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[Support] Integrate SipHash.cpp into libSupport. (#94394)
Start building it as part of the library, with some minor tweaks compared to the reference implementation: - clang-format to match libSupport - remove tracing support - add file header - templatize cROUNDS/dROUNDS, as well as 8B/16B result length - replace assert with static_assert - use LLVM_FALLTHROUGH This also exports interfaces for SipHash-2-4-64/-128, and tests them using the reference test vectors.
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‎llvm/include/llvm/Support/SipHash.h‎

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//===--- SipHash.h - An ABI-stable string SipHash ---------------*- C++ -*-===//
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//
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// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
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// See https://llvm.org/LICENSE.txt for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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//
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//===----------------------------------------------------------------------===//
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//
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// An implementation of SipHash, a hash function optimized for speed on
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// short inputs. Based on the SipHash reference implementation.
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//
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//===----------------------------------------------------------------------===//
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#ifndef LLVM_SUPPORT_SIPHASH_H
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#define LLVM_SUPPORT_SIPHASH_H
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#include <cstdint>
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namespace llvm {
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template <typename T> class ArrayRef;
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/// Computes a SipHash-2-4 64-bit result.
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void getSipHash_2_4_64(ArrayRef<uint8_t> In, const uint8_t (&K)[16],
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uint8_t (&Out)[8]);
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/// Computes a SipHash-2-4 128-bit result.
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void getSipHash_2_4_128(ArrayRef<uint8_t> In, const uint8_t (&K)[16],
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uint8_t (&Out)[16]);
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} // end namespace llvm
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#endif

‎llvm/lib/Support/CMakeLists.txt‎

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@@ -127,9 +127,6 @@ endif()
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add_subdirectory(BLAKE3)
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# Temporarily ignore SipHash.cpp before we fully integrate it into LLVMSupport.
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set(LLVM_OPTIONAL_SOURCES SipHash.cpp)
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add_llvm_component_library(LLVMSupport
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ABIBreak.cpp
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AMDGPUMetadata.cpp
@@ -227,6 +224,7 @@ add_llvm_component_library(LLVMSupport
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SHA1.cpp
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SHA256.cpp
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Signposts.cpp
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SipHash.cpp
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SlowDynamicAPInt.cpp
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SmallPtrSet.cpp
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SmallVector.cpp

‎llvm/lib/Support/SipHash.cpp‎

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@@ -1,185 +1,155 @@
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/*
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SipHash reference C implementation
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Copyright (c) 2012-2022 Jean-Philippe Aumasson
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<[email protected]>
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Copyright (c) 2012-2014 Daniel J. Bernstein <[email protected]>
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To the extent possible under law, the author(s) have dedicated all copyright
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and related and neighboring rights to this software to the public domain
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worldwide. This software is distributed without any warranty.
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You should have received a copy of the CC0 Public Domain Dedication along
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with
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this software. If not, see
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<http://creativecommons.org/publicdomain/zero/1.0/>.
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*/
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#include "siphash.h"
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#include <assert.h>
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#include <stddef.h>
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#include <stdint.h>
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/* default: SipHash-2-4 */
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#ifndef cROUNDS
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#define cROUNDS 2
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#endif
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#ifndef dROUNDS
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#define dROUNDS 4
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#endif
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//===--- SipHash.cpp - An ABI-stable string hash --------------------------===//
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//
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// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
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// See https://llvm.org/LICENSE.txt for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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//
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//===----------------------------------------------------------------------===//
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#include "llvm/Support/SipHash.h"
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#include "llvm/ADT/ArrayRef.h"
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#include "llvm/Support/Compiler.h"
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#include "llvm/Support/Endian.h"
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#include <cstdint>
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using namespace llvm;
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using namespace support;
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// Lightly adapted from the SipHash reference C implementation:
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// https://github.com/veorq/SipHash
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// by Jean-Philippe Aumasson and Daniel J. Bernstein
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3122
#define ROTL(x, b) (uint64_t)(((x) << (b)) | ((x) >> (64 - (b))))
3223

33-
#define U32TO8_LE(p, v) \
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(p)[0] = (uint8_t)((v)); \
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(p)[1] = (uint8_t)((v) >> 8); \
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(p)[2] = (uint8_t)((v) >> 16); \
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(p)[3] = (uint8_t)((v) >> 24);
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#define U64TO8_LE(p, v) \
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U32TO8_LE((p), (uint32_t)((v))); \
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U32TO8_LE((p) + 4, (uint32_t)((v) >> 32));
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#define U8TO64_LE(p) \
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(((uint64_t)((p)[0])) | ((uint64_t)((p)[1]) << 8) | \
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((uint64_t)((p)[2]) << 16) | ((uint64_t)((p)[3]) << 24) | \
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((uint64_t)((p)[4]) << 32) | ((uint64_t)((p)[5]) << 40) | \
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((uint64_t)((p)[6]) << 48) | ((uint64_t)((p)[7]) << 56))
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#define SIPROUND \
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do { \
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v0 += v1; \
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v1 = ROTL(v1, 13); \
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v1 ^= v0; \
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v0 = ROTL(v0, 32); \
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v2 += v3; \
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v3 = ROTL(v3, 16); \
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v3 ^= v2; \
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v0 += v3; \
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v3 = ROTL(v3, 21); \
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v3 ^= v0; \
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v2 += v1; \
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v1 = ROTL(v1, 17); \
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v1 ^= v2; \
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v2 = ROTL(v2, 32); \
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} while (0)
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#ifdef DEBUG_SIPHASH
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#include <stdio.h>
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#define TRACE \
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do { \
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printf("(%3zu) v0 %016" PRIx64 "\n", inlen, v0); \
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printf("(%3zu) v1 %016" PRIx64 "\n", inlen, v1); \
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printf("(%3zu) v2 %016" PRIx64 "\n", inlen, v2); \
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printf("(%3zu) v3 %016" PRIx64 "\n", inlen, v3); \
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} while (0)
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#else
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#define TRACE
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#endif
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/*
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Computes a SipHash value
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*in: pointer to input data (read-only)
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inlen: input data length in bytes (any size_t value)
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*k: pointer to the key data (read-only), must be 16 bytes
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*out: pointer to output data (write-only), outlen bytes must be allocated
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outlen: length of the output in bytes, must be 8 or 16
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*/
89-
int siphash(const void *in, const size_t inlen, const void *k, uint8_t *out,
90-
const size_t outlen) {
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92-
const unsigned char *ni = (const unsigned char *)in;
93-
const unsigned char *kk = (const unsigned char *)k;
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95-
assert((outlen == 8) || (outlen == 16));
96-
uint64_t v0 = UINT64_C(0x736f6d6570736575);
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uint64_t v1 = UINT64_C(0x646f72616e646f6d);
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uint64_t v2 = UINT64_C(0x6c7967656e657261);
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uint64_t v3 = UINT64_C(0x7465646279746573);
100-
uint64_t k0 = U8TO64_LE(kk);
101-
uint64_t k1 = U8TO64_LE(kk + 8);
102-
uint64_t m;
103-
int i;
104-
const unsigned char *end = ni + inlen - (inlen % sizeof(uint64_t));
105-
const int left = inlen & 7;
106-
uint64_t b = ((uint64_t)inlen) << 56;
107-
v3 ^= k1;
108-
v2 ^= k0;
109-
v1 ^= k1;
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v0 ^= k0;
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112-
if (outlen == 16)
113-
v1 ^= 0xee;
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115-
for (; ni != end; ni += 8) {
116-
m = U8TO64_LE(ni);
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v3 ^= m;
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119-
TRACE;
120-
for (i = 0; i < cROUNDS; ++i)
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SIPROUND;
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v0 ^= m;
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}
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126-
switch (left) {
127-
case 7:
128-
b |= ((uint64_t)ni[6]) << 48;
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/* FALLTHRU */
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case 6:
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b |= ((uint64_t)ni[5]) << 40;
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/* FALLTHRU */
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case 5:
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b |= ((uint64_t)ni[4]) << 32;
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/* FALLTHRU */
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case 4:
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b |= ((uint64_t)ni[3]) << 24;
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/* FALLTHRU */
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case 3:
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b |= ((uint64_t)ni[2]) << 16;
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/* FALLTHRU */
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case 2:
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b |= ((uint64_t)ni[1]) << 8;
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/* FALLTHRU */
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case 1:
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b |= ((uint64_t)ni[0]);
147-
break;
148-
case 0:
149-
break;
150-
}
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152-
v3 ^= b;
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154-
TRACE;
155-
for (i = 0; i < cROUNDS; ++i)
156-
SIPROUND;
157-
158-
v0 ^= b;
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160-
if (outlen == 16)
161-
v2 ^= 0xee;
162-
else
163-
v2 ^= 0xff;
25+
do { \
26+
v0 += v1; \
27+
v1 = ROTL(v1, 13); \
28+
v1 ^= v0; \
29+
v0 = ROTL(v0, 32); \
30+
v2 += v3; \
31+
v3 = ROTL(v3, 16); \
32+
v3 ^= v2; \
33+
v0 += v3; \
34+
v3 = ROTL(v3, 21); \
35+
v3 ^= v0; \
36+
v2 += v1; \
37+
v1 = ROTL(v1, 17); \
38+
v1 ^= v2; \
39+
v2 = ROTL(v2, 32); \
40+
} while (0)
41+
42+
namespace {
43+
44+
/// Computes a SipHash value
45+
///
46+
/// \param in: pointer to input data (read-only)
47+
/// \param inlen: input data length in bytes (any size_t value)
48+
/// \param k: reference to the key data 16-byte array (read-only)
49+
/// \returns output data, must be 8 or 16 bytes
50+
///
51+
template <int cROUNDS, int dROUNDS, size_t outlen>
52+
void siphash(const unsigned char *in, uint64_t inlen,
53+
const unsigned char (&k)[16], unsigned char (&out)[outlen]) {
54+
55+
const unsigned char *ni = (const unsigned char *)in;
56+
const unsigned char *kk = (const unsigned char *)k;
57+
58+
static_assert(outlen == 8 || outlen == 16, "result should be 8 or 16 bytes");
59+
60+
uint64_t v0 = UINT64_C(0x736f6d6570736575);
61+
uint64_t v1 = UINT64_C(0x646f72616e646f6d);
62+
uint64_t v2 = UINT64_C(0x6c7967656e657261);
63+
uint64_t v3 = UINT64_C(0x7465646279746573);
64+
uint64_t k0 = endian::read64le(kk);
65+
uint64_t k1 = endian::read64le(kk + 8);
66+
uint64_t m;
67+
int i;
68+
const unsigned char *end = ni + inlen - (inlen % sizeof(uint64_t));
69+
const int left = inlen & 7;
70+
uint64_t b = ((uint64_t)inlen) << 56;
71+
v3 ^= k1;
72+
v2 ^= k0;
73+
v1 ^= k1;
74+
v0 ^= k0;
75+
76+
if (outlen == 16)
77+
v1 ^= 0xee;
78+
79+
for (; ni != end; ni += 8) {
80+
m = endian::read64le(ni);
81+
v3 ^= m;
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165-
TRACE;
166-
for (i = 0; i < dROUNDS; ++i)
167-
SIPROUND;
168-
169-
b = v0 ^ v1 ^ v2 ^ v3;
170-
U64TO8_LE(out, b);
171-
172-
if (outlen == 8)
173-
return 0;
174-
175-
v1 ^= 0xdd;
83+
for (i = 0; i < cROUNDS; ++i)
84+
SIPROUND;
85+
86+
v0 ^= m;
87+
}
88+
89+
switch (left) {
90+
case 7:
91+
b |= ((uint64_t)ni[6]) << 48;
92+
LLVM_FALLTHROUGH;
93+
case 6:
94+
b |= ((uint64_t)ni[5]) << 40;
95+
LLVM_FALLTHROUGH;
96+
case 5:
97+
b |= ((uint64_t)ni[4]) << 32;
98+
LLVM_FALLTHROUGH;
99+
case 4:
100+
b |= ((uint64_t)ni[3]) << 24;
101+
LLVM_FALLTHROUGH;
102+
case 3:
103+
b |= ((uint64_t)ni[2]) << 16;
104+
LLVM_FALLTHROUGH;
105+
case 2:
106+
b |= ((uint64_t)ni[1]) << 8;
107+
LLVM_FALLTHROUGH;
108+
case 1:
109+
b |= ((uint64_t)ni[0]);
110+
break;
111+
case 0:
112+
break;
113+
}
114+
115+
v3 ^= b;
116+
117+
for (i = 0; i < cROUNDS; ++i)
118+
SIPROUND;
119+
120+
v0 ^= b;
121+
122+
if (outlen == 16)
123+
v2 ^= 0xee;
124+
else
125+
v2 ^= 0xff;
126+
127+
for (i = 0; i < dROUNDS; ++i)
128+
SIPROUND;
129+
130+
b = v0 ^ v1 ^ v2 ^ v3;
131+
endian::write64le(out, b);
132+
133+
if (outlen == 8)
134+
return;
135+
136+
v1 ^= 0xdd;
137+
138+
for (i = 0; i < dROUNDS; ++i)
139+
SIPROUND;
140+
141+
b = v0 ^ v1 ^ v2 ^ v3;
142+
endian::write64le(out + 8, b);
143+
}
176144

177-
TRACE;
178-
for (i = 0; i < dROUNDS; ++i)
179-
SIPROUND;
145+
} // end anonymous namespace
180146

181-
b = v0 ^ v1 ^ v2 ^ v3;
182-
U64TO8_LE(out + 8, b);
147+
void llvm::getSipHash_2_4_64(ArrayRef<uint8_t> In, const uint8_t (&K)[16],
148+
uint8_t (&Out)[8]) {
149+
siphash<2, 4>(In.data(), In.size(), K, Out);
150+
}
183151

184-
return 0;
152+
void llvm::getSipHash_2_4_128(ArrayRef<uint8_t> In, const uint8_t (&K)[16],
153+
uint8_t (&Out)[16]) {
154+
siphash<2, 4>(In.data(), In.size(), K, Out);
185155
}

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