#include "cyclegraph.h"
#include "action.h"
+#include "common.h"
+#include "threads-model.h"
/** Initializes a CycleGraph object. */
-CycleGraph::CycleGraph() {
- hasCycles=false;
+CycleGraph::CycleGraph() :
+ discovered(new HashTable<const CycleNode *, const CycleNode *, uintptr_t, 4, model_malloc, model_calloc, model_free>(16)),
+ queue(new ModelVector<const CycleNode *>()),
+ hasCycles(false),
+ oldCycles(false)
+{
}
-CycleGraph::~CycleGraph() {
+/** CycleGraph destructor */
+CycleGraph::~CycleGraph()
+{
+ delete queue;
+ delete discovered;
}
-/** 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);
- actionToNode.put(action, node);
+/**
+ * Add a CycleNode to the graph, corresponding to a store ModelAction
+ * @param act The write action that should be added
+ * @param node The CycleNode that corresponds to the store
+ */
+void CycleGraph::putNode(const ModelAction *act, CycleNode *node)
+{
+ actionToNode.put(act, node);
+#if SUPPORT_MOD_ORDER_DUMP
+ nodeList.push_back(node);
+#endif
+}
+
+/** @return The corresponding CycleNode, if exists; otherwise NULL */
+CycleNode * CycleGraph::getNode_noCreate(const ModelAction *act) const
+{
+ return actionToNode.get(act);
+}
+
+/**
+ * @brief Returns the CycleNode corresponding to a given ModelAction
+ *
+ * Gets (or creates, if none exist) a CycleNode corresponding to a 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 = getNode_noCreate(action);
+ if (node == NULL) {
+ node = new CycleNode(action);
+ putNode(action, node);
}
return node;
}
-/** Adds an edge between two ModelActions. */
+/**
+ * Adds an edge between two CycleNodes.
+ * @param fromnode The edge comes from this CycleNode
+ * @param tonode The edge points to this CycleNode
+ * @return True, if new edge(s) are added; otherwise false
+ */
+bool CycleGraph::addNodeEdge(CycleNode *fromnode, CycleNode *tonode)
+{
+ if (fromnode->addEdge(tonode)) {
+ rollbackvector.push_back(fromnode);
+ if (!hasCycles)
+ hasCycles = checkReachable(tonode, fromnode);
+ } else
+ return false; /* No new edge */
-//the event to happens after the event from
+ /*
+ * 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) {
+ while (rmwnode != tonode && rmwnode->getRMW())
+ rmwnode = rmwnode->getRMW();
-void CycleGraph::addEdge(const ModelAction *to, const ModelAction *from) {
- CycleNode *fromnode=getNode(from);
- CycleNode *tonode=getNode(to);
+ if (rmwnode != tonode) {
+ if (rmwnode->addEdge(tonode)) {
+ if (!hasCycles)
+ hasCycles = checkReachable(tonode, rmwnode);
- if (!hasCycles) {
- // Check for Cycles
- hasCycles=checkReachable(tonode, fromnode);
+ rollbackvector.push_back(rmwnode);
+ }
+ }
}
- fromnode->addEdge(tonode);
+ return true;
+}
+
+/**
+ * @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/Promise from. The key differences are:
+ * -# 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
+ * the ModelAction/Promise from
+ */
+template <typename T>
+void CycleGraph::addRMWEdge(const T *from, const ModelAction *rmw)
+{
+ ASSERT(from);
+ ASSERT(rmw);
- CycleNode * rmwnode=fromnode->getRMW();
+ CycleNode *fromnode = getNode(from);
+ CycleNode *rmwnode = getNode(rmw);
- //If the fromnode has a rmwnode that is not the tonode, we
- //should add an edge between its rmwnode and the tonode
+ /* We assume that this RMW has no RMW reading from it yet */
+ ASSERT(!rmwnode->getRMW());
- if (rmwnode!=NULL&&rmwnode!=tonode) {
- if (!hasCycles) {
- // Check for Cycles
- hasCycles=checkReachable(tonode, rmwnode);
+ /* 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 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.
+ */
+ for (unsigned int i = 0;i < fromnode->getNumEdges();i++) {
+ CycleNode *tonode = fromnode->getEdge(i);
+ if (tonode != rmwnode) {
+ if (rmwnode->addEdge(tonode))
+ rollbackvector.push_back(rmwnode);
}
- rmwnode->addEdge(tonode);
}
+
+ addNodeEdge(fromnode, rmwnode);
}
+/* Instantiate two forms of CycleGraph::addRMWEdge */
+template void CycleGraph::addRMWEdge(const ModelAction *from, const ModelAction *rmw);
-//event rmw that reads from the node from
+/**
+ * @brief Adds an edge between objects
+ *
+ * This function will add an edge between any two objects which can be
+ * associated with a CycleNode. That is, if they have a CycleGraph::getNode
+ * implementation.
+ *
+ * The object to is ordered after the object from.
+ *
+ * @param to The edge points to this object, of type T
+ * @param from The edge comes from this object, of type U
+ * @return True, if new edge(s) are added; otherwise false
+ */
+template <typename T, typename U>
+bool CycleGraph::addEdge(const T *from, const U *to)
+{
+ ASSERT(from);
+ ASSERT(to);
-void CycleGraph::addRMWEdge(const ModelAction *rmw, const ModelAction * from) {
- CycleNode *fromnode=getNode(from);
- CycleNode *rmwnode=getNode(rmw);
+ CycleNode *fromnode = getNode(from);
+ CycleNode *tonode = getNode(to);
- /* Two RMW actions cannot read from the same write. */
- if (fromnode->setRMW(rmwnode)) {
- hasCycles=true;
- }
+ return addNodeEdge(fromnode, tonode);
+}
+/* Instantiate four forms of CycleGraph::addEdge */
+template bool CycleGraph::addEdge(const ModelAction *from, const ModelAction *to);
- /* 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);
- }
+#if SUPPORT_MOD_ORDER_DUMP
+
+static void print_node(FILE *file, const CycleNode *node, int label)
+{
+ const ModelAction *act = node->getAction();
+ modelclock_t idx = act->get_seq_number();
+ fprintf(file, "N%u", idx);
+ if (label)
+ fprintf(file, " [label=\"N%u, T%u\"]", idx, act->get_tid());
+}
- fromnode->addEdge(rmwnode);
+static void print_edge(FILE *file, const CycleNode *from, const CycleNode *to, const char *prop)
+{
+ print_node(file, from, 0);
+ fprintf(file, " -> ");
+ print_node(file, to, 0);
+ if (prop && strlen(prop))
+ fprintf(file, " [%s]", prop);
+ fprintf(file, ";\n");
}
+void CycleGraph::dot_print_node(FILE *file, const ModelAction *act)
+{
+ print_node(file, getNode(act), 1);
+}
-/** Checks whether the first CycleNode can reach the second one. */
-bool CycleGraph::checkReachable(CycleNode *from, CycleNode *to) {
- std::vector<CycleNode *> queue;
- HashTable<CycleNode *, CycleNode *, uintptr_t, 4> discovered;
+template <typename T, typename U>
+void CycleGraph::dot_print_edge(FILE *file, const T *from, const U *to, const char *prop)
+{
+ CycleNode *fromnode = getNode(from);
+ CycleNode *tonode = getNode(to);
- queue.push_back(from);
- discovered.put(from, from);
- while(!queue.empty()) {
- CycleNode * node=queue.back();
- queue.pop_back();
- if (node==to)
- return true;
+ print_edge(file, fromnode, tonode, prop);
+}
+/* Instantiate two forms of CycleGraph::dot_print_edge */
+template void CycleGraph::dot_print_edge(FILE *file, const ModelAction *from, const ModelAction *to, const char *prop);
- for(unsigned int i=0;i<node->getEdges()->size();i++) {
- CycleNode *next=(*node->getEdges())[i];
- if (!discovered.contains(next)) {
- discovered.put(next,next);
- queue.push_back(next);
+void CycleGraph::dumpNodes(FILE *file) const
+{
+ for (unsigned int i = 0;i < nodeList.size();i++) {
+ CycleNode *n = nodeList[i];
+ print_node(file, n, 1);
+ fprintf(file, ";\n");
+ if (n->getRMW())
+ print_edge(file, n, n->getRMW(), "style=dotted");
+ for (unsigned int j = 0;j < n->getNumEdges();j++)
+ print_edge(file, n, n->getEdge(j), NULL);
+ }
+}
+
+void CycleGraph::dumpGraphToFile(const char *filename) const
+{
+ char buffer[200];
+ sprintf(buffer, "%s.dot", filename);
+ FILE *file = fopen(buffer, "w");
+ fprintf(file, "digraph %s {\n", filename);
+ dumpNodes(file);
+ fprintf(file, "}\n");
+ fclose(file);
+}
+#endif
+
+/**
+ * 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(const CycleNode *from, const CycleNode *to) const
+{
+ discovered->reset();
+ queue->clear();
+ queue->push_back(from);
+ discovered->put(from, from);
+ while (!queue->empty()) {
+ const CycleNode *node = queue->back();
+ queue->pop_back();
+ if (node == to)
+ return true;
+ for (unsigned int i = 0;i < node->getNumEdges();i++) {
+ CycleNode *next = node->getEdge(i);
+ if (!discovered->contains(next)) {
+ discovered->put(next, next);
+ queue->push_back(next);
}
}
}
return false;
}
-/** Returns whether a CycleGraph contains cycles. */
-bool CycleGraph::checkForCycles() {
+/**
+ * Checks whether one ModelAction/Promise can reach another ModelAction/Promise
+ * @param from The ModelAction or Promise from which to begin exploration
+ * @param to The ModelAction or Promise to reach
+ * @return True, @a from can reach @a to; otherwise, false
+ */
+template <typename T, typename U>
+bool CycleGraph::checkReachable(const T *from, const U *to) const
+{
+ CycleNode *fromnode = getNode_noCreate(from);
+ CycleNode *tonode = getNode_noCreate(to);
+
+ if (!fromnode || !tonode)
+ return false;
+
+ return checkReachable(fromnode, tonode);
+}
+/* Instantiate four forms of CycleGraph::checkReachable */
+template bool CycleGraph::checkReachable(const ModelAction *from,
+ const ModelAction *to) const;
+
+/** @brief Begin a new sequence of graph additions which can be rolled back */
+void CycleGraph::startChanges()
+{
+ ASSERT(rollbackvector.empty());
+ ASSERT(rmwrollbackvector.empty());
+ ASSERT(oldCycles == hasCycles);
+}
+
+/** Commit changes to the cyclegraph. */
+void CycleGraph::commitChanges()
+{
+ rollbackvector.clear();
+ rmwrollbackvector.clear();
+ oldCycles = hasCycles;
+}
+
+/** Rollback changes to the previous commit. */
+void CycleGraph::rollbackChanges()
+{
+ for (unsigned int i = 0;i < rollbackvector.size();i++)
+ rollbackvector[i]->removeEdge();
+
+ for (unsigned int i = 0;i < rmwrollbackvector.size();i++)
+ rmwrollbackvector[i]->clearRMW();
+
+ hasCycles = oldCycles;
+ rollbackvector.clear();
+ rmwrollbackvector.clear();
+}
+
+/** @returns whether a CycleGraph contains cycles. */
+bool CycleGraph::checkForCycles() const
+{
return hasCycles;
}
-/** Constructor for a CycleNode. */
-CycleNode::CycleNode(const ModelAction *modelaction) {
- action=modelaction;
- hasRMW=NULL;
+/**
+ * @brief Constructor for a CycleNode
+ * @param act The ModelAction for this node
+ */
+CycleNode::CycleNode(const ModelAction *act) :
+ action(act),
+ hasRMW(NULL)
+{
+}
+
+/**
+ * @param i The index of the edge to return
+ * @returns The CycleNode edge indexed by i
+ */
+CycleNode * CycleNode::getEdge(unsigned int i) const
+{
+ return edges[i];
}
-/** Returns a vector of the edges from a CycleNode. */
-std::vector<CycleNode *> * CycleNode::getEdges() {
- return &edges;
+/** @returns The number of edges leaving this CycleNode */
+unsigned int CycleNode::getNumEdges() const
+{
+ return edges.size();
}
-/** Adds an edge to a CycleNode. */
-void CycleNode::addEdge(CycleNode * node) {
+/**
+ * @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();
+}
+
+/**
+ * @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(SnapVector<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
+ * @return True if this edge is a new edge; false otherwise
+ */
+bool CycleNode::addEdge(CycleNode *node)
+{
+ for (unsigned int i = 0;i < edges.size();i++)
+ if (edges[i] == node)
+ return false;
edges.push_back(node);
+ node->back_edges.push_back(this);
+ return true;
}
-CycleNode* CycleNode::getRMW() {
+/** @returns the RMW CycleNode that reads from the current CycleNode */
+CycleNode * CycleNode::getRMW() const
+{
return hasRMW;
}
-bool CycleNode::setRMW(CycleNode * node) {
- CycleNode * oldhasRMW=hasRMW;
- hasRMW=node;
- return (oldhasRMW!=NULL);
+/**
+ * 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;
}