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https://github.com/c64scene-ar/llvm-6502.git
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251040bc18
No change in functionality. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@171822 91177308-0d34-0410-b5e6-96231b3b80d8
172 lines
5.0 KiB
C++
172 lines
5.0 KiB
C++
//===-- MBlazeAsmBackend.cpp - MBlaze Assembler Backend -------------------===//
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//
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// The LLVM Compiler Infrastructure
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//
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// This file is distributed under the University of Illinois Open Source
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// License. See LICENSE.TXT for details.
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//
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//===----------------------------------------------------------------------===//
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#include "MCTargetDesc/MBlazeMCTargetDesc.h"
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#include "llvm/ADT/Twine.h"
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#include "llvm/MC/MCAsmBackend.h"
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#include "llvm/MC/MCAsmLayout.h"
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#include "llvm/MC/MCAssembler.h"
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#include "llvm/MC/MCELFObjectWriter.h"
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#include "llvm/MC/MCELFSymbolFlags.h"
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#include "llvm/MC/MCExpr.h"
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#include "llvm/MC/MCObjectWriter.h"
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#include "llvm/MC/MCSectionELF.h"
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#include "llvm/MC/MCSectionMachO.h"
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#include "llvm/MC/MCValue.h"
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#include "llvm/Support/ELF.h"
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#include "llvm/Support/ErrorHandling.h"
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#include "llvm/Support/TargetRegistry.h"
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#include "llvm/Support/raw_ostream.h"
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using namespace llvm;
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static unsigned getFixupKindSize(unsigned Kind) {
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switch (Kind) {
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default: llvm_unreachable("invalid fixup kind!");
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case FK_Data_1: return 1;
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case FK_PCRel_2:
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case FK_Data_2: return 2;
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case FK_PCRel_4:
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case FK_Data_4: return 4;
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case FK_Data_8: return 8;
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}
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}
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namespace {
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class MBlazeAsmBackend : public MCAsmBackend {
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public:
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MBlazeAsmBackend(const Target &T)
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: MCAsmBackend() {
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}
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unsigned getNumFixupKinds() const {
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return 2;
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}
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bool mayNeedRelaxation(const MCInst &Inst) const;
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bool fixupNeedsRelaxation(const MCFixup &Fixup,
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uint64_t Value,
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const MCRelaxableFragment *DF,
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const MCAsmLayout &Layout) const;
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void relaxInstruction(const MCInst &Inst, MCInst &Res) const;
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bool writeNopData(uint64_t Count, MCObjectWriter *OW) const;
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unsigned getPointerSize() const {
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return 4;
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}
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};
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static unsigned getRelaxedOpcode(unsigned Op) {
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switch (Op) {
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default: return Op;
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case MBlaze::ADDIK: return MBlaze::ADDIK32;
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case MBlaze::ORI: return MBlaze::ORI32;
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case MBlaze::BRLID: return MBlaze::BRLID32;
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}
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}
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bool MBlazeAsmBackend::mayNeedRelaxation(const MCInst &Inst) const {
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if (getRelaxedOpcode(Inst.getOpcode()) == Inst.getOpcode())
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return false;
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bool hasExprOrImm = false;
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for (unsigned i = 0; i < Inst.getNumOperands(); ++i)
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hasExprOrImm |= Inst.getOperand(i).isExpr();
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return hasExprOrImm;
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}
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bool MBlazeAsmBackend::fixupNeedsRelaxation(const MCFixup &Fixup,
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uint64_t Value,
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const MCRelaxableFragment *DF,
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const MCAsmLayout &Layout) const {
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// FIXME: Is this right? It's what the "generic" code was doing before,
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// but is X86 specific. Is it actually true for MBlaze also, or was it
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// just close enough to not be a big deal?
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//
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// Relax if the value is too big for a (signed) i8.
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return int64_t(Value) != int64_t(int8_t(Value));
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}
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void MBlazeAsmBackend::relaxInstruction(const MCInst &Inst, MCInst &Res) const {
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Res = Inst;
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Res.setOpcode(getRelaxedOpcode(Inst.getOpcode()));
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}
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bool MBlazeAsmBackend::writeNopData(uint64_t Count, MCObjectWriter *OW) const {
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if ((Count % 4) != 0)
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return false;
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for (uint64_t i = 0; i < Count; i += 4)
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OW->Write32(0x00000000);
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return true;
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}
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} // end anonymous namespace
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namespace {
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class ELFMBlazeAsmBackend : public MBlazeAsmBackend {
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public:
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uint8_t OSABI;
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ELFMBlazeAsmBackend(const Target &T, uint8_t _OSABI)
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: MBlazeAsmBackend(T), OSABI(_OSABI) { }
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void applyFixup(const MCFixup &Fixup, char *Data, unsigned DataSize,
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uint64_t Value) const;
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MCObjectWriter *createObjectWriter(raw_ostream &OS) const {
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return createMBlazeELFObjectWriter(OS, OSABI);
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}
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};
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void ELFMBlazeAsmBackend::applyFixup(const MCFixup &Fixup, char *Data,
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unsigned DataSize, uint64_t Value) const {
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unsigned Size = getFixupKindSize(Fixup.getKind());
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assert(Fixup.getOffset() + Size <= DataSize &&
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"Invalid fixup offset!");
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char *data = Data + Fixup.getOffset();
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switch (Size) {
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default: llvm_unreachable("Cannot fixup unknown value.");
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case 1: llvm_unreachable("Cannot fixup 1 byte value.");
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case 8: llvm_unreachable("Cannot fixup 8 byte value.");
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case 4:
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*(data+7) = uint8_t(Value);
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*(data+6) = uint8_t(Value >> 8);
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*(data+3) = uint8_t(Value >> 16);
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*(data+2) = uint8_t(Value >> 24);
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break;
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case 2:
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*(data+3) = uint8_t(Value >> 0);
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*(data+2) = uint8_t(Value >> 8);
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}
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}
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} // end anonymous namespace
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MCAsmBackend *llvm::createMBlazeAsmBackend(const Target &T, StringRef TT,
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StringRef CPU) {
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Triple TheTriple(TT);
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if (TheTriple.isOSDarwin())
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assert(0 && "Mac not supported on MBlaze");
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if (TheTriple.isOSWindows())
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assert(0 && "Windows not supported on MBlaze");
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uint8_t OSABI = MCELFObjectTargetWriter::getOSABI(TheTriple.getOS());
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return new ELFMBlazeAsmBackend(T, OSABI);
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}
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