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-rw-r--r--src/liblzma/check/crc64_fast.c446
1 files changed, 32 insertions, 414 deletions
diff --git a/src/liblzma/check/crc64_fast.c b/src/liblzma/check/crc64_fast.c
index 0c8622a..0ce83fe 100644
--- a/src/liblzma/check/crc64_fast.c
+++ b/src/liblzma/check/crc64_fast.c
@@ -1,85 +1,30 @@
+// SPDX-License-Identifier: 0BSD
+
///////////////////////////////////////////////////////////////////////////////
//
/// \file crc64.c
/// \brief CRC64 calculation
-///
-/// There are two methods in this file. crc64_generic uses the
-/// the slice-by-four algorithm. This is the same idea that is
-/// used in crc32_fast.c, but for CRC64 we use only four tables
-/// instead of eight to avoid increasing CPU cache usage.
-///
-/// crc64_clmul uses 32/64-bit x86 SSSE3, SSE4.1, and CLMUL instructions.
-/// It was derived from
-/// https://www.intel.com/content/dam/www/public/us/en/documents/white-papers/fast-crc-computation-generic-polynomials-pclmulqdq-paper.pdf
-/// and the public domain code from https://github.com/rawrunprotected/crc
-/// (URLs were checked on 2022-11-07).
-///
-/// FIXME: Builds for 32-bit x86 use crc64_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 crc64_table.c since it doesn't know that assembly
-/// code has been disabled.
//
// Authors: Lasse Collin
// Ilya Kurdyukov
//
-// This file has been put into the public domain.
-// You can do whatever you want with this file.
-//
///////////////////////////////////////////////////////////////////////////////
#include "check.h"
+#include "crc_common.h"
-#undef CRC_GENERIC
-#undef CRC_CLMUL
-#undef CRC_USE_GENERIC_FOR_SMALL_INPUTS
-
-// If CLMUL cannot be used then only the generic slice-by-four is built.
-#if !defined(HAVE_USABLE_CLMUL)
-# define CRC_GENERIC 1
-
-// If CLMUL is allowed unconditionally in the compiler options then the
-// generic version can be omitted. Note that this doesn't work with MSVC
-// as I don't know how to detect the features here.
-//
-// NOTE: Keep this this in sync with crc64_table.c.
-#elif (defined(__SSSE3__) && defined(__SSE4_1__) && defined(__PCLMUL__)) \
- || (defined(__e2k__) && __iset__ >= 6)
-# define CRC_CLMUL 1
-
-// Otherwise build both and detect at runtime which version to use.
-#else
-# define CRC_GENERIC 1
-# define CRC_CLMUL 1
-
-/*
- // The generic code is much faster with 1-8-byte inputs and has
- // similar performance up to 16 bytes at least in microbenchmarks
- // (it depends on input buffer alignment too). If both versions are
- // built, this #define will use the generic version for inputs up to
- // 16 bytes and CLMUL for bigger inputs. It saves a little in code
- // size since the special cases for 0-16-byte inputs will be omitted
- // from the CLMUL code.
-# define CRC_USE_GENERIC_FOR_SMALL_INPUTS 1
-*/
-
-# if defined(_MSC_VER)
-# include <intrin.h>
-# elif defined(HAVE_CPUID_H)
-# include <cpuid.h>
-# endif
+#if defined(CRC_X86_CLMUL)
+# define BUILDING_CRC64_CLMUL
+# include "crc_x86_clmul.h"
#endif
+#ifdef CRC64_GENERIC
+
/////////////////////////////////
// Generic slice-by-four CRC64 //
/////////////////////////////////
-#ifdef CRC_GENERIC
-
-#include "crc_macros.h"
-
-
#ifdef WORDS_BIGENDIAN
# define A1(x) ((x) >> 56)
#else
@@ -94,7 +39,7 @@ crc64_generic(const uint8_t *buf, size_t size, uint64_t crc)
crc = ~crc;
#ifdef WORDS_BIGENDIAN
- crc = bswap64(crc);
+ crc = byteswap64(crc);
#endif
if (size > 4) {
@@ -128,7 +73,7 @@ crc64_generic(const uint8_t *buf, size_t size, uint64_t crc)
crc = lzma_crc64_table[0][*buf++ ^ A1(crc)] ^ S8(crc);
#ifdef WORDS_BIGENDIAN
- crc = bswap64(crc);
+ crc = byteswap64(crc);
#endif
return ~crc;
@@ -136,336 +81,40 @@ crc64_generic(const uint8_t *buf, size_t size, uint64_t crc)
#endif
-/////////////////////
-// x86 CLMUL CRC64 //
-/////////////////////
-
-#ifdef CRC_CLMUL
-
-#include <immintrin.h>
-
-
-/*
-// These functions were used to generate the constants
-// at the top of crc64_clmul().
-static uint64_t
-calc_lo(uint64_t poly)
-{
- uint64_t a = poly;
- uint64_t b = 0;
-
- for (unsigned i = 0; i < 64; ++i) {
- b = (b >> 1) | (a << 63);
- a = (a >> 1) ^ (a & 1 ? poly : 0);
- }
-
- return b;
-}
-
-static uint64_t
-calc_hi(uint64_t poly, uint64_t a)
-{
- for (unsigned i = 0; i < 64; ++i)
- a = (a >> 1) ^ (a & 1 ? poly : 0);
-
- return a;
-}
-*/
-
-
-#define MASK_L(in, mask, r) \
- r = _mm_shuffle_epi8(in, mask)
-
-#define MASK_H(in, mask, r) \
- r = _mm_shuffle_epi8(in, _mm_xor_si128(mask, vsign))
-
-#define MASK_LH(in, mask, low, high) \
- MASK_L(in, mask, low); \
- MASK_H(in, mask, high)
-
-
-// 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
-// The intrinsics use 16-byte-aligned reads from buf, thus they may read
-// up to 15 bytes before or after the buffer (depending on the alignment
-// of the buf argument). The values of the extra bytes are ignored.
-// This unavoidably trips -fsanitize=address so address sanitizier has
-// to be disabled for this function.
-#if lzma_has_attribute(__no_sanitize_address__)
-__attribute__((__no_sanitize_address__))
-#endif
-static uint64_t
-crc64_clmul(const uint8_t *buf, size_t size, uint64_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
-
- // const uint64_t poly = 0xc96c5795d7870f42; // CRC polynomial
- const uint64_t p = 0x92d8af2baf0e1e85; // (poly << 1) | 1
- const uint64_t mu = 0x9c3e466c172963d5; // (calc_lo(poly) << 1) | 1
- const uint64_t k2 = 0xdabe95afc7875f40; // calc_hi(poly, 1)
- const uint64_t k1 = 0xe05dd497ca393ae4; // calc_hi(poly, k2)
- const __m128i vfold0 = _mm_set_epi64x(p, mu);
- const __m128i vfold1 = _mm_set_epi64x(k2, k1);
-
- // Create a vector with 8-bit values 0 to 15. This is used to
- // construct control masks for _mm_blendv_epi8 and _mm_shuffle_epi8.
- const __m128i vramp = _mm_setr_epi32(
- 0x03020100, 0x07060504, 0x0b0a0908, 0x0f0e0d0c);
-
- // This is used to inverse the control mask of _mm_shuffle_epi8
- // so that bytes that wouldn't be picked with the original mask
- // will be picked and vice versa.
- const __m128i vsign = _mm_set1_epi8(0x80);
-
- // Memory addresses A to D and the distances between them:
- //
- // A B C D
- // [skip_start][size][skip_end]
- // [ size2 ]
- //
- // A and D are 16-byte aligned. B and C are 1-byte aligned.
- // skip_start and skip_end are 0-15 bytes. size is at least 1 byte.
- //
- // A = aligned_buf will initially point to this address.
- // B = The address pointed by the caller-supplied buf.
- // C = buf + size == aligned_buf + size2
- // D = buf + size + skip_end == aligned_buf + size2 + skip_end
- const size_t skip_start = (size_t)((uintptr_t)buf & 15);
- const size_t skip_end = (size_t)((0U - (uintptr_t)(buf + size)) & 15);
- const __m128i *aligned_buf = (const __m128i *)(
- (uintptr_t)buf & ~(uintptr_t)15);
-
- // If size2 <= 16 then the whole input fits into a single 16-byte
- // vector. If size2 > 16 then at least two 16-byte vectors must
- // be processed. If size2 > 16 && size <= 16 then there is only
- // one 16-byte vector's worth of input but it is unaligned in memory.
- //
- // NOTE: There is no integer overflow here if the arguments are valid.
- // If this overflowed, buf + size would too.
- size_t size2 = skip_start + size;
-
- // Masks to be used with _mm_blendv_epi8 and _mm_shuffle_epi8:
- // The first skip_start or skip_end bytes in the vectors will have
- // the high bit (0x80) set. _mm_blendv_epi8 and _mm_shuffle_epi8
- // will produce zeros for these positions. (Bitwise-xor of these
- // masks with vsign will produce the opposite behavior.)
- const __m128i mask_start
- = _mm_sub_epi8(vramp, _mm_set1_epi8(skip_start));
- const __m128i mask_end = _mm_sub_epi8(vramp, _mm_set1_epi8(skip_end));
-
- // Get the first 1-16 bytes into data0. If loading less than 16 bytes,
- // the bytes are loaded to the high bits of the vector and the least
- // significant positions are filled with zeros.
- const __m128i data0 = _mm_blendv_epi8(_mm_load_si128(aligned_buf),
- _mm_setzero_si128(), mask_start);
- ++aligned_buf;
-
-#if defined(__i386__) || defined(_M_IX86)
- const __m128i initial_crc = _mm_set_epi64x(0, ~crc);
-#else
- // GCC and Clang would produce good code with _mm_set_epi64x
- // but MSVC needs _mm_cvtsi64_si128 on x86-64.
- const __m128i initial_crc = _mm_cvtsi64_si128(~crc);
-#endif
+#if defined(CRC64_GENERIC) && defined(CRC64_ARCH_OPTIMIZED)
- __m128i v0, v1, v2, v3;
-
-#ifndef CRC_USE_GENERIC_FOR_SMALL_INPUTS
- if (size <= 16) {
- // Right-shift initial_crc by 1-16 bytes based on "size"
- // and store the result in v1 (high bytes) and v0 (low bytes).
- //
- // NOTE: The highest 8 bytes of initial_crc are zeros so
- // v1 will be filled with zeros if size >= 8. The highest 8
- // bytes of v1 will always become zeros.
- //
- // [ v1 ][ v0 ]
- // [ initial_crc ] size == 1
- // [ initial_crc ] size == 2
- // [ initial_crc ] size == 15
- // [ initial_crc ] size == 16 (all in v0)
- const __m128i mask_low = _mm_add_epi8(
- vramp, _mm_set1_epi8(size - 16));
- MASK_LH(initial_crc, mask_low, v0, v1);
-
- if (size2 <= 16) {
- // There are 1-16 bytes of input and it is all
- // in data0. Copy the input bytes to v3. If there
- // are fewer than 16 bytes, the low bytes in v3
- // will be filled with zeros. That is, the input
- // bytes are stored to the same position as
- // (part of) initial_crc is in v0.
- MASK_L(data0, mask_end, v3);
- } else {
- // There are 2-16 bytes of input but not all bytes
- // are in data0.
- const __m128i data1 = _mm_load_si128(aligned_buf);
-
- // Collect the 2-16 input bytes from data0 and data1
- // to v2 and v3, and bitwise-xor them with the
- // low bits of initial_crc in v0. Note that the
- // the second xor is below this else-block as it
- // is shared with the other branch.
- MASK_H(data0, mask_end, v2);
- MASK_L(data1, mask_end, v3);
- v0 = _mm_xor_si128(v0, v2);
- }
+//////////////////////////
+// Function dispatching //
+//////////////////////////
- v0 = _mm_xor_si128(v0, v3);
- v1 = _mm_alignr_epi8(v1, v0, 8);
- } else
-#endif
- {
- const __m128i data1 = _mm_load_si128(aligned_buf);
- MASK_LH(initial_crc, mask_start, v0, v1);
- v0 = _mm_xor_si128(v0, data0);
- v1 = _mm_xor_si128(v1, data1);
-
-#define FOLD \
- v1 = _mm_xor_si128(v1, _mm_clmulepi64_si128(v0, vfold1, 0x00)); \
- v0 = _mm_xor_si128(v1, _mm_clmulepi64_si128(v0, vfold1, 0x11));
-
- while (size2 > 32) {
- ++aligned_buf;
- size2 -= 16;
- FOLD
- v1 = _mm_load_si128(aligned_buf);
- }
-
- if (size2 < 32) {
- MASK_H(v0, mask_end, v2);
- MASK_L(v0, mask_end, v0);
- MASK_L(v1, mask_end, v3);
- v1 = _mm_or_si128(v2, v3);
- }
-
- FOLD
- v1 = _mm_srli_si128(v0, 8);
-#undef FOLD
- }
+// If both the generic and arch-optimized implementations are usable, then
+// the function that is used is selected at runtime. See crc32_fast.c.
- v1 = _mm_xor_si128(_mm_clmulepi64_si128(v0, vfold1, 0x10), v1);
- v0 = _mm_clmulepi64_si128(v1, vfold0, 0x00);
- v2 = _mm_clmulepi64_si128(v0, vfold0, 0x10);
- v0 = _mm_xor_si128(_mm_xor_si128(v2, _mm_slli_si128(v0, 8)), v1);
+typedef uint64_t (*crc64_func_type)(
+ const uint8_t *buf, size_t size, uint64_t crc);
-#if defined(__i386__) || defined(_M_IX86)
- return ~(((uint64_t)(uint32_t)_mm_extract_epi32(v0, 3) << 32) |
- (uint64_t)(uint32_t)_mm_extract_epi32(v0, 2));
-#else
- return ~(uint64_t)_mm_extract_epi64(v0, 1);
-#endif
-
-#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
-
-
-////////////////////////
-// Detect CPU support //
-////////////////////////
-
-#if defined(CRC_GENERIC) && defined(CRC_CLMUL)
-static inline bool
-is_clmul_supported(void)
+static crc64_func_type
+crc64_resolve(void)
{
- int success = 1;
- uint32_t r[4]; // eax, ebx, ecx, edx
-
-#if defined(_MSC_VER)
- // This needs <intrin.h> with MSVC. ICC has it as a built-in
- // on all platforms.
- __cpuid(r, 1);
-#elif defined(HAVE_CPUID_H)
- // Compared to just using __asm__ to run CPUID, this also checks
- // that CPUID is supported and saves and restores ebx as that is
- // needed with GCC < 5 with position-independent code (PIC).
- success = __get_cpuid(1, &r[0], &r[1], &r[2], &r[3]);
-#else
- // Just a fallback that shouldn't be needed.
- __asm__("cpuid\n\t"
- : "=a"(r[0]), "=b"(r[1]), "=c"(r[2]), "=d"(r[3])
- : "a"(1), "c"(0));
-#endif
-
- // Returns true if these are supported:
- // CLMUL (bit 1 in ecx)
- // SSSE3 (bit 9 in ecx)
- // SSE4.1 (bit 19 in ecx)
- const uint32_t ecx_mask = (1 << 1) | (1 << 9) | (1 << 19);
- return success && (r[2] & ecx_mask) == ecx_mask;
-
- // Alternative methods that weren't used:
- // - ICC's _may_i_use_cpu_feature: the other methods should work too.
- // - GCC >= 6 / Clang / ICX __builtin_cpu_supports("pclmul")
- //
- // CPUID decding is needed with MSVC anyway and older GCC. This keeps
- // the feature checks in the build system simpler too. The nice thing
- // about __builtin_cpu_supports would be that it generates very short
- // code as is it only reads a variable set at startup but a few bytes
- // doesn't matter here.
+ return is_arch_extension_supported()
+ ? &crc64_arch_optimized : &crc64_generic;
}
-
#ifdef HAVE_FUNC_ATTRIBUTE_CONSTRUCTOR
-# define CRC64_FUNC_INIT
# define CRC64_SET_FUNC_ATTR __attribute__((__constructor__))
+static crc64_func_type crc64_func;
#else
-# define CRC64_FUNC_INIT = &crc64_dispatch
# define CRC64_SET_FUNC_ATTR
static uint64_t crc64_dispatch(const uint8_t *buf, size_t size, uint64_t crc);
+static crc64_func_type crc64_func = &crc64_dispatch;
#endif
-// Pointer to the the selected CRC64 method.
-static uint64_t (*crc64_func)(const uint8_t *buf, size_t size, uint64_t crc)
- CRC64_FUNC_INIT;
-
-
CRC64_SET_FUNC_ATTR
static void
crc64_set_func(void)
{
- crc64_func = is_clmul_supported() ? &crc64_clmul : &crc64_generic;
+ crc64_func = crc64_resolve();
return;
}
@@ -474,12 +123,6 @@ crc64_set_func(void)
static uint64_t
crc64_dispatch(const uint8_t *buf, size_t size, uint64_t crc)
{
- // When __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_crc64() but this likely
- // isn't strictly standards compliant. Let's change it if it breaks.
crc64_set_func();
return crc64_func(buf, size, crc);
}
@@ -490,47 +133,22 @@ crc64_dispatch(const uint8_t *buf, size_t size, uint64_t crc)
extern LZMA_API(uint64_t)
lzma_crc64(const uint8_t *buf, size_t size, uint64_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_crc64(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.
+#if defined(CRC64_GENERIC) && defined(CRC64_ARCH_OPTIMIZED)
+
#ifdef CRC_USE_GENERIC_FOR_SMALL_INPUTS
if (size <= 16)
return crc64_generic(buf, size, crc);
#endif
-
-/*
-#ifndef HAVE_FUNC_ATTRIBUTE_CONSTRUCTOR
- // See crc64_dispatch(). This would be the alternative which uses
- // locking and doesn't use crc64_dispatch(). Note that on Windows
- // this method needs Vista threads.
- mythread_once(crc64_set_func);
-#endif
-*/
-
return crc64_func(buf, size, crc);
-#elif defined(CRC_CLMUL)
- // If CLMUL is used unconditionally without runtime CPU detection
- // then omitting the generic version and its 8 KiB lookup table
- // makes the library smaller.
+#elif defined(CRC64_ARCH_OPTIMIZED)
+ // If arch-optimized version is used unconditionally without runtime
+ // CPU detection then omitting the generic version and its 8 KiB
+ // lookup table makes the library smaller.
//
// FIXME: Lookup table isn't currently omitted on 32-bit x86,
// see crc64_table.c.
- return crc64_clmul(buf, size, crc);
+ return crc64_arch_optimized(buf, size, crc);
#else
return crc64_generic(buf, size, crc);
generated by cgit v1.2.3 (git 2.39.1) at 2024-07-24 14:16:05 +0000