302 changes: 126 additions & 176 deletions llvm/lib/Support/SipHash.cpp
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/*
SipHash reference C implementation
Copyright (c) 2012-2022 Jean-Philippe Aumasson
<jeanphilippe.aumasson@gmail.com>
Copyright (c) 2012-2014 Daniel J. Bernstein <djb@cr.yp.to>
To the extent possible under law, the author(s) have dedicated all copyright
and related and neighboring rights to this software to the public domain
worldwide. This software is distributed without any warranty.
You should have received a copy of the CC0 Public Domain Dedication along
with
this software. If not, see
<http://creativecommons.org/publicdomain/zero/1.0/>.
*/

#include "siphash.h"
#include <assert.h>
#include <stddef.h>
#include <stdint.h>

/* default: SipHash-2-4 */
#ifndef cROUNDS
#define cROUNDS 2
#endif
#ifndef dROUNDS
#define dROUNDS 4
#endif
//===--- SipHash.cpp - An ABI-stable string hash --------------------------===//
//
// 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
//
//===----------------------------------------------------------------------===//

#define ROTL(x, b) (uint64_t)(((x) << (b)) | ((x) >> (64 - (b))))
#include "llvm/Support/Compiler.h"
#include <cstdint>

#define U32TO8_LE(p, v) \
(p)[0] = (uint8_t)((v)); \
(p)[1] = (uint8_t)((v) >> 8); \
(p)[2] = (uint8_t)((v) >> 16); \
(p)[3] = (uint8_t)((v) >> 24);
// Lightly adapted from the SipHash reference C implementation by
// Jean-Philippe Aumasson and Daniel J. Bernstein.

#define U64TO8_LE(p, v) \
U32TO8_LE((p), (uint32_t)((v))); \
U32TO8_LE((p) + 4, (uint32_t)((v) >> 32));
#define ROTL(x, b) (uint64_t)(((x) << (b)) | ((x) >> (64 - (b))))

#define U8TO64_LE(p) \
(((uint64_t)((p)[0])) | ((uint64_t)((p)[1]) << 8) | \
((uint64_t)((p)[2]) << 16) | ((uint64_t)((p)[3]) << 24) | \
((uint64_t)((p)[4]) << 32) | ((uint64_t)((p)[5]) << 40) | \
((uint64_t)((p)[6]) << 48) | ((uint64_t)((p)[7]) << 56))
(((uint64_t)((p)[0])) | ((uint64_t)((p)[1]) << 8) | \
((uint64_t)((p)[2]) << 16) | ((uint64_t)((p)[3]) << 24) | \
((uint64_t)((p)[4]) << 32) | ((uint64_t)((p)[5]) << 40) | \
((uint64_t)((p)[6]) << 48) | ((uint64_t)((p)[7]) << 56))

#define SIPROUND \
do { \
v0 += v1; \
v1 = ROTL(v1, 13); \
v1 ^= v0; \
v0 = ROTL(v0, 32); \
v2 += v3; \
v3 = ROTL(v3, 16); \
v3 ^= v2; \
v0 += v3; \
v3 = ROTL(v3, 21); \
v3 ^= v0; \
v2 += v1; \
v1 = ROTL(v1, 17); \
v1 ^= v2; \
v2 = ROTL(v2, 32); \
} while (0)

#ifdef DEBUG_SIPHASH
#include <stdio.h>

#define TRACE \
do { \
printf("(%3zu) v0 %016" PRIx64 "\n", inlen, v0); \
printf("(%3zu) v1 %016" PRIx64 "\n", inlen, v1); \
printf("(%3zu) v2 %016" PRIx64 "\n", inlen, v2); \
printf("(%3zu) v3 %016" PRIx64 "\n", inlen, v3); \
} while (0)
#else
#define TRACE
#endif

/*
Computes a SipHash value
*in: pointer to input data (read-only)
inlen: input data length in bytes (any size_t value)
*k: pointer to the key data (read-only), must be 16 bytes
*out: pointer to output data (write-only), outlen bytes must be allocated
outlen: length of the output in bytes, must be 8 or 16
*/
int siphash(const void *in, const size_t inlen, const void *k, uint8_t *out,
const size_t outlen) {

const unsigned char *ni = (const unsigned char *)in;
const unsigned char *kk = (const unsigned char *)k;

assert((outlen == 8) || (outlen == 16));
uint64_t v0 = UINT64_C(0x736f6d6570736575);
uint64_t v1 = UINT64_C(0x646f72616e646f6d);
uint64_t v2 = UINT64_C(0x6c7967656e657261);
uint64_t v3 = UINT64_C(0x7465646279746573);
uint64_t k0 = U8TO64_LE(kk);
uint64_t k1 = U8TO64_LE(kk + 8);
uint64_t m;
int i;
const unsigned char *end = ni + inlen - (inlen % sizeof(uint64_t));
const int left = inlen & 7;
uint64_t b = ((uint64_t)inlen) << 56;
v3 ^= k1;
v2 ^= k0;
v1 ^= k1;
v0 ^= k0;

if (outlen == 16)
v1 ^= 0xee;

for (; ni != end; ni += 8) {
m = U8TO64_LE(ni);
v3 ^= m;

TRACE;
for (i = 0; i < cROUNDS; ++i)
SIPROUND;

v0 ^= m;
}

switch (left) {
case 7:
b |= ((uint64_t)ni[6]) << 48;
/* FALLTHRU */
case 6:
b |= ((uint64_t)ni[5]) << 40;
/* FALLTHRU */
case 5:
b |= ((uint64_t)ni[4]) << 32;
/* FALLTHRU */
case 4:
b |= ((uint64_t)ni[3]) << 24;
/* FALLTHRU */
case 3:
b |= ((uint64_t)ni[2]) << 16;
/* FALLTHRU */
case 2:
b |= ((uint64_t)ni[1]) << 8;
/* FALLTHRU */
case 1:
b |= ((uint64_t)ni[0]);
break;
case 0:
break;
}

v3 ^= b;

TRACE;
for (i = 0; i < cROUNDS; ++i)
SIPROUND;

v0 ^= b;

if (outlen == 16)
v2 ^= 0xee;
else
v2 ^= 0xff;

TRACE;
for (i = 0; i < dROUNDS; ++i)
SIPROUND;
do { \
v0 += v1; \
v1 = ROTL(v1, 13); \
v1 ^= v0; \
v0 = ROTL(v0, 32); \
v2 += v3; \
v3 = ROTL(v3, 16); \
v3 ^= v2; \
v0 += v3; \
v3 = ROTL(v3, 21); \
v3 ^= v0; \
v2 += v1; \
v1 = ROTL(v1, 17); \
v1 ^= v2; \
v2 = ROTL(v2, 32); \
} while (0)

template <int cROUNDS, int dROUNDS, class ResultTy>
static inline ResultTy siphash(const unsigned char *in, uint64_t inlen,
const unsigned char (&k)[16]) {

const unsigned char *ni = (const unsigned char *)in;
const unsigned char *kk = (const unsigned char *)k;

static_assert(sizeof(ResultTy) == 8 || sizeof(ResultTy) == 16,
"result type should be uint64_t or uint128_t");
uint64_t v0 = UINT64_C(0x736f6d6570736575);
uint64_t v1 = UINT64_C(0x646f72616e646f6d);
uint64_t v2 = UINT64_C(0x6c7967656e657261);
uint64_t v3 = UINT64_C(0x7465646279746573);
uint64_t k0 = U8TO64_LE(kk);
uint64_t k1 = U8TO64_LE(kk + 8);
uint64_t m;
int i;
const unsigned char *end = ni + inlen - (inlen % sizeof(uint64_t));
const int left = inlen & 7;
uint64_t b = ((uint64_t)inlen) << 56;
v3 ^= k1;
v2 ^= k0;
v1 ^= k1;
v0 ^= k0;

if (sizeof(ResultTy) == 16)
v1 ^= 0xee;

for (; ni != end; ni += 8) {
m = U8TO64_LE(ni);
v3 ^= m;

b = v0 ^ v1 ^ v2 ^ v3;
U64TO8_LE(out, b);

if (outlen == 8)
return 0;

v1 ^= 0xdd;

TRACE;
for (i = 0; i < dROUNDS; ++i)
SIPROUND;

b = v0 ^ v1 ^ v2 ^ v3;
U64TO8_LE(out + 8, b);

return 0;
for (i = 0; i < cROUNDS; ++i)
SIPROUND;

v0 ^= m;
}

switch (left) {
case 7:
b |= ((uint64_t)ni[6]) << 48;
LLVM_FALLTHROUGH;
case 6:
b |= ((uint64_t)ni[5]) << 40;
LLVM_FALLTHROUGH;
case 5:
b |= ((uint64_t)ni[4]) << 32;
LLVM_FALLTHROUGH;
case 4:
b |= ((uint64_t)ni[3]) << 24;
LLVM_FALLTHROUGH;
case 3:
b |= ((uint64_t)ni[2]) << 16;
LLVM_FALLTHROUGH;
case 2:
b |= ((uint64_t)ni[1]) << 8;
LLVM_FALLTHROUGH;
case 1:
b |= ((uint64_t)ni[0]);
break;
case 0:
break;
}

v3 ^= b;

for (i = 0; i < cROUNDS; ++i)
SIPROUND;

v0 ^= b;

if (sizeof(ResultTy) == 16)
v2 ^= 0xee;
else
v2 ^= 0xff;

for (i = 0; i < dROUNDS; ++i)
SIPROUND;

b = v0 ^ v1 ^ v2 ^ v3;

uint64_t firstHalf = b;
if (sizeof(ResultTy) == 8)
return firstHalf;

v1 ^= 0xdd;

for (i = 0; i < dROUNDS; ++i)
SIPROUND;

b = v0 ^ v1 ^ v2 ^ v3;
uint64_t secondHalf = b;

return firstHalf | (ResultTy(secondHalf) << (sizeof(ResultTy) == 8 ? 0 : 64));
}