/contrib/llvm/tools/clang/lib/Rewrite/RewriteModernObjC.cpp

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//===--- RewriteObjC.cpp - Playground for the code rewriter ---------------===//
//
//                     The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// Hacks and fun related to the code rewriter.
//
//===----------------------------------------------------------------------===//

#include "clang/Rewrite/ASTConsumers.h"
#include "clang/Rewrite/Rewriter.h"
#include "clang/AST/AST.h"
#include "clang/AST/ASTConsumer.h"
#include "clang/AST/ParentMap.h"
#include "clang/Basic/SourceManager.h"
#include "clang/Basic/IdentifierTable.h"
#include "clang/Basic/Diagnostic.h"
#include "clang/Lex/Lexer.h"
#include "llvm/Support/MemoryBuffer.h"
#include "llvm/Support/raw_ostream.h"
#include "llvm/ADT/StringExtras.h"
#include "llvm/ADT/SmallPtrSet.h"
#include "llvm/ADT/OwningPtr.h"
#include "llvm/ADT/DenseSet.h"

using namespace clang;
using llvm::utostr;

namespace {
  class RewriteModernObjC : public ASTConsumer {
  protected:
    
    enum {
      BLOCK_FIELD_IS_OBJECT   =  3,  /* id, NSObject, __attribute__((NSObject)),
                                        block, ... */
      BLOCK_FIELD_IS_BLOCK    =  7,  /* a block variable */
      BLOCK_FIELD_IS_BYREF    =  8,  /* the on stack structure holding the 
                                        __block variable */
      BLOCK_FIELD_IS_WEAK     = 16,  /* declared __weak, only used in byref copy
                                        helpers */
      BLOCK_BYREF_CALLER      = 128, /* called from __block (byref) copy/dispose
                                        support routines */
      BLOCK_BYREF_CURRENT_MAX = 256
    };
    
    enum {
      BLOCK_NEEDS_FREE =        (1 << 24),
      BLOCK_HAS_COPY_DISPOSE =  (1 << 25),
      BLOCK_HAS_CXX_OBJ =       (1 << 26),
      BLOCK_IS_GC =             (1 << 27),
      BLOCK_IS_GLOBAL =         (1 << 28),
      BLOCK_HAS_DESCRIPTOR =    (1 << 29)
    };
    static const int OBJC_ABI_VERSION = 7;
    
    Rewriter Rewrite;
    DiagnosticsEngine &Diags;
    const LangOptions &LangOpts;
    ASTContext *Context;
    SourceManager *SM;
    TranslationUnitDecl *TUDecl;
    FileID MainFileID;
    const char *MainFileStart, *MainFileEnd;
    Stmt *CurrentBody;
    ParentMap *PropParentMap; // created lazily.
    std::string InFileName;
    raw_ostream* OutFile;
    std::string Preamble;
    
    TypeDecl *ProtocolTypeDecl;
    VarDecl *GlobalVarDecl;
    Expr *GlobalConstructionExp;
    unsigned RewriteFailedDiag;
    unsigned GlobalBlockRewriteFailedDiag;
    // ObjC string constant support.
    unsigned NumObjCStringLiterals;
    VarDecl *ConstantStringClassReference;
    RecordDecl *NSStringRecord;

    // ObjC foreach break/continue generation support.
    int BcLabelCount;
    
    unsigned TryFinallyContainsReturnDiag;
    // Needed for super.
    ObjCMethodDecl *CurMethodDef;
    RecordDecl *SuperStructDecl;
    RecordDecl *ConstantStringDecl;
    
    FunctionDecl *MsgSendFunctionDecl;
    FunctionDecl *MsgSendSuperFunctionDecl;
    FunctionDecl *MsgSendStretFunctionDecl;
    FunctionDecl *MsgSendSuperStretFunctionDecl;
    FunctionDecl *MsgSendFpretFunctionDecl;
    FunctionDecl *GetClassFunctionDecl;
    FunctionDecl *GetMetaClassFunctionDecl;
    FunctionDecl *GetSuperClassFunctionDecl;
    FunctionDecl *SelGetUidFunctionDecl;
    FunctionDecl *CFStringFunctionDecl;
    FunctionDecl *SuperContructorFunctionDecl;
    FunctionDecl *CurFunctionDef;

    /* Misc. containers needed for meta-data rewrite. */
    SmallVector<ObjCImplementationDecl *, 8> ClassImplementation;
    SmallVector<ObjCCategoryImplDecl *, 8> CategoryImplementation;
    llvm::SmallPtrSet<ObjCInterfaceDecl*, 8> ObjCSynthesizedStructs;
    llvm::SmallPtrSet<ObjCProtocolDecl*, 8> ObjCSynthesizedProtocols;
    llvm::SmallPtrSet<ObjCInterfaceDecl*, 8> ObjCWrittenInterfaces;
    llvm::SmallPtrSet<TagDecl*, 32> GlobalDefinedTags;
    SmallVector<ObjCInterfaceDecl*, 32> ObjCInterfacesSeen;
    /// DefinedNonLazyClasses - List of defined "non-lazy" classes.
    SmallVector<ObjCInterfaceDecl*, 8> DefinedNonLazyClasses;
    
    /// DefinedNonLazyCategories - List of defined "non-lazy" categories.
    llvm::SmallVector<ObjCCategoryDecl*, 8> DefinedNonLazyCategories;
    
    SmallVector<Stmt *, 32> Stmts;
    SmallVector<int, 8> ObjCBcLabelNo;
    // Remember all the @protocol(<expr>) expressions.
    llvm::SmallPtrSet<ObjCProtocolDecl *, 32> ProtocolExprDecls;
    
    llvm::DenseSet<uint64_t> CopyDestroyCache;

    // Block expressions.
    SmallVector<BlockExpr *, 32> Blocks;
    SmallVector<int, 32> InnerDeclRefsCount;
    SmallVector<DeclRefExpr *, 32> InnerDeclRefs;
    
    SmallVector<DeclRefExpr *, 32> BlockDeclRefs;

    // Block related declarations.
    SmallVector<ValueDecl *, 8> BlockByCopyDecls;
    llvm::SmallPtrSet<ValueDecl *, 8> BlockByCopyDeclsPtrSet;
    SmallVector<ValueDecl *, 8> BlockByRefDecls;
    llvm::SmallPtrSet<ValueDecl *, 8> BlockByRefDeclsPtrSet;
    llvm::DenseMap<ValueDecl *, unsigned> BlockByRefDeclNo;
    llvm::SmallPtrSet<ValueDecl *, 8> ImportedBlockDecls;
    llvm::SmallPtrSet<VarDecl *, 8> ImportedLocalExternalDecls;
    
    llvm::DenseMap<BlockExpr *, std::string> RewrittenBlockExprs;
    llvm::DenseMap<ObjCInterfaceDecl *, 
                    llvm::SmallPtrSet<ObjCIvarDecl *, 8> > ReferencedIvars;
    
    // This maps an original source AST to it's rewritten form. This allows
    // us to avoid rewriting the same node twice (which is very uncommon).
    // This is needed to support some of the exotic property rewriting.
    llvm::DenseMap<Stmt *, Stmt *> ReplacedNodes;

    // Needed for header files being rewritten
    bool IsHeader;
    bool SilenceRewriteMacroWarning;
    bool objc_impl_method;
    
    bool DisableReplaceStmt;
    class DisableReplaceStmtScope {
      RewriteModernObjC &R;
      bool SavedValue;
    
    public:
      DisableReplaceStmtScope(RewriteModernObjC &R)
        : R(R), SavedValue(R.DisableReplaceStmt) {
        R.DisableReplaceStmt = true;
      }
      ~DisableReplaceStmtScope() {
        R.DisableReplaceStmt = SavedValue;
      }
    };
    void InitializeCommon(ASTContext &context);

  public:
    llvm::DenseMap<ObjCMethodDecl*, std::string> MethodInternalNames;
    // Top Level Driver code.
    virtual bool HandleTopLevelDecl(DeclGroupRef D) {
      for (DeclGroupRef::iterator I = D.begin(), E = D.end(); I != E; ++I) {
        if (ObjCInterfaceDecl *Class = dyn_cast<ObjCInterfaceDecl>(*I)) {
          if (!Class->isThisDeclarationADefinition()) {
            RewriteForwardClassDecl(D);
            break;
          } else {
            // Keep track of all interface declarations seen.
            ObjCInterfacesSeen.push_back(Class);
            break;
          }
        }

        if (ObjCProtocolDecl *Proto = dyn_cast<ObjCProtocolDecl>(*I)) {
          if (!Proto->isThisDeclarationADefinition()) {
            RewriteForwardProtocolDecl(D);
            break;
          }
        }

        HandleTopLevelSingleDecl(*I);
      }
      return true;
    }
    void HandleTopLevelSingleDecl(Decl *D);
    void HandleDeclInMainFile(Decl *D);
    RewriteModernObjC(std::string inFile, raw_ostream *OS,
                DiagnosticsEngine &D, const LangOptions &LOpts,
                bool silenceMacroWarn);
    
    ~RewriteModernObjC() {}
    
    virtual void HandleTranslationUnit(ASTContext &C);

    void ReplaceStmt(Stmt *Old, Stmt *New) {
      Stmt *ReplacingStmt = ReplacedNodes[Old];

      if (ReplacingStmt)
        return; // We can't rewrite the same node twice.

      if (DisableReplaceStmt)
        return;

      // If replacement succeeded or warning disabled return with no warning.
      if (!Rewrite.ReplaceStmt(Old, New)) {
        ReplacedNodes[Old] = New;
        return;
      }
      if (SilenceRewriteMacroWarning)
        return;
      Diags.Report(Context->getFullLoc(Old->getLocStart()), RewriteFailedDiag)
                   << Old->getSourceRange();
    }

    void ReplaceStmtWithRange(Stmt *Old, Stmt *New, SourceRange SrcRange) {
      if (DisableReplaceStmt)
        return;

      // Measure the old text.
      int Size = Rewrite.getRangeSize(SrcRange);
      if (Size == -1) {
        Diags.Report(Context->getFullLoc(Old->getLocStart()), RewriteFailedDiag)
                     << Old->getSourceRange();
        return;
      }
      // Get the new text.
      std::string SStr;
      llvm::raw_string_ostream S(SStr);
      New->printPretty(S, 0, PrintingPolicy(LangOpts));
      const std::string &Str = S.str();

      // If replacement succeeded or warning disabled return with no warning.
      if (!Rewrite.ReplaceText(SrcRange.getBegin(), Size, Str)) {
        ReplacedNodes[Old] = New;
        return;
      }
      if (SilenceRewriteMacroWarning)
        return;
      Diags.Report(Context->getFullLoc(Old->getLocStart()), RewriteFailedDiag)
                   << Old->getSourceRange();
    }

    void InsertText(SourceLocation Loc, StringRef Str,
                    bool InsertAfter = true) {
      // If insertion succeeded or warning disabled return with no warning.
      if (!Rewrite.InsertText(Loc, Str, InsertAfter) ||
          SilenceRewriteMacroWarning)
        return;

      Diags.Report(Context->getFullLoc(Loc), RewriteFailedDiag);
    }

    void ReplaceText(SourceLocation Start, unsigned OrigLength,
                     StringRef Str) {
      // If removal succeeded or warning disabled return with no warning.
      if (!Rewrite.ReplaceText(Start, OrigLength, Str) ||
          SilenceRewriteMacroWarning)
        return;

      Diags.Report(Context->getFullLoc(Start), RewriteFailedDiag);
    }

    // Syntactic Rewriting.
    void RewriteRecordBody(RecordDecl *RD);
    void RewriteInclude();
    void RewriteForwardClassDecl(DeclGroupRef D);
    void RewriteForwardClassDecl(const llvm::SmallVector<Decl*, 8> &DG);
    void RewriteForwardClassEpilogue(ObjCInterfaceDecl *ClassDecl, 
                                     const std::string &typedefString);
    void RewriteImplementations();
    void RewritePropertyImplDecl(ObjCPropertyImplDecl *PID,
                                 ObjCImplementationDecl *IMD,
                                 ObjCCategoryImplDecl *CID);
    void RewriteInterfaceDecl(ObjCInterfaceDecl *Dcl);
    void RewriteImplementationDecl(Decl *Dcl);
    void RewriteObjCMethodDecl(const ObjCInterfaceDecl *IDecl,
                               ObjCMethodDecl *MDecl, std::string &ResultStr);
    void RewriteTypeIntoString(QualType T, std::string &ResultStr,
                               const FunctionType *&FPRetType);
    void RewriteByRefString(std::string &ResultStr, const std::string &Name,
                            ValueDecl *VD, bool def=false);
    void RewriteCategoryDecl(ObjCCategoryDecl *Dcl);
    void RewriteProtocolDecl(ObjCProtocolDecl *Dcl);
    void RewriteForwardProtocolDecl(DeclGroupRef D);
    void RewriteForwardProtocolDecl(const llvm::SmallVector<Decl*, 8> &DG);
    void RewriteMethodDeclaration(ObjCMethodDecl *Method);
    void RewriteProperty(ObjCPropertyDecl *prop);
    void RewriteFunctionDecl(FunctionDecl *FD);
    void RewriteBlockPointerType(std::string& Str, QualType Type);
    void RewriteBlockPointerTypeVariable(std::string& Str, ValueDecl *VD);
    void RewriteBlockLiteralFunctionDecl(FunctionDecl *FD);
    void RewriteObjCQualifiedInterfaceTypes(Decl *Dcl);
    void RewriteTypeOfDecl(VarDecl *VD);
    void RewriteObjCQualifiedInterfaceTypes(Expr *E);
    
    std::string getIvarAccessString(ObjCIvarDecl *D);
  
    // Expression Rewriting.
    Stmt *RewriteFunctionBodyOrGlobalInitializer(Stmt *S);
    Stmt *RewriteAtEncode(ObjCEncodeExpr *Exp);
    Stmt *RewritePropertyOrImplicitGetter(PseudoObjectExpr *Pseudo);
    Stmt *RewritePropertyOrImplicitSetter(PseudoObjectExpr *Pseudo);
    Stmt *RewriteAtSelector(ObjCSelectorExpr *Exp);
    Stmt *RewriteMessageExpr(ObjCMessageExpr *Exp);
    Stmt *RewriteObjCStringLiteral(ObjCStringLiteral *Exp);
    Stmt *RewriteObjCBoolLiteralExpr(ObjCBoolLiteralExpr *Exp);
    Stmt *RewriteObjCBoxedExpr(ObjCBoxedExpr *Exp);
    Stmt *RewriteObjCArrayLiteralExpr(ObjCArrayLiteral *Exp);
    Stmt *RewriteObjCDictionaryLiteralExpr(ObjCDictionaryLiteral *Exp);
    Stmt *RewriteObjCProtocolExpr(ObjCProtocolExpr *Exp);
    Stmt *RewriteObjCTryStmt(ObjCAtTryStmt *S);
    Stmt *RewriteObjCAutoreleasePoolStmt(ObjCAutoreleasePoolStmt  *S);
    Stmt *RewriteObjCSynchronizedStmt(ObjCAtSynchronizedStmt *S);
    Stmt *RewriteObjCThrowStmt(ObjCAtThrowStmt *S);
    Stmt *RewriteObjCForCollectionStmt(ObjCForCollectionStmt *S,
                                       SourceLocation OrigEnd);
    Stmt *RewriteBreakStmt(BreakStmt *S);
    Stmt *RewriteContinueStmt(ContinueStmt *S);
    void RewriteCastExpr(CStyleCastExpr *CE);
    void RewriteImplicitCastObjCExpr(CastExpr *IE);
    void RewriteLinkageSpec(LinkageSpecDecl *LSD);
    
    // Block rewriting.
    void RewriteBlocksInFunctionProtoType(QualType funcType, NamedDecl *D);
    
    // Block specific rewrite rules.
    void RewriteBlockPointerDecl(NamedDecl *VD);
    void RewriteByRefVar(VarDecl *VD, bool firstDecl, bool lastDecl);
    Stmt *RewriteBlockDeclRefExpr(DeclRefExpr *VD);
    Stmt *RewriteLocalVariableExternalStorage(DeclRefExpr *DRE);
    void RewriteBlockPointerFunctionArgs(FunctionDecl *FD);
    
    void RewriteObjCInternalStruct(ObjCInterfaceDecl *CDecl,
                                      std::string &Result);
    
    void RewriteObjCFieldDecl(FieldDecl *fieldDecl, std::string &Result);
    bool IsTagDefinedInsideClass(ObjCContainerDecl *IDecl, TagDecl *Tag,
                                 bool &IsNamedDefinition);
    void RewriteLocallyDefinedNamedAggregates(FieldDecl *fieldDecl, 
                                              std::string &Result);
    
    bool RewriteObjCFieldDeclType(QualType &Type, std::string &Result);
    
    void RewriteIvarOffsetSymbols(ObjCInterfaceDecl *CDecl,
                                  std::string &Result);
    
    virtual void Initialize(ASTContext &context);
    
    // Misc. AST transformation routines. Sometimes they end up calling
    // rewriting routines on the new ASTs.
    CallExpr *SynthesizeCallToFunctionDecl(FunctionDecl *FD,
                                           Expr **args, unsigned nargs,
                                           SourceLocation StartLoc=SourceLocation(),
                                           SourceLocation EndLoc=SourceLocation());
    
    Expr *SynthMsgSendStretCallExpr(FunctionDecl *MsgSendStretFlavor,
                                        QualType msgSendType, 
                                        QualType returnType, 
                                        SmallVectorImpl<QualType> &ArgTypes,
                                        SmallVectorImpl<Expr*> &MsgExprs,
                                        ObjCMethodDecl *Method);

    Stmt *SynthMessageExpr(ObjCMessageExpr *Exp,
                           SourceLocation StartLoc=SourceLocation(),
                           SourceLocation EndLoc=SourceLocation());
    
    void SynthCountByEnumWithState(std::string &buf);
    void SynthMsgSendFunctionDecl();
    void SynthMsgSendSuperFunctionDecl();
    void SynthMsgSendStretFunctionDecl();
    void SynthMsgSendFpretFunctionDecl();
    void SynthMsgSendSuperStretFunctionDecl();
    void SynthGetClassFunctionDecl();
    void SynthGetMetaClassFunctionDecl();
    void SynthGetSuperClassFunctionDecl();
    void SynthSelGetUidFunctionDecl();
    void SynthSuperContructorFunctionDecl();
    
    // Rewriting metadata
    template<typename MethodIterator>
    void RewriteObjCMethodsMetaData(MethodIterator MethodBegin,
                                    MethodIterator MethodEnd,
                                    bool IsInstanceMethod,
                                    StringRef prefix,
                                    StringRef ClassName,
                                    std::string &Result);
    void RewriteObjCProtocolMetaData(ObjCProtocolDecl *Protocol,
                                     std::string &Result);
    void RewriteObjCProtocolListMetaData(
                   const ObjCList<ObjCProtocolDecl> &Prots,
                   StringRef prefix, StringRef ClassName, std::string &Result);
    void RewriteObjCClassMetaData(ObjCImplementationDecl *IDecl,
                                          std::string &Result);
    void RewriteClassSetupInitHook(std::string &Result);
    
    void RewriteMetaDataIntoBuffer(std::string &Result);
    void WriteImageInfo(std::string &Result);
    void RewriteObjCCategoryImplDecl(ObjCCategoryImplDecl *CDecl,
                                             std::string &Result);
    void RewriteCategorySetupInitHook(std::string &Result);
    
    // Rewriting ivar
    void RewriteIvarOffsetComputation(ObjCIvarDecl *ivar,
                                              std::string &Result);
    Stmt *RewriteObjCIvarRefExpr(ObjCIvarRefExpr *IV);

    
    std::string SynthesizeByrefCopyDestroyHelper(VarDecl *VD, int flag);
    std::string SynthesizeBlockHelperFuncs(BlockExpr *CE, int i,
                                      StringRef funcName, std::string Tag);
    std::string SynthesizeBlockFunc(BlockExpr *CE, int i,
                                      StringRef funcName, std::string Tag);
    std::string SynthesizeBlockImpl(BlockExpr *CE, 
                                    std::string Tag, std::string Desc);
    std::string SynthesizeBlockDescriptor(std::string DescTag, 
                                          std::string ImplTag,
                                          int i, StringRef funcName,
                                          unsigned hasCopy);
    Stmt *SynthesizeBlockCall(CallExpr *Exp, const Expr* BlockExp);
    void SynthesizeBlockLiterals(SourceLocation FunLocStart,
                                 StringRef FunName);
    FunctionDecl *SynthBlockInitFunctionDecl(StringRef name);
    Stmt *SynthBlockInitExpr(BlockExpr *Exp,
            const SmallVector<DeclRefExpr *, 8> &InnerBlockDeclRefs);

    // Misc. helper routines.
    QualType getProtocolType();
    void WarnAboutReturnGotoStmts(Stmt *S);
    void CheckFunctionPointerDecl(QualType dType, NamedDecl *ND);
    void InsertBlockLiteralsWithinFunction(FunctionDecl *FD);
    void InsertBlockLiteralsWithinMethod(ObjCMethodDecl *MD);

    bool IsDeclStmtInForeachHeader(DeclStmt *DS);
    void CollectBlockDeclRefInfo(BlockExpr *Exp);
    void GetBlockDeclRefExprs(Stmt *S);
    void GetInnerBlockDeclRefExprs(Stmt *S, 
                SmallVector<DeclRefExpr *, 8> &InnerBlockDeclRefs,
                llvm::SmallPtrSet<const DeclContext *, 8> &InnerContexts);

    // We avoid calling Type::isBlockPointerType(), since it operates on the
    // canonical type. We only care if the top-level type is a closure pointer.
    bool isTopLevelBlockPointerType(QualType T) {
      return isa<BlockPointerType>(T);
    }

    /// convertBlockPointerToFunctionPointer - Converts a block-pointer type
    /// to a function pointer type and upon success, returns true; false
    /// otherwise.
    bool convertBlockPointerToFunctionPointer(QualType &T) {
      if (isTopLevelBlockPointerType(T)) {
        const BlockPointerType *BPT = T->getAs<BlockPointerType>();
        T = Context->getPointerType(BPT->getPointeeType());
        return true;
      }
      return false;
    }
    
    bool convertObjCTypeToCStyleType(QualType &T);
    
    bool needToScanForQualifiers(QualType T);
    QualType getSuperStructType();
    QualType getConstantStringStructType();
    QualType convertFunctionTypeOfBlocks(const FunctionType *FT);
    bool BufferContainsPPDirectives(const char *startBuf, const char *endBuf);
    
    void convertToUnqualifiedObjCType(QualType &T) {
      if (T->isObjCQualifiedIdType()) {
        bool isConst = T.isConstQualified();
        T = isConst ? Context->getObjCIdType().withConst() 
                    : Context->getObjCIdType();
      }
      else if (T->isObjCQualifiedClassType())
        T = Context->getObjCClassType();
      else if (T->isObjCObjectPointerType() &&
               T->getPointeeType()->isObjCQualifiedInterfaceType()) {
        if (const ObjCObjectPointerType * OBJPT =
              T->getAsObjCInterfacePointerType()) {
          const ObjCInterfaceType *IFaceT = OBJPT->getInterfaceType();
          T = QualType(IFaceT, 0);
          T = Context->getPointerType(T);
        }
     }
    }
    
    // FIXME: This predicate seems like it would be useful to add to ASTContext.
    bool isObjCType(QualType T) {
      if (!LangOpts.ObjC1 && !LangOpts.ObjC2)
        return false;

      QualType OCT = Context->getCanonicalType(T).getUnqualifiedType();

      if (OCT == Context->getCanonicalType(Context->getObjCIdType()) ||
          OCT == Context->getCanonicalType(Context->getObjCClassType()))
        return true;

      if (const PointerType *PT = OCT->getAs<PointerType>()) {
        if (isa<ObjCInterfaceType>(PT->getPointeeType()) ||
            PT->getPointeeType()->isObjCQualifiedIdType())
          return true;
      }
      return false;
    }
    bool PointerTypeTakesAnyBlockArguments(QualType QT);
    bool PointerTypeTakesAnyObjCQualifiedType(QualType QT);
    void GetExtentOfArgList(const char *Name, const char *&LParen,
                            const char *&RParen);
    
    void QuoteDoublequotes(std::string &From, std::string &To) {
      for (unsigned i = 0; i < From.length(); i++) {
        if (From[i] == '"')
          To += "\\\"";
        else
          To += From[i];
      }
    }

    QualType getSimpleFunctionType(QualType result,
                                   const QualType *args,
                                   unsigned numArgs,
                                   bool variadic = false) {
      if (result == Context->getObjCInstanceType())
        result =  Context->getObjCIdType();
      FunctionProtoType::ExtProtoInfo fpi;
      fpi.Variadic = variadic;
      return Context->getFunctionType(result, args, numArgs, fpi);
    }

    // Helper function: create a CStyleCastExpr with trivial type source info.
    CStyleCastExpr* NoTypeInfoCStyleCastExpr(ASTContext *Ctx, QualType Ty,
                                             CastKind Kind, Expr *E) {
      TypeSourceInfo *TInfo = Ctx->getTrivialTypeSourceInfo(Ty, SourceLocation());
      return CStyleCastExpr::Create(*Ctx, Ty, VK_RValue, Kind, E, 0, TInfo,
                                    SourceLocation(), SourceLocation());
    }
    
    bool ImplementationIsNonLazy(const ObjCImplDecl *OD) const {
      IdentifierInfo* II = &Context->Idents.get("load");
      Selector LoadSel = Context->Selectors.getSelector(0, &II);
      return OD->getClassMethod(LoadSel) != 0;
    }
  };
  
}

void RewriteModernObjC::RewriteBlocksInFunctionProtoType(QualType funcType,
                                                   NamedDecl *D) {
  if (const FunctionProtoType *fproto
      = dyn_cast<FunctionProtoType>(funcType.IgnoreParens())) {
    for (FunctionProtoType::arg_type_iterator I = fproto->arg_type_begin(),
         E = fproto->arg_type_end(); I && (I != E); ++I)
      if (isTopLevelBlockPointerType(*I)) {
        // All the args are checked/rewritten. Don't call twice!
        RewriteBlockPointerDecl(D);
        break;
      }
  }
}

void RewriteModernObjC::CheckFunctionPointerDecl(QualType funcType, NamedDecl *ND) {
  const PointerType *PT = funcType->getAs<PointerType>();
  if (PT && PointerTypeTakesAnyBlockArguments(funcType))
    RewriteBlocksInFunctionProtoType(PT->getPointeeType(), ND);
}

static bool IsHeaderFile(const std::string &Filename) {
  std::string::size_type DotPos = Filename.rfind('.');

  if (DotPos == std::string::npos) {
    // no file extension
    return false;
  }

  std::string Ext = std::string(Filename.begin()+DotPos+1, Filename.end());
  // C header: .h
  // C++ header: .hh or .H;
  return Ext == "h" || Ext == "hh" || Ext == "H";
}

RewriteModernObjC::RewriteModernObjC(std::string inFile, raw_ostream* OS,
                         DiagnosticsEngine &D, const LangOptions &LOpts,
                         bool silenceMacroWarn)
      : Diags(D), LangOpts(LOpts), InFileName(inFile), OutFile(OS),
        SilenceRewriteMacroWarning(silenceMacroWarn) {
  IsHeader = IsHeaderFile(inFile);
  RewriteFailedDiag = Diags.getCustomDiagID(DiagnosticsEngine::Warning,
               "rewriting sub-expression within a macro (may not be correct)");
  // FIXME. This should be an error. But if block is not called, it is OK. And it
  // may break including some headers.
  GlobalBlockRewriteFailedDiag = Diags.getCustomDiagID(DiagnosticsEngine::Warning,
    "rewriting block literal declared in global scope is not implemented");
          
  TryFinallyContainsReturnDiag = Diags.getCustomDiagID(
               DiagnosticsEngine::Warning,
               "rewriter doesn't support user-specified control flow semantics "
               "for @try/@finally (code may not execute properly)");
}

ASTConsumer *clang::CreateModernObjCRewriter(const std::string& InFile,
                                       raw_ostream* OS,
                                       DiagnosticsEngine &Diags,
                                       const LangOptions &LOpts,
                                       bool SilenceRewriteMacroWarning) {
    return new RewriteModernObjC(InFile, OS, Diags, LOpts, SilenceRewriteMacroWarning);
}

void RewriteModernObjC::InitializeCommon(ASTContext &context) {
  Context = &context;
  SM = &Context->getSourceManager();
  TUDecl = Context->getTranslationUnitDecl();
  MsgSendFunctionDecl = 0;
  MsgSendSuperFunctionDecl = 0;
  MsgSendStretFunctionDecl = 0;
  MsgSendSuperStretFunctionDecl = 0;
  MsgSendFpretFunctionDecl = 0;
  GetClassFunctionDecl = 0;
  GetMetaClassFunctionDecl = 0;
  GetSuperClassFunctionDecl = 0;
  SelGetUidFunctionDecl = 0;
  CFStringFunctionDecl = 0;
  ConstantStringClassReference = 0;
  NSStringRecord = 0;
  CurMethodDef = 0;
  CurFunctionDef = 0;
  GlobalVarDecl = 0;
  GlobalConstructionExp = 0;
  SuperStructDecl = 0;
  ProtocolTypeDecl = 0;
  ConstantStringDecl = 0;
  BcLabelCount = 0;
  SuperContructorFunctionDecl = 0;
  NumObjCStringLiterals = 0;
  PropParentMap = 0;
  CurrentBody = 0;
  DisableReplaceStmt = false;
  objc_impl_method = false;

  // Get the ID and start/end of the main file.
  MainFileID = SM->getMainFileID();
  const llvm::MemoryBuffer *MainBuf = SM->getBuffer(MainFileID);
  MainFileStart = MainBuf->getBufferStart();
  MainFileEnd = MainBuf->getBufferEnd();

  Rewrite.setSourceMgr(Context->getSourceManager(), Context->getLangOpts());
}

//===----------------------------------------------------------------------===//
// Top Level Driver Code
//===----------------------------------------------------------------------===//

void RewriteModernObjC::HandleTopLevelSingleDecl(Decl *D) {
  if (Diags.hasErrorOccurred())
    return;

  // Two cases: either the decl could be in the main file, or it could be in a
  // #included file.  If the former, rewrite it now.  If the later, check to see
  // if we rewrote the #include/#import.
  SourceLocation Loc = D->getLocation();
  Loc = SM->getExpansionLoc(Loc);

  // If this is for a builtin, ignore it.
  if (Loc.isInvalid()) return;

  // Look for built-in declarations that we need to refer during the rewrite.
  if (FunctionDecl *FD = dyn_cast<FunctionDecl>(D)) {
    RewriteFunctionDecl(FD);
  } else if (VarDecl *FVD = dyn_cast<VarDecl>(D)) {
    // declared in <Foundation/NSString.h>
    if (FVD->getName() == "_NSConstantStringClassReference") {
      ConstantStringClassReference = FVD;
      return;
    }
  } else if (ObjCCategoryDecl *CD = dyn_cast<ObjCCategoryDecl>(D)) {
    RewriteCategoryDecl(CD);
  } else if (ObjCProtocolDecl *PD = dyn_cast<ObjCProtocolDecl>(D)) {
    if (PD->isThisDeclarationADefinition())
      RewriteProtocolDecl(PD);
  } else if (LinkageSpecDecl *LSD = dyn_cast<LinkageSpecDecl>(D)) {
    // FIXME. This will not work in all situations and leaving it out
    // is harmless.
    // RewriteLinkageSpec(LSD);
    
    // Recurse into linkage specifications
    for (DeclContext::decl_iterator DI = LSD->decls_begin(),
                                 DIEnd = LSD->decls_end();
         DI != DIEnd; ) {
      if (ObjCInterfaceDecl *IFace = dyn_cast<ObjCInterfaceDecl>((*DI))) {
        if (!IFace->isThisDeclarationADefinition()) {
          SmallVector<Decl *, 8> DG;
          SourceLocation StartLoc = IFace->getLocStart();
          do {
            if (isa<ObjCInterfaceDecl>(*DI) &&
                !cast<ObjCInterfaceDecl>(*DI)->isThisDeclarationADefinition() &&
                StartLoc == (*DI)->getLocStart())
              DG.push_back(*DI);
            else
              break;
            
            ++DI;
          } while (DI != DIEnd);
          RewriteForwardClassDecl(DG);
          continue;
        }
        else {
          // Keep track of all interface declarations seen.
          ObjCInterfacesSeen.push_back(IFace);
          ++DI;
          continue;
        }
      }

      if (ObjCProtocolDecl *Proto = dyn_cast<ObjCProtocolDecl>((*DI))) {
        if (!Proto->isThisDeclarationADefinition()) {
          SmallVector<Decl *, 8> DG;
          SourceLocation StartLoc = Proto->getLocStart();
          do {
            if (isa<ObjCProtocolDecl>(*DI) &&
                !cast<ObjCProtocolDecl>(*DI)->isThisDeclarationADefinition() &&
                StartLoc == (*DI)->getLocStart())
              DG.push_back(*DI);
            else
              break;
            
            ++DI;
          } while (DI != DIEnd);
          RewriteForwardProtocolDecl(DG);
          continue;
        }
      }
      
      HandleTopLevelSingleDecl(*DI);
      ++DI;
    }
  }
  // If we have a decl in the main file, see if we should rewrite it.
  if (SM->isFromMainFile(Loc))
    return HandleDeclInMainFile(D);
}

//===----------------------------------------------------------------------===//
// Syntactic (non-AST) Rewriting Code
//===----------------------------------------------------------------------===//

void RewriteModernObjC::RewriteInclude() {
  SourceLocation LocStart = SM->getLocForStartOfFile(MainFileID);
  StringRef MainBuf = SM->getBufferData(MainFileID);
  const char *MainBufStart = MainBuf.begin();
  const char *MainBufEnd = MainBuf.end();
  size_t ImportLen = strlen("import");

  // Loop over the whole file, looking for includes.
  for (const char *BufPtr = MainBufStart; BufPtr < MainBufEnd; ++BufPtr) {
    if (*BufPtr == '#') {
      if (++BufPtr == MainBufEnd)
        return;
      while (*BufPtr == ' ' || *BufPtr == '\t')
        if (++BufPtr == MainBufEnd)
          return;
      if (!strncmp(BufPtr, "import", ImportLen)) {
        // replace import with include
        SourceLocation ImportLoc =
          LocStart.getLocWithOffset(BufPtr-MainBufStart);
        ReplaceText(ImportLoc, ImportLen, "include");
        BufPtr += ImportLen;
      }
    }
  }
}

static void WriteInternalIvarName(const ObjCInterfaceDecl *IDecl,
                                  ObjCIvarDecl *IvarDecl, std::string &Result) {
  Result += "OBJC_IVAR_$_";
  Result += IDecl->getName();
  Result += "$";
  Result += IvarDecl->getName();
}

std::string 
RewriteModernObjC::getIvarAccessString(ObjCIvarDecl *D) {
  const ObjCInterfaceDecl *ClassDecl = D->getContainingInterface();
  
  // Build name of symbol holding ivar offset.
  std::string IvarOffsetName;
  WriteInternalIvarName(ClassDecl, D, IvarOffsetName);
  
  
  std::string S = "(*(";
  QualType IvarT = D->getType();
  
  if (!isa<TypedefType>(IvarT) && IvarT->isRecordType()) {
    RecordDecl *RD = IvarT->getAs<RecordType>()->getDecl();
    RD = RD->getDefinition();
    if (RD && !RD->getDeclName().getAsIdentifierInfo()) {
      // decltype(((Foo_IMPL*)0)->bar) *
      ObjCContainerDecl *CDecl = 
      dyn_cast<ObjCContainerDecl>(D->getDeclContext());
      // ivar in class extensions requires special treatment.
      if (ObjCCategoryDecl *CatDecl = dyn_cast<ObjCCategoryDecl>(CDecl))
        CDecl = CatDecl->getClassInterface();
      std::string RecName = CDecl->getName();
      RecName += "_IMPL";
      RecordDecl *RD = RecordDecl::Create(*Context, TTK_Struct, TUDecl,
                                          SourceLocation(), SourceLocation(),
                                          &Context->Idents.get(RecName.c_str()));
      QualType PtrStructIMPL = Context->getPointerType(Context->getTagDeclType(RD));
      unsigned UnsignedIntSize = 
      static_cast<unsigned>(Context->getTypeSize(Context->UnsignedIntTy));
      Expr *Zero = IntegerLiteral::Create(*Context,
                                          llvm::APInt(UnsignedIntSize, 0),
                                          Context->UnsignedIntTy, SourceLocation());
      Zero = NoTypeInfoCStyleCastExpr(Context, PtrStructIMPL, CK_BitCast, Zero);
      ParenExpr *PE = new (Context) ParenExpr(SourceLocation(), SourceLocation(),
                                              Zero);
      FieldDecl *FD = FieldDecl::Create(*Context, 0, SourceLocation(),
                                        SourceLocation(),
                                        &Context->Idents.get(D->getNameAsString()),
                                        IvarT, 0,
                                        /*BitWidth=*/0, /*Mutable=*/true,
                                        ICIS_NoInit);
      MemberExpr *ME = new (Context) MemberExpr(PE, true, FD, SourceLocation(),
                                                FD->getType(), VK_LValue,
                                                OK_Ordinary);
      IvarT = Context->getDecltypeType(ME, ME->getType());
    }
  }
  convertObjCTypeToCStyleType(IvarT);
  QualType castT = Context->getPointerType(IvarT);
  std::string TypeString(castT.getAsString(Context->getPrintingPolicy()));
  S += TypeString;
  S += ")";
  
  // ((char *)self + IVAR_OFFSET_SYMBOL_NAME)
  S += "((char *)self + ";
  S += IvarOffsetName;
  S += "))";
  ReferencedIvars[const_cast<ObjCInterfaceDecl *>(ClassDecl)].insert(D);
  return S;
}

/// mustSynthesizeSetterGetterMethod - returns true if setter or getter has not
/// been found in the class implementation. In this case, it must be synthesized.
static bool mustSynthesizeSetterGetterMethod(ObjCImplementationDecl *IMP,
                                             ObjCPropertyDecl *PD,
                                             bool getter) {
  return getter ? !IMP->getInstanceMethod(PD->getGetterName())
                : !IMP->getInstanceMethod(PD->getSetterName());
  
}

void RewriteModernObjC::RewritePropertyImplDecl(ObjCPropertyImplDecl *PID,
                                          ObjCImplementationDecl *IMD,
                                          ObjCCategoryImplDecl *CID) {
  static bool objcGetPropertyDefined = false;
  static bool objcSetPropertyDefined = false;
  SourceLocation startGetterSetterLoc;
  
  if (PID->getLocStart().isValid()) {
    SourceLocation startLoc = PID->getLocStart();
    InsertText(startLoc, "// ");
    const char *startBuf = SM->getCharacterData(startLoc);
    assert((*startBuf == '@') && "bogus @synthesize location");
    const char *semiBuf = strchr(startBuf, ';');
    assert((*semiBuf == ';') && "@synthesize: can't find ';'");
    startGetterSetterLoc = startLoc.getLocWithOffset(semiBuf-startBuf+1);
  }
  else
    startGetterSetterLoc = IMD ? IMD->getLocEnd() : CID->getLocEnd();

  if (PID->getPropertyImplementation() == ObjCPropertyImplDecl::Dynamic)
    return; // FIXME: is this correct?

  // Generate the 'getter' function.
  ObjCPropertyDecl *PD = PID->getPropertyDecl();
  ObjCIvarDecl *OID = PID->getPropertyIvarDecl();

  if (!OID)
    return;
  unsigned Attributes = PD->getPropertyAttributes();
  if (mustSynthesizeSetterGetterMethod(IMD, PD, true /*getter*/)) {
    bool GenGetProperty = !(Attributes & ObjCPropertyDecl::OBJC_PR_nonatomic) &&
                          (Attributes & (ObjCPropertyDecl::OBJC_PR_retain | 
                                         ObjCPropertyDecl::OBJC_PR_copy));
    std::string Getr;
    if (GenGetProperty && !objcGetPropertyDefined) {
      objcGetPropertyDefined = true;
      // FIXME. Is this attribute correct in all cases?
      Getr = "\nextern \"C\" __declspec(dllimport) "
            "id objc_getProperty(id, SEL, long, bool);\n";
    }
    RewriteObjCMethodDecl(OID->getContainingInterface(),  
                          PD->getGetterMethodDecl(), Getr);
    Getr += "{ ";
    // Synthesize an explicit cast to gain access to the ivar.
    // See objc-act.c:objc_synthesize_new_getter() for details.
    if (GenGetProperty) {
      // return objc_getProperty(self, _cmd, offsetof(ClassDecl, OID), 1)
      Getr += "typedef ";
      const FunctionType *FPRetType = 0;
      RewriteTypeIntoString(PD->getGetterMethodDecl()->getResultType(), Getr, 
                            FPRetType);
      Getr += " _TYPE";
      if (FPRetType) {
        Getr += ")"; // close the precedence "scope" for "*".
      
        // Now, emit the argument types (if any).
        if (const FunctionProtoType *FT = dyn_cast<FunctionProtoType>(FPRetType)){
          Getr += "(";
          for (unsigned i = 0, e = FT->getNumArgs(); i != e; ++i) {
            if (i) Getr += ", ";
            std::string ParamStr = FT->getArgType(i).getAsString(
                                                          Context->getPrintingPolicy());
            Getr += ParamStr;
          }
          if (FT->isVariadic()) {
            if (FT->getNumArgs()) Getr += ", ";
            Getr += "...";
          }
          Getr += ")";
        } else
          Getr += "()";
      }
      Getr += ";\n";
      Getr += "return (_TYPE)";
      Getr += "objc_getProperty(self, _cmd, ";
      RewriteIvarOffsetComputation(OID, Getr);
      Getr += ", 1)";
    }
    else
      Getr += "return " + getIvarAccessString(OID);
    Getr += "; }";
    InsertText(startGetterSetterLoc, Getr);
  }
  
  if (PD->isReadOnly() || 
      !mustSynthesizeSetterGetterMethod(IMD, PD, false /*setter*/))
    return;

  // Generate the 'setter' function.
  std::string Setr;
  bool GenSetProperty = Attributes & (ObjCPropertyDecl::OBJC_PR_retain | 
                                      ObjCPropertyDecl::OBJC_PR_copy);
  if (GenSetProperty && !objcSetPropertyDefined) {
    objcSetPropertyDefined = true;
    // FIXME. Is this attribute correct in all cases?
    Setr = "\nextern \"C\" __declspec(dllimport) "
    "void objc_setProperty (id, SEL, long, id, bool, bool);\n";
  }
  
  RewriteObjCMethodDecl(OID->getContainingInterface(), 
                        PD->getSetterMethodDecl(), Setr);
  Setr += "{ ";
  // Synthesize an explicit cast to initialize the ivar.
  // See objc-act.c:objc_synthesize_new_setter() for details.
  if (GenSetProperty) {
    Setr += "objc_setProperty (self, _cmd, ";
    RewriteIvarOffsetComputation(OID, Setr);
    Setr += ", (id)";
    Setr += PD->getName();
    Setr += ", ";
    if (Attributes & ObjCPropertyDecl::OBJC_PR_nonatomic)
      Setr += "0, ";
    else
      Setr += "1, ";
    if (Attributes & ObjCPropertyDecl::OBJC_PR_copy)
      Setr += "1)";
    else
      Setr += "0)";
  }
  else {
    Setr += getIvarAccessString(OID) + " = ";
    Setr += PD->getName();
  }
  Setr += "; }\n";
  InsertText(startGetterSetterLoc, Setr);
}

static void RewriteOneForwardClassDecl(ObjCInterfaceDecl *ForwardDecl,
                                       std::string &typedefString) {
  typedefString += "#ifndef _REWRITER_typedef_";
  typedefString += ForwardDecl->getNameAsString();
  typedefString += "\n";
  typedefString += "#define _REWRITER_typedef_";
  typedefString += ForwardDecl->getNameAsString();
  typedefString += "\n";
  typedefString += "typedef struct objc_object ";
  typedefString += ForwardDecl->getNameAsString();
  // typedef struct { } _objc_exc_Classname;
  typedefString += ";\ntypedef struct {} _objc_exc_";
  typedefString += ForwardDecl->getNameAsString();
  typedefString += ";\n#endif\n";
}

void RewriteModernObjC::RewriteForwardClassEpilogue(ObjCInterfaceDecl *ClassDecl,
                                              const std::string &typedefString) {
    SourceLocation startLoc = ClassDecl->getLocStart();
    const char *startBuf = SM->getCharacterData(startLoc);
    const char *semiPtr = strchr(startBuf, ';'); 
    // Replace the @class with typedefs corresponding to the classes.
    ReplaceText(startLoc, semiPtr-startBuf+1, typedefString);  
}

void RewriteModernObjC::RewriteForwardClassDecl(DeclGroupRef D) {
  std::string typedefString;
  for (DeclGroupRef::iterator I = D.begin(), E = D.end(); I != E; ++I) {
    ObjCInterfaceDecl *ForwardDecl = cast<ObjCInterfaceDecl>(*I);
    if (I == D.begin()) {
      // Translate to typedef's that forward reference structs with the same name
      // as the class. As a convenience, we include the original declaration
      // as a comment.
      typedefString += "// @class ";
      typedefString += ForwardDecl->getNameAsString();
      typedefString += ";\n";
    }
    RewriteOneForwardClassDecl(ForwardDecl, typedefString);
  }
  DeclGroupRef::iterator I = D.begin();
  RewriteForwardClassEpilogue(cast<ObjCInterfaceDecl>(*I), typedefString);
}

void RewriteModernObjC::RewriteForwardClassDecl(
                                const llvm::SmallVector<Decl*, 8> &D) {
  std::string typedefString;
  for (unsigned i = 0; i < D.size(); i++) {
    ObjCInterfaceDecl *ForwardDecl = cast<ObjCInterfaceDecl>(D[i]);
    if (i == 0) {
      typedefString += "// @class ";
      typedefString += ForwardDecl->getNameAsString();
      typedefString += ";\n";
    }
    RewriteOneForwardClassDecl(ForwardDecl, typedefString);
  }
  RewriteForwardClassEpilogue(cast<ObjCInterfaceDecl>(D[0]), typedefString);
}

void RewriteModernObjC::RewriteMethodDeclaration(ObjCMethodDecl *Method) {
  // When method is a synthesized one, such as a getter/setter there is
  // nothing to rewrite.
  if (Method->isImplicit())
    return;
  SourceLocation LocStart = Method->getLocStart();
  SourceLocation LocEnd = Method->getLocEnd();

  if (SM->getExpansionLineNumber(LocEnd) >
      SM->getExpansionLineNumber(LocStart)) {
    InsertText(LocStart, "#if 0\n");
    ReplaceText(LocEnd, 1, ";\n#endif\n");
  } else {
    InsertText(LocStart, "// ");
  }
}

void RewriteModernObjC::RewriteProperty(ObjCPropertyDecl *prop) {
  SourceLocation Loc = prop->getAtLoc();

  ReplaceText(Loc, 0, "// ");
  // FIXME: handle properties that are declared across multiple lines.
}

void RewriteModernObjC::RewriteCategoryDecl(ObjCCategoryDecl *CatDecl) {
  SourceLocation LocStart = CatDecl->getLocStart();

  // FIXME: handle category headers that are declared across multiple lines.
  if (CatDecl->getIvarRBraceLoc().isValid()) {
    ReplaceText(LocStart, 1, "/** ");
    ReplaceText(CatDecl->getIvarRBraceLoc(), 1, "**/ ");
  }
  else {
    ReplaceText(LocStart, 0, "// ");
  }
  
  for (ObjCCategoryDecl::prop_iterator I = CatDecl->prop_begin(),
       E = CatDecl->prop_end(); I != E; ++I)
    RewriteProperty(*I);
  
  for (ObjCCategoryDecl::instmeth_iterator
         I = CatDecl->instmeth_begin(), E = CatDecl->instmeth_end();
       I != E; ++I)
    RewriteMethodDeclaration(*I);
  for (ObjCCategoryDecl::classmeth_iterator
         I = CatDecl->classmeth_begin(), E = CatDecl->classmeth_end();
       I != E; ++I)
    RewriteMethodDeclaration(*I);

  // Lastly, comment out the @end.
  ReplaceText(CatDecl->getAtEndRange().getBegin(), 
              strlen("@end"), "/* @end */");
}

void RewriteModernObjC::RewriteProtocolDecl(ObjCProtocolDecl *PDecl) {
  SourceLocation LocStart = PDecl->getLocStart();
  assert(PDecl->isThisDeclarationADefinition());
  
  // FIXME: handle protocol headers that are declared across multiple lines.
  ReplaceText(LocStart, 0, "// ");

  for (ObjCProtocolDecl::instmeth_iterator
         I = PDecl->instmeth_begin(), E = PDecl->instmeth_end();
       I != E; ++I)
    RewriteMethodDeclaration(*I);
  for (ObjCProtocolDecl::classmeth_iterator
         I = PDecl->classmeth_begin(), E = PDecl->classmeth_end();
       I != E; ++I)
    RewriteMethodDeclaration(*I);

  for (ObjCInterfaceDecl::prop_iterator I = PDecl->prop_begin(),
       E = PDecl->prop_end(); I != E; ++I)
    RewriteProperty(*I);
  
  // Lastly, comment out the @end.
  SourceLocation LocEnd = PDecl->getAtEndRange().getBegin();
  ReplaceText(LocEnd, strlen("@end"), "/* @end */");

  // Must comment out @optional/@required
  const char *startBuf = SM->getCharacterData(LocStart);
  const char *endBuf = SM->getCharacterData(LocEnd);
  for (const char *p = startBuf; p < endBuf; p++) {
    if (*p == '@' && !strncmp(p+1, "optional", strlen("optional"))) {
      SourceLocation OptionalLoc = LocStart.getLocWithOffset(p-startBuf);
      ReplaceText(OptionalLoc, strlen("@optional"), "/* @optional */");

    }
    else if (*p == '@' && !strncmp(p+1, "required", strlen("required"))) {
      SourceLocation OptionalLoc = LocStart.getLocWithOffset(p-startBuf);
      ReplaceText(OptionalLoc, strlen("@required"), "/* @required */");

    }
  }
}

void RewriteModernObjC::RewriteForwardProtocolDecl(DeclGroupRef D) {
  SourceLocation LocStart = (*D.begin())->getLocStart();
  if (LocStart.isInvalid())
    llvm_unreachable("Invalid SourceLocation");
  // FIXME: handle forward protocol that are declared across multiple lines.
  ReplaceText(LocStart, 0, "// ");
}

void 
RewriteModernObjC::RewriteForwardProtocolDecl(const llvm::SmallVector<Decl*, 8> &DG) {
  SourceLocation LocStart = DG[0]->getLocStart();
  if (LocStart.isInvalid())
    llvm_unreachable("Invalid SourceLocation");
  // FIXME: handle forward protocol that are declared across multiple lines.
  ReplaceText(LocStart, 0, "// ");
}

void 
RewriteModernObjC::RewriteLinkageSpec(LinkageSpecDecl *LSD) {
  SourceLocation LocStart = LSD->getExternLoc();
  if (LocStart.isInvalid())
    llvm_unreachable("Invalid extern SourceLocation");
  
  ReplaceText(LocStart, 0, "// ");
  if (!LSD->hasBraces())
    return;
  // FIXME. We don't rewrite well if '{' is not on same line as 'extern'.
  SourceLocation LocRBrace = LSD->getRBraceLoc();
  if (LocRBrace.isInvalid())
    llvm_unreachable("Invalid rbrace SourceLocation");
  ReplaceText(LocRBrace, 0, "// ");
}

void RewriteModernObjC::RewriteTypeIntoString(QualType T, std::string &ResultStr,
                                        const FunctionType *&FPRetType) {
  if (T->isObjCQualifiedIdType())
    ResultStr += "id";
  else if (T->isFunctionPointerType() ||
           T->isBlockPointerType()) {
    // needs special handling, since pointer-to-functions have special
    // syntax (where a decaration models use).
    QualType retType = T;
    QualType PointeeTy;
    if (const PointerType* PT = retType->getAs<PointerType>())
      PointeeTy = PT->getPointeeType();
    else if (const BlockPointerType *BPT = retType->getAs<BlockPointerType>())
      PointeeTy = BPT->getPointeeType();
    if ((FPRetType = PointeeTy->getAs<FunctionType>())) {
      ResultStr += FPRetType->getResultType().getAsString(
        Context->getPrintingPolicy());
      ResultStr += "(*";
    }
  } else
    ResultStr += T.getAsString(Context->getPrintingPolicy());
}

void RewriteModernObjC::RewriteObjCMethodDecl(const ObjCInterfaceDecl *IDecl,
                                        ObjCMethodDecl *OMD,
                                        std::string &ResultStr) {
  //fprintf(stderr,"In RewriteObjCMethodDecl\n");
  const FunctionType *FPRetType = 0;
  ResultStr += "\nstatic ";
  RewriteTypeIntoString(OMD->getResultType(), ResultStr, FPRetType);
  ResultStr += " ";

  // Unique method name
  std::string NameStr;

  if (OMD->isInstanceMethod())
    NameStr += "_I_";
  else
    NameStr += "_C_";

  NameStr += IDecl->getNameAsString();
  NameStr += "_";

  if (ObjCCategoryImplDecl *CID =
      dyn_cast<ObjCCategoryImplDecl>(OMD->getDeclContext())) {
    NameStr += CID->getNameAsString();
    NameStr += "_";
  }
  // Append selector names, replacing ':' with '_'
  {
    std::string selString = OMD->getSelector().getAsString();
    int len = selString.size();
    for (int i = 0; i < len; i++)
      if (selString[i] == ':')
        selString[i] = '_';
    NameStr += selString;
  }
  // Remember this name for metadata emission
  MethodInternalNames[OMD] = NameStr;
  ResultStr += NameStr;

  // Rewrite arguments
  ResultStr += "(";

  // invisible arguments
  if (OMD->isInstanceMethod()) {
    QualType selfTy = Context->getObjCInterfaceType(IDecl);
    selfTy = Context->getPointerType(selfTy);
    if (!LangOpts.MicrosoftExt) {
      if (ObjCSynthesizedStructs.count(const_cast<ObjCInterfaceDecl*>(IDecl)))
        ResultStr += "struct ";
    }
    // When rewriting for Microsoft, explicitly omit the structure name.
    ResultStr += IDecl->getNameAsString();
    ResultStr += " *";
  }
  else
    ResultStr += Context->getObjCClassType().getAsString(
      Context->getPrintingPolicy());

  ResultStr += " self, ";
  ResultStr += Context->getObjCSelType().getAsString(Context->getPrintingPolicy());
  ResultStr += " _cmd";

  // Method arguments.
  for (ObjCMethodDecl::param_iterator PI = OMD->param_begin(),
       E = OMD->param_end(); PI != E; ++PI) {
    ParmVarDecl *PDecl = *PI;
    ResultStr += ", ";
    if (PDecl->getType()->isObjCQualifiedIdType()) {
      ResultStr += "id ";
      ResultStr += PDecl->getNameAsString();
    } else {
      std::string Name = PDecl->getNameAsString();
      QualType QT = PDecl->getType();
      // Make sure we convert "t (^)(...)" to "t (*)(...)".
      (void)convertBlockPointerToFunctionPointer(QT);
      QT.getAsStringInternal(Name, Context->getPrintingPolicy());
      ResultStr += Name;
    }
  }
  if (OMD->isVariadic())
    ResultStr += "…