forked from OSchip/llvm-project
405 lines
12 KiB
C++
405 lines
12 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/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},
|
|
{"GNU_IFunc", "IFUNC", ELF::STT_GNU_IFUNC}};
|
|
|
|
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 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))
|
|
return SubtargetFeatures();
|
|
|
|
// both ARMv7-M and R have to support thumb hardware div
|
|
bool isV7 = false;
|
|
if (Attributes.hasAttribute(ARMBuildAttrs::CPU_arch))
|
|
isV7 = Attributes.getAttributeValue(ARMBuildAttrs::CPU_arch)
|
|
== ARMBuildAttrs::v7;
|
|
|
|
if (Attributes.hasAttribute(ARMBuildAttrs::CPU_arch_profile)) {
|
|
switch(Attributes.getAttributeValue(ARMBuildAttrs::CPU_arch_profile)) {
|
|
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;
|
|
}
|
|
}
|
|
|
|
if (Attributes.hasAttribute(ARMBuildAttrs::THUMB_ISA_use)) {
|
|
switch(Attributes.getAttributeValue(ARMBuildAttrs::THUMB_ISA_use)) {
|
|
default:
|
|
break;
|
|
case ARMBuildAttrs::Not_Allowed:
|
|
Features.AddFeature("thumb", false);
|
|
Features.AddFeature("thumb2", false);
|
|
break;
|
|
case ARMBuildAttrs::AllowThumb32:
|
|
Features.AddFeature("thumb2");
|
|
break;
|
|
}
|
|
}
|
|
|
|
if (Attributes.hasAttribute(ARMBuildAttrs::FP_arch)) {
|
|
switch(Attributes.getAttributeValue(ARMBuildAttrs::FP_arch)) {
|
|
default:
|
|
break;
|
|
case ARMBuildAttrs::Not_Allowed:
|
|
Features.AddFeature("vfp2d16sp", 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;
|
|
}
|
|
}
|
|
|
|
if (Attributes.hasAttribute(ARMBuildAttrs::Advanced_SIMD_arch)) {
|
|
switch(Attributes.getAttributeValue(ARMBuildAttrs::Advanced_SIMD_arch)) {
|
|
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;
|
|
}
|
|
}
|
|
|
|
if (Attributes.hasAttribute(ARMBuildAttrs::DIV_use)) {
|
|
switch(Attributes.getAttributeValue(ARMBuildAttrs::DIV_use)) {
|
|
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");
|
|
}
|
|
|
|
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();
|
|
}
|
|
}
|
|
|
|
// 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))
|
|
return;
|
|
|
|
std::string Triple;
|
|
// Default to ARM, but use the triple if it's been set.
|
|
if (TheTriple.isThumb())
|
|
Triple = "thumb";
|
|
else
|
|
Triple = "arm";
|
|
|
|
if (Attributes.hasAttribute(ARMBuildAttrs::CPU_arch)) {
|
|
switch(Attributes.getAttributeValue(ARMBuildAttrs::CPU_arch)) {
|
|
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;
|
|
}
|
|
}
|
|
if (!isLittleEndian())
|
|
Triple += "eb";
|
|
|
|
TheTriple.setArchName(Triple);
|
|
}
|
|
|
|
std::vector<std::pair<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()) {
|
|
StringRef Name;
|
|
if (Section.getName(Name))
|
|
continue;
|
|
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<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())
|
|
Result.push_back(std::make_pair(
|
|
Relocation.getSymbol()->getRawDataRefImpl(), PltEntryIter->second));
|
|
}
|
|
return Result;
|
|
}
|