X-Git-Url: http://plrg.eecs.uci.edu/git/?p=model-checker.git;a=blobdiff_plain;f=cyclegraph.cc;h=3168923a8c0f260c137755e7775f99a643ab96a5;hp=dad8b7acb6975b0caccc1887394788b9f9dfff04;hb=b8084847aa9aeec879968c6879d7e6a20c08ea1f;hpb=dd0190cef49ef760f8d86a6e92dd6eeb07197854

diff --git a/cyclegraph.cc b/cyclegraph.cc
index dad8b7a..3168923 100644
--- a/cyclegraph.cc
+++ b/cyclegraph.cc
@@ -2,12 +2,21 @@
 #include "action.h"
 
 /** Initializes a CycleGraph object. */
-CycleGraph::CycleGraph() {
-	hasCycles=false;
+CycleGraph::CycleGraph() :
+	hasCycles(false)
+{
 }
 
-/** Returns the CycleNode for a given ModelAction. */
-CycleNode * CycleGraph::getNode(ModelAction * action) {
+/** CycleGraph destructor */
+CycleGraph::~CycleGraph() {
+}
+
+/**
+ * @brief Returns the CycleNode corresponding to a given ModelAction
+ * @param action The ModelAction to find a node for
+ * @return The CycleNode paired with this action
+ */
+CycleNode * CycleGraph::getNode(const ModelAction *action) {
 	CycleNode *node=actionToNode.get(action);
 	if (node==NULL) {
 		node=new CycleNode(action);
@@ -16,18 +25,84 @@ CycleNode * CycleGraph::getNode(ModelAction * action) {
 	return node;
 }
 
-/** Adds an edge between two ModelActions. */
-void CycleGraph::addEdge(ModelAction *from, ModelAction *to) {
+/**
+ * Adds an edge between two ModelActions. The ModelAction @a to is ordered
+ * after the ModelAction @a from.
+ * @param to The edge points to this ModelAction
+ * @param from The edge comes from this ModelAction
+ */
+void CycleGraph::addEdge(const ModelAction *from, const ModelAction *to) {
 	CycleNode *fromnode=getNode(from);
 	CycleNode *tonode=getNode(to);
+
 	if (!hasCycles) {
 		// Check for Cycles
-		hasCycles=checkReachable(fromnode, tonode);
+		hasCycles=checkReachable(tonode, fromnode);
 	}
 	fromnode->addEdge(tonode);
+
+	CycleNode * rmwnode=fromnode->getRMW();
+
+	//If the fromnode has a rmwnode that is not the tonode, we
+	//should add an edge between its rmwnode and the tonode
+
+	if (rmwnode!=NULL&&rmwnode!=tonode) {
+		if (!hasCycles) {
+			// Check for Cycles
+			hasCycles=checkReachable(tonode, rmwnode);
+		}
+		rmwnode->addEdge(tonode);
+	}
+}
+
+/** Handles special case of a RMW action.  The ModelAction rmw reads
+ *  from the ModelAction from.  The key differences are: (1) no write
+ *  can occur in between the rmw and the from action.  Only one RMW
+ *  action can read from a given write.
+ */
+void CycleGraph::addRMWEdge(const ModelAction *from, const ModelAction *rmw) {
+	CycleNode *fromnode=getNode(from);
+	CycleNode *rmwnode=getNode(rmw);
+
+	/* Two RMW actions cannot read from the same write. */
+	if (fromnode->setRMW(rmwnode)) {
+		hasCycles=true;
+	}
+
+	/* Transfer all outgoing edges from the from node to the rmw node */
+	/* This process cannot add a cycle because rmw should not have any
+		 incoming edges yet.*/
+	std::vector<CycleNode *> * edges=fromnode->getEdges();
+	for(unsigned int i=0;i<edges->size();i++) {
+		CycleNode * tonode=(*edges)[i];
+		rmwnode->addEdge(tonode);
+	}
+
+	fromnode->addEdge(rmwnode);
+}
+
+/**
+ * Checks whether one ModelAction can reach another.
+ * @param from The ModelAction from which to begin exploration
+ * @param to The ModelAction to reach
+ * @return True, @a from can reach @a to; otherwise, false
+ */
+bool CycleGraph::checkReachable(const ModelAction *from, const ModelAction *to) {
+	CycleNode *fromnode = actionToNode.get(from);
+	CycleNode *tonode = actionToNode.get(to);
+
+	if (!fromnode || !tonode)
+		return false;
+
+	return checkReachable(fromnode, tonode);
 }
 
-/** Checks whether the first CycleNode can reach the second one. */
+/**
+ * Checks whether one CycleNode can reach another.
+ * @param from The CycleNode from which to begin exploration
+ * @param to The CycleNode to reach
+ * @return True, @a from can reach @a to; otherwise, false
+ */
 bool CycleGraph::checkReachable(CycleNode *from, CycleNode *to) {
 	std::vector<CycleNode *> queue;
 	HashTable<CycleNode *, CycleNode *, uintptr_t, 4> discovered;
@@ -51,22 +126,47 @@ bool CycleGraph::checkReachable(CycleNode *from, CycleNode *to) {
 	return false;
 }
 
-/** Returns whether a CycleGraph contains cycles. */
+/** @returns whether a CycleGraph contains cycles. */
 bool CycleGraph::checkForCycles() {
 	return hasCycles;
 }
 
-/** Constructor for a CycleNode. */
-CycleNode::CycleNode(ModelAction *modelaction) {
-	action=modelaction;
+/**
+ * Constructor for a CycleNode.
+ * @param modelaction The ModelAction for this node
+ */
+CycleNode::CycleNode(const ModelAction *modelaction) :
+	action(modelaction),
+	hasRMW(NULL)
+{
 }
 
-/** Returns a vector of the edges from a CycleNode. */
+/** @returns a vector of the edges from a CycleNode. */
 std::vector<CycleNode *> * CycleNode::getEdges() {
 	return &edges;
 }
 
-/** Adds an edge to a CycleNode. */
-void CycleNode::addEdge(CycleNode * node) {
+/**
+ * Adds an edge from this CycleNode to another CycleNode.
+ * @param node The node to which we add a directed edge
+ */
+void CycleNode::addEdge(CycleNode *node) {
 	edges.push_back(node);
 }
+
+/** @returns the RMW CycleNode that reads from the current CycleNode */
+CycleNode * CycleNode::getRMW() {
+	return hasRMW;
+}
+
+/**
+ * Set a RMW action node that reads from the current CycleNode.
+ * @param node The RMW that reads from the current node
+ * @return True, if this node already was read by another RMW; false otherwise
+ * @see CycleGraph::addRMWEdge
+ */
+bool CycleNode::setRMW(CycleNode *node) {
+	CycleNode * oldhasRMW=hasRMW;
+	hasRMW=node;
+	return (oldhasRMW!=NULL);
+}