1//===- PDBStringTable.cpp - PDB String Table ---------------------*- 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 "llvm/DebugInfo/PDB/Native/PDBStringTable.h"
10
11#include "llvm/DebugInfo/PDB/Native/Hash.h"
12#include "llvm/DebugInfo/PDB/Native/RawError.h"
13#include "llvm/DebugInfo/PDB/Native/RawTypes.h"
14#include "llvm/Support/BinaryStreamReader.h"
15#include "llvm/Support/Endian.h"
16
17using namespace llvm;
18using namespace llvm::support;
19using namespace llvm::pdb;
20
21uint32_t PDBStringTable::getByteSize() const { return Header->ByteSize; }
22uint32_t PDBStringTable::getNameCount() const { return NameCount; }
23uint32_t PDBStringTable::getHashVersion() const { return Header->HashVersion; }
24uint32_t PDBStringTable::getSignature() const { return Header->Signature; }
25
26Error PDBStringTable::readHeader(BinaryStreamReader &Reader) {
27  if (auto EC = Reader.readObject(Header))
28    return EC;
29
30  if (Header->Signature != PDBStringTableSignature)
31    return make_error<RawError>(raw_error_code::corrupt_file,
32                                "Invalid hash table signature");
33  if (Header->HashVersion != 1 && Header->HashVersion != 2)
34    return make_error<RawError>(raw_error_code::corrupt_file,
35                                "Unsupported hash version");
36
37  assert(Reader.bytesRemaining() == 0);
38  return Error::success();
39}
40
41Error PDBStringTable::readStrings(BinaryStreamReader &Reader) {
42  BinaryStreamRef Stream;
43  if (auto EC = Reader.readStreamRef(Stream))
44    return EC;
45
46  if (auto EC = Strings.initialize(Stream)) {
47    return joinErrors(std::move(EC),
48                      make_error<RawError>(raw_error_code::corrupt_file,
49                                           "Invalid hash table byte length"));
50  }
51
52  assert(Reader.bytesRemaining() == 0);
53  return Error::success();
54}
55
56const codeview::DebugStringTableSubsectionRef &
57PDBStringTable::getStringTable() const {
58  return Strings;
59}
60
61Error PDBStringTable::readHashTable(BinaryStreamReader &Reader) {
62  const support::ulittle32_t *HashCount;
63  if (auto EC = Reader.readObject(HashCount))
64    return EC;
65
66  if (auto EC = Reader.readArray(IDs, *HashCount)) {
67    return joinErrors(std::move(EC),
68                      make_error<RawError>(raw_error_code::corrupt_file,
69                                           "Could not read bucket array"));
70  }
71
72  return Error::success();
73}
74
75Error PDBStringTable::readEpilogue(BinaryStreamReader &Reader) {
76  if (auto EC = Reader.readInteger(NameCount))
77    return EC;
78
79  assert(Reader.bytesRemaining() == 0);
80  return Error::success();
81}
82
83Error PDBStringTable::reload(BinaryStreamReader &Reader) {
84
85  BinaryStreamReader SectionReader;
86
87  std::tie(SectionReader, Reader) = Reader.split(sizeof(PDBStringTableHeader));
88  if (auto EC = readHeader(SectionReader))
89    return EC;
90
91  std::tie(SectionReader, Reader) = Reader.split(Header->ByteSize);
92  if (auto EC = readStrings(SectionReader))
93    return EC;
94
95  // We don't know how long the hash table is until we parse it, so let the
96  // function responsible for doing that figure it out.
97  if (auto EC = readHashTable(Reader))
98    return EC;
99
100  std::tie(SectionReader, Reader) = Reader.split(sizeof(uint32_t));
101  if (auto EC = readEpilogue(SectionReader))
102    return EC;
103
104  assert(Reader.bytesRemaining() == 0);
105  return Error::success();
106}
107
108Expected<StringRef> PDBStringTable::getStringForID(uint32_t ID) const {
109  return Strings.getString(ID);
110}
111
112Expected<uint32_t> PDBStringTable::getIDForString(StringRef Str) const {
113  uint32_t Hash =
114      (Header->HashVersion == 1) ? hashStringV1(Str) : hashStringV2(Str);
115  size_t Count = IDs.size();
116  uint32_t Start = Hash % Count;
117  for (size_t I = 0; I < Count; ++I) {
118    // The hash is just a starting point for the search, but if it
119    // doesn't work we should find the string no matter what, because
120    // we iterate the entire array.
121    uint32_t Index = (Start + I) % Count;
122
123    // If we find 0, it means the item isn't in the hash table.
124    uint32_t ID = IDs[Index];
125    if (ID == 0)
126      return make_error<RawError>(raw_error_code::no_entry);
127    auto ExpectedStr = getStringForID(ID);
128    if (!ExpectedStr)
129      return ExpectedStr.takeError();
130
131    if (*ExpectedStr == Str)
132      return ID;
133  }
134  return make_error<RawError>(raw_error_code::no_entry);
135}
136
137FixedStreamArray<support::ulittle32_t> PDBStringTable::name_ids() const {
138  return IDs;
139}
140