mirror of
https://git.tukaani.org/xz.git
synced 2024-04-04 12:36:23 +02:00
liblzma: Added crc32_clmul to crc32_fast.c.
This commit is contained in:
Hans Jansen
Jia Tan
parent
93e6fb08b2
commit
f1cd9d7194
2 changed files with 255 additions and 11 deletions
|
|
@ -3,13 +3,28 @@
|
|||
/// \file crc32.c
|
||||
/// \brief CRC32 calculation
|
||||
///
|
||||
/// Calculate the CRC32 using the slice-by-eight algorithm.
|
||||
/// There are two methods in this file.
|
||||
/// crc32_generic uses the slice-by-eight algorithm.
|
||||
/// It is explained in this document:
|
||||
/// http://www.intel.com/technology/comms/perfnet/download/CRC_generators.pdf
|
||||
/// The code in this file is not the same as in Intel's paper, but
|
||||
/// the basic principle is identical.
|
||||
///
|
||||
/// crc32_clmul uses 32/64-bit x86 SSSE3, SSE4.1, and CLMUL instructions.
|
||||
/// It was derived from
|
||||
/// https://www.researchgate.net/publication/263424619_Fast_CRC_computation
|
||||
/// and the public domain code from https://github.com/rawrunprotected/crc
|
||||
/// (URLs were checked on 2023-09-29).
|
||||
///
|
||||
/// FIXME: Builds for 32-bit x86 use crc32_x86.S by default instead
|
||||
/// of this file and thus CLMUL version isn't available on 32-bit x86
|
||||
/// unless configured with --disable-assembler. Even then the lookup table
|
||||
/// isn't omitted in crc32_table.c since it doesn't know that assembly
|
||||
/// code has been disabled.
|
||||
//
|
||||
// Author: Lasse Collin
|
||||
// Authors: Lasse Collin
|
||||
// Ilya Kurdyukov
|
||||
// Hans Jansen
|
||||
//
|
||||
// This file has been put into the public domain.
|
||||
// You can do whatever you want with this file.
|
||||
|
|
@ -19,12 +34,14 @@
|
|||
#include "check.h"
|
||||
#include "crc_common.h"
|
||||
|
||||
///////////////////
|
||||
// Generic CRC32 //
|
||||
///////////////////
|
||||
#ifdef CRC_GENERIC
|
||||
|
||||
// If you make any changes, do some benchmarking! Seemingly unrelated
|
||||
// changes can very easily ruin the performance (and very probably is
|
||||
// very compiler dependent).
|
||||
extern LZMA_API(uint32_t)
|
||||
lzma_crc32(const uint8_t *buf, size_t size, uint32_t crc)
|
||||
|
||||
static uint32_t
|
||||
crc32_generic(const uint8_t *buf, size_t size, uint32_t crc)
|
||||
{
|
||||
crc = ~crc;
|
||||
|
||||
|
|
@ -80,3 +97,219 @@ lzma_crc32(const uint8_t *buf, size_t size, uint32_t crc)
|
|||
|
||||
return ~crc;
|
||||
}
|
||||
#endif
|
||||
|
||||
|
||||
/////////////////////
|
||||
// x86 CLMUL CRC32 //
|
||||
/////////////////////
|
||||
|
||||
#ifdef CRC_CLMUL
|
||||
|
||||
#include <immintrin.h>
|
||||
|
||||
|
||||
/*
|
||||
// These functions were used to generate the constants
|
||||
// at the top of crc32_clmul().
|
||||
static uint64_t
|
||||
calc_lo(uint64_t p, uint64_t a, int n)
|
||||
{
|
||||
uint64_t b = 0; int i;
|
||||
for (i = 0; i < n; i++) {
|
||||
b = b >> 1 | (a & 1) << (n - 1);
|
||||
a = (a >> 1) ^ ((0 - (a & 1)) & p);
|
||||
}
|
||||
return b;
|
||||
}
|
||||
|
||||
// same as ~crc(&a, sizeof(a), ~0)
|
||||
static uint64_t
|
||||
calc_hi(uint64_t p, uint64_t a, int n)
|
||||
{
|
||||
int i;
|
||||
for (i = 0; i < n; i++)
|
||||
a = (a >> 1) ^ ((0 - (a & 1)) & p);
|
||||
return a;
|
||||
}
|
||||
*/
|
||||
|
||||
|
||||
// MSVC (VS2015 - VS2022) produces bad 32-bit x86 code from the CLMUL CRC
|
||||
// code when optimizations are enabled (release build). According to the bug
|
||||
// report, the ebx register is corrupted and the calculated result is wrong.
|
||||
// Trying to workaround the problem with "__asm mov ebx, ebx" didn't help.
|
||||
// The following pragma works and performance is still good. x86-64 builds
|
||||
// aren't affected by this problem.
|
||||
//
|
||||
// NOTE: Another pragma after the function restores the optimizations.
|
||||
// If the #if condition here is updated, the other one must be updated too.
|
||||
#if defined(_MSC_VER) && !defined(__INTEL_COMPILER) && !defined(__clang__) \
|
||||
&& defined(_M_IX86)
|
||||
# pragma optimize("g", off)
|
||||
#endif
|
||||
|
||||
// EDG-based compilers (Intel's classic compiler and compiler for E2K) can
|
||||
// define __GNUC__ but the attribute must not be used with them.
|
||||
// The new Clang-based ICX needs the attribute.
|
||||
//
|
||||
// NOTE: Build systems check for this too, keep them in sync with this.
|
||||
#if (defined(__GNUC__) || defined(__clang__)) && !defined(__EDG__)
|
||||
__attribute__((__target__("ssse3,sse4.1,pclmul")))
|
||||
#endif
|
||||
static uint32_t
|
||||
crc32_clmul(const uint8_t *buf, size_t size, uint32_t crc)
|
||||
{
|
||||
// The prototypes of the intrinsics use signed types while most of
|
||||
// the values are treated as unsigned here. These warnings in this
|
||||
// function have been checked and found to be harmless so silence them.
|
||||
#if TUKLIB_GNUC_REQ(4, 6) || defined(__clang__)
|
||||
# pragma GCC diagnostic push
|
||||
# pragma GCC diagnostic ignored "-Wsign-conversion"
|
||||
# pragma GCC diagnostic ignored "-Wconversion"
|
||||
#endif
|
||||
|
||||
#ifndef CRC_USE_GENERIC_FOR_SMALL_INPUTS
|
||||
// The code assumes that there is at least one byte of input.
|
||||
if (size == 0)
|
||||
return crc;
|
||||
#endif
|
||||
|
||||
// uint32_t poly = 0xedb88320;
|
||||
uint64_t p = 0x1db710640; // p << 1
|
||||
uint64_t mu = 0x1f7011641; // calc_lo(p, p, 32) << 1 | 1
|
||||
uint64_t k5 = 0x163cd6124; // calc_hi(p, p, 32) << 1
|
||||
uint64_t k4 = 0x0ccaa009e; // calc_hi(p, p, 64) << 1
|
||||
uint64_t k3 = 0x1751997d0; // calc_hi(p, p, 128) << 1
|
||||
|
||||
__m128i vfold4 = _mm_set_epi64x(mu, p);
|
||||
__m128i vfold8 = _mm_set_epi64x(0, k5);
|
||||
__m128i vfold16 = _mm_set_epi64x(k4, k3);
|
||||
|
||||
__m128i v0, v1, v2;
|
||||
|
||||
crc_simd_body(buf, size, &v0, &v1, vfold16, _mm_cvtsi32_si128(~crc));
|
||||
|
||||
v1 = _mm_xor_si128(
|
||||
_mm_clmulepi64_si128(v0, vfold16, 0x10), v1); // xxx0
|
||||
v2 = _mm_shuffle_epi32(v1, 0xe7); // 0xx0
|
||||
v0 = _mm_slli_epi64(v1, 32); // [0]
|
||||
v0 = _mm_clmulepi64_si128(v0, vfold8, 0x00);
|
||||
v0 = _mm_xor_si128(v0, v2); // [1] [2]
|
||||
v2 = _mm_clmulepi64_si128(v0, vfold4, 0x10);
|
||||
v2 = _mm_clmulepi64_si128(v2, vfold4, 0x00);
|
||||
v0 = _mm_xor_si128(v0, v2); // [2]
|
||||
return ~_mm_extract_epi32(v0, 2);
|
||||
|
||||
#if TUKLIB_GNUC_REQ(4, 6) || defined(__clang__)
|
||||
# pragma GCC diagnostic pop
|
||||
#endif
|
||||
}
|
||||
#if defined(_MSC_VER) && !defined(__INTEL_COMPILER) && !defined(__clang__) \
|
||||
&& defined(_M_IX86)
|
||||
# pragma optimize("", on)
|
||||
#endif
|
||||
#endif
|
||||
|
||||
#if defined(CRC_GENERIC) && defined(CRC_CLMUL)
|
||||
typedef uint32_t (*crc32_func_type)(
|
||||
const uint8_t *buf, size_t size, uint32_t crc);
|
||||
|
||||
// Clang 16.0.0 and older has a bug where it marks the ifunc resolver
|
||||
// function as unused since it is static and never used outside of
|
||||
// __attribute__((__ifunc__())).
|
||||
#if defined(HAVE_FUNC_ATTRIBUTE_IFUNC) && defined(__clang__)
|
||||
# pragma GCC diagnostic push
|
||||
# pragma GCC diagnostic ignored "-Wunused-function"
|
||||
#endif
|
||||
|
||||
static crc32_func_type
|
||||
crc32_resolve(void)
|
||||
{
|
||||
return is_clmul_supported() ? &crc32_clmul : &crc32_generic;
|
||||
}
|
||||
|
||||
#if defined(HAVE_FUNC_ATTRIBUTE_IFUNC) && defined(__clang__)
|
||||
# pragma GCC diagnostic pop
|
||||
#endif
|
||||
|
||||
#ifndef HAVE_FUNC_ATTRIBUTE_IFUNC
|
||||
|
||||
#ifdef HAVE_FUNC_ATTRIBUTE_CONSTRUCTOR
|
||||
# define CRC32_SET_FUNC_ATTR __attribute__((__constructor__))
|
||||
static crc32_func_type crc32_func;
|
||||
#else
|
||||
# define CRC32_SET_FUNC_ATTR
|
||||
static uint32_t crc32_dispatch(const uint8_t *buf, size_t size, uint32_t crc);
|
||||
static crc32_func_type crc32_func = &crc32_dispatch;
|
||||
#endif
|
||||
|
||||
CRC32_SET_FUNC_ATTR
|
||||
static void
|
||||
crc32_set_func(void)
|
||||
{
|
||||
crc32_func = crc32_resolve();
|
||||
return;
|
||||
}
|
||||
|
||||
#ifndef HAVE_FUNC_ATTRIBUTE_CONSTRUCTOR
|
||||
static uint32_t
|
||||
crc32_dispatch(const uint8_t *buf, size_t size, uint32_t crc)
|
||||
{
|
||||
// When __attribute__((__ifunc__(...))) and
|
||||
// __attribute__((__constructor__)) isn't supported, set the
|
||||
// function pointer without any locking. If multiple threads run
|
||||
// the detection code in parallel, they will all end up setting
|
||||
// the pointer to the same value. This avoids the use of
|
||||
// mythread_once() on every call to lzma_crc32() but this likely
|
||||
// isn't strictly standards compliant. Let's change it if it breaks.
|
||||
crc32_set_func();
|
||||
return crc32_func(buf, size, crc);
|
||||
}
|
||||
|
||||
#endif
|
||||
#endif
|
||||
#endif
|
||||
|
||||
|
||||
#if defined(CRC_GENERIC) && defined(CRC_CLMUL) \
|
||||
&& defined(HAVE_FUNC_ATTRIBUTE_IFUNC)
|
||||
extern LZMA_API(uint32_t)
|
||||
lzma_crc32(const uint8_t *buf, size_t size, uint32_t crc)
|
||||
__attribute__((__ifunc__("crc32_resolve")));
|
||||
#else
|
||||
extern LZMA_API(uint32_t)
|
||||
lzma_crc32(const uint8_t *buf, size_t size, uint32_t crc)
|
||||
{
|
||||
#if defined(CRC_GENERIC) && defined(CRC_CLMUL)
|
||||
// If CLMUL is available, it is the best for non-tiny inputs,
|
||||
// being over twice as fast as the generic slice-by-four version.
|
||||
// However, for size <= 16 it's different. In the extreme case
|
||||
// of size == 1 the generic version can be five times faster.
|
||||
// At size >= 8 the CLMUL starts to become reasonable. It
|
||||
// varies depending on the alignment of buf too.
|
||||
//
|
||||
// The above doesn't include the overhead of mythread_once().
|
||||
// At least on x86-64 GNU/Linux, pthread_once() is very fast but
|
||||
// it still makes lzma_crc32(buf, 1, crc) 50-100 % slower. When
|
||||
// size reaches 12-16 bytes the overhead becomes negligible.
|
||||
//
|
||||
// So using the generic version for size <= 16 may give better
|
||||
// performance with tiny inputs but if such inputs happen rarely
|
||||
// it's not so obvious because then the lookup table of the
|
||||
// generic version may not be in the processor cache.
|
||||
#ifdef CRC_USE_GENERIC_FOR_SMALL_INPUTS
|
||||
if (size <= 16)
|
||||
return crc32_generic(buf, size, crc);
|
||||
#endif
|
||||
|
||||
return crc32_func(buf, size, crc);
|
||||
|
||||
#elif defined(CRC_CLMUL)
|
||||
return crc32_clmul(buf, size, crc);
|
||||
|
||||
#else
|
||||
return crc32_generic(buf, size, crc);
|
||||
#endif
|
||||
}
|
||||
#endif
|
||||
|
|
|
|||
|
|
@ -12,11 +12,22 @@
|
|||
|
||||
#include "common.h"
|
||||
|
||||
|
||||
// FIXME: Compared to crc32_fast.c this has to check for __x86_64__ too
|
||||
// so that in 32-bit builds crc32_x86.S won't break due to a missing table.
|
||||
#if !defined(HAVE_ENCODERS) && ((defined(__x86_64__) && defined(__SSSE3__) \
|
||||
&& defined(__SSE4_1__) && defined(__PCLMUL__)) \
|
||||
|| (defined(__e2k__) && __iset__ >= 6))
|
||||
// No table needed. Use a typedef to avoid an empty translation unit.
|
||||
typedef void lzma_crc32_dummy;
|
||||
|
||||
#else
|
||||
// Having the declaration here silences clang -Wmissing-variable-declarations.
|
||||
extern const uint32_t lzma_crc32_table[8][256];
|
||||
|
||||
#ifdef WORDS_BIGENDIAN
|
||||
# include "crc32_table_be.h"
|
||||
#else
|
||||
# include "crc32_table_le.h"
|
||||
# ifdef WORDS_BIGENDIAN
|
||||
# include "crc32_table_be.h"
|
||||
# else
|
||||
# include "crc32_table_le.h"
|
||||
# endif
|
||||
#endif
|
||||
|
|
|
|||
Loading…
Reference in a new issue