Fix optional neon support

On Android, we detect neon support at runtime and switch implementations
based on that. This requires that some parts of skia are compiled with
-mfpu=neon.

To support this, the -mfpu flag is moved out of the 'compiler' config
and into its own config. A target can then remove this config and supply
its own -mfpu flag (without having to duplicate all the other stuff in
the 'compiler' config).

BUG=359249

Review URL: https://codereview.chromium.org/371853007

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@286038 0039d316-1c4b-4281-b951-d872f2087c98

1 files changed, 15 insertions, 8 deletions

diff --git a/skia/BUILD.gn b/skia/BUILD.gn
index 1a043ce..2b520e4 100644
--- a/skia/BUILD.gn
+++ b/skia/BUILD.gn
@@ -180,6 +180,15 @@ config("skia_library_config") {
     "SK_USE_DISCARDABLE_SCALEDIMAGECACHE",
   ]
 
+  if (cpu_arch == "arm") {
+    if (arm_use_neon) {
+      defines += [ "__ARM_HAVE_NEON" ]
+    }
+    if (arm_optionally_use_neon) {
+      defines += [ "__ARM_HAVE_OPTIONAL_NEON_SUPPORT" ]
+    }
+  }
+
   # Settings for text blitting, chosen to approximate the system browser.
   if (is_linux) {
     defines += [
@@ -626,20 +635,18 @@ source_set("skia_opts") {
 
         # Root build config sets -mfpu=$arm_fpu, which we expect to be neon
         # when running this.
-        assert(arm_fpu == "neon")
+        if (!arm_use_neon) {
+          configs -= [ "//build/config/compiler:compiler_arm_fpu" ]
+          cflags += [
+            "-mfpu=neon"
+          ]
+        }
 
         #ldflags = [
         #  "-march=armv7-a",
         #  "-Wl,--fix-cortex-a8",
         #]
       }
-
-      if (arm_use_neon) {
-        defines += [ "__ARM_HAVE_NEON" ]
-      }
-      if (arm_optionally_use_neon) {
-        defines += [ "__ARM_HAVE_OPTIONAL_NEON_SUPPORT" ]
-      }
     }
 
     # Non-Neon ARM code.