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| //===- TypeHashing.cpp -------------------------------------------*- C++-*-===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
#include "llvm/DebugInfo/CodeView/TypeHashing.h"
#include "llvm/DebugInfo/CodeView/TypeIndexDiscovery.h"
#include "llvm/Support/SHA1.h"
using namespace llvm;
using namespace llvm::codeview;
LocallyHashedType DenseMapInfo<LocallyHashedType>::Empty{0, {}};
LocallyHashedType DenseMapInfo<LocallyHashedType>::Tombstone{hash_code(-1), {}};
static std::array<uint8_t, 8> EmptyHash = {
{0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00}};
static std::array<uint8_t, 8> TombstoneHash = {
{0xFF, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00}};
GloballyHashedType DenseMapInfo<GloballyHashedType>::Empty{EmptyHash};
GloballyHashedType DenseMapInfo<GloballyHashedType>::Tombstone{TombstoneHash};
LocallyHashedType LocallyHashedType::hashType(ArrayRef<uint8_t> RecordData) {
return {llvm::hash_value(RecordData), RecordData};
}
GloballyHashedType
GloballyHashedType::hashType(ArrayRef<uint8_t> RecordData,
ArrayRef<GloballyHashedType> PreviousTypes,
ArrayRef<GloballyHashedType> PreviousIds) {
SmallVector<TiReference, 4> Refs;
discoverTypeIndices(RecordData, Refs);
SHA1 S;
S.init();
uint32_t Off = 0;
S.update(RecordData.take_front(sizeof(RecordPrefix)));
RecordData = RecordData.drop_front(sizeof(RecordPrefix));
for (const auto &Ref : Refs) {
// Hash any data that comes before this TiRef.
uint32_t PreLen = Ref.Offset - Off;
ArrayRef<uint8_t> PreData = RecordData.slice(Off, PreLen);
S.update(PreData);
auto Prev = (Ref.Kind == TiRefKind::IndexRef) ? PreviousIds : PreviousTypes;
auto RefData = RecordData.slice(Ref.Offset, Ref.Count * sizeof(TypeIndex));
// For each type index referenced, add in the previously computed hash
// value of that type.
ArrayRef<TypeIndex> Indices(
reinterpret_cast<const TypeIndex *>(RefData.data()), Ref.Count);
for (TypeIndex TI : Indices) {
ArrayRef<uint8_t> BytesToHash;
if (TI.isSimple() || TI.isNoneType()) {
const uint8_t *IndexBytes = reinterpret_cast<const uint8_t *>(&TI);
BytesToHash = makeArrayRef(IndexBytes, sizeof(TypeIndex));
} else {
if (TI.toArrayIndex() >= Prev.size() ||
Prev[TI.toArrayIndex()].empty()) {
// There are references to yet-unhashed records. Suspend hashing for
// this record until all the other records are processed.
return {};
}
BytesToHash = Prev[TI.toArrayIndex()].Hash;
}
S.update(BytesToHash);
}
Off = Ref.Offset + Ref.Count * sizeof(TypeIndex);
}
// Don't forget to add in any trailing bytes.
auto TrailingBytes = RecordData.drop_front(Off);
S.update(TrailingBytes);
return {S.final().take_back(8)};
}
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