121 lines · cpp
1//===- ObjectFileTransformer.cpp --------------------------------*- C++ -*-===//2//3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.4// See https://llvm.org/LICENSE.txt for license information.5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception6//7//===----------------------------------------------------------------------===//8 9#include "llvm/Object/ELFObjectFile.h"10#include "llvm/Object/MachOUniversal.h"11#include "llvm/Object/ObjectFile.h"12#include "llvm/Support/DataExtractor.h"13#include "llvm/Support/raw_ostream.h"14 15#include "llvm/DebugInfo/GSYM/GsymCreator.h"16#include "llvm/DebugInfo/GSYM/ObjectFileTransformer.h"17#include "llvm/DebugInfo/GSYM/OutputAggregator.h"18 19using namespace llvm;20using namespace gsym;21 22constexpr uint32_t NT_GNU_BUILD_ID_TAG = 0x03;23 24static std::vector<uint8_t> getUUID(const object::ObjectFile &Obj) {25 // Extract the UUID from the object file26 std::vector<uint8_t> UUID;27 if (auto *MachO = dyn_cast<object::MachOObjectFile>(&Obj)) {28 const ArrayRef<uint8_t> MachUUID = MachO->getUuid();29 if (!MachUUID.empty())30 UUID.assign(MachUUID.data(), MachUUID.data() + MachUUID.size());31 } else if (isa<object::ELFObjectFileBase>(&Obj)) {32 const StringRef GNUBuildID(".note.gnu.build-id");33 for (const object::SectionRef &Sect : Obj.sections()) {34 Expected<StringRef> SectNameOrErr = Sect.getName();35 if (!SectNameOrErr) {36 consumeError(SectNameOrErr.takeError());37 continue;38 }39 StringRef SectName(*SectNameOrErr);40 if (SectName != GNUBuildID)41 continue;42 StringRef BuildIDData;43 Expected<StringRef> E = Sect.getContents();44 if (E)45 BuildIDData = *E;46 else {47 consumeError(E.takeError());48 continue;49 }50 DataExtractor Decoder(BuildIDData, Obj.makeTriple().isLittleEndian(), 8);51 uint64_t Offset = 0;52 const uint32_t NameSize = Decoder.getU32(&Offset);53 const uint32_t PayloadSize = Decoder.getU32(&Offset);54 const uint32_t PayloadType = Decoder.getU32(&Offset);55 StringRef Name(Decoder.getFixedLengthString(&Offset, NameSize));56 if (Name == "GNU" && PayloadType == NT_GNU_BUILD_ID_TAG) {57 Offset = alignTo(Offset, 4);58 StringRef UUIDBytes(Decoder.getBytes(&Offset, PayloadSize));59 if (!UUIDBytes.empty()) {60 auto Ptr = reinterpret_cast<const uint8_t *>(UUIDBytes.data());61 UUID.assign(Ptr, Ptr + UUIDBytes.size());62 }63 }64 }65 }66 return UUID;67}68 69llvm::Error ObjectFileTransformer::convert(const object::ObjectFile &Obj,70 OutputAggregator &Out,71 GsymCreator &Gsym) {72 using namespace llvm::object;73 74 const bool IsMachO = isa<MachOObjectFile>(&Obj);75 const bool IsELF = isa<ELFObjectFileBase>(&Obj);76 77 // Read build ID.78 Gsym.setUUID(getUUID(Obj));79 80 // Parse the symbol table.81 size_t NumBefore = Gsym.getNumFunctionInfos();82 for (const object::SymbolRef &Sym : Obj.symbols()) {83 Expected<SymbolRef::Type> SymType = Sym.getType();84 if (!SymType) {85 consumeError(SymType.takeError());86 continue;87 }88 Expected<uint64_t> AddrOrErr = Sym.getValue();89 if (!AddrOrErr)90 // TODO: Test this error.91 return AddrOrErr.takeError();92 93 if (SymType.get() != SymbolRef::Type::ST_Function ||94 !Gsym.IsValidTextAddress(*AddrOrErr))95 continue;96 // Function size for MachO files will be 097 constexpr bool NoCopy = false;98 const uint64_t size = IsELF ? ELFSymbolRef(Sym).getSize() : 0;99 Expected<StringRef> Name = Sym.getName();100 if (!Name) {101 if (Out.GetOS())102 logAllUnhandledErrors(Name.takeError(), *Out.GetOS(),103 "ObjectFileTransformer: ");104 else105 consumeError(Name.takeError());106 continue;107 }108 // Remove the leading '_' character in any symbol names if there is one109 // for mach-o files.110 if (IsMachO)111 Name->consume_front("_");112 Gsym.addFunctionInfo(113 FunctionInfo(*AddrOrErr, size, Gsym.insertString(*Name, NoCopy)));114 }115 size_t FunctionsAddedCount = Gsym.getNumFunctionInfos() - NumBefore;116 if (Out.GetOS())117 *Out.GetOS() << "Loaded " << FunctionsAddedCount118 << " functions from symbol table.\n";119 return Error::success();120}121