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459969e993
Summary: **Background** - runtime detection of certain x86 CPU features was added for optimizing CRC32c checksums, where performance is dramatically affected by the availability of certain CPU instructions and code using intrinsics for those instructions. And Java builds with native library try to be broadly compatible but performant. What has changed is that CRC32c is no longer the most efficient cheecksum on contemporary x86_64 hardware, nor the default checksum. XXH3 is generally faster and not as dramatically impacted by the availability of certain CPU instructions. For example, on my Skylake system using db_bench (similar on an older Skylake system without AVX512): PORTABLE=1 empty USE_SSE : xxh3->8 GB/s crc32c->0.8 GB/s (no SSE4.2 nor AVX2 instructions) PORTABLE=1 USE_SSE=1 : xxh3->19 GB/s crc32c->16 GB/s (with SSE4.2 and AVX2) PORTABLE=0 USE_SSE ignored: xxh3->28 GB/s crc32c->16 GB/s (also some AVX512) Testing a ~10 year old system, with SSE4.2 but without AVX2, crc32c is a similar speed to the new systems but xxh3 is only about half that speed, also 8GB/s like the non-AVX2 compile above. Given that xxh3 has specific optimization for AVX2, I think we can infer that that crc32c is only fastest for that ~2008-2013 period when SSE4.2 was included but not AVX2. And given that xxh3 is only about 2x slower on these systems (not like >10x slower for unoptimized crc32c), I don't think we need to invest too much in optimally adapting to these old cases. x86 hardware that doesn't support fast CRC32c is now extremely rare, so requiring a custom build to support such hardware is fine IMHO. **This change** does two related things: * Remove runtime CPU detection for optimizing CRC32c on x86. Maintaining this code is non-zero work, and compiling special code that doesn't work on the configured target instruction set for code generation is always dubious. (On the one hand we have to ensure the CRC32c code uses SSE4.2 but on the other hand we have to ensure nothing else does.) * Detect CPU features in source code, not in build scripts. Although there are some hypothetical advantages to detectiong in build scripts (compiler generality), RocksDB supports at least three build systems: make, cmake, and buck. It's not practical to support feature detection on all three, and we have suffered from missed optimization opportunities by relying on missing or incomplete detection in cmake and buck. We also depend on some components like xxhash that do source code detection anyway. **In more detail:** * `HAVE_SSE42`, `HAVE_AVX2`, and `HAVE_PCLMUL` replaced by standard macros `__SSE4_2__`, `__AVX2__`, and `__PCLMUL__`. * MSVC does not provide high fidelity defines for SSE, PCLMUL, or POPCNT, but we can infer those from `__AVX__` or `__AVX2__` in a compatibility header. In rare cases of false negative or false positive feature detection, a build engineer should be able to set defines to work around the issue. * `__POPCNT__` is another standard define, but we happen to only need it on MSVC, where it is set by that compatibility header, or can be set by the build engineer. * `PORTABLE` can be set to a CPU type, e.g. "haswell", to compile for that CPU type. * `USE_SSE` is deprecated, now equivalent to PORTABLE=haswell, which roughly approximates its old behavior. Notably, this change should enable more builds to use the AVX2-optimized Bloom filter implementation. Pull Request resolved: https://github.com/facebook/rocksdb/pull/11419 Test Plan: existing tests, CI Manual performance tests after the change match the before above (none expected with make build). We also see AVX2 optimized Bloom filter code enabled when expected, by injecting a compiler error. (Performance difference is not big on my current CPU.) Reviewed By: ajkr Differential Revision: D45489041 Pulled By: pdillinger fbshipit-source-id: 60ceb0dd2aa3b365c99ed08a8b2a087a9abb6a70
1293 lines
49 KiB
C++
1293 lines
49 KiB
C++
// Copyright (c) 2011-present, Facebook, Inc. All rights reserved.
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// This source code is licensed under both the GPLv2 (found in the
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// COPYING file in the root directory) and Apache 2.0 License
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// (found in the LICENSE.Apache file in the root directory).
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//
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// Copyright (c) 2011 The LevelDB Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style license that can be
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// found in the LICENSE file. See the AUTHORS file for names of contributors.
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//
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// A portable implementation of crc32c, optimized to handle
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// four bytes at a time.
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#include "util/crc32c.h"
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#include <stdint.h>
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#include <array>
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#include <utility>
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#include "port/lang.h"
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#include "util/coding.h"
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#include "util/crc32c_arm64.h"
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#include "util/math.h"
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#ifdef __powerpc64__
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#include "util/crc32c_ppc.h"
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#include "util/crc32c_ppc_constants.h"
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#if __linux__
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#ifdef ROCKSDB_AUXV_GETAUXVAL_PRESENT
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#include <sys/auxv.h>
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#endif
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#ifndef PPC_FEATURE2_VEC_CRYPTO
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#define PPC_FEATURE2_VEC_CRYPTO 0x02000000
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#endif
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#ifndef AT_HWCAP2
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#define AT_HWCAP2 26
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#endif
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#elif __FreeBSD__
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#include <machine/cpu.h>
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#include <sys/auxv.h>
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#include <sys/elf_common.h>
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#endif /* __linux__ */
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#endif
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ASSERT_FEATURE_COMPAT_HEADER();
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#ifdef __SSE4_2__
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#include <nmmintrin.h>
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#include <wmmintrin.h>
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#endif
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#if defined(HAVE_ARM64_CRC)
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bool pmull_runtime_flag = false;
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#endif
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namespace ROCKSDB_NAMESPACE {
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namespace crc32c {
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#if defined(HAVE_POWER8) && defined(HAS_ALTIVEC)
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#ifdef __powerpc64__
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static int arch_ppc_crc32 = 0;
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#endif /* __powerpc64__ */
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#endif
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static const uint32_t table0_[256] = {
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0x00000000, 0xf26b8303, 0xe13b70f7, 0x1350f3f4, 0xc79a971f, 0x35f1141c,
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0x26a1e7e8, 0xd4ca64eb, 0x8ad958cf, 0x78b2dbcc, 0x6be22838, 0x9989ab3b,
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0x4d43cfd0, 0xbf284cd3, 0xac78bf27, 0x5e133c24, 0x105ec76f, 0xe235446c,
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0xf165b798, 0x030e349b, 0xd7c45070, 0x25afd373, 0x36ff2087, 0xc494a384,
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0x9a879fa0, 0x68ec1ca3, 0x7bbcef57, 0x89d76c54, 0x5d1d08bf, 0xaf768bbc,
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0xbc267848, 0x4e4dfb4b, 0x20bd8ede, 0xd2d60ddd, 0xc186fe29, 0x33ed7d2a,
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0xe72719c1, 0x154c9ac2, 0x061c6936, 0xf477ea35, 0xaa64d611, 0x580f5512,
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0x4b5fa6e6, 0xb93425e5, 0x6dfe410e, 0x9f95c20d, 0x8cc531f9, 0x7eaeb2fa,
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0x30e349b1, 0xc288cab2, 0xd1d83946, 0x23b3ba45, 0xf779deae, 0x05125dad,
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0x1642ae59, 0xe4292d5a, 0xba3a117e, 0x4851927d, 0x5b016189, 0xa96ae28a,
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0x7da08661, 0x8fcb0562, 0x9c9bf696, 0x6ef07595, 0x417b1dbc, 0xb3109ebf,
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0xa0406d4b, 0x522bee48, 0x86e18aa3, 0x748a09a0, 0x67dafa54, 0x95b17957,
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0xcba24573, 0x39c9c670, 0x2a993584, 0xd8f2b687, 0x0c38d26c, 0xfe53516f,
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0xed03a29b, 0x1f682198, 0x5125dad3, 0xa34e59d0, 0xb01eaa24, 0x42752927,
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0x96bf4dcc, 0x64d4cecf, 0x77843d3b, 0x85efbe38, 0xdbfc821c, 0x2997011f,
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0x3ac7f2eb, 0xc8ac71e8, 0x1c661503, 0xee0d9600, 0xfd5d65f4, 0x0f36e6f7,
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0x61c69362, 0x93ad1061, 0x80fde395, 0x72966096, 0xa65c047d, 0x5437877e,
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0x4767748a, 0xb50cf789, 0xeb1fcbad, 0x197448ae, 0x0a24bb5a, 0xf84f3859,
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0x2c855cb2, 0xdeeedfb1, 0xcdbe2c45, 0x3fd5af46, 0x7198540d, 0x83f3d70e,
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0x90a324fa, 0x62c8a7f9, 0xb602c312, 0x44694011, 0x5739b3e5, 0xa55230e6,
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0xfb410cc2, 0x092a8fc1, 0x1a7a7c35, 0xe811ff36, 0x3cdb9bdd, 0xceb018de,
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0xdde0eb2a, 0x2f8b6829, 0x82f63b78, 0x709db87b, 0x63cd4b8f, 0x91a6c88c,
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0x456cac67, 0xb7072f64, 0xa457dc90, 0x563c5f93, 0x082f63b7, 0xfa44e0b4,
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0xe9141340, 0x1b7f9043, 0xcfb5f4a8, 0x3dde77ab, 0x2e8e845f, 0xdce5075c,
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0x92a8fc17, 0x60c37f14, 0x73938ce0, 0x81f80fe3, 0x55326b08, 0xa759e80b,
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0xb4091bff, 0x466298fc, 0x1871a4d8, 0xea1a27db, 0xf94ad42f, 0x0b21572c,
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0xdfeb33c7, 0x2d80b0c4, 0x3ed04330, 0xccbbc033, 0xa24bb5a6, 0x502036a5,
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0x4370c551, 0xb11b4652, 0x65d122b9, 0x97baa1ba, 0x84ea524e, 0x7681d14d,
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0x2892ed69, 0xdaf96e6a, 0xc9a99d9e, 0x3bc21e9d, 0xef087a76, 0x1d63f975,
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0x0e330a81, 0xfc588982, 0xb21572c9, 0x407ef1ca, 0x532e023e, 0xa145813d,
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0x758fe5d6, 0x87e466d5, 0x94b49521, 0x66df1622, 0x38cc2a06, 0xcaa7a905,
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0xd9f75af1, 0x2b9cd9f2, 0xff56bd19, 0x0d3d3e1a, 0x1e6dcdee, 0xec064eed,
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0xc38d26c4, 0x31e6a5c7, 0x22b65633, 0xd0ddd530, 0x0417b1db, 0xf67c32d8,
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0xe52cc12c, 0x1747422f, 0x49547e0b, 0xbb3ffd08, 0xa86f0efc, 0x5a048dff,
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0x8ecee914, 0x7ca56a17, 0x6ff599e3, 0x9d9e1ae0, 0xd3d3e1ab, 0x21b862a8,
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0x32e8915c, 0xc083125f, 0x144976b4, 0xe622f5b7, 0xf5720643, 0x07198540,
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0x590ab964, 0xab613a67, 0xb831c993, 0x4a5a4a90, 0x9e902e7b, 0x6cfbad78,
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0x7fab5e8c, 0x8dc0dd8f, 0xe330a81a, 0x115b2b19, 0x020bd8ed, 0xf0605bee,
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0x24aa3f05, 0xd6c1bc06, 0xc5914ff2, 0x37faccf1, 0x69e9f0d5, 0x9b8273d6,
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0x88d28022, 0x7ab90321, 0xae7367ca, 0x5c18e4c9, 0x4f48173d, 0xbd23943e,
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0xf36e6f75, 0x0105ec76, 0x12551f82, 0xe03e9c81, 0x34f4f86a, 0xc69f7b69,
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0xd5cf889d, 0x27a40b9e, 0x79b737ba, 0x8bdcb4b9, 0x988c474d, 0x6ae7c44e,
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0xbe2da0a5, 0x4c4623a6, 0x5f16d052, 0xad7d5351};
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#ifndef __SSE4_2__
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static const uint32_t table1_[256] = {
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0x00000000, 0x13a29877, 0x274530ee, 0x34e7a899, 0x4e8a61dc, 0x5d28f9ab,
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0x69cf5132, 0x7a6dc945, 0x9d14c3b8, 0x8eb65bcf, 0xba51f356, 0xa9f36b21,
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0xd39ea264, 0xc03c3a13, 0xf4db928a, 0xe7790afd, 0x3fc5f181, 0x2c6769f6,
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0x1880c16f, 0x0b225918, 0x714f905d, 0x62ed082a, 0x560aa0b3, 0x45a838c4,
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0xa2d13239, 0xb173aa4e, 0x859402d7, 0x96369aa0, 0xec5b53e5, 0xfff9cb92,
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0xcb1e630b, 0xd8bcfb7c, 0x7f8be302, 0x6c297b75, 0x58ced3ec, 0x4b6c4b9b,
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0x310182de, 0x22a31aa9, 0x1644b230, 0x05e62a47, 0xe29f20ba, 0xf13db8cd,
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0xc5da1054, 0xd6788823, 0xac154166, 0xbfb7d911, 0x8b507188, 0x98f2e9ff,
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0x404e1283, 0x53ec8af4, 0x670b226d, 0x74a9ba1a, 0x0ec4735f, 0x1d66eb28,
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0x298143b1, 0x3a23dbc6, 0xdd5ad13b, 0xcef8494c, 0xfa1fe1d5, 0xe9bd79a2,
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0x93d0b0e7, 0x80722890, 0xb4958009, 0xa737187e, 0xff17c604, 0xecb55e73,
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0xd852f6ea, 0xcbf06e9d, 0xb19da7d8, 0xa23f3faf, 0x96d89736, 0x857a0f41,
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0x620305bc, 0x71a19dcb, 0x45463552, 0x56e4ad25, 0x2c896460, 0x3f2bfc17,
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0x0bcc548e, 0x186eccf9, 0xc0d23785, 0xd370aff2, 0xe797076b, 0xf4359f1c,
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0x8e585659, 0x9dface2e, 0xa91d66b7, 0xbabffec0, 0x5dc6f43d, 0x4e646c4a,
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0x7a83c4d3, 0x69215ca4, 0x134c95e1, 0x00ee0d96, 0x3409a50f, 0x27ab3d78,
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0x809c2506, 0x933ebd71, 0xa7d915e8, 0xb47b8d9f, 0xce1644da, 0xddb4dcad,
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0xe9537434, 0xfaf1ec43, 0x1d88e6be, 0x0e2a7ec9, 0x3acdd650, 0x296f4e27,
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0x53028762, 0x40a01f15, 0x7447b78c, 0x67e52ffb, 0xbf59d487, 0xacfb4cf0,
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0x981ce469, 0x8bbe7c1e, 0xf1d3b55b, 0xe2712d2c, 0xd69685b5, 0xc5341dc2,
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0x224d173f, 0x31ef8f48, 0x050827d1, 0x16aabfa6, 0x6cc776e3, 0x7f65ee94,
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0x4b82460d, 0x5820de7a, 0xfbc3faf9, 0xe861628e, 0xdc86ca17, 0xcf245260,
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0xb5499b25, 0xa6eb0352, 0x920cabcb, 0x81ae33bc, 0x66d73941, 0x7575a136,
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0x419209af, 0x523091d8, 0x285d589d, 0x3bffc0ea, 0x0f186873, 0x1cbaf004,
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0xc4060b78, 0xd7a4930f, 0xe3433b96, 0xf0e1a3e1, 0x8a8c6aa4, 0x992ef2d3,
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0xadc95a4a, 0xbe6bc23d, 0x5912c8c0, 0x4ab050b7, 0x7e57f82e, 0x6df56059,
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0x1798a91c, 0x043a316b, 0x30dd99f2, 0x237f0185, 0x844819fb, 0x97ea818c,
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0xa30d2915, 0xb0afb162, 0xcac27827, 0xd960e050, 0xed8748c9, 0xfe25d0be,
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0x195cda43, 0x0afe4234, 0x3e19eaad, 0x2dbb72da, 0x57d6bb9f, 0x447423e8,
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0x70938b71, 0x63311306, 0xbb8de87a, 0xa82f700d, 0x9cc8d894, 0x8f6a40e3,
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0xf50789a6, 0xe6a511d1, 0xd242b948, 0xc1e0213f, 0x26992bc2, 0x353bb3b5,
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0x01dc1b2c, 0x127e835b, 0x68134a1e, 0x7bb1d269, 0x4f567af0, 0x5cf4e287,
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0x04d43cfd, 0x1776a48a, 0x23910c13, 0x30339464, 0x4a5e5d21, 0x59fcc556,
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0x6d1b6dcf, 0x7eb9f5b8, 0x99c0ff45, 0x8a626732, 0xbe85cfab, 0xad2757dc,
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0xd74a9e99, 0xc4e806ee, 0xf00fae77, 0xe3ad3600, 0x3b11cd7c, 0x28b3550b,
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0x1c54fd92, 0x0ff665e5, 0x759baca0, 0x663934d7, 0x52de9c4e, 0x417c0439,
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0xa6050ec4, 0xb5a796b3, 0x81403e2a, 0x92e2a65d, 0xe88f6f18, 0xfb2df76f,
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0xcfca5ff6, 0xdc68c781, 0x7b5fdfff, 0x68fd4788, 0x5c1aef11, 0x4fb87766,
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0x35d5be23, 0x26772654, 0x12908ecd, 0x013216ba, 0xe64b1c47, 0xf5e98430,
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0xc10e2ca9, 0xd2acb4de, 0xa8c17d9b, 0xbb63e5ec, 0x8f844d75, 0x9c26d502,
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0x449a2e7e, 0x5738b609, 0x63df1e90, 0x707d86e7, 0x0a104fa2, 0x19b2d7d5,
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0x2d557f4c, 0x3ef7e73b, 0xd98eedc6, 0xca2c75b1, 0xfecbdd28, 0xed69455f,
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0x97048c1a, 0x84a6146d, 0xb041bcf4, 0xa3e32483};
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static const uint32_t table2_[256] = {
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0x00000000, 0xa541927e, 0x4f6f520d, 0xea2ec073, 0x9edea41a, 0x3b9f3664,
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0xd1b1f617, 0x74f06469, 0x38513ec5, 0x9d10acbb, 0x773e6cc8, 0xd27ffeb6,
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0xa68f9adf, 0x03ce08a1, 0xe9e0c8d2, 0x4ca15aac, 0x70a27d8a, 0xd5e3eff4,
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0x3fcd2f87, 0x9a8cbdf9, 0xee7cd990, 0x4b3d4bee, 0xa1138b9d, 0x045219e3,
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0x48f3434f, 0xedb2d131, 0x079c1142, 0xa2dd833c, 0xd62de755, 0x736c752b,
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0x9942b558, 0x3c032726, 0xe144fb14, 0x4405696a, 0xae2ba919, 0x0b6a3b67,
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0x7f9a5f0e, 0xdadbcd70, 0x30f50d03, 0x95b49f7d, 0xd915c5d1, 0x7c5457af,
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0x967a97dc, 0x333b05a2, 0x47cb61cb, 0xe28af3b5, 0x08a433c6, 0xade5a1b8,
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0x91e6869e, 0x34a714e0, 0xde89d493, 0x7bc846ed, 0x0f382284, 0xaa79b0fa,
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0x40577089, 0xe516e2f7, 0xa9b7b85b, 0x0cf62a25, 0xe6d8ea56, 0x43997828,
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0x37691c41, 0x92288e3f, 0x78064e4c, 0xdd47dc32, 0xc76580d9, 0x622412a7,
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0x880ad2d4, 0x2d4b40aa, 0x59bb24c3, 0xfcfab6bd, 0x16d476ce, 0xb395e4b0,
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0xff34be1c, 0x5a752c62, 0xb05bec11, 0x151a7e6f, 0x61ea1a06, 0xc4ab8878,
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0x2e85480b, 0x8bc4da75, 0xb7c7fd53, 0x12866f2d, 0xf8a8af5e, 0x5de93d20,
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0x29195949, 0x8c58cb37, 0x66760b44, 0xc337993a, 0x8f96c396, 0x2ad751e8,
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0xc0f9919b, 0x65b803e5, 0x1148678c, 0xb409f5f2, 0x5e273581, 0xfb66a7ff,
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0x26217bcd, 0x8360e9b3, 0x694e29c0, 0xcc0fbbbe, 0xb8ffdfd7, 0x1dbe4da9,
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0xf7908dda, 0x52d11fa4, 0x1e704508, 0xbb31d776, 0x511f1705, 0xf45e857b,
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0x80aee112, 0x25ef736c, 0xcfc1b31f, 0x6a802161, 0x56830647, 0xf3c29439,
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0x19ec544a, 0xbcadc634, 0xc85da25d, 0x6d1c3023, 0x8732f050, 0x2273622e,
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0x6ed23882, 0xcb93aafc, 0x21bd6a8f, 0x84fcf8f1, 0xf00c9c98, 0x554d0ee6,
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0xbf63ce95, 0x1a225ceb, 0x8b277743, 0x2e66e53d, 0xc448254e, 0x6109b730,
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0x15f9d359, 0xb0b84127, 0x5a968154, 0xffd7132a, 0xb3764986, 0x1637dbf8,
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0xfc191b8b, 0x595889f5, 0x2da8ed9c, 0x88e97fe2, 0x62c7bf91, 0xc7862def,
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0xfb850ac9, 0x5ec498b7, 0xb4ea58c4, 0x11abcaba, 0x655baed3, 0xc01a3cad,
|
|
0x2a34fcde, 0x8f756ea0, 0xc3d4340c, 0x6695a672, 0x8cbb6601, 0x29faf47f,
|
|
0x5d0a9016, 0xf84b0268, 0x1265c21b, 0xb7245065, 0x6a638c57, 0xcf221e29,
|
|
0x250cde5a, 0x804d4c24, 0xf4bd284d, 0x51fcba33, 0xbbd27a40, 0x1e93e83e,
|
|
0x5232b292, 0xf77320ec, 0x1d5de09f, 0xb81c72e1, 0xccec1688, 0x69ad84f6,
|
|
0x83834485, 0x26c2d6fb, 0x1ac1f1dd, 0xbf8063a3, 0x55aea3d0, 0xf0ef31ae,
|
|
0x841f55c7, 0x215ec7b9, 0xcb7007ca, 0x6e3195b4, 0x2290cf18, 0x87d15d66,
|
|
0x6dff9d15, 0xc8be0f6b, 0xbc4e6b02, 0x190ff97c, 0xf321390f, 0x5660ab71,
|
|
0x4c42f79a, 0xe90365e4, 0x032da597, 0xa66c37e9, 0xd29c5380, 0x77ddc1fe,
|
|
0x9df3018d, 0x38b293f3, 0x7413c95f, 0xd1525b21, 0x3b7c9b52, 0x9e3d092c,
|
|
0xeacd6d45, 0x4f8cff3b, 0xa5a23f48, 0x00e3ad36, 0x3ce08a10, 0x99a1186e,
|
|
0x738fd81d, 0xd6ce4a63, 0xa23e2e0a, 0x077fbc74, 0xed517c07, 0x4810ee79,
|
|
0x04b1b4d5, 0xa1f026ab, 0x4bdee6d8, 0xee9f74a6, 0x9a6f10cf, 0x3f2e82b1,
|
|
0xd50042c2, 0x7041d0bc, 0xad060c8e, 0x08479ef0, 0xe2695e83, 0x4728ccfd,
|
|
0x33d8a894, 0x96993aea, 0x7cb7fa99, 0xd9f668e7, 0x9557324b, 0x3016a035,
|
|
0xda386046, 0x7f79f238, 0x0b899651, 0xaec8042f, 0x44e6c45c, 0xe1a75622,
|
|
0xdda47104, 0x78e5e37a, 0x92cb2309, 0x378ab177, 0x437ad51e, 0xe63b4760,
|
|
0x0c158713, 0xa954156d, 0xe5f54fc1, 0x40b4ddbf, 0xaa9a1dcc, 0x0fdb8fb2,
|
|
0x7b2bebdb, 0xde6a79a5, 0x3444b9d6, 0x91052ba8};
|
|
static const uint32_t table3_[256] = {
|
|
0x00000000, 0xdd45aab8, 0xbf672381, 0x62228939, 0x7b2231f3, 0xa6679b4b,
|
|
0xc4451272, 0x1900b8ca, 0xf64463e6, 0x2b01c95e, 0x49234067, 0x9466eadf,
|
|
0x8d665215, 0x5023f8ad, 0x32017194, 0xef44db2c, 0xe964b13d, 0x34211b85,
|
|
0x560392bc, 0x8b463804, 0x924680ce, 0x4f032a76, 0x2d21a34f, 0xf06409f7,
|
|
0x1f20d2db, 0xc2657863, 0xa047f15a, 0x7d025be2, 0x6402e328, 0xb9474990,
|
|
0xdb65c0a9, 0x06206a11, 0xd725148b, 0x0a60be33, 0x6842370a, 0xb5079db2,
|
|
0xac072578, 0x71428fc0, 0x136006f9, 0xce25ac41, 0x2161776d, 0xfc24ddd5,
|
|
0x9e0654ec, 0x4343fe54, 0x5a43469e, 0x8706ec26, 0xe524651f, 0x3861cfa7,
|
|
0x3e41a5b6, 0xe3040f0e, 0x81268637, 0x5c632c8f, 0x45639445, 0x98263efd,
|
|
0xfa04b7c4, 0x27411d7c, 0xc805c650, 0x15406ce8, 0x7762e5d1, 0xaa274f69,
|
|
0xb327f7a3, 0x6e625d1b, 0x0c40d422, 0xd1057e9a, 0xaba65fe7, 0x76e3f55f,
|
|
0x14c17c66, 0xc984d6de, 0xd0846e14, 0x0dc1c4ac, 0x6fe34d95, 0xb2a6e72d,
|
|
0x5de23c01, 0x80a796b9, 0xe2851f80, 0x3fc0b538, 0x26c00df2, 0xfb85a74a,
|
|
0x99a72e73, 0x44e284cb, 0x42c2eeda, 0x9f874462, 0xfda5cd5b, 0x20e067e3,
|
|
0x39e0df29, 0xe4a57591, 0x8687fca8, 0x5bc25610, 0xb4868d3c, 0x69c32784,
|
|
0x0be1aebd, 0xd6a40405, 0xcfa4bccf, 0x12e11677, 0x70c39f4e, 0xad8635f6,
|
|
0x7c834b6c, 0xa1c6e1d4, 0xc3e468ed, 0x1ea1c255, 0x07a17a9f, 0xdae4d027,
|
|
0xb8c6591e, 0x6583f3a6, 0x8ac7288a, 0x57828232, 0x35a00b0b, 0xe8e5a1b3,
|
|
0xf1e51979, 0x2ca0b3c1, 0x4e823af8, 0x93c79040, 0x95e7fa51, 0x48a250e9,
|
|
0x2a80d9d0, 0xf7c57368, 0xeec5cba2, 0x3380611a, 0x51a2e823, 0x8ce7429b,
|
|
0x63a399b7, 0xbee6330f, 0xdcc4ba36, 0x0181108e, 0x1881a844, 0xc5c402fc,
|
|
0xa7e68bc5, 0x7aa3217d, 0x52a0c93f, 0x8fe56387, 0xedc7eabe, 0x30824006,
|
|
0x2982f8cc, 0xf4c75274, 0x96e5db4d, 0x4ba071f5, 0xa4e4aad9, 0x79a10061,
|
|
0x1b838958, 0xc6c623e0, 0xdfc69b2a, 0x02833192, 0x60a1b8ab, 0xbde41213,
|
|
0xbbc47802, 0x6681d2ba, 0x04a35b83, 0xd9e6f13b, 0xc0e649f1, 0x1da3e349,
|
|
0x7f816a70, 0xa2c4c0c8, 0x4d801be4, 0x90c5b15c, 0xf2e73865, 0x2fa292dd,
|
|
0x36a22a17, 0xebe780af, 0x89c50996, 0x5480a32e, 0x8585ddb4, 0x58c0770c,
|
|
0x3ae2fe35, 0xe7a7548d, 0xfea7ec47, 0x23e246ff, 0x41c0cfc6, 0x9c85657e,
|
|
0x73c1be52, 0xae8414ea, 0xcca69dd3, 0x11e3376b, 0x08e38fa1, 0xd5a62519,
|
|
0xb784ac20, 0x6ac10698, 0x6ce16c89, 0xb1a4c631, 0xd3864f08, 0x0ec3e5b0,
|
|
0x17c35d7a, 0xca86f7c2, 0xa8a47efb, 0x75e1d443, 0x9aa50f6f, 0x47e0a5d7,
|
|
0x25c22cee, 0xf8878656, 0xe1873e9c, 0x3cc29424, 0x5ee01d1d, 0x83a5b7a5,
|
|
0xf90696d8, 0x24433c60, 0x4661b559, 0x9b241fe1, 0x8224a72b, 0x5f610d93,
|
|
0x3d4384aa, 0xe0062e12, 0x0f42f53e, 0xd2075f86, 0xb025d6bf, 0x6d607c07,
|
|
0x7460c4cd, 0xa9256e75, 0xcb07e74c, 0x16424df4, 0x106227e5, 0xcd278d5d,
|
|
0xaf050464, 0x7240aedc, 0x6b401616, 0xb605bcae, 0xd4273597, 0x09629f2f,
|
|
0xe6264403, 0x3b63eebb, 0x59416782, 0x8404cd3a, 0x9d0475f0, 0x4041df48,
|
|
0x22635671, 0xff26fcc9, 0x2e238253, 0xf36628eb, 0x9144a1d2, 0x4c010b6a,
|
|
0x5501b3a0, 0x88441918, 0xea669021, 0x37233a99, 0xd867e1b5, 0x05224b0d,
|
|
0x6700c234, 0xba45688c, 0xa345d046, 0x7e007afe, 0x1c22f3c7, 0xc167597f,
|
|
0xc747336e, 0x1a0299d6, 0x782010ef, 0xa565ba57, 0xbc65029d, 0x6120a825,
|
|
0x0302211c, 0xde478ba4, 0x31035088, 0xec46fa30, 0x8e647309, 0x5321d9b1,
|
|
0x4a21617b, 0x9764cbc3, 0xf54642fa, 0x2803e842};
|
|
|
|
// Used to fetch a naturally-aligned 32-bit word in little endian byte-order
|
|
static inline uint32_t LE_LOAD32(const uint8_t* p) {
|
|
return DecodeFixed32(reinterpret_cast<const char*>(p));
|
|
}
|
|
#endif // !__SSE4_2__
|
|
|
|
static inline void DefaultCRC32(uint64_t* l, uint8_t const** p) {
|
|
#ifndef __SSE4_2__
|
|
uint32_t c = static_cast<uint32_t>(*l ^ LE_LOAD32(*p));
|
|
*p += 4;
|
|
*l = table3_[c & 0xff] ^ table2_[(c >> 8) & 0xff] ^
|
|
table1_[(c >> 16) & 0xff] ^ table0_[c >> 24];
|
|
// DO it twice.
|
|
c = static_cast<uint32_t>(*l ^ LE_LOAD32(*p));
|
|
*p += 4;
|
|
*l = table3_[c & 0xff] ^ table2_[(c >> 8) & 0xff] ^
|
|
table1_[(c >> 16) & 0xff] ^ table0_[c >> 24];
|
|
#elif defined(__LP64__) || defined(_WIN64)
|
|
*l = _mm_crc32_u64(*l, DecodeFixed64(reinterpret_cast<const char*>(*p)));
|
|
*p += 8;
|
|
#else
|
|
*l = _mm_crc32_u32(static_cast<unsigned int>(*l), LE_LOAD32(*p));
|
|
*p += 4;
|
|
*l = _mm_crc32_u32(static_cast<unsigned int>(*l), LE_LOAD32(*p));
|
|
*p += 4;
|
|
#endif
|
|
}
|
|
|
|
template <void (*CRC32)(uint64_t*, uint8_t const**)>
|
|
uint32_t ExtendImpl(uint32_t crc, const char* buf, size_t size) {
|
|
const uint8_t* p = reinterpret_cast<const uint8_t*>(buf);
|
|
const uint8_t* e = p + size;
|
|
uint64_t l = crc ^ 0xffffffffu;
|
|
|
|
// Align n to (1 << m) byte boundary
|
|
#define ALIGN(n, m) ((n + ((1 << m) - 1)) & ~((1 << m) - 1))
|
|
|
|
#define STEP1 \
|
|
do { \
|
|
int c = (l & 0xff) ^ *p++; \
|
|
l = table0_[c] ^ (l >> 8); \
|
|
} while (0)
|
|
|
|
// Point x at first 16-byte aligned byte in string. This might be
|
|
// just past the end of the string.
|
|
const uintptr_t pval = reinterpret_cast<uintptr_t>(p);
|
|
const uint8_t* x = reinterpret_cast<const uint8_t*>(ALIGN(pval, 4));
|
|
if (x <= e) {
|
|
// Process bytes until finished or p is 16-byte aligned
|
|
while (p != x) {
|
|
STEP1;
|
|
}
|
|
}
|
|
// Process bytes 16 at a time
|
|
while ((e - p) >= 16) {
|
|
CRC32(&l, &p);
|
|
CRC32(&l, &p);
|
|
}
|
|
// Process bytes 8 at a time
|
|
while ((e - p) >= 8) {
|
|
CRC32(&l, &p);
|
|
}
|
|
// Process the last few bytes
|
|
while (p != e) {
|
|
STEP1;
|
|
}
|
|
#undef STEP1
|
|
#undef ALIGN
|
|
return static_cast<uint32_t>(l ^ 0xffffffffu);
|
|
}
|
|
|
|
using Function = uint32_t (*)(uint32_t, const char*, size_t);
|
|
|
|
#if defined(HAVE_POWER8) && defined(HAS_ALTIVEC)
|
|
uint32_t ExtendPPCImpl(uint32_t crc, const char* buf, size_t size) {
|
|
return crc32c_ppc(crc, (const unsigned char*)buf, size);
|
|
}
|
|
|
|
#if __linux__
|
|
static int arch_ppc_probe(void) {
|
|
arch_ppc_crc32 = 0;
|
|
|
|
#if defined(__powerpc64__) && defined(ROCKSDB_AUXV_GETAUXVAL_PRESENT)
|
|
if (getauxval(AT_HWCAP2) & PPC_FEATURE2_VEC_CRYPTO) arch_ppc_crc32 = 1;
|
|
#endif /* __powerpc64__ */
|
|
|
|
return arch_ppc_crc32;
|
|
}
|
|
#elif __FreeBSD__
|
|
static int arch_ppc_probe(void) {
|
|
unsigned long cpufeatures;
|
|
arch_ppc_crc32 = 0;
|
|
|
|
#if defined(__powerpc64__)
|
|
elf_aux_info(AT_HWCAP2, &cpufeatures, sizeof(cpufeatures));
|
|
if (cpufeatures & PPC_FEATURE2_HAS_VEC_CRYPTO) arch_ppc_crc32 = 1;
|
|
#endif /* __powerpc64__ */
|
|
|
|
return arch_ppc_crc32;
|
|
}
|
|
#endif // __linux__
|
|
|
|
static bool isAltiVec() {
|
|
if (arch_ppc_probe()) {
|
|
return true;
|
|
} else {
|
|
return false;
|
|
}
|
|
}
|
|
#endif
|
|
|
|
#if defined(HAVE_ARM64_CRC)
|
|
uint32_t ExtendARMImpl(uint32_t crc, const char* buf, size_t size) {
|
|
return crc32c_arm64(crc, (const unsigned char*)buf, size);
|
|
}
|
|
#endif
|
|
|
|
std::string IsFastCrc32Supported() {
|
|
bool has_fast_crc = false;
|
|
std::string fast_zero_msg;
|
|
std::string arch;
|
|
#ifdef HAVE_POWER8
|
|
#ifdef HAS_ALTIVEC
|
|
if (arch_ppc_probe()) {
|
|
has_fast_crc = true;
|
|
arch = "PPC";
|
|
}
|
|
#else
|
|
has_fast_crc = false;
|
|
arch = "PPC";
|
|
#endif
|
|
#elif defined(HAVE_ARM64_CRC)
|
|
if (crc32c_runtime_check()) {
|
|
has_fast_crc = true;
|
|
arch = "Arm64";
|
|
pmull_runtime_flag = crc32c_pmull_runtime_check();
|
|
} else {
|
|
has_fast_crc = false;
|
|
arch = "Arm64";
|
|
}
|
|
#else
|
|
#ifdef __SSE4_2__
|
|
has_fast_crc = true;
|
|
#endif // __SSE4_2__
|
|
arch = "x86";
|
|
#endif
|
|
if (has_fast_crc) {
|
|
fast_zero_msg.append("Supported on " + arch);
|
|
} else {
|
|
fast_zero_msg.append("Not supported on " + arch);
|
|
}
|
|
return fast_zero_msg;
|
|
}
|
|
|
|
/*
|
|
* Copyright 2016 Ferry Toth, Exalon Delft BV, The Netherlands
|
|
* This software is provided 'as-is', without any express or implied
|
|
* warranty. In no event will the author be held liable for any damages
|
|
* arising from the use of this software.
|
|
* Permission is granted to anyone to use this software for any purpose,
|
|
* including commercial applications, and to alter it and redistribute it
|
|
* freely, subject to the following restrictions:
|
|
* 1. The origin of this software must not be misrepresented; you must not
|
|
* claim that you wrote the original software. If you use this software
|
|
* in a product, an acknowledgment in the product documentation would be
|
|
* appreciated but is not required.
|
|
* 2. Altered source versions must be plainly marked as such, and must not be
|
|
* misrepresented as being the original software.
|
|
* 3. This notice may not be removed or altered from any source distribution.
|
|
* Ferry Toth
|
|
* ftoth@exalondelft.nl
|
|
*
|
|
* https://github.com/htot/crc32c
|
|
*
|
|
* Modified by Facebook
|
|
*
|
|
* Original intel whitepaper:
|
|
* "Fast CRC Computation for iSCSI Polynomial Using CRC32 Instruction"
|
|
* https://www.intel.com/content/dam/www/public/us/en/documents/white-papers/crc-iscsi-polynomial-crc32-instruction-paper.pdf
|
|
*
|
|
* This version is from the folly library, created by Dave Watson
|
|
* <davejwatson@fb.com>
|
|
*
|
|
*/
|
|
#if defined(__SSE4_2__) && defined(__PCLMUL__)
|
|
|
|
#define CRCtriplet(crc, buf, offset) \
|
|
crc##0 = _mm_crc32_u64(crc##0, *(buf##0 + offset)); \
|
|
crc##1 = _mm_crc32_u64(crc##1, *(buf##1 + offset)); \
|
|
crc##2 = _mm_crc32_u64(crc##2, *(buf##2 + offset));
|
|
|
|
#define CRCduplet(crc, buf, offset) \
|
|
crc##0 = _mm_crc32_u64(crc##0, *(buf##0 + offset)); \
|
|
crc##1 = _mm_crc32_u64(crc##1, *(buf##1 + offset));
|
|
|
|
#define CRCsinglet(crc, buf, offset) \
|
|
crc = _mm_crc32_u64(crc, *(uint64_t*)(buf + offset));
|
|
|
|
// Numbers taken directly from intel whitepaper.
|
|
// clang-format off
|
|
const uint64_t clmul_constants[] = {
|
|
0x14cd00bd6, 0x105ec76f0, 0x0ba4fc28e, 0x14cd00bd6,
|
|
0x1d82c63da, 0x0f20c0dfe, 0x09e4addf8, 0x0ba4fc28e,
|
|
0x039d3b296, 0x1384aa63a, 0x102f9b8a2, 0x1d82c63da,
|
|
0x14237f5e6, 0x01c291d04, 0x00d3b6092, 0x09e4addf8,
|
|
0x0c96cfdc0, 0x0740eef02, 0x18266e456, 0x039d3b296,
|
|
0x0daece73e, 0x0083a6eec, 0x0ab7aff2a, 0x102f9b8a2,
|
|
0x1248ea574, 0x1c1733996, 0x083348832, 0x14237f5e6,
|
|
0x12c743124, 0x02ad91c30, 0x0b9e02b86, 0x00d3b6092,
|
|
0x018b33a4e, 0x06992cea2, 0x1b331e26a, 0x0c96cfdc0,
|
|
0x17d35ba46, 0x07e908048, 0x1bf2e8b8a, 0x18266e456,
|
|
0x1a3e0968a, 0x11ed1f9d8, 0x0ce7f39f4, 0x0daece73e,
|
|
0x061d82e56, 0x0f1d0f55e, 0x0d270f1a2, 0x0ab7aff2a,
|
|
0x1c3f5f66c, 0x0a87ab8a8, 0x12ed0daac, 0x1248ea574,
|
|
0x065863b64, 0x08462d800, 0x11eef4f8e, 0x083348832,
|
|
0x1ee54f54c, 0x071d111a8, 0x0b3e32c28, 0x12c743124,
|
|
0x0064f7f26, 0x0ffd852c6, 0x0dd7e3b0c, 0x0b9e02b86,
|
|
0x0f285651c, 0x0dcb17aa4, 0x010746f3c, 0x018b33a4e,
|
|
0x1c24afea4, 0x0f37c5aee, 0x0271d9844, 0x1b331e26a,
|
|
0x08e766a0c, 0x06051d5a2, 0x093a5f730, 0x17d35ba46,
|
|
0x06cb08e5c, 0x11d5ca20e, 0x06b749fb2, 0x1bf2e8b8a,
|
|
0x1167f94f2, 0x021f3d99c, 0x0cec3662e, 0x1a3e0968a,
|
|
0x19329634a, 0x08f158014, 0x0e6fc4e6a, 0x0ce7f39f4,
|
|
0x08227bb8a, 0x1a5e82106, 0x0b0cd4768, 0x061d82e56,
|
|
0x13c2b89c4, 0x188815ab2, 0x0d7a4825c, 0x0d270f1a2,
|
|
0x10f5ff2ba, 0x105405f3e, 0x00167d312, 0x1c3f5f66c,
|
|
0x0f6076544, 0x0e9adf796, 0x026f6a60a, 0x12ed0daac,
|
|
0x1a2adb74e, 0x096638b34, 0x19d34af3a, 0x065863b64,
|
|
0x049c3cc9c, 0x1e50585a0, 0x068bce87a, 0x11eef4f8e,
|
|
0x1524fa6c6, 0x19f1c69dc, 0x16cba8aca, 0x1ee54f54c,
|
|
0x042d98888, 0x12913343e, 0x1329d9f7e, 0x0b3e32c28,
|
|
0x1b1c69528, 0x088f25a3a, 0x02178513a, 0x0064f7f26,
|
|
0x0e0ac139e, 0x04e36f0b0, 0x0170076fa, 0x0dd7e3b0c,
|
|
0x141a1a2e2, 0x0bd6f81f8, 0x16ad828b4, 0x0f285651c,
|
|
0x041d17b64, 0x19425cbba, 0x1fae1cc66, 0x010746f3c,
|
|
0x1a75b4b00, 0x18db37e8a, 0x0f872e54c, 0x1c24afea4,
|
|
0x01e41e9fc, 0x04c144932, 0x086d8e4d2, 0x0271d9844,
|
|
0x160f7af7a, 0x052148f02, 0x05bb8f1bc, 0x08e766a0c,
|
|
0x0a90fd27a, 0x0a3c6f37a, 0x0b3af077a, 0x093a5f730,
|
|
0x04984d782, 0x1d22c238e, 0x0ca6ef3ac, 0x06cb08e5c,
|
|
0x0234e0b26, 0x063ded06a, 0x1d88abd4a, 0x06b749fb2,
|
|
0x04597456a, 0x04d56973c, 0x0e9e28eb4, 0x1167f94f2,
|
|
0x07b3ff57a, 0x19385bf2e, 0x0c9c8b782, 0x0cec3662e,
|
|
0x13a9cba9e, 0x0e417f38a, 0x093e106a4, 0x19329634a,
|
|
0x167001a9c, 0x14e727980, 0x1ddffc5d4, 0x0e6fc4e6a,
|
|
0x00df04680, 0x0d104b8fc, 0x02342001e, 0x08227bb8a,
|
|
0x00a2a8d7e, 0x05b397730, 0x168763fa6, 0x0b0cd4768,
|
|
0x1ed5a407a, 0x0e78eb416, 0x0d2c3ed1a, 0x13c2b89c4,
|
|
0x0995a5724, 0x1641378f0, 0x19b1afbc4, 0x0d7a4825c,
|
|
0x109ffedc0, 0x08d96551c, 0x0f2271e60, 0x10f5ff2ba,
|
|
0x00b0bf8ca, 0x00bf80dd2, 0x123888b7a, 0x00167d312,
|
|
0x1e888f7dc, 0x18dcddd1c, 0x002ee03b2, 0x0f6076544,
|
|
0x183e8d8fe, 0x06a45d2b2, 0x133d7a042, 0x026f6a60a,
|
|
0x116b0f50c, 0x1dd3e10e8, 0x05fabe670, 0x1a2adb74e,
|
|
0x130004488, 0x0de87806c, 0x000bcf5f6, 0x19d34af3a,
|
|
0x18f0c7078, 0x014338754, 0x017f27698, 0x049c3cc9c,
|
|
0x058ca5f00, 0x15e3e77ee, 0x1af900c24, 0x068bce87a,
|
|
0x0b5cfca28, 0x0dd07448e, 0x0ded288f8, 0x1524fa6c6,
|
|
0x059f229bc, 0x1d8048348, 0x06d390dec, 0x16cba8aca,
|
|
0x037170390, 0x0a3e3e02c, 0x06353c1cc, 0x042d98888,
|
|
0x0c4584f5c, 0x0d73c7bea, 0x1f16a3418, 0x1329d9f7e,
|
|
0x0531377e2, 0x185137662, 0x1d8d9ca7c, 0x1b1c69528,
|
|
0x0b25b29f2, 0x18a08b5bc, 0x19fb2a8b0, 0x02178513a,
|
|
0x1a08fe6ac, 0x1da758ae0, 0x045cddf4e, 0x0e0ac139e,
|
|
0x1a91647f2, 0x169cf9eb0, 0x1a0f717c4, 0x0170076fa,
|
|
};
|
|
|
|
// Compute the crc32c value for buffer smaller than 8
|
|
#ifdef ROCKSDB_UBSAN_RUN
|
|
#if defined(__clang__)
|
|
__attribute__((__no_sanitize__("alignment")))
|
|
#elif defined(__GNUC__)
|
|
__attribute__((__no_sanitize_undefined__))
|
|
#endif
|
|
#endif
|
|
inline void align_to_8(
|
|
size_t len,
|
|
uint64_t& crc0, // crc so far, updated on return
|
|
const unsigned char*& next) { // next data pointer, updated on return
|
|
uint32_t crc32bit = static_cast<uint32_t>(crc0);
|
|
if (len & 0x04) {
|
|
crc32bit = _mm_crc32_u32(crc32bit, *(uint32_t*)next);
|
|
next += sizeof(uint32_t);
|
|
}
|
|
if (len & 0x02) {
|
|
crc32bit = _mm_crc32_u16(crc32bit, *(uint16_t*)next);
|
|
next += sizeof(uint16_t);
|
|
}
|
|
if (len & 0x01) {
|
|
crc32bit = _mm_crc32_u8(crc32bit, *(next));
|
|
next++;
|
|
}
|
|
crc0 = crc32bit;
|
|
}
|
|
|
|
//
|
|
// CombineCRC performs pclmulqdq multiplication of 2 partial CRC's and a well
|
|
// chosen constant and xor's these with the remaining CRC.
|
|
//
|
|
inline uint64_t CombineCRC(
|
|
size_t block_size,
|
|
uint64_t crc0,
|
|
uint64_t crc1,
|
|
uint64_t crc2,
|
|
const uint64_t* next2) {
|
|
const auto multiplier =
|
|
*(reinterpret_cast<const __m128i*>(clmul_constants) + block_size - 1);
|
|
const auto crc0_xmm = _mm_set_epi64x(0, crc0);
|
|
const auto res0 = _mm_clmulepi64_si128(crc0_xmm, multiplier, 0x00);
|
|
const auto crc1_xmm = _mm_set_epi64x(0, crc1);
|
|
const auto res1 = _mm_clmulepi64_si128(crc1_xmm, multiplier, 0x10);
|
|
const auto res = _mm_xor_si128(res0, res1);
|
|
crc0 = _mm_cvtsi128_si64(res);
|
|
crc0 = crc0 ^ *((uint64_t*)next2 - 1);
|
|
crc2 = _mm_crc32_u64(crc2, crc0);
|
|
return crc2;
|
|
}
|
|
|
|
// Compute CRC-32C using the Intel hardware instruction.
|
|
#ifdef ROCKSDB_UBSAN_RUN
|
|
#if defined(__clang__)
|
|
__attribute__((__no_sanitize__("alignment")))
|
|
#elif defined(__GNUC__)
|
|
__attribute__((__no_sanitize_undefined__))
|
|
#endif
|
|
#endif
|
|
uint32_t crc32c_3way(uint32_t crc, const char* buf, size_t len) {
|
|
const unsigned char* next = (const unsigned char*)buf;
|
|
uint64_t count;
|
|
uint64_t crc0, crc1, crc2;
|
|
crc0 = crc ^ 0xffffffffu;
|
|
|
|
|
|
if (len >= 8) {
|
|
// if len > 216 then align and use triplets
|
|
if (len > 216) {
|
|
{
|
|
// Work on the bytes (< 8) before the first 8-byte alignment addr starts
|
|
uint64_t align_bytes = (8 - (uintptr_t)next) & 7;
|
|
len -= align_bytes;
|
|
align_to_8(align_bytes, crc0, next);
|
|
}
|
|
|
|
// Now work on the remaining blocks
|
|
count = len / 24; // number of triplets
|
|
len %= 24; // bytes remaining
|
|
uint64_t n = count >> 7; // #blocks = first block + full blocks
|
|
uint64_t block_size = count & 127;
|
|
if (block_size == 0) {
|
|
block_size = 128;
|
|
} else {
|
|
n++;
|
|
}
|
|
// points to the first byte of the next block
|
|
const uint64_t* next0 = (uint64_t*)next + block_size;
|
|
const uint64_t* next1 = next0 + block_size;
|
|
const uint64_t* next2 = next1 + block_size;
|
|
|
|
crc1 = crc2 = 0;
|
|
// Use Duff's device, a for() loop inside a switch()
|
|
// statement. This needs to execute at least once, round len
|
|
// down to nearest triplet multiple
|
|
switch (block_size) {
|
|
case 128:
|
|
do {
|
|
// jumps here for a full block of len 128
|
|
CRCtriplet(crc, next, -128);
|
|
FALLTHROUGH_INTENDED;
|
|
case 127:
|
|
// jumps here or below for the first block smaller
|
|
CRCtriplet(crc, next, -127);
|
|
FALLTHROUGH_INTENDED;
|
|
case 126:
|
|
CRCtriplet(crc, next, -126); // than 128
|
|
FALLTHROUGH_INTENDED;
|
|
case 125:
|
|
CRCtriplet(crc, next, -125);
|
|
FALLTHROUGH_INTENDED;
|
|
case 124:
|
|
CRCtriplet(crc, next, -124);
|
|
FALLTHROUGH_INTENDED;
|
|
case 123:
|
|
CRCtriplet(crc, next, -123);
|
|
FALLTHROUGH_INTENDED;
|
|
case 122:
|
|
CRCtriplet(crc, next, -122);
|
|
FALLTHROUGH_INTENDED;
|
|
case 121:
|
|
CRCtriplet(crc, next, -121);
|
|
FALLTHROUGH_INTENDED;
|
|
case 120:
|
|
CRCtriplet(crc, next, -120);
|
|
FALLTHROUGH_INTENDED;
|
|
case 119:
|
|
CRCtriplet(crc, next, -119);
|
|
FALLTHROUGH_INTENDED;
|
|
case 118:
|
|
CRCtriplet(crc, next, -118);
|
|
FALLTHROUGH_INTENDED;
|
|
case 117:
|
|
CRCtriplet(crc, next, -117);
|
|
FALLTHROUGH_INTENDED;
|
|
case 116:
|
|
CRCtriplet(crc, next, -116);
|
|
FALLTHROUGH_INTENDED;
|
|
case 115:
|
|
CRCtriplet(crc, next, -115);
|
|
FALLTHROUGH_INTENDED;
|
|
case 114:
|
|
CRCtriplet(crc, next, -114);
|
|
FALLTHROUGH_INTENDED;
|
|
case 113:
|
|
CRCtriplet(crc, next, -113);
|
|
FALLTHROUGH_INTENDED;
|
|
case 112:
|
|
CRCtriplet(crc, next, -112);
|
|
FALLTHROUGH_INTENDED;
|
|
case 111:
|
|
CRCtriplet(crc, next, -111);
|
|
FALLTHROUGH_INTENDED;
|
|
case 110:
|
|
CRCtriplet(crc, next, -110);
|
|
FALLTHROUGH_INTENDED;
|
|
case 109:
|
|
CRCtriplet(crc, next, -109);
|
|
FALLTHROUGH_INTENDED;
|
|
case 108:
|
|
CRCtriplet(crc, next, -108);
|
|
FALLTHROUGH_INTENDED;
|
|
case 107:
|
|
CRCtriplet(crc, next, -107);
|
|
FALLTHROUGH_INTENDED;
|
|
case 106:
|
|
CRCtriplet(crc, next, -106);
|
|
FALLTHROUGH_INTENDED;
|
|
case 105:
|
|
CRCtriplet(crc, next, -105);
|
|
FALLTHROUGH_INTENDED;
|
|
case 104:
|
|
CRCtriplet(crc, next, -104);
|
|
FALLTHROUGH_INTENDED;
|
|
case 103:
|
|
CRCtriplet(crc, next, -103);
|
|
FALLTHROUGH_INTENDED;
|
|
case 102:
|
|
CRCtriplet(crc, next, -102);
|
|
FALLTHROUGH_INTENDED;
|
|
case 101:
|
|
CRCtriplet(crc, next, -101);
|
|
FALLTHROUGH_INTENDED;
|
|
case 100:
|
|
CRCtriplet(crc, next, -100);
|
|
FALLTHROUGH_INTENDED;
|
|
case 99:
|
|
CRCtriplet(crc, next, -99);
|
|
FALLTHROUGH_INTENDED;
|
|
case 98:
|
|
CRCtriplet(crc, next, -98);
|
|
FALLTHROUGH_INTENDED;
|
|
case 97:
|
|
CRCtriplet(crc, next, -97);
|
|
FALLTHROUGH_INTENDED;
|
|
case 96:
|
|
CRCtriplet(crc, next, -96);
|
|
FALLTHROUGH_INTENDED;
|
|
case 95:
|
|
CRCtriplet(crc, next, -95);
|
|
FALLTHROUGH_INTENDED;
|
|
case 94:
|
|
CRCtriplet(crc, next, -94);
|
|
FALLTHROUGH_INTENDED;
|
|
case 93:
|
|
CRCtriplet(crc, next, -93);
|
|
FALLTHROUGH_INTENDED;
|
|
case 92:
|
|
CRCtriplet(crc, next, -92);
|
|
FALLTHROUGH_INTENDED;
|
|
case 91:
|
|
CRCtriplet(crc, next, -91);
|
|
FALLTHROUGH_INTENDED;
|
|
case 90:
|
|
CRCtriplet(crc, next, -90);
|
|
FALLTHROUGH_INTENDED;
|
|
case 89:
|
|
CRCtriplet(crc, next, -89);
|
|
FALLTHROUGH_INTENDED;
|
|
case 88:
|
|
CRCtriplet(crc, next, -88);
|
|
FALLTHROUGH_INTENDED;
|
|
case 87:
|
|
CRCtriplet(crc, next, -87);
|
|
FALLTHROUGH_INTENDED;
|
|
case 86:
|
|
CRCtriplet(crc, next, -86);
|
|
FALLTHROUGH_INTENDED;
|
|
case 85:
|
|
CRCtriplet(crc, next, -85);
|
|
FALLTHROUGH_INTENDED;
|
|
case 84:
|
|
CRCtriplet(crc, next, -84);
|
|
FALLTHROUGH_INTENDED;
|
|
case 83:
|
|
CRCtriplet(crc, next, -83);
|
|
FALLTHROUGH_INTENDED;
|
|
case 82:
|
|
CRCtriplet(crc, next, -82);
|
|
FALLTHROUGH_INTENDED;
|
|
case 81:
|
|
CRCtriplet(crc, next, -81);
|
|
FALLTHROUGH_INTENDED;
|
|
case 80:
|
|
CRCtriplet(crc, next, -80);
|
|
FALLTHROUGH_INTENDED;
|
|
case 79:
|
|
CRCtriplet(crc, next, -79);
|
|
FALLTHROUGH_INTENDED;
|
|
case 78:
|
|
CRCtriplet(crc, next, -78);
|
|
FALLTHROUGH_INTENDED;
|
|
case 77:
|
|
CRCtriplet(crc, next, -77);
|
|
FALLTHROUGH_INTENDED;
|
|
case 76:
|
|
CRCtriplet(crc, next, -76);
|
|
FALLTHROUGH_INTENDED;
|
|
case 75:
|
|
CRCtriplet(crc, next, -75);
|
|
FALLTHROUGH_INTENDED;
|
|
case 74:
|
|
CRCtriplet(crc, next, -74);
|
|
FALLTHROUGH_INTENDED;
|
|
case 73:
|
|
CRCtriplet(crc, next, -73);
|
|
FALLTHROUGH_INTENDED;
|
|
case 72:
|
|
CRCtriplet(crc, next, -72);
|
|
FALLTHROUGH_INTENDED;
|
|
case 71:
|
|
CRCtriplet(crc, next, -71);
|
|
FALLTHROUGH_INTENDED;
|
|
case 70:
|
|
CRCtriplet(crc, next, -70);
|
|
FALLTHROUGH_INTENDED;
|
|
case 69:
|
|
CRCtriplet(crc, next, -69);
|
|
FALLTHROUGH_INTENDED;
|
|
case 68:
|
|
CRCtriplet(crc, next, -68);
|
|
FALLTHROUGH_INTENDED;
|
|
case 67:
|
|
CRCtriplet(crc, next, -67);
|
|
FALLTHROUGH_INTENDED;
|
|
case 66:
|
|
CRCtriplet(crc, next, -66);
|
|
FALLTHROUGH_INTENDED;
|
|
case 65:
|
|
CRCtriplet(crc, next, -65);
|
|
FALLTHROUGH_INTENDED;
|
|
case 64:
|
|
CRCtriplet(crc, next, -64);
|
|
FALLTHROUGH_INTENDED;
|
|
case 63:
|
|
CRCtriplet(crc, next, -63);
|
|
FALLTHROUGH_INTENDED;
|
|
case 62:
|
|
CRCtriplet(crc, next, -62);
|
|
FALLTHROUGH_INTENDED;
|
|
case 61:
|
|
CRCtriplet(crc, next, -61);
|
|
FALLTHROUGH_INTENDED;
|
|
case 60:
|
|
CRCtriplet(crc, next, -60);
|
|
FALLTHROUGH_INTENDED;
|
|
case 59:
|
|
CRCtriplet(crc, next, -59);
|
|
FALLTHROUGH_INTENDED;
|
|
case 58:
|
|
CRCtriplet(crc, next, -58);
|
|
FALLTHROUGH_INTENDED;
|
|
case 57:
|
|
CRCtriplet(crc, next, -57);
|
|
FALLTHROUGH_INTENDED;
|
|
case 56:
|
|
CRCtriplet(crc, next, -56);
|
|
FALLTHROUGH_INTENDED;
|
|
case 55:
|
|
CRCtriplet(crc, next, -55);
|
|
FALLTHROUGH_INTENDED;
|
|
case 54:
|
|
CRCtriplet(crc, next, -54);
|
|
FALLTHROUGH_INTENDED;
|
|
case 53:
|
|
CRCtriplet(crc, next, -53);
|
|
FALLTHROUGH_INTENDED;
|
|
case 52:
|
|
CRCtriplet(crc, next, -52);
|
|
FALLTHROUGH_INTENDED;
|
|
case 51:
|
|
CRCtriplet(crc, next, -51);
|
|
FALLTHROUGH_INTENDED;
|
|
case 50:
|
|
CRCtriplet(crc, next, -50);
|
|
FALLTHROUGH_INTENDED;
|
|
case 49:
|
|
CRCtriplet(crc, next, -49);
|
|
FALLTHROUGH_INTENDED;
|
|
case 48:
|
|
CRCtriplet(crc, next, -48);
|
|
FALLTHROUGH_INTENDED;
|
|
case 47:
|
|
CRCtriplet(crc, next, -47);
|
|
FALLTHROUGH_INTENDED;
|
|
case 46:
|
|
CRCtriplet(crc, next, -46);
|
|
FALLTHROUGH_INTENDED;
|
|
case 45:
|
|
CRCtriplet(crc, next, -45);
|
|
FALLTHROUGH_INTENDED;
|
|
case 44:
|
|
CRCtriplet(crc, next, -44);
|
|
FALLTHROUGH_INTENDED;
|
|
case 43:
|
|
CRCtriplet(crc, next, -43);
|
|
FALLTHROUGH_INTENDED;
|
|
case 42:
|
|
CRCtriplet(crc, next, -42);
|
|
FALLTHROUGH_INTENDED;
|
|
case 41:
|
|
CRCtriplet(crc, next, -41);
|
|
FALLTHROUGH_INTENDED;
|
|
case 40:
|
|
CRCtriplet(crc, next, -40);
|
|
FALLTHROUGH_INTENDED;
|
|
case 39:
|
|
CRCtriplet(crc, next, -39);
|
|
FALLTHROUGH_INTENDED;
|
|
case 38:
|
|
CRCtriplet(crc, next, -38);
|
|
FALLTHROUGH_INTENDED;
|
|
case 37:
|
|
CRCtriplet(crc, next, -37);
|
|
FALLTHROUGH_INTENDED;
|
|
case 36:
|
|
CRCtriplet(crc, next, -36);
|
|
FALLTHROUGH_INTENDED;
|
|
case 35:
|
|
CRCtriplet(crc, next, -35);
|
|
FALLTHROUGH_INTENDED;
|
|
case 34:
|
|
CRCtriplet(crc, next, -34);
|
|
FALLTHROUGH_INTENDED;
|
|
case 33:
|
|
CRCtriplet(crc, next, -33);
|
|
FALLTHROUGH_INTENDED;
|
|
case 32:
|
|
CRCtriplet(crc, next, -32);
|
|
FALLTHROUGH_INTENDED;
|
|
case 31:
|
|
CRCtriplet(crc, next, -31);
|
|
FALLTHROUGH_INTENDED;
|
|
case 30:
|
|
CRCtriplet(crc, next, -30);
|
|
FALLTHROUGH_INTENDED;
|
|
case 29:
|
|
CRCtriplet(crc, next, -29);
|
|
FALLTHROUGH_INTENDED;
|
|
case 28:
|
|
CRCtriplet(crc, next, -28);
|
|
FALLTHROUGH_INTENDED;
|
|
case 27:
|
|
CRCtriplet(crc, next, -27);
|
|
FALLTHROUGH_INTENDED;
|
|
case 26:
|
|
CRCtriplet(crc, next, -26);
|
|
FALLTHROUGH_INTENDED;
|
|
case 25:
|
|
CRCtriplet(crc, next, -25);
|
|
FALLTHROUGH_INTENDED;
|
|
case 24:
|
|
CRCtriplet(crc, next, -24);
|
|
FALLTHROUGH_INTENDED;
|
|
case 23:
|
|
CRCtriplet(crc, next, -23);
|
|
FALLTHROUGH_INTENDED;
|
|
case 22:
|
|
CRCtriplet(crc, next, -22);
|
|
FALLTHROUGH_INTENDED;
|
|
case 21:
|
|
CRCtriplet(crc, next, -21);
|
|
FALLTHROUGH_INTENDED;
|
|
case 20:
|
|
CRCtriplet(crc, next, -20);
|
|
FALLTHROUGH_INTENDED;
|
|
case 19:
|
|
CRCtriplet(crc, next, -19);
|
|
FALLTHROUGH_INTENDED;
|
|
case 18:
|
|
CRCtriplet(crc, next, -18);
|
|
FALLTHROUGH_INTENDED;
|
|
case 17:
|
|
CRCtriplet(crc, next, -17);
|
|
FALLTHROUGH_INTENDED;
|
|
case 16:
|
|
CRCtriplet(crc, next, -16);
|
|
FALLTHROUGH_INTENDED;
|
|
case 15:
|
|
CRCtriplet(crc, next, -15);
|
|
FALLTHROUGH_INTENDED;
|
|
case 14:
|
|
CRCtriplet(crc, next, -14);
|
|
FALLTHROUGH_INTENDED;
|
|
case 13:
|
|
CRCtriplet(crc, next, -13);
|
|
FALLTHROUGH_INTENDED;
|
|
case 12:
|
|
CRCtriplet(crc, next, -12);
|
|
FALLTHROUGH_INTENDED;
|
|
case 11:
|
|
CRCtriplet(crc, next, -11);
|
|
FALLTHROUGH_INTENDED;
|
|
case 10:
|
|
CRCtriplet(crc, next, -10);
|
|
FALLTHROUGH_INTENDED;
|
|
case 9:
|
|
CRCtriplet(crc, next, -9);
|
|
FALLTHROUGH_INTENDED;
|
|
case 8:
|
|
CRCtriplet(crc, next, -8);
|
|
FALLTHROUGH_INTENDED;
|
|
case 7:
|
|
CRCtriplet(crc, next, -7);
|
|
FALLTHROUGH_INTENDED;
|
|
case 6:
|
|
CRCtriplet(crc, next, -6);
|
|
FALLTHROUGH_INTENDED;
|
|
case 5:
|
|
CRCtriplet(crc, next, -5);
|
|
FALLTHROUGH_INTENDED;
|
|
case 4:
|
|
CRCtriplet(crc, next, -4);
|
|
FALLTHROUGH_INTENDED;
|
|
case 3:
|
|
CRCtriplet(crc, next, -3);
|
|
FALLTHROUGH_INTENDED;
|
|
case 2:
|
|
CRCtriplet(crc, next, -2);
|
|
FALLTHROUGH_INTENDED;
|
|
case 1:
|
|
CRCduplet(crc, next, -1); // the final triplet is actually only 2
|
|
//{ CombineCRC(); }
|
|
crc0 = CombineCRC(block_size, crc0, crc1, crc2, next2);
|
|
if (--n > 0) {
|
|
crc1 = crc2 = 0;
|
|
block_size = 128;
|
|
// points to the first byte of the next block
|
|
next0 = next2 + 128;
|
|
next1 = next0 + 128; // from here on all blocks are 128 long
|
|
next2 = next1 + 128;
|
|
}
|
|
FALLTHROUGH_INTENDED;
|
|
case 0:;
|
|
} while (n > 0);
|
|
}
|
|
next = (const unsigned char*)next2;
|
|
}
|
|
uint64_t count2 = len >> 3; // 216 of less bytes is 27 or less singlets
|
|
len = len & 7;
|
|
next += (count2 * 8);
|
|
switch (count2) {
|
|
case 27:
|
|
CRCsinglet(crc0, next, -27 * 8);
|
|
FALLTHROUGH_INTENDED;
|
|
case 26:
|
|
CRCsinglet(crc0, next, -26 * 8);
|
|
FALLTHROUGH_INTENDED;
|
|
case 25:
|
|
CRCsinglet(crc0, next, -25 * 8);
|
|
FALLTHROUGH_INTENDED;
|
|
case 24:
|
|
CRCsinglet(crc0, next, -24 * 8);
|
|
FALLTHROUGH_INTENDED;
|
|
case 23:
|
|
CRCsinglet(crc0, next, -23 * 8);
|
|
FALLTHROUGH_INTENDED;
|
|
case 22:
|
|
CRCsinglet(crc0, next, -22 * 8);
|
|
FALLTHROUGH_INTENDED;
|
|
case 21:
|
|
CRCsinglet(crc0, next, -21 * 8);
|
|
FALLTHROUGH_INTENDED;
|
|
case 20:
|
|
CRCsinglet(crc0, next, -20 * 8);
|
|
FALLTHROUGH_INTENDED;
|
|
case 19:
|
|
CRCsinglet(crc0, next, -19 * 8);
|
|
FALLTHROUGH_INTENDED;
|
|
case 18:
|
|
CRCsinglet(crc0, next, -18 * 8);
|
|
FALLTHROUGH_INTENDED;
|
|
case 17:
|
|
CRCsinglet(crc0, next, -17 * 8);
|
|
FALLTHROUGH_INTENDED;
|
|
case 16:
|
|
CRCsinglet(crc0, next, -16 * 8);
|
|
FALLTHROUGH_INTENDED;
|
|
case 15:
|
|
CRCsinglet(crc0, next, -15 * 8);
|
|
FALLTHROUGH_INTENDED;
|
|
case 14:
|
|
CRCsinglet(crc0, next, -14 * 8);
|
|
FALLTHROUGH_INTENDED;
|
|
case 13:
|
|
CRCsinglet(crc0, next, -13 * 8);
|
|
FALLTHROUGH_INTENDED;
|
|
case 12:
|
|
CRCsinglet(crc0, next, -12 * 8);
|
|
FALLTHROUGH_INTENDED;
|
|
case 11:
|
|
CRCsinglet(crc0, next, -11 * 8);
|
|
FALLTHROUGH_INTENDED;
|
|
case 10:
|
|
CRCsinglet(crc0, next, -10 * 8);
|
|
FALLTHROUGH_INTENDED;
|
|
case 9:
|
|
CRCsinglet(crc0, next, -9 * 8);
|
|
FALLTHROUGH_INTENDED;
|
|
case 8:
|
|
CRCsinglet(crc0, next, -8 * 8);
|
|
FALLTHROUGH_INTENDED;
|
|
case 7:
|
|
CRCsinglet(crc0, next, -7 * 8);
|
|
FALLTHROUGH_INTENDED;
|
|
case 6:
|
|
CRCsinglet(crc0, next, -6 * 8);
|
|
FALLTHROUGH_INTENDED;
|
|
case 5:
|
|
CRCsinglet(crc0, next, -5 * 8);
|
|
FALLTHROUGH_INTENDED;
|
|
case 4:
|
|
CRCsinglet(crc0, next, -4 * 8);
|
|
FALLTHROUGH_INTENDED;
|
|
case 3:
|
|
CRCsinglet(crc0, next, -3 * 8);
|
|
FALLTHROUGH_INTENDED;
|
|
case 2:
|
|
CRCsinglet(crc0, next, -2 * 8);
|
|
FALLTHROUGH_INTENDED;
|
|
case 1:
|
|
CRCsinglet(crc0, next, -1 * 8);
|
|
FALLTHROUGH_INTENDED;
|
|
case 0:;
|
|
}
|
|
}
|
|
{
|
|
align_to_8(len, crc0, next);
|
|
return (uint32_t)crc0 ^ 0xffffffffu;
|
|
}
|
|
}
|
|
|
|
#endif //__SSE4_2__ && __PCLMUL__
|
|
|
|
static inline Function Choose_Extend() {
|
|
#ifdef HAVE_POWER8
|
|
return isAltiVec() ? ExtendPPCImpl : ExtendImpl<DefaultCRC32>;
|
|
#elif defined(HAVE_ARM64_CRC)
|
|
if(crc32c_runtime_check()) {
|
|
pmull_runtime_flag = crc32c_pmull_runtime_check();
|
|
return ExtendARMImpl;
|
|
} else {
|
|
return ExtendImpl<DefaultCRC32>;
|
|
}
|
|
#elif defined(__SSE4_2__) && defined(__PCLMUL__) && !defined NO_THREEWAY_CRC32C
|
|
// NOTE: runtime detection no longer supported on x86
|
|
(void)ExtendImpl<DefaultCRC32>; // suppress unused warning
|
|
return crc32c_3way;
|
|
#else
|
|
return ExtendImpl<DefaultCRC32>;
|
|
#endif
|
|
}
|
|
|
|
static Function ChosenExtend = Choose_Extend();
|
|
uint32_t Extend(uint32_t crc, const char* buf, size_t size) {
|
|
return ChosenExtend(crc, buf, size);
|
|
}
|
|
|
|
// The code for crc32c combine, copied with permission from folly
|
|
|
|
// Standard galois-field multiply. The only modification is that a,
|
|
// b, m, and p are all bit-reflected.
|
|
//
|
|
// https://en.wikipedia.org/wiki/Finite_field_arithmetic
|
|
static constexpr uint32_t gf_multiply_sw_1(
|
|
size_t i, uint32_t p, uint32_t a, uint32_t b, uint32_t m) {
|
|
// clang-format off
|
|
return i == 32 ? p : gf_multiply_sw_1(
|
|
/* i = */ i + 1,
|
|
/* p = */ p ^ ((0u-((b >> 31) & 1)) & a),
|
|
/* a = */ (a >> 1) ^ ((0u-(a & 1)) & m),
|
|
/* b = */ b << 1,
|
|
/* m = */ m);
|
|
// clang-format on
|
|
}
|
|
static constexpr uint32_t gf_multiply_sw(uint32_t a, uint32_t b, uint32_t m) {
|
|
return gf_multiply_sw_1(/* i = */ 0, /* p = */ 0, a, b, m);
|
|
}
|
|
|
|
static constexpr uint32_t gf_square_sw(uint32_t a, uint32_t m) {
|
|
return gf_multiply_sw(a, a, m);
|
|
}
|
|
|
|
template <size_t i, uint32_t m>
|
|
struct gf_powers_memo {
|
|
static constexpr uint32_t value =
|
|
gf_square_sw(gf_powers_memo<i - 1, m>::value, m);
|
|
};
|
|
template <uint32_t m>
|
|
struct gf_powers_memo<0, m> {
|
|
static constexpr uint32_t value = m;
|
|
};
|
|
|
|
template <typename T, T... Ints>
|
|
struct integer_sequence {
|
|
using value_type = T;
|
|
static constexpr size_t size() { return sizeof...(Ints); }
|
|
};
|
|
|
|
template <typename T, std::size_t N, T... Is>
|
|
struct make_integer_sequence : make_integer_sequence<T, N - 1, N - 1, Is...> {};
|
|
|
|
template <typename T, T... Is>
|
|
struct make_integer_sequence<T, 0, Is...> : integer_sequence<T, Is...> {};
|
|
|
|
template <std::size_t N>
|
|
using make_index_sequence = make_integer_sequence<std::size_t, N>;
|
|
|
|
template <uint32_t m>
|
|
struct gf_powers_make {
|
|
template <size_t... i>
|
|
using index_sequence = integer_sequence<size_t, i...>;
|
|
template <size_t... i>
|
|
constexpr std::array<uint32_t, sizeof...(i)> operator()(
|
|
index_sequence<i...>) const {
|
|
return std::array<uint32_t, sizeof...(i)>{{gf_powers_memo<i, m>::value...}};
|
|
}
|
|
};
|
|
|
|
static constexpr uint32_t crc32c_m = 0x82f63b78;
|
|
|
|
static constexpr std::array<uint32_t, 62> const crc32c_powers =
|
|
gf_powers_make<crc32c_m>{}(make_index_sequence<62>{});
|
|
|
|
// Expects a "pure" crc (see Crc32cCombine)
|
|
static uint32_t Crc32AppendZeroes(
|
|
uint32_t crc, size_t len_over_4, uint32_t polynomial,
|
|
std::array<uint32_t, 62> const& powers_array) {
|
|
auto powers = powers_array.data();
|
|
// Append by multiplying by consecutive powers of two of the zeroes
|
|
// array
|
|
size_t len_bits = len_over_4;
|
|
|
|
while (len_bits) {
|
|
// Advance directly to next bit set.
|
|
auto r = CountTrailingZeroBits(len_bits);
|
|
len_bits >>= r;
|
|
powers += r;
|
|
|
|
crc = gf_multiply_sw(crc, *powers, polynomial);
|
|
|
|
len_bits >>= 1;
|
|
powers++;
|
|
}
|
|
|
|
return crc;
|
|
}
|
|
|
|
static inline uint32_t InvertedToPure(uint32_t crc) { return ~crc; }
|
|
|
|
static inline uint32_t PureToInverted(uint32_t crc) { return ~crc; }
|
|
|
|
static inline uint32_t PureExtend(uint32_t crc, const char* buf, size_t size) {
|
|
return InvertedToPure(Extend(PureToInverted(crc), buf, size));
|
|
}
|
|
|
|
// Background:
|
|
// RocksDB uses two kinds of crc32c values: masked and unmasked. Neither is
|
|
// a "pure" CRC because a pure CRC satisfies (^ for xor)
|
|
// crc(a ^ b) = crc(a) ^ crc(b)
|
|
// The unmasked is closest, and this function takes unmasked crc32c values.
|
|
// The unmasked values are impure in two ways:
|
|
// * The initial setting at the start of CRC computation is all 1 bits
|
|
// (like -1) instead of zero.
|
|
// * The result has all bits invered.
|
|
// Note that together, these result in the empty string having a crc32c of
|
|
// zero. See
|
|
// https://en.wikipedia.org/wiki/Computation_of_cyclic_redundancy_checks#CRC_variants
|
|
//
|
|
// Simplified version of strategy, using xor through pure CRCs (+ for concat):
|
|
//
|
|
// pure_crc(str1 + str2) = pure_crc(str1 + zeros(len(str2))) ^
|
|
// pure_crc(zeros(len(str1)) + str2)
|
|
//
|
|
// because the xor of these two zero-padded strings is str1 + str2. For pure
|
|
// CRC, leading zeros don't affect the result, so we only need
|
|
//
|
|
// pure_crc(str1 + str2) = pure_crc(str1 + zeros(len(str2))) ^
|
|
// pure_crc(str2)
|
|
//
|
|
// Considering we aren't working with pure CRCs, what is actually in the input?
|
|
//
|
|
// crc1 = PureToInverted(PureExtendCrc32c(-1, zeros, crc1len) ^
|
|
// PureCrc32c(str1, crc1len))
|
|
// crc2 = PureToInverted(PureExtendCrc32c(-1, zeros, crc2len) ^
|
|
// PureCrc32c(str2, crc2len))
|
|
//
|
|
// The result we want to compute is
|
|
// combined = PureToInverted(PureExtendCrc32c(PureExtendCrc32c(-1, zeros,
|
|
// crc1len) ^
|
|
// PureCrc32c(str1, crc1len),
|
|
// zeros, crc2len) ^
|
|
// PureCrc32c(str2, crc2len))
|
|
//
|
|
// Thus, in addition to extending crc1 over the length of str2 in (virtual)
|
|
// zeros, we need to cancel out the -1 initializer that was used in computing
|
|
// crc2. To cancel it out, we also need to extend it over crc2len in zeros.
|
|
// To simplify, since the end of str1 and that -1 initializer for crc2 are at
|
|
// the same logical position, we can combine them before we extend over the
|
|
// zeros.
|
|
uint32_t Crc32cCombine(uint32_t crc1, uint32_t crc2, size_t crc2len) {
|
|
uint32_t pure_crc1_with_init = InvertedToPure(crc1);
|
|
uint32_t pure_crc2_with_init = InvertedToPure(crc2);
|
|
uint32_t pure_crc2_init = static_cast<uint32_t>(-1);
|
|
|
|
// Append up to 32 bits of zeroes in the normal way
|
|
char zeros[4] = {0, 0, 0, 0};
|
|
auto len = crc2len & 3;
|
|
uint32_t tmp = pure_crc1_with_init ^ pure_crc2_init;
|
|
if (len) {
|
|
tmp = PureExtend(tmp, zeros, len);
|
|
}
|
|
return PureToInverted(
|
|
Crc32AppendZeroes(tmp, crc2len / 4, crc32c_m, crc32c_powers) ^
|
|
pure_crc2_with_init);
|
|
}
|
|
|
|
} // namespace crc32c
|
|
} // namespace ROCKSDB_NAMESPACE
|