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//===-- LLVMSymbolize.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
//
//===----------------------------------------------------------------------===//
//
// Implementation for LLVM symbolization library.
//
//===----------------------------------------------------------------------===//
#include "llvm/DebugInfo/Symbolize/Symbolize.h"
#include "SymbolizableObjectFile.h"
#include "llvm/ADT/STLExtras.h"
#include "llvm/BinaryFormat/COFF.h"
#include "llvm/DebugInfo/DWARF/DWARFContext.h"
#include "llvm/DebugInfo/PDB/PDB.h"
#include "llvm/DebugInfo/PDB/PDBContext.h"
#include "llvm/Demangle/Demangle.h"
#include "llvm/Object/COFF.h"
#include "llvm/Object/MachO.h"
#include "llvm/Object/MachOUniversal.h"
#include "llvm/Support/CRC.h"
#include "llvm/Support/Casting.h"
#include "llvm/Support/Compression.h"
#include "llvm/Support/DataExtractor.h"
#include "llvm/Support/Errc.h"
#include "llvm/Support/FileSystem.h"
#include "llvm/Support/MemoryBuffer.h"
#include "llvm/Support/Path.h"
#include <algorithm>
#include <cassert>
#include <cstring>
namespace llvm {
namespace symbolize {
Expected<DILineInfo>
LLVMSymbolizer::symbolizeCodeCommon(SymbolizableModule *Info,
object::SectionedAddress ModuleOffset) {
// A null module means an error has already been reported. Return an empty
// result.
if (!Info)
return DILineInfo();
// If the user is giving us relative addresses, add the preferred base of the
// object to the offset before we do the query. It's what DIContext expects.
if (Opts.RelativeAddresses)
ModuleOffset.Address += Info->getModulePreferredBase();
DILineInfo LineInfo = Info->symbolizeCode(ModuleOffset, Opts.PrintFunctions,
Opts.UseSymbolTable);
if (Opts.Demangle)
LineInfo.FunctionName = DemangleName(LineInfo.FunctionName, Info);
return LineInfo;
}
Expected<DILineInfo>
LLVMSymbolizer::symbolizeCode(const ObjectFile &Obj,
object::SectionedAddress ModuleOffset) {
StringRef ModuleName = Obj.getFileName();
auto I = Modules.find(ModuleName);
if (I != Modules.end())
return symbolizeCodeCommon(I->second.get(), ModuleOffset);
std::unique_ptr<DIContext> Context =
DWARFContext::create(Obj, nullptr, DWARFContext::defaultErrorHandler);
Expected<SymbolizableModule *> InfoOrErr =
createModuleInfo(&Obj, std::move(Context), ModuleName);
if (!InfoOrErr)
return InfoOrErr.takeError();
return symbolizeCodeCommon(*InfoOrErr, ModuleOffset);
}
Expected<DILineInfo>
LLVMSymbolizer::symbolizeCode(const std::string &ModuleName,
object::SectionedAddress ModuleOffset) {
Expected<SymbolizableModule *> InfoOrErr = getOrCreateModuleInfo(ModuleName);
if (!InfoOrErr)
return InfoOrErr.takeError();
return symbolizeCodeCommon(*InfoOrErr, ModuleOffset);
}
Expected<DIInliningInfo>
LLVMSymbolizer::symbolizeInlinedCode(const std::string &ModuleName,
object::SectionedAddress ModuleOffset) {
SymbolizableModule *Info;
if (auto InfoOrErr = getOrCreateModuleInfo(ModuleName))
Info = InfoOrErr.get();
else
return InfoOrErr.takeError();
// A null module means an error has already been reported. Return an empty
// result.
if (!Info)
return DIInliningInfo();
// If the user is giving us relative addresses, add the preferred base of the
// object to the offset before we do the query. It's what DIContext expects.
if (Opts.RelativeAddresses)
ModuleOffset.Address += Info->getModulePreferredBase();
DIInliningInfo InlinedContext = Info->symbolizeInlinedCode(
ModuleOffset, Opts.PrintFunctions, Opts.UseSymbolTable);
if (Opts.Demangle) {
for (int i = 0, n = InlinedContext.getNumberOfFrames(); i < n; i++) {
auto *Frame = InlinedContext.getMutableFrame(i);
Frame->FunctionName = DemangleName(Frame->FunctionName, Info);
}
}
return InlinedContext;
}
Expected<DIGlobal>
LLVMSymbolizer::symbolizeData(const std::string &ModuleName,
object::SectionedAddress ModuleOffset) {
SymbolizableModule *Info;
if (auto InfoOrErr = getOrCreateModuleInfo(ModuleName))
Info = InfoOrErr.get();
else
return InfoOrErr.takeError();
// A null module means an error has already been reported. Return an empty
// result.
if (!Info)
return DIGlobal();
// If the user is giving us relative addresses, add the preferred base of
// the object to the offset before we do the query. It's what DIContext
// expects.
if (Opts.RelativeAddresses)
ModuleOffset.Address += Info->getModulePreferredBase();
DIGlobal Global = Info->symbolizeData(ModuleOffset);
if (Opts.Demangle)
Global.Name = DemangleName(Global.Name, Info);
return Global;
}
Expected<std::vector<DILocal>>
LLVMSymbolizer::symbolizeFrame(const std::string &ModuleName,
object::SectionedAddress ModuleOffset) {
SymbolizableModule *Info;
if (auto InfoOrErr = getOrCreateModuleInfo(ModuleName))
Info = InfoOrErr.get();
else
return InfoOrErr.takeError();
// A null module means an error has already been reported. Return an empty
// result.
if (!Info)
return std::vector<DILocal>();
// If the user is giving us relative addresses, add the preferred base of
// the object to the offset before we do the query. It's what DIContext
// expects.
if (Opts.RelativeAddresses)
ModuleOffset.Address += Info->getModulePreferredBase();
return Info->symbolizeFrame(ModuleOffset);
}
void LLVMSymbolizer::flush() {
ObjectForUBPathAndArch.clear();
BinaryForPath.clear();
ObjectPairForPathArch.clear();
Modules.clear();
}
namespace {
// For Path="/path/to/foo" and Basename="foo" assume that debug info is in
// /path/to/foo.dSYM/Contents/Resources/DWARF/foo.
// For Path="/path/to/bar.dSYM" and Basename="foo" assume that debug info is in
// /path/to/bar.dSYM/Contents/Resources/DWARF/foo.
std::string getDarwinDWARFResourceForPath(
const std::string &Path, const std::string &Basename) {
SmallString<16> ResourceName = StringRef(Path);
if (sys::path::extension(Path) != ".dSYM") {
ResourceName += ".dSYM";
}
sys::path::append(ResourceName, "Contents", "Resources", "DWARF");
sys::path::append(ResourceName, Basename);
return ResourceName.str();
}
bool checkFileCRC(StringRef Path, uint32_t CRCHash) {
ErrorOr<std::unique_ptr<MemoryBuffer>> MB =
MemoryBuffer::getFileOrSTDIN(Path);
if (!MB)
return false;
return CRCHash == llvm::crc32(arrayRefFromStringRef(MB.get()->getBuffer()));
}
bool findDebugBinary(const std::string &OrigPath,
const std::string &DebuglinkName, uint32_t CRCHash,
const std::string &FallbackDebugPath,
std::string &Result) {
SmallString<16> OrigDir(OrigPath);
llvm::sys::path::remove_filename(OrigDir);
SmallString<16> DebugPath = OrigDir;
// Try relative/path/to/original_binary/debuglink_name
llvm::sys::path::append(DebugPath, DebuglinkName);
if (checkFileCRC(DebugPath, CRCHash)) {
Result = DebugPath.str();
return true;
}
// Try relative/path/to/original_binary/.debug/debuglink_name
DebugPath = OrigDir;
llvm::sys::path::append(DebugPath, ".debug", DebuglinkName);
if (checkFileCRC(DebugPath, CRCHash)) {
Result = DebugPath.str();
return true;
}
// Make the path absolute so that lookups will go to
// "/usr/lib/debug/full/path/to/debug", not
// "/usr/lib/debug/to/debug"
llvm::sys::fs::make_absolute(OrigDir);
if (!FallbackDebugPath.empty()) {
// Try <FallbackDebugPath>/absolute/path/to/original_binary/debuglink_name
DebugPath = FallbackDebugPath;
} else {
#if defined(__NetBSD__)
// Try /usr/libdata/debug/absolute/path/to/original_binary/debuglink_name
DebugPath = "/usr/libdata/debug";
#else
// Try /usr/lib/debug/absolute/path/to/original_binary/debuglink_name
DebugPath = "/usr/lib/debug";
#endif
}
llvm::sys::path::append(DebugPath, llvm::sys::path::relative_path(OrigDir),
DebuglinkName);
if (checkFileCRC(DebugPath, CRCHash)) {
Result = DebugPath.str();
return true;
}
return false;
}
bool getGNUDebuglinkContents(const ObjectFile *Obj, std::string &DebugName,
uint32_t &CRCHash) {
if (!Obj)
return false;
for (const SectionRef &Section : Obj->sections()) {
StringRef Name;
if (Expected<StringRef> NameOrErr = Section.getName())
Name = *NameOrErr;
else
consumeError(NameOrErr.takeError());
Name = Name.substr(Name.find_first_not_of("._"));
if (Name == "gnu_debuglink") {
Expected<StringRef> ContentsOrErr = Section.getContents();
if (!ContentsOrErr) {
consumeError(ContentsOrErr.takeError());
return false;
}
DataExtractor DE(*ContentsOrErr, Obj->isLittleEndian(), 0);
uint64_t Offset = 0;
if (const char *DebugNameStr = DE.getCStr(&Offset)) {
// 4-byte align the offset.
Offset = (Offset + 3) & ~0x3;
if (DE.isValidOffsetForDataOfSize(Offset, 4)) {
DebugName = DebugNameStr;
CRCHash = DE.getU32(&Offset);
return true;
}
}
break;
}
}
return false;
}
bool darwinDsymMatchesBinary(const MachOObjectFile *DbgObj,
const MachOObjectFile *Obj) {
ArrayRef<uint8_t> dbg_uuid = DbgObj->getUuid();
ArrayRef<uint8_t> bin_uuid = Obj->getUuid();
if (dbg_uuid.empty() || bin_uuid.empty())
return false;
return !memcmp(dbg_uuid.data(), bin_uuid.data(), dbg_uuid.size());
}
template <typename ELFT>
Optional<ArrayRef<uint8_t>> getBuildID(const ELFFile<ELFT> *Obj) {
if (!Obj)
return {};
auto PhdrsOrErr = Obj->program_headers();
if (!PhdrsOrErr) {
consumeError(PhdrsOrErr.takeError());
return {};
}
for (const auto &P : *PhdrsOrErr) {
if (P.p_type != ELF::PT_NOTE)
continue;
Error Err = Error::success();
for (auto N : Obj->notes(P, Err))
if (N.getType() == ELF::NT_GNU_BUILD_ID && N.getName() == ELF::ELF_NOTE_GNU)
return N.getDesc();
}
return {};
}
Optional<ArrayRef<uint8_t>> getBuildID(const ELFObjectFileBase *Obj) {
Optional<ArrayRef<uint8_t>> BuildID;
if (auto *O = dyn_cast<ELFObjectFile<ELF32LE>>(Obj))
BuildID = getBuildID(O->getELFFile());
else if (auto *O = dyn_cast<ELFObjectFile<ELF32BE>>(Obj))
BuildID = getBuildID(O->getELFFile());
else if (auto *O = dyn_cast<ELFObjectFile<ELF64LE>>(Obj))
BuildID = getBuildID(O->getELFFile());
else if (auto *O = dyn_cast<ELFObjectFile<ELF64BE>>(Obj))
BuildID = getBuildID(O->getELFFile());
else
llvm_unreachable("unsupported file format");
return BuildID;
}
bool findDebugBinary(const std::vector<std::string> &DebugFileDirectory,
const ArrayRef<uint8_t> BuildID,
std::string &Result) {
auto getDebugPath = [&](StringRef Directory) {
SmallString<128> Path{Directory};
sys::path::append(Path, ".build-id",
llvm::toHex(BuildID[0], /*LowerCase=*/true),
llvm::toHex(BuildID.slice(1), /*LowerCase=*/true));
Path += ".debug";
return Path;
};
if (DebugFileDirectory.empty()) {
SmallString<128> Path = getDebugPath(
#if defined(__NetBSD__)
// Try /usr/libdata/debug/.build-id/../...
"/usr/libdata/debug"
#else
// Try /usr/lib/debug/.build-id/../...
"/usr/lib/debug"
#endif
);
if (llvm::sys::fs::exists(Path)) {
Result = Path.str();
return true;
}
} else {
for (const auto &Directory : DebugFileDirectory) {
// Try <debug-file-directory>/.build-id/../...
SmallString<128> Path = getDebugPath(Directory);
if (llvm::sys::fs::exists(Path)) {
Result = Path.str();
return true;
}
}
}
return false;
}
} // end anonymous namespace
ObjectFile *LLVMSymbolizer::lookUpDsymFile(const std::string &ExePath,
const MachOObjectFile *MachExeObj, const std::string &ArchName) {
// On Darwin we may find DWARF in separate object file in
// resource directory.
std::vector<std::string> DsymPaths;
StringRef Filename = sys::path::filename(ExePath);
DsymPaths.push_back(getDarwinDWARFResourceForPath(ExePath, Filename));
for (const auto &Path : Opts.DsymHints) {
DsymPaths.push_back(getDarwinDWARFResourceForPath(Path, Filename));
}
for (const auto &Path : DsymPaths) {
auto DbgObjOrErr = getOrCreateObject(Path, ArchName);
if (!DbgObjOrErr) {
// Ignore errors, the file might not exist.
consumeError(DbgObjOrErr.takeError());
continue;
}
ObjectFile *DbgObj = DbgObjOrErr.get();
if (!DbgObj)
continue;
const MachOObjectFile *MachDbgObj = dyn_cast<const MachOObjectFile>(DbgObj);
if (!MachDbgObj)
continue;
if (darwinDsymMatchesBinary(MachDbgObj, MachExeObj))
return DbgObj;
}
return nullptr;
}
ObjectFile *LLVMSymbolizer::lookUpDebuglinkObject(const std::string &Path,
const ObjectFile *Obj,
const std::string &ArchName) {
std::string DebuglinkName;
uint32_t CRCHash;
std::string DebugBinaryPath;
if (!getGNUDebuglinkContents(Obj, DebuglinkName, CRCHash))
return nullptr;
if (!findDebugBinary(Path, DebuglinkName, CRCHash, Opts.FallbackDebugPath,
DebugBinaryPath))
return nullptr;
auto DbgObjOrErr = getOrCreateObject(DebugBinaryPath, ArchName);
if (!DbgObjOrErr) {
// Ignore errors, the file might not exist.
consumeError(DbgObjOrErr.takeError());
return nullptr;
}
return DbgObjOrErr.get();
}
ObjectFile *LLVMSymbolizer::lookUpBuildIDObject(const std::string &Path,
const ELFObjectFileBase *Obj,
const std::string &ArchName) {
auto BuildID = getBuildID(Obj);
if (!BuildID)
return nullptr;
if (BuildID->size() < 2)
return nullptr;
std::string DebugBinaryPath;
if (!findDebugBinary(Opts.DebugFileDirectory, *BuildID, DebugBinaryPath))
return nullptr;
auto DbgObjOrErr = getOrCreateObject(DebugBinaryPath, ArchName);
if (!DbgObjOrErr) {
consumeError(DbgObjOrErr.takeError());
return nullptr;
}
return DbgObjOrErr.get();
}
Expected<LLVMSymbolizer::ObjectPair>
LLVMSymbolizer::getOrCreateObjectPair(const std::string &Path,
const std::string &ArchName) {
auto I = ObjectPairForPathArch.find(std::make_pair(Path, ArchName));
if (I != ObjectPairForPathArch.end())
return I->second;
auto ObjOrErr = getOrCreateObject(Path, ArchName);
if (!ObjOrErr) {
ObjectPairForPathArch.emplace(std::make_pair(Path, ArchName),
ObjectPair(nullptr, nullptr));
return ObjOrErr.takeError();
}
ObjectFile *Obj = ObjOrErr.get();
assert(Obj != nullptr);
ObjectFile *DbgObj = nullptr;
if (auto MachObj = dyn_cast<const MachOObjectFile>(Obj))
DbgObj = lookUpDsymFile(Path, MachObj, ArchName);
else if (auto ELFObj = dyn_cast<const ELFObjectFileBase>(Obj))
DbgObj = lookUpBuildIDObject(Path, ELFObj, ArchName);
if (!DbgObj)
DbgObj = lookUpDebuglinkObject(Path, Obj, ArchName);
if (!DbgObj)
DbgObj = Obj;
ObjectPair Res = std::make_pair(Obj, DbgObj);
ObjectPairForPathArch.emplace(std::make_pair(Path, ArchName), Res);
return Res;
}
Expected<ObjectFile *>
LLVMSymbolizer::getOrCreateObject(const std::string &Path,
const std::string &ArchName) {
Binary *Bin;
auto Pair = BinaryForPath.emplace(Path, OwningBinary<Binary>());
if (!Pair.second) {
Bin = Pair.first->second.getBinary();
} else {
Expected<OwningBinary<Binary>> BinOrErr = createBinary(Path);
if (!BinOrErr)
return BinOrErr.takeError();
Pair.first->second = std::move(BinOrErr.get());
Bin = Pair.first->second.getBinary();
}
if (!Bin)
return static_cast<ObjectFile *>(nullptr);
if (MachOUniversalBinary *UB = dyn_cast_or_null<MachOUniversalBinary>(Bin)) {
auto I = ObjectForUBPathAndArch.find(std::make_pair(Path, ArchName));
if (I != ObjectForUBPathAndArch.end())
return I->second.get();
Expected<std::unique_ptr<ObjectFile>> ObjOrErr =
UB->getMachOObjectForArch(ArchName);
if (!ObjOrErr) {
ObjectForUBPathAndArch.emplace(std::make_pair(Path, ArchName),
std::unique_ptr<ObjectFile>());
return ObjOrErr.takeError();
}
ObjectFile *Res = ObjOrErr->get();
ObjectForUBPathAndArch.emplace(std::make_pair(Path, ArchName),
std::move(ObjOrErr.get()));
return Res;
}
if (Bin->isObject()) {
return cast<ObjectFile>(Bin);
}
return errorCodeToError(object_error::arch_not_found);
}
Expected<SymbolizableModule *>
LLVMSymbolizer::createModuleInfo(const ObjectFile *Obj,
std::unique_ptr<DIContext> Context,
StringRef ModuleName) {
auto InfoOrErr = SymbolizableObjectFile::create(Obj, std::move(Context),
Opts.UntagAddresses);
std::unique_ptr<SymbolizableModule> SymMod;
if (InfoOrErr)
SymMod = std::move(*InfoOrErr);
auto InsertResult =
Modules.insert(std::make_pair(ModuleName, std::move(SymMod)));
assert(InsertResult.second);
if (std::error_code EC = InfoOrErr.getError())
return errorCodeToError(EC);
return InsertResult.first->second.get();
}
Expected<SymbolizableModule *>
LLVMSymbolizer::getOrCreateModuleInfo(const std::string &ModuleName) {
auto I = Modules.find(ModuleName);
if (I != Modules.end())
return I->second.get();
std::string BinaryName = ModuleName;
std::string ArchName = Opts.DefaultArch;
size_t ColonPos = ModuleName.find_last_of(':');
// Verify that substring after colon form a valid arch name.
if (ColonPos != std::string::npos) {
std::string ArchStr = ModuleName.substr(ColonPos + 1);
if (Triple(ArchStr).getArch() != Triple::UnknownArch) {
BinaryName = ModuleName.substr(0, ColonPos);
ArchName = ArchStr;
}
}
auto ObjectsOrErr = getOrCreateObjectPair(BinaryName, ArchName);
if (!ObjectsOrErr) {
// Failed to find valid object file.
Modules.emplace(ModuleName, std::unique_ptr<SymbolizableModule>());
return ObjectsOrErr.takeError();
}
ObjectPair Objects = ObjectsOrErr.get();
std::unique_ptr<DIContext> Context;
// If this is a COFF object containing PDB info, use a PDBContext to
// symbolize. Otherwise, use DWARF.
if (auto CoffObject = dyn_cast<COFFObjectFile>(Objects.first)) {
const codeview::DebugInfo *DebugInfo;
StringRef PDBFileName;
auto EC = CoffObject->getDebugPDBInfo(DebugInfo, PDBFileName);
if (!EC && DebugInfo != nullptr && !PDBFileName.empty()) {
using namespace pdb;
std::unique_ptr<IPDBSession> Session;
if (auto Err = loadDataForEXE(PDB_ReaderType::DIA,
Objects.first->getFileName(), Session)) {
Modules.emplace(ModuleName, std::unique_ptr<SymbolizableModule>());
// Return along the PDB filename to provide more context
return createFileError(PDBFileName, std::move(Err));
}
Context.reset(new PDBContext(*CoffObject, std::move(Session)));
}
}
if (!Context)
Context =
DWARFContext::create(*Objects.second, nullptr,
DWARFContext::defaultErrorHandler, Opts.DWPName);
return createModuleInfo(Objects.first, std::move(Context), ModuleName);
}
namespace {
// Undo these various manglings for Win32 extern "C" functions:
// cdecl - _foo
// stdcall - _foo@12
// fastcall - @foo@12
// vectorcall - foo@@12
// These are all different linkage names for 'foo'.
StringRef demanglePE32ExternCFunc(StringRef SymbolName) {
// Remove any '_' or '@' prefix.
char Front = SymbolName.empty() ? '\0' : SymbolName[0];
if (Front == '_' || Front == '@')
SymbolName = SymbolName.drop_front();
// Remove any '@[0-9]+' suffix.
if (Front != '?') {
size_t AtPos = SymbolName.rfind('@');
if (AtPos != StringRef::npos &&
std::all_of(SymbolName.begin() + AtPos + 1, SymbolName.end(),
[](char C) { return C >= '0' && C <= '9'; })) {
SymbolName = SymbolName.substr(0, AtPos);
}
}
// Remove any ending '@' for vectorcall.
if (SymbolName.endswith("@"))
SymbolName = SymbolName.drop_back();
return SymbolName;
}
} // end anonymous namespace
std::string
LLVMSymbolizer::DemangleName(const std::string &Name,
const SymbolizableModule *DbiModuleDescriptor) {
// We can spoil names of symbols with C linkage, so use an heuristic
// approach to check if the name should be demangled.
if (Name.substr(0, 2) == "_Z") {
int status = 0;
char *DemangledName = itaniumDemangle(Name.c_str(), nullptr, nullptr, &status);
if (status != 0)
return Name;
std::string Result = DemangledName;
free(DemangledName);
return Result;
}
if (!Name.empty() && Name.front() == '?') {
// Only do MSVC C++ demangling on symbols starting with '?'.
int status = 0;
char *DemangledName = microsoftDemangle(
Name.c_str(), nullptr, nullptr, &status,
MSDemangleFlags(MSDF_NoAccessSpecifier | MSDF_NoCallingConvention |
MSDF_NoMemberType | MSDF_NoReturnType));
if (status != 0)
return Name;
std::string Result = DemangledName;
free(DemangledName);
return Result;
}
if (DbiModuleDescriptor && DbiModuleDescriptor->isWin32Module())
return std::string(demanglePE32ExternCFunc(Name));
return Name;
}
} // namespace symbolize
} // namespace llvm