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- 13 Apr, 2021 1 commit
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Marko Mäkelä authored
In commit d25f806d (MDEV-22749) the CRC-32C implementation of MariaDB was broken on some IA-32 and AMD64 builds, depending on the compiler version and build options. This was verified for IA-32 on GCC 10.2.1. Even though we try to identify the SSE4.2 extensions and the availaibility of the PCLMULQDQ instruction by executing CPUID, the fall-back code could be generated with extended instructions, because the entire file mysys/crc32/crc32c.c was being compiled with -msse4.2 -mpclmul. This would cause SIGILL on a PINSRD instruction on affected IA-32 targets (such as some Intel Atom processors). This might also affect old AMD64 processors (predating the 2007 Intel Nehalem microarchitecture), if some compiler chose to emit the offending instructions. While it is fine to pass a target-specific option to a target-specific compilation unit (like -mpclmul to a PCLMUL-specific compilation unit), that is not safe for mixed-architecture compilation units. For mixed-architecture compilation units, the correct way is to set target attributes on the target-specific functions. There does not seem to be a way to pass target attributes to function template instantiation. Hence, we must replace the ExtendImpl template with plain functions crc32_sse42() and crc32_slow(). We will also remove some inconsistency between my_crc32_implementation() and mysys_namespace::crc32::Choose_Extend(). The function crc32_pclmul_enabled() will be moved to mysys/crc32/crc32c.cc so that the detection code will be compiled without -msse4.2 -mpclmul. The AMD64 PCLMUL accelerated crc32c_3way() will be moved to a new file crc32c_amd64.cc. In this way, only a few functions that depend on -msse4.2 in mysys/crc32/crc32c.cc can be declared with __attribute__((target("sse4.2"))), and most of the file can be compiled for the generic target. Last, the file mysys/crc32ieee.cc will be omitted on 64-bit POWER, because it was dead code (no symbols were exported). Reviewed by: Vladislav Vaintroub
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- 07 Sep, 2020 1 commit
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Vladislav Vaintroub authored
Fix DBUG_ASSERT
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- 04 Sep, 2020 1 commit
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Vladislav Vaintroub authored
Removed some inine assembly, replaced by code from https://github.com/intel/soft-crc Also,replace GCC inline assembly for cpuid in ut0crc32 with __cpuid, to fix "PIC register clobbered by 'ebx' in 'asm'. This enables fast CRC32C on 32bit Intel processors with GCC.
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- 27 Aug, 2020 1 commit
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Marko Mäkelä authored
MDEV-22641 in commit dec3f8ca refactored a SIMD implementation of CRC-32 for the ISO 3309 polynomial that uses the IA-32/AMD64 carry-less multiplication (pclmul) instructions. The code was previously only available in Mariabackup; it was changed to be a general replacement of the zlib crc32(). There exist AMD64 systems where CMAKE_SYSTEM_PROCESSOR matches the pattern i[36]86 but not x86_64 or amd64. This would cause a link failure, because mysys/checksum.c would basically assume that the compiler support for instruction is always available on GCC-compatible compilers on AMD64. Furthermore, we were unnecessarily disabling the SIMD acceleration for 32-bit executables. Note: Until MDEV-22749 has been implemented, the PCLMUL instruction will not be used on Microsoft Windows. Closes: #1660
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- 01 Jun, 2020 1 commit
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mysqlonarm authored
Existing implementation used my_checksum (from mysys) for calculating table checksum and binlog checksum. This implementation was optimized for powerpc only and lacked SIMD implementation for x86 (using clmul) and ARM (using ACLE) instead used zlib-crc32. mariabackup had its own copy of the crc32 implementation using hardware optimized implementation only for x86 and lagged hardware based implementation for powerpc and ARM. Patch helps unifies all such calls and help aggregate all of them using an unified interface my_checksum(). Said unification also enables hardware optimized calls for all architecture viz. x86, ARM, POWERPC. Default always fallback to zlib crc32. Thanks to Daniel Black for reviewing, fixing and testing PowerPC changes. Thanks to Marko and Daniel for early code feedback.
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- 12 Mar, 2020 1 commit
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Marko Mäkelä authored
The -Wconversion in GCC seems to be stricter than in clang. GCC at least since version 4.4.7 issues truncation warnings for assignments to bitfields, while clang 10 appears to only issue warnings when the sizes in bytes rounded to the nearest integer powers of 2 are different. Before GCC 10.0.0, -Wconversion required more casts and would not allow some operations, such as x<<=1 or x+=1 on a data type that is narrower than int. GCC 5 (but not GCC 4, GCC 6, or any later version) is complaining about x|=y even when x and y are compatible types that are narrower than int. Hence, we must rewrite some x|=y as x=static_cast<byte>(x|y) or similar, or we must disable -Wconversion. In GCC 6 and later, the warning for assigning wider to bitfields that are narrower than 8, 16, or 32 bits can be suppressed by applying a bitwise & with the exact bitmask of the bitfield. For older GCC, we must disable -Wconversion for GCC 4 or 5 in such cases. The bitwise negation operator appears to promote short integers to a wider type, and hence we must add explicit truncation casts around them. Microsoft Visual C does not allow a static_cast to truncate a constant, such as static_cast<byte>(1) truncating int. Hence, we will use the constructor-style cast byte(~1) for such cases. This has been tested at least with GCC 4.8.5, 5.4.0, 7.4.0, 9.2.1, 10.0.0, clang 9.0.1, 10.0.0, and MSVC 14.22.27905 (Microsoft Visual Studio 2019) on 64-bit and 32-bit targets (IA-32, AMD64, POWER 8, POWER 9, ARMv8).
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- 11 May, 2019 1 commit
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Vicențiu Ciorbaru authored
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- 30 Oct, 2018 1 commit
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Daniel Black authored
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- 26 Apr, 2018 1 commit
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Monty authored
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- 27 Apr, 2017 1 commit
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Vladislav Vaintroub authored
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