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>
getSourceLineHash(const CVType & Rec)53 static Expected<uint32_t> getSourceLineHash(const CVType &Rec) {
54 T Deserialized;
55 if (auto E = TypeDeserializer::deserializeAs(const_cast<CVType &>(Rec),
56 Deserialized))
57 return std::move(E);
58 char Buf[4];
59 support::endian::write32le(Buf, Deserialized.getUDT().getIndex());
60 return hashStringV1(StringRef(Buf, 4));
61 }
62
hashTypeRecord(const CVType & Rec)63 Expected<uint32_t> llvm::pdb::hashTypeRecord(const CVType &Rec) {
64 switch (Rec.kind()) {
65 case LF_CLASS:
66 case LF_STRUCTURE:
67 case LF_INTERFACE:
68 return getHashForUdt<ClassRecord>(Rec);
69 case LF_UNION:
70 return getHashForUdt<UnionRecord>(Rec);
71 case LF_ENUM:
72 return getHashForUdt<EnumRecord>(Rec);
73
74 case LF_UDT_SRC_LINE:
75 return getSourceLineHash<UdtSourceLineRecord>(Rec);
76 case LF_UDT_MOD_SRC_LINE:
77 return getSourceLineHash<UdtModSourceLineRecord>(Rec);
78
79 default:
80 break;
81 }
82
83 // Run CRC32 over the bytes. This corresponds to `hashBufv8`.
84 JamCRC JC(/*Init=*/0U);
85 ArrayRef<char> Bytes(reinterpret_cast<const char *>(Rec.data().data()),
86 Rec.data().size());
87 JC.update(Bytes);
88 return JC.getCRC();
89 }
90