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//===-- llvm/MC/MCObjectWriter.h - Object File Writer Interface -*- C++ -*-===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
#ifndef LLVM_MC_MCOBJECTWRITER_H
#define LLVM_MC_MCOBJECTWRITER_H
#include "llvm/ADT/Triple.h"
#include "llvm/Support/raw_ostream.h"
#include "llvm/System/DataTypes.h"
#include <cassert>
namespace llvm {
class MCAsmLayout;
class MCAssembler;
class MCFixup;
class MCFragment;
class MCValue;
class raw_ostream;
/// MCObjectWriter - Defines the object file and target independent interfaces
/// used by the assembler backend to write native file format object files.
///
/// The object writer contains a few callbacks used by the assembler to allow
/// the object writer to modify the assembler data structures at appropriate
/// points. Once assembly is complete, the object writer is given the
/// MCAssembler instance, which contains all the symbol and section data which
/// should be emitted as part of WriteObject().
///
/// The object writer also contains a number of helper methods for writing
/// binary data to the output stream.
class MCObjectWriter {
MCObjectWriter(const MCObjectWriter &); // DO NOT IMPLEMENT
void operator=(const MCObjectWriter &); // DO NOT IMPLEMENT
protected:
raw_ostream &OS;
unsigned IsLittleEndian : 1;
protected: // Can only create subclasses.
MCObjectWriter(raw_ostream &_OS, bool _IsLittleEndian)
: OS(_OS), IsLittleEndian(_IsLittleEndian) {}
public:
virtual ~MCObjectWriter();
bool isLittleEndian() const { return IsLittleEndian; }
raw_ostream &getStream() { return OS; }
/// @name High-Level API
/// @{
/// Perform any late binding of symbols (for example, to assign symbol indices
/// for use when generating relocations).
///
/// This routine is called by the assembler after layout and relaxation is
/// complete.
virtual void ExecutePostLayoutBinding(MCAssembler &Asm) = 0;
/// Record a relocation entry.
///
/// This routine is called by the assembler after layout and relaxation, and
/// post layout binding. The implementation is responsible for storing
/// information about the relocation so that it can be emitted during
/// WriteObject().
virtual void RecordRelocation(const MCAssembler &Asm,
const MCAsmLayout &Layout,
const MCFragment *Fragment,
const MCFixup &Fixup, MCValue Target,
uint64_t &FixedValue) = 0;
/// Check if a fixup is fully resolved.
///
/// This routine is used by the assembler to let the file format decide
/// if a fixup is not fully resolved. For example, one that crosses
/// two sections on ELF.
virtual bool IsFixupFullyResolved(const MCAssembler &Asm,
const MCValue Target,
bool IsPCRel,
const MCFragment *DF) const = 0;
/// Write the object file.
///
/// This routine is called by the assembler after layout and relaxation is
/// complete, fixups have been evaluated and applied, and relocations
/// generated.
virtual void WriteObject(MCAssembler &Asm,
const MCAsmLayout &Layout) = 0;
/// @}
/// @name Binary Output
/// @{
void Write8(uint8_t Value) {
OS << char(Value);
}
void WriteLE16(uint16_t Value) {
Write8(uint8_t(Value >> 0));
Write8(uint8_t(Value >> 8));
}
void WriteLE32(uint32_t Value) {
WriteLE16(uint16_t(Value >> 0));
WriteLE16(uint16_t(Value >> 16));
}
void WriteLE64(uint64_t Value) {
WriteLE32(uint32_t(Value >> 0));
WriteLE32(uint32_t(Value >> 32));
}
void WriteBE16(uint16_t Value) {
Write8(uint8_t(Value >> 8));
Write8(uint8_t(Value >> 0));
}
void WriteBE32(uint32_t Value) {
WriteBE16(uint16_t(Value >> 16));
WriteBE16(uint16_t(Value >> 0));
}
void WriteBE64(uint64_t Value) {
WriteBE32(uint32_t(Value >> 32));
WriteBE32(uint32_t(Value >> 0));
}
void Write16(uint16_t Value) {
if (IsLittleEndian)
WriteLE16(Value);
else
WriteBE16(Value);
}
void Write32(uint32_t Value) {
if (IsLittleEndian)
WriteLE32(Value);
else
WriteBE32(Value);
}
void Write64(uint64_t Value) {
if (IsLittleEndian)
WriteLE64(Value);
else
WriteBE64(Value);
}
void WriteZeros(unsigned N) {
const char Zeros[16] = { 0 };
for (unsigned i = 0, e = N / 16; i != e; ++i)
OS << StringRef(Zeros, 16);
OS << StringRef(Zeros, N % 16);
}
void WriteBytes(StringRef Str, unsigned ZeroFillSize = 0) {
assert((ZeroFillSize == 0 || Str.size () <= ZeroFillSize) &&
"data size greater than fill size, unexpected large write will occur");
OS << Str;
if (ZeroFillSize)
WriteZeros(ZeroFillSize - Str.size());
}
/// @}
/// Utility function to encode a SLEB128 value.
static void EncodeSLEB128(int64_t Value, raw_ostream &OS);
/// Utility function to encode a ULEB128 value.
static void EncodeULEB128(uint64_t Value, raw_ostream &OS);
};
MCObjectWriter *createMachObjectWriter(raw_ostream &OS, bool is64Bit,
uint32_t CPUType, uint32_t CPUSubtype,
bool IsLittleEndian);
MCObjectWriter *createELFObjectWriter(raw_ostream &OS, bool is64Bit,
Triple::OSType OSType, uint16_t EMachine,
bool IsLittleEndian,
bool HasRelocationAddend);
MCObjectWriter *createWinCOFFObjectWriter(raw_ostream &OS, bool is64Bit);
} // End llvm namespace
#endif
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