lib/Target/X86/X86LDBackend.h

//===- X86LDBackend.h -----------------------------------------------------===//
//
//                     The MCLinker Project
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
#ifndef TARGET_X86_X86LDBACKEND_H_
#define TARGET_X86_X86LDBACKEND_H_

#include "X86ELFDynamic.h"
#include "X86GOT.h"
#include "X86GOTPLT.h"
#include "X86PLT.h"

#include "mcld/LD/LDSection.h"
#include "mcld/Target/GNULDBackend.h"
#include "mcld/Target/OutputRelocSection.h"

namespace mcld {

class LinkerConfig;
class GNUInfo;

//===----------------------------------------------------------------------===//
/// X86GNULDBackend - linker backend of X86 target of GNU ELF format
///
class X86GNULDBackend : public GNULDBackend {
 public:
  X86GNULDBackend(const LinkerConfig& pConfig,
                  GNUInfo* pInfo,
                  Relocation::Type pCopyRel);

  ~X86GNULDBackend();

  uint32_t machine() const;

  X86PLT& getPLT();

  const X86PLT& getPLT() const;

  /// preLayout - Backend can do any needed modification before layout
  void doPreLayout(IRBuilder& pBuilder);

  /// postLayout -Backend can do any needed modification after layout
  void doPostLayout(Module& pModule, IRBuilder& pBuilder);

  /// dynamic - the dynamic section of the target machine.
  /// Use co-variant return type to return its own dynamic section.
  X86ELFDynamic& dynamic();

  /// dynamic - the dynamic section of the target machine.
  /// Use co-variant return type to return its own dynamic section.
  const X86ELFDynamic& dynamic() const;

  /// emitSectionData - write out the section data into the memory region.
  /// When writers get a LDSection whose kind is LDFileFormat::Target, writers
  /// call back target backend to emit the data.
  ///
  /// Backends handle the target-special tables (plt, gp,...) by themselves.
  /// Backend can put the data of the tables in MCSectionData directly
  ///  - LDSection.getSectionData can get the section data.
  /// Or, backend can put the data into special data structure
  ///  - backend can maintain its own map<LDSection, table> to get the table
  /// from given LDSection.
  ///
  /// @param pSection - the given LDSection
  /// @param pLayout - for comouting the size of fragment
  /// @param pRegion - the region to write out data
  /// @return the size of the table in the file.
  uint64_t emitSectionData(const LDSection& pSection,
                           MemoryRegion& pRegion) const;

  /// initRelocator - create and initialize Relocator.
  virtual bool initRelocator() = 0;

  /// getRelocator - return relocator.
  const Relocator* getRelocator() const;
  Relocator* getRelocator();

  virtual void initTargetSections(Module& pModule, ObjectBuilder& pBuilder) = 0;

  void initTargetSymbols(IRBuilder& pBuilder, Module& pModule);

  OutputRelocSection& getRelDyn();
  const OutputRelocSection& getRelDyn() const;

  OutputRelocSection& getRelPLT();
  const OutputRelocSection& getRelPLT() const;

  LDSymbol* getGOTSymbol() { return m_pGOTSymbol; }
  const LDSymbol* getGOTSymbol() const { return m_pGOTSymbol; }

  /// getTargetSectionOrder - compute the layout order of X86 target sections
  unsigned int getTargetSectionOrder(const LDSection& pSectHdr) const;

  /// finalizeTargetSymbols - finalize the symbol value
  bool finalizeTargetSymbols();

  /// getPointerRel - get pointer relocation type.
  Relocation::Type getPointerRel() { return m_PointerRel; }

  Relocation::Type getCopyRelType() const { return m_CopyRel; }
  Relocation::Type getPointerRelType() const { return m_PointerRel; }

 protected:
  void defineGOTSymbol(IRBuilder& pBuilder, Fragment&);

  /// getRelEntrySize - the size in BYTE of rel type relocation
  size_t getRelEntrySize() { return m_RelEntrySize; }

  /// getRelEntrySize - the size in BYTE of rela type relocation
  size_t getRelaEntrySize() { return m_RelaEntrySize; }

 private:
  /// doCreateProgramHdrs - backend can implement this function to create the
  /// target-dependent segments
  void doCreateProgramHdrs(Module& pModule);

  virtual void setGOTSectionSize(IRBuilder& pBuilder) = 0;

  virtual uint64_t emitGOTSectionData(MemoryRegion& pRegion) const = 0;

  virtual uint64_t emitGOTPLTSectionData(
      MemoryRegion& pRegion,
      const ELFFileFormat* FileFormat) const = 0;

  virtual void setRelDynSize() = 0;
  virtual void setRelPLTSize() = 0;

  void addEhFrameForPLT(Module& pModule);
  virtual llvm::StringRef createCIERegionForPLT() = 0;
  virtual llvm::StringRef createFDERegionForPLT() = 0;

 protected:
  Relocator* m_pRelocator;
  X86PLT* m_pPLT;
  /// m_RelDyn - dynamic relocation table of .rel.dyn
  OutputRelocSection* m_pRelDyn;
  /// m_RelPLT - dynamic relocation table of .rel.plt
  OutputRelocSection* m_pRelPLT;

  X86ELFDynamic* m_pDynamic;
  LDSymbol* m_pGOTSymbol;

  size_t m_RelEntrySize;
  size_t m_RelaEntrySize;

  Relocation::Type m_CopyRel;
  Relocation::Type m_PointerRel;
};

//
//===----------------------------------------------------------------------===//
/// X86_32GNULDBackend - linker backend of X86-32 target of GNU ELF format
///
class X86_32GNULDBackend : public X86GNULDBackend {
 public:
  X86_32GNULDBackend(const LinkerConfig& pConfig, GNUInfo* pInfo);

  ~X86_32GNULDBackend();

  void initTargetSections(Module& pModule, ObjectBuilder& pBuilder);

  X86_32GOT& getGOT();

  const X86_32GOT& getGOT() const;

  X86_32GOTPLT& getGOTPLT();

  const X86_32GOTPLT& getGOTPLT() const;

 private:
  /// initRelocator - create and initialize Relocator.
  bool initRelocator();

  void setGOTSectionSize(IRBuilder& pBuilder);

  uint64_t emitGOTSectionData(MemoryRegion& pRegion) const;

  uint64_t emitGOTPLTSectionData(MemoryRegion& pRegion,
                                 const ELFFileFormat* FileFormat) const;

  void setRelDynSize();
  void setRelPLTSize();

  llvm::StringRef createCIERegionForPLT();
  llvm::StringRef createFDERegionForPLT();

 private:
  X86_32GOT* m_pGOT;
  X86_32GOTPLT* m_pGOTPLT;
};

//
//===----------------------------------------------------------------------===//
/// X86_64GNULDBackend - linker backend of X86-64 target of GNU ELF format
///
class X86_64GNULDBackend : public X86GNULDBackend {
 public:
  X86_64GNULDBackend(const LinkerConfig& pConfig, GNUInfo* pInfo);

  ~X86_64GNULDBackend();

  void initTargetSections(Module& pModule, ObjectBuilder& pBuilder);

  X86_64GOT& getGOT();

  const X86_64GOT& getGOT() const;

  X86_64GOTPLT& getGOTPLT();

  const X86_64GOTPLT& getGOTPLT() const;

 private:
  /// initRelocator - create and initialize Relocator.
  bool initRelocator();

  void setGOTSectionSize(IRBuilder& pBuilder);

  uint64_t emitGOTSectionData(MemoryRegion& pRegion) const;

  uint64_t emitGOTPLTSectionData(MemoryRegion& pRegion,
                                 const ELFFileFormat* FileFormat) const;

  void setRelDynSize();
  void setRelPLTSize();

  llvm::StringRef createCIERegionForPLT();
  llvm::StringRef createFDERegionForPLT();

 private:
  X86_64GOT* m_pGOT;
  X86_64GOTPLT* m_pGOTPLT;
};

}  // namespace mcld

#endif  // TARGET_X86_X86LDBACKEND_H_