more changes towards keeping track of promises resolved by a given write statement

[model-checker.git] / cyclegraph.cc

diff --git a/cyclegraph.cc b/cyclegraph.cc
index c1fea4f3d0a96f14de433b6aac8b61e6f6479131..f060a00e74362b6f9df99649ffd844f7e416d4b9 100644 (file)
--- a/cyclegraph.cc
+++ b/cyclegraph.cc
@@ -1,10 +1,16 @@
 #include "cyclegraph.h"
+#include "action.h"
 
+/** Initializes a CycleGraph object. */
 CycleGraph::CycleGraph() {
        hasCycles=false;
 }
 
-CycleNode * CycleGraph::getNode(ModelAction * action) {
+CycleGraph::~CycleGraph() {
+}
+
+/** Returns the CycleNode for a given ModelAction. */
+CycleNode * CycleGraph::getNode(const ModelAction * action) {
        CycleNode *node=actionToNode.get(action);
        if (node==NULL) {
                node=new CycleNode(action);
@@ -13,28 +19,74 @@ CycleNode * CycleGraph::getNode(ModelAction * action) {
        return node;
 }
 
-void CycleGraph::addEdge(ModelAction *from, ModelAction *to) {
+/**
+ * Adds an edge between two ModelActions.  The ModelAction to happens after the
+ * ModelAction from.
+ */
+void CycleGraph::addEdge(const ModelAction *to, const ModelAction *from) {
        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 *rmw, const ModelAction * from) {
+       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 the first CycleNode can reach the second one. */
 bool CycleGraph::checkReachable(CycleNode *from, CycleNode *to) {
-       std::vector<class CycleNode *> queue;
-       HashTable<class CycleNode *, class CycleNode *, uintptr_t, 4> discovered;
-       
+       std::vector<CycleNode *> queue;
+       HashTable<CycleNode *, CycleNode *, uintptr_t, 4> discovered;
+
        queue.push_back(from);
        discovered.put(from, from);
        while(!queue.empty()) {
-               class CycleNode * node=queue.back();
+               CycleNode * node=queue.back();
                queue.pop_back();
                if (node==to)
                        return true;
-               
+
                for(unsigned int i=0;i<node->getEdges()->size();i++) {
                        CycleNode *next=(*node->getEdges())[i];
                        if (!discovered.contains(next)) {
@@ -46,14 +98,35 @@ bool CycleGraph::checkReachable(CycleNode *from, CycleNode *to) {
        return false;
 }
 
-CycleNode::CycleNode(ModelAction *modelaction) {
+/** Returns whether a CycleGraph contains cycles. */
+bool CycleGraph::checkForCycles() {
+       return hasCycles;
+}
+
+/** Constructor for a CycleNode. */
+CycleNode::CycleNode(const ModelAction *modelaction) {
        action=modelaction;
+       hasRMW=NULL;
 }
 
-std::vector<class CycleNode *> * CycleNode::getEdges() {
+/** 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) {
        edges.push_back(node);
 }
+
+/** Get 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. */
+bool CycleNode::setRMW(CycleNode * node) {
+       CycleNode * oldhasRMW=hasRMW;
+       hasRMW=node;
+       return (oldhasRMW!=NULL);
+}