X-Git-Url: http://demsky.eecs.uci.edu/git/?p=model-checker.git;a=blobdiff_plain;f=cyclegraph.cc;h=def51f9671e346251a4f108abe1c78c8d09a8bfe;hp=8d37dea8b9fc6ea6770528e57238df13d2b5a323;hb=6014243b7130f34b7ffd1098da225b0b8de5c328;hpb=5ea8e3d5d861ed363e5ac5f3b20b8181dd197efb

diff --git a/cyclegraph.cc b/cyclegraph.cc
index 8d37dea..def51f9 100644
--- a/cyclegraph.cc
+++ b/cyclegraph.cc
@@ -2,7 +2,6 @@
 #include "action.h"
 #include "common.h"
 #include "promise.h"
-#include "model.h"
 #include "threads-model.h"
 
 /** Initializes a CycleGraph object. */
@@ -198,29 +197,33 @@ bool CycleGraph::mergeNodes(CycleNode *w_node, CycleNode *p_node)
  */
 bool CycleGraph::addNodeEdge(CycleNode *fromnode, CycleNode *tonode)
 {
-	bool added;
-
-	if ((added = fromnode->addEdge(tonode))) {
+	if (fromnode->addEdge(tonode)) {
 		rollbackvector.push_back(fromnode);
 		if (!hasCycles)
 			hasCycles = checkReachable(tonode, fromnode);
-	}
+	} else
+		return false; /* No new edge */
 
 	/*
-	 * If the fromnode has a rmwnode that is not the tonode, we should add
-	 * an edge between its rmwnode and the tonode
+	 * If the fromnode has a rmwnode that is not the tonode, we should
+	 * follow its RMW chain to add an edge at the end, unless we encounter
+	 * tonode along the way
 	 */
 	CycleNode *rmwnode = fromnode->getRMW();
-	if (rmwnode && rmwnode != tonode) {
-		if (rmwnode->addEdge(tonode)) {
-			if (!hasCycles)
-				hasCycles = checkReachable(tonode, rmwnode);
+	if (rmwnode) {
+		while (rmwnode != tonode && rmwnode->getRMW())
+			rmwnode = rmwnode->getRMW();
+
+		if (rmwnode != tonode) {
+			if (rmwnode->addEdge(tonode)) {
+				if (!hasCycles)
+					hasCycles = checkReachable(tonode, rmwnode);
 
-			rollbackvector.push_back(rmwnode);
-			added = true;
+				rollbackvector.push_back(rmwnode);
+			}
 		}
 	}
-	return added;
+	return true;
 }
 
 /**
@@ -228,8 +231,8 @@ bool CycleGraph::addNodeEdge(CycleNode *fromnode, CycleNode *tonode)
  *
  * Handles special case of a RMW action, where the ModelAction rmw reads from
  * the ModelAction/Promise from. The key differences are:
- * (1) no write can occur in between the rmw and the from action.
- * (2) Only one RMW action can read from a given write.
+ *  -# No write can occur in between the @a rmw and @a from actions.
+ *  -# Only one RMW action can read from a given write.
  *
  * @param from The edge comes from this ModelAction/Promise
  * @param rmw The edge points to this ModelAction; this action must read from
@@ -244,6 +247,9 @@ void CycleGraph::addRMWEdge(const T *from, const ModelAction *rmw)
 	CycleNode *fromnode = getNode(from);
 	CycleNode *rmwnode = getNode(rmw);
 
+	/* We assume that this RMW has no RMW reading from it yet */
+	ASSERT(!rmwnode->getRMW());
+
 	/* Two RMW actions cannot read from the same write. */
 	if (fromnode->setRMW(rmwnode))
 		hasCycles = true;
@@ -307,12 +313,12 @@ static void print_node(FILE *file, const CycleNode *node, int label)
 {
 	if (node->is_promise()) {
 		const Promise *promise = node->getPromise();
-		int idx = model->get_promise_number(promise);
+		int idx = promise->get_index();
 		fprintf(file, "P%u", idx);
 		if (label) {
 			int first = 1;
 			fprintf(file, " [label=\"P%d, T", idx);
-			for (unsigned int i = 0 ; i < model->get_num_threads(); i++)
+			for (unsigned int i = 0 ; i < promise->max_available_thread_idx(); i++)
 				if (promise->thread_is_available(int_to_id(i))) {
 					fprintf(file, "%s%u", first ? "": ",", i);
 					first = 0;
@@ -450,9 +456,8 @@ bool CycleGraph::checkPromise(const ModelAction *fromact, Promise *promise) cons
 
 		if (node->getPromise() == promise)
 			return true;
-		if (!node->is_promise() &&
-				promise->eliminate_thread(node->getAction()->get_tid()))
-			return true;
+		if (!node->is_promise())
+			promise->eliminate_thread(node->getAction()->get_tid());
 
 		for (unsigned int i = 0; i < node->getNumEdges(); i++) {
 			CycleNode *next = node->getEdge(i);
@@ -465,6 +470,7 @@ bool CycleGraph::checkPromise(const ModelAction *fromact, Promise *promise) cons
 	return false;
 }
 
+/** @brief Begin a new sequence of graph additions which can be rolled back */
 void CycleGraph::startChanges()
 {
 	ASSERT(rollbackvector.empty());
@@ -524,7 +530,7 @@ CycleNode::CycleNode(const Promise *promise) :
 
 /**
  * @param i The index of the edge to return
- * @returns The a CycleNode edge indexed by i
+ * @returns The CycleNode edge indexed by i
  */
 CycleNode * CycleNode::getEdge(unsigned int i) const
 {
@@ -537,11 +543,16 @@ unsigned int CycleNode::getNumEdges() const
 	return edges.size();
 }
 
+/**
+ * @param i The index of the back edge to return
+ * @returns The CycleNode back-edge indexed by i
+ */
 CycleNode * CycleNode::getBackEdge(unsigned int i) const
 {
 	return back_edges[i];
 }
 
+/** @returns The number of edges entering this CycleNode */
 unsigned int CycleNode::getNumBackEdges() const
 {
 	return back_edges.size();