118 lines
4.0 KiB
C++
118 lines
4.0 KiB
C++
//===-- SystemZMCAsmBackend.cpp - SystemZ 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/SystemZMCTargetDesc.h"
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#include "MCTargetDesc/SystemZMCFixups.h"
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#include "llvm/MC/MCAsmBackend.h"
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#include "llvm/MC/MCELFObjectWriter.h"
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#include "llvm/MC/MCFixupKindInfo.h"
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#include "llvm/MC/MCInst.h"
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#include "llvm/MC/MCObjectWriter.h"
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using namespace llvm;
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// Value is a fully-resolved relocation value: Symbol + Addend [- Pivot].
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// Return the bits that should be installed in a relocation field for
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// fixup kind Kind.
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static uint64_t extractBitsForFixup(MCFixupKind Kind, uint64_t Value) {
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if (Kind < FirstTargetFixupKind)
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return Value;
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switch (unsigned(Kind)) {
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case SystemZ::FK_390_PC16DBL:
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case SystemZ::FK_390_PC32DBL:
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return (int64_t)Value / 2;
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case SystemZ::FK_390_TLS_CALL:
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return 0;
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}
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llvm_unreachable("Unknown fixup kind!");
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}
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namespace {
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class SystemZMCAsmBackend : public MCAsmBackend {
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uint8_t OSABI;
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public:
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SystemZMCAsmBackend(uint8_t osABI)
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: OSABI(osABI) {}
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// Override MCAsmBackend
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unsigned getNumFixupKinds() const override {
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return SystemZ::NumTargetFixupKinds;
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}
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const MCFixupKindInfo &getFixupKindInfo(MCFixupKind Kind) const override;
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void applyFixup(const MCFixup &Fixup, char *Data, unsigned DataSize,
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uint64_t Value, bool IsPCRel) const override;
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bool mayNeedRelaxation(const MCInst &Inst) const override {
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return false;
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}
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bool fixupNeedsRelaxation(const MCFixup &Fixup, uint64_t Value,
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const MCRelaxableFragment *Fragment,
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const MCAsmLayout &Layout) const override {
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return false;
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}
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void relaxInstruction(const MCInst &Inst, MCInst &Res) const override {
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llvm_unreachable("SystemZ does do not have assembler relaxation");
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}
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bool writeNopData(uint64_t Count, MCObjectWriter *OW) const override;
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MCObjectWriter *createObjectWriter(raw_pwrite_stream &OS) const override {
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return createSystemZObjectWriter(OS, OSABI);
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}
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};
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} // end anonymous namespace
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const MCFixupKindInfo &
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SystemZMCAsmBackend::getFixupKindInfo(MCFixupKind Kind) const {
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const static MCFixupKindInfo Infos[SystemZ::NumTargetFixupKinds] = {
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{ "FK_390_PC16DBL", 0, 16, MCFixupKindInfo::FKF_IsPCRel },
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{ "FK_390_PC32DBL", 0, 32, MCFixupKindInfo::FKF_IsPCRel },
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{ "FK_390_TLS_CALL", 0, 0, 0 }
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};
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if (Kind < FirstTargetFixupKind)
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return MCAsmBackend::getFixupKindInfo(Kind);
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assert(unsigned(Kind - FirstTargetFixupKind) < getNumFixupKinds() &&
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"Invalid kind!");
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return Infos[Kind - FirstTargetFixupKind];
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}
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void SystemZMCAsmBackend::applyFixup(const MCFixup &Fixup, char *Data,
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unsigned DataSize, uint64_t Value,
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bool IsPCRel) const {
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MCFixupKind Kind = Fixup.getKind();
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unsigned Offset = Fixup.getOffset();
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unsigned Size = (getFixupKindInfo(Kind).TargetSize + 7) / 8;
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assert(Offset + Size <= DataSize && "Invalid fixup offset!");
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// Big-endian insertion of Size bytes.
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Value = extractBitsForFixup(Kind, Value);
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unsigned ShiftValue = (Size * 8) - 8;
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for (unsigned I = 0; I != Size; ++I) {
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Data[Offset + I] |= uint8_t(Value >> ShiftValue);
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ShiftValue -= 8;
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}
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}
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bool SystemZMCAsmBackend::writeNopData(uint64_t Count,
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MCObjectWriter *OW) const {
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for (uint64_t I = 0; I != Count; ++I)
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OW->write8(7);
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return true;
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}
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MCAsmBackend *llvm::createSystemZMCAsmBackend(const Target &T,
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const MCRegisterInfo &MRI,
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const Triple &TT, StringRef CPU) {
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uint8_t OSABI = MCELFObjectTargetWriter::getOSABI(TT.getOS());
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return new SystemZMCAsmBackend(OSABI);
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}
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