schedule: bugfix - set 'current' thread in all cases

[model-checker.git] / model.cc

diff --git a/model.cc b/model.cc
index e496abd012a537b13019c292741a8dda6bc71935..bf956804479f3f1e82fe8f04fb273d50ce7c9cbb 100644 (file)
--- a/model.cc
+++ b/model.cc
@@ -14,6 +14,8 @@ ModelChecker::ModelChecker()
        this->scheduler = new Scheduler();
 
        this->current_action = NULL;
+       this->exploring = NULL;
+       this->nextThread = THREAD_ID_T_NONE;
 
        rootNode = new TreeNode(NULL);
        currentNode = rootNode;
@@ -37,6 +39,60 @@ void ModelChecker::add_system_thread(Thread *t)
        this->system_thread = t;
 }
 
+Thread *ModelChecker::schedule_next_thread()
+{
+       Thread *t;
+       if (nextThread == THREAD_ID_T_NONE)
+               return NULL;
+       t = thread_map[nextThread];
+       if (t == NULL)
+               DEBUG("*** error: thread not in thread_map: id = %d\n", nextThread);
+       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;
+
+       next = exploring->get_state();
+
+       if (next == exploring->get_diverge()) {
+               TreeNode *node = next->get_node();
+
+               /* Reached divergence point; discard our current 'exploring' */
+               DEBUG("*** Discard 'Backtrack' object ***\n");
+               tid = node->getNextBacktrack();
+               delete exploring;
+               exploring = NULL;
+       } else {
+               tid = next->get_tid();
+       }
+       DEBUG("*** ModelChecker chose next thread = %d ***\n", tid);
+       return tid;
+}
+
+thread_id_t ModelChecker::advance_backtracking_state()
+{
+       /* Have we completed exploring the preselected path? */
+       if (exploring == NULL)
+               return THREAD_ID_T_NONE;
+
+       /* Else, we are trying to replay an execution */
+       exploring->advance_state();
+       if (exploring->get_state() == NULL)
+               DEBUG("*** error: reached end of backtrack trace\n");
+
+       return get_next_replay_thread();
+}
+
 ModelAction *ModelChecker::get_last_conflict(ModelAction *act)
 {
        void *loc = act->get_location();
@@ -53,6 +109,7 @@ ModelAction *ModelChecker::get_last_conflict(ModelAction *act)
                default:
                        break;
        }
+       /* linear search: from most recent to oldest */
        action_list_t::reverse_iterator rit;
        for (rit = action_trace->rbegin(); rit != action_trace->rend(); rit++) {
                ModelAction *prev = *rit;
@@ -91,9 +148,8 @@ void ModelChecker::set_backtracking(ModelAction *act)
        prev->print();
        act->print();
 
-       /* FIXME */
-       //Backtrack *back = new Backtrack(prev, actionList);
-       //backtrackList->Append(back);
+       Backtrack *back = new Backtrack(prev, action_trace);
+       backtrack_list.push_back(back);
 }
 
 void ModelChecker::check_current_action(void)
@@ -104,6 +160,7 @@ void ModelChecker::check_current_action(void)
                DEBUG("trying to push NULL action...\n");
                return;
        }
+       nextThread = advance_backtracking_state();
        next->set_node(currentNode);
        set_backtracking(next);
        currentNode = currentNode->exploreChild(next->get_tid());