X-Git-Url: http://demsky.eecs.uci.edu/git/?a=blobdiff_plain;f=model.cc;h=0122922d376ca03a742f03729585f3c48db7b09a;hb=ea4611c1fc3b580020afbc04d531e4bc10fcca9c;hp=cd703edf329ef3245b8bcded411c540b3ac3ab22;hpb=ff3ab0abac18649da161a495781c3925cbcd62a4;p=model-checker.git

diff --git a/model.cc b/model.cc
index cd703ed..0122922 100644
--- a/model.cc
+++ b/model.cc
@@ -822,6 +822,21 @@ void ModelChecker::set_backtracking(ModelAction *act)
 			if (unfair)
 				continue;
 		}
+
+		/* See if CHESS-like yield fairness allows */
+		if (model->params.yieldon) {
+			bool unfair = false;
+			for (int t = 0; t < node->get_num_threads(); t++) {
+				thread_id_t tother = int_to_id(t);
+				if (node->is_enabled(tother) && node->has_priority_over(tid, tother)) {
+					unfair = true;
+					break;
+				}
+			}
+			if (unfair)
+				continue;
+		}
+		
 		/* Cache the latest backtracking point */
 		set_latest_backtrack(prev);
 
@@ -1369,6 +1384,8 @@ bool ModelChecker::initialize_curr_action(ModelAction **curr)
 bool ModelChecker::read_from(ModelAction *act, const ModelAction *rf)
 {
 	ASSERT(rf);
+	ASSERT(rf->is_write());
+
 	act->set_read_from(rf);
 	if (act->is_acquire()) {
 		rel_heads_list_t release_heads;
@@ -1476,6 +1493,11 @@ ModelAction * ModelChecker::check_current_action(ModelAction *curr)
 
 	wake_up_sleeping_actions(curr);
 
+	/* Compute fairness information for CHESS yield algorithm */
+	if (model->params.yieldon) {
+		curr->get_node()->update_yield(scheduler);
+	}
+
 	/* Add the action to lists before any other model-checking tasks */
 	if (!second_part_of_rmw)
 		add_action_to_lists(curr);
@@ -2350,9 +2372,9 @@ void ModelChecker::add_action_to_lists(ModelAction *act)
 	int uninit_id = -1;
 	action_list_t *list = get_safe_ptr_action(obj_map, act->get_location());
 	if (list->empty() && act->is_atomic_var()) {
-		uninit = new_uninitialized_action(act->get_location());
+		uninit = get_uninitialized_action(act);
 		uninit_id = id_to_int(uninit->get_tid());
-		list->push_back(uninit);
+		list->push_front(uninit);
 	}
 	list->push_back(act);
 
@@ -2793,14 +2815,21 @@ bool ModelChecker::sleep_can_read_from(ModelAction *curr, const ModelAction *wri
 }
 
 /**
- * @brief Create a new action representing an uninitialized atomic
- * @param location The memory location of the atomic object
- * @return A pointer to a new ModelAction
+ * @brief Get an action representing an uninitialized atomic
+ *
+ * This function may create a new one or try to retrieve one from the NodeStack
+ *
+ * @param curr The current action, which prompts the creation of an UNINIT action
+ * @return A pointer to the UNINIT ModelAction
  */
-ModelAction * ModelChecker::new_uninitialized_action(void *location) const
+ModelAction * ModelChecker::get_uninitialized_action(const ModelAction *curr) const
 {
-	ModelAction *act = (ModelAction *)snapshot_malloc(sizeof(class ModelAction));
-	act = new (act) ModelAction(ATOMIC_UNINIT, std::memory_order_relaxed, location, 0, model_thread);
+	Node *node = curr->get_node();
+	ModelAction *act = node->get_uninit_action();
+	if (!act) {
+		act = new ModelAction(ATOMIC_UNINIT, std::memory_order_relaxed, curr->get_location(), model->params.uninitvalue, model_thread);
+		node->set_uninit_action(act);
+	}
 	act->create_cv(NULL);
 	return act;
 }