Adam Retter b937be3779 Fix Compilation on ppc64le using Clang 11 (#7713) ...

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 https://github.com/antonblanchard/crc32-vpmsum/commit/ffc8018efc1e4f05d22a9fc8dde57109dd09368b#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

2020-12-01 11:21:44 -08:00

..

ppc-asm.h

Fix Compilation on ppc64le using Clang 11 (#7713)

2020-12-01 11:21:44 -08:00