X-Git-Url: http://demsky.eecs.uci.edu/git/?a=blobdiff_plain;f=model.cc;h=94620ea9d0400fcee239973705361210542040f5;hb=6b87c110fbda87ccec4f58b1e292d5f9434c8691;hp=78907f1dab02648a327c86f1c0fbd3a72dd80c05;hpb=e019c4b58edb829582d6a5689240b9e8e8908f05;p=model-checker.git

diff --git a/model.cc b/model.cc
index 78907f1..94620ea 100644
--- a/model.cc
+++ b/model.cc
@@ -101,7 +101,7 @@ thread_id_t ModelChecker::get_next_id()
 }
 
 /** @return the number of user threads created during this execution */
-unsigned int ModelChecker::get_num_threads()
+unsigned int ModelChecker::get_num_threads() const
 {
 	return priv->next_thread_id;
 }
@@ -244,6 +244,26 @@ void ModelChecker::wake_up_sleeping_actions(ModelAction * curr) {
 	}
 }
 
+/**
+ * Check if we are in a deadlock. Should only be called at the end of an
+ * execution, although it should not give false positives in the middle of an
+ * execution (there should be some ENABLED thread).
+ *
+ * @return True if program is in a deadlock; false otherwise
+ */
+bool ModelChecker::is_deadlocked() const
+{
+	bool blocking_threads = false;
+	for (unsigned int i = 0; i < get_num_threads(); i++) {
+		Thread *t = get_thread(int_to_id(i));
+		if (scheduler->is_enabled(t) != THREAD_DISABLED)
+			return false;
+		else if (!t->is_model_thread() && t->get_pending())
+			blocking_threads = true;
+	}
+	return blocking_threads;
+}
+
 /**
  * Queries the model-checker for more executions to explore and, if one
  * exists, resets the model-checker state to execute a new execution.
@@ -257,6 +277,8 @@ bool ModelChecker::next_execution()
 
 	num_executions++;
 
+	if (is_deadlocked())
+		printf("ERROR: DEADLOCK\n");
 	if (isfinalfeasible()) {
 		printf("Earliest divergence point since last feasible execution:\n");
 		if (earliest_diverge)
@@ -2000,17 +2022,14 @@ void ModelChecker::build_reads_from_past(ModelAction *curr)
 
 			/* Don't consider more than one seq_cst write if we are a seq_cst read. */
 			if (!curr->is_seqcst() || (!act->is_seqcst() && (last_seq_cst == NULL || !act->happens_before(last_seq_cst))) || act == last_seq_cst) {
-				DEBUG("Adding action to may_read_from:\n");
-				if (DBG_ENABLED()) {
-					act->print();
-					curr->print();
-				}
-
-				if (curr->get_sleep_flag() && ! curr->is_seqcst()) {
-					if (sleep_can_read_from(curr, act))
-						curr->get_node()->add_read_from(act);
-				} else
+				if (!curr->get_sleep_flag() || curr->is_seqcst() || sleep_can_read_from(curr, act)) {
+					DEBUG("Adding action to may_read_from:\n");
+					if (DBG_ENABLED()) {
+						act->print();
+						curr->print();
+					}
 					curr->get_node()->add_read_from(act);
+				}
 			}
 
 			/* Include at most one act per-thread that "happens before" curr */