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-exception 6 // 7 //===----------------------------------------------------------------------===// 8 9 #include <unordered_set> 10 11 #include "llvm/Object/ELFObjectFile.h" 12 #include "llvm/Object/MachOUniversal.h" 13 #include "llvm/Object/ObjectFile.h" 14 #include "llvm/Support/DataExtractor.h" 15 #include "llvm/Support/raw_ostream.h" 16 17 #include "llvm/DebugInfo/GSYM/ObjectFileTransformer.h" 18 #include "llvm/DebugInfo/GSYM/GsymCreator.h" 19 20 using namespace llvm; 21 using namespace gsym; 22 23 constexpr uint32_t NT_GNU_BUILD_ID_TAG = 0x03; 24 25 static std::vector<uint8_t> getUUID(const object::ObjectFile &Obj) { 26 // Extract the UUID from the object file 27 std::vector<uint8_t> UUID; 28 if (auto *MachO = dyn_cast<object::MachOObjectFile>(&Obj)) { 29 const ArrayRef<uint8_t> MachUUID = MachO->getUuid(); 30 if (!MachUUID.empty()) 31 UUID.assign(MachUUID.data(), MachUUID.data() + MachUUID.size()); 32 } else if (isa<object::ELFObjectFileBase>(&Obj)) { 33 const StringRef GNUBuildID(".note.gnu.build-id"); 34 for (const object::SectionRef &Sect : Obj.sections()) { 35 Expected<StringRef> SectNameOrErr = Sect.getName(); 36 if (!SectNameOrErr) { 37 consumeError(SectNameOrErr.takeError()); 38 continue; 39 } 40 StringRef SectName(*SectNameOrErr); 41 if (SectName != GNUBuildID) 42 continue; 43 StringRef BuildIDData; 44 Expected<StringRef> E = Sect.getContents(); 45 if (E) 46 BuildIDData = *E; 47 else { 48 consumeError(E.takeError()); 49 continue; 50 } 51 DataExtractor Decoder(BuildIDData, Obj.makeTriple().isLittleEndian(), 8); 52 uint64_t Offset = 0; 53 const uint32_t NameSize = Decoder.getU32(&Offset); 54 const uint32_t PayloadSize = Decoder.getU32(&Offset); 55 const uint32_t PayloadType = Decoder.getU32(&Offset); 56 StringRef Name(Decoder.getFixedLengthString(&Offset, NameSize)); 57 if (Name == "GNU" && PayloadType == NT_GNU_BUILD_ID_TAG) { 58 Offset = alignTo(Offset, 4); 59 StringRef UUIDBytes(Decoder.getBytes(&Offset, PayloadSize)); 60 if (!UUIDBytes.empty()) { 61 auto Ptr = reinterpret_cast<const uint8_t *>(UUIDBytes.data()); 62 UUID.assign(Ptr, Ptr + UUIDBytes.size()); 63 } 64 } 65 } 66 } 67 return UUID; 68 } 69 70 llvm::Error ObjectFileTransformer::convert(const object::ObjectFile &Obj, 71 raw_ostream &Log, 72 GsymCreator &Gsym) { 73 using namespace llvm::object; 74 75 const bool IsMachO = isa<MachOObjectFile>(&Obj); 76 const bool IsELF = isa<ELFObjectFileBase>(&Obj); 77 78 // Read build ID. 79 Gsym.setUUID(getUUID(Obj)); 80 81 // Parse the symbol table. 82 size_t NumBefore = Gsym.getNumFunctionInfos(); 83 for (const object::SymbolRef &Sym : Obj.symbols()) { 84 Expected<SymbolRef::Type> SymType = Sym.getType(); 85 if (!SymType) { 86 consumeError(SymType.takeError()); 87 continue; 88 } 89 Expected<uint64_t> AddrOrErr = Sym.getValue(); 90 if (!AddrOrErr) 91 // TODO: Test this error. 92 return AddrOrErr.takeError(); 93 94 if (SymType.get() != SymbolRef::Type::ST_Function || 95 !Gsym.IsValidTextAddress(*AddrOrErr) || 96 Gsym.hasFunctionInfoForAddress(*AddrOrErr)) 97 continue; 98 // Function size for MachO files will be 0 99 constexpr bool NoCopy = false; 100 const uint64_t size = IsELF ? ELFSymbolRef(Sym).getSize() : 0; 101 Expected<StringRef> Name = Sym.getName(); 102 if (!Name) { 103 logAllUnhandledErrors(Name.takeError(), Log, "ObjectFileTransformer: "); 104 continue; 105 } 106 // Remove the leading '_' character in any symbol names if there is one 107 // for mach-o files. 108 if (IsMachO) 109 Name->consume_front("_"); 110 Gsym.addFunctionInfo( 111 FunctionInfo(*AddrOrErr, size, Gsym.insertString(*Name, NoCopy))); 112 } 113 size_t FunctionsAddedCount = Gsym.getNumFunctionInfos() - NumBefore; 114 Log << "Loaded " << FunctionsAddedCount << " functions from symbol table.\n"; 115 return Error::success(); 116 } 117