sha \
tree \
xtea \
+
+TESTPROGS-$(HAVE_THREADS) += cpu_init
*/
#include <stdint.h>
+#include <stdatomic.h>
#include "cpu.h"
#include "cpu_internal.h"
#include <unistd.h>
#endif
-static int cpuflags_mask = -1, checked;
+static atomic_int cpu_flags = ATOMIC_VAR_INIT(-1);
-int av_get_cpu_flags(void)
+static int get_cpu_flags(void)
{
- static int flags;
-
- if (checked)
- return flags;
-
if (ARCH_AARCH64)
- flags = ff_get_cpu_flags_aarch64();
+ return ff_get_cpu_flags_aarch64();
if (ARCH_ARM)
- flags = ff_get_cpu_flags_arm();
+ return ff_get_cpu_flags_arm();
if (ARCH_PPC)
- flags = ff_get_cpu_flags_ppc();
+ return ff_get_cpu_flags_ppc();
if (ARCH_X86)
- flags = ff_get_cpu_flags_x86();
-
- flags &= cpuflags_mask;
- checked = 1;
+ return ff_get_cpu_flags_x86();
+ return 0;
+}
+int av_get_cpu_flags(void)
+{
+ int flags = atomic_load_explicit(&cpu_flags, memory_order_relaxed);
+ if (flags == -1) {
+ flags = get_cpu_flags();
+ atomic_store_explicit(&cpu_flags, flags, memory_order_relaxed);
+ }
return flags;
}
void av_set_cpu_flags_mask(int mask)
{
- cpuflags_mask = mask;
- checked = 0;
+ atomic_store_explicit(&cpu_flags, get_cpu_flags() & mask,
+ memory_order_relaxed);
}
int av_parse_cpu_flags(const char *s)
/**
* Set a mask on flags returned by av_get_cpu_flags().
* This function is mainly useful for testing.
- *
- * @warning this function is not thread safe.
*/
void av_set_cpu_flags_mask(int mask);
/base64
/blowfish
/cpu
+/cpu_init
/crc
/des
/eval
--- /dev/null
+/*
+ * This file is part of Libav.
+ *
+ * Libav is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * Libav is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with Libav; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+/*
+ * This test program tests whether the one-time initialization in
+ * av_get_cpu_flags() has data races.
+ */
+
+#include <stdio.h>
+#include <string.h>
+
+#include "libavutil/cpu.h"
+#include "libavutil/thread.h"
+
+static void *thread_main(void *arg)
+{
+ int *flags = arg;
+
+ *flags = av_get_cpu_flags();
+ return NULL;
+}
+
+int main(void)
+{
+ int cpu_flags1;
+ int cpu_flags2;
+ int ret;
+ pthread_t thread1;
+ pthread_t thread2;
+
+ if ((ret = pthread_create(&thread1, NULL, thread_main, &cpu_flags1))) {
+ fprintf(stderr, "pthread_create failed: %s.\n", strerror(ret));
+ return 1;
+ }
+ if ((ret = pthread_create(&thread2, NULL, thread_main, &cpu_flags2))) {
+ fprintf(stderr, "pthread_create failed: %s.\n", strerror(ret));
+ return 1;
+ }
+ pthread_join(thread1, NULL);
+ pthread_join(thread2, NULL);
+
+ if (cpu_flags1 < 0)
+ return 2;
+ if (cpu_flags2 < 0)
+ return 2;
+ if (cpu_flags1 != cpu_flags2)
+ return 3;
+
+ return 0;
+}
fate-cpu: CMD = run libavutil/tests/cpu $(CPUFLAGS:%=-c%) $(THREADS:%=-t%)
fate-cpu: REF = /dev/null
+FATE_LIBAVUTIL-$(HAVE_THREADS) += fate-cpu_init
+fate-cpu_init: libavutil/tests/cpu_init$(EXESUF)
+fate-cpu_init: CMD = run libavutil/tests/cpu_init
+fate-cpu_init: REF = /dev/null
+
FATE_LIBAVUTIL += fate-crc
fate-crc: libavutil/tests/crc$(EXESUF)
fate-crc: CMD = run libavutil/tests/crc
fate-xtea: libavutil/tests/xtea$(EXESUF)
fate-xtea: CMD = run libavutil/tests/xtea
+FATE_LIBAVUTIL += $(FATE_LIBAVUTIL-yes)
FATE-$(CONFIG_AVUTIL) += $(FATE_LIBAVUTIL)
fate-libavutil: $(FATE_LIBAVUTIL)