2946cd7010
to reflect the new license. We understand that people may be surprised that we're moving the header entirely to discuss the new license. We checked this carefully with the Foundation's lawyer and we believe this is the correct approach. Essentially, all code in the project is now made available by the LLVM project under our new license, so you will see that the license headers include that license only. Some of our contributors have contributed code under our old license, and accordingly, we have retained a copy of our old license notice in the top-level files in each project and repository. llvm-svn: 351636
86 lines
2.5 KiB
C++
86 lines
2.5 KiB
C++
//===- Hash.cpp - PDB Hash Functions --------------------------------------===//
|
|
//
|
|
// 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/PDB/Native/Hash.h"
|
|
#include "llvm/ADT/ArrayRef.h"
|
|
#include "llvm/Support/Endian.h"
|
|
#include "llvm/Support/JamCRC.h"
|
|
#include <cstdint>
|
|
|
|
using namespace llvm;
|
|
using namespace llvm::support;
|
|
|
|
// Corresponds to `Hasher::lhashPbCb` in PDB/include/misc.h.
|
|
// Used for name hash table and TPI/IPI hashes.
|
|
uint32_t pdb::hashStringV1(StringRef Str) {
|
|
uint32_t Result = 0;
|
|
uint32_t Size = Str.size();
|
|
|
|
ArrayRef<ulittle32_t> Longs(reinterpret_cast<const ulittle32_t *>(Str.data()),
|
|
Size / 4);
|
|
|
|
for (auto Value : Longs)
|
|
Result ^= Value;
|
|
|
|
const uint8_t *Remainder = reinterpret_cast<const uint8_t *>(Longs.end());
|
|
uint32_t RemainderSize = Size % 4;
|
|
|
|
// Maximum of 3 bytes left. Hash a 2 byte word if possible, then hash the
|
|
// possibly remaining 1 byte.
|
|
if (RemainderSize >= 2) {
|
|
uint16_t Value = *reinterpret_cast<const ulittle16_t *>(Remainder);
|
|
Result ^= static_cast<uint32_t>(Value);
|
|
Remainder += 2;
|
|
RemainderSize -= 2;
|
|
}
|
|
|
|
// hash possible odd byte
|
|
if (RemainderSize == 1) {
|
|
Result ^= *(Remainder++);
|
|
}
|
|
|
|
const uint32_t toLowerMask = 0x20202020;
|
|
Result |= toLowerMask;
|
|
Result ^= (Result >> 11);
|
|
|
|
return Result ^ (Result >> 16);
|
|
}
|
|
|
|
// Corresponds to `HasherV2::HashULONG` in PDB/include/misc.h.
|
|
// Used for name hash table.
|
|
uint32_t pdb::hashStringV2(StringRef Str) {
|
|
uint32_t Hash = 0xb170a1bf;
|
|
|
|
ArrayRef<char> Buffer(Str.begin(), Str.end());
|
|
|
|
ArrayRef<ulittle32_t> Items(
|
|
reinterpret_cast<const ulittle32_t *>(Buffer.data()),
|
|
Buffer.size() / sizeof(ulittle32_t));
|
|
for (ulittle32_t Item : Items) {
|
|
Hash += Item;
|
|
Hash += (Hash << 10);
|
|
Hash ^= (Hash >> 6);
|
|
}
|
|
Buffer = Buffer.slice(Items.size() * sizeof(ulittle32_t));
|
|
for (uint8_t Item : Buffer) {
|
|
Hash += Item;
|
|
Hash += (Hash << 10);
|
|
Hash ^= (Hash >> 6);
|
|
}
|
|
|
|
return Hash * 1664525U + 1013904223U;
|
|
}
|
|
|
|
// Corresponds to `SigForPbCb` in langapi/shared/crc32.h.
|
|
uint32_t pdb::hashBufferV8(ArrayRef<uint8_t> Buf) {
|
|
JamCRC JC(/*Init=*/0U);
|
|
JC.update(makeArrayRef<char>(reinterpret_cast<const char *>(Buf.data()),
|
|
Buf.size()));
|
|
return JC.getCRC();
|
|
}
|