model: bugfix - sleep sets are NOT directly compatible with DPOR
[model-checker.git] / model.cc
index 4d6e8af72b388dedf2502b13d732b9d801365a94..e6df37f8372949f610057599181402ddf673ce84 100644 (file)
--- a/model.cc
+++ b/model.cc
@@ -159,7 +159,7 @@ void ModelChecker::reset_to_initial_state()
        /* Print all model-checker output before rollback */
        fflush(model_out);
 
-       snapshotObject->backTrackBeforeStep(0);
+       snapshot_backtrack_before(0);
 }
 
 /** @return a thread ID for a new Thread */
@@ -174,7 +174,12 @@ unsigned int ModelChecker::get_num_threads() const
        return priv->next_thread_id;
 }
 
-/** @return The currently executing Thread. */
+/**
+ * Must be called from user-thread context (e.g., through the global
+ * thread_current() interface)
+ *
+ * @return The currently executing Thread.
+ */
 Thread * ModelChecker::get_current_thread() const
 {
        return scheduler->get_current_thread();
@@ -212,9 +217,8 @@ Thread * ModelChecker::get_next_thread(ModelAction *curr)
                /* Do not split atomic actions. */
                if (curr->is_rmwr())
                        return thread_current();
-               /* The THREAD_CREATE action points to the created Thread */
                else if (curr->get_type() == THREAD_CREATE)
-                       return (Thread *)curr->get_location();
+                       return curr->get_thread_operand();
        }
 
        /* Have we completed exploring the preselected path? */
@@ -254,6 +258,7 @@ Thread * ModelChecker::get_next_thread(ModelAction *curr)
                        tid = next->get_tid();
                        node_stack->pop_restofstack(2);
                } else {
+                       ASSERT(prevnode);
                        /* Make a different thread execute for next step */
                        scheduler->add_sleep(get_thread(next->get_tid()));
                        tid = prevnode->get_next_backtrack();
@@ -609,7 +614,7 @@ void ModelChecker::set_backtracking(ModelAction *act)
        Node *node = prev->get_node()->get_parent();
 
        int low_tid, high_tid;
-       if (node->is_enabled(t)) {
+       if (node->enabled_status(t->get_id()) == THREAD_ENABLED) {
                low_tid = id_to_int(act->get_tid());
                high_tid = low_tid + 1;
        } else {
@@ -819,7 +824,7 @@ bool ModelChecker::process_mutex(ModelAction *curr)
                if (curr->get_node()->get_misc() == 0) {
                        get_safe_ptr_action(condvar_waiters_map, curr->get_location())->push_back(curr);
                        //disable us
-                       scheduler->sleep(get_current_thread());
+                       scheduler->sleep(get_thread(curr));
                }
                break;
        }
@@ -848,6 +853,15 @@ bool ModelChecker::process_mutex(ModelAction *curr)
        return false;
 }
 
+void ModelChecker::add_future_value(const ModelAction *writer, ModelAction *reader)
+{
+       /* Do more ambitious checks now that mo is more complete */
+       if (mo_may_allow(writer, reader) &&
+                       reader->get_node()->add_future_value(writer->get_value(),
+                               writer->get_seq_number() + params.maxfuturedelay))
+               set_latest_backtrack(reader);
+}
+
 /**
  * Process a write ModelAction
  * @param curr The ModelAction to process
@@ -861,12 +875,9 @@ bool ModelChecker::process_write(ModelAction *curr)
        if (promises->size() == 0) {
                for (unsigned int i = 0; i < futurevalues->size(); i++) {
                        struct PendingFutureValue pfv = (*futurevalues)[i];
-                       //Do more ambitious checks now that mo is more complete
-                       if (mo_may_allow(pfv.writer, pfv.act) &&
-                                       pfv.act->get_node()->add_future_value(pfv.writer->get_value(), pfv.writer->get_seq_number() + params.maxfuturedelay))
-                               set_latest_backtrack(pfv.act);
+                       add_future_value(pfv.writer, pfv.act);
                }
-               futurevalues->resize(0);
+               futurevalues->clear();
        }
 
        mo_graph->commitChanges();
@@ -943,12 +954,12 @@ bool ModelChecker::process_thread_action(ModelAction *curr)
 
        switch (curr->get_type()) {
        case THREAD_CREATE: {
-               Thread *th = (Thread *)curr->get_location();
+               Thread *th = curr->get_thread_operand();
                th->set_creation(curr);
                break;
        }
        case THREAD_JOIN: {
-               Thread *blocking = (Thread *)curr->get_location();
+               Thread *blocking = curr->get_thread_operand();
                ModelAction *act = get_last_action(blocking->get_id());
                curr->synchronize_with(act);
                updated = true; /* trigger rel-seq checks */
@@ -1191,11 +1202,10 @@ void ModelChecker::set_current_action(ModelAction *act) {
  * execution when running permutations of previously-observed executions.
  *
  * @param curr The current action to process
- * @return The next Thread that must be executed. May be NULL if ModelChecker
- * makes no choice (e.g., according to replay execution, combining RMW actions,
- * etc.)
+ * @return The ModelAction that is actually executed; may be different than
+ * curr; may be NULL, if the current action is not enabled to run
  */
-Thread * ModelChecker::check_current_action(ModelAction *curr)
+ModelAction * ModelChecker::check_current_action(ModelAction *curr)
 {
        ASSERT(curr);
        bool second_part_of_rmw = curr->is_rmwc() || curr->is_rmw();
@@ -1203,13 +1213,17 @@ Thread * ModelChecker::check_current_action(ModelAction *curr)
        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_current_thread()->set_pending(curr);
-               scheduler->sleep(get_current_thread());
-               return get_next_thread(NULL);
+               get_thread(curr)->set_pending(curr);
+               scheduler->sleep(get_thread(curr));
+               return NULL;
        }
 
        bool newly_explored = initialize_curr_action(&curr);
 
+       DBG();
+       if (DBG_ENABLED())
+               curr->print();
+
        wake_up_sleeping_actions(curr);
 
        /* Add the action to lists before any other model-checking tasks */
@@ -1287,7 +1301,7 @@ Thread * ModelChecker::check_current_action(ModelAction *curr)
 
        check_curr_backtracking(curr);
        set_backtracking(curr);
-       return get_next_thread(curr);
+       return curr;
 }
 
 void ModelChecker::check_curr_backtracking(ModelAction *curr)
@@ -1295,7 +1309,7 @@ void ModelChecker::check_curr_backtracking(ModelAction *curr)
        Node *currnode = curr->get_node();
        Node *parnode = currnode->get_parent();
 
-       if (!parnode->backtrack_empty() ||
+       if ((parnode && !parnode->backtrack_empty()) ||
                         !currnode->misc_empty() ||
                         !currnode->read_from_empty() ||
                         !currnode->future_value_empty() ||
@@ -1325,15 +1339,39 @@ bool ModelChecker::isfeasibleprefix() const
        return pending_rel_seqs->size() == 0 && is_feasible_prefix_ignore_relseq();
 }
 
+/**
+ * Print disagnostic information about an infeasible execution
+ * @param prefix A string to prefix the output with; if NULL, then a default
+ * message prefix will be provided
+ */
+void ModelChecker::print_infeasibility(const char *prefix) const
+{
+       char buf[100];
+       char *ptr = buf;
+       if (mo_graph->checkForRMWViolation())
+               ptr += sprintf(ptr, "[RMW atomicity]");
+       if (mo_graph->checkForCycles())
+               ptr += sprintf(ptr, "[mo cycle]");
+       if (priv->failed_promise)
+               ptr += sprintf(ptr, "[failed promise]");
+       if (priv->too_many_reads)
+               ptr += sprintf(ptr, "[too many reads]");
+       if (priv->bad_synchronization)
+               ptr += sprintf(ptr, "[bad sw ordering]");
+       if (promises_expired())
+               ptr += sprintf(ptr, "[promise expired]");
+       if (promises->size() != 0)
+               ptr += sprintf(ptr, "[unresolved promise]");
+       if (ptr != buf)
+               model_print("%s: %s\n", prefix ? prefix : "Infeasible", buf);
+}
+
 /**
  * Returns whether the current completed trace is feasible, except for pending
  * release sequences.
  */
 bool ModelChecker::is_feasible_prefix_ignore_relseq() const
 {
-       if (DBG_ENABLED() && promises->size() != 0)
-               DEBUG("Infeasible: unrevolved promises\n");
-
        return !is_infeasible() && promises->size() == 0;
 }
 
@@ -1345,9 +1383,6 @@ bool ModelChecker::is_feasible_prefix_ignore_relseq() const
  */
 bool ModelChecker::is_infeasible() const
 {
-       if (DBG_ENABLED() && mo_graph->checkForRMWViolation())
-               DEBUG("Infeasible: RMW violation\n");
-
        return mo_graph->checkForRMWViolation() || is_infeasible_ignoreRMW();
 }
 
@@ -1361,18 +1396,6 @@ bool ModelChecker::is_infeasible() const
  * */
 bool ModelChecker::is_infeasible_ignoreRMW() const
 {
-       if (DBG_ENABLED()) {
-               if (mo_graph->checkForCycles())
-                       DEBUG("Infeasible: modification order cycles\n");
-               if (priv->failed_promise)
-                       DEBUG("Infeasible: failed promise\n");
-               if (priv->too_many_reads)
-                       DEBUG("Infeasible: too many reads\n");
-               if (priv->bad_synchronization)
-                       DEBUG("Infeasible: bad synchronization ordering\n");
-               if (promises_expired())
-                       DEBUG("Infeasible: promises expired\n");
-       }
        return mo_graph->checkForCycles() || priv->failed_promise ||
                priv->too_many_reads || priv->bad_synchronization ||
                promises_expired();
@@ -1765,8 +1788,7 @@ bool ModelChecker::w_modification_order(ModelAction *curr)
                                if (thin_air_constraint_may_allow(curr, act)) {
                                        if (!is_infeasible() ||
                                                        (curr->is_rmw() && act->is_rmw() && curr->get_reads_from() == act->get_reads_from() && !is_infeasible_ignoreRMW())) {
-                                               struct PendingFutureValue pfv = {curr, act};
-                                               futurevalues->push_back(pfv);
+                                               futurevalues->push_back(PendingFutureValue(curr, act));
                                        }
                                }
                        }
@@ -2503,14 +2525,8 @@ void ModelChecker::build_reads_from_past(ModelAction *curr)
                        else if (curr->get_sleep_flag() && !curr->is_seqcst() && !sleep_can_read_from(curr, act))
                                allow_read = false;
 
-                       if (allow_read) {
-                               DEBUG("Adding action to may_read_from:\n");
-                               if (DBG_ENABLED()) {
-                                       act->print();
-                                       curr->print();
-                               }
+                       if (allow_read)
                                curr->get_node()->add_read_from(act);
-                       }
 
                        /* Include at most one act per-thread that "happens before" curr */
                        if (act->happens_before(curr))
@@ -2560,13 +2576,11 @@ ModelAction * ModelChecker::new_uninitialized_action(void *location) const
        return act;
 }
 
-static void print_list(action_list_t *list, int exec_num = -1)
+static void print_list(action_list_t *list)
 {
        action_list_t::iterator it;
 
        model_print("---------------------------------------------------------------------\n");
-       if (exec_num >= 0)
-               model_print("Execution %d:\n", exec_num);
 
        unsigned int hash = 0;
 
@@ -2619,9 +2633,12 @@ void ModelChecker::print_summary() const
        dumpGraph(buffername);
 #endif
 
-       if (!isfeasibleprefix())
-               model_print("INFEASIBLE EXECUTION!\n");
-       print_list(action_trace, stats.num_total);
+       model_print("Execution %d:", stats.num_total);
+       if (isfeasibleprefix())
+               model_print("\n");
+       else
+               print_infeasibility(" INFEASIBLE");
+       print_list(action_trace);
        model_print("\n");
 }
 
@@ -2722,12 +2739,7 @@ bool ModelChecker::take_step(ModelAction *curr)
        Thread *curr_thrd = get_thread(curr);
        ASSERT(curr_thrd->get_state() == THREAD_READY);
 
-       Thread *next_thrd = check_current_action(curr);
-
-       if (curr_thrd->is_blocked() || curr_thrd->is_complete())
-               scheduler->remove_thread(curr_thrd);
-
-       next_thrd = scheduler->next_thread(next_thrd);
+       curr = check_current_action(curr);
 
        /* Infeasible -> don't take any more steps */
        if (is_infeasible())
@@ -2737,11 +2749,15 @@ bool ModelChecker::take_step(ModelAction *curr)
                return false;
        }
 
-       if (params.bound != 0) {
-               if (priv->used_sequence_numbers > params.bound) {
+       if (params.bound != 0)
+               if (priv->used_sequence_numbers > params.bound)
                        return false;
-               }
-       }
+
+       if (curr_thrd->is_blocked() || curr_thrd->is_complete())
+               scheduler->remove_thread(curr_thrd);
+
+       Thread *next_thrd = get_next_thread(curr);
+       next_thrd = scheduler->next_thread(next_thrd);
 
        DEBUG("(%d, %d)\n", curr_thrd ? id_to_int(curr_thrd->get_id()) : -1,
                        next_thrd ? id_to_int(next_thrd->get_id()) : -1);