Split targets mixing .c and .cc sources.

webrtc/common_audio/BUILD.gn

Index: webrtc/common_audio/BUILD.gn
diff --git a/webrtc/common_audio/BUILD.gn b/webrtc/common_audio/BUILD.gn
index a26d74b0ec4624a1c78e1b6fa3eb47ac86fe971d..39975e60ed93e40a872e8b5a769d2616a41554a7 100644
--- a/webrtc/common_audio/BUILD.gn
+++ b/webrtc/common_audio/BUILD.gn
@@ -28,8 +28,6 @@ rtc_static_library("common_audio") {
     "blocker.h",
     "channel_buffer.cc",
     "channel_buffer.h",
-    "fft4g.c",
-    "fft4g.h",
     "fir_filter.cc",
     "fir_filter.h",
     "fir_filter_neon.h",
@@ -49,6 +47,65 @@ rtc_static_library("common_audio") {
     "resampler/resampler.cc",
     "resampler/sinc_resampler.cc",
     "resampler/sinc_resampler.h",
+    "smoothing_filter.cc",
+    "smoothing_filter.h",
+    "sparse_fir_filter.cc",
+    "sparse_fir_filter.h",
+    "vad/include/vad.h",
+    "vad/vad.cc",
+    "wav_file.cc",
+    "wav_file.h",
+    "wav_header.cc",
+    "wav_header.h",
+    "window_generator.cc",
+    "window_generator.h",
+  ]
+
+  deps = [
+    "../base:rtc_analytics",
+    "../system_wrappers",
+  ]
+  public_deps = [
+    ":common_audio_c",
+  ]
+
+  defines = []
+  if (rtc_use_openmax_dl) {
+    sources += [
+      "real_fourier_openmax.cc",
+      "real_fourier_openmax.h",
+    ]
+    defines += [ "RTC_USE_OPENMAX_DL" ]
+    if (rtc_build_openmax_dl) {
+      deps += [ "//third_party/openmax_dl/dl" ]
+    }
+  }
+
+  if (rtc_build_with_neon) {
+    deps += [ ":common_audio_neon" ]
+  }
+
+  if (is_win) {
+    cflags = [ "/wd4334" ]  # Ignore warning on shift operator promotion.
+  }
+
+  public_configs = [ ":common_audio_config" ]
+
+  if (!build_with_chromium && is_clang) {
+    # Suppress warnings from the Chromium Clang plugin (bugs.webrtc.org/163).
+    suppressed_configs += [ "//build/config/clang:find_bad_constructs" ]
+  }
+
+  if (current_cpu == "x86" || current_cpu == "x64") {
+    deps += [ ":common_audio_sse2" ]
+  }
+}
+
+rtc_source_set("common_audio_c") {
+  visibility = [ ":*" ]  # Only targets in this file can depend on this.
+  sources = [
+    "fft4g.c",
+    "fft4g.h",
     "ring_buffer.c",
     "ring_buffer.h",
     "signal_processing/auto_corr_to_refl_coef.c",
@@ -86,13 +143,7 @@ rtc_static_library("common_audio") {
     "signal_processing/splitting_filter.c",
     "signal_processing/sqrt_of_one_minus_x_squared.c",
     "signal_processing/vector_scaling_operations.c",
-    "smoothing_filter.cc",
-    "smoothing_filter.h",
-    "sparse_fir_filter.cc",
-    "sparse_fir_filter.h",
-    "vad/include/vad.h",
     "vad/include/webrtc_vad.h",
-    "vad/vad.cc",
     "vad/vad_core.c",
     "vad/vad_core.h",
     "vad/vad_filterbank.c",
@@ -102,31 +153,8 @@ rtc_static_library("common_audio") {
     "vad/vad_sp.c",
     "vad/vad_sp.h",
     "vad/webrtc_vad.c",
-    "wav_file.cc",
-    "wav_file.h",
-    "wav_header.cc",
-    "wav_header.h",
-    "window_generator.cc",
-    "window_generator.h",
-  ]
-
-  deps = [
-    "../base:rtc_analytics",
-    "../system_wrappers",
   ]
 
-  defines = []
-  if (rtc_use_openmax_dl) {
-    sources += [
-      "real_fourier_openmax.cc",
-      "real_fourier_openmax.h",
-    ]
-    defines += [ "RTC_USE_OPENMAX_DL" ]
-    if (rtc_build_openmax_dl) {
-      deps += [ "//third_party/openmax_dl/dl" ]
-    }
-  }
-
   if (current_cpu == "arm") {
     sources += [
       "signal_processing/complex_bit_reverse_arm.S",
@@ -140,10 +168,6 @@ rtc_static_library("common_audio") {
     }
   }
 
-  if (rtc_build_with_neon) {
-    deps += [ ":common_audio_neon" ]
-  }
-
   if (current_cpu == "mipsel") {
     sources += [
       "signal_processing/complex_bit_reverse_mips.c",
@@ -176,15 +200,6 @@ rtc_static_library("common_audio") {
   }
 
   public_configs = [ ":common_audio_config" ]
-
-  if (!build_with_chromium && is_clang) {
-    # Suppress warnings from the Chromium Clang plugin (bugs.webrtc.org/163).
-    suppressed_configs += [ "//build/config/clang:find_bad_constructs" ]
-  }
-
-  if (current_cpu == "x86" || current_cpu == "x64") {
-    deps += [ ":common_audio_sse2" ]
-  }
 }
 
 if (current_cpu == "x86" || current_cpu == "x64") {
@@ -210,6 +225,38 @@ if (rtc_build_with_neon) {
     sources = [
       "fir_filter_neon.cc",
       "resampler/sinc_resampler_neon.cc",
+    ]
+
+    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.
+      suppressed_configs += [ "//build/config/compiler:compiler_arm_fpu" ]
+      cflags = [ "-mfpu=neon" ]
+    }
+
+    # Disable LTO on NEON targets due to compiler bug.
+    # TODO(fdegans): Enable this. See crbug.com/408997.
+    if (rtc_use_lto) {
+      cflags -= [
+        "-flto",
+        "-ffat-lto-objects",
+      ]
+    }
+
+    if (!build_with_chromium && is_clang) {
+      # Suppress warnings from the Chromium Clang plugin (bugs.webrtc.org/163).
+      suppressed_configs += [ "//build/config/clang:find_bad_constructs" ]
+    }
+
+    public_deps = [
+      ":common_audio_neon_c",
+    ]
+  }
+
+  rtc_source_set("common_audio_neon_c") {
+    visibility = [ ":*" ]  # Only targets in this file can depend on this.
+    sources = [
       "signal_processing/cross_correlation_neon.c",
       "signal_processing/downsample_fast_neon.c",
       "signal_processing/min_max_operations_neon.c",