X-Git-Url: http://plrg.eecs.uci.edu/git/?p=model-checker.git;a=blobdiff_plain;f=nodestack.cc;h=409c4e1e52ba431b729ec4b1c6d95168cfbc675b;hp=10f7a72b5ef3ff5705fdbe29771def18212ecf11;hb=1dbc6ce8102e79ead8c3ae09214126abab1b5c51;hpb=fb2ab76b04c83faa654c8819c8e39b1e5fcc7d75

diff --git a/nodestack.cc b/nodestack.cc
index 10f7a72..409c4e1 100644
--- a/nodestack.cc
+++ b/nodestack.cc
@@ -24,7 +24,8 @@ Node::Node(ModelAction *act, Node *par, int nthreads)
 	explored_children(num_threads),
 	backtrack(num_threads),
 	numBacktracks(0),
-	may_read_from()
+	may_read_from(),
+	read_from_index(0)
 {
 	if (act)
 		act->set_node(this);
@@ -73,7 +74,16 @@ bool Node::has_been_explored(thread_id_t tid)
  */
 bool Node::backtrack_empty()
 {
-	return numBacktracks == 0;
+	return (numBacktracks == 0);
+}
+
+
+/**
+ * Checks whether the readsfrom set for this node is empty.
+ * @return true if the readsfrom set is empty.
+ */
+bool Node::readsfrom_empty() {
+	return ((read_from_index+1)>=may_read_from.size());
 }
 
 /**
@@ -104,13 +114,14 @@ bool Node::set_backtrack(thread_id_t id)
 
 thread_id_t Node::get_next_backtrack()
 {
-	/* TODO: find next backtrack */
+	/** @todo Find next backtrack */
 	unsigned int i;
 	for (i = 0; i < backtrack.size(); i++)
 		if (backtrack[i] == true)
 			break;
-	if (i >= backtrack.size())
-		return THREAD_ID_T_NONE;
+	/* Backtrack set was empty? */
+	ASSERT(i != backtrack.size());
+
 	backtrack[i] = false;
 	numBacktracks--;
 	return int_to_id(i);
@@ -130,6 +141,27 @@ void Node::add_read_from(const ModelAction *act)
 	may_read_from.push_back(act);
 }
 
+/**
+ * Gets the next 'may_read_from' action from this Node. Only valid for a node
+ * where this->action is a 'read'.
+ * @todo Perform reads_from backtracking/replay properly, so that this function
+ * may remove elements from may_read_from
+ * @return The first element in may_read_from
+ */
+const ModelAction * Node::get_read_from() {
+	ASSERT(read_from_index<may_read_from.size());
+	return may_read_from[read_from_index];
+}
+
+/**
+ * Increments the index into the readsfrom set to explore the next item.
+ * @return Returns false if we have explored all items.
+ */
+bool Node::increment_read_from() {
+	read_from_index++;
+	return (read_from_index<may_read_from.size());
+}
+
 void Node::explore(thread_id_t tid)
 {
 	int i = id_to_int(tid);
@@ -181,17 +213,14 @@ ModelAction * NodeStack::explore_action(ModelAction *act)
 	DBG();
 
 	ASSERT(!node_list.empty());
+	node_list_t::iterator it=iter;
+	it++;
 
-	if (get_head()->has_been_explored(act->get_tid())) {
+	if (it != node_list.end()) {
 		iter++;
 		return (*iter)->get_action();
 	}
 
-	/* Diverging from previous execution; clear out remainder of list */
-	node_list_t::iterator it = iter;
-	it++;
-	clear_node_list(&node_list, it, node_list.end());
-
 	/* Record action */
 	get_head()->explore_child(act);
 	node_list.push_back(new Node(act, get_head(), model->get_num_threads()));
@@ -200,6 +229,23 @@ ModelAction * NodeStack::explore_action(ModelAction *act)
 	return NULL;
 }
 
+/**
+ * Empties the stack of all trailing nodes after a given position and calls the
+ * destructor for each. This function is provided an offset which determines
+ * how many nodes (relative to the current replay state) to save before popping
+ * the stack.
+ * @param numAhead gives the number of Nodes (including this Node) to skip over
+ * before removing nodes.
+ */
+void NodeStack::pop_restofstack(int numAhead)
+{
+	/* Diverging from previous execution; clear out remainder of list */
+	node_list_t::iterator it = iter;
+	while (numAhead--)
+		it++;
+	clear_node_list(&node_list, it, node_list.end());
+}
+
 Node * NodeStack::get_head()
 {
 	if (node_list.empty())