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/DebugInfo/MSF/MappedBlockStream.h"
26#include "llvm/DebugInfo/PDB/Native/RawError.h"
27#include "llvm/DebugInfo/PDB/Native/RawTypes.h"
28#include "llvm/Support/BinaryStreamReader.h"
29#include "llvm/Support/Error.h"
30#include <cstdint>
31
32using namespace llvm;
33using namespace llvm::msf;
34using namespace llvm::support;
35using namespace llvm::pdb;
36
37PublicsStream::PublicsStream(std::unique_ptr<MappedBlockStream> Stream)
38 : Stream(std::move(Stream)) {}
39
40PublicsStream::~PublicsStream() = default;
41
42uint32_t PublicsStream::getSymHash() const { return Header->SymHash; }
43uint16_t PublicsStream::getThunkTableSection() const {
44 return Header->ISectThunkTable;
45}
46uint32_t PublicsStream::getThunkTableOffset() const {
47 return Header->OffThunkTable;
48}
49
50// Publics stream contains fixed-size headers and a serialized hash table.
51// This implementation is not complete yet. It reads till the end of the
52// stream so that we verify the stream is at least not corrupted. However,
53// we skip over the hash table which we believe contains information about
54// public symbols.
55Error PublicsStream::reload() {
56 BinaryStreamReader Reader(*Stream);
57
58 // Check stream size.
59 if (Reader.bytesRemaining() <
60 sizeof(PublicsStreamHeader) + sizeof(GSIHashHeader))
61 return make_error<RawError>(Args: raw_error_code::corrupt_file,
62 Args: "Publics Stream does not contain a header.");
63
64 // Read PSGSIHDR struct.
65 if (Reader.readObject(Dest&: Header))
66 return make_error<RawError>(Args: raw_error_code::corrupt_file,
67 Args: "Publics Stream does not contain a header.");
68
69 // Read the hash table.
70 if (auto E = PublicsTable.read(Reader))
71 return E;
72
73 // Something called "address map" follows.
74 uint32_t NumAddressMapEntries = Header->AddrMap / sizeof(uint32_t);
75 if (auto EC = Reader.readArray(Array&: AddressMap, NumItems: NumAddressMapEntries))
76 return joinErrors(E1: std::move(EC),
77 E2: make_error<RawError>(Args: raw_error_code::corrupt_file,
78 Args: "Could not read an address map."));
79
80 // Something called "thunk map" follows.
81 if (auto EC = Reader.readArray(Array&: ThunkMap, NumItems: Header->NumThunks))
82 return joinErrors(E1: std::move(EC),
83 E2: make_error<RawError>(Args: raw_error_code::corrupt_file,
84 Args: "Could not read a thunk map."));
85
86 // Something called "section map" follows.
87 if (Reader.bytesRemaining() > 0) {
88 if (auto EC = Reader.readArray(Array&: SectionOffsets, NumItems: Header->NumSections))
89 return joinErrors(E1: std::move(EC),
90 E2: make_error<RawError>(Args: raw_error_code::corrupt_file,
91 Args: "Could not read a section map."));
92 }
93
94 if (Reader.bytesRemaining() > 0)
95 return make_error<RawError>(Args: raw_error_code::corrupt_file,
96 Args: "Corrupted publics stream.");
97 return Error::success();
98}
99