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//===- MipsLDBackend.h ----------------------------------------------------===//
//
// The MCLinker Project
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
#ifndef MIPS_LDBACKEND_H
#define MIPS_LDBACKEND_H
#include "mcld/Target/GNULDBackend.h"
#include "MipsELFDynamic.h"
#include "MipsGOT.h"
namespace mcld {
class MCLinker;
class OutputRelocSection;
class SectionMap;
//===----------------------------------------------------------------------===//
/// MipsGNULDBackend - linker backend of Mips target of GNU ELF format
///
class MipsGNULDBackend : public GNULDBackend
{
public:
enum ReservedEntryType {
None = 0, // no reserved entry
ReserveRel = 1, // reserve a dynamic relocation entry
ReserveGot = 2, // reserve a GOT entry
ReserveGpDisp = 8 // reserve _gp_disp symbol
};
public:
MipsGNULDBackend();
~MipsGNULDBackend();
public:
/// initTargetSectionMap - initialize target dependent section mapping.
bool initTargetSectionMap(SectionMap& pSectionMap);
/// initTargetSections - initialize target dependent sections in output
void initTargetSections(MCLinker& pLinker);
/// initTargetSymbols - initialize target dependent symbols in output.
void initTargetSymbols(MCLinker& pLinker);
/// initRelocFactory - create and initialize RelocationFactory.
bool initRelocFactory(const MCLinker& pLinker);
/// getRelocFactory - return relocation factory.
RelocationFactory* getRelocFactory();
/// scanRelocation - determine the empty entries are needed or not and
/// create the empty entries if needed.
/// For Mips, the GOT, GP, and dynamic relocation entries are check to create.
void scanRelocation(Relocation& pReloc,
const LDSymbol& pInputSym,
MCLinker& pLinker,
const MCLDInfo& pLDInfo,
const Output& pOutput);
uint32_t machine() const;
/// OSABI - the value of e_ident[EI_OSABI]
uint8_t OSABI() const;
/// ABIVersion - the value of e_ident[EI_ABIVRESION]
uint8_t ABIVersion() const;
/// flags - the value of ElfXX_Ehdr::e_flags
uint64_t flags() const;
bool isLittleEndian() const;
unsigned int bitclass() const;
/// preLayout - Backend can do any needed modification before layout
void doPreLayout(const Output& pOutput,
const MCLDInfo& pInfo,
MCLinker& pLinker);
/// postLayout -Backend can do any needed modification after layout
void doPostLayout(const Output& pOutput,
const MCLDInfo& pInfo,
MCLinker& pLinker);
/// dynamic - the dynamic section of the target machine.
/// Use co-variant return type to return its own dynamic section.
MipsELFDynamic& dynamic();
/// dynamic - the dynamic section of the target machine.
/// Use co-variant return type to return its own dynamic section.
const MipsELFDynamic& 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 pOutput - the output file
/// @param pSection - the given LDSection
/// @param pInfo - all options in the command line.
/// @param pRegion - the region to write out data
/// @return the size of the table in the file.
uint64_t emitSectionData(const Output& pOutput,
const LDSection& pSection,
const MCLDInfo& pInfo,
MemoryRegion& pRegion) const;
/// emitNamePools - emit dynamic name pools - .dyntab, .dynstr, .hash
virtual void emitDynNamePools(Output& pOutput,
SymbolCategory& pSymbols,
const Layout& pLayout,
const MCLDInfo& pLDInfo);
MipsGOT& getGOT();
const MipsGOT& getGOT() const;
OutputRelocSection& getRelDyn();
const OutputRelocSection& getRelDyn() const;
/// getTargetSectionOrder - compute the layout order of ARM target sections
unsigned int getTargetSectionOrder(const Output& pOutput,
const LDSection& pSectHdr) const;
/// finalizeSymbol - finalize the symbol value
/// If the symbol's reserved field is not zero, MCLinker will call back this
/// function to ask the final value of the symbol
bool finalizeSymbol(LDSymbol& pSymbol) const;
/// allocateCommonSymbols - allocate common symbols in the corresponding
/// sections.
bool allocateCommonSymbols(const MCLDInfo& pLDInfo, MCLinker& pLinker) const;
private:
void scanLocalReloc(Relocation& pReloc,
const LDSymbol& pInputSym,
MCLinker& pLinker,
const MCLDInfo& pLDInfo,
const Output& pOutput);
void scanGlobalReloc(Relocation& pReloc,
const LDSymbol& pInputSym,
MCLinker& pLinker,
const MCLDInfo& pLDInfo,
const Output& pOutput);
bool isSymbolNeedsPLT(ResolveInfo& pSym, const Output& pOutput) const;
bool isSymbolNeedsDynRel(ResolveInfo& pSym, const Output& pOutput) const;
void createGOT(MCLinker& pLinker, const Output& pOutput);
void createRelDyn(MCLinker& pLinker, const Output& pOutput);
ELFFileFormat* getOutputFormat(const Output& pOutput) const;
/// updateAddend - update addend value of the relocation if the
/// the target symbol is a section symbol. Addend is the offset
/// in the section. This value should be updated after section
/// merged.
void updateAddend(Relocation& pReloc,
const LDSymbol& pInputSym,
const Layout& pLayout) const;
private:
RelocationFactory* m_pRelocFactory;
MipsGOT* m_pGOT; // .got
OutputRelocSection* m_pRelDyn; // .rel.dyn
MipsELFDynamic* m_pDynamic;
LDSymbol* m_pGOTSymbol;
LDSymbol* m_pGpDispSymbol;
std::vector<LDSymbol*> m_LocalGOTSyms;
std::vector<LDSymbol*> m_GlobalGOTSyms;
private:
/// isGOTSymbol - return true if the symbol is the GOT entry.
bool isGOTSymbol(const LDSymbol& pSymbol) const;
/// emitDynamicSymbol - emit dynamic symbol.
void emitDynamicSymbol(llvm::ELF::Elf32_Sym& sym32,
Output& pOutput,
LDSymbol& pSymbol,
const Layout& pLayout,
char* strtab,
size_t strtabsize,
size_t symtabIdx);
};
} // namespace of mcld
#endif