Add a [rtc_]build_with_neon variable to unify conditions.

webrtc/modules/audio_coding/BUILD.gn

 # Copyright (c) 2014 The WebRTC project authors. All Rights Reserved.
 #
 # Use of this source code is governed by a BSD-style license
 # that can be found in the LICENSE file in the root of the source
 # tree. An additional intellectual property rights grant can be found
 # in the file PATENTS.  All contributing project authors may
 # be found in the AUTHORS file in the root of the source tree.
 
 import("//build/config/arm.gni")
 import("../../build/webrtc.gni")
@@ skipping 480 matching lines @@
     "codecs/isac/fix/source/entropy_coding.h",
     "codecs/isac/fix/source/fft.c",
     "codecs/isac/fix/source/fft.h",
     "codecs/isac/fix/source/filterbank_tables.c",
     "codecs/isac/fix/source/filterbank_tables.h",
     "codecs/isac/fix/source/filterbanks.c",
     "codecs/isac/fix/source/filters.c",
     "codecs/isac/fix/source/initialize.c",
     "codecs/isac/fix/source/isacfix.c",
     "codecs/isac/fix/source/lattice.c",
+    "codecs/isac/fix/source/lattice_c.c",
     "codecs/isac/fix/source/lpc_masking_model.c",
     "codecs/isac/fix/source/lpc_masking_model.h",
     "codecs/isac/fix/source/lpc_tables.c",
     "codecs/isac/fix/source/lpc_tables.h",
     "codecs/isac/fix/source/pitch_estimator.c",
     "codecs/isac/fix/source/pitch_estimator.h",
     "codecs/isac/fix/source/pitch_estimator_c.c",
     "codecs/isac/fix/source/pitch_filter.c",
     "codecs/isac/fix/source/pitch_filter_c.c",
     "codecs/isac/fix/source/pitch_gain_tables.c",
@@ skipping 18 matching lines @@
     "../..:common_inherited_config",
     ":isac_fix_config",
   ]
 
   deps = [
     ":audio_encoder_interface",
     "../../common_audio",
     "../../system_wrappers",
   ]
 
-  if (current_cpu == "arm64") {
+  if (rtc_build_with_neon) {
     deps += [ ":isac_neon" ]
   }
 
-  if (rtc_build_armv7_neon) {
-    deps += [ ":isac_neon" ]
-
-    # Enable compilation for the ARM v7 Neon instruction set. This is needed
-    # since //build/config/arm.gni only enables Neon for iOS, not Android.
-    # This provides the same functionality as webrtc/build/arm_neon.gypi.
-    # TODO(kjellander): Investigate if this can be moved into webrtc.gni or
-    # //build/config/arm.gni instead, to reduce code duplication.
-    # Remove the -mfpu=vfpv3-d16 cflag.
-    configs -= [ "//build/config/compiler:compiler_arm_fpu" ]
-    cflags = [ "-mfpu=neon" ]
-
+  if (current_cpu == "arm" && arm_version >= 7) {
     sources += [
       "codecs/isac/fix/source/lattice_armv7.S",
       "codecs/isac/fix/source/pitch_filter_armv6.S",
     ]
-    sources -= [ "codecs/isac/fix/source/pitch_filter_c.c" ]
+    sources -= [

[kjellander_webrtc, 2015/06/18 09:06:23]

I don't like the minus-entries for source listings, but I guess it's easier to
read this way.

+      "codecs/isac/fix/source/lattice_c.c",
+      "codecs/isac/fix/source/pitch_filter_c.c",
+    ]
   }
 
   if (current_cpu == "mipsel") {
     sources += [
       "codecs/isac/fix/source/entropy_coding_mips.c",
       "codecs/isac/fix/source/filters_mips.c",
       "codecs/isac/fix/source/lattice_mips.c",
       "codecs/isac/fix/source/pitch_estimator_mips.c",
       "codecs/isac/fix/source/transform_mips.c",
     ]
-    sources -= [ "codecs/isac/fix/source/pitch_estimator_c.c" ]
+    sources -= [
+      "codecs/isac/fix/source/lattice_c.c",
+      "codecs/isac/fix/source/pitch_estimator_c.c",
+    ]
     if (mips_dsp_rev > 0) {
       sources += [ "codecs/isac/fix/source/filterbanks_mips.c" ]
     }
     if (mips_dsp_rev > 1) {
       sources += [
         "codecs/isac/fix/source/lpc_masking_model_mips.c",
         "codecs/isac/fix/source/pitch_filter_mips.c",
       ]
       sources -= [ "codecs/isac/fix/source/pitch_filter_c.c" ]
     }
   }
-
-  if (!rtc_build_armv7_neon && current_cpu != "mipsel") {
-    sources += [ "codecs/isac/fix/source/lattice_c.c" ]
-  }
 }
 
-if (rtc_build_armv7_neon || current_cpu == "arm64") {
+if (rtc_build_with_neon) {
   source_set("isac_neon") {
     sources = [
       "codecs/isac/fix/source/entropy_coding_neon.c",
       "codecs/isac/fix/source/filters_neon.c",
       "codecs/isac/fix/source/lattice_neon.c",
       "codecs/isac/fix/source/transform_neon.c",
     ]
+    if (current_cpu != "arm64" || !is_clang) {

[kjellander_webrtc, 2015/06/18 09:06:23]

This was fixed in Clang r235243 and we're currently at r238013
(https://chromium.googlesource.com/chromium/src/+/441009c0b2454f93adf9d30a42ea...)

I posted in the bug asking for re-enabling this (no need in this CL).

[zhongwei, 2015/06/19 08:21:03]

I've posted the patch at: https://codereview.webrtc.org/1194773002/

+      # Disable AllpassFilter2FixDec16Neon function due to a clang bug.
+      # For more details refer to:
+      # https://code.google.com/p/webrtc/issues/detail?id=4567
+      sources += [ "codecs/isac/fix/source/filterbanks_neon.c" ]
+    }
 
-    if (rtc_build_armv7_neon) {
-      # Enable compilation for the ARM v7 Neon instruction set. This is needed
-      # since //build/config/arm.gni only enables Neon for iOS, not Android.
+    if (current_cpu != "arm64") {
+      # Enable compilation for the NEON instruction set. This is needed
+      # since //build/config/arm.gni only enables NEON for iOS, not Android.
       # This provides the same functionality as webrtc/build/arm_neon.gypi.
-      # TODO(kjellander): Investigate if this can be moved into webrtc.gni or
-      # //build/config/arm.gni instead, to reduce code duplication.
-      # Remove the -mfpu=vfpv3-d16 cflag.
       configs -= [ "//build/config/compiler:compiler_arm_fpu" ]
       cflags = [ "-mfpu=neon" ]
     }
 
-    if (current_cpu != "arm64" || !is_clang) {
-      # Disable AllpassFilter2FixDec16Neon function due to a clang bug.
-      # Refer more details at:
-      # https://code.google.com/p/webrtc/issues/detail?id=4567
-      sources += [ "codecs/isac/fix/source/filterbanks_neon.c" ]
-    }
-
-    # Disable LTO in audio_processing_neon target due to compiler bug.
+    # Disable LTO due to compiler bug.

[kjellander_webrtc, 2015/06/18 09:06:23]

Please link to the bug etc, similar to my previous comment.

[Andrew MacDonald, 2015/06/25 01:09:09]

Done.

     if (rtc_use_lto) {
       cflags -= [
         "-flto",
         "-ffat-lto-objects",
       ]
     }
 
     configs += [ "../..:common_config" ]
     public_configs = [ "../..:common_inherited_config" ]
 
@@ skipping 157 matching lines @@
     "../../system_wrappers",
   ]
 
   defines = []
 
   if (rtc_include_opus) {
     defines += [ "WEBRTC_CODEC_OPUS" ]
     deps += [ ":webrtc_opus" ]
   }
 }