1 //===- TpiHashing.cpp -----------------------------------------------------===//
2 //
3 // The LLVM Compiler Infrastructure
4 //
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
7 //
8 //===----------------------------------------------------------------------===//
9
10 #include "llvm/DebugInfo/PDB/Native/TpiHashing.h"
11
12 #include "llvm/DebugInfo/CodeView/TypeDeserializer.h"
13 #include "llvm/DebugInfo/PDB/Native/Hash.h"
14 #include "llvm/Support/JamCRC.h"
15
16 using namespace llvm;
17 using namespace llvm::codeview;
18 using namespace llvm::pdb;
19
20 // Corresponds to `fUDTAnon`.
isAnonymous(StringRef Name)21 static bool isAnonymous(StringRef Name) {
22 return Name == "<unnamed-tag>" || Name == "__unnamed" ||
23 Name.endswith("::<unnamed-tag>") || Name.endswith("::__unnamed");
24 }
25
26 // Computes the hash for a user-defined type record. This could be a struct,
27 // class, union, or enum.
getHashForUdt(const TagRecord & Rec,ArrayRef<uint8_t> FullRecord)28 static uint32_t getHashForUdt(const TagRecord &Rec,
29 ArrayRef<uint8_t> FullRecord) {
30 ClassOptions Opts = Rec.getOptions();
31 bool ForwardRef = bool(Opts & ClassOptions::ForwardReference);
32 bool Scoped = bool(Opts & ClassOptions::Scoped);
33 bool HasUniqueName = bool(Opts & ClassOptions::HasUniqueName);
34 bool IsAnon = HasUniqueName && isAnonymous(Rec.getName());
35
36 if (!ForwardRef && !Scoped && !IsAnon)
37 return hashStringV1(Rec.getName());
38 if (!ForwardRef && HasUniqueName && !IsAnon)
39 return hashStringV1(Rec.getUniqueName());
40 return hashBufferV8(FullRecord);
41 }
42
43 template <typename T>
getHashForUdt(const CVType & Rec)44 static Expected<uint32_t> getHashForUdt(const CVType &Rec) {
45 T Deserialized;
46 if (auto E = TypeDeserializer::deserializeAs(const_cast<CVType &>(Rec),
47 Deserialized))
48 return std::move(E);
49 return getHashForUdt(Deserialized, Rec.data());
50 }
51
52 template <typename T>
getTagRecordHashForUdt(const CVType & Rec)53 static Expected<TagRecordHash> getTagRecordHashForUdt(const CVType &Rec) {
54 T Deserialized;
55 if (auto E = TypeDeserializer::deserializeAs(const_cast<CVType &>(Rec),
56 Deserialized))
57 return std::move(E);
58
59 ClassOptions Opts = Deserialized.getOptions();
60
61 bool ForwardRef = bool(Opts & ClassOptions::ForwardReference);
62
63 uint32_t ThisRecordHash = getHashForUdt(Deserialized, Rec.data());
64
65 // If we don't have a forward ref we can't compute the hash of it from the
66 // full record because it requires hashing the entire buffer.
67 if (!ForwardRef)
68 return TagRecordHash{std::move(Deserialized), ThisRecordHash, 0};
69
70 bool Scoped = bool(Opts & ClassOptions::Scoped);
71
72 StringRef NameToHash =
73 Scoped ? Deserialized.getUniqueName() : Deserialized.getName();
74 uint32_t FullHash = hashStringV1(NameToHash);
75 return TagRecordHash{std::move(Deserialized), FullHash, ThisRecordHash};
76 }
77
78 template <typename T>
getSourceLineHash(const CVType & Rec)79 static Expected<uint32_t> getSourceLineHash(const CVType &Rec) {
80 T Deserialized;
81 if (auto E = TypeDeserializer::deserializeAs(const_cast<CVType &>(Rec),
82 Deserialized))
83 return std::move(E);
84 char Buf[4];
85 support::endian::write32le(Buf, Deserialized.getUDT().getIndex());
86 return hashStringV1(StringRef(Buf, 4));
87 }
88
hashTagRecord(const codeview::CVType & Type)89 Expected<TagRecordHash> llvm::pdb::hashTagRecord(const codeview::CVType &Type) {
90 switch (Type.kind()) {
91 case LF_CLASS:
92 case LF_STRUCTURE:
93 case LF_INTERFACE:
94 return getTagRecordHashForUdt<ClassRecord>(Type);
95 case LF_UNION:
96 return getTagRecordHashForUdt<UnionRecord>(Type);
97 case LF_ENUM:
98 return getTagRecordHashForUdt<EnumRecord>(Type);
99 default:
100 assert(false && "Type is not a tag record!");
101 }
102 return make_error<StringError>("Invalid record type",
103 inconvertibleErrorCode());
104 }
105
hashTypeRecord(const CVType & Rec)106 Expected<uint32_t> llvm::pdb::hashTypeRecord(const CVType &Rec) {
107 switch (Rec.kind()) {
108 case LF_CLASS:
109 case LF_STRUCTURE:
110 case LF_INTERFACE:
111 return getHashForUdt<ClassRecord>(Rec);
112 case LF_UNION:
113 return getHashForUdt<UnionRecord>(Rec);
114 case LF_ENUM:
115 return getHashForUdt<EnumRecord>(Rec);
116
117 case LF_UDT_SRC_LINE:
118 return getSourceLineHash<UdtSourceLineRecord>(Rec);
119 case LF_UDT_MOD_SRC_LINE:
120 return getSourceLineHash<UdtModSourceLineRecord>(Rec);
121
122 default:
123 break;
124 }
125
126 // Run CRC32 over the bytes. This corresponds to `hashBufv8`.
127 JamCRC JC(/*Init=*/0U);
128 ArrayRef<char> Bytes(reinterpret_cast<const char *>(Rec.data().data()),
129 Rec.data().size());
130 JC.update(Bytes);
131 return JC.getCRC();
132 }
133