1 #include "cyclegraph.h"
5 /** Initializes a CycleGraph object. */
6 CycleGraph::CycleGraph() :
9 hasRMWViolation(false),
10 oldRMWViolation(false)
14 /** CycleGraph destructor */
15 CycleGraph::~CycleGraph() {
19 * @brief Returns the CycleNode corresponding to a given ModelAction
20 * @param action The ModelAction to find a node for
21 * @return The CycleNode paired with this action
23 CycleNode * CycleGraph::getNode(const ModelAction *action) {
24 CycleNode *node=actionToNode.get(action);
26 node=new CycleNode(action);
27 actionToNode.put(action, node);
28 #if SUPPORT_MOD_ORDER_DUMP
29 nodeList.push_back(node);
36 * Adds an edge between two ModelActions. The ModelAction @a to is ordered
37 * after the ModelAction @a from.
38 * @param to The edge points to this ModelAction
39 * @param from The edge comes from this ModelAction
41 void CycleGraph::addEdge(const ModelAction *from, const ModelAction *to) {
46 CycleNode *fromnode=getNode(from);
47 CycleNode *tonode=getNode(to);
51 hasCycles=checkReachable(tonode, fromnode);
54 if (fromnode->addEdge(tonode))
55 rollbackvector.push_back(fromnode);
58 CycleNode * rmwnode=fromnode->getRMW();
60 //If the fromnode has a rmwnode that is not the tonode, we
61 //should add an edge between its rmwnode and the tonode
63 //If tonode is also a rmw, don't do this check as the execution is
64 //doomed and we'll catch the problem elsewhere, but we want to allow
65 //for the possibility of sending to's write value to rmwnode
67 if (rmwnode!=NULL&&!to->is_rmw()) {
70 hasCycles=checkReachable(tonode, rmwnode);
73 if (rmwnode->addEdge(tonode))
74 rollbackvector.push_back(rmwnode);
78 /** Handles special case of a RMW action. The ModelAction rmw reads
79 * from the ModelAction from. The key differences are: (1) no write
80 * can occur in between the rmw and the from action. Only one RMW
81 * action can read from a given write.
83 void CycleGraph::addRMWEdge(const ModelAction *from, const ModelAction *rmw) {
88 CycleNode *fromnode=getNode(from);
89 CycleNode *rmwnode=getNode(rmw);
91 /* Two RMW actions cannot read from the same write. */
92 if (fromnode->setRMW(rmwnode)) {
95 rmwrollbackvector.push_back(fromnode);
98 /* Transfer all outgoing edges from the from node to the rmw node */
99 /* This process should not add a cycle because either:
100 * (1) The rmw should not have any incoming edges yet if it is the
102 * (2) the fromnode is the new node and therefore it should not
103 * have any outgoing edges.
105 std::vector<CycleNode *> * edges=fromnode->getEdges();
106 for(unsigned int i=0;i<edges->size();i++) {
107 CycleNode * tonode=(*edges)[i];
108 if (tonode!=rmwnode) {
109 if (rmwnode->addEdge(tonode))
110 rollbackvector.push_back(rmwnode);
116 // With promises we could be setting up a cycle here if we aren't
117 // careful...avoid it..
118 hasCycles=checkReachable(rmwnode, fromnode);
120 if(fromnode->addEdge(rmwnode))
121 rollbackvector.push_back(fromnode);
124 #if SUPPORT_MOD_ORDER_DUMP
125 void CycleGraph::dumpGraphToFile(const char *filename) {
127 sprintf(buffer, "%s.dot",filename);
128 FILE *file=fopen(buffer, "w");
129 fprintf(file, "digraph %s {\n",filename);
130 for(unsigned int i=0;i<nodeList.size();i++) {
131 CycleNode *cn=nodeList[i];
132 std::vector<CycleNode *> * edges=cn->getEdges();
133 const ModelAction *action=cn->getAction();
134 fprintf(file, "N%u [label=\"%u, T%u\"];\n",action->get_seq_number(),action->get_seq_number(), action->get_tid());
135 if (cn->getRMW()!=NULL) {
136 fprintf(file, "N%u -> N%u[style=dotted];\n", action->get_seq_number(), cn->getRMW()->getAction()->get_seq_number());
138 for(unsigned int j=0;j<edges->size();j++) {
139 CycleNode *dst=(*edges)[j];
140 const ModelAction *dstaction=dst->getAction();
141 fprintf(file, "N%u -> N%u;\n", action->get_seq_number(), dstaction->get_seq_number());
150 * Checks whether one ModelAction can reach another.
151 * @param from The ModelAction from which to begin exploration
152 * @param to The ModelAction to reach
153 * @return True, @a from can reach @a to; otherwise, false
155 bool CycleGraph::checkReachable(const ModelAction *from, const ModelAction *to) {
156 CycleNode *fromnode = actionToNode.get(from);
157 CycleNode *tonode = actionToNode.get(to);
159 if (!fromnode || !tonode)
162 return checkReachable(fromnode, tonode);
166 * Checks whether one CycleNode can reach another.
167 * @param from The CycleNode from which to begin exploration
168 * @param to The CycleNode to reach
169 * @return True, @a from can reach @a to; otherwise, false
171 bool CycleGraph::checkReachable(CycleNode *from, CycleNode *to) {
172 std::vector<CycleNode *, MyAlloc<CycleNode *> > queue;
173 HashTable<CycleNode *, CycleNode *, uintptr_t, 4, model_malloc, model_calloc, model_free> discovered;
175 queue.push_back(from);
176 discovered.put(from, from);
177 while(!queue.empty()) {
178 CycleNode * node=queue.back();
183 for(unsigned int i=0;i<node->getEdges()->size();i++) {
184 CycleNode *next=(*node->getEdges())[i];
185 if (!discovered.contains(next)) {
186 discovered.put(next,next);
187 queue.push_back(next);
194 void CycleGraph::startChanges() {
195 ASSERT(rollbackvector.size()==0);
196 ASSERT(rmwrollbackvector.size()==0);
197 ASSERT(oldCycles==hasCycles);
198 ASSERT(oldRMWViolation==hasRMWViolation);
201 /** Commit changes to the cyclegraph. */
202 void CycleGraph::commitChanges() {
203 rollbackvector.resize(0);
204 rmwrollbackvector.resize(0);
206 oldRMWViolation=hasRMWViolation;
209 /** Rollback changes to the previous commit. */
210 void CycleGraph::rollbackChanges() {
211 for (unsigned int i = 0; i < rollbackvector.size(); i++) {
212 rollbackvector[i]->popEdge();
215 for (unsigned int i = 0; i < rmwrollbackvector.size(); i++) {
216 rmwrollbackvector[i]->clearRMW();
219 hasCycles = oldCycles;
220 hasRMWViolation = oldRMWViolation;
221 rollbackvector.resize(0);
222 rmwrollbackvector.resize(0);
225 /** @returns whether a CycleGraph contains cycles. */
226 bool CycleGraph::checkForCycles() {
230 bool CycleGraph::checkForRMWViolation() {
231 return hasRMWViolation;
235 * Constructor for a CycleNode.
236 * @param modelaction The ModelAction for this node
238 CycleNode::CycleNode(const ModelAction *modelaction) :
244 /** @returns a vector of the edges from a CycleNode. */
245 std::vector<CycleNode *> * CycleNode::getEdges() {
250 * Adds an edge from this CycleNode to another CycleNode.
251 * @param node The node to which we add a directed edge
253 bool CycleNode::addEdge(CycleNode *node) {
254 for(unsigned int i=0;i<edges.size();i++)
257 edges.push_back(node);
261 /** @returns the RMW CycleNode that reads from the current CycleNode */
262 CycleNode * CycleNode::getRMW() {
267 * Set a RMW action node that reads from the current CycleNode.
268 * @param node The RMW that reads from the current node
269 * @return True, if this node already was read by another RMW; false otherwise
270 * @see CycleGraph::addRMWEdge
272 bool CycleNode::setRMW(CycleNode *node) {