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
PublicsStream(std::unique_ptr<MappedBlockStream> Stream)40 PublicsStream::PublicsStream(std::unique_ptr<MappedBlockStream> Stream)
41 : Stream(std::move(Stream)) {}
42
43 PublicsStream::~PublicsStream() = default;
44
getSymHash() const45 uint32_t PublicsStream::getSymHash() const { return Header->SymHash; }
getThunkTableSection() const46 uint16_t PublicsStream::getThunkTableSection() const {
47 return Header->ISectThunkTable;
48 }
getThunkTableOffset() const49 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.
reload()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