llvm-6502/lib/Target/PowerPC/MCTargetDesc/PPCAsmBackend.cpp

191 lines
6.0 KiB
C++
Raw Normal View History

//===-- PPCAsmBackend.cpp - PPC 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/PPCMCTargetDesc.h"
#include "MCTargetDesc/PPCFixupKinds.h"
#include "llvm/MC/MCAsmBackend.h"
#include "llvm/MC/MCELFObjectWriter.h"
#include "llvm/MC/MCFixupKindInfo.h"
#include "llvm/MC/MCMachObjectWriter.h"
#include "llvm/MC/MCSectionMachO.h"
#include "llvm/MC/MCObjectWriter.h"
#include "llvm/MC/MCValue.h"
#include "llvm/Object/MachOFormat.h"
#include "llvm/Support/ELF.h"
#include "llvm/Support/ErrorHandling.h"
#include "llvm/Support/TargetRegistry.h"
using namespace llvm;
static unsigned adjustFixupValue(unsigned Kind, uint64_t Value) {
switch (Kind) {
default:
llvm_unreachable("Unknown fixup kind!");
case FK_Data_1:
case FK_Data_2:
case FK_Data_4:
return Value;
case PPC::fixup_ppc_brcond14:
return Value & 0x3ffc;
case PPC::fixup_ppc_br24:
return Value & 0x3fffffc;
#if 0
case PPC::fixup_ppc_hi16:
return (Value >> 16) & 0xffff;
#endif
case PPC::fixup_ppc_ha16:
return ((Value >> 16) + ((Value & 0x8000) ? 1 : 0)) & 0xffff;
case PPC::fixup_ppc_lo16:
return Value & 0xffff;
}
}
namespace {
class PPCMachObjectWriter : public MCMachObjectTargetWriter {
public:
PPCMachObjectWriter(bool Is64Bit, uint32_t CPUType,
uint32_t CPUSubtype)
: MCMachObjectTargetWriter(Is64Bit, CPUType, CPUSubtype) {}
void RecordRelocation(MachObjectWriter *Writer,
const MCAssembler &Asm, const MCAsmLayout &Layout,
const MCFragment *Fragment, const MCFixup &Fixup,
MCValue Target, uint64_t &FixedValue) {}
};
class PPCAsmBackend : public MCAsmBackend {
const Target &TheTarget;
public:
PPCAsmBackend(const Target &T) : MCAsmBackend(), TheTarget(T) {}
unsigned getNumFixupKinds() const { return PPC::NumTargetFixupKinds; }
const MCFixupKindInfo &getFixupKindInfo(MCFixupKind Kind) const {
const static MCFixupKindInfo Infos[PPC::NumTargetFixupKinds] = {
// name offset bits flags
{ "fixup_ppc_br24", 6, 24, MCFixupKindInfo::FKF_IsPCRel },
{ "fixup_ppc_brcond14", 16, 14, MCFixupKindInfo::FKF_IsPCRel },
{ "fixup_ppc_lo16", 16, 16, 0 },
{ "fixup_ppc_ha16", 16, 16, 0 },
{ "fixup_ppc_lo14", 16, 14, 0 }
};
if (Kind < FirstTargetFixupKind)
return MCAsmBackend::getFixupKindInfo(Kind);
assert(unsigned(Kind - FirstTargetFixupKind) < getNumFixupKinds() &&
"Invalid kind!");
return Infos[Kind - FirstTargetFixupKind];
}
bool mayNeedRelaxation(const MCInst &Inst) const {
// FIXME.
return false;
}
bool fixupNeedsRelaxation(const MCFixup &Fixup,
uint64_t Value,
const MCInstFragment *DF,
const MCAsmLayout &Layout) const {
// FIXME.
llvm_unreachable("relaxInstruction() unimplemented");
}
void relaxInstruction(const MCInst &Inst, MCInst &Res) const {
// FIXME.
llvm_unreachable("relaxInstruction() unimplemented");
}
bool writeNopData(uint64_t Count, MCObjectWriter *OW) const {
// FIXME: Zero fill for now. That's not right, but at least will get the
// section size right.
for (uint64_t i = 0; i != Count; ++i)
OW->Write8(0);
return true;
}
unsigned getPointerSize() const {
StringRef Name = TheTarget.getName();
if (Name == "ppc64") return 8;
assert(Name == "ppc32" && "Unknown target name!");
return 4;
}
};
} // end anonymous namespace
// FIXME: This should be in a separate file.
namespace {
class DarwinPPCAsmBackend : public PPCAsmBackend {
public:
DarwinPPCAsmBackend(const Target &T) : PPCAsmBackend(T) { }
void applyFixup(const MCFixup &Fixup, char *Data, unsigned DataSize,
uint64_t Value) const {
llvm_unreachable("UNIMP");
}
MCObjectWriter *createObjectWriter(raw_ostream &OS) const {
bool is64 = getPointerSize() == 8;
return createMachObjectWriter(new PPCMachObjectWriter(
/*Is64Bit=*/is64,
(is64 ? object::mach::CTM_PowerPC64 :
object::mach::CTM_PowerPC),
object::mach::CSPPC_ALL),
OS, /*IsLittleEndian=*/false);
}
virtual bool doesSectionRequireSymbols(const MCSection &Section) const {
return false;
}
};
class ELFPPCAsmBackend : public PPCAsmBackend {
uint8_t OSABI;
public:
ELFPPCAsmBackend(const Target &T, uint8_t OSABI) :
PPCAsmBackend(T), OSABI(OSABI) { }
void applyFixup(const MCFixup &Fixup, char *Data, unsigned DataSize,
uint64_t Value) const {
Value = adjustFixupValue(Fixup.getKind(), Value);
if (!Value) return; // Doesn't change encoding.
unsigned Offset = Fixup.getOffset();
// For each byte of the fragment that the fixup touches, mask in the bits from
// the fixup value. The Value has been "split up" into the appropriate
// bitfields above.
for (unsigned i = 0; i != 4; ++i)
Data[Offset + i] |= uint8_t((Value >> ((4 - i - 1)*8)) & 0xff);
}
MCObjectWriter *createObjectWriter(raw_ostream &OS) const {
bool is64 = getPointerSize() == 8;
return createPPCELFObjectWriter(OS, is64, OSABI);
}
virtual bool doesSectionRequireSymbols(const MCSection &Section) const {
return false;
}
};
} // end anonymous namespace
MCAsmBackend *llvm::createPPCAsmBackend(const Target &T, StringRef TT) {
if (Triple(TT).isOSDarwin())
return new DarwinPPCAsmBackend(T);
uint8_t OSABI = MCELFObjectTargetWriter::getOSABI(Triple(TT).getOS());
return new ELFPPCAsmBackend(T, OSABI);
}