Attempt to let skia's SSE files build with clang-cl.

skia/skia_library_opts.gyp

 # Copyright 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.
 
 
 # This gyp file contains the platform-specific optimizations for Skia
 {
   'targets': [
     # Due to an unfortunate intersection of lameness between gcc and gyp,

[Reid Kleckner, 2014/08/15 00:40:02]

I feel guilty for propagating this "lameness" to clang.  Oh well. :)

     # we have to build the *_SSE2.cpp files in a separate target.  The
     # gcc lameness is that, in order to compile SSE2 intrinsics code, it
     # must be passed the -msse2 flag.  However, with this flag, it may
     # emit SSE2 instructions even for scalar code, such as the CPUID
     # test used to test for the presence of SSE2.  So that, and all other
     # code must be compiled *without* -msse2.  The gyp lameness is that it
     # does not allow file-specific CFLAGS, so we must create this extra
     # target for those files to be compiled with -msse2.
     #
     # This is actually only a problem on 32-bit Linux (all Intel Macs have
@@ skipping 150 matching lines @@
         [ 'OS in ["linux", "freebsd", "openbsd", "solaris", "android"]', {
           'cflags': [
             '-mssse3',
           ],
         }],
         [ 'OS == "mac"', {
           'xcode_settings': {
             'GCC_ENABLE_SUPPLEMENTAL_SSE3_INSTRUCTIONS': 'YES',
           },
         }],
+        [ 'OS == "win" and clang == 1', {
+          # cl.exe's /arch flag doesn't have a setting for SSSE3, and cl.exe
+          # doesn't need it for intrinsics. clang-cl does need it, though.
+          'msvs_settings': {
+            'VCCLCompilerTool': { 'AdditionalOptions': [ '-mssse3' ] },
+          },
+        }],
         [ 'OS == "win"', {
           'include_dirs': [
             'config/win',
           ],
           'direct_dependent_settings': {
             'include_dirs': [
               'config/win',
             ],
           },
           'defines' : [
@@ skipping 29 matching lines @@
         [ 'OS in ["linux", "freebsd", "openbsd", "solaris", "android"]', {
           'cflags': [
             '-msse4.1',
           ],
         }],
         [ 'OS == "mac"', {
           'xcode_settings': {
             'GCC_ENABLE_SSE41_EXTENSIONS': 'YES',
           },
         }],
+        [ 'OS == "win" and clang == 1', {
+          # cl.exe's /arch flag doesn't have a setting for SSE4.1, and cl.exe
+          # doesn't need it for intrinsics. clang-cl does need it, though.
+          'msvs_settings': {
+            'VCCLCompilerTool': { 'AdditionalOptions': [ '-msse4.1' ] },
+          },
+        }],
         [ 'OS == "win"', {
           'defines' : [
             'SK_CPU_SSE_LEVEL=41'
           ],
         }],
         [ 'target_arch == "x64"', {
           'sources': [
             '../third_party/skia/src/opts/SkBlitRow_opts_SSE4_x64_asm.S',
           ],
         }],
@@ skipping 74 matching lines @@
             '../third_party/skia/src/opts/SkTextureCompression_opts_neon.cpp',
             '../third_party/skia/src/opts/SkXfermode_opts_arm_neon.cpp',
             '../third_party/skia/src/opts/memset16_neon.S',
             '../third_party/skia/src/opts/memset32_neon.S',
           ],
         },
       ],
     }],
   ],
 }