Implement CPU feature detection for ARM Linux.
BUG=webrtc:5057
NOTRY=True
Review URL: https://codereview.webrtc.org/1820133002
Cr-Commit-Position: refs/heads/master@{#12270}
diff --git a/webrtc/system_wrappers/BUILD.gn b/webrtc/system_wrappers/BUILD.gn
index bbad2d9..aff29de 100644
--- a/webrtc/system_wrappers/BUILD.gn
+++ b/webrtc/system_wrappers/BUILD.gn
@@ -107,6 +107,10 @@
if (is_linux) {
defines += [ "WEBRTC_THREAD_RR" ]
+ if (!build_with_chromium) {
+ deps += [ ":cpu_features_linux" ]
+ }
+
libs += [ "rt" ]
}
@@ -177,3 +181,14 @@
]
}
}
+
+if (is_linux) {
+ source_set("cpu_features_linux") {
+ sources = [
+ "source/cpu_features_linux.c",
+ ]
+
+ configs += [ "..:common_config" ]
+ public_configs = [ "..:common_inherited_config" ]
+ }
+}
diff --git a/webrtc/system_wrappers/cpu_features_webrtc.gyp b/webrtc/system_wrappers/cpu_features_webrtc.gyp
index 064b3cf..310e3b2 100644
--- a/webrtc/system_wrappers/cpu_features_webrtc.gyp
+++ b/webrtc/system_wrappers/cpu_features_webrtc.gyp
@@ -7,6 +7,7 @@
# be found in the AUTHORS file in the root of the source tree.
{
+ 'includes': [ '../build/common.gypi', ],
'conditions': [
['OS=="android"', {
'targets': [
@@ -22,5 +23,19 @@
},
],
}],
+ ['OS=="linux"', {
+ 'targets': [
+ {
+ 'target_name': 'cpu_features_linux',
+ 'type': 'static_library',
+ 'sources': [
+ 'source/cpu_features_linux.c',
+ ],
+ 'dependencies': [
+ '<(webrtc_root)/common.gyp:webrtc_common',
+ ],
+ },
+ ],
+ }],
], # conditions
}
diff --git a/webrtc/system_wrappers/source/cpu_features_linux.c b/webrtc/system_wrappers/source/cpu_features_linux.c
new file mode 100644
index 0000000..f23d827
--- /dev/null
+++ b/webrtc/system_wrappers/source/cpu_features_linux.c
@@ -0,0 +1,83 @@
+/*
+ * Copyright (c) 2016 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.
+ */
+
+#include <stdlib.h>
+#include <string.h>
+#include <features.h>
+#if __GLIBC_PREREQ(2, 16)
+#include <sys/auxv.h>
+#else
+#include <fcntl.h>
+#include <unistd.h>
+#include <errno.h>
+#include <link.h>
+#endif
+#include "webrtc/system_wrappers/include/cpu_features_wrapper.h"
+
+#if defined(WEBRTC_ARCH_ARM_FAMILY)
+#include <asm/hwcap.h>
+
+uint64_t WebRtc_GetCPUFeaturesARM(void) {
+ uint64_t result = 0;
+ int architecture = 0;
+ unsigned long hwcap = 0;
+ const char* platform = NULL;
+#if __GLIBC_PREREQ(2, 16)
+ hwcap = getauxval(AT_HWCAP);
+ platform = (const char*)getauxval(AT_PLATFORM);
+#else
+ ElfW(auxv_t) auxv;
+ int fd = open("/proc/self/auxv", O_RDONLY);
+ if (fd >= 0) {
+ while (hwcap == 0 || platform == NULL) {
+ if (read(fd, &auxv, sizeof(auxv)) < (ssize_t)sizeof(auxv)) {
+ if (errno == EINTR)
+ continue;
+ break;
+ }
+ switch (auxv.a_type) {
+ case AT_HWCAP:
+ hwcap = auxv.a_un.a_val;
+ break;
+ case AT_PLATFORM:
+ platform = (const char*)auxv.a_un.a_val;
+ break;
+ }
+ }
+ close(fd);
+ }
+#endif // __GLIBC_PREREQ(2,16)
+#if defined(__aarch64__)
+ architecture = 8;
+ if ((hwcap & HWCAP_FP) != 0)
+ result |= kCPUFeatureVFPv3;
+ if ((hwcap & HWCAP_ASIMD) != 0)
+ result |= kCPUFeatureNEON;
+#else
+ if (platform != NULL) {
+ /* expect a string in the form "v6l" or "v7l", etc.
+ */
+ if (platform[0] == 'v' && '0' <= platform[1] && platform[1] <= '9' &&
+ (platform[2] == 'l' || platform[2] == 'b')) {
+ architecture = platform[1] - '0';
+ }
+ }
+ if ((hwcap & HWCAP_VFPv3) != 0)
+ result |= kCPUFeatureVFPv3;
+ if ((hwcap & HWCAP_NEON) != 0)
+ result |= kCPUFeatureNEON;
+#endif
+ if (architecture >= 7)
+ result |= kCPUFeatureARMv7;
+ if (architecture >= 6)
+ result |= kCPUFeatureLDREXSTREX;
+ return result;
+}
+#endif // WEBRTC_ARCH_ARM_FAMILY
diff --git a/webrtc/system_wrappers/system_wrappers.gyp b/webrtc/system_wrappers/system_wrappers.gyp
index a8dc0c8..cd6d3ea 100644
--- a/webrtc/system_wrappers/system_wrappers.gyp
+++ b/webrtc/system_wrappers/system_wrappers.gyp
@@ -122,6 +122,13 @@
'defines': [
'WEBRTC_THREAD_RR',
],
+ 'conditions': [
+ ['build_with_chromium==0', {
+ 'dependencies': [
+ 'cpu_features_webrtc.gyp:cpu_features_linux',
+ ],
+ }],
+ ],
'link_settings': {
'libraries': [ '-lrt', ],
},
