llvm-project/llvm/lib/Object/ELFObjectFile.cpp

627 lines
18 KiB
C++

//===- ELFObjectFile.cpp - ELF object file implementation -----------------===//
//
// 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
//
//===----------------------------------------------------------------------===//
//
// Part of the ELFObjectFile class implementation.
//
//===----------------------------------------------------------------------===//
#include "llvm/Object/ELFObjectFile.h"
#include "llvm/ADT/Triple.h"
#include "llvm/BinaryFormat/ELF.h"
#include "llvm/MC/MCInstrAnalysis.h"
#include "llvm/MC/SubtargetFeature.h"
#include "llvm/Object/ELF.h"
#include "llvm/Object/ELFTypes.h"
#include "llvm/Object/Error.h"
#include "llvm/Support/ARMAttributeParser.h"
#include "llvm/Support/ARMBuildAttributes.h"
#include "llvm/Support/Endian.h"
#include "llvm/Support/ErrorHandling.h"
#include "llvm/Support/MathExtras.h"
#include "llvm/Support/RISCVAttributeParser.h"
#include "llvm/Support/RISCVAttributes.h"
#include "llvm/Support/TargetRegistry.h"
#include <algorithm>
#include <cstddef>
#include <cstdint>
#include <memory>
#include <string>
#include <system_error>
#include <utility>
using namespace llvm;
using namespace object;
const EnumEntry<unsigned> llvm::object::ElfSymbolTypes[NumElfSymbolTypes] = {
{"None", "NOTYPE", ELF::STT_NOTYPE},
{"Object", "OBJECT", ELF::STT_OBJECT},
{"Function", "FUNC", ELF::STT_FUNC},
{"Section", "SECTION", ELF::STT_SECTION},
{"File", "FILE", ELF::STT_FILE},
{"Common", "COMMON", ELF::STT_COMMON},
{"TLS", "TLS", ELF::STT_TLS},
{"Unknown", "<unknown>: 7", 7},
{"Unknown", "<unknown>: 8", 8},
{"Unknown", "<unknown>: 9", 9},
{"GNU_IFunc", "IFUNC", ELF::STT_GNU_IFUNC},
{"OS Specific", "<OS specific>: 11", 11},
{"OS Specific", "<OS specific>: 12", 12},
{"Proc Specific", "<processor specific>: 13", 13},
{"Proc Specific", "<processor specific>: 14", 14},
{"Proc Specific", "<processor specific>: 15", 15}
};
ELFObjectFileBase::ELFObjectFileBase(unsigned int Type, MemoryBufferRef Source)
: ObjectFile(Type, Source) {}
template <class ELFT>
static Expected<std::unique_ptr<ELFObjectFile<ELFT>>>
createPtr(MemoryBufferRef Object) {
auto Ret = ELFObjectFile<ELFT>::create(Object);
if (Error E = Ret.takeError())
return std::move(E);
return std::make_unique<ELFObjectFile<ELFT>>(std::move(*Ret));
}
Expected<std::unique_ptr<ObjectFile>>
ObjectFile::createELFObjectFile(MemoryBufferRef Obj) {
std::pair<unsigned char, unsigned char> Ident =
getElfArchType(Obj.getBuffer());
std::size_t MaxAlignment =
1ULL << countTrailingZeros(uintptr_t(Obj.getBufferStart()));
if (MaxAlignment < 2)
return createError("Insufficient alignment");
if (Ident.first == ELF::ELFCLASS32) {
if (Ident.second == ELF::ELFDATA2LSB)
return createPtr<ELF32LE>(Obj);
else if (Ident.second == ELF::ELFDATA2MSB)
return createPtr<ELF32BE>(Obj);
else
return createError("Invalid ELF data");
} else if (Ident.first == ELF::ELFCLASS64) {
if (Ident.second == ELF::ELFDATA2LSB)
return createPtr<ELF64LE>(Obj);
else if (Ident.second == ELF::ELFDATA2MSB)
return createPtr<ELF64BE>(Obj);
else
return createError("Invalid ELF data");
}
return createError("Invalid ELF class");
}
SubtargetFeatures ELFObjectFileBase::getMIPSFeatures() const {
SubtargetFeatures Features;
unsigned PlatformFlags = getPlatformFlags();
switch (PlatformFlags & ELF::EF_MIPS_ARCH) {
case ELF::EF_MIPS_ARCH_1:
break;
case ELF::EF_MIPS_ARCH_2:
Features.AddFeature("mips2");
break;
case ELF::EF_MIPS_ARCH_3:
Features.AddFeature("mips3");
break;
case ELF::EF_MIPS_ARCH_4:
Features.AddFeature("mips4");
break;
case ELF::EF_MIPS_ARCH_5:
Features.AddFeature("mips5");
break;
case ELF::EF_MIPS_ARCH_32:
Features.AddFeature("mips32");
break;
case ELF::EF_MIPS_ARCH_64:
Features.AddFeature("mips64");
break;
case ELF::EF_MIPS_ARCH_32R2:
Features.AddFeature("mips32r2");
break;
case ELF::EF_MIPS_ARCH_64R2:
Features.AddFeature("mips64r2");
break;
case ELF::EF_MIPS_ARCH_32R6:
Features.AddFeature("mips32r6");
break;
case ELF::EF_MIPS_ARCH_64R6:
Features.AddFeature("mips64r6");
break;
default:
llvm_unreachable("Unknown EF_MIPS_ARCH value");
}
switch (PlatformFlags & ELF::EF_MIPS_MACH) {
case ELF::EF_MIPS_MACH_NONE:
// No feature associated with this value.
break;
case ELF::EF_MIPS_MACH_OCTEON:
Features.AddFeature("cnmips");
break;
default:
llvm_unreachable("Unknown EF_MIPS_ARCH value");
}
if (PlatformFlags & ELF::EF_MIPS_ARCH_ASE_M16)
Features.AddFeature("mips16");
if (PlatformFlags & ELF::EF_MIPS_MICROMIPS)
Features.AddFeature("micromips");
return Features;
}
SubtargetFeatures ELFObjectFileBase::getARMFeatures() const {
SubtargetFeatures Features;
ARMAttributeParser Attributes;
if (Error E = getBuildAttributes(Attributes)) {
consumeError(std::move(E));
return SubtargetFeatures();
}
// both ARMv7-M and R have to support thumb hardware div
bool isV7 = false;
Optional<unsigned> Attr =
Attributes.getAttributeValue(ARMBuildAttrs::CPU_arch);
if (Attr.hasValue())
isV7 = Attr.getValue() == ARMBuildAttrs::v7;
Attr = Attributes.getAttributeValue(ARMBuildAttrs::CPU_arch_profile);
if (Attr.hasValue()) {
switch (Attr.getValue()) {
case ARMBuildAttrs::ApplicationProfile:
Features.AddFeature("aclass");
break;
case ARMBuildAttrs::RealTimeProfile:
Features.AddFeature("rclass");
if (isV7)
Features.AddFeature("hwdiv");
break;
case ARMBuildAttrs::MicroControllerProfile:
Features.AddFeature("mclass");
if (isV7)
Features.AddFeature("hwdiv");
break;
}
}
Attr = Attributes.getAttributeValue(ARMBuildAttrs::THUMB_ISA_use);
if (Attr.hasValue()) {
switch (Attr.getValue()) {
default:
break;
case ARMBuildAttrs::Not_Allowed:
Features.AddFeature("thumb", false);
Features.AddFeature("thumb2", false);
break;
case ARMBuildAttrs::AllowThumb32:
Features.AddFeature("thumb2");
break;
}
}
Attr = Attributes.getAttributeValue(ARMBuildAttrs::FP_arch);
if (Attr.hasValue()) {
switch (Attr.getValue()) {
default:
break;
case ARMBuildAttrs::Not_Allowed:
Features.AddFeature("vfp2sp", false);
Features.AddFeature("vfp3d16sp", false);
Features.AddFeature("vfp4d16sp", false);
break;
case ARMBuildAttrs::AllowFPv2:
Features.AddFeature("vfp2");
break;
case ARMBuildAttrs::AllowFPv3A:
case ARMBuildAttrs::AllowFPv3B:
Features.AddFeature("vfp3");
break;
case ARMBuildAttrs::AllowFPv4A:
case ARMBuildAttrs::AllowFPv4B:
Features.AddFeature("vfp4");
break;
}
}
Attr = Attributes.getAttributeValue(ARMBuildAttrs::Advanced_SIMD_arch);
if (Attr.hasValue()) {
switch (Attr.getValue()) {
default:
break;
case ARMBuildAttrs::Not_Allowed:
Features.AddFeature("neon", false);
Features.AddFeature("fp16", false);
break;
case ARMBuildAttrs::AllowNeon:
Features.AddFeature("neon");
break;
case ARMBuildAttrs::AllowNeon2:
Features.AddFeature("neon");
Features.AddFeature("fp16");
break;
}
}
Attr = Attributes.getAttributeValue(ARMBuildAttrs::MVE_arch);
if (Attr.hasValue()) {
switch (Attr.getValue()) {
default:
break;
case ARMBuildAttrs::Not_Allowed:
Features.AddFeature("mve", false);
Features.AddFeature("mve.fp", false);
break;
case ARMBuildAttrs::AllowMVEInteger:
Features.AddFeature("mve.fp", false);
Features.AddFeature("mve");
break;
case ARMBuildAttrs::AllowMVEIntegerAndFloat:
Features.AddFeature("mve.fp");
break;
}
}
Attr = Attributes.getAttributeValue(ARMBuildAttrs::DIV_use);
if (Attr.hasValue()) {
switch (Attr.getValue()) {
default:
break;
case ARMBuildAttrs::DisallowDIV:
Features.AddFeature("hwdiv", false);
Features.AddFeature("hwdiv-arm", false);
break;
case ARMBuildAttrs::AllowDIVExt:
Features.AddFeature("hwdiv");
Features.AddFeature("hwdiv-arm");
break;
}
}
return Features;
}
SubtargetFeatures ELFObjectFileBase::getRISCVFeatures() const {
SubtargetFeatures Features;
unsigned PlatformFlags = getPlatformFlags();
if (PlatformFlags & ELF::EF_RISCV_RVC) {
Features.AddFeature("c");
}
// Add features according to the ELF attribute section.
// If there are any unrecognized features, ignore them.
RISCVAttributeParser Attributes;
if (Error E = getBuildAttributes(Attributes)) {
// TODO Propagate Error.
consumeError(std::move(E));
return Features; // Keep "c" feature if there is one in PlatformFlags.
}
Optional<StringRef> Attr = Attributes.getAttributeString(RISCVAttrs::ARCH);
if (Attr.hasValue()) {
// The Arch pattern is [rv32|rv64][i|e]version(_[m|a|f|d|c]version)*
// Version string pattern is (major)p(minor). Major and minor are optional.
// For example, a version number could be 2p0, 2, or p92.
StringRef Arch = Attr.getValue();
if (Arch.consume_front("rv32"))
Features.AddFeature("64bit", false);
else if (Arch.consume_front("rv64"))
Features.AddFeature("64bit");
while (!Arch.empty()) {
switch (Arch[0]) {
default:
break; // Ignore unexpected features.
case 'i':
Features.AddFeature("e", false);
break;
case 'd':
Features.AddFeature("f"); // D-ext will imply F-ext.
LLVM_FALLTHROUGH;
case 'e':
case 'm':
case 'a':
case 'f':
case 'c':
Features.AddFeature(Arch.take_front());
break;
}
// FIXME: Handle version numbers.
Arch = Arch.drop_until([](char c) { return c == '_' || c == '\0'; });
Arch = Arch.drop_while([](char c) { return c == '_'; });
}
}
return Features;
}
SubtargetFeatures ELFObjectFileBase::getFeatures() const {
switch (getEMachine()) {
case ELF::EM_MIPS:
return getMIPSFeatures();
case ELF::EM_ARM:
return getARMFeatures();
case ELF::EM_RISCV:
return getRISCVFeatures();
default:
return SubtargetFeatures();
}
}
Optional<StringRef> ELFObjectFileBase::tryGetCPUName() const {
switch (getEMachine()) {
case ELF::EM_AMDGPU:
return getAMDGPUCPUName();
default:
return None;
}
}
StringRef ELFObjectFileBase::getAMDGPUCPUName() const {
assert(getEMachine() == ELF::EM_AMDGPU);
unsigned CPU = getPlatformFlags() & ELF::EF_AMDGPU_MACH;
switch (CPU) {
// Radeon HD 2000/3000 Series (R600).
case ELF::EF_AMDGPU_MACH_R600_R600:
return "r600";
case ELF::EF_AMDGPU_MACH_R600_R630:
return "r630";
case ELF::EF_AMDGPU_MACH_R600_RS880:
return "rs880";
case ELF::EF_AMDGPU_MACH_R600_RV670:
return "rv670";
// Radeon HD 4000 Series (R700).
case ELF::EF_AMDGPU_MACH_R600_RV710:
return "rv710";
case ELF::EF_AMDGPU_MACH_R600_RV730:
return "rv730";
case ELF::EF_AMDGPU_MACH_R600_RV770:
return "rv770";
// Radeon HD 5000 Series (Evergreen).
case ELF::EF_AMDGPU_MACH_R600_CEDAR:
return "cedar";
case ELF::EF_AMDGPU_MACH_R600_CYPRESS:
return "cypress";
case ELF::EF_AMDGPU_MACH_R600_JUNIPER:
return "juniper";
case ELF::EF_AMDGPU_MACH_R600_REDWOOD:
return "redwood";
case ELF::EF_AMDGPU_MACH_R600_SUMO:
return "sumo";
// Radeon HD 6000 Series (Northern Islands).
case ELF::EF_AMDGPU_MACH_R600_BARTS:
return "barts";
case ELF::EF_AMDGPU_MACH_R600_CAICOS:
return "caicos";
case ELF::EF_AMDGPU_MACH_R600_CAYMAN:
return "cayman";
case ELF::EF_AMDGPU_MACH_R600_TURKS:
return "turks";
// AMDGCN GFX6.
case ELF::EF_AMDGPU_MACH_AMDGCN_GFX600:
return "gfx600";
case ELF::EF_AMDGPU_MACH_AMDGCN_GFX601:
return "gfx601";
// AMDGCN GFX7.
case ELF::EF_AMDGPU_MACH_AMDGCN_GFX700:
return "gfx700";
case ELF::EF_AMDGPU_MACH_AMDGCN_GFX701:
return "gfx701";
case ELF::EF_AMDGPU_MACH_AMDGCN_GFX702:
return "gfx702";
case ELF::EF_AMDGPU_MACH_AMDGCN_GFX703:
return "gfx703";
case ELF::EF_AMDGPU_MACH_AMDGCN_GFX704:
return "gfx704";
// AMDGCN GFX8.
case ELF::EF_AMDGPU_MACH_AMDGCN_GFX801:
return "gfx801";
case ELF::EF_AMDGPU_MACH_AMDGCN_GFX802:
return "gfx802";
case ELF::EF_AMDGPU_MACH_AMDGCN_GFX803:
return "gfx803";
case ELF::EF_AMDGPU_MACH_AMDGCN_GFX810:
return "gfx810";
// AMDGCN GFX9.
case ELF::EF_AMDGPU_MACH_AMDGCN_GFX900:
return "gfx900";
case ELF::EF_AMDGPU_MACH_AMDGCN_GFX902:
return "gfx902";
case ELF::EF_AMDGPU_MACH_AMDGCN_GFX904:
return "gfx904";
case ELF::EF_AMDGPU_MACH_AMDGCN_GFX906:
return "gfx906";
case ELF::EF_AMDGPU_MACH_AMDGCN_GFX908:
return "gfx908";
case ELF::EF_AMDGPU_MACH_AMDGCN_GFX909:
return "gfx909";
// AMDGCN GFX10.
case ELF::EF_AMDGPU_MACH_AMDGCN_GFX1010:
return "gfx1010";
case ELF::EF_AMDGPU_MACH_AMDGCN_GFX1011:
return "gfx1011";
case ELF::EF_AMDGPU_MACH_AMDGCN_GFX1012:
return "gfx1012";
case ELF::EF_AMDGPU_MACH_AMDGCN_GFX1030:
return "gfx1030";
default:
llvm_unreachable("Unknown EF_AMDGPU_MACH value");
}
}
// FIXME Encode from a tablegen description or target parser.
void ELFObjectFileBase::setARMSubArch(Triple &TheTriple) const {
if (TheTriple.getSubArch() != Triple::NoSubArch)
return;
ARMAttributeParser Attributes;
if (Error E = getBuildAttributes(Attributes)) {
// TODO Propagate Error.
consumeError(std::move(E));
return;
}
std::string Triple;
// Default to ARM, but use the triple if it's been set.
if (TheTriple.isThumb())
Triple = "thumb";
else
Triple = "arm";
Optional<unsigned> Attr =
Attributes.getAttributeValue(ARMBuildAttrs::CPU_arch);
if (Attr.hasValue()) {
switch (Attr.getValue()) {
case ARMBuildAttrs::v4:
Triple += "v4";
break;
case ARMBuildAttrs::v4T:
Triple += "v4t";
break;
case ARMBuildAttrs::v5T:
Triple += "v5t";
break;
case ARMBuildAttrs::v5TE:
Triple += "v5te";
break;
case ARMBuildAttrs::v5TEJ:
Triple += "v5tej";
break;
case ARMBuildAttrs::v6:
Triple += "v6";
break;
case ARMBuildAttrs::v6KZ:
Triple += "v6kz";
break;
case ARMBuildAttrs::v6T2:
Triple += "v6t2";
break;
case ARMBuildAttrs::v6K:
Triple += "v6k";
break;
case ARMBuildAttrs::v7:
Triple += "v7";
break;
case ARMBuildAttrs::v6_M:
Triple += "v6m";
break;
case ARMBuildAttrs::v6S_M:
Triple += "v6sm";
break;
case ARMBuildAttrs::v7E_M:
Triple += "v7em";
break;
case ARMBuildAttrs::v8_A:
Triple += "v8a";
break;
case ARMBuildAttrs::v8_R:
Triple += "v8r";
break;
case ARMBuildAttrs::v8_M_Base:
Triple += "v8m.base";
break;
case ARMBuildAttrs::v8_M_Main:
Triple += "v8m.main";
break;
case ARMBuildAttrs::v8_1_M_Main:
Triple += "v8.1m.main";
break;
}
}
if (!isLittleEndian())
Triple += "eb";
TheTriple.setArchName(Triple);
}
std::vector<std::pair<Optional<DataRefImpl>, uint64_t>>
ELFObjectFileBase::getPltAddresses() const {
std::string Err;
const auto Triple = makeTriple();
const auto *T = TargetRegistry::lookupTarget(Triple.str(), Err);
if (!T)
return {};
uint64_t JumpSlotReloc = 0;
switch (Triple.getArch()) {
case Triple::x86:
JumpSlotReloc = ELF::R_386_JUMP_SLOT;
break;
case Triple::x86_64:
JumpSlotReloc = ELF::R_X86_64_JUMP_SLOT;
break;
case Triple::aarch64:
JumpSlotReloc = ELF::R_AARCH64_JUMP_SLOT;
break;
default:
return {};
}
std::unique_ptr<const MCInstrInfo> MII(T->createMCInstrInfo());
std::unique_ptr<const MCInstrAnalysis> MIA(
T->createMCInstrAnalysis(MII.get()));
if (!MIA)
return {};
Optional<SectionRef> Plt = None, RelaPlt = None, GotPlt = None;
for (const SectionRef &Section : sections()) {
Expected<StringRef> NameOrErr = Section.getName();
if (!NameOrErr) {
consumeError(NameOrErr.takeError());
continue;
}
StringRef Name = *NameOrErr;
if (Name == ".plt")
Plt = Section;
else if (Name == ".rela.plt" || Name == ".rel.plt")
RelaPlt = Section;
else if (Name == ".got.plt")
GotPlt = Section;
}
if (!Plt || !RelaPlt || !GotPlt)
return {};
Expected<StringRef> PltContents = Plt->getContents();
if (!PltContents) {
consumeError(PltContents.takeError());
return {};
}
auto PltEntries = MIA->findPltEntries(Plt->getAddress(),
arrayRefFromStringRef(*PltContents),
GotPlt->getAddress(), Triple);
// Build a map from GOT entry virtual address to PLT entry virtual address.
DenseMap<uint64_t, uint64_t> GotToPlt;
for (const auto &Entry : PltEntries)
GotToPlt.insert(std::make_pair(Entry.second, Entry.first));
// Find the relocations in the dynamic relocation table that point to
// locations in the GOT for which we know the corresponding PLT entry.
std::vector<std::pair<Optional<DataRefImpl>, uint64_t>> Result;
for (const auto &Relocation : RelaPlt->relocations()) {
if (Relocation.getType() != JumpSlotReloc)
continue;
auto PltEntryIter = GotToPlt.find(Relocation.getOffset());
if (PltEntryIter != GotToPlt.end()) {
symbol_iterator Sym = Relocation.getSymbol();
if (Sym == symbol_end())
Result.emplace_back(None, PltEntryIter->second);
else
Result.emplace_back(Sym->getRawDataRefImpl(), PltEntryIter->second);
}
}
return Result;
}