Integrate SIMD optimisations for zlib

These optimisations have been published on zlib mailing list and at
https://github.com/jtkukunas/zlib/

This change merges the following optimisation patches:
- "For x86, add CPUID check."
- "Adds SSE2 optimized hash shifting to fill_window."
- "add SSE4.2 optimized hash function"
- "add PCLMULQDQ optimized CRC folding"

From Jim Kukunas <james.t.kukunas@linux.intel.com> and adapts them to the
current zlib version in Chromium.

The optimisations are enabled at runtime if all the necessary CPU features are
present. As the optimisations require extra cflags to enable the compiler to
use the instructions the optimisations are held in their own static library
with a stub implementation to allow linking on other platforms.

TEST=net_unittests(GZipUnitTest) passes, Chrome functions and performance
improvement seen on RoboHornet benchmark on Linux Desktop
BUG=401517

Review URL: https://codereview.chromium.org/552123005

Cr-Original-Commit-Position: refs/heads/master@{#300866}
Cr-Mirrored-From: https://chromium.googlesource.com/chromium/src
Cr-Mirrored-Commit: e045ec106de29562ae94eafccde49a7b73848471

1 files changed, 13 insertions, 0 deletions

diff --git a/deflate.h b/deflate.h
index 2fe6fd6..f5c7a8b 100644
--- a/deflate.h
+++ b/deflate.h
@@ -107,6 +107,8 @@ typedef struct internal_state {
     Byte  method;        /* STORED (for zip only) or DEFLATED */
     int   last_flush;    /* value of flush param for previous deflate call */
 
+    unsigned zalign(16) crc0[4 * 5];
+
                 /* used by deflate.c: */
 
     uInt  w_size;        /* LZ77 window size (32K by default) */
@@ -344,4 +346,15 @@ void ZLIB_INTERNAL _tr_stored_block OF((deflate_state *s, charf *buf,
               flush = _tr_tally(s, distance, length)
 #endif
 
+/* Functions that are SIMD optimised on x86 */
+void ZLIB_INTERNAL crc_fold_init(deflate_state* const s);
+void ZLIB_INTERNAL crc_fold_copy(deflate_state* const s,
+                                 unsigned char* dst,
+                                 const unsigned char* src,
+                                 long len);
+unsigned ZLIB_INTERNAL crc_fold_512to32(deflate_state* const s);
+
+Pos ZLIB_INTERNAL insert_string_sse(deflate_state* const s, const Pos str);
+void ZLIB_INTERNAL fill_window_sse(deflate_state* s);
+
 #endif /* DEFLATE_H */