1 files changed, 88 insertions, 0 deletions
diff --git a/deps/lightening/tests/z_atomic.c b/deps/lightening/tests/z_atomic.c
new file mode 100644
index 0000000..8612d15
--- /dev/null
+++ b/deps/lightening/tests/z_atomic.c
@@ -0,0 +1,88 @@
+#include "test.h"
+
+#include <threads.h>
+
+/* note non-atomic counter! */
+size_t num = 0;
+long lock_var = 0;
+void (*spin_lock)(void);
+void (*spin_unlock)(void);
+
+/* arbitrary number, as long as its large enough to likely allow other threads
+ * to spawn. */
+#define THREAD_INCREMENTS 1000000
+static int
+loop(void *arg)
+{
+  for (size_t i = 0; i < THREAD_INCREMENTS; ++i) {
+    (*spin_lock)();
+    num++;
+    (*spin_unlock)();
+  }
+
+  return 0;
+}
+
+#define NUM_THREADS 10
+static void
+run_loops()
+{
+  thrd_t threads[NUM_THREADS];
+  for (size_t i = 0; i < NUM_THREADS; ++i)
+    ASSERT(thrd_create(&threads[i], loop, NULL) == thrd_success);
+
+  for (size_t i = 0; i < NUM_THREADS; ++i)
+    ASSERT(thrd_join(threads[i], NULL) == thrd_success);
+
+  ASSERT(num == NUM_THREADS * THREAD_INCREMENTS);
+}
+
+static size_t
+run_test(jit_state_t *_jit, uint8_t *arena_base, size_t arena_size)
+{
+  jit_begin(_jit, arena_base, arena_size);
+
+  /* based on https://rigtorp.se/spinlock/ */
+  spin_lock = jit_address(_jit);
+  {
+    size_t frame = jit_enter_jit_abi(_jit, 0, 0, 0);
+    void *do_exchange = jit_address(_jit);
+    void *while_load = jit_address(_jit);
+    /* do { */
+    /* while (atomic_load(lock_var)); */
+    jit_movi(_jit, JIT_R1, (jit_imm_t)&lock_var);
+    jit_ldr_atomic(_jit, JIT_R0, JIT_R1);
+    jit_patch_there(_jit, jit_bnei(_jit, JIT_R0, 0), while_load);
+    /* } while (atomic_exchange(lock_var, 1)); */
+    jit_movi(_jit, JIT_R0, 1);
+    jit_swap_atomic(_jit, JIT_R0, JIT_R1, JIT_R0);
+    jit_patch_there(_jit, jit_bnei(_jit, JIT_R0, 0), do_exchange);
+    jit_leave_jit_abi(_jit, 0, 0, frame);
+    jit_ret(_jit);
+  }
+
+  spin_unlock = jit_address(_jit);
+  {
+    size_t frame = jit_enter_jit_abi(_jit, 0, 0, 0);
+    jit_movi(_jit, JIT_R0, 0);
+    jit_movi(_jit, JIT_R1, (jit_imm_t)&lock_var);
+    jit_str_atomic(_jit, JIT_R1, JIT_R0);
+    jit_leave_jit_abi(_jit, 0, 0, frame);
+    jit_ret(_jit);
+  }
+
+  size_t size;
+  void *p = jit_end(_jit, &size);
+
+  if (p)
+    run_loops();
+  else
+    return size;
+
+  return 0;
+}
+
+int main(int argc, char *argv[])
+{
+  return main_compiler(argc, argv, run_test);
+}