1 //===- PublicsStream.cpp - PDB Public Symbol Stream -----------------------===//
2 //
3 // The LLVM Compiler Infrastructure
4 //
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
7 //
8 //===----------------------------------------------------------------------===//
9 //
10 // The data structures defined in this file are based on the reference
11 // implementation which is available at
12 // https://github.com/Microsoft/microsoft-pdb/blob/master/PDB/dbi/gsi.h
13 //
14 // When you are reading the reference source code, you'd find the
15 // information below useful.
16 //
17 // - ppdb1->m_fMinimalDbgInfo seems to be always true.
18 // - SMALLBUCKETS macro is defined.
19 //
20 // The reference doesn't compile, so I learned just by reading code.
21 // It's not guaranteed to be correct.
22 //
23 //===----------------------------------------------------------------------===//
24
25 #include "llvm/DebugInfo/PDB/Native/PublicsStream.h"
26 #include "llvm/ADT/iterator_range.h"
27 #include "llvm/DebugInfo/CodeView/SymbolRecord.h"
28 #include "llvm/DebugInfo/MSF/MappedBlockStream.h"
29 #include "llvm/DebugInfo/PDB/Native/RawError.h"
30 #include "llvm/Support/BinaryStreamReader.h"
31 #include "llvm/Support/Endian.h"
32 #include "llvm/Support/Error.h"
33 #include <algorithm>
34 #include <cstdint>
35
36 using namespace llvm;
37 using namespace llvm::msf;
38 using namespace llvm::support;
39 using namespace llvm::pdb;
40
PublicsStream(std::unique_ptr<MappedBlockStream> Stream)41 PublicsStream::PublicsStream(std::unique_ptr<MappedBlockStream> Stream)
42 : Stream(std::move(Stream)) {}
43
44 PublicsStream::~PublicsStream() = default;
45
getSymHash() const46 uint32_t PublicsStream::getSymHash() const { return Header->SymHash; }
getThunkTableSection() const47 uint16_t PublicsStream::getThunkTableSection() const {
48 return Header->ISectThunkTable;
49 }
getThunkTableOffset() const50 uint32_t PublicsStream::getThunkTableOffset() const {
51 return Header->OffThunkTable;
52 }
53
54 // Publics stream contains fixed-size headers and a serialized hash table.
55 // This implementation is not complete yet. It reads till the end of the
56 // stream so that we verify the stream is at least not corrupted. However,
57 // we skip over the hash table which we believe contains information about
58 // public symbols.
reload()59 Error PublicsStream::reload() {
60 BinaryStreamReader Reader(*Stream);
61
62 // Check stream size.
63 if (Reader.bytesRemaining() <
64 sizeof(PublicsStreamHeader) + sizeof(GSIHashHeader))
65 return make_error<RawError>(raw_error_code::corrupt_file,
66 "Publics Stream does not contain a header.");
67
68 // Read PSGSIHDR struct.
69 if (Reader.readObject(Header))
70 return make_error<RawError>(raw_error_code::corrupt_file,
71 "Publics Stream does not contain a header.");
72
73 // Read the hash table.
74 if (auto E = PublicsTable.read(Reader))
75 return E;
76
77 // Something called "address map" follows.
78 uint32_t NumAddressMapEntries = Header->AddrMap / sizeof(uint32_t);
79 if (auto EC = Reader.readArray(AddressMap, NumAddressMapEntries))
80 return joinErrors(std::move(EC),
81 make_error<RawError>(raw_error_code::corrupt_file,
82 "Could not read an address map."));
83
84 // Something called "thunk map" follows.
85 if (auto EC = Reader.readArray(ThunkMap, Header->NumThunks))
86 return joinErrors(std::move(EC),
87 make_error<RawError>(raw_error_code::corrupt_file,
88 "Could not read a thunk map."));
89
90 // Something called "section map" follows.
91 if (Reader.bytesRemaining() > 0) {
92 if (auto EC = Reader.readArray(SectionOffsets, Header->NumSections))
93 return joinErrors(std::move(EC),
94 make_error<RawError>(raw_error_code::corrupt_file,
95 "Could not read a section map."));
96 }
97
98 if (Reader.bytesRemaining() > 0)
99 return make_error<RawError>(raw_error_code::corrupt_file,
100 "Corrupted publics stream.");
101 return Error::success();
102 }
103