lib/Target/X86/X86ELFWriterInfo.h

//===-- X86ELFWriterInfo.h - ELF Writer Info for X86 ------------*- C++ -*-===//
//
//                     The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file implements ELF writer information for the X86 backend.
//
//===----------------------------------------------------------------------===//

#ifndef X86_ELF_WRITER_INFO_H
#define X86_ELF_WRITER_INFO_H

#include "llvm/Target/TargetELFWriterInfo.h"

namespace llvm {

  class X86ELFWriterInfo : public TargetELFWriterInfo {

    // ELF Relocation types for X86
    enum X86RelocationType {
      R_386_NONE = 0,
      R_386_32   = 1,
      R_386_PC32 = 2
    };

    // ELF Relocation types for X86_64
    enum X86_64RelocationType {
      R_X86_64_NONE = 0,
      R_X86_64_64   = 1,
      R_X86_64_PC32 = 2,
      R_X86_64_32   = 10,
      R_X86_64_32S  = 11,
      R_X86_64_PC64 = 24
    };

  public:
    X86ELFWriterInfo(TargetMachine &TM);
    virtual ~X86ELFWriterInfo();

    /// getRelocationType - Returns the target specific ELF Relocation type.
    /// 'MachineRelTy' contains the object code independent relocation type
    virtual unsigned getRelocationType(unsigned MachineRelTy) const;

    /// hasRelocationAddend - True if the target uses an addend in the
    /// ELF relocation entry.
    virtual bool hasRelocationAddend() const { return is64Bit ? true : false; }

    /// hasCustomJumpTableIndexRelTy - Returns true if the target has a
    /// specific relocation type for a jump table index.
    virtual bool hasCustomJumpTableIndexRelTy() const {
      return is64Bit ? true : false;
    }

    /// getJumpTableIndexRelTy - Returns the target specific relocation type
    /// for a jump table index.
    virtual unsigned getJumpTableIndexRelTy() const { return R_X86_64_32S; }

    /// getDefaultAddendForRelTy - Gets the default addend value for a
    /// relocation entry based on the target ELF relocation type.
    virtual long int getDefaultAddendForRelTy(unsigned RelTy) const;

    /// getRelTySize - Returns the size of relocatable field in bits
    virtual unsigned getRelocationTySize(unsigned RelTy) const;

    /// isPCRelativeRel - True if the relocation type is pc relative
    virtual bool isPCRelativeRel(unsigned RelTy) const;

    /// getJumpTableRelocationTy - Returns the machine relocation type used
    /// to reference a jumptable.
    virtual unsigned getAbsoluteLabelMachineRelTy() const;

    /// computeRelocation - Some relocatable fields could be relocated
    /// directly, avoiding the relocation symbol emission, compute the
    /// final relocation value for this symbol.
    virtual long int computeRelocation(unsigned SymOffset, unsigned RelOffset,
                                       unsigned RelTy) const;
  };

} // end llvm namespace

#endif // X86_ELF_WRITER_INFO_H