/* Initialize default scheduler */
this->scheduler = new Scheduler();
+ num_executions = 0;
this->current_action = NULL;
+ this->exploring = NULL;
+ this->nextThread = THREAD_ID_T_NONE;
+
+ rootNode = new TreeNode(NULL);
+ currentNode = rootNode;
+ action_trace = new action_list_t();
}
ModelChecker::~ModelChecker()
{
+ delete action_trace;
delete this->scheduler;
+ delete rootNode;
+}
+
+void ModelChecker::reset_to_initial_state()
+{
+ DEBUG("+++ Resetting to initial state +++\n");
+ std::map<thread_id_t, class Thread *>::iterator it;
+ for (it = thread_map.begin(); it != thread_map.end(); it++) {
+ delete (*it).second;
+ }
+ thread_map.clear();
+ action_trace = new action_list_t();
+ currentNode = rootNode;
+ current_action = NULL;
+ used_thread_id = 1; // ?
+ /* scheduler reset ? */
}
-void ModelChecker::assign_id(Thread *t)
+int ModelChecker::get_next_id()
{
- t->set_id(++used_thread_id);
+ return ++used_thread_id;
}
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();
+}
+
+bool ModelChecker::next_execution()
+{
+ num_executions++;
+ print_summary();
+ if ((exploring = model->get_next_backtrack()) == NULL)
+ return false;
+ model->reset_to_initial_state();
+ nextThread = get_next_replay_thread();
+ return true;
+}
+
+ModelAction * ModelChecker::get_last_conflict(ModelAction *act)
+{
+ void *loc = act->get_location();
+ action_type type = act->get_type();
+ thread_id_t id = act->get_tid();
+
+ switch (type) {
+ case THREAD_CREATE:
+ case THREAD_YIELD:
+ case THREAD_JOIN:
+ return NULL;
+ case ATOMIC_READ:
+ case ATOMIC_WRITE:
+ 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;
+ if (prev->get_location() != loc)
+ continue;
+ if (type == ATOMIC_READ && prev->get_type() != ATOMIC_WRITE)
+ continue;
+ /* Conflict from the same thread is not really a conflict */
+ if (id == prev->get_tid())
+ return NULL;
+ return prev;
+ }
+ return NULL;
+}
+
+void ModelChecker::set_backtracking(ModelAction *act)
+{
+ ModelAction *prev;
+ TreeNode *node;
+
+ prev = get_last_conflict(act);
+ if (prev == NULL)
+ return;
+
+ node = prev->get_node();
+
+ /* Check if this has been explored already */
+ if (node->hasBeenExplored(act->get_tid()))
+ return;
+ /* If this is a new backtracking point, mark the tree */
+ if (node->setBacktrack(act->get_tid()) != 0)
+ return;
+
+ printf("Setting backtrack: conflict = %d, instead tid = %d\n",
+ prev->get_tid(), act->get_tid());
+ prev->print();
+ act->print();
+
+ Backtrack *back = new Backtrack(prev, action_trace);
+ backtrack_list.push_back(back);
+}
+
+Backtrack * ModelChecker::get_next_backtrack()
+{
+ Backtrack *next;
+ if (backtrack_list.empty())
+ return NULL;
+ next = backtrack_list.back();
+ backtrack_list.pop_back();
+ return next;
+}
+
void ModelChecker::check_current_action(void)
{
- if (this->current_action)
- this->action_trace.push_back(this->current_action);
- else
+ ModelAction *next = this->current_action;
+
+ if (!next) {
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());
+ this->action_trace->push_back(next);
}
-void ModelChecker::print_trace(void)
+void ModelChecker::print_summary(void)
{
- std::list<class ModelAction *>::iterator it;
+ action_list_t::iterator it;
- for (it = action_trace.begin(); it != action_trace.end(); it++) {
+ printf("\n");
+ printf("---------------------------------------------------------------------\n");
+ printf("Number of executions: %d\n", num_executions);
+ printf("Total nodes created: %d\n\n", TreeNode::getTotalNodes());
+
+ scheduler->print();
+
+ printf("Trace:\n\n");
+
+ for (it = action_trace->begin(); it != action_trace->end(); it++) {
DBG();
(*it)->print();
}
+ printf("---------------------------------------------------------------------\n");
}
int ModelChecker::add_thread(Thread *t)
{
thread_map[t->get_id()] = t;
+ scheduler->add_thread(t);
return 0;
}
+void ModelChecker::remove_thread(Thread *t)
+{
+ scheduler->remove_thread(t);
+}
+
int ModelChecker::switch_to_master(ModelAction *act)
{
Thread *old, *next;