130 lines · cpp
1//===- TpiHashing.cpp -----------------------------------------------------===//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-exception6//7//===----------------------------------------------------------------------===//8 9#include "llvm/DebugInfo/PDB/Native/TpiHashing.h"10 11#include "llvm/DebugInfo/CodeView/TypeDeserializer.h"12#include "llvm/DebugInfo/PDB/Native/Hash.h"13#include "llvm/Support/CRC.h"14 15using namespace llvm;16using namespace llvm::codeview;17using namespace llvm::pdb;18 19// Corresponds to `fUDTAnon`.20static bool isAnonymous(StringRef Name) {21 return Name == "<unnamed-tag>" || Name == "__unnamed" ||22 Name.ends_with("::<unnamed-tag>") || Name.ends_with("::__unnamed");23}24 25// Computes the hash for a user-defined type record. This could be a struct,26// class, union, or enum.27static uint32_t getHashForUdt(const TagRecord &Rec,28 ArrayRef<uint8_t> FullRecord) {29 ClassOptions Opts = Rec.getOptions();30 bool ForwardRef = bool(Opts & ClassOptions::ForwardReference);31 bool Scoped = bool(Opts & ClassOptions::Scoped);32 bool HasUniqueName = bool(Opts & ClassOptions::HasUniqueName);33 bool IsAnon = HasUniqueName && isAnonymous(Rec.getName());34 35 if (!ForwardRef && !Scoped && !IsAnon)36 return hashStringV1(Rec.getName());37 if (!ForwardRef && HasUniqueName && !IsAnon)38 return hashStringV1(Rec.getUniqueName());39 return hashBufferV8(FullRecord);40}41 42template <typename T>43static Expected<uint32_t> getHashForUdt(const CVType &Rec) {44 T Deserialized;45 if (auto E = TypeDeserializer::deserializeAs(const_cast<CVType &>(Rec),46 Deserialized))47 return std::move(E);48 return getHashForUdt(Deserialized, Rec.data());49}50 51template <typename T>52static Expected<TagRecordHash> getTagRecordHashForUdt(const CVType &Rec) {53 T Deserialized;54 if (auto E = TypeDeserializer::deserializeAs(const_cast<CVType &>(Rec),55 Deserialized))56 return std::move(E);57 58 ClassOptions Opts = Deserialized.getOptions();59 60 bool ForwardRef = bool(Opts & ClassOptions::ForwardReference);61 62 uint32_t ThisRecordHash = getHashForUdt(Deserialized, Rec.data());63 64 // If we don't have a forward ref we can't compute the hash of it from the65 // full record because it requires hashing the entire buffer.66 if (!ForwardRef)67 return TagRecordHash{std::move(Deserialized), ThisRecordHash, 0};68 69 bool Scoped = bool(Opts & ClassOptions::Scoped);70 71 StringRef NameToHash =72 Scoped ? Deserialized.getUniqueName() : Deserialized.getName();73 uint32_t FullHash = hashStringV1(NameToHash);74 return TagRecordHash{std::move(Deserialized), FullHash, ThisRecordHash};75}76 77template <typename T>78static Expected<uint32_t> getSourceLineHash(const CVType &Rec) {79 T Deserialized;80 if (auto E = TypeDeserializer::deserializeAs(const_cast<CVType &>(Rec),81 Deserialized))82 return std::move(E);83 char Buf[4];84 support::endian::write32le(Buf, Deserialized.getUDT().getIndex());85 return hashStringV1(StringRef(Buf, 4));86}87 88Expected<TagRecordHash> llvm::pdb::hashTagRecord(const codeview::CVType &Type) {89 switch (Type.kind()) {90 case LF_CLASS:91 case LF_STRUCTURE:92 case LF_INTERFACE:93 return getTagRecordHashForUdt<ClassRecord>(Type);94 case LF_UNION:95 return getTagRecordHashForUdt<UnionRecord>(Type);96 case LF_ENUM:97 return getTagRecordHashForUdt<EnumRecord>(Type);98 default:99 assert(false && "Type is not a tag record!");100 }101 return make_error<StringError>("Invalid record type",102 inconvertibleErrorCode());103}104 105Expected<uint32_t> llvm::pdb::hashTypeRecord(const CVType &Rec) {106 switch (Rec.kind()) {107 case LF_CLASS:108 case LF_STRUCTURE:109 case LF_INTERFACE:110 return getHashForUdt<ClassRecord>(Rec);111 case LF_UNION:112 return getHashForUdt<UnionRecord>(Rec);113 case LF_ENUM:114 return getHashForUdt<EnumRecord>(Rec);115 116 case LF_UDT_SRC_LINE:117 return getSourceLineHash<UdtSourceLineRecord>(Rec);118 case LF_UDT_MOD_SRC_LINE:119 return getSourceLineHash<UdtModSourceLineRecord>(Rec);120 121 default:122 break;123 }124 125 // Run CRC32 over the bytes. This corresponds to `hashBufv8`.126 JamCRC JC(/*Init=*/0U);127 JC.update(Rec.data());128 return JC.getCRC();129}130