1//===- GlobalsStream.cpp - PDB Index of Symbols by Name ---------*- 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// The on-disk structores used 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//===----------------------------------------------------------------------===//
20
21#include "llvm/DebugInfo/PDB/Native/GlobalsStream.h"
22
23#include "llvm/DebugInfo/CodeView/RecordName.h"
24#include "llvm/DebugInfo/MSF/MappedBlockStream.h"
25#include "llvm/DebugInfo/PDB/Native/Hash.h"
26#include "llvm/DebugInfo/PDB/Native/RawError.h"
27#include "llvm/DebugInfo/PDB/Native/SymbolStream.h"
28#include "llvm/Support/BinaryStreamReader.h"
29#include "llvm/Support/Error.h"
30
31using namespace llvm;
32using namespace llvm::msf;
33using namespace llvm::pdb;
34
35GlobalsStream::GlobalsStream(std::unique_ptr<MappedBlockStream> Stream)
36 : Stream(std::move(Stream)) {}
37
38GlobalsStream::~GlobalsStream() = default;
39
40Error GlobalsStream::reload() {
41 BinaryStreamReader Reader(*Stream);
42 if (auto E = GlobalsTable.read(Reader))
43 return E;
44 return Error::success();
45}
46
47std::vector<std::pair<uint32_t, codeview::CVSymbol>>
48GlobalsStream::findRecordsByName(StringRef Name,
49 const SymbolStream &Symbols) const {
50 std::vector<std::pair<uint32_t, codeview::CVSymbol>> Result;
51
52 // Hash the name to figure out which bucket this goes into.
53 size_t ExpandedBucketIndex = hashStringV1(Str: Name) % IPHR_HASH;
54 int32_t CompressedBucketIndex = GlobalsTable.BucketMap[ExpandedBucketIndex];
55 if (CompressedBucketIndex == -1)
56 return Result;
57
58 uint32_t LastBucketIndex = GlobalsTable.HashBuckets.size() - 1;
59 uint32_t StartRecordIndex =
60 GlobalsTable.HashBuckets[CompressedBucketIndex] / 12;
61 uint32_t EndRecordIndex = 0;
62 if (LLVM_LIKELY(uint32_t(CompressedBucketIndex) < LastBucketIndex)) {
63 EndRecordIndex = GlobalsTable.HashBuckets[CompressedBucketIndex + 1];
64 } else {
65 // If this is the last bucket, it consists of all hash records until the end
66 // of the HashRecords array.
67 EndRecordIndex = GlobalsTable.HashRecords.size() * 12;
68 }
69
70 EndRecordIndex /= 12;
71
72 assert(EndRecordIndex <= GlobalsTable.HashRecords.size());
73 while (StartRecordIndex < EndRecordIndex) {
74 PSHashRecord PSH = GlobalsTable.HashRecords[StartRecordIndex];
75 uint32_t Off = PSH.Off - 1;
76 codeview::CVSymbol Record = Symbols.readRecord(Offset: Off);
77 if (codeview::getSymbolName(Sym: Record) == Name)
78 Result.push_back(x: std::make_pair(x&: Off, y: std::move(Record)));
79 ++StartRecordIndex;
80 }
81 return Result;
82}
83
84static Error checkHashHdrVersion(const GSIHashHeader *HashHdr) {
85 if (HashHdr->VerHdr != GSIHashHeader::HdrVersion)
86 return make_error<RawError>(
87 Args: raw_error_code::feature_unsupported,
88 Args: "Encountered unsupported globals stream version.");
89
90 return Error::success();
91}
92
93static Error readGSIHashHeader(const GSIHashHeader *&HashHdr,
94 BinaryStreamReader &Reader) {
95 if (Reader.readObject(Dest&: HashHdr))
96 return make_error<RawError>(Args: raw_error_code::corrupt_file,
97 Args: "Stream does not contain a GSIHashHeader.");
98
99 if (HashHdr->VerSignature != GSIHashHeader::HdrSignature)
100 return make_error<RawError>(
101 Args: raw_error_code::feature_unsupported,
102 Args: "GSIHashHeader signature (0xffffffff) not found.");
103
104 return Error::success();
105}
106
107static Error readGSIHashRecords(FixedStreamArray<PSHashRecord> &HashRecords,
108 const GSIHashHeader *HashHdr,
109 BinaryStreamReader &Reader) {
110 if (auto EC = checkHashHdrVersion(HashHdr))
111 return EC;
112
113 // HashHdr->HrSize specifies the number of bytes of PSHashRecords we have.
114 // Verify that we can read them all.
115 if (HashHdr->HrSize % sizeof(PSHashRecord))
116 return make_error<RawError>(Args: raw_error_code::corrupt_file,
117 Args: "Invalid HR array size.");
118 uint32_t NumHashRecords = HashHdr->HrSize / sizeof(PSHashRecord);
119 if (auto EC = Reader.readArray(Array&: HashRecords, NumItems: NumHashRecords))
120 return joinErrors(E1: std::move(EC),
121 E2: make_error<RawError>(Args: raw_error_code::corrupt_file,
122 Args: "Error reading hash records."));
123
124 return Error::success();
125}
126
127static Error
128readGSIHashBuckets(FixedStreamArray<support::ulittle32_t> &HashBuckets,
129 FixedStreamArray<support::ulittle32_t> &HashBitmap,
130 const GSIHashHeader *HashHdr,
131 MutableArrayRef<int32_t> BucketMap,
132 BinaryStreamReader &Reader) {
133 if (auto EC = checkHashHdrVersion(HashHdr))
134 return EC;
135
136 // Before the actual hash buckets, there is a bitmap of length determined by
137 // IPHR_HASH.
138 size_t BitmapSizeInBits = alignTo(Value: IPHR_HASH + 1, Align: 32);
139 uint32_t NumBitmapEntries = BitmapSizeInBits / 32;
140 if (auto EC = Reader.readArray(Array&: HashBitmap, NumItems: NumBitmapEntries))
141 return joinErrors(E1: std::move(EC),
142 E2: make_error<RawError>(Args: raw_error_code::corrupt_file,
143 Args: "Could not read a bitmap."));
144 uint32_t CompressedBucketIdx = 0;
145 for (uint32_t I = 0; I <= IPHR_HASH; ++I) {
146 uint8_t WordIdx = I / 32;
147 uint8_t BitIdx = I % 32;
148 bool IsSet = HashBitmap[WordIdx] & (1U << BitIdx);
149 if (IsSet) {
150 BucketMap[I] = CompressedBucketIdx++;
151 } else {
152 BucketMap[I] = -1;
153 }
154 }
155
156 uint32_t NumBuckets = 0;
157 for (uint32_t B : HashBitmap)
158 NumBuckets += llvm::popcount(Value: B);
159
160 // Hash buckets follow.
161 if (auto EC = Reader.readArray(Array&: HashBuckets, NumItems: NumBuckets))
162 return joinErrors(E1: std::move(EC),
163 E2: make_error<RawError>(Args: raw_error_code::corrupt_file,
164 Args: "Hash buckets corrupted."));
165
166 return Error::success();
167}
168
169Error GSIHashTable::read(BinaryStreamReader &Reader) {
170 if (auto EC = readGSIHashHeader(HashHdr, Reader))
171 return EC;
172 if (auto EC = readGSIHashRecords(HashRecords, HashHdr, Reader))
173 return EC;
174 if (HashHdr->HrSize > 0)
175 if (auto EC = readGSIHashBuckets(HashBuckets, HashBitmap, HashHdr,
176 BucketMap, Reader))
177 return EC;
178 return Error::success();
179}
180