X-Git-Url: http://demsky.eecs.uci.edu/git/?a=blobdiff_plain;f=cyclegraph.cc;h=57f8fc8c42fe0033abbe83d14caa674feeedb1e7;hb=eb07120dfdbb206124f7857016a71b6ef0b9eb99;hp=62cef7c56079e2d2a46587a181340320a9fe0405;hpb=c1372661a92b8d2ba3bc977ebbabf52127354bea;p=model-checker.git

diff --git a/cyclegraph.cc b/cyclegraph.cc
index 62cef7c..57f8fc8 100644
--- a/cyclegraph.cc
+++ b/cyclegraph.cc
@@ -8,9 +8,7 @@
 CycleGraph::CycleGraph() :
 	discovered(new HashTable<const CycleNode *, const CycleNode *, uintptr_t, 4, model_malloc, model_calloc, model_free>(16)),
 	hasCycles(false),
-	oldCycles(false),
-	hasRMWViolation(false),
-	oldRMWViolation(false)
+	oldCycles(false)
 {
 }
 
@@ -92,10 +90,17 @@ void CycleGraph::addEdge(CycleNode *fromnode, CycleNode *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.
+/**
+ * @brief Add an edge between a write and the RMW which reads from it
+ *
+ * Handles special case of a RMW action, where 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.
+ * (2) Only one RMW action can read from a given write.
+ *
+ * @param from The edge comes from this ModelAction
+ * @param rmw The edge points to this ModelAction; this action must read from
+ * ModelAction from
  */
 void CycleGraph::addRMWEdge(const ModelAction *from, const ModelAction *rmw)
 {
@@ -106,11 +111,10 @@ void CycleGraph::addRMWEdge(const ModelAction *from, const ModelAction *rmw)
 	CycleNode *rmwnode = getNode(rmw);
 
 	/* Two RMW actions cannot read from the same write. */
-	if (fromnode->setRMW(rmwnode)) {
-		hasRMWViolation = true;
-	} else {
+	if (fromnode->setRMW(rmwnode))
+		hasCycles = true;
+	else
 		rmwrollbackvector.push_back(fromnode);
-	}
 
 	/* Transfer all outgoing edges from the from node to the rmw node */
 	/* This process should not add a cycle because either:
@@ -236,36 +240,31 @@ bool CycleGraph::checkPromise(const ModelAction *fromact, Promise *promise) cons
 
 void CycleGraph::startChanges()
 {
-	ASSERT(rollbackvector.size() == 0);
-	ASSERT(rmwrollbackvector.size() == 0);
+	ASSERT(rollbackvector.empty());
+	ASSERT(rmwrollbackvector.empty());
 	ASSERT(oldCycles == hasCycles);
-	ASSERT(oldRMWViolation == hasRMWViolation);
 }
 
 /** Commit changes to the cyclegraph. */
 void CycleGraph::commitChanges()
 {
-	rollbackvector.resize(0);
-	rmwrollbackvector.resize(0);
+	rollbackvector.clear();
+	rmwrollbackvector.clear();
 	oldCycles = hasCycles;
-	oldRMWViolation = hasRMWViolation;
 }
 
 /** Rollback changes to the previous commit. */
 void CycleGraph::rollbackChanges()
 {
-	for (unsigned int i = 0; i < rollbackvector.size(); i++) {
+	for (unsigned int i = 0; i < rollbackvector.size(); i++)
 		rollbackvector[i]->popEdge();
-	}
 
-	for (unsigned int i = 0; i < rmwrollbackvector.size(); i++) {
+	for (unsigned int i = 0; i < rmwrollbackvector.size(); i++)
 		rmwrollbackvector[i]->clearRMW();
-	}
 
 	hasCycles = oldCycles;
-	hasRMWViolation = oldRMWViolation;
-	rollbackvector.resize(0);
-	rmwrollbackvector.resize(0);
+	rollbackvector.clear();
+	rmwrollbackvector.clear();
 }
 
 /** @returns whether a CycleGraph contains cycles. */
@@ -274,17 +273,24 @@ bool CycleGraph::checkForCycles() const
 	return hasCycles;
 }
 
-bool CycleGraph::checkForRMWViolation() const
-{
-	return hasRMWViolation;
-}
-
 /**
  * @brief Constructor for a CycleNode
  * @param act The ModelAction for this node
  */
 CycleNode::CycleNode(const ModelAction *act) :
 	action(act),
+	promise(NULL),
+	hasRMW(NULL)
+{
+}
+
+/**
+ * @brief Constructor for a Promise CycleNode
+ * @param promise The Promise which was generated
+ */
+CycleNode::CycleNode(const Promise *promise) :
+	action(NULL),
+	promise(promise),
 	hasRMW(NULL)
 {
 }
@@ -314,6 +320,54 @@ unsigned int CycleNode::getNumBackEdges() const
 	return back_edges.size();
 }
 
+/**
+ * @brief Remove an element from a vector
+ * @param v The vector
+ * @param n The element to remove
+ * @return True if the element was found; false otherwise
+ */
+template <typename T>
+static bool vector_remove_node(std::vector<T, SnapshotAlloc<T> >& v, const T n)
+{
+	for (unsigned int i = 0; i < v.size(); i++) {
+		if (v[i] == n) {
+			v.erase(v.begin() + i);
+			return true;
+		}
+	}
+	return false;
+}
+
+/**
+ * @brief Remove a (forward) edge from this CycleNode
+ * @return The CycleNode which was popped, if one exists; otherwise NULL
+ */
+CycleNode * CycleNode::removeEdge()
+{
+	if (edges.empty())
+		return NULL;
+
+	CycleNode *ret = edges.back();
+	edges.pop_back();
+	vector_remove_node(ret->back_edges, this);
+	return ret;
+}
+
+/**
+ * @brief Remove a (back) edge from this CycleNode
+ * @return The CycleNode which was popped, if one exists; otherwise NULL
+ */
+CycleNode * CycleNode::removeBackEdge()
+{
+	if (back_edges.empty())
+		return NULL;
+
+	CycleNode *ret = back_edges.back();
+	back_edges.pop_back();
+	vector_remove_node(ret->edges, this);
+	return ret;
+}
+
 /**
  * Adds an edge from this CycleNode to another CycleNode.
  * @param node The node to which we add a directed edge