/** Initializes a CycleGraph object. */
CycleGraph::CycleGraph() :
hasCycles(false),
- oldCycles(false)
+ oldCycles(false),
+ hasRMWViolation(false),
+ oldRMWViolation(false)
{
}
//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 tonode is also a rmw, don't do this check as the execution is
+ //doomed and we'll catch the problem elsewhere, but we want to allow
+ //for the possibility of sending to's write value to rmwnode
+
+ if (rmwnode!=NULL&&!to->is_rmw()) {
if (!hasCycles) {
// Check for Cycles
hasCycles=checkReachable(tonode, rmwnode);
/* Two RMW actions cannot read from the same write. */
if (fromnode->setRMW(rmwnode)) {
- hasCycles=true;
+ hasRMWViolation=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.*/
+ /* This process should not add a cycle because either:
+ * (1) The rmw should not have any incoming edges yet if it is the
+ * new node or
+ * (2) the fromnode is the new node and therefore it should not
+ * have any outgoing edges.
+ */
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);
+ if (tonode!=rmwnode) {
+ rollbackvector.push_back(rmwnode);
+ rmwnode->addEdge(tonode);
+ }
}
rollbackvector.push_back(fromnode);
+
+ if (!hasCycles) {
+ // With promises we could be setting up a cycle here if we aren't
+ // careful...avoid it..
+ hasCycles=checkReachable(rmwnode, fromnode);
+ }
fromnode->addEdge(rmwnode);
}
return false;
}
+void CycleGraph::startChanges() {
+ ASSERT(rollbackvector.size()==0);
+ ASSERT(rmwrollbackvector.size()==0);
+ ASSERT(oldCycles==hasCycles);
+ ASSERT(oldRMWViolation==hasRMWViolation);
+}
+
/** Commit changes to the cyclegraph. */
void CycleGraph::commitChanges() {
rollbackvector.resize(0);
rmwrollbackvector.resize(0);
oldCycles=hasCycles;
+ oldRMWViolation=hasRMWViolation;
}
/** Rollback changes to the previous commit. */
}
hasCycles = oldCycles;
+ hasRMWViolation = oldRMWViolation;
rollbackvector.resize(0);
rmwrollbackvector.resize(0);
}
return hasCycles;
}
+bool CycleGraph::checkForRMWViolation() {
+ return hasRMWViolation;
+}
+
/**
* Constructor for a CycleNode.
* @param modelaction The ModelAction for this node