//===- ELFReader.h --------------------------------------------------------===//
//
//                     The MCLinker Project
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
#ifndef MCLD_ELF_READER_H
#define MCLD_ELF_READER_H
#ifdef ENABLE_UNITTEST
#include <gtest.h>
#endif

#include <llvm/ADT/StringRef.h>
#include <llvm/Support/ELF.h>
#include <llvm/Support/Host.h>

#include <mcld/LD/ELFReaderIf.h>
#include <mcld/LD/ResolveInfo.h>
#include <mcld/Target/GNULDBackend.h>
#include <mcld/Support/MemoryRegion.h>
#include <mcld/Support/MemoryArea.h>

namespace mcld {

//class Module;
class IRBuilder;
class SectionData;
class LDSection;

/** \class ELFReader
 *  \brief ELFReader is a template scaffolding for partial specification.
 */
template<size_t BIT, bool LITTLEENDIAN>
class ELFReader
{ };

/** \class ELFReader<32, true>
 *  \brief ELFReader<32, true> is a 32-bit, little endian ELFReader.
 */
template<>
class ELFReader<32, true> : public ELFReaderIF
{
public:
  typedef llvm::ELF::Elf32_Ehdr ELFHeader;
  typedef llvm::ELF::Elf32_Shdr SectionHeader;
  typedef llvm::ELF::Elf32_Sym  Symbol;
  typedef llvm::ELF::Elf32_Rel  Rel;
  typedef llvm::ELF::Elf32_Rela Rela;

public:
  ELFReader(GNULDBackend& pBackend);

  ~ELFReader();

  /// ELFHeaderSize - return the size of the ELFHeader
  size_t getELFHeaderSize() const
  { return sizeof(ELFHeader); }

  /// isELF - is this a ELF file
  bool isELF(void* pELFHeader) const;

  /// isMyEndian - is this ELF file in the same endian to me?
  bool isMyEndian(void* pELFHeader) const;

  /// isMyMachine - is this ELF file generated for the same machine.
  bool isMyMachine(void* pELFHeader) const;

  /// fileType - the file type of this file
  Input::Type fileType(void* pELFHeader) const;

  /// readSectionHeaders - read ELF section header table and create LDSections
  bool readSectionHeaders(Input& pInput, void* pELFHeader) const;

  /// readRegularSection - read a regular section and create fragments.
  bool readRegularSection(Input& pInput, SectionData& pSD) const;

  /// readSymbols - read ELF symbols and create LDSymbol
  bool readSymbols(Input& pInput,
                   IRBuilder& pBuilder,
                   const MemoryRegion& pRegion,
                   const char* StrTab) const;

  /// readSignature - read a symbol from the given Input and index in symtab
  /// This is used to get the signature of a group section.
  ResolveInfo* readSignature(Input& pInput,
                                    LDSection& pSymTab,
                                    uint32_t pSymIdx) const;

  /// readRela - read ELF rela and create Relocation
  bool readRela(Input& pInput,
                LDSection& pSection,
                const MemoryRegion& pRegion) const;

  /// readRel - read ELF rel and create Relocation
  bool readRel(Input& pInput,
               LDSection& pSection,
               const MemoryRegion& pRegion) const;

  /// readDynamic - read ELF .dynamic in input dynobj
  bool readDynamic(Input& pInput) const;
};


/** \class ELFReader<64, true>
 *  \brief ELFReader<64, true> is a 64-bit, little endian ELFReader.
 */
template<>
class ELFReader<64, true> : public ELFReaderIF
{
public:
  typedef llvm::ELF::Elf64_Ehdr ELFHeader;
  typedef llvm::ELF::Elf64_Shdr SectionHeader;
  typedef llvm::ELF::Elf64_Sym  Symbol;
  typedef llvm::ELF::Elf64_Rel  Rel;
  typedef llvm::ELF::Elf64_Rela Rela;

public:
  ELFReader(GNULDBackend& pBackend);

  ~ELFReader();

  /// ELFHeaderSize - return the size of the ELFHeader
  size_t getELFHeaderSize() const
  { return sizeof(ELFHeader); }

  /// isELF - is this a ELF file
  bool isELF(void* pELFHeader) const;

  /// isMyEndian - is this ELF file in the same endian to me?
  bool isMyEndian(void* pELFHeader) const;

  /// isMyMachine - is this ELF file generated for the same machine.
  bool isMyMachine(void* pELFHeader) const;

  /// fileType - the file type of this file
  Input::Type fileType(void* pELFHeader) const;

  /// readSectionHeaders - read ELF section header table and create LDSections
  bool readSectionHeaders(Input& pInput, void* pELFHeader) const;

  /// readRegularSection - read a regular section and create fragments.
  bool readRegularSection(Input& pInput, SectionData& pSD) const;

  /// readSymbols - read ELF symbols and create LDSymbol
  bool readSymbols(Input& pInput,
                   IRBuilder& pBuilder,
                   const MemoryRegion& pRegion,
                   const char* StrTab) const;

  /// readSignature - read a symbol from the given Input and index in symtab
  /// This is used to get the signature of a group section.
  ResolveInfo* readSignature(Input& pInput,
                                    LDSection& pSymTab,
                                    uint32_t pSymIdx) const;

  /// readRela - read ELF rela and create Relocation
  bool readRela(Input& pInput,
                LDSection& pSection,
                const MemoryRegion& pRegion) const;

  /// readRel - read ELF rel and create Relocation
  bool readRel(Input& pInput,
               LDSection& pSection,
               const MemoryRegion& pRegion) const;

  /// readDynamic - read ELF .dynamic in input dynobj
  bool readDynamic(Input& pInput) const;
};

} // namespace of mcld

#endif