tests: add releaseseq test

Very simple release/acquire test, with some relaxed writes thrown in. The test
is semi-useful and can certainly be tweaked a bit.

diff --git a/test/releaseseq.c b/test/releaseseq.c
new file mode 100644 (file)
index 0000000..d3127f3
--- /dev/null
+++ b/test/releaseseq.c
@@ -0,0 +1,47 @@
+/*
+ * This test performs some relaxes, release, acquire opeations on a single
+ * atomic variable. It can give some rough idea of release sequence support but
+ * probably should be improved to give better information.
+ */
+
+#include <stdio.h>
+
+#include "libthreads.h"
+#include "librace.h"
+#include "stdatomic.h"
+
+atomic_int x;
+
+static void a(void *obj)
+{
+       atomic_store_explicit(&x, 1, memory_order_release);
+       atomic_store_explicit(&x, 42, memory_order_relaxed);
+}
+
+static void b(void *obj)
+{
+       int r = atomic_load_explicit(&x, memory_order_acquire);
+       printf("r = %u\n", r);
+}
+
+static void c(void *obj)
+{
+       atomic_store_explicit(&x, 2, memory_order_relaxed);
+}
+
+void user_main()
+{
+       thrd_t t1, t2, t3;
+
+       atomic_init(&x, 0);
+
+       printf("Thread %d: creating 3 threads\n", thrd_current());
+       thrd_create(&t1, (thrd_start_t)&a, NULL);
+       thrd_create(&t2, (thrd_start_t)&b, NULL);
+       thrd_create(&t3, (thrd_start_t)&c, NULL);
+
+       thrd_join(t1);
+       thrd_join(t2);
+       thrd_join(t3);
+       printf("Thread %d is finished\n", thrd_current());
+}