bugfix - set backtrack events according to an *enabled* thread
[model-checker.git] / model.cc
index f541d48d6114a25c5602fcadda7af1a4377df293..e3238258a3aa86b0570ff8ed8159eb62e27a899c 100644 (file)
--- a/model.cc
+++ b/model.cc
@@ -8,12 +8,33 @@
 
 #define INITIAL_THREAD_ID      0
 
+class Backtrack {
+public:
+       Backtrack(ModelAction *d, action_list_t *t) {
+               diverge = d;
+               actionTrace = t;
+               iter = actionTrace->begin();
+       }
+       ModelAction * get_diverge() { return diverge; }
+       action_list_t * get_trace() { return actionTrace; }
+       void advance_state() { iter++; }
+       ModelAction * get_state() {
+               return iter == actionTrace->end() ? NULL : *iter;
+       }
+private:
+       ModelAction *diverge;
+       action_list_t *actionTrace;
+       /* points to position in actionTrace as we replay */
+       action_list_t::iterator iter;
+};
+
 ModelChecker *model;
 
 ModelChecker::ModelChecker()
 {
-       /* First thread created will have id (INITIAL_THREAD_ID + 1) */
-       this->used_thread_id = INITIAL_THREAD_ID;
+       /* First thread created will have id INITIAL_THREAD_ID */
+       this->next_thread_id = INITIAL_THREAD_ID;
+       used_sequence_numbers = 0;
        /* Initialize default scheduler */
        this->scheduler = new Scheduler();
 
@@ -22,7 +43,7 @@ ModelChecker::ModelChecker()
        this->exploring = NULL;
        this->nextThread = THREAD_ID_T_NONE;
 
-       rootNode = new TreeNode(NULL);
+       rootNode = new TreeNode();
        currentNode = rootNode;
        action_trace = new action_list_t();
 }
@@ -37,20 +58,26 @@ ModelChecker::~ModelChecker()
 void ModelChecker::reset_to_initial_state()
 {
        DEBUG("+++ Resetting to initial state +++\n");
-       std::map<thread_id_t, class Thread *>::iterator it;
+       std::map<int, 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 = INITIAL_THREAD_ID;
+       next_thread_id = INITIAL_THREAD_ID;
+       used_sequence_numbers = 0;
        /* scheduler reset ? */
 }
 
 thread_id_t ModelChecker::get_next_id()
 {
-       return ++used_thread_id;
+       return next_thread_id++;
+}
+
+int ModelChecker::get_next_seq_num()
+{
+       return ++used_sequence_numbers;
 }
 
 Thread * ModelChecker::schedule_next_thread()
@@ -58,7 +85,7 @@ Thread * ModelChecker::schedule_next_thread()
        Thread *t;
        if (nextThread == THREAD_ID_T_NONE)
                return NULL;
-       t = thread_map[nextThread];
+       t = thread_map[id_to_int(nextThread)];
        if (t == NULL)
                DEBUG("*** error: thread not in thread_map: id = %d\n", nextThread);
        return t;
@@ -101,18 +128,27 @@ thread_id_t ModelChecker::advance_backtracking_state()
 
        /* Else, we are trying to replay an execution */
        exploring->advance_state();
-       if (exploring->get_state() == NULL)
-               DEBUG("*** error: reached end of backtrack trace\n");
+
+       ASSERT(exploring->get_state() != NULL);
 
        return get_next_replay_thread();
 }
 
 bool ModelChecker::next_execution()
 {
+       DBG();
+
        num_executions++;
        print_summary();
        if ((exploring = model->get_next_backtrack()) == NULL)
                return false;
+
+       if (DBG_ENABLED()) {
+               printf("Next execution will diverge at:\n");
+               exploring->get_diverge()->print();
+               print_list(exploring->get_trace());
+       }
+
        model->reset_to_initial_state();
        nextThread = get_next_replay_thread();
        return true;
@@ -146,6 +182,7 @@ void ModelChecker::set_backtracking(ModelAction *act)
 {
        ModelAction *prev;
        TreeNode *node;
+       Thread *t = get_thread(act->get_tid());
 
        prev = get_last_conflict(act);
        if (prev == NULL)
@@ -153,15 +190,18 @@ void ModelChecker::set_backtracking(ModelAction *act)
 
        node = prev->get_node();
 
+       while (t && !node->is_enabled(t))
+               t = t->get_parent();
+
        /* Check if this has been explored already */
-       if (node->hasBeenExplored(act->get_tid()))
+       if (node->hasBeenExplored(t->get_id()))
                return;
        /* If this is a new backtracking point, mark the tree */
-       if (node->setBacktrack(act->get_tid()) != 0)
+       if (node->setBacktrack(t->get_id()) != 0)
                return;
 
        DEBUG("Setting backtrack: conflict = %d, instead tid = %d\n",
-                       prev->get_tid(), act->get_tid());
+                       prev->get_tid(), t->get_id());
        if (DBG_ENABLED()) {
                prev->print();
                act->print();
@@ -193,25 +233,31 @@ void ModelChecker::check_current_action(void)
        nextThread = advance_backtracking_state();
        next->set_node(currentNode);
        set_backtracking(next);
-       currentNode = currentNode->exploreChild(next->get_tid());
+       currentNode = currentNode->explore_child(next);
        this->action_trace->push_back(next);
 }
 
 void ModelChecker::print_summary(void)
 {
-       action_list_t::iterator it;
-
        printf("\n");
-       printf("---------------------------------------------------------------------\n");
        printf("Number of executions: %d\n", num_executions);
-       printf("Total nodes created: %d\n\n", TreeNode::getTotalNodes());
+       printf("Total nodes created: %d\n", TreeNode::getTotalNodes());
 
        scheduler->print();
 
-       printf("Trace:\n\n");
+       print_list(action_trace);
+       printf("\n");
+
+}
+
+void ModelChecker::print_list(action_list_t *list)
+{
+       action_list_t::iterator it;
+
+       printf("---------------------------------------------------------------------\n");
+       printf("Trace:\n");
 
-       for (it = action_trace->begin(); it != action_trace->end(); it++) {
-               DBG();
+       for (it = list->begin(); it != list->end(); it++) {
                (*it)->print();
        }
        printf("---------------------------------------------------------------------\n");
@@ -219,7 +265,7 @@ void ModelChecker::print_summary(void)
 
 int ModelChecker::add_thread(Thread *t)
 {
-       thread_map[t->get_id()] = t;
+       thread_map[id_to_int(t->get_id())] = t;
        scheduler->add_thread(t);
        return 0;
 }
@@ -250,6 +296,7 @@ ModelAction::ModelAction(action_type_t type, memory_order order, void *loc, int
        act->location = loc;
        act->tid = t->get_id();
        act->value = value;
+       act->seq_number = model->get_next_seq_num();
 }
 
 bool ModelAction::is_read()
@@ -331,5 +378,6 @@ void ModelAction::print(void)
                type_str = "unknown type";
        }
 
-       printf("Thread: %d\tAction: %s\tMO: %d\tLoc: %#014zx\tValue: %d\n", id_to_int(tid), type_str, order, (size_t)location, value);
+       printf("(%4d) Thread: %d\tAction: %s\tMO: %d\tLoc: %14p\tValue: %d\n",
+                       seq_number, id_to_int(tid), type_str, order, location, value);
 }