mum.h
1 /* Copyright (c) 2016 Vladimir Makarov <vmakarov@gcc.gnu.org> 2 3 Permission is hereby granted, free of charge, to any person 4 obtaining a copy of this software and associated documentation 5 files (the "Software"), to deal in the Software without 6 restriction, including without limitation the rights to use, copy, 7 modify, merge, publish, distribute, sublicense, and/or sell copies 8 of the Software, and to permit persons to whom the Software is 9 furnished to do so, subject to the following conditions: 10 11 The above copyright notice and this permission notice shall be 12 included in all copies or substantial portions of the Software. 13 14 THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, 15 EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF 16 MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND 17 NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS 18 BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN 19 ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN 20 CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE 21 SOFTWARE. 22 */ 23 24 /* This file implements MUM (MUltiply and Mix) hashing. We randomize 25 input data by 64x64-bit multiplication and mixing hi- and low-parts 26 of the multiplication result by using an addition and then mix it 27 into the current state. We use prime numbers randomly generated 28 with the equal probability of their bit values for the 29 multiplication. When all primes are used once, the state is 30 randomized and the same prime numbers are used again for data 31 randomization. 32 33 The MUM hashing passes all SMHasher tests. Pseudo Random Number 34 Generator based on MUM also passes NIST Statistical Test Suite for 35 Random and Pseudorandom Number Generators for Cryptographic 36 Applications (version 2.2.1) with 1000 bitstreams each containing 37 1M bits. MUM hashing is also faster Spooky64 and City64 on small 38 strings (at least up to 512-bit) on Haswell and Power7. The MUM bulk 39 speed (speed on very long data) is bigger than Spooky and City on 40 Power7. On Haswell the bulk speed is bigger than Spooky one and 41 close to City speed. */ 42 43 #ifndef __MUM_HASH__ 44 #define __MUM_HASH__ 45 46 #include <stddef.h> 47 #include <stdlib.h> 48 #include <string.h> 49 #include <limits.h> 50 51 #ifdef _MSC_VER 52 typedef unsigned __int16 uint16_t; 53 typedef unsigned __int32 uint32_t; 54 typedef unsigned __int64 uint64_t; 55 #else 56 #include <stdint.h> 57 #endif 58 59 /* Macro saying to use 128-bit integers implemented by GCC for some 60 targets. */ 61 #ifndef _MUM_USE_INT128 62 /* In GCC uint128_t is defined if HOST_BITS_PER_WIDE_INT >= 64. 63 HOST_WIDE_INT is long if HOST_BITS_PER_LONG > HOST_BITS_PER_INT, 64 otherwise int. */ 65 #if defined(__GNUC__) && UINT_MAX != ULONG_MAX 66 #define _MUM_USE_INT128 1 67 #else 68 #define _MUM_USE_INT128 0 69 #endif 70 #endif 71 72 #if defined(__GNUC__) && ((__GNUC__ == 4) && (__GNUC_MINOR__ >= 9) || (__GNUC__ > 4)) 73 #define _MUM_FRESH_GCC 74 #endif 75 76 #if defined(__GNUC__) && !defined(__llvm__) && defined(_MUM_FRESH_GCC) 77 #define _MUM_ATTRIBUTE_UNUSED __attribute__((unused)) 78 #define _MUM_OPTIMIZE(opts) __attribute__((__optimize__ (opts))) 79 #define _MUM_TARGET(opts) __attribute__((__target__ (opts))) 80 #else 81 #define _MUM_ATTRIBUTE_UNUSED 82 #define _MUM_OPTIMIZE(opts) 83 #define _MUM_TARGET(opts) 84 #endif 85 86 87 /* Here are different primes randomly generated with the equal 88 probability of their bit values. They are used to randomize input 89 values. */ 90 static uint64_t _mum_hash_step_prime = 0x2e0bb864e9ea7df5ULL; 91 static uint64_t _mum_key_step_prime = 0xcdb32970830fcaa1ULL; 92 static uint64_t _mum_block_start_prime = 0xc42b5e2e6480b23bULL; 93 static uint64_t _mum_unroll_prime = 0x7b51ec3d22f7096fULL; 94 static uint64_t _mum_tail_prime = 0xaf47d47c99b1461bULL; 95 static uint64_t _mum_finish_prime1 = 0xa9a7ae7ceff79f3fULL; 96 static uint64_t _mum_finish_prime2 = 0xaf47d47c99b1461bULL; 97 98 static uint64_t _mum_primes [] = { 99 0X9ebdcae10d981691, 0X32b9b9b97a27ac7d, 0X29b5584d83d35bbd, 0X4b04e0e61401255f, 100 0X25e8f7b1f1c9d027, 0X80d4c8c000f3e881, 0Xbd1255431904b9dd, 0X8a3bd4485eee6d81, 101 0X3bc721b2aad05197, 0X71b1a19b907d6e33, 0X525e6c1084a8534b, 0X9e4c2cd340c1299f, 102 0Xde3add92e94caa37, 0X7e14eadb1f65311d, 0X3f5aa40f89812853, 0X33b15a3b587d15c9, 103 }; 104 105 /* Multiply 64-bit V and P and return sum of high and low parts of the 106 result. */ 107 static inline uint64_t 108 _mum (uint64_t v, uint64_t p) { 109 uint64_t hi, lo; 110 #if _MUM_USE_INT128 111 #if defined(__aarch64__) 112 /* AARCH64 needs 2 insns to calculate 128-bit result of the 113 multiplication. If we use a generic code we actually call a 114 function doing 128x128->128 bit multiplication. The function is 115 very slow. */ 116 lo = v * p, hi; 117 asm ("umulh %0, %1, %2" : "=r" (hi) : "r" (v), "r" (p)); 118 #else 119 __uint128_t r = (__uint128_t) v * (__uint128_t) p; 120 hi = (uint64_t) (r >> 64); 121 lo = (uint64_t) r; 122 #endif 123 #else 124 /* Implementation of 64x64->128-bit multiplication by four 32x32->64 125 bit multiplication. */ 126 uint64_t hv = v >> 32, hp = p >> 32; 127 uint64_t lv = (uint32_t) v, lp = (uint32_t) p; 128 uint64_t rh = hv * hp; 129 uint64_t rm_0 = hv * lp; 130 uint64_t rm_1 = hp * lv; 131 uint64_t rl = lv * lp; 132 uint64_t t, carry = 0; 133 134 /* We could ignore a carry bit here if we did not care about the 135 same hash for 32-bit and 64-bit targets. */ 136 t = rl + (rm_0 << 32); 137 #ifdef MUM_TARGET_INDEPENDENT_HASH 138 carry = t < rl; 139 #endif 140 lo = t + (rm_1 << 32); 141 #ifdef MUM_TARGET_INDEPENDENT_HASH 142 carry += lo < t; 143 #endif 144 hi = rh + (rm_0 >> 32) + (rm_1 >> 32) + carry; 145 #endif 146 /* We could use XOR here too but, for some reasons, on Haswell and 147 Power7 using an addition improves hashing performance by 10% for 148 small strings. */ 149 return hi + lo; 150 } 151 152 #if defined(_MSC_VER) 153 #define _mum_bswap_32(x) _byteswap_uint32_t (x) 154 #define _mum_bswap_64(x) _byteswap_uint64_t (x) 155 #elif defined(__APPLE__) 156 #include <libkern/OSByteOrder.h> 157 #define _mum_bswap_32(x) OSSwapInt32 (x) 158 #define _mum_bswap_64(x) OSSwapInt64 (x) 159 #elif defined(__GNUC__) 160 #define _mum_bswap32(x) __builtin_bswap32 (x) 161 #define _mum_bswap64(x) __builtin_bswap64 (x) 162 #else 163 #include <byteswap.h> 164 #define _mum_bswap32(x) bswap32 (x) 165 #define _mum_bswap64(x) bswap64 (x) 166 #endif 167 168 static inline uint64_t 169 _mum_le (uint64_t v) { 170 #if __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__ || !defined(MUM_TARGET_INDEPENDENT_HASH) 171 return v; 172 #elif __BYTE_ORDER__ == __ORDER_BIG_ENDIAN__ 173 return _mum_bswap64 (v); 174 #else 175 #error "Unknown endianness" 176 #endif 177 } 178 179 static inline uint32_t 180 _mum_le32 (uint32_t v) { 181 #if __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__ || !defined(MUM_TARGET_INDEPENDENT_HASH) 182 return v; 183 #elif __BYTE_ORDER__ == __ORDER_BIG_ENDIAN__ 184 return _mum_bswap32 (v); 185 #else 186 #error "Unknown endianness" 187 #endif 188 } 189 190 /* Macro defining how many times the most nested loop in 191 _mum_hash_aligned will be unrolled by the compiler (although it can 192 make an own decision:). Use only a constant here to help a 193 compiler to unroll a major loop. 194 195 The macro value affects the result hash for strings > 128 bit. The 196 unroll factor greatly affects the hashing speed. We prefer the 197 speed. */ 198 #ifndef _MUM_UNROLL_FACTOR_POWER 199 #if defined(__PPC64__) && !defined(MUM_TARGET_INDEPENDENT_HASH) 200 #define _MUM_UNROLL_FACTOR_POWER 3 201 #elif defined(__aarch64__) && !defined(MUM_TARGET_INDEPENDENT_HASH) 202 #define _MUM_UNROLL_FACTOR_POWER 4 203 #else 204 #define _MUM_UNROLL_FACTOR_POWER 2 205 #endif 206 #endif 207 208 #if _MUM_UNROLL_FACTOR_POWER < 1 209 #error "too small unroll factor" 210 #elif _MUM_UNROLL_FACTOR_POWER > 4 211 #error "We have not enough primes for such unroll factor" 212 #endif 213 214 #define _MUM_UNROLL_FACTOR (1 << _MUM_UNROLL_FACTOR_POWER) 215 216 static inline uint64_t _MUM_OPTIMIZE("unroll-loops") 217 _mum_hash_aligned (uint64_t start, const void *key, size_t len) { 218 uint64_t result = start; 219 const unsigned char *str = (const unsigned char *) key; 220 uint64_t u64; 221 int i; 222 size_t n; 223 224 result = _mum (result, _mum_block_start_prime); 225 while (len > _MUM_UNROLL_FACTOR * sizeof (uint64_t)) { 226 /* This loop could be vectorized when we have vector insns for 227 64x64->128-bit multiplication. AVX2 currently only have a 228 vector insn for 4 32x32->64-bit multiplication. */ 229 for (i = 0; i < _MUM_UNROLL_FACTOR; i++) 230 result ^= _mum (_mum_le (((uint64_t *) str)[i]), _mum_primes[i]); 231 len -= _MUM_UNROLL_FACTOR * sizeof (uint64_t); 232 str += _MUM_UNROLL_FACTOR * sizeof (uint64_t); 233 /* We will use the same prime numbers on the next iterations -- 234 randomize the state. */ 235 result = _mum (result, _mum_unroll_prime); 236 } 237 n = len / sizeof (uint64_t); 238 for (i = 0; i < (int)n; i++) 239 result ^= _mum (_mum_le (((uint64_t *) str)[i]), _mum_primes[i]); 240 len -= n * sizeof (uint64_t); str += n * sizeof (uint64_t); 241 switch (len) { 242 case 7: 243 u64 = _mum_le32 (*(uint32_t *) str); 244 u64 |= (uint64_t) str[4] << 32; 245 u64 |= (uint64_t) str[5] << 40; 246 u64 |= (uint64_t) str[6] << 48; 247 return result ^ _mum (u64, _mum_tail_prime); 248 case 6: 249 u64 = _mum_le32 (*(uint32_t *) str); 250 u64 |= (uint64_t) str[4] << 32; 251 u64 |= (uint64_t) str[5] << 40; 252 return result ^ _mum (u64, _mum_tail_prime); 253 case 5: 254 u64 = _mum_le32 (*(uint32_t *) str); 255 u64 |= (uint64_t) str[4] << 32; 256 return result ^ _mum (u64, _mum_tail_prime); 257 case 4: 258 u64 = _mum_le32 (*(uint32_t *) str); 259 return result ^ _mum (u64, _mum_tail_prime); 260 case 3: 261 u64 = str[0]; 262 u64 |= (uint64_t) str[1] << 8; 263 u64 |= (uint64_t) str[2] << 16; 264 return result ^ _mum (u64, _mum_tail_prime); 265 case 2: 266 u64 = str[0]; 267 u64 |= (uint64_t) str[1] << 8; 268 return result ^ _mum (u64, _mum_tail_prime); 269 case 1: 270 u64 = str[0]; 271 return result ^ _mum (u64, _mum_tail_prime); 272 } 273 return result; 274 } 275 276 /* Final randomization of H. */ 277 static inline uint64_t 278 _mum_final (uint64_t h) { 279 h ^= _mum (h, _mum_finish_prime1); 280 h ^= _mum (h, _mum_finish_prime2); 281 return h; 282 } 283 284 #if defined(__x86_64__) && defined(_MUM_FRESH_GCC) 285 286 /* We want to use AVX2 insn MULX instead of generic x86-64 MULQ where 287 it is possible. Although on modern Intel processors MULQ takes 288 3-cycles vs. 4 for MULX, MULX permits more freedom in insn 289 scheduling as it uses less fixed registers. */ 290 static inline uint64_t _MUM_TARGET("arch=haswell") 291 _mum_hash_avx2 (const void * key, size_t len, uint64_t seed) { 292 return _mum_final (_mum_hash_aligned (seed + len, key, len)); 293 } 294 #endif 295 296 #ifndef _MUM_UNALIGNED_ACCESS 297 #if defined(__x86_64__) || defined(__i386__) || defined(__PPC64__) \ 298 || defined(__s390__) || defined(__m32c__) || defined(cris) \ 299 || defined(__CR16__) || defined(__vax__) || defined(__m68k__) \ 300 || defined(__aarch64__) 301 #define _MUM_UNALIGNED_ACCESS 1 302 #else 303 #define _MUM_UNALIGNED_ACCESS 0 304 #endif 305 #endif 306 307 /* When we need an aligned access to data being hashed we move part of 308 the unaligned data to an aligned block of given size and then 309 process it, repeating processing the data by the block. */ 310 #ifndef _MUM_BLOCK_LEN 311 #define _MUM_BLOCK_LEN 1024 312 #endif 313 314 #if _MUM_BLOCK_LEN < 8 315 #error "too small block length" 316 #endif 317 318 static inline uint64_t 319 #if defined(__x86_64__) 320 _MUM_TARGET("inline-all-stringops") 321 #endif 322 _mum_hash_default (const void *key, size_t len, uint64_t seed) { 323 uint64_t result; 324 const unsigned char *str = (const unsigned char *) key; 325 size_t block_len; 326 uint64_t buf[_MUM_BLOCK_LEN / sizeof (uint64_t)]; 327 328 result = seed + len; 329 if (_MUM_UNALIGNED_ACCESS || ((size_t) str & 0x7) == 0) 330 result = _mum_hash_aligned (result, key, len); 331 else { 332 while (len != 0) { 333 block_len = len < _MUM_BLOCK_LEN ? len : _MUM_BLOCK_LEN; 334 memmove (buf, str, block_len); 335 result = _mum_hash_aligned (result, buf, block_len); 336 len -= block_len; 337 str += block_len; 338 } 339 } 340 return _mum_final (result); 341 } 342 343 static inline uint64_t 344 _mum_next_factor (void) { 345 uint64_t start = 0; 346 int i; 347 348 for (i = 0; i < 8; i++) 349 start = (start << 8) | rand() % 256; 350 return start; 351 } 352 353 /* ++++++++++++++++++++++++++ Interface functions: +++++++++++++++++++ */ 354 355 /* Set random multiplicators depending on SEED. */ 356 static inline void 357 mum_hash_randomize (uint64_t seed) { 358 int i; 359 360 srand (seed); 361 _mum_hash_step_prime = _mum_next_factor (); 362 _mum_key_step_prime = _mum_next_factor (); 363 _mum_finish_prime1 = _mum_next_factor (); 364 _mum_finish_prime2 = _mum_next_factor (); 365 _mum_block_start_prime = _mum_next_factor (); 366 _mum_unroll_prime = _mum_next_factor (); 367 _mum_tail_prime = _mum_next_factor (); 368 for (i = 0; i < (int)(sizeof (_mum_primes) / sizeof (uint64_t)); i++) 369 _mum_primes[i] = _mum_next_factor (); 370 } 371 372 /* Start hashing data with SEED. Return the state. */ 373 static inline uint64_t 374 mum_hash_init (uint64_t seed) { 375 return seed; 376 } 377 378 /* Process data KEY with the state H and return the updated state. */ 379 static inline uint64_t 380 mum_hash_step (uint64_t h, uint64_t key) 381 { 382 return _mum (h, _mum_hash_step_prime) ^ _mum (key, _mum_key_step_prime); 383 } 384 385 /* Return the result of hashing using the current state H. */ 386 static inline uint64_t 387 mum_hash_finish (uint64_t h) { 388 return _mum_final (h); 389 } 390 391 /* Fast hashing of KEY with SEED. The hash is always the same for the 392 same key on any target. */ 393 static inline size_t 394 mum_hash64 (uint64_t key, uint64_t seed) { 395 return mum_hash_finish (mum_hash_step (mum_hash_init (seed), key)); 396 } 397 398 /* Hash data KEY of length LEN and SEED. The hash depends on the 399 target endianness and the unroll factor. */ 400 static inline uint64_t 401 mum_hash (const void *key, size_t len, uint64_t seed) { 402 #if defined(__x86_64__) && defined(_MUM_FRESH_GCC) 403 static int avx2_support = 0; 404 405 if (avx2_support > 0) 406 return _mum_hash_avx2 (key, len, seed); 407 else if (! avx2_support) { 408 __builtin_cpu_init (); 409 avx2_support = __builtin_cpu_supports ("avx2") ? 1 : -1; 410 if (avx2_support > 0) 411 return _mum_hash_avx2 (key, len, seed); 412 } 413 #endif 414 return _mum_hash_default (key, len, seed); 415 } 416 417 #endif