[llvm] [Support] Add llvm::xxh3_128bits (PR #95863)
Brendan Duke via llvm-commits
llvm-commits at lists.llvm.org
Mon Jun 17 16:14:29 PDT 2024
https://github.com/dukebw created https://github.com/llvm/llvm-project/pull/95863
Add a 128-bit xxhash function, following the existing `llvm::xxh3_64bits` and `llvm::xxHash` implementations. Previously, 48e93f57f1ee914ca29aa31bf2ccd916565a3610 added support for `llvm::xxh3_64bits`, which closely follows the upstream implementation at https://github.com/Cyan4973/xxHash, with simplifications from Devin Hussey's xxhash-clean.
However, it is desirable to have a larger 128-bit hash key for use cases such as filesystem checksums where chance of collision needs to be negligible.
So to that end this also ports over the 128-bit xxh3_128bits as `llvm::xxh3_128bits`.
Testing:
- Add a test based on xsum_sanity_check.c in upstream xxhash.
>From 90ce7bd9624ed81481f2203666ad88f08918762c Mon Sep 17 00:00:00 2001
From: Brendan Duke <brendanw.duke at gmail.com>
Date: Mon, 17 Jun 2024 17:16:53 +0000
Subject: [PATCH] [Support] Add llvm::xxh3_128bits
Add a 128-bit xxhash function, following the existing
`llvm::xxh3_64bits` and `llvm::xxHash` implementations.
Previously, 48e93f57f1ee914ca29aa31bf2ccd916565a3610 added support for
`llvm::xxh3_64bits`, which closely follows the upstream implementation
at https://github.com/Cyan4973/xxHash, with simplifications from Devin
Hussey's xxhash-clean.
However, it is desirable to have a larger 128-bit hash key for use cases
such as filesystem checksums where chance of collision needs to be
negligible.
So to that end this also ports over `llvm::xxh3_128bits`.
Testing:
- Add a test based on xsum_sanity_check.c in upstream xxhash.
---
llvm/include/llvm/Support/xxhash.h | 27 +-
llvm/lib/Support/xxhash.cpp | 594 ++++++++++++++++++++++++--
llvm/unittests/Support/xxhashTest.cpp | 69 +++
3 files changed, 655 insertions(+), 35 deletions(-)
diff --git a/llvm/include/llvm/Support/xxhash.h b/llvm/include/llvm/Support/xxhash.h
index 0cef3a54e50d7..5f8a7ab360abe 100644
--- a/llvm/include/llvm/Support/xxhash.h
+++ b/llvm/include/llvm/Support/xxhash.h
@@ -42,6 +42,7 @@
#include "llvm/ADT/StringRef.h"
namespace llvm {
+
uint64_t xxHash64(llvm::StringRef Data);
uint64_t xxHash64(llvm::ArrayRef<uint8_t> Data);
@@ -49,6 +50,30 @@ uint64_t xxh3_64bits(ArrayRef<uint8_t> data);
inline uint64_t xxh3_64bits(StringRef data) {
return xxh3_64bits(ArrayRef(data.bytes_begin(), data.size()));
}
-}
+
+/*-**********************************************************************
+ * XXH3 128-bit variant
+ ************************************************************************/
+
+/*!
+ * @brief The return value from 128-bit hashes.
+ *
+ * Stored in little endian order, although the fields themselves are in native
+ * endianness.
+ */
+struct XXH128_hash_t {
+ uint64_t low64; /*!< `value & 0xFFFFFFFFFFFFFFFF` */
+ uint64_t high64; /*!< `value >> 64` */
+
+ /// Convenience equality check operator.
+ bool operator==(const XXH128_hash_t rhs) const {
+ return low64 == rhs.low64 && high64 == rhs.high64;
+ }
+};
+
+/// XXH3's 128-bit variant.
+XXH128_hash_t xxh3_128bits(ArrayRef<uint8_t> data);
+
+} // namespace llvm
#endif
diff --git a/llvm/lib/Support/xxhash.cpp b/llvm/lib/Support/xxhash.cpp
index 577f14189caff..9aa6f16b08bb2 100644
--- a/llvm/lib/Support/xxhash.cpp
+++ b/llvm/lib/Support/xxhash.cpp
@@ -1,36 +1,36 @@
/*
-* xxHash - Fast Hash algorithm
-* Copyright (C) 2012-2021, Yann Collet
-*
-* BSD 2-Clause License (http://www.opensource.org/licenses/bsd-license.php)
-*
-* Redistribution and use in source and binary forms, with or without
-* modification, are permitted provided that the following conditions are
-* met:
-*
-* * Redistributions of source code must retain the above copyright
-* notice, this list of conditions and the following disclaimer.
-* * Redistributions in binary form must reproduce the above
-* copyright notice, this list of conditions and the following disclaimer
-* in the documentation and/or other materials provided with the
-* distribution.
-*
-* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
-* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
-* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
-* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
-* OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
-* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
-* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
-* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
-* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
-* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
-* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
-*
-* You can contact the author at :
-* - xxHash homepage: http://www.xxhash.com
-* - xxHash source repository : https://github.com/Cyan4973/xxHash
-*/
+ * xxHash - Extremely Fast Hash algorithm
+ * Copyright (C) 2012-2023, Yann Collet
+ *
+ * BSD 2-Clause License (http://www.opensource.org/licenses/bsd-license.php)
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are
+ * met:
+ *
+ * * Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ * * Redistributions in binary form must reproduce the above
+ * copyright notice, this list of conditions and the following disclaimer
+ * in the documentation and/or other materials provided with the
+ * distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ * You can contact the author at :
+ * - xxHash homepage: http://www.xxhash.com
+ * - xxHash source repository : https://github.com/Cyan4973/xxHash
+ */
// xxhash64 is based on commit d2df04efcbef7d7f6886d345861e5dfda4edacc1. Removed
// everything but a simple interface for computing xxh64.
@@ -38,6 +38,9 @@
// xxh3_64bits is based on commit d5891596637d21366b9b1dcf2c0007a3edb26a9e (July
// 2023).
+// xxh3_128bits is based on commit b0adcc54188c3130b1793e7b19c62eb1e669f7df
+// (June 2024).
+
#include "llvm/Support/xxhash.h"
#include "llvm/Support/Compiler.h"
#include "llvm/Support/Endian.h"
@@ -297,12 +300,12 @@ static uint64_t XXH3_len_17to128_64b(const uint8_t *input, size_t len,
}
constexpr size_t XXH3_MIDSIZE_MAX = 240;
+constexpr size_t XXH3_MIDSIZE_STARTOFFSET = 3;
+constexpr size_t XXH3_MIDSIZE_LASTOFFSET = 17;
LLVM_ATTRIBUTE_NOINLINE
static uint64_t XXH3_len_129to240_64b(const uint8_t *input, size_t len,
const uint8_t *secret, uint64_t seed) {
- constexpr size_t XXH3_MIDSIZE_STARTOFFSET = 3;
- constexpr size_t XXH3_MIDSIZE_LASTOFFSET = 17;
uint64_t acc = (uint64_t)len * PRIME64_1;
const unsigned nbRounds = len / 16;
for (unsigned i = 0; i < 8; ++i)
@@ -405,3 +408,526 @@ uint64_t llvm::xxh3_64bits(ArrayRef<uint8_t> data) {
return XXH3_len_129to240_64b(in, len, kSecret, 0);
return XXH3_hashLong_64b(in, len, kSecret, sizeof(kSecret));
}
+
+/* ==========================================
+ * XXH3 128 bits (a.k.a XXH128)
+ * ==========================================
+ * XXH3's 128-bit variant has better mixing and strength than the 64-bit
+ * variant, even without counting the significantly larger output size.
+ *
+ * For example, extra steps are taken to avoid the seed-dependent collisions
+ * in 17-240 byte inputs (See XXH3_mix16B and XXH128_mix32B).
+ *
+ * This strength naturally comes at the cost of some speed, especially on short
+ * lengths. Note that longer hashes are about as fast as the 64-bit version
+ * due to it using only a slight modification of the 64-bit loop.
+ *
+ * XXH128 is also more oriented towards 64-bit machines. It is still extremely
+ * fast for a _128-bit_ hash on 32-bit (it usually clears XXH64).
+ */
+
+/*!
+ * @internal
+ * @def XXH_rotl32(x,r)
+ * @brief 32-bit rotate left.
+ *
+ * @param x The 32-bit integer to be rotated.
+ * @param r The number of bits to rotate.
+ * @pre
+ * @p r > 0 && @p r < 32
+ * @note
+ * @p x and @p r may be evaluated multiple times.
+ * @return The rotated result.
+ */
+#if __has_builtin(__builtin_rotateleft32) && \
+ __has_builtin(__builtin_rotateleft64)
+#define XXH_rotl32 __builtin_rotateleft32
+#define XXH_rotl64 __builtin_rotateleft64
+/* Note: although _rotl exists for minGW (GCC under windows), performance seems
+ * poor */
+#elif defined(_MSC_VER)
+#define XXH_rotl32(x, r) _rotl(x, r)
+#define XXH_rotl64(x, r) _rotl64(x, r)
+#else
+#define XXH_rotl32(x, r) (((x) << (r)) | ((x) >> (32 - (r))))
+#define XXH_rotl64(x, r) (((x) << (r)) | ((x) >> (64 - (r))))
+#endif
+
+#if defined(_MSC_VER) && defined(_M_IX86)
+#define XXH_mult32to64(x, y) __emulu((unsigned)(x), (unsigned)(y))
+#else
+/*
+ * Downcast + upcast is usually better than masking on older compilers like
+ * GCC 4.2 (especially 32-bit ones), all without affecting newer compilers.
+ *
+ * The other method, (x & 0xFFFFFFFF) * (y & 0xFFFFFFFF), will AND both operands
+ * and perform a full 64x64 multiply -- entirely redundant on 32-bit.
+ */
+#define XXH_mult32to64(x, y) ((uint64_t)(uint32_t)(x) * (uint64_t)(uint32_t)(y))
+#endif
+
+/*!
+ * @brief Calculates a 64->128-bit long multiply.
+ *
+ * Uses `__uint128_t` and `_umul128` if available, otherwise uses a scalar
+ * version.
+ *
+ * @param lhs , rhs The 64-bit integers to be multiplied
+ * @return The 128-bit result represented in an @ref XXH128_hash_t.
+ */
+static XXH128_hash_t XXH_mult64to128(uint64_t lhs, uint64_t rhs) {
+ /*
+ * GCC/Clang __uint128_t method.
+ *
+ * On most 64-bit targets, GCC and Clang define a __uint128_t type.
+ * This is usually the best way as it usually uses a native long 64-bit
+ * multiply, such as MULQ on x86_64 or MUL + UMULH on aarch64.
+ *
+ * Usually.
+ *
+ * Despite being a 32-bit platform, Clang (and emscripten) define this type
+ * despite not having the arithmetic for it. This results in a laggy
+ * compiler builtin call which calculates a full 128-bit multiply.
+ * In that case it is best to use the portable one.
+ * https://github.com/Cyan4973/xxHash/issues/211#issuecomment-515575677
+ */
+#if (defined(__GNUC__) || defined(__clang__)) && !defined(__wasm__) && \
+ defined(__SIZEOF_INT128__) || \
+ (defined(_INTEGRAL_MAX_BITS) && _INTEGRAL_MAX_BITS >= 128)
+
+ __uint128_t const product = (__uint128_t)lhs * (__uint128_t)rhs;
+ XXH128_hash_t r128;
+ r128.low64 = (uint64_t)(product);
+ r128.high64 = (uint64_t)(product >> 64);
+ return r128;
+
+ /*
+ * MSVC for x64's _umul128 method.
+ *
+ * uint64_t _umul128(uint64_t Multiplier, uint64_t Multiplicand, uint64_t
+ * *HighProduct);
+ *
+ * This compiles to single operand MUL on x64.
+ */
+#elif (defined(_M_X64) || defined(_M_IA64)) && !defined(_M_ARM64EC)
+
+#ifndef _MSC_VER
+#pragma intrinsic(_umul128)
+#endif
+ uint64_t product_high;
+ uint64_t const product_low = _umul128(lhs, rhs, &product_high);
+ XXH128_hash_t r128;
+ r128.low64 = product_low;
+ r128.high64 = product_high;
+ return r128;
+
+ /*
+ * MSVC for ARM64's __umulh method.
+ *
+ * This compiles to the same MUL + UMULH as GCC/Clang's __uint128_t method.
+ */
+#elif defined(_M_ARM64) || defined(_M_ARM64EC)
+
+#ifndef _MSC_VER
+#pragma intrinsic(__umulh)
+#endif
+ XXH128_hash_t r128;
+ r128.low64 = lhs * rhs;
+ r128.high64 = __umulh(lhs, rhs);
+ return r128;
+
+#else
+ /*
+ * Portable scalar method. Optimized for 32-bit and 64-bit ALUs.
+ *
+ * This is a fast and simple grade school multiply, which is shown below
+ * with base 10 arithmetic instead of base 0x100000000.
+ *
+ * 9 3 // D2 lhs = 93
+ * x 7 5 // D2 rhs = 75
+ * ----------
+ * 1 5 // D2 lo_lo = (93 % 10) * (75 % 10) = 15
+ * 4 5 | // D2 hi_lo = (93 / 10) * (75 % 10) = 45
+ * 2 1 | // D2 lo_hi = (93 % 10) * (75 / 10) = 21
+ * + 6 3 | | // D2 hi_hi = (93 / 10) * (75 / 10) = 63
+ * ---------
+ * 2 7 | // D2 cross = (15 / 10) + (45 % 10) + 21 = 27
+ * + 6 7 | | // D2 upper = (27 / 10) + (45 / 10) + 63 = 67
+ * ---------
+ * 6 9 7 5 // D4 res = (27 * 10) + (15 % 10) + (67 * 100) = 6975
+ *
+ * The reasons for adding the products like this are:
+ * 1. It avoids manual carry tracking. Just like how
+ * (9 * 9) + 9 + 9 = 99, the same applies with this for UINT64_MAX.
+ * This avoids a lot of complexity.
+ *
+ * 2. It hints for, and on Clang, compiles to, the powerful UMAAL
+ * instruction available in ARM's Digital Signal Processing extension
+ * in 32-bit ARMv6 and later, which is shown below:
+ *
+ * void UMAAL(xxh_u32 *RdLo, xxh_u32 *RdHi, xxh_u32 Rn, xxh_u32 Rm)
+ * {
+ * uint64_t product = (uint64_t)*RdLo * (uint64_t)*RdHi + Rn + Rm;
+ * *RdLo = (xxh_u32)(product & 0xFFFFFFFF);
+ * *RdHi = (xxh_u32)(product >> 32);
+ * }
+ *
+ * This instruction was designed for efficient long multiplication, and
+ * allows this to be calculated in only 4 instructions at speeds
+ * comparable to some 64-bit ALUs.
+ *
+ * 3. It isn't terrible on other platforms. Usually this will be a couple
+ * of 32-bit ADD/ADCs.
+ */
+
+ /* First calculate all of the cross products. */
+ uint64_t const lo_lo = XXH_mult32to64(lhs & 0xFFFFFFFF, rhs & 0xFFFFFFFF);
+ uint64_t const hi_lo = XXH_mult32to64(lhs >> 32, rhs & 0xFFFFFFFF);
+ uint64_t const lo_hi = XXH_mult32to64(lhs & 0xFFFFFFFF, rhs >> 32);
+ uint64_t const hi_hi = XXH_mult32to64(lhs >> 32, rhs >> 32);
+
+ /* Now add the products together. These will never overflow. */
+ uint64_t const cross = (lo_lo >> 32) + (hi_lo & 0xFFFFFFFF) + lo_hi;
+ uint64_t const upper = (hi_lo >> 32) + (cross >> 32) + hi_hi;
+ uint64_t const lower = (cross << 32) | (lo_lo & 0xFFFFFFFF);
+
+ XXH128_hash_t r128;
+ r128.low64 = lower;
+ r128.high64 = upper;
+ return r128;
+#endif
+}
+
+/*! Seems to produce slightly better code on GCC for some reason. */
+LLVM_ATTRIBUTE_ALWAYS_INLINE constexpr uint64_t XXH_xorshift64(uint64_t v64,
+ int shift) {
+ return v64 ^ (v64 >> shift);
+}
+
+LLVM_ATTRIBUTE_ALWAYS_INLINE static XXH128_hash_t
+XXH3_len_1to3_128b(const uint8_t *input, size_t len, const uint8_t *secret,
+ uint64_t seed) {
+ /* A doubled version of 1to3_64b with different constants. */
+ /*
+ * len = 1: combinedl = { input[0], 0x01, input[0], input[0] }
+ * len = 2: combinedl = { input[1], 0x02, input[0], input[1] }
+ * len = 3: combinedl = { input[2], 0x03, input[0], input[1] }
+ */
+ {
+ uint8_t const c1 = input[0];
+ uint8_t const c2 = input[len >> 1];
+ uint8_t const c3 = input[len - 1];
+ uint32_t const combinedl = ((uint32_t)c1 << 16) | ((uint32_t)c2 << 24) |
+ ((uint32_t)c3 << 0) | ((uint32_t)len << 8);
+ uint32_t const combinedh = XXH_rotl32(byteswap(combinedl), 13);
+ uint64_t const bitflipl =
+ (endian::read32le(secret) ^ endian::read32le(secret + 4)) + seed;
+ uint64_t const bitfliph =
+ (endian::read32le(secret + 8) ^ endian::read32le(secret + 12)) - seed;
+ uint64_t const keyed_lo = (uint64_t)combinedl ^ bitflipl;
+ uint64_t const keyed_hi = (uint64_t)combinedh ^ bitfliph;
+ XXH128_hash_t h128;
+ h128.low64 = XXH64_avalanche(keyed_lo);
+ h128.high64 = XXH64_avalanche(keyed_hi);
+ return h128;
+ }
+}
+
+LLVM_ATTRIBUTE_ALWAYS_INLINE static XXH128_hash_t
+XXH3_len_4to8_128b(const uint8_t *input, size_t len, const uint8_t *secret,
+ uint64_t seed) {
+ seed ^= (uint64_t)byteswap((uint32_t)seed) << 32;
+ {
+ uint32_t const input_lo = endian::read32le(input);
+ uint32_t const input_hi = endian::read32le(input + len - 4);
+ uint64_t const input_64 = input_lo + ((uint64_t)input_hi << 32);
+ uint64_t const bitflip =
+ (endian::read64le(secret + 16) ^ endian::read64le(secret + 24)) + seed;
+ uint64_t const keyed = input_64 ^ bitflip;
+
+ /* Shift len to the left to ensure it is even, this avoids even multiplies.
+ */
+ XXH128_hash_t m128 = XXH_mult64to128(keyed, PRIME64_1 + (len << 2));
+
+ m128.high64 += (m128.low64 << 1);
+ m128.low64 ^= (m128.high64 >> 3);
+
+ m128.low64 = XXH_xorshift64(m128.low64, 35);
+ m128.low64 *= PRIME_MX2;
+ m128.low64 = XXH_xorshift64(m128.low64, 28);
+ m128.high64 = XXH3_avalanche(m128.high64);
+ return m128;
+ }
+}
+
+LLVM_ATTRIBUTE_ALWAYS_INLINE static XXH128_hash_t
+XXH3_len_9to16_128b(const uint8_t *input, size_t len, const uint8_t *secret,
+ uint64_t seed) {
+ {
+ uint64_t const bitflipl =
+ (endian::read64le(secret + 32) ^ endian::read64le(secret + 40)) - seed;
+ uint64_t const bitfliph =
+ (endian::read64le(secret + 48) ^ endian::read64le(secret + 56)) + seed;
+ uint64_t const input_lo = endian::read64le(input);
+ uint64_t input_hi = endian::read64le(input + len - 8);
+ XXH128_hash_t m128 =
+ XXH_mult64to128(input_lo ^ input_hi ^ bitflipl, PRIME64_1);
+ /*
+ * Put len in the middle of m128 to ensure that the length gets mixed to
+ * both the low and high bits in the 128x64 multiply below.
+ */
+ m128.low64 += (uint64_t)(len - 1) << 54;
+ input_hi ^= bitfliph;
+ /*
+ * Add the high 32 bits of input_hi to the high 32 bits of m128, then
+ * add the long product of the low 32 bits of input_hi and PRIME32_2 to
+ * the high 64 bits of m128.
+ *
+ * The best approach to this operation is different on 32-bit and 64-bit.
+ */
+ if (sizeof(void *) < sizeof(uint64_t)) { /* 32-bit */
+ /*
+ * 32-bit optimized version, which is more readable.
+ *
+ * On 32-bit, it removes an ADC and delays a dependency between the two
+ * halves of m128.high64, but it generates an extra mask on 64-bit.
+ */
+ m128.high64 += (input_hi & 0xFFFFFFFF00000000ULL) +
+ XXH_mult32to64((uint32_t)input_hi, PRIME32_2);
+ } else {
+ /*
+ * 64-bit optimized (albeit more confusing) version.
+ *
+ * Uses some properties of addition and multiplication to remove the mask:
+ *
+ * Let:
+ * a = input_hi.lo = (input_hi & 0x00000000FFFFFFFF)
+ * b = input_hi.hi = (input_hi & 0xFFFFFFFF00000000)
+ * c = PRIME32_2
+ *
+ * a + (b * c)
+ * Inverse Property: x + y - x == y
+ * a + (b * (1 + c - 1))
+ * Distributive Property: x * (y + z) == (x * y) + (x * z)
+ * a + (b * 1) + (b * (c - 1))
+ * Identity Property: x * 1 == x
+ * a + b + (b * (c - 1))
+ *
+ * Substitute a, b, and c:
+ * input_hi.hi + input_hi.lo + ((uint64_t)input_hi.lo * (PRIME32_2
+ * - 1))
+ *
+ * Since input_hi.hi + input_hi.lo == input_hi, we get this:
+ * input_hi + ((uint64_t)input_hi.lo * (PRIME32_2 - 1))
+ */
+ m128.high64 +=
+ input_hi + XXH_mult32to64((uint32_t)input_hi, PRIME32_2 - 1);
+ }
+ /* m128 ^= XXH_swap64(m128 >> 64); */
+ m128.low64 ^= byteswap(m128.high64);
+
+ { /* 128x64 multiply: h128 = m128 * PRIME64_2; */
+ XXH128_hash_t h128 = XXH_mult64to128(m128.low64, PRIME64_2);
+ h128.high64 += m128.high64 * PRIME64_2;
+
+ h128.low64 = XXH3_avalanche(h128.low64);
+ h128.high64 = XXH3_avalanche(h128.high64);
+ return h128;
+ }
+ }
+}
+
+/*
+ * Assumption: `secret` size is >= XXH3_SECRET_SIZE_MIN
+ */
+LLVM_ATTRIBUTE_ALWAYS_INLINE static XXH128_hash_t
+XXH3_len_0to16_128b(const uint8_t *input, size_t len, const uint8_t *secret,
+ uint64_t seed) {
+ {
+ if (len > 8)
+ return XXH3_len_9to16_128b(input, len, secret, seed);
+ if (len >= 4)
+ return XXH3_len_4to8_128b(input, len, secret, seed);
+ if (len)
+ return XXH3_len_1to3_128b(input, len, secret, seed);
+ {
+ XXH128_hash_t h128;
+ uint64_t const bitflipl =
+ endian::read64le(secret + 64) ^ endian::read64le(secret + 72);
+ uint64_t const bitfliph =
+ endian::read64le(secret + 80) ^ endian::read64le(secret + 88);
+ h128.low64 = XXH64_avalanche(seed ^ bitflipl);
+ h128.high64 = XXH64_avalanche(seed ^ bitfliph);
+ return h128;
+ }
+ }
+}
+
+/*
+ * A bit slower than XXH3_mix16B, but handles multiply by zero better.
+ */
+LLVM_ATTRIBUTE_ALWAYS_INLINE static XXH128_hash_t
+XXH128_mix32B(XXH128_hash_t acc, const uint8_t *input_1, const uint8_t *input_2,
+ const uint8_t *secret, uint64_t seed) {
+ acc.low64 += XXH3_mix16B(input_1, secret + 0, seed);
+ acc.low64 ^= endian::read64le(input_2) + endian::read64le(input_2 + 8);
+ acc.high64 += XXH3_mix16B(input_2, secret + 16, seed);
+ acc.high64 ^= endian::read64le(input_1) + endian::read64le(input_1 + 8);
+ return acc;
+}
+
+LLVM_ATTRIBUTE_ALWAYS_INLINE static XXH128_hash_t
+XXH3_len_17to128_128b(const uint8_t *input, size_t len, const uint8_t *secret,
+ size_t secretSize, uint64_t seed) {
+ (void)secretSize;
+
+ {
+ XXH128_hash_t acc;
+ acc.low64 = len * PRIME64_1;
+ acc.high64 = 0;
+
+#if XXH_SIZE_OPT >= 1
+ {
+ /* Smaller, but slightly slower. */
+ unsigned int i = (unsigned int)(len - 1) / 32;
+ do {
+ acc = XXH128_mix32B(acc, input + 16 * i, input + len - 16 * (i + 1),
+ secret + 32 * i, seed);
+ } while (i-- != 0);
+ }
+#else
+ if (len > 32) {
+ if (len > 64) {
+ if (len > 96) {
+ acc = XXH128_mix32B(acc, input + 48, input + len - 64, secret + 96,
+ seed);
+ }
+ acc =
+ XXH128_mix32B(acc, input + 32, input + len - 48, secret + 64, seed);
+ }
+ acc = XXH128_mix32B(acc, input + 16, input + len - 32, secret + 32, seed);
+ }
+ acc = XXH128_mix32B(acc, input, input + len - 16, secret, seed);
+#endif
+ {
+ XXH128_hash_t h128;
+ h128.low64 = acc.low64 + acc.high64;
+ h128.high64 = (acc.low64 * PRIME64_1) + (acc.high64 * PRIME64_4) +
+ ((len - seed) * PRIME64_2);
+ h128.low64 = XXH3_avalanche(h128.low64);
+ h128.high64 = (uint64_t)0 - XXH3_avalanche(h128.high64);
+ return h128;
+ }
+ }
+}
+
+LLVM_ATTRIBUTE_NOINLINE static XXH128_hash_t
+XXH3_len_129to240_128b(const uint8_t *input, size_t len, const uint8_t *secret,
+ size_t secretSize, uint64_t seed) {
+ (void)secretSize;
+
+ {
+ XXH128_hash_t acc;
+ unsigned i;
+ acc.low64 = len * PRIME64_1;
+ acc.high64 = 0;
+ /*
+ * We set as `i` as offset + 32. We do this so that unchanged
+ * `len` can be used as upper bound. This reaches a sweet spot
+ * where both x86 and aarch64 get simple agen and good codegen
+ * for the loop.
+ */
+ for (i = 32; i < 160; i += 32) {
+ acc = XXH128_mix32B(acc, input + i - 32, input + i - 16, secret + i - 32,
+ seed);
+ }
+ acc.low64 = XXH3_avalanche(acc.low64);
+ acc.high64 = XXH3_avalanche(acc.high64);
+ /*
+ * NB: `i <= len` will duplicate the last 32-bytes if
+ * len % 32 was zero. This is an unfortunate necessity to keep
+ * the hash result stable.
+ */
+ for (i = 160; i <= len; i += 32) {
+ acc = XXH128_mix32B(acc, input + i - 32, input + i - 16,
+ secret + XXH3_MIDSIZE_STARTOFFSET + i - 160, seed);
+ }
+ /* last bytes */
+ acc = XXH128_mix32B(acc, input + len - 16, input + len - 32,
+ secret + XXH3_SECRETSIZE_MIN - XXH3_MIDSIZE_LASTOFFSET -
+ 16,
+ (uint64_t)0 - seed);
+
+ {
+ XXH128_hash_t h128;
+ h128.low64 = acc.low64 + acc.high64;
+ h128.high64 = (acc.low64 * PRIME64_1) + (acc.high64 * PRIME64_4) +
+ ((len - seed) * PRIME64_2);
+ h128.low64 = XXH3_avalanche(h128.low64);
+ h128.high64 = (uint64_t)0 - XXH3_avalanche(h128.high64);
+ return h128;
+ }
+ }
+}
+
+LLVM_ATTRIBUTE_ALWAYS_INLINE XXH128_hash_t
+XXH3_hashLong_128b(const uint8_t *input, size_t len, const uint8_t *secret,
+ size_t secretSize) {
+ const size_t nbStripesPerBlock =
+ (secretSize - XXH_STRIPE_LEN) / XXH_SECRET_CONSUME_RATE;
+ const size_t block_len = XXH_STRIPE_LEN * nbStripesPerBlock;
+ const size_t nb_blocks = (len - 1) / block_len;
+ alignas(16) uint64_t acc[XXH_ACC_NB] = {
+ PRIME32_3, PRIME64_1, PRIME64_2, PRIME64_3,
+ PRIME64_4, PRIME32_2, PRIME64_5, PRIME32_1,
+ };
+
+ for (size_t n = 0; n < nb_blocks; ++n) {
+ XXH3_accumulate_scalar(acc, input + n * block_len, secret,
+ nbStripesPerBlock);
+ XXH3_scrambleAcc(acc, secret + secretSize - XXH_STRIPE_LEN);
+ }
+
+ /* last partial block */
+ const size_t nbStripes = (len - 1 - (block_len * nb_blocks)) / XXH_STRIPE_LEN;
+ assert(nbStripes <= secretSize / XXH_SECRET_CONSUME_RATE);
+ XXH3_accumulate_scalar(acc, input + nb_blocks * block_len, secret, nbStripes);
+
+ /* last stripe */
+ constexpr size_t XXH_SECRET_LASTACC_START = 7;
+ XXH3_accumulate_512_scalar(acc, input + len - XXH_STRIPE_LEN,
+ secret + secretSize - XXH_STRIPE_LEN -
+ XXH_SECRET_LASTACC_START);
+
+ /* converge into final hash */
+ static_assert(sizeof(acc) == 64);
+ XXH128_hash_t h128;
+ constexpr size_t XXH_SECRET_MERGEACCS_START = 11;
+ h128.low64 = XXH3_mergeAccs(acc, secret + XXH_SECRET_MERGEACCS_START,
+ (uint64_t)len * PRIME64_1);
+ h128.high64 = XXH3_mergeAccs(
+ acc, secret + secretSize - sizeof(acc) - XXH_SECRET_MERGEACCS_START,
+ ~((uint64_t)len * PRIME64_2));
+ return h128;
+}
+
+llvm::XXH128_hash_t llvm::xxh3_128bits(ArrayRef<uint8_t> data) {
+ size_t len = data.size();
+ const uint8_t *input = data.data();
+
+ /*
+ * If an action is to be taken if `secret` conditions are not respected,
+ * it should be done here.
+ * For now, it's a contract pre-condition.
+ * Adding a check and a branch here would cost performance at every hash.
+ */
+ if (len <= 16)
+ return XXH3_len_0to16_128b(input, len, kSecret, /*seed64=*/0);
+ if (len <= 128)
+ return XXH3_len_17to128_128b(input, len, kSecret, sizeof(kSecret),
+ /*seed64=*/0);
+ if (len <= XXH3_MIDSIZE_MAX)
+ return XXH3_len_129to240_128b(input, len, kSecret, sizeof(kSecret),
+ /*seed64=*/0);
+ return XXH3_hashLong_128b(input, len, kSecret, sizeof(kSecret));
+}
diff --git a/llvm/unittests/Support/xxhashTest.cpp b/llvm/unittests/Support/xxhashTest.cpp
index 7d78de6772b51..84308ce130e72 100644
--- a/llvm/unittests/Support/xxhashTest.cpp
+++ b/llvm/unittests/Support/xxhashTest.cpp
@@ -11,6 +11,26 @@
using namespace llvm;
+/* use #define to make them constant, required for initialization */
+#define PRIME32 2654435761U
+#define PRIME64 11400714785074694797ULL
+
+/*
+ * Fills a test buffer with pseudorandom data.
+ *
+ * This is used in the sanity check - its values must not be changed.
+ */
+static void fillTestBuffer(uint8_t *buffer, size_t len) {
+ uint64_t byteGen = PRIME32;
+
+ assert(buffer != NULL);
+
+ for (size_t i = 0; i < len; i++) {
+ buffer[i] = (uint8_t)(byteGen >> 56);
+ byteGen *= PRIME64;
+ }
+}
+
TEST(xxhashTest, Basic) {
EXPECT_EQ(0xef46db3751d8e999U, xxHash64(StringRef()));
EXPECT_EQ(0x33bf00a859c4ba3fU, xxHash64("foo"));
@@ -61,3 +81,52 @@ TEST(xxhashTest, xxh3) {
F(2243, 0x0979f786a24edde7);
#undef F
}
+
+TEST(xxhashTest, xxh3_128bits) {
+#define SANITY_BUFFER_SIZE 2367
+ uint8_t sanityBuffer[SANITY_BUFFER_SIZE];
+
+ fillTestBuffer(sanityBuffer, sizeof(sanityBuffer));
+
+#define F(len, expected) \
+ EXPECT_EQ(XXH128_hash_t(expected), \
+ xxh3_128bits(ArrayRef(sanityBuffer, size_t(len))))
+
+ F(0, (XXH128_hash_t{0x6001C324468D497FULL,
+ 0x99AA06D3014798D8ULL})); /* empty string */
+ F(1, (XXH128_hash_t{0xC44BDFF4074EECDBULL,
+ 0xA6CD5E9392000F6AULL})); /* 1 - 3 */
+ F(6, (XXH128_hash_t{0x3E7039BDDA43CFC6ULL,
+ 0x082AFE0B8162D12AULL})); /* 4 - 8 */
+ F(12, (XXH128_hash_t{0x061A192713F69AD9ULL,
+ 0x6E3EFD8FC7802B18ULL})); /* 9 - 16 */
+ F(24, (XXH128_hash_t{0x1E7044D28B1B901DULL,
+ 0x0CE966E4678D3761ULL})); /* 17 - 32 */
+ F(48, (XXH128_hash_t{0xF942219AED80F67BULL,
+ 0xA002AC4E5478227EULL})); /* 33 - 64 */
+ F(81, (XXH128_hash_t{0x5E8BAFB9F95FB803ULL,
+ 0x4952F58181AB0042ULL})); /* 65 - 96 */
+ F(222, (XXH128_hash_t{0xF1AEBD597CEC6B3AULL,
+ 0x337E09641B948717ULL})); /* 129-240 */
+ F(403,
+ (XXH128_hash_t{
+ 0xCDEB804D65C6DEA4ULL,
+ 0x1B6DE21E332DD73DULL})); /* one block, last stripe is overlapping */
+ F(512,
+ (XXH128_hash_t{
+ 0x617E49599013CB6BULL,
+ 0x18D2D110DCC9BCA1ULL})); /* one block, finishing at stripe boundary */
+ F(2048,
+ (XXH128_hash_t{
+ 0xDD59E2C3A5F038E0ULL,
+ 0xF736557FD47073A5ULL})); /* 2 blocks, finishing at block boundary */
+ F(2240,
+ (XXH128_hash_t{
+ 0x6E73A90539CF2948ULL,
+ 0xCCB134FBFA7CE49DULL})); /* 3 blocks, finishing at stripe boundary */
+ F(2367,
+ (XXH128_hash_t{
+ 0xCB37AEB9E5D361EDULL,
+ 0xE89C0F6FF369B427ULL})); /* 3 blocks, last stripe is overlapping */
+#undef F
+}
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