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xz/src/liblzma/check/crc_common.h
Lasse Collin b5a5d9e3f7
liblzma: Disable CLMUL CRC on old MSVC targeting 32-bit x86
On GitHub runners, VS 2019 16.11 (MSVC 19.29.30158) results in
test failures. VS 2022 17.13 (MSVC 19.43.34808) works.

In xz 5.6.x there was a #pragma-based workaround for MSVC builds for
32-bit x86. Another method was thought to work with the new rewritten
CLMUL CRC. Apparently it doesn't. Keep it simple and disable CLMUL CRC
with any non-recent MSVC when building for 32-bit x86.

Fixes: 54eaea5ea49b ("liblzma: x86 CLMUL CRC: Rewrite")
Fixes: https://github.com/tukaani-project/xz/issues/171
Reported-by: Andrew Murray
2025-04-07 22:36:58 +03:00

181 lines
5.0 KiB
C

// SPDX-License-Identifier: 0BSD
///////////////////////////////////////////////////////////////////////////////
//
/// \file crc_common.h
/// \brief Macros and declarations for CRC32 and CRC64
//
// Authors: Lasse Collin
// Ilya Kurdyukov
// Jia Tan
//
///////////////////////////////////////////////////////////////////////////////
#ifndef LZMA_CRC_COMMON_H
#define LZMA_CRC_COMMON_H
#include "common.h"
/////////////
// Generic //
/////////////
#ifdef WORDS_BIGENDIAN
# define A(x) ((x) >> 24)
# define B(x) (((x) >> 16) & 0xFF)
# define C(x) (((x) >> 8) & 0xFF)
# define D(x) ((x) & 0xFF)
# define S8(x) ((x) << 8)
# define S32(x) ((x) << 32)
#else
# define A(x) ((x) & 0xFF)
# define B(x) (((x) >> 8) & 0xFF)
# define C(x) (((x) >> 16) & 0xFF)
# define D(x) ((x) >> 24)
# define S8(x) ((x) >> 8)
# define S32(x) ((x) >> 32)
#endif
/// lzma_crc32_table[0] is needed by LZ encoder so we need to keep
/// the array two-dimensional.
#ifdef HAVE_SMALL
lzma_attr_visibility_hidden
extern uint32_t lzma_crc32_table[1][256];
extern void lzma_crc32_init(void);
#else
lzma_attr_visibility_hidden
extern const uint32_t lzma_crc32_table[8][256];
lzma_attr_visibility_hidden
extern const uint64_t lzma_crc64_table[4][256];
#endif
///////////////////
// Configuration //
///////////////////
// NOTE: This config isn't used if HAVE_SMALL is defined!
// These are defined if the generic slicing-by-n implementations and their
// lookup tables are built.
#undef CRC32_GENERIC
#undef CRC64_GENERIC
// These are defined if an arch-specific version is built. If both this
// and matching _GENERIC is defined then runtime detection must be used.
#undef CRC32_ARCH_OPTIMIZED
#undef CRC64_ARCH_OPTIMIZED
// The x86 CLMUL is used for both CRC32 and CRC64.
#undef CRC_X86_CLMUL
// Many ARM64 processor have CRC32 instructions.
// CRC64 could be done with CLMUL but it's not implemented yet.
#undef CRC32_ARM64
// 64-bit LoongArch has CRC32 instructions.
#undef CRC32_LOONGARCH
// ARM64
//
// Keep this in sync with changes to crc32_arm64.h
#if defined(_WIN32) || defined(HAVE_GETAUXVAL) \
|| defined(HAVE_ELF_AUX_INFO) \
|| (defined(__APPLE__) && defined(HAVE_SYSCTLBYNAME))
# define CRC_ARM64_RUNTIME_DETECTION 1
#endif
// ARM64 CRC32 instruction is only useful for CRC32. Currently, only
// little endian is supported since we were unable to test on a big
// endian machine.
#if defined(HAVE_ARM64_CRC32) && !defined(WORDS_BIGENDIAN)
// Allow ARM64 CRC32 instruction without a runtime check if
// __ARM_FEATURE_CRC32 is defined. GCC and Clang only define
// this if the proper compiler options are used.
# if defined(__ARM_FEATURE_CRC32)
# define CRC32_ARCH_OPTIMIZED 1
# define CRC32_ARM64 1
# elif defined(CRC_ARM64_RUNTIME_DETECTION)
# define CRC32_ARCH_OPTIMIZED 1
# define CRC32_ARM64 1
# define CRC32_GENERIC 1
# endif
#endif
// LoongArch
//
// Only 64-bit LoongArch is supported for now. No runtime detection
// is needed because the LoongArch specification says that the CRC32
// instructions are a part of the Basic Integer Instructions and
// they shall be implemented by 64-bit LoongArch implementations.
#ifdef HAVE_LOONGARCH_CRC32
# define CRC32_ARCH_OPTIMIZED 1
# define CRC32_LOONGARCH 1
#endif
// x86 and E2K
#if defined(HAVE_USABLE_CLMUL)
// If CLMUL is allowed unconditionally in the compiler options then
// the generic version and the tables can be omitted. Exceptions:
//
// - If 32-bit x86 assembly files are enabled then those are always
// built and runtime detection is used even if compiler flags
// were set to allow CLMUL unconditionally.
//
// - The unconditional use doesn't work with MSVC as I don't know
// how to detect the features here.
//
// Don't enable CLMUL at all on old MSVC that targets 32-bit x86.
// There seems to be a compiler bug that produces broken code
// in optimized (Release) builds. It results in crashing tests.
// It is known that VS 2019 16.11 (MSVC 19.29.30158) is broken
// and that VS 2022 17.13 (MSVC 19.43.34808) works.
# if defined(_MSC_FULL_VER) && _MSC_FULL_VER < 194334808 \
&& !defined(__INTEL_COMPILER) && !defined(__clang__) \
&& defined(_M_IX86)
// Old MSVC targeting 32-bit x86: Don't enable CLMUL at all.
# elif (defined(__SSSE3__) && defined(__SSE4_1__) \
&& defined(__PCLMUL__) \
&& !defined(HAVE_CRC_X86_ASM)) \
|| (defined(__e2k__) && __iset__ >= 6)
# define CRC32_ARCH_OPTIMIZED 1
# define CRC64_ARCH_OPTIMIZED 1
# define CRC_X86_CLMUL 1
# else
# define CRC32_GENERIC 1
# define CRC64_GENERIC 1
# define CRC32_ARCH_OPTIMIZED 1
# define CRC64_ARCH_OPTIMIZED 1
# define CRC_X86_CLMUL 1
# endif
#endif
// Fallback configuration
//
// For CRC32 use the generic slice-by-eight implementation if no optimized
// version is available.
#if !defined(CRC32_ARCH_OPTIMIZED) && !defined(CRC32_GENERIC)
# define CRC32_GENERIC 1
#endif
// For CRC64 use the generic slice-by-four implementation if no optimized
// version is available.
#if !defined(CRC64_ARCH_OPTIMIZED) && !defined(CRC64_GENERIC)
# define CRC64_GENERIC 1
#endif
#endif