| //===-- LoongArchAsmBackend.cpp - LoongArch Assembler Backend -*- C++ -*---===// |
| // |
| // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. |
| // See https://llvm.org/LICENSE.txt for license information. |
| // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception |
| // |
| //===----------------------------------------------------------------------===// |
| // |
| // This file implements the LoongArchAsmBackend class. |
| // |
| //===----------------------------------------------------------------------===// |
| |
| #include "LoongArchAsmBackend.h" |
| #include "LoongArchFixupKinds.h" |
| #include "llvm/MC/MCAsmLayout.h" |
| #include "llvm/MC/MCAssembler.h" |
| #include "llvm/MC/MCContext.h" |
| #include "llvm/MC/MCELFObjectWriter.h" |
| #include "llvm/MC/MCValue.h" |
| #include "llvm/Support/Endian.h" |
| #include "llvm/Support/EndianStream.h" |
| |
| #define DEBUG_TYPE "loongarch-asmbackend" |
| |
| using namespace llvm; |
| |
| std::optional<MCFixupKind> |
| LoongArchAsmBackend::getFixupKind(StringRef Name) const { |
| if (STI.getTargetTriple().isOSBinFormatELF()) { |
| auto Type = llvm::StringSwitch<unsigned>(Name) |
| #define ELF_RELOC(X, Y) .Case(#X, Y) |
| #include "llvm/BinaryFormat/ELFRelocs/LoongArch.def" |
| #undef ELF_RELOC |
| .Case("BFD_RELOC_NONE", ELF::R_LARCH_NONE) |
| .Case("BFD_RELOC_32", ELF::R_LARCH_32) |
| .Case("BFD_RELOC_64", ELF::R_LARCH_64) |
| .Default(-1u); |
| if (Type != -1u) |
| return static_cast<MCFixupKind>(FirstLiteralRelocationKind + Type); |
| } |
| return std::nullopt; |
| } |
| |
| const MCFixupKindInfo & |
| LoongArchAsmBackend::getFixupKindInfo(MCFixupKind Kind) const { |
| const static MCFixupKindInfo Infos[] = { |
| // This table *must* be in the order that the fixup_* kinds are defined in |
| // LoongArchFixupKinds.h. |
| // |
| // {name, offset, bits, flags} |
| {"fixup_loongarch_b16", 10, 16, MCFixupKindInfo::FKF_IsPCRel}, |
| {"fixup_loongarch_b21", 0, 26, MCFixupKindInfo::FKF_IsPCRel}, |
| {"fixup_loongarch_b26", 0, 26, MCFixupKindInfo::FKF_IsPCRel}, |
| {"fixup_loongarch_abs_hi20", 5, 20, 0}, |
| {"fixup_loongarch_abs_lo12", 10, 12, 0}, |
| {"fixup_loongarch_abs64_lo20", 5, 20, 0}, |
| {"fixup_loongarch_abs64_hi12", 10, 12, 0}, |
| {"fixup_loongarch_tls_le_hi20", 5, 20, 0}, |
| {"fixup_loongarch_tls_le_lo12", 10, 12, 0}, |
| {"fixup_loongarch_tls_le64_lo20", 5, 20, 0}, |
| {"fixup_loongarch_tls_le64_hi12", 10, 12, 0}, |
| // TODO: Add more fixup kinds. |
| }; |
| |
| static_assert((std::size(Infos)) == LoongArch::NumTargetFixupKinds, |
| "Not all fixup kinds added to Infos array"); |
| |
| // Fixup kinds from .reloc directive are like R_LARCH_NONE. They |
| // do not require any extra processing. |
| if (Kind >= FirstLiteralRelocationKind) |
| return MCAsmBackend::getFixupKindInfo(FK_NONE); |
| |
| if (Kind < FirstTargetFixupKind) |
| return MCAsmBackend::getFixupKindInfo(Kind); |
| |
| assert(unsigned(Kind - FirstTargetFixupKind) < getNumFixupKinds() && |
| "Invalid kind!"); |
| return Infos[Kind - FirstTargetFixupKind]; |
| } |
| |
| static void reportOutOfRangeError(MCContext &Ctx, SMLoc Loc, unsigned N) { |
| Ctx.reportError(Loc, "fixup value out of range [" + Twine(llvm::minIntN(N)) + |
| ", " + Twine(llvm::maxIntN(N)) + "]"); |
| } |
| |
| static uint64_t adjustFixupValue(const MCFixup &Fixup, uint64_t Value, |
| MCContext &Ctx) { |
| switch (Fixup.getTargetKind()) { |
| default: |
| llvm_unreachable("Unknown fixup kind"); |
| case FK_Data_1: |
| case FK_Data_2: |
| case FK_Data_4: |
| case FK_Data_8: |
| return Value; |
| case LoongArch::fixup_loongarch_b16: { |
| if (!isInt<18>(Value)) |
| reportOutOfRangeError(Ctx, Fixup.getLoc(), 18); |
| if (Value % 4) |
| Ctx.reportError(Fixup.getLoc(), "fixup value must be 4-byte aligned"); |
| return (Value >> 2) & 0xffff; |
| } |
| case LoongArch::fixup_loongarch_b21: { |
| if (!isInt<23>(Value)) |
| reportOutOfRangeError(Ctx, Fixup.getLoc(), 23); |
| if (Value % 4) |
| Ctx.reportError(Fixup.getLoc(), "fixup value must be 4-byte aligned"); |
| return ((Value & 0x3fffc) << 8) | ((Value >> 18) & 0x1f); |
| } |
| case LoongArch::fixup_loongarch_b26: { |
| if (!isInt<28>(Value)) |
| reportOutOfRangeError(Ctx, Fixup.getLoc(), 28); |
| if (Value % 4) |
| Ctx.reportError(Fixup.getLoc(), "fixup value must be 4-byte aligned"); |
| return ((Value & 0x3fffc) << 8) | ((Value >> 18) & 0x3ff); |
| } |
| case LoongArch::fixup_loongarch_abs_hi20: |
| case LoongArch::fixup_loongarch_tls_le_hi20: |
| return (Value >> 12) & 0xfffff; |
| case LoongArch::fixup_loongarch_abs_lo12: |
| case LoongArch::fixup_loongarch_tls_le_lo12: |
| return Value & 0xfff; |
| case LoongArch::fixup_loongarch_abs64_lo20: |
| case LoongArch::fixup_loongarch_tls_le64_lo20: |
| return (Value >> 32) & 0xfffff; |
| case LoongArch::fixup_loongarch_abs64_hi12: |
| case LoongArch::fixup_loongarch_tls_le64_hi12: |
| return (Value >> 52) & 0xfff; |
| } |
| } |
| |
| void LoongArchAsmBackend::applyFixup(const MCAssembler &Asm, |
| const MCFixup &Fixup, |
| const MCValue &Target, |
| MutableArrayRef<char> Data, uint64_t Value, |
| bool IsResolved, |
| const MCSubtargetInfo *STI) const { |
| if (!Value) |
| return; // Doesn't change encoding. |
| |
| MCFixupKind Kind = Fixup.getKind(); |
| if (Kind >= FirstLiteralRelocationKind) |
| return; |
| MCFixupKindInfo Info = getFixupKindInfo(Kind); |
| MCContext &Ctx = Asm.getContext(); |
| |
| // Apply any target-specific value adjustments. |
| Value = adjustFixupValue(Fixup, Value, Ctx); |
| |
| // Shift the value into position. |
| Value <<= Info.TargetOffset; |
| |
| unsigned Offset = Fixup.getOffset(); |
| unsigned NumBytes = alignTo(Info.TargetSize + Info.TargetOffset, 8) / 8; |
| |
| assert(Offset + NumBytes <= Data.size() && "Invalid fixup offset!"); |
| // For each byte of the fragment that the fixup touches, mask in the |
| // bits from the fixup value. |
| for (unsigned I = 0; I != NumBytes; ++I) { |
| Data[Offset + I] |= uint8_t((Value >> (I * 8)) & 0xff); |
| } |
| } |
| |
| bool LoongArchAsmBackend::shouldForceRelocation(const MCAssembler &Asm, |
| const MCFixup &Fixup, |
| const MCValue &Target) { |
| if (Fixup.getKind() >= FirstLiteralRelocationKind) |
| return true; |
| switch (Fixup.getTargetKind()) { |
| default: |
| return false; |
| case FK_Data_1: |
| case FK_Data_2: |
| case FK_Data_4: |
| case FK_Data_8: |
| return !Target.isAbsolute(); |
| } |
| } |
| |
| bool LoongArchAsmBackend::writeNopData(raw_ostream &OS, uint64_t Count, |
| const MCSubtargetInfo *STI) const { |
| // We mostly follow binutils' convention here: align to 4-byte boundary with a |
| // 0-fill padding. |
| OS.write_zeros(Count % 4); |
| |
| // The remainder is now padded with 4-byte nops. |
| // nop: andi r0, r0, 0 |
| for (; Count >= 4; Count -= 4) |
| OS.write("\0\0\x40\x03", 4); |
| |
| return true; |
| } |
| |
| std::unique_ptr<MCObjectTargetWriter> |
| LoongArchAsmBackend::createObjectTargetWriter() const { |
| return createLoongArchELFObjectWriter(OSABI, Is64Bit); |
| } |
| |
| MCAsmBackend *llvm::createLoongArchAsmBackend(const Target &T, |
| const MCSubtargetInfo &STI, |
| const MCRegisterInfo &MRI, |
| const MCTargetOptions &Options) { |
| const Triple &TT = STI.getTargetTriple(); |
| uint8_t OSABI = MCELFObjectTargetWriter::getOSABI(TT.getOS()); |
| return new LoongArchAsmBackend(STI, OSABI, TT.isArch64Bit()); |
| } |