void model_fence_action(memory_order ord);
uint64_t model_rmwr_action_helper(void *obj, int atomic_index, const char *position);
+uint64_t model_rmwrcas_action_helper(void *obj, int atomic_index, const char *position);
void model_rmw_action_helper(void *obj, uint64_t val, int atomic_index, const char *position);
void model_rmwc_action_helper(void *obj, int atomic_index, const char *position);
// void model_fence_action_helper(int atomic_index);