From 62dbff8dbca80ded5959e88ec9c177bef9108546 Mon Sep 17 00:00:00 2001
From: Brian Norris <banorris@uci.edu>
Date: Tue, 5 Feb 2013 13:44:32 -0800
Subject: [PATCH] cyclegraph: return 'added' status for addEdge()

The ModelChecker would like to know if it's adding a new edge, or just
and existing edge. If the edge is not new, then there are fewer
resulting update checks needed.
---
 cyclegraph.cc | 12 +++++++++---
 cyclegraph.h  |  9 +++++----
 2 files changed, 14 insertions(+), 7 deletions(-)

diff --git a/cyclegraph.cc b/cyclegraph.cc
index 3bb5ab8..eaddc8e 100644
--- a/cyclegraph.cc
+++ b/cyclegraph.cc
@@ -168,13 +168,16 @@ bool CycleGraph::mergeNodes(CycleNode *w_node, CycleNode *p_node,
  * Adds an edge between two CycleNodes.
  * @param fromnode The edge comes from this CycleNode
  * @param tonode The edge points to this CycleNode
+ * @return True, if new edge(s) are added; otherwise false
  */
-void CycleGraph::addNodeEdge(CycleNode *fromnode, CycleNode *tonode)
+bool CycleGraph::addNodeEdge(CycleNode *fromnode, CycleNode *tonode)
 {
+	bool added;
+
 	if (!hasCycles)
 		hasCycles = checkReachable(tonode, fromnode);
 
-	if (fromnode->addEdge(tonode))
+	if ((added = fromnode->addEdge(tonode)))
 		rollbackvector.push_back(fromnode);
 
 	/*
@@ -186,9 +189,12 @@ void CycleGraph::addNodeEdge(CycleNode *fromnode, CycleNode *tonode)
 		if (!hasCycles)
 			hasCycles = checkReachable(tonode, rmwnode);
 
-		if (rmwnode->addEdge(tonode))
+		if (rmwnode->addEdge(tonode)) {
 			rollbackvector.push_back(rmwnode);
+			added = true;
+		}
 	}
+	return added;
 }
 
 /**
diff --git a/cyclegraph.h b/cyclegraph.h
index 83d3db2..749abf8 100644
--- a/cyclegraph.h
+++ b/cyclegraph.h
@@ -28,7 +28,7 @@ class CycleGraph {
 	~CycleGraph();
 
 	template <typename T, typename U>
-	void addEdge(const T from, const U to);
+	bool addEdge(const T from, const U to);
 
 	bool checkForCycles() const;
 	void addRMWEdge(const ModelAction *from, const ModelAction *rmw);
@@ -50,7 +50,7 @@ class CycleGraph {
 
 	SNAPSHOTALLOC
  private:
-	void addNodeEdge(CycleNode *fromnode, CycleNode *tonode);
+	bool addNodeEdge(CycleNode *fromnode, CycleNode *tonode);
 	void putNode(const ModelAction *act, CycleNode *node);
 	CycleNode * getNode(const ModelAction *act);
 	CycleNode * getNode(const Promise *promise);
@@ -141,9 +141,10 @@ class CycleNode {
  *
  * @param to The edge points to this object, of type T
  * @param from The edge comes from this object, of type U
+ * @return True, if new edge(s) are added; otherwise false
  */
 template <typename T, typename U>
-void CycleGraph::addEdge(const T from, const U to)
+bool CycleGraph::addEdge(const T from, const U to)
 {
 	ASSERT(from);
 	ASSERT(to);
@@ -151,7 +152,7 @@ void CycleGraph::addEdge(const T from, const U to)
 	CycleNode *fromnode = getNode(from);
 	CycleNode *tonode = getNode(to);
 
-	addNodeEdge(fromnode, tonode);
+	return addNodeEdge(fromnode, tonode);
 }
 
 /**
-- 
2.34.1