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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 TARGET_MIPS_MIPSLDBACKEND_H_
#define TARGET_MIPS_MIPSLDBACKEND_H_
#include <llvm/Support/ELF.h>
#include "mcld/Target/GNULDBackend.h"
#include "MipsAbiFlags.h"
#include "MipsELFDynamic.h"
#include "MipsGOT.h"
#include "MipsGOTPLT.h"
#include "MipsPLT.h"
namespace mcld {
class LinkerConfig;
class MemoryArea;
class MipsGNUInfo;
class OutputRelocSection;
class SectionMap;
/** \class MipsGNULDBackend
* \brief Base linker backend of Mips target of GNU ELF format.
*/
class MipsGNULDBackend : public GNULDBackend {
public:
typedef std::vector<LDSymbol*> SymbolListType;
public:
MipsGNULDBackend(const LinkerConfig& pConfig, MipsGNUInfo* pInfo);
~MipsGNULDBackend();
bool needsLA25Stub(Relocation::Type pType, const mcld::ResolveInfo* pSym);
void addNonPICBranchSym(ResolveInfo* rsym);
bool hasNonPICBranch(const ResolveInfo* rsym) const;
public:
/// initTargetSections - initialize target dependent sections in output
void initTargetSections(Module& pModule, ObjectBuilder& pBuilder);
/// initTargetSymbols - initialize target dependent symbols in output.
void initTargetSymbols(IRBuilder& pBuilder, Module& pModule);
/// getRelocator - return relocator.
const Relocator* getRelocator() const;
Relocator* getRelocator();
/// 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.
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 SectionData 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 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;
/// hasEntryInStrTab - symbol has an entry in a .strtab
bool hasEntryInStrTab(const LDSymbol& pSym) const;
/// orderSymbolTable - order symbol table before emitting
void orderSymbolTable(Module& pModule);
/// readSection - read a target dependent section.
bool readSection(Input& pInput, SectionData& pSD);
MipsGOT& getGOT();
const MipsGOT& getGOT() const;
MipsPLT& getPLT();
const MipsPLT& getPLT() const;
MipsGOTPLT& getGOTPLT();
const MipsGOTPLT& getGOTPLT() const;
OutputRelocSection& getRelPLT();
const OutputRelocSection& getRelPLT() const;
OutputRelocSection& getRelDyn();
const OutputRelocSection& getRelDyn() const;
LDSymbol* getGOTSymbol() { return m_pGOTSymbol; }
const LDSymbol* getGOTSymbol() const { return m_pGOTSymbol; }
LDSymbol* getGpDispSymbol() { return m_pGpDispSymbol; }
const LDSymbol* getGpDispSymbol() const { return m_pGpDispSymbol; }
SymbolListType& getGlobalGOTSyms() { return m_GlobalGOTSyms; }
const SymbolListType& getGlobalGOTSyms() const { return m_GlobalGOTSyms; }
/// getTargetSectionOrder - compute the layout order of ARM target sections
unsigned int getTargetSectionOrder(const LDSection& pSectHdr) const;
/// finalizeSymbol - finalize the symbol value
bool finalizeTargetSymbols();
/// allocateCommonSymbols - allocate common symbols in the corresponding
/// sections.
bool allocateCommonSymbols(Module& pModule);
/// getTPOffset - return TP_OFFSET against the SHF_TLS
/// section in the specified input.
uint64_t getTPOffset(const Input& pInput) const;
/// getDTPOffset - return DTP_OFFSET against the SHF_TLS
/// section in the specified input.
uint64_t getDTPOffset(const Input& pInput) const;
/// getGP0 - the gp value used to create the relocatable objects
/// in the specified input.
uint64_t getGP0(const Input& pInput) const;
private:
void defineGOTSymbol(IRBuilder& pBuilder);
void defineGOTPLTSymbol(IRBuilder& pBuilder);
bool relaxRelocation(IRBuilder& pBuilder, Relocation& pRel);
/// emitSymbol32 - emit an ELF32 symbol, override parent's function
void emitSymbol32(llvm::ELF::Elf32_Sym& pSym32,
LDSymbol& pSymbol,
char* pStrtab,
size_t pStrtabsize,
size_t pSymtabIdx);
/// doCreateProgramHdrs - backend can implement this function to create the
/// target-dependent segments
void doCreateProgramHdrs(Module& pModule);
/// mayRelax - Backends should override this function if they need relaxation
bool mayRelax() { return true; }
/// doRelax - Backend can orevride this function to add its relaxation
/// implementation. Return true if the output (e.g., .text) is "relaxed"
/// (i.e. layout is changed), and set pFinished to true if everything is fit,
/// otherwise set it to false.
bool doRelax(Module& pModule, IRBuilder& pBuilder, bool& pFinished);
/// initTargetStubs
bool initTargetStubs();
/// readRelocation - read ELF32_Rel entry
bool readRelocation(const llvm::ELF::Elf32_Rel& pRel,
Relocation::Type& pType,
uint32_t& pSymIdx,
uint32_t& pOffset) const;
/// readRelocation - read ELF32_Rela entry
bool readRelocation(const llvm::ELF::Elf32_Rela& pRel,
Relocation::Type& pType,
uint32_t& pSymIdx,
uint32_t& pOffset,
int32_t& pAddend) const;
/// readRelocation - read ELF64_Rel entry
bool readRelocation(const llvm::ELF::Elf64_Rel& pRel,
Relocation::Type& pType,
uint32_t& pSymIdx,
uint64_t& pOffset) const;
/// readRel - read ELF64_Rela entry
bool readRelocation(const llvm::ELF::Elf64_Rela& pRel,
Relocation::Type& pType,
uint32_t& pSymIdx,
uint64_t& pOffset,
int64_t& pAddend) const;
/// emitRelocation - write data to the ELF32_Rel entry
void emitRelocation(llvm::ELF::Elf32_Rel& pRel,
Relocation::Type pType,
uint32_t pSymIdx,
uint32_t pOffset) const;
/// emitRelocation - write data to the ELF32_Rela entry
void emitRelocation(llvm::ELF::Elf32_Rela& pRel,
Relocation::Type pType,
uint32_t pSymIdx,
uint32_t pOffset,
int32_t pAddend) const;
/// emitRelocation - write data to the ELF64_Rel entry
void emitRelocation(llvm::ELF::Elf64_Rel& pRel,
Relocation::Type pType,
uint32_t pSymIdx,
uint64_t pOffset) const;
/// emitRelocation - write data to the ELF64_Rela entry
void emitRelocation(llvm::ELF::Elf64_Rela& pRel,
Relocation::Type pType,
uint32_t pSymIdx,
uint64_t pOffset,
int64_t pAddend) const;
/// preMergeSections - hooks to be executed before merging sections
void preMergeSections(Module& pModule);
/// mergeSection - merge target dependent sections
bool mergeSection(Module& pModule, const Input& pInput, LDSection& pSection);
protected:
virtual void mergeFlags(Input& pInput, const char* ELF_hdr);
private:
typedef llvm::DenseSet<const ResolveInfo*> ResolveInfoSetType;
typedef llvm::DenseMap<const Input*, llvm::ELF::Elf64_Addr> InputNumMapType;
typedef llvm::DenseMap<const Input*, uint64_t> ElfFlagsMapType;
protected:
Relocator* m_pRelocator;
MipsGOT* m_pGOT; // .got
MipsPLT* m_pPLT; // .plt
MipsGOTPLT* m_pGOTPLT; // .got.plt
private:
MipsGNUInfo& m_pInfo;
llvm::Optional<MipsAbiFlags> m_pAbiInfo;
OutputRelocSection* m_pRelPlt; // .rel.plt
OutputRelocSection* m_pRelDyn; // .rel.dyn
MipsELFDynamic* m_pDynamic;
LDSection* m_psdata;
LDSection* m_pAbiFlags;
LDSymbol* m_pGOTSymbol;
LDSymbol* m_pPLTSymbol;
LDSymbol* m_pGpDispSymbol;
SymbolListType m_GlobalGOTSyms;
ResolveInfoSetType m_HasNonPICBranchSyms;
InputNumMapType m_GP0Map;
InputNumMapType m_TpOffsetMap;
InputNumMapType m_DtpOffsetMap;
ElfFlagsMapType m_ElfFlagsMap;
void moveSectionData(SectionData& pFrom, SectionData& pTo);
void saveTPOffset(const Input& pInput);
};
/** \class Mips32GNULDBackend
* \brief Base linker backend of Mips 32-bit target of GNU ELF format.
*/
class Mips32GNULDBackend : public MipsGNULDBackend {
public:
Mips32GNULDBackend(const LinkerConfig& pConfig, MipsGNUInfo* pInfo);
private:
// MipsGNULDBackend
bool initRelocator();
void initTargetSections(Module& pModule, ObjectBuilder& pBuilder);
size_t getRelEntrySize();
size_t getRelaEntrySize();
};
/** \class Mips64GNULDBackend
* \brief Base linker backend of Mips 64-bit target of GNU ELF format.
*/
class Mips64GNULDBackend : public MipsGNULDBackend {
public:
Mips64GNULDBackend(const LinkerConfig& pConfig, MipsGNUInfo* pInfo);
private:
// MipsGNULDBackend
bool initRelocator();
void initTargetSections(Module& pModule, ObjectBuilder& pBuilder);
size_t getRelEntrySize();
size_t getRelaEntrySize();
};
} // namespace mcld
#endif // TARGET_MIPS_MIPSLDBACKEND_H_