d3589edafc
`Data` now references the first byte of the fixup offset within the current fragment. MCAssembler::layout asserts that the fixup offset is within either the fixed-size content or the optional variable-size tail, as this is the most the generic code can validate without knowing the target-specific fixup size. Many backends applyFixup assert ``` assert(Offset + Size <= F.getSize() && "Invalid fixup offset!"); ``` This refactoring allows a subsequent change to move the fixed-size content outside of MCSection::ContentStorage, fixing the -fsanitize=pointer-overflow issue of #150846 Pull Request: https://github.com/llvm/llvm-project/pull/151724
277 lines
8.1 KiB
C++
277 lines
8.1 KiB
C++
//===-- SparcAsmBackend.cpp - Sparc Assembler Backend ---------------------===//
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//
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// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
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// See https://llvm.org/LICENSE.txt for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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//
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//===----------------------------------------------------------------------===//
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#include "MCTargetDesc/SparcFixupKinds.h"
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#include "MCTargetDesc/SparcMCTargetDesc.h"
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#include "llvm/ADT/StringSwitch.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/MCExpr.h"
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#include "llvm/MC/MCObjectWriter.h"
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#include "llvm/MC/MCSubtargetInfo.h"
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#include "llvm/MC/MCValue.h"
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#include "llvm/MC/TargetRegistry.h"
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#include "llvm/Support/EndianStream.h"
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using namespace llvm;
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static unsigned adjustFixupValue(unsigned Kind, uint64_t Value) {
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switch (Kind) {
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default:
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assert(uint16_t(Kind) < FirstTargetFixupKind && "Unknown fixup kind!");
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return Value;
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case FK_Data_1:
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case FK_Data_2:
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case FK_Data_4:
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case FK_Data_8:
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return Value;
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case Sparc::fixup_sparc_call30:
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return (Value >> 2) & 0x3fffffff;
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case ELF::R_SPARC_WDISP22:
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return (Value >> 2) & 0x3fffff;
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case ELF::R_SPARC_WDISP19:
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return (Value >> 2) & 0x7ffff;
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case ELF::R_SPARC_WDISP16: {
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// A.3 Branch on Integer Register with Prediction (BPr)
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// Inst{21-20} = d16hi;
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// Inst{13-0} = d16lo;
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unsigned d16hi = (Value >> 16) & 0x3;
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unsigned d16lo = (Value >> 2) & 0x3fff;
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return (d16hi << 20) | d16lo;
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}
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case ELF::R_SPARC_WDISP10: {
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// FIXME this really should be an error reporting check.
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assert((Value & 0x3) == 0);
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// 7.17 Compare and Branch
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// Inst{20-19} = d10hi;
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// Inst{12-5} = d10lo;
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unsigned d10hi = (Value >> 10) & 0x3;
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unsigned d10lo = (Value >> 2) & 0xff;
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return (d10hi << 19) | (d10lo << 5);
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}
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case ELF::R_SPARC_HIX22:
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return (~Value >> 10) & 0x3fffff;
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case ELF::R_SPARC_PC22:
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case ELF::R_SPARC_HI22:
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case ELF::R_SPARC_LM22:
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return (Value >> 10) & 0x3fffff;
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case Sparc::fixup_sparc_13:
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return Value & 0x1fff;
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case ELF::R_SPARC_5:
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return Value & 0x1f;
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case ELF::R_SPARC_LOX10:
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return (Value & 0x3ff) | 0x1c00;
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case ELF::R_SPARC_PC10:
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case ELF::R_SPARC_LO10:
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return Value & 0x3ff;
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case ELF::R_SPARC_H44:
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return (Value >> 22) & 0x3fffff;
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case ELF::R_SPARC_M44:
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return (Value >> 12) & 0x3ff;
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case ELF::R_SPARC_L44:
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return Value & 0xfff;
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case ELF::R_SPARC_HH22:
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return (Value >> 42) & 0x3fffff;
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case ELF::R_SPARC_HM10:
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return (Value >> 32) & 0x3ff;
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}
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}
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/// getFixupKindNumBytes - The number of bytes the fixup may change.
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static unsigned getFixupKindNumBytes(unsigned Kind) {
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switch (Kind) {
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default:
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return 4;
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case FK_Data_1:
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return 1;
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case FK_Data_2:
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return 2;
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case FK_Data_8:
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return 8;
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}
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}
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namespace {
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class SparcAsmBackend : public MCAsmBackend {
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protected:
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bool Is64Bit;
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bool IsV8Plus;
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public:
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SparcAsmBackend(const MCSubtargetInfo &STI)
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: MCAsmBackend(STI.getTargetTriple().isLittleEndian()
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? llvm::endianness::little
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: llvm::endianness::big),
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Is64Bit(STI.getTargetTriple().isArch64Bit()),
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IsV8Plus(STI.hasFeature(Sparc::FeatureV8Plus)) {}
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std::optional<MCFixupKind> getFixupKind(StringRef Name) const override;
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MCFixupKindInfo getFixupKindInfo(MCFixupKind Kind) const override;
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void applyFixup(const MCFragment &, const MCFixup &, const MCValue &Target,
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uint8_t *Data, uint64_t Value, bool IsResolved) override;
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bool writeNopData(raw_ostream &OS, uint64_t Count,
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const MCSubtargetInfo *STI) const override {
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// If the count is not 4-byte aligned, we must be writing data into the
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// text section (otherwise we have unaligned instructions, and thus have
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// far bigger problems), so just write zeros instead.
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OS.write_zeros(Count % 4);
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uint64_t NumNops = Count / 4;
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for (uint64_t i = 0; i != NumNops; ++i)
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support::endian::write<uint32_t>(OS, 0x01000000, Endian);
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return true;
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}
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};
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class ELFSparcAsmBackend : public SparcAsmBackend {
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Triple::OSType OSType;
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public:
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ELFSparcAsmBackend(const MCSubtargetInfo &STI, Triple::OSType OSType)
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: SparcAsmBackend(STI), OSType(OSType) {}
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std::unique_ptr<MCObjectTargetWriter>
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createObjectTargetWriter() const override {
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uint8_t OSABI = MCELFObjectTargetWriter::getOSABI(OSType);
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return createSparcELFObjectWriter(Is64Bit, IsV8Plus, OSABI);
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}
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};
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} // end anonymous namespace
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std::optional<MCFixupKind> SparcAsmBackend::getFixupKind(StringRef Name) const {
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unsigned Type;
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Type = llvm::StringSwitch<unsigned>(Name)
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#define ELF_RELOC(X, Y) .Case(#X, Y)
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#include "llvm/BinaryFormat/ELFRelocs/Sparc.def"
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#undef ELF_RELOC
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.Case("BFD_RELOC_NONE", ELF::R_SPARC_NONE)
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.Case("BFD_RELOC_8", ELF::R_SPARC_8)
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.Case("BFD_RELOC_16", ELF::R_SPARC_16)
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.Case("BFD_RELOC_32", ELF::R_SPARC_32)
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.Case("BFD_RELOC_64", ELF::R_SPARC_64)
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.Default(-1u);
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if (Type == -1u)
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return std::nullopt;
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return static_cast<MCFixupKind>(FirstLiteralRelocationKind + Type);
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}
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MCFixupKindInfo SparcAsmBackend::getFixupKindInfo(MCFixupKind Kind) const {
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// clang-format off
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const static MCFixupKindInfo InfosBE[Sparc::NumTargetFixupKinds] = {
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// name offset bits flags
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{"fixup_sparc_call30", 2, 30, 0},
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{"fixup_sparc_13", 19, 13, 0},
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};
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const static MCFixupKindInfo InfosLE[Sparc::NumTargetFixupKinds] = {
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// name offset bits flags
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{"fixup_sparc_call30", 0, 30, 0},
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{"fixup_sparc_13", 0, 13, 0},
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};
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// clang-format on
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if (!mc::isRelocation(Kind)) {
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if (Kind < FirstTargetFixupKind)
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return MCAsmBackend::getFixupKindInfo(Kind);
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assert(unsigned(Kind - FirstTargetFixupKind) < Sparc::NumTargetFixupKinds &&
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"Invalid kind!");
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if (Endian == llvm::endianness::little)
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return InfosLE[Kind - FirstTargetFixupKind];
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return InfosBE[Kind - FirstTargetFixupKind];
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}
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MCFixupKindInfo Info{};
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switch (uint16_t(Kind)) {
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case ELF::R_SPARC_PC10:
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Info = {"", 22, 10, 0};
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break;
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case ELF::R_SPARC_PC22:
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Info = {"", 10, 22, 0};
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break;
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case ELF::R_SPARC_WDISP10:
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Info = {"", 0, 32, 0};
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break;
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case ELF::R_SPARC_WDISP16:
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Info = {"", 0, 32, 0};
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break;
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case ELF::R_SPARC_WDISP19:
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Info = {"", 13, 19, 0};
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break;
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case ELF::R_SPARC_WDISP22:
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Info = {"", 10, 22, 0};
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break;
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case ELF::R_SPARC_HI22:
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Info = {"", 10, 22, 0};
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break;
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case ELF::R_SPARC_LO10:
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Info = {"", 22, 10, 0};
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break;
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case ELF::R_SPARC_HH22:
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Info = {"", 10, 22, 0};
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break;
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case ELF::R_SPARC_HM10:
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Info = {"", 22, 10, 0};
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break;
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case ELF::R_SPARC_LM22:
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Info = {"", 10, 22, 0};
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break;
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case ELF::R_SPARC_HIX22:
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Info = {"", 10, 22, 0};
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break;
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case ELF::R_SPARC_LOX10:
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Info = {"", 19, 13, 0};
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break;
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}
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if (Endian == llvm::endianness::little)
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Info.TargetOffset = 32 - Info.TargetOffset - Info.TargetSize;
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return Info;
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}
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void SparcAsmBackend::applyFixup(const MCFragment &F, const MCFixup &Fixup,
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const MCValue &Target, uint8_t *Data,
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uint64_t Value, bool IsResolved) {
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maybeAddReloc(F, Fixup, Target, Value, IsResolved);
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if (!IsResolved)
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return;
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Value = adjustFixupValue(Fixup.getKind(), Value);
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unsigned NumBytes = getFixupKindNumBytes(Fixup.getKind());
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// For each byte of the fragment that the fixup touches, mask in the
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// bits from the fixup value.
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for (unsigned i = 0; i != NumBytes; ++i) {
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unsigned Idx = Endian == llvm::endianness::little ? i : (NumBytes - 1) - i;
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Data[Idx] |= uint8_t((Value >> (i * 8)) & 0xff);
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}
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}
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MCAsmBackend *llvm::createSparcAsmBackend(const Target &T,
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const MCSubtargetInfo &STI,
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const MCRegisterInfo &MRI,
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const MCTargetOptions &Options) {
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return new ELFSparcAsmBackend(STI, STI.getTargetTriple().getOS());
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}
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