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//===-- MBlazeAsmBackend.cpp - MBlaze Assembler Backend -------------------===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
#include "MCTargetDesc/MBlazeMCTargetDesc.h"
#include "llvm/MC/MCAsmBackend.h"
#include "llvm/MC/MCAssembler.h"
#include "llvm/MC/MCAsmLayout.h"
#include "llvm/MC/MCELFObjectWriter.h"
#include "llvm/MC/MCELFSymbolFlags.h"
#include "llvm/MC/MCExpr.h"
#include "llvm/MC/MCObjectWriter.h"
#include "llvm/MC/MCSectionELF.h"
#include "llvm/MC/MCSectionMachO.h"
#include "llvm/MC/MCValue.h"
#include "llvm/ADT/Twine.h"
#include "llvm/Support/ELF.h"
#include "llvm/Support/ErrorHandling.h"
#include "llvm/Support/TargetRegistry.h"
#include "llvm/Support/raw_ostream.h"
using namespace llvm;
static unsigned getFixupKindSize(unsigned Kind) {
switch (Kind) {
default: assert(0 && "invalid fixup kind!");
case FK_Data_1: return 1;
case FK_PCRel_2:
case FK_Data_2: return 2;
case FK_PCRel_4:
case FK_Data_4: return 4;
case FK_Data_8: return 8;
}
}
namespace {
class MBlazeELFObjectWriter : public MCELFObjectTargetWriter {
public:
MBlazeELFObjectWriter(Triple::OSType OSType)
: MCELFObjectTargetWriter(/*is64Bit*/ false, OSType, ELF::EM_MBLAZE,
/*HasRelocationAddend*/ true) {}
};
class MBlazeAsmBackend : public MCAsmBackend {
public:
MBlazeAsmBackend(const Target &T)
: MCAsmBackend() {
}
unsigned getNumFixupKinds() const {
return 2;
}
bool MayNeedRelaxation(const MCInst &Inst) const;
void RelaxInstruction(const MCInst &Inst, MCInst &Res) const;
bool WriteNopData(uint64_t Count, MCObjectWriter *OW) const;
unsigned getPointerSize() const {
return 4;
}
};
static unsigned getRelaxedOpcode(unsigned Op) {
switch (Op) {
default: return Op;
case MBlaze::ADDIK: return MBlaze::ADDIK32;
case MBlaze::ORI: return MBlaze::ORI32;
case MBlaze::BRLID: return MBlaze::BRLID32;
}
}
bool MBlazeAsmBackend::MayNeedRelaxation(const MCInst &Inst) const {
if (getRelaxedOpcode(Inst.getOpcode()) == Inst.getOpcode())
return false;
bool hasExprOrImm = false;
for (unsigned i = 0; i < Inst.getNumOperands(); ++i)
hasExprOrImm |= Inst.getOperand(i).isExpr();
return hasExprOrImm;
}
void MBlazeAsmBackend::RelaxInstruction(const MCInst &Inst, MCInst &Res) const {
Res = Inst;
Res.setOpcode(getRelaxedOpcode(Inst.getOpcode()));
}
bool MBlazeAsmBackend::WriteNopData(uint64_t Count, MCObjectWriter *OW) const {
if ((Count % 4) != 0)
return false;
for (uint64_t i = 0; i < Count; i += 4)
OW->Write32(0x00000000);
return true;
}
} // end anonymous namespace
namespace {
class ELFMBlazeAsmBackend : public MBlazeAsmBackend {
public:
Triple::OSType OSType;
ELFMBlazeAsmBackend(const Target &T, Triple::OSType _OSType)
: MBlazeAsmBackend(T), OSType(_OSType) { }
void ApplyFixup(const MCFixup &Fixup, char *Data, unsigned DataSize,
uint64_t Value) const;
MCObjectWriter *createObjectWriter(raw_ostream &OS) const {
return createELFObjectWriter(new MBlazeELFObjectWriter(OSType), OS,
/*IsLittleEndian*/ false);
}
};
void ELFMBlazeAsmBackend::ApplyFixup(const MCFixup &Fixup, char *Data,
unsigned DataSize, uint64_t Value) const {
unsigned Size = getFixupKindSize(Fixup.getKind());
assert(Fixup.getOffset() + Size <= DataSize &&
"Invalid fixup offset!");
char *data = Data + Fixup.getOffset();
switch (Size) {
default: llvm_unreachable("Cannot fixup unknown value.");
case 1: llvm_unreachable("Cannot fixup 1 byte value.");
case 8: llvm_unreachable("Cannot fixup 8 byte value.");
case 4:
*(data+7) = uint8_t(Value);
*(data+6) = uint8_t(Value >> 8);
*(data+3) = uint8_t(Value >> 16);
*(data+2) = uint8_t(Value >> 24);
break;
case 2:
*(data+3) = uint8_t(Value >> 0);
*(data+2) = uint8_t(Value >> 8);
}
}
} // end anonymous namespace
MCAsmBackend *llvm::createMBlazeAsmBackend(const Target &T, StringRef TT) {
Triple TheTriple(TT);
if (TheTriple.isOSDarwin())
assert(0 && "Mac not supported on MBlaze");
if (TheTriple.isOSWindows())
assert(0 && "Windows not supported on MBlaze");
return new ELFMBlazeAsmBackend(T, TheTriple.getOS());
}
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