1 //===- NamedStreamMap.cpp - PDB Named Stream Map --------------------------===//
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/NamedStreamMap.h"
10 #include "llvm/ADT/StringMap.h"
11 #include "llvm/ADT/StringRef.h"
12 #include "llvm/DebugInfo/PDB/Native/Hash.h"
13 #include "llvm/DebugInfo/PDB/Native/HashTable.h"
14 #include "llvm/DebugInfo/PDB/Native/RawError.h"
15 #include "llvm/Support/BinaryStreamReader.h"
16 #include "llvm/Support/BinaryStreamWriter.h"
17 #include "llvm/Support/Endian.h"
18 #include "llvm/Support/Error.h"
19 #include <algorithm>
20 #include <cassert>
21 #include <cstdint>
22 
23 using namespace llvm;
24 using namespace llvm::pdb;
25 
26 NamedStreamMapTraits::NamedStreamMapTraits(NamedStreamMap &NS) : NS(&NS) {}
27 
28 uint16_t NamedStreamMapTraits::hashLookupKey(StringRef S) const {
29   // In the reference implementation, this uses
30   // HASH Hasher<ULONG*, USHORT*>::hashPbCb(PB pb, size_t cb, ULONG ulMod).
31   // Here, the type HASH is a typedef of unsigned short.
32   // ** It is not a bug that we truncate the result of hashStringV1, in fact
33   //    it is a bug if we do not! **
34   // See NMTNI::hash() in the reference implementation.
35   return static_cast<uint16_t>(hashStringV1(S));
36 }
37 
38 StringRef NamedStreamMapTraits::storageKeyToLookupKey(uint32_t Offset) const {
39   return NS->getString(Offset);
40 }
41 
42 uint32_t NamedStreamMapTraits::lookupKeyToStorageKey(StringRef S) {
43   return NS->appendStringData(S);
44 }
45 
46 NamedStreamMap::NamedStreamMap() : HashTraits(*this), OffsetIndexMap(1) {}
47 
48 Error NamedStreamMap::load(BinaryStreamReader &Stream) {
49   uint32_t StringBufferSize;
50   if (auto EC = Stream.readInteger(StringBufferSize))
51     return joinErrors(std::move(EC),
52                       make_error<RawError>(raw_error_code::corrupt_file,
53                                            "Expected string buffer size"));
54 
55   StringRef Buffer;
56   if (auto EC = Stream.readFixedString(Buffer, StringBufferSize))
57     return EC;
58   NamesBuffer.assign(Buffer.begin(), Buffer.end());
59 
60   return OffsetIndexMap.load(Stream);
61 }
62 
63 Error NamedStreamMap::commit(BinaryStreamWriter &Writer) const {
64   // The first field is the number of bytes of string data.
65   if (auto EC = Writer.writeInteger<uint32_t>(NamesBuffer.size()))
66     return EC;
67 
68   // Then the actual string data.
69   StringRef Data(NamesBuffer.data(), NamesBuffer.size());
70   if (auto EC = Writer.writeFixedString(Data))
71     return EC;
72 
73   // And finally the Offset Index map.
74   if (auto EC = OffsetIndexMap.commit(Writer))
75     return EC;
76 
77   return Error::success();
78 }
79 
80 uint32_t NamedStreamMap::calculateSerializedLength() const {
81   return sizeof(uint32_t)                              // String data size
82          + NamesBuffer.size()                          // String data
83          + OffsetIndexMap.calculateSerializedLength(); // Offset Index Map
84 }
85 
86 uint32_t NamedStreamMap::size() const { return OffsetIndexMap.size(); }
87 
88 StringRef NamedStreamMap::getString(uint32_t Offset) const {
89   assert(NamesBuffer.size() > Offset);
90   return StringRef(NamesBuffer.data() + Offset);
91 }
92 
93 uint32_t NamedStreamMap::hashString(uint32_t Offset) const {
94   return hashStringV1(getString(Offset));
95 }
96 
97 bool NamedStreamMap::get(StringRef Stream, uint32_t &StreamNo) const {
98   auto Iter = OffsetIndexMap.find_as(Stream, HashTraits);
99   if (Iter == OffsetIndexMap.end())
100     return false;
101   StreamNo = (*Iter).second;
102   return true;
103 }
104 
105 StringMap<uint32_t> NamedStreamMap::entries() const {
106   StringMap<uint32_t> Result;
107   for (const auto &Entry : OffsetIndexMap) {
108     StringRef Stream(NamesBuffer.data() + Entry.first);
109     Result.try_emplace(Stream, Entry.second);
110   }
111   return Result;
112 }
113 
114 uint32_t NamedStreamMap::appendStringData(StringRef S) {
115   uint32_t Offset = NamesBuffer.size();
116   llvm::append_range(NamesBuffer, S);
117   NamesBuffer.push_back('\0');
118   return Offset;
119 }
120 
121 void NamedStreamMap::set(StringRef Stream, uint32_t StreamNo) {
122   OffsetIndexMap.set_as(Stream, support::ulittle32_t(StreamNo), HashTraits);
123 }
124