1 //===- PDBStringTableBuilder.cpp - PDB String Table -------------*- C++ -*-===//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 #include "llvm/DebugInfo/PDB/Native/PDBStringTableBuilder.h"
12 #include "llvm/ADT/ArrayRef.h"
13 #include "llvm/DebugInfo/PDB/Native/Hash.h"
14 #include "llvm/DebugInfo/PDB/Native/RawTypes.h"
15 #include "llvm/Support/BinaryStreamWriter.h"
16 #include "llvm/Support/Endian.h"
21 using namespace llvm::msf;
22 using namespace llvm::support;
23 using namespace llvm::support::endian;
24 using namespace llvm::pdb;
26 StringTableHashTraits::StringTableHashTraits(PDBStringTableBuilder &Table)
29 uint32_t StringTableHashTraits::hashLookupKey(StringRef S) const {
30 return Table->getIdForString(S);
33 StringRef StringTableHashTraits::storageKeyToLookupKey(uint32_t Offset) const {
34 return Table->getStringForId(Offset);
37 uint32_t StringTableHashTraits::lookupKeyToStorageKey(StringRef S) {
38 return Table->insert(S);
41 uint32_t PDBStringTableBuilder::insert(StringRef S) {
42 return Strings.insert(S);
45 uint32_t PDBStringTableBuilder::getIdForString(StringRef S) const {
46 return Strings.getIdForString(S);
49 StringRef PDBStringTableBuilder::getStringForId(uint32_t Id) const {
50 return Strings.getStringForId(Id);
53 // This is a precomputed list of Buckets given the specified number of
54 // strings. Matching the reference algorithm exactly is not strictly
55 // necessary for correctness, but it helps when comparing LLD's PDBs with
56 // Microsoft's PDBs so as to eliminate superfluous differences.
57 static std::map<uint32_t, uint32_t> StringsToBuckets = {
100 {45405522, 90811043},
101 {68108283, 136216565},
102 {102162424, 204324848},
103 {153243637, 306487273},
104 {229865455, 459730910},
105 {344798183, 689596366},
106 {517197275, 1034394550},
107 {775795913, 1551591826}};
109 static uint32_t computeBucketCount(uint32_t NumStrings) {
110 auto Entry = StringsToBuckets.lower_bound(NumStrings);
111 assert(Entry != StringsToBuckets.end());
112 return Entry->second;
115 uint32_t PDBStringTableBuilder::calculateHashTableSize() const {
116 uint32_t Size = sizeof(uint32_t); // Hash table begins with 4-byte size field.
117 Size += sizeof(uint32_t) * computeBucketCount(Strings.size());
122 uint32_t PDBStringTableBuilder::calculateSerializedSize() const {
124 Size += sizeof(PDBStringTableHeader);
125 Size += Strings.calculateSerializedSize();
126 Size += calculateHashTableSize();
127 Size += sizeof(uint32_t); // The /names stream ends with the string count.
131 void PDBStringTableBuilder::setStrings(
132 const codeview::DebugStringTableSubsection &Strings) {
133 this->Strings = Strings;
136 Error PDBStringTableBuilder::writeHeader(BinaryStreamWriter &Writer) const {
138 PDBStringTableHeader H;
139 H.Signature = PDBStringTableSignature;
141 H.ByteSize = Strings.calculateSerializedSize();
142 if (auto EC = Writer.writeObject(H))
144 assert(Writer.bytesRemaining() == 0);
145 return Error::success();
148 Error PDBStringTableBuilder::writeStrings(BinaryStreamWriter &Writer) const {
149 if (auto EC = Strings.commit(Writer))
152 assert(Writer.bytesRemaining() == 0);
153 return Error::success();
156 Error PDBStringTableBuilder::writeHashTable(BinaryStreamWriter &Writer) const {
157 // Write a hash table.
158 uint32_t BucketCount = computeBucketCount(Strings.size());
159 if (auto EC = Writer.writeInteger(BucketCount))
161 std::vector<ulittle32_t> Buckets(BucketCount);
163 for (auto &Pair : Strings) {
164 StringRef S = Pair.getKey();
165 uint32_t Offset = Pair.getValue();
166 uint32_t Hash = hashStringV1(S);
168 for (uint32_t I = 0; I != BucketCount; ++I) {
169 uint32_t Slot = (Hash + I) % BucketCount;
170 if (Buckets[Slot] != 0)
172 Buckets[Slot] = Offset;
177 if (auto EC = Writer.writeArray(ArrayRef<ulittle32_t>(Buckets)))
180 assert(Writer.bytesRemaining() == 0);
181 return Error::success();
184 Error PDBStringTableBuilder::writeEpilogue(BinaryStreamWriter &Writer) const {
185 if (auto EC = Writer.writeInteger<uint32_t>(Strings.size()))
187 assert(Writer.bytesRemaining() == 0);
188 return Error::success();
191 Error PDBStringTableBuilder::commit(BinaryStreamWriter &Writer) const {
192 BinaryStreamWriter SectionWriter;
194 std::tie(SectionWriter, Writer) = Writer.split(sizeof(PDBStringTableHeader));
195 if (auto EC = writeHeader(SectionWriter))
198 std::tie(SectionWriter, Writer) =
199 Writer.split(Strings.calculateSerializedSize());
200 if (auto EC = writeStrings(SectionWriter))
203 std::tie(SectionWriter, Writer) = Writer.split(calculateHashTableSize());
204 if (auto EC = writeHashTable(SectionWriter))
207 std::tie(SectionWriter, Writer) = Writer.split(sizeof(uint32_t));
208 if (auto EC = writeEpilogue(SectionWriter))
211 return Error::success();