteral(CharacterLiteral *E);
176     Expr *VisitParenExpr(ParenExpr *E);
177     Expr *VisitUnaryOperator(UnaryOperator *E);
178     Expr *VisitUnaryExprOrTypeTraitExpr(UnaryExprOrTypeTraitExpr *E);
179     Expr *VisitBinaryOperator(BinaryOperator *E);
180     Expr *VisitCompoundAssignOperator(CompoundAssignOperator *E);
181     Expr *VisitImplicitCastExpr(ImplicitCastExpr *E);
182     Expr *VisitCStyleCastExpr(CStyleCastExpr *E);
183   };
184 }
185 using namespace clang;
186 
187 //----------------------------------------------------------------------------
188 // Structural Equivalence
189 //----------------------------------------------------------------------------
190 
191 namespace {
192   struct StructuralEquivalenceContext {
193     /// \brief AST contexts for which we are checking structural equivalence.
194     ASTContext &C1, &C2;
195 
196     /// \brief The set of "tentative" equivalences between two canonical
197     /// declarations, mapping from a declaration in the first context to the
198     /// declaration in the second context that we believe to be equivalent.
199     llvm::DenseMap<Decl *, Decl *> TentativeEquivalences;
200 
201     /// \brief Queue of declarations in the first context whose equivalence
202     /// with a declaration in the second context still needs to be verified.
203     std::deque<Decl *> DeclsToCheck;
204 
205     /// \brief Declaration (from, to) pairs that are known not to be equivalent
206     /// (which we have already complained about).
207     llvm::DenseSet<std::pair<Decl *, Decl *> > &NonEquivalentDecls;
208 
209     /// \brief Whether we're being strict about the spelling of types when
210     /// unifying two types.
211     bool StrictTypeSpelling;
212 
213     /// \brief Whether to complain about failures.
214     bool Complain;
215 
216     /// \brief \c true if the last diagnostic came from C2.
217     bool LastDiagFromC2;
218 
219     StructuralEquivalenceContext(ASTContext &C1, ASTContext &C2,
220                llvm::DenseSet<std::pair<Decl *, Decl *> > &NonEquivalentDecls,
221                                  bool StrictTypeSpelling = false,
222                                  bool Complain = true)
223       : C1(C1), C2(C2), NonEquivalentDecls(NonEquivalentDecls),
224         StrictTypeSpelling(StrictTypeSpelling), Complain(Complain),
225         LastDiagFromC2(false) {}
226 
227     /// \brief Determine whether the two declarations are structurally
228     /// equivalent.
229     bool IsStructurallyEquivalent(Decl *D1, Decl *D2);
230 
231     /// \brief Determine whether the two types are structurally equivalent.
232     bool IsStructurallyEquivalent(QualType T1, QualType T2);
233 
234   private:
235     /// \brief Finish checking all of the structural equivalences.
236     ///
237     /// \returns true if an error occurred, false otherwise.
238     bool Finish();
239 
240   public:
241     DiagnosticBuilder Diag1(SourceLocation Loc, unsigned DiagID) {
242       assert(Complain && "Not allowed to complain");
243       if (LastDiagFromC2)
244         C1.getDiagnostics().notePriorDiagnosticFrom(C2.getDiagnostics());
245       LastDiagFromC2 = false;
246       return C1.getDiagnostics().Report(Loc, DiagID);
247     }
248 
249     DiagnosticBuilder Diag2(SourceLocation Loc, unsigned DiagID) {
250       assert(Complain && "Not allowed to complain");
251       if (!LastDiagFromC2)
252         C2.getDiagnostics().notePriorDiagnosticFrom(C1.getDiagnostics());
253       LastDiagFromC2 = true;
254       return C2.getDiagnostics().Report(Loc, DiagID);
255     }
256   };
257 }
258 
259 static bool IsStructurallyEquivalent(StructuralEquivalenceContext &Context,
260                                      QualType T1, QualType T2);
261 static bool IsStructurallyEquivalent(StructuralEquivalenceContext &Context,
262                                      Decl *D1, Decl *D2);
263 
264 /// \brief Determine structural equivalence of two expressions.
265 static bool IsStructurallyEquivalent(StructuralEquivalenceContext &Context,
266                                      Expr *E1, Expr *E2) {
267   if (!E1 || !E2)
268     return E1 == E2;
269 
270   // FIXME: Actually perform a structural comparison!
271   return true;
272 }
273 
274 /// \brief Determine whether two identifiers are equivalent.
275 static bool IsStructurallyEquivalent(const IdentifierInfo *Name1,
276                                      const IdentifierInfo *Name2) {
277   if (!Name1 || !Name2)
278     return Name1 == Name2;
279 
280   return Name1->getName() == Name2->getName();
281 }
282 
283 /// \brief Determine whether two nested-name-specifiers are equivalent.
284 static bool IsStructurallyEquivalent(StructuralEquivalenceContext &Context,
285                                      NestedNameSpecifier *NNS1,
286                                      NestedNameSpecifier *NNS2) {
287   // FIXME: Implement!
288   return true;
289 }
290 
291 /// \brief Determine whether two template arguments are equivalent.
292 static bool IsStructurallyEquivalent(StructuralEquivalenceContext &Context,
293                                      const TemplateArgument &Arg1,
294                                      const TemplateArgument &Arg2) {
295   if (Arg1.getKind() != Arg2.getKind())
296     return false;
297 
298   switch (Arg1.getKind()) {
299   case TemplateArgument::Null:
300     return true;
301 
302   case TemplateArgument::Type:
303     return Context.IsStructurallyEquivalent(Arg1.getAsType(), Arg2.getAsType());
304 
305   case TemplateArgument::Integral:
306     if (!Context.IsStructurallyEquivalent(Arg1.getIntegralType(),
307                                           Arg2.getIntegralType()))
308       return false;
309 
310     return llvm::APSInt::isSameValue(Arg1.getAsIntegral(), Arg2.getAsIntegral());
311 
312   case TemplateArgument::Declaration:
313     return Context.IsStructurallyEquivalent(Arg1.getAsDecl(), Arg2.getAsDecl());
314 
315   case TemplateArgument::NullPtr:
316     return true; // FIXME: Is this correct?
317 
318   case TemplateArgument::Template:
319     return IsStructurallyEquivalent(Context,
320                                     Arg1.getAsTemplate(),
321                                     Arg2.getAsTemplate());
322 
323   case TemplateArgument::TemplateExpansion:
324     return IsStructurallyEquivalent(Context,
325                                     Arg1.getAsTemplateOrTemplatePattern(),
326                                     Arg2.getAsTemplateOrTemplatePattern());
327 
328   case TemplateArgument::Expression:
329     return IsStructurallyEquivalent(Context,
330                                     Arg1.getAsExpr(), Arg2.getAsExpr());
331 
332   case TemplateArgument::Pack:
333     if (Arg1.pack_size() != Arg2.pack_size())
334       return false;
335 
336     for (unsigned I = 0, N = Arg1.pack_size(); I != N; ++I)
337       if (!IsStructurallyEquivalent(Context,
338                                     Arg1.pack_begin()[I],
339                                     Arg2.pack_begin()[I]))
340         return false;
341 
342     return true;
343   }
344 
345   llvm_unreachable("Invalid template argument kind");
346 }
347 
348 /// \brief Determine structural equivalence for the common part of array
349 /// types.
350 static bool IsArrayStructurallyEquivalent(StructuralEquivalenceContext &Context,
351                                           const ArrayType *Array1,
352                                           const ArrayType *Array2) {
353   if (!IsStructurallyEquivalent(Context,
354                                 Array1->getElementType(),
355                                 Array2->getElementType()))
356     return false;
357   if (Array1->getSizeModifier() != Array2->getSizeModifier())
358     return false;
359   if (Array1->getIndexTypeQualifiers() != Array2->getIndexTypeQualifiers())
360     return false;
361 
362   return true;
363 }
364 
365 /// \brief Determine structural equivalence of two types.
366 static bool IsStructurallyEquivalent(StructuralEquivalenceContext &Context,
367                                      QualType T1, QualType T2) {
368   if (T1.isNull() || T2.isNull())
369     return T1.isNull() && T2.isNull();
370 
371   if (!Context.StrictTypeSpelling) {
372     // We aren't being strict about token-to-token equivalence of types,
373     // so map down to the canonical type.
374     T1 = Context.C1.getCanonicalType(T1);
375     T2 = Context.C2.getCanonicalType(T2);
376   }
377 
378   if (T1.getQualifiers() != T2.getQualifiers())
379     return false;
380 
381   Type::TypeClass TC = T1->getTypeClass();
382 
383   if (T1->getTypeClass() != T2->getTypeClass()) {
384     // Compare function types with prototypes vs. without prototypes as if
385     // both did not have prototypes.
386     if (T1->getTypeClass() == Type::FunctionProto &&
387         T2->getTypeClass() == Type::FunctionNoProto)
388       TC = Type::FunctionNoProto;
389     else if (T1->getTypeClass() == Type::FunctionNoProto &&
390              T2->getTypeClass() == Type::FunctionProto)
391       TC = Type::FunctionNoProto;
392     else
393       return false;
394   }
395 
396   switch (TC) {
397   case Type::Builtin:
398     // FIXME: Deal with Char_S/Char_U.
399     if (cast<BuiltinType>(T1)->getKind() != cast<BuiltinType>(T2)->getKind())
400       return false;
401     break;
402 
403   case Type::Complex:
404     if (!IsStructurallyEquivalent(Context,
405                                   cast<ComplexType>(T1)->getElementType(),
406                                   cast<ComplexType>(T2)->getElementType()))
407       return false;
408     break;
409 
410   case Type::Adjusted:
411   case Type::Decayed:
412     if (!IsStructurallyEquivalent(Context,
413                                   cast<AdjustedType>(T1)->getOriginalType(),
414                                   cast<AdjustedType>(T2)->getOriginalType()))
415       return false;
416     break;
417 
418   case Type::Pointer:
419     if (!IsStructurallyEquivalent(Context,
420                                   cast<PointerType>(T1)->getPointeeType(),
421                                   cast<PointerType>(T2)->getPointeeType()))
422       return false;
423     break;
424 
425   case Type::BlockPointer:
426     if (!IsStructurallyEquivalent(Context,
427                                   cast<BlockPointerType>(T1)->getPointeeType(),
428                                   cast<BlockPointerType>(T2)->getPointeeType()))
429       return false;
430     break;
431 
432   case Type::LValueReference:
433   case Type::RValueReference: {
434     const ReferenceType *Ref1 = cast<ReferenceType>(T1);
435     const ReferenceType *Ref2 = cast<ReferenceType>(T2);
436     if (Ref1->isSpelledAsLValue() != Ref2->isSpelledAsLValue())
437       return false;
438     if (Ref1->isInnerRef() != Ref2->isInnerRef())
439       return false;
440     if (!IsStructurallyEquivalent(Context,
441                                   Ref1->getPointeeTypeAsWritten(),
442                                   Ref2->getPointeeTypeAsWritten()))
443       return false;
444     break;
445   }
446 
447   case Type::MemberPointer: {
448     const MemberPointerType *MemPtr1 = cast<MemberPointerType>(T1);
449     const MemberPointerType *MemPtr2 = cast<MemberPointerType>(T2);
450     if (!IsStructurallyEquivalent(Context,
451                                   MemPtr1->getPointeeType(),
452                                   MemPtr2->getPointeeType()))
453       return false;
454     if (!IsStructurallyEquivalent(Context,
455                                   QualType(MemPtr1->getClass(), 0),
456                                   QualType(MemPtr2->getClass(), 0)))
457       return false;
458     break;
459   }
460 
461   case Type::ConstantArray: {
462     const ConstantArrayType *Array1 = cast<ConstantArrayType>(T1);
463     const ConstantArrayType *Array2 = cast<ConstantArrayType>(T2);
464     if (!llvm::APInt::isSameValue(Array1->getSize(), Array2->getSize()))
465       return false;
466 
467     if (!IsArrayStructurallyEquivalent(Context, Array1, Array2))
468       return false;
469     break;
470   }
471 
472   case Type::IncompleteArray:
473     if (!IsArrayStructurallyEquivalent(Context,
474                                        cast<ArrayType>(T1),
475                                        cast<ArrayType>(T2)))
476       return false;
477     break;
478 
479   case Type::VariableArray: {
480     const VariableArrayType *Array1 = cast<VariableArrayType>(T1);
481     const VariableArrayType *Array2 = cast<VariableArrayType>(T2);
482     if (!IsStructurallyEquivalent(Context,
483                                   Array1->getSizeExpr(), Array2->getSizeExpr()))
484       return false;
485 
486     if (!IsArrayStructurallyEquivalent(Context, Array1, Array2))
487       return false;
488 
489     break;
490   }
491 
492   case Type::DependentSizedArray: {
493     const DependentSizedArrayType *Array1 = cast<DependentSizedArrayType>(T1);
494     const DependentSizedArrayType *Array2 = cast<DependentSizedArrayType>(T2);
495     if (!IsStructurallyEquivalent(Context,
496                                   Array1->getSizeExpr(), Array2->getSizeExpr()))
497       return false;
498 
499     if (!IsArrayStructurallyEquivalent(Context, Array1, Array2))
500       return false;
501 
502     break;
503   }
504 
505   case Type::DependentSizedExtVector: {
506     const DependentSizedExtVectorType *Vec1
507       = cast<DependentSizedExtVectorType>(T1);
508     const DependentSizedExtVectorType *Vec2
509       = cast<DependentSizedExtVectorType>(T2);
510     if (!IsStructurallyEquivalent(Context,
511                                   Vec1->getSizeExpr(), Vec2->getSizeExpr()))
512       return false;
513     if (!IsStructurallyEquivalent(Context,
514                                   Vec1->getElementType(),
515                                   Vec2->getElementType()))
516       return false;
517     break;
518   }
519 
520   case Type::Vector:
521   case Type::ExtVector: {
522     const VectorType *Vec1 = cast<VectorType>(T1);
523     const VectorType *Vec2 = cast<VectorType>(T2);
524     if (!IsStructurallyEquivalent(Context,
525                                   Vec1->getElementType(),
526                                   Vec2->getElementType()))
527       return false;
528     if (Vec1->getNumElements() != Vec2->getNumElements())
529       return false;
530     if (Vec1->getVectorKind() != Vec2->getVectorKind())
531       return false;
532     break;
533   }
534 
535   case Type::FunctionProto: {
536     const FunctionProtoType *Proto1 = cast<FunctionProtoType>(T1);
537     const FunctionProtoType *Proto2 = cast<FunctionProtoType>(T2);
538     if (Proto1->getNumParams() != Proto2->getNumParams())
539       return false;
540     for (unsigned I = 0, N = Proto1->getNumParams(); I != N; ++I) {
541       if (!IsStructurallyEquivalent(Context, Proto1->getParamType(I),
542                                     Proto2->getParamType(I)))
543         return false;
544     }
545     if (Proto1->isVariadic() != Proto2->isVariadic())
546       return false;
547     if (Proto1->getExceptionSpecType() != Proto2->getExceptionSpecType())
548       return false;
549     if (Proto1->getExceptionSpecType() == EST_Dynamic) {
550       if (Proto1->getNumExceptions() != Proto2->getNumExceptions())
551         return false;
552       for (unsigned I = 0, N = Proto1->getNumExceptions(); I != N; ++I) {
553         if (!IsStructurallyEquivalent(Context,
554                                       Proto1->getExceptionType(I),
555                                       Proto2->getExceptionType(I)))
556           return false;
557       }
558     } else if (Proto1->getExceptionSpecType() == EST_ComputedNoexcept) {
559       if (!IsStructurallyEquivalent(Context,
560                                     Proto1->getNoexceptExpr(),
561                                     Proto2->getNoexceptExpr()))
562         return false;
563     }
564     if (Proto1->getTypeQuals() != Proto2->getTypeQuals())
565       return false;
566 
567     // Fall through to check the bits common with FunctionNoProtoType.
568   }
569 
570   case Type::FunctionNoProto: {
571     const FunctionType *Function1 = cast<FunctionType>(T1);
572     const FunctionType *Function2 = cast<FunctionType>(T2);
573     if (!IsStructurallyEquivalent(Context, Function1->getReturnType(),
574                                   Function2->getReturnType()))
575       return false;
576       if (Function1->getExtInfo() != Function2->getExtInfo())
577         return false;
578     break;
579   }
580 
581   case Type::UnresolvedUsing:
582     if (!IsStructurallyEquivalent(Context,
583                                   cast<UnresolvedUsingType>(T1)->getDecl(),
584                                   cast<UnresolvedUsingType>(T2)->getDecl()))
585       return false;
586 
587     break;
588 
589   case Type::Attributed:
590     if (!IsStructurallyEquivalent(Context,
591                                   cast<AttributedType>(T1)->getModifiedType(),
592                                   cast<AttributedType>(T2)->getModifiedType()))
593       return false;
594     if (!IsStructurallyEquivalent(Context,
595                                 cast<AttributedType>(T1)->getEquivalentType(),
596                                 cast<AttributedType>(T2)->getEquivalentType()))
597       return false;
598     break;
599 
600   case Type::Paren:
601     if (!IsStructurallyEquivalent(Context,
602                                   cast<ParenType>(T1)->getInnerType(),
603                                   cast<ParenType>(T2)->getInnerType()))
604       return false;
605     break;
606 
607   case Type::Typedef:
608     if (!IsStructurallyEquivalent(Context,
609                                   cast<TypedefType>(T1)->getDecl(),
610                                   cast<TypedefType>(T2)->getDecl()))
611       return false;
612     break;
613 
614   case Type::TypeOfExpr:
615     if (!IsStructurallyEquivalent(Context,
616                                 cast<TypeOfExprType>(T1)->getUnderlyingExpr(),
617                                 cast<TypeOfExprType>(T2)->getUnderlyingExpr()))
618       return false;
619     break;
620 
621   case Type::TypeOf:
622     if (!IsStructurallyEquivalent(Context,
623                                   cast<TypeOfType>(T1)->getUnderlyingType(),
624                                   cast<TypeOfType>(T2)->getUnderlyingType()))
625       return false;
626     break;
627 
628   case Type::UnaryTransform:
629     if (!IsStructurallyEquivalent(Context,
630                              cast<UnaryTransformType>(T1)->getUnderlyingType(),
631                              cast<UnaryTransformType>(T1)->getUnderlyingType()))
632       return false;
633     break;
634 
635   case Type::Decltype:
636     if (!IsStructurallyEquivalent(Context,
637                                   cast<DecltypeType>(T1)->getUnderlyingExpr(),
638                                   cast<DecltypeType>(T2)->getUnderlyingExpr()))
639       return false;
640     break;
641 
642   case Type::Auto:
643     if (!IsStructurallyEquivalent(Context,
644                                   cast<AutoType>(T1)->getDeducedType(),
645                                   cast<AutoType>(T2)->getDeducedType()))
646       return false;
647     break;
648 
649   case Type::Record:
650   case Type::Enum:
651     if (!IsStructurallyEquivalent(Context,
652                                   cast<TagType>(T1)->getDecl(),
653                                   cast<TagType>(T2)->getDecl()))
654       return false;
655     break;
656 
657   case Type::TemplateTypeParm: {
658     const TemplateTypeParmType *Parm1 = cast<TemplateTypeParmType>(T1);
659     const TemplateTypeParmType *Parm2 = cast<TemplateTypeParmType>(T2);
660     if (Parm1->getDepth() != Parm2->getDepth())
661       return false;
662     if (Parm1->getIndex() != Parm2->getIndex())
663       return false;
664     if (Parm1->isParameterPack() != Parm2->isParameterPack())
665       return false;
666 
667     // Names of template type parameters are never significant.
668     break;
669   }
670 
671   case Type::SubstTemplateTypeParm: {
672     const SubstTemplateTypeParmType *Subst1
673       = cast<SubstTemplateTypeParmType>(T1);
674     const SubstTemplateTypeParmType *Subst2
675       = cast<SubstTemplateTypeParmType>(T2);
676     if (!IsStructurallyEquivalent(Context,
677                                   QualType(Subst1->getReplacedParameter(), 0),
678                                   QualType(Subst2->getReplacedParameter(), 0)))
679       return false;
680     if (!IsStructurallyEquivalent(Context,
681                                   Subst1->getReplacementType(),
682                                   Subst2->getReplacementType()))
683       return false;
684     break;
685   }
686 
687   case Type::SubstTemplateTypeParmPack: {
688     const SubstTemplateTypeParmPackType *Subst1
689       = cast<SubstTemplateTypeParmPackType>(T1);
690     const SubstTemplateTypeParmPackType *Subst2
691       = cast<SubstTemplateTypeParmPackType>(T2);
692     if (!IsStructurallyEquivalent(Context,
693                                   QualType(Subst1->getReplacedParameter(), 0),
694                                   QualType(Subst2->getReplacedParameter(), 0)))
695       return false;
696     if (!IsStructurallyEquivalent(Context,
697                                   Subst1->getArgumentPack(),
698                                   Subst2->getArgumentPack()))
699       return false;
700     break;
701   }
702   case Type::TemplateSpecialization: {
703     const TemplateSpecializationType *Spec1
704       = cast<TemplateSpecializationType>(T1);
705     const TemplateSpecializationType *Spec2
706       = cast<TemplateSpecializationType>(T2);
707     if (!IsStructurallyEquivalent(Context,
708                                   Spec1->getTemplateName(),
709                                   Spec2->getTemplateName()))
710       return false;
711     if (Spec1->getNumArgs() != Spec2->getNumArgs())
712       return false;
713     for (unsigned I = 0, N = Spec1->getNumArgs(); I != N; ++I) {
714       if (!IsStructurallyEquivalent(Context,
715                                     Spec1->getArg(I), Spec2->getArg(I)))
716         return false;
717     }
718     break;
719   }
720 
721   case Type::Elaborated: {
722     const ElaboratedType *Elab1 = cast<ElaboratedType>(T1);
723     const ElaboratedType *Elab2 = cast<ElaboratedType>(T2);
724     // CHECKME: what if a keyword is ETK_None or ETK_typename ?
725     if (Elab1->getKeyword() != Elab2->getKeyword())
726       return false;
727     if (!IsStructurallyEquivalent(Context,
728                                   Elab1->getQualifier(),
729                                   Elab2->getQualifier()))
730       return false;
731     if (!IsStructurallyEquivalent(Context,
732                                   Elab1->getNamedType(),
733                                   Elab2->getNamedType()))
734       return false;
735     break;
736   }
737 
738   case Type::InjectedClassName: {
739     const InjectedClassNameType *Inj1 = cast<InjectedClassNameType>(T1);
740     const InjectedClassNameType *Inj2 = cast<InjectedClassNameType>(T2);
741     if (!IsStructurallyEquivalent(Context,
742                                   Inj1->getInjectedSpecializationType(),
743                                   Inj2->getInjectedSpecializationType()))
744       return false;
745     break;
746   }
747 
748   case Type::DependentName: {
749     const DependentNameType *Typename1 = cast<DependentNameType>(T1);
750     const DependentNameType *Typename2 = cast<DependentNameType>(T2);
751     if (!IsStructurallyEquivalent(Context,
752                                   Typename1->getQualifier(),
753                                   Typename2->getQualifier()))
754       return false;
755     if (!IsStructurallyEquivalent(Typename1->getIdentifier(),
756                                   Typename2->getIdentifier()))
757       return false;
758 
759     break;
760   }
761 
762   case Type::DependentTemplateSpecialization: {
763     const DependentTemplateSpecializationType *Spec1 =
764       cast<DependentTemplateSpecializationType>(T1);
765     const DependentTemplateSpecializationType *Spec2 =
766       cast<DependentTemplateSpecializationType>(T2);
767     if (!IsStructurallyEquivalent(Context,
768                                   Spec1->getQualifier(),
769                                   Spec2->getQualifier()))
770       return false;
771     if (!IsStructurallyEquivalent(Spec1->getIdentifier(),
772                                   Spec2->getIdentifier()))
773       return false;
774     if (Spec1->getNumArgs() != Spec2->getNumArgs())
775       return false;
776     for (unsigned I = 0, N = Spec1->getNumArgs(); I != N; ++I) {
777       if (!IsStructurallyEquivalent(Context,
778                                     Spec1->getArg(I), Spec2->getArg(I)))
779         return false;
780     }
781     break;
782   }
783 
784   case Type::PackExpansion:
785     if (!IsStructurallyEquivalent(Context,
786                                   cast<PackExpansionType>(T1)->getPattern(),
787                                   cast<PackExpansionType>(T2)->getPattern()))
788       return false;
789     break;
790 
791   case Type::ObjCInterface: {
792     const ObjCInterfaceType *Iface1 = cast<ObjCInterfaceType>(T1);
793     const ObjCInterfaceType *Iface2 = cast<ObjCInterfaceType>(T2);
794     if (!IsStructurallyEquivalent(Context,
795                                   Iface1->getDecl(), Iface2->getDecl()))
796       return false;
797     break;
798   }
799 
800   case Type::ObjCObject: {
801     const ObjCObjectType *Obj1 = cast<ObjCObjectType>(T1);
802     const ObjCObjectType *Obj2 = cast<ObjCObjectType>(T2);
803     if (!IsStructurallyEquivalent(Context,
804                                   Obj1->getBaseType(),
805                                   Obj2->getBaseType()))
806       return false;
807     if (Obj1->getNumProtocols() != Obj2->getNumProtocols())
808       return false;
809     for (unsigned I = 0, N = Obj1->getNumProtocols(); I != N; ++I) {
810       if (!IsStructurallyEquivalent(Context,
811                                     Obj1->getProtocol(I),
812                                     Obj2->getProtocol(I)))
813         return false;
814     }
815     break;
816   }
817 
818   case Type::ObjCObjectPointer: {
819     const ObjCObjectPointerType *Ptr1 = cast<ObjCObjectPointerType>(T1);
820     const ObjCObjectPointerType *Ptr2 = cast<ObjCObjectPointerType>(T2);
821     if (!IsStructurallyEquivalent(Context,
822                                   Ptr1->getPointeeType(),
823                                   Ptr2->getPointeeType()))
824       return false;
825     break;
826   }
827 
828   case Type::Atomic: {
829     if (!IsStructurallyEquivalent(Context,
830                                   cast<AtomicType>(T1)->getValueType(),
831                                   cast<AtomicType>(T2)->getValueType()))
832       return false;
833     break;
834   }
835 
836   } // end switch
837 
838   return true;
839 }
840 
841 /// \brief Determine structural equivalence of two fields.
842 static bool IsStructurallyEquivalent(StructuralEquivalenceContext &Context,
843                                      FieldDecl *Field1, FieldDecl *Field2) {
844   RecordDecl *Owner2 = cast<RecordDecl>(Field2->getDeclContext());
845 
846   // For anonymous structs/unions, match up the anonymous struct/union type
847   // declarations directly, so that we don't go off searching for anonymous
848   // types
849   if (Field1->isAnonymousStructOrUnion() &&
850       Field2->isAnonymousStructOrUnion()) {
851     RecordDecl *D1 = Field1->getType()->castAs<RecordType>()->getDecl();
852     RecordDecl *D2 = Field2->getType()->castAs<RecordType>()->getDecl();
853     return IsStructurallyEquivalent(Context, D1, D2);
854   }
855 
856   // Check for equivalent field names.
857   IdentifierInfo *Name1 = Field1->getIdentifier();
858   IdentifierInfo *Name2 = Field2->getIdentifier();
859   if (!::IsStructurallyEquivalent(Name1, Name2))
860     return false;
861 
862   if (!IsStructurallyEquivalent(Context,
863                                 Field1->getType(), Field2->getType())) {
864     if (Context.Complain) {
865       Context.Diag2(Owner2->getLocation(), diag::warn_odr_tag_type_inconsistent)
866         << Context.C2.getTypeDeclType(Owner2);
867       Context.Diag2(Field2->getLocation(), diag::note_odr_field)
868         << Field2->getDeclName() << Field2->getType();
869       Context.Diag1(Field1->getLocation(), diag::note_odr_field)
870         << Field1->getDeclName() << Field1->getType();
871     }
872     return false;
873   }
874 
875   if (Field1->isBitField() != Field2->isBitField()) {
876     if (Context.Complain) {
877       Context.Diag2(Owner2->getLocation(), diag::warn_odr_tag_type_inconsistent)
878         << Context.C2.getTypeDeclType(Owner2);
879       if (Field1->isBitField()) {
880         Context.Diag1(Field1->getLocation(), diag::note_odr_bit_field)
881         << Field1->getDeclName() << Field1->getType()
882         << Field1->getBitWidthValue(Context.C1);
883         Context.Diag2(Field2->getLocation(), diag::note_odr_not_bit_field)
884         << Field2->getDeclName();
885       } else {
886         Context.Diag2(Field2->getLocation(), diag::note_odr_bit_field)
887         << Field2->getDeclName() << Field2->getType()
888         << Field2->getBitWidthValue(Context.C2);
889         Context.Diag1(Field1->getLocation(), diag::note_odr_not_bit_field)
890         << Field1->getDeclName();
891       }
892     }
893     return false;
894   }
895 
896   if (Field1->isBitField()) {
897     // Make sure that the bit-fields are the same length.
898     unsigned Bits1 = Field1->getBitWidthValue(Context.C1);
899     unsigned Bits2 = Field2->getBitWidthValue(Context.C2);
900 
901     if (Bits1 != Bits2) {
902       if (Context.Complain) {
903         Context.Diag2(Owner2->getLocation(), diag::warn_odr_tag_type_inconsistent)
904           << Context.C2.getTypeDeclType(Owner2);
905         Context.Diag2(Field2->getLocation(), diag::note_odr_bit_field)
906           << Field2->getDeclName() << Field2->getType() << Bits2;
907         Context.Diag1(Field1->getLocation(), diag::note_odr_bit_field)
908           << Field1->getDeclName() << Field1->getType() << Bits1;
909       }
910       return false;
911     }
912   }
913 
914   return true;
915 }
916 
917 /// \brief Find the index of the given anonymous struct/union within its
918 /// context.
919 ///
920 /// \returns Returns the index of this anonymous struct/union in its context,
921 /// including the next assigned index (if none of them match). Returns an
922 /// empty option if the context is not a record, i.e.. if the anonymous
923 /// struct/union is at namespace or block scope.
924 static Optional<unsigned> findAnonymousStructOrUnionIndex(RecordDecl *Anon) {
925   ASTContext &Context = Anon->getASTContext();
926   QualType AnonTy = Context.getRecordType(Anon);
927 
928   RecordDecl *Owner = dyn_cast<RecordDecl>(Anon->getDeclContext());
929   if (!Owner)
930     return None;
931 
932   unsigned Index = 0;
933   for (const auto *D : Owner->noload_decls()) {
934     const auto *F = dyn_cast<FieldDecl>(D);
935     if (!F || !F->isAnonymousStructOrUnion())
936       continue;
937 
938     if (Context.hasSameType(F->getType(), AnonTy))
939       break;
940 
941     ++Index;
942   }
943 
944   return Index;
945 }
946 
947 /// \brief Determine structural equivalence of two records.
948 static bool IsStructurallyEquivalent(StructuralEquivalenceContext &Context,
949                                      RecordDecl *D1, RecordDecl *D2) {
950   if (D1->isUnion() != D2->isUnion()) {
951     if (Context.Complain) {
952       Context.Diag2(D2->getLocation(), diag::warn_odr_tag_type_inconsistent)
953         << Context.C2.getTypeDeclType(D2);
954       Context.Diag1(D1->getLocation(), diag::note_odr_tag_kind_here)
955         << D1->getDeclName() << (unsigned)D1->getTagKind();
956     }
957     return false;
958   }
959 
960   if (D1->isAnonymousStructOrUnion() && D2->isAnonymousStructOrUnion()) {
961     // If both anonymous structs/unions are in a record context, make sure
962     // they occur in the same location in the context records.
963     if (Optional<unsigned> Index1 = findAnonymousStructOrUnionIndex(D1)) {
964       if (Optional<unsigned> Index2 = findAnonymousStructOrUnionIndex(D2)) {
965         if (*Index1 != *Index2)
966           return false;
967       }
968     }
969   }
970 
971   // If both declarations are class template specializations, we know
972   // the ODR applies, so check the template and template arguments.
973   ClassTemplateSpecializationDecl *Spec1
974     = dyn_cast<ClassTemplateSpecializationDecl>(D1);
975   ClassTemplateSpecializationDecl *Spec2
976     = dyn_cast<ClassTemplateSpecializationDecl>(D2);
977   if (Spec1 && Spec2) {
978     // Check that the specialized templates are the same.
979     if (!IsStructurallyEquivalent(Context, Spec1->getSpecializedTemplate(),
980                                   Spec2->getSpecializedTemplate()))
981       return false;
982 
983     // Check that the template arguments are the same.
984     if (Spec1->getTemplateArgs().size() != Spec2->getTemplateArgs().size())
985       return false;
986 
987     for (unsigned I = 0, N = Spec1->getTemplateArgs().size(); I != N; ++I)
988       if (!IsStructurallyEquivalent(Context,
989                                     Spec1->getTemplateArgs().get(I),
990                                     Spec2->getTemplateArgs().get(I)))
991         return false;
992   }
993   // If one is a class template specialization and the other is not, these
994   // structures are different.
995   else if (Spec1 || Spec2)
996     return false;
997 
998   // Compare the definitions of these two records. If either or both are
999   // incomplete, we assume that they are equivalent.
1000   D1 = D1->getDefinition();
1001   D2 = D2->getDefinition();
1002   if (!D1 || !D2)
1003     return true;
1004 
1005   if (CXXRecordDecl *D1CXX = dyn_cast<CXXRecordDecl>(D1)) {
1006     if (CXXRecordDecl *D2CXX = dyn_cast<CXXRecordDecl>(D2)) {
1007       if (D1CXX->getNumBases() != D2CXX->getNumBases()) {
1008         if (Context.Complain) {
1009           Context.Diag2(D2->getLocation(), diag::warn_odr_tag_type_inconsistent)
1010             << Context.C2.getTypeDeclType(D2);
1011           Context.Diag2(D2->getLocation(), diag::note_odr_number_of_bases)
1012             << D2CXX->getNumBases();
1013           Context.Diag1(D1->getLocation(), diag::note_odr_number_of_bases)
1014             << D1CXX->getNumBases();
1015         }
1016         return false;
1017       }
1018 
1019       // Check the base classes.
1020       for (CXXRecordDecl::base_class_iterator Base1 = D1CXX->bases_begin(),
1021                                            BaseEnd1 = D1CXX->bases_end(),
1022                                                 Base2 = D2CXX->bases_begin();
1023            Base1 != BaseEnd1;
1024            ++Base1, ++Base2) {
1025         if (!IsStructurallyEquivalent(Context,
1026                                       Base1->getType(), Base2->getType())) {
1027           if (Context.Complain) {
1028             Context.Diag2(D2->getLocation(), diag::warn_odr_tag_type_inconsistent)
1029               << Context.C2.getTypeDeclType(D2);
1030             Context.Diag2(Base2->getLocStart(), diag::note_odr_base)
1031               << Base2->getType()
1032               << Base2->getSourceRange();
1033             Context.Diag1(Base1->getLocStart(), diag::note_odr_base)
1034               << Base1->getType()
1035               << Base1->getSourceRange();
1036           }
1037           return false;
1038         }
1039 
1040         // Check virtual vs. non-virtual inheritance mismatch.
1041         if (Base1->isVirtual() != Base2->isVirtual()) {
1042           if (Context.Complain) {
1043             Context.Diag2(D2->getLocation(), diag::warn_odr_tag_type_inconsistent)
1044               << Context.C2.getTypeDeclType(D2);
1045             Context.Diag2(Base2->getLocStart(),
1046                           diag::note_odr_virtual_base)
1047               << Base2->isVirtual() << Base2->getSourceRange();
1048             Context.Diag1(Base1->getLocStart(), diag::note_odr_base)
1049               << Base1->isVirtual()
1050               << Base1->getSourceRange();
1051           }
1052           return false;
1053         }
1054       }
1055     } else if (D1CXX->getNumBases() > 0) {
1056       if (Context.Complain) {
1057         Context.Diag2(D2->getLocation(), diag::warn_odr_tag_type_inconsistent)
1058           << Context.C2.getTypeDeclType(D2);
1059         const CXXBaseSpecifier *Base1 = D1CXX->bases_begin();
1060         Context.Diag1(Base1->getLocStart(), diag::note_odr_base)
1061           << Base1->getType()
1062           << Base1->getSourceRange();
1063         Context.Diag2(D2->getLocation(), diag::note_odr_missing_base);
1064       }
1065       return false;
1066     }
1067   }
1068 
1069   // Check the fields for consistency.
1070   RecordDecl::field_iterator Field2 = D2->field_begin(),
1071                              Field2End = D2->field_end();
1072   for (RecordDecl::field_iterator Field1 = D1->field_begin(),
1073                                   Field1End = D1->field_end();
1074        Field1 != Field1End;
1075        ++Field1, ++Field2) {
1076     if (Field2 == Field2End) {
1077       if (Context.Complain) {
1078         Context.Diag2(D2->getLocation(), diag::warn_odr_tag_type_inconsistent)
1079           << Context.C2.getTypeDeclType(D2);
1080         Context.Diag1(Field1->getLocation(), diag::note_odr_field)
1081           << Field1->getDeclName() << Field1->getType();
1082         Context.Diag2(D2->getLocation(), diag::note_odr_missing_field);
1083       }
1084       return false;
1085     }
1086 
1087     if (!IsStructurallyEquivalent(Context, *Field1, *Field2))
1088       return false;
1089   }
1090 
1091   if (Field2 != Field2End) {
1092     if (Context.Complain) {
1093       Context.Diag2(D2->getLocation(), diag::warn_odr_tag_type_inconsistent)
1094         << Context.C2.getTypeDeclType(D2);
1095       Context.Diag2(Field2->getLocation(), diag::note_odr_field)
1096         << Field2->getDeclName() << Field2->getType();
1097       Context.Diag1(D1->getLocation(), diag::note_odr_missing_field);
1098     }
1099     return false;
1100   }
1101 
1102   return true;
1103 }
1104 
1105 /// \brief Determine structural equivalence of two enums.
1106 static bool IsStructurallyEquivalent(StructuralEquivalenceContext &Context,
1107                                      EnumDecl *D1, EnumDecl *D2) {
1108   EnumDecl::enumerator_iterator EC2 = D2->enumerator_begin(),
1109                              EC2End = D2->enumerator_end();
1110   for (EnumDecl::enumerator_iterator EC1 = D1->enumerator_begin(),
1111                                   EC1End = D1->enumerator_end();
1112        EC1 != EC1End; ++EC1, ++EC2) {
1113     if (EC2 == EC2End) {
1114       if (Context.Complain) {
1115         Context.Diag2(D2->getLocation(), diag::warn_odr_tag_type_inconsistent)
1116           << Context.C2.getTypeDeclType(D2);
1117         Context.Diag1(EC1->getLocation(), diag::note_odr_enumerator)
1118           << EC1->getDeclName()
1119           << EC1->getInitVal().toString(10);
1120         Context.Diag2(D2->getLocation(), diag::note_odr_missing_enumerator);
1121       }
1122       return false;
1123     }
1124 
1125     llvm::APSInt Val1 = EC1->getInitVal();
1126     llvm::APSInt Val2 = EC2->getInitVal();
1127     if (!llvm::APSInt::isSameValue(Val1, Val2) ||
1128         !IsStructurallyEquivalent(EC1->getIdentifier(), EC2->getIdentifier())) {
1129       if (Context.Complain) {
1130         Context.Diag2(D2->getLocation(), diag::warn_odr_tag_type_inconsistent)
1131           << Context.C2.getTypeDeclType(D2);
1132         Context.Diag2(EC2->getLocation(), diag::note_odr_enumerator)
1133           << EC2->getDeclName()
1134           << EC2->getInitVal().toString(10);
1135         Context.Diag1(EC1->getLocation(), diag::note_odr_enumerator)
1136           << EC1->getDeclName()
1137           << EC1->getInitVal().toString(10);
1138       }
1139       return false;
1140     }
1141   }
1142 
1143   if (EC2 != EC2End) {
1144     if (Context.Complain) {
1145       Context.Diag2(D2->getLocation(), diag::warn_odr_tag_type_inconsistent)
1146         << Context.C2.getTypeDeclType(D2);
1147       Context.Diag2(EC2->getLocation(), diag::note_odr_enumerator)
1148         << EC2->getDeclName()
1149         << EC2->getInitVal().toString(10);
1150       Context.Diag1(D1->getLocation(), diag::note_odr_missing_enumerator);
1151     }
1152     return false;
1153   }
1154 
1155   return true;
1156 }
1157 
1158 static bool IsStructurallyEquivalent(StructuralEquivalenceContext &Context,
1159                                      TemplateParameterList *Params1,
1160                                      TemplateParameterList *Params2) {
1161   if (Params1->size() != Params2->size()) {
1162     if (Context.Complain) {
1163       Context.Diag2(Params2->getTemplateLoc(),
1164                     diag::err_odr_different_num_template_parameters)
1165         << Params1->size() << Params2->size();
1166       Context.Diag1(Params1->getTemplateLoc(),
1167                     diag::note_odr_template_parameter_list);
1168     }
1169     return false;
1170   }
1171 
1172   for (unsigned I = 0, N = Params1->size(); I != N; ++I) {
1173     if (Params1->getParam(I)->getKind() != Params2->getParam(I)->getKind()) {
1174       if (Context.Complain) {
1175         Context.Diag2(Params2->getParam(I)->getLocation(),
1176                       diag::err_odr_different_template_parameter_kind);
1177         Context.Diag1(Params1->getParam(I)->getLocation(),
1178                       diag::note_odr_template_parameter_here);
1179       }
1180       return false;
1181     }
1182 
1183     if (!Context.IsStructurallyEquivalent(Params1->getParam(I),
1184                                           Params2->getParam(I))) {
1185 
1186       return false;
1187     }
1188   }
1189 
1190   return true;
1191 }
1192 
1193 static bool IsStructurallyEquivalent(StructuralEquivalenceContext &Context,
1194                                      TemplateTypeParmDecl *D1,
1195                                      TemplateTypeParmDecl *D2) {
1196   if (D1->isParameterPack() != D2->isParameterPack()) {
1197     if (Context.Complain) {
1198       Context.Diag2(D2->getLocation(), diag::err_odr_parameter_pack_non_pack)
1199         << D2->isParameterPack();
1200       Context.Diag1(D1->getLocation(), diag::note_odr_parameter_pack_non_pack)
1201         << D1->isParameterPack();
1202     }
1203     return false;
1204   }
1205 
1206   return true;
1207 }
1208 
1209 static bool IsStructurallyEquivalent(StructuralEquivalenceContext &Context,
1210                                      NonTypeTemplateParmDecl *D1,
1211                                      NonTypeTemplateParmDecl *D2) {
1212   if (D1->isParameterPack() != D2->isParameterPack()) {
1213     if (Context.Complain) {
1214       Context.Diag2(D2->getLocation(), diag::err_odr_parameter_pack_non_pack)
1215         << D2->isParameterPack();
1216       Context.Diag1(D1->getLocation(), diag::note_odr_parameter_pack_non_pack)
1217         << D1->isParameterPack();
1218     }
1219     return false;
1220   }
1221 
1222   // Check types.
1223   if (!Context.IsStructurallyEquivalent(D1->getType(), D2->getType())) {
1224     if (Context.Complain) {
1225       Context.Diag2(D2->getLocation(),
1226                     diag::err_odr_non_type_parameter_type_inconsistent)
1227         << D2->getType() << D1->getType();
1228       Context.Diag1(D1->getLocation(), diag::note_odr_value_here)
1229         << D1->getType();
1230     }
1231     return false;
1232   }
1233 
1234   return true;
1235 }
1236 
1237 static bool IsStructurallyEquivalent(StructuralEquivalenceContext &Context,
1238                                      TemplateTemplateParmDecl *D1,
1239                                      TemplateTemplateParmDecl *D2) {
1240   if (D1->isParameterPack() != D2->isParameterPack()) {
1241     if (Context.Complain) {
1242       Context.Diag2(D2->getLocation(), diag::err_odr_parameter_pack_non_pack)
1243         << D2->isParameterPack();
1244       Context.Diag1(D1->getLocation(), diag::note_odr_parameter_pack_non_pack)
1245         << D1->isParameterPack();
1246     }
1247     return false;
1248   }
1249 
1250   // Check template parameter lists.
1251   return IsStructurallyEquivalent(Context, D1->getTemplateParameters(),
1252                                   D2->getTemplateParameters());
1253 }
1254 
1255 static bool IsStructurallyEquivalent(StructuralEquivalenceContext &Context,
1256                                      ClassTemplateDecl *D1,
1257                                      ClassTemplateDecl *D2) {
1258   // Check template parameters.
1259   if (!IsStructurallyEquivalent(Context,
1260                                 D1->getTemplateParameters(),
1261                                 D2->getTemplateParameters()))
1262     return false;
1263 
1264   // Check the templated declaration.
1265   return Context.IsStructurallyEquivalent(D1->getTemplatedDecl(),
1266                                           D2->getTemplatedDecl());
1267 }
1268 
1269 /// \brief Determine structural equivalence of two declarations.
1270 static bool IsStructurallyEquivalent(StructuralEquivalenceContext &Context,
1271                                      Decl *D1, Decl *D2) {
1272   // FIXME: Check for known structural equivalences via a callback of some sort.
1273 
1274   // Check whether we already know that these two declarations are not
1275   // structurally equivalent.
1276   if (Context.NonEquivalentDecls.count(std::make_pair(D1->getCanonicalDecl(),
1277                                                       D2->getCanonicalDecl())))
1278     return false;
1279 
1280   // Determine whether we've already produced a tentative equivalence for D1.
1281   Decl *&EquivToD1 = Context.TentativeEquivalences[D1->getCanonicalDecl()];
1282   if (EquivToD1)
1283     return EquivToD1 == D2->getCanonicalDecl();
1284 
1285   // Produce a tentative equivalence D1 <-> D2, which will be checked later.
1286   EquivToD1 = D2->getCanonicalDecl();
1287   Context.DeclsToCheck.push_back(D1->getCanonicalDecl());
1288   return true;
1289 }
1290 
1291 bool StructuralEquivalenceContext::IsStructurallyEquivalent(Decl *D1,
1292                                                             Decl *D2) {
1293   if (!::IsStructurallyEquivalent(*this, D1, D2))
1294     return false;
1295 
1296   return !Finish();
1297 }
1298 
1299 bool StructuralEquivalenceContext::IsStructurallyEquivalent(QualType T1,
1300                                                             QualType T2) {
1301   if (!::IsStructurallyEquivalent(*this, T1, T2))
1302     return false;
1303 
1304   return !Finish();
1305 }
1306 
1307 bool StructuralEquivalenceContext::Finish() {
1308   while (!DeclsToCheck.empty()) {
1309     // Check the next declaration.
1310     Decl *D1 = DeclsToCheck.front();
1311     DeclsToCheck.pop_front();
1312 
1313     Decl *D2 = TentativeEquivalences[D1];
1314     assert(D2 && "Unrecorded tentative equivalence?");
1315 
1316     bool Equivalent = true;
1317 
1318     // FIXME: Switch on all declaration kinds. For now, we're just going to
1319     // check the obvious ones.
1320     if (RecordDecl *Record1 = dyn_cast<RecordDecl>(D1)) {
1321       if (RecordDecl *Record2 = dyn_cast<RecordDecl>(D2)) {
1322         // Check for equivalent structure names.
1323         IdentifierInfo *Name1 = Record1->getIdentifier();
1324         if (!Name1 && Record1->getTypedefNameForAnonDecl())
1325           Name1 = Record1->getTypedefNameForAnonDecl()->getIdentifier();
1326         IdentifierInfo *Name2 = Record2->getIdentifier();
1327         if (!Name2 && Record2->getTypedefNameForAnonDecl())
1328           Name2 = Record2->getTypedefNameForAnonDecl()->getIdentifier();
1329         if (!::IsStructurallyEquivalent(Name1, Name2) ||
1330             !::IsStructurallyEquivalent(*this, Record1, Record2))
1331           Equivalent = false;
1332       } else {
1333         // Record/non-record mismatch.
1334         Equivalent = false;
1335       }
1336     } else if (EnumDecl *Enum1 = dyn_cast<EnumDecl>(D1)) {
1337       if (EnumDecl *Enum2 = dyn_cast<EnumDecl>(D2)) {
1338         // Check for equivalent enum names.
1339         IdentifierInfo *Name1 = Enum1->getIdentifier();
1340         if (!Name1 && Enum1->getTypedefNameForAnonDecl())
1341           Name1 = Enum1->getTypedefNameForAnonDecl()->getIdentifier();
1342         IdentifierInfo *Name2 = Enum2->getIdentifier();
1343         if (!Name2 && Enum2->getTypedefNameForAnonDecl())
1344           Name2 = Enum2->getTypedefNameForAnonDecl()->getIdentifier();
1345         if (!::IsStructurallyEquivalent(Name1, Name2) ||
1346             !::IsStructurallyEquivalent(*this, Enum1, Enum2))
1347           Equivalent = false;
1348       } else {
1349         // Enum/non-enum mismatch
1350         Equivalent = false;
1351       }
1352     } else if (TypedefNameDecl *Typedef1 = dyn_cast<TypedefNameDecl>(D1)) {
1353       if (TypedefNameDecl *Typedef2 = dyn_cast<TypedefNameDecl>(D2)) {
1354         if (!::IsStructurallyEquivalent(Typedef1->getIdentifier(),
1355                                         Typedef2->getIdentifier()) ||
1356             !::IsStructurallyEquivalent(*this,
1357                                         Typedef1->getUnderlyingType(),
1358                                         Typedef2->getUnderlyingType()))
1359           Equivalent = false;
1360       } else {
1361         // Typedef/non-typedef mismatch.
1362         Equivalent = false;
1363       }
1364     } else if (ClassTemplateDecl *ClassTemplate1
1365                                            = dyn_cast<ClassTemplateDecl>(D1)) {
1366       if (ClassTemplateDecl *ClassTemplate2 = dyn_cast<ClassTemplateDecl>(D2)) {
1367         if (!::IsStructurallyEquivalent(ClassTemplate1->getIdentifier(),
1368                                         ClassTemplate2->getIdentifier()) ||
1369             !::IsStructurallyEquivalent(*this, ClassTemplate1, ClassTemplate2))
1370           Equivalent = false;
1371       } else {
1372         // Class template/non-class-template mismatch.
1373         Equivalent = false;
1374       }
1375     } else if (TemplateTypeParmDecl *TTP1= dyn_cast<TemplateTypeParmDecl>(D1)) {
1376       if (TemplateTypeParmDecl *TTP2 = dyn_cast<TemplateTypeParmDecl>(D2)) {
1377         if (!::IsStructurallyEquivalent(*this, TTP1, TTP2))
1378           Equivalent = false;
1379       } else {
1380         // Kind mismatch.
1381         Equivalent = false;
1382       }
1383     } else if (NonTypeTemplateParmDecl *NTTP1
1384                                      = dyn_cast<NonTypeTemplateParmDecl>(D1)) {
1385       if (NonTypeTemplateParmDecl *NTTP2
1386                                       = dyn_cast<NonTypeTemplateParmDecl>(D2)) {
1387         if (!::IsStructurallyEquivalent(*this, NTTP1, NTTP2))
1388           Equivalent = false;
1389       } else {
1390         // Kind mismatch.
1391         Equivalent = false;
1392       }
1393     } else if (TemplateTemplateParmDecl *TTP1
1394                                   = dyn_cast<TemplateTemplateParmDecl>(D1)) {
1395       if (TemplateTemplateParmDecl *TTP2
1396                                     = dyn_cast<TemplateTemplateParmDecl>(D2)) {
1397         if (!::IsStructurallyEquivalent(*this, TTP1, TTP2))
1398           Equivalent = false;
1399       } else {
1400         // Kind mismatch.
1401         Equivalent = false;
1402       }
1403     }
1404 
1405     if (!Equivalent) {
1406       // Note that these two declarations are not equivalent (and we already
1407       // know about it).
1408       NonEquivalentDecls.insert(std::make_pair(D1->getCanonicalDecl(),
1409                                                D2->getCanonicalDecl()));
1410       return true;
1411     }
1412     // FIXME: Check other declaration kinds!
1413   }
1414 
1415   return false;
1416 }
1417 
1418 //----------------------------------------------------------------------------
1419 // Import Types
1420 //----------------------------------------------------------------------------
1421 
1422 QualType ASTNodeImporter::VisitType(const Type *T) {
1423   Importer.FromDiag(SourceLocation(), diag::err_unsupported_ast_node)
1424     << T->getTypeClassName();
1425   return QualType();
1426 }
1427 
1428 QualType ASTNodeImporter::VisitBuiltinType(const BuiltinType *T) {
1429   switch (T->getKind()) {
1430 #define SHARED_SINGLETON_TYPE(Expansion)
1431 #define BUILTIN_TYPE(Id, SingletonId) \
1432   case BuiltinType::Id: return Importer.getToContext().SingletonId;
1433 #include "clang/AST/BuiltinTypes.def"
1434 
1435   // FIXME: for Char16, Char32, and NullPtr, make sure that the "to"
1436   // context supports C++.
1437 
1438   // FIXME: for ObjCId, ObjCClass, and ObjCSel, make sure that the "to"
1439   // context supports ObjC.
1440 
1441   case BuiltinType::Char_U:
1442     // The context we're importing from has an unsigned 'char'. If we're
1443     // importing into a context with a signed 'char', translate to
1444     // 'unsigned char' instead.
1445     if (Importer.getToContext().getLangOpts().CharIsSigned)
1446       return Importer.getToContext().UnsignedCharTy;
1447 
1448     return Importer.getToContext().CharTy;
1449 
1450   case BuiltinType::Char_S:
1451     // The context we're importing from has an unsigned 'char'. If we're
1452     // importing into a context with a signed 'char', translate to
1453     // 'unsigned char' instead.
1454     if (!Importer.getToContext().getLangOpts().CharIsSigned)
1455       return Importer.getToContext().SignedCharTy;
1456 
1457     return Importer.getToContext().CharTy;
1458 
1459   case BuiltinType::WChar_S:
1460   case BuiltinType::WChar_U:
1461     // FIXME: If not in C++, shall we translate to the C equivalent of
1462     // wchar_t?
1463     return Importer.getToContext().WCharTy;
1464   }
1465 
1466   llvm_unreachable("Invalid BuiltinType Kind!");
1467 }
1468 
1469 QualType ASTNodeImporter::VisitComplexType(const ComplexType *T) {
1470   QualType ToElementType = Importer.Import(T->getElementType());
1471   if (ToElementType.isNull())
1472     return QualType();
1473 
1474   return Importer.getToContext().getComplexType(ToElementType);
1475 }
1476 
1477 QualType ASTNodeImporter::VisitPointerType(const PointerType *T) {
1478   QualType ToPointeeType = Importer.Import(T->getPointeeType());
1479   if (ToPointeeType.isNull())
1480     return QualType();
1481 
1482   return Importer.getToContext().getPointerType(ToPointeeType);
1483 }
1484 
1485 QualType ASTNodeImporter::VisitBlockPointerType(const BlockPointerType *T) {
1486   // FIXME: Check for blocks support in "to" context.
1487   QualType ToPointeeType = Importer.Import(T->getPointeeType());
1488   if (ToPointeeType.isNull())
1489     return QualType();
1490 
1491   return Importer.getToContext().getBlockPointerType(ToPointeeType);
1492 }
1493 
1494 QualType
1495 ASTNodeImporter::VisitLValueReferenceType(const LValueReferenceType *T) {
1496   // FIXME: Check for C++ support in "to" context.
1497   QualType ToPointeeType = Importer.Import(T->getPointeeTypeAsWritten());
1498   if (ToPointeeType.isNull())
1499     return QualType();
1500 
1501   return Importer.getToContext().getLValueReferenceType(ToPointeeType);
1502 }
1503 
1504 QualType
1505 ASTNodeImporter::VisitRValueReferenceType(const RValueReferenceType *T) {
1506   // FIXME: Check for C++0x support in "to" context.
1507   QualType ToPointeeType = Importer.Import(T->getPointeeTypeAsWritten());
1508   if (ToPointeeType.isNull())
1509     return QualType();
1510 
1511   return Importer.getToContext().getRValueReferenceType(ToPointeeType);
1512 }
1513 
1514 QualType ASTNodeImporter::VisitMemberPointerType(const MemberPointerType *T) {
1515   // FIXME: Check for C++ support in "to" context.
1516   QualType ToPointeeType = Importer.Import(T->getPointeeType());
1517   if (ToPointeeType.isNull())
1518     return QualType();
1519 
1520   QualType ClassType = Importer.Import(QualType(T->getClass(), 0));
1521   return Importer.getToContext().getMemberPointerType(ToPointeeType,
1522                                                       ClassType.getTypePtr());
1523 }
1524 
1525 QualType ASTNodeImporter::VisitConstantArrayType(const ConstantArrayType *T) {
1526   QualType ToElementType = Importer.Import(T->getElementType());
1527   if (ToElementType.isNull())
1528     return QualType();
1529 
1530   return Importer.getToContext().getConstantArrayType(ToElementType,
1531                                                       T->getSize(),
1532                                                       T->getSizeModifier(),
1533                                                T->getIndexTypeCVRQualifiers());
1534 }
1535 
1536 QualType
1537 ASTNodeImporter::VisitIncompleteArrayType(const IncompleteArrayType *T) {
1538   QualType ToElementType = Importer.Import(T->getElementType());
1539   if (ToElementType.isNull())
1540     return QualType();
1541 
1542   return Importer.getToContext().getIncompleteArrayType(ToElementType,
1543                                                         T->getSizeModifier(),
1544                                                 T->getIndexTypeCVRQualifiers());
1545 }
1546 
1547 QualType ASTNodeImporter::VisitVariableArrayType(const VariableArrayType *T) {
1548   QualType ToElementType = Importer.Import(T->getElementType());
1549   if (ToElementType.isNull())
1550     return QualType();
1551 
1552   Expr *Size = Importer.Import(T->getSizeExpr());
1553   if (!Size)
1554     return QualType();
1555 
1556   SourceRange Brackets = Importer.Import(T->getBracketsRange());
1557   return Importer.getToContext().getVariableArrayType(ToElementType, Size,
1558                                                       T->getSizeModifier(),
1559                                                 T->getIndexTypeCVRQualifiers(),
1560                                                       Brackets);
1561 }
1562 
1563 QualType ASTNodeImporter::VisitVectorType(const VectorType *T) {
1564   QualType ToElementType = Importer.Import(T->getElementType());
1565   if (ToElementType.isNull())
1566     return QualType();
1567 
1568   return Importer.getToContext().getVectorType(ToElementType,
1569                                                T->getNumElements(),
1570                                                T->getVectorKind());
1571 }
1572 
1573 QualType ASTNodeImporter::VisitExtVectorType(const ExtVectorType *T) {
1574   QualType ToElementType = Importer.Import(T->getElementType());
1575   if (ToElementType.isNull())
1576     return QualType();
1577 
1578   return Importer.getToContext().getExtVectorType(ToElementType,
1579                                                   T->getNumElements());
1580 }
1581 
1582 QualType
1583 ASTNodeImporter::VisitFunctionNoProtoType(const FunctionNoProtoType *T) {
1584   // FIXME: What happens if we're importing a function without a prototype
1585   // into C++? Should we make it variadic?
1586   QualType ToResultType = Importer.Import(T->getReturnType());
1587   if (ToResultType.isNull())
1588     return QualType();
1589 
1590   return Importer.getToContext().getFunctionNoProtoType(ToResultType,
1591                                                         T->getExtInfo());
1592 }
1593 
1594 QualType ASTNodeImporter::VisitFunctionProtoType(const FunctionProtoType *T) {
1595   QualType ToResultType = Importer.Import(T->getReturnType());
1596   if (ToResultType.isNull())
1597     return QualType();
1598 
1599   // Import argument types
1600   SmallVector<QualType, 4> ArgTypes;
1601   for (const auto &A : T->param_types()) {
1602     QualType ArgType = Importer.Import(A);
1603     if (ArgType.isNull())
1604       return QualType();
1605     ArgTypes.push_back(ArgType);
1606   }
1607 
1608   // Import exception types
1609   SmallVector<QualType, 4> ExceptionTypes;
1610   for (const auto &E : T->exceptions()) {
1611     QualType ExceptionType = Importer.Import(E);
1612     if (ExceptionType.isNull())
1613       return QualType();
1614     ExceptionTypes.push_back(ExceptionType);
1615   }
1616 
1617   FunctionProtoType::ExtProtoInfo FromEPI = T->getExtProtoInfo();
1618   FunctionProtoType::ExtProtoInfo ToEPI;
1619 
1620   ToEPI.ExtInfo = FromEPI.ExtInfo;
1621   ToEPI.Variadic = FromEPI.Variadic;
1622   ToEPI.HasTrailingReturn = FromEPI.HasTrailingReturn;
1623   ToEPI.TypeQuals = FromEPI.TypeQuals;
1624   ToEPI.RefQualifier = FromEPI.RefQualifier;
1625   ToEPI.ExceptionSpec.Type = FromEPI.ExceptionSpec.Type;
1626   ToEPI.ExceptionSpec.Exceptions = ExceptionTypes;
1627   ToEPI.ExceptionSpec.NoexceptExpr =
1628       Importer.Import(FromEPI.ExceptionSpec.NoexceptExpr);
1629   ToEPI.ExceptionSpec.SourceDecl = cast_or_null<FunctionDecl>(
1630       Importer.Import(FromEPI.ExceptionSpec.SourceDecl));
1631   ToEPI.ExceptionSpec.SourceTemplate = cast_or_null<FunctionDecl>(
1632       Importer.Import(FromEPI.ExceptionSpec.SourceTemplate));
1633 
1634   return Importer.getToContext().getFunctionType(ToResultType, ArgTypes, ToEPI);
1635 }
1636 
1637 QualType ASTNodeImporter::VisitParenType(const ParenType *T) {
1638   QualType ToInnerType = Importer.Import(T->getInnerType());
1639   if (ToInnerType.isNull())
1640     return QualType();
1641 
1642   return Importer.getToContext().getParenType(ToInnerType);
1643 }
1644 
1645 QualType ASTNodeImporter::VisitTypedefType(const TypedefType *T) {
1646   TypedefNameDecl *ToDecl
1647              = dyn_cast_or_null<TypedefNameDecl>(Importer.Import(T->getDecl()));
1648   if (!ToDecl)
1649     return QualType();
1650 
1651   return Importer.getToContext().getTypeDeclType(ToDecl);
1652 }
1653 
1654 QualType ASTNodeImporter::VisitTypeOfExprType(const TypeOfExprType *T) {
1655   Expr *ToExpr = Importer.Import(T->getUnderlyingExpr());
1656   if (!ToExpr)
1657     return QualType();
1658 
1659   return Importer.getToContext().getTypeOfExprType(ToExpr);
1660 }
1661 
1662 QualType ASTNodeImporter::VisitTypeOfType(const TypeOfType *T) {
1663   QualType ToUnderlyingType = Importer.Import(T->getUnderlyingType());
1664   if (ToUnderlyingType.isNull())
1665     return QualType();
1666 
1667   return Importer.getToContext().getTypeOfType(ToUnderlyingType);
1668 }
1669 
1670 QualType ASTNodeImporter::VisitDecltypeType(const DecltypeType *T) {
1671   // FIXME: Make sure that the "to" context supports C++0x!
1672   Expr *ToExpr = Importer.Import(T->getUnderlyingExpr());
1673   if (!ToExpr)
1674     return QualType();
1675 
1676   QualType UnderlyingType = Importer.Import(T->getUnderlyingType());
1677   if (UnderlyingType.isNull())
1678     return QualType();
1679 
1680   return Importer.getToContext().getDecltypeType(ToExpr, UnderlyingType);
1681 }
1682 
1683 QualType ASTNodeImporter::VisitUnaryTransformType(const UnaryTransformType *T) {
1684   QualType ToBaseType = Importer.Import(T->getBaseType());
1685   QualType ToUnderlyingType = Importer.Import(T->getUnderlyingType());
1686   if (ToBaseType.isNull() || ToUnderlyingType.isNull())
1687     return QualType();
1688 
1689   return Importer.getToContext().getUnaryTransformType(ToBaseType,
1690                                                        ToUnderlyingType,
1691                                                        T->getUTTKind());
1692 }
1693 
1694 QualType ASTNodeImporter::VisitAutoType(const AutoType *T) {
1695   // FIXME: Make sure that the "to" context supports C++11!
1696   QualType FromDeduced = T->getDeducedType();
1697   QualType ToDeduced;
1698   if (!FromDeduced.isNull()) {
1699     ToDeduced = Importer.Import(FromDeduced);
1700     if (ToDeduced.isNull())
1701       return QualType();
1702   }
1703 
1704   return Importer.getToContext().getAutoType(ToDeduced, T->isDecltypeAuto(),
1705                                              /*IsDependent*/false);
1706 }
1707 
1708 QualType ASTNodeImporter::VisitRecordType(const RecordType *T) {
1709   RecordDecl *ToDecl
1710     = dyn_cast_or_null<RecordDecl>(Importer.Import(T->getDecl()));
1711   if (!ToDecl)
1712     return QualType();
1713 
1714   return Importer.getToContext().getTagDeclType(ToDecl);
1715 }
1716 
1717 QualType ASTNodeImporter::VisitEnumType(const EnumType *T) {
1718   EnumDecl *ToDecl
1719     = dyn_cast_or_null<EnumDecl>(Importer.Import(T->getDecl()));
1720   if (!ToDecl)
1721     return QualType();
1722 
1723   return Importer.getToContext().getTagDeclType(ToDecl);
1724 }
1725 
1726 QualType ASTNodeImporter::VisitTemplateSpecializationType(
1727                                        const TemplateSpecializationType *T) {
1728   TemplateName ToTemplate = Importer.Import(T->getTemplateName());
1729   if (ToTemplate.isNull())
1730     return QualType();
1731 
1732   SmallVector<TemplateArgument, 2> ToTemplateArgs;
1733   if (ImportTemplateArguments(T->getArgs(), T->getNumArgs(), ToTemplateArgs))
1734     return QualType();
1735 
1736   QualType ToCanonType;
1737   if (!QualType(T, 0).isCanonical()) {
1738     QualType FromCanonType
1739       = Importer.getFromContext().getCanonicalType(QualType(T, 0));
1740     ToCanonType =Importer.Import(FromCanonType);
1741     if (ToCanonType.isNull())
1742       return QualType();
1743   }
1744   return Importer.getToContext().getTemplateSpecializationType(ToTemplate,
1745                                                          ToTemplateArgs.data(),
1746                                                          ToTemplateArgs.size(),
1747                                                                ToCanonType);
1748 }
1749 
1750 QualType ASTNodeImporter::VisitElaboratedType(const ElaboratedType *T) {
1751   NestedNameSpecifier *ToQualifier = nullptr;
1752   // Note: the qualifier in an ElaboratedType is optional.
1753   if (T->getQualifier()) {
1754     ToQualifier = Importer.Import(T->getQualifier());
1755     if (!ToQualifier)
1756       return QualType();
1757   }
1758 
1759   QualType ToNamedType = Importer.Import(T->getNamedType());
1760   if (ToNamedType.isNull())
1761     return QualType();
1762 
1763   return Importer.getToContext().getElaboratedType(T->getKeyword(),
1764                                                    ToQualifier, ToNamedType);
1765 }
1766 
1767 QualType ASTNodeImporter::VisitObjCInterfaceType(const ObjCInterfaceType *T) {
1768   ObjCInterfaceDecl *Class
1769     = dyn_cast_or_null<ObjCInterfaceDecl>(Importer.Import(T->getDecl()));
1770   if (!Class)
1771     return QualType();
1772 
1773   return Importer.getToContext().getObjCInterfaceType(Class);
1774 }
1775 
1776 QualType ASTNodeImporter::VisitObjCObjectType(const ObjCObjectType *T) {
1777   QualType ToBaseType = Importer.Import(T->getBaseType());
1778   if (ToBaseType.isNull())
1779     return QualType();
1780 
1781   SmallVector<ObjCProtocolDecl *, 4> Protocols;
1782   for (auto *P : T->quals()) {
1783     ObjCProtocolDecl *Protocol
1784       = dyn_cast_or_null<ObjCProtocolDecl>(Importer.Import(P));
1785     if (!Protocol)
1786       return QualType();
1787     Protocols.push_back(Protocol);
1788   }
1789 
1790   return Importer.getToContext().getObjCObjectType(ToBaseType,
1791                                                    Protocols.data(),
1792                                                    Protocols.size());
1793 }
1794 
1795 QualType
1796 ASTNodeImporter::VisitObjCObjectPointerType(const ObjCObjectPointerType *T) {
1797   QualType ToPointeeType = Importer.Import(T->getPointeeType());
1798   if (ToPointeeType.isNull())
1799     return QualType();
1800 
1801   return Importer.getToContext().getObjCObjectPointerType(ToPointeeType);
1802 }
1803 
1804 //----------------------------------------------------------------------------
1805 // Import Declarations
1806 //----------------------------------------------------------------------------
1807 bool ASTNodeImporter::ImportDeclParts(NamedDecl *D, DeclContext *&DC,
1808                                       DeclContext *&LexicalDC,
1809                                       DeclarationName &Name,
1810                                       SourceLocation &Loc) {
1811   // Import the context of this declaration.
1812   DC = Importer.ImportContext(D->getDeclContext());
1813   if (!DC)
1814     return true;
1815 
1816   LexicalDC = DC;
1817   if (D->getDeclContext() != D->getLexicalDeclContext()) {
1818     LexicalDC = Importer.ImportContext(D->getLexicalDeclContext());
1819     if (!LexicalDC)
1820       return true;
1821   }
1822 
1823   // Import the name of this declaration.
1824   Name = Importer.Import(D->getDeclName());
1825   if (D->getDeclName() && !Name)
1826     return true;
1827 
1828   // Import the location of this declaration.
1829   Loc = Importer.Import(D->getLocation());
1830   return false;
1831 }
1832 
1833 void ASTNodeImporter::ImportDefinitionIfNeeded(Decl *FromD, Decl *ToD) {
1834   if (!FromD)
1835     return;
1836 
1837   if (!ToD) {
1838     ToD = Importer.Import(FromD);
1839     if (!ToD)
1840       return;
1841   }
1842 
1843   if (RecordDecl *FromRecord = dyn_cast<RecordDecl>(FromD)) {
1844     if (RecordDecl *ToRecord = cast_or_null<RecordDecl>(ToD)) {
1845       if (FromRecord->getDefinition() && FromRecord->isCompleteDefinition() && !ToRecord->getDefinition()) {
1846         ImportDefinition(FromRecord, ToRecord);
1847       }
1848     }
1849     return;
1850   }
1851 
1852   if (EnumDecl *FromEnum = dyn_cast<EnumDecl>(FromD)) {
1853     if (EnumDecl *ToEnum = cast_or_null<EnumDecl>(ToD)) {
1854       if (FromEnum->getDefinition() && !ToEnum->getDefinition()) {
1855         ImportDefinition(FromEnum, ToEnum);
1856       }
1857     }
1858     return;
1859   }
1860 }
1861 
1862 void
1863 ASTNodeImporter::ImportDeclarationNameLoc(const DeclarationNameInfo &From,
1864                                           DeclarationNameInfo& To) {
1865   // NOTE: To.Name and To.Loc are already imported.
1866   // We only have to import To.LocInfo.
1867   switch (To.getName().getNameKind()) {
1868   case DeclarationName::Identifier:
1869   case DeclarationName::ObjCZeroArgSelector:
1870   case DeclarationName::ObjCOneArgSelector:
1871   case DeclarationName::ObjCMultiArgSelector:
1872   case DeclarationName::CXXUsingDirective:
1873     return;
1874 
1875   case DeclarationName::CXXOperatorName: {
1876     SourceRange Range = From.getCXXOperatorNameRange();
1877     To.setCXXOperatorNameRange(Importer.Import(Range));
1878     return;
1879   }
1880   case DeclarationName::CXXLiteralOperatorName: {
1881     SourceLocation Loc = From.getCXXLiteralOperatorNameLoc();
1882     To.setCXXLiteralOperatorNameLoc(Importer.Import(Loc));
1883     return;
1884   }
1885   case DeclarationName::CXXConstructorName:
1886   case DeclarationName::CXXDestructorName:
1887   case DeclarationName::CXXConversionFunctionName: {
1888     TypeSourceInfo *FromTInfo = From.getNamedTypeInfo();
1889     To.setNamedTypeInfo(Importer.Import(FromTInfo));
1890     return;
1891   }
1892   }
1893   llvm_unreachable("Unknown name kind.");
1894 }
1895 
1896 void ASTNodeImporter::ImportDeclContext(DeclContext *FromDC, bool ForceImport) {
1897   if (Importer.isMinimalImport() && !ForceImport) {
1898     Importer.ImportContext(FromDC);
1899     return;
1900   }
1901 
1902   for (auto *From : FromDC->decls())
1903     Importer.Import(From);
1904 }
1905 
1906 bool ASTNodeImporter::ImportDefinition(RecordDecl *From, RecordDecl *To,
1907                                        ImportDefinitionKind Kind) {
1908   if (To->getDefinition() || To->isBeingDefined()) {
1909     if (Kind == IDK_Everything)
1910       ImportDeclContext(From, /*ForceImport=*/true);
1911 
1912     return false;
1913   }
1914 
1915   To->startDefinition();
1916 
1917   // Add base classes.
1918   if (CXXRecordDecl *ToCXX = dyn_cast<CXXRecordDecl>(To)) {
1919     CXXRecordDecl *FromCXX = cast<CXXRecordDecl>(From);
1920 
1921     struct CXXRecordDecl::DefinitionData &ToData = ToCXX->data();
1922     struct CXXRecordDecl::DefinitionData &FromData = FromCXX->data();
1923     ToData.UserDeclaredConstructor = FromData.UserDeclaredConstructor;
1924     ToData.UserDeclaredSpecialMembers = FromData.UserDeclaredSpecialMembers;
1925     ToData.Aggregate = FromData.Aggregate;
1926     ToData.PlainOldData = FromData.PlainOldData;
1927     ToData.Empty = FromData.Empty;
1928     ToData.Polymorphic = FromData.Polymorphic;
1929     ToData.Abstract = FromData.Abstract;
1930     ToData.IsStandardLayout = FromData.IsStandardLayout;
1931     ToData.HasNoNonEmptyBases = FromData.HasNoNonEmptyBases;
1932     ToData.HasPrivateFields = FromData.HasPrivateFields;
1933     ToData.HasProtectedFields = FromData.HasProtectedFields;
1934     ToData.HasPublicFields = FromData.HasPublicFields;
1935     ToData.HasMutableFields = FromData.HasMutableFields;
1936     ToData.HasVariantMembers = FromData.HasVariantMembers;
1937     ToData.HasOnlyCMembers = FromData.HasOnlyCMembers;
1938     ToData.HasInClassInitializer = FromData.HasInClassInitializer;
1939     ToData.HasUninitializedReferenceMember
1940       = FromData.HasUninitializedReferenceMember;
1941     ToData.NeedOverloadResolutionForMoveConstructor
1942       = FromData.NeedOverloadResolutionForMoveConstructor;
1943     ToData.NeedOverloadResolutionForMoveAssignment
1944       = FromData.NeedOverloadResolutionForMoveAssignment;
1945     ToData.NeedOverloadResolutionForDestructor
1946       = FromData.NeedOverloadResolutionForDestructor;
1947     ToData.DefaultedMoveConstructorIsDeleted
1948       = FromData.DefaultedMoveConstructorIsDeleted;
1949     ToData.DefaultedMoveAssignmentIsDeleted
1950       = FromData.DefaultedMoveAssignmentIsDeleted;
1951     ToData.DefaultedDestructorIsDeleted = FromData.DefaultedDestructorIsDeleted;
1952     ToData.HasTrivialSpecialMembers = FromData.HasTrivialSpecialMembers;
1953     ToData.HasIrrelevantDestructor = FromData.HasIrrelevantDestructor;
1954     ToData.HasConstexprNonCopyMoveConstructor
1955       = FromData.HasConstexprNonCopyMoveConstructor;
1956     ToData.DefaultedDefaultConstructorIsConstexpr
1957       = FromData.DefaultedDefaultConstructorIsConstexpr;
1958     ToData.HasConstexprDefaultConstructor
1959       = FromData.HasConstexprDefaultConstructor;
1960     ToData.HasNonLiteralTypeFieldsOrBases
1961       = FromData.HasNonLiteralTypeFieldsOrBases;
1962     // ComputedVisibleConversions not imported.
1963     ToData.UserProvidedDefaultConstructor
1964       = FromData.UserProvidedDefaultConstructor;
1965     ToData.DeclaredSpecialMembers = FromData.DeclaredSpecialMembers;
1966     ToData.ImplicitCopyConstructorHasConstParam
1967       = FromData.ImplicitCopyConstructorHasConstParam;
1968     ToData.ImplicitCopyAssignmentHasConstParam
1969       = FromData.ImplicitCopyAssignmentHasConstParam;
1970     ToData.HasDeclaredCopyConstructorWithConstParam
1971       = FromData.HasDeclaredCopyConstructorWithConstParam;
1972     ToData.HasDeclaredCopyAssignmentWithConstParam
1973       = FromData.HasDeclaredCopyAssignmentWithConstParam;
1974     ToData.IsLambda = FromData.IsLambda;
1975 
1976     SmallVector<CXXBaseSpecifier *, 4> Bases;
1977     for (const auto &Base1 : FromCXX->bases()) {
1978       QualType T = Importer.Import(Base1.getType());
1979       if (T.isNull())
1980         return true;
1981 
1982       SourceLocation EllipsisLoc;
1983       if (Base1.isPackExpansion())
1984         EllipsisLoc = Importer.Import(Base1.getEllipsisLoc());
1985 
1986       // Ensure that we have a definition for the base.
1987       ImportDefinitionIfNeeded(Base1.getType()->getAsCXXRecordDecl());
1988 
1989       Bases.push_back(
1990                     new (Importer.getToContext())
1991                       CXXBaseSpecifier(Importer.Import(Base1.getSourceRange()),
1992                                        Base1.isVirtual(),
1993                                        Base1.isBaseOfClass(),
1994                                        Base1.getAccessSpecifierAsWritten(),
1995                                    Importer.Import(Base1.getTypeSourceInfo()),
1996                                        EllipsisLoc));
1997     }
1998     if (!Bases.empty())
1999       ToCXX->setBases(Bases.data(), Bases.size());
2000   }
2001 
2002   if (shouldForceImportDeclContext(Kind))
2003     ImportDeclContext(From, /*ForceImport=*/true);
2004 
2005   To->completeDefinition();
2006   return false;
2007 }
2008 
2009 bool ASTNodeImporter::ImportDefinition(VarDecl *From, VarDecl *To,
2010                                        ImportDefinitionKind Kind) {
2011   if (To->getDefinition())
2012     return false;
2013 
2014   // FIXME: Can we really import any initializer? Alternatively, we could force
2015   // ourselves to import every declaration of a variable and then only use
2016   // getInit() here.
2017   To->setInit(Importer.Import(const_cast<Expr *>(From->getAnyInitializer())));
2018 
2019   // FIXME: Other bits to merge?
2020 
2021   return false;
2022 }
2023 
2024 bool ASTNodeImporter::ImportDefinition(EnumDecl *From, EnumDecl *To,
2025                                        ImportDefinitionKind Kind) {
2026   if (To->getDefinition() || To->isBeingDefined()) {
2027     if (Kind == IDK_Everything)
2028       ImportDeclContext(From, /*ForceImport=*/true);
2029     return false;
2030   }
2031 
2032   To->startDefinition();
2033 
2034   QualType T = Importer.Import(Importer.getFromContext().getTypeDeclType(From));
2035   if (T.isNull())
2036     return true;
2037 
2038   QualType ToPromotionType = Importer.Import(From->getPromotionType());
2039   if (ToPromotionType.isNull())
2040     return true;
2041 
2042   if (shouldForceImportDeclContext(Kind))
2043     ImportDeclContext(From, /*ForceImport=*/true);
2044 
2045   // FIXME: we might need to merge the number of positive or negative bits
2046   // if the enumerator lists don't match.
2047   To->completeDefinition(T, ToPromotionType,
2048                          From->getNumPositiveBits(),
2049                          From->getNumNegativeBits());
2050   return false;
2051 }
2052 
2053 TemplateParameterList *ASTNodeImporter::ImportTemplateParameterList(
2054                                                 TemplateParameterList *Params) {
2055   SmallVector<NamedDecl *, 4> ToParams;
2056   ToParams.reserve(Params->size());
2057   for (TemplateParameterList::iterator P = Params->begin(),
2058                                     PEnd = Params->end();
2059        P != PEnd; ++P) {
2060     Decl *To = Importer.Import(*P);
2061     if (!To)
2062       return nullptr;
2063 
2064     ToParams.push_back(cast<NamedDecl>(To));
2065   }
2066 
2067   return TemplateParameterList::Create(Importer.getToContext(),
2068                                        Importer.Import(Params->getTemplateLoc()),
2069                                        Importer.Import(Params->getLAngleLoc()),
2070                                        ToParams.data(), ToParams.size(),
2071                                        Importer.Import(Params->getRAngleLoc()));
2072 }
2073 
2074 TemplateArgument
2075 ASTNodeImporter::ImportTemplateArgument(const TemplateArgument &From) {
2076   switch (From.getKind()) {
2077   case TemplateArgument::Null:
2078     return TemplateArgument();
2079 
2080   case TemplateArgument::Type: {
2081     QualType ToType = Importer.Import(From.getAsType());
2082     if (ToType.isNull())
2083       return TemplateArgument();
2084     return TemplateArgument(ToType);
2085   }
2086 
2087   case TemplateArgument::Integral: {
2088     QualType ToType = Importer.Import(From.getIntegralType());
2089     if (ToType.isNull())
2090       return TemplateArgument();
2091     return TemplateArgument(From, ToType);
2092   }
2093 
2094   case TemplateArgument::Declaration: {
2095     ValueDecl *To = cast_or_null<ValueDecl>(Importer.Import(From.getAsDecl()));
2096     QualType ToType = Importer.Import(From.getParamTypeForDecl());
2097     if (!To || ToType.isNull())
2098       return TemplateArgument();
2099     return TemplateArgument(To, ToType);
2100   }
2101 
2102   case TemplateArgument::NullPtr: {
2103     QualType ToType = Importer.Import(From.getNullPtrType());
2104     if (ToType.isNull())
2105       return TemplateArgument();
2106     return TemplateArgument(ToType, /*isNullPtr*/true);
2107   }
2108 
2109   case TemplateArgument::Template: {
2110     TemplateName ToTemplate = Importer.Import(From.getAsTemplate());
2111     if (ToTemplate.isNull())
2112       return TemplateArgument();
2113 
2114     return TemplateArgument(ToTemplate);
2115   }
2116 
2117   case TemplateArgument::TemplateExpansion: {
2118     TemplateName ToTemplate
2119       = Importer.Import(From.getAsTemplateOrTemplatePattern());
2120     if (ToTemplate.isNull())
2121       return TemplateArgument();
2122 
2123     return TemplateArgument(ToTemplate, From.getNumTemplateExpansions());
2124   }
2125 
2126   case TemplateArgument::Expression:
2127     if (Expr *ToExpr = Importer.Import(From.getAsExpr()))
2128       return TemplateArgument(ToExpr);
2129     return TemplateArgument();
2130 
2131   case TemplateArgument::Pack: {
2132     SmallVector<TemplateArgument, 2> ToPack;
2133     ToPack.reserve(From.pack_size());
2134     if (ImportTemplateArguments(From.pack_begin(), From.pack_size(), ToPack))
2135       return TemplateArgument();
2136 
2137     TemplateArgument *ToArgs
2138       = new (Importer.getToContext()) TemplateArgument[ToPack.size()];
2139     std::copy(ToPack.begin(), ToPack.end(), ToArgs);
2140     return TemplateArgument(ToArgs, ToPack.size());
2141   }
2142   }
2143 
2144   llvm_unreachable("Invalid template argument kind");
2145 }
2146 
2147 bool ASTNodeImporter::ImportTemplateArguments(const TemplateArgument *FromArgs,
2148                                               unsigned NumFromArgs,
2149                               SmallVectorImpl<TemplateArgument> &ToArgs) {
2150   for (unsigned I = 0; I != NumFromArgs; ++I) {
2151     TemplateArgument To = ImportTemplateArgument(FromArgs[I]);
2152     if (To.isNull() && !FromArgs[I].isNull())
2153       return true;
2154 
2155     ToArgs.push_back(To);
2156   }
2157 
2158   return false;
2159 }
2160 
2161 bool ASTNodeImporter::IsStructuralMatch(RecordDecl *FromRecord,
2162                                         RecordDecl *ToRecord, bool Complain) {
2163   // Eliminate a potential failure point where we attempt to re-import
2164   // something we're trying to import while completing ToRecord.
2165   Decl *ToOrigin = Importer.GetOriginalDecl(ToRecord);
2166   if (ToOrigin) {
2167     RecordDecl *ToOriginRecord = dyn_cast<RecordDecl>(ToOrigin);
2168     if (ToOriginRecord)
2169       ToRecord = ToOriginRecord;
2170   }
2171 
2172   StructuralEquivalenceContext Ctx(Importer.getFromContext(),
2173                                    ToRecord->getASTContext(),
2174                                    Importer.getNonEquivalentDecls(),
2175                                    false, Complain);
2176   return Ctx.IsStructurallyEquivalent(FromRecord, ToRecord);
2177 }
2178 
2179 bool ASTNodeImporter::IsStructuralMatch(VarDecl *FromVar, VarDecl *ToVar,
2180                                         bool Complain) {
2181   StructuralEquivalenceContext Ctx(
2182       Importer.getFromContext(), Importer.getToContext(),
2183       Importer.getNonEquivalentDecls(), false, Complain);
2184   return Ctx.IsStructurallyEquivalent(FromVar, ToVar);
2185 }
2186 
2187 bool ASTNodeImporter::IsStructuralMatch(EnumDecl *FromEnum, EnumDecl *ToEnum) {
2188   StructuralEquivalenceContext Ctx(Importer.getFromContext(),
2189                                    Importer.getToContext(),
2190                                    Importer.getNonEquivalentDecls());
2191   return Ctx.IsStructurallyEquivalent(FromEnum, ToEnum);
2192 }
2193 
2194 bool ASTNodeImporter::IsStructuralMatch(EnumConstantDecl *FromEC,
2195                                         EnumConstantDecl *ToEC)
2196 {
2197   const llvm::APSInt &FromVal = FromEC->getInitVal();
2198   const llvm::APSInt &ToVal = ToEC->getInitVal();
2199 
2200   return FromVal.isSigned() == ToVal.isSigned() &&
2201          FromVal.getBitWidth() == ToVal.getBitWidth() &&
2202          FromVal == ToVal;
2203 }
2204 
2205 bool ASTNodeImporter::IsStructuralMatch(ClassTemplateDecl *From,
2206                                         ClassTemplateDecl *To) {
2207   StructuralEquivalenceContext Ctx(Importer.getFromContext(),
2208                                    Importer.getToContext(),
2209                                    Importer.getNonEquivalentDecls());
2210   return Ctx.IsStructurallyEquivalent(From, To);
2211 }
2212 
2213 bool ASTNodeImporter::IsStructuralMatch(VarTemplateDecl *From,
2214                                         VarTemplateDecl *To) {
2215   StructuralEquivalenceContext Ctx(Importer.getFromContext(),
2216                                    Importer.getToContext(),
2217                                    Importer.getNonEquivalentDecls());
2218   return Ctx.IsStructurallyEquivalent(From, To);
2219 }
2220 
2221 Decl *ASTNodeImporter::VisitDecl(Decl *D) {
2222   Importer.FromDiag(D->getLocation(), diag::err_unsupported_ast_node)
2223     << D->getDeclKindName();
2224   return nullptr;
2225 }
2226 
2227 Decl *ASTNodeImporter::VisitTranslationUnitDecl(TranslationUnitDecl *D) {
2228   TranslationUnitDecl *ToD =
2229     Importer.getToContext().getTranslationUnitDecl();
2230 
2231   Importer.Imported(D, ToD);
2232 
2233   return ToD;
2234 }
2235 
2236 Decl *ASTNodeImporter::VisitNamespaceDecl(NamespaceDecl *D) {
2237   // Import the major distinguishing characteristics of this namespace.
2238   DeclContext *DC, *LexicalDC;
2239   DeclarationName Name;
2240   SourceLocation Loc;
2241   if (ImportDeclParts(D, DC, LexicalDC, Name, Loc))
2242     return nullptr;
2243 
2244   NamespaceDecl *MergeWithNamespace = nullptr;
2245   if (!Name) {
2246     // This is an anonymous namespace. Adopt an existing anonymous
2247     // namespace if we can.
2248     // FIXME: Not testable.
2249     if (TranslationUnitDecl *TU = dyn_cast<TranslationUnitDecl>(DC))
2250       MergeWithNamespace = TU->getAnonymousNamespace();
2251     else
2252       MergeWithNamespace = cast<NamespaceDecl>(DC)->getAnonymousNamespace();
2253   } else {
2254     SmallVector<NamedDecl *, 4> ConflictingDecls;
2255     SmallVector<NamedDecl *, 2> FoundDecls;
2256     DC->localUncachedLookup(Name, FoundDecls);
2257     for (unsigned I = 0, N = FoundDecls.size(); I != N; ++I) {
2258       if (!FoundDecls[I]->isInIdentifierNamespace(Decl::IDNS_Namespace))
2259         continue;
2260 
2261       if (NamespaceDecl *FoundNS = dyn_cast<NamespaceDecl>(FoundDecls[I])) {
2262         MergeWithNamespace = FoundNS;
2263         ConflictingDecls.clear();
2264         break;
2265       }
2266 
2267       ConflictingDecls.push_back(FoundDecls[I]);
2268     }
2269 
2270     if (!ConflictingDecls.empty()) {
2271       Name = Importer.HandleNameConflict(Name, DC, Decl::IDNS_Namespace,
2272                                          ConflictingDecls.data(),
2273                                          ConflictingDecls.size());
2274     }
2275   }
2276 
2277   // Create the "to" namespace, if needed.
2278   NamespaceDecl *ToNamespace = MergeWithNamespace;
2279   if (!ToNamespace) {
2280     ToNamespace = NamespaceDecl::Create(Importer.getToContext(), DC,
2281                                         D->isInline(),
2282                                         Importer.Import(D->getLocStart()),
2283                                         Loc, Name.getAsIdentifierInfo(),
2284                                         /*PrevDecl=*/nullptr);
2285     ToNamespace->setLexicalDeclContext(LexicalDC);
2286     LexicalDC->addDeclInternal(ToNamespace);
2287 
2288     // If this is an anonymous namespace, register it as the anonymous
2289     // namespace within its context.
2290     if (!Name) {
2291       if (TranslationUnitDecl *TU = dyn_cast<TranslationUnitDecl>(DC))
2292         TU->setAnonymousNamespace(ToNamespace);
2293       else
2294         cast<NamespaceDecl>(DC)->setAnonymousNamespace(ToNamespace);
2295     }
2296   }
2297   Importer.Imported(D, ToNamespace);
2298 
2299   ImportDeclContext(D);
2300 
2301   return ToNamespace;
2302 }
2303 
2304 Decl *ASTNodeImporter::VisitTypedefNameDecl(TypedefNameDecl *D, bool IsAlias) {
2305   // Import the major distinguishing characteristics of this typedef.
2306   DeclContext *DC, *LexicalDC;
2307   DeclarationName Name;
2308   SourceLocation Loc;
2309   if (ImportDeclParts(D, DC, LexicalDC, Name, Loc))
2310     return nullptr;
2311 
2312   // If this typedef is not in block scope, determine whether we've
2313   // seen a typedef with the same name (that we can merge with) or any
2314   // other entity by that name (which name lookup could conflict with).
2315   if (!DC->isFunctionOrMethod()) {
2316     SmallVector<NamedDecl *, 4> ConflictingDecls;
2317     unsigned IDNS = Decl::IDNS_Ordinary;
2318     SmallVector<NamedDecl *, 2> FoundDecls;
2319     DC->localUncachedLookup(Name, FoundDecls);
2320     for (unsigned I = 0, N = FoundDecls.size(); I != N; ++I) {
2321       if (!FoundDecls[I]->isInIdentifierNamespace(IDNS))
2322         continue;
2323       if (TypedefNameDecl *FoundTypedef =
2324             dyn_cast<TypedefNameDecl>(FoundDecls[I])) {
2325         if (Importer.IsStructurallyEquivalent(D->getUnderlyingType(),
2326                                             FoundTypedef->getUnderlyingType()))
2327           return Importer.Imported(D, FoundTypedef);
2328       }
2329 
2330       ConflictingDecls.push_back(FoundDecls[I]);
2331     }
2332 
2333     if (!ConflictingDecls.empty()) {
2334       Name = Importer.HandleNameConflict(Name, DC, IDNS,
2335                                          ConflictingDecls.data(),
2336                                          ConflictingDecls.size());
2337       if (!Name)
2338         return nullptr;
2339     }
2340   }
2341 
2342   // Import the underlying type of this typedef;
2343   QualType T = Importer.Import(D->getUnderlyingType());
2344   if (T.isNull())
2345     return nullptr;
2346 
2347   // Create the new typedef node.
2348   TypeSourceInfo *TInfo = Importer.Import(D->getTypeSourceInfo());
2349   SourceLocation StartL = Importer.Import(D->getLocStart());
2350   TypedefNameDecl *ToTypedef;
2351   if (IsAlias)
2352     ToTypedef = TypeAliasDecl::Create(Importer.getToContext(), DC,
2353                                       StartL, Loc,
2354                                       Name.getAsIdentifierInfo(),
2355                                       TInfo);
2356   else
2357     ToTypedef = TypedefDecl::Create(Importer.getToContext(), DC,
2358                                     StartL, Loc,
2359                                     Name.getAsIdentifierInfo(),
2360                                     TInfo);
2361 
2362   ToTypedef->setAccess(D->getAccess());
2363   ToTypedef->setLexicalDeclContext(LexicalDC);
2364   Importer.Imported(D, ToTypedef);
2365   LexicalDC->addDeclInternal(ToTypedef);
2366 
2367   return ToTypedef;
2368 }
2369 
2370 Decl *ASTNodeImporter::VisitTypedefDecl(TypedefDecl *D) {
2371   return VisitTypedefNameDecl(D, /*IsAlias=*/false);
2372 }
2373 
2374 Decl *ASTNodeImporter::VisitTypeAliasDecl(TypeAliasDecl *D) {
2375   return VisitTypedefNameDecl(D, /*IsAlias=*/true);
2376 }
2377 
2378 Decl *ASTNodeImporter::VisitEnumDecl(EnumDecl *D) {
2379   // Import the major distinguishing characteristics of this enum.
2380   DeclContext *DC, *LexicalDC;
2381   DeclarationName Name;
2382   SourceLocation Loc;
2383   if (ImportDeclParts(D, DC, LexicalDC, Name, Loc))
2384     return nullptr;
2385 
2386   // Figure out what enum name we're looking for.
2387   unsigned IDNS = Decl::IDNS_Tag;
2388   DeclarationName SearchName = Name;
2389   if (!SearchName && D->getTypedefNameForAnonDecl()) {
2390     SearchName = Importer.Import(D->getTypedefNameForAnonDecl()->getDeclName());
2391     IDNS = Decl::IDNS_Ordinary;
2392   } else if (Importer.getToContext().getLangOpts().CPlusPlus)
2393     IDNS |= Decl::IDNS_Ordinary;
2394 
2395   // We may already have an enum of the same name; try to find and match it.
2396   if (!DC->isFunctionOrMethod() && SearchName) {
2397     SmallVector<NamedDecl *, 4> ConflictingDecls;
2398     SmallVector<NamedDecl *, 2> FoundDecls;
2399     DC->localUncachedLookup(SearchName, FoundDecls);
2400     for (unsigned I = 0, N = FoundDecls.size(); I != N; ++I) {
2401       if (!FoundDecls[I]->isInIdentifierNamespace(IDNS))
2402         continue;
2403 
2404       Decl *Found = FoundDecls[I];
2405       if (TypedefNameDecl *Typedef = dyn_cast<TypedefNameDecl>(Found)) {
2406         if (const TagType *Tag = Typedef->getUnderlyingType()->getAs<TagType>())
2407           Found = Tag->getDecl();
2408       }
2409 
2410       if (EnumDecl *FoundEnum = dyn_cast<EnumDecl>(Found)) {
2411         if (IsStructuralMatch(D, FoundEnum))
2412           return Importer.Imported(D, FoundEnum);
2413       }
2414 
2415       ConflictingDecls.push_back(FoundDecls[I]);
2416     }
2417 
2418     if (!ConflictingDecls.empty()) {
2419       Name = Importer.HandleNameConflict(Name, DC, IDNS,
2420                                          ConflictingDecls.data(),
2421                                          ConflictingDecls.size());
2422     }
2423   }
2424 
2425   // Create the enum declaration.
2426   EnumDecl *D2 = EnumDecl::Create(Importer.getToContext(), DC,
2427                                   Importer.Import(D->getLocStart()),
2428                                   Loc, Name.getAsIdentifierInfo(), nullptr,
2429                                   D->isScoped(), D->isScopedUsingClassTag(),
2430                                   D->isFixed());
2431   // Import the qualifier, if any.
2432   D2->setQualifierInfo(Importer.Import(D->getQualifierLoc()));
2433   D2->setAccess(D->getAccess());
2434   D2->setLexicalDeclContext(LexicalDC);
2435   Importer.Imported(D, D2);
2436   LexicalDC->addDeclInternal(D2);
2437 
2438   // Import the integer type.
2439   QualType ToIntegerType = Importer.Import(D->getIntegerType());
2440   if (ToIntegerType.isNull())
2441     return nullptr;
2442   D2->setIntegerType(ToIntegerType);
2443 
2444   // Import the definition
2445   if (D->isCompleteDefinition() && ImportDefinition(D, D2))
2446     return nullptr;
2447 
2448   return D2;
2449 }
2450 
2451 Decl *ASTNodeImporter::VisitRecordDecl(RecordDecl *D) {
2452   // If this record has a definition in the translation unit we're coming from,
2453   // but this particular declaration is not that definition, import the
2454   // definition and map to that.
2455   TagDecl *Definition = D->getDefinition();
2456   if (Definition && Definition != D) {
2457     Decl *ImportedDef = Importer.Import(Definition);
2458     if (!ImportedDef)
2459       return nullptr;
2460 
2461     return Importer.Imported(D, ImportedDef);
2462   }
2463 
2464   // Import the major distinguishing characteristics of this record.
2465   DeclContext *DC, *LexicalDC;
2466   DeclarationName Name;
2467   SourceLocation Loc;
2468   if (ImportDeclParts(D, DC, LexicalDC, Name, Loc))
2469     return nullptr;
2470 
2471   // Figure out what structure name we're looking for.
2472   unsigned IDNS = Decl::IDNS_Tag;
2473   DeclarationName SearchName = Name;
2474   if (!SearchName && D->getTypedefNameForAnonDecl()) {
2475     SearchName = Importer.Import(D->getTypedefNameForAnonDecl()->getDeclName());
2476     IDNS = Decl::IDNS_Ordinary;
2477   } else if (Importer.getToContext().getLangOpts().CPlusPlus)
2478     IDNS |= Decl::IDNS_Ordinary;
2479 
2480   // We may already have a record of the same name; try to find and match it.
2481   RecordDecl *AdoptDecl = nullptr;
2482   if (!DC->isFunctionOrMethod()) {
2483     SmallVector<NamedDecl *, 4> ConflictingDecls;
2484     SmallVector<NamedDecl *, 2> FoundDecls;
2485     DC->localUncachedLookup(SearchName, FoundDecls);
2486     for (unsigned I = 0, N = FoundDecls.size(); I != N; ++I) {
2487       if (!FoundDecls[I]->isInIdentifierNamespace(IDNS))
2488         continue;
2489 
2490       Decl *Found = FoundDecls[I];
2491       if (TypedefNameDecl *Typedef = dyn_cast<TypedefNameDecl>(Found)) {
2492         if (const TagType *Tag = Typedef->getUnderlyingType()->getAs<TagType>())
2493           Found = Tag->getDecl();
2494       }
2495 
2496       if (RecordDecl *FoundRecord = dyn_cast<RecordDecl>(Found)) {
2497         if (D->isAnonymousStructOrUnion() &&
2498             FoundRecord->isAnonymousStructOrUnion()) {
2499           // If both anonymous structs/unions are in a record context, make sure
2500           // they occur in the same location in the context records.
2501           if (Optional<unsigned> Index1
2502               = findAnonymousStructOrUnionIndex(D)) {
2503             if (Optional<unsigned> Index2 =
2504                     findAnonymousStructOrUnionIndex(FoundRecord)) {
2505               if (*Index1 != *Index2)
2506                 continue;
2507             }
2508           }
2509         }
2510 
2511         if (RecordDecl *FoundDef = FoundRecord->getDefinition()) {
2512           if ((SearchName && !D->isCompleteDefinition())
2513               || (D->isCompleteDefinition() &&
2514                   D->isAnonymousStructOrUnion()
2515                     == FoundDef->isAnonymousStructOrUnion() &&
2516                   IsStructuralMatch(D, FoundDef))) {
2517             // The record types structurally match, or the "from" translation
2518             // unit only had a forward declaration anyway; call it the same
2519             // function.
2520             // FIXME: For C++, we should also merge methods here.
2521             return Importer.Imported(D, FoundDef);
2522           }
2523         } else if (!D->isCompleteDefinition()) {
2524           // We have a forward declaration of this type, so adopt that forward
2525           // declaration rather than building a new one.
2526 
2527           // If one or both can be completed from external storage then try one
2528           // last time to complete and compare them before doing this.
2529 
2530           if (FoundRecord->hasExternalLexicalStorage() &&
2531               !FoundRecord->isCompleteDefinition())
2532             FoundRecord->getASTContext().getExternalSource()->CompleteType(FoundRecord);
2533           if (D->hasExternalLexicalStorage())
2534             D->getASTContext().getExternalSource()->CompleteType(D);
2535 
2536           if (FoundRecord->isCompleteDefinition() &&
2537               D->isCompleteDefinition() &&
2538               !IsStructuralMatch(D, FoundRecord))
2539             continue;
2540 
2541           AdoptDecl = FoundRecord;
2542           continue;
2543         } else if (!SearchName) {
2544           continue;
2545         }
2546       }
2547 
2548       ConflictingDecls.push_back(FoundDecls[I]);
2549     }
2550 
2551     if (!ConflictingDecls.empty() && SearchName) {
2552       Name = Importer.HandleNameConflict(Name, DC, IDNS,
2553                                          ConflictingDecls.data(),
2554                                          ConflictingDecls.size());
2555     }
2556   }
2557 
2558   // Create the record declaration.
2559   RecordDecl *D2 = AdoptDecl;
2560   SourceLocation StartLoc = Importer.Import(D->getLocStart());
2561   if (!D2) {
2562     if (isa<CXXRecordDecl>(D)) {
2563       CXXRecordDecl *D2CXX = CXXRecordDecl::Create(Importer.getToContext(),
2564                                                    D->getTagKind(),
2565                                                    DC, StartLoc, Loc,
2566                                                    Name.getAsIdentifierInfo());
2567       D2 = D2CXX;
2568       D2->setAccess(D->getAccess());
2569     } else {
2570       D2 = RecordDecl::Create(Importer.getToContext(), D->getTagKind(),
2571                               DC, StartLoc, Loc, Name.getAsIdentifierInfo());
2572     }
2573 
2574     D2->setQualifierInfo(Importer.Import(D->getQualifierLoc()));
2575     D2->setLexicalDeclContext(LexicalDC);
2576     LexicalDC->addDeclInternal(D2);
2577     if (D->isAnonymousStructOrUnion())
2578       D2->setAnonymousStructOrUnion(true);
2579   }
2580 
2581   Importer.Imported(D, D2);
2582 
2583   if (D->isCompleteDefinition() && ImportDefinition(D, D2, IDK_Default))
2584     return nullptr;
2585 
2586   return D2;
2587 }
2588 
2589 Decl *ASTNodeImporter::VisitEnumConstantDecl(EnumConstantDecl *D) {
2590   // Import the major distinguishing characteristics of this enumerator.
2591   DeclContext *DC, *LexicalDC;
2592   DeclarationName Name;
2593   SourceLocation Loc;
2594   if (ImportDeclParts(D, DC, LexicalDC, Name, Loc))
2595     return nullptr;
2596 
2597   QualType T = Importer.Import(D->getType());
2598   if (T.isNull())
2599     return nullptr;
2600 
2601   // Determine whether there are any other declarations with the same name and
2602   // in the same context.
2603   if (!LexicalDC->isFunctionOrMethod()) {
2604     SmallVector<NamedDecl *, 4> ConflictingDecls;
2605     unsigned IDNS = Decl::IDNS_Ordinary;
2606     SmallVector<NamedDecl *, 2> FoundDecls;
2607     DC->localUncachedLookup(Name, FoundDecls);
2608     for (unsigned I = 0, N = FoundDecls.size(); I != N; ++I) {
2609       if (!FoundDecls[I]->isInIdentifierNamespace(IDNS))
2610         continue;
2611 
2612       if (EnumConstantDecl *FoundEnumConstant
2613             = dyn_cast<EnumConstantDecl>(FoundDecls[I])) {
2614         if (IsStructuralMatch(D, FoundEnumConstant))
2615           return Importer.Imported(D, FoundEnumConstant);
2616       }
2617 
2618       ConflictingDecls.push_back(FoundDecls[I]);
2619     }
2620 
2621     if (!ConflictingDecls.empty()) {
2622       Name = Importer.HandleNameConflict(Name, DC, IDNS,
2623                                          ConflictingDecls.data(),
2624                                          ConflictingDecls.size());
2625       if (!Name)
2626         return nullptr;
2627     }
2628   }
2629 
2630   Expr *Init = Importer.Import(D->getInitExpr());
2631   if (D->getInitExpr() && !Init)
2632     return nullptr;
2633 
2634   EnumConstantDecl *ToEnumerator
2635     = EnumConstantDecl::Create(Importer.getToContext(), cast<EnumDecl>(DC), Loc,
2636                                Name.getAsIdentifierInfo(), T,
2637                                Init, D->getInitVal());
2638   ToEnumerator->setAccess(D->getAccess());
2639   ToEnumerator->setLexicalDeclContext(LexicalDC);
2640   Importer.Imported(D, ToEnumerator);
2641   LexicalDC->addDeclInternal(ToEnumerator);
2642   return ToEnumerator;
2643 }
2644 
2645 Decl *ASTNodeImporter::VisitFunctionDecl(FunctionDecl *D) {
2646   // Import the major distinguishing characteristics of this function.
2647   DeclContext *DC, *LexicalDC;
2648   DeclarationName Name;
2649   SourceLocation Loc;
2650   if (ImportDeclParts(D, DC, LexicalDC, Name, Loc))
2651     return nullptr;
2652 
2653   // Try to find a function in our own ("to") context with the same name, same
2654   // type, and in the same context as the function we're importing.
2655   if (!LexicalDC->isFunctionOrMethod()) {
2656     SmallVector<NamedDecl *, 4> ConflictingDecls;
2657     unsigned IDNS = Decl::IDNS_Ordinary;
2658     SmallVector<NamedDecl *, 2> FoundDecls;
2659     DC->localUncachedLookup(Name, FoundDecls);
2660     for (unsigned I = 0, N = FoundDecls.size(); I != N; ++I) {
2661       if (!FoundDecls[I]->isInIdentifierNamespace(IDNS))
2662         continue;
2663 
2664       if (FunctionDecl *FoundFunction = dyn_cast<FunctionDecl>(FoundDecls[I])) {
2665         if (FoundFunction->hasExternalFormalLinkage() &&
2666             D->hasExternalFormalLinkage()) {
2667           if (Importer.IsStructurallyEquivalent(D->getType(),
2668                                                 FoundFunction->getType())) {
2669             // FIXME: Actually try to merge the body and other attributes.
2670             return Importer.Imported(D, FoundFunction);
2671           }
2672 
2673           // FIXME: Check for overloading more carefully, e.g., by boosting
2674           // Sema::IsOverload out to the AST library.
2675 
2676           // Function overloading is okay in C++.
2677           if (Importer.getToContext().getLangOpts().CPlusPlus)
2678             continue;
2679 
2680           // Complain about inconsistent function types.
2681           Importer.ToDiag(Loc, diag::err_odr_function_type_inconsistent)
2682             << Name << D->getType() << FoundFunction->getType();
2683           Importer.ToDiag(FoundFunction->getLocation(),
2684                           diag::note_odr_value_here)
2685             << FoundFunction->getType();
2686         }
2687       }
2688 
2689       ConflictingDecls.push_back(FoundDecls[I]);
2690     }
2691 
2692     if (!ConflictingDecls.empty()) {
2693       Name = Importer.HandleNameConflict(Name, DC, IDNS,
2694                                          ConflictingDecls.data(),
2695                                          ConflictingDecls.size());
2696       if (!Name)
2697         return nullptr;
2698     }
2699   }
2700 
2701   DeclarationNameInfo NameInfo(Name, Loc);
2702   // Import additional name location/type info.
2703   ImportDeclarationNameLoc(D->getNameInfo(), NameInfo);
2704 
2705   QualType FromTy = D->getType();
2706   bool usedDifferentExceptionSpec = false;
2707 
2708   if (const FunctionProtoType *
2709         FromFPT = D->getType()->getAs<FunctionProtoType>()) {
2710     FunctionProtoType::ExtProtoInfo FromEPI = FromFPT->getExtProtoInfo();
2711     // FunctionProtoType::ExtProtoInfo's ExceptionSpecDecl can point to the
2712     // FunctionDecl that we are importing the FunctionProtoType for.
2713     // To avoid an infinite recursion when importing, create the FunctionDecl
2714     // with a simplified function type and update it afterwards.
2715     if (FromEPI.ExceptionSpec.SourceDecl ||
2716         FromEPI.ExceptionSpec.SourceTemplate ||
2717         FromEPI.ExceptionSpec.NoexceptExpr) {
2718       FunctionProtoType::ExtProtoInfo DefaultEPI;
2719       FromTy = Importer.getFromContext().getFunctionType(
2720           FromFPT->getReturnType(), FromFPT->getParamTypes(), DefaultEPI);
2721       usedDifferentExceptionSpec = true;
2722     }
2723   }
2724 
2725   // Import the type.
2726   QualType T = Importer.Import(FromTy);
2727   if (T.isNull())
2728     return nullptr;
2729 
2730   // Import the function parameters.
2731   SmallVector<ParmVarDecl *, 8> Parameters;
2732   for (auto P : D->params()) {
2733     ParmVarDecl *ToP = cast_or_null<ParmVarDecl>(Importer.Import(P));
2734     if (!ToP)
2735       return nullptr;
2736 
2737     Parameters.push_back(ToP);
2738   }
2739 
2740   // Create the imported function.
2741   TypeSourceInfo *TInfo = Importer.Import(D->getTypeSourceInfo());
2742   FunctionDecl *ToFunction = nullptr;
2743   if (CXXConstructorDecl *FromConstructor = dyn_cast<CXXConstructorDecl>(D)) {
2744     ToFunction = CXXConstructorDecl::Create(Importer.getToContext(),
2745                                             cast<CXXRecordDecl>(DC),
2746                                             D->getInnerLocStart(),
2747                                             NameInfo, T, TInfo,
2748                                             FromConstructor->isExplicit(),
2749                                             D->isInlineSpecified(),
2750                                             D->isImplicit(),
2751                                             D->isConstexpr());
2752   } else if (isa<CXXDestructorDecl>(D)) {
2753     ToFunction = CXXDestructorDecl::Create(Importer.getToContext(),
2754                                            cast<CXXRecordDecl>(DC),
2755                                            D->getInnerLocStart(),
2756                                            NameInfo, T, TInfo,
2757                                            D->isInlineSpecified(),
2758                                            D->isImplicit());
2759   } else if (CXXConversionDecl *FromConversion
2760                                            = dyn_cast<CXXConversionDecl>(D)) {
2761     ToFunction = CXXConversionDecl::Create(Importer.getToContext(),
2762                                            cast<CXXRecordDecl>(DC),
2763                                            D->getInnerLocStart(),
2764                                            NameInfo, T, TInfo,
2765                                            D->isInlineSpecified(),
2766                                            FromConversion->isExplicit(),
2767                                            D->isConstexpr(),
2768                                            Importer.Import(D->getLocEnd()));
2769   } else if (CXXMethodDecl *Method = dyn_cast<CXXMethodDecl>(D)) {
2770     ToFunction = CXXMethodDecl::Create(Importer.getToContext(),
2771                                        cast<CXXRecordDecl>(DC),
2772                                        D->getInnerLocStart(),
2773                                        NameInfo, T, TInfo,
2774                                        Method->getStorageClass(),
2775                                        Method->isInlineSpecified(),
2776                                        D->isConstexpr(),
2777                                        Importer.Import(D->getLocEnd()));
2778   } else {
2779     ToFunction = FunctionDecl::Create(Importer.getToContext(), DC,
2780                                       D->getInnerLocStart(),
2781                                       NameInfo, T, TInfo, D->getStorageClass(),
2782                                       D->isInlineSpecified(),
2783                                       D->hasWrittenPrototype(),
2784                                       D->isConstexpr());
2785   }
2786 
2787   // Import the qualifier, if any.
2788   ToFunction->setQualifierInfo(Importer.Import(D->getQualifierLoc()));
2789   ToFunction->setAccess(D->getAccess());
2790   ToFunction->setLexicalDeclContext(LexicalDC);
2791   ToFunction->setVirtualAsWritten(D->isVirtualAsWritten());
2792   ToFunction->setTrivial(D->isTrivial());
2793   ToFunction->setPure(D->isPure());
2794   Importer.Imported(D, ToFunction);
2795 
2796   // Set the parameters.
2797   for (unsigned I = 0, N = Parameters.size(); I != N; ++I) {
2798     Parameters[I]->setOwningFunction(ToFunction);
2799     ToFunction->addDeclInternal(Parameters[I]);
2800   }
2801   ToFunction->setParams(Parameters);
2802 
2803   if (usedDifferentExceptionSpec) {
2804     // Update FunctionProtoType::ExtProtoInfo.
2805     QualType T = Importer.Import(D->getType());
2806     if (T.isNull())
2807       return nullptr;
2808     ToFunction->setType(T);
2809   }
2810 
2811   // FIXME: Other bits to merge?
2812 
2813   // Add this function to the lexical context.
2814   LexicalDC->addDeclInternal(ToFunction);
2815 
2816   return ToFunction;
2817 }
2818 
2819 Decl *ASTNodeImporter::VisitCXXMethodDecl(CXXMethodDecl *D) {
2820   return VisitFunctionDecl(D);
2821 }
2822 
2823 Decl *ASTNodeImporter::VisitCXXConstructorDecl(CXXConstructorDecl *D) {
2824   return VisitCXXMethodDecl(D);
2825 }
2826 
2827 Decl *ASTNodeImporter::VisitCXXDestructorDecl(CXXDestructorDecl *D) {
2828   return VisitCXXMethodDecl(D);
2829 }
2830 
2831 Decl *ASTNodeImporter::VisitCXXConversionDecl(CXXConversionDecl *D) {
2832   return VisitCXXMethodDecl(D);
2833 }
2834 
2835 static unsigned getFieldIndex(Decl *F) {
2836   RecordDecl *Owner = dyn_cast<RecordDecl>(F->getDeclContext());
2837   if (!Owner)
2838     return 0;
2839 
2840   unsigned Index = 1;
2841   for (const auto *D : Owner->noload_decls()) {
2842     if (D == F)
2843       return Index;
2844 
2845     if (isa<FieldDecl>(*D) || isa<IndirectFieldDecl>(*D))
2846       ++Index;
2847   }
2848 
2849   return Index;
2850 }
2851 
2852 Decl *ASTNodeImporter::VisitFieldDecl(FieldDecl *D) {
2853   // Import the major distinguishing characteristics of a variable.
2854   DeclContext *DC, *LexicalDC;
2855   DeclarationName Name;
2856   SourceLocation Loc;
2857   if (ImportDeclParts(D, DC, LexicalDC, Name, Loc))
2858     return nullptr;
2859 
2860   // Determine whether we've already imported this field.
2861   SmallVector<NamedDecl *, 2> FoundDecls;
2862   DC->localUncachedLookup(Name, FoundDecls);
2863   for (unsigned I = 0, N = FoundDecls.size(); I != N; ++I) {
2864     if (FieldDecl *FoundField = dyn_cast<FieldDecl>(FoundDecls[I])) {
2865       // For anonymous fields, match up by index.
2866       if (!Name && getFieldIndex(D) != getFieldIndex(FoundField))
2867         continue;
2868 
2869       if (Importer.IsStructurallyEquivalent(D->getType(),
2870                                             FoundField->getType())) {
2871         Importer.Imported(D, FoundField);
2872         return FoundField;
2873       }
2874 
2875       Importer.ToDiag(Loc, diag::err_odr_field_type_inconsistent)
2876         << Name << D->getType() << FoundField->getType();
2877       Importer.ToDiag(FoundField->getLocation(), diag::note_odr_value_here)
2878         << FoundField->getType();
2879       return nullptr;
2880     }
2881   }
2882 
2883   // Import the type.
2884   QualType T = Importer.Import(D->getType());
2885   if (T.isNull())
2886     return nullptr;
2887 
2888   TypeSourceInfo *TInfo = Importer.Import(D->getTypeSourceInfo());
2889   Expr *BitWidth = Importer.Import(D->getBitWidth());
2890   if (!BitWidth && D->getBitWidth())
2891     return nullptr;
2892 
2893   FieldDecl *ToField = FieldDecl::Create(Importer.getToContext(), DC,
2894                                          Importer.Import(D->getInnerLocStart()),
2895                                          Loc, Name.getAsIdentifierInfo(),
2896                                          T, TInfo, BitWidth, D->isMutable(),
2897                                          D->getInClassInitStyle());
2898   ToField->setAccess(D->getAccess());
2899   ToField->setLexicalDeclContext(LexicalDC);
2900   if (ToField->hasInClassInitializer())
2901     ToField->setInClassInitializer(D->getInClassInitializer());
2902   ToField->setImplicit(D->isImplicit());
2903   Importer.Imported(D, ToField);
2904   LexicalDC->addDeclInternal(ToField);
2905   return ToField;
2906 }
2907 
2908 Decl *ASTNodeImporter::VisitIndirectFieldDecl(IndirectFieldDecl *D) {
2909   // Import the major distinguishing characteristics of a variable.
2910   DeclContext *DC, *LexicalDC;
2911   DeclarationName Name;
2912   SourceLocation Loc;
2913   if (ImportDeclParts(D, DC, LexicalDC, Name, Loc))
2914     return nullptr;
2915 
2916   // Determine whether we've already imported this field.
2917   SmallVector<NamedDecl *, 2> FoundDecls;
2918   DC->localUncachedLookup(Name, FoundDecls);
2919   for (unsigned I = 0, N = FoundDecls.size(); I != N; ++I) {
2920     if (IndirectFieldDecl *FoundField
2921                                 = dyn_cast<IndirectFieldDecl>(FoundDecls[I])) {
2922       // For anonymous indirect fields, match up by index.
2923       if (!Name && getFieldIndex(D) != getFieldIndex(FoundField))
2924         continue;
2925 
2926       if (Importer.IsStructurallyEquivalent(D->getType(),
2927                                             FoundField->getType(),
2928                                             !Name.isEmpty())) {
2929         Importer.Imported(D, FoundField);
2930         return FoundField;
2931       }
2932 
2933       // If there are more anonymous fields to check, continue.
2934       if (!Name && I < N-1)
2935         continue;
2936 
2937       Importer.ToDiag(Loc, diag::err_odr_field_type_inconsistent)
2938         << Name << D->getType() << FoundField->getType();
2939       Importer.ToDiag(FoundField->getLocation(), diag::note_odr_value_here)
2940         << FoundField->getType();
2941       return nullptr;
2942     }
2943   }
2944 
2945   // Import the type.
2946   QualType T = Importer.Import(D->getType());
2947   if (T.isNull())
2948     return nullptr;
2949 
2950   NamedDecl **NamedChain =
2951     new (Importer.getToContext())NamedDecl*[D->getChainingSize()];
2952 
2953   unsigned i = 0;
2954   for (auto *PI : D->chain()) {
2955     Decl *D = Importer.Import(PI);
2956     if (!D)
2957       return nullptr;
2958     NamedChain[i++] = cast<NamedDecl>(D);
2959   }
2960 
2961   IndirectFieldDecl *ToIndirectField = IndirectFieldDecl::Create(
2962       Importer.getToContext(), DC, Loc, Name.getAsIdentifierInfo(), T,
2963       NamedChain, D->getChainingSize());
2964 
2965   for (const auto *Attr : D->attrs())
2966     ToIndirectField->addAttr(Attr->clone(Importer.getToContext()));
2967 
2968   ToIndirectField->setAccess(D->getAccess());
2969   ToIndirectField->setLexicalDeclContext(LexicalDC);
2970   Importer.Imported(D, ToIndirectField);
2971   LexicalDC->addDeclInternal(ToIndirectField);
2972   return ToIndirectField;
2973 }
2974 
2975 Decl *ASTNodeImporter::VisitObjCIvarDecl(ObjCIvarDecl *D) {
2976   // Import the major distinguishing characteristics of an ivar.
2977   DeclContext *DC, *LexicalDC;
2978   DeclarationName Name;
2979   SourceLocation Loc;
2980   if (ImportDeclParts(D, DC, LexicalDC, Name, Loc))
2981     return nullptr;
2982 
2983   // Determine whether we've already imported this ivar
2984   SmallVector<NamedDecl *, 2> FoundDecls;
2985   DC->localUncachedLookup(Name, FoundDecls);
2986   for (unsigned I = 0, N = FoundDecls.size(); I != N; ++I) {
2987     if (ObjCIvarDecl *FoundIvar = dyn_cast<ObjCIvarDecl>(FoundDecls[I])) {
2988       if (Importer.IsStructurallyEquivalent(D->getType(),
2989                                             FoundIvar->getType())) {
2990         Importer.Imported(D, FoundIvar);
2991         return FoundIvar;
2992       }
2993 
2994       Importer.ToDiag(Loc, diag::err_odr_ivar_type_inconsistent)
2995         << Name << D->getType() << FoundIvar->getType();
2996       Importer.ToDiag(FoundIvar->getLocation(), diag::note_odr_value_here)
2997         << FoundIvar->getType();
2998       return nullptr;
2999     }
3000   }
3001 
3002   // Import the type.
3003   QualType T = Importer.Import(D->getType());
3004   if (T.isNull())
3005     return nullptr;
3006 
3007   TypeSourceInfo *TInfo = Importer.Import(D->getTypeSourceInfo());
3008   Expr *BitWidth = Importer.Import(D->getBitWidth());
3009   if (!BitWidth && D->getBitWidth())
3010     return nullptr;
3011 
3012   ObjCIvarDecl *ToIvar = ObjCIvarDecl::Create(Importer.getToContext(),
3013                                               cast<ObjCContainerDecl>(DC),
3014                                        Importer.Import(D->getInnerLocStart()),
3015                                               Loc, Name.getAsIdentifierInfo(),
3016                                               T, TInfo, D->getAccessControl(),
3017                                               BitWidth, D->getSynthesize());
3018   ToIvar->setLexicalDeclContext(LexicalDC);
3019   Importer.Imported(D, ToIvar);
3020   LexicalDC->addDeclInternal(ToIvar);
3021   return ToIvar;
3022 
3023 }
3024 
3025 Decl *ASTNodeImporter::VisitVarDecl(VarDecl *D) {
3026   // Import the major distinguishing characteristics of a variable.
3027   DeclContext *DC, *LexicalDC;
3028   DeclarationName Name;
3029   SourceLocation Loc;
3030   if (ImportDeclParts(D, DC, LexicalDC, Name, Loc))
3031     return nullptr;
3032 
3033   // Try to find a variable in our own ("to") context with the same name and
3034   // in the same context as the variable we're importing.
3035   if (D->isFileVarDecl()) {
3036     VarDecl *MergeWithVar = nullptr;
3037     SmallVector<NamedDecl *, 4> ConflictingDecls;
3038     unsigned IDNS = Decl::IDNS_Ordinary;
3039     SmallVector<NamedDecl *, 2> FoundDecls;
3040     DC->localUncachedLookup(Name, FoundDecls);
3041     for (unsigned I = 0, N = FoundDecls.size(); I != N; ++I) {
3042       if (!FoundDecls[I]->isInIdentifierNamespace(IDNS))
3043         continue;
3044 
3045       if (VarDecl *FoundVar = dyn_cast<VarDecl>(FoundDecls[I])) {
3046         // We have found a variable that we may need to merge with. Check it.
3047         if (FoundVar->hasExternalFormalLinkage() &&
3048             D->hasExternalFormalLinkage()) {
3049           if (Importer.IsStructurallyEquivalent(D->getType(),
3050                                                 FoundVar->getType())) {
3051             MergeWithVar = FoundVar;
3052             break;
3053           }
3054 
3055           const ArrayType *FoundArray
3056             = Importer.getToContext().getAsArrayType(FoundVar->getType());
3057           const ArrayType *TArray
3058             = Importer.getToContext().getAsArrayType(D->getType());
3059           if (FoundArray && TArray) {
3060             if (isa<IncompleteArrayType>(FoundArray) &&
3061                 isa<ConstantArrayType>(TArray)) {
3062               // Import the type.
3063               QualType T = Importer.Import(D->getType());
3064               if (T.isNull())
3065                 return nullptr;
3066 
3067               FoundVar->setType(T);
3068               MergeWithVar = FoundVar;
3069               break;
3070             } else if (isa<IncompleteArrayType>(TArray) &&
3071                        isa<ConstantArrayType>(FoundArray)) {
3072               MergeWithVar = FoundVar;
3073               break;
3074             }
3075           }
3076 
3077           Importer.ToDiag(Loc, diag::err_odr_variable_type_inconsistent)
3078             << Name << D->getType() << FoundVar->getType();
3079           Importer.ToDiag(FoundVar->getLocation(), diag::note_odr_value_here)
3080             << FoundVar->getType();
3081         }
3082       }
3083 
3084       ConflictingDecls.push_back(FoundDecls[I]);
3085     }
3086 
3087     if (MergeWithVar) {
3088       // An equivalent variable with external linkage has been found. Link
3089       // the two declarations, then merge them.
3090       Importer.Imported(D, MergeWithVar);
3091 
3092       if (VarDecl *DDef = D->getDefinition()) {
3093         if (VarDecl *ExistingDef = MergeWithVar->getDefinition()) {
3094           Importer.ToDiag(ExistingDef->getLocation(),
3095                           diag::err_odr_variable_multiple_def)
3096             << Name;
3097           Importer.FromDiag(DDef->getLocation(), diag::note_odr_defined_here);
3098         } else {
3099           Expr *Init = Importer.Import(DDef->getInit());
3100           MergeWithVar->setInit(Init);
3101           if (DDef->isInitKnownICE()) {
3102             EvaluatedStmt *Eval = MergeWithVar->ensureEvaluatedStmt();
3103             Eval->CheckedICE = true;
3104             Eval->IsICE = DDef->isInitICE();
3105           }
3106         }
3107       }
3108 
3109       return MergeWithVar;
3110     }
3111 
3112     if (!ConflictingDecls.empty()) {
3113       Name = Importer.HandleNameConflict(Name, DC, IDNS,
3114                                          ConflictingDecls.data(),
3115                                          ConflictingDecls.size());
3116       if (!Name)
3117         return nullptr;
3118     }
3119   }
3120 
3121   // Import the type.
3122   QualType T = Importer.Import(D->getType());
3123   if (T.isNull())
3124     return nullptr;
3125 
3126   // Create the imported variable.
3127   TypeSourceInfo *TInfo = Importer.Import(D->getTypeSourceInfo());
3128   VarDecl *ToVar = VarDecl::Create(Importer.getToContext(), DC,
3129                                    Importer.Import(D->getInnerLocStart()),
3130                                    Loc, Name.getAsIdentifierInfo(),
3131                                    T, TInfo,
3132                                    D->getStorageClass());
3133   ToVar->setQualifierInfo(Importer.Import(D->getQualifierLoc()));
3134   ToVar->setAccess(D->getAccess());
3135   ToVar->setLexicalDeclContext(LexicalDC);
3136   Importer.Imported(D, ToVar);
3137   LexicalDC->addDeclInternal(ToVar);
3138 
3139   // Merge the initializer.
3140   if (ImportDefinition(D, ToVar))
3141     return nullptr;
3142 
3143   return ToVar;
3144 }
3145 
3146 Decl *ASTNodeImporter::VisitImplicitParamDecl(ImplicitParamDecl *D) {
3147   // Parameters are created in the translation unit's context, then moved
3148   // into the function declaration's context afterward.
3149   DeclContext *DC = Importer.getToContext().getTranslationUnitDecl();
3150 
3151   // Import the name of this declaration.
3152   DeclarationName Name = Importer.Import(D->getDeclName());
3153   if (D->getDeclName() && !Name)
3154     return nullptr;
3155 
3156   // Import the location of this declaration.
3157   SourceLocation Loc = Importer.Import(D->getLocation());
3158 
3159   // Import the parameter's type.
3160   QualType T = Importer.Import(D->getType());
3161   if (T.isNull())
3162     return nullptr;
3163 
3164   // Create the imported parameter.
3165   ImplicitParamDecl *ToParm
3166     = ImplicitParamDecl::Create(Importer.getToContext(), DC,
3167                                 Loc, Name.getAsIdentifierInfo(),
3168                                 T);
3169   return Importer.Imported(D, ToParm);
3170 }
3171 
3172 Decl *ASTNodeImporter::VisitParmVarDecl(ParmVarDecl *D) {
3173   // Parameters are created in the translation unit's context, then moved
3174   // into the function declaration's context afterward.
3175   DeclContext *DC = Importer.getToContext().getTranslationUnitDecl();
3176 
3177   // Import the name of this declaration.
3178   DeclarationName Name = Importer.Import(D->getDeclName());
3179   if (D->getDeclName() && !Name)
3180     return nullptr;
3181 
3182   // Import the location of this declaration.
3183   SourceLocation Loc = Importer.Import(D->getLocation());
3184 
3185   // Import the parameter's type.
3186   QualType T = Importer.Import(D->getType());
3187   if (T.isNull())
3188     return nullptr;
3189 
3190   // Create the imported parameter.
3191   TypeSourceInfo *TInfo = Importer.Import(D->getTypeSourceInfo());
3192   ParmVarDecl *ToParm = ParmVarDecl::Create(Importer.getToContext(), DC,
3193                                      Importer.Import(D->getInnerLocStart()),
3194                                             Loc, Name.getAsIdentifierInfo(),
3195                                             T, TInfo, D->getStorageClass(),
3196                                             /*FIXME: Default argument*/nullptr);
3197   ToParm->setHasInheritedDefaultArg(D->hasInheritedDefaultArg());
3198   return Importer.Imported(D, ToParm);
3199 }
3200 
3201 Decl *ASTNodeImporter::VisitObjCMethodDecl(ObjCMethodDecl *D) {
3202   // Import the major distinguishing characteristics of a method.
3203   DeclContext *DC, *LexicalDC;
3204   DeclarationName Name;
3205   SourceLocation Loc;
3206   if (ImportDeclParts(D, DC, LexicalDC, Name, Loc))
3207     return nullptr;
3208 
3209   SmallVector<NamedDecl *, 2> FoundDecls;
3210   DC->localUncachedLookup(Name, FoundDecls);
3211   for (unsigned I = 0, N = FoundDecls.size(); I != N; ++I) {
3212     if (ObjCMethodDecl *FoundMethod = dyn_cast<ObjCMethodDecl>(FoundDecls[I])) {
3213       if (FoundMethod->isInstanceMethod() != D->isInstanceMethod())
3214         continue;
3215 
3216       // Check return types.
3217       if (!Importer.IsStructurallyEquivalent(D->getReturnType(),
3218                                              FoundMethod->getReturnType())) {
3219         Importer.ToDiag(Loc, diag::err_odr_objc_method_result_type_inconsistent)
3220             << D->isInstanceMethod() << Name << D->getReturnType()
3221             << FoundMethod->getReturnType();
3222         Importer.ToDiag(FoundMethod->getLocation(),
3223                         diag::note_odr_objc_method_here)
3224           << D->isInstanceMethod() << Name;
3225         return nullptr;
3226       }
3227 
3228       // Check the number of parameters.
3229       if (D->param_size() != FoundMethod->param_size()) {
3230         Importer.ToDiag(Loc, diag::err_odr_objc_method_num_params_inconsistent)
3231           << D->isInstanceMethod() << Name
3232           << D->param_size() << FoundMethod->param_size();
3233         Importer.ToDiag(FoundMethod->getLocation(),
3234                         diag::note_odr_objc_method_here)
3235           << D->isInstanceMethod() << Name;
3236         return nullptr;
3237       }
3238 
3239       // Check parameter types.
3240       for (ObjCMethodDecl::param_iterator P = D->param_begin(),
3241              PEnd = D->param_end(), FoundP = FoundMethod->param_begin();
3242            P != PEnd; ++P, ++FoundP) {
3243         if (!Importer.IsStructurallyEquivalent((*P)->getType(),
3244                                                (*FoundP)->getType())) {
3245           Importer.FromDiag((*P)->getLocation(),
3246                             diag::err_odr_objc_method_param_type_inconsistent)
3247             << D->isInstanceMethod() << Name
3248             << (*P)->getType() << (*FoundP)->getType();
3249           Importer.ToDiag((*FoundP)->getLocation(), diag::note_odr_value_here)
3250             << (*FoundP)->getType();
3251           return nullptr;
3252         }
3253       }
3254 
3255       // Check variadic/non-variadic.
3256       // Check the number of parameters.
3257       if (D->isVariadic() != FoundMethod->isVariadic()) {
3258         Importer.ToDiag(Loc, diag::err_odr_objc_method_variadic_inconsistent)
3259           << D->isInstanceMethod() << Name;
3260         Importer.ToDiag(FoundMethod->getLocation(),
3261                         diag::note_odr_objc_method_here)
3262           << D->isInstanceMethod() << Name;
3263         return nullptr;
3264       }
3265 
3266       // FIXME: Any other bits we need to merge?
3267       return Importer.Imported(D, FoundMethod);
3268     }
3269   }
3270 
3271   // Import the result type.
3272   QualType ResultTy = Importer.Import(D->getReturnType());
3273   if (ResultTy.isNull())
3274     return nullptr;
3275 
3276   TypeSourceInfo *ReturnTInfo = Importer.Import(D->getReturnTypeSourceInfo());
3277 
3278   ObjCMethodDecl *ToMethod = ObjCMethodDecl::Create(
3279       Importer.getToContext(), Loc, Importer.Import(D->getLocEnd()),
3280       Name.getObjCSelector(), ResultTy, ReturnTInfo, DC, D->isInstanceMethod(),
3281       D->isVariadic(), D->isPropertyAccessor(), D->isImplicit(), D->isDefined(),
3282       D->getImplementationControl(), D->hasRelatedResultType());
3283 
3284   // FIXME: When we decide to merge method definitions, we'll need to
3285   // deal with implicit parameters.
3286 
3287   // Import the parameters
3288   SmallVector<ParmVarDecl *, 5> ToParams;
3289   for (auto *FromP : D->params()) {
3290     ParmVarDecl *ToP = cast_or_null<ParmVarDecl>(Importer.Import(FromP));
3291     if (!ToP)
3292       return nullptr;
3293 
3294     ToParams.push_back(ToP);
3295   }
3296 
3297   // Set the parameters.
3298   for (unsigned I = 0, N = ToParams.size(); I != N; ++I) {
3299     ToParams[I]->setOwningFunction(ToMethod);
3300     ToMethod->addDeclInternal(ToParams[I]);
3301   }
3302   SmallVector<SourceLocation, 12> SelLocs;
3303   D->getSelectorLocs(SelLocs);
3304   ToMethod->setMethodParams(Importer.getToContext(), ToParams, SelLocs);
3305 
3306   ToMethod->setLexicalDeclContext(LexicalDC);
3307   Importer.Imported(D, ToMethod);
3308   LexicalDC->addDeclInternal(ToMethod);
3309   return ToMethod;
3310 }
3311 
3312 Decl *ASTNodeImporter::VisitObjCCategoryDecl(ObjCCategoryDecl *D) {
3313   // Import the major distinguishing characteristics of a category.
3314   DeclContext *DC, *LexicalDC;
3315   DeclarationName Name;
3316   SourceLocation Loc;
3317   if (ImportDeclParts(D, DC, LexicalDC, Name, Loc))
3318     return nullptr;
3319 
3320   ObjCInterfaceDecl *ToInterface
3321     = cast_or_null<ObjCInterfaceDecl>(Importer.Import(D->getClassInterface()));
3322   if (!ToInterface)
3323     return nullptr;
3324 
3325   // Determine if we've already encountered this category.
3326   ObjCCategoryDecl *MergeWithCategory
3327     = ToInterface->FindCategoryDeclaration(Name.getAsIdentifierInfo());
3328   ObjCCategoryDecl *ToCategory = MergeWithCategory;
3329   if (!ToCategory) {
3330     ToCategory = ObjCCategoryDecl::Create(Importer.getToContext(), DC,
3331                                           Importer.Import(D->getAtStartLoc()),
3332                                           Loc,
3333                                        Importer.Import(D->getCategoryNameLoc()),
3334                                           Name.getAsIdentifierInfo(),
3335                                           ToInterface,
3336                                        Importer.Import(D->getIvarLBraceLoc()),
3337                                        Importer.Import(D->getIvarRBraceLoc()));
3338     ToCategory->setLexicalDeclContext(LexicalDC);
3339     LexicalDC->addDeclInternal(ToCategory);
3340     Importer.Imported(D, ToCategory);
3341 
3342     // Import protocols
3343     SmallVector<ObjCProtocolDecl *, 4> Protocols;
3344     SmallVector<SourceLocation, 4> ProtocolLocs;
3345     ObjCCategoryDecl::protocol_loc_iterator FromProtoLoc
3346       = D->protocol_loc_begin();
3347     for (ObjCCategoryDecl::protocol_iterator FromProto = D->protocol_begin(),
3348                                           FromProtoEnd = D->protocol_end();
3349          FromProto != FromProtoEnd;
3350          ++FromProto, ++FromProtoLoc) {
3351       ObjCProtocolDecl *ToProto
3352         = cast_or_null<ObjCProtocolDecl>(Importer.Import(*FromProto));
3353       if (!ToProto)
3354         return nullptr;
3355       Protocols.push_back(ToProto);
3356       ProtocolLocs.push_back(Importer.Import(*FromProtoLoc));
3357     }
3358 
3359     // FIXME: If we're merging, make sure that the protocol list is the same.
3360     ToCategory->setProtocolList(Protocols.data(), Protocols.size(),
3361                                 ProtocolLocs.data(), Importer.getToContext());
3362 
3363   } else {
3364     Importer.Imported(D, ToCategory);
3365   }
3366 
3367   // Import all of the members of this category.
3368   ImportDeclContext(D);
3369 
3370   // If we have an implementation, import it as well.
3371   if (D->getImplementation()) {
3372     ObjCCategoryImplDecl *Impl
3373       = cast_or_null<ObjCCategoryImplDecl>(
3374                                        Importer.Import(D->getImplementation()));
3375     if (!Impl)
3376       return nullptr;
3377 
3378     ToCategory->setImplementation(Impl);
3379   }
3380 
3381   return ToCategory;
3382 }
3383 
3384 bool ASTNodeImporter::ImportDefinition(ObjCProtocolDecl *From,
3385                                        ObjCProtocolDecl *To,
3386                                        ImportDefinitionKind Kind) {
3387   if (To->getDefinition()) {
3388     if (shouldForceImportDeclContext(Kind))
3389       ImportDeclContext(From);
3390     return false;
3391   }
3392 
3393   // Start the protocol definition
3394   To->startDefinition();
3395 
3396   // Import protocols
3397   SmallVector<ObjCProtocolDecl *, 4> Protocols;
3398   SmallVector<SourceLocation, 4> ProtocolLocs;
3399   ObjCProtocolDecl::protocol_loc_iterator
3400   FromProtoLoc = From->protocol_loc_begin();
3401   for (ObjCProtocolDecl::protocol_iterator FromProto = From->protocol_begin(),
3402                                         FromProtoEnd = From->protocol_end();
3403        FromProto != FromProtoEnd;
3404        ++FromProto, ++FromProtoLoc) {
3405     ObjCProtocolDecl *ToProto
3406       = cast_or_null<ObjCProtocolDecl>(Importer.Import(*FromProto));
3407     if (!ToProto)
3408       return true;
3409     Protocols.push_back(ToProto);
3410     ProtocolLocs.push_back(Importer.Import(*FromProtoLoc));
3411   }
3412 
3413   // FIXME: If we're merging, make sure that the protocol list is the same.
3414   To->setProtocolList(Protocols.data(), Protocols.size(),
3415                       ProtocolLocs.data(), Importer.getToContext());
3416 
3417   if (shouldForceImportDeclContext(Kind)) {
3418     // Import all of the members of this protocol.
3419     ImportDeclContext(From, /*ForceImport=*/true);
3420   }
3421   return false;
3422 }
3423 
3424 Decl *ASTNodeImporter::VisitObjCProtocolDecl(ObjCProtocolDecl *D) {
3425   // If this protocol has a definition in the translation unit we're coming
3426   // from, but this particular declaration is not that definition, import the
3427   // definition and map to that.
3428   ObjCProtocolDecl *Definition = D->getDefinition();
3429   if (Definition && Definition != D) {
3430     Decl *ImportedDef = Importer.Import(Definition);
3431     if (!ImportedDef)
3432       return nullptr;
3433 
3434     return Importer.Imported(D, ImportedDef);
3435   }
3436 
3437   // Import the major distinguishing characteristics of a protocol.
3438   DeclContext *DC, *LexicalDC;
3439   DeclarationName Name;
3440   SourceLocation Loc;
3441   if (ImportDeclParts(D, DC, LexicalDC, Name, Loc))
3442     return nullptr;
3443 
3444   ObjCProtocolDecl *MergeWithProtocol = nullptr;
3445   SmallVector<NamedDecl *, 2> FoundDecls;
3446   DC->localUncachedLookup(Name, FoundDecls);
3447   for (unsigned I = 0, N = FoundDecls.size(); I != N; ++I) {
3448     if (!FoundDecls[I]->isInIdentifierNamespace(Decl::IDNS_ObjCProtocol))
3449       continue;
3450 
3451     if ((MergeWithProtocol = dyn_cast<ObjCProtocolDecl>(FoundDecls[I])))
3452       break;
3453   }
3454 
3455   ObjCProtocolDecl *ToProto = MergeWithProtocol;
3456   if (!ToProto) {
3457     ToProto = ObjCProtocolDecl::Create(Importer.getToContext(), DC,
3458                                        Name.getAsIdentifierInfo(), Loc,
3459                                        Importer.Import(D->getAtStartLoc()),
3460                                        /*PrevDecl=*/nullptr);
3461     ToProto->setLexicalDeclContext(LexicalDC);
3462     LexicalDC->addDeclInternal(ToProto);
3463   }
3464 
3465   Importer.Imported(D, ToProto);
3466 
3467   if (D->isThisDeclarationADefinition() && ImportDefinition(D, ToProto))
3468     return nullptr;
3469 
3470   return ToProto;
3471 }
3472 
3473 bool ASTNodeImporter::ImportDefinition(ObjCInterfaceDecl *From,
3474                                        ObjCInterfaceDecl *To,
3475                                        ImportDefinitionKind Kind) {
3476   if (To->getDefinition()) {
3477     // Check consistency of superclass.
3478     ObjCInterfaceDecl *FromSuper = From->getSuperClass();
3479     if (FromSuper) {
3480       FromSuper = cast_or_null<ObjCInterfaceDecl>(Importer.Import(FromSuper));
3481       if (!FromSuper)
3482         return true;
3483     }
3484 
3485     ObjCInterfaceDecl *ToSuper = To->getSuperClass();
3486     if ((bool)FromSuper != (bool)ToSuper ||
3487         (FromSuper && !declaresSameEntity(FromSuper, ToSuper))) {
3488       Importer.ToDiag(To->getLocation(),
3489                       diag::err_odr_objc_superclass_inconsistent)
3490         << To->getDeclName();
3491       if (ToSuper)
3492         Importer.ToDiag(To->getSuperClassLoc(), diag::note_odr_objc_superclass)
3493           << To->getSuperClass()->getDeclName();
3494       else
3495         Importer.ToDiag(To->getLocation(),
3496                         diag::note_odr_objc_missing_superclass);
3497       if (From->getSuperClass())
3498         Importer.FromDiag(From->getSuperClassLoc(),
3499                           diag::note_odr_objc_superclass)
3500         << From->getSuperClass()->getDeclName();
3501       else
3502         Importer.FromDiag(From->getLocation(),
3503                           diag::note_odr_objc_missing_superclass);
3504     }
3505 
3506     if (shouldForceImportDeclContext(Kind))
3507       ImportDeclContext(From);
3508     return false;
3509   }
3510 
3511   // Start the definition.
3512   To->startDefinition();
3513 
3514   // If this class has a superclass, import it.
3515   if (From->getSuperClass()) {
3516     ObjCInterfaceDecl *Super = cast_or_null<ObjCInterfaceDecl>(
3517                                  Importer.Import(From->getSuperClass()));
3518     if (!Super)
3519       return true;
3520 
3521     To->setSuperClass(Super);
3522     To->setSuperClassLoc(Importer.Import(From->getSuperClassLoc()));
3523   }
3524 
3525   // Import protocols
3526   SmallVector<ObjCProtocolDecl *, 4> Protocols;
3527   SmallVector<SourceLocation, 4> ProtocolLocs;
3528   ObjCInterfaceDecl::protocol_loc_iterator
3529   FromProtoLoc = From->protocol_loc_begin();
3530 
3531   for (ObjCInterfaceDecl::protocol_iterator FromProto = From->protocol_begin(),
3532                                          FromProtoEnd = From->protocol_end();
3533        FromProto != FromProtoEnd;
3534        ++FromProto, ++FromProtoLoc) {
3535     ObjCProtocolDecl *ToProto
3536       = cast_or_null<ObjCProtocolDecl>(Importer.Import(*FromProto));
3537     if (!ToProto)
3538       return true;
3539     Protocols.push_back(ToProto);
3540     ProtocolLocs.push_back(Importer.Import(*FromProtoLoc));
3541   }
3542 
3543   // FIXME: If we're merging, make sure that the protocol list is the same.
3544   To->setProtocolList(Protocols.data(), Protocols.size(),
3545                       ProtocolLocs.data(), Importer.getToContext());
3546 
3547   // Import categories. When the categories themselves are imported, they'll
3548   // hook themselves into this interface.
3549   for (auto *Cat : From->known_categories())
3550     Importer.Import(Cat);
3551 
3552   // If we have an @implementation, import it as well.
3553   if (From->getImplementation()) {
3554     ObjCImplementationDecl *Impl = cast_or_null<ObjCImplementationDecl>(
3555                                      Importer.Import(From->getImplementation()));
3556     if (!Impl)
3557       return true;
3558 
3559     To->setImplementation(Impl);
3560   }
3561 
3562   if (shouldForceImportDeclContext(Kind)) {
3563     // Import all of the members of this class.
3564     ImportDeclContext(From, /*ForceImport=*/true);
3565   }
3566   return false;
3567 }
3568 
3569 Decl *ASTNodeImporter::VisitObjCInterfaceDecl(ObjCInterfaceDecl *D) {
3570   // If this class has a definition in the translation unit we're coming from,
3571   // but this particular declaration is not that definition, import the
3572   // definition and map to that.
3573   ObjCInterfaceDecl *Definition = D->getDefinition();
3574   if (Definition && Definition != D) {
3575     Decl *ImportedDef = Importer.Import(Definition);
3576     if (!ImportedDef)
3577       return nullptr;
3578 
3579     return Importer.Imported(D, ImportedDef);
3580   }
3581 
3582   // Import the major distinguishing characteristics of an @interface.
3583   DeclContext *DC, *LexicalDC;
3584   DeclarationName Name;
3585   SourceLocation Loc;
3586   if (ImportDeclParts(D, DC, LexicalDC, Name, Loc))
3587     return nullptr;
3588 
3589   // Look for an existing interface with the same name.
3590   ObjCInterfaceDecl *MergeWithIface = nullptr;
3591   SmallVector<NamedDecl *, 2> FoundDecls;
3592   DC->localUncachedLookup(Name, FoundDecls);
3593   for (unsigned I = 0, N = FoundDecls.size(); I != N; ++I) {
3594     if (!FoundDecls[I]->isInIdentifierNamespace(Decl::IDNS_Ordinary))
3595       continue;
3596 
3597     if ((MergeWithIface = dyn_cast<ObjCInterfaceDecl>(FoundDecls[I])))
3598       break;
3599   }
3600 
3601   // Create an interface declaration, if one does not already exist.
3602   ObjCInterfaceDecl *ToIface = MergeWithIface;
3603   if (!ToIface) {
3604     ToIface = ObjCInterfaceDecl::Create(Importer.getToContext(), DC,
3605                                         Importer.Import(D->getAtStartLoc()),
3606                                         Name.getAsIdentifierInfo(),
3607                                         /*PrevDecl=*/nullptr, Loc,
3608                                         D->isImplicitInterfaceDecl());
3609     ToIface->setLexicalDeclContext(LexicalDC);
3610     LexicalDC->addDeclInternal(ToIface);
3611   }
3612   Importer.Imported(D, ToIface);
3613 
3614   if (D->isThisDeclarationADefinition() && ImportDefinition(D, ToIface))
3615     return nullptr;
3616 
3617   return ToIface;
3618 }
3619 
3620 Decl *ASTNodeImporter::VisitObjCCategoryImplDecl(ObjCCategoryImplDecl *D) {
3621   ObjCCategoryDecl *Category = cast_or_null<ObjCCategoryDecl>(
3622                                         Importer.Import(D->getCategoryDecl()));
3623   if (!Category)
3624     return nullptr;
3625 
3626   ObjCCategoryImplDecl *ToImpl = Category->getImplementation();
3627   if (!ToImpl) {
3628     DeclContext *DC = Importer.ImportContext(D->getDeclContext());
3629     if (!DC)
3630       return nullptr;
3631 
3632     SourceLocation CategoryNameLoc = Importer.Import(D->getCategoryNameLoc());
3633     ToImpl = ObjCCategoryImplDecl::Create(Importer.getToContext(), DC,
3634                                           Importer.Import(D->getIdentifier()),
3635                                           Category->getClassInterface(),
3636                                           Importer.Import(D->getLocation()),
3637                                           Importer.Import(D->getAtStartLoc()),
3638                                           CategoryNameLoc);
3639 
3640     DeclContext *LexicalDC = DC;
3641     if (D->getDeclContext() != D->getLexicalDeclContext()) {
3642       LexicalDC = Importer.ImportContext(D->getLexicalDeclContext());
3643       if (!LexicalDC)
3644         return nullptr;
3645 
3646       ToImpl->setLexicalDeclContext(LexicalDC);
3647     }
3648 
3649     LexicalDC->addDeclInternal(ToImpl);
3650     Category->setImplementation(ToImpl);
3651   }
3652 
3653   Importer.Imported(D, ToImpl);
3654   ImportDeclContext(D);
3655   return ToImpl;
3656 }
3657 
3658 Decl *ASTNodeImporter::VisitObjCImplementationDecl(ObjCImplementationDecl *D) {
3659   // Find the corresponding interface.
3660   ObjCInterfaceDecl *Iface = cast_or_null<ObjCInterfaceDecl>(
3661                                        Importer.Import(D->getClassInterface()));
3662   if (!Iface)
3663     return nullptr;
3664 
3665   // Import the superclass, if any.
3666   ObjCInterfaceDecl *Super = nullptr;
3667   if (D->getSuperClass()) {
3668     Super = cast_or_null<ObjCInterfaceDecl>(
3669                                           Importer.Import(D->getSuperClass()));
3670     if (!Super)
3671       return nullptr;
3672   }
3673 
3674   ObjCImplementationDecl *Impl = Iface->getImplementation();
3675   if (!Impl) {
3676     // We haven't imported an implementation yet. Create a new @implementation
3677     // now.
3678     Impl = ObjCImplementationDecl::Create(Importer.getToContext(),
3679                                   Importer.ImportContext(D->getDeclContext()),
3680                                           Iface, Super,
3681                                           Importer.Import(D->getLocation()),
3682                                           Importer.Import(D->getAtStartLoc()),
3683                                           Importer.Import(D->getSuperClassLoc()),
3684                                           Importer.Import(D->getIvarLBraceLoc()),
3685                                           Importer.Import(D->getIvarRBraceLoc()));
3686 
3687     if (D->getDeclContext() != D->getLexicalDeclContext()) {
3688       DeclContext *LexicalDC
3689         = Importer.ImportContext(D->getLexicalDeclContext());
3690       if (!LexicalDC)
3691         return nullptr;
3692       Impl->setLexicalDeclContext(LexicalDC);
3693     }
3694 
3695     // Associate the implementation with the class it implements.
3696     Iface->setImplementation(Impl);
3697     Importer.Imported(D, Iface->getImplementation());
3698   } else {
3699     Importer.Imported(D, Iface->getImplementation());
3700 
3701     // Verify that the existing @implementation has the same superclass.
3702     if ((Super && !Impl->getSuperClass()) ||
3703         (!Super && Impl->getSuperClass()) ||
3704         (Super && Impl->getSuperClass() &&
3705          !declaresSameEntity(Super->getCanonicalDecl(),
3706                              Impl->getSuperClass()))) {
3707       Importer.ToDiag(Impl->getLocation(),
3708                       diag::err_odr_objc_superclass_inconsistent)
3709         << Iface->getDeclName();
3710       // FIXME: It would be nice to have the location of the superclass
3711       // below.
3712       if (Impl->getSuperClass())
3713         Importer.ToDiag(Impl->getLocation(),
3714                         diag::note_odr_objc_superclass)
3715         << Impl->getSuperClass()->getDeclName();
3716       else
3717         Importer.ToDiag(Impl->getLocation(),
3718                         diag::note_odr_objc_missing_superclass);
3719       if (D->getSuperClass())
3720         Importer.FromDiag(D->getLocation(),
3721                           diag::note_odr_objc_superclass)
3722         << D->getSuperClass()->getDeclName();
3723       else
3724         Importer.FromDiag(D->getLocation(),
3725                           diag::note_odr_objc_missing_superclass);
3726       return nullptr;
3727     }
3728   }
3729 
3730   // Import all of the members of this @implementation.
3731   ImportDeclContext(D);
3732 
3733   return Impl;
3734 }
3735 
3736 Decl *ASTNodeImporter::VisitObjCPropertyDecl(ObjCPropertyDecl *D) {
3737   // Import the major distinguishing characteristics of an @property.
3738   DeclContext *DC, *LexicalDC;
3739   DeclarationName Name;
3740   SourceLocation Loc;
3741   if (ImportDeclParts(D, DC, LexicalDC, Name, Loc))
3742     return nullptr;
3743 
3744   // Check whether we have already imported this property.
3745   SmallVector<NamedDecl *, 2> FoundDecls;
3746   DC->localUncachedLookup(Name, FoundDecls);
3747   for (unsigned I = 0, N = FoundDecls.size(); I != N; ++I) {
3748     if (ObjCPropertyDecl *FoundProp
3749                                 = dyn_cast<ObjCPropertyDecl>(FoundDecls[I])) {
3750       // Check property types.
3751       if (!Importer.IsStructurallyEquivalent(D->getType(),
3752                                              FoundProp->getType())) {
3753         Importer.ToDiag(Loc, diag::err_odr_objc_property_type_inconsistent)
3754           << Name << D->getType() << FoundProp->getType();
3755         Importer.ToDiag(FoundProp->getLocation(), diag::note_odr_value_here)
3756           << FoundProp->getType();
3757         return nullptr;
3758       }
3759 
3760       // FIXME: Check property attributes, getters, setters, etc.?
3761 
3762       // Consider these properties to be equivalent.
3763       Importer.Imported(D, FoundProp);
3764       return FoundProp;
3765     }
3766   }
3767 
3768   // Import the type.
3769   TypeSourceInfo *T = Importer.Import(D->getTypeSourceInfo());
3770   if (!T)
3771     return nullptr;
3772 
3773   // Create the new property.
3774   ObjCPropertyDecl *ToProperty
3775     = ObjCPropertyDecl::Create(Importer.getToContext(), DC, Loc,
3776                                Name.getAsIdentifierInfo(),
3777                                Importer.Import(D->getAtLoc()),
3778                                Importer.Import(D->getLParenLoc()),
3779                                T,
3780                                D->getPropertyImplementation());
3781   Importer.Imported(D, ToProperty);
3782   ToProperty->setLexicalDeclContext(LexicalDC);
3783   LexicalDC->addDeclInternal(ToProperty);
3784 
3785   ToProperty->setPropertyAttributes(D->getPropertyAttributes());
3786   ToProperty->setPropertyAttributesAsWritten(
3787                                       D->getPropertyAttributesAsWritten());
3788   ToProperty->setGetterName(Importer.Import(D->getGetterName()));
3789   ToProperty->setSetterName(Importer.Import(D->getSetterName()));
3790   ToProperty->setGetterMethodDecl(
3791      cast_or_null<ObjCMethodDecl>(Importer.Import(D->getGetterMethodDecl())));
3792   ToProperty->setSetterMethodDecl(
3793      cast_or_null<ObjCMethodDecl>(Importer.Import(D->getSetterMethodDecl())));
3794   ToProperty->setPropertyIvarDecl(
3795        cast_or_null<ObjCIvarDecl>(Importer.Import(D->getPropertyIvarDecl())));
3796   return ToProperty;
3797 }
3798 
3799 Decl *ASTNodeImporter::VisitObjCPropertyImplDecl(ObjCPropertyImplDecl *D) {
3800   ObjCPropertyDecl *Property = cast_or_null<ObjCPropertyDecl>(
3801                                         Importer.Import(D->getPropertyDecl()));
3802   if (!Property)
3803     return nullptr;
3804 
3805   DeclContext *DC = Importer.ImportContext(D->getDeclContext());
3806   if (!DC)
3807     return nullptr;
3808 
3809   // Import the lexical declaration context.
3810   DeclContext *LexicalDC = DC;
3811   if (D->getDeclContext() != D->getLexicalDeclContext()) {
3812     LexicalDC = Importer.ImportContext(D->getLexicalDeclContext());
3813     if (!LexicalDC)
3814       return nullptr;
3815   }
3816 
3817   ObjCImplDecl *InImpl = dyn_cast<ObjCImplDecl>(LexicalDC);
3818   if (!InImpl)
3819     return nullptr;
3820 
3821   // Import the ivar (for an @synthesize).
3822   ObjCIvarDecl *Ivar = nullptr;
3823   if (D->getPropertyIvarDecl()) {
3824     Ivar = cast_or_null<ObjCIvarDecl>(
3825                                     Importer.Import(D->getPropertyIvarDecl()));
3826     if (!Ivar)
3827       return nullptr;
3828   }
3829 
3830   ObjCPropertyImplDecl *ToImpl
3831     = InImpl->FindPropertyImplDecl(Property->getIdentifier());
3832   if (!ToImpl) {
3833     ToImpl = ObjCPropertyImplDecl::Create(Importer.getToContext(), DC,
3834                                           Importer.Import(D->getLocStart()),
3835                                           Importer.Import(D->getLocation()),
3836                                           Property,
3837                                           D->getPropertyImplementation(),
3838                                           Ivar,
3839                                   Importer.Import(D->getPropertyIvarDeclLoc()));
3840     ToImpl->setLexicalDeclContext(LexicalDC);
3841     Importer.Imported(D, ToImpl);
3842     LexicalDC->addDeclInternal(ToImpl);
3843   } else {
3844     // Check that we have the same kind of property implementation (@synthesize
3845     // vs. @dynamic).
3846     if (D->getPropertyImplementation() != ToImpl->getPropertyImplementation()) {
3847       Importer.ToDiag(ToImpl->getLocation(),
3848                       diag::err_odr_objc_property_impl_kind_inconsistent)
3849         << Property->getDeclName()
3850         << (ToImpl->getPropertyImplementation()
3851                                               == ObjCPropertyImplDecl::Dynamic);
3852       Importer.FromDiag(D->getLocation(),
3853                         diag::note_odr_objc_property_impl_kind)
3854         << D->getPropertyDecl()->getDeclName()
3855         << (D->getPropertyImplementation() == ObjCPropertyImplDecl::Dynamic);
3856       return nullptr;
3857     }
3858 
3859     // For @synthesize, check that we have the same
3860     if (D->getPropertyImplementation() == ObjCPropertyImplDecl::Synthesize &&
3861         Ivar != ToImpl->getPropertyIvarDecl()) {
3862       Importer.ToDiag(ToImpl->getPropertyIvarDeclLoc(),
3863                       diag::err_odr_objc_synthesize_ivar_inconsistent)
3864         << Property->getDeclName()
3865         << ToImpl->getPropertyIvarDecl()->getDeclName()
3866         << Ivar->getDeclName();
3867       Importer.FromDiag(D->getPropertyIvarDeclLoc(),
3868                         diag::note_odr_objc_synthesize_ivar_here)
3869         << D->getPropertyIvarDecl()->getDeclName();
3870       return nullptr;
3871     }
3872 
3873     // Merge the existing implementation with the new implementation.
3874     Importer.Imported(D, ToImpl);
3875   }
3876 
3877   return ToImpl;
3878 }
3879 
3880 Decl *ASTNodeImporter::VisitTemplateTypeParmDecl(TemplateTypeParmDecl *D) {
3881   // For template arguments, we adopt the translation unit as our declaration
3882   // context. This context will be fixed when the actual template declaration
3883   // is created.
3884 
3885   // FIXME: Import default argument.
3886   return TemplateTypeParmDecl::Create(Importer.getToContext(),
3887                               Importer.getToContext().getTranslationUnitDecl(),
3888                                       Importer.Import(D->getLocStart()),
3889                                       Importer.Import(D->getLocation()),
3890                                       D->getDepth(),
3891                                       D->getIndex(),
3892                                       Importer.Import(D->getIdentifier()),
3893                                       D->wasDeclaredWithTypename(),
3894                                       D->isParameterPack());
3895 }
3896 
3897 Decl *
3898 ASTNodeImporter::VisitNonTypeTemplateParmDecl(NonTypeTemplateParmDecl *D) {
3899   // Import the name of this declaration.
3900   DeclarationName Name = Importer.Import(D->getDeclName());
3901   if (D->getDeclName() && !Name)
3902     return nullptr;
3903 
3904   // Import the location of this declaration.
3905   SourceLocation Loc = Importer.Import(D->getLocation());
3906 
3907   // Import the type of this declaration.
3908   QualType T = Importer.Import(D->getType());
3909   if (T.isNull())
3910     return nullptr;
3911 
3912   // Import type-source information.
3913   TypeSourceInfo *TInfo = Importer.Import(D->getTypeSourceInfo());
3914   if (D->getTypeSourceInfo() && !TInfo)
3915     return nullptr;
3916 
3917   // FIXME: Import default argument.
3918 
3919   return NonTypeTemplateParmDecl::Create(Importer.getToContext(),
3920                                Importer.getToContext().getTranslationUnitDecl(),
3921                                          Importer.Import(D->getInnerLocStart()),
3922                                          Loc, D->getDepth(), D->getPosition(),
3923                                          Name.getAsIdentifierInfo(),
3924                                          T, D->isParameterPack(), TInfo);
3925 }
3926 
3927 Decl *
3928 ASTNodeImporter::VisitTemplateTemplateParmDecl(TemplateTemplateParmDecl *D) {
3929   // Import the name of this declaration.
3930   DeclarationName Name = Importer.Import(D->getDeclName());
3931   if (D->getDeclName() && !Name)
3932     return nullptr;
3933 
3934   // Import the location of this declaration.
3935   SourceLocation Loc = Importer.Import(D->getLocation());
3936 
3937   // Import template parameters.
3938   TemplateParameterList *TemplateParams
3939     = ImportTemplateParameterList(D->getTemplateParameters());
3940   if (!TemplateParams)
3941     return nullptr;
3942 
3943   // FIXME: Import default argument.
3944 
3945   return TemplateTemplateParmDecl::Create(Importer.getToContext(),
3946                               Importer.getToContext().getTranslationUnitDecl(),
3947                                           Loc, D->getDepth(), D->getPosition(),
3948                                           D->isParameterPack(),
3949                                           Name.getAsIdentifierInfo(),
3950                                           TemplateParams);
3951 }
3952 
3953 Decl *ASTNodeImporter::VisitClassTemplateDecl(ClassTemplateDecl *D) {
3954   // If this record has a definition in the translation unit we're coming from,
3955   // but this particular declaration is not that definition, import the
3956   // definition and map to that.
3957   CXXRecordDecl *Definition
3958     = cast_or_null<CXXRecordDecl>(D->getTemplatedDecl()->getDefinition());
3959   if (Definition && Definition != D->getTemplatedDecl()) {
3960     Decl *ImportedDef
3961       = Importer.Import(Definition->getDescribedClassTemplate());
3962     if (!ImportedDef)
3963       return nullptr;
3964 
3965     return Importer.Imported(D, ImportedDef);
3966   }
3967 
3968   // Import the major distinguishing characteristics of this class template.
3969   DeclContext *DC, *LexicalDC;
3970   DeclarationName Name;
3971   SourceLocation Loc;
3972   if (ImportDeclParts(D, DC, LexicalDC, Name, Loc))
3973     return nullptr;
3974 
3975   // We may already have a template of the same name; try to find and match it.
3976   if (!DC->isFunctionOrMethod()) {
3977     SmallVector<NamedDecl *, 4> ConflictingDecls;
3978     SmallVector<NamedDecl *, 2> FoundDecls;
3979     DC->localUncachedLookup(Name, FoundDecls);
3980     for (unsigned I = 0, N = FoundDecls.size(); I != N; ++I) {
3981       if (!FoundDecls[I]->isInIdentifierNamespace(Decl::IDNS_Ordinary))
3982         continue;
3983 
3984       Decl *Found = FoundDecls[I];
3985       if (ClassTemplateDecl *FoundTemplate
3986                                         = dyn_cast<ClassTemplateDecl>(Found)) {
3987         if (IsStructuralMatch(D, FoundTemplate)) {
3988           // The class templates structurally match; call it the same template.
3989           // FIXME: We may be filling in a forward declaration here. Handle
3990           // this case!
3991           Importer.Imported(D->getTemplatedDecl(),
3992                             FoundTemplate->getTemplatedDecl());
3993           return Importer.Imported(D, FoundTemplate);
3994         }
3995       }
3996 
3997       ConflictingDecls.push_back(FoundDecls[I]);
3998     }
3999 
4000     if (!ConflictingDecls.empty()) {
4001       Name = Importer.HandleNameConflict(Name, DC, Decl::IDNS_Ordinary,
4002                                          ConflictingDecls.data(),
4003                                          ConflictingDecls.size());
4004     }
4005 
4006     if (!Name)
4007       return nullptr;
4008   }
4009 
4010   CXXRecordDecl *DTemplated = D->getTemplatedDecl();
4011 
4012   // Create the declaration that is being templated.
4013   SourceLocation StartLoc = Importer.Import(DTemplated->getLocStart());
4014   SourceLocation IdLoc = Importer.Import(DTemplated->getLocation());
4015   CXXRecordDecl *D2Templated = CXXRecordDecl::Create(Importer.getToContext(),
4016                                                      DTemplated->getTagKind(),
4017                                                      DC, StartLoc, IdLoc,
4018                                                    Name.getAsIdentifierInfo());
4019   D2Templated->setAccess(DTemplated->getAccess());
4020   D2Templated->setQualifierInfo(Importer.Import(DTemplated->getQualifierLoc()));
4021   D2Templated->setLexicalDeclContext(LexicalDC);
4022 
4023   // Create the class template declaration itself.
4024   TemplateParameterList *TemplateParams
4025     = ImportTemplateParameterList(D->getTemplateParameters());
4026   if (!TemplateParams)
4027     return nullptr;
4028 
4029   ClassTemplateDecl *D2 = ClassTemplateDecl::Create(Importer.getToContext(), DC,
4030                                                     Loc, Name, TemplateParams,
4031                                                     D2Templated,
4032                                                     /*PrevDecl=*/nullptr);
4033   D2Templated->setDescribedClassTemplate(D2);
4034 
4035   D2->setAccess(D->getAccess());
4036   D2->setLexicalDeclContext(LexicalDC);
4037   LexicalDC->addDeclInternal(D2);
4038 
4039   // Note the relationship between the class templates.
4040   Importer.Imported(D, D2);
4041   Importer.Imported(DTemplated, D2Templated);
4042 
4043   if (DTemplated->isCompleteDefinition() &&
4044       !D2Templated->isCompleteDefinition()) {
4045     // FIXME: Import definition!
4046   }
4047 
4048   return D2;
4049 }
4050 
4051 Decl *ASTNodeImporter::VisitClassTemplateSpecializationDecl(
4052                                           ClassTemplateSpecializationDecl *D) {
4053   // If this record has a definition in the translation unit we're coming from,
4054   // but this particular declaration is not that definition, import the
4055   // definition and map to that.
4056   TagDecl *Definition = D->getDefinition();
4057   if (Definition && Definition != D) {
4058     Decl *ImportedDef = Importer.Import(Definition);
4059     if (!ImportedDef)
4060       return nullptr;
4061 
4062     return Importer.Imported(D, ImportedDef);
4063   }
4064 
4065   ClassTemplateDecl *ClassTemplate
4066     = cast_or_null<ClassTemplateDecl>(Importer.Import(
4067                                                  D->getSpecializedTemplate()));
4068   if (!ClassTemplate)
4069     return nullptr;
4070 
4071   // Import the context of this declaration.
4072   DeclContext *DC = ClassTemplate->getDeclContext();
4073   if (!DC)
4074     return nullptr;
4075 
4076   DeclContext *LexicalDC = DC;
4077   if (D->getDeclContext() != D->getLexicalDeclContext()) {
4078     LexicalDC = Importer.ImportContext(D->getLexicalDeclContext());
4079     if (!LexicalDC)
4080       return nullptr;
4081   }
4082 
4083   // Import the location of this declaration.
4084   SourceLocation StartLoc = Importer.Import(D->getLocStart());
4085   SourceLocation IdLoc = Importer.Import(D->getLocation());
4086 
4087   // Import template arguments.
4088   SmallVector<TemplateArgument, 2> TemplateArgs;
4089   if (ImportTemplateArguments(D->getTemplateArgs().data(),
4090                               D->getTemplateArgs().size(),
4091                               TemplateArgs))
4092     return nullptr;
4093 
4094   // Try to find an existing specialization with these template arguments.
4095   void *InsertPos = nullptr;
4096   ClassTemplateSpecializationDecl *D2
4097     = ClassTemplate->findSpecialization(TemplateArgs, InsertPos);
4098   if (D2) {
4099     // We already have a class template specialization with these template
4100     // arguments.
4101 
4102     // FIXME: Check for specialization vs. instantiation errors.
4103 
4104     if (RecordDecl *FoundDef = D2->getDefinition()) {
4105       if (!D->isCompleteDefinition() || IsStructuralMatch(D, FoundDef)) {
4106         // The record types structurally match, or the "from" translation
4107         // unit only had a forward declaration anyway; call it the same
4108         // function.
4109         return Importer.Imported(D, FoundDef);
4110       }
4111     }
4112   } else {
4113     // Create a new specialization.
4114     D2 = ClassTemplateSpecializationDecl::Create(Importer.getToContext(),
4115                                                  D->getTagKind(), DC,
4116                                                  StartLoc, IdLoc,
4117                                                  ClassTemplate,
4118                                                  TemplateArgs.data(),
4119                                                  TemplateArgs.size(),
4120                                                  /*PrevDecl=*/nullptr);
4121     D2->setSpecializationKind(D->getSpecializationKind());
4122 
4123     // Add this specialization to the class template.
4124     ClassTemplate->AddSpecialization(D2, InsertPos);
4125 
4126     // Import the qualifier, if any.
4127     D2->setQualifierInfo(Importer.Import(D->getQualifierLoc()));
4128 
4129     // Add the specialization to this context.
4130     D2->setLexicalDeclContext(LexicalDC);
4131     LexicalDC->addDeclInternal(D2);
4132   }
4133   Importer.Imported(D, D2);
4134 
4135   if (D->isCompleteDefinition() && ImportDefinition(D, D2))
4136     return nullptr;
4137 
4138   return D2;
4139 }
4140 
4141 Decl *ASTNodeImporter::VisitVarTemplateDecl(VarTemplateDecl *D) {
4142   // If this variable has a definition in the translation unit we're coming
4143   // from,
4144   // but this particular declaration is not that definition, import the
4145   // definition and map to that.
4146   VarDecl *Definition =
4147       cast_or_null<VarDecl>(D->getTemplatedDecl()->getDefinition());
4148   if (Definition && Definition != D->getTemplatedDecl()) {
4149     Decl *ImportedDef = Importer.Import(Definition->getDescribedVarTemplate());
4150     if (!ImportedDef)
4151       return nullptr;
4152 
4153     return Importer.Imported(D, ImportedDef);
4154   }
4155 
4156   // Import the major distinguishing characteristics of this variable template.
4157   DeclContext *DC, *LexicalDC;
4158   DeclarationName Name;
4159   SourceLocation Loc;
4160   if (ImportDeclParts(D, DC, LexicalDC, Name, Loc))
4161     return nullptr;
4162 
4163   // We may already have a template of the same name; try to find and match it.
4164   assert(!DC->isFunctionOrMethod() &&
4165          "Variable templates cannot be declared at function scope");
4166   SmallVector<NamedDecl *, 4> ConflictingDecls;
4167   SmallVector<NamedDecl *, 2> FoundDecls;
4168   DC->localUncachedLookup(Name, FoundDecls);
4169   for (unsigned I = 0, N = FoundDecls.size(); I != N; ++I) {
4170     if (!FoundDecls[I]->isInIdentifierNamespace(Decl::IDNS_Ordinary))
4171       continue;
4172 
4173     Decl *Found = FoundDecls[I];
4174     if (VarTemplateDecl *FoundTemplate = dyn_cast<VarTemplateDecl>(Found)) {
4175       if (IsStructuralMatch(D, FoundTemplate)) {
4176         // The variable templates structurally match; call it the same template.
4177         Importer.Imported(D->getTemplatedDecl(),
4178                           FoundTemplate->getTemplatedDecl());
4179         return Importer.Imported(D, FoundTemplate);
4180       }
4181     }
4182 
4183     ConflictingDecls.push_back(FoundDecls[I]);
4184   }
4185 
4186   if (!ConflictingDecls.empty()) {
4187     Name = Importer.HandleNameConflict(Name, DC, Decl::IDNS_Ordinary,
4188                                        ConflictingDecls.data(),
4189                                        ConflictingDecls.size());
4190   }
4191 
4192   if (!Name)
4193     return nullptr;
4194 
4195   VarDecl *DTemplated = D->getTemplatedDecl();
4196 
4197   // Import the type.
4198   QualType T = Importer.Import(DTemplated->getType());
4199   if (T.isNull())
4200     return nullptr;
4201 
4202   // Create the declaration that is being templated.
4203   SourceLocation StartLoc = Importer.Import(DTemplated->getLocStart());
4204   SourceLocation IdLoc = Importer.Import(DTemplated->getLocation());
4205   TypeSourceInfo *TInfo = Importer.Import(DTemplated->getTypeSourceInfo());
4206   VarDecl *D2Templated = VarDecl::Create(Importer.getToContext(), DC, StartLoc,
4207                                          IdLoc, Name.getAsIdentifierInfo(), T,
4208                                          TInfo, DTemplated->getStorageClass());
4209   D2Templated->setAccess(DTemplated->getAccess());
4210   D2Templated->setQualifierInfo(Importer.Import(DTemplated->getQualifierLoc()));
4211   D2Templated->setLexicalDeclContext(LexicalDC);
4212 
4213   // Importer.Imported(DTemplated, D2Templated);
4214   // LexicalDC->addDeclInternal(D2Templated);
4215 
4216   // Merge the initializer.
4217   if (ImportDefinition(DTemplated, D2Templated))
4218     return nullptr;
4219 
4220   // Create the variable template declaration itself.
4221   TemplateParameterList *TemplateParams =
4222       ImportTemplateParameterList(D->getTemplateParameters());
4223   if (!TemplateParams)
4224     return nullptr;
4225 
4226   VarTemplateDecl *D2 = VarTemplateDecl::Create(
4227       Importer.getToContext(), DC, Loc, Name, TemplateParams, D2Templated);
4228   D2Templated->setDescribedVarTemplate(D2);
4229 
4230   D2->setAccess(D->getAccess());
4231   D2->setLexicalDeclContext(LexicalDC);
4232   LexicalDC->addDeclInternal(D2);
4233 
4234   // Note the relationship between the variable templates.
4235   Importer.Imported(D, D2);
4236   Importer.Imported(DTemplated, D2Templated);
4237 
4238   if (DTemplated->isThisDeclarationADefinition() &&
4239       !D2Templated->isThisDeclarationADefinition()) {
4240     // FIXME: Import definition!
4241   }
4242 
4243   return D2;
4244 }
4245 
4246 Decl *ASTNodeImporter::VisitVarTemplateSpecializationDecl(
4247     VarTemplateSpecializationDecl *D) {
4248   // If this record has a definition in the translation unit we're coming from,
4249   // but this particular declaration is not that definition, import the
4250   // definition and map to that.
4251   VarDecl *Definition = D->getDefinition();
4252   if (Definition && Definition != D) {
4253     Decl *ImportedDef = Importer.Import(Definition);
4254     if (!ImportedDef)
4255       return nullptr;
4256 
4257     return Importer.Imported(D, ImportedDef);
4258   }
4259 
4260   VarTemplateDecl *VarTemplate = cast_or_null<VarTemplateDecl>(
4261       Importer.Import(D->getSpecializedTemplate()));
4262   if (!VarTemplate)
4263     return nullptr;
4264 
4265   // Import the context of this declaration.
4266   DeclContext *DC = VarTemplate->getDeclContext();
4267   if (!DC)
4268     return nullptr;
4269 
4270   DeclContext *LexicalDC = DC;
4271   if (D->getDeclContext() != D->getLexicalDeclContext()) {
4272     LexicalDC = Importer.ImportContext(D->getLexicalDeclContext());
4273     if (!LexicalDC)
4274       return nullptr;
4275   }
4276 
4277   // Import the location of this declaration.
4278   SourceLocation StartLoc = Importer.Import(D->getLocStart());
4279   SourceLocation IdLoc = Importer.Import(D->getLocation());
4280 
4281   // Import template arguments.
4282   SmallVector<TemplateArgument, 2> TemplateArgs;
4283   if (ImportTemplateArguments(D->getTemplateArgs().data(),
4284                               D->getTemplateArgs().size(), TemplateArgs))
4285     return nullptr;
4286 
4287   // Try to find an existing specialization with these template arguments.
4288   void *InsertPos = nullptr;
4289   VarTemplateSpecializationDecl *D2 = VarTemplate->findSpecialization(
4290       TemplateArgs, InsertPos);
4291   if (D2) {
4292     // We already have a variable template specialization with these template
4293     // arguments.
4294 
4295     // FIXME: Check for specialization vs. instantiation errors.
4296 
4297     if (VarDecl *FoundDef = D2->getDefinition()) {
4298       if (!D->isThisDeclarationADefinition() ||
4299           IsStructuralMatch(D, FoundDef)) {
4300         // The record types structurally match, or the "from" translation
4301         // unit only had a forward declaration anyway; call it the same
4302         // variable.
4303         return Importer.Imported(D, FoundDef);
4304       }
4305     }
4306   } else {
4307 
4308     // Import the type.
4309     QualType T = Importer.Import(D->getType());
4310     if (T.isNull())
4311       return nullptr;
4312     TypeSourceInfo *TInfo = Importer.Import(D->getTypeSourceInfo());
4313 
4314     // Create a new specialization.
4315     D2 = VarTemplateSpecializationDecl::Create(
4316         Importer.getToContext(), DC, StartLoc, IdLoc, VarTemplate, T, TInfo,
4317         D->getStorageClass(), TemplateArgs.data(), TemplateArgs.size());
4318     D2->setSpecializationKind(D->getSpecializationKind());
4319     D2->setTemplateArgsInfo(D->getTemplateArgsInfo());
4320 
4321     // Add this specialization to the class template.
4322     VarTemplate->AddSpecialization(D2, InsertPos);
4323 
4324     // Import the qualifier, if any.
4325     D2->setQualifierInfo(Importer.Import(D->getQualifierLoc()));
4326 
4327     // Add the specialization to this context.
4328     D2->setLexicalDeclContext(LexicalDC);
4329     LexicalDC->addDeclInternal(D2);
4330   }
4331   Importer.Imported(D, D2);
4332 
4333   if (D->isThisDeclarationADefinition() && ImportDefinition(D, D2))
4334     return nullptr;
4335 
4336   return D2;
4337 }
4338 
4339 //----------------------------------------------------------------------------
4340 // Import Statements
4341 //----------------------------------------------------------------------------
4342 
4343 Stmt *ASTNodeImporter::VisitStmt(Stmt *S) {
4344   Importer.FromDiag(S->getLocStart(), diag::err_unsupported_ast_node)
4345     << S->getStmtClassName();
4346   return nullptr;
4347 }
4348 
4349 //----------------------------------------------------------------------------
4350 // Import Expressions
4351 //----------------------------------------------------------------------------
4352 Expr *ASTNodeImporter::VisitExpr(Expr *E) {
4353   Importer.FromDiag(E->getLocStart(), diag::err_unsupported_ast_node)
4354     << E->getStmtClassName();
4355   return nullptr;
4356 }
4357 
4358 Expr *ASTNodeImporter::VisitDeclRefExpr(DeclRefExpr *E) {
4359   ValueDecl *ToD = cast_or_null<ValueDecl>(Importer.Import(E->getDecl()));
4360   if (!ToD)
4361     return nullptr;
4362 
4363   NamedDecl *FoundD = nullptr;
4364   if (E->getDecl() != E->getFoundDecl()) {
4365     FoundD = cast_or_null<NamedDecl>(Importer.Import(E->getFoundDecl()));
4366     if (!FoundD)
4367       return nullptr;
4368   }
4369 
4370   QualType T = Importer.Import(E->getType());
4371   if (T.isNull())
4372     return nullptr;
4373 
4374   DeclRefExpr *DRE = DeclRefExpr::Create(Importer.getToContext(),
4375                                          Importer.Import(E->getQualifierLoc()),
4376                                    Importer.Import(E->getTemplateKeywordLoc()),
4377                                          ToD,
4378                                          E->refersToEnclosingLocal(),
4379                                          Importer.Import(E->getLocation()),
4380                                          T, E->getValueKind(),
4381                                          FoundD,
4382                                          /*FIXME:TemplateArgs=*/nullptr);
4383   if (E->hadMultipleCandidates())
4384     DRE->setHadMultipleCandidates(true);
4385   return DRE;
4386 }
4387 
4388 Expr *ASTNodeImporter::VisitIntegerLiteral(IntegerLiteral *E) {
4389   QualType T = Importer.Import(E->getType());
4390   if (T.isNull())
4391     return nullptr;
4392 
4393   return IntegerLiteral::Create(Importer.getToContext(),
4394                                 E->getValue(), T,
4395                                 Importer.Import(E->getLocation()));
4396 }
4397 
4398 Expr *ASTNodeImporter::VisitCharacterLiteral(CharacterLiteral *E) {
4399   QualType T = Importer.Import(E->getType());
4400   if (T.isNull())
4401     return nullptr;
4402 
4403   return new (Importer.getToContext()) CharacterLiteral(E->getValue(),
4404                                                         E->getKind(), T,
4405                                           Importer.Import(E->getLocation()));
4406 }
4407 
4408 Expr *ASTNodeImporter::VisitParenExpr(ParenExpr *E) {
4409   Expr *SubExpr = Importer.Import(E->getSubExpr());
4410   if (!SubExpr)
4411     return nullptr;
4412 
4413   return new (Importer.getToContext())
4414                                   ParenExpr(Importer.Import(E->getLParen()),
4415                                             Importer.Import(E->getRParen()),
4416                                             SubExpr);
4417 }
4418 
4419 Expr *ASTNodeImporter::VisitUnaryOperator(UnaryOperator *E) {
4420   QualType T = Importer.Import(E->getType());
4421   if (T.isNull())
4422     return nullptr;
4423 
4424   Expr *SubExpr = Importer.Import(E->getSubExpr());
4425   if (!SubExpr)
4426     return nullptr;
4427 
4428   return new (Importer.getToContext()) UnaryOperator(SubExpr, E->getOpcode(),
4429                                                      T, E->getValueKind(),
4430                                                      E->getObjectKind(),
4431                                          Importer.Import(E->getOperatorLoc()));
4432 }
4433 
4434 Expr *ASTNodeImporter::VisitUnaryExprOrTypeTraitExpr(
4435                                             UnaryExprOrTypeTraitExpr *E) {
4436   QualType ResultType = Importer.Import(E->getType());
4437 
4438   if (E->isArgumentType()) {
4439     TypeSourceInfo *TInfo = Importer.Import(E->getArgumentTypeInfo());
4440     if (!TInfo)
4441       return nullptr;
4442 
4443     return new (Importer.getToContext()) UnaryExprOrTypeTraitExpr(E->getKind(),
4444                                            TInfo, ResultType,
4445                                            Importer.Import(E->getOperatorLoc()),
4446                                            Importer.Import(E->getRParenLoc()));
4447   }
4448 
4449   Expr *SubExpr = Importer.Import(E->getArgumentExpr());
4450   if (!SubExpr)
4451     return nullptr;
4452 
4453   return new (Importer.getToContext()) UnaryExprOrTypeTraitExpr(E->getKind(),
4454                                           SubExpr, ResultType,
4455                                           Importer.Import(E->getOperatorLoc()),
4456                                           Importer.Import(E->getRParenLoc()));
4457 }
4458 
4459 Expr *ASTNodeImporter::VisitBinaryOperator(BinaryOperator *E) {
4460   QualType T = Importer.Import(E->getType());
4461   if (T.isNull())
4462     return nullptr;
4463 
4464   Expr *LHS = Importer.Import(E->getLHS());
4465   if (!LHS)
4466     return nullptr;
4467 
4468   Expr *RHS = Importer.Import(E->getRHS());
4469   if (!RHS)
4470     return nullptr;
4471 
4472   return new (Importer.getToContext()) BinaryOperator(LHS, RHS, E->getOpcode(),
4473                                                       T, E->getValueKind(),
4474                                                       E->getObjectKind(),
4475                                            Importer.Import(E->getOperatorLoc()),
4476                                                       E->isFPContractable());
4477 }
4478 
4479 Expr *ASTNodeImporter::VisitCompoundAssignOperator(CompoundAssignOperator *E) {
4480   QualType T = Importer.Import(E->getType());
4481   if (T.isNull())
4482     return nullptr;
4483 
4484   QualType CompLHSType = Importer.Import(E->getComputationLHSType());
4485   if (CompLHSType.isNull())
4486     return nullptr;
4487 
4488   QualType CompResultType = Importer.Import(E->getComputationResultType());
4489   if (CompResultType.isNull())
4490     return nullptr;
4491 
4492   Expr *LHS = Importer.Import(E->getLHS());
4493   if (!LHS)
4494     return nullptr;
4495 
4496   Expr *RHS = Importer.Import(E->getRHS());
4497   if (!RHS)
4498     return nullptr;
4499 
4500   return new (Importer.getToContext())
4501                         CompoundAssignOperator(LHS, RHS, E->getOpcode(),
4502                                                T, E->getValueKind(),
4503                                                E->getObjectKind(),
4504                                                CompLHSType, CompResultType,
4505                                            Importer.Import(E->getOperatorLoc()),
4506                                                E->isFPContractable());
4507 }
4508 
4509 static bool ImportCastPath(CastExpr *E, CXXCastPath &Path) {
4510   if (E->path_empty()) return false;
4511 
4512   // TODO: import cast paths
4513   return true;
4514 }
4515 
4516 Expr *ASTNodeImporter::VisitImplicitCastExpr(ImplicitCastExpr *E) {
4517   QualType T = Importer.Import(E->getType());
4518   if (T.isNull())
4519     return nullptr;
4520 
4521   Expr *SubExpr = Importer.Import(E->getSubExpr());
4522   if (!SubExpr)
4523     return nullptr;
4524 
4525   CXXCastPath BasePath;
4526   if (ImportCastPath(E, BasePath))
4527     return nullptr;
4528 
4529   return ImplicitCastExpr::Create(Importer.getToContext(), T, E->getCastKind(),
4530                                   SubExpr, &BasePath, E->getValueKind());
4531 }
4532 
4533 Expr *ASTNodeImporter::VisitCStyleCastExpr(CStyleCastExpr *E) {
4534   QualType T = Importer.Import(E->getType());
4535   if (T.isNull())
4536     return nullptr;
4537 
4538   Expr *SubExpr = Importer.Import(E->getSubExpr());
4539   if (!SubExpr)
4540     return nullptr;
4541 
4542   TypeSourceInfo *TInfo = Importer.Import(E->getTypeInfoAsWritten());
4543   if (!TInfo && E->getTypeInfoAsWritten())
4544     return nullptr;
4545 
4546   CXXCastPath BasePath;
4547   if (ImportCastPath(E, BasePath))
4548     return nullptr;
4549 
4550   return CStyleCastExpr::Create(Importer.getToContext(), T,
4551                                 E->getValueKind(), E->getCastKind(),
4552                                 SubExpr, &BasePath, TInfo,
4553                                 Importer.Import(E->getLParenLoc()),
4554                                 Importer.Import(E->getRParenLoc()));
4555 }
4556 
4557 ASTImporter::ASTImporter(ASTContext &ToContext, FileManager &ToFileManager,
4558                          ASTContext &FromContext, FileManager &FromFileManager,
4559                          bool MinimalImport)
4560   : ToContext(ToContext), FromContext(FromContext),
4561     ToFileManager(ToFileManager), FromFileManager(FromFileManager),
4562     Minimal(MinimalImport), LastDiagFromFrom(false)
4563 {
4564   ImportedDecls[FromContext.getTranslationUnitDecl()]
4565     = ToContext.getTranslationUnitDecl();
4566 }
4567 
4568 ASTImporter::~ASTImporter() { }
4569 
4570 QualType ASTImporter::Import(QualType FromT) {
4571   if (FromT.isNull())
4572     return QualType();
4573 
4574   const Type *fromTy = FromT.getTypePtr();
4575 
4576   // Check whether we've already imported this type.
4577   llvm::DenseMap<const Type *, const Type *>::iterator Pos
4578     = ImportedTypes.find(fromTy);
4579   if (Pos != ImportedTypes.end())
4580     return ToContext.getQualifiedType(Pos->second, FromT.getLocalQualifiers());
4581 
4582   // Import the type
4583   ASTNodeImporter Importer(*this);
4584   QualType ToT = Importer.Visit(fromTy);
4585   if (ToT.isNull())
4586     return ToT;
4587 
4588   // Record the imported type.
4589   ImportedTypes[fromTy] = ToT.getTypePtr();
4590 
4591   return ToContext.getQualifiedType(ToT, FromT.getLocalQualifiers());
4592 }
4593 
4594 TypeSourceInfo *ASTImporter::Import(TypeSourceInfo *FromTSI) {
4595   if (!FromTSI)
4596     return FromTSI;
4597 
4598   // FIXME: For now we just create a "trivial" type source info based
4599   // on the type and a single location. Implement a real version of this.
4600   QualType T = Import(FromTSI->getType());
4601   if (T.isNull())
4602     return nullptr;
4603 
4604   return ToContext.getTrivialTypeSourceInfo(T,
4605                         FromTSI->getTypeLoc().getLocStart());
4606 }
4607 
4608 Decl *ASTImporter::Import(Decl *FromD) {
4609   if (!FromD)
4610     return nullptr;
4611 
4612   ASTNodeImporter Importer(*this);
4613 
4614   // Check whether we've already imported this declaration.
4615   llvm::DenseMap<Decl *, Decl *>::iterator Pos = ImportedDecls.find(FromD);
4616   if (Pos != ImportedDecls.end()) {
4617     Decl *ToD = Pos->second;
4618     Importer.ImportDefinitionIfNeeded(FromD, ToD);
4619     return ToD;
4620   }
4621 
4622   // Import the type
4623   Decl *ToD = Importer.Visit(FromD);
4624   if (!ToD)
4625     return nullptr;
4626 
4627   // Record the imported declaration.
4628   ImportedDecls[FromD] = ToD;
4629 
4630   if (TagDecl *FromTag = dyn_cast<TagDecl>(FromD)) {
4631     // Keep track of anonymous tags that have an associated typedef.
4632     if (FromTag->getTypedefNameForAnonDecl())
4633       AnonTagsWithPendingTypedefs.push_back(FromTag);
4634   } else if (TypedefNameDecl *FromTypedef = dyn_cast<TypedefNameDecl>(FromD)) {
4635     // When we've finished transforming a typedef, see whether it was the
4636     // typedef for an anonymous tag.
4637     for (SmallVectorImpl<TagDecl *>::iterator
4638                FromTag = AnonTagsWithPendingTypedefs.begin(),
4639             FromTagEnd = AnonTagsWithPendingTypedefs.end();
4640          FromTag != FromTagEnd; ++FromTag) {
4641       if ((*FromTag)->getTypedefNameForAnonDecl() == FromTypedef) {
4642         if (TagDecl *ToTag = cast_or_null<TagDecl>(Import(*FromTag))) {
4643           // We found the typedef for an anonymous tag; link them.
4644           ToTag->setTypedefNameForAnonDecl(cast<TypedefNameDecl>(ToD));
4645           AnonTagsWithPendingTypedefs.erase(FromTag);
4646           break;
4647         }
4648       }
4649     }
4650   }
4651 
4652   return ToD;
4653 }
4654 
4655 DeclContext *ASTImporter::ImportContext(DeclContext *FromDC) {
4656   if (!FromDC)
4657     return FromDC;
4658 
4659   DeclContext *ToDC = cast_or_null<DeclContext>(Import(cast<Decl>(FromDC)));
4660   if (!ToDC)
4661     return nullptr;
4662 
4663   // When we're using a record/enum/Objective-C class/protocol as a context, we
4664   // need it to have a definition.
4665   if (RecordDecl *ToRecord = dyn_cast<RecordDecl>(ToDC)) {
4666     RecordDecl *FromRecord = cast<RecordDecl>(FromDC);
4667     if (ToRecord->isCompleteDefinition()) {
4668       // Do nothing.
4669     } else if (FromRecord->isCompleteDefinition()) {
4670       ASTNodeImporter(*this).ImportDefinition(FromRecord, ToRecord,
4671                                               ASTNodeImporter::IDK_Basic);
4672     } else {
4673       CompleteDecl(ToRecord);
4674     }
4675   } else if (EnumDecl *ToEnum = dyn_cast<EnumDecl>(ToDC)) {
4676     EnumDecl *FromEnum = cast<EnumDecl>(FromDC);
4677     if (ToEnum->isCompleteDefinition()) {
4678       // Do nothing.
4679     } else if (FromEnum->isCompleteDefinition()) {
4680       ASTNodeImporter(*this).ImportDefinition(FromEnum, ToEnum,
4681                                               ASTNodeImporter::IDK_Basic);
4682     } else {
4683       CompleteDecl(ToEnum);
4684     }
4685   } else if (ObjCInterfaceDecl *ToClass = dyn_cast<ObjCInterfaceDecl>(ToDC)) {
4686     ObjCInterfaceDecl *FromClass = cast<ObjCInterfaceDecl>(FromDC);
4687     if (ToClass->getDefinition()) {
4688       // Do nothing.
4689     } else if (ObjCInterfaceDecl *FromDef = FromClass->getDefinition()) {
4690       ASTNodeImporter(*this).ImportDefinition(FromDef, ToClass,
4691                                               ASTNodeImporter::IDK_Basic);
4692     } else {
4693       CompleteDecl(ToClass);
4694     }
4695   } else if (ObjCProtocolDecl *ToProto = dyn_cast<ObjCProtocolDecl>(ToDC)) {
4696     ObjCProtocolDecl *FromProto = cast<ObjCProtocolDecl>(FromDC);
4697     if (ToProto->getDefinition()) {
4698       // Do nothing.
4699     } else if (ObjCProtocolDecl *FromDef = FromProto->getDefinition()) {
4700       ASTNodeImporter(*this).ImportDefinition(FromDef, ToProto,
4701                                               ASTNodeImporter::IDK_Basic);
4702     } else {
4703       CompleteDecl(ToProto);
4704     }
4705   }
4706 
4707   return ToDC;
4708 }
4709 
4710 Expr *ASTImporter::Import(Expr *FromE) {
4711   if (!FromE)
4712     return nullptr;
4713 
4714   return cast_or_null<Expr>(Import(cast<Stmt>(FromE)));
4715 }
4716 
4717 Stmt *ASTImporter::Import(Stmt *FromS) {
4718   if (!FromS)
4719     return nullptr;
4720 
4721   // Check whether we've already imported this declaration.
4722   llvm::DenseMap<Stmt *, Stmt *>::iterator Pos = ImportedStmts.find(FromS);
4723   if (Pos != ImportedStmts.end())
4724     return Pos->second;
4725 
4726   // Import the type
4727   ASTNodeImporter Importer(*this);
4728   Stmt *ToS = Importer.Visit(FromS);
4729   if (!ToS)
4730     return nullptr;
4731 
4732   // Record the imported declaration.
4733   ImportedStmts[FromS] = ToS;
4734   return ToS;
4735 }
4736 
4737 NestedNameSpecifier *ASTImporter::Import(NestedNameSpecifier *FromNNS) {
4738   if (!FromNNS)
4739     return nullptr;
4740 
4741   NestedNameSpecifier *prefix = Import(FromNNS->getPrefix());
4742 
4743   switch (FromNNS->getKind()) {
4744   case NestedNameSpecifier::Identifier:
4745     if (IdentifierInfo *II = Import(FromNNS->getAsIdentifier())) {
4746       return NestedNameSpecifier::Create(ToContext, prefix, II);
4747     }
4748     return nullptr;
4749 
4750   case NestedNameSpecifier::Namespace:
4751     if (NamespaceDecl *NS =
4752           cast<NamespaceDecl>(Import(FromNNS->getAsNamespace()))) {
4753       return NestedNameSpecifier::Create(ToContext, prefix, NS);
4754     }
4755     return nullptr;
4756 
4757   case NestedNameSpecifier::NamespaceAlias:
4758     if (NamespaceAliasDecl *NSAD =
4759           cast<NamespaceAliasDecl>(Import(FromNNS->getAsNamespaceAlias()))) {
4760       return NestedNameSpecifier::Create(ToContext, prefix, NSAD);
4761     }
4762     return nullptr;
4763 
4764   case NestedNameSpecifier::Global:
4765     return NestedNameSpecifier::GlobalSpecifier(ToContext);
4766 
4767   case NestedNameSpecifier::Super:
4768     if (CXXRecordDecl *RD =
4769             cast<CXXRecordDecl>(Import(FromNNS->getAsRecordDecl()))) {
4770       return NestedNameSpecifier::SuperSpecifier(ToContext, RD);
4771     }
4772     return nullptr;
4773 
4774   case NestedNameSpecifier::TypeSpec:
4775   case NestedNameSpecifier::TypeSpecWithTemplate: {
4776       QualType T = Import(QualType(FromNNS->getAsType(), 0u));
4777       if (!T.isNull()) {
4778         bool bTemplate = FromNNS->getKind() ==
4779                          NestedNameSpecifier::TypeSpecWithTemplate;
4780         return NestedNameSpecifier::Create(ToContext, prefix,
4781                                            bTemplate, T.getTypePtr());
4782       }
4783     }
4784       return nullptr;
4785   }
4786 
4787   llvm_unreachable("Invalid nested name specifier kind");
4788 }
4789 
4790 NestedNameSpecifierLoc ASTImporter::Import(NestedNameSpecifierLoc FromNNS) {
4791   // FIXME: Implement!
4792   return NestedNameSpecifierLoc();
4793 }
4794 
4795 TemplateName ASTImporter::Import(TemplateName From) {
4796   switch (From.getKind()) {
4797   case TemplateName::Template:
4798     if (TemplateDecl *ToTemplate
4799                 = cast_or_null<TemplateDecl>(Import(From.getAsTemplateDecl())))
4800       return TemplateName(ToTemplate);
4801 
4802     return TemplateName();
4803 
4804   case TemplateName::OverloadedTemplate: {
4805     OverloadedTemplateStorage *FromStorage = From.getAsOverloadedTemplate();
4806     UnresolvedSet<2> ToTemplates;
4807     for (OverloadedTemplateStorage::iterator I = FromStorage->begin(),
4808                                              E = FromStorage->end();
4809          I != E; ++I) {
4810       if (NamedDecl *To = cast_or_null<NamedDecl>(Import(*I)))
4811         ToTemplates.addDecl(To);
4812       else
4813         return TemplateName();
4814     }
4815     return ToContext.getOverloadedTemplateName(ToTemplates.begin(),
4816                                                ToTemplates.end());
4817   }
4818 
4819   case TemplateName::QualifiedTemplate: {
4820     QualifiedTemplateName *QTN = From.getAsQualifiedTemplateName();
4821     NestedNameSpecifier *Qualifier = Import(QTN->getQualifier());
4822     if (!Qualifier)
4823       return TemplateName();
4824 
4825     if (TemplateDecl *ToTemplate
4826         = cast_or_null<TemplateDecl>(Import(From.getAsTemplateDecl())))
4827       return ToContext.getQualifiedTemplateName(Qualifier,
4828                                                 QTN->hasTemplateKeyword(),
4829                                                 ToTemplate);
4830 
4831     return TemplateName();
4832   }
4833 
4834   case TemplateName::DependentTemplate: {
4835     DependentTemplateName *DTN = From.getAsDependentTemplateName();
4836     NestedNameSpecifier *Qualifier = Import(DTN->getQualifier());
4837     if (!Qualifier)
4838       return TemplateName();
4839 
4840     if (DTN->isIdentifier()) {
4841       return ToContext.getDependentTemplateName(Qualifier,
4842                                                 Import(DTN->getIdentifier()));
4843     }
4844 
4845     return ToContext.getDependentTemplateName(Qualifier, DTN->getOperator());
4846   }
4847 
4848   case TemplateName::SubstTemplateTemplateParm: {
4849     SubstTemplateTemplateParmStorage *subst
4850       = From.getAsSubstTemplateTemplateParm();
4851     TemplateTemplateParmDecl *param
4852       = cast_or_null<TemplateTemplateParmDecl>(Import(subst->getParameter()));
4853     if (!param)
4854       return TemplateName();
4855 
4856     TemplateName replacement = Import(subst->getReplacement());
4857     if (replacement.isNull()) return TemplateName();
4858 
4859     return ToContext.getSubstTemplateTemplateParm(param, replacement);
4860   }
4861 
4862   case TemplateName::SubstTemplateTemplateParmPack: {
4863     SubstTemplateTemplateParmPackStorage *SubstPack
4864       = From.getAsSubstTemplateTemplateParmPack();
4865     TemplateTemplateParmDecl *Param
4866       = cast_or_null<TemplateTemplateParmDecl>(
4867                                         Import(SubstPack->getParameterPack()));
4868     if (!Param)
4869       return TemplateName();
4870 
4871     ASTNodeImporter Importer(*this);
4872     TemplateArgument ArgPack
4873       = Importer.ImportTemplateArgument(SubstPack->getArgumentPack());
4874     if (ArgPack.isNull())
4875       return TemplateName();
4876 
4877     return ToContext.getSubstTemplateTemplateParmPack(Param, ArgPack);
4878   }
4879   }
4880 
4881   llvm_unreachable("Invalid template name kind");
4882 }
4883 
4884 SourceLocation ASTImporter::Import(SourceLocation FromLoc) {
4885   if (FromLoc.isInvalid())
4886     return SourceLocation();
4887 
4888   SourceManager &FromSM = FromContext.getSourceManager();
4889 
4890   // For now, map everything down to its spelling location, so that we
4891   // don't have to import macro expansions.
4892   // FIXME: Import macro expansions!
4893   FromLoc = FromSM.getSpellingLoc(FromLoc);
4894   std::pair<FileID, unsigned> Decomposed = FromSM.getDecomposedLoc(FromLoc);
4895   SourceManager &ToSM = ToContext.getSourceManager();
4896   return ToSM.getLocForStartOfFile(Import(Decomposed.first))
4897              .getLocWithOffset(Decomposed.second);
4898 }
4899 
4900 SourceRange ASTImporter::Import(SourceRange FromRange) {
4901   return SourceRange(Import(FromRange.getBegin()), Import(FromRange.getEnd()));
4902 }
4903 
4904 FileID ASTImporter::Import(FileID FromID) {
4905   llvm::DenseMap<FileID, FileID>::iterator Pos
4906     = ImportedFileIDs.find(FromID);
4907   if (Pos != ImportedFileIDs.end())
4908     return Pos->second;
4909 
4910   SourceManager &FromSM = FromContext.getSourceManager();
4911   SourceManager &ToSM = ToContext.getSourceManager();
4912   const SrcMgr::SLocEntry &FromSLoc = FromSM.getSLocEntry(FromID);
4913   assert(FromSLoc.isFile() && "Cannot handle macro expansions yet");
4914 
4915   // Include location of this file.
4916   SourceLocation ToIncludeLoc = Import(FromSLoc.getFile().getIncludeLoc());
4917 
4918   // Map the FileID for to the "to" source manager.
4919   FileID ToID;
4920   const SrcMgr::ContentCache *Cache = FromSLoc.getFile().getContentCache();
4921   if (Cache->OrigEntry) {
4922     // FIXME: We probably want to use getVirtualFile(), so we don't hit the
4923     // disk again
4924     // FIXME: We definitely want to re-use the existing MemoryBuffer, rather
4925     // than mmap the files several times.
4926     const FileEntry *Entry = ToFileManager.getFile(Cache->OrigEntry->getName());
4927     ToID = ToSM.createFileID(Entry, ToIncludeLoc,
4928                              FromSLoc.getFile().getFileCharacteristic());
4929   } else {
4930     // FIXME: We want to re-use the existing MemoryBuffer!
4931     const llvm::MemoryBuffer *
4932         FromBuf = Cache->getBuffer(FromContext.getDiagnostics(), FromSM);
4933     std::unique_ptr<llvm::MemoryBuffer> ToBuf
4934       = llvm::MemoryBuffer::getMemBufferCopy(FromBuf->getBuffer(),
4935                                              FromBuf->getBufferIdentifier());
4936     ToID = ToSM.createFileID(std::move(ToBuf),
4937                              FromSLoc.getFile().getFileCharacteristic());
4938   }
4939 
4940 
4941   ImportedFileIDs[FromID] = ToID;
4942   return ToID;
4943 }
4944 
4945 void ASTImporter::ImportDefinition(Decl *From) {
4946   Decl *To = Import(From);
4947   if (!To)
4948     return;
4949 
4950   if (DeclContext *FromDC = cast<DeclContext>(From)) {
4951     ASTNodeImporter Importer(*this);
4952 
4953     if (RecordDecl *ToRecord = dyn_cast<RecordDecl>(To)) {
4954       if (!ToRecord->getDefinition()) {
4955         Importer.ImportDefinition(cast<RecordDecl>(FromDC), ToRecord,
4956                                   ASTNodeImporter::IDK_Everything);
4957         return;
4958       }
4959     }
4960 
4961     if (EnumDecl *ToEnum = dyn_cast<EnumDecl>(To)) {
4962       if (!ToEnum->getDefinition()) {
4963         Importer.ImportDefinition(cast<EnumDecl>(FromDC), ToEnum,
4964                                   ASTNodeImporter::IDK_Everything);
4965         return;
4966       }
4967     }
4968 
4969     if (ObjCInterfaceDecl *ToIFace = dyn_cast<ObjCInterfaceDecl>(To)) {
4970       if (!ToIFace->getDefinition()) {
4971         Importer.ImportDefinition(cast<ObjCInterfaceDecl>(FromDC), ToIFace,
4972                                   ASTNodeImporter::IDK_Everything);
4973         return;
4974       }
4975     }
4976 
4977     if (ObjCProtocolDecl *ToProto = dyn_cast<ObjCProtocolDecl>(To)) {
4978       if (!ToProto->getDefinition()) {
4979         Importer.ImportDefinition(cast<ObjCProtocolDecl>(FromDC), ToProto,
4980                                   ASTNodeImporter::IDK_Everything);
4981         return;
4982       }
4983     }
4984 
4985     Importer.ImportDeclContext(FromDC, true);
4986   }
4987 }
4988 
4989 DeclarationName ASTImporter::Import(DeclarationName FromName) {
4990   if (!FromName)
4991     return DeclarationName();
4992 
4993   switch (FromName.getNameKind()) {
4994   case DeclarationName::Identifier:
4995     return Import(FromName.getAsIdentifierInfo());
4996 
4997   case DeclarationName::ObjCZeroArgSelector:
4998   case DeclarationName::ObjCOneArgSelector:
4999   case DeclarationName::ObjCMultiArgSelector:
5000     return Import(FromName.getObjCSelector());
5001 
5002   case DeclarationName::CXXConstructorName: {
5003     QualType T = Import(FromName.getCXXNameType());
5004     if (T.isNull())
5005       return DeclarationName();
5006 
5007     return ToContext.DeclarationNames.getCXXConstructorName(
5008                                                ToContext.getCanonicalType(T));
5009   }
5010 
5011   case DeclarationName::CXXDestructorName: {
5012     QualType T = Import(FromName.getCXXNameType());
5013     if (T.isNull())
5014       return DeclarationName();
5015 
5016     return ToContext.DeclarationNames.getCXXDestructorName(
5017                                                ToContext.getCanonicalType(T));
5018   }
5019 
5020   case DeclarationName::CXXConversionFunctionName: {
5021     QualType T = Import(FromName.getCXXNameType());
5022     if (T.isNull())
5023       return DeclarationName();
5024 
5025     return ToContext.DeclarationNames.getCXXConversionFunctionName(
5026                                                ToContext.getCanonicalType(T));
5027   }
5028 
5029   case DeclarationName::CXXOperatorName:
5030     return ToContext.DeclarationNames.getCXXOperatorName(
5031                                           FromName.getCXXOverloadedOperator());
5032 
5033   case DeclarationName::CXXLiteralOperatorName:
5034     return ToContext.DeclarationNames.getCXXLiteralOperatorName(
5035                                    Import(FromName.getCXXLiteralIdentifier()));
5036 
5037   case DeclarationName::CXXUsingDirective:
5038     // FIXME: STATICS!
5039     return DeclarationName::getUsingDirectiveName();
5040   }
5041 
5042   llvm_unreachable("Invalid DeclarationName Kind!");
5043 }
5044 
5045 IdentifierInfo *ASTImporter::Import(const IdentifierInfo *FromId) {
5046   if (!FromId)
5047     return nullptr;
5048 
5049   return &ToContext.Idents.get(FromId->getName());
5050 }
5051 
5052 Selector ASTImporter::Import(Selector FromSel) {
5053   if (FromSel.isNull())
5054     return Selector();
5055 
5056   SmallVector<IdentifierInfo *, 4> Idents;
5057   Idents.push_back(Import(FromSel.getIdentifierInfoForSlot(0)));
5058   for (unsigned I = 1, N = FromSel.getNumArgs(); I < N; ++I)
5059     Idents.push_back(Import(FromSel.getIdentifierInfoForSlot(I)));
5060   return ToContext.Selectors.getSelector(FromSel.getNumArgs(), Idents.data());
5061 }
5062 
5063 DeclarationName ASTImporter::HandleNameConflict(DeclarationName Name,
5064                                                 DeclContext *DC,
5065                                                 unsigned IDNS,
5066                                                 NamedDecl **Decls,
5067                                                 unsigned NumDecls) {
5068   return Name;
5069 }
5070 
5071 DiagnosticBuilder ASTImporter::ToDiag(SourceLocation Loc, unsigned DiagID) {
5072   if (LastDiagFromFrom)
5073     ToContext.getDiagnostics().notePriorDiagnosticFrom(
5074       FromContext.getDiagnostics());
5075   LastDiagFromFrom = false;
5076   return ToContext.getDiagnostics().Report(Loc, DiagID);
5077 }
5078 
5079 DiagnosticBuilder ASTImporter::FromDiag(SourceLocation Loc, unsigned DiagID) {
5080   if (!LastDiagFromFrom)
5081     FromContext.getDiagnostics().notePriorDiagnosticFrom(
5082       ToContext.getDiagnostics());
5083   LastDiagFromFrom = true;
5084   return FromContext.getDiagnostics().Report(Loc, DiagID);
5085 }
5086 
5087 void ASTImporter::CompleteDecl (Decl *D) {
5088   if (ObjCInterfaceDecl *ID = dyn_cast<ObjCInterfaceDecl>(D)) {
5089     if (!ID->getDefinition())
5090       ID->startDefinition();
5091   }
5092   else if (ObjCProtocolDecl *PD = dyn_cast<ObjCProtocolDecl>(D)) {
5093     if (!PD->getDefinition())
5094       PD->startDefinition();
5095   }
5096   else if (TagDecl *TD = dyn_cast<TagDecl>(D)) {
5097     if (!TD->getDefinition() && !TD->isBeingDefined()) {
5098       TD->startDefinition();
5099       TD->setCompleteDefinition(true);
5100     }
5101   }
5102   else {
5103     assert (0 && "CompleteDecl called on a Decl that can't be completed");
5104   }
5105 }
5106 
5107 Decl *ASTImporter::Imported(Decl *From, Decl *To) {
5108   ImportedDecls[From] = To;
5109   return To;
5110 }
5111 
5112 bool ASTImporter::IsStructurallyEquivalent(QualType From, QualType To,
5113                                            bool Complain) {
5114   llvm::DenseMap<const Type *, const Type *>::iterator Pos
5115    = ImportedTypes.find(From.getTypePtr());
5116   if (Pos != ImportedTypes.end() && ToContext.hasSameType(Import(From), To))
5117     return true;
5118 
5119   StructuralEquivalenceContext Ctx(FromContext, ToContext, NonEquivalentDecls,
5120                                    false, Complain);
5121   return Ctx.IsStructurallyEquivalent(From, To);
5122 }
5123