Google Git Google Git
Sign in
llvm/llvm-project/lldb/ce744eab9182653deab76c71cb8f16a1ea96e801/./source/Plugins/ObjectFile/ELF/ObjectFileELF.cpp
blob: 662f69c8e6df8c348f7541f637c206c4e7401909 [file]
//===-- ObjectFileELF.cpp -------------------------------------------------===//
//
// 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
//
//===----------------------------------------------------------------------===//
#include "ObjectFileELF.h"
#include <algorithm>
#include <cassert>
#include <optional>
#include <unordered_map>
#include "lldb/Core/Debugger.h"
#include "lldb/Core/Module.h"
#include "lldb/Core/ModuleSpec.h"
#include "lldb/Core/PluginManager.h"
#include "lldb/Core/Progress.h"
#include "lldb/Core/Section.h"
#include "lldb/Host/FileSystem.h"
#include "lldb/Symbol/DWARFCallFrameInfo.h"
#include "lldb/Symbol/SymbolContext.h"
#include "lldb/Target/Process.h"
#include "lldb/Target/SectionLoadList.h"
#include "lldb/Target/Target.h"
#include "lldb/Utility/ArchSpec.h"
#include "lldb/Utility/DataBufferHeap.h"
#include "lldb/Utility/DataExtractor.h"
#include "lldb/Utility/FileSpecList.h"
#include "lldb/Utility/LLDBLog.h"
#include "lldb/Utility/Log.h"
#include "lldb/Utility/RangeMap.h"
#include "lldb/Utility/Status.h"
#include "lldb/Utility/Stream.h"
#include "lldb/Utility/StreamString.h"
#include "lldb/Utility/Timer.h"
#include "llvm/ADT/IntervalMap.h"
#include "llvm/ADT/PointerUnion.h"
#include "llvm/ADT/StringRef.h"
#include "llvm/BinaryFormat/ELF.h"
#include "llvm/Object/Decompressor.h"
#include "llvm/Support/ARMBuildAttributes.h"
#include "llvm/Support/CRC.h"
#include "llvm/Support/Compression.h"
#include "llvm/Support/FormatVariadic.h"
#include "llvm/Support/MathExtras.h"
#include "llvm/Support/MemoryBuffer.h"
#include "llvm/Support/MipsABIFlags.h"
#include "llvm/Support/RISCVAttributes.h"
#include "llvm/TargetParser/RISCVISAInfo.h"
#include "llvm/TargetParser/SubtargetFeature.h"
#define CASE_AND_STREAM(s, def, width) \
case def: \
s->Printf("%-*s", width, #def); \
break;
using namespace lldb;
using namespace lldb_private;
using namespace elf;
using namespace llvm::ELF;
LLDB_PLUGIN_DEFINE(ObjectFileELF)
// ELF note owner definitions
static const char *const LLDB_NT_OWNER_FREEBSD = "FreeBSD";
static const char *const LLDB_NT_OWNER_GNU = "GNU";
static const char *const LLDB_NT_OWNER_NETBSD = "NetBSD";
static const char *const LLDB_NT_OWNER_NETBSDCORE = "NetBSD-CORE";
static const char *const LLDB_NT_OWNER_OPENBSD = "OpenBSD";
static const char *const LLDB_NT_OWNER_ANDROID = "Android";
static const char *const LLDB_NT_OWNER_CORE = "CORE";
static const char *const LLDB_NT_OWNER_LINUX = "LINUX";
// ELF note type definitions
static const elf_word LLDB_NT_FREEBSD_ABI_TAG = 0x01;
static const elf_word LLDB_NT_FREEBSD_ABI_SIZE = 4;
static const elf_word LLDB_NT_GNU_ABI_TAG = 0x01;
static const elf_word LLDB_NT_GNU_ABI_SIZE = 16;
static const elf_word LLDB_NT_GNU_BUILD_ID_TAG = 0x03;
static const elf_word LLDB_NT_NETBSD_IDENT_TAG = 1;
static const elf_word LLDB_NT_NETBSD_IDENT_DESCSZ = 4;
static const elf_word LLDB_NT_NETBSD_IDENT_NAMESZ = 7;
static const elf_word LLDB_NT_NETBSD_PROCINFO = 1;
// GNU ABI note OS constants
static const elf_word LLDB_NT_GNU_ABI_OS_LINUX = 0x00;
static const elf_word LLDB_NT_GNU_ABI_OS_HURD = 0x01;
static const elf_word LLDB_NT_GNU_ABI_OS_SOLARIS = 0x02;
namespace {
//===----------------------------------------------------------------------===//
/// \class ELFRelocation
/// Generic wrapper for ELFRel and ELFRela.
///
/// This helper class allows us to parse both ELFRel and ELFRela relocation
/// entries in a generic manner.
class ELFRelocation {
public:
/// Constructs an ELFRelocation entry with a personality as given by @p
/// type.
///
/// \param type Either DT_REL or DT_RELA. Any other value is invalid.
ELFRelocation(unsigned type);
~ELFRelocation();
bool Parse(const lldb_private::DataExtractor &data, lldb::offset_t *offset);
static unsigned RelocType32(const ELFRelocation &rel);
static unsigned RelocType64(const ELFRelocation &rel);
static unsigned RelocSymbol32(const ELFRelocation &rel);
static unsigned RelocSymbol64(const ELFRelocation &rel);
static elf_addr RelocOffset32(const ELFRelocation &rel);
static elf_addr RelocOffset64(const ELFRelocation &rel);
static elf_sxword RelocAddend32(const ELFRelocation &rel);
static elf_sxword RelocAddend64(const ELFRelocation &rel);
bool IsRela() { return (llvm::isa<ELFRela *>(reloc)); }
private:
typedef llvm::PointerUnion<ELFRel *, ELFRela *> RelocUnion;
RelocUnion reloc;
};
lldb::SectionSP MergeSections(lldb::SectionSP lhs, lldb::SectionSP rhs) {
assert(lhs && rhs);
lldb::ModuleSP lhs_module_parent = lhs->GetModule();
lldb::ModuleSP rhs_module_parent = rhs->GetModule();
assert(lhs_module_parent && rhs_module_parent);
// Do a sanity check, these should be the same.
if (lhs->GetFileAddress() != rhs->GetFileAddress())
lhs_module_parent->ReportWarning(
"mismatch addresses for section {0} when "
"merging with {1}, expected: {2:x}, "
"actual: {3:x}",
lhs->GetTypeAsCString(), rhs_module_parent->GetFileSpec().GetPath(),
lhs->GetFileAddress(), rhs->GetFileAddress());
// We want to take the greater of two sections. If LHS and RHS are both
// SHT_NOBITS, we should default to LHS. If RHS has a bigger section,
// indicating it has data that wasn't stripped, we should take that instead.
return rhs->GetFileSize() > lhs->GetFileSize() ? rhs : lhs;
}
} // end anonymous namespace
ELFRelocation::ELFRelocation(unsigned type) {
if (type == DT_REL || type == SHT_REL)
reloc = new ELFRel();
else if (type == DT_RELA || type == SHT_RELA)
reloc = new ELFRela();
else {
assert(false && "unexpected relocation type");
reloc = static_cast<ELFRel *>(nullptr);
}
}
ELFRelocation::~ELFRelocation() {
if (auto *elfrel = llvm::dyn_cast<ELFRel *>(reloc))
delete elfrel;
else
delete llvm::cast<ELFRela *>(reloc);
}
bool ELFRelocation::Parse(const lldb_private::DataExtractor &data,
lldb::offset_t *offset) {
if (auto *elfrel = llvm::dyn_cast<ELFRel *>(reloc))
return elfrel->Parse(data, offset);
else
return llvm::cast<ELFRela *>(reloc)->Parse(data, offset);
}
unsigned ELFRelocation::RelocType32(const ELFRelocation &rel) {
if (auto *elfrel = llvm::dyn_cast<ELFRel *>(rel.reloc))
return ELFRel::RelocType32(*elfrel);
else
return ELFRela::RelocType32(*llvm::cast<ELFRela *>(rel.reloc));
}
unsigned ELFRelocation::RelocType64(const ELFRelocation &rel) {
if (auto *elfrel = llvm::dyn_cast<ELFRel *>(rel.reloc))
return ELFRel::RelocType64(*elfrel);
else
return ELFRela::RelocType64(*llvm::cast<ELFRela *>(rel.reloc));
}
unsigned ELFRelocation::RelocSymbol32(const ELFRelocation &rel) {
if (auto *elfrel = llvm::dyn_cast<ELFRel *>(rel.reloc))
return ELFRel::RelocSymbol32(*elfrel);
else
return ELFRela::RelocSymbol32(*llvm::cast<ELFRela *>(rel.reloc));
}
unsigned ELFRelocation::RelocSymbol64(const ELFRelocation &rel) {
if (auto *elfrel = llvm::dyn_cast<ELFRel *>(rel.reloc))
return ELFRel::RelocSymbol64(*elfrel);
else
return ELFRela::RelocSymbol64(*llvm::cast<ELFRela *>(rel.reloc));
}
elf_addr ELFRelocation::RelocOffset32(const ELFRelocation &rel) {
if (auto *elfrel = llvm::dyn_cast<ELFRel *>(rel.reloc))
return elfrel->r_offset;
else
return llvm::cast<ELFRela *>(rel.reloc)->r_offset;
}
elf_addr ELFRelocation::RelocOffset64(const ELFRelocation &rel) {
if (auto *elfrel = llvm::dyn_cast<ELFRel *>(rel.reloc))
return elfrel->r_offset;
else
return llvm::cast<ELFRela *>(rel.reloc)->r_offset;
}
elf_sxword ELFRelocation::RelocAddend32(const ELFRelocation &rel) {
if (llvm::isa<ELFRel *>(rel.reloc))
return 0;
else
return llvm::cast<ELFRela *>(rel.reloc)->r_addend;
}
elf_sxword ELFRelocation::RelocAddend64(const ELFRelocation &rel) {
if (llvm::isa<ELFRel *>(rel.reloc))
return 0;
else
return llvm::cast<ELFRela *>(rel.reloc)->r_addend;
}
static user_id_t SegmentID(size_t PHdrIndex) {
return ~user_id_t(PHdrIndex);
}
bool ELFNote::Parse(const DataExtractor &data, lldb::offset_t *offset) {
// Read all fields.
if (data.GetU32(offset, &n_namesz, 3) == nullptr)
return false;
// The name field is required to be null-terminated, and n_namesz includes the
// terminating nul in observed implementations (contrary to the ELF-64 spec).
// A special case is needed for cores generated by some older Linux versions,
// which write a note named "CORE" without a null terminator and n_namesz = 4.
if (n_namesz == 4) {
char buf[4];
if (data.ExtractBytes(*offset, 4, data.GetByteOrder(), buf) != 4)
return false;
if (strncmp(buf, "CORE", 4) == 0) {
n_name = "CORE";
*offset += 4;
return true;
}
}
const char *cstr = data.GetCStr(offset, llvm::alignTo(n_namesz, 4));
if (cstr == nullptr) {
Log *log = GetLog(LLDBLog::Symbols);
LLDB_LOGF(log, "Failed to parse note name lacking null terminator");
return false;
}
n_name = cstr;
return true;
}
static uint32_t mipsVariantFromElfFlags (const elf::ELFHeader &header) {
const uint32_t mips_arch = header.e_flags & llvm::ELF::EF_MIPS_ARCH;
uint32_t endian = header.e_ident[EI_DATA];
uint32_t arch_variant = ArchSpec::eMIPSSubType_unknown;
uint32_t fileclass = header.e_ident[EI_CLASS];
// If there aren't any elf flags available (e.g core elf file) then return
// default
// 32 or 64 bit arch (without any architecture revision) based on object file's class.
if (header.e_type == ET_CORE) {
switch (fileclass) {
case llvm::ELF::ELFCLASS32:
return (endian == ELFDATA2LSB) ? ArchSpec::eMIPSSubType_mips32el
: ArchSpec::eMIPSSubType_mips32;
case llvm::ELF::ELFCLASS64:
return (endian == ELFDATA2LSB) ? ArchSpec::eMIPSSubType_mips64el
: ArchSpec::eMIPSSubType_mips64;
default:
return arch_variant;
}
}
switch (mips_arch) {
case llvm::ELF::EF_MIPS_ARCH_1:
case llvm::ELF::EF_MIPS_ARCH_2:
case llvm::ELF::EF_MIPS_ARCH_32:
return (endian == ELFDATA2LSB) ? ArchSpec::eMIPSSubType_mips32el
: ArchSpec::eMIPSSubType_mips32;
case llvm::ELF::EF_MIPS_ARCH_32R2:
return (endian == ELFDATA2LSB) ? ArchSpec::eMIPSSubType_mips32r2el
: ArchSpec::eMIPSSubType_mips32r2;
case llvm::ELF::EF_MIPS_ARCH_32R6:
return (endian == ELFDATA2LSB) ? ArchSpec::eMIPSSubType_mips32r6el
: ArchSpec::eMIPSSubType_mips32r6;
case llvm::ELF::EF_MIPS_ARCH_3:
case llvm::ELF::EF_MIPS_ARCH_4:
case llvm::ELF::EF_MIPS_ARCH_5:
case llvm::ELF::EF_MIPS_ARCH_64:
return (endian == ELFDATA2LSB) ? ArchSpec::eMIPSSubType_mips64el
: ArchSpec::eMIPSSubType_mips64;
case llvm::ELF::EF_MIPS_ARCH_64R2:
return (endian == ELFDATA2LSB) ? ArchSpec::eMIPSSubType_mips64r2el
: ArchSpec::eMIPSSubType_mips64r2;
case llvm::ELF::EF_MIPS_ARCH_64R6:
return (endian == ELFDATA2LSB) ? ArchSpec::eMIPSSubType_mips64r6el
: ArchSpec::eMIPSSubType_mips64r6;
default:
break;
}
return arch_variant;
}
static uint32_t riscvVariantFromElfFlags(const elf::ELFHeader &header) {
uint32_t fileclass = header.e_ident[EI_CLASS];
switch (fileclass) {
case llvm::ELF::ELFCLASS32:
return ArchSpec::eRISCVSubType_riscv32;
case llvm::ELF::ELFCLASS64:
return ArchSpec::eRISCVSubType_riscv64;
default:
return ArchSpec::eRISCVSubType_unknown;
}
}
static uint32_t ppc64VariantFromElfFlags(const elf::ELFHeader &header) {
uint32_t endian = header.e_ident[EI_DATA];
if (endian == ELFDATA2LSB)
return ArchSpec::eCore_ppc64le_generic;
else
return ArchSpec::eCore_ppc64_generic;
}
static uint32_t loongarchVariantFromElfFlags(const elf::ELFHeader &header) {
uint32_t fileclass = header.e_ident[EI_CLASS];
switch (fileclass) {
case llvm::ELF::ELFCLASS32:
return ArchSpec::eLoongArchSubType_loongarch32;
case llvm::ELF::ELFCLASS64:
return ArchSpec::eLoongArchSubType_loongarch64;
default:
return ArchSpec::eLoongArchSubType_unknown;
}
}
static uint32_t AMDGPUVariantFromElfFlags(const elf::ELFHeader &header) {
// Only HSA objects encode the exact GPU model, as an EF_AMDGPU_MACH value.
if (header.e_ident[EI_OSABI] == ELFOSABI_AMDGPU_HSA) {
switch (header.e_ident[EI_ABIVERSION]) {
// HSA V2 does not encode a CPU model.
case ELFABIVERSION_AMDGPU_HSA_V2:
break;
case ELFABIVERSION_AMDGPU_HSA_V3:
case ELFABIVERSION_AMDGPU_HSA_V4:
case ELFABIVERSION_AMDGPU_HSA_V5:
case ELFABIVERSION_AMDGPU_HSA_V6:
// The CPU model is the EF_AMDGPU_MACH value in the bottom byte of
// e_flags.
return header.e_flags & EF_AMDGPU_MACH;
}
}
return LLDB_INVALID_CPUTYPE;
}
static uint32_t subTypeFromElfHeader(const elf::ELFHeader &header) {
if (header.e_machine == llvm::ELF::EM_MIPS)
return mipsVariantFromElfFlags(header);
else if (header.e_machine == llvm::ELF::EM_PPC64)
return ppc64VariantFromElfFlags(header);
else if (header.e_machine == llvm::ELF::EM_RISCV)
return riscvVariantFromElfFlags(header);
else if (header.e_machine == llvm::ELF::EM_LOONGARCH)
return loongarchVariantFromElfFlags(header);
else if (header.e_machine == llvm::ELF::EM_AMDGPU)
return AMDGPUVariantFromElfFlags(header);
return LLDB_INVALID_CPUTYPE;
}
char ObjectFileELF::ID;
// Arbitrary constant used as UUID prefix for core files.
const uint32_t ObjectFileELF::g_core_uuid_magic(0xE210C);
// Static methods.
void ObjectFileELF::Initialize() {
PluginManager::RegisterPlugin(GetPluginNameStatic(),
GetPluginDescriptionStatic(), CreateInstance,
CreateMemoryInstance, GetModuleSpecifications);
}
void ObjectFileELF::Terminate() {
PluginManager::UnregisterPlugin(CreateInstance);
}
ObjectFile *ObjectFileELF::CreateInstance(const lldb::ModuleSP &module_sp,
DataExtractorSP extractor_sp,
lldb::offset_t data_offset,
const lldb_private::FileSpec *file,
lldb::offset_t file_offset,
lldb::offset_t length) {
bool mapped_writable = false;
if (!extractor_sp || !extractor_sp->HasData()) {
DataBufferSP buffer_sp = MapFileDataWritable(*file, length, file_offset);
if (!buffer_sp)
return nullptr;
extractor_sp = std::make_shared<DataExtractor>(buffer_sp);
data_offset = 0;
mapped_writable = true;
}
assert(extractor_sp && extractor_sp->HasData());
DataBufferSP data_sp = extractor_sp->GetSharedDataBuffer();
if (data_sp->GetByteSize() <= (llvm::ELF::EI_NIDENT + data_offset))
return nullptr;
const uint8_t *magic = data_sp->GetBytes() + data_offset;
if (!ELFHeader::MagicBytesMatch(magic))
return nullptr;
// Update the data to contain the entire file if it doesn't already
if (data_sp->GetByteSize() < length) {
data_sp = MapFileDataWritable(*file, length, file_offset);
if (!data_sp)
return nullptr;
data_offset = 0;
mapped_writable = true;
magic = data_sp->GetBytes();
extractor_sp->SetData(data_sp);
}
// If we didn't map the data as writable take ownership of the buffer.
if (!mapped_writable) {
data_sp = std::make_shared<DataBufferHeap>(data_sp->GetBytes(),
data_sp->GetByteSize());
data_offset = 0;
magic = data_sp->GetBytes();
extractor_sp->SetData(data_sp);
}
unsigned address_size = ELFHeader::AddressSizeInBytes(magic);
if (address_size == 4 || address_size == 8) {
extractor_sp->SetAddressByteSize(address_size);
std::unique_ptr<ObjectFileELF> objfile_up(new ObjectFileELF(
module_sp, extractor_sp, data_offset, file, file_offset, length));
ArchSpec spec = objfile_up->GetArchitecture();
if (spec && objfile_up->SetModulesArchitecture(spec))
return objfile_up.release();
}
return nullptr;
}
ObjectFile *ObjectFileELF::CreateMemoryInstance(
const lldb::ModuleSP &module_sp, WritableDataBufferSP data_sp,
const lldb::ProcessSP &process_sp, lldb::addr_t header_addr) {
if (!data_sp || data_sp->GetByteSize() < (llvm::ELF::EI_NIDENT))
return nullptr;
const uint8_t *magic = data_sp->GetBytes();
if (!ELFHeader::MagicBytesMatch(magic))
return nullptr;
// Read the ELF header first so we can figure out how many bytes we need
// to read to get as least the ELF header + program headers.
DataExtractor data;
data.SetData(data_sp);
elf::ELFHeader hdr;
lldb::offset_t offset = 0;
if (!hdr.Parse(data, &offset))
return nullptr;
// Make sure the address size is set correctly in the ELF header.
if (!hdr.Is32Bit() && !hdr.Is64Bit())
return nullptr;
// Figure out where the program headers end and read enough bytes to get the
// program headers in their entirety.
lldb::offset_t end_phdrs = hdr.e_phoff + (hdr.e_phentsize * hdr.e_phnum);
if (end_phdrs > data_sp->GetByteSize())
data_sp = ReadMemory(process_sp, header_addr, end_phdrs);
std::unique_ptr<ObjectFileELF> objfile_up(
new ObjectFileELF(module_sp, data_sp, process_sp, header_addr));
ArchSpec spec = objfile_up->GetArchitecture();
if (spec && objfile_up->SetModulesArchitecture(spec))
return objfile_up.release();
return nullptr;
}
bool ObjectFileELF::MagicBytesMatch(DataBufferSP data_sp,
lldb::addr_t data_offset,
lldb::addr_t data_length) {
if (data_sp &&
data_sp->GetByteSize() > (llvm::ELF::EI_NIDENT + data_offset)) {
const uint8_t *magic = data_sp->GetBytes() + data_offset;
return ELFHeader::MagicBytesMatch(magic);
}
return false;
}
static uint32_t calc_crc32(uint32_t init, const DataExtractor &data) {
return llvm::crc32(init,
llvm::ArrayRef(data.GetDataStart(), data.GetByteSize()));
}
uint32_t ObjectFileELF::CalculateELFNotesSegmentsCRC32(
const ProgramHeaderColl &program_headers, DataExtractor &object_data) {
uint32_t core_notes_crc = 0;
for (const ELFProgramHeader &H : program_headers) {
if (H.p_type == llvm::ELF::PT_NOTE) {
const elf_off ph_offset = H.p_offset;
const size_t ph_size = H.p_filesz;
DataExtractor segment_data;
if (segment_data.SetData(object_data, ph_offset, ph_size) != ph_size) {
// The ELF program header contained incorrect data, probably corefile
// is incomplete or corrupted.
break;
}
core_notes_crc = calc_crc32(core_notes_crc, segment_data);
}
}
return core_notes_crc;
}
static const char *OSABIAsCString(unsigned char osabi_byte) {
#define _MAKE_OSABI_CASE(x) \
case x: \
return #x
switch (osabi_byte) {
_MAKE_OSABI_CASE(ELFOSABI_NONE);
_MAKE_OSABI_CASE(ELFOSABI_HPUX);
_MAKE_OSABI_CASE(ELFOSABI_NETBSD);
_MAKE_OSABI_CASE(ELFOSABI_GNU);
_MAKE_OSABI_CASE(ELFOSABI_HURD);
_MAKE_OSABI_CASE(ELFOSABI_SOLARIS);
_MAKE_OSABI_CASE(ELFOSABI_AIX);
_MAKE_OSABI_CASE(ELFOSABI_IRIX);
_MAKE_OSABI_CASE(ELFOSABI_FREEBSD);
_MAKE_OSABI_CASE(ELFOSABI_TRU64);
_MAKE_OSABI_CASE(ELFOSABI_MODESTO);
_MAKE_OSABI_CASE(ELFOSABI_OPENBSD);
_MAKE_OSABI_CASE(ELFOSABI_OPENVMS);
_MAKE_OSABI_CASE(ELFOSABI_NSK);
_MAKE_OSABI_CASE(ELFOSABI_AROS);
_MAKE_OSABI_CASE(ELFOSABI_FENIXOS);
_MAKE_OSABI_CASE(ELFOSABI_C6000_ELFABI);
_MAKE_OSABI_CASE(ELFOSABI_C6000_LINUX);
_MAKE_OSABI_CASE(ELFOSABI_ARM);
_MAKE_OSABI_CASE(ELFOSABI_STANDALONE);
default:
return "<unknown-osabi>";
}
#undef _MAKE_OSABI_CASE
}
//
// WARNING : This function is being deprecated
// It's functionality has moved to ArchSpec::SetArchitecture This function is
// only being kept to validate the move.
//
// TODO : Remove this function
static bool GetOsFromOSABI(unsigned char osabi_byte,
llvm::Triple::OSType &ostype) {
switch (osabi_byte) {
case ELFOSABI_AIX:
ostype = llvm::Triple::OSType::AIX;
break;
case ELFOSABI_FREEBSD:
ostype = llvm::Triple::OSType::FreeBSD;
break;
case ELFOSABI_GNU:
ostype = llvm::Triple::OSType::Linux;
break;
case ELFOSABI_NETBSD:
ostype = llvm::Triple::OSType::NetBSD;
break;
case ELFOSABI_OPENBSD:
ostype = llvm::Triple::OSType::OpenBSD;
break;
case ELFOSABI_SOLARIS:
ostype = llvm::Triple::OSType::Solaris;
break;
case ELFOSABI_AMDGPU_HSA:
ostype = llvm::Triple::OSType::AMDHSA;
break;
default:
ostype = llvm::Triple::OSType::UnknownOS;
}
return ostype != llvm::Triple::OSType::UnknownOS;
}
ModuleSpecList ObjectFileELF::GetModuleSpecifications(
const lldb_private::FileSpec &file, lldb::DataExtractorSP &extractor_sp,
lldb::offset_t file_offset, lldb::offset_t length) {
Log *log = GetLog(LLDBLog::Modules);
if (!extractor_sp || !extractor_sp->HasData())
return {};
if (ObjectFileELF::MagicBytesMatch(extractor_sp->GetSharedDataBuffer(), 0,
extractor_sp->GetByteSize())) {
elf::ELFHeader header;
lldb::offset_t header_offset = 0;
if (header.Parse(*extractor_sp, &header_offset)) {
ModuleSpec spec(file);
// In Android API level 23 and above, bionic dynamic linker is able to
// load .so file directly from zip file. In that case, .so file is
// page aligned and uncompressed, and this module spec should retain the
// .so file offset and file size to pass through the information from
// lldb-server to LLDB. For normal file, file_offset should be 0,
// length should be the size of the file.
spec.SetObjectOffset(file_offset);
spec.SetObjectSize(length);
const uint32_t sub_type = subTypeFromElfHeader(header);
spec.GetArchitecture().SetArchitecture(
eArchTypeELF, header.e_machine, sub_type, header.e_ident[EI_OSABI]);
if (spec.GetArchitecture().IsValid()) {
llvm::Triple::OSType ostype;
llvm::Triple::OSType spec_ostype =
spec.GetArchitecture().GetTriple().getOS();
LLDB_LOGF(log, "ObjectFileELF::%s file '%s' module OSABI: %s",
__FUNCTION__, file.GetPath().c_str(),
OSABIAsCString(header.e_ident[EI_OSABI]));
// Validate it is ok to remove GetOsFromOSABI
GetOsFromOSABI(header.e_ident[EI_OSABI], ostype);
assert(spec_ostype == ostype);
if (spec_ostype != llvm::Triple::OSType::UnknownOS) {
LLDB_LOGF(log,
"ObjectFileELF::%s file '%s' set ELF module OS type "
"from ELF header OSABI.",
__FUNCTION__, file.GetPath().c_str());
}
// When ELF file does not contain GNU build ID, the later code will
// calculate CRC32 with this data file_offset and
// length. It is important for Android zip .so file, which is a slice
// of a file, to not access the outside of the file slice range.
if (extractor_sp->GetByteSize() < length)
if (DataBufferSP data_sp = MapFileData(file, length, file_offset)) {
extractor_sp->SetData(data_sp);
}
// In case there is header extension in the section #0, the header we
// parsed above could have sentinel values for e_phnum, e_shnum, and
// e_shstrndx. In this case we need to reparse the header with a
// bigger data source to get the actual values.
if (header.HasHeaderExtension()) {
lldb::offset_t header_offset = 0;
header.Parse(*extractor_sp, &header_offset);
}
uint32_t gnu_debuglink_crc = 0;
std::string gnu_debuglink_file;
SectionHeaderColl section_headers;
lldb_private::UUID &uuid = spec.GetUUID();
GetSectionHeaderInfo(section_headers, *extractor_sp, header, uuid,
gnu_debuglink_file, gnu_debuglink_crc,
spec.GetArchitecture());
llvm::Triple &spec_triple = spec.GetArchitecture().GetTriple();
LLDB_LOGF(log,
"ObjectFileELF::%s file '%s' module set to triple: %s "
"(architecture %s)",
__FUNCTION__, file.GetPath().c_str(),
spec_triple.getTriple().c_str(),
spec.GetArchitecture().GetArchitectureName());
if (!uuid.IsValid()) {
uint32_t core_notes_crc = 0;
if (!gnu_debuglink_crc) {
LLDB_SCOPED_TIMERF("Calculating module crc32 %s with size %" PRIu64
" KiB",
file.GetFilename().str().c_str(),
(length - file_offset) / 1024);
// For core files - which usually don't happen to have a
// gnu_debuglink, and are pretty bulky - calculating whole
// contents crc32 would be too much of luxury. Thus we will need
// to fallback to something simpler.
if (header.e_type == llvm::ELF::ET_CORE) {
ProgramHeaderColl program_headers;
GetProgramHeaderInfo(program_headers, *extractor_sp, header);
core_notes_crc = CalculateELFNotesSegmentsCRC32(program_headers,
*extractor_sp);
} else {
gnu_debuglink_crc = calc_crc32(0, *extractor_sp);
}
}
using u32le = llvm::support::ulittle32_t;
if (gnu_debuglink_crc) {
// Use 4 bytes of crc from the .gnu_debuglink section.
u32le data(gnu_debuglink_crc);
uuid = UUID(&data, sizeof(data));
} else if (core_notes_crc) {
// Use 8 bytes - first 4 bytes for *magic* prefix, mainly to make
// it look different form .gnu_debuglink crc followed by 4 bytes
// of note segments crc.
u32le data[] = {u32le(g_core_uuid_magic), u32le(core_notes_crc)};
uuid = UUID(data, sizeof(data));
}
}
ModuleSpecList specs;
specs.Append(spec);
return specs;
}
}
}
return {};
}
// ObjectFile protocol
ObjectFileELF::ObjectFileELF(const lldb::ModuleSP &module_sp,
DataExtractorSP extractor_sp,
lldb::offset_t data_offset, const FileSpec *file,
lldb::offset_t file_offset, lldb::offset_t length)
: ObjectFile(module_sp, file, file_offset, length, extractor_sp,
data_offset) {
if (file)
m_file = *file;
}
ObjectFileELF::ObjectFileELF(const lldb::ModuleSP &module_sp,
DataBufferSP header_data_sp,
const lldb::ProcessSP &process_sp,
addr_t header_addr)
: ObjectFile(module_sp, process_sp, header_addr,
std::make_shared<DataExtractor>(header_data_sp)) {}
bool ObjectFileELF::IsExecutable() const {
return ((m_header.e_type & ET_EXEC) != 0) || (m_header.e_entry != 0);
}
bool ObjectFileELF::SetLoadAddress(Target &target, lldb::addr_t value,
bool value_is_offset) {
ModuleSP module_sp = GetModule();
if (module_sp) {
size_t num_loaded_sections = 0;
SectionList *section_list = GetSectionList();
if (section_list) {
if (!value_is_offset) {
addr_t base = GetBaseAddress().GetFileAddress();
if (base == LLDB_INVALID_ADDRESS)
return false;
value -= base;
}
const size_t num_sections = section_list->GetSize();
size_t sect_idx = 0;
for (sect_idx = 0; sect_idx < num_sections; ++sect_idx) {
// Iterate through the object file sections to find all of the sections
// that have SHF_ALLOC in their flag bits.
SectionSP section_sp(section_list->GetSectionAtIndex(sect_idx));
// PT_TLS segments can have the same p_vaddr and p_paddr as other
// PT_LOAD segments so we shouldn't load them. If we do load them, then
// the SectionLoadList will incorrectly fill in the instance variable
// SectionLoadList::m_addr_to_sect with the same address as a PT_LOAD
// segment and we won't be able to resolve addresses in the PT_LOAD
// segment whose p_vaddr entry matches that of the PT_TLS. Any variables
// that appear in the PT_TLS segments get resolved by the DWARF
// expressions. If this ever changes we will need to fix all object
// file plug-ins, but until then, we don't want PT_TLS segments to
// remove the entry from SectionLoadList::m_addr_to_sect when we call
// SetSectionLoadAddress() below.
if (section_sp->IsThreadSpecific())
continue;
if (section_sp->Test(SHF_ALLOC) ||
section_sp->GetType() == eSectionTypeContainer) {
lldb::addr_t load_addr = section_sp->GetFileAddress();
// We don't want to update the load address of a section with type
// eSectionTypeAbsoluteAddress as they already have the absolute load
// address already specified
if (section_sp->GetType() != eSectionTypeAbsoluteAddress)
load_addr += value;
// On 32-bit systems the load address have to fit into 4 bytes. The
// rest of the bytes are the overflow from the addition.
if (GetAddressByteSize() == 4)
load_addr &= 0xFFFFFFFF;
if (target.SetSectionLoadAddress(section_sp, load_addr))
++num_loaded_sections;
}
}
return num_loaded_sections > 0;
}
}
return false;
}
ByteOrder ObjectFileELF::GetByteOrder() const {
if (m_header.e_ident[EI_DATA] == ELFDATA2MSB)
return eByteOrderBig;
if (m_header.e_ident[EI_DATA] == ELFDATA2LSB)
return eByteOrderLittle;
return eByteOrderInvalid;
}
uint32_t ObjectFileELF::GetAddressByteSize() const {
return m_data_nsp->GetAddressByteSize();
}
AddressClass ObjectFileELF::GetAddressClass(addr_t file_addr) {
Symtab *symtab = GetSymtab();
if (!symtab)
return AddressClass::eUnknown;
// The address class is determined based on the symtab. Ask it from the
// object file what contains the symtab information.
ObjectFile *symtab_objfile = symtab->GetObjectFile();
if (symtab_objfile != nullptr && symtab_objfile != this)
return symtab_objfile->GetAddressClass(file_addr);
auto res = ObjectFile::GetAddressClass(file_addr);
if (res != AddressClass::eCode)
return res;
auto ub = m_address_class_map.upper_bound(file_addr);
if (ub == m_address_class_map.begin()) {
// No entry in the address class map before the address. Return default
// address class for an address in a code section.
return AddressClass::eCode;
}
// Move iterator to the address class entry preceding address
--ub;
return ub->second;
}
size_t ObjectFileELF::SectionIndex(const SectionHeaderCollIter &I) {
return std::distance(m_section_headers.begin(), I);
}
size_t ObjectFileELF::SectionIndex(const SectionHeaderCollConstIter &I) const {
return std::distance(m_section_headers.begin(), I);
}
bool ObjectFileELF::ParseHeader() {
lldb::offset_t offset = 0;
return m_header.Parse(*m_data_nsp, &offset);
}
UUID ObjectFileELF::GetUUID() {
if (m_uuid)
return m_uuid;
// Try loading note info from any PT_NOTE program headers. This is more
// friendly to ELF files that have no section headers, like ELF files that
// are loaded from memory.
for (const ELFProgramHeader &H : ProgramHeaders()) {
if (H.p_type == llvm::ELF::PT_NOTE) {
DataExtractor note_data = GetSegmentData(H);
if (note_data.GetByteSize()) {
lldb_private::ArchSpec arch_spec;
RefineModuleDetailsFromNote(note_data, arch_spec, m_uuid);
if (m_uuid)
return m_uuid;
}
}
}
// Need to parse the section list to get the UUIDs, so make sure that's been
// done.
if (!ParseSectionHeaders() && GetType() != ObjectFile::eTypeCoreFile)
return UUID();
if (!m_uuid) {
using u32le = llvm::support::ulittle32_t;
if (GetType() == ObjectFile::eTypeCoreFile) {
uint32_t core_notes_crc = 0;
if (!ParseProgramHeaders())
return UUID();
core_notes_crc =
CalculateELFNotesSegmentsCRC32(m_program_headers, *m_data_nsp);
if (core_notes_crc) {
// Use 8 bytes - first 4 bytes for *magic* prefix, mainly to make it
// look different form .gnu_debuglink crc - followed by 4 bytes of note
// segments crc.
u32le data[] = {u32le(g_core_uuid_magic), u32le(core_notes_crc)};
m_uuid = UUID(data, sizeof(data));
}
} else {
if (!m_gnu_debuglink_crc)
m_gnu_debuglink_crc = calc_crc32(0, *m_data_nsp);
if (m_gnu_debuglink_crc) {
// Use 4 bytes of crc from the .gnu_debuglink section.
u32le data(m_gnu_debuglink_crc);
m_uuid = UUID(&data, sizeof(data));
}
}
}
return m_uuid;
}
std::optional<FileSpec> ObjectFileELF::GetDebugLink() {
if (m_gnu_debuglink_file.empty())
return std::nullopt;
return FileSpec(m_gnu_debuglink_file);
}
uint32_t ObjectFileELF::GetDependentModules(FileSpecList &files) {
size_t num_modules = ParseDependentModules();
uint32_t num_specs = 0;
for (unsigned i = 0; i < num_modules; ++i) {
if (files.AppendIfUnique(m_filespec_up->GetFileSpecAtIndex(i)))
num_specs++;
}
return num_specs;
}
Address ObjectFileELF::GetImageInfoAddress(Target *target) {
if (!ParseDynamicSymbols())
return Address();
SectionList *section_list = GetSectionList();
if (!section_list)
return Address();
for (size_t i = 0; i < m_dynamic_symbols.size(); ++i) {
const ELFDynamic &symbol = m_dynamic_symbols[i].symbol;
if (symbol.d_tag != DT_DEBUG && symbol.d_tag != DT_MIPS_RLD_MAP &&
symbol.d_tag != DT_MIPS_RLD_MAP_REL)
continue;
// Compute the offset as the number of previous entries plus the size of
// d_tag.
const addr_t offset = (i * 2 + 1) * GetAddressByteSize();
const addr_t d_file_addr = m_dynamic_base_addr + offset;
Address d_addr;
if (!d_addr.ResolveAddressUsingFileSections(d_file_addr, GetSectionList()))
return Address();
if (symbol.d_tag == DT_DEBUG)
return d_addr;
// MIPS executables uses DT_MIPS_RLD_MAP_REL to support PIE. DT_MIPS_RLD_MAP
// exists in non-PIE.
if ((symbol.d_tag == DT_MIPS_RLD_MAP ||
symbol.d_tag == DT_MIPS_RLD_MAP_REL) &&
target) {
const addr_t d_load_addr = d_addr.GetLoadAddress(target);
if (d_load_addr == LLDB_INVALID_ADDRESS)
return Address();
Status error;
if (symbol.d_tag == DT_MIPS_RLD_MAP) {
// DT_MIPS_RLD_MAP tag stores an absolute address of the debug pointer.
Address addr;
if (target->ReadPointerFromMemory(Address(d_load_addr), error, addr,
true))
return addr;
}
if (symbol.d_tag == DT_MIPS_RLD_MAP_REL) {
// DT_MIPS_RLD_MAP_REL tag stores the offset to the debug pointer,
// relative to the address of the tag.
uint64_t rel_offset;
rel_offset = target->ReadUnsignedIntegerFromMemory(
Address(d_load_addr), GetAddressByteSize(), UINT64_MAX, error,
true);
if (error.Success() && rel_offset != UINT64_MAX) {
Address addr;
addr_t debug_ptr_address =
d_load_addr - GetAddressByteSize() + rel_offset;
addr.SetOffset(debug_ptr_address);
return addr;
}
}
}
}
return Address();
}
lldb_private::Address ObjectFileELF::GetEntryPointAddress() {
if (m_entry_point_address.IsValid())
return m_entry_point_address;
if (!ParseHeader() || !IsExecutable())
return m_entry_point_address;
SectionList *section_list = GetSectionList();
addr_t offset = m_header.e_entry;
if (!section_list)
m_entry_point_address.SetOffset(offset);
else
m_entry_point_address.ResolveAddressUsingFileSections(offset, section_list);
return m_entry_point_address;
}
Address ObjectFileELF::GetBaseAddress() {
if (GetType() == ObjectFile::eTypeObjectFile) {
for (SectionHeaderCollIter I = std::next(m_section_headers.begin());
I != m_section_headers.end(); ++I) {
const ELFSectionHeaderInfo &header = *I;
if (header.sh_flags & SHF_ALLOC)
return Address(GetSectionList()->FindSectionByID(SectionIndex(I)), 0);
}
return Address();
}
for (const auto &EnumPHdr : llvm::enumerate(ProgramHeaders())) {
const ELFProgramHeader &H = EnumPHdr.value();
if (H.p_type != PT_LOAD)
continue;
return Address(
GetSectionList()->FindSectionByID(SegmentID(EnumPHdr.index())), 0);
}
return Address();
}
FileSpecList ObjectFileELF::GetReExportedLibraries() {
FileSpecList filtees;
if (!ParseDynamicSymbols())
return filtees;
// Multiple DT_FILTER / DT_AUXILIARY entries are permitted; the dynamic
// linker searches the filtees in the order the entries appear in the
// dynamic section, so preserve that order here.
for (const auto &entry : m_dynamic_symbols) {
if (entry.symbol.d_tag != DT_FILTER && entry.symbol.d_tag != DT_AUXILIARY)
continue;
if (!entry.name.empty())
filtees.EmplaceBack(entry.name);
}
return filtees;
}
size_t ObjectFileELF::ParseDependentModules() {
if (m_filespec_up)
return m_filespec_up->GetSize();
m_filespec_up = std::make_unique<FileSpecList>();
if (ParseDynamicSymbols()) {
for (const auto &entry : m_dynamic_symbols) {
if (entry.symbol.d_tag != DT_NEEDED)
continue;
if (!entry.name.empty()) {
FileSpec file_spec(entry.name);
FileSystem::Instance().Resolve(file_spec);
m_filespec_up->Append(file_spec);
}
}
}
return m_filespec_up->GetSize();
}
// GetProgramHeaderInfo
size_t ObjectFileELF::GetProgramHeaderInfo(ProgramHeaderColl &program_headers,
DataExtractor &object_data,
const ELFHeader &header) {
// We have already parsed the program headers
if (!program_headers.empty())
return program_headers.size();
// If there are no program headers to read we are done.
if (header.e_phnum == 0)
return 0;
program_headers.resize(header.e_phnum);
if (program_headers.size() != header.e_phnum)
return 0;
const size_t ph_size = header.e_phnum * header.e_phentsize;
const elf_off ph_offset = header.e_phoff;
DataExtractor data;
if (data.SetData(object_data, ph_offset, ph_size) != ph_size)
return 0;
uint32_t idx;
lldb::offset_t offset;
for (idx = 0, offset = 0; idx < header.e_phnum; ++idx) {
if (!program_headers[idx].Parse(data, &offset))
break;
}
if (idx < program_headers.size())
program_headers.resize(idx);
return program_headers.size();
}
// ParseProgramHeaders
bool ObjectFileELF::ParseProgramHeaders() {
return GetProgramHeaderInfo(m_program_headers, *m_data_nsp, m_header) != 0;
}
lldb_private::Status
ObjectFileELF::RefineModuleDetailsFromNote(lldb_private::DataExtractor &data,
lldb_private::ArchSpec &arch_spec,
lldb_private::UUID &uuid) {
Log *log = GetLog(LLDBLog::Modules);
Status error;
lldb::offset_t offset = 0;
while (true) {
// Parse the note header. If this fails, bail out.
const lldb::offset_t note_offset = offset;
ELFNote note = ELFNote();
if (!note.Parse(data, &offset)) {
// We're done.
return error;
}
LLDB_LOGF(log, "ObjectFileELF::%s parsing note name='%s', type=%" PRIu32,
__FUNCTION__, note.n_name.c_str(), note.n_type);
// Process FreeBSD ELF notes.
if ((note.n_name == LLDB_NT_OWNER_FREEBSD) &&
(note.n_type == LLDB_NT_FREEBSD_ABI_TAG) &&
(note.n_descsz == LLDB_NT_FREEBSD_ABI_SIZE)) {
// Pull out the min version info.
uint32_t version_info;
if (data.GetU32(&offset, &version_info, 1) == nullptr) {
error =
Status::FromErrorString("failed to read FreeBSD ABI note payload");
return error;
}
// Convert the version info into a major/minor number.
const uint32_t version_major = version_info / 100000;
const uint32_t version_minor = (version_info / 1000) % 100;
char os_name[32];
snprintf(os_name, sizeof(os_name), "freebsd%" PRIu32 ".%" PRIu32,
version_major, version_minor);
// Set the elf OS version to FreeBSD. Also clear the vendor.
arch_spec.GetTriple().setOSName(os_name);
arch_spec.GetTriple().setVendor(llvm::Triple::VendorType::UnknownVendor);
LLDB_LOGF(log,
"ObjectFileELF::%s detected FreeBSD %" PRIu32 ".%" PRIu32
".%" PRIu32,
__FUNCTION__, version_major, version_minor,
static_cast<uint32_t>(version_info % 1000));
}
// Process GNU ELF notes.
else if (note.n_name == LLDB_NT_OWNER_GNU) {
switch (note.n_type) {
case LLDB_NT_GNU_ABI_TAG:
if (note.n_descsz == LLDB_NT_GNU_ABI_SIZE) {
// Pull out the min OS version supporting the ABI.
uint32_t version_info[4];
if (data.GetU32(&offset, &version_info[0], note.n_descsz / 4) ==
nullptr) {
error =
Status::FromErrorString("failed to read GNU ABI note payload");
return error;
}
// Set the OS per the OS field.
switch (version_info[0]) {
case LLDB_NT_GNU_ABI_OS_LINUX:
arch_spec.GetTriple().setOS(llvm::Triple::OSType::Linux);
arch_spec.GetTriple().setVendor(
llvm::Triple::VendorType::UnknownVendor);
LLDB_LOGF(log,
"ObjectFileELF::%s detected Linux, min version %" PRIu32
".%" PRIu32 ".%" PRIu32,
__FUNCTION__, version_info[1], version_info[2],
version_info[3]);
// FIXME we have the minimal version number, we could be propagating
// that. version_info[1] = OS Major, version_info[2] = OS Minor,
// version_info[3] = Revision.
break;
case LLDB_NT_GNU_ABI_OS_HURD:
arch_spec.GetTriple().setOS(llvm::Triple::OSType::UnknownOS);
arch_spec.GetTriple().setVendor(
llvm::Triple::VendorType::UnknownVendor);
LLDB_LOGF(log,
"ObjectFileELF::%s detected Hurd (unsupported), min "
"version %" PRIu32 ".%" PRIu32 ".%" PRIu32,
__FUNCTION__, version_info[1], version_info[2],
version_info[3]);
break;
case LLDB_NT_GNU_ABI_OS_SOLARIS:
arch_spec.GetTriple().setOS(llvm::Triple::OSType::Solaris);
arch_spec.GetTriple().setVendor(
llvm::Triple::VendorType::UnknownVendor);
LLDB_LOGF(log,
"ObjectFileELF::%s detected Solaris, min version %" PRIu32
".%" PRIu32 ".%" PRIu32,
__FUNCTION__, version_info[1], version_info[2],
version_info[3]);
break;
default:
LLDB_LOGF(log,
"ObjectFileELF::%s unrecognized OS in note, id %" PRIu32
", min version %" PRIu32 ".%" PRIu32 ".%" PRIu32,
__FUNCTION__, version_info[0], version_info[1],
version_info[2], version_info[3]);
break;
}
}
break;
case LLDB_NT_GNU_BUILD_ID_TAG:
// Only bother processing this if we don't already have the uuid set.
if (!uuid.IsValid()) {
// 16 bytes is UUID|MD5, 20 bytes is SHA1. Other linkers may produce a
// build-id of a different length. Accept it as long as it's at least
// 4 bytes as it will be better than our own crc32.
if (note.n_descsz >= 4) {
if (const uint8_t *buf = data.PeekData(offset, note.n_descsz)) {
// Save the build id as the UUID for the module.
uuid = UUID(buf, note.n_descsz);
} else {
error = Status::FromErrorString(
"failed to read GNU_BUILD_ID note payload");
return error;
}
}
}
break;
}
if (arch_spec.IsMIPS() &&
arch_spec.GetTriple().getOS() == llvm::Triple::OSType::UnknownOS)
// The note.n_name == LLDB_NT_OWNER_GNU is valid for Linux platform
arch_spec.GetTriple().setOS(llvm::Triple::OSType::Linux);
}
// Process NetBSD ELF executables and shared libraries
else if ((note.n_name == LLDB_NT_OWNER_NETBSD) &&
(note.n_type == LLDB_NT_NETBSD_IDENT_TAG) &&
(note.n_descsz == LLDB_NT_NETBSD_IDENT_DESCSZ) &&
(note.n_namesz == LLDB_NT_NETBSD_IDENT_NAMESZ)) {
// Pull out the version info.
uint32_t version_info;
if (data.GetU32(&offset, &version_info, 1) == nullptr) {
error =
Status::FromErrorString("failed to read NetBSD ABI note payload");
return error;
}
// Convert the version info into a major/minor/patch number.
// #define __NetBSD_Version__ MMmmrrpp00
//
// M = major version
// m = minor version; a minor number of 99 indicates current.
// r = 0 (since NetBSD 3.0 not used)
// p = patchlevel
const uint32_t version_major = version_info / 100000000;
const uint32_t version_minor = (version_info % 100000000) / 1000000;
const uint32_t version_patch = (version_info % 10000) / 100;
// Set the elf OS version to NetBSD. Also clear the vendor.
arch_spec.GetTriple().setOSName(
llvm::formatv("netbsd{0}.{1}.{2}", version_major, version_minor,
version_patch).str());
arch_spec.GetTriple().setVendor(llvm::Triple::VendorType::UnknownVendor);
}
// Process NetBSD ELF core(5) notes
else if ((note.n_name == LLDB_NT_OWNER_NETBSDCORE) &&
(note.n_type == LLDB_NT_NETBSD_PROCINFO)) {
// Set the elf OS version to NetBSD. Also clear the vendor.
arch_spec.GetTriple().setOS(llvm::Triple::OSType::NetBSD);
arch_spec.GetTriple().setVendor(llvm::Triple::VendorType::UnknownVendor);
}
// Process OpenBSD ELF notes.
else if (note.n_name == LLDB_NT_OWNER_OPENBSD) {
// Set the elf OS version to OpenBSD. Also clear the vendor.
arch_spec.GetTriple().setOS(llvm::Triple::OSType::OpenBSD);
arch_spec.GetTriple().setVendor(llvm::Triple::VendorType::UnknownVendor);
} else if (note.n_name == LLDB_NT_OWNER_ANDROID) {
arch_spec.GetTriple().setOS(llvm::Triple::OSType::Linux);
arch_spec.GetTriple().setEnvironment(
llvm::Triple::EnvironmentType::Android);
} else if (note.n_name == LLDB_NT_OWNER_LINUX) {
// This is sometimes found in core files and usually contains extended
// register info
arch_spec.GetTriple().setOS(llvm::Triple::OSType::Linux);
} else if (note.n_name == LLDB_NT_OWNER_CORE) {
// Parse the NT_FILE to look for stuff in paths to shared libraries
// The contents look like this in a 64 bit ELF core file:
//
// count = 0x000000000000000a (10)
// page_size = 0x0000000000001000 (4096)
// Index start end file_ofs path
// ===== ------------------ ------------------ ------------------ -------------------------------------
// [ 0] 0x0000000000401000 0x0000000000000000 /tmp/a.out
// [ 1] 0x0000000000600000 0x0000000000601000 0x0000000000000000 /tmp/a.out
// [ 2] 0x0000000000601000 0x0000000000602000 0x0000000000000001 /tmp/a.out
// [ 3] 0x00007fa79c9ed000 0x00007fa79cba8000 0x0000000000000000 /lib/x86_64-linux-gnu/libc-2.19.so
// [ 4] 0x00007fa79cba8000 0x00007fa79cda7000 0x00000000000001bb /lib/x86_64-linux-gnu/libc-2.19.so
// [ 5] 0x00007fa79cda7000 0x00007fa79cdab000 0x00000000000001ba /lib/x86_64-linux-gnu/libc-2.19.so
// [ 6] 0x00007fa79cdab000 0x00007fa79cdad000 0x00000000000001be /lib/x86_64-linux-gnu/libc-2.19.so
// [ 7] 0x00007fa79cdb2000 0x00007fa79cdd5000 0x0000000000000000 /lib/x86_64-linux-gnu/ld-2.19.so
// [ 8] 0x00007fa79cfd4000 0x00007fa79cfd5000 0x0000000000000022 /lib/x86_64-linux-gnu/ld-2.19.so
// [ 9] 0x00007fa79cfd5000 0x00007fa79cfd6000 0x0000000000000023 /lib/x86_64-linux-gnu/ld-2.19.so
//
// In the 32 bit ELFs the count, page_size, start, end, file_ofs are
// uint32_t.
//
// For reference: see readelf source code (in binutils).
if (note.n_type == NT_FILE) {
uint64_t count = data.GetAddress(&offset);
const char *cstr;
data.GetAddress(&offset); // Skip page size
offset += count * 3 *
data.GetAddressByteSize(); // Skip all start/end/file_ofs
for (size_t i = 0; i < count; ++i) {
cstr = data.GetCStr(&offset);
if (cstr == nullptr) {
error = Status::FromErrorStringWithFormat(
"ObjectFileELF::%s trying to read "
"at an offset after the end "
"(GetCStr returned nullptr)",
__FUNCTION__);
return error;
}
llvm::StringRef path(cstr);
if (path.contains("/lib/x86_64-linux-gnu") || path.contains("/lib/i386-linux-gnu")) {
arch_spec.GetTriple().setOS(llvm::Triple::OSType::Linux);
break;
}
}
if (arch_spec.IsMIPS() &&
arch_spec.GetTriple().getOS() == llvm::Triple::OSType::UnknownOS)
// In case of MIPSR6, the LLDB_NT_OWNER_GNU note is missing for some
// cases (e.g. compile with -nostdlib) Hence set OS to Linux
arch_spec.GetTriple().setOS(llvm::Triple::OSType::Linux);
}
}
// Calculate the offset of the next note just in case "offset" has been
// used to poke at the contents of the note data
offset = note_offset + note.GetByteSize();
}
return error;
}
void ObjectFileELF::ParseARMAttributes(DataExtractor &data, uint64_t length,
ArchSpec &arch_spec) {
lldb::offset_t Offset = 0;
uint8_t FormatVersion = data.GetU8(&Offset);
if (FormatVersion != llvm::ELFAttrs::Format_Version)
return;
Offset = Offset + sizeof(uint32_t); // Section Length
llvm::StringRef VendorName = data.GetCStr(&Offset);
if (VendorName != "aeabi")
return;
if (arch_spec.GetTriple().getEnvironment() ==
llvm::Triple::UnknownEnvironment)
arch_spec.GetTriple().setEnvironment(llvm::Triple::EABI);
while (Offset < length) {
uint8_t Tag = data.GetU8(&Offset);
uint32_t Size = data.GetU32(&Offset);
if (Tag != llvm::ARMBuildAttrs::File || Size == 0)
continue;
while (Offset < length) {
uint64_t Tag = data.GetULEB128(&Offset);
switch (Tag) {
default:
if (Tag < 32)
data.GetULEB128(&Offset);
else if (Tag % 2 == 0)
data.GetULEB128(&Offset);
else
data.GetCStr(&Offset);
break;
case llvm::ARMBuildAttrs::CPU_raw_name:
case llvm::ARMBuildAttrs::CPU_name:
data.GetCStr(&Offset);
break;
case llvm::ARMBuildAttrs::ABI_VFP_args: {
uint64_t VFPArgs = data.GetULEB128(&Offset);
if (VFPArgs == llvm::ARMBuildAttrs::BaseAAPCS) {
if (arch_spec.GetTriple().getEnvironment() ==
llvm::Triple::UnknownEnvironment ||
arch_spec.GetTriple().getEnvironment() == llvm::Triple::EABIHF)
arch_spec.GetTriple().setEnvironment(llvm::Triple::EABI);
arch_spec.SetFlags(ArchSpec::eARM_abi_soft_float);
} else if (VFPArgs == llvm::ARMBuildAttrs::HardFPAAPCS) {
if (arch_spec.GetTriple().getEnvironment() ==
llvm::Triple::UnknownEnvironment ||
arch_spec.GetTriple().getEnvironment() == llvm::Triple::EABI)
arch_spec.GetTriple().setEnvironment(llvm::Triple::EABIHF);
arch_spec.SetFlags(ArchSpec::eARM_abi_hard_float);
}
break;
}
}
}
}
}
static std::optional<lldb::offset_t>
FindSubSectionOffsetByName(const DataExtractor &data, lldb::offset_t offset,
uint32_t length, llvm::StringRef name) {
uint32_t section_length = 0;
llvm::StringRef section_name;
do {
offset += section_length;
// Sub-section's size and name are included in the total sub-section length.
// Don't shift the offset here, so it will point at the beginning of the
// sub-section and could be used as a return value.
auto tmp_offset = offset;
section_length = data.GetU32(&tmp_offset);
section_name = data.GetCStr(&tmp_offset);
} while (section_name != name && offset + section_length < length);
if (section_name == name)
return offset;
return std::nullopt;
}
static std::optional<lldb::offset_t>
FindSubSubSectionOffsetByTag(const DataExtractor &data, lldb::offset_t offset,
unsigned tag) {
// Consume a sub-section size and name to shift the offset at the beginning of
// the sub-sub-sections list.
auto parent_section_length = data.GetU32(&offset);
data.GetCStr(&offset);
auto parent_section_end_offset = offset + parent_section_length;
uint32_t section_length = 0;
unsigned section_tag = 0;
do {
offset += section_length;
// Similar to sub-section sub-sub-section's tag and size are included in the
// total sub-sub-section length.
auto tmp_offset = offset;
section_tag = data.GetULEB128(&tmp_offset);
section_length = data.GetU32(&tmp_offset);
} while (section_tag != tag &&
offset + section_length < parent_section_end_offset);
if (section_tag == tag)
return offset;
return std::nullopt;
}
static std::optional<std::variant<uint64_t, llvm::StringRef>>
GetAttributeValueByTag(const DataExtractor &data, lldb::offset_t offset,
unsigned tag) {
// Consume a sub-sub-section tag and size to shift the offset at the beginning
// of the attribute list.
data.GetULEB128(&offset);
auto parent_section_length = data.GetU32(&offset);
auto parent_section_end_offset = offset + parent_section_length;
std::variant<uint64_t, llvm::StringRef> result;
unsigned attribute_tag = 0;
do {
attribute_tag = data.GetULEB128(&offset);
// From the riscv psABI document:
// RISC-V attributes have a string value if the tag number is odd and an
// integer value if the tag number is even.
if (attribute_tag % 2)
result = data.GetCStr(&offset);
else
result = data.GetULEB128(&offset);
} while (attribute_tag != tag && offset < parent_section_end_offset);
if (attribute_tag == tag)
return result;
return std::nullopt;
}
void ObjectFileELF::ParseRISCVAttributes(const DataExtractor &data,
uint64_t length, ArchSpec &arch_spec) {
Log *log = GetLog(LLDBLog::Modules);
lldb::offset_t offset = 0;
// According to the riscv psABI, the .riscv.attributes section has the
// following hierarchical structure:
//
// Section:
// .riscv.attributes {
// - (uint8_t) format
// - Sub-Section 1 {
// * (uint32_t) length
// * (c_str) name
// * Sub-Sub-Section 1.1 {
// > (uleb128_t) tag
// > (uint32_t) length
// > (uleb128_t) attribute_tag_1.1.1
// $ (c_str or uleb128_t) value
// > (uleb128_t) attribute_tag_1.1.2
// $ (c_str or uleb128_t) value
// ...
// Other attributes...
// ...
// > (uleb128_t) attribute_tag_1.1.N
// $ (c_str or uleb128_t) value
// }
// * Sub-Sub-Section 1.2 {
// ...
// Sub-Sub-Section structure...
// ...
// }
// ...
// Other sub-sub-sections...
// ...
// }
// - Sub-Section 2 {
// ...
// Sub-Section structure...
// ...
// }
// ...
// Other sub-sections...
// ...
// }
uint8_t format_version = data.GetU8(&offset);
if (format_version != llvm::ELFAttrs::Format_Version)
return;
auto subsection_or_opt =
FindSubSectionOffsetByName(data, offset, length, "riscv");
if (!subsection_or_opt) {
LLDB_LOGF(log,
"ObjectFileELF::%s Ill-formed .riscv.attributes section: "
"mandatory 'riscv' sub-section was not preserved",
__FUNCTION__);
return;
}
auto subsubsection_or_opt = FindSubSubSectionOffsetByTag(
data, *subsection_or_opt, llvm::ELFAttrs::File);
if (!subsubsection_or_opt)
return;
auto value_or_opt = GetAttributeValueByTag(data, *subsubsection_or_opt,
llvm::RISCVAttrs::ARCH);
if (!value_or_opt)
return;
auto normalized_isa_info = llvm::RISCVISAInfo::parseNormalizedArchString(
std::get<llvm::StringRef>(*value_or_opt));
if (llvm::errorToBool(normalized_isa_info.takeError()))
return;
llvm::SubtargetFeatures features;
features.addFeaturesVector((*normalized_isa_info)->toFeatures());
arch_spec.SetSubtargetFeatures(std::move(features));
// Additional verification of the arch string. This is primarily needed to
// warn users if the executable file contains conflicting RISC-V extensions
// that could lead to invalid disassembler output.
auto isa_info = llvm::RISCVISAInfo::parseArchString(
std::get<llvm::StringRef>(*value_or_opt),
/* EnableExperimentalExtension=*/true);
if (auto error = isa_info.takeError()) {
StreamString ss;
ss << "the .riscv.attributes section contains an invalid RISC-V arch "
"string: "
<< llvm::toString(std::move(error))
<< "\n\tThis could result in misleading disassembler output\n";
Debugger::ReportWarning(ss.GetString().str());
}
}
// GetSectionHeaderInfo
size_t ObjectFileELF::GetSectionHeaderInfo(SectionHeaderColl &section_headers,
DataExtractor &object_data,
const elf::ELFHeader &header,
lldb_private::UUID &uuid,
std::string &gnu_debuglink_file,
uint32_t &gnu_debuglink_crc,
ArchSpec &arch_spec) {
// Don't reparse the section headers if we already did that.
if (!section_headers.empty())
return section_headers.size();
// Only initialize the arch_spec to okay defaults if they're not already set.
// We'll refine this with note data as we parse the notes.
if (arch_spec.GetTriple().getOS() == llvm::Triple::OSType::UnknownOS) {
llvm::Triple::OSType ostype;
llvm::Triple::OSType spec_ostype;
const uint32_t sub_type = subTypeFromElfHeader(header);
arch_spec.SetArchitecture(eArchTypeELF, header.e_machine, sub_type,
header.e_ident[EI_OSABI]);
// Validate if it is ok to remove GetOsFromOSABI. Note, that now the OS is
// determined based on EI_OSABI flag and the info extracted from ELF notes
// (see RefineModuleDetailsFromNote). However in some cases that still
// might be not enough: for example a shared library might not have any
// notes at all and have EI_OSABI flag set to System V, as result the OS
// will be set to UnknownOS.
GetOsFromOSABI(header.e_ident[EI_OSABI], ostype);
spec_ostype = arch_spec.GetTriple().getOS();
assert(spec_ostype == ostype);
UNUSED_IF_ASSERT_DISABLED(spec_ostype);
}
if (arch_spec.GetMachine() == llvm::Triple::mips ||
arch_spec.GetMachine() == llvm::Triple::mipsel ||
arch_spec.GetMachine() == llvm::Triple::mips64 ||
arch_spec.GetMachine() == llvm::Triple::mips64el) {
switch (header.e_flags & llvm::ELF::EF_MIPS_ARCH_ASE) {
case llvm::ELF::EF_MIPS_MICROMIPS:
arch_spec.SetFlags(ArchSpec::eMIPSAse_micromips);
break;
case llvm::ELF::EF_MIPS_ARCH_ASE_M16:
arch_spec.SetFlags(ArchSpec::eMIPSAse_mips16);
break;
case llvm::ELF::EF_MIPS_ARCH_ASE_MDMX:
arch_spec.SetFlags(ArchSpec::eMIPSAse_mdmx);
break;
default:
break;
}
}
if (arch_spec.GetMachine() == llvm::Triple::arm ||
arch_spec.GetMachine() == llvm::Triple::thumb) {
if (header.e_flags & llvm::ELF::EF_ARM_SOFT_FLOAT)
arch_spec.SetFlags(ArchSpec::eARM_abi_soft_float);
else if (header.e_flags & llvm::ELF::EF_ARM_VFP_FLOAT)
arch_spec.SetFlags(ArchSpec::eARM_abi_hard_float);
}
if (arch_spec.GetMachine() == llvm::Triple::riscv32 ||
arch_spec.GetMachine() == llvm::Triple::riscv64) {
uint32_t flags = arch_spec.GetFlags();
if (header.e_flags & llvm::ELF::EF_RISCV_RVC)
flags |= ArchSpec::eRISCV_rvc;
if (header.e_flags & llvm::ELF::EF_RISCV_RVE)
flags |= ArchSpec::eRISCV_rve;
if ((header.e_flags & llvm::ELF::EF_RISCV_FLOAT_ABI_SINGLE) ==
llvm::ELF::EF_RISCV_FLOAT_ABI_SINGLE)
flags |= ArchSpec::eRISCV_float_abi_single;
else if ((header.e_flags & llvm::ELF::EF_RISCV_FLOAT_ABI_DOUBLE) ==
llvm::ELF::EF_RISCV_FLOAT_ABI_DOUBLE)
flags |= ArchSpec::eRISCV_float_abi_double;
else if ((header.e_flags & llvm::ELF::EF_RISCV_FLOAT_ABI_QUAD) ==
llvm::ELF::EF_RISCV_FLOAT_ABI_QUAD)
flags |= ArchSpec::eRISCV_float_abi_quad;
arch_spec.SetFlags(flags);
}
if (arch_spec.GetMachine() == llvm::Triple::loongarch32 ||
arch_spec.GetMachine() == llvm::Triple::loongarch64) {
uint32_t flags = arch_spec.GetFlags();
switch (header.e_flags & llvm::ELF::EF_LOONGARCH_ABI_MODIFIER_MASK) {
case llvm::ELF::EF_LOONGARCH_ABI_SINGLE_FLOAT:
flags |= ArchSpec::eLoongArch_abi_single_float;
break;
case llvm::ELF::EF_LOONGARCH_ABI_DOUBLE_FLOAT:
flags |= ArchSpec::eLoongArch_abi_double_float;
break;
case llvm::ELF::EF_LOONGARCH_ABI_SOFT_FLOAT:
break;
}
arch_spec.SetFlags(flags);
}
// If there are no section headers we are done.
if (header.e_shnum == 0)
return 0;
Log *log = GetLog(LLDBLog::Modules);
section_headers.resize(header.e_shnum);
if (section_headers.size() != header.e_shnum)
return 0;
const size_t sh_size = header.e_shnum * header.e_shentsize;
const elf_off sh_offset = header.e_shoff;
DataExtractor sh_data;
if (sh_data.SetData(object_data, sh_offset, sh_size) != sh_size)
return 0;
uint32_t idx;
lldb::offset_t offset;
for (idx = 0, offset = 0; idx < header.e_shnum; ++idx) {
if (!section_headers[idx].Parse(sh_data, &offset))
break;
}
if (idx < section_headers.size())
section_headers.resize(idx);
const unsigned strtab_idx = header.e_shstrndx;
if (strtab_idx && strtab_idx < section_headers.size()) {
const ELFSectionHeaderInfo &sheader = section_headers[strtab_idx];
const size_t byte_size = sheader.sh_size;
const Elf64_Off offset = sheader.sh_offset;
lldb_private::DataExtractor shstr_data;
if (shstr_data.SetData(object_data, offset, byte_size) == byte_size) {
for (SectionHeaderCollIter I = section_headers.begin();
I != section_headers.end(); ++I) {
static constexpr llvm::StringLiteral g_sect_name_gnu_debuglink(
".gnu_debuglink");
const ELFSectionHeaderInfo &sheader = *I;
const uint64_t section_size =
sheader.sh_type == SHT_NOBITS ? 0 : sheader.sh_size;
llvm::StringRef name = shstr_data.PeekCStr(I->sh_name).value_or("");
I->section_name = name.str();
if (arch_spec.IsMIPS()) {
uint32_t arch_flags = arch_spec.GetFlags();
DataExtractor data;
if (sheader.sh_type == SHT_MIPS_ABIFLAGS) {
if (section_size && (data.SetData(object_data, sheader.sh_offset,
section_size) == section_size)) {
// MIPS ASE Mask is at offset 12 in MIPS.abiflags section
lldb::offset_t offset = 12; // MIPS ABI Flags Version: 0
arch_flags |= data.GetU32(&offset);
// The floating point ABI is at offset 7
offset = 7;
switch (data.GetU8(&offset)) {
case llvm::Mips::Val_GNU_MIPS_ABI_FP_ANY:
arch_flags |= lldb_private::ArchSpec::eMIPS_ABI_FP_ANY;
break;
case llvm::Mips::Val_GNU_MIPS_ABI_FP_DOUBLE:
arch_flags |= lldb_private::ArchSpec::eMIPS_ABI_FP_DOUBLE;
break;
case llvm::Mips::Val_GNU_MIPS_ABI_FP_SINGLE:
arch_flags |= lldb_private::ArchSpec::eMIPS_ABI_FP_SINGLE;
break;
case llvm::Mips::Val_GNU_MIPS_ABI_FP_SOFT:
arch_flags |= lldb_private::ArchSpec::eMIPS_ABI_FP_SOFT;
break;
case llvm::Mips::Val_GNU_MIPS_ABI_FP_OLD_64:
arch_flags |= lldb_private::ArchSpec::eMIPS_ABI_FP_OLD_64;
break;
case llvm::Mips::Val_GNU_MIPS_ABI_FP_XX:
arch_flags |= lldb_private::ArchSpec::eMIPS_ABI_FP_XX;
break;
case llvm::Mips::Val_GNU_MIPS_ABI_FP_64:
arch_flags |= lldb_private::ArchSpec::eMIPS_ABI_FP_64;
break;
case llvm::Mips::Val_GNU_MIPS_ABI_FP_64A:
arch_flags |= lldb_private::ArchSpec::eMIPS_ABI_FP_64A;
break;
}
}
}
// Settings appropriate ArchSpec ABI Flags
switch (header.e_flags & llvm::ELF::EF_MIPS_ABI) {
case llvm::ELF::EF_MIPS_ABI_O32:
arch_flags |= lldb_private::ArchSpec::eMIPSABI_O32;
break;
case EF_MIPS_ABI_O64:
arch_flags |= lldb_private::ArchSpec::eMIPSABI_O64;
break;
case EF_MIPS_ABI_EABI32:
arch_flags |= lldb_private::ArchSpec::eMIPSABI_EABI32;
break;
case EF_MIPS_ABI_EABI64:
arch_flags |= lldb_private::ArchSpec::eMIPSABI_EABI64;
break;
default:
// ABI Mask doesn't cover N32 and N64 ABI.
if (header.e_ident[EI_CLASS] == llvm::ELF::ELFCLASS64)
arch_flags |= lldb_private::ArchSpec::eMIPSABI_N64;
else if (header.e_flags & llvm::ELF::EF_MIPS_ABI2)
arch_flags |= lldb_private::ArchSpec::eMIPSABI_N32;
break;
}
arch_spec.SetFlags(arch_flags);
}
if (arch_spec.GetMachine() == llvm::Triple::arm ||
arch_spec.GetMachine() == llvm::Triple::thumb) {
DataExtractor data;
if (sheader.sh_type == SHT_ARM_ATTRIBUTES && section_size != 0 &&
data.SetData(object_data, sheader.sh_offset, section_size) == section_size)
ParseARMAttributes(data, section_size, arch_spec);
}
if (arch_spec.GetTriple().isRISCV()) {
DataExtractor data;
if (sheader.sh_type == llvm::ELF::SHT_RISCV_ATTRIBUTES &&
section_size != 0 &&
data.SetData(object_data, sheader.sh_offset, section_size) ==
section_size)
ParseRISCVAttributes(data, section_size, arch_spec);
}
if (name == g_sect_name_gnu_debuglink) {
DataExtractor data;
if (section_size && (data.SetData(object_data, sheader.sh_offset,
section_size) == section_size)) {
lldb::offset_t gnu_debuglink_offset = 0;
if (const char *file = data.GetCStr(&gnu_debuglink_offset)) {
gnu_debuglink_file = file;
gnu_debuglink_offset = llvm::alignTo(gnu_debuglink_offset, 4);
data.GetU32(&gnu_debuglink_offset, &gnu_debuglink_crc, 1);
}
}
}
// Process ELF note section entries.
bool is_note_header = (sheader.sh_type == SHT_NOTE);
// The section header ".note.android.ident" is stored as a
// PROGBITS type header but it is actually a note header.
static constexpr llvm::StringLiteral g_sect_name_android_ident(
".note.android.ident");
if (!is_note_header && name == g_sect_name_android_ident)
is_note_header = true;
if (is_note_header) {
// Allow notes to refine module info.
DataExtractor data;
if (section_size && (data.SetData(object_data, sheader.sh_offset,
section_size) == section_size)) {
Status error = RefineModuleDetailsFromNote(data, arch_spec, uuid);
if (error.Fail()) {
LLDB_LOGF(log, "ObjectFileELF::%s ELF note processing failed: %s",
__FUNCTION__, error.AsCString());
}
}
}
}
// Make any unknown triple components to be unspecified unknowns.
if (arch_spec.GetTriple().getVendor() == llvm::Triple::UnknownVendor)
arch_spec.GetTriple().setVendorName(llvm::StringRef());
if (arch_spec.GetTriple().getOS() == llvm::Triple::UnknownOS)
arch_spec.GetTriple().setOSName(llvm::StringRef());
return section_headers.size();
}
}
section_headers.clear();
return 0;
}
llvm::StringRef
ObjectFileELF::StripLinkerSymbolAnnotations(llvm::StringRef symbol_name) const {
size_t pos = symbol_name.find('@');
return symbol_name.substr(0, pos);
}
// ParseSectionHeaders
size_t ObjectFileELF::ParseSectionHeaders() {
return GetSectionHeaderInfo(m_section_headers, *m_data_nsp, m_header, m_uuid,
m_gnu_debuglink_file, m_gnu_debuglink_crc,
m_arch_spec);
}
const ObjectFileELF::ELFSectionHeaderInfo *
ObjectFileELF::GetSectionHeaderByIndex(lldb::user_id_t id) {
if (!ParseSectionHeaders())
return nullptr;
if (id < m_section_headers.size())
return &m_section_headers[id];
return nullptr;
}
lldb::user_id_t ObjectFileELF::GetSectionIndexByName(llvm::StringRef name) {
if (name.empty() || !ParseSectionHeaders())
return 0;
for (size_t i = 1; i < m_section_headers.size(); ++i)
if (m_section_headers[i].section_name == name)
return i;
return 0;
}
static SectionType GetSectionTypeFromName(llvm::StringRef Name) {
if (Name.consume_front(".debug_"))
return ObjectFile::GetDWARFSectionTypeFromName(Name);
return llvm::StringSwitch<SectionType>(Name)
.Case(".ARM.exidx", eSectionTypeARMexidx)
.Case(".ARM.extab", eSectionTypeARMextab)
.Case(".ctf", eSectionTypeDebug)
.Cases({".data", ".tdata"}, eSectionTypeData)
.Case(".eh_frame", eSectionTypeEHFrame)
.Case(".gnu_debugaltlink", eSectionTypeDWARFGNUDebugAltLink)
.Case(".gosymtab", eSectionTypeGoSymtab)
.Case(".text", eSectionTypeCode)
.Case(".lldbsummaries", lldb::eSectionTypeLLDBTypeSummaries)
.Case(".lldbformatters", lldb::eSectionTypeLLDBFormatters)
.Case(".swift_ast", eSectionTypeSwiftModules)
.Default(eSectionTypeOther);
}
SectionType ObjectFileELF::GetSectionType(const ELFSectionHeaderInfo &H) const {
switch (H.sh_type) {
case SHT_PROGBITS:
if (H.sh_flags & SHF_EXECINSTR)
return eSectionTypeCode;
break;
case SHT_NOBITS:
if (H.sh_flags & SHF_ALLOC)
return eSectionTypeZeroFill;
break;
case SHT_SYMTAB:
return eSectionTypeELFSymbolTable;
case SHT_DYNSYM:
return eSectionTypeELFDynamicSymbols;
case SHT_RELA:
case SHT_REL:
return eSectionTypeELFRelocationEntries;
case SHT_DYNAMIC:
return eSectionTypeELFDynamicLinkInfo;
}
return GetSectionTypeFromName(H.section_name);
}
static Permissions GetPermissions(const ELFSectionHeader &H) {
Permissions Perm = Permissions(0);
if (H.sh_flags & SHF_ALLOC)
Perm |= ePermissionsReadable;
if (H.sh_flags & SHF_WRITE)
Perm |= ePermissionsWritable;
if (H.sh_flags & SHF_EXECINSTR)
Perm |= ePermissionsExecutable;
return Perm;
}
static Permissions GetPermissions(const ELFProgramHeader &H) {
Permissions Perm = Permissions(0);
if (H.p_flags & PF_R)
Perm |= ePermissionsReadable;
if (H.p_flags & PF_W)
Perm |= ePermissionsWritable;
if (H.p_flags & PF_X)
Perm |= ePermissionsExecutable;
return Perm;
}
namespace {
using VMRange = lldb_private::Range<addr_t, addr_t>;
struct SectionAddressInfo {
SectionSP Segment;
VMRange Range;
};
// (Unlinked) ELF object files usually have 0 for every section address, meaning
// we need to compute synthetic addresses in order for "file addresses" from
// different sections to not overlap. This class handles that logic.
class VMAddressProvider {
using VMMap = llvm::IntervalMap<addr_t, SectionSP, 4,
llvm::IntervalMapHalfOpenInfo<addr_t>>;
ObjectFile::Type ObjectType;
addr_t NextVMAddress = 0;
VMMap::Allocator Alloc;
VMMap Segments{Alloc};
VMMap Sections{Alloc};
lldb_private::Log *Log = GetLog(LLDBLog::Modules);
size_t SegmentCount = 0;
std::string SegmentName;
VMRange GetVMRange(const ELFSectionHeader &H) {
addr_t Address = H.sh_addr;
addr_t Size = H.sh_flags & SHF_ALLOC ? H.sh_size : 0;
// When this is a debug file for relocatable file, the address is all zero
// and thus needs to use accumulate method
if ((ObjectType == ObjectFile::Type::eTypeObjectFile ||
(ObjectType == ObjectFile::Type::eTypeDebugInfo && H.sh_addr == 0)) &&
Segments.empty() && (H.sh_flags & SHF_ALLOC)) {
NextVMAddress =
llvm::alignTo(NextVMAddress, std::max<addr_t>(H.sh_addralign, 1));
Address = NextVMAddress;
NextVMAddress += Size;
}
return VMRange(Address, Size);
}
public:
VMAddressProvider(ObjectFile::Type Type, llvm::StringRef SegmentName)
: ObjectType(Type), SegmentName(std::string(SegmentName)) {}
std::string GetNextSegmentName() const {
return llvm::formatv("{0}[{1}]", SegmentName, SegmentCount).str();
}
std::optional<VMRange> GetAddressInfo(const ELFProgramHeader &H) {
if (H.p_memsz == 0) {
LLDB_LOG(Log, "Ignoring zero-sized {0} segment. Corrupt object file?",
SegmentName);
return std::nullopt;
}
if (Segments.overlaps(H.p_vaddr, H.p_vaddr + H.p_memsz)) {
LLDB_LOG(Log, "Ignoring overlapping {0} segment. Corrupt object file?",
SegmentName);
return std::nullopt;
}
return VMRange(H.p_vaddr, H.p_memsz);
}
std::optional<SectionAddressInfo> GetAddressInfo(const ELFSectionHeader &H) {
VMRange Range = GetVMRange(H);
SectionSP Segment;
auto It = Segments.find(Range.GetRangeBase());
if ((H.sh_flags & SHF_ALLOC) && It.valid()) {
addr_t MaxSize;
if (It.start() <= Range.GetRangeBase()) {
MaxSize = It.stop() - Range.GetRangeBase();
Segment = *It;
} else
MaxSize = It.start() - Range.GetRangeBase();
if (Range.GetByteSize() > MaxSize) {
LLDB_LOG(Log, "Shortening section crossing segment boundaries. "
"Corrupt object file?");
Range.SetByteSize(MaxSize);
}
}
if (Range.GetByteSize() > 0 &&
Sections.overlaps(Range.GetRangeBase(), Range.GetRangeEnd())) {
LLDB_LOG(Log, "Ignoring overlapping section. Corrupt object file?");
return std::nullopt;
}
if (Segment)
Range.Slide(-Segment->GetFileAddress());
return SectionAddressInfo{Segment, Range};
}
void AddSegment(const VMRange &Range, SectionSP Seg) {
Segments.insert(Range.GetRangeBase(), Range.GetRangeEnd(), std::move(Seg));
++SegmentCount;
}
void AddSection(SectionAddressInfo Info, SectionSP Sect) {
if (Info.Range.GetByteSize() == 0)
return;
if (Info.Segment)
Info.Range.Slide(Info.Segment->GetFileAddress());
Sections.insert(Info.Range.GetRangeBase(), Info.Range.GetRangeEnd(),
std::move(Sect));
}
};
}
// We have to do this because ELF doesn't have section IDs, and also
// doesn't require section names to be unique. (We use the section index
// for section IDs, but that isn't guaranteed to be the same in separate
// debug images.)
static SectionSP FindMatchingSection(const SectionList &section_list,
SectionSP section) {
SectionSP sect_sp;
addr_t vm_addr = section->GetFileAddress();
llvm::StringRef name = section->GetName();
offset_t byte_size = section->GetByteSize();
bool thread_specific = section->IsThreadSpecific();
uint32_t permissions = section->GetPermissions();
uint32_t alignment = section->GetLog2Align();
for (auto sect : section_list) {
if (sect->GetName() == name &&
sect->IsThreadSpecific() == thread_specific &&
sect->GetPermissions() == permissions &&
sect->GetByteSize() == byte_size && sect->GetFileAddress() == vm_addr &&
sect->GetLog2Align() == alignment) {
sect_sp = sect;
break;
} else {
sect_sp = FindMatchingSection(sect->GetChildren(), section);
if (sect_sp)
break;
}
}
return sect_sp;
}
void ObjectFileELF::CreateSections(SectionList &unified_section_list) {
if (m_sections_up)
return;
m_sections_up = std::make_unique<SectionList>();
VMAddressProvider regular_provider(GetType(), "PT_LOAD");
VMAddressProvider tls_provider(GetType(), "PT_TLS");
for (const auto &EnumPHdr : llvm::enumerate(ProgramHeaders())) {
const ELFProgramHeader &PHdr = EnumPHdr.value();
if (PHdr.p_type != PT_LOAD && PHdr.p_type != PT_TLS)
continue;
VMAddressProvider &provider =
PHdr.p_type == PT_TLS ? tls_provider : regular_provider;
auto InfoOr = provider.GetAddressInfo(PHdr);
if (!InfoOr)
continue;
uint32_t Log2Align = llvm::Log2_64(std::max<elf_xword>(PHdr.p_align, 1));
SectionSP Segment = std::make_shared<Section>(
GetModule(), this, SegmentID(EnumPHdr.index()),
provider.GetNextSegmentName(), eSectionTypeContainer,
InfoOr->GetRangeBase(), InfoOr->GetByteSize(), PHdr.p_offset,
PHdr.p_filesz, Log2Align, /*flags*/ 0);
Segment->SetPermissions(GetPermissions(PHdr));
Segment->SetIsThreadSpecific(PHdr.p_type == PT_TLS);
m_sections_up->AddSection(Segment);
provider.AddSegment(*InfoOr, std::move(Segment));
}
ParseSectionHeaders();
if (m_section_headers.empty())
return;
for (SectionHeaderCollIter I = std::next(m_section_headers.begin());
I != m_section_headers.end(); ++I) {
const ELFSectionHeaderInfo &header = *I;
const std::string &name = I->section_name;
const uint64_t file_size =
header.sh_type == SHT_NOBITS ? 0 : header.sh_size;
VMAddressProvider &provider =
header.sh_flags & SHF_TLS ? tls_provider : regular_provider;
auto InfoOr = provider.GetAddressInfo(header);
if (!InfoOr)
continue;
SectionType sect_type = GetSectionType(header);
elf::elf_xword log2align =
(header.sh_addralign == 0) ? 0 : llvm::Log2_64(header.sh_addralign);
SectionSP section_sp = std::make_shared<Section>(
InfoOr->Segment, GetModule(), // Module to which this section belongs.
this, // ObjectFile to which this section belongs and should
// read section data from.
SectionIndex(I), // Section ID.
name, // Section name.
sect_type, // Section type.
InfoOr->Range.GetRangeBase(), // VM address.
InfoOr->Range.GetByteSize(), // VM size in bytes of this section.
header.sh_offset, // Offset of this section in the file.
file_size, // Size of the section as found in the file.
log2align, // Alignment of the section
header.sh_flags); // Flags for this section.
section_sp->SetPermissions(GetPermissions(header));
section_sp->SetIsThreadSpecific(header.sh_flags & SHF_TLS);
(InfoOr->Segment ? InfoOr->Segment->GetChildren() : *m_sections_up)
.AddSection(section_sp);
provider.AddSection(std::move(*InfoOr), std::move(section_sp));
}
// Merge the two adding any new sections, and overwriting any existing
// sections that are SHT_NOBITS
unified_section_list =
SectionList::Merge(unified_section_list, *m_sections_up, MergeSections);
// If there's a .gnu_debugdata section, we'll try to read the .symtab that's
// embedded in there and replace the one in the original object file (if any).
// If there's none in the orignal object file, we add it to it.
if (auto gdd_obj_file = GetGnuDebugDataObjectFile()) {
if (auto gdd_objfile_section_list = gdd_obj_file->GetSectionList()) {
if (SectionSP symtab_section_sp =
gdd_objfile_section_list->FindSectionByType(
eSectionTypeELFSymbolTable, true)) {
SectionSP module_section_sp = unified_section_list.FindSectionByType(
eSectionTypeELFSymbolTable, true);
if (module_section_sp)
unified_section_list.ReplaceSection(module_section_sp,
symtab_section_sp);
else
unified_section_list.AddSection(symtab_section_sp);
}
}
}
}
std::shared_ptr<ObjectFileELF> ObjectFileELF::GetGnuDebugDataObjectFile() {
if (m_gnu_debug_data_object_file != nullptr)
return m_gnu_debug_data_object_file;
SectionSP section = GetSectionList()->FindSectionByName(".gnu_debugdata");
if (!section)
return nullptr;
if (!llvm::compression::xz::isAvailable()) {
GetModule()->ReportWarning(
"no LZMA support found for reading .gnu_debugdata section");
return nullptr;
}
// Uncompress the data
DataExtractor data;
section->GetSectionData(data);
llvm::SmallVector<uint8_t, 0> uncompressedData;
auto err =
llvm::compression::xz::decompress(data.GetData(), uncompressedData);
if (err) {
GetModule()->ReportWarning(
"an error occurred while decompressing the section {0}: {1}",
section->GetName(), llvm::toString(std::move(err)).c_str());
return nullptr;
}
// Construct ObjectFileELF object from decompressed buffer
DataBufferSP gdd_data_buf(
new DataBufferHeap(uncompressedData.data(), uncompressedData.size()));
DataExtractorSP extractor_sp = std::make_shared<DataExtractor>(gdd_data_buf);
auto fspec = GetFileSpec().CopyByAppendingPathComponent(
llvm::StringRef("gnu_debugdata"));
m_gnu_debug_data_object_file.reset(new ObjectFileELF(
GetModule(), extractor_sp, 0, &fspec, 0, gdd_data_buf->GetByteSize()));
// This line is essential; otherwise a breakpoint can be set but not hit.
m_gnu_debug_data_object_file->SetType(ObjectFile::eTypeDebugInfo);
ArchSpec spec = m_gnu_debug_data_object_file->GetArchitecture();
if (spec && m_gnu_debug_data_object_file->SetModulesArchitecture(spec))
return m_gnu_debug_data_object_file;
return nullptr;
}
// Find the arm/aarch64 mapping symbol character in the given symbol name.
// Mapping symbols have the form of "$<char>[.<any>]*". Additionally we
// recognize cases when the mapping symbol prefixed by an arbitrary string
// because if a symbol prefix added to each symbol in the object file with
// objcopy then the mapping symbols are also prefixed.
static char FindArmAarch64MappingSymbol(llvm::StringRef symbol_name) {
size_t dollar_pos = symbol_name.find('$');
if (dollar_pos == llvm::StringRef::npos)
return '\0';
llvm::StringRef mapping = symbol_name.drop_front(dollar_pos + 1);
if (mapping.empty())
return '\0';
if (mapping.size() == 1 || mapping[1] == '.')
return mapping[0];
return '\0';
}
static char FindRISCVMappingSymbol(llvm::StringRef symbol_name) {
if (symbol_name == "$d")
return 'd';
if (symbol_name == "$x")
return 'x';
return '\0';
}
#define STO_MIPS_ISA (3 << 6)
#define STO_MICROMIPS (2 << 6)
#define IS_MICROMIPS(ST_OTHER) (((ST_OTHER)&STO_MIPS_ISA) == STO_MICROMIPS)
// private
std::pair<unsigned, ObjectFileELF::FileAddressToAddressClassMap>
ObjectFileELF::ParseSymbols(Symtab *symtab, user_id_t start_id,
SectionList *section_list, const size_t num_symbols,
const DataExtractor &symtab_data,
const DataExtractor &strtab_data) {
ELFSymbol symbol;
lldb::offset_t offset = 0;
// The changes these symbols would make to the class map. We will also update
// m_address_class_map but need to tell the caller what changed because the
// caller may be another object file.
FileAddressToAddressClassMap address_class_map;
static constexpr llvm::StringLiteral text_section_name(".text");
static constexpr llvm::StringLiteral init_section_name(".init");
static constexpr llvm::StringLiteral fini_section_name(".fini");
static constexpr llvm::StringLiteral ctors_section_name(".ctors");
static constexpr llvm::StringLiteral dtors_section_name(".dtors");
static constexpr llvm::StringLiteral data_section_name(".data");
static constexpr llvm::StringLiteral rodata_section_name(".rodata");
static constexpr llvm::StringLiteral rodata1_section_name(".rodata1");
static constexpr llvm::StringLiteral data2_section_name(".data1");
static constexpr llvm::StringLiteral bss_section_name(".bss");
// On Android the oatdata and the oatexec symbols in the oat and odex files
// covers the full .text section what causes issues with displaying unusable
// symbol name to the user and very slow unwinding speed because the
// instruction emulation based unwind plans try to emulate all instructions
// in these symbols. Don't add these symbols to the symbol list as they have
// no use for the debugger and they are causing a lot of trouble. Filtering
// can't be restricted to Android because this special object file don't
// contain the note section specifying the environment to Android but the
// custom extension and file name makes it highly unlikely that this will
// collide with anything else.
llvm::StringRef file_extension = m_file.GetFileNameExtension();
bool skip_oatdata_oatexec =
file_extension == ".oat" || file_extension == ".odex";
ArchSpec arch = GetArchitecture();
ModuleSP module_sp(GetModule());
SectionList *module_section_list =
module_sp ? module_sp->GetSectionList() : nullptr;
// We might have debug information in a separate object, in which case
// we need to map the sections from that object to the sections in the
// main object during symbol lookup. If we had to compare the sections
// for every single symbol, that would be expensive, so this map is
// used to accelerate the process.
std::unordered_map<lldb::SectionSP, lldb::SectionSP> section_map;
unsigned i;
for (i = 0; i < num_symbols; ++i) {
if (!symbol.Parse(symtab_data, &offset))
break;
// A missing or unterminated name reads as empty.
llvm::StringRef symbol_name =
strtab_data.PeekCStr(symbol.st_name).value_or("");
// Skip local symbols starting with ".L" because these are compiler
// generated local labels used for internal purposes (e.g. debugging,
// optimization) and are not relevant for symbol resolution or external
// linkage.
if (symbol_name.starts_with(".L"))
continue;
// The mold linker emits an extra function symbol like "foo$plt" in
// .symtab/.dynsym that overlaps the PLT stub which ParsePLTRelocations
// will synthesize as an eSymbolTypeTrampoline named "foo". Drop the
// redundant sibling here so the finalized symbol table has a single
// clean entry per PLT function.
if (symbol.getType() == STT_FUNC && symbol_name.ends_with("$plt"))
continue;
// No need to add non-section symbols that have no names
if (symbol.getType() != STT_SECTION && symbol_name.empty())
continue;
// Skipping oatdata and oatexec sections if it is requested. See details
// above the definition of skip_oatdata_oatexec for the reasons.
if (skip_oatdata_oatexec &&
(symbol_name == "oatdata" || symbol_name == "oatexec"))
continue;
SectionSP symbol_section_sp;
SymbolType symbol_type = eSymbolTypeInvalid;
Elf64_Half shndx = symbol.st_shndx;
switch (shndx) {
case SHN_ABS:
symbol_type = eSymbolTypeAbsolute;
break;
case SHN_UNDEF:
symbol_type = eSymbolTypeUndefined;
break;
default:
symbol_section_sp = section_list->FindSectionByID(shndx);
break;
}
// If a symbol is undefined do not process it further even if it has a STT
// type
if (symbol_type != eSymbolTypeUndefined) {
switch (symbol.getType()) {
default:
case STT_NOTYPE:
// The symbol's type is not specified.
break;
case STT_OBJECT:
// The symbol is associated with a data object, such as a variable, an
// array, etc.
symbol_type = eSymbolTypeData;
break;
case STT_FUNC:
// The symbol is associated with a function or other executable code.
symbol_type = eSymbolTypeCode;
break;
case STT_SECTION:
// The symbol is associated with a section. Symbol table entries of
// this type exist primarily for relocation and normally have STB_LOCAL
// binding.
break;
case STT_FILE:
// Conventionally, the symbol's name gives the name of the source file
// associated with the object file. A file symbol has STB_LOCAL
// binding, its section index is SHN_ABS, and it precedes the other
// STB_LOCAL symbols for the file, if it is present.
symbol_type = eSymbolTypeSourceFile;
break;
case STT_GNU_IFUNC:
// The symbol is associated with an indirect function. The actual
// function will be resolved if it is referenced.
symbol_type = eSymbolTypeResolver;
break;
case STT_TLS:
// The symbol is associated with a thread-local data object, such as
// a thread-local variable.
symbol_type = eSymbolTypeData;
break;
}
}
if (symbol_type == eSymbolTypeInvalid && symbol.getType() != STT_SECTION) {
if (symbol_section_sp) {
llvm::StringRef sect_name = symbol_section_sp->GetName();
if (sect_name == text_section_name || sect_name == init_section_name ||
sect_name == fini_section_name || sect_name == ctors_section_name ||
sect_name == dtors_section_name) {
symbol_type = eSymbolTypeCode;
} else if (sect_name == data_section_name ||
sect_name == data2_section_name ||
sect_name == rodata_section_name ||
sect_name == rodata1_section_name ||
sect_name == bss_section_name) {
symbol_type = eSymbolTypeData;
} else if (symbol_section_sp->Get() & SHF_ALLOC)
// Check for symbols from custom sections (e.g. added by linker
// scripts) with SHF_ALLOC (i.e. occupies memory during process
// execution) in their flags.
symbol_type = eSymbolTypeData;
}
}
int64_t symbol_value_offset = 0;
uint32_t additional_flags = 0;
if (arch.IsValid()) {
if (arch.GetMachine() == llvm::Triple::arm) {
if (symbol.getBinding() == STB_LOCAL) {
char mapping_symbol = FindArmAarch64MappingSymbol(symbol_name);
if (symbol_type == eSymbolTypeCode) {
switch (mapping_symbol) {
case 'a':
// $a[.<any>]* - marks an ARM instruction sequence
address_class_map[symbol.st_value] = AddressClass::eCode;
break;
case 'b':
case 't':
// $b[.<any>]* - marks a THUMB BL instruction sequence
// $t[.<any>]* - marks a THUMB instruction sequence
address_class_map[symbol.st_value] =
AddressClass::eCodeAlternateISA;
break;
case 'd':
// $d[.<any>]* - marks a data item sequence (e.g. lit pool)
address_class_map[symbol.st_value] = AddressClass::eData;
break;
}
}
if (mapping_symbol)
continue;
}
} else if (arch.GetMachine() == llvm::Triple::aarch64) {
if (symbol.getBinding() == STB_LOCAL) {
char mapping_symbol = FindArmAarch64MappingSymbol(symbol_name);
if (symbol_type == eSymbolTypeCode) {
switch (mapping_symbol) {
case 'x':
// $x[.<any>]* - marks an A64 instruction sequence
address_class_map[symbol.st_value] = AddressClass::eCode;
break;
case 'd':
// $d[.<any>]* - marks a data item sequence (e.g. lit pool)
address_class_map[symbol.st_value] = AddressClass::eData;
break;
}
}
if (mapping_symbol)
continue;
}
} else if (arch.GetTriple().isRISCV()) {
if (symbol.getBinding() == STB_LOCAL) {
char mapping_symbol = FindRISCVMappingSymbol(symbol_name);
if (symbol_type == eSymbolTypeCode) {
// Only handle $d and $x mapping symbols.
// Other mapping symbols are ignored as they don't affect address
// classification.
switch (mapping_symbol) {
case 'x':
// $x - marks a RISCV instruction sequence
address_class_map[symbol.st_value] = AddressClass::eCode;
break;
case 'd':
// $d - marks a RISCV data item sequence
address_class_map[symbol.st_value] = AddressClass::eData;
break;
}
}
if (mapping_symbol)
continue;
}
}
if (arch.GetMachine() == llvm::Triple::arm) {
if (symbol_type == eSymbolTypeCode) {
if (symbol.st_value & 1) {
// Subtracting 1 from the address effectively unsets the low order
// bit, which results in the address actually pointing to the
// beginning of the symbol. This delta will be used below in
// conjunction with symbol.st_value to produce the final
// symbol_value that we store in the symtab.
symbol_value_offset = -1;
address_class_map[symbol.st_value ^ 1] =
AddressClass::eCodeAlternateISA;
} else {
// This address is ARM
address_class_map[symbol.st_value] = AddressClass::eCode;
}
}
}
/*
* MIPS:
* The bit #0 of an address is used for ISA mode (1 for microMIPS, 0 for
* MIPS).
* This allows processor to switch between microMIPS and MIPS without any
* need
* for special mode-control register. However, apart from .debug_line,
* none of
* the ELF/DWARF sections set the ISA bit (for symbol or section). Use
* st_other
* flag to check whether the symbol is microMIPS and then set the address
* class
* accordingly.
*/
if (arch.IsMIPS()) {
if (IS_MICROMIPS(symbol.st_other))
address_class_map[symbol.st_value] = AddressClass::eCodeAlternateISA;
else if ((symbol.st_value & 1) && (symbol_type == eSymbolTypeCode)) {
symbol.st_value = symbol.st_value & (~1ull);
address_class_map[symbol.st_value] = AddressClass::eCodeAlternateISA;
} else {
if (symbol_type == eSymbolTypeCode)
address_class_map[symbol.st_value] = AddressClass::eCode;
else if (symbol_type == eSymbolTypeData)
address_class_map[symbol.st_value] = AddressClass::eData;
else
address_class_map[symbol.st_value] = AddressClass::eUnknown;
}
}
}
// symbol_value_offset may contain 0 for ARM symbols or -1 for THUMB
// symbols. See above for more details.
uint64_t symbol_value = symbol.st_value + symbol_value_offset;
if (symbol_section_sp &&
CalculateType() != ObjectFile::Type::eTypeObjectFile)
symbol_value -= symbol_section_sp->GetFileAddress();
if (symbol_section_sp && module_section_list &&
module_section_list != section_list) {
auto section_it = section_map.find(symbol_section_sp);
if (section_it == section_map.end()) {
section_it = section_map
.emplace(symbol_section_sp,
FindMatchingSection(*module_section_list,
symbol_section_sp))
.first;
}
if (section_it->second)
symbol_section_sp = section_it->second;
}
bool is_global = symbol.getBinding() == STB_GLOBAL;
uint32_t flags = symbol.st_other << 8 | symbol.st_info | additional_flags;
// Symbol names may contain @VERSION suffixes. Find those and strip them
// temporarily.
size_t version_pos = symbol_name.find('@');
bool has_suffix = version_pos != llvm::StringRef::npos;
llvm::StringRef symbol_bare = symbol_name.substr(0, version_pos);
Mangled mangled(symbol_bare);
// Now append the suffix back to mangled and unmangled names. Only do it if
// the demangling was successful (string is not empty).
if (has_suffix) {
llvm::StringRef suffix = symbol_name.substr(version_pos);
llvm::StringRef mangled_name = mangled.GetMangledName().GetStringRef();
if (!mangled_name.empty())
mangled.SetMangledName(ConstString((mangled_name + suffix).str()));
ConstString demangled = mangled.GetDemangledName();
llvm::StringRef demangled_name = demangled.GetStringRef();
if (!demangled_name.empty())
mangled.SetDemangledName(ConstString((demangled_name + suffix).str()));
}
// In ELF all symbol should have a valid size but it is not true for some
// function symbols coming from hand written assembly. As none of the
// function symbol should have 0 size we try to calculate the size for
// these symbols in the symtab with saying that their original size is not
// valid.
bool symbol_size_valid =
symbol.st_size != 0 || symbol.getType() != STT_FUNC;
bool is_trampoline = false;
if (arch.IsValid() && (arch.GetMachine() == llvm::Triple::aarch64)) {
// On AArch64, trampolines are registered as code.
// If we detect a trampoline (which starts with __AArch64ADRPThunk_ or
// __AArch64AbsLongThunk_) we register the symbol as a trampoline. This
// way we will be able to detect the trampoline when we step in a function
// and step through the trampoline.
if (symbol_type == eSymbolTypeCode) {
llvm::StringRef trampoline_name = mangled.GetName().GetStringRef();
if (trampoline_name.starts_with("__AArch64ADRPThunk_") ||
trampoline_name.starts_with("__AArch64AbsLongThunk_")) {
symbol_type = eSymbolTypeTrampoline;
is_trampoline = true;
}
}
}
Symbol dc_symbol(
i + start_id, // ID is the original symbol table index.
mangled,
symbol_type, // Type of this symbol
is_global, // Is this globally visible?
false, // Is this symbol debug info?
is_trampoline, // Is this symbol a trampoline?
false, // Is this symbol artificial?
AddressRange(symbol_section_sp, // Section in which this symbol is
// defined or null.
symbol_value, // Offset in section or symbol value.
symbol.st_size), // Size in bytes of this symbol.
symbol_size_valid, // Symbol size is valid
has_suffix, // Contains linker annotations?
flags); // Symbol flags.
if (symbol.getBinding() == STB_WEAK)
dc_symbol.SetIsWeak(true);
symtab->AddSymbol(dc_symbol);
}
m_address_class_map.merge(address_class_map);
return {i, address_class_map};
}
std::pair<unsigned, ObjectFileELF::FileAddressToAddressClassMap>
ObjectFileELF::ParseSymbolTable(Symtab *symbol_table, user_id_t start_id,
lldb_private::Section *symtab) {
if (symtab->GetObjectFile() != this) {
// If the symbol table section is owned by a different object file, have it
// do the parsing.
ObjectFileELF *obj_file_elf =
static_cast<ObjectFileELF *>(symtab->GetObjectFile());
auto [num_symbols, address_class_map] =
obj_file_elf->ParseSymbolTable(symbol_table, start_id, symtab);
// The other object file returned the changes it made to its address
// class map, make the same changes to ours.
m_address_class_map.merge(address_class_map);
return {num_symbols, address_class_map};
}
// Get section list for this object file.
SectionList *section_list = m_sections_up.get();
if (!section_list)
return {};
user_id_t symtab_id = symtab->GetID();
const ELFSectionHeaderInfo *symtab_hdr = GetSectionHeaderByIndex(symtab_id);
assert(symtab_hdr->sh_type == SHT_SYMTAB ||
symtab_hdr->sh_type == SHT_DYNSYM);
// sh_link: section header index of associated string table.
user_id_t strtab_id = symtab_hdr->sh_link;
Section *strtab = section_list->FindSectionByID(strtab_id).get();
if (symtab && strtab) {
assert(symtab->GetObjectFile() == this);
assert(strtab->GetObjectFile() == this);
DataExtractor symtab_data;
DataExtractor strtab_data;
if (ReadSectionData(symtab, symtab_data) &&
ReadSectionData(strtab, strtab_data)) {
size_t num_symbols = symtab_data.GetByteSize() / symtab_hdr->sh_entsize;
return ParseSymbols(symbol_table, start_id, section_list, num_symbols,
symtab_data, strtab_data);
}
}
return {0, {}};
}
size_t ObjectFileELF::ParseDynamicSymbols() {
if (m_dynamic_symbols.size())
return m_dynamic_symbols.size();
std::optional<DataExtractor> dynamic_data = GetDynamicData();
if (!dynamic_data)
return 0;
ELFDynamicWithName e;
lldb::offset_t cursor = 0;
while (e.symbol.Parse(*dynamic_data, &cursor)) {
m_dynamic_symbols.push_back(e);
if (e.symbol.d_tag == DT_NULL)
break;
}
if (std::optional<DataExtractor> dynstr_data = GetDynstrData()) {
for (ELFDynamicWithName &entry : m_dynamic_symbols) {
switch (entry.symbol.d_tag) {
case DT_NEEDED:
case DT_SONAME:
case DT_RPATH:
case DT_RUNPATH:
case DT_AUXILIARY:
case DT_FILTER: {
lldb::offset_t cursor = entry.symbol.d_val;
const char *name = dynstr_data->GetCStr(&cursor);
if (name)
entry.name = std::string(name);
break;
}
default:
break;
}
}
}
return m_dynamic_symbols.size();
}
const ELFDynamic *ObjectFileELF::FindDynamicSymbol(unsigned tag) {
if (!ParseDynamicSymbols())
return nullptr;
for (const auto &entry : m_dynamic_symbols) {
if (entry.symbol.d_tag == tag)
return &entry.symbol;
}
return nullptr;
}
unsigned ObjectFileELF::PLTRelocationType() {
// DT_PLTREL
// This member specifies the type of relocation entry to which the
// procedure linkage table refers. The d_val member holds DT_REL or
// DT_RELA, as appropriate. All relocations in a procedure linkage table
// must use the same relocation.
const ELFDynamic *symbol = FindDynamicSymbol(DT_PLTREL);
if (symbol)
return symbol->d_val;
return 0;
}
// Returns the size of the normal plt entries and the offset of the first
// normal plt entry. The 0th entry in the plt table is usually a resolution
// entry which have different size in some architectures then the rest of the
// plt entries.
static std::pair<uint64_t, uint64_t>
GetPltEntrySizeAndOffset(const ELFSectionHeader *rel_hdr,
const ELFSectionHeader *plt_hdr) {
const elf_xword num_relocations = rel_hdr->sh_size / rel_hdr->sh_entsize;
// Clang 3.3 sets entsize to 4 for 32-bit binaries, but the plt entries are
// 16 bytes. So round the entsize up by the alignment if addralign is set.
elf_xword plt_entsize =
plt_hdr->sh_addralign
? llvm::alignTo(plt_hdr->sh_entsize, plt_hdr->sh_addralign)
: plt_hdr->sh_entsize;
// Some linkers e.g ld for arm, fill plt_hdr->sh_entsize field incorrectly.
// PLT entries relocation code in general requires multiple instruction and
// should be greater than 4 bytes in most cases. Try to guess correct size
// just in case.
if (plt_entsize <= 4) {
// The linker haven't set the plt_hdr->sh_entsize field. Try to guess the
// size of the plt entries based on the number of entries and the size of
// the plt section with the assumption that the size of the 0th entry is at
// least as big as the size of the normal entries and it isn't much bigger
// then that.
if (plt_hdr->sh_addralign)
plt_entsize = plt_hdr->sh_size / plt_hdr->sh_addralign /
(num_relocations + 1) * plt_hdr->sh_addralign;
else
plt_entsize = plt_hdr->sh_size / (num_relocations + 1);
}
elf_xword plt_offset = plt_hdr->sh_size - num_relocations * plt_entsize;
return std::make_pair(plt_entsize, plt_offset);
}
static unsigned ParsePLTRelocations(
Symtab *symbol_table, user_id_t start_id, unsigned rel_type,
const ELFHeader *hdr, const ELFSectionHeader *rel_hdr,
const ELFSectionHeader *plt_hdr, const ELFSectionHeader *sym_hdr,
const lldb::SectionSP &plt_section_sp, DataExtractor &rel_data,
DataExtractor &symtab_data, DataExtractor &strtab_data) {
ELFRelocation rel(rel_type);
ELFSymbol symbol;
lldb::offset_t offset = 0;
uint64_t plt_offset, plt_entsize;
std::tie(plt_entsize, plt_offset) =
GetPltEntrySizeAndOffset(rel_hdr, plt_hdr);
const elf_xword num_relocations = rel_hdr->sh_size / rel_hdr->sh_entsize;
typedef unsigned (*reloc_info_fn)(const ELFRelocation &rel);
reloc_info_fn reloc_type;
reloc_info_fn reloc_symbol;
if (hdr->Is32Bit()) {
reloc_type = ELFRelocation::RelocType32;
reloc_symbol = ELFRelocation::RelocSymbol32;
} else {
reloc_type = ELFRelocation::RelocType64;
reloc_symbol = ELFRelocation::RelocSymbol64;
}
unsigned slot_type = hdr->GetRelocationJumpSlotType();
unsigned i;
for (i = 0; i < num_relocations; ++i) {
if (!rel.Parse(rel_data, &offset))
break;
if (reloc_type(rel) != slot_type)
continue;
lldb::offset_t symbol_offset = reloc_symbol(rel) * sym_hdr->sh_entsize;
if (!symbol.Parse(symtab_data, &symbol_offset))
break;
llvm::StringRef symbol_name =
strtab_data.PeekCStr(symbol.st_name).value_or("");
uint64_t plt_index = plt_offset + i * plt_entsize;
Symbol jump_symbol(
i + start_id, // Symbol table index
symbol_name, // symbol name.
eSymbolTypeTrampoline, // Type of this symbol
false, // Is this globally visible?
false, // Is this symbol debug info?
true, // Is this symbol a trampoline?
true, // Is this symbol artificial?
plt_section_sp, // Section in which this symbol is defined or null.
plt_index, // Offset in section or symbol value.
plt_entsize, // Size in bytes of this symbol.
true, // Size is valid
false, // Contains linker annotations?
0); // Symbol flags.
symbol_table->AddSymbol(jump_symbol);
}
return i;
}
unsigned
ObjectFileELF::ParseTrampolineSymbols(Symtab *symbol_table, user_id_t start_id,
const ELFSectionHeaderInfo *rel_hdr,
user_id_t rel_id) {
assert(rel_hdr->sh_type == SHT_RELA || rel_hdr->sh_type == SHT_REL);
// The link field points to the associated symbol table.
user_id_t symtab_id = rel_hdr->sh_link;
// If the link field doesn't point to the appropriate symbol name table then
// try to find it by name as some compiler don't fill in the link fields.
if (!symtab_id)
symtab_id = GetSectionIndexByName(".dynsym");
// Get PLT section. We cannot use rel_hdr->sh_info, since current linkers
// point that to the .got.plt or .got section instead of .plt.
user_id_t plt_id = GetSectionIndexByName(".plt");
if (!symtab_id || !plt_id)
return 0;
const ELFSectionHeaderInfo *plt_hdr = GetSectionHeaderByIndex(plt_id);
if (!plt_hdr)
return 0;
const ELFSectionHeaderInfo *sym_hdr = GetSectionHeaderByIndex(symtab_id);
if (!sym_hdr)
return 0;
SectionList *section_list = m_sections_up.get();
if (!section_list)
return 0;
Section *rel_section = section_list->FindSectionByID(rel_id).get();
if (!rel_section)
return 0;
SectionSP plt_section_sp(section_list->FindSectionByID(plt_id));
if (!plt_section_sp)
return 0;
Section *symtab = section_list->FindSectionByID(symtab_id).get();
if (!symtab)
return 0;
// sh_link points to associated string table.
Section *strtab = section_list->FindSectionByID(sym_hdr->sh_link).get();
if (!strtab)
return 0;
DataExtractor rel_data;
if (!ReadSectionData(rel_section, rel_data))
return 0;
DataExtractor symtab_data;
if (!ReadSectionData(symtab, symtab_data))
return 0;
DataExtractor strtab_data;
if (!ReadSectionData(strtab, strtab_data))
return 0;
unsigned rel_type = PLTRelocationType();
if (!rel_type)
return 0;
return ParsePLTRelocations(symbol_table, start_id, rel_type, &m_header,
rel_hdr, plt_hdr, sym_hdr, plt_section_sp,
rel_data, symtab_data, strtab_data);
}
/// Returns the \p size bytes at \p offset in \p debug_data for a relocation to
/// patch, or reports an error and returns null if they overrun the section.
static uint8_t *GetRelocationTarget(DataExtractor &debug_data,
Section *rel_section, uint64_t offset,
size_t size) {
if (!debug_data.ValidOffsetForDataOfSize(offset, size)) {
rel_section->GetModule()->ReportError("relocation outside of section {0}",
rel_section->GetName());
return nullptr;
}
DataBufferSP data_buffer_sp = debug_data.GetSharedDataBuffer();
// ObjectFileELF creates a WritableDataBuffer in CreateInstance.
WritableDataBuffer *data_buffer =
llvm::cast<WritableDataBuffer>(data_buffer_sp.get());
return data_buffer->GetBytes() + debug_data.GetSharedDataOffset() + offset;
}
static void ApplyELF64ABS64Relocation(Symtab *symtab, ELFRelocation &rel,
DataExtractor &debug_data,
Section *rel_section) {
const Symbol *symbol =
symtab->FindSymbolByID(ELFRelocation::RelocSymbol64(rel));
if (symbol) {
addr_t value = symbol->GetAddressRef().GetFileAddress();
uint8_t *dst = GetRelocationTarget(debug_data, rel_section,
ELFRelocation::RelocOffset64(rel),
sizeof(uint64_t));
if (!dst)
return;
uint64_t val_offset = value + ELFRelocation::RelocAddend64(rel);
memcpy(dst, &val_offset, sizeof(uint64_t));
}
}
static void ApplyELF64ABS32Relocation(Symtab *symtab, ELFRelocation &rel,
DataExtractor &debug_data,
Section *rel_section, bool is_signed) {
const Symbol *symbol =
symtab->FindSymbolByID(ELFRelocation::RelocSymbol64(rel));
if (symbol) {
addr_t value = symbol->GetAddressRef().GetFileAddress();
value += ELFRelocation::RelocAddend32(rel);
if ((!is_signed && (value > UINT32_MAX)) ||
(is_signed &&
((int64_t)value > INT32_MAX || (int64_t)value < INT32_MIN))) {
Log *log = GetLog(LLDBLog::Modules);
LLDB_LOGF(log, "Failed to apply debug info relocations");
return;
}
uint32_t truncated_addr = (value & 0xFFFFFFFF);
uint8_t *dst = GetRelocationTarget(debug_data, rel_section,
ELFRelocation::RelocOffset32(rel),
sizeof(uint32_t));
if (!dst)
return;
memcpy(dst, &truncated_addr, sizeof(uint32_t));
}
}
static void ApplyELF32ABS32RelRelocation(Symtab *symtab, ELFRelocation &rel,
DataExtractor &debug_data,
Section *rel_section) {
Log *log = GetLog(LLDBLog::Modules);
const Symbol *symbol =
symtab->FindSymbolByID(ELFRelocation::RelocSymbol32(rel));
if (symbol) {
addr_t value = symbol->GetAddressRef().GetFileAddress();
if (value == LLDB_INVALID_ADDRESS) {
const char *name = symbol->GetName().GetCString();
LLDB_LOGF(log, "Debug info symbol invalid: %s", name);
return;
}
assert(llvm::isUInt<32>(value) && "Valid addresses are 32-bit");
uint8_t *dst = GetRelocationTarget(debug_data, rel_section,
ELFRelocation::RelocOffset32(rel),
sizeof(uint32_t));
if (!dst)
return;
// Implicit addend is stored inline as a signed value.
int32_t addend;
memcpy(&addend, dst, sizeof(int32_t));
// The sum must be positive. This extra check prevents UB from overflow in
// the actual range check below.
if (addend < 0 && static_cast<uint32_t>(-addend) > value) {
LLDB_LOGF(log, "Debug info relocation overflow: 0x%" PRIx64,
static_cast<int64_t>(value) + addend);
return;
}
if (!llvm::isUInt<32>(value + addend)) {
LLDB_LOGF(log, "Debug info relocation out of range: 0x%" PRIx64, value);
return;
}
uint32_t addr = value + addend;
memcpy(dst, &addr, sizeof(uint32_t));
}
}
unsigned ObjectFileELF::ApplyRelocations(
Symtab *symtab, const ELFHeader *hdr, const ELFSectionHeader *rel_hdr,
const ELFSectionHeader *symtab_hdr, const ELFSectionHeader *debug_hdr,
DataExtractor &rel_data, DataExtractor &symtab_data,
DataExtractor &debug_data, Section *rel_section) {
ELFRelocation rel(rel_hdr->sh_type);
lldb::addr_t offset = 0;
const unsigned num_relocations = rel_hdr->sh_size / rel_hdr->sh_entsize;
typedef unsigned (*reloc_info_fn)(const ELFRelocation &rel);
reloc_info_fn reloc_type;
reloc_info_fn reloc_symbol;
if (hdr->Is32Bit()) {
reloc_type = ELFRelocation::RelocType32;
reloc_symbol = ELFRelocation::RelocSymbol32;
} else {
reloc_type = ELFRelocation::RelocType64;
reloc_symbol = ELFRelocation::RelocSymbol64;
}
for (unsigned i = 0; i < num_relocations; ++i) {
if (!rel.Parse(rel_data, &offset)) {
GetModule()->ReportError(".rel{0}[{1:d}] failed to parse relocation",
rel_section->GetName(), i);
break;
}
const Symbol *symbol = nullptr;
if (hdr->Is32Bit()) {
switch (hdr->e_machine) {
case llvm::ELF::EM_ARM:
switch (reloc_type(rel)) {
case R_ARM_ABS32:
ApplyELF32ABS32RelRelocation(symtab, rel, debug_data, rel_section);
break;
case R_ARM_REL32:
GetModule()->ReportError("unsupported AArch32 relocation:"
" .rel{0}[{1}], type {2}",
rel_section->GetName(), i, reloc_type(rel));
break;
default:
assert(false && "unexpected relocation type");
}
break;
case llvm::ELF::EM_386:
switch (reloc_type(rel)) {
case R_386_32:
symbol = symtab->FindSymbolByID(reloc_symbol(rel));
if (symbol) {
uint32_t *dst = reinterpret_cast<uint32_t *>(GetRelocationTarget(
debug_data, rel_section, ELFRelocation::RelocOffset32(rel),
sizeof(uint32_t)));
if (!dst)
break;
addr_t value = symbol->GetAddressRef().GetFileAddress();
if (rel.IsRela()) {
value += ELFRelocation::RelocAddend32(rel);
} else {
value += *dst;
}
*dst = value;
} else {
GetModule()->ReportError(".rel{0}[{1}] unknown symbol id: {2:d}",
rel_section->GetName(), i,
reloc_symbol(rel));
}
break;
case R_386_NONE:
case R_386_PC32:
GetModule()->ReportError("unsupported i386 relocation:"
" .rel{0}[{1}], type {2}",
rel_section->GetName(), i, reloc_type(rel));
break;
default:
assert(false && "unexpected relocation type");
break;
}
break;
default:
GetModule()->ReportError("unsupported 32-bit ELF machine arch: {0}", hdr->e_machine);
break;
}
} else {
switch (hdr->e_machine) {
case llvm::ELF::EM_AARCH64:
switch (reloc_type(rel)) {
case R_AARCH64_ABS64:
ApplyELF64ABS64Relocation(symtab, rel, debug_data, rel_section);
break;
case R_AARCH64_ABS32:
ApplyELF64ABS32Relocation(symtab, rel, debug_data, rel_section, true);
break;
default:
assert(false && "unexpected relocation type");
}
break;
case llvm::ELF::EM_LOONGARCH:
switch (reloc_type(rel)) {
case R_LARCH_64:
ApplyELF64ABS64Relocation(symtab, rel, debug_data, rel_section);
break;
case R_LARCH_32:
ApplyELF64ABS32Relocation(symtab, rel, debug_data, rel_section, true);
break;
default:
assert(false && "unexpected relocation type");
}
break;
case llvm::ELF::EM_X86_64:
switch (reloc_type(rel)) {
case R_X86_64_64:
ApplyELF64ABS64Relocation(symtab, rel, debug_data, rel_section);
break;
case R_X86_64_32:
ApplyELF64ABS32Relocation(symtab, rel, debug_data, rel_section,
false);
break;
case R_X86_64_32S:
ApplyELF64ABS32Relocation(symtab, rel, debug_data, rel_section, true);
break;
case R_X86_64_PC32:
default:
assert(false && "unexpected relocation type");
}
break;
default:
GetModule()->ReportError("unsupported 64-bit ELF machine arch: {0}", hdr->e_machine);
break;
}
}
}
return 0;
}
unsigned ObjectFileELF::RelocateDebugSections(const ELFSectionHeader *rel_hdr,
user_id_t rel_id,
lldb_private::Symtab *thetab) {
assert(rel_hdr->sh_type == SHT_RELA || rel_hdr->sh_type == SHT_REL);
// Parse in the section list if needed.
SectionList *section_list = GetSectionList();
if (!section_list)
return 0;
user_id_t symtab_id = rel_hdr->sh_link;
user_id_t debug_id = rel_hdr->sh_info;
const ELFSectionHeader *symtab_hdr = GetSectionHeaderByIndex(symtab_id);
if (!symtab_hdr)
return 0;
const ELFSectionHeader *debug_hdr = GetSectionHeaderByIndex(debug_id);
if (!debug_hdr)
return 0;
Section *rel = section_list->FindSectionByID(rel_id).get();
if (!rel)
return 0;
Section *symtab = section_list->FindSectionByID(symtab_id).get();
if (!symtab)
return 0;
Section *debug = section_list->FindSectionByID(debug_id).get();
if (!debug)
return 0;
DataExtractorSP rel_data_sp = std::make_shared<DataExtractor>();
DataExtractorSP symtab_data_sp = std::make_shared<DataExtractor>();
DataExtractorSP debug_data_sp = std::make_shared<DataExtractor>();
if (GetData(rel->GetFileOffset(), rel->GetFileSize(), rel_data_sp) &&
GetData(symtab->GetFileOffset(), symtab->GetFileSize(), symtab_data_sp) &&
GetData(debug->GetFileOffset(), debug->GetFileSize(), debug_data_sp)) {
ApplyRelocations(thetab, &m_header, rel_hdr, symtab_hdr, debug_hdr,
*rel_data_sp, *symtab_data_sp, *debug_data_sp, debug);
}
return 0;
}
void ObjectFileELF::ParseSymtab(Symtab &lldb_symtab) {
ModuleSP module_sp(GetModule());
if (!module_sp)
return;
Progress progress("Parsing symbol table",
m_file.GetFilename().nonEmptyOr("<Unknown>").str());
ElapsedTime elapsed(module_sp->GetSymtabParseTime());
// We always want to use the main object file so we (hopefully) only have one
// cached copy of our symtab, dynamic sections, etc.
ObjectFile *module_obj_file = module_sp->GetObjectFile();
if (module_obj_file && module_obj_file != this)
return module_obj_file->ParseSymtab(lldb_symtab);
SectionList *section_list = module_sp->GetSectionList();
if (!section_list)
return;
uint64_t symbol_id = 0;
// Sharable objects and dynamic executables usually have 2 distinct symbol
// tables, one named ".symtab", and the other ".dynsym". The dynsym is a
// smaller version of the symtab that only contains global symbols. The
// information found in the dynsym is therefore also found in the symtab,
// while the reverse is not necessarily true.
Section *symtab =
section_list->FindSectionByType(eSectionTypeELFSymbolTable, true).get();
if (symtab) {
auto [num_symbols, address_class_map] =
ParseSymbolTable(&lldb_symtab, symbol_id, symtab);
m_address_class_map.merge(address_class_map);
symbol_id += num_symbols;
}
// The symtab section is non-allocable and can be stripped, while the
// .dynsym section which should always be always be there. To support the
// minidebuginfo case we parse .dynsym when there's a .gnu_debuginfo
// section, nomatter if .symtab was already parsed or not. This is because
// minidebuginfo normally removes the .symtab symbols which have their
// matching .dynsym counterparts.
if (!symtab || GetSectionList()->FindSectionByName(".gnu_debugdata")) {
Section *dynsym =
section_list->FindSectionByType(eSectionTypeELFDynamicSymbols, true)
.get();
if (dynsym) {
auto [num_symbols, address_class_map] =
ParseSymbolTable(&lldb_symtab, symbol_id, dynsym);
symbol_id += num_symbols;
m_address_class_map.merge(address_class_map);
} else {
// Try and read the dynamic symbol table from the .dynamic section.
uint32_t dynamic_num_symbols = 0;
std::optional<DataExtractor> symtab_data =
GetDynsymDataFromDynamic(dynamic_num_symbols);
std::optional<DataExtractor> strtab_data = GetDynstrData();
if (symtab_data && strtab_data) {
auto [num_symbols_parsed, address_class_map] = ParseSymbols(
&lldb_symtab, symbol_id, section_list, dynamic_num_symbols,
symtab_data.value(), strtab_data.value());
symbol_id += num_symbols_parsed;
m_address_class_map.merge(address_class_map);
}
}
}
// DT_JMPREL
// If present, this entry's d_ptr member holds the address of
// relocation
// entries associated solely with the procedure linkage table.
// Separating
// these relocation entries lets the dynamic linker ignore them during
// process initialization, if lazy binding is enabled. If this entry is
// present, the related entries of types DT_PLTRELSZ and DT_PLTREL must
// also be present.
const ELFDynamic *symbol = FindDynamicSymbol(DT_JMPREL);
if (symbol) {
// Synthesize trampoline symbols to help navigate the PLT.
addr_t addr = symbol->d_ptr;
Section *reloc_section =
section_list->FindSectionContainingFileAddress(addr).get();
if (reloc_section) {
user_id_t reloc_id = reloc_section->GetID();
const ELFSectionHeaderInfo *reloc_header =
GetSectionHeaderByIndex(reloc_id);
if (reloc_header)
ParseTrampolineSymbols(&lldb_symtab, symbol_id, reloc_header, reloc_id);
}
}
if (DWARFCallFrameInfo *eh_frame =
GetModule()->GetUnwindTable().GetEHFrameInfo()) {
ParseUnwindSymbols(&lldb_symtab, eh_frame);
}
// In the event that there's no symbol entry for the entry point we'll
// artificially create one. We delegate to the symtab object the figuring
// out of the proper size, this will usually make it span til the next
// symbol it finds in the section. This means that if there are missing
// symbols the entry point might span beyond its function definition.
// We're fine with this as it doesn't make it worse than not having a
// symbol entry at all.
if (CalculateType() == eTypeExecutable) {
ArchSpec arch = GetArchitecture();
auto entry_point_addr = GetEntryPointAddress();
bool is_valid_entry_point =
entry_point_addr.IsValid() && entry_point_addr.IsSectionOffset();
addr_t entry_point_file_addr = entry_point_addr.GetFileAddress();
if (is_valid_entry_point && !lldb_symtab.FindSymbolContainingFileAddress(
entry_point_file_addr)) {
uint64_t symbol_id = lldb_symtab.GetNumSymbols();
// Don't set the name for any synthetic symbols, the Symbol
// object will generate one if needed when the name is accessed
// via accessors.
SectionSP section_sp = entry_point_addr.GetSection();
Symbol symbol(
/*symID=*/symbol_id,
/*name=*/llvm::StringRef(), // Name will be auto generated.
/*type=*/eSymbolTypeCode,
/*external=*/true,
/*is_debug=*/false,
/*is_trampoline=*/false,
/*is_artificial=*/true,
/*section_sp=*/section_sp,
/*offset=*/entry_point_addr.GetOffset(),
/*size=*/0, // FDE can span multiple symbols so don't use its size.
/*size_is_valid=*/false,
/*contains_linker_annotations=*/false,
/*flags=*/0);
// When the entry point is arm thumb we need to explicitly set its
// class address to reflect that. This is important because expression
// evaluation relies on correctly setting a breakpoint at this
// address.
if (arch.GetMachine() == llvm::Triple::arm &&
(entry_point_file_addr & 1)) {
symbol.GetAddressRef().Slide(-1);
m_address_class_map[entry_point_file_addr - 1] =
AddressClass::eCodeAlternateISA;
} else {
m_address_class_map[entry_point_file_addr] = AddressClass::eCode;
}
lldb_symtab.AddSymbol(symbol);
}
}
}
void ObjectFileELF::RelocateSection(lldb_private::Section *section)
{
static llvm::StringRef debug_prefix(".debug");
// Set relocated bit so we stop getting called, regardless of whether we
// actually relocate.
section->SetIsRelocated(true);
// We only relocate in ELF relocatable files
if (CalculateType() != eTypeObjectFile)
return;
llvm::StringRef section_name = section->GetName();
// Can't relocate that which can't be named
if (section_name.empty())
return;
// We don't relocate non-debug sections at the moment
if (!section_name.starts_with(debug_prefix))
return;
// Relocation section names to look for
std::string needle = std::string(".rel") + section_name.str();
std::string needlea = std::string(".rela") + section_name.str();
for (SectionHeaderCollIter I = m_section_headers.begin();
I != m_section_headers.end(); ++I) {
if (I->sh_type == SHT_RELA || I->sh_type == SHT_REL) {
llvm::StringRef hay_name(I->section_name);
if (hay_name.empty())
continue;
if (needle == hay_name || needlea == hay_name) {
const ELFSectionHeader &reloc_header = *I;
user_id_t reloc_id = SectionIndex(I);
RelocateDebugSections(&reloc_header, reloc_id, GetSymtab());
break;
}
}
}
}
void ObjectFileELF::ParseUnwindSymbols(Symtab *symbol_table,
DWARFCallFrameInfo *eh_frame) {
SectionList *section_list = GetSectionList();
if (!section_list)
return;
// First we save the new symbols into a separate list and add them to the
// symbol table after we collected all symbols we want to add. This is
// neccessary because adding a new symbol invalidates the internal index of
// the symtab what causing the next lookup to be slow because it have to
// recalculate the index first.
std::vector<Symbol> new_symbols;
size_t num_symbols = symbol_table->GetNumSymbols();
uint64_t last_symbol_id =
num_symbols ? symbol_table->SymbolAtIndex(num_symbols - 1)->GetID() : 0;
eh_frame->ForEachFDEEntries([&](lldb::addr_t file_addr, uint32_t size,
dw_offset_t) {
Symbol *symbol = symbol_table->FindSymbolAtFileAddress(file_addr);
if (symbol) {
if (!symbol->GetByteSizeIsValid()) {
symbol->SetByteSize(size);
symbol->SetSizeIsSynthesized(true);
}
} else {
SectionSP section_sp =
section_list->FindSectionContainingFileAddress(file_addr);
if (section_sp) {
addr_t offset = file_addr - section_sp->GetFileAddress();
uint64_t symbol_id = ++last_symbol_id;
// Don't set the name for any synthetic symbols, the Symbol
// object will generate one if needed when the name is accessed
// via accessors.
Symbol eh_symbol(
/*symID=*/symbol_id,
/*name=*/llvm::StringRef(), // Name will be auto generated.
/*type=*/eSymbolTypeCode,
/*external=*/true,
/*is_debug=*/false,
/*is_trampoline=*/false,
/*is_artificial=*/true,
/*section_sp=*/section_sp,
/*offset=*/offset,
/*size=*/0, // FDE can span multiple symbols so don't use its size.
/*size_is_valid=*/false,
/*contains_linker_annotations=*/false,
/*flags=*/0);
new_symbols.push_back(eh_symbol);
}
}
return true;
});
for (const Symbol &s : new_symbols)
symbol_table->AddSymbol(s);
}
bool ObjectFileELF::IsStripped() {
// TODO: determine this for ELF
return false;
}
//===----------------------------------------------------------------------===//
// Dump
//
// Dump the specifics of the runtime file container (such as any headers
// segments, sections, etc).
void ObjectFileELF::Dump(Stream *s) {
ModuleSP module_sp(GetModule());
if (!module_sp) {
return;
}
std::lock_guard<std::recursive_mutex> guard(module_sp->GetMutex());
s->Printf("%p: ", static_cast<void *>(this));
s->Indent();
s->PutCString("ObjectFileELF");
ArchSpec header_arch = GetArchitecture();
*s << ", file = '" << m_file
<< "', arch = " << header_arch.GetArchitectureName();
if (m_memory_addr != LLDB_INVALID_ADDRESS)
s->Printf(", addr = %#16.16" PRIx64, m_memory_addr);
s->EOL();
DumpELFHeader(s, m_header);
s->EOL();
DumpELFProgramHeaders(s);
s->EOL();
DumpELFSectionHeaders(s);
s->EOL();
SectionList *section_list = GetSectionList();
if (section_list)
section_list->Dump(s->AsRawOstream(), s->GetIndentLevel(), nullptr, true,
UINT32_MAX);
Symtab *symtab = GetSymtab();
if (symtab)
symtab->Dump(s, nullptr, eSortOrderNone);
s->EOL();
DumpDependentModules(s);
s->EOL();
DumpELFDynamic(s);
s->EOL();
Address image_info_addr = GetImageInfoAddress(nullptr);
if (image_info_addr.IsValid())
s->Printf("image_info_address = %#16.16" PRIx64 "\n",
image_info_addr.GetFileAddress());
}
// DumpELFHeader
//
// Dump the ELF header to the specified output stream
void ObjectFileELF::DumpELFHeader(Stream *s, const ELFHeader &header) {
s->PutCString("ELF Header\n");
s->Printf("e_ident[EI_MAG0 ] = 0x%2.2x\n", header.e_ident[EI_MAG0]);
s->Printf("e_ident[EI_MAG1 ] = 0x%2.2x '%c'\n", header.e_ident[EI_MAG1],
header.e_ident[EI_MAG1]);
s->Printf("e_ident[EI_MAG2 ] = 0x%2.2x '%c'\n", header.e_ident[EI_MAG2],
header.e_ident[EI_MAG2]);
s->Printf("e_ident[EI_MAG3 ] = 0x%2.2x '%c'\n", header.e_ident[EI_MAG3],
header.e_ident[EI_MAG3]);
s->Printf("e_ident[EI_CLASS ] = 0x%2.2x\n", header.e_ident[EI_CLASS]);
s->Printf("e_ident[EI_DATA ] = 0x%2.2x ", header.e_ident[EI_DATA]);
DumpELFHeader_e_ident_EI_DATA(s, header.e_ident[EI_DATA]);
s->Printf("\ne_ident[EI_VERSION] = 0x%2.2x\n", header.e_ident[EI_VERSION]);
s->Printf("e_ident[EI_PAD ] = 0x%2.2x\n", header.e_ident[EI_PAD]);
s->Printf("e_type = 0x%4.4x ", header.e_type);
DumpELFHeader_e_type(s, header.e_type);
s->Printf("\ne_machine = 0x%4.4x\n", header.e_machine);
s->Printf("e_version = 0x%8.8x\n", header.e_version);
s->Printf("e_entry = 0x%8.8" PRIx64 "\n", header.e_entry);
s->Printf("e_phoff = 0x%8.8" PRIx64 "\n", header.e_phoff);
s->Printf("e_shoff = 0x%8.8" PRIx64 "\n", header.e_shoff);
s->Printf("e_flags = 0x%8.8x\n", header.e_flags);
s->Printf("e_ehsize = 0x%4.4x\n", header.e_ehsize);
s->Printf("e_phentsize = 0x%4.4x\n", header.e_phentsize);
s->Printf("e_phnum = 0x%8.8x\n", header.e_phnum);
s->Printf("e_shentsize = 0x%4.4x\n", header.e_shentsize);
s->Printf("e_shnum = 0x%8.8x\n", header.e_shnum);
s->Printf("e_shstrndx = 0x%8.8x\n", header.e_shstrndx);
}
// DumpELFHeader_e_type
//
// Dump an token value for the ELF header member e_type
void ObjectFileELF::DumpELFHeader_e_type(Stream *s, elf_half e_type) {
switch (e_type) {
case ET_NONE:
*s << "ET_NONE";
break;
case ET_REL:
*s << "ET_REL";
break;
case ET_EXEC:
*s << "ET_EXEC";
break;
case ET_DYN:
*s << "ET_DYN";
break;
case ET_CORE:
*s << "ET_CORE";
break;
default:
break;
}
}
// DumpELFHeader_e_ident_EI_DATA
//
// Dump an token value for the ELF header member e_ident[EI_DATA]
void ObjectFileELF::DumpELFHeader_e_ident_EI_DATA(Stream *s,
unsigned char ei_data) {
switch (ei_data) {
case ELFDATANONE:
*s << "ELFDATANONE";
break;
case ELFDATA2LSB:
*s << "ELFDATA2LSB - Little Endian";
break;
case ELFDATA2MSB:
*s << "ELFDATA2MSB - Big Endian";
break;
default:
break;
}
}
// DumpELFProgramHeader
//
// Dump a single ELF program header to the specified output stream
void ObjectFileELF::DumpELFProgramHeader(Stream *s,
const ELFProgramHeader &ph) {
DumpELFProgramHeader_p_type(s, ph.p_type);
s->Printf(" %8.8" PRIx64 " %8.8" PRIx64 " %8.8" PRIx64, ph.p_offset,
ph.p_vaddr, ph.p_paddr);
s->Printf(" %8.8" PRIx64 " %8.8" PRIx64 " %8.8x (", ph.p_filesz, ph.p_memsz,
ph.p_flags);
DumpELFProgramHeader_p_flags(s, ph.p_flags);
s->Printf(") %8.8" PRIx64, ph.p_align);
}
// DumpELFProgramHeader_p_type
//
// Dump an token value for the ELF program header member p_type which describes
// the type of the program header
void ObjectFileELF::DumpELFProgramHeader_p_type(Stream *s, elf_word p_type) {
const int kStrWidth = 15;
switch (p_type) {
CASE_AND_STREAM(s, PT_NULL, kStrWidth);
CASE_AND_STREAM(s, PT_LOAD, kStrWidth);
CASE_AND_STREAM(s, PT_DYNAMIC, kStrWidth);
CASE_AND_STREAM(s, PT_INTERP, kStrWidth);
CASE_AND_STREAM(s, PT_NOTE, kStrWidth);
CASE_AND_STREAM(s, PT_SHLIB, kStrWidth);
CASE_AND_STREAM(s, PT_PHDR, kStrWidth);
CASE_AND_STREAM(s, PT_TLS, kStrWidth);
CASE_AND_STREAM(s, PT_GNU_EH_FRAME, kStrWidth);
default:
s->Printf("0x%8.8x%*s", p_type, kStrWidth - 10, "");
break;
}
}
// DumpELFProgramHeader_p_flags
//
// Dump an token value for the ELF program header member p_flags
void ObjectFileELF::DumpELFProgramHeader_p_flags(Stream *s, elf_word p_flags) {
*s << ((p_flags & PF_X) ? "PF_X" : " ")
<< (((p_flags & PF_X) && (p_flags & PF_W)) ? '+' : ' ')
<< ((p_flags & PF_W) ? "PF_W" : " ")
<< (((p_flags & PF_W) && (p_flags & PF_R)) ? '+' : ' ')
<< ((p_flags & PF_R) ? "PF_R" : " ");
}
// DumpELFProgramHeaders
//
// Dump all of the ELF program header to the specified output stream
void ObjectFileELF::DumpELFProgramHeaders(Stream *s) {
if (!ParseProgramHeaders())
return;
s->PutCString("Program Headers\n");
s->PutCString("IDX p_type p_offset p_vaddr p_paddr "
"p_filesz p_memsz p_flags p_align\n");
s->PutCString("==== --------------- -------- -------- -------- "
"-------- -------- ------------------------- --------\n");
for (const auto &H : llvm::enumerate(m_program_headers)) {
s->Format("[{0,2}] ", H.index());
ObjectFileELF::DumpELFProgramHeader(s, H.value());
s->EOL();
}
}
// DumpELFSectionHeader
//
// Dump a single ELF section header to the specified output stream
void ObjectFileELF::DumpELFSectionHeader(Stream *s,
const ELFSectionHeaderInfo &sh) {
s->Printf("%8.8x ", sh.sh_name);
DumpELFSectionHeader_sh_type(s, sh.sh_type);
s->Printf(" %8.8" PRIx64 " (", sh.sh_flags);
DumpELFSectionHeader_sh_flags(s, sh.sh_flags);
s->Printf(") %8.8" PRIx64 " %8.8" PRIx64 " %8.8" PRIx64, sh.sh_addr,
sh.sh_offset, sh.sh_size);
s->Printf(" %8.8x %8.8x", sh.sh_link, sh.sh_info);
s->Printf(" %8.8" PRIx64 " %8.8" PRIx64, sh.sh_addralign, sh.sh_entsize);
}
// DumpELFSectionHeader_sh_type
//
// Dump an token value for the ELF section header member sh_type which
// describes the type of the section
void ObjectFileELF::DumpELFSectionHeader_sh_type(Stream *s, elf_word sh_type) {
const int kStrWidth = 12;
switch (sh_type) {
CASE_AND_STREAM(s, SHT_NULL, kStrWidth);
CASE_AND_STREAM(s, SHT_PROGBITS, kStrWidth);
CASE_AND_STREAM(s, SHT_SYMTAB, kStrWidth);
CASE_AND_STREAM(s, SHT_STRTAB, kStrWidth);
CASE_AND_STREAM(s, SHT_RELA, kStrWidth);
CASE_AND_STREAM(s, SHT_HASH, kStrWidth);
CASE_AND_STREAM(s, SHT_DYNAMIC, kStrWidth);
CASE_AND_STREAM(s, SHT_NOTE, kStrWidth);
CASE_AND_STREAM(s, SHT_NOBITS, kStrWidth);
CASE_AND_STREAM(s, SHT_REL, kStrWidth);
CASE_AND_STREAM(s, SHT_SHLIB, kStrWidth);
CASE_AND_STREAM(s, SHT_DYNSYM, kStrWidth);
CASE_AND_STREAM(s, SHT_LOPROC, kStrWidth);
CASE_AND_STREAM(s, SHT_HIPROC, kStrWidth);
CASE_AND_STREAM(s, SHT_LOUSER, kStrWidth);
CASE_AND_STREAM(s, SHT_HIUSER, kStrWidth);
default:
s->Printf("0x%8.8x%*s", sh_type, kStrWidth - 10, "");
break;
}
}
// DumpELFSectionHeader_sh_flags
//
// Dump an token value for the ELF section header member sh_flags
void ObjectFileELF::DumpELFSectionHeader_sh_flags(Stream *s,
elf_xword sh_flags) {
*s << ((sh_flags & SHF_WRITE) ? "WRITE" : " ")
<< (((sh_flags & SHF_WRITE) && (sh_flags & SHF_ALLOC)) ? '+' : ' ')
<< ((sh_flags & SHF_ALLOC) ? "ALLOC" : " ")
<< (((sh_flags & SHF_ALLOC) && (sh_flags & SHF_EXECINSTR)) ? '+' : ' ')
<< ((sh_flags & SHF_EXECINSTR) ? "EXECINSTR" : " ");
}
// DumpELFSectionHeaders
//
// Dump all of the ELF section header to the specified output stream
void ObjectFileELF::DumpELFSectionHeaders(Stream *s) {
if (!ParseSectionHeaders())
return;
s->PutCString("Section Headers\n");
s->PutCString("IDX name type flags "
"addr offset size link info addralgn "
"entsize Name\n");
s->PutCString("==== -------- ------------ -------------------------------- "
"-------- -------- -------- -------- -------- -------- "
"-------- ====================\n");
uint32_t idx = 0;
for (SectionHeaderCollConstIter I = m_section_headers.begin();
I != m_section_headers.end(); ++I, ++idx) {
s->Printf("[%2u] ", idx);
ObjectFileELF::DumpELFSectionHeader(s, *I);
const std::string &section_name = I->section_name;
if (!section_name.empty())
*s << ' ' << section_name << "\n";
}
}
void ObjectFileELF::DumpDependentModules(lldb_private::Stream *s) {
size_t num_modules = ParseDependentModules();
if (num_modules > 0) {
s->PutCString("Dependent Modules:\n");
for (unsigned i = 0; i < num_modules; ++i) {
const FileSpec &spec = m_filespec_up->GetFileSpecAtIndex(i);
s->Format(" {0}\n", spec.GetFilename());
}
}
}
std::string static getDynamicTagAsString(uint16_t Arch, uint64_t Type) {
#define DYNAMIC_STRINGIFY_ENUM(tag, value) \
case value: \
return #tag;
#define DYNAMIC_TAG(n, v)
switch (Arch) {
case llvm::ELF::EM_AARCH64:
switch (Type) {
#define AARCH64_DYNAMIC_TAG(name, value) DYNAMIC_STRINGIFY_ENUM(name, value)
#include "llvm/BinaryFormat/DynamicTags.def"
#undef AARCH64_DYNAMIC_TAG
}
break;
case llvm::ELF::EM_HEXAGON:
switch (Type) {
#define HEXAGON_DYNAMIC_TAG(name, value) DYNAMIC_STRINGIFY_ENUM(name, value)
#include "llvm/BinaryFormat/DynamicTags.def"
#undef HEXAGON_DYNAMIC_TAG
}
break;
case llvm::ELF::EM_MIPS:
switch (Type) {
#define MIPS_DYNAMIC_TAG(name, value) DYNAMIC_STRINGIFY_ENUM(name, value)
#include "llvm/BinaryFormat/DynamicTags.def"
#undef MIPS_DYNAMIC_TAG
}
break;
case llvm::ELF::EM_PPC:
switch (Type) {
#define PPC_DYNAMIC_TAG(name, value) DYNAMIC_STRINGIFY_ENUM(name, value)
#include "llvm/BinaryFormat/DynamicTags.def"
#undef PPC_DYNAMIC_TAG
}
break;
case llvm::ELF::EM_PPC64:
switch (Type) {
#define PPC64_DYNAMIC_TAG(name, value) DYNAMIC_STRINGIFY_ENUM(name, value)
#include "llvm/BinaryFormat/DynamicTags.def"
#undef PPC64_DYNAMIC_TAG
}
break;
case llvm::ELF::EM_RISCV:
switch (Type) {
#define RISCV_DYNAMIC_TAG(name, value) DYNAMIC_STRINGIFY_ENUM(name, value)
#include "llvm/BinaryFormat/DynamicTags.def"
#undef RISCV_DYNAMIC_TAG
}
break;
case llvm::ELF::EM_SPARC:
case llvm::ELF::EM_SPARC32PLUS:
case llvm::ELF::EM_SPARCV9:
switch (Type) {
#define SPARC_DYNAMIC_TAG(name, value) DYNAMIC_STRINGIFY_ENUM(name, value)
#include "llvm/BinaryFormat/DynamicTags.def"
#undef SPARC_DYNAMIC_TAG
}
break;
case llvm::ELF::EM_X86_64:
switch (Type) {
#define X86_64_DYNAMIC_TAG(name, value) DYNAMIC_STRINGIFY_ENUM(name, value)
#include "llvm/BinaryFormat/DynamicTags.def"
#undef X86_64_DYNAMIC_TAG
}
break;
}
#undef DYNAMIC_TAG
switch (Type) {
// Now handle all dynamic tags except the architecture specific ones
#define AARCH64_DYNAMIC_TAG(name, value)
#define MIPS_DYNAMIC_TAG(name, value)
#define HEXAGON_DYNAMIC_TAG(name, value)
#define PPC_DYNAMIC_TAG(name, value)
#define PPC64_DYNAMIC_TAG(name, value)
#define RISCV_DYNAMIC_TAG(name, value)
#define SPARC_DYNAMIC_TAG(name, value)
#define X86_64_DYNAMIC_TAG(name, value)
// Also ignore marker tags such as DT_HIOS (maps to DT_VERNEEDNUM), etc.
#define DYNAMIC_TAG_MARKER(name, value)
#define DYNAMIC_TAG(name, value) \
case value: \
return #name;
#include "llvm/BinaryFormat/DynamicTags.def"
#undef DYNAMIC_TAG
#undef AARCH64_DYNAMIC_TAG
#undef MIPS_DYNAMIC_TAG
#undef HEXAGON_DYNAMIC_TAG
#undef PPC_DYNAMIC_TAG
#undef PPC64_DYNAMIC_TAG
#undef RISCV_DYNAMIC_TAG
#undef SPARC_DYNAMIC_TAG
#undef X86_64_DYNAMIC_TAG
#undef DYNAMIC_TAG_MARKER
#undef DYNAMIC_STRINGIFY_ENUM
default:
return "<unknown:>0x" + llvm::utohexstr(Type, true);
}
}
void ObjectFileELF::DumpELFDynamic(lldb_private::Stream *s) {
ParseDynamicSymbols();
if (m_dynamic_symbols.empty())
return;
s->PutCString(".dynamic:\n");
s->PutCString("IDX d_tag d_val/d_ptr\n");
s->PutCString("==== ---------------- ------------------\n");
uint32_t idx = 0;
for (const auto &entry : m_dynamic_symbols) {
s->Printf("[%2u] ", idx++);
s->Printf(
"%-16s 0x%16.16" PRIx64,
getDynamicTagAsString(m_header.e_machine, entry.symbol.d_tag).c_str(),
entry.symbol.d_ptr);
if (!entry.name.empty())
s->Printf(" \"%s\"", entry.name.c_str());
s->EOL();
}
}
ArchSpec ObjectFileELF::GetArchitecture() {
if (!ParseHeader())
return ArchSpec();
if (m_section_headers.empty()) {
// Allow elf notes to be parsed which may affect the detected architecture.
ParseSectionHeaders();
}
if (CalculateType() == eTypeCoreFile &&
!m_arch_spec.TripleOSWasSpecified()) {
// Core files don't have section headers yet they have PT_NOTE program
// headers that might shed more light on the architecture
for (const elf::ELFProgramHeader &H : ProgramHeaders()) {
if (H.p_type != PT_NOTE || H.p_offset == 0 || H.p_filesz == 0)
continue;
DataExtractor data;
if (data.SetData(*m_data_nsp, H.p_offset, H.p_filesz) == H.p_filesz) {
UUID uuid;
RefineModuleDetailsFromNote(data, m_arch_spec, uuid);
}
}
}
return m_arch_spec;
}
ObjectFile::Type ObjectFileELF::CalculateType() {
switch (m_header.e_type) {
case llvm::ELF::ET_NONE:
// 0 - No file type
return eTypeUnknown;
case llvm::ELF::ET_REL:
// 1 - Relocatable file
return eTypeObjectFile;
case llvm::ELF::ET_EXEC:
// 2 - Executable file
return eTypeExecutable;
case llvm::ELF::ET_DYN:
// 3 - Shared object file
return eTypeSharedLibrary;
case ET_CORE:
// 4 - Core file
return eTypeCoreFile;
default:
break;
}
return eTypeUnknown;
}
ObjectFile::Strata ObjectFileELF::CalculateStrata() {
switch (m_header.e_type) {
case llvm::ELF::ET_NONE:
// 0 - No file type
return eStrataUnknown;
case llvm::ELF::ET_REL:
// 1 - Relocatable file
return eStrataUnknown;
case llvm::ELF::ET_EXEC:
// 2 - Executable file
{
SectionList *section_list = GetSectionList();
if (section_list) {
llvm::StringRef loader_section_name(".interp");
SectionSP loader_section =
section_list->FindSectionByName(loader_section_name);
if (loader_section) {
char buffer[256];
size_t read_size =
ReadSectionData(loader_section.get(), 0, buffer, sizeof(buffer));
// We compare the content of .interp section
// It will contains \0 when counting read_size, so the size needs to
// decrease by one
llvm::StringRef loader_name(buffer, read_size - 1);
llvm::StringRef freebsd_kernel_loader_name("/red/herring");
if (loader_name == freebsd_kernel_loader_name)
return eStrataKernel;
}
}
return eStrataUser;
}
case llvm::ELF::ET_DYN:
// 3 - Shared object file
// TODO: is there any way to detect that an shared library is a kernel
// related executable by inspecting the program headers, section headers,
// symbols, or any other flag bits???
return eStrataUnknown;
case ET_CORE:
// 4 - Core file
// TODO: is there any way to detect that an core file is a kernel
// related executable by inspecting the program headers, section headers,
// symbols, or any other flag bits???
return eStrataUnknown;
default:
break;
}
return eStrataUnknown;
}
size_t ObjectFileELF::ReadSectionData(Section *section,
lldb::offset_t section_offset, void *dst,
size_t dst_len) {
// If some other objectfile owns this data, pass this to them.
if (section->GetObjectFile() != this)
return section->GetObjectFile()->ReadSectionData(section, section_offset,
dst, dst_len);
if (!section->Test(SHF_COMPRESSED))
return ObjectFile::ReadSectionData(section, section_offset, dst, dst_len);
// For compressed sections we need to read to full data to be able to
// decompress.
DataExtractor data;
ReadSectionData(section, data);
return data.CopyData(section_offset, dst_len, dst);
}
size_t ObjectFileELF::ReadSectionData(Section *section,
DataExtractor &section_data) {
// If some other objectfile owns this data, pass this to them.
if (section->GetObjectFile() != this)
return section->GetObjectFile()->ReadSectionData(section, section_data);
size_t result = ObjectFile::ReadSectionData(section, section_data);
if (result == 0 || !(section->Get() & llvm::ELF::SHF_COMPRESSED))
return result;
auto Decompressor = llvm::object::Decompressor::create(
section->GetName(),
{reinterpret_cast<const char *>(section_data.GetDataStart()),
size_t(section_data.GetByteSize())},
GetByteOrder() == eByteOrderLittle, GetAddressByteSize() == 8);
if (!Decompressor) {
GetModule()->ReportWarning(
"unable to initialize decompressor for section '{0}': {1}",
section->GetName(), llvm::toString(Decompressor.takeError()).c_str());
section_data.Clear();
return 0;
}
auto buffer_sp =
std::make_shared<DataBufferHeap>(Decompressor->getDecompressedSize(), 0);
if (auto error = Decompressor->decompress(
{buffer_sp->GetBytes(), size_t(buffer_sp->GetByteSize())})) {
GetModule()->ReportWarning("decompression of section '{0}' failed: {1}",
section->GetName(),
llvm::toString(std::move(error)).c_str());
section_data.Clear();
return 0;
}
section_data.SetData(buffer_sp);
return buffer_sp->GetByteSize();
}
llvm::ArrayRef<ELFProgramHeader> ObjectFileELF::ProgramHeaders() {
ParseProgramHeaders();
return m_program_headers;
}
DataExtractor ObjectFileELF::GetSegmentData(const ELFProgramHeader &H) {
// Try and read the program header from our cached m_data_nsp which can come
// from the file on disk being mmap'ed or from the initial part of the ELF
// file we read from memory and cached.
DataExtractor data = DataExtractor(*m_data_nsp, H.p_offset, H.p_filesz);
if (data.GetByteSize() == H.p_filesz)
return data;
if (IsInMemory()) {
// We have a ELF file in process memory, read the program header data from
// the process.
if (ProcessSP process_sp = m_process_wp.lock()) {
const lldb::offset_t base_file_addr = GetBaseAddress().GetFileAddress();
const addr_t load_bias = m_memory_addr - base_file_addr;
const addr_t data_addr = H.p_vaddr + load_bias;
if (DataBufferSP data_sp = ReadMemory(process_sp, data_addr, H.p_memsz))
return DataExtractor(data_sp, GetByteOrder(), GetAddressByteSize());
}
}
return DataExtractor();
}
bool ObjectFileELF::AnySegmentHasPhysicalAddress() {
for (const ELFProgramHeader &H : ProgramHeaders()) {
if (H.p_paddr != 0)
return true;
}
return false;
}
std::vector<ObjectFile::LoadableData>
ObjectFileELF::GetLoadableData(Target &target) {
// Create a list of loadable data from loadable segments, using physical
// addresses if they aren't all null
std::vector<LoadableData> loadables;
bool should_use_paddr = AnySegmentHasPhysicalAddress();
for (const ELFProgramHeader &H : ProgramHeaders()) {
LoadableData loadable;
if (H.p_type != llvm::ELF::PT_LOAD)
continue;
loadable.Dest = should_use_paddr ? H.p_paddr : H.p_vaddr;
if (loadable.Dest == LLDB_INVALID_ADDRESS)
continue;
if (H.p_filesz == 0)
continue;
auto segment_data = GetSegmentData(H);
loadable.Contents = llvm::ArrayRef<uint8_t>(segment_data.GetDataStart(),
segment_data.GetByteSize());
loadables.push_back(loadable);
}
return loadables;
}
lldb::WritableDataBufferSP
ObjectFileELF::MapFileDataWritable(const FileSpec &file, uint64_t Size,
uint64_t Offset) {
return FileSystem::Instance().CreateWritableDataBuffer(file.GetPath(), Size,
Offset);
}
std::optional<DataExtractor>
ObjectFileELF::ReadDataFromDynamic(const ELFDynamic *dyn, uint64_t length,
uint64_t offset) {
// ELFDynamic values contain a "d_ptr" member that will be a load address if
// we have an ELF file read from memory, or it will be a file address if it
// was read from a ELF file. This function will correctly fetch data pointed
// to by the ELFDynamic::d_ptr, or return std::nullopt if the data isn't
// available.
const lldb::addr_t d_ptr_addr = dyn->d_ptr + offset;
if (ProcessSP process_sp = m_process_wp.lock()) {
if (DataBufferSP data_sp = ReadMemory(process_sp, d_ptr_addr, length))
return DataExtractor(data_sp, GetByteOrder(), GetAddressByteSize());
} else {
// We have an ELF file with no section headers or we didn't find the
// .dynamic section. Try and find the .dynstr section.
Address addr;
if (!addr.ResolveAddressUsingFileSections(d_ptr_addr, GetSectionList()))
return std::nullopt;
DataExtractor data;
addr.GetSection()->GetSectionData(data);
return DataExtractor(data, d_ptr_addr - addr.GetSection()->GetFileAddress(),
length);
}
return std::nullopt;
}
std::optional<DataExtractor> ObjectFileELF::GetDynstrData() {
if (SectionList *section_list = GetSectionList()) {
// Find the SHT_DYNAMIC section.
if (Section *dynamic =
section_list
->FindSectionByType(eSectionTypeELFDynamicLinkInfo, true)
.get()) {
assert(dynamic->GetObjectFile() == this);
if (const ELFSectionHeaderInfo *header =
GetSectionHeaderByIndex(dynamic->GetID())) {
// sh_link: section header index of string table used by entries in
// the section.
if (Section *dynstr =
section_list->FindSectionByID(header->sh_link).get()) {
DataExtractor data;
if (ReadSectionData(dynstr, data))
return data;
}
}
}
}
// Every ELF file which represents an executable or shared library has
// mandatory .dynamic entries. Two of these values are DT_STRTAB and DT_STRSZ
// and represent the dynamic symbol tables's string table. These are needed
// by the dynamic loader and we can read them from a process' address space.
//
// When loading and ELF file from memory, only the program headers are
// guaranteed end up being mapped into memory, and we can find these values in
// the PT_DYNAMIC segment.
const ELFDynamic *strtab = FindDynamicSymbol(DT_STRTAB);
const ELFDynamic *strsz = FindDynamicSymbol(DT_STRSZ);
if (strtab == nullptr || strsz == nullptr)
return std::nullopt;
return ReadDataFromDynamic(strtab, strsz->d_val, /*offset=*/0);
}
std::optional<lldb_private::DataExtractor> ObjectFileELF::GetDynamicData() {
DataExtractor data;
// The PT_DYNAMIC program header describes where the .dynamic section is and
// doesn't require parsing section headers. The PT_DYNAMIC is required by
// executables and shared libraries so it will always be available.
for (const ELFProgramHeader &H : ProgramHeaders()) {
if (H.p_type == llvm::ELF::PT_DYNAMIC) {
data = GetSegmentData(H);
if (data.GetByteSize() > 0) {
m_dynamic_base_addr = H.p_vaddr;
return data;
}
}
}
// Fall back to using section headers.
if (SectionList *section_list = GetSectionList()) {
// Find the SHT_DYNAMIC section.
if (Section *dynamic =
section_list
->FindSectionByType(eSectionTypeELFDynamicLinkInfo, true)
.get()) {
assert(dynamic->GetObjectFile() == this);
if (ReadSectionData(dynamic, data)) {
m_dynamic_base_addr = dynamic->GetFileAddress();
return data;
}
}
}
return std::nullopt;
}
std::optional<uint32_t> ObjectFileELF::GetNumSymbolsFromDynamicHash() {
const ELFDynamic *hash = FindDynamicSymbol(DT_HASH);
if (hash == nullptr)
return std::nullopt;
// The DT_HASH header looks like this:
struct DtHashHeader {
uint32_t nbucket;
uint32_t nchain;
};
if (auto data = ReadDataFromDynamic(hash, 8)) {
// We don't need the number of buckets value "nbucket", we just need the
// "nchain" value which contains the number of symbols.
offset_t offset = offsetof(DtHashHeader, nchain);
return data->GetU32(&offset);
}
return std::nullopt;
}
std::optional<uint32_t> ObjectFileELF::GetNumSymbolsFromDynamicGnuHash() {
const ELFDynamic *gnu_hash = FindDynamicSymbol(DT_GNU_HASH);
if (gnu_hash == nullptr)
return std::nullopt;
// Create a DT_GNU_HASH header
// https://flapenguin.me/elf-dt-gnu-hash
struct DtGnuHashHeader {
uint32_t nbuckets = 0;
uint32_t symoffset = 0;
uint32_t bloom_size = 0;
uint32_t bloom_shift = 0;
};
uint32_t num_symbols = 0;
// Read enogh data for the DT_GNU_HASH header so we can extract the values.
if (auto data = ReadDataFromDynamic(gnu_hash, sizeof(DtGnuHashHeader))) {
offset_t offset = 0;
DtGnuHashHeader header;
header.nbuckets = data->GetU32(&offset);
header.symoffset = data->GetU32(&offset);
header.bloom_size = data->GetU32(&offset);
header.bloom_shift = data->GetU32(&offset);
const size_t addr_size = GetAddressByteSize();
const addr_t buckets_offset =
sizeof(DtGnuHashHeader) + addr_size * header.bloom_size;
std::vector<uint32_t> buckets;
if (auto bucket_data = ReadDataFromDynamic(gnu_hash, header.nbuckets * 4,
buckets_offset)) {
offset = 0;
for (uint32_t i = 0; i < header.nbuckets; ++i)
buckets.push_back(bucket_data->GetU32(&offset));
// Locate the chain that handles the largest index bucket.
uint32_t last_symbol = 0;
for (uint32_t bucket_value : buckets)
last_symbol = std::max(bucket_value, last_symbol);
if (last_symbol < header.symoffset) {
num_symbols = header.symoffset;
} else {
// Walk the bucket's chain to add the chain length to the total.
const addr_t chains_base_offset = buckets_offset + header.nbuckets * 4;
for (;;) {
if (auto chain_entry_data = ReadDataFromDynamic(
gnu_hash, 4,
chains_base_offset + (last_symbol - header.symoffset) * 4)) {
offset = 0;
uint32_t chain_entry = chain_entry_data->GetU32(&offset);
++last_symbol;
// If the low bit is set, this entry is the end of the chain.
if (chain_entry & 1)
break;
} else {
break;
}
}
num_symbols = last_symbol;
}
}
}
if (num_symbols > 0)
return num_symbols;
return std::nullopt;
}
std::optional<DataExtractor>
ObjectFileELF::GetDynsymDataFromDynamic(uint32_t &num_symbols) {
// Every ELF file which represents an executable or shared library has
// mandatory .dynamic entries. The DT_SYMTAB value contains a pointer to the
// symbol table, and DT_SYMENT contains the size of a symbol table entry.
// We then can use either the DT_HASH or DT_GNU_HASH to find the number of
// symbols in the symbol table as the symbol count is not stored in the
// .dynamic section as a key/value pair.
//
// When loading and ELF file from memory, only the program headers end up
// being mapped into memory, and we can find these values in the PT_DYNAMIC
// segment.
num_symbols = 0;
// Get the process in case this is an in memory ELF file.
ProcessSP process_sp(m_process_wp.lock());
const ELFDynamic *symtab = FindDynamicSymbol(DT_SYMTAB);
const ELFDynamic *syment = FindDynamicSymbol(DT_SYMENT);
// DT_SYMTAB and DT_SYMENT are mandatory.
if (symtab == nullptr || syment == nullptr)
return std::nullopt;
if (std::optional<uint32_t> syms = GetNumSymbolsFromDynamicHash())
num_symbols = *syms;
else if (std::optional<uint32_t> syms = GetNumSymbolsFromDynamicGnuHash())
num_symbols = *syms;
else
return std::nullopt;
if (num_symbols == 0)
return std::nullopt;
return ReadDataFromDynamic(symtab, syment->d_val * num_symbols);
}