llvm-mirror/lib/MC/ELFObjectWriter.h
2011-12-22 00:37:50 +00:00

416 lines
15 KiB
C++

//===- lib/MC/ELFObjectWriter.h - ELF File Writer -------------------------===//
//
// 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 object file writer information.
//
//===----------------------------------------------------------------------===//
#ifndef LLVM_MC_ELFOBJECTWRITER_H
#define LLVM_MC_ELFOBJECTWRITER_H
#include "MCELF.h"
#include "llvm/ADT/OwningPtr.h"
#include "llvm/ADT/SmallPtrSet.h"
#include "llvm/ADT/SmallString.h"
#include "llvm/ADT/STLExtras.h"
#include "llvm/MC/MCAssembler.h"
#include "llvm/MC/MCELFObjectWriter.h"
#include "llvm/MC/MCELFSymbolFlags.h"
#include "llvm/MC/MCObjectWriter.h"
#include "llvm/MC/MCExpr.h"
#include "llvm/MC/MCSymbol.h"
#include <vector>
namespace llvm {
class MCSection;
class MCDataFragment;
class MCSectionELF;
class ELFObjectWriter : public MCObjectWriter {
protected:
static bool isFixupKindPCRel(const MCAssembler &Asm, unsigned Kind);
static bool RelocNeedsGOT(MCSymbolRefExpr::VariantKind Variant);
static uint64_t SymbolValue(MCSymbolData &Data, const MCAsmLayout &Layout);
static bool isInSymtab(const MCAssembler &Asm, const MCSymbolData &Data,
bool Used, bool Renamed);
static bool isLocal(const MCSymbolData &Data, bool isSignature,
bool isUsedInReloc);
static bool IsELFMetaDataSection(const MCSectionData &SD);
static uint64_t DataSectionSize(const MCSectionData &SD);
static uint64_t GetSectionFileSize(const MCAsmLayout &Layout,
const MCSectionData &SD);
static uint64_t GetSectionAddressSize(const MCAsmLayout &Layout,
const MCSectionData &SD);
void WriteDataSectionData(MCAssembler &Asm,
const MCAsmLayout &Layout,
const MCSectionELF &Section);
/*static bool isFixupKindX86RIPRel(unsigned Kind) {
return Kind == X86::reloc_riprel_4byte ||
Kind == X86::reloc_riprel_4byte_movq_load;
}*/
/// ELFSymbolData - Helper struct for containing some precomputed
/// information on symbols.
struct ELFSymbolData {
MCSymbolData *SymbolData;
uint64_t StringIndex;
uint32_t SectionIndex;
// Support lexicographic sorting.
bool operator<(const ELFSymbolData &RHS) const {
if (MCELF::GetType(*SymbolData) == ELF::STT_FILE)
return true;
if (MCELF::GetType(*RHS.SymbolData) == ELF::STT_FILE)
return false;
return SymbolData->getSymbol().getName() <
RHS.SymbolData->getSymbol().getName();
}
};
/// @name Relocation Data
/// @{
struct ELFRelocationEntry {
// Make these big enough for both 32-bit and 64-bit
uint64_t r_offset;
int Index;
unsigned Type;
const MCSymbol *Symbol;
uint64_t r_addend;
ELFRelocationEntry()
: r_offset(0), Index(0), Type(0), Symbol(0), r_addend(0) {}
ELFRelocationEntry(uint64_t RelocOffset, int Idx,
unsigned RelType, const MCSymbol *Sym,
uint64_t Addend)
: r_offset(RelocOffset), Index(Idx), Type(RelType),
Symbol(Sym), r_addend(Addend) {}
// Support lexicographic sorting.
bool operator<(const ELFRelocationEntry &RE) const {
return RE.r_offset < r_offset;
}
};
/// The target specific ELF writer instance.
llvm::OwningPtr<MCELFObjectTargetWriter> TargetObjectWriter;
SmallPtrSet<const MCSymbol *, 16> UsedInReloc;
SmallPtrSet<const MCSymbol *, 16> WeakrefUsedInReloc;
DenseMap<const MCSymbol *, const MCSymbol *> Renames;
llvm::DenseMap<const MCSectionData*,
std::vector<ELFRelocationEntry> > Relocations;
DenseMap<const MCSection*, uint64_t> SectionStringTableIndex;
/// @}
/// @name Symbol Table Data
/// @{
SmallString<256> StringTable;
std::vector<ELFSymbolData> LocalSymbolData;
std::vector<ELFSymbolData> ExternalSymbolData;
std::vector<ELFSymbolData> UndefinedSymbolData;
/// @}
bool NeedsGOT;
bool NeedsSymtabShndx;
// This holds the symbol table index of the last local symbol.
unsigned LastLocalSymbolIndex;
// This holds the .strtab section index.
unsigned StringTableIndex;
// This holds the .symtab section index.
unsigned SymbolTableIndex;
unsigned ShstrtabIndex;
virtual const MCSymbol *SymbolToReloc(const MCAssembler &Asm,
const MCValue &Target,
const MCFragment &F,
const MCFixup &Fixup,
bool IsPCRel) const;
// For arch-specific emission of explicit reloc symbol
virtual const MCSymbol *ExplicitRelSym(const MCAssembler &Asm,
const MCValue &Target,
const MCFragment &F,
const MCFixup &Fixup,
bool IsPCRel) const {
return TargetObjectWriter->ExplicitRelSym(Asm, Target, F, Fixup, IsPCRel);
}
bool is64Bit() const { return TargetObjectWriter->is64Bit(); }
bool hasRelocationAddend() const {
return TargetObjectWriter->hasRelocationAddend();
}
public:
ELFObjectWriter(MCELFObjectTargetWriter *MOTW,
raw_ostream &_OS, bool IsLittleEndian)
: MCObjectWriter(_OS, IsLittleEndian),
TargetObjectWriter(MOTW),
NeedsGOT(false), NeedsSymtabShndx(false){
}
virtual ~ELFObjectWriter();
void WriteWord(uint64_t W) {
if (is64Bit())
Write64(W);
else
Write32(W);
}
void StringLE16(char *buf, uint16_t Value) {
buf[0] = char(Value >> 0);
buf[1] = char(Value >> 8);
}
void StringLE32(char *buf, uint32_t Value) {
StringLE16(buf, uint16_t(Value >> 0));
StringLE16(buf + 2, uint16_t(Value >> 16));
}
void StringLE64(char *buf, uint64_t Value) {
StringLE32(buf, uint32_t(Value >> 0));
StringLE32(buf + 4, uint32_t(Value >> 32));
}
void StringBE16(char *buf ,uint16_t Value) {
buf[0] = char(Value >> 8);
buf[1] = char(Value >> 0);
}
void StringBE32(char *buf, uint32_t Value) {
StringBE16(buf, uint16_t(Value >> 16));
StringBE16(buf + 2, uint16_t(Value >> 0));
}
void StringBE64(char *buf, uint64_t Value) {
StringBE32(buf, uint32_t(Value >> 32));
StringBE32(buf + 4, uint32_t(Value >> 0));
}
void String8(MCDataFragment &F, uint8_t Value) {
char buf[1];
buf[0] = Value;
F.getContents() += StringRef(buf, 1);
}
void String16(MCDataFragment &F, uint16_t Value) {
char buf[2];
if (isLittleEndian())
StringLE16(buf, Value);
else
StringBE16(buf, Value);
F.getContents() += StringRef(buf, 2);
}
void String32(MCDataFragment &F, uint32_t Value) {
char buf[4];
if (isLittleEndian())
StringLE32(buf, Value);
else
StringBE32(buf, Value);
F.getContents() += StringRef(buf, 4);
}
void String64(MCDataFragment &F, uint64_t Value) {
char buf[8];
if (isLittleEndian())
StringLE64(buf, Value);
else
StringBE64(buf, Value);
F.getContents() += StringRef(buf, 8);
}
virtual void WriteHeader(uint64_t SectionDataSize,
unsigned NumberOfSections);
virtual unsigned getEFlags() const {
return TargetObjectWriter->getEFlags();
}
virtual void WriteSymbolEntry(MCDataFragment *SymtabF,
MCDataFragment *ShndxF,
uint64_t name, uint8_t info,
uint64_t value, uint64_t size,
uint8_t other, uint32_t shndx,
bool Reserved);
virtual void WriteSymbol(MCDataFragment *SymtabF, MCDataFragment *ShndxF,
ELFSymbolData &MSD,
const MCAsmLayout &Layout);
typedef DenseMap<const MCSectionELF*, uint32_t> SectionIndexMapTy;
virtual void WriteSymbolTable(MCDataFragment *SymtabF,
MCDataFragment *ShndxF,
const MCAssembler &Asm,
const MCAsmLayout &Layout,
const SectionIndexMapTy &SectionIndexMap);
virtual void RecordRelocation(const MCAssembler &Asm,
const MCAsmLayout &Layout,
const MCFragment *Fragment,
const MCFixup &Fixup,
MCValue Target, uint64_t &FixedValue);
virtual uint64_t getSymbolIndexInSymbolTable(const MCAssembler &Asm,
const MCSymbol *S);
// Map from a group section to the signature symbol
typedef DenseMap<const MCSectionELF*, const MCSymbol*> GroupMapTy;
// Map from a signature symbol to the group section
typedef DenseMap<const MCSymbol*, const MCSectionELF*> RevGroupMapTy;
// Map from a section to the section with the relocations
typedef DenseMap<const MCSectionELF*, const MCSectionELF*> RelMapTy;
// Map from a section to its offset
typedef DenseMap<const MCSectionELF*, uint64_t> SectionOffsetMapTy;
/// ComputeSymbolTable - Compute the symbol table data
///
/// \param StringTable [out] - The string table data.
/// \param StringIndexMap [out] - Map from symbol names to offsets in the
/// string table.
virtual void ComputeSymbolTable(MCAssembler &Asm,
const SectionIndexMapTy &SectionIndexMap,
RevGroupMapTy RevGroupMap,
unsigned NumRegularSections);
virtual void ComputeIndexMap(MCAssembler &Asm,
SectionIndexMapTy &SectionIndexMap,
const RelMapTy &RelMap);
void CreateRelocationSections(MCAssembler &Asm, MCAsmLayout &Layout,
RelMapTy &RelMap);
void WriteRelocations(MCAssembler &Asm, MCAsmLayout &Layout,
const RelMapTy &RelMap);
virtual void CreateMetadataSections(MCAssembler &Asm, MCAsmLayout &Layout,
SectionIndexMapTy &SectionIndexMap,
const RelMapTy &RelMap);
// Create the sections that show up in the symbol table. Currently
// those are the .note.GNU-stack section and the group sections.
virtual void CreateIndexedSections(MCAssembler &Asm, MCAsmLayout &Layout,
GroupMapTy &GroupMap,
RevGroupMapTy &RevGroupMap,
SectionIndexMapTy &SectionIndexMap,
const RelMapTy &RelMap);
virtual void ExecutePostLayoutBinding(MCAssembler &Asm,
const MCAsmLayout &Layout);
void WriteSectionHeader(MCAssembler &Asm, const GroupMapTy &GroupMap,
const MCAsmLayout &Layout,
const SectionIndexMapTy &SectionIndexMap,
const SectionOffsetMapTy &SectionOffsetMap);
void ComputeSectionOrder(MCAssembler &Asm,
std::vector<const MCSectionELF*> &Sections);
virtual void WriteSecHdrEntry(uint32_t Name, uint32_t Type, uint64_t Flags,
uint64_t Address, uint64_t Offset,
uint64_t Size, uint32_t Link, uint32_t Info,
uint64_t Alignment, uint64_t EntrySize);
virtual void WriteRelocationsFragment(const MCAssembler &Asm,
MCDataFragment *F,
const MCSectionData *SD);
virtual bool
IsSymbolRefDifferenceFullyResolvedImpl(const MCAssembler &Asm,
const MCSymbolData &DataA,
const MCFragment &FB,
bool InSet,
bool IsPCRel) const;
virtual void WriteObject(MCAssembler &Asm, const MCAsmLayout &Layout);
virtual void WriteSection(MCAssembler &Asm,
const SectionIndexMapTy &SectionIndexMap,
uint32_t GroupSymbolIndex,
uint64_t Offset, uint64_t Size, uint64_t Alignment,
const MCSectionELF &Section);
protected:
virtual unsigned GetRelocType(const MCValue &Target, const MCFixup &Fixup,
bool IsPCRel, bool IsRelocWithSymbol,
int64_t Addend) const;
virtual void adjustFixupOffset(const MCFixup &Fixup,
uint64_t &RelocOffset) {}
};
//===- PPCELFObjectWriter -------------------------------------------===//
class PPCELFObjectWriter : public ELFObjectWriter {
public:
PPCELFObjectWriter(MCELFObjectTargetWriter *MOTW,
raw_ostream &_OS,
bool IsLittleEndian);
virtual ~PPCELFObjectWriter();
protected:
virtual unsigned GetRelocType(const MCValue &Target, const MCFixup &Fixup,
bool IsPCRel, bool IsRelocWithSymbol,
int64_t Addend) const;
virtual void adjustFixupOffset(const MCFixup &Fixup, uint64_t &RelocOffset);
};
//===- MBlazeELFObjectWriter -------------------------------------------===//
class MBlazeELFObjectWriter : public ELFObjectWriter {
public:
MBlazeELFObjectWriter(MCELFObjectTargetWriter *MOTW,
raw_ostream &_OS,
bool IsLittleEndian);
virtual ~MBlazeELFObjectWriter();
protected:
virtual unsigned GetRelocType(const MCValue &Target, const MCFixup &Fixup,
bool IsPCRel, bool IsRelocWithSymbol,
int64_t Addend) const;
};
//===- MipsELFObjectWriter -------------------------------------------===//
class MipsELFObjectWriter : public ELFObjectWriter {
public:
MipsELFObjectWriter(MCELFObjectTargetWriter *MOTW,
raw_ostream &_OS,
bool IsLittleEndian);
virtual ~MipsELFObjectWriter();
virtual unsigned getEFlags() const;
protected:
virtual const MCSymbol *ExplicitRelSym(const MCAssembler &Asm,
const MCValue &Target,
const MCFragment &F,
const MCFixup &Fixup,
bool IsPCRel) const;
virtual unsigned GetRelocType(const MCValue &Target, const MCFixup &Fixup,
bool IsPCRel, bool IsRelocWithSymbol,
int64_t Addend) const;
};
}
#endif