Merge cpu_features build targets into //system_wrappers.

Before this CL, functions declared in cpu_features_wrapper.h where
not defined in the same build target, causing brittle builds that
might fail at link time if the binary was not depending on
//system_wrappers (the target with the definitions), violating [1].

This CL moves everything into //system_wrappers and also moves
cpu_features_wrapper.h definitions from C to C++ (in order to be able
to add the definitions to a C++ build target like //system_wrappers).

[1] - https://webrtc.googlesource.com/src/+/refs/heads/master/style-guide.md#h-cc-pairs

Bug: None
Change-Id: I5a0009cddb17206b19f2a71eeba722faacc4bcae
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/183380
Commit-Queue: Mirko Bonadei <mbonadei@webrtc.org>
Reviewed-by: Karl Wiberg <kwiberg@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#32039}

common_audio/BUILD.gn

@@ -54,7 +54,6 @@ rtc_library("common_audio") {
     "../rtc_base/system:arch",
     "../rtc_base/system:file_wrapper",
     "../system_wrappers",
-    "../system_wrappers:cpu_features_api",
     "third_party/ooura:fft_size_256",
   ]
   absl_deps = [ "//third_party/abseil-cpp/absl/types:optional" ]
@@ -185,7 +184,6 @@ rtc_library("common_audio_c") {
     "../rtc_base:sanitizer",
     "../rtc_base/system:arch",
     "../system_wrappers",
-    "../system_wrappers:cpu_features_api",
     "third_party/ooura:fft_size_256",
     "third_party/spl_sqrt_floor",
   ]
@@ -232,7 +230,7 @@ rtc_library("fir_filter_factory") {
     "../rtc_base:checks",
     "../rtc_base:rtc_base_approved",
     "../rtc_base/system:arch",
-    "../system_wrappers:cpu_features_api",
+    "../system_wrappers",
   ]
   if (current_cpu == "x86" || current_cpu == "x64") {
     deps += [ ":common_audio_sse2" ]
@@ -383,7 +381,7 @@ if (rtc_include_tests) {
       "../rtc_base:rtc_base_approved",
       "../rtc_base:rtc_base_tests_utils",
       "../rtc_base/system:arch",
-      "../system_wrappers:cpu_features_api",
+      "../system_wrappers",
       "../test:fileutils",
       "../test:rtc_expect_death",
       "../test:test_main",

common_audio/third_party/ooura/BUILD.gn

@@ -16,7 +16,7 @@ rtc_library("fft_size_128") {
   ]
   deps = [
     "../../../rtc_base/system:arch",
-    "../../../system_wrappers:cpu_features_api",
+    "../../../system_wrappers",
   ]
   cflags = []
 

modules/audio_coding/BUILD.gn

@@ -609,7 +609,7 @@ rtc_library("isac_fix_c") {
     "../../rtc_base:compile_assert_c",
     "../../rtc_base:rtc_base_approved",
     "../../rtc_base:sanitizer",
-    "../../system_wrappers:cpu_features_api",
+    "../../system_wrappers",
     "../third_party/fft",
   ]
 
@@ -2067,7 +2067,6 @@ if (rtc_include_tests) {
       "../../rtc_base/synchronization:mutex",
       "../../rtc_base/system:arch",
       "../../system_wrappers",
-      "../../system_wrappers:cpu_features_api",
       "../../test:audio_codec_mocks",
       "../../test:field_trial",
       "../../test:fileutils",

modules/audio_processing/BUILD.gn

@@ -189,7 +189,7 @@ rtc_library("audio_processing") {
     "../../rtc_base:sanitizer",
     "../../rtc_base/synchronization:mutex",
     "../../rtc_base/system:rtc_export",
-    "../../system_wrappers:cpu_features_api",
+    "../../system_wrappers",
     "../../system_wrappers:field_trial",
     "../../system_wrappers:metrics",
     "aec3",
@@ -375,7 +375,6 @@ if (rtc_include_tests) {
       "../../rtc_base/system:arch",
       "../../rtc_base/system:file_wrapper",
       "../../system_wrappers",
-      "../../system_wrappers:cpu_features_api",
       "../../test:fileutils",
       "../../test:rtc_expect_death",
       "../../test:test_support",

modules/audio_processing/aec3/BUILD.gn

@@ -142,7 +142,7 @@ rtc_library("aec3") {
     "../../../rtc_base:safe_minmax",
     "../../../rtc_base/experiments:field_trial_parser",
     "../../../rtc_base/system:arch",
-    "../../../system_wrappers:cpu_features_api",
+    "../../../system_wrappers",
     "../../../system_wrappers:field_trial",
     "../../../system_wrappers:metrics",
     "../utility:cascaded_biquad_filter",
@@ -308,7 +308,7 @@ if (rtc_include_tests) {
       "../../../rtc_base:rtc_base_approved",
       "../../../rtc_base:safe_minmax",
       "../../../rtc_base/system:arch",
-      "../../../system_wrappers:cpu_features_api",
+      "../../../system_wrappers",
       "../../../test:field_trial",
       "../../../test:test_support",
       "../utility:cascaded_biquad_filter",

modules/audio_processing/aecm/BUILD.gn

@@ -21,7 +21,7 @@ rtc_library("aecm_core") {
     "../../../rtc_base:checks",
     "../../../rtc_base:rtc_base_approved",
     "../../../rtc_base:sanitizer",
-    "../../../system_wrappers:cpu_features_api",
+    "../../../system_wrappers",
     "../utility:legacy_delay_estimator",
   ]
   cflags = []

modules/audio_processing/agc/BUILD.gn

@@ -78,7 +78,7 @@ rtc_library("legacy_agc") {
     "../../../common_audio/third_party/ooura:fft_size_256",
     "../../../rtc_base:checks",
     "../../../rtc_base:rtc_base_approved",
-    "../../../system_wrappers:cpu_features_api",
+    "../../../system_wrappers",
   ]
 
   if (rtc_build_with_neon) {

modules/audio_processing/agc2/BUILD.gn

@@ -153,7 +153,7 @@ rtc_library("noise_level_estimator") {
     "../../../common_audio/third_party/ooura:fft_size_128",
     "../../../rtc_base:checks",
     "../../../rtc_base:macromagic",
-    "../../../system_wrappers:cpu_features_api",
+    "../../../system_wrappers",
   ]
 
   configs += [ "..:apm_debug_dump" ]

modules/audio_processing/agc2/rnn_vad/BUILD.gn

@@ -48,7 +48,7 @@ rtc_library("rnn_vad") {
     "../../../../rtc_base:checks",
     "../../../../rtc_base:rtc_base_approved",
     "../../../../rtc_base/system:arch",
-    "../../../../system_wrappers:cpu_features_api",
+    "../../../../system_wrappers",
     "../../utility:pffft_wrapper",
     "//third_party/rnnoise:rnn_vad",
   ]
@@ -67,7 +67,7 @@ if (rtc_include_tests) {
       "../../../../api:scoped_refptr",
       "../../../../rtc_base:checks",
       "../../../../rtc_base/system:arch",
-      "../../../../system_wrappers:cpu_features_api",
+      "../../../../system_wrappers",
       "../../../../test:fileutils",
       "../../../../test:test_support",
     ]

modules/audio_processing/ns/BUILD.gn

@@ -60,7 +60,7 @@ rtc_static_library("ns") {
     "../../../rtc_base:rtc_base_approved",
     "../../../rtc_base:safe_minmax",
     "../../../rtc_base/system:arch",
-    "../../../system_wrappers:cpu_features_api",
+    "../../../system_wrappers",
     "../../../system_wrappers:field_trial",
     "../../../system_wrappers:metrics",
     "../utility:cascaded_biquad_filter",
@@ -87,7 +87,7 @@ if (rtc_include_tests) {
       "../../../rtc_base:rtc_base_approved",
       "../../../rtc_base:safe_minmax",
       "../../../rtc_base/system:arch",
-      "../../../system_wrappers:cpu_features_api",
+      "../../../system_wrappers",
       "../../../test:test_support",
       "../utility:cascaded_biquad_filter",
     ]

modules/desktop_capture/BUILD.gn

@@ -115,7 +115,7 @@ if (rtc_include_tests) {
       ":primitives",
       "../../rtc_base:checks",
       "../../rtc_base:rtc_base_approved",
-      "../../system_wrappers:cpu_features_api",
+      "../../system_wrappers",
       "../../test:test_support",
     ]
     if (rtc_desktop_capture_supported) {
@@ -486,7 +486,6 @@ rtc_library("desktop_capture_generic") {
     "../../rtc_base/system:arch",
     "../../rtc_base/system:rtc_export",
     "../../system_wrappers",
-    "../../system_wrappers:cpu_features_api",
     "../../system_wrappers:metrics",
   ]
   absl_deps = [

modules/video_processing/BUILD.gn

@@ -37,7 +37,7 @@ rtc_library("video_processing") {
     "../../rtc_base:checks",
     "../../rtc_base:rtc_base_approved",
     "../../rtc_base/system:arch",
-    "../../system_wrappers:cpu_features_api",
+    "../../system_wrappers",
     "//third_party/libyuv",
   ]
   if (build_video_processing_sse2) {

system_wrappers/BUILD.gn

@@ -16,6 +16,7 @@ rtc_library("system_wrappers") {
   visibility = [ "*" ]
   sources = [
     "include/clock.h",
+    "include/cpu_features_wrapper.h",
     "include/cpu_info.h",
     "include/ntp_time.h",
     "include/rtp_to_ntp_estimator.h",
@@ -30,7 +31,6 @@ rtc_library("system_wrappers") {
   defines = []
   libs = []
   deps = [
-    ":cpu_features_api",
     "../api:array_view",
     "../api/units:timestamp",
     "../modules:module_api_public",
@@ -50,7 +50,8 @@ rtc_library("system_wrappers") {
         "/nsprpub/pr/include",
       ]
     } else {
-      deps += [ ":cpu_features_android" ]
+      sources += [ "source/cpu_features_android.cc" ]
+      deps += [ "//third_party/android_sdk:cpu_features" ]
     }
 
     libs += [ "log" ]
@@ -58,7 +59,7 @@ rtc_library("system_wrappers") {
 
   if (is_linux) {
     if (!build_with_chromium) {
-      deps += [ ":cpu_features_linux" ]
+      sources += [ "source/cpu_features_linux.cc" ]
     }
 
     libs += [ "rt" ]
@@ -78,10 +79,6 @@ rtc_library("system_wrappers") {
   ]
 }
 
-rtc_source_set("cpu_features_api") {
-  sources = [ "include/cpu_features_wrapper.h" ]
-}
-
 rtc_library("field_trial") {
   visibility = [ "*" ]
   public = [ "include/field_trial.h" ]
@@ -111,24 +108,6 @@ rtc_library("metrics") {
   ]
 }
 
-if (is_android && !build_with_mozilla) {
-  rtc_library("cpu_features_android") {
-    sources = [ "source/cpu_features_android.c" ]
-
-    deps = [ "//third_party/android_sdk:cpu_features" ]
-  }
-}
-
-if (is_linux) {
-  rtc_library("cpu_features_linux") {
-    sources = [ "source/cpu_features_linux.c" ]
-    deps = [
-      ":cpu_features_api",
-      "../rtc_base/system:arch",
-    ]
-  }
-}
-
 if (rtc_include_tests) {
   rtc_test("system_wrappers_unittests") {
     testonly = true

system_wrappers/include/cpu_features_wrapper.h

@@ -13,10 +13,6 @@
 
 #include <stdint.h>
 
-#if defined(__cplusplus) || defined(c_plusplus)
-extern "C" {
-#endif
-
 // List of features in x86.
 typedef enum { kSSE2, kSSE3, kAVX2 } CPUFeature;
 
@@ -41,8 +37,4 @@ extern WebRtc_CPUInfo WebRtc_GetCPUInfoNoASM;
 // values in the above enum definition as a bitmask.
 extern uint64_t WebRtc_GetCPUFeaturesARM(void);
 
-#if defined(__cplusplus) || defined(c_plusplus)
-}  // extern "C"
-#endif
-
 #endif  // SYSTEM_WRAPPERS_INCLUDE_CPU_FEATURES_WRAPPER_H_

system_wrappers/source/cpu_features_linux.cc

@@ -8,9 +8,9 @@
  *  be found in the AUTHORS file in the root of the source tree.
  */
 
+#include <features.h>
 #include <stdlib.h>
 #include <string.h>
-#include <features.h>
 
 #ifdef __GLIBC_PREREQ
 #define WEBRTC_GLIBC_PREREQ(a, b) __GLIBC_PREREQ(a, b)
@@ -21,10 +21,10 @@
 #if WEBRTC_GLIBC_PREREQ(2, 16)
 #include <sys/auxv.h>
 #else
-#include <fcntl.h>
-#include <unistd.h>
 #include <errno.h>
+#include <fcntl.h>
 #include <link.h>
+#include <unistd.h>
 #endif
 
 #include "rtc_base/system/arch.h"
@@ -36,7 +36,7 @@
 uint64_t WebRtc_GetCPUFeaturesARM(void) {
   uint64_t result = 0;
   int architecture = 0;
-  unsigned long hwcap = 0;
+  uint64_t hwcap = 0;
   const char* platform = NULL;
 #if WEBRTC_GLIBC_PREREQ(2, 16)
   hwcap = getauxval(AT_HWCAP);