#include "cyclegraph.h"
+#include "action.h"
-CycleGraph::CycleGraph() {
- hasCycles=false;
+/** Initializes a CycleGraph object. */
+CycleGraph::CycleGraph() :
+ hasCycles(false),
+ oldCycles(false)
+{
}
-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);
return node;
}
-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);
}
+
+ rollbackvector.push_back(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);
+ }
+ rollbackvector.push_back(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;
+ } else {
+ rmwrollbackvector.push_back(fromnode);
+ }
+
+ /* 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];
+ rollbackvector.push_back(rmwnode);
+ rmwnode->addEdge(tonode);
+ }
+ rollbackvector.push_back(fromnode);
+ 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 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<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)) {
return false;
}
-CycleNode::CycleNode(ModelAction *modelaction) {
- action=modelaction;
+/** Commit changes to the cyclegraph. */
+void CycleGraph::commitChanges() {
+ rollbackvector.resize(0);
+ rmwrollbackvector.resize(0);
+ oldCycles=hasCycles;
+}
+
+/** Rollback changes to the previous commit. */
+void CycleGraph::rollbackChanges() {
+ for (unsigned int i = 0; i < rollbackvector.size(); i++) {
+ rollbackvector[i]->popEdge();
+ }
+
+ for (unsigned int i = 0; i < rmwrollbackvector.size(); i++) {
+ rmwrollbackvector[i]->clearRMW();
+ }
+
+ hasCycles = oldCycles;
+ rollbackvector.resize(0);
+ rmwrollbackvector.resize(0);
+}
+
+/** @returns whether a CycleGraph contains cycles. */
+bool CycleGraph::checkForCycles() {
+ return hasCycles;
}
-std::vector<class CycleNode *> * CycleNode::getEdges() {
+/**
+ * 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. */
+std::vector<CycleNode *> * CycleNode::getEdges() {
return &edges;
}
-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) {
+ if (hasRMW!=NULL)
+ return true;
+ hasRMW=node;
+ return false;
+}
projects / model-checker.git / blobdiff