1 //===- PublicsStream.cpp - PDB Public Symbol Stream -----------------------===// 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 // The data structures defined in this file are based on the reference 10 // implementation which is available at 11 // https://github.com/Microsoft/microsoft-pdb/blob/master/PDB/dbi/gsi.h 12 // 13 // When you are reading the reference source code, you'd find the 14 // information below useful. 15 // 16 // - ppdb1->m_fMinimalDbgInfo seems to be always true. 17 // - SMALLBUCKETS macro is defined. 18 // 19 // The reference doesn't compile, so I learned just by reading code. 20 // It's not guaranteed to be correct. 21 // 22 //===----------------------------------------------------------------------===// 23 24 #include "llvm/DebugInfo/PDB/Native/PublicsStream.h" 25 #include "llvm/ADT/iterator_range.h" 26 #include "llvm/DebugInfo/CodeView/SymbolRecord.h" 27 #include "llvm/DebugInfo/MSF/MappedBlockStream.h" 28 #include "llvm/DebugInfo/PDB/Native/RawError.h" 29 #include "llvm/Support/BinaryStreamReader.h" 30 #include "llvm/Support/Endian.h" 31 #include "llvm/Support/Error.h" 32 #include <algorithm> 33 #include <cstdint> 34 35 using namespace llvm; 36 using namespace llvm::msf; 37 using namespace llvm::support; 38 using namespace llvm::pdb; 39 40 PublicsStream::PublicsStream(std::unique_ptr<MappedBlockStream> Stream) 41 : Stream(std::move(Stream)) {} 42 43 PublicsStream::~PublicsStream() = default; 44 45 uint32_t PublicsStream::getSymHash() const { return Header->SymHash; } 46 uint16_t PublicsStream::getThunkTableSection() const { 47 return Header->ISectThunkTable; 48 } 49 uint32_t PublicsStream::getThunkTableOffset() const { 50 return Header->OffThunkTable; 51 } 52 53 // Publics stream contains fixed-size headers and a serialized hash table. 54 // This implementation is not complete yet. It reads till the end of the 55 // stream so that we verify the stream is at least not corrupted. However, 56 // we skip over the hash table which we believe contains information about 57 // public symbols. 58 Error PublicsStream::reload() { 59 BinaryStreamReader Reader(*Stream); 60 61 // Check stream size. 62 if (Reader.bytesRemaining() < 63 sizeof(PublicsStreamHeader) + sizeof(GSIHashHeader)) 64 return make_error<RawError>(raw_error_code::corrupt_file, 65 "Publics Stream does not contain a header."); 66 67 // Read PSGSIHDR struct. 68 if (Reader.readObject(Header)) 69 return make_error<RawError>(raw_error_code::corrupt_file, 70 "Publics Stream does not contain a header."); 71 72 // Read the hash table. 73 if (auto E = PublicsTable.read(Reader)) 74 return E; 75 76 // Something called "address map" follows. 77 uint32_t NumAddressMapEntries = Header->AddrMap / sizeof(uint32_t); 78 if (auto EC = Reader.readArray(AddressMap, NumAddressMapEntries)) 79 return joinErrors(std::move(EC), 80 make_error<RawError>(raw_error_code::corrupt_file, 81 "Could not read an address map.")); 82 83 // Something called "thunk map" follows. 84 if (auto EC = Reader.readArray(ThunkMap, Header->NumThunks)) 85 return joinErrors(std::move(EC), 86 make_error<RawError>(raw_error_code::corrupt_file, 87 "Could not read a thunk map.")); 88 89 // Something called "section map" follows. 90 if (Reader.bytesRemaining() > 0) { 91 if (auto EC = Reader.readArray(SectionOffsets, Header->NumSections)) 92 return joinErrors(std::move(EC), 93 make_error<RawError>(raw_error_code::corrupt_file, 94 "Could not read a section map.")); 95 } 96 97 if (Reader.bytesRemaining() > 0) 98 return make_error<RawError>(raw_error_code::corrupt_file, 99 "Corrupted publics stream."); 100 return Error::success(); 101 } 102