Integrate SIMD optimisations for zlib

third_party/zlib/BUILD.gn

 # Copyright (c) 2013 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 config("zlib_config") {
   include_dirs = [ "." ]
 }
 
 static_library("zlib") {
   if (!is_win) {
@@ skipping 24 matching lines @@
     "mozzconf.h",
     "trees.c",
     "trees.h",
     "uncompr.c",
     "zconf.h",
     "zlib.h",
     "zutil.c",
     "zutil.h",
   ]
 
+  if (is_linux && (cpu_arch == "x86" || cpu_arch == "x64")) {
+     sources += [ "crc_folding.c",
+                  "fill_window_sse.c",
+                  "x86.c",
+                  "x86.h" ]
+     defines = [ "HAVE_SSE2",
+                  "CHECK_SSE2",
+                  "USE_SSE4_2_CRC_HASH",
+                  "HAVE_PCLMULQDQ" ]
+     cflags = ["-msse2", "-msse4.2", "-mpclmul"]

[agl, 2014/09/23 21:41:39]

These compiler flags allow the compiler to use the given instructions anywhere
in the code, which isn't viable because we don't know if we'll have them at
runtime.

+  }
+
   configs -= [ "//build/config/compiler:chromium_code" ]
   configs += [ "//build/config/compiler:no_chromium_code" ]
 
   direct_dependent_configs = [ ":zlib_config" ]
 }
 
 static_library("minizip") {
   sources = [
     "contrib/minizip/ioapi.c",
     "contrib/minizip/ioapi.h",
@@ skipping 36 matching lines @@
     "google/zip_internal.cc",
     "google/zip_internal.h",
     "google/zip_reader.cc",
     "google/zip_reader.h",
   ]
   deps = [
     ":minizip",
     "//base",
   ]
 }