Reland "Integrate SIMD optimisations for zlib"
This version uses a "pthread_once" implementation, using Windows
synchronisation primitives, imported from tcmalloc.
Previous CLs:
https://codereview.chromium.org/677713002/
https://codereview.chromium.org/552123005
This version of the CL also runs fine on Windows Server 2003.
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/678423002
Cr-Commit-Position: refs/heads/master@{#302799}
14 files changed
