b937be3779
Summary:
Closes https://github.com/facebook/rocksdb/issues/7691
The optimised CRC code for PPC64le which was originally imported in https://github.com/facebook/rocksdb/pull/2353 is not compatible with Clang 11. It looks like the code most likely originated from https://github.com/antonblanchard/crc32-vpmsum.
The code relied on a GCC header file `ppc-asm.h` which is not available in Clang.
To solve this, I have taken the same approach as the the upstream project from which the CRC code came ffc8018efc (diff-ec3e62c56fbcddeb07230f2a4673c1abd7f0f1cc8e48a2aa560056cfc1b25d60) and simply imported a copy of the GCC header file into our code-base which will be used when Clang is the compiler on pcc64le.
**NOTE**: The new file `util/ppc-asm.h` may have licensing implications which I guess need to be approved by RocksDB/Facebook before this is merged
Pull Request resolved: https://github.com/facebook/rocksdb/pull/7713
Reviewed By: jay-zhuang
Differential Revision: D25222645
Pulled By: pdillinger
fbshipit-source-id: e3fec9136f26ce1eb7a027048bcf77a6cb3c769c
95 lines
2.5 KiB
C
95 lines
2.5 KiB
C
// Copyright (c) Facebook, Inc. and its affiliates. All Rights Reserved.
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// Copyright (c) 2017 International Business Machines Corp.
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// 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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#define CRC_TABLE
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#include <stdint.h>
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#include <stdlib.h>
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#include <strings.h>
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#include "util/crc32c_ppc_constants.h"
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#define VMX_ALIGN 16
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#define VMX_ALIGN_MASK (VMX_ALIGN - 1)
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#ifdef REFLECT
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static unsigned int crc32_align(unsigned int crc, unsigned char const *p,
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unsigned long len) {
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while (len--) crc = crc_table[(crc ^ *p++) & 0xff] ^ (crc >> 8);
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return crc;
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}
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#endif
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#ifdef HAVE_POWER8
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unsigned int __crc32_vpmsum(unsigned int crc, unsigned char const *p,
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unsigned long len);
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static uint32_t crc32_vpmsum(uint32_t crc, unsigned char const *data,
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size_t len) {
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unsigned int prealign;
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unsigned int tail;
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#ifdef CRC_XOR
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crc ^= 0xffffffff;
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#endif
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if (len < VMX_ALIGN + VMX_ALIGN_MASK) {
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crc = crc32_align(crc, data, (unsigned long)len);
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goto out;
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}
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if ((unsigned long)data & VMX_ALIGN_MASK) {
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prealign = VMX_ALIGN - ((unsigned long)data & VMX_ALIGN_MASK);
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crc = crc32_align(crc, data, prealign);
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len -= prealign;
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data += prealign;
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}
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crc = __crc32_vpmsum(crc, data, (unsigned long)len & ~VMX_ALIGN_MASK);
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tail = len & VMX_ALIGN_MASK;
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if (tail) {
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data += len & ~VMX_ALIGN_MASK;
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crc = crc32_align(crc, data, tail);
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}
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out:
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#ifdef CRC_XOR
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crc ^= 0xffffffff;
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#endif
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return crc;
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}
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/* This wrapper function works around the fact that crc32_vpmsum
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* does not gracefully handle the case where the data pointer is NULL. There
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* may be room for performance improvement here.
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*/
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uint32_t crc32c_ppc(uint32_t crc, unsigned char const *data, size_t len) {
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unsigned char *buf2;
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if (!data) {
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buf2 = (unsigned char *)malloc(len);
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bzero(buf2, len);
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crc = crc32_vpmsum(crc, buf2, len);
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free(buf2);
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} else {
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crc = crc32_vpmsum(crc, data, (unsigned long)len);
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}
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return crc;
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}
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#else /* HAVE_POWER8 */
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/* This symbol has to exist on non-ppc architectures (and on legacy
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* ppc systems using power7 or below) in order to compile properly
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* there, even though it won't be called.
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*/
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uint32_t crc32c_ppc(uint32_t crc, unsigned char const *data, size_t len) {
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return 0;
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}
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#endif /* HAVE_POWER8 */
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