granicus.if.org Git - clang/blob - lib/AST/ASTImporter.cpp

   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     QualType VisitAttributedType(const AttributedType *T);
  71     // FIXME: TemplateTypeParmType
  72     // FIXME: SubstTemplateTypeParmType
  73     QualType VisitTemplateSpecializationType(const TemplateSpecializationType *T);
  74     QualType VisitElaboratedType(const ElaboratedType *T);
  75     // FIXME: DependentNameType
  76     // FIXME: DependentTemplateSpecializationType
  77     QualType VisitObjCInterfaceType(const ObjCInterfaceType *T);
  78     QualType VisitObjCObjectType(const ObjCObjectType *T);
  79     QualType VisitObjCObjectPointerType(const ObjCObjectPointerType *T);
  80
  81     // Importing declarations
  82     bool ImportDeclParts(NamedDecl *D, DeclContext *&DC,
  83                          DeclContext *&LexicalDC, DeclarationName &Name,
  84                          NamedDecl *&ToD, SourceLocation &Loc);
  85     void ImportDefinitionIfNeeded(Decl *FromD, Decl *ToD = nullptr);
  86     void ImportDeclarationNameLoc(const DeclarationNameInfo &From,
  87                                   DeclarationNameInfo& To);
  88     void ImportDeclContext(DeclContext *FromDC, bool ForceImport = false);
  89
  90     /// \brief What we should import from the definition.
  91     enum ImportDefinitionKind {
  92       /// \brief Import the default subset of the definition, which might be
  93       /// nothing (if minimal import is set) or might be everything (if minimal
  94       /// import is not set).
  95       IDK_Default,
  96       /// \brief Import everything.
  97       IDK_Everything,
  98       /// \brief Import only the bare bones needed to establish a valid
  99       /// DeclContext.
 100       IDK_Basic
 101     };
 102
 103     bool shouldForceImportDeclContext(ImportDefinitionKind IDK) {
 104       return IDK == IDK_Everything ||
 105              (IDK == IDK_Default && !Importer.isMinimalImport());
 106     }
 107
 108     bool ImportDefinition(RecordDecl *From, RecordDecl *To,
 109                           ImportDefinitionKind Kind = IDK_Default);
 110     bool ImportDefinition(VarDecl *From, VarDecl *To,
 111                           ImportDefinitionKind Kind = IDK_Default);
 112     bool ImportDefinition(EnumDecl *From, EnumDecl *To,
 113                           ImportDefinitionKind Kind = IDK_Default);
 114     bool ImportDefinition(ObjCInterfaceDecl *From, ObjCInterfaceDecl *To,
 115                           ImportDefinitionKind Kind = IDK_Default);
 116     bool ImportDefinition(ObjCProtocolDecl *From, ObjCProtocolDecl *To,
 117                           ImportDefinitionKind Kind = IDK_Default);
 118     TemplateParameterList *ImportTemplateParameterList(
 119                                                  TemplateParameterList *Params);
 120     TemplateArgument ImportTemplateArgument(const TemplateArgument &From);
 121     bool ImportTemplateArguments(const TemplateArgument *FromArgs,
 122                                  unsigned NumFromArgs,
 123                                SmallVectorImpl<TemplateArgument> &ToArgs);
 124     bool IsStructuralMatch(RecordDecl *FromRecord, RecordDecl *ToRecord,
 125                            bool Complain = true);
 126     bool IsStructuralMatch(VarDecl *FromVar, VarDecl *ToVar,
 127                            bool Complain = true);
 128     bool IsStructuralMatch(EnumDecl *FromEnum, EnumDecl *ToRecord);
 129     bool IsStructuralMatch(EnumConstantDecl *FromEC, EnumConstantDecl *ToEC);
 130     bool IsStructuralMatch(ClassTemplateDecl *From, ClassTemplateDecl *To);
 131     bool IsStructuralMatch(VarTemplateDecl *From, VarTemplateDecl *To);
 132     Decl *VisitDecl(Decl *D);
 133     Decl *VisitTranslationUnitDecl(TranslationUnitDecl *D);
 134     Decl *VisitNamespaceDecl(NamespaceDecl *D);
 135     Decl *VisitTypedefNameDecl(TypedefNameDecl *D, bool IsAlias);
 136     Decl *VisitTypedefDecl(TypedefDecl *D);
 137     Decl *VisitTypeAliasDecl(TypeAliasDecl *D);
 138     Decl *VisitEnumDecl(EnumDecl *D);
 139     Decl *VisitRecordDecl(RecordDecl *D);
 140     Decl *VisitEnumConstantDecl(EnumConstantDecl *D);
 141     Decl *VisitFunctionDecl(FunctionDecl *D);
 142     Decl *VisitCXXMethodDecl(CXXMethodDecl *D);
 143     Decl *VisitCXXConstructorDecl(CXXConstructorDecl *D);
 144     Decl *VisitCXXDestructorDecl(CXXDestructorDecl *D);
 145     Decl *VisitCXXConversionDecl(CXXConversionDecl *D);
 146     Decl *VisitFieldDecl(FieldDecl *D);
 147     Decl *VisitIndirectFieldDecl(IndirectFieldDecl *D);
 148     Decl *VisitObjCIvarDecl(ObjCIvarDecl *D);
 149     Decl *VisitVarDecl(VarDecl *D);
 150     Decl *VisitImplicitParamDecl(ImplicitParamDecl *D);
 151     Decl *VisitParmVarDecl(ParmVarDecl *D);
 152     Decl *VisitObjCMethodDecl(ObjCMethodDecl *D);
 153     Decl *VisitObjCTypeParamDecl(ObjCTypeParamDecl *D);
 154     Decl *VisitObjCCategoryDecl(ObjCCategoryDecl *D);
 155     Decl *VisitObjCProtocolDecl(ObjCProtocolDecl *D);
 156     Decl *VisitLinkageSpecDecl(LinkageSpecDecl *D);
 157
 158     ObjCTypeParamList *ImportObjCTypeParamList(ObjCTypeParamList *list);
 159     Decl *VisitObjCInterfaceDecl(ObjCInterfaceDecl *D);
 160     Decl *VisitObjCCategoryImplDecl(ObjCCategoryImplDecl *D);
 161     Decl *VisitObjCImplementationDecl(ObjCImplementationDecl *D);
 162     Decl *VisitObjCPropertyDecl(ObjCPropertyDecl *D);
 163     Decl *VisitObjCPropertyImplDecl(ObjCPropertyImplDecl *D);
 164     Decl *VisitTemplateTypeParmDecl(TemplateTypeParmDecl *D);
 165     Decl *VisitNonTypeTemplateParmDecl(NonTypeTemplateParmDecl *D);
 166     Decl *VisitTemplateTemplateParmDecl(TemplateTemplateParmDecl *D);
 167     Decl *VisitClassTemplateDecl(ClassTemplateDecl *D);
 168     Decl *VisitClassTemplateSpecializationDecl(
 169                                             ClassTemplateSpecializationDecl *D);
 170     Decl *VisitVarTemplateDecl(VarTemplateDecl *D);
 171     Decl *VisitVarTemplateSpecializationDecl(VarTemplateSpecializationDecl *D);
 172
 173     // Importing statements
 174     DeclGroupRef ImportDeclGroup(DeclGroupRef DG);
 175
 176     Stmt *VisitStmt(Stmt *S);
 177     Stmt *VisitDeclStmt(DeclStmt *S);
 178     Stmt *VisitNullStmt(NullStmt *S);
 179     Stmt *VisitCompoundStmt(CompoundStmt *S);
 180     Stmt *VisitCaseStmt(CaseStmt *S);
 181     Stmt *VisitDefaultStmt(DefaultStmt *S);
 182     Stmt *VisitLabelStmt(LabelStmt *S);
 183     Stmt *VisitAttributedStmt(AttributedStmt *S);
 184     Stmt *VisitIfStmt(IfStmt *S);
 185     Stmt *VisitSwitchStmt(SwitchStmt *S);
 186     Stmt *VisitWhileStmt(WhileStmt *S);
 187     Stmt *VisitDoStmt(DoStmt *S);
 188     Stmt *VisitForStmt(ForStmt *S);
 189     Stmt *VisitGotoStmt(GotoStmt *S);
 190     Stmt *VisitIndirectGotoStmt(IndirectGotoStmt *S);
 191     Stmt *VisitContinueStmt(ContinueStmt *S);
 192     Stmt *VisitBreakStmt(BreakStmt *S);
 193     Stmt *VisitReturnStmt(ReturnStmt *S);
 194     // FIXME: GCCAsmStmt
 195     // FIXME: MSAsmStmt
 196     // FIXME: SEHExceptStmt
 197     // FIXME: SEHFinallyStmt
 198     // FIXME: SEHTryStmt
 199     // FIXME: SEHLeaveStmt
 200     // FIXME: CapturedStmt
 201     Stmt *VisitCXXCatchStmt(CXXCatchStmt *S);
 202     Stmt *VisitCXXTryStmt(CXXTryStmt *S);
 203     Stmt *VisitCXXForRangeStmt(CXXForRangeStmt *S);
 204     // FIXME: MSDependentExistsStmt
 205     Stmt *VisitObjCForCollectionStmt(ObjCForCollectionStmt *S);
 206     Stmt *VisitObjCAtCatchStmt(ObjCAtCatchStmt *S);
 207     Stmt *VisitObjCAtFinallyStmt(ObjCAtFinallyStmt *S);
 208     Stmt *VisitObjCAtTryStmt(ObjCAtTryStmt *S);
 209     Stmt *VisitObjCAtSynchronizedStmt(ObjCAtSynchronizedStmt *S);
 210     Stmt *VisitObjCAtThrowStmt(ObjCAtThrowStmt *S);
 211     Stmt *VisitObjCAutoreleasePoolStmt(ObjCAutoreleasePoolStmt *S);
 212
 213     // Importing expressions
 214     Expr *VisitExpr(Expr *E);
 215     Expr *VisitDeclRefExpr(DeclRefExpr *E);
 216     Expr *VisitIntegerLiteral(IntegerLiteral *E);
 217     Expr *VisitCharacterLiteral(CharacterLiteral *E);
 218     Expr *VisitParenExpr(ParenExpr *E);
 219     Expr *VisitUnaryOperator(UnaryOperator *E);
 220     Expr *VisitUnaryExprOrTypeTraitExpr(UnaryExprOrTypeTraitExpr *E);
 221     Expr *VisitBinaryOperator(BinaryOperator *E);
 222     Expr *VisitCompoundAssignOperator(CompoundAssignOperator *E);
 223     Expr *VisitImplicitCastExpr(ImplicitCastExpr *E);
 224     Expr *VisitCStyleCastExpr(CStyleCastExpr *E);
 225     Expr *VisitCXXConstructExpr(CXXConstructExpr *E);
 226     Expr *VisitMemberExpr(MemberExpr *E);
 227     Expr *VisitCallExpr(CallExpr *E);
 228   };
 229 }
 230 using namespace clang;
 231
 232 //----------------------------------------------------------------------------
 233 // Structural Equivalence
 234 //----------------------------------------------------------------------------
 235
 236 namespace {
 237   struct StructuralEquivalenceContext {
 238     /// \brief AST contexts for which we are checking structural equivalence.
 239     ASTContext &C1, &C2;
 240
 241     /// \brief The set of "tentative" equivalences between two canonical
 242     /// declarations, mapping from a declaration in the first context to the
 243     /// declaration in the second context that we believe to be equivalent.
 244     llvm::DenseMap<Decl *, Decl *> TentativeEquivalences;
 245
 246     /// \brief Queue of declarations in the first context whose equivalence
 247     /// with a declaration in the second context still needs to be verified.
 248     std::deque<Decl *> DeclsToCheck;
 249
 250     /// \brief Declaration (from, to) pairs that are known not to be equivalent
 251     /// (which we have already complained about).
 252     llvm::DenseSet<std::pair<Decl *, Decl *> > &NonEquivalentDecls;
 253
 254     /// \brief Whether we're being strict about the spelling of types when
 255     /// unifying two types.
 256     bool StrictTypeSpelling;
 257
 258     /// \brief Whether to complain about failures.
 259     bool Complain;
 260
 261     /// \brief \c true if the last diagnostic came from C2.
 262     bool LastDiagFromC2;
 263
 264     StructuralEquivalenceContext(ASTContext &C1, ASTContext &C2,
 265                llvm::DenseSet<std::pair<Decl *, Decl *> > &NonEquivalentDecls,
 266                                  bool StrictTypeSpelling = false,
 267                                  bool Complain = true)
 268       : C1(C1), C2(C2), NonEquivalentDecls(NonEquivalentDecls),
 269         StrictTypeSpelling(StrictTypeSpelling), Complain(Complain),
 270         LastDiagFromC2(false) {}
 271
 272     /// \brief Determine whether the two declarations are structurally
 273     /// equivalent.
 274     bool IsStructurallyEquivalent(Decl *D1, Decl *D2);
 275
 276     /// \brief Determine whether the two types are structurally equivalent.
 277     bool IsStructurallyEquivalent(QualType T1, QualType T2);
 278
 279   private:
 280     /// \brief Finish checking all of the structural equivalences.
 281     ///
 282     /// \returns true if an error occurred, false otherwise.
 283     bool Finish();
 284
 285   public:
 286     DiagnosticBuilder Diag1(SourceLocation Loc, unsigned DiagID) {
 287       assert(Complain && "Not allowed to complain");
 288       if (LastDiagFromC2)
 289         C1.getDiagnostics().notePriorDiagnosticFrom(C2.getDiagnostics());
 290       LastDiagFromC2 = false;
 291       return C1.getDiagnostics().Report(Loc, DiagID);
 292     }
 293
 294     DiagnosticBuilder Diag2(SourceLocation Loc, unsigned DiagID) {
 295       assert(Complain && "Not allowed to complain");
 296       if (!LastDiagFromC2)
 297         C2.getDiagnostics().notePriorDiagnosticFrom(C1.getDiagnostics());
 298       LastDiagFromC2 = true;
 299       return C2.getDiagnostics().Report(Loc, DiagID);
 300     }
 301   };
 302 }
 303
 304 static bool IsStructurallyEquivalent(StructuralEquivalenceContext &Context,
 305                                      QualType T1, QualType T2);
 306 static bool IsStructurallyEquivalent(StructuralEquivalenceContext &Context,
 307                                      Decl *D1, Decl *D2);
 308
 309 /// \brief Determine structural equivalence of two expressions.
 310 static bool IsStructurallyEquivalent(StructuralEquivalenceContext &Context,
 311                                      Expr *E1, Expr *E2) {
 312   if (!E1 || !E2)
 313     return E1 == E2;
 314
 315   // FIXME: Actually perform a structural comparison!
 316   return true;
 317 }
 318
 319 /// \brief Determine whether two identifiers are equivalent.
 320 static bool IsStructurallyEquivalent(const IdentifierInfo *Name1,
 321                                      const IdentifierInfo *Name2) {
 322   if (!Name1 || !Name2)
 323     return Name1 == Name2;
 324
 325   return Name1->getName() == Name2->getName();
 326 }
 327
 328 /// \brief Determine whether two nested-name-specifiers are equivalent.
 329 static bool IsStructurallyEquivalent(StructuralEquivalenceContext &Context,
 330                                      NestedNameSpecifier *NNS1,
 331                                      NestedNameSpecifier *NNS2) {
 332   // FIXME: Implement!
 333   return true;
 334 }
 335
 336 /// \brief Determine whether two template arguments are equivalent.
 337 static bool IsStructurallyEquivalent(StructuralEquivalenceContext &Context,
 338                                      const TemplateArgument &Arg1,
 339                                      const TemplateArgument &Arg2) {
 340   if (Arg1.getKind() != Arg2.getKind())
 341     return false;
 342
 343   switch (Arg1.getKind()) {
 344   case TemplateArgument::Null:
 345     return true;
 346
 347   case TemplateArgument::Type:
 348     return Context.IsStructurallyEquivalent(Arg1.getAsType(), Arg2.getAsType());
 349
 350   case TemplateArgument::Integral:
 351     if (!Context.IsStructurallyEquivalent(Arg1.getIntegralType(),
 352                                           Arg2.getIntegralType()))
 353       return false;
 354
 355     return llvm::APSInt::isSameValue(Arg1.getAsIntegral(), Arg2.getAsIntegral());
 356
 357   case TemplateArgument::Declaration:
 358     return Context.IsStructurallyEquivalent(Arg1.getAsDecl(), Arg2.getAsDecl());
 359
 360   case TemplateArgument::NullPtr:
 361     return true; // FIXME: Is this correct?
 362
 363   case TemplateArgument::Template:
 364     return IsStructurallyEquivalent(Context,
 365                                     Arg1.getAsTemplate(),
 366                                     Arg2.getAsTemplate());
 367
 368   case TemplateArgument::TemplateExpansion:
 369     return IsStructurallyEquivalent(Context,
 370                                     Arg1.getAsTemplateOrTemplatePattern(),
 371                                     Arg2.getAsTemplateOrTemplatePattern());
 372
 373   case TemplateArgument::Expression:
 374     return IsStructurallyEquivalent(Context,
 375                                     Arg1.getAsExpr(), Arg2.getAsExpr());
 376
 377   case TemplateArgument::Pack:
 378     if (Arg1.pack_size() != Arg2.pack_size())
 379       return false;
 380
 381     for (unsigned I = 0, N = Arg1.pack_size(); I != N; ++I)
 382       if (!IsStructurallyEquivalent(Context,
 383                                     Arg1.pack_begin()[I],
 384                                     Arg2.pack_begin()[I]))
 385         return false;
 386
 387     return true;
 388   }
 389
 390   llvm_unreachable("Invalid template argument kind");
 391 }
 392
 393 /// \brief Determine structural equivalence for the common part of array
 394 /// types.
 395 static bool IsArrayStructurallyEquivalent(StructuralEquivalenceContext &Context,
 396                                           const ArrayType *Array1,
 397                                           const ArrayType *Array2) {
 398   if (!IsStructurallyEquivalent(Context,
 399                                 Array1->getElementType(),
 400                                 Array2->getElementType()))
 401     return false;
 402   if (Array1->getSizeModifier() != Array2->getSizeModifier())
 403     return false;
 404   if (Array1->getIndexTypeQualifiers() != Array2->getIndexTypeQualifiers())
 405     return false;
 406
 407   return true;
 408 }
 409
 410 /// \brief Determine structural equivalence of two types.
 411 static bool IsStructurallyEquivalent(StructuralEquivalenceContext &Context,
 412                                      QualType T1, QualType T2) {
 413   if (T1.isNull() || T2.isNull())
 414     return T1.isNull() && T2.isNull();
 415
 416   if (!Context.StrictTypeSpelling) {
 417     // We aren't being strict about token-to-token equivalence of types,
 418     // so map down to the canonical type.
 419     T1 = Context.C1.getCanonicalType(T1);
 420     T2 = Context.C2.getCanonicalType(T2);
 421   }
 422
 423   if (T1.getQualifiers() != T2.getQualifiers())
 424     return false;
 425
 426   Type::TypeClass TC = T1->getTypeClass();
 427
 428   if (T1->getTypeClass() != T2->getTypeClass()) {
 429     // Compare function types with prototypes vs. without prototypes as if
 430     // both did not have prototypes.
 431     if (T1->getTypeClass() == Type::FunctionProto &&
 432         T2->getTypeClass() == Type::FunctionNoProto)
 433       TC = Type::FunctionNoProto;
 434     else if (T1->getTypeClass() == Type::FunctionNoProto &&
 435              T2->getTypeClass() == Type::FunctionProto)
 436       TC = Type::FunctionNoProto;
 437     else
 438       return false;
 439   }
 440
 441   switch (TC) {
 442   case Type::Builtin:
 443     // FIXME: Deal with Char_S/Char_U.
 444     if (cast<BuiltinType>(T1)->getKind() != cast<BuiltinType>(T2)->getKind())
 445       return false;
 446     break;
 447
 448   case Type::Complex:
 449     if (!IsStructurallyEquivalent(Context,
 450                                   cast<ComplexType>(T1)->getElementType(),
 451                                   cast<ComplexType>(T2)->getElementType()))
 452       return false;
 453     break;
 454
 455   case Type::Adjusted:
 456   case Type::Decayed:
 457     if (!IsStructurallyEquivalent(Context,
 458                                   cast<AdjustedType>(T1)->getOriginalType(),
 459                                   cast<AdjustedType>(T2)->getOriginalType()))
 460       return false;
 461     break;
 462
 463   case Type::Pointer:
 464     if (!IsStructurallyEquivalent(Context,
 465                                   cast<PointerType>(T1)->getPointeeType(),
 466                                   cast<PointerType>(T2)->getPointeeType()))
 467       return false;
 468     break;
 469
 470   case Type::BlockPointer:
 471     if (!IsStructurallyEquivalent(Context,
 472                                   cast<BlockPointerType>(T1)->getPointeeType(),
 473                                   cast<BlockPointerType>(T2)->getPointeeType()))
 474       return false;
 475     break;
 476
 477   case Type::LValueReference:
 478   case Type::RValueReference: {
 479     const ReferenceType *Ref1 = cast<ReferenceType>(T1);
 480     const ReferenceType *Ref2 = cast<ReferenceType>(T2);
 481     if (Ref1->isSpelledAsLValue() != Ref2->isSpelledAsLValue())
 482       return false;
 483     if (Ref1->isInnerRef() != Ref2->isInnerRef())
 484       return false;
 485     if (!IsStructurallyEquivalent(Context,
 486                                   Ref1->getPointeeTypeAsWritten(),
 487                                   Ref2->getPointeeTypeAsWritten()))
 488       return false;
 489     break;
 490   }
 491
 492   case Type::MemberPointer: {
 493     const MemberPointerType *MemPtr1 = cast<MemberPointerType>(T1);
 494     const MemberPointerType *MemPtr2 = cast<MemberPointerType>(T2);
 495     if (!IsStructurallyEquivalent(Context,
 496                                   MemPtr1->getPointeeType(),
 497                                   MemPtr2->getPointeeType()))
 498       return false;
 499     if (!IsStructurallyEquivalent(Context,
 500                                   QualType(MemPtr1->getClass(), 0),
 501                                   QualType(MemPtr2->getClass(), 0)))
 502       return false;
 503     break;
 504   }
 505
 506   case Type::ConstantArray: {
 507     const ConstantArrayType *Array1 = cast<ConstantArrayType>(T1);
 508     const ConstantArrayType *Array2 = cast<ConstantArrayType>(T2);
 509     if (!llvm::APInt::isSameValue(Array1->getSize(), Array2->getSize()))
 510       return false;
 511
 512     if (!IsArrayStructurallyEquivalent(Context, Array1, Array2))
 513       return false;
 514     break;
 515   }
 516
 517   case Type::IncompleteArray:
 518     if (!IsArrayStructurallyEquivalent(Context,
 519                                        cast<ArrayType>(T1),
 520                                        cast<ArrayType>(T2)))
 521       return false;
 522     break;
 523
 524   case Type::VariableArray: {
 525     const VariableArrayType *Array1 = cast<VariableArrayType>(T1);
 526     const VariableArrayType *Array2 = cast<VariableArrayType>(T2);
 527     if (!IsStructurallyEquivalent(Context,
 528                                   Array1->getSizeExpr(), Array2->getSizeExpr()))
 529       return false;
 530
 531     if (!IsArrayStructurallyEquivalent(Context, Array1, Array2))
 532       return false;
 533
 534     break;
 535   }
 536
 537   case Type::DependentSizedArray: {
 538     const DependentSizedArrayType *Array1 = cast<DependentSizedArrayType>(T1);
 539     const DependentSizedArrayType *Array2 = cast<DependentSizedArrayType>(T2);
 540     if (!IsStructurallyEquivalent(Context,
 541                                   Array1->getSizeExpr(), Array2->getSizeExpr()))
 542       return false;
 543
 544     if (!IsArrayStructurallyEquivalent(Context, Array1, Array2))
 545       return false;
 546
 547     break;
 548   }
 549
 550   case Type::DependentSizedExtVector: {
 551     const DependentSizedExtVectorType *Vec1
 552       = cast<DependentSizedExtVectorType>(T1);
 553     const DependentSizedExtVectorType *Vec2
 554       = cast<DependentSizedExtVectorType>(T2);
 555     if (!IsStructurallyEquivalent(Context,
 556                                   Vec1->getSizeExpr(), Vec2->getSizeExpr()))
 557       return false;
 558     if (!IsStructurallyEquivalent(Context,
 559                                   Vec1->getElementType(),
 560                                   Vec2->getElementType()))
 561       return false;
 562     break;
 563   }
 564
 565   case Type::Vector:
 566   case Type::ExtVector: {
 567     const VectorType *Vec1 = cast<VectorType>(T1);
 568     const VectorType *Vec2 = cast<VectorType>(T2);
 569     if (!IsStructurallyEquivalent(Context,
 570                                   Vec1->getElementType(),
 571                                   Vec2->getElementType()))
 572       return false;
 573     if (Vec1->getNumElements() != Vec2->getNumElements())
 574       return false;
 575     if (Vec1->getVectorKind() != Vec2->getVectorKind())
 576       return false;
 577     break;
 578   }
 579
 580   case Type::FunctionProto: {
 581     const FunctionProtoType *Proto1 = cast<FunctionProtoType>(T1);
 582     const FunctionProtoType *Proto2 = cast<FunctionProtoType>(T2);
 583     if (Proto1->getNumParams() != Proto2->getNumParams())
 584       return false;
 585     for (unsigned I = 0, N = Proto1->getNumParams(); I != N; ++I) {
 586       if (!IsStructurallyEquivalent(Context, Proto1->getParamType(I),
 587                                     Proto2->getParamType(I)))
 588         return false;
 589     }
 590     if (Proto1->isVariadic() != Proto2->isVariadic())
 591       return false;
 592     if (Proto1->getExceptionSpecType() != Proto2->getExceptionSpecType())
 593       return false;
 594     if (Proto1->getExceptionSpecType() == EST_Dynamic) {
 595       if (Proto1->getNumExceptions() != Proto2->getNumExceptions())
 596         return false;
 597       for (unsigned I = 0, N = Proto1->getNumExceptions(); I != N; ++I) {
 598         if (!IsStructurallyEquivalent(Context,
 599                                       Proto1->getExceptionType(I),
 600                                       Proto2->getExceptionType(I)))
 601           return false;
 602       }
 603     } else if (Proto1->getExceptionSpecType() == EST_ComputedNoexcept) {
 604       if (!IsStructurallyEquivalent(Context,
 605                                     Proto1->getNoexceptExpr(),
 606                                     Proto2->getNoexceptExpr()))
 607         return false;
 608     }
 609     if (Proto1->getTypeQuals() != Proto2->getTypeQuals())
 610       return false;
 611
 612     // Fall through to check the bits common with FunctionNoProtoType.
 613   }
 614
 615   case Type::FunctionNoProto: {
 616     const FunctionType *Function1 = cast<FunctionType>(T1);
 617     const FunctionType *Function2 = cast<FunctionType>(T2);
 618     if (!IsStructurallyEquivalent(Context, Function1->getReturnType(),
 619                                   Function2->getReturnType()))
 620       return false;
 621       if (Function1->getExtInfo() != Function2->getExtInfo())
 622         return false;
 623     break;
 624   }
 625
 626   case Type::UnresolvedUsing:
 627     if (!IsStructurallyEquivalent(Context,
 628                                   cast<UnresolvedUsingType>(T1)->getDecl(),
 629                                   cast<UnresolvedUsingType>(T2)->getDecl()))
 630       return false;
 631
 632     break;
 633
 634   case Type::Attributed:
 635     if (!IsStructurallyEquivalent(Context,
 636                                   cast<AttributedType>(T1)->getModifiedType(),
 637                                   cast<AttributedType>(T2)->getModifiedType()))
 638       return false;
 639     if (!IsStructurallyEquivalent(Context,
 640                                 cast<AttributedType>(T1)->getEquivalentType(),
 641                                 cast<AttributedType>(T2)->getEquivalentType()))
 642       return false;
 643     break;
 644
 645   case Type::Paren:
 646     if (!IsStructurallyEquivalent(Context,
 647                                   cast<ParenType>(T1)->getInnerType(),
 648                                   cast<ParenType>(T2)->getInnerType()))
 649       return false;
 650     break;
 651
 652   case Type::Typedef:
 653     if (!IsStructurallyEquivalent(Context,
 654                                   cast<TypedefType>(T1)->getDecl(),
 655                                   cast<TypedefType>(T2)->getDecl()))
 656       return false;
 657     break;
 658
 659   case Type::TypeOfExpr:
 660     if (!IsStructurallyEquivalent(Context,
 661                                 cast<TypeOfExprType>(T1)->getUnderlyingExpr(),
 662                                 cast<TypeOfExprType>(T2)->getUnderlyingExpr()))
 663       return false;
 664     break;
 665
 666   case Type::TypeOf:
 667     if (!IsStructurallyEquivalent(Context,
 668                                   cast<TypeOfType>(T1)->getUnderlyingType(),
 669                                   cast<TypeOfType>(T2)->getUnderlyingType()))
 670       return false;
 671     break;
 672
 673   case Type::UnaryTransform:
 674     if (!IsStructurallyEquivalent(Context,
 675                              cast<UnaryTransformType>(T1)->getUnderlyingType(),
 676                              cast<UnaryTransformType>(T1)->getUnderlyingType()))
 677       return false;
 678     break;
 679
 680   case Type::Decltype:
 681     if (!IsStructurallyEquivalent(Context,
 682                                   cast<DecltypeType>(T1)->getUnderlyingExpr(),
 683                                   cast<DecltypeType>(T2)->getUnderlyingExpr()))
 684       return false;
 685     break;
 686
 687   case Type::Auto:
 688     if (!IsStructurallyEquivalent(Context,
 689                                   cast<AutoType>(T1)->getDeducedType(),
 690                                   cast<AutoType>(T2)->getDeducedType()))
 691       return false;
 692     break;
 693
 694   case Type::Record:
 695   case Type::Enum:
 696     if (!IsStructurallyEquivalent(Context,
 697                                   cast<TagType>(T1)->getDecl(),
 698                                   cast<TagType>(T2)->getDecl()))
 699       return false;
 700     break;
 701
 702   case Type::TemplateTypeParm: {
 703     const TemplateTypeParmType *Parm1 = cast<TemplateTypeParmType>(T1);
 704     const TemplateTypeParmType *Parm2 = cast<TemplateTypeParmType>(T2);
 705     if (Parm1->getDepth() != Parm2->getDepth())
 706       return false;
 707     if (Parm1->getIndex() != Parm2->getIndex())
 708       return false;
 709     if (Parm1->isParameterPack() != Parm2->isParameterPack())
 710       return false;
 711
 712     // Names of template type parameters are never significant.
 713     break;
 714   }
 715
 716   case Type::SubstTemplateTypeParm: {
 717     const SubstTemplateTypeParmType *Subst1
 718       = cast<SubstTemplateTypeParmType>(T1);
 719     const SubstTemplateTypeParmType *Subst2
 720       = cast<SubstTemplateTypeParmType>(T2);
 721     if (!IsStructurallyEquivalent(Context,
 722                                   QualType(Subst1->getReplacedParameter(), 0),
 723                                   QualType(Subst2->getReplacedParameter(), 0)))
 724       return false;
 725     if (!IsStructurallyEquivalent(Context,
 726                                   Subst1->getReplacementType(),
 727                                   Subst2->getReplacementType()))
 728       return false;
 729     break;
 730   }
 731
 732   case Type::SubstTemplateTypeParmPack: {
 733     const SubstTemplateTypeParmPackType *Subst1
 734       = cast<SubstTemplateTypeParmPackType>(T1);
 735     const SubstTemplateTypeParmPackType *Subst2
 736       = cast<SubstTemplateTypeParmPackType>(T2);
 737     if (!IsStructurallyEquivalent(Context,
 738                                   QualType(Subst1->getReplacedParameter(), 0),
 739                                   QualType(Subst2->getReplacedParameter(), 0)))
 740       return false;
 741     if (!IsStructurallyEquivalent(Context,
 742                                   Subst1->getArgumentPack(),
 743                                   Subst2->getArgumentPack()))
 744       return false;
 745     break;
 746   }
 747   case Type::TemplateSpecialization: {
 748     const TemplateSpecializationType *Spec1
 749       = cast<TemplateSpecializationType>(T1);
 750     const TemplateSpecializationType *Spec2
 751       = cast<TemplateSpecializationType>(T2);
 752     if (!IsStructurallyEquivalent(Context,
 753                                   Spec1->getTemplateName(),
 754                                   Spec2->getTemplateName()))
 755       return false;
 756     if (Spec1->getNumArgs() != Spec2->getNumArgs())
 757       return false;
 758     for (unsigned I = 0, N = Spec1->getNumArgs(); I != N; ++I) {
 759       if (!IsStructurallyEquivalent(Context,
 760                                     Spec1->getArg(I), Spec2->getArg(I)))
 761         return false;
 762     }
 763     break;
 764   }
 765
 766   case Type::Elaborated: {
 767     const ElaboratedType *Elab1 = cast<ElaboratedType>(T1);
 768     const ElaboratedType *Elab2 = cast<ElaboratedType>(T2);
 769     // CHECKME: what if a keyword is ETK_None or ETK_typename ?
 770     if (Elab1->getKeyword() != Elab2->getKeyword())
 771       return false;
 772     if (!IsStructurallyEquivalent(Context,
 773                                   Elab1->getQualifier(),
 774                                   Elab2->getQualifier()))
 775       return false;
 776     if (!IsStructurallyEquivalent(Context,
 777                                   Elab1->getNamedType(),
 778                                   Elab2->getNamedType()))
 779       return false;
 780     break;
 781   }
 782
 783   case Type::InjectedClassName: {
 784     const InjectedClassNameType *Inj1 = cast<InjectedClassNameType>(T1);
 785     const InjectedClassNameType *Inj2 = cast<InjectedClassNameType>(T2);
 786     if (!IsStructurallyEquivalent(Context,
 787                                   Inj1->getInjectedSpecializationType(),
 788                                   Inj2->getInjectedSpecializationType()))
 789       return false;
 790     break;
 791   }
 792
 793   case Type::DependentName: {
 794     const DependentNameType *Typename1 = cast<DependentNameType>(T1);
 795     const DependentNameType *Typename2 = cast<DependentNameType>(T2);
 796     if (!IsStructurallyEquivalent(Context,
 797                                   Typename1->getQualifier(),
 798                                   Typename2->getQualifier()))
 799       return false;
 800     if (!IsStructurallyEquivalent(Typename1->getIdentifier(),
 801                                   Typename2->getIdentifier()))
 802       return false;
 803
 804     break;
 805   }
 806
 807   case Type::DependentTemplateSpecialization: {
 808     const DependentTemplateSpecializationType *Spec1 =
 809       cast<DependentTemplateSpecializationType>(T1);
 810     const DependentTemplateSpecializationType *Spec2 =
 811       cast<DependentTemplateSpecializationType>(T2);
 812     if (!IsStructurallyEquivalent(Context,
 813                                   Spec1->getQualifier(),
 814                                   Spec2->getQualifier()))
 815       return false;
 816     if (!IsStructurallyEquivalent(Spec1->getIdentifier(),
 817                                   Spec2->getIdentifier()))
 818       return false;
 819     if (Spec1->getNumArgs() != Spec2->getNumArgs())
 820       return false;
 821     for (unsigned I = 0, N = Spec1->getNumArgs(); I != N; ++I) {
 822       if (!IsStructurallyEquivalent(Context,
 823                                     Spec1->getArg(I), Spec2->getArg(I)))
 824         return false;
 825     }
 826     break;
 827   }
 828
 829   case Type::PackExpansion:
 830     if (!IsStructurallyEquivalent(Context,
 831                                   cast<PackExpansionType>(T1)->getPattern(),
 832                                   cast<PackExpansionType>(T2)->getPattern()))
 833       return false;
 834     break;
 835
 836   case Type::ObjCInterface: {
 837     const ObjCInterfaceType *Iface1 = cast<ObjCInterfaceType>(T1);
 838     const ObjCInterfaceType *Iface2 = cast<ObjCInterfaceType>(T2);
 839     if (!IsStructurallyEquivalent(Context,
 840                                   Iface1->getDecl(), Iface2->getDecl()))
 841       return false;
 842     break;
 843   }
 844
 845   case Type::ObjCObject: {
 846     const ObjCObjectType *Obj1 = cast<ObjCObjectType>(T1);
 847     const ObjCObjectType *Obj2 = cast<ObjCObjectType>(T2);
 848     if (!IsStructurallyEquivalent(Context,
 849                                   Obj1->getBaseType(),
 850                                   Obj2->getBaseType()))
 851       return false;
 852     if (Obj1->getNumProtocols() != Obj2->getNumProtocols())
 853       return false;
 854     for (unsigned I = 0, N = Obj1->getNumProtocols(); I != N; ++I) {
 855       if (!IsStructurallyEquivalent(Context,
 856                                     Obj1->getProtocol(I),
 857                                     Obj2->getProtocol(I)))
 858         return false;
 859     }
 860     break;
 861   }
 862
 863   case Type::ObjCObjectPointer: {
 864     const ObjCObjectPointerType *Ptr1 = cast<ObjCObjectPointerType>(T1);
 865     const ObjCObjectPointerType *Ptr2 = cast<ObjCObjectPointerType>(T2);
 866     if (!IsStructurallyEquivalent(Context,
 867                                   Ptr1->getPointeeType(),
 868                                   Ptr2->getPointeeType()))
 869       return false;
 870     break;
 871   }
 872
 873   case Type::Atomic: {
 874     if (!IsStructurallyEquivalent(Context,
 875                                   cast<AtomicType>(T1)->getValueType(),
 876                                   cast<AtomicType>(T2)->getValueType()))
 877       return false;
 878     break;
 879   }
 880
 881   } // end switch
 882
 883   return true;
 884 }
 885
 886 /// \brief Determine structural equivalence of two fields.
 887 static bool IsStructurallyEquivalent(StructuralEquivalenceContext &Context,
 888                                      FieldDecl *Field1, FieldDecl *Field2) {
 889   RecordDecl *Owner2 = cast<RecordDecl>(Field2->getDeclContext());
 890
 891   // For anonymous structs/unions, match up the anonymous struct/union type
 892   // declarations directly, so that we don't go off searching for anonymous
 893   // types
 894   if (Field1->isAnonymousStructOrUnion() &&
 895       Field2->isAnonymousStructOrUnion()) {
 896     RecordDecl *D1 = Field1->getType()->castAs<RecordType>()->getDecl();
 897     RecordDecl *D2 = Field2->getType()->castAs<RecordType>()->getDecl();
 898     return IsStructurallyEquivalent(Context, D1, D2);
 899   }
 900
 901   // Check for equivalent field names.
 902   IdentifierInfo *Name1 = Field1->getIdentifier();
 903   IdentifierInfo *Name2 = Field2->getIdentifier();
 904   if (!::IsStructurallyEquivalent(Name1, Name2))
 905     return false;
 906
 907   if (!IsStructurallyEquivalent(Context,
 908                                 Field1->getType(), Field2->getType())) {
 909     if (Context.Complain) {
 910       Context.Diag2(Owner2->getLocation(), diag::warn_odr_tag_type_inconsistent)
 911         << Context.C2.getTypeDeclType(Owner2);
 912       Context.Diag2(Field2->getLocation(), diag::note_odr_field)
 913         << Field2->getDeclName() << Field2->getType();
 914       Context.Diag1(Field1->getLocation(), diag::note_odr_field)
 915         << Field1->getDeclName() << Field1->getType();
 916     }
 917     return false;
 918   }
 919
 920   if (Field1->isBitField() != Field2->isBitField()) {
 921     if (Context.Complain) {
 922       Context.Diag2(Owner2->getLocation(), diag::warn_odr_tag_type_inconsistent)
 923         << Context.C2.getTypeDeclType(Owner2);
 924       if (Field1->isBitField()) {
 925         Context.Diag1(Field1->getLocation(), diag::note_odr_bit_field)
 926         << Field1->getDeclName() << Field1->getType()
 927         << Field1->getBitWidthValue(Context.C1);
 928         Context.Diag2(Field2->getLocation(), diag::note_odr_not_bit_field)
 929         << Field2->getDeclName();
 930       } else {
 931         Context.Diag2(Field2->getLocation(), diag::note_odr_bit_field)
 932         << Field2->getDeclName() << Field2->getType()
 933         << Field2->getBitWidthValue(Context.C2);
 934         Context.Diag1(Field1->getLocation(), diag::note_odr_not_bit_field)
 935         << Field1->getDeclName();
 936       }
 937     }
 938     return false;
 939   }
 940
 941   if (Field1->isBitField()) {
 942     // Make sure that the bit-fields are the same length.
 943     unsigned Bits1 = Field1->getBitWidthValue(Context.C1);
 944     unsigned Bits2 = Field2->getBitWidthValue(Context.C2);
 945
 946     if (Bits1 != Bits2) {
 947       if (Context.Complain) {
 948         Context.Diag2(Owner2->getLocation(), diag::warn_odr_tag_type_inconsistent)
 949           << Context.C2.getTypeDeclType(Owner2);
 950         Context.Diag2(Field2->getLocation(), diag::note_odr_bit_field)
 951           << Field2->getDeclName() << Field2->getType() << Bits2;
 952         Context.Diag1(Field1->getLocation(), diag::note_odr_bit_field)
 953           << Field1->getDeclName() << Field1->getType() << Bits1;
 954       }
 955       return false;
 956     }
 957   }
 958
 959   return true;
 960 }
 961
 962 /// \brief Find the index of the given anonymous struct/union within its
 963 /// context.
 964 ///
 965 /// \returns Returns the index of this anonymous struct/union in its context,
 966 /// including the next assigned index (if none of them match). Returns an
 967 /// empty option if the context is not a record, i.e.. if the anonymous
 968 /// struct/union is at namespace or block scope.
 969 static Optional<unsigned> findAnonymousStructOrUnionIndex(RecordDecl *Anon) {
 970   ASTContext &Context = Anon->getASTContext();
 971   QualType AnonTy = Context.getRecordType(Anon);
 972
 973   RecordDecl *Owner = dyn_cast<RecordDecl>(Anon->getDeclContext());
 974   if (!Owner)
 975     return None;
 976
 977   unsigned Index = 0;
 978   for (const auto *D : Owner->noload_decls()) {
 979     const auto *F = dyn_cast<FieldDecl>(D);
 980     if (!F || !F->isAnonymousStructOrUnion())
 981       continue;
 982
 983     if (Context.hasSameType(F->getType(), AnonTy))
 984       break;
 985
 986     ++Index;
 987   }
 988
 989   return Index;
 990 }
 991
 992 /// \brief Determine structural equivalence of two records.
 993 static bool IsStructurallyEquivalent(StructuralEquivalenceContext &Context,
 994                                      RecordDecl *D1, RecordDecl *D2) {
 995   if (D1->isUnion() != D2->isUnion()) {
 996     if (Context.Complain) {
 997       Context.Diag2(D2->getLocation(), diag::warn_odr_tag_type_inconsistent)
 998         << Context.C2.getTypeDeclType(D2);
 999       Context.Diag1(D1->getLocation(), diag::note_odr_tag_kind_here)
1000         << D1->getDeclName() << (unsigned)D1->getTagKind();
1001     }
1002     return false;
1003   }
1004
1005   if (D1->isAnonymousStructOrUnion() && D2->isAnonymousStructOrUnion()) {
1006     // If both anonymous structs/unions are in a record context, make sure
1007     // they occur in the same location in the context records.
1008     if (Optional<unsigned> Index1 = findAnonymousStructOrUnionIndex(D1)) {
1009       if (Optional<unsigned> Index2 = findAnonymousStructOrUnionIndex(D2)) {
1010         if (*Index1 != *Index2)
1011           return false;
1012       }
1013     }
1014   }
1015
1016   // If both declarations are class template specializations, we know
1017   // the ODR applies, so check the template and template arguments.
1018   ClassTemplateSpecializationDecl *Spec1
1019     = dyn_cast<ClassTemplateSpecializationDecl>(D1);
1020   ClassTemplateSpecializationDecl *Spec2
1021     = dyn_cast<ClassTemplateSpecializationDecl>(D2);
1022   if (Spec1 && Spec2) {
1023     // Check that the specialized templates are the same.
1024     if (!IsStructurallyEquivalent(Context, Spec1->getSpecializedTemplate(),
1025                                   Spec2->getSpecializedTemplate()))
1026       return false;
1027
1028     // Check that the template arguments are the same.
1029     if (Spec1->getTemplateArgs().size() != Spec2->getTemplateArgs().size())
1030       return false;
1031
1032     for (unsigned I = 0, N = Spec1->getTemplateArgs().size(); I != N; ++I)
1033       if (!IsStructurallyEquivalent(Context,
1034                                     Spec1->getTemplateArgs().get(I),
1035                                     Spec2->getTemplateArgs().get(I)))
1036         return false;
1037   }
1038   // If one is a class template specialization and the other is not, these
1039   // structures are different.
1040   else if (Spec1 || Spec2)
1041     return false;
1042
1043   // Compare the definitions of these two records. If either or both are
1044   // incomplete, we assume that they are equivalent.
1045   D1 = D1->getDefinition();
1046   D2 = D2->getDefinition();
1047   if (!D1 || !D2)
1048     return true;
1049
1050   if (CXXRecordDecl *D1CXX = dyn_cast<CXXRecordDecl>(D1)) {
1051     if (CXXRecordDecl *D2CXX = dyn_cast<CXXRecordDecl>(D2)) {
1052       if (D1CXX->getNumBases() != D2CXX->getNumBases()) {
1053         if (Context.Complain) {
1054           Context.Diag2(D2->getLocation(), diag::warn_odr_tag_type_inconsistent)
1055             << Context.C2.getTypeDeclType(D2);
1056           Context.Diag2(D2->getLocation(), diag::note_odr_number_of_bases)
1057             << D2CXX->getNumBases();
1058           Context.Diag1(D1->getLocation(), diag::note_odr_number_of_bases)
1059             << D1CXX->getNumBases();
1060         }
1061         return false;
1062       }
1063
1064       // Check the base classes.
1065       for (CXXRecordDecl::base_class_iterator Base1 = D1CXX->bases_begin(),
1066                                            BaseEnd1 = D1CXX->bases_end(),
1067                                                 Base2 = D2CXX->bases_begin();
1068            Base1 != BaseEnd1;
1069            ++Base1, ++Base2) {
1070         if (!IsStructurallyEquivalent(Context,
1071                                       Base1->getType(), Base2->getType())) {
1072           if (Context.Complain) {
1073             Context.Diag2(D2->getLocation(), diag::warn_odr_tag_type_inconsistent)
1074               << Context.C2.getTypeDeclType(D2);
1075             Context.Diag2(Base2->getLocStart(), diag::note_odr_base)
1076               << Base2->getType()
1077               << Base2->getSourceRange();
1078             Context.Diag1(Base1->getLocStart(), diag::note_odr_base)
1079               << Base1->getType()
1080               << Base1->getSourceRange();
1081           }
1082           return false;
1083         }
1084
1085         // Check virtual vs. non-virtual inheritance mismatch.
1086         if (Base1->isVirtual() != Base2->isVirtual()) {
1087           if (Context.Complain) {
1088             Context.Diag2(D2->getLocation(), diag::warn_odr_tag_type_inconsistent)
1089               << Context.C2.getTypeDeclType(D2);
1090             Context.Diag2(Base2->getLocStart(),
1091                           diag::note_odr_virtual_base)
1092               << Base2->isVirtual() << Base2->getSourceRange();
1093             Context.Diag1(Base1->getLocStart(), diag::note_odr_base)
1094               << Base1->isVirtual()
1095               << Base1->getSourceRange();
1096           }
1097           return false;
1098         }
1099       }
1100     } else if (D1CXX->getNumBases() > 0) {
1101       if (Context.Complain) {
1102         Context.Diag2(D2->getLocation(), diag::warn_odr_tag_type_inconsistent)
1103           << Context.C2.getTypeDeclType(D2);
1104         const CXXBaseSpecifier *Base1 = D1CXX->bases_begin();
1105         Context.Diag1(Base1->getLocStart(), diag::note_odr_base)
1106           << Base1->getType()
1107           << Base1->getSourceRange();
1108         Context.Diag2(D2->getLocation(), diag::note_odr_missing_base);
1109       }
1110       return false;
1111     }
1112   }
1113
1114   // Check the fields for consistency.
1115   RecordDecl::field_iterator Field2 = D2->field_begin(),
1116                              Field2End = D2->field_end();
1117   for (RecordDecl::field_iterator Field1 = D1->field_begin(),
1118                                   Field1End = D1->field_end();
1119        Field1 != Field1End;
1120        ++Field1, ++Field2) {
1121     if (Field2 == Field2End) {
1122       if (Context.Complain) {
1123         Context.Diag2(D2->getLocation(), diag::warn_odr_tag_type_inconsistent)
1124           << Context.C2.getTypeDeclType(D2);
1125         Context.Diag1(Field1->getLocation(), diag::note_odr_field)
1126           << Field1->getDeclName() << Field1->getType();
1127         Context.Diag2(D2->getLocation(), diag::note_odr_missing_field);
1128       }
1129       return false;
1130     }
1131
1132     if (!IsStructurallyEquivalent(Context, *Field1, *Field2))
1133       return false;
1134   }
1135
1136   if (Field2 != Field2End) {
1137     if (Context.Complain) {
1138       Context.Diag2(D2->getLocation(), diag::warn_odr_tag_type_inconsistent)
1139         << Context.C2.getTypeDeclType(D2);
1140       Context.Diag2(Field2->getLocation(), diag::note_odr_field)
1141         << Field2->getDeclName() << Field2->getType();
1142       Context.Diag1(D1->getLocation(), diag::note_odr_missing_field);
1143     }
1144     return false;
1145   }
1146
1147   return true;
1148 }
1149
1150 /// \brief Determine structural equivalence of two enums.
1151 static bool IsStructurallyEquivalent(StructuralEquivalenceContext &Context,
1152                                      EnumDecl *D1, EnumDecl *D2) {
1153   EnumDecl::enumerator_iterator EC2 = D2->enumerator_begin(),
1154                              EC2End = D2->enumerator_end();
1155   for (EnumDecl::enumerator_iterator EC1 = D1->enumerator_begin(),
1156                                   EC1End = D1->enumerator_end();
1157        EC1 != EC1End; ++EC1, ++EC2) {
1158     if (EC2 == EC2End) {
1159       if (Context.Complain) {
1160         Context.Diag2(D2->getLocation(), diag::warn_odr_tag_type_inconsistent)
1161           << Context.C2.getTypeDeclType(D2);
1162         Context.Diag1(EC1->getLocation(), diag::note_odr_enumerator)
1163           << EC1->getDeclName()
1164           << EC1->getInitVal().toString(10);
1165         Context.Diag2(D2->getLocation(), diag::note_odr_missing_enumerator);
1166       }
1167       return false;
1168     }
1169
1170     llvm::APSInt Val1 = EC1->getInitVal();
1171     llvm::APSInt Val2 = EC2->getInitVal();
1172     if (!llvm::APSInt::isSameValue(Val1, Val2) ||
1173         !IsStructurallyEquivalent(EC1->getIdentifier(), EC2->getIdentifier())) {
1174       if (Context.Complain) {
1175         Context.Diag2(D2->getLocation(), diag::warn_odr_tag_type_inconsistent)
1176           << Context.C2.getTypeDeclType(D2);
1177         Context.Diag2(EC2->getLocation(), diag::note_odr_enumerator)
1178           << EC2->getDeclName()
1179           << EC2->getInitVal().toString(10);
1180         Context.Diag1(EC1->getLocation(), diag::note_odr_enumerator)
1181           << EC1->getDeclName()
1182           << EC1->getInitVal().toString(10);
1183       }
1184       return false;
1185     }
1186   }
1187
1188   if (EC2 != EC2End) {
1189     if (Context.Complain) {
1190       Context.Diag2(D2->getLocation(), diag::warn_odr_tag_type_inconsistent)
1191         << Context.C2.getTypeDeclType(D2);
1192       Context.Diag2(EC2->getLocation(), diag::note_odr_enumerator)
1193         << EC2->getDeclName()
1194         << EC2->getInitVal().toString(10);
1195       Context.Diag1(D1->getLocation(), diag::note_odr_missing_enumerator);
1196     }
1197     return false;
1198   }
1199
1200   return true;
1201 }
1202
1203 static bool IsStructurallyEquivalent(StructuralEquivalenceContext &Context,
1204                                      TemplateParameterList *Params1,
1205                                      TemplateParameterList *Params2) {
1206   if (Params1->size() != Params2->size()) {
1207     if (Context.Complain) {
1208       Context.Diag2(Params2->getTemplateLoc(),
1209                     diag::err_odr_different_num_template_parameters)
1210         << Params1->size() << Params2->size();
1211       Context.Diag1(Params1->getTemplateLoc(),
1212                     diag::note_odr_template_parameter_list);
1213     }
1214     return false;
1215   }
1216
1217   for (unsigned I = 0, N = Params1->size(); I != N; ++I) {
1218     if (Params1->getParam(I)->getKind() != Params2->getParam(I)->getKind()) {
1219       if (Context.Complain) {
1220         Context.Diag2(Params2->getParam(I)->getLocation(),
1221                       diag::err_odr_different_template_parameter_kind);
1222         Context.Diag1(Params1->getParam(I)->getLocation(),
1223                       diag::note_odr_template_parameter_here);
1224       }
1225       return false;
1226     }
1227
1228     if (!Context.IsStructurallyEquivalent(Params1->getParam(I),
1229                                           Params2->getParam(I))) {
1230
1231       return false;
1232     }
1233   }
1234
1235   return true;
1236 }
1237
1238 static bool IsStructurallyEquivalent(StructuralEquivalenceContext &Context,
1239                                      TemplateTypeParmDecl *D1,
1240                                      TemplateTypeParmDecl *D2) {
1241   if (D1->isParameterPack() != D2->isParameterPack()) {
1242     if (Context.Complain) {
1243       Context.Diag2(D2->getLocation(), diag::err_odr_parameter_pack_non_pack)
1244         << D2->isParameterPack();
1245       Context.Diag1(D1->getLocation(), diag::note_odr_parameter_pack_non_pack)
1246         << D1->isParameterPack();
1247     }
1248     return false;
1249   }
1250
1251   return true;
1252 }
1253
1254 static bool IsStructurallyEquivalent(StructuralEquivalenceContext &Context,
1255                                      NonTypeTemplateParmDecl *D1,
1256                                      NonTypeTemplateParmDecl *D2) {
1257   if (D1->isParameterPack() != D2->isParameterPack()) {
1258     if (Context.Complain) {
1259       Context.Diag2(D2->getLocation(), diag::err_odr_parameter_pack_non_pack)
1260         << D2->isParameterPack();
1261       Context.Diag1(D1->getLocation(), diag::note_odr_parameter_pack_non_pack)
1262         << D1->isParameterPack();
1263     }
1264     return false;
1265   }
1266
1267   // Check types.
1268   if (!Context.IsStructurallyEquivalent(D1->getType(), D2->getType())) {
1269     if (Context.Complain) {
1270       Context.Diag2(D2->getLocation(),
1271                     diag::err_odr_non_type_parameter_type_inconsistent)
1272         << D2->getType() << D1->getType();
1273       Context.Diag1(D1->getLocation(), diag::note_odr_value_here)
1274         << D1->getType();
1275     }
1276     return false;
1277   }
1278
1279   return true;
1280 }
1281
1282 static bool IsStructurallyEquivalent(StructuralEquivalenceContext &Context,
1283                                      TemplateTemplateParmDecl *D1,
1284                                      TemplateTemplateParmDecl *D2) {
1285   if (D1->isParameterPack() != D2->isParameterPack()) {
1286     if (Context.Complain) {
1287       Context.Diag2(D2->getLocation(), diag::err_odr_parameter_pack_non_pack)
1288         << D2->isParameterPack();
1289       Context.Diag1(D1->getLocation(), diag::note_odr_parameter_pack_non_pack)
1290         << D1->isParameterPack();
1291     }
1292     return false;
1293   }
1294
1295   // Check template parameter lists.
1296   return IsStructurallyEquivalent(Context, D1->getTemplateParameters(),
1297                                   D2->getTemplateParameters());
1298 }
1299
1300 static bool IsStructurallyEquivalent(StructuralEquivalenceContext &Context,
1301                                      ClassTemplateDecl *D1,
1302                                      ClassTemplateDecl *D2) {
1303   // Check template parameters.
1304   if (!IsStructurallyEquivalent(Context,
1305                                 D1->getTemplateParameters(),
1306                                 D2->getTemplateParameters()))
1307     return false;
1308
1309   // Check the templated declaration.
1310   return Context.IsStructurallyEquivalent(D1->getTemplatedDecl(),
1311                                           D2->getTemplatedDecl());
1312 }
1313
1314 /// \brief Determine structural equivalence of two declarations.
1315 static bool IsStructurallyEquivalent(StructuralEquivalenceContext &Context,
1316                                      Decl *D1, Decl *D2) {
1317   // FIXME: Check for known structural equivalences via a callback of some sort.
1318
1319   // Check whether we already know that these two declarations are not
1320   // structurally equivalent.
1321   if (Context.NonEquivalentDecls.count(std::make_pair(D1->getCanonicalDecl(),
1322                                                       D2->getCanonicalDecl())))
1323     return false;
1324
1325   // Determine whether we've already produced a tentative equivalence for D1.
1326   Decl *&EquivToD1 = Context.TentativeEquivalences[D1->getCanonicalDecl()];
1327   if (EquivToD1)
1328     return EquivToD1 == D2->getCanonicalDecl();
1329
1330   // Produce a tentative equivalence D1 <-> D2, which will be checked later.
1331   EquivToD1 = D2->getCanonicalDecl();
1332   Context.DeclsToCheck.push_back(D1->getCanonicalDecl());
1333   return true;
1334 }
1335
1336 bool StructuralEquivalenceContext::IsStructurallyEquivalent(Decl *D1,
1337                                                             Decl *D2) {
1338   if (!::IsStructurallyEquivalent(*this, D1, D2))
1339     return false;
1340
1341   return !Finish();
1342 }
1343
1344 bool StructuralEquivalenceContext::IsStructurallyEquivalent(QualType T1,
1345                                                             QualType T2) {
1346   if (!::IsStructurallyEquivalent(*this, T1, T2))
1347     return false;
1348
1349   return !Finish();
1350 }
1351
1352 bool StructuralEquivalenceContext::Finish() {
1353   while (!DeclsToCheck.empty()) {
1354     // Check the next declaration.
1355     Decl *D1 = DeclsToCheck.front();
1356     DeclsToCheck.pop_front();
1357
1358     Decl *D2 = TentativeEquivalences[D1];
1359     assert(D2 && "Unrecorded tentative equivalence?");
1360
1361     bool Equivalent = true;
1362
1363     // FIXME: Switch on all declaration kinds. For now, we're just going to
1364     // check the obvious ones.
1365     if (RecordDecl *Record1 = dyn_cast<RecordDecl>(D1)) {
1366       if (RecordDecl *Record2 = dyn_cast<RecordDecl>(D2)) {
1367         // Check for equivalent structure names.
1368         IdentifierInfo *Name1 = Record1->getIdentifier();
1369         if (!Name1 && Record1->getTypedefNameForAnonDecl())
1370           Name1 = Record1->getTypedefNameForAnonDecl()->getIdentifier();
1371         IdentifierInfo *Name2 = Record2->getIdentifier();
1372         if (!Name2 && Record2->getTypedefNameForAnonDecl())
1373           Name2 = Record2->getTypedefNameForAnonDecl()->getIdentifier();
1374         if (!::IsStructurallyEquivalent(Name1, Name2) ||
1375             !::IsStructurallyEquivalent(*this, Record1, Record2))
1376           Equivalent = false;
1377       } else {
1378         // Record/non-record mismatch.
1379         Equivalent = false;
1380       }
1381     } else if (EnumDecl *Enum1 = dyn_cast<EnumDecl>(D1)) {
1382       if (EnumDecl *Enum2 = dyn_cast<EnumDecl>(D2)) {
1383         // Check for equivalent enum names.
1384         IdentifierInfo *Name1 = Enum1->getIdentifier();
1385         if (!Name1 && Enum1->getTypedefNameForAnonDecl())
1386           Name1 = Enum1->getTypedefNameForAnonDecl()->getIdentifier();
1387         IdentifierInfo *Name2 = Enum2->getIdentifier();
1388         if (!Name2 && Enum2->getTypedefNameForAnonDecl())
1389           Name2 = Enum2->getTypedefNameForAnonDecl()->getIdentifier();
1390         if (!::IsStructurallyEquivalent(Name1, Name2) ||
1391             !::IsStructurallyEquivalent(*this, Enum1, Enum2))
1392           Equivalent = false;
1393       } else {
1394         // Enum/non-enum mismatch
1395         Equivalent = false;
1396       }
1397     } else if (TypedefNameDecl *Typedef1 = dyn_cast<TypedefNameDecl>(D1)) {
1398       if (TypedefNameDecl *Typedef2 = dyn_cast<TypedefNameDecl>(D2)) {
1399         if (!::IsStructurallyEquivalent(Typedef1->getIdentifier(),
1400                                         Typedef2->getIdentifier()) ||
1401             !::IsStructurallyEquivalent(*this,
1402                                         Typedef1->getUnderlyingType(),
1403                                         Typedef2->getUnderlyingType()))
1404           Equivalent = false;
1405       } else {
1406         // Typedef/non-typedef mismatch.
1407         Equivalent = false;
1408       }
1409     } else if (ClassTemplateDecl *ClassTemplate1
1410                                            = dyn_cast<ClassTemplateDecl>(D1)) {
1411       if (ClassTemplateDecl *ClassTemplate2 = dyn_cast<ClassTemplateDecl>(D2)) {
1412         if (!::IsStructurallyEquivalent(ClassTemplate1->getIdentifier(),
1413                                         ClassTemplate2->getIdentifier()) ||
1414             !::IsStructurallyEquivalent(*this, ClassTemplate1, ClassTemplate2))
1415           Equivalent = false;
1416       } else {
1417         // Class template/non-class-template mismatch.
1418         Equivalent = false;
1419       }
1420     } else if (TemplateTypeParmDecl *TTP1= dyn_cast<TemplateTypeParmDecl>(D1)) {
1421       if (TemplateTypeParmDecl *TTP2 = dyn_cast<TemplateTypeParmDecl>(D2)) {
1422         if (!::IsStructurallyEquivalent(*this, TTP1, TTP2))
1423           Equivalent = false;
1424       } else {
1425         // Kind mismatch.
1426         Equivalent = false;
1427       }
1428     } else if (NonTypeTemplateParmDecl *NTTP1
1429                                      = dyn_cast<NonTypeTemplateParmDecl>(D1)) {
1430       if (NonTypeTemplateParmDecl *NTTP2
1431                                       = dyn_cast<NonTypeTemplateParmDecl>(D2)) {
1432         if (!::IsStructurallyEquivalent(*this, NTTP1, NTTP2))
1433           Equivalent = false;
1434       } else {
1435         // Kind mismatch.
1436         Equivalent = false;
1437       }
1438     } else if (TemplateTemplateParmDecl *TTP1
1439                                   = dyn_cast<TemplateTemplateParmDecl>(D1)) {
1440       if (TemplateTemplateParmDecl *TTP2
1441                                     = dyn_cast<TemplateTemplateParmDecl>(D2)) {
1442         if (!::IsStructurallyEquivalent(*this, TTP1, TTP2))
1443           Equivalent = false;
1444       } else {
1445         // Kind mismatch.
1446         Equivalent = false;
1447       }
1448     }
1449
1450     if (!Equivalent) {
1451       // Note that these two declarations are not equivalent (and we already
1452       // know about it).
1453       NonEquivalentDecls.insert(std::make_pair(D1->getCanonicalDecl(),
1454                                                D2->getCanonicalDecl()));
1455       return true;
1456     }
1457     // FIXME: Check other declaration kinds!
1458   }
1459
1460   return false;
1461 }
1462
1463 //----------------------------------------------------------------------------
1464 // Import Types
1465 //----------------------------------------------------------------------------
1466
1467 QualType ASTNodeImporter::VisitType(const Type *T) {
1468   Importer.FromDiag(SourceLocation(), diag::err_unsupported_ast_node)
1469     << T->getTypeClassName();
1470   return QualType();
1471 }
1472
1473 QualType ASTNodeImporter::VisitBuiltinType(const BuiltinType *T) {
1474   switch (T->getKind()) {
1475 #define SHARED_SINGLETON_TYPE(Expansion)
1476 #define BUILTIN_TYPE(Id, SingletonId) \
1477   case BuiltinType::Id: return Importer.getToContext().SingletonId;
1478 #include "clang/AST/BuiltinTypes.def"
1479
1480   // FIXME: for Char16, Char32, and NullPtr, make sure that the "to"
1481   // context supports C++.
1482
1483   // FIXME: for ObjCId, ObjCClass, and ObjCSel, make sure that the "to"
1484   // context supports ObjC.
1485
1486   case BuiltinType::Char_U:
1487     // The context we're importing from has an unsigned 'char'. If we're
1488     // importing into a context with a signed 'char', translate to
1489     // 'unsigned char' instead.
1490     if (Importer.getToContext().getLangOpts().CharIsSigned)
1491       return Importer.getToContext().UnsignedCharTy;
1492
1493     return Importer.getToContext().CharTy;
1494
1495   case BuiltinType::Char_S:
1496     // The context we're importing from has an unsigned 'char'. If we're
1497     // importing into a context with a signed 'char', translate to
1498     // 'unsigned char' instead.
1499     if (!Importer.getToContext().getLangOpts().CharIsSigned)
1500       return Importer.getToContext().SignedCharTy;
1501
1502     return Importer.getToContext().CharTy;
1503
1504   case BuiltinType::WChar_S:
1505   case BuiltinType::WChar_U:
1506     // FIXME: If not in C++, shall we translate to the C equivalent of
1507     // wchar_t?
1508     return Importer.getToContext().WCharTy;
1509   }
1510
1511   llvm_unreachable("Invalid BuiltinType Kind!");
1512 }
1513
1514 QualType ASTNodeImporter::VisitComplexType(const ComplexType *T) {
1515   QualType ToElementType = Importer.Import(T->getElementType());
1516   if (ToElementType.isNull())
1517     return QualType();
1518
1519   return Importer.getToContext().getComplexType(ToElementType);
1520 }
1521
1522 QualType ASTNodeImporter::VisitPointerType(const PointerType *T) {
1523   QualType ToPointeeType = Importer.Import(T->getPointeeType());
1524   if (ToPointeeType.isNull())
1525     return QualType();
1526
1527   return Importer.getToContext().getPointerType(ToPointeeType);
1528 }
1529
1530 QualType ASTNodeImporter::VisitBlockPointerType(const BlockPointerType *T) {
1531   // FIXME: Check for blocks support in "to" context.
1532   QualType ToPointeeType = Importer.Import(T->getPointeeType());
1533   if (ToPointeeType.isNull())
1534     return QualType();
1535
1536   return Importer.getToContext().getBlockPointerType(ToPointeeType);
1537 }
1538
1539 QualType
1540 ASTNodeImporter::VisitLValueReferenceType(const LValueReferenceType *T) {
1541   // FIXME: Check for C++ support in "to" context.
1542   QualType ToPointeeType = Importer.Import(T->getPointeeTypeAsWritten());
1543   if (ToPointeeType.isNull())
1544     return QualType();
1545
1546   return Importer.getToContext().getLValueReferenceType(ToPointeeType);
1547 }
1548
1549 QualType
1550 ASTNodeImporter::VisitRValueReferenceType(const RValueReferenceType *T) {
1551   // FIXME: Check for C++0x support in "to" context.
1552   QualType ToPointeeType = Importer.Import(T->getPointeeTypeAsWritten());
1553   if (ToPointeeType.isNull())
1554     return QualType();
1555
1556   return Importer.getToContext().getRValueReferenceType(ToPointeeType);
1557 }
1558
1559 QualType ASTNodeImporter::VisitMemberPointerType(const MemberPointerType *T) {
1560   // FIXME: Check for C++ support in "to" context.
1561   QualType ToPointeeType = Importer.Import(T->getPointeeType());
1562   if (ToPointeeType.isNull())
1563     return QualType();
1564
1565   QualType ClassType = Importer.Import(QualType(T->getClass(), 0));
1566   return Importer.getToContext().getMemberPointerType(ToPointeeType,
1567                                                       ClassType.getTypePtr());
1568 }
1569
1570 QualType ASTNodeImporter::VisitConstantArrayType(const ConstantArrayType *T) {
1571   QualType ToElementType = Importer.Import(T->getElementType());
1572   if (ToElementType.isNull())
1573     return QualType();
1574
1575   return Importer.getToContext().getConstantArrayType(ToElementType,
1576                                                       T->getSize(),
1577                                                       T->getSizeModifier(),
1578                                                T->getIndexTypeCVRQualifiers());
1579 }
1580
1581 QualType
1582 ASTNodeImporter::VisitIncompleteArrayType(const IncompleteArrayType *T) {
1583   QualType ToElementType = Importer.Import(T->getElementType());
1584   if (ToElementType.isNull())
1585     return QualType();
1586
1587   return Importer.getToContext().getIncompleteArrayType(ToElementType,
1588                                                         T->getSizeModifier(),
1589                                                 T->getIndexTypeCVRQualifiers());
1590 }
1591
1592 QualType ASTNodeImporter::VisitVariableArrayType(const VariableArrayType *T) {
1593   QualType ToElementType = Importer.Import(T->getElementType());
1594   if (ToElementType.isNull())
1595     return QualType();
1596
1597   Expr *Size = Importer.Import(T->getSizeExpr());
1598   if (!Size)
1599     return QualType();
1600
1601   SourceRange Brackets = Importer.Import(T->getBracketsRange());
1602   return Importer.getToContext().getVariableArrayType(ToElementType, Size,
1603                                                       T->getSizeModifier(),
1604                                                 T->getIndexTypeCVRQualifiers(),
1605                                                       Brackets);
1606 }
1607
1608 QualType ASTNodeImporter::VisitVectorType(const VectorType *T) {
1609   QualType ToElementType = Importer.Import(T->getElementType());
1610   if (ToElementType.isNull())
1611     return QualType();
1612
1613   return Importer.getToContext().getVectorType(ToElementType,
1614                                                T->getNumElements(),
1615                                                T->getVectorKind());
1616 }
1617
1618 QualType ASTNodeImporter::VisitExtVectorType(const ExtVectorType *T) {
1619   QualType ToElementType = Importer.Import(T->getElementType());
1620   if (ToElementType.isNull())
1621     return QualType();
1622
1623   return Importer.getToContext().getExtVectorType(ToElementType,
1624                                                   T->getNumElements());
1625 }
1626
1627 QualType
1628 ASTNodeImporter::VisitFunctionNoProtoType(const FunctionNoProtoType *T) {
1629   // FIXME: What happens if we're importing a function without a prototype
1630   // into C++? Should we make it variadic?
1631   QualType ToResultType = Importer.Import(T->getReturnType());
1632   if (ToResultType.isNull())
1633     return QualType();
1634
1635   return Importer.getToContext().getFunctionNoProtoType(ToResultType,
1636                                                         T->getExtInfo());
1637 }
1638
1639 QualType ASTNodeImporter::VisitFunctionProtoType(const FunctionProtoType *T) {
1640   QualType ToResultType = Importer.Import(T->getReturnType());
1641   if (ToResultType.isNull())
1642     return QualType();
1643
1644   // Import argument types
1645   SmallVector<QualType, 4> ArgTypes;
1646   for (const auto &A : T->param_types()) {
1647     QualType ArgType = Importer.Import(A);
1648     if (ArgType.isNull())
1649       return QualType();
1650     ArgTypes.push_back(ArgType);
1651   }
1652
1653   // Import exception types
1654   SmallVector<QualType, 4> ExceptionTypes;
1655   for (const auto &E : T->exceptions()) {
1656     QualType ExceptionType = Importer.Import(E);
1657     if (ExceptionType.isNull())
1658       return QualType();
1659     ExceptionTypes.push_back(ExceptionType);
1660   }
1661
1662   FunctionProtoType::ExtProtoInfo FromEPI = T->getExtProtoInfo();
1663   FunctionProtoType::ExtProtoInfo ToEPI;
1664
1665   ToEPI.ExtInfo = FromEPI.ExtInfo;
1666   ToEPI.Variadic = FromEPI.Variadic;
1667   ToEPI.HasTrailingReturn = FromEPI.HasTrailingReturn;
1668   ToEPI.TypeQuals = FromEPI.TypeQuals;
1669   ToEPI.RefQualifier = FromEPI.RefQualifier;
1670   ToEPI.ExceptionSpec.Type = FromEPI.ExceptionSpec.Type;
1671   ToEPI.ExceptionSpec.Exceptions = ExceptionTypes;
1672   ToEPI.ExceptionSpec.NoexceptExpr =
1673       Importer.Import(FromEPI.ExceptionSpec.NoexceptExpr);
1674   ToEPI.ExceptionSpec.SourceDecl = cast_or_null<FunctionDecl>(
1675       Importer.Import(FromEPI.ExceptionSpec.SourceDecl));
1676   ToEPI.ExceptionSpec.SourceTemplate = cast_or_null<FunctionDecl>(
1677       Importer.Import(FromEPI.ExceptionSpec.SourceTemplate));
1678
1679   return Importer.getToContext().getFunctionType(ToResultType, ArgTypes, ToEPI);
1680 }
1681
1682 QualType ASTNodeImporter::VisitParenType(const ParenType *T) {
1683   QualType ToInnerType = Importer.Import(T->getInnerType());
1684   if (ToInnerType.isNull())
1685     return QualType();
1686
1687   return Importer.getToContext().getParenType(ToInnerType);
1688 }
1689
1690 QualType ASTNodeImporter::VisitTypedefType(const TypedefType *T) {
1691   TypedefNameDecl *ToDecl
1692              = dyn_cast_or_null<TypedefNameDecl>(Importer.Import(T->getDecl()));
1693   if (!ToDecl)
1694     return QualType();
1695
1696   return Importer.getToContext().getTypeDeclType(ToDecl);
1697 }
1698
1699 QualType ASTNodeImporter::VisitTypeOfExprType(const TypeOfExprType *T) {
1700   Expr *ToExpr = Importer.Import(T->getUnderlyingExpr());
1701   if (!ToExpr)
1702     return QualType();
1703
1704   return Importer.getToContext().getTypeOfExprType(ToExpr);
1705 }
1706
1707 QualType ASTNodeImporter::VisitTypeOfType(const TypeOfType *T) {
1708   QualType ToUnderlyingType = Importer.Import(T->getUnderlyingType());
1709   if (ToUnderlyingType.isNull())
1710     return QualType();
1711
1712   return Importer.getToContext().getTypeOfType(ToUnderlyingType);
1713 }
1714
1715 QualType ASTNodeImporter::VisitDecltypeType(const DecltypeType *T) {
1716   // FIXME: Make sure that the "to" context supports C++0x!
1717   Expr *ToExpr = Importer.Import(T->getUnderlyingExpr());
1718   if (!ToExpr)
1719     return QualType();
1720
1721   QualType UnderlyingType = Importer.Import(T->getUnderlyingType());
1722   if (UnderlyingType.isNull())
1723     return QualType();
1724
1725   return Importer.getToContext().getDecltypeType(ToExpr, UnderlyingType);
1726 }
1727
1728 QualType ASTNodeImporter::VisitUnaryTransformType(const UnaryTransformType *T) {
1729   QualType ToBaseType = Importer.Import(T->getBaseType());
1730   QualType ToUnderlyingType = Importer.Import(T->getUnderlyingType());
1731   if (ToBaseType.isNull() || ToUnderlyingType.isNull())
1732     return QualType();
1733
1734   return Importer.getToContext().getUnaryTransformType(ToBaseType,
1735                                                        ToUnderlyingType,
1736                                                        T->getUTTKind());
1737 }
1738
1739 QualType ASTNodeImporter::VisitAutoType(const AutoType *T) {
1740   // FIXME: Make sure that the "to" context supports C++11!
1741   QualType FromDeduced = T->getDeducedType();
1742   QualType ToDeduced;
1743   if (!FromDeduced.isNull()) {
1744     ToDeduced = Importer.Import(FromDeduced);
1745     if (ToDeduced.isNull())
1746       return QualType();
1747   }
1748
1749   return Importer.getToContext().getAutoType(ToDeduced, T->isDecltypeAuto(),
1750                                              /*IsDependent*/false);
1751 }
1752
1753 QualType ASTNodeImporter::VisitRecordType(const RecordType *T) {
1754   RecordDecl *ToDecl
1755     = dyn_cast_or_null<RecordDecl>(Importer.Import(T->getDecl()));
1756   if (!ToDecl)
1757     return QualType();
1758
1759   return Importer.getToContext().getTagDeclType(ToDecl);
1760 }
1761
1762 QualType ASTNodeImporter::VisitEnumType(const EnumType *T) {
1763   EnumDecl *ToDecl
1764     = dyn_cast_or_null<EnumDecl>(Importer.Import(T->getDecl()));
1765   if (!ToDecl)
1766     return QualType();
1767
1768   return Importer.getToContext().getTagDeclType(ToDecl);
1769 }
1770
1771 QualType ASTNodeImporter::VisitAttributedType(const AttributedType *T) {
1772   QualType FromModifiedType = T->getModifiedType();
1773   QualType FromEquivalentType = T->getEquivalentType();
1774   QualType ToModifiedType;
1775   QualType ToEquivalentType;
1776
1777   if (!FromModifiedType.isNull()) {
1778     ToModifiedType = Importer.Import(FromModifiedType);
1779     if (ToModifiedType.isNull())
1780       return QualType();
1781   }
1782   if (!FromEquivalentType.isNull()) {
1783     ToEquivalentType = Importer.Import(FromEquivalentType);
1784     if (ToEquivalentType.isNull())
1785       return QualType();
1786   }
1787
1788   return Importer.getToContext().getAttributedType(T->getAttrKind(),
1789     ToModifiedType, ToEquivalentType);
1790 }
1791
1792 QualType ASTNodeImporter::VisitTemplateSpecializationType(
1793                                        const TemplateSpecializationType *T) {
1794   TemplateName ToTemplate = Importer.Import(T->getTemplateName());
1795   if (ToTemplate.isNull())
1796     return QualType();
1797
1798   SmallVector<TemplateArgument, 2> ToTemplateArgs;
1799   if (ImportTemplateArguments(T->getArgs(), T->getNumArgs(), ToTemplateArgs))
1800     return QualType();
1801
1802   QualType ToCanonType;
1803   if (!QualType(T, 0).isCanonical()) {
1804     QualType FromCanonType
1805       = Importer.getFromContext().getCanonicalType(QualType(T, 0));
1806     ToCanonType =Importer.Import(FromCanonType);
1807     if (ToCanonType.isNull())
1808       return QualType();
1809   }
1810   return Importer.getToContext().getTemplateSpecializationType(ToTemplate,
1811                                                          ToTemplateArgs.data(),
1812                                                          ToTemplateArgs.size(),
1813                                                                ToCanonType);
1814 }
1815
1816 QualType ASTNodeImporter::VisitElaboratedType(const ElaboratedType *T) {
1817   NestedNameSpecifier *ToQualifier = nullptr;
1818   // Note: the qualifier in an ElaboratedType is optional.
1819   if (T->getQualifier()) {
1820     ToQualifier = Importer.Import(T->getQualifier());
1821     if (!ToQualifier)
1822       return QualType();
1823   }
1824
1825   QualType ToNamedType = Importer.Import(T->getNamedType());
1826   if (ToNamedType.isNull())
1827     return QualType();
1828
1829   return Importer.getToContext().getElaboratedType(T->getKeyword(),
1830                                                    ToQualifier, ToNamedType);
1831 }
1832
1833 QualType ASTNodeImporter::VisitObjCInterfaceType(const ObjCInterfaceType *T) {
1834   ObjCInterfaceDecl *Class
1835     = dyn_cast_or_null<ObjCInterfaceDecl>(Importer.Import(T->getDecl()));
1836   if (!Class)
1837     return QualType();
1838
1839   return Importer.getToContext().getObjCInterfaceType(Class);
1840 }
1841
1842 QualType ASTNodeImporter::VisitObjCObjectType(const ObjCObjectType *T) {
1843   QualType ToBaseType = Importer.Import(T->getBaseType());
1844   if (ToBaseType.isNull())
1845     return QualType();
1846
1847   SmallVector<QualType, 4> TypeArgs;
1848   for (auto TypeArg : T->getTypeArgs()) {
1849     QualType ImportedTypeArg = Importer.Import(TypeArg);
1850     if (ImportedTypeArg.isNull())
1851       return QualType();
1852
1853     TypeArgs.push_back(ImportedTypeArg);
1854   }
1855
1856
1857   SmallVector<ObjCProtocolDecl *, 4> Protocols;
1858   for (auto *P : T->quals()) {
1859     ObjCProtocolDecl *Protocol
1860       = dyn_cast_or_null<ObjCProtocolDecl>(Importer.Import(P));
1861     if (!Protocol)
1862       return QualType();
1863     Protocols.push_back(Protocol);
1864   }
1865
1866   return Importer.getToContext().getObjCObjectType(ToBaseType, TypeArgs,
1867                                                    Protocols);
1868 }
1869
1870 QualType
1871 ASTNodeImporter::VisitObjCObjectPointerType(const ObjCObjectPointerType *T) {
1872   QualType ToPointeeType = Importer.Import(T->getPointeeType());
1873   if (ToPointeeType.isNull())
1874     return QualType();
1875
1876   return Importer.getToContext().getObjCObjectPointerType(ToPointeeType);
1877 }
1878
1879 //----------------------------------------------------------------------------
1880 // Import Declarations
1881 //----------------------------------------------------------------------------
1882 bool ASTNodeImporter::ImportDeclParts(NamedDecl *D, DeclContext *&DC,
1883                                       DeclContext *&LexicalDC,
1884                                       DeclarationName &Name,
1885                                       NamedDecl *&ToD,
1886                                       SourceLocation &Loc) {
1887   // Import the context of this declaration.
1888   DC = Importer.ImportContext(D->getDeclContext());
1889   if (!DC)
1890     return true;
1891
1892   LexicalDC = DC;
1893   if (D->getDeclContext() != D->getLexicalDeclContext()) {
1894     LexicalDC = Importer.ImportContext(D->getLexicalDeclContext());
1895     if (!LexicalDC)
1896       return true;
1897   }
1898
1899   // Import the name of this declaration.
1900   Name = Importer.Import(D->getDeclName());
1901   if (D->getDeclName() && !Name)
1902     return true;
1903
1904   // Import the location of this declaration.
1905   Loc = Importer.Import(D->getLocation());
1906   ToD = cast_or_null<NamedDecl>(Importer.GetAlreadyImportedOrNull(D));
1907   return false;
1908 }
1909
1910 void ASTNodeImporter::ImportDefinitionIfNeeded(Decl *FromD, Decl *ToD) {
1911   if (!FromD)
1912     return;
1913
1914   if (!ToD) {
1915     ToD = Importer.Import(FromD);
1916     if (!ToD)
1917       return;
1918   }
1919
1920   if (RecordDecl *FromRecord = dyn_cast<RecordDecl>(FromD)) {
1921     if (RecordDecl *ToRecord = cast_or_null<RecordDecl>(ToD)) {
1922       if (FromRecord->getDefinition() && FromRecord->isCompleteDefinition() && !ToRecord->getDefinition()) {
1923         ImportDefinition(FromRecord, ToRecord);
1924       }
1925     }
1926     return;
1927   }
1928
1929   if (EnumDecl *FromEnum = dyn_cast<EnumDecl>(FromD)) {
1930     if (EnumDecl *ToEnum = cast_or_null<EnumDecl>(ToD)) {
1931       if (FromEnum->getDefinition() && !ToEnum->getDefinition()) {
1932         ImportDefinition(FromEnum, ToEnum);
1933       }
1934     }
1935     return;
1936   }
1937 }
1938
1939 void
1940 ASTNodeImporter::ImportDeclarationNameLoc(const DeclarationNameInfo &From,
1941                                           DeclarationNameInfo& To) {
1942   // NOTE: To.Name and To.Loc are already imported.
1943   // We only have to import To.LocInfo.
1944   switch (To.getName().getNameKind()) {
1945   case DeclarationName::Identifier:
1946   case DeclarationName::ObjCZeroArgSelector:
1947   case DeclarationName::ObjCOneArgSelector:
1948   case DeclarationName::ObjCMultiArgSelector:
1949   case DeclarationName::CXXUsingDirective:
1950     return;
1951
1952   case DeclarationName::CXXOperatorName: {
1953     SourceRange Range = From.getCXXOperatorNameRange();
1954     To.setCXXOperatorNameRange(Importer.Import(Range));
1955     return;
1956   }
1957   case DeclarationName::CXXLiteralOperatorName: {
1958     SourceLocation Loc = From.getCXXLiteralOperatorNameLoc();
1959     To.setCXXLiteralOperatorNameLoc(Importer.Import(Loc));
1960     return;
1961   }
1962   case DeclarationName::CXXConstructorName:
1963   case DeclarationName::CXXDestructorName:
1964   case DeclarationName::CXXConversionFunctionName: {
1965     TypeSourceInfo *FromTInfo = From.getNamedTypeInfo();
1966     To.setNamedTypeInfo(Importer.Import(FromTInfo));
1967     return;
1968   }
1969   }
1970   llvm_unreachable("Unknown name kind.");
1971 }
1972
1973 void ASTNodeImporter::ImportDeclContext(DeclContext *FromDC, bool ForceImport) {
1974   if (Importer.isMinimalImport() && !ForceImport) {
1975     Importer.ImportContext(FromDC);
1976     return;
1977   }
1978
1979   for (auto *From : FromDC->decls())
1980     Importer.Import(From);
1981 }
1982
1983 bool ASTNodeImporter::ImportDefinition(RecordDecl *From, RecordDecl *To,
1984                                        ImportDefinitionKind Kind) {
1985   if (To->getDefinition() || To->isBeingDefined()) {
1986     if (Kind == IDK_Everything)
1987       ImportDeclContext(From, /*ForceImport=*/true);
1988
1989     return false;
1990   }
1991
1992   To->startDefinition();
1993
1994   // Add base classes.
1995   if (CXXRecordDecl *ToCXX = dyn_cast<CXXRecordDecl>(To)) {
1996     CXXRecordDecl *FromCXX = cast<CXXRecordDecl>(From);
1997
1998     struct CXXRecordDecl::DefinitionData &ToData = ToCXX->data();
1999     struct CXXRecordDecl::DefinitionData &FromData = FromCXX->data();
2000     ToData.UserDeclaredConstructor = FromData.UserDeclaredConstructor;
2001     ToData.UserDeclaredSpecialMembers = FromData.UserDeclaredSpecialMembers;
2002     ToData.Aggregate = FromData.Aggregate;
2003     ToData.PlainOldData = FromData.PlainOldData;
2004     ToData.Empty = FromData.Empty;
2005     ToData.Polymorphic = FromData.Polymorphic;
2006     ToData.Abstract = FromData.Abstract;
2007     ToData.IsStandardLayout = FromData.IsStandardLayout;
2008     ToData.HasNoNonEmptyBases = FromData.HasNoNonEmptyBases;
2009     ToData.HasPrivateFields = FromData.HasPrivateFields;
2010     ToData.HasProtectedFields = FromData.HasProtectedFields;
2011     ToData.HasPublicFields = FromData.HasPublicFields;
2012     ToData.HasMutableFields = FromData.HasMutableFields;
2013     ToData.HasVariantMembers = FromData.HasVariantMembers;
2014     ToData.HasOnlyCMembers = FromData.HasOnlyCMembers;
2015     ToData.HasInClassInitializer = FromData.HasInClassInitializer;
2016     ToData.HasUninitializedReferenceMember
2017       = FromData.HasUninitializedReferenceMember;
2018     ToData.NeedOverloadResolutionForMoveConstructor
2019       = FromData.NeedOverloadResolutionForMoveConstructor;
2020     ToData.NeedOverloadResolutionForMoveAssignment
2021       = FromData.NeedOverloadResolutionForMoveAssignment;
2022     ToData.NeedOverloadResolutionForDestructor
2023       = FromData.NeedOverloadResolutionForDestructor;
2024     ToData.DefaultedMoveConstructorIsDeleted
2025       = FromData.DefaultedMoveConstructorIsDeleted;
2026     ToData.DefaultedMoveAssignmentIsDeleted
2027       = FromData.DefaultedMoveAssignmentIsDeleted;
2028     ToData.DefaultedDestructorIsDeleted = FromData.DefaultedDestructorIsDeleted;
2029     ToData.HasTrivialSpecialMembers = FromData.HasTrivialSpecialMembers;
2030     ToData.HasIrrelevantDestructor = FromData.HasIrrelevantDestructor;
2031     ToData.HasConstexprNonCopyMoveConstructor
2032       = FromData.HasConstexprNonCopyMoveConstructor;
2033     ToData.DefaultedDefaultConstructorIsConstexpr
2034       = FromData.DefaultedDefaultConstructorIsConstexpr;
2035     ToData.HasConstexprDefaultConstructor
2036       = FromData.HasConstexprDefaultConstructor;
2037     ToData.HasNonLiteralTypeFieldsOrBases
2038       = FromData.HasNonLiteralTypeFieldsOrBases;
2039     // ComputedVisibleConversions not imported.
2040     ToData.UserProvidedDefaultConstructor
2041       = FromData.UserProvidedDefaultConstructor;
2042     ToData.DeclaredSpecialMembers = FromData.DeclaredSpecialMembers;
2043     ToData.ImplicitCopyConstructorHasConstParam
2044       = FromData.ImplicitCopyConstructorHasConstParam;
2045     ToData.ImplicitCopyAssignmentHasConstParam
2046       = FromData.ImplicitCopyAssignmentHasConstParam;
2047     ToData.HasDeclaredCopyConstructorWithConstParam
2048       = FromData.HasDeclaredCopyConstructorWithConstParam;
2049     ToData.HasDeclaredCopyAssignmentWithConstParam
2050       = FromData.HasDeclaredCopyAssignmentWithConstParam;
2051     ToData.IsLambda = FromData.IsLambda;
2052
2053     SmallVector<CXXBaseSpecifier *, 4> Bases;
2054     for (const auto &Base1 : FromCXX->bases()) {
2055       QualType T = Importer.Import(Base1.getType());
2056       if (T.isNull())
2057         return true;
2058
2059       SourceLocation EllipsisLoc;
2060       if (Base1.isPackExpansion())
2061         EllipsisLoc = Importer.Import(Base1.getEllipsisLoc());
2062
2063       // Ensure that we have a definition for the base.
2064       ImportDefinitionIfNeeded(Base1.getType()->getAsCXXRecordDecl());
2065
2066       Bases.push_back(
2067                     new (Importer.getToContext())
2068                       CXXBaseSpecifier(Importer.Import(Base1.getSourceRange()),
2069                                        Base1.isVirtual(),
2070                                        Base1.isBaseOfClass(),
2071                                        Base1.getAccessSpecifierAsWritten(),
2072                                    Importer.Import(Base1.getTypeSourceInfo()),
2073                                        EllipsisLoc));
2074     }
2075     if (!Bases.empty())
2076       ToCXX->setBases(Bases.data(), Bases.size());
2077   }
2078
2079   if (shouldForceImportDeclContext(Kind))
2080     ImportDeclContext(From, /*ForceImport=*/true);
2081
2082   To->completeDefinition();
2083   return false;
2084 }
2085
2086 bool ASTNodeImporter::ImportDefinition(VarDecl *From, VarDecl *To,
2087                                        ImportDefinitionKind Kind) {
2088   if (To->getAnyInitializer())
2089     return false;
2090
2091   // FIXME: Can we really import any initializer? Alternatively, we could force
2092   // ourselves to import every declaration of a variable and then only use
2093   // getInit() here.
2094   To->setInit(Importer.Import(const_cast<Expr *>(From->getAnyInitializer())));
2095
2096   // FIXME: Other bits to merge?
2097
2098   return false;
2099 }
2100
2101 bool ASTNodeImporter::ImportDefinition(EnumDecl *From, EnumDecl *To,
2102                                        ImportDefinitionKind Kind) {
2103   if (To->getDefinition() || To->isBeingDefined()) {
2104     if (Kind == IDK_Everything)
2105       ImportDeclContext(From, /*ForceImport=*/true);
2106     return false;
2107   }
2108
2109   To->startDefinition();
2110
2111   QualType T = Importer.Import(Importer.getFromContext().getTypeDeclType(From));
2112   if (T.isNull())
2113     return true;
2114
2115   QualType ToPromotionType = Importer.Import(From->getPromotionType());
2116   if (ToPromotionType.isNull())
2117     return true;
2118
2119   if (shouldForceImportDeclContext(Kind))
2120     ImportDeclContext(From, /*ForceImport=*/true);
2121
2122   // FIXME: we might need to merge the number of positive or negative bits
2123   // if the enumerator lists don't match.
2124   To->completeDefinition(T, ToPromotionType,
2125                          From->getNumPositiveBits(),
2126                          From->getNumNegativeBits());
2127   return false;
2128 }
2129
2130 TemplateParameterList *ASTNodeImporter::ImportTemplateParameterList(
2131                                                 TemplateParameterList *Params) {
2132   SmallVector<NamedDecl *, 4> ToParams;
2133   ToParams.reserve(Params->size());
2134   for (TemplateParameterList::iterator P = Params->begin(),
2135                                     PEnd = Params->end();
2136        P != PEnd; ++P) {
2137     Decl *To = Importer.Import(*P);
2138     if (!To)
2139       return nullptr;
2140
2141     ToParams.push_back(cast<NamedDecl>(To));
2142   }
2143
2144   return TemplateParameterList::Create(Importer.getToContext(),
2145                                        Importer.Import(Params->getTemplateLoc()),
2146                                        Importer.Import(Params->getLAngleLoc()),
2147                                        ToParams.data(), ToParams.size(),
2148                                        Importer.Import(Params->getRAngleLoc()));
2149 }
2150
2151 TemplateArgument
2152 ASTNodeImporter::ImportTemplateArgument(const TemplateArgument &From) {
2153   switch (From.getKind()) {
2154   case TemplateArgument::Null:
2155     return TemplateArgument();
2156
2157   case TemplateArgument::Type: {
2158     QualType ToType = Importer.Import(From.getAsType());
2159     if (ToType.isNull())
2160       return TemplateArgument();
2161     return TemplateArgument(ToType);
2162   }
2163
2164   case TemplateArgument::Integral: {
2165     QualType ToType = Importer.Import(From.getIntegralType());
2166     if (ToType.isNull())
2167       return TemplateArgument();
2168     return TemplateArgument(From, ToType);
2169   }
2170
2171   case TemplateArgument::Declaration: {
2172     ValueDecl *To = cast_or_null<ValueDecl>(Importer.Import(From.getAsDecl()));
2173     QualType ToType = Importer.Import(From.getParamTypeForDecl());
2174     if (!To || ToType.isNull())
2175       return TemplateArgument();
2176     return TemplateArgument(To, ToType);
2177   }
2178
2179   case TemplateArgument::NullPtr: {
2180     QualType ToType = Importer.Import(From.getNullPtrType());
2181     if (ToType.isNull())
2182       return TemplateArgument();
2183     return TemplateArgument(ToType, /*isNullPtr*/true);
2184   }
2185
2186   case TemplateArgument::Template: {
2187     TemplateName ToTemplate = Importer.Import(From.getAsTemplate());
2188     if (ToTemplate.isNull())
2189       return TemplateArgument();
2190
2191     return TemplateArgument(ToTemplate);
2192   }
2193
2194   case TemplateArgument::TemplateExpansion: {
2195     TemplateName ToTemplate
2196       = Importer.Import(From.getAsTemplateOrTemplatePattern());
2197     if (ToTemplate.isNull())
2198       return TemplateArgument();
2199
2200     return TemplateArgument(ToTemplate, From.getNumTemplateExpansions());
2201   }
2202
2203   case TemplateArgument::Expression:
2204     if (Expr *ToExpr = Importer.Import(From.getAsExpr()))
2205       return TemplateArgument(ToExpr);
2206     return TemplateArgument();
2207
2208   case TemplateArgument::Pack: {
2209     SmallVector<TemplateArgument, 2> ToPack;
2210     ToPack.reserve(From.pack_size());
2211     if (ImportTemplateArguments(From.pack_begin(), From.pack_size(), ToPack))
2212       return TemplateArgument();
2213
2214     TemplateArgument *ToArgs
2215       = new (Importer.getToContext()) TemplateArgument[ToPack.size()];
2216     std::copy(ToPack.begin(), ToPack.end(), ToArgs);
2217     return TemplateArgument(ToArgs, ToPack.size());
2218   }
2219   }
2220
2221   llvm_unreachable("Invalid template argument kind");
2222 }
2223
2224 bool ASTNodeImporter::ImportTemplateArguments(const TemplateArgument *FromArgs,
2225                                               unsigned NumFromArgs,
2226                               SmallVectorImpl<TemplateArgument> &ToArgs) {
2227   for (unsigned I = 0; I != NumFromArgs; ++I) {
2228     TemplateArgument To = ImportTemplateArgument(FromArgs[I]);
2229     if (To.isNull() && !FromArgs[I].isNull())
2230       return true;
2231
2232     ToArgs.push_back(To);
2233   }
2234
2235   return false;
2236 }
2237
2238 bool ASTNodeImporter::IsStructuralMatch(RecordDecl *FromRecord,
2239                                         RecordDecl *ToRecord, bool Complain) {
2240   // Eliminate a potential failure point where we attempt to re-import
2241   // something we're trying to import while completing ToRecord.
2242   Decl *ToOrigin = Importer.GetOriginalDecl(ToRecord);
2243   if (ToOrigin) {
2244     RecordDecl *ToOriginRecord = dyn_cast<RecordDecl>(ToOrigin);
2245     if (ToOriginRecord)
2246       ToRecord = ToOriginRecord;
2247   }
2248
2249   StructuralEquivalenceContext Ctx(Importer.getFromContext(),
2250                                    ToRecord->getASTContext(),
2251                                    Importer.getNonEquivalentDecls(),
2252                                    false, Complain);
2253   return Ctx.IsStructurallyEquivalent(FromRecord, ToRecord);
2254 }
2255
2256 bool ASTNodeImporter::IsStructuralMatch(VarDecl *FromVar, VarDecl *ToVar,
2257                                         bool Complain) {
2258   StructuralEquivalenceContext Ctx(
2259       Importer.getFromContext(), Importer.getToContext(),
2260       Importer.getNonEquivalentDecls(), false, Complain);
2261   return Ctx.IsStructurallyEquivalent(FromVar, ToVar);
2262 }
2263
2264 bool ASTNodeImporter::IsStructuralMatch(EnumDecl *FromEnum, EnumDecl *ToEnum) {
2265   StructuralEquivalenceContext Ctx(Importer.getFromContext(),
2266                                    Importer.getToContext(),
2267                                    Importer.getNonEquivalentDecls());
2268   return Ctx.IsStructurallyEquivalent(FromEnum, ToEnum);
2269 }
2270
2271 bool ASTNodeImporter::IsStructuralMatch(EnumConstantDecl *FromEC,
2272                                         EnumConstantDecl *ToEC)
2273 {
2274   const llvm::APSInt &FromVal = FromEC->getInitVal();
2275   const llvm::APSInt &ToVal = ToEC->getInitVal();
2276
2277   return FromVal.isSigned() == ToVal.isSigned() &&
2278          FromVal.getBitWidth() == ToVal.getBitWidth() &&
2279          FromVal == ToVal;
2280 }
2281
2282 bool ASTNodeImporter::IsStructuralMatch(ClassTemplateDecl *From,
2283                                         ClassTemplateDecl *To) {
2284   StructuralEquivalenceContext Ctx(Importer.getFromContext(),
2285                                    Importer.getToContext(),
2286                                    Importer.getNonEquivalentDecls());
2287   return Ctx.IsStructurallyEquivalent(From, To);
2288 }
2289
2290 bool ASTNodeImporter::IsStructuralMatch(VarTemplateDecl *From,
2291                                         VarTemplateDecl *To) {
2292   StructuralEquivalenceContext Ctx(Importer.getFromContext(),
2293                                    Importer.getToContext(),
2294                                    Importer.getNonEquivalentDecls());
2295   return Ctx.IsStructurallyEquivalent(From, To);
2296 }
2297
2298 Decl *ASTNodeImporter::VisitDecl(Decl *D) {
2299   Importer.FromDiag(D->getLocation(), diag::err_unsupported_ast_node)
2300     << D->getDeclKindName();
2301   return nullptr;
2302 }
2303
2304 Decl *ASTNodeImporter::VisitTranslationUnitDecl(TranslationUnitDecl *D) {
2305   TranslationUnitDecl *ToD =
2306     Importer.getToContext().getTranslationUnitDecl();
2307
2308   Importer.Imported(D, ToD);
2309
2310   return ToD;
2311 }
2312
2313 Decl *ASTNodeImporter::VisitNamespaceDecl(NamespaceDecl *D) {
2314   // Import the major distinguishing characteristics of this namespace.
2315   DeclContext *DC, *LexicalDC;
2316   DeclarationName Name;
2317   SourceLocation Loc;
2318   NamedDecl *ToD;
2319   if (ImportDeclParts(D, DC, LexicalDC, Name, ToD, Loc))
2320     return nullptr;
2321   if (ToD)
2322     return ToD;
2323
2324   NamespaceDecl *MergeWithNamespace = nullptr;
2325   if (!Name) {
2326     // This is an anonymous namespace. Adopt an existing anonymous
2327     // namespace if we can.
2328     // FIXME: Not testable.
2329     if (TranslationUnitDecl *TU = dyn_cast<TranslationUnitDecl>(DC))
2330       MergeWithNamespace = TU->getAnonymousNamespace();
2331     else
2332       MergeWithNamespace = cast<NamespaceDecl>(DC)->getAnonymousNamespace();
2333   } else {
2334     SmallVector<NamedDecl *, 4> ConflictingDecls;
2335     SmallVector<NamedDecl *, 2> FoundDecls;
2336     DC->getRedeclContext()->localUncachedLookup(Name, FoundDecls);
2337     for (unsigned I = 0, N = FoundDecls.size(); I != N; ++I) {
2338       if (!FoundDecls[I]->isInIdentifierNamespace(Decl::IDNS_Namespace))
2339         continue;
2340
2341       if (NamespaceDecl *FoundNS = dyn_cast<NamespaceDecl>(FoundDecls[I])) {
2342         MergeWithNamespace = FoundNS;
2343         ConflictingDecls.clear();
2344         break;
2345       }
2346
2347       ConflictingDecls.push_back(FoundDecls[I]);
2348     }
2349
2350     if (!ConflictingDecls.empty()) {
2351       Name = Importer.HandleNameConflict(Name, DC, Decl::IDNS_Namespace,
2352                                          ConflictingDecls.data(),
2353                                          ConflictingDecls.size());
2354     }
2355   }
2356
2357   // Create the "to" namespace, if needed.
2358   NamespaceDecl *ToNamespace = MergeWithNamespace;
2359   if (!ToNamespace) {
2360     ToNamespace = NamespaceDecl::Create(Importer.getToContext(), DC,
2361                                         D->isInline(),
2362                                         Importer.Import(D->getLocStart()),
2363                                         Loc, Name.getAsIdentifierInfo(),
2364                                         /*PrevDecl=*/nullptr);
2365     ToNamespace->setLexicalDeclContext(LexicalDC);
2366     LexicalDC->addDeclInternal(ToNamespace);
2367
2368     // If this is an anonymous namespace, register it as the anonymous
2369     // namespace within its context.
2370     if (!Name) {
2371       if (TranslationUnitDecl *TU = dyn_cast<TranslationUnitDecl>(DC))
2372         TU->setAnonymousNamespace(ToNamespace);
2373       else
2374         cast<NamespaceDecl>(DC)->setAnonymousNamespace(ToNamespace);
2375     }
2376   }
2377   Importer.Imported(D, ToNamespace);
2378
2379   ImportDeclContext(D);
2380
2381   return ToNamespace;
2382 }
2383
2384 Decl *ASTNodeImporter::VisitTypedefNameDecl(TypedefNameDecl *D, bool IsAlias) {
2385   // Import the major distinguishing characteristics of this typedef.
2386   DeclContext *DC, *LexicalDC;
2387   DeclarationName Name;
2388   SourceLocation Loc;
2389   NamedDecl *ToD;
2390   if (ImportDeclParts(D, DC, LexicalDC, Name, ToD, Loc))
2391     return nullptr;
2392   if (ToD)
2393     return ToD;
2394
2395   // If this typedef is not in block scope, determine whether we've
2396   // seen a typedef with the same name (that we can merge with) or any
2397   // other entity by that name (which name lookup could conflict with).
2398   if (!DC->isFunctionOrMethod()) {
2399     SmallVector<NamedDecl *, 4> ConflictingDecls;
2400     unsigned IDNS = Decl::IDNS_Ordinary;
2401     SmallVector<NamedDecl *, 2> FoundDecls;
2402     DC->getRedeclContext()->localUncachedLookup(Name, FoundDecls);
2403     for (unsigned I = 0, N = FoundDecls.size(); I != N; ++I) {
2404       if (!FoundDecls[I]->isInIdentifierNamespace(IDNS))
2405         continue;
2406       if (TypedefNameDecl *FoundTypedef =
2407             dyn_cast<TypedefNameDecl>(FoundDecls[I])) {
2408         if (Importer.IsStructurallyEquivalent(D->getUnderlyingType(),
2409                                             FoundTypedef->getUnderlyingType()))
2410           return Importer.Imported(D, FoundTypedef);
2411       }
2412
2413       ConflictingDecls.push_back(FoundDecls[I]);
2414     }
2415
2416     if (!ConflictingDecls.empty()) {
2417       Name = Importer.HandleNameConflict(Name, DC, IDNS,
2418                                          ConflictingDecls.data(),
2419                                          ConflictingDecls.size());
2420       if (!Name)
2421         return nullptr;
2422     }
2423   }
2424
2425   // Import the underlying type of this typedef;
2426   QualType T = Importer.Import(D->getUnderlyingType());
2427   if (T.isNull())
2428     return nullptr;
2429
2430   // Create the new typedef node.
2431   TypeSourceInfo *TInfo = Importer.Import(D->getTypeSourceInfo());
2432   SourceLocation StartL = Importer.Import(D->getLocStart());
2433   TypedefNameDecl *ToTypedef;
2434   if (IsAlias)
2435     ToTypedef = TypeAliasDecl::Create(Importer.getToContext(), DC,
2436                                       StartL, Loc,
2437                                       Name.getAsIdentifierInfo(),
2438                                       TInfo);
2439   else
2440     ToTypedef = TypedefDecl::Create(Importer.getToContext(), DC,
2441                                     StartL, Loc,
2442                                     Name.getAsIdentifierInfo(),
2443                                     TInfo);
2444
2445   ToTypedef->setAccess(D->getAccess());
2446   ToTypedef->setLexicalDeclContext(LexicalDC);
2447   Importer.Imported(D, ToTypedef);
2448   LexicalDC->addDeclInternal(ToTypedef);
2449
2450   return ToTypedef;
2451 }
2452
2453 Decl *ASTNodeImporter::VisitTypedefDecl(TypedefDecl *D) {
2454   return VisitTypedefNameDecl(D, /*IsAlias=*/false);
2455 }
2456
2457 Decl *ASTNodeImporter::VisitTypeAliasDecl(TypeAliasDecl *D) {
2458   return VisitTypedefNameDecl(D, /*IsAlias=*/true);
2459 }
2460
2461 Decl *ASTNodeImporter::VisitEnumDecl(EnumDecl *D) {
2462   // Import the major distinguishing characteristics of this enum.
2463   DeclContext *DC, *LexicalDC;
2464   DeclarationName Name;
2465   SourceLocation Loc;
2466   NamedDecl *ToD;
2467   if (ImportDeclParts(D, DC, LexicalDC, Name, ToD, Loc))
2468     return nullptr;
2469   if (ToD)
2470     return ToD;
2471
2472   // Figure out what enum name we're looking for.
2473   unsigned IDNS = Decl::IDNS_Tag;
2474   DeclarationName SearchName = Name;
2475   if (!SearchName && D->getTypedefNameForAnonDecl()) {
2476     SearchName = Importer.Import(D->getTypedefNameForAnonDecl()->getDeclName());
2477     IDNS = Decl::IDNS_Ordinary;
2478   } else if (Importer.getToContext().getLangOpts().CPlusPlus)
2479     IDNS |= Decl::IDNS_Ordinary;
2480
2481   // We may already have an enum of the same name; try to find and match it.
2482   if (!DC->isFunctionOrMethod() && SearchName) {
2483     SmallVector<NamedDecl *, 4> ConflictingDecls;
2484     SmallVector<NamedDecl *, 2> FoundDecls;
2485     DC->getRedeclContext()->localUncachedLookup(Name, 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 (EnumDecl *FoundEnum = dyn_cast<EnumDecl>(Found)) {
2497         if (IsStructuralMatch(D, FoundEnum))
2498           return Importer.Imported(D, FoundEnum);
2499       }
2500
2501       ConflictingDecls.push_back(FoundDecls[I]);
2502     }
2503
2504     if (!ConflictingDecls.empty()) {
2505       Name = Importer.HandleNameConflict(Name, DC, IDNS,
2506                                          ConflictingDecls.data(),
2507                                          ConflictingDecls.size());
2508     }
2509   }
2510
2511   // Create the enum declaration.
2512   EnumDecl *D2 = EnumDecl::Create(Importer.getToContext(), DC,
2513                                   Importer.Import(D->getLocStart()),
2514                                   Loc, Name.getAsIdentifierInfo(), nullptr,
2515                                   D->isScoped(), D->isScopedUsingClassTag(),
2516                                   D->isFixed());
2517   // Import the qualifier, if any.
2518   D2->setQualifierInfo(Importer.Import(D->getQualifierLoc()));
2519   D2->setAccess(D->getAccess());
2520   D2->setLexicalDeclContext(LexicalDC);
2521   Importer.Imported(D, D2);
2522   LexicalDC->addDeclInternal(D2);
2523
2524   // Import the integer type.
2525   QualType ToIntegerType = Importer.Import(D->getIntegerType());
2526   if (ToIntegerType.isNull())
2527     return nullptr;
2528   D2->setIntegerType(ToIntegerType);
2529
2530   // Import the definition
2531   if (D->isCompleteDefinition() && ImportDefinition(D, D2))
2532     return nullptr;
2533
2534   return D2;
2535 }
2536
2537 Decl *ASTNodeImporter::VisitRecordDecl(RecordDecl *D) {
2538   // If this record has a definition in the translation unit we're coming from,
2539   // but this particular declaration is not that definition, import the
2540   // definition and map to that.
2541   TagDecl *Definition = D->getDefinition();
2542   if (Definition && Definition != D) {
2543     Decl *ImportedDef = Importer.Import(Definition);
2544     if (!ImportedDef)
2545       return nullptr;
2546
2547     return Importer.Imported(D, ImportedDef);
2548   }
2549
2550   // Import the major distinguishing characteristics of this record.
2551   DeclContext *DC, *LexicalDC;
2552   DeclarationName Name;
2553   SourceLocation Loc;
2554   NamedDecl *ToD;
2555   if (ImportDeclParts(D, DC, LexicalDC, Name, ToD, Loc))
2556     return nullptr;
2557   if (ToD)
2558     return ToD;
2559
2560   // Figure out what structure name we're looking for.
2561   unsigned IDNS = Decl::IDNS_Tag;
2562   DeclarationName SearchName = Name;
2563   if (!SearchName && D->getTypedefNameForAnonDecl()) {
2564     SearchName = Importer.Import(D->getTypedefNameForAnonDecl()->getDeclName());
2565     IDNS = Decl::IDNS_Ordinary;
2566   } else if (Importer.getToContext().getLangOpts().CPlusPlus)
2567     IDNS |= Decl::IDNS_Ordinary;
2568
2569   // We may already have a record of the same name; try to find and match it.
2570   RecordDecl *AdoptDecl = nullptr;
2571   if (!DC->isFunctionOrMethod()) {
2572     SmallVector<NamedDecl *, 4> ConflictingDecls;
2573     SmallVector<NamedDecl *, 2> FoundDecls;
2574     DC->getRedeclContext()->localUncachedLookup(Name, FoundDecls);
2575     for (unsigned I = 0, N = FoundDecls.size(); I != N; ++I) {
2576       if (!FoundDecls[I]->isInIdentifierNamespace(IDNS))
2577         continue;
2578
2579       Decl *Found = FoundDecls[I];
2580       if (TypedefNameDecl *Typedef = dyn_cast<TypedefNameDecl>(Found)) {
2581         if (const TagType *Tag = Typedef->getUnderlyingType()->getAs<TagType>())
2582           Found = Tag->getDecl();
2583       }
2584
2585       if (RecordDecl *FoundRecord = dyn_cast<RecordDecl>(Found)) {
2586         if (D->isAnonymousStructOrUnion() &&
2587             FoundRecord->isAnonymousStructOrUnion()) {
2588           // If both anonymous structs/unions are in a record context, make sure
2589           // they occur in the same location in the context records.
2590           if (Optional<unsigned> Index1
2591               = findAnonymousStructOrUnionIndex(D)) {
2592             if (Optional<unsigned> Index2 =
2593                     findAnonymousStructOrUnionIndex(FoundRecord)) {
2594               if (*Index1 != *Index2)
2595                 continue;
2596             }
2597           }
2598         }
2599
2600         if (RecordDecl *FoundDef = FoundRecord->getDefinition()) {
2601           if ((SearchName && !D->isCompleteDefinition())
2602               || (D->isCompleteDefinition() &&
2603                   D->isAnonymousStructOrUnion()
2604                     == FoundDef->isAnonymousStructOrUnion() &&
2605                   IsStructuralMatch(D, FoundDef))) {
2606             // The record types structurally match, or the "from" translation
2607             // unit only had a forward declaration anyway; call it the same
2608             // function.
2609             // FIXME: For C++, we should also merge methods here.
2610             return Importer.Imported(D, FoundDef);
2611           }
2612         } else if (!D->isCompleteDefinition()) {
2613           // We have a forward declaration of this type, so adopt that forward
2614           // declaration rather than building a new one.
2615
2616           // If one or both can be completed from external storage then try one
2617           // last time to complete and compare them before doing this.
2618
2619           if (FoundRecord->hasExternalLexicalStorage() &&
2620               !FoundRecord->isCompleteDefinition())
2621             FoundRecord->getASTContext().getExternalSource()->CompleteType(FoundRecord);
2622           if (D->hasExternalLexicalStorage())
2623             D->getASTContext().getExternalSource()->CompleteType(D);
2624
2625           if (FoundRecord->isCompleteDefinition() &&
2626               D->isCompleteDefinition() &&
2627               !IsStructuralMatch(D, FoundRecord))
2628             continue;
2629
2630           AdoptDecl = FoundRecord;
2631           continue;
2632         } else if (!SearchName) {
2633           continue;
2634         }
2635       }
2636
2637       ConflictingDecls.push_back(FoundDecls[I]);
2638     }
2639
2640     if (!ConflictingDecls.empty() && SearchName) {
2641       Name = Importer.HandleNameConflict(Name, DC, IDNS,
2642                                          ConflictingDecls.data(),
2643                                          ConflictingDecls.size());
2644     }
2645   }
2646
2647   // Create the record declaration.
2648   RecordDecl *D2 = AdoptDecl;
2649   SourceLocation StartLoc = Importer.Import(D->getLocStart());
2650   if (!D2) {
2651     if (isa<CXXRecordDecl>(D)) {
2652       CXXRecordDecl *D2CXX = CXXRecordDecl::Create(Importer.getToContext(),
2653                                                    D->getTagKind(),
2654                                                    DC, StartLoc, Loc,
2655                                                    Name.getAsIdentifierInfo());
2656       D2 = D2CXX;
2657       D2->setAccess(D->getAccess());
2658     } else {
2659       D2 = RecordDecl::Create(Importer.getToContext(), D->getTagKind(),
2660                               DC, StartLoc, Loc, Name.getAsIdentifierInfo());
2661     }
2662
2663     D2->setQualifierInfo(Importer.Import(D->getQualifierLoc()));
2664     D2->setLexicalDeclContext(LexicalDC);
2665     LexicalDC->addDeclInternal(D2);
2666     if (D->isAnonymousStructOrUnion())
2667       D2->setAnonymousStructOrUnion(true);
2668   }
2669
2670   Importer.Imported(D, D2);
2671
2672   if (D->isCompleteDefinition() && ImportDefinition(D, D2, IDK_Default))
2673     return nullptr;
2674
2675   return D2;
2676 }
2677
2678 Decl *ASTNodeImporter::VisitEnumConstantDecl(EnumConstantDecl *D) {
2679   // Import the major distinguishing characteristics of this enumerator.
2680   DeclContext *DC, *LexicalDC;
2681   DeclarationName Name;
2682   SourceLocation Loc;
2683   NamedDecl *ToD;
2684   if (ImportDeclParts(D, DC, LexicalDC, Name, ToD, Loc))
2685     return nullptr;
2686   if (ToD)
2687     return ToD;
2688
2689   QualType T = Importer.Import(D->getType());
2690   if (T.isNull())
2691     return nullptr;
2692
2693   // Determine whether there are any other declarations with the same name and
2694   // in the same context.
2695   if (!LexicalDC->isFunctionOrMethod()) {
2696     SmallVector<NamedDecl *, 4> ConflictingDecls;
2697     unsigned IDNS = Decl::IDNS_Ordinary;
2698     SmallVector<NamedDecl *, 2> FoundDecls;
2699     DC->getRedeclContext()->localUncachedLookup(Name, FoundDecls);
2700     for (unsigned I = 0, N = FoundDecls.size(); I != N; ++I) {
2701       if (!FoundDecls[I]->isInIdentifierNamespace(IDNS))
2702         continue;
2703
2704       if (EnumConstantDecl *FoundEnumConstant
2705             = dyn_cast<EnumConstantDecl>(FoundDecls[I])) {
2706         if (IsStructuralMatch(D, FoundEnumConstant))
2707           return Importer.Imported(D, FoundEnumConstant);
2708       }
2709
2710       ConflictingDecls.push_back(FoundDecls[I]);
2711     }
2712
2713     if (!ConflictingDecls.empty()) {
2714       Name = Importer.HandleNameConflict(Name, DC, IDNS,
2715                                          ConflictingDecls.data(),
2716                                          ConflictingDecls.size());
2717       if (!Name)
2718         return nullptr;
2719     }
2720   }
2721
2722   Expr *Init = Importer.Import(D->getInitExpr());
2723   if (D->getInitExpr() && !Init)
2724     return nullptr;
2725
2726   EnumConstantDecl *ToEnumerator
2727     = EnumConstantDecl::Create(Importer.getToContext(), cast<EnumDecl>(DC), Loc,
2728                                Name.getAsIdentifierInfo(), T,
2729                                Init, D->getInitVal());
2730   ToEnumerator->setAccess(D->getAccess());
2731   ToEnumerator->setLexicalDeclContext(LexicalDC);
2732   Importer.Imported(D, ToEnumerator);
2733   LexicalDC->addDeclInternal(ToEnumerator);
2734   return ToEnumerator;
2735 }
2736
2737 Decl *ASTNodeImporter::VisitFunctionDecl(FunctionDecl *D) {
2738   // Import the major distinguishing characteristics of this function.
2739   DeclContext *DC, *LexicalDC;
2740   DeclarationName Name;
2741   SourceLocation Loc;
2742   NamedDecl *ToD;
2743   if (ImportDeclParts(D, DC, LexicalDC, Name, ToD, Loc))
2744     return nullptr;
2745   if (ToD)
2746     return ToD;
2747
2748   // Try to find a function in our own ("to") context with the same name, same
2749   // type, and in the same context as the function we're importing.
2750   if (!LexicalDC->isFunctionOrMethod()) {
2751     SmallVector<NamedDecl *, 4> ConflictingDecls;
2752     unsigned IDNS = Decl::IDNS_Ordinary;
2753     SmallVector<NamedDecl *, 2> FoundDecls;
2754     DC->getRedeclContext()->localUncachedLookup(Name, FoundDecls);
2755     for (unsigned I = 0, N = FoundDecls.size(); I != N; ++I) {
2756       if (!FoundDecls[I]->isInIdentifierNamespace(IDNS))
2757         continue;
2758
2759       if (FunctionDecl *FoundFunction = dyn_cast<FunctionDecl>(FoundDecls[I])) {
2760         if (FoundFunction->hasExternalFormalLinkage() &&
2761             D->hasExternalFormalLinkage()) {
2762           if (Importer.IsStructurallyEquivalent(D->getType(),
2763                                                 FoundFunction->getType())) {
2764             // FIXME: Actually try to merge the body and other attributes.
2765             return Importer.Imported(D, FoundFunction);
2766           }
2767
2768           // FIXME: Check for overloading more carefully, e.g., by boosting
2769           // Sema::IsOverload out to the AST library.
2770
2771           // Function overloading is okay in C++.
2772           if (Importer.getToContext().getLangOpts().CPlusPlus)
2773             continue;
2774
2775           // Complain about inconsistent function types.
2776           Importer.ToDiag(Loc, diag::err_odr_function_type_inconsistent)
2777             << Name << D->getType() << FoundFunction->getType();
2778           Importer.ToDiag(FoundFunction->getLocation(),
2779                           diag::note_odr_value_here)
2780             << FoundFunction->getType();
2781         }
2782       }
2783
2784       ConflictingDecls.push_back(FoundDecls[I]);
2785     }
2786
2787     if (!ConflictingDecls.empty()) {
2788       Name = Importer.HandleNameConflict(Name, DC, IDNS,
2789                                          ConflictingDecls.data(),
2790                                          ConflictingDecls.size());
2791       if (!Name)
2792         return nullptr;
2793     }
2794   }
2795
2796   DeclarationNameInfo NameInfo(Name, Loc);
2797   // Import additional name location/type info.
2798   ImportDeclarationNameLoc(D->getNameInfo(), NameInfo);
2799
2800   QualType FromTy = D->getType();
2801   bool usedDifferentExceptionSpec = false;
2802
2803   if (const FunctionProtoType *
2804         FromFPT = D->getType()->getAs<FunctionProtoType>()) {
2805     FunctionProtoType::ExtProtoInfo FromEPI = FromFPT->getExtProtoInfo();
2806     // FunctionProtoType::ExtProtoInfo's ExceptionSpecDecl can point to the
2807     // FunctionDecl that we are importing the FunctionProtoType for.
2808     // To avoid an infinite recursion when importing, create the FunctionDecl
2809     // with a simplified function type and update it afterwards.
2810     if (FromEPI.ExceptionSpec.SourceDecl ||
2811         FromEPI.ExceptionSpec.SourceTemplate ||
2812         FromEPI.ExceptionSpec.NoexceptExpr) {
2813       FunctionProtoType::ExtProtoInfo DefaultEPI;
2814       FromTy = Importer.getFromContext().getFunctionType(
2815           FromFPT->getReturnType(), FromFPT->getParamTypes(), DefaultEPI);
2816       usedDifferentExceptionSpec = true;
2817     }
2818   }
2819
2820   // Import the type.
2821   QualType T = Importer.Import(FromTy);
2822   if (T.isNull())
2823     return nullptr;
2824
2825   // Import the function parameters.
2826   SmallVector<ParmVarDecl *, 8> Parameters;
2827   for (auto P : D->params()) {
2828     ParmVarDecl *ToP = cast_or_null<ParmVarDecl>(Importer.Import(P));
2829     if (!ToP)
2830       return nullptr;
2831
2832     Parameters.push_back(ToP);
2833   }
2834
2835   // Create the imported function.
2836   TypeSourceInfo *TInfo = Importer.Import(D->getTypeSourceInfo());
2837   FunctionDecl *ToFunction = nullptr;
2838   SourceLocation InnerLocStart = Importer.Import(D->getInnerLocStart());
2839   if (CXXConstructorDecl *FromConstructor = dyn_cast<CXXConstructorDecl>(D)) {
2840     ToFunction = CXXConstructorDecl::Create(Importer.getToContext(),
2841                                             cast<CXXRecordDecl>(DC),
2842                                             InnerLocStart,
2843                                             NameInfo, T, TInfo,
2844                                             FromConstructor->isExplicit(),
2845                                             D->isInlineSpecified(),
2846                                             D->isImplicit(),
2847                                             D->isConstexpr());
2848   } else if (isa<CXXDestructorDecl>(D)) {
2849     ToFunction = CXXDestructorDecl::Create(Importer.getToContext(),
2850                                            cast<CXXRecordDecl>(DC),
2851                                            InnerLocStart,
2852                                            NameInfo, T, TInfo,
2853                                            D->isInlineSpecified(),
2854                                            D->isImplicit());
2855   } else if (CXXConversionDecl *FromConversion
2856                                            = dyn_cast<CXXConversionDecl>(D)) {
2857     ToFunction = CXXConversionDecl::Create(Importer.getToContext(),
2858                                            cast<CXXRecordDecl>(DC),
2859                                            InnerLocStart,
2860                                            NameInfo, T, TInfo,
2861                                            D->isInlineSpecified(),
2862                                            FromConversion->isExplicit(),
2863                                            D->isConstexpr(),
2864                                            Importer.Import(D->getLocEnd()));
2865   } else if (CXXMethodDecl *Method = dyn_cast<CXXMethodDecl>(D)) {
2866     ToFunction = CXXMethodDecl::Create(Importer.getToContext(),
2867                                        cast<CXXRecordDecl>(DC),
2868                                        InnerLocStart,
2869                                        NameInfo, T, TInfo,
2870                                        Method->getStorageClass(),
2871                                        Method->isInlineSpecified(),
2872                                        D->isConstexpr(),
2873                                        Importer.Import(D->getLocEnd()));
2874   } else {
2875     ToFunction = FunctionDecl::Create(Importer.getToContext(), DC,
2876                                       InnerLocStart,
2877                                       NameInfo, T, TInfo, D->getStorageClass(),
2878                                       D->isInlineSpecified(),
2879                                       D->hasWrittenPrototype(),
2880                                       D->isConstexpr());
2881   }
2882
2883   // Import the qualifier, if any.
2884   ToFunction->setQualifierInfo(Importer.Import(D->getQualifierLoc()));
2885   ToFunction->setAccess(D->getAccess());
2886   ToFunction->setLexicalDeclContext(LexicalDC);
2887   ToFunction->setVirtualAsWritten(D->isVirtualAsWritten());
2888   ToFunction->setTrivial(D->isTrivial());
2889   ToFunction->setPure(D->isPure());
2890   Importer.Imported(D, ToFunction);
2891
2892   // Set the parameters.
2893   for (unsigned I = 0, N = Parameters.size(); I != N; ++I) {
2894     Parameters[I]->setOwningFunction(ToFunction);
2895     ToFunction->addDeclInternal(Parameters[I]);
2896   }
2897   ToFunction->setParams(Parameters);
2898
2899   if (usedDifferentExceptionSpec) {
2900     // Update FunctionProtoType::ExtProtoInfo.
2901     QualType T = Importer.Import(D->getType());
2902     if (T.isNull())
2903       return nullptr;
2904     ToFunction->setType(T);
2905   }
2906
2907   // Import the body, if any.
2908   if (Stmt *FromBody = D->getBody()) {
2909     if (Stmt *ToBody = Importer.Import(FromBody)) {
2910       ToFunction->setBody(ToBody);
2911     }
2912   }
2913
2914   // FIXME: Other bits to merge?
2915
2916   // Add this function to the lexical context.
2917   LexicalDC->addDeclInternal(ToFunction);
2918
2919   return ToFunction;
2920 }
2921
2922 Decl *ASTNodeImporter::VisitCXXMethodDecl(CXXMethodDecl *D) {
2923   return VisitFunctionDecl(D);
2924 }
2925
2926 Decl *ASTNodeImporter::VisitCXXConstructorDecl(CXXConstructorDecl *D) {
2927   return VisitCXXMethodDecl(D);
2928 }
2929
2930 Decl *ASTNodeImporter::VisitCXXDestructorDecl(CXXDestructorDecl *D) {
2931   return VisitCXXMethodDecl(D);
2932 }
2933
2934 Decl *ASTNodeImporter::VisitCXXConversionDecl(CXXConversionDecl *D) {
2935   return VisitCXXMethodDecl(D);
2936 }
2937
2938 static unsigned getFieldIndex(Decl *F) {
2939   RecordDecl *Owner = dyn_cast<RecordDecl>(F->getDeclContext());
2940   if (!Owner)
2941     return 0;
2942
2943   unsigned Index = 1;
2944   for (const auto *D : Owner->noload_decls()) {
2945     if (D == F)
2946       return Index;
2947
2948     if (isa<FieldDecl>(*D) || isa<IndirectFieldDecl>(*D))
2949       ++Index;
2950   }
2951
2952   return Index;
2953 }
2954
2955 Decl *ASTNodeImporter::VisitFieldDecl(FieldDecl *D) {
2956   // Import the major distinguishing characteristics of a variable.
2957   DeclContext *DC, *LexicalDC;
2958   DeclarationName Name;
2959   SourceLocation Loc;
2960   NamedDecl *ToD;
2961   if (ImportDeclParts(D, DC, LexicalDC, Name, ToD, Loc))
2962     return nullptr;
2963   if (ToD)
2964     return ToD;
2965
2966   // Determine whether we've already imported this field.
2967   SmallVector<NamedDecl *, 2> FoundDecls;
2968   DC->getRedeclContext()->localUncachedLookup(Name, FoundDecls);
2969   for (unsigned I = 0, N = FoundDecls.size(); I != N; ++I) {
2970     if (FieldDecl *FoundField = dyn_cast<FieldDecl>(FoundDecls[I])) {
2971       // For anonymous fields, match up by index.
2972       if (!Name && getFieldIndex(D) != getFieldIndex(FoundField))
2973         continue;
2974
2975       if (Importer.IsStructurallyEquivalent(D->getType(),
2976                                             FoundField->getType())) {
2977         Importer.Imported(D, FoundField);
2978         return FoundField;
2979       }
2980
2981       Importer.ToDiag(Loc, diag::err_odr_field_type_inconsistent)
2982         << Name << D->getType() << FoundField->getType();
2983       Importer.ToDiag(FoundField->getLocation(), diag::note_odr_value_here)
2984         << FoundField->getType();
2985       return nullptr;
2986     }
2987   }
2988
2989   // Import the type.
2990   QualType T = Importer.Import(D->getType());
2991   if (T.isNull())
2992     return nullptr;
2993
2994   TypeSourceInfo *TInfo = Importer.Import(D->getTypeSourceInfo());
2995   Expr *BitWidth = Importer.Import(D->getBitWidth());
2996   if (!BitWidth && D->getBitWidth())
2997     return nullptr;
2998
2999   FieldDecl *ToField = FieldDecl::Create(Importer.getToContext(), DC,
3000                                          Importer.Import(D->getInnerLocStart()),
3001                                          Loc, Name.getAsIdentifierInfo(),
3002                                          T, TInfo, BitWidth, D->isMutable(),
3003                                          D->getInClassInitStyle());
3004   ToField->setAccess(D->getAccess());
3005   ToField->setLexicalDeclContext(LexicalDC);
3006   if (ToField->hasInClassInitializer())
3007     ToField->setInClassInitializer(D->getInClassInitializer());
3008   ToField->setImplicit(D->isImplicit());
3009   Importer.Imported(D, ToField);
3010   LexicalDC->addDeclInternal(ToField);
3011   return ToField;
3012 }
3013
3014 Decl *ASTNodeImporter::VisitIndirectFieldDecl(IndirectFieldDecl *D) {
3015   // Import the major distinguishing characteristics of a variable.
3016   DeclContext *DC, *LexicalDC;
3017   DeclarationName Name;
3018   SourceLocation Loc;
3019   NamedDecl *ToD;
3020   if (ImportDeclParts(D, DC, LexicalDC, Name, ToD, Loc))
3021     return nullptr;
3022   if (ToD)
3023     return ToD;
3024
3025   // Determine whether we've already imported this field.
3026   SmallVector<NamedDecl *, 2> FoundDecls;
3027   DC->getRedeclContext()->localUncachedLookup(Name, FoundDecls);
3028   for (unsigned I = 0, N = FoundDecls.size(); I != N; ++I) {
3029     if (IndirectFieldDecl *FoundField
3030                                 = dyn_cast<IndirectFieldDecl>(FoundDecls[I])) {
3031       // For anonymous indirect fields, match up by index.
3032       if (!Name && getFieldIndex(D) != getFieldIndex(FoundField))
3033         continue;
3034
3035       if (Importer.IsStructurallyEquivalent(D->getType(),
3036                                             FoundField->getType(),
3037                                             !Name.isEmpty())) {
3038         Importer.Imported(D, FoundField);
3039         return FoundField;
3040       }
3041
3042       // If there are more anonymous fields to check, continue.
3043       if (!Name && I < N-1)
3044         continue;
3045
3046       Importer.ToDiag(Loc, diag::err_odr_field_type_inconsistent)
3047         << Name << D->getType() << FoundField->getType();
3048       Importer.ToDiag(FoundField->getLocation(), diag::note_odr_value_here)
3049         << FoundField->getType();
3050       return nullptr;
3051     }
3052   }
3053
3054   // Import the type.
3055   QualType T = Importer.Import(D->getType());
3056   if (T.isNull())
3057     return nullptr;
3058
3059   NamedDecl **NamedChain =
3060     new (Importer.getToContext())NamedDecl*[D->getChainingSize()];
3061
3062   unsigned i = 0;
3063   for (auto *PI : D->chain()) {
3064     Decl *D = Importer.Import(PI);
3065     if (!D)
3066       return nullptr;
3067     NamedChain[i++] = cast<NamedDecl>(D);
3068   }
3069
3070   IndirectFieldDecl *ToIndirectField = IndirectFieldDecl::Create(
3071       Importer.getToContext(), DC, Loc, Name.getAsIdentifierInfo(), T,
3072       NamedChain, D->getChainingSize());
3073
3074   for (const auto *Attr : D->attrs())
3075     ToIndirectField->addAttr(Attr->clone(Importer.getToContext()));
3076
3077   ToIndirectField->setAccess(D->getAccess());
3078   ToIndirectField->setLexicalDeclContext(LexicalDC);
3079   Importer.Imported(D, ToIndirectField);
3080   LexicalDC->addDeclInternal(ToIndirectField);
3081   return ToIndirectField;
3082 }
3083
3084 Decl *ASTNodeImporter::VisitObjCIvarDecl(ObjCIvarDecl *D) {
3085   // Import the major distinguishing characteristics of an ivar.
3086   DeclContext *DC, *LexicalDC;
3087   DeclarationName Name;
3088   SourceLocation Loc;
3089   NamedDecl *ToD;
3090   if (ImportDeclParts(D, DC, LexicalDC, Name, ToD, Loc))
3091     return nullptr;
3092   if (ToD)
3093     return ToD;
3094
3095   // Determine whether we've already imported this ivar
3096   SmallVector<NamedDecl *, 2> FoundDecls;
3097   DC->getRedeclContext()->localUncachedLookup(Name, FoundDecls);
3098   for (unsigned I = 0, N = FoundDecls.size(); I != N; ++I) {
3099     if (ObjCIvarDecl *FoundIvar = dyn_cast<ObjCIvarDecl>(FoundDecls[I])) {
3100       if (Importer.IsStructurallyEquivalent(D->getType(),
3101                                             FoundIvar->getType())) {
3102         Importer.Imported(D, FoundIvar);
3103         return FoundIvar;
3104       }
3105
3106       Importer.ToDiag(Loc, diag::err_odr_ivar_type_inconsistent)
3107         << Name << D->getType() << FoundIvar->getType();
3108       Importer.ToDiag(FoundIvar->getLocation(), diag::note_odr_value_here)
3109         << FoundIvar->getType();
3110       return nullptr;
3111     }
3112   }
3113
3114   // Import the type.
3115   QualType T = Importer.Import(D->getType());
3116   if (T.isNull())
3117     return nullptr;
3118
3119   TypeSourceInfo *TInfo = Importer.Import(D->getTypeSourceInfo());
3120   Expr *BitWidth = Importer.Import(D->getBitWidth());
3121   if (!BitWidth && D->getBitWidth())
3122     return nullptr;
3123
3124   ObjCIvarDecl *ToIvar = ObjCIvarDecl::Create(Importer.getToContext(),
3125                                               cast<ObjCContainerDecl>(DC),
3126                                        Importer.Import(D->getInnerLocStart()),
3127                                               Loc, Name.getAsIdentifierInfo(),
3128                                               T, TInfo, D->getAccessControl(),
3129                                               BitWidth, D->getSynthesize());
3130   ToIvar->setLexicalDeclContext(LexicalDC);
3131   Importer.Imported(D, ToIvar);
3132   LexicalDC->addDeclInternal(ToIvar);
3133   return ToIvar;
3134
3135 }
3136
3137 Decl *ASTNodeImporter::VisitVarDecl(VarDecl *D) {
3138   // Import the major distinguishing characteristics of a variable.
3139   DeclContext *DC, *LexicalDC;
3140   DeclarationName Name;
3141   SourceLocation Loc;
3142   NamedDecl *ToD;
3143   if (ImportDeclParts(D, DC, LexicalDC, Name, ToD, Loc))
3144     return nullptr;
3145   if (ToD)
3146     return ToD;
3147
3148   // Try to find a variable in our own ("to") context with the same name and
3149   // in the same context as the variable we're importing.
3150   if (D->isFileVarDecl()) {
3151     VarDecl *MergeWithVar = nullptr;
3152     SmallVector<NamedDecl *, 4> ConflictingDecls;
3153     unsigned IDNS = Decl::IDNS_Ordinary;
3154     SmallVector<NamedDecl *, 2> FoundDecls;
3155     DC->getRedeclContext()->localUncachedLookup(Name, FoundDecls);
3156     for (unsigned I = 0, N = FoundDecls.size(); I != N; ++I) {
3157       if (!FoundDecls[I]->isInIdentifierNamespace(IDNS))
3158         continue;
3159
3160       if (VarDecl *FoundVar = dyn_cast<VarDecl>(FoundDecls[I])) {
3161         // We have found a variable that we may need to merge with. Check it.
3162         if (FoundVar->hasExternalFormalLinkage() &&
3163             D->hasExternalFormalLinkage()) {
3164           if (Importer.IsStructurallyEquivalent(D->getType(),
3165                                                 FoundVar->getType())) {
3166             MergeWithVar = FoundVar;
3167             break;
3168           }
3169
3170           const ArrayType *FoundArray
3171             = Importer.getToContext().getAsArrayType(FoundVar->getType());
3172           const ArrayType *TArray
3173             = Importer.getToContext().getAsArrayType(D->getType());
3174           if (FoundArray && TArray) {
3175             if (isa<IncompleteArrayType>(FoundArray) &&
3176                 isa<ConstantArrayType>(TArray)) {
3177               // Import the type.
3178               QualType T = Importer.Import(D->getType());
3179               if (T.isNull())
3180                 return nullptr;
3181
3182               FoundVar->setType(T);
3183               MergeWithVar = FoundVar;
3184               break;
3185             } else if (isa<IncompleteArrayType>(TArray) &&
3186                        isa<ConstantArrayType>(FoundArray)) {
3187               MergeWithVar = FoundVar;
3188               break;
3189             }
3190           }
3191
3192           Importer.ToDiag(Loc, diag::err_odr_variable_type_inconsistent)
3193             << Name << D->getType() << FoundVar->getType();
3194           Importer.ToDiag(FoundVar->getLocation(), diag::note_odr_value_here)
3195             << FoundVar->getType();
3196         }
3197       }
3198
3199       ConflictingDecls.push_back(FoundDecls[I]);
3200     }
3201
3202     if (MergeWithVar) {
3203       // An equivalent variable with external linkage has been found. Link
3204       // the two declarations, then merge them.
3205       Importer.Imported(D, MergeWithVar);
3206
3207       if (VarDecl *DDef = D->getDefinition()) {
3208         if (VarDecl *ExistingDef = MergeWithVar->getDefinition()) {
3209           Importer.ToDiag(ExistingDef->getLocation(),
3210                           diag::err_odr_variable_multiple_def)
3211             << Name;
3212           Importer.FromDiag(DDef->getLocation(), diag::note_odr_defined_here);
3213         } else {
3214           Expr *Init = Importer.Import(DDef->getInit());
3215           MergeWithVar->setInit(Init);
3216           if (DDef->isInitKnownICE()) {
3217             EvaluatedStmt *Eval = MergeWithVar->ensureEvaluatedStmt();
3218             Eval->CheckedICE = true;
3219             Eval->IsICE = DDef->isInitICE();
3220           }
3221         }
3222       }
3223
3224       return MergeWithVar;
3225     }
3226
3227     if (!ConflictingDecls.empty()) {
3228       Name = Importer.HandleNameConflict(Name, DC, IDNS,
3229                                          ConflictingDecls.data(),
3230                                          ConflictingDecls.size());
3231       if (!Name)
3232         return nullptr;
3233     }
3234   }
3235
3236   // Import the type.
3237   QualType T = Importer.Import(D->getType());
3238   if (T.isNull())
3239     return nullptr;
3240
3241   // Create the imported variable.
3242   TypeSourceInfo *TInfo = Importer.Import(D->getTypeSourceInfo());
3243   VarDecl *ToVar = VarDecl::Create(Importer.getToContext(), DC,
3244                                    Importer.Import(D->getInnerLocStart()),
3245                                    Loc, Name.getAsIdentifierInfo(),
3246                                    T, TInfo,
3247                                    D->getStorageClass());
3248   ToVar->setQualifierInfo(Importer.Import(D->getQualifierLoc()));
3249   ToVar->setAccess(D->getAccess());
3250   ToVar->setLexicalDeclContext(LexicalDC);
3251   Importer.Imported(D, ToVar);
3252   LexicalDC->addDeclInternal(ToVar);
3253
3254   if (!D->isFileVarDecl() &&
3255       D->isUsed())
3256     ToVar->setIsUsed();
3257
3258   // Merge the initializer.
3259   if (ImportDefinition(D, ToVar))
3260     return nullptr;
3261
3262   return ToVar;
3263 }
3264
3265 Decl *ASTNodeImporter::VisitImplicitParamDecl(ImplicitParamDecl *D) {
3266   // Parameters are created in the translation unit's context, then moved
3267   // into the function declaration's context afterward.
3268   DeclContext *DC = Importer.getToContext().getTranslationUnitDecl();
3269
3270   // Import the name of this declaration.
3271   DeclarationName Name = Importer.Import(D->getDeclName());
3272   if (D->getDeclName() && !Name)
3273     return nullptr;
3274
3275   // Import the location of this declaration.
3276   SourceLocation Loc = Importer.Import(D->getLocation());
3277
3278   // Import the parameter's type.
3279   QualType T = Importer.Import(D->getType());
3280   if (T.isNull())
3281     return nullptr;
3282
3283   // Create the imported parameter.
3284   ImplicitParamDecl *ToParm
3285     = ImplicitParamDecl::Create(Importer.getToContext(), DC,
3286                                 Loc, Name.getAsIdentifierInfo(),
3287                                 T);
3288   return Importer.Imported(D, ToParm);
3289 }
3290
3291 Decl *ASTNodeImporter::VisitParmVarDecl(ParmVarDecl *D) {
3292   // Parameters are created in the translation unit's context, then moved
3293   // into the function declaration's context afterward.
3294   DeclContext *DC = Importer.getToContext().getTranslationUnitDecl();
3295
3296   // Import the name of this declaration.
3297   DeclarationName Name = Importer.Import(D->getDeclName());
3298   if (D->getDeclName() && !Name)
3299     return nullptr;
3300
3301   // Import the location of this declaration.
3302   SourceLocation Loc = Importer.Import(D->getLocation());
3303
3304   // Import the parameter's type.
3305   QualType T = Importer.Import(D->getType());
3306   if (T.isNull())
3307     return nullptr;
3308
3309   // Create the imported parameter.
3310   TypeSourceInfo *TInfo = Importer.Import(D->getTypeSourceInfo());
3311   ParmVarDecl *ToParm = ParmVarDecl::Create(Importer.getToContext(), DC,
3312                                      Importer.Import(D->getInnerLocStart()),
3313                                             Loc, Name.getAsIdentifierInfo(),
3314                                             T, TInfo, D->getStorageClass(),
3315                                             /*FIXME: Default argument*/nullptr);
3316   ToParm->setHasInheritedDefaultArg(D->hasInheritedDefaultArg());
3317
3318   if (D->isUsed())
3319     ToParm->setIsUsed();
3320
3321   return Importer.Imported(D, ToParm);
3322 }
3323
3324 Decl *ASTNodeImporter::VisitObjCMethodDecl(ObjCMethodDecl *D) {
3325   // Import the major distinguishing characteristics of a method.
3326   DeclContext *DC, *LexicalDC;
3327   DeclarationName Name;
3328   SourceLocation Loc;
3329   NamedDecl *ToD;
3330   if (ImportDeclParts(D, DC, LexicalDC, Name, ToD, Loc))
3331     return nullptr;
3332   if (ToD)
3333     return ToD;
3334
3335   SmallVector<NamedDecl *, 2> FoundDecls;
3336   DC->getRedeclContext()->localUncachedLookup(Name, FoundDecls);
3337   for (unsigned I = 0, N = FoundDecls.size(); I != N; ++I) {
3338     if (ObjCMethodDecl *FoundMethod = dyn_cast<ObjCMethodDecl>(FoundDecls[I])) {
3339       if (FoundMethod->isInstanceMethod() != D->isInstanceMethod())
3340         continue;
3341
3342       // Check return types.
3343       if (!Importer.IsStructurallyEquivalent(D->getReturnType(),
3344                                              FoundMethod->getReturnType())) {
3345         Importer.ToDiag(Loc, diag::err_odr_objc_method_result_type_inconsistent)
3346             << D->isInstanceMethod() << Name << D->getReturnType()
3347             << FoundMethod->getReturnType();
3348         Importer.ToDiag(FoundMethod->getLocation(),
3349                         diag::note_odr_objc_method_here)
3350           << D->isInstanceMethod() << Name;
3351         return nullptr;
3352       }
3353
3354       // Check the number of parameters.
3355       if (D->param_size() != FoundMethod->param_size()) {
3356         Importer.ToDiag(Loc, diag::err_odr_objc_method_num_params_inconsistent)
3357           << D->isInstanceMethod() << Name
3358           << D->param_size() << FoundMethod->param_size();
3359         Importer.ToDiag(FoundMethod->getLocation(),
3360                         diag::note_odr_objc_method_here)
3361           << D->isInstanceMethod() << Name;
3362         return nullptr;
3363       }
3364
3365       // Check parameter types.
3366       for (ObjCMethodDecl::param_iterator P = D->param_begin(),
3367              PEnd = D->param_end(), FoundP = FoundMethod->param_begin();
3368            P != PEnd; ++P, ++FoundP) {
3369         if (!Importer.IsStructurallyEquivalent((*P)->getType(),
3370                                                (*FoundP)->getType())) {
3371           Importer.FromDiag((*P)->getLocation(),
3372                             diag::err_odr_objc_method_param_type_inconsistent)
3373             << D->isInstanceMethod() << Name
3374             << (*P)->getType() << (*FoundP)->getType();
3375           Importer.ToDiag((*FoundP)->getLocation(), diag::note_odr_value_here)
3376             << (*FoundP)->getType();
3377           return nullptr;
3378         }
3379       }
3380
3381       // Check variadic/non-variadic.
3382       // Check the number of parameters.
3383       if (D->isVariadic() != FoundMethod->isVariadic()) {
3384         Importer.ToDiag(Loc, diag::err_odr_objc_method_variadic_inconsistent)
3385           << D->isInstanceMethod() << Name;
3386         Importer.ToDiag(FoundMethod->getLocation(),
3387                         diag::note_odr_objc_method_here)
3388           << D->isInstanceMethod() << Name;
3389         return nullptr;
3390       }
3391
3392       // FIXME: Any other bits we need to merge?
3393       return Importer.Imported(D, FoundMethod);
3394     }
3395   }
3396
3397   // Import the result type.
3398   QualType ResultTy = Importer.Import(D->getReturnType());
3399   if (ResultTy.isNull())
3400     return nullptr;
3401
3402   TypeSourceInfo *ReturnTInfo = Importer.Import(D->getReturnTypeSourceInfo());
3403
3404   ObjCMethodDecl *ToMethod = ObjCMethodDecl::Create(
3405       Importer.getToContext(), Loc, Importer.Import(D->getLocEnd()),
3406       Name.getObjCSelector(), ResultTy, ReturnTInfo, DC, D->isInstanceMethod(),
3407       D->isVariadic(), D->isPropertyAccessor(), D->isImplicit(), D->isDefined(),
3408       D->getImplementationControl(), D->hasRelatedResultType());
3409
3410   // FIXME: When we decide to merge method definitions, we'll need to
3411   // deal with implicit parameters.
3412
3413   // Import the parameters
3414   SmallVector<ParmVarDecl *, 5> ToParams;
3415   for (auto *FromP : D->params()) {
3416     ParmVarDecl *ToP = cast_or_null<ParmVarDecl>(Importer.Import(FromP));
3417     if (!ToP)
3418       return nullptr;
3419
3420     ToParams.push_back(ToP);
3421   }
3422
3423   // Set the parameters.
3424   for (unsigned I = 0, N = ToParams.size(); I != N; ++I) {
3425     ToParams[I]->setOwningFunction(ToMethod);
3426     ToMethod->addDeclInternal(ToParams[I]);
3427   }
3428   SmallVector<SourceLocation, 12> SelLocs;
3429   D->getSelectorLocs(SelLocs);
3430   ToMethod->setMethodParams(Importer.getToContext(), ToParams, SelLocs);
3431
3432   ToMethod->setLexicalDeclContext(LexicalDC);
3433   Importer.Imported(D, ToMethod);
3434   LexicalDC->addDeclInternal(ToMethod);
3435   return ToMethod;
3436 }
3437
3438 Decl *ASTNodeImporter::VisitObjCTypeParamDecl(ObjCTypeParamDecl *D) {
3439   // Import the major distinguishing characteristics of a category.
3440   DeclContext *DC, *LexicalDC;
3441   DeclarationName Name;
3442   SourceLocation Loc;
3443   NamedDecl *ToD;
3444   if (ImportDeclParts(D, DC, LexicalDC, Name, ToD, Loc))
3445     return nullptr;
3446   if (ToD)
3447     return ToD;
3448
3449   TypeSourceInfo *BoundInfo = Importer.Import(D->getTypeSourceInfo());
3450   if (!BoundInfo)
3451     return nullptr;
3452
3453   ObjCTypeParamDecl *Result = ObjCTypeParamDecl::Create(
3454                                 Importer.getToContext(), DC,
3455                                 Importer.Import(D->getLocation()),
3456                                 Name.getAsIdentifierInfo(),
3457                                 Importer.Import(D->getColonLoc()),
3458                                 BoundInfo);
3459   Importer.Imported(D, Result);
3460   Result->setLexicalDeclContext(LexicalDC);
3461   return Result;
3462 }
3463
3464 Decl *ASTNodeImporter::VisitObjCCategoryDecl(ObjCCategoryDecl *D) {
3465   // Import the major distinguishing characteristics of a category.
3466   DeclContext *DC, *LexicalDC;
3467   DeclarationName Name;
3468   SourceLocation Loc;
3469   NamedDecl *ToD;
3470   if (ImportDeclParts(D, DC, LexicalDC, Name, ToD, Loc))
3471     return nullptr;
3472   if (ToD)
3473     return ToD;
3474
3475   ObjCInterfaceDecl *ToInterface
3476     = cast_or_null<ObjCInterfaceDecl>(Importer.Import(D->getClassInterface()));
3477   if (!ToInterface)
3478     return nullptr;
3479
3480   // Determine if we've already encountered this category.
3481   ObjCCategoryDecl *MergeWithCategory
3482     = ToInterface->FindCategoryDeclaration(Name.getAsIdentifierInfo());
3483   ObjCCategoryDecl *ToCategory = MergeWithCategory;
3484   if (!ToCategory) {
3485     ToCategory = ObjCCategoryDecl::Create(Importer.getToContext(), DC,
3486                                           Importer.Import(D->getAtStartLoc()),
3487                                           Loc,
3488                                        Importer.Import(D->getCategoryNameLoc()),
3489                                           Name.getAsIdentifierInfo(),
3490                                           ToInterface,
3491                                           ImportObjCTypeParamList(
3492                                             D->getTypeParamList()),
3493                                        Importer.Import(D->getIvarLBraceLoc()),
3494                                        Importer.Import(D->getIvarRBraceLoc()));
3495     ToCategory->setLexicalDeclContext(LexicalDC);
3496     LexicalDC->addDeclInternal(ToCategory);
3497     Importer.Imported(D, ToCategory);
3498
3499     // Import protocols
3500     SmallVector<ObjCProtocolDecl *, 4> Protocols;
3501     SmallVector<SourceLocation, 4> ProtocolLocs;
3502     ObjCCategoryDecl::protocol_loc_iterator FromProtoLoc
3503       = D->protocol_loc_begin();
3504     for (ObjCCategoryDecl::protocol_iterator FromProto = D->protocol_begin(),
3505                                           FromProtoEnd = D->protocol_end();
3506          FromProto != FromProtoEnd;
3507          ++FromProto, ++FromProtoLoc) {
3508       ObjCProtocolDecl *ToProto
3509         = cast_or_null<ObjCProtocolDecl>(Importer.Import(*FromProto));
3510       if (!ToProto)
3511         return nullptr;
3512       Protocols.push_back(ToProto);
3513       ProtocolLocs.push_back(Importer.Import(*FromProtoLoc));
3514     }
3515
3516     // FIXME: If we're merging, make sure that the protocol list is the same.
3517     ToCategory->setProtocolList(Protocols.data(), Protocols.size(),
3518                                 ProtocolLocs.data(), Importer.getToContext());
3519
3520   } else {
3521     Importer.Imported(D, ToCategory);
3522   }
3523
3524   // Import all of the members of this category.
3525   ImportDeclContext(D);
3526
3527   // If we have an implementation, import it as well.
3528   if (D->getImplementation()) {
3529     ObjCCategoryImplDecl *Impl
3530       = cast_or_null<ObjCCategoryImplDecl>(
3531                                        Importer.Import(D->getImplementation()));
3532     if (!Impl)
3533       return nullptr;
3534
3535     ToCategory->setImplementation(Impl);
3536   }
3537
3538   return ToCategory;
3539 }
3540
3541 bool ASTNodeImporter::ImportDefinition(ObjCProtocolDecl *From,
3542                                        ObjCProtocolDecl *To,
3543                                        ImportDefinitionKind Kind) {
3544   if (To->getDefinition()) {
3545     if (shouldForceImportDeclContext(Kind))
3546       ImportDeclContext(From);
3547     return false;
3548   }
3549
3550   // Start the protocol definition
3551   To->startDefinition();
3552
3553   // Import protocols
3554   SmallVector<ObjCProtocolDecl *, 4> Protocols;
3555   SmallVector<SourceLocation, 4> ProtocolLocs;
3556   ObjCProtocolDecl::protocol_loc_iterator
3557   FromProtoLoc = From->protocol_loc_begin();
3558   for (ObjCProtocolDecl::protocol_iterator FromProto = From->protocol_begin(),
3559                                         FromProtoEnd = From->protocol_end();
3560        FromProto != FromProtoEnd;
3561        ++FromProto, ++FromProtoLoc) {
3562     ObjCProtocolDecl *ToProto
3563       = cast_or_null<ObjCProtocolDecl>(Importer.Import(*FromProto));
3564     if (!ToProto)
3565       return true;
3566     Protocols.push_back(ToProto);
3567     ProtocolLocs.push_back(Importer.Import(*FromProtoLoc));
3568   }
3569
3570   // FIXME: If we're merging, make sure that the protocol list is the same.
3571   To->setProtocolList(Protocols.data(), Protocols.size(),
3572                       ProtocolLocs.data(), Importer.getToContext());
3573
3574   if (shouldForceImportDeclContext(Kind)) {
3575     // Import all of the members of this protocol.
3576     ImportDeclContext(From, /*ForceImport=*/true);
3577   }
3578   return false;
3579 }
3580
3581 Decl *ASTNodeImporter::VisitObjCProtocolDecl(ObjCProtocolDecl *D) {
3582   // If this protocol has a definition in the translation unit we're coming
3583   // from, but this particular declaration is not that definition, import the
3584   // definition and map to that.
3585   ObjCProtocolDecl *Definition = D->getDefinition();
3586   if (Definition && Definition != D) {
3587     Decl *ImportedDef = Importer.Import(Definition);
3588     if (!ImportedDef)
3589       return nullptr;
3590
3591     return Importer.Imported(D, ImportedDef);
3592   }
3593
3594   // Import the major distinguishing characteristics of a protocol.
3595   DeclContext *DC, *LexicalDC;
3596   DeclarationName Name;
3597   SourceLocation Loc;
3598   NamedDecl *ToD;
3599   if (ImportDeclParts(D, DC, LexicalDC, Name, ToD, Loc))
3600     return nullptr;
3601   if (ToD)
3602     return ToD;
3603
3604   ObjCProtocolDecl *MergeWithProtocol = nullptr;
3605   SmallVector<NamedDecl *, 2> FoundDecls;
3606   DC->getRedeclContext()->localUncachedLookup(Name, FoundDecls);
3607   for (unsigned I = 0, N = FoundDecls.size(); I != N; ++I) {
3608     if (!FoundDecls[I]->isInIdentifierNamespace(Decl::IDNS_ObjCProtocol))
3609       continue;
3610
3611     if ((MergeWithProtocol = dyn_cast<ObjCProtocolDecl>(FoundDecls[I])))
3612       break;
3613   }
3614
3615   ObjCProtocolDecl *ToProto = MergeWithProtocol;
3616   if (!ToProto) {
3617     ToProto = ObjCProtocolDecl::Create(Importer.getToContext(), DC,
3618                                        Name.getAsIdentifierInfo(), Loc,
3619                                        Importer.Import(D->getAtStartLoc()),
3620                                        /*PrevDecl=*/nullptr);
3621     ToProto->setLexicalDeclContext(LexicalDC);
3622     LexicalDC->addDeclInternal(ToProto);
3623   }
3624
3625   Importer.Imported(D, ToProto);
3626
3627   if (D->isThisDeclarationADefinition() && ImportDefinition(D, ToProto))
3628     return nullptr;
3629
3630   return ToProto;
3631 }
3632
3633 Decl *ASTNodeImporter::VisitLinkageSpecDecl(LinkageSpecDecl *D) {
3634   DeclContext *DC = Importer.ImportContext(D->getDeclContext());
3635   DeclContext *LexicalDC = Importer.ImportContext(D->getLexicalDeclContext());
3636
3637   SourceLocation ExternLoc = Importer.Import(D->getExternLoc());
3638   SourceLocation LangLoc = Importer.Import(D->getLocation());
3639
3640   bool HasBraces = D->hasBraces();
3641
3642   LinkageSpecDecl *ToLinkageSpec =
3643     LinkageSpecDecl::Create(Importer.getToContext(),
3644                             DC,
3645                             ExternLoc,
3646                             LangLoc,
3647                             D->getLanguage(),
3648                             HasBraces);
3649
3650   if (HasBraces) {
3651     SourceLocation RBraceLoc = Importer.Import(D->getRBraceLoc());
3652     ToLinkageSpec->setRBraceLoc(RBraceLoc);
3653   }
3654
3655   ToLinkageSpec->setLexicalDeclContext(LexicalDC);
3656   LexicalDC->addDeclInternal(ToLinkageSpec);
3657
3658   Importer.Imported(D, ToLinkageSpec);
3659
3660   return ToLinkageSpec;
3661 }
3662
3663 bool ASTNodeImporter::ImportDefinition(ObjCInterfaceDecl *From,
3664                                        ObjCInterfaceDecl *To,
3665                                        ImportDefinitionKind Kind) {
3666   if (To->getDefinition()) {
3667     // Check consistency of superclass.
3668     ObjCInterfaceDecl *FromSuper = From->getSuperClass();
3669     if (FromSuper) {
3670       FromSuper = cast_or_null<ObjCInterfaceDecl>(Importer.Import(FromSuper));
3671       if (!FromSuper)
3672         return true;
3673     }
3674
3675     ObjCInterfaceDecl *ToSuper = To->getSuperClass();
3676     if ((bool)FromSuper != (bool)ToSuper ||
3677         (FromSuper && !declaresSameEntity(FromSuper, ToSuper))) {
3678       Importer.ToDiag(To->getLocation(),
3679                       diag::err_odr_objc_superclass_inconsistent)
3680         << To->getDeclName();
3681       if (ToSuper)
3682         Importer.ToDiag(To->getSuperClassLoc(), diag::note_odr_objc_superclass)
3683           << To->getSuperClass()->getDeclName();
3684       else
3685         Importer.ToDiag(To->getLocation(),
3686                         diag::note_odr_objc_missing_superclass);
3687       if (From->getSuperClass())
3688         Importer.FromDiag(From->getSuperClassLoc(),
3689                           diag::note_odr_objc_superclass)
3690         << From->getSuperClass()->getDeclName();
3691       else
3692         Importer.FromDiag(From->getLocation(),
3693                           diag::note_odr_objc_missing_superclass);
3694     }
3695
3696     if (shouldForceImportDeclContext(Kind))
3697       ImportDeclContext(From);
3698     return false;
3699   }
3700
3701   // Start the definition.
3702   To->startDefinition();
3703
3704   // If this class has a superclass, import it.
3705   if (From->getSuperClass()) {
3706     TypeSourceInfo *SuperTInfo = Importer.Import(From->getSuperClassTInfo());
3707     if (!SuperTInfo)
3708       return true;
3709
3710     To->setSuperClass(SuperTInfo);
3711   }
3712
3713   // Import protocols
3714   SmallVector<ObjCProtocolDecl *, 4> Protocols;
3715   SmallVector<SourceLocation, 4> ProtocolLocs;
3716   ObjCInterfaceDecl::protocol_loc_iterator
3717   FromProtoLoc = From->protocol_loc_begin();
3718
3719   for (ObjCInterfaceDecl::protocol_iterator FromProto = From->protocol_begin(),
3720                                          FromProtoEnd = From->protocol_end();
3721        FromProto != FromProtoEnd;
3722        ++FromProto, ++FromProtoLoc) {
3723     ObjCProtocolDecl *ToProto
3724       = cast_or_null<ObjCProtocolDecl>(Importer.Import(*FromProto));
3725     if (!ToProto)
3726       return true;
3727     Protocols.push_back(ToProto);
3728     ProtocolLocs.push_back(Importer.Import(*FromProtoLoc));
3729   }
3730
3731   // FIXME: If we're merging, make sure that the protocol list is the same.
3732   To->setProtocolList(Protocols.data(), Protocols.size(),
3733                       ProtocolLocs.data(), Importer.getToContext());
3734
3735   // Import categories. When the categories themselves are imported, they'll
3736   // hook themselves into this interface.
3737   for (auto *Cat : From->known_categories())
3738     Importer.Import(Cat);
3739
3740   // If we have an @implementation, import it as well.
3741   if (From->getImplementation()) {
3742     ObjCImplementationDecl *Impl = cast_or_null<ObjCImplementationDecl>(
3743                                      Importer.Import(From->getImplementation()));
3744     if (!Impl)
3745       return true;
3746
3747     To->setImplementation(Impl);
3748   }
3749
3750   if (shouldForceImportDeclContext(Kind)) {
3751     // Import all of the members of this class.
3752     ImportDeclContext(From, /*ForceImport=*/true);
3753   }
3754   return false;
3755 }
3756
3757 ObjCTypeParamList *
3758 ASTNodeImporter::ImportObjCTypeParamList(ObjCTypeParamList *list) {
3759   if (!list)
3760     return nullptr;
3761
3762   SmallVector<ObjCTypeParamDecl *, 4> toTypeParams;
3763   for (auto fromTypeParam : *list) {
3764     auto toTypeParam = cast_or_null<ObjCTypeParamDecl>(
3765                          Importer.Import(fromTypeParam));
3766     if (!toTypeParam)
3767       return nullptr;
3768
3769     toTypeParams.push_back(toTypeParam);
3770   }
3771
3772   return ObjCTypeParamList::create(Importer.getToContext(),
3773                                    Importer.Import(list->getLAngleLoc()),
3774                                    toTypeParams,
3775                                    Importer.Import(list->getRAngleLoc()));
3776 }
3777
3778 Decl *ASTNodeImporter::VisitObjCInterfaceDecl(ObjCInterfaceDecl *D) {
3779   // If this class has a definition in the translation unit we're coming from,
3780   // but this particular declaration is not that definition, import the
3781   // definition and map to that.
3782   ObjCInterfaceDecl *Definition = D->getDefinition();
3783   if (Definition && Definition != D) {
3784     Decl *ImportedDef = Importer.Import(Definition);
3785     if (!ImportedDef)
3786       return nullptr;
3787
3788     return Importer.Imported(D, ImportedDef);
3789   }
3790
3791   // Import the major distinguishing characteristics of an @interface.
3792   DeclContext *DC, *LexicalDC;
3793   DeclarationName Name;
3794   SourceLocation Loc;
3795   NamedDecl *ToD;
3796   if (ImportDeclParts(D, DC, LexicalDC, Name, ToD, Loc))
3797     return nullptr;
3798   if (ToD)
3799     return ToD;
3800
3801   // Look for an existing interface with the same name.
3802   ObjCInterfaceDecl *MergeWithIface = nullptr;
3803   SmallVector<NamedDecl *, 2> FoundDecls;
3804   DC->getRedeclContext()->localUncachedLookup(Name, FoundDecls);
3805   for (unsigned I = 0, N = FoundDecls.size(); I != N; ++I) {
3806     if (!FoundDecls[I]->isInIdentifierNamespace(Decl::IDNS_Ordinary))
3807       continue;
3808
3809     if ((MergeWithIface = dyn_cast<ObjCInterfaceDecl>(FoundDecls[I])))
3810       break;
3811   }
3812
3813   // Create an interface declaration, if one does not already exist.
3814   ObjCInterfaceDecl *ToIface = MergeWithIface;
3815   if (!ToIface) {
3816     ToIface = ObjCInterfaceDecl::Create(Importer.getToContext(), DC,
3817                                         Importer.Import(D->getAtStartLoc()),
3818                                         Name.getAsIdentifierInfo(),
3819                                         ImportObjCTypeParamList(
3820                                           D->getTypeParamListAsWritten()),
3821                                         /*PrevDecl=*/nullptr, Loc,
3822                                         D->isImplicitInterfaceDecl());
3823     ToIface->setLexicalDeclContext(LexicalDC);
3824     LexicalDC->addDeclInternal(ToIface);
3825   }
3826   Importer.Imported(D, ToIface);
3827
3828   if (D->isThisDeclarationADefinition() && ImportDefinition(D, ToIface))
3829     return nullptr;
3830
3831   return ToIface;
3832 }
3833
3834 Decl *ASTNodeImporter::VisitObjCCategoryImplDecl(ObjCCategoryImplDecl *D) {
3835   ObjCCategoryDecl *Category = cast_or_null<ObjCCategoryDecl>(
3836                                         Importer.Import(D->getCategoryDecl()));
3837   if (!Category)
3838     return nullptr;
3839
3840   ObjCCategoryImplDecl *ToImpl = Category->getImplementation();
3841   if (!ToImpl) {
3842     DeclContext *DC = Importer.ImportContext(D->getDeclContext());
3843     if (!DC)
3844       return nullptr;
3845
3846     SourceLocation CategoryNameLoc = Importer.Import(D->getCategoryNameLoc());
3847     ToImpl = ObjCCategoryImplDecl::Create(Importer.getToContext(), DC,
3848                                           Importer.Import(D->getIdentifier()),
3849                                           Category->getClassInterface(),
3850                                           Importer.Import(D->getLocation()),
3851                                           Importer.Import(D->getAtStartLoc()),
3852                                           CategoryNameLoc);
3853
3854     DeclContext *LexicalDC = DC;
3855     if (D->getDeclContext() != D->getLexicalDeclContext()) {
3856       LexicalDC = Importer.ImportContext(D->getLexicalDeclContext());
3857       if (!LexicalDC)
3858         return nullptr;
3859
3860       ToImpl->setLexicalDeclContext(LexicalDC);
3861     }
3862
3863     LexicalDC->addDeclInternal(ToImpl);
3864     Category->setImplementation(ToImpl);
3865   }
3866
3867   Importer.Imported(D, ToImpl);
3868   ImportDeclContext(D);
3869   return ToImpl;
3870 }
3871
3872 Decl *ASTNodeImporter::VisitObjCImplementationDecl(ObjCImplementationDecl *D) {
3873   // Find the corresponding interface.
3874   ObjCInterfaceDecl *Iface = cast_or_null<ObjCInterfaceDecl>(
3875                                        Importer.Import(D->getClassInterface()));
3876   if (!Iface)
3877     return nullptr;
3878
3879   // Import the superclass, if any.
3880   ObjCInterfaceDecl *Super = nullptr;
3881   if (D->getSuperClass()) {
3882     Super = cast_or_null<ObjCInterfaceDecl>(
3883                                           Importer.Import(D->getSuperClass()));
3884     if (!Super)
3885       return nullptr;
3886   }
3887
3888   ObjCImplementationDecl *Impl = Iface->getImplementation();
3889   if (!Impl) {
3890     // We haven't imported an implementation yet. Create a new @implementation
3891     // now.
3892     Impl = ObjCImplementationDecl::Create(Importer.getToContext(),
3893                                   Importer.ImportContext(D->getDeclContext()),
3894                                           Iface, Super,
3895                                           Importer.Import(D->getLocation()),
3896                                           Importer.Import(D->getAtStartLoc()),
3897                                           Importer.Import(D->getSuperClassLoc()),
3898                                           Importer.Import(D->getIvarLBraceLoc()),
3899                                           Importer.Import(D->getIvarRBraceLoc()));
3900
3901     if (D->getDeclContext() != D->getLexicalDeclContext()) {
3902       DeclContext *LexicalDC
3903         = Importer.ImportContext(D->getLexicalDeclContext());
3904       if (!LexicalDC)
3905         return nullptr;
3906       Impl->setLexicalDeclContext(LexicalDC);
3907     }
3908
3909     // Associate the implementation with the class it implements.
3910     Iface->setImplementation(Impl);
3911     Importer.Imported(D, Iface->getImplementation());
3912   } else {
3913     Importer.Imported(D, Iface->getImplementation());
3914
3915     // Verify that the existing @implementation has the same superclass.
3916     if ((Super && !Impl->getSuperClass()) ||
3917         (!Super && Impl->getSuperClass()) ||
3918         (Super && Impl->getSuperClass() &&
3919          !declaresSameEntity(Super->getCanonicalDecl(),
3920                              Impl->getSuperClass()))) {
3921       Importer.ToDiag(Impl->getLocation(),
3922                       diag::err_odr_objc_superclass_inconsistent)
3923         << Iface->getDeclName();
3924       // FIXME: It would be nice to have the location of the superclass
3925       // below.
3926       if (Impl->getSuperClass())
3927         Importer.ToDiag(Impl->getLocation(),
3928                         diag::note_odr_objc_superclass)
3929         << Impl->getSuperClass()->getDeclName();
3930       else
3931         Importer.ToDiag(Impl->getLocation(),
3932                         diag::note_odr_objc_missing_superclass);
3933       if (D->getSuperClass())
3934         Importer.FromDiag(D->getLocation(),
3935                           diag::note_odr_objc_superclass)
3936         << D->getSuperClass()->getDeclName();
3937       else
3938         Importer.FromDiag(D->getLocation(),
3939                           diag::note_odr_objc_missing_superclass);
3940       return nullptr;
3941     }
3942   }
3943
3944   // Import all of the members of this @implementation.
3945   ImportDeclContext(D);
3946
3947   return Impl;
3948 }
3949
3950 Decl *ASTNodeImporter::VisitObjCPropertyDecl(ObjCPropertyDecl *D) {
3951   // Import the major distinguishing characteristics of an @property.
3952   DeclContext *DC, *LexicalDC;
3953   DeclarationName Name;
3954   SourceLocation Loc;
3955   NamedDecl *ToD;
3956   if (ImportDeclParts(D, DC, LexicalDC, Name, ToD, Loc))
3957     return nullptr;
3958   if (ToD)
3959     return ToD;
3960
3961   // Check whether we have already imported this property.
3962   SmallVector<NamedDecl *, 2> FoundDecls;
3963   DC->getRedeclContext()->localUncachedLookup(Name, FoundDecls);
3964   for (unsigned I = 0, N = FoundDecls.size(); I != N; ++I) {
3965     if (ObjCPropertyDecl *FoundProp
3966                                 = dyn_cast<ObjCPropertyDecl>(FoundDecls[I])) {
3967       // Check property types.
3968       if (!Importer.IsStructurallyEquivalent(D->getType(),
3969                                              FoundProp->getType())) {
3970         Importer.ToDiag(Loc, diag::err_odr_objc_property_type_inconsistent)
3971           << Name << D->getType() << FoundProp->getType();
3972         Importer.ToDiag(FoundProp->getLocation(), diag::note_odr_value_here)
3973           << FoundProp->getType();
3974         return nullptr;
3975       }
3976
3977       // FIXME: Check property attributes, getters, setters, etc.?
3978
3979       // Consider these properties to be equivalent.
3980       Importer.Imported(D, FoundProp);
3981       return FoundProp;
3982     }
3983   }
3984
3985   // Import the type.
3986   TypeSourceInfo *TSI = Importer.Import(D->getTypeSourceInfo());
3987   if (!TSI)
3988     return nullptr;
3989
3990   // Create the new property.
3991   ObjCPropertyDecl *ToProperty
3992     = ObjCPropertyDecl::Create(Importer.getToContext(), DC, Loc,
3993                                Name.getAsIdentifierInfo(),
3994                                Importer.Import(D->getAtLoc()),
3995                                Importer.Import(D->getLParenLoc()),
3996                                Importer.Import(D->getType()),
3997                                TSI,
3998                                D->getPropertyImplementation());
3999   Importer.Imported(D, ToProperty);
4000   ToProperty->setLexicalDeclContext(LexicalDC);
4001   LexicalDC->addDeclInternal(ToProperty);
4002
4003   ToProperty->setPropertyAttributes(D->getPropertyAttributes());
4004   ToProperty->setPropertyAttributesAsWritten(
4005                                       D->getPropertyAttributesAsWritten());
4006   ToProperty->setGetterName(Importer.Import(D->getGetterName()));
4007   ToProperty->setSetterName(Importer.Import(D->getSetterName()));
4008   ToProperty->setGetterMethodDecl(
4009      cast_or_null<ObjCMethodDecl>(Importer.Import(D->getGetterMethodDecl())));
4010   ToProperty->setSetterMethodDecl(
4011      cast_or_null<ObjCMethodDecl>(Importer.Import(D->getSetterMethodDecl())));
4012   ToProperty->setPropertyIvarDecl(
4013        cast_or_null<ObjCIvarDecl>(Importer.Import(D->getPropertyIvarDecl())));
4014   return ToProperty;
4015 }
4016
4017 Decl *ASTNodeImporter::VisitObjCPropertyImplDecl(ObjCPropertyImplDecl *D) {
4018   ObjCPropertyDecl *Property = cast_or_null<ObjCPropertyDecl>(
4019                                         Importer.Import(D->getPropertyDecl()));
4020   if (!Property)
4021     return nullptr;
4022
4023   DeclContext *DC = Importer.ImportContext(D->getDeclContext());
4024   if (!DC)
4025     return nullptr;
4026
4027   // Import the lexical declaration context.
4028   DeclContext *LexicalDC = DC;
4029   if (D->getDeclContext() != D->getLexicalDeclContext()) {
4030     LexicalDC = Importer.ImportContext(D->getLexicalDeclContext());
4031     if (!LexicalDC)
4032       return nullptr;
4033   }
4034
4035   ObjCImplDecl *InImpl = dyn_cast<ObjCImplDecl>(LexicalDC);
4036   if (!InImpl)
4037     return nullptr;
4038
4039   // Import the ivar (for an @synthesize).
4040   ObjCIvarDecl *Ivar = nullptr;
4041   if (D->getPropertyIvarDecl()) {
4042     Ivar = cast_or_null<ObjCIvarDecl>(
4043                                     Importer.Import(D->getPropertyIvarDecl()));
4044     if (!Ivar)
4045       return nullptr;
4046   }
4047
4048   ObjCPropertyImplDecl *ToImpl
4049     = InImpl->FindPropertyImplDecl(Property->getIdentifier());
4050   if (!ToImpl) {
4051     ToImpl = ObjCPropertyImplDecl::Create(Importer.getToContext(), DC,
4052                                           Importer.Import(D->getLocStart()),
4053                                           Importer.Import(D->getLocation()),
4054                                           Property,
4055                                           D->getPropertyImplementation(),
4056                                           Ivar,
4057                                   Importer.Import(D->getPropertyIvarDeclLoc()));
4058     ToImpl->setLexicalDeclContext(LexicalDC);
4059     Importer.Imported(D, ToImpl);
4060     LexicalDC->addDeclInternal(ToImpl);
4061   } else {
4062     // Check that we have the same kind of property implementation (@synthesize
4063     // vs. @dynamic).
4064     if (D->getPropertyImplementation() != ToImpl->getPropertyImplementation()) {
4065       Importer.ToDiag(ToImpl->getLocation(),
4066                       diag::err_odr_objc_property_impl_kind_inconsistent)
4067         << Property->getDeclName()
4068         << (ToImpl->getPropertyImplementation()
4069                                               == ObjCPropertyImplDecl::Dynamic);
4070       Importer.FromDiag(D->getLocation(),
4071                         diag::note_odr_objc_property_impl_kind)
4072         << D->getPropertyDecl()->getDeclName()
4073         << (D->getPropertyImplementation() == ObjCPropertyImplDecl::Dynamic);
4074       return nullptr;
4075     }
4076
4077     // For @synthesize, check that we have the same
4078     if (D->getPropertyImplementation() == ObjCPropertyImplDecl::Synthesize &&
4079         Ivar != ToImpl->getPropertyIvarDecl()) {
4080       Importer.ToDiag(ToImpl->getPropertyIvarDeclLoc(),
4081                       diag::err_odr_objc_synthesize_ivar_inconsistent)
4082         << Property->getDeclName()
4083         << ToImpl->getPropertyIvarDecl()->getDeclName()
4084         << Ivar->getDeclName();
4085       Importer.FromDiag(D->getPropertyIvarDeclLoc(),
4086                         diag::note_odr_objc_synthesize_ivar_here)
4087         << D->getPropertyIvarDecl()->getDeclName();
4088       return nullptr;
4089     }
4090
4091     // Merge the existing implementation with the new implementation.
4092     Importer.Imported(D, ToImpl);
4093   }
4094
4095   return ToImpl;
4096 }
4097
4098 Decl *ASTNodeImporter::VisitTemplateTypeParmDecl(TemplateTypeParmDecl *D) {
4099   // For template arguments, we adopt the translation unit as our declaration
4100   // context. This context will be fixed when the actual template declaration
4101   // is created.
4102
4103   // FIXME: Import default argument.
4104   return TemplateTypeParmDecl::Create(Importer.getToContext(),
4105                               Importer.getToContext().getTranslationUnitDecl(),
4106                                       Importer.Import(D->getLocStart()),
4107                                       Importer.Import(D->getLocation()),
4108                                       D->getDepth(),
4109                                       D->getIndex(),
4110                                       Importer.Import(D->getIdentifier()),
4111                                       D->wasDeclaredWithTypename(),
4112                                       D->isParameterPack());
4113 }
4114
4115 Decl *
4116 ASTNodeImporter::VisitNonTypeTemplateParmDecl(NonTypeTemplateParmDecl *D) {
4117   // Import the name of this declaration.
4118   DeclarationName Name = Importer.Import(D->getDeclName());
4119   if (D->getDeclName() && !Name)
4120     return nullptr;
4121
4122   // Import the location of this declaration.
4123   SourceLocation Loc = Importer.Import(D->getLocation());
4124
4125   // Import the type of this declaration.
4126   QualType T = Importer.Import(D->getType());
4127   if (T.isNull())
4128     return nullptr;
4129
4130   // Import type-source information.
4131   TypeSourceInfo *TInfo = Importer.Import(D->getTypeSourceInfo());
4132   if (D->getTypeSourceInfo() && !TInfo)
4133     return nullptr;
4134
4135   // FIXME: Import default argument.
4136
4137   return NonTypeTemplateParmDecl::Create(Importer.getToContext(),
4138                                Importer.getToContext().getTranslationUnitDecl(),
4139                                          Importer.Import(D->getInnerLocStart()),
4140                                          Loc, D->getDepth(), D->getPosition(),
4141                                          Name.getAsIdentifierInfo(),
4142                                          T, D->isParameterPack(), TInfo);
4143 }
4144
4145 Decl *
4146 ASTNodeImporter::VisitTemplateTemplateParmDecl(TemplateTemplateParmDecl *D) {
4147   // Import the name of this declaration.
4148   DeclarationName Name = Importer.Import(D->getDeclName());
4149   if (D->getDeclName() && !Name)
4150     return nullptr;
4151
4152   // Import the location of this declaration.
4153   SourceLocation Loc = Importer.Import(D->getLocation());
4154
4155   // Import template parameters.
4156   TemplateParameterList *TemplateParams
4157     = ImportTemplateParameterList(D->getTemplateParameters());
4158   if (!TemplateParams)
4159     return nullptr;
4160
4161   // FIXME: Import default argument.
4162
4163   return TemplateTemplateParmDecl::Create(Importer.getToContext(),
4164                               Importer.getToContext().getTranslationUnitDecl(),
4165                                           Loc, D->getDepth(), D->getPosition(),
4166                                           D->isParameterPack(),
4167                                           Name.getAsIdentifierInfo(),
4168                                           TemplateParams);
4169 }
4170
4171 Decl *ASTNodeImporter::VisitClassTemplateDecl(ClassTemplateDecl *D) {
4172   // If this record has a definition in the translation unit we're coming from,
4173   // but this particular declaration is not that definition, import the
4174   // definition and map to that.
4175   CXXRecordDecl *Definition
4176     = cast_or_null<CXXRecordDecl>(D->getTemplatedDecl()->getDefinition());
4177   if (Definition && Definition != D->getTemplatedDecl()) {
4178     Decl *ImportedDef
4179       = Importer.Import(Definition->getDescribedClassTemplate());
4180     if (!ImportedDef)
4181       return nullptr;
4182
4183     return Importer.Imported(D, ImportedDef);
4184   }
4185
4186   // Import the major distinguishing characteristics of this class template.
4187   DeclContext *DC, *LexicalDC;
4188   DeclarationName Name;
4189   SourceLocation Loc;
4190   NamedDecl *ToD;
4191   if (ImportDeclParts(D, DC, LexicalDC, Name, ToD, Loc))
4192     return nullptr;
4193   if (ToD)
4194     return ToD;
4195
4196   // We may already have a template of the same name; try to find and match it.
4197   if (!DC->isFunctionOrMethod()) {
4198     SmallVector<NamedDecl *, 4> ConflictingDecls;
4199     SmallVector<NamedDecl *, 2> FoundDecls;
4200     DC->getRedeclContext()->localUncachedLookup(Name, FoundDecls);
4201     for (unsigned I = 0, N = FoundDecls.size(); I != N; ++I) {
4202       if (!FoundDecls[I]->isInIdentifierNamespace(Decl::IDNS_Ordinary))
4203         continue;
4204
4205       Decl *Found = FoundDecls[I];
4206       if (ClassTemplateDecl *FoundTemplate
4207                                         = dyn_cast<ClassTemplateDecl>(Found)) {
4208         if (IsStructuralMatch(D, FoundTemplate)) {
4209           // The class templates structurally match; call it the same template.
4210           // FIXME: We may be filling in a forward declaration here. Handle
4211           // this case!
4212           Importer.Imported(D->getTemplatedDecl(),
4213                             FoundTemplate->getTemplatedDecl());
4214           return Importer.Imported(D, FoundTemplate);
4215         }
4216       }
4217
4218       ConflictingDecls.push_back(FoundDecls[I]);
4219     }
4220
4221     if (!ConflictingDecls.empty()) {
4222       Name = Importer.HandleNameConflict(Name, DC, Decl::IDNS_Ordinary,
4223                                          ConflictingDecls.data(),
4224                                          ConflictingDecls.size());
4225     }
4226
4227     if (!Name)
4228       return nullptr;
4229   }
4230
4231   CXXRecordDecl *DTemplated = D->getTemplatedDecl();
4232
4233   // Create the declaration that is being templated.
4234   SourceLocation StartLoc = Importer.Import(DTemplated->getLocStart());
4235   SourceLocation IdLoc = Importer.Import(DTemplated->getLocation());
4236   CXXRecordDecl *D2Templated = CXXRecordDecl::Create(Importer.getToContext(),
4237                                                      DTemplated->getTagKind(),
4238                                                      DC, StartLoc, IdLoc,
4239                                                    Name.getAsIdentifierInfo());
4240   D2Templated->setAccess(DTemplated->getAccess());
4241   D2Templated->setQualifierInfo(Importer.Import(DTemplated->getQualifierLoc()));
4242   D2Templated->setLexicalDeclContext(LexicalDC);
4243
4244   // Create the class template declaration itself.
4245   TemplateParameterList *TemplateParams
4246     = ImportTemplateParameterList(D->getTemplateParameters());
4247   if (!TemplateParams)
4248     return nullptr;
4249
4250   ClassTemplateDecl *D2 = ClassTemplateDecl::Create(Importer.getToContext(), DC,
4251                                                     Loc, Name, TemplateParams,
4252                                                     D2Templated,
4253                                                     /*PrevDecl=*/nullptr);
4254   D2Templated->setDescribedClassTemplate(D2);
4255
4256   D2->setAccess(D->getAccess());
4257   D2->setLexicalDeclContext(LexicalDC);
4258   LexicalDC->addDeclInternal(D2);
4259
4260   // Note the relationship between the class templates.
4261   Importer.Imported(D, D2);
4262   Importer.Imported(DTemplated, D2Templated);
4263
4264   if (DTemplated->isCompleteDefinition() &&
4265       !D2Templated->isCompleteDefinition()) {
4266     // FIXME: Import definition!
4267   }
4268
4269   return D2;
4270 }
4271
4272 Decl *ASTNodeImporter::VisitClassTemplateSpecializationDecl(
4273                                           ClassTemplateSpecializationDecl *D) {
4274   // If this record has a definition in the translation unit we're coming from,
4275   // but this particular declaration is not that definition, import the
4276   // definition and map to that.
4277   TagDecl *Definition = D->getDefinition();
4278   if (Definition && Definition != D) {
4279     Decl *ImportedDef = Importer.Import(Definition);
4280     if (!ImportedDef)
4281       return nullptr;
4282
4283     return Importer.Imported(D, ImportedDef);
4284   }
4285
4286   ClassTemplateDecl *ClassTemplate
4287     = cast_or_null<ClassTemplateDecl>(Importer.Import(
4288                                                  D->getSpecializedTemplate()));
4289   if (!ClassTemplate)
4290     return nullptr;
4291
4292   // Import the context of this declaration.
4293   DeclContext *DC = ClassTemplate->getDeclContext();
4294   if (!DC)
4295     return nullptr;
4296
4297   DeclContext *LexicalDC = DC;
4298   if (D->getDeclContext() != D->getLexicalDeclContext()) {
4299     LexicalDC = Importer.ImportContext(D->getLexicalDeclContext());
4300     if (!LexicalDC)
4301       return nullptr;
4302   }
4303
4304   // Import the location of this declaration.
4305   SourceLocation StartLoc = Importer.Import(D->getLocStart());
4306   SourceLocation IdLoc = Importer.Import(D->getLocation());
4307
4308   // Import template arguments.
4309   SmallVector<TemplateArgument, 2> TemplateArgs;
4310   if (ImportTemplateArguments(D->getTemplateArgs().data(),
4311                               D->getTemplateArgs().size(),
4312                               TemplateArgs))
4313     return nullptr;
4314
4315   // Try to find an existing specialization with these template arguments.
4316   void *InsertPos = nullptr;
4317   ClassTemplateSpecializationDecl *D2
4318     = ClassTemplate->findSpecialization(TemplateArgs, InsertPos);
4319   if (D2) {
4320     // We already have a class template specialization with these template
4321     // arguments.
4322
4323     // FIXME: Check for specialization vs. instantiation errors.
4324
4325     if (RecordDecl *FoundDef = D2->getDefinition()) {
4326       if (!D->isCompleteDefinition() || IsStructuralMatch(D, FoundDef)) {
4327         // The record types structurally match, or the "from" translation
4328         // unit only had a forward declaration anyway; call it the same
4329         // function.
4330         return Importer.Imported(D, FoundDef);
4331       }
4332     }
4333   } else {
4334     // Create a new specialization.
4335     D2 = ClassTemplateSpecializationDecl::Create(Importer.getToContext(),
4336                                                  D->getTagKind(), DC,
4337                                                  StartLoc, IdLoc,
4338                                                  ClassTemplate,
4339                                                  TemplateArgs.data(),
4340                                                  TemplateArgs.size(),
4341                                                  /*PrevDecl=*/nullptr);
4342     D2->setSpecializationKind(D->getSpecializationKind());
4343
4344     // Add this specialization to the class template.
4345     ClassTemplate->AddSpecialization(D2, InsertPos);
4346
4347     // Import the qualifier, if any.
4348     D2->setQualifierInfo(Importer.Import(D->getQualifierLoc()));
4349
4350     // Add the specialization to this context.
4351     D2->setLexicalDeclContext(LexicalDC);
4352     LexicalDC->addDeclInternal(D2);
4353   }
4354   Importer.Imported(D, D2);
4355
4356   if (D->isCompleteDefinition() && ImportDefinition(D, D2))
4357     return nullptr;
4358
4359   return D2;
4360 }
4361
4362 Decl *ASTNodeImporter::VisitVarTemplateDecl(VarTemplateDecl *D) {
4363   // If this variable has a definition in the translation unit we're coming
4364   // from,
4365   // but this particular declaration is not that definition, import the
4366   // definition and map to that.
4367   VarDecl *Definition =
4368       cast_or_null<VarDecl>(D->getTemplatedDecl()->getDefinition());
4369   if (Definition && Definition != D->getTemplatedDecl()) {
4370     Decl *ImportedDef = Importer.Import(Definition->getDescribedVarTemplate());
4371     if (!ImportedDef)
4372       return nullptr;
4373
4374     return Importer.Imported(D, ImportedDef);
4375   }
4376
4377   // Import the major distinguishing characteristics of this variable template.
4378   DeclContext *DC, *LexicalDC;
4379   DeclarationName Name;
4380   SourceLocation Loc;
4381   NamedDecl *ToD;
4382   if (ImportDeclParts(D, DC, LexicalDC, Name, ToD, Loc))
4383     return nullptr;
4384   if (ToD)
4385     return ToD;
4386
4387   // We may already have a template of the same name; try to find and match it.
4388   assert(!DC->isFunctionOrMethod() &&
4389          "Variable templates cannot be declared at function scope");
4390   SmallVector<NamedDecl *, 4> ConflictingDecls;
4391   SmallVector<NamedDecl *, 2> FoundDecls;
4392   DC->getRedeclContext()->localUncachedLookup(Name, FoundDecls);
4393   for (unsigned I = 0, N = FoundDecls.size(); I != N; ++I) {
4394     if (!FoundDecls[I]->isInIdentifierNamespace(Decl::IDNS_Ordinary))
4395       continue;
4396
4397     Decl *Found = FoundDecls[I];
4398     if (VarTemplateDecl *FoundTemplate = dyn_cast<VarTemplateDecl>(Found)) {
4399       if (IsStructuralMatch(D, FoundTemplate)) {
4400         // The variable templates structurally match; call it the same template.
4401         Importer.Imported(D->getTemplatedDecl(),
4402                           FoundTemplate->getTemplatedDecl());
4403         return Importer.Imported(D, FoundTemplate);
4404       }
4405     }
4406
4407     ConflictingDecls.push_back(FoundDecls[I]);
4408   }
4409
4410   if (!ConflictingDecls.empty()) {
4411     Name = Importer.HandleNameConflict(Name, DC, Decl::IDNS_Ordinary,
4412                                        ConflictingDecls.data(),
4413                                        ConflictingDecls.size());
4414   }
4415
4416   if (!Name)
4417     return nullptr;
4418
4419   VarDecl *DTemplated = D->getTemplatedDecl();
4420
4421   // Import the type.
4422   QualType T = Importer.Import(DTemplated->getType());
4423   if (T.isNull())
4424     return nullptr;
4425
4426   // Create the declaration that is being templated.
4427   SourceLocation StartLoc = Importer.Import(DTemplated->getLocStart());
4428   SourceLocation IdLoc = Importer.Import(DTemplated->getLocation());
4429   TypeSourceInfo *TInfo = Importer.Import(DTemplated->getTypeSourceInfo());
4430   VarDecl *D2Templated = VarDecl::Create(Importer.getToContext(), DC, StartLoc,
4431                                          IdLoc, Name.getAsIdentifierInfo(), T,
4432                                          TInfo, DTemplated->getStorageClass());
4433   D2Templated->setAccess(DTemplated->getAccess());
4434   D2Templated->setQualifierInfo(Importer.Import(DTemplated->getQualifierLoc()));
4435   D2Templated->setLexicalDeclContext(LexicalDC);
4436
4437   // Importer.Imported(DTemplated, D2Templated);
4438   // LexicalDC->addDeclInternal(D2Templated);
4439
4440   // Merge the initializer.
4441   if (ImportDefinition(DTemplated, D2Templated))
4442     return nullptr;
4443
4444   // Create the variable template declaration itself.
4445   TemplateParameterList *TemplateParams =
4446       ImportTemplateParameterList(D->getTemplateParameters());
4447   if (!TemplateParams)
4448     return nullptr;
4449
4450   VarTemplateDecl *D2 = VarTemplateDecl::Create(
4451       Importer.getToContext(), DC, Loc, Name, TemplateParams, D2Templated);
4452   D2Templated->setDescribedVarTemplate(D2);
4453
4454   D2->setAccess(D->getAccess());
4455   D2->setLexicalDeclContext(LexicalDC);
4456   LexicalDC->addDeclInternal(D2);
4457
4458   // Note the relationship between the variable templates.
4459   Importer.Imported(D, D2);
4460   Importer.Imported(DTemplated, D2Templated);
4461
4462   if (DTemplated->isThisDeclarationADefinition() &&
4463       !D2Templated->isThisDeclarationADefinition()) {
4464     // FIXME: Import definition!
4465   }
4466
4467   return D2;
4468 }
4469
4470 Decl *ASTNodeImporter::VisitVarTemplateSpecializationDecl(
4471     VarTemplateSpecializationDecl *D) {
4472   // If this record has a definition in the translation unit we're coming from,
4473   // but this particular declaration is not that definition, import the
4474   // definition and map to that.
4475   VarDecl *Definition = D->getDefinition();
4476   if (Definition && Definition != D) {
4477     Decl *ImportedDef = Importer.Import(Definition);
4478     if (!ImportedDef)
4479       return nullptr;
4480
4481     return Importer.Imported(D, ImportedDef);
4482   }
4483
4484   VarTemplateDecl *VarTemplate = cast_or_null<VarTemplateDecl>(
4485       Importer.Import(D->getSpecializedTemplate()));
4486   if (!VarTemplate)
4487     return nullptr;
4488
4489   // Import the context of this declaration.
4490   DeclContext *DC = VarTemplate->getDeclContext();
4491   if (!DC)
4492     return nullptr;
4493
4494   DeclContext *LexicalDC = DC;
4495   if (D->getDeclContext() != D->getLexicalDeclContext()) {
4496     LexicalDC = Importer.ImportContext(D->getLexicalDeclContext());
4497     if (!LexicalDC)
4498       return nullptr;
4499   }
4500
4501   // Import the location of this declaration.
4502   SourceLocation StartLoc = Importer.Import(D->getLocStart());
4503   SourceLocation IdLoc = Importer.Import(D->getLocation());
4504
4505   // Import template arguments.
4506   SmallVector<TemplateArgument, 2> TemplateArgs;
4507   if (ImportTemplateArguments(D->getTemplateArgs().data(),
4508                               D->getTemplateArgs().size(), TemplateArgs))
4509     return nullptr;
4510
4511   // Try to find an existing specialization with these template arguments.
4512   void *InsertPos = nullptr;
4513   VarTemplateSpecializationDecl *D2 = VarTemplate->findSpecialization(
4514       TemplateArgs, InsertPos);
4515   if (D2) {
4516     // We already have a variable template specialization with these template
4517     // arguments.
4518
4519     // FIXME: Check for specialization vs. instantiation errors.
4520
4521     if (VarDecl *FoundDef = D2->getDefinition()) {
4522       if (!D->isThisDeclarationADefinition() ||
4523           IsStructuralMatch(D, FoundDef)) {
4524         // The record types structurally match, or the "from" translation
4525         // unit only had a forward declaration anyway; call it the same
4526         // variable.
4527         return Importer.Imported(D, FoundDef);
4528       }
4529     }
4530   } else {
4531
4532     // Import the type.
4533     QualType T = Importer.Import(D->getType());
4534     if (T.isNull())
4535       return nullptr;
4536     TypeSourceInfo *TInfo = Importer.Import(D->getTypeSourceInfo());
4537
4538     // Create a new specialization.
4539     D2 = VarTemplateSpecializationDecl::Create(
4540         Importer.getToContext(), DC, StartLoc, IdLoc, VarTemplate, T, TInfo,
4541         D->getStorageClass(), TemplateArgs.data(), TemplateArgs.size());
4542     D2->setSpecializationKind(D->getSpecializationKind());
4543     D2->setTemplateArgsInfo(D->getTemplateArgsInfo());
4544
4545     // Add this specialization to the class template.
4546     VarTemplate->AddSpecialization(D2, InsertPos);
4547
4548     // Import the qualifier, if any.
4549     D2->setQualifierInfo(Importer.Import(D->getQualifierLoc()));
4550
4551     // Add the specialization to this context.
4552     D2->setLexicalDeclContext(LexicalDC);
4553     LexicalDC->addDeclInternal(D2);
4554   }
4555   Importer.Imported(D, D2);
4556
4557   if (D->isThisDeclarationADefinition() && ImportDefinition(D, D2))
4558     return nullptr;
4559
4560   return D2;
4561 }
4562
4563 //----------------------------------------------------------------------------
4564 // Import Statements
4565 //----------------------------------------------------------------------------
4566
4567 DeclGroupRef ASTNodeImporter::ImportDeclGroup(DeclGroupRef DG) {
4568   if (DG.isNull())
4569     return DeclGroupRef::Create(Importer.getToContext(), nullptr, 0);
4570   size_t NumDecls = DG.end() - DG.begin();
4571   SmallVector<Decl *, 1> ToDecls(NumDecls);
4572   auto &_Importer = this->Importer;
4573   std::transform(DG.begin(), DG.end(), ToDecls.begin(),
4574     [&_Importer](Decl *D) -> Decl * {
4575       return _Importer.Import(D);
4576     });
4577   return DeclGroupRef::Create(Importer.getToContext(),
4578                               ToDecls.begin(),
4579                               NumDecls);
4580 }
4581
4582  Stmt *ASTNodeImporter::VisitStmt(Stmt *S) {
4583    Importer.FromDiag(S->getLocStart(), diag::err_unsupported_ast_node)
4584      << S->getStmtClassName();
4585    return nullptr;
4586  }
4587
4588 Stmt *ASTNodeImporter::VisitDeclStmt(DeclStmt *S) {
4589   DeclGroupRef ToDG = ImportDeclGroup(S->getDeclGroup());
4590   for (Decl *ToD : ToDG) {
4591     if (!ToD)
4592       return nullptr;
4593   }
4594   SourceLocation ToStartLoc = Importer.Import(S->getStartLoc());
4595   SourceLocation ToEndLoc = Importer.Import(S->getEndLoc());
4596   return new (Importer.getToContext()) DeclStmt(ToDG, ToStartLoc, ToEndLoc);
4597 }
4598
4599 Stmt *ASTNodeImporter::VisitNullStmt(NullStmt *S) {
4600   SourceLocation ToSemiLoc = Importer.Import(S->getSemiLoc());
4601   return new (Importer.getToContext()) NullStmt(ToSemiLoc,
4602                                                 S->hasLeadingEmptyMacro());
4603 }
4604
4605 Stmt *ASTNodeImporter::VisitCompoundStmt(CompoundStmt *S) {
4606   SmallVector<Stmt *, 4> ToStmts(S->size());
4607   auto &_Importer = this->Importer;
4608   std::transform(S->body_begin(), S->body_end(), ToStmts.begin(),
4609     [&_Importer](Stmt *CS) -> Stmt * {
4610       return _Importer.Import(CS);
4611     });
4612   for (Stmt *ToS : ToStmts) {
4613     if (!ToS)
4614       return nullptr;
4615   }
4616   SourceLocation ToLBraceLoc = Importer.Import(S->getLBracLoc());
4617   SourceLocation ToRBraceLoc = Importer.Import(S->getRBracLoc());
4618   return new (Importer.getToContext()) CompoundStmt(Importer.getToContext(),
4619                                                     ToStmts,
4620                                                     ToLBraceLoc, ToRBraceLoc);
4621 }
4622
4623 Stmt *ASTNodeImporter::VisitCaseStmt(CaseStmt *S) {
4624   Expr *ToLHS = Importer.Import(S->getLHS());
4625   if (!ToLHS)
4626     return nullptr;
4627   Expr *ToRHS = Importer.Import(S->getRHS());
4628   if (!ToRHS && S->getRHS())
4629     return nullptr;
4630   SourceLocation ToCaseLoc = Importer.Import(S->getCaseLoc());
4631   SourceLocation ToEllipsisLoc = Importer.Import(S->getEllipsisLoc());
4632   SourceLocation ToColonLoc = Importer.Import(S->getColonLoc());
4633   return new (Importer.getToContext()) CaseStmt(ToLHS, ToRHS,
4634                                                 ToCaseLoc, ToEllipsisLoc,
4635                                                 ToColonLoc);
4636 }
4637
4638 Stmt *ASTNodeImporter::VisitDefaultStmt(DefaultStmt *S) {
4639   SourceLocation ToDefaultLoc = Importer.Import(S->getDefaultLoc());
4640   SourceLocation ToColonLoc = Importer.Import(S->getColonLoc());
4641   Stmt *ToSubStmt = Importer.Import(S->getSubStmt());
4642   if (!ToSubStmt && S->getSubStmt())
4643     return nullptr;
4644   return new (Importer.getToContext()) DefaultStmt(ToDefaultLoc, ToColonLoc,
4645                                                    ToSubStmt);
4646 }
4647
4648 Stmt *ASTNodeImporter::VisitLabelStmt(LabelStmt *S) {
4649   SourceLocation ToIdentLoc = Importer.Import(S->getIdentLoc());
4650   LabelDecl *ToLabelDecl =
4651     cast_or_null<LabelDecl>(Importer.Import(S->getDecl()));
4652   if (!ToLabelDecl && S->getDecl())
4653     return nullptr;
4654   Stmt *ToSubStmt = Importer.Import(S->getSubStmt());
4655   if (!ToSubStmt && S->getSubStmt())
4656     return nullptr;
4657   return new (Importer.getToContext()) LabelStmt(ToIdentLoc, ToLabelDecl,
4658                                                  ToSubStmt);
4659 }
4660
4661 Stmt *ASTNodeImporter::VisitAttributedStmt(AttributedStmt *S) {
4662   SourceLocation ToAttrLoc = Importer.Import(S->getAttrLoc());
4663   ArrayRef<const Attr*> FromAttrs(S->getAttrs());
4664   SmallVector<const Attr *, 1> ToAttrs(FromAttrs.size());
4665   ASTContext &_ToContext = Importer.getToContext();
4666   std::transform(FromAttrs.begin(), FromAttrs.end(), ToAttrs.begin(),
4667     [&_ToContext](const Attr *A) -> const Attr * {
4668       return A->clone(_ToContext);
4669     });
4670   for (const Attr *ToA : ToAttrs) {
4671     if (!ToA)
4672       return nullptr;
4673   }
4674   Stmt *ToSubStmt = Importer.Import(S->getSubStmt());
4675   if (!ToSubStmt && S->getSubStmt())
4676     return nullptr;
4677   return AttributedStmt::Create(Importer.getToContext(), ToAttrLoc,
4678                                 ToAttrs, ToSubStmt);
4679 }
4680
4681 Stmt *ASTNodeImporter::VisitIfStmt(IfStmt *S) {
4682   SourceLocation ToIfLoc = Importer.Import(S->getIfLoc());
4683   VarDecl *ToConditionVariable = nullptr;
4684   if (VarDecl *FromConditionVariable = S->getConditionVariable()) {
4685     ToConditionVariable =
4686       dyn_cast_or_null<VarDecl>(Importer.Import(FromConditionVariable));
4687     if (!ToConditionVariable)
4688       return nullptr;
4689   }
4690   Expr *ToCondition = Importer.Import(S->getCond());
4691   if (!ToCondition && S->getCond())
4692     return nullptr;
4693   Stmt *ToThenStmt = Importer.Import(S->getThen());
4694   if (!ToThenStmt && S->getThen())
4695     return nullptr;
4696   SourceLocation ToElseLoc = Importer.Import(S->getElseLoc());
4697   Stmt *ToElseStmt = Importer.Import(S->getElse());
4698   if (!ToElseStmt && S->getElse())
4699     return nullptr;
4700   return new (Importer.getToContext()) IfStmt(Importer.getToContext(),
4701                                               ToIfLoc, ToConditionVariable,
4702                                               ToCondition, ToThenStmt,
4703                                               ToElseLoc, ToElseStmt);
4704 }
4705
4706 Stmt *ASTNodeImporter::VisitSwitchStmt(SwitchStmt *S) {
4707   VarDecl *ToConditionVariable = nullptr;
4708   if (VarDecl *FromConditionVariable = S->getConditionVariable()) {
4709     ToConditionVariable =
4710       dyn_cast_or_null<VarDecl>(Importer.Import(FromConditionVariable));
4711     if (!ToConditionVariable)
4712       return nullptr;
4713   }
4714   Expr *ToCondition = Importer.Import(S->getCond());
4715   if (!ToCondition && S->getCond())
4716     return nullptr;
4717   SwitchStmt *ToStmt = new (Importer.getToContext()) SwitchStmt(
4718                          Importer.getToContext(), ToConditionVariable,
4719                          ToCondition);
4720   Stmt *ToBody = Importer.Import(S->getBody());
4721   if (!ToBody && S->getBody())
4722     return nullptr;
4723   ToStmt->setBody(ToBody);
4724   ToStmt->setSwitchLoc(Importer.Import(S->getSwitchLoc()));
4725   // Now we have to re-chain the cases.
4726   SwitchCase *LastChainedSwitchCase = nullptr;
4727   for (SwitchCase *SC = S->getSwitchCaseList(); SC != nullptr;
4728        SC = SC->getNextSwitchCase()) {
4729     SwitchCase *ToSC = dyn_cast_or_null<SwitchCase>(Importer.Import(SC));
4730     if (!ToSC)
4731       return nullptr;
4732     if (LastChainedSwitchCase)
4733       LastChainedSwitchCase->setNextSwitchCase(ToSC);
4734     else
4735       ToStmt->setSwitchCaseList(ToSC);
4736     LastChainedSwitchCase = ToSC;
4737   }
4738   return ToStmt;
4739 }
4740
4741 Stmt *ASTNodeImporter::VisitWhileStmt(WhileStmt *S) {
4742   VarDecl *ToConditionVariable = nullptr;
4743   if (VarDecl *FromConditionVariable = S->getConditionVariable()) {
4744     ToConditionVariable =
4745       dyn_cast_or_null<VarDecl>(Importer.Import(FromConditionVariable));
4746     if (!ToConditionVariable)
4747       return nullptr;
4748   }
4749   Expr *ToCondition = Importer.Import(S->getCond());
4750   if (!ToCondition && S->getCond())
4751     return nullptr;
4752   Stmt *ToBody = Importer.Import(S->getBody());
4753   if (!ToBody && S->getBody())
4754     return nullptr;
4755   SourceLocation ToWhileLoc = Importer.Import(S->getWhileLoc());
4756   return new (Importer.getToContext()) WhileStmt(Importer.getToContext(),
4757                                                  ToConditionVariable,
4758                                                  ToCondition, ToBody,
4759                                                  ToWhileLoc);
4760 }
4761
4762 Stmt *ASTNodeImporter::VisitDoStmt(DoStmt *S) {
4763   Stmt *ToBody = Importer.Import(S->getBody());
4764   if (!ToBody && S->getBody())
4765     return nullptr;
4766   Expr *ToCondition = Importer.Import(S->getCond());
4767   if (!ToCondition && S->getCond())
4768     return nullptr;
4769   SourceLocation ToDoLoc = Importer.Import(S->getDoLoc());
4770   SourceLocation ToWhileLoc = Importer.Import(S->getWhileLoc());
4771   SourceLocation ToRParenLoc = Importer.Import(S->getRParenLoc());
4772   return new (Importer.getToContext()) DoStmt(ToBody, ToCondition,
4773                                               ToDoLoc, ToWhileLoc,
4774                                               ToRParenLoc);
4775 }
4776
4777 Stmt *ASTNodeImporter::VisitForStmt(ForStmt *S) {
4778   Stmt *ToInit = Importer.Import(S->getInit());
4779   if (!ToInit && S->getInit())
4780     return nullptr;
4781   Expr *ToCondition = Importer.Import(S->getCond());
4782   if (!ToCondition && S->getCond())
4783     return nullptr;
4784   VarDecl *ToConditionVariable = nullptr;
4785   if (VarDecl *FromConditionVariable = S->getConditionVariable()) {
4786     ToConditionVariable =
4787       dyn_cast_or_null<VarDecl>(Importer.Import(FromConditionVariable));
4788     if (!ToConditionVariable)
4789       return nullptr;
4790   }
4791   Expr *ToInc = Importer.Import(S->getInc());
4792   if (!ToInc && S->getInc())
4793     return nullptr;
4794   Stmt *ToBody = Importer.Import(S->getBody());
4795   if (!ToBody && S->getBody())
4796     return nullptr;
4797   SourceLocation ToForLoc = Importer.Import(S->getForLoc());
4798   SourceLocation ToLParenLoc = Importer.Import(S->getLParenLoc());
4799   SourceLocation ToRParenLoc = Importer.Import(S->getRParenLoc());
4800   return new (Importer.getToContext()) ForStmt(Importer.getToContext(),
4801                                                ToInit, ToCondition,
4802                                                ToConditionVariable,
4803                                                ToInc, ToBody,
4804                                                ToForLoc, ToLParenLoc,
4805                                                ToRParenLoc);
4806 }
4807
4808 Stmt *ASTNodeImporter::VisitGotoStmt(GotoStmt *S) {
4809   LabelDecl *ToLabel = nullptr;
4810   if (LabelDecl *FromLabel = S->getLabel()) {
4811     ToLabel = dyn_cast_or_null<LabelDecl>(Importer.Import(FromLabel));
4812     if (!ToLabel)
4813       return nullptr;
4814   }
4815   SourceLocation ToGotoLoc = Importer.Import(S->getGotoLoc());
4816   SourceLocation ToLabelLoc = Importer.Import(S->getLabelLoc());
4817   return new (Importer.getToContext()) GotoStmt(ToLabel,
4818                                                 ToGotoLoc, ToLabelLoc);
4819 }
4820
4821 Stmt *ASTNodeImporter::VisitIndirectGotoStmt(IndirectGotoStmt *S) {
4822   SourceLocation ToGotoLoc = Importer.Import(S->getGotoLoc());
4823   SourceLocation ToStarLoc = Importer.Import(S->getStarLoc());
4824   Expr *ToTarget = Importer.Import(S->getTarget());
4825   if (!ToTarget && S->getTarget())
4826     return nullptr;
4827   return new (Importer.getToContext()) IndirectGotoStmt(ToGotoLoc, ToStarLoc,
4828                                                         ToTarget);
4829 }
4830
4831 Stmt *ASTNodeImporter::VisitContinueStmt(ContinueStmt *S) {
4832   SourceLocation ToContinueLoc = Importer.Import(S->getContinueLoc());
4833   return new (Importer.getToContext()) ContinueStmt(ToContinueLoc);
4834 }
4835
4836 Stmt *ASTNodeImporter::VisitBreakStmt(BreakStmt *S) {
4837   SourceLocation ToBreakLoc = Importer.Import(S->getBreakLoc());
4838   return new (Importer.getToContext()) BreakStmt(ToBreakLoc);
4839 }
4840
4841 Stmt *ASTNodeImporter::VisitReturnStmt(ReturnStmt *S) {
4842   SourceLocation ToRetLoc = Importer.Import(S->getReturnLoc());
4843   Expr *ToRetExpr = Importer.Import(S->getRetValue());
4844   if (!ToRetExpr && S->getRetValue())
4845     return nullptr;
4846   VarDecl *NRVOCandidate = const_cast<VarDecl*>(S->getNRVOCandidate());
4847   VarDecl *ToNRVOCandidate = cast_or_null<VarDecl>(Importer.Import(NRVOCandidate));
4848   if (!ToNRVOCandidate && NRVOCandidate)
4849     return nullptr;
4850   return new (Importer.getToContext()) ReturnStmt(ToRetLoc, ToRetExpr,
4851                                                   ToNRVOCandidate);
4852 }
4853
4854 Stmt *ASTNodeImporter::VisitCXXCatchStmt(CXXCatchStmt *S) {
4855   SourceLocation ToCatchLoc = Importer.Import(S->getCatchLoc());
4856   VarDecl *ToExceptionDecl = nullptr;
4857   if (VarDecl *FromExceptionDecl = S->getExceptionDecl()) {
4858     ToExceptionDecl =
4859       dyn_cast_or_null<VarDecl>(Importer.Import(FromExceptionDecl));
4860     if (!ToExceptionDecl)
4861       return nullptr;
4862   }
4863   Stmt *ToHandlerBlock = Importer.Import(S->getHandlerBlock());
4864   if (!ToHandlerBlock && S->getHandlerBlock())
4865     return nullptr;
4866   return new (Importer.getToContext()) CXXCatchStmt(ToCatchLoc,
4867                                                     ToExceptionDecl,
4868                                                     ToHandlerBlock);
4869 }
4870
4871 Stmt *ASTNodeImporter::VisitCXXTryStmt(CXXTryStmt *S) {
4872   SourceLocation ToTryLoc = Importer.Import(S->getTryLoc());
4873   Stmt *ToTryBlock = Importer.Import(S->getTryBlock());
4874   if (!ToTryBlock && S->getTryBlock())
4875     return nullptr;
4876   SmallVector<Stmt *, 1> ToHandlers(S->getNumHandlers());
4877   for (unsigned HI = 0, HE = S->getNumHandlers(); HI != HE; ++HI) {
4878     CXXCatchStmt *FromHandler = S->getHandler(HI);
4879     if (Stmt *ToHandler = Importer.Import(FromHandler))
4880       ToHandlers[HI] = ToHandler;
4881     else
4882       return nullptr;
4883   }
4884   return CXXTryStmt::Create(Importer.getToContext(), ToTryLoc, ToTryBlock,
4885                             ToHandlers);
4886 }
4887
4888 Stmt *ASTNodeImporter::VisitCXXForRangeStmt(CXXForRangeStmt *S) {
4889   DeclStmt *ToRange =
4890     dyn_cast_or_null<DeclStmt>(Importer.Import(S->getRangeStmt()));
4891   if (!ToRange && S->getRangeStmt())
4892     return nullptr;
4893   DeclStmt *ToBeginEnd =
4894     dyn_cast_or_null<DeclStmt>(Importer.Import(S->getBeginEndStmt()));
4895   if (!ToBeginEnd && S->getBeginEndStmt())
4896     return nullptr;
4897   Expr *ToCond = Importer.Import(S->getCond());
4898   if (!ToCond && S->getCond())
4899     return nullptr;
4900   Expr *ToInc = Importer.Import(S->getInc());
4901   if (!ToInc && S->getInc())
4902     return nullptr;
4903   DeclStmt *ToLoopVar =
4904     dyn_cast_or_null<DeclStmt>(Importer.Import(S->getLoopVarStmt()));
4905   if (!ToLoopVar && S->getLoopVarStmt())
4906     return nullptr;
4907   Stmt *ToBody = Importer.Import(S->getBody());
4908   if (!ToBody && S->getBody())
4909     return nullptr;
4910   SourceLocation ToForLoc = Importer.Import(S->getForLoc());
4911   SourceLocation ToColonLoc = Importer.Import(S->getColonLoc());
4912   SourceLocation ToRParenLoc = Importer.Import(S->getRParenLoc());
4913   return new (Importer.getToContext()) CXXForRangeStmt(ToRange, ToBeginEnd,
4914                                                        ToCond, ToInc,
4915                                                        ToLoopVar, ToBody,
4916                                                        ToForLoc, ToColonLoc,
4917                                                        ToRParenLoc);
4918 }
4919
4920 Stmt *ASTNodeImporter::VisitObjCForCollectionStmt(ObjCForCollectionStmt *S) {
4921   Stmt *ToElem = Importer.Import(S->getElement());
4922   if (!ToElem && S->getElement())
4923     return nullptr;
4924   Expr *ToCollect = Importer.Import(S->getCollection());
4925   if (!ToCollect && S->getCollection())
4926     return nullptr;
4927   Stmt *ToBody = Importer.Import(S->getBody());
4928   if (!ToBody && S->getBody())
4929     return nullptr;
4930   SourceLocation ToForLoc = Importer.Import(S->getForLoc());
4931   SourceLocation ToRParenLoc = Importer.Import(S->getRParenLoc());
4932   return new (Importer.getToContext()) ObjCForCollectionStmt(ToElem,
4933                                                              ToCollect,
4934                                                              ToBody, ToForLoc,
4935                                                              ToRParenLoc);
4936 }
4937
4938 Stmt *ASTNodeImporter::VisitObjCAtCatchStmt(ObjCAtCatchStmt *S) {
4939   SourceLocation ToAtCatchLoc = Importer.Import(S->getAtCatchLoc());
4940   SourceLocation ToRParenLoc = Importer.Import(S->getRParenLoc());
4941   VarDecl *ToExceptionDecl = nullptr;
4942   if (VarDecl *FromExceptionDecl = S->getCatchParamDecl()) {
4943     ToExceptionDecl =
4944       dyn_cast_or_null<VarDecl>(Importer.Import(FromExceptionDecl));
4945     if (!ToExceptionDecl)
4946       return nullptr;
4947   }
4948   Stmt *ToBody = Importer.Import(S->getCatchBody());
4949   if (!ToBody && S->getCatchBody())
4950     return nullptr;
4951   return new (Importer.getToContext()) ObjCAtCatchStmt(ToAtCatchLoc,
4952                                                        ToRParenLoc,
4953                                                        ToExceptionDecl,
4954                                                        ToBody);
4955 }
4956
4957 Stmt *ASTNodeImporter::VisitObjCAtFinallyStmt(ObjCAtFinallyStmt *S) {
4958   SourceLocation ToAtFinallyLoc = Importer.Import(S->getAtFinallyLoc());
4959   Stmt *ToAtFinallyStmt = Importer.Import(S->getFinallyBody());
4960   if (!ToAtFinallyStmt && S->getFinallyBody())
4961     return nullptr;
4962   return new (Importer.getToContext()) ObjCAtFinallyStmt(ToAtFinallyLoc,
4963                                                          ToAtFinallyStmt);
4964 }
4965
4966 Stmt *ASTNodeImporter::VisitObjCAtTryStmt(ObjCAtTryStmt *S) {
4967   SourceLocation ToAtTryLoc = Importer.Import(S->getAtTryLoc());
4968   Stmt *ToAtTryStmt = Importer.Import(S->getTryBody());
4969   if (!ToAtTryStmt && S->getTryBody())
4970     return nullptr;
4971   SmallVector<Stmt *, 1> ToCatchStmts(S->getNumCatchStmts());
4972   for (unsigned CI = 0, CE = S->getNumCatchStmts(); CI != CE; ++CI) {
4973     ObjCAtCatchStmt *FromCatchStmt = S->getCatchStmt(CI);
4974     if (Stmt *ToCatchStmt = Importer.Import(FromCatchStmt))
4975       ToCatchStmts[CI] = ToCatchStmt;
4976     else
4977       return nullptr;
4978   }
4979   Stmt *ToAtFinallyStmt = Importer.Import(S->getFinallyStmt());
4980   if (!ToAtFinallyStmt && S->getFinallyStmt())
4981     return nullptr;
4982   return ObjCAtTryStmt::Create(Importer.getToContext(),
4983                                ToAtTryLoc, ToAtTryStmt,
4984                                ToCatchStmts.begin(), ToCatchStmts.size(),
4985                                ToAtFinallyStmt);
4986 }
4987
4988 Stmt *ASTNodeImporter::VisitObjCAtSynchronizedStmt
4989   (ObjCAtSynchronizedStmt *S) {
4990   SourceLocation ToAtSynchronizedLoc =
4991     Importer.Import(S->getAtSynchronizedLoc());
4992   Expr *ToSynchExpr = Importer.Import(S->getSynchExpr());
4993   if (!ToSynchExpr && S->getSynchExpr())
4994     return nullptr;
4995   Stmt *ToSynchBody = Importer.Import(S->getSynchBody());
4996   if (!ToSynchBody && S->getSynchBody())
4997     return nullptr;
4998   return new (Importer.getToContext()) ObjCAtSynchronizedStmt(
4999     ToAtSynchronizedLoc, ToSynchExpr, ToSynchBody);
5000 }
5001
5002 Stmt *ASTNodeImporter::VisitObjCAtThrowStmt(ObjCAtThrowStmt *S) {
5003   SourceLocation ToAtThrowLoc = Importer.Import(S->getThrowLoc());
5004   Expr *ToThrow = Importer.Import(S->getThrowExpr());
5005   if (!ToThrow && S->getThrowExpr())
5006     return nullptr;
5007   return new (Importer.getToContext()) ObjCAtThrowStmt(ToAtThrowLoc, ToThrow);
5008 }
5009
5010 Stmt *ASTNodeImporter::VisitObjCAutoreleasePoolStmt
5011   (ObjCAutoreleasePoolStmt *S) {
5012   SourceLocation ToAtLoc = Importer.Import(S->getAtLoc());
5013   Stmt *ToSubStmt = Importer.Import(S->getSubStmt());
5014   if (!ToSubStmt && S->getSubStmt())
5015     return nullptr;
5016   return new (Importer.getToContext()) ObjCAutoreleasePoolStmt(ToAtLoc,
5017                                                                ToSubStmt);
5018 }
5019
5020 //----------------------------------------------------------------------------
5021 // Import Expressions
5022 //----------------------------------------------------------------------------
5023 Expr *ASTNodeImporter::VisitExpr(Expr *E) {
5024   Importer.FromDiag(E->getLocStart(), diag::err_unsupported_ast_node)
5025     << E->getStmtClassName();
5026   return nullptr;
5027 }
5028
5029 Expr *ASTNodeImporter::VisitDeclRefExpr(DeclRefExpr *E) {
5030   ValueDecl *ToD = cast_or_null<ValueDecl>(Importer.Import(E->getDecl()));
5031   if (!ToD)
5032     return nullptr;
5033
5034   NamedDecl *FoundD = nullptr;
5035   if (E->getDecl() != E->getFoundDecl()) {
5036     FoundD = cast_or_null<NamedDecl>(Importer.Import(E->getFoundDecl()));
5037     if (!FoundD)
5038       return nullptr;
5039   }
5040
5041   QualType T = Importer.Import(E->getType());
5042   if (T.isNull())
5043     return nullptr;
5044
5045   DeclRefExpr *DRE = DeclRefExpr::Create(Importer.getToContext(),
5046                                          Importer.Import(E->getQualifierLoc()),
5047                                    Importer.Import(E->getTemplateKeywordLoc()),
5048                                          ToD,
5049                                         E->refersToEnclosingVariableOrCapture(),
5050                                          Importer.Import(E->getLocation()),
5051                                          T, E->getValueKind(),
5052                                          FoundD,
5053                                          /*FIXME:TemplateArgs=*/nullptr);
5054   if (E->hadMultipleCandidates())
5055     DRE->setHadMultipleCandidates(true);
5056   return DRE;
5057 }
5058
5059 Expr *ASTNodeImporter::VisitIntegerLiteral(IntegerLiteral *E) {
5060   QualType T = Importer.Import(E->getType());
5061   if (T.isNull())
5062     return nullptr;
5063
5064   return IntegerLiteral::Create(Importer.getToContext(),
5065                                 E->getValue(), T,
5066                                 Importer.Import(E->getLocation()));
5067 }
5068
5069 Expr *ASTNodeImporter::VisitCharacterLiteral(CharacterLiteral *E) {
5070   QualType T = Importer.Import(E->getType());
5071   if (T.isNull())
5072     return nullptr;
5073
5074   return new (Importer.getToContext()) CharacterLiteral(E->getValue(),
5075                                                         E->getKind(), T,
5076                                           Importer.Import(E->getLocation()));
5077 }
5078
5079 Expr *ASTNodeImporter::VisitParenExpr(ParenExpr *E) {
5080   Expr *SubExpr = Importer.Import(E->getSubExpr());
5081   if (!SubExpr)
5082     return nullptr;
5083
5084   return new (Importer.getToContext())
5085                                   ParenExpr(Importer.Import(E->getLParen()),
5086                                             Importer.Import(E->getRParen()),
5087                                             SubExpr);
5088 }
5089
5090 Expr *ASTNodeImporter::VisitUnaryOperator(UnaryOperator *E) {
5091   QualType T = Importer.Import(E->getType());
5092   if (T.isNull())
5093     return nullptr;
5094
5095   Expr *SubExpr = Importer.Import(E->getSubExpr());
5096   if (!SubExpr)
5097     return nullptr;
5098
5099   return new (Importer.getToContext()) UnaryOperator(SubExpr, E->getOpcode(),
5100                                                      T, E->getValueKind(),
5101                                                      E->getObjectKind(),
5102                                          Importer.Import(E->getOperatorLoc()));
5103 }
5104
5105 Expr *ASTNodeImporter::VisitUnaryExprOrTypeTraitExpr(
5106                                             UnaryExprOrTypeTraitExpr *E) {
5107   QualType ResultType = Importer.Import(E->getType());
5108
5109   if (E->isArgumentType()) {
5110     TypeSourceInfo *TInfo = Importer.Import(E->getArgumentTypeInfo());
5111     if (!TInfo)
5112       return nullptr;
5113
5114     return new (Importer.getToContext()) UnaryExprOrTypeTraitExpr(E->getKind(),
5115                                            TInfo, ResultType,
5116                                            Importer.Import(E->getOperatorLoc()),
5117                                            Importer.Import(E->getRParenLoc()));
5118   }
5119
5120   Expr *SubExpr = Importer.Import(E->getArgumentExpr());
5121   if (!SubExpr)
5122     return nullptr;
5123
5124   return new (Importer.getToContext()) UnaryExprOrTypeTraitExpr(E->getKind(),
5125                                           SubExpr, ResultType,
5126                                           Importer.Import(E->getOperatorLoc()),
5127                                           Importer.Import(E->getRParenLoc()));
5128 }
5129
5130 Expr *ASTNodeImporter::VisitBinaryOperator(BinaryOperator *E) {
5131   QualType T = Importer.Import(E->getType());
5132   if (T.isNull())
5133     return nullptr;
5134
5135   Expr *LHS = Importer.Import(E->getLHS());
5136   if (!LHS)
5137     return nullptr;
5138
5139   Expr *RHS = Importer.Import(E->getRHS());
5140   if (!RHS)
5141     return nullptr;
5142
5143   return new (Importer.getToContext()) BinaryOperator(LHS, RHS, E->getOpcode(),
5144                                                       T, E->getValueKind(),
5145                                                       E->getObjectKind(),
5146                                            Importer.Import(E->getOperatorLoc()),
5147                                                       E->isFPContractable());
5148 }
5149
5150 Expr *ASTNodeImporter::VisitCompoundAssignOperator(CompoundAssignOperator *E) {
5151   QualType T = Importer.Import(E->getType());
5152   if (T.isNull())
5153     return nullptr;
5154
5155   QualType CompLHSType = Importer.Import(E->getComputationLHSType());
5156   if (CompLHSType.isNull())
5157     return nullptr;
5158
5159   QualType CompResultType = Importer.Import(E->getComputationResultType());
5160   if (CompResultType.isNull())
5161     return nullptr;
5162
5163   Expr *LHS = Importer.Import(E->getLHS());
5164   if (!LHS)
5165     return nullptr;
5166
5167   Expr *RHS = Importer.Import(E->getRHS());
5168   if (!RHS)
5169     return nullptr;
5170
5171   return new (Importer.getToContext())
5172                         CompoundAssignOperator(LHS, RHS, E->getOpcode(),
5173                                                T, E->getValueKind(),
5174                                                E->getObjectKind(),
5175                                                CompLHSType, CompResultType,
5176                                            Importer.Import(E->getOperatorLoc()),
5177                                                E->isFPContractable());
5178 }
5179
5180 static bool ImportCastPath(CastExpr *E, CXXCastPath &Path) {
5181   if (E->path_empty()) return false;
5182
5183   // TODO: import cast paths
5184   return true;
5185 }
5186
5187 Expr *ASTNodeImporter::VisitImplicitCastExpr(ImplicitCastExpr *E) {
5188   QualType T = Importer.Import(E->getType());
5189   if (T.isNull())
5190     return nullptr;
5191
5192   Expr *SubExpr = Importer.Import(E->getSubExpr());
5193   if (!SubExpr)
5194     return nullptr;
5195
5196   CXXCastPath BasePath;
5197   if (ImportCastPath(E, BasePath))
5198     return nullptr;
5199
5200   return ImplicitCastExpr::Create(Importer.getToContext(), T, E->getCastKind(),
5201                                   SubExpr, &BasePath, E->getValueKind());
5202 }
5203
5204 Expr *ASTNodeImporter::VisitCStyleCastExpr(CStyleCastExpr *E) {
5205   QualType T = Importer.Import(E->getType());
5206   if (T.isNull())
5207     return nullptr;
5208
5209   Expr *SubExpr = Importer.Import(E->getSubExpr());
5210   if (!SubExpr)
5211     return nullptr;
5212
5213   TypeSourceInfo *TInfo = Importer.Import(E->getTypeInfoAsWritten());
5214   if (!TInfo && E->getTypeInfoAsWritten())
5215     return nullptr;
5216
5217   CXXCastPath BasePath;
5218   if (ImportCastPath(E, BasePath))
5219     return nullptr;
5220
5221   return CStyleCastExpr::Create(Importer.getToContext(), T,
5222                                 E->getValueKind(), E->getCastKind(),
5223                                 SubExpr, &BasePath, TInfo,
5224                                 Importer.Import(E->getLParenLoc()),
5225                                 Importer.Import(E->getRParenLoc()));
5226 }
5227
5228 Expr *ASTNodeImporter::VisitCXXConstructExpr(CXXConstructExpr *E) {
5229   QualType T = Importer.Import(E->getType());
5230   if (T.isNull())
5231     return nullptr;
5232
5233   CXXConstructorDecl *ToCCD =
5234     dyn_cast<CXXConstructorDecl>(Importer.Import(E->getConstructor()));
5235   if (!ToCCD && E->getConstructor())
5236     return nullptr;
5237
5238   size_t NumArgs = E->getNumArgs();
5239   SmallVector<Expr *, 1> ToArgs(NumArgs);
5240   ASTImporter &_Importer = Importer;
5241   std::transform(E->arg_begin(), E->arg_end(), ToArgs.begin(),
5242     [&_Importer](Expr *AE) -> Expr * {
5243       return _Importer.Import(AE);
5244     });
5245   for (Expr *ToA : ToArgs) {
5246     if (!ToA)
5247       return nullptr;
5248   }
5249
5250   return CXXConstructExpr::Create(Importer.getToContext(), T,
5251                                   Importer.Import(E->getLocation()),
5252                                   ToCCD, E->isElidable(),
5253                                   ToArgs, E->hadMultipleCandidates(),
5254                                   E->isListInitialization(),
5255                                   E->isStdInitListInitialization(),
5256                                   E->requiresZeroInitialization(),
5257                                   E->getConstructionKind(),
5258                                   Importer.Import(E->getParenOrBraceRange()));
5259 }
5260
5261 Expr *ASTNodeImporter::VisitMemberExpr(MemberExpr *E) {
5262   QualType T = Importer.Import(E->getType());
5263   if (T.isNull())
5264     return nullptr;
5265
5266   Expr *ToBase = Importer.Import(E->getBase());
5267   if (!ToBase && E->getBase())
5268     return nullptr;
5269
5270   ValueDecl *ToMember = dyn_cast<ValueDecl>(Importer.Import(E->getMemberDecl()));
5271   if (!ToMember && E->getMemberDecl())
5272     return nullptr;
5273
5274   DeclAccessPair ToFoundDecl = DeclAccessPair::make(
5275     dyn_cast<NamedDecl>(Importer.Import(E->getFoundDecl().getDecl())),
5276     E->getFoundDecl().getAccess());
5277
5278   DeclarationNameInfo ToMemberNameInfo(
5279     Importer.Import(E->getMemberNameInfo().getName()),
5280     Importer.Import(E->getMemberNameInfo().getLoc()));
5281
5282   if (E->hasExplicitTemplateArgs()) {
5283     return nullptr; // FIXME: handle template arguments
5284   }
5285
5286   return MemberExpr::Create(Importer.getToContext(), ToBase,
5287                             E->isArrow(),
5288                             Importer.Import(E->getOperatorLoc()),
5289                             Importer.Import(E->getQualifierLoc()),
5290                             Importer.Import(E->getTemplateKeywordLoc()),
5291                             ToMember, ToFoundDecl, ToMemberNameInfo,
5292                             nullptr, T, E->getValueKind(),
5293                             E->getObjectKind());
5294 }
5295
5296 Expr *ASTNodeImporter::VisitCallExpr(CallExpr *E) {
5297   QualType T = Importer.Import(E->getType());
5298   if (T.isNull())
5299     return nullptr;
5300
5301   Expr *ToCallee = Importer.Import(E->getCallee());
5302   if (!ToCallee && E->getCallee())
5303     return nullptr;
5304
5305   unsigned NumArgs = E->getNumArgs();
5306
5307   llvm::SmallVector<Expr *, 2> ToArgs(NumArgs);
5308
5309   for (unsigned ai = 0, ae = NumArgs; ai != ae; ++ai) {
5310     Expr *FromArg = E->getArg(ai);
5311     Expr *ToArg = Importer.Import(FromArg);
5312     if (!ToArg)
5313       return nullptr;
5314     ToArgs[ai] = ToArg;
5315   }
5316
5317   Expr **ToArgs_Copied = new (Importer.getToContext())
5318     Expr*[NumArgs];
5319
5320   for (unsigned ai = 0, ae = NumArgs; ai != ae; ++ai)
5321     ToArgs_Copied[ai] = ToArgs[ai];
5322
5323   return new (Importer.getToContext())
5324     CallExpr(Importer.getToContext(), ToCallee,
5325              ArrayRef<Expr*>(ToArgs_Copied, NumArgs), T, E->getValueKind(),
5326              Importer.Import(E->getRParenLoc()));
5327 }
5328
5329 ASTImporter::ASTImporter(ASTContext &ToContext, FileManager &ToFileManager,
5330                          ASTContext &FromContext, FileManager &FromFileManager,
5331                          bool MinimalImport)
5332   : ToContext(ToContext), FromContext(FromContext),
5333     ToFileManager(ToFileManager), FromFileManager(FromFileManager),
5334     Minimal(MinimalImport), LastDiagFromFrom(false)
5335 {
5336   ImportedDecls[FromContext.getTranslationUnitDecl()]
5337     = ToContext.getTranslationUnitDecl();
5338 }
5339
5340 ASTImporter::~ASTImporter() { }
5341
5342 QualType ASTImporter::Import(QualType FromT) {
5343   if (FromT.isNull())
5344     return QualType();
5345
5346   const Type *fromTy = FromT.getTypePtr();
5347
5348   // Check whether we've already imported this type.
5349   llvm::DenseMap<const Type *, const Type *>::iterator Pos
5350     = ImportedTypes.find(fromTy);
5351   if (Pos != ImportedTypes.end())
5352     return ToContext.getQualifiedType(Pos->second, FromT.getLocalQualifiers());
5353
5354   // Import the type
5355   ASTNodeImporter Importer(*this);
5356   QualType ToT = Importer.Visit(fromTy);
5357   if (ToT.isNull())
5358     return ToT;
5359
5360   // Record the imported type.
5361   ImportedTypes[fromTy] = ToT.getTypePtr();
5362
5363   return ToContext.getQualifiedType(ToT, FromT.getLocalQualifiers());
5364 }
5365
5366 TypeSourceInfo *ASTImporter::Import(TypeSourceInfo *FromTSI) {
5367   if (!FromTSI)
5368     return FromTSI;
5369
5370   // FIXME: For now we just create a "trivial" type source info based
5371   // on the type and a single location. Implement a real version of this.
5372   QualType T = Import(FromTSI->getType());
5373   if (T.isNull())
5374     return nullptr;
5375
5376   return ToContext.getTrivialTypeSourceInfo(T,
5377            Import(FromTSI->getTypeLoc().getLocStart()));
5378 }
5379
5380 Decl *ASTImporter::GetAlreadyImportedOrNull(Decl *FromD) {
5381   llvm::DenseMap<Decl *, Decl *>::iterator Pos = ImportedDecls.find(FromD);
5382   if (Pos != ImportedDecls.end()) {
5383     Decl *ToD = Pos->second;
5384     ASTNodeImporter(*this).ImportDefinitionIfNeeded(FromD, ToD);
5385     return ToD;
5386   } else {
5387     return nullptr;
5388   }
5389 }
5390
5391 Decl *ASTImporter::Import(Decl *FromD) {
5392   if (!FromD)
5393     return nullptr;
5394
5395   ASTNodeImporter Importer(*this);
5396
5397   // Check whether we've already imported this declaration.
5398   llvm::DenseMap<Decl *, Decl *>::iterator Pos = ImportedDecls.find(FromD);
5399   if (Pos != ImportedDecls.end()) {
5400     Decl *ToD = Pos->second;
5401     Importer.ImportDefinitionIfNeeded(FromD, ToD);
5402     return ToD;
5403   }
5404
5405   // Import the type
5406   Decl *ToD = Importer.Visit(FromD);
5407   if (!ToD)
5408     return nullptr;
5409
5410   // Record the imported declaration.
5411   ImportedDecls[FromD] = ToD;
5412
5413   if (TagDecl *FromTag = dyn_cast<TagDecl>(FromD)) {
5414     // Keep track of anonymous tags that have an associated typedef.
5415     if (FromTag->getTypedefNameForAnonDecl())
5416       AnonTagsWithPendingTypedefs.push_back(FromTag);
5417   } else if (TypedefNameDecl *FromTypedef = dyn_cast<TypedefNameDecl>(FromD)) {
5418     // When we've finished transforming a typedef, see whether it was the
5419     // typedef for an anonymous tag.
5420     for (SmallVectorImpl<TagDecl *>::iterator
5421                FromTag = AnonTagsWithPendingTypedefs.begin(),
5422             FromTagEnd = AnonTagsWithPendingTypedefs.end();
5423          FromTag != FromTagEnd; ++FromTag) {
5424       if ((*FromTag)->getTypedefNameForAnonDecl() == FromTypedef) {
5425         if (TagDecl *ToTag = cast_or_null<TagDecl>(Import(*FromTag))) {
5426           // We found the typedef for an anonymous tag; link them.
5427           ToTag->setTypedefNameForAnonDecl(cast<TypedefNameDecl>(ToD));
5428           AnonTagsWithPendingTypedefs.erase(FromTag);
5429           break;
5430         }
5431       }
5432     }
5433   }
5434
5435   return ToD;
5436 }
5437
5438 DeclContext *ASTImporter::ImportContext(DeclContext *FromDC) {
5439   if (!FromDC)
5440     return FromDC;
5441
5442   DeclContext *ToDC = cast_or_null<DeclContext>(Import(cast<Decl>(FromDC)));
5443   if (!ToDC)
5444     return nullptr;
5445
5446   // When we're using a record/enum/Objective-C class/protocol as a context, we
5447   // need it to have a definition.
5448   if (RecordDecl *ToRecord = dyn_cast<RecordDecl>(ToDC)) {
5449     RecordDecl *FromRecord = cast<RecordDecl>(FromDC);
5450     if (ToRecord->isCompleteDefinition()) {
5451       // Do nothing.
5452     } else if (FromRecord->isCompleteDefinition()) {
5453       ASTNodeImporter(*this).ImportDefinition(FromRecord, ToRecord,
5454                                               ASTNodeImporter::IDK_Basic);
5455     } else {
5456       CompleteDecl(ToRecord);
5457     }
5458   } else if (EnumDecl *ToEnum = dyn_cast<EnumDecl>(ToDC)) {
5459     EnumDecl *FromEnum = cast<EnumDecl>(FromDC);
5460     if (ToEnum->isCompleteDefinition()) {
5461       // Do nothing.
5462     } else if (FromEnum->isCompleteDefinition()) {
5463       ASTNodeImporter(*this).ImportDefinition(FromEnum, ToEnum,
5464                                               ASTNodeImporter::IDK_Basic);
5465     } else {
5466       CompleteDecl(ToEnum);
5467     }
5468   } else if (ObjCInterfaceDecl *ToClass = dyn_cast<ObjCInterfaceDecl>(ToDC)) {
5469     ObjCInterfaceDecl *FromClass = cast<ObjCInterfaceDecl>(FromDC);
5470     if (ToClass->getDefinition()) {
5471       // Do nothing.
5472     } else if (ObjCInterfaceDecl *FromDef = FromClass->getDefinition()) {
5473       ASTNodeImporter(*this).ImportDefinition(FromDef, ToClass,
5474                                               ASTNodeImporter::IDK_Basic);
5475     } else {
5476       CompleteDecl(ToClass);
5477     }
5478   } else if (ObjCProtocolDecl *ToProto = dyn_cast<ObjCProtocolDecl>(ToDC)) {
5479     ObjCProtocolDecl *FromProto = cast<ObjCProtocolDecl>(FromDC);
5480     if (ToProto->getDefinition()) {
5481       // Do nothing.
5482     } else if (ObjCProtocolDecl *FromDef = FromProto->getDefinition()) {
5483       ASTNodeImporter(*this).ImportDefinition(FromDef, ToProto,
5484                                               ASTNodeImporter::IDK_Basic);
5485     } else {
5486       CompleteDecl(ToProto);
5487     }
5488   }
5489
5490   return ToDC;
5491 }
5492
5493 Expr *ASTImporter::Import(Expr *FromE) {
5494   if (!FromE)
5495     return nullptr;
5496
5497   return cast_or_null<Expr>(Import(cast<Stmt>(FromE)));
5498 }
5499
5500 Stmt *ASTImporter::Import(Stmt *FromS) {
5501   if (!FromS)
5502     return nullptr;
5503
5504   // Check whether we've already imported this declaration.
5505   llvm::DenseMap<Stmt *, Stmt *>::iterator Pos = ImportedStmts.find(FromS);
5506   if (Pos != ImportedStmts.end())
5507     return Pos->second;
5508
5509   // Import the type
5510   ASTNodeImporter Importer(*this);
5511   Stmt *ToS = Importer.Visit(FromS);
5512   if (!ToS)
5513     return nullptr;
5514
5515   // Record the imported declaration.
5516   ImportedStmts[FromS] = ToS;
5517   return ToS;
5518 }
5519
5520 NestedNameSpecifier *ASTImporter::Import(NestedNameSpecifier *FromNNS) {
5521   if (!FromNNS)
5522     return nullptr;
5523
5524   NestedNameSpecifier *prefix = Import(FromNNS->getPrefix());
5525
5526   switch (FromNNS->getKind()) {
5527   case NestedNameSpecifier::Identifier:
5528     if (IdentifierInfo *II = Import(FromNNS->getAsIdentifier())) {
5529       return NestedNameSpecifier::Create(ToContext, prefix, II);
5530     }
5531     return nullptr;
5532
5533   case NestedNameSpecifier::Namespace:
5534     if (NamespaceDecl *NS =
5535           cast<NamespaceDecl>(Import(FromNNS->getAsNamespace()))) {
5536       return NestedNameSpecifier::Create(ToContext, prefix, NS);
5537     }
5538     return nullptr;
5539
5540   case NestedNameSpecifier::NamespaceAlias:
5541     if (NamespaceAliasDecl *NSAD =
5542           cast<NamespaceAliasDecl>(Import(FromNNS->getAsNamespaceAlias()))) {
5543       return NestedNameSpecifier::Create(ToContext, prefix, NSAD);
5544     }
5545     return nullptr;
5546
5547   case NestedNameSpecifier::Global:
5548     return NestedNameSpecifier::GlobalSpecifier(ToContext);
5549
5550   case NestedNameSpecifier::Super:
5551     if (CXXRecordDecl *RD =
5552             cast<CXXRecordDecl>(Import(FromNNS->getAsRecordDecl()))) {
5553       return NestedNameSpecifier::SuperSpecifier(ToContext, RD);
5554     }
5555     return nullptr;
5556
5557   case NestedNameSpecifier::TypeSpec:
5558   case NestedNameSpecifier::TypeSpecWithTemplate: {
5559       QualType T = Import(QualType(FromNNS->getAsType(), 0u));
5560       if (!T.isNull()) {
5561         bool bTemplate = FromNNS->getKind() ==
5562                          NestedNameSpecifier::TypeSpecWithTemplate;
5563         return NestedNameSpecifier::Create(ToContext, prefix,
5564                                            bTemplate, T.getTypePtr());
5565       }
5566     }
5567       return nullptr;
5568   }
5569
5570   llvm_unreachable("Invalid nested name specifier kind");
5571 }
5572
5573 NestedNameSpecifierLoc ASTImporter::Import(NestedNameSpecifierLoc FromNNS) {
5574   // FIXME: Implement!
5575   return NestedNameSpecifierLoc();
5576 }
5577
5578 TemplateName ASTImporter::Import(TemplateName From) {
5579   switch (From.getKind()) {
5580   case TemplateName::Template:
5581     if (TemplateDecl *ToTemplate
5582                 = cast_or_null<TemplateDecl>(Import(From.getAsTemplateDecl())))
5583       return TemplateName(ToTemplate);
5584
5585     return TemplateName();
5586
5587   case TemplateName::OverloadedTemplate: {
5588     OverloadedTemplateStorage *FromStorage = From.getAsOverloadedTemplate();
5589     UnresolvedSet<2> ToTemplates;
5590     for (OverloadedTemplateStorage::iterator I = FromStorage->begin(),
5591                                              E = FromStorage->end();
5592          I != E; ++I) {
5593       if (NamedDecl *To = cast_or_null<NamedDecl>(Import(*I)))
5594         ToTemplates.addDecl(To);
5595       else
5596         return TemplateName();
5597     }
5598     return ToContext.getOverloadedTemplateName(ToTemplates.begin(),
5599                                                ToTemplates.end());
5600   }
5601
5602   case TemplateName::QualifiedTemplate: {
5603     QualifiedTemplateName *QTN = From.getAsQualifiedTemplateName();
5604     NestedNameSpecifier *Qualifier = Import(QTN->getQualifier());
5605     if (!Qualifier)
5606       return TemplateName();
5607
5608     if (TemplateDecl *ToTemplate
5609         = cast_or_null<TemplateDecl>(Import(From.getAsTemplateDecl())))
5610       return ToContext.getQualifiedTemplateName(Qualifier,
5611                                                 QTN->hasTemplateKeyword(),
5612                                                 ToTemplate);
5613
5614     return TemplateName();
5615   }
5616
5617   case TemplateName::DependentTemplate: {
5618     DependentTemplateName *DTN = From.getAsDependentTemplateName();
5619     NestedNameSpecifier *Qualifier = Import(DTN->getQualifier());
5620     if (!Qualifier)
5621       return TemplateName();
5622
5623     if (DTN->isIdentifier()) {
5624       return ToContext.getDependentTemplateName(Qualifier,
5625                                                 Import(DTN->getIdentifier()));
5626     }
5627
5628     return ToContext.getDependentTemplateName(Qualifier, DTN->getOperator());
5629   }
5630
5631   case TemplateName::SubstTemplateTemplateParm: {
5632     SubstTemplateTemplateParmStorage *subst
5633       = From.getAsSubstTemplateTemplateParm();
5634     TemplateTemplateParmDecl *param
5635       = cast_or_null<TemplateTemplateParmDecl>(Import(subst->getParameter()));
5636     if (!param)
5637       return TemplateName();
5638
5639     TemplateName replacement = Import(subst->getReplacement());
5640     if (replacement.isNull()) return TemplateName();
5641
5642     return ToContext.getSubstTemplateTemplateParm(param, replacement);
5643   }
5644
5645   case TemplateName::SubstTemplateTemplateParmPack: {
5646     SubstTemplateTemplateParmPackStorage *SubstPack
5647       = From.getAsSubstTemplateTemplateParmPack();
5648     TemplateTemplateParmDecl *Param
5649       = cast_or_null<TemplateTemplateParmDecl>(
5650                                         Import(SubstPack->getParameterPack()));
5651     if (!Param)
5652       return TemplateName();
5653
5654     ASTNodeImporter Importer(*this);
5655     TemplateArgument ArgPack
5656       = Importer.ImportTemplateArgument(SubstPack->getArgumentPack());
5657     if (ArgPack.isNull())
5658       return TemplateName();
5659
5660     return ToContext.getSubstTemplateTemplateParmPack(Param, ArgPack);
5661   }
5662   }
5663
5664   llvm_unreachable("Invalid template name kind");
5665 }
5666
5667 SourceLocation ASTImporter::Import(SourceLocation FromLoc) {
5668   if (FromLoc.isInvalid())
5669     return SourceLocation();
5670
5671   SourceManager &FromSM = FromContext.getSourceManager();
5672
5673   // For now, map everything down to its spelling location, so that we
5674   // don't have to import macro expansions.
5675   // FIXME: Import macro expansions!
5676   FromLoc = FromSM.getSpellingLoc(FromLoc);
5677   std::pair<FileID, unsigned> Decomposed = FromSM.getDecomposedLoc(FromLoc);
5678   SourceManager &ToSM = ToContext.getSourceManager();
5679   FileID ToFileID = Import(Decomposed.first);
5680   if (ToFileID.isInvalid())
5681     return SourceLocation();
5682   SourceLocation ret = ToSM.getLocForStartOfFile(ToFileID)
5683                            .getLocWithOffset(Decomposed.second);
5684   return ret;
5685 }
5686
5687 SourceRange ASTImporter::Import(SourceRange FromRange) {
5688   return SourceRange(Import(FromRange.getBegin()), Import(FromRange.getEnd()));
5689 }
5690
5691 FileID ASTImporter::Import(FileID FromID) {
5692   llvm::DenseMap<FileID, FileID>::iterator Pos
5693     = ImportedFileIDs.find(FromID);
5694   if (Pos != ImportedFileIDs.end())
5695     return Pos->second;
5696
5697   SourceManager &FromSM = FromContext.getSourceManager();
5698   SourceManager &ToSM = ToContext.getSourceManager();
5699   const SrcMgr::SLocEntry &FromSLoc = FromSM.getSLocEntry(FromID);
5700   assert(FromSLoc.isFile() && "Cannot handle macro expansions yet");
5701
5702   // Include location of this file.
5703   SourceLocation ToIncludeLoc = Import(FromSLoc.getFile().getIncludeLoc());
5704
5705   // Map the FileID for to the "to" source manager.
5706   FileID ToID;
5707   const SrcMgr::ContentCache *Cache = FromSLoc.getFile().getContentCache();
5708   if (Cache->OrigEntry && Cache->OrigEntry->getDir()) {
5709     // FIXME: We probably want to use getVirtualFile(), so we don't hit the
5710     // disk again
5711     // FIXME: We definitely want to re-use the existing MemoryBuffer, rather
5712     // than mmap the files several times.
5713     const FileEntry *Entry = ToFileManager.getFile(Cache->OrigEntry->getName());
5714     if (!Entry)
5715       return FileID();
5716     ToID = ToSM.createFileID(Entry, ToIncludeLoc,
5717                              FromSLoc.getFile().getFileCharacteristic());
5718   } else {
5719     // FIXME: We want to re-use the existing MemoryBuffer!
5720     const llvm::MemoryBuffer *
5721         FromBuf = Cache->getBuffer(FromContext.getDiagnostics(), FromSM);
5722     std::unique_ptr<llvm::MemoryBuffer> ToBuf
5723       = llvm::MemoryBuffer::getMemBufferCopy(FromBuf->getBuffer(),
5724                                              FromBuf->getBufferIdentifier());
5725     ToID = ToSM.createFileID(std::move(ToBuf),
5726                              FromSLoc.getFile().getFileCharacteristic());
5727   }
5728
5729
5730   ImportedFileIDs[FromID] = ToID;
5731   return ToID;
5732 }
5733
5734 void ASTImporter::ImportDefinition(Decl *From) {
5735   Decl *To = Import(From);
5736   if (!To)
5737     return;
5738
5739   if (DeclContext *FromDC = cast<DeclContext>(From)) {
5740     ASTNodeImporter Importer(*this);
5741
5742     if (RecordDecl *ToRecord = dyn_cast<RecordDecl>(To)) {
5743       if (!ToRecord->getDefinition()) {
5744         Importer.ImportDefinition(cast<RecordDecl>(FromDC), ToRecord,
5745                                   ASTNodeImporter::IDK_Everything);
5746         return;
5747       }
5748     }
5749
5750     if (EnumDecl *ToEnum = dyn_cast<EnumDecl>(To)) {
5751       if (!ToEnum->getDefinition()) {
5752         Importer.ImportDefinition(cast<EnumDecl>(FromDC), ToEnum,
5753                                   ASTNodeImporter::IDK_Everything);
5754         return;
5755       }
5756     }
5757
5758     if (ObjCInterfaceDecl *ToIFace = dyn_cast<ObjCInterfaceDecl>(To)) {
5759       if (!ToIFace->getDefinition()) {
5760         Importer.ImportDefinition(cast<ObjCInterfaceDecl>(FromDC), ToIFace,
5761                                   ASTNodeImporter::IDK_Everything);
5762         return;
5763       }
5764     }
5765
5766     if (ObjCProtocolDecl *ToProto = dyn_cast<ObjCProtocolDecl>(To)) {
5767       if (!ToProto->getDefinition()) {
5768         Importer.ImportDefinition(cast<ObjCProtocolDecl>(FromDC), ToProto,
5769                                   ASTNodeImporter::IDK_Everything);
5770         return;
5771       }
5772     }
5773
5774     Importer.ImportDeclContext(FromDC, true);
5775   }
5776 }
5777
5778 DeclarationName ASTImporter::Import(DeclarationName FromName) {
5779   if (!FromName)
5780     return DeclarationName();
5781
5782   switch (FromName.getNameKind()) {
5783   case DeclarationName::Identifier:
5784     return Import(FromName.getAsIdentifierInfo());
5785
5786   case DeclarationName::ObjCZeroArgSelector:
5787   case DeclarationName::ObjCOneArgSelector:
5788   case DeclarationName::ObjCMultiArgSelector:
5789     return Import(FromName.getObjCSelector());
5790
5791   case DeclarationName::CXXConstructorName: {
5792     QualType T = Import(FromName.getCXXNameType());
5793     if (T.isNull())
5794       return DeclarationName();
5795
5796     return ToContext.DeclarationNames.getCXXConstructorName(
5797                                                ToContext.getCanonicalType(T));
5798   }
5799
5800   case DeclarationName::CXXDestructorName: {
5801     QualType T = Import(FromName.getCXXNameType());
5802     if (T.isNull())
5803       return DeclarationName();
5804
5805     return ToContext.DeclarationNames.getCXXDestructorName(
5806                                                ToContext.getCanonicalType(T));
5807   }
5808
5809   case DeclarationName::CXXConversionFunctionName: {
5810     QualType T = Import(FromName.getCXXNameType());
5811     if (T.isNull())
5812       return DeclarationName();
5813
5814     return ToContext.DeclarationNames.getCXXConversionFunctionName(
5815                                                ToContext.getCanonicalType(T));
5816   }
5817
5818   case DeclarationName::CXXOperatorName:
5819     return ToContext.DeclarationNames.getCXXOperatorName(
5820                                           FromName.getCXXOverloadedOperator());
5821
5822   case DeclarationName::CXXLiteralOperatorName:
5823     return ToContext.DeclarationNames.getCXXLiteralOperatorName(
5824                                    Import(FromName.getCXXLiteralIdentifier()));
5825
5826   case DeclarationName::CXXUsingDirective:
5827     // FIXME: STATICS!
5828     return DeclarationName::getUsingDirectiveName();
5829   }
5830
5831   llvm_unreachable("Invalid DeclarationName Kind!");
5832 }
5833
5834 IdentifierInfo *ASTImporter::Import(const IdentifierInfo *FromId) {
5835   if (!FromId)
5836     return nullptr;
5837
5838   return &ToContext.Idents.get(FromId->getName());
5839 }
5840
5841 Selector ASTImporter::Import(Selector FromSel) {
5842   if (FromSel.isNull())
5843     return Selector();
5844
5845   SmallVector<IdentifierInfo *, 4> Idents;
5846   Idents.push_back(Import(FromSel.getIdentifierInfoForSlot(0)));
5847   for (unsigned I = 1, N = FromSel.getNumArgs(); I < N; ++I)
5848     Idents.push_back(Import(FromSel.getIdentifierInfoForSlot(I)));
5849   return ToContext.Selectors.getSelector(FromSel.getNumArgs(), Idents.data());
5850 }
5851
5852 DeclarationName ASTImporter::HandleNameConflict(DeclarationName Name,
5853                                                 DeclContext *DC,
5854                                                 unsigned IDNS,
5855                                                 NamedDecl **Decls,
5856                                                 unsigned NumDecls) {
5857   return Name;
5858 }
5859
5860 DiagnosticBuilder ASTImporter::ToDiag(SourceLocation Loc, unsigned DiagID) {
5861   if (LastDiagFromFrom)
5862     ToContext.getDiagnostics().notePriorDiagnosticFrom(
5863       FromContext.getDiagnostics());
5864   LastDiagFromFrom = false;
5865   return ToContext.getDiagnostics().Report(Loc, DiagID);
5866 }
5867
5868 DiagnosticBuilder ASTImporter::FromDiag(SourceLocation Loc, unsigned DiagID) {
5869   if (!LastDiagFromFrom)
5870     FromContext.getDiagnostics().notePriorDiagnosticFrom(
5871       ToContext.getDiagnostics());
5872   LastDiagFromFrom = true;
5873   return FromContext.getDiagnostics().Report(Loc, DiagID);
5874 }
5875
5876 void ASTImporter::CompleteDecl (Decl *D) {
5877   if (ObjCInterfaceDecl *ID = dyn_cast<ObjCInterfaceDecl>(D)) {
5878     if (!ID->getDefinition())
5879       ID->startDefinition();
5880   }
5881   else if (ObjCProtocolDecl *PD = dyn_cast<ObjCProtocolDecl>(D)) {
5882     if (!PD->getDefinition())
5883       PD->startDefinition();
5884   }
5885   else if (TagDecl *TD = dyn_cast<TagDecl>(D)) {
5886     if (!TD->getDefinition() && !TD->isBeingDefined()) {
5887       TD->startDefinition();
5888       TD->setCompleteDefinition(true);
5889     }
5890   }
5891   else {
5892     assert (0 && "CompleteDecl called on a Decl that can't be completed");
5893   }
5894 }
5895
5896 Decl *ASTImporter::Imported(Decl *From, Decl *To) {
5897   ImportedDecls[From] = To;
5898   return To;
5899 }
5900
5901 bool ASTImporter::IsStructurallyEquivalent(QualType From, QualType To,
5902                                            bool Complain) {
5903   llvm::DenseMap<const Type *, const Type *>::iterator Pos
5904    = ImportedTypes.find(From.getTypePtr());
5905   if (Pos != ImportedTypes.end() && ToContext.hasSameType(Import(From), To))
5906     return true;
5907
5908   StructuralEquivalenceContext Ctx(FromContext, ToContext, NonEquivalentDecls,
5909                                    false, Complain);
5910   return Ctx.IsStructurallyEquivalent(From, To);
5911 }