+ Thread *t;
+ if (nextThread == THREAD_ID_T_NONE)
+ return NULL;
+ t = thread_map[id_to_int(nextThread)];
+
+ ASSERT(t != NULL);
+
+ return t;
+}
+
+/*
+ * get_next_replay_thread() - Choose the next thread in the replay sequence
+ *
+ * If we've reached the 'diverge' point, then we pick a thread from the
+ * backtracking set.
+ * Otherwise, we simply return the next thread in the sequence.
+ */
+thread_id_t ModelChecker::get_next_replay_thread()
+{
+ ModelAction *next;
+ thread_id_t tid;
+
+ /* Have we completed exploring the preselected path? */
+ if (diverge == NULL)
+ return THREAD_ID_T_NONE;
+
+ /* Else, we are trying to replay an execution */
+ next = node_stack->get_next()->get_action();
+
+ if (next == diverge) {
+ Node *node = next->get_node();
+
+ /* Reached divergence point */
+ DEBUG("*** Divergence point ***\n");
+ tid = node->get_next_backtrack();
+ diverge = NULL;
+ } else {
+ tid = next->get_tid();
+ }
+ DEBUG("*** ModelChecker chose next thread = %d ***\n", tid);
+ return tid;
+}
+
+bool ModelChecker::next_execution()
+{
+ DBG();
+
+ num_executions++;
+ print_summary();
+ if ((diverge = model->get_next_backtrack()) == NULL)
+ return false;
+
+ if (DBG_ENABLED()) {
+ printf("Next execution will diverge at:\n");
+ diverge->print();
+ }
+
+ model->reset_to_initial_state();
+ return true;