X-Git-Url: http://demsky.eecs.uci.edu/git/?a=blobdiff_plain;f=model.cc;h=52eab24c6790fdc472bdfc30937fa356aa319fed;hb=547377c72c02a7831b63f5c7aa2ac2559109907c;hp=134e457eb44468e02c4d9879e89e1c25a1679c2a;hpb=7f9eb951a3ee0443169dd21ddc914df4a04c9aab;p=model-checker.git

diff --git a/model.cc b/model.cc
index 134e457..52eab24 100644
--- a/model.cc
+++ b/model.cc
@@ -441,7 +441,7 @@ ModelAction * ModelChecker::get_next_backtrack()
  */
 bool ModelChecker::process_read(ModelAction *curr, bool second_part_of_rmw)
 {
-	uint64_t value;
+	uint64_t value = VALUE_NONE;
 	bool updated = false;
 	while (true) {
 		const ModelAction *reads_from = curr->get_node()->get_read_from();
@@ -1366,32 +1366,40 @@ bool ModelChecker::thin_air_constraint_may_allow(const ModelAction * writer, con
 	return true;
 }
 
-/** Arbitrary reads from the future are not allowed.  Section 29.3
- * part 9 places some constraints.  This method checks one result of constraint
- * constraint.  Others require compiler support. */
-bool ModelChecker::mo_may_allow(const ModelAction * writer, const ModelAction *reader) {
+/**
+ * Arbitrary reads from the future are not allowed. Section 29.3 part 9 places
+ * some constraints. This method checks one the following constraint (others
+ * require compiler support):
+ *
+ *   If X --hb-> Y --mo-> Z, then X should not read from Z.
+ */
+bool ModelChecker::mo_may_allow(const ModelAction *writer, const ModelAction *reader)
+{
 	std::vector<action_list_t> *thrd_lists = obj_thrd_map->get_safe_ptr(reader->get_location());
+	unsigned int i;
 
-	//Get write that follows reader action
-	action_list_t *list = &(*thrd_lists)[id_to_int(reader->get_tid())];
-	action_list_t::reverse_iterator rit;
-	ModelAction *first_write_after_read=NULL;
-
-	for (rit = list->rbegin(); rit != list->rend(); rit++) {
-		ModelAction *act = *rit;
-		if (act==reader)
-			break;
-		if (act->is_write())
-			first_write_after_read=act;
-	}
+	/* Iterate over all threads */
+	for (i = 0; i < thrd_lists->size(); i++) {
+		ModelAction *write_after_read = NULL;
 
-	if (first_write_after_read==NULL)
-		return true;
+		/* Iterate over actions in thread, starting from most recent */
+		action_list_t *list = &(*thrd_lists)[i];
+		action_list_t::reverse_iterator rit;
+		for (rit = list->rbegin(); rit != list->rend(); rit++) {
+			ModelAction *act = *rit;
 
-	return !mo_graph->checkReachable(first_write_after_read, writer);
-}
+			if (!reader->happens_before(act))
+				break;
+			else if (act->is_write())
+				write_after_read = act;
+		}
 
+		if (write_after_read && mo_graph->checkReachable(write_after_read, writer))
+			return false;
+	}
 
+	return true;
+}
 
 /**
  * Finds the head(s) of the release sequence(s) containing a given ModelAction.
@@ -1815,6 +1823,7 @@ void ModelChecker::compute_promises(ModelAction *curr)
 				act->is_read() &&
 				!act->could_synchronize_with(curr) &&
 				!act->same_thread(curr) &&
+				act->get_location() == curr->get_location() &&
 				promise->get_value() == curr->get_value()) {
 			curr->get_node()->set_promise(i);
 		}
@@ -1993,6 +2002,7 @@ void ModelChecker::build_reads_from_past(ModelAction *curr)
 	if (!initialized) {
 		/** @todo Need a more informative way of reporting errors. */
 		printf("ERROR: may read from uninitialized atomic\n");
+		set_assert();
 	}
 
 	if (DBG_ENABLED() || !initialized) {
@@ -2002,8 +2012,6 @@ void ModelChecker::build_reads_from_past(ModelAction *curr)
 		curr->get_node()->print_may_read_from();
 		printf("End printing may_read_from\n");
 	}
-
-	ASSERT(initialized);
 }
 
 bool ModelChecker::sleep_can_read_from(ModelAction * curr, const ModelAction *write) {