model: pull thread control logic out of take_step(), check_current...()

Much of the scheduling and main control loop should be handled closer to
the top-level run() method. This is a start toward putting these
decisions at the appropriate level, making things more clear. Of course,
it's not complete.

diff --git a/model.cc b/model.cc
index f385e560f085cc9af3aec101207f732a7a3ef8e3..37417d644a14d40c3f5f6fa51dc1e883ca3d437c 100644 (file)
--- a/model.cc
+++ b/model.cc
@@ -1489,15 +1489,6 @@ ModelAction * ModelChecker::check_current_action(ModelAction *curr)
 {
        ASSERT(curr);
        bool second_part_of_rmw = curr->is_rmwc() || curr->is_rmw();
-
-       if (!check_action_enabled(curr)) {
-               /* Make the execution look like we chose to run this action
-                * much later, when a lock/join can succeed */
-               get_thread(curr)->set_pending(curr);
-               scheduler->sleep(get_thread(curr));
-               return NULL;
-       }
-
        bool newly_explored = initialize_curr_action(&curr);
 
        DBG();
@@ -3077,32 +3068,23 @@ Thread * ModelChecker::take_step(ModelAction *curr)
        Thread *curr_thrd = get_thread(curr);
        ASSERT(curr_thrd->get_state() == THREAD_READY);
 
-       curr = check_current_action(curr);
-
-       /* Infeasible -> don't take any more steps */
-       if (is_infeasible())
-               return NULL;
-       else if (isfeasibleprefix() && have_bug_reports()) {
-               set_assert();
-               return NULL;
+       if (!check_action_enabled(curr)) {
+               /* Make the execution look like we chose to run this action
+                * much later, when a lock/join can succeed */
+               get_thread(curr)->set_pending(curr);
+               scheduler->sleep(curr_thrd);
+               curr = NULL;
+       } else {
+               curr = check_current_action(curr);
+               ASSERT(curr);
        }
 
-       if (params.bound != 0 && priv->used_sequence_numbers > params.bound)
-               return NULL;
-
        if (curr_thrd->is_blocked() || curr_thrd->is_complete())
                scheduler->remove_thread(curr_thrd);
 
-       Thread *next_thrd = NULL;
        if (curr)
-               next_thrd = action_select_next_thread(curr);
-       if (!next_thrd)
-               next_thrd = get_next_thread();
-
-       DEBUG("(%d, %d)\n", curr_thrd ? id_to_int(curr_thrd->get_id()) : -1,
-                       next_thrd ? id_to_int(next_thrd->get_id()) : -1);
-
-       return next_thrd;
+               return action_select_next_thread(curr);
+       return NULL;
 }
 
 /** Wrapper to run the user's main function, with appropriate arguments */
@@ -3111,6 +3093,21 @@ void user_main_wrapper(void *)
        user_main(model->params.argc, model->params.argv);
 }
 
+bool ModelChecker::should_terminate_execution()
+{
+       /* Infeasible -> don't take any more steps */
+       if (is_infeasible())
+               return true;
+       else if (isfeasibleprefix() && have_bug_reports()) {
+               set_assert();
+               return true;
+       }
+
+       if (params.bound != 0 && priv->used_sequence_numbers > params.bound)
+               return true;
+       return false;
+}
+
 /** @brief Run ModelChecker for the user program */
 void ModelChecker::run()
 {
@@ -3141,11 +3138,16 @@ void ModelChecker::run()
                        if (has_asserted())
                                break;
 
+                       if (!t)
+                               t = get_next_thread();
+                       if (!t || t->is_model_thread())
+                               break;
+
                        /* Consume the next action for a Thread */
                        ModelAction *curr = t->get_pending();
                        t->set_pending(NULL);
                        t = take_step(curr);
-               } while (t && !t->is_model_thread());
+               } while (!should_terminate_execution());
 
                /*
                 * Launch end-of-execution release sequence fixups only when

diff --git a/model.h b/model.h
index 12ec06c060a999e256dfb57ea0088c97a09f81c3..73272809873ca66b11de81916f75c288953e4826 100644 (file)
--- a/model.h
+++ b/model.h
@@ -171,6 +171,7 @@ private:
        bool check_action_enabled(ModelAction *curr);
 
        Thread * take_step(ModelAction *curr);
+       bool should_terminate_execution();
 
        template <typename T>
        bool check_recency(ModelAction *curr, const T *rf) const;