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) {
45 CycleNode *fromnode=getNode(from);
46 CycleNode *tonode=getNode(to);
50 hasCycles=checkReachable(tonode, fromnode);
53 if (fromnode->addEdge(tonode))
54 rollbackvector.push_back(fromnode);
57 CycleNode * rmwnode=fromnode->getRMW();
59 //If the fromnode has a rmwnode that is not the tonode, we
60 //should add an edge between its rmwnode and the tonode
62 //If tonode is also a rmw, don't do this check as the execution is
63 //doomed and we'll catch the problem elsewhere, but we want to allow
64 //for the possibility of sending to's write value to rmwnode
66 if (rmwnode!=NULL&&!to->is_rmw()) {
69 hasCycles=checkReachable(tonode, rmwnode);
72 if (rmwnode->addEdge(tonode))
73 rollbackvector.push_back(rmwnode);
77 /** Handles special case of a RMW action. The ModelAction rmw reads
78 * from the ModelAction from. The key differences are: (1) no write
79 * can occur in between the rmw and the from action. Only one RMW
80 * action can read from a given write.
82 void CycleGraph::addRMWEdge(const ModelAction *from, const ModelAction *rmw) {
86 CycleNode *fromnode=getNode(from);
87 CycleNode *rmwnode=getNode(rmw);
89 /* Two RMW actions cannot read from the same write. */
90 if (fromnode->setRMW(rmwnode)) {
93 rmwrollbackvector.push_back(fromnode);
96 /* Transfer all outgoing edges from the from node to the rmw node */
97 /* This process should not add a cycle because either:
98 * (1) The rmw should not have any incoming edges yet if it is the
100 * (2) the fromnode is the new node and therefore it should not
101 * have any outgoing edges.
103 std::vector<CycleNode *> * edges=fromnode->getEdges();
104 for(unsigned int i=0;i<edges->size();i++) {
105 CycleNode * tonode=(*edges)[i];
106 if (tonode!=rmwnode) {
107 if (rmwnode->addEdge(tonode))
108 rollbackvector.push_back(rmwnode);
114 // With promises we could be setting up a cycle here if we aren't
115 // careful...avoid it..
116 hasCycles=checkReachable(rmwnode, fromnode);
118 if(fromnode->addEdge(rmwnode))
119 rollbackvector.push_back(fromnode);
122 #if SUPPORT_MOD_ORDER_DUMP
123 void CycleGraph::dumpGraphToFile(const char *filename) {
125 sprintf(buffer, "%s.dot",filename);
126 FILE *file=fopen(buffer, "w");
127 fprintf(file, "digraph %s {\n",filename);
128 for(unsigned int i=0;i<nodeList.size();i++) {
129 CycleNode *cn=nodeList[i];
130 std::vector<CycleNode *> * edges=cn->getEdges();
131 const ModelAction *action=cn->getAction();
132 fprintf(file, "N%u [label=\"%u, T%u\"];\n",action->get_seq_number(),action->get_seq_number(), action->get_tid());
133 if (cn->getRMW()!=NULL) {
134 fprintf(file, "N%u -> N%u[style=dotted];\n", action->get_seq_number(), cn->getRMW()->getAction()->get_seq_number());
136 for(unsigned int j=0;j<edges->size();j++) {
137 CycleNode *dst=(*edges)[j];
138 const ModelAction *dstaction=dst->getAction();
139 fprintf(file, "N%u -> N%u;\n", action->get_seq_number(), dstaction->get_seq_number());
148 * Checks whether one ModelAction can reach another.
149 * @param from The ModelAction from which to begin exploration
150 * @param to The ModelAction to reach
151 * @return True, @a from can reach @a to; otherwise, false
153 bool CycleGraph::checkReachable(const ModelAction *from, const ModelAction *to) {
154 CycleNode *fromnode = actionToNode.get(from);
155 CycleNode *tonode = actionToNode.get(to);
157 if (!fromnode || !tonode)
160 return checkReachable(fromnode, tonode);
164 * Checks whether one CycleNode can reach another.
165 * @param from The CycleNode from which to begin exploration
166 * @param to The CycleNode to reach
167 * @return True, @a from can reach @a to; otherwise, false
169 bool CycleGraph::checkReachable(CycleNode *from, CycleNode *to) {
170 std::vector<CycleNode *, MyAlloc<CycleNode *> > queue;
171 HashTable<CycleNode *, CycleNode *, uintptr_t, 4, MYMALLOC, MYCALLOC, MYFREE> discovered;
173 queue.push_back(from);
174 discovered.put(from, from);
175 while(!queue.empty()) {
176 CycleNode * node=queue.back();
181 for(unsigned int i=0;i<node->getEdges()->size();i++) {
182 CycleNode *next=(*node->getEdges())[i];
183 if (!discovered.contains(next)) {
184 discovered.put(next,next);
185 queue.push_back(next);
192 void CycleGraph::startChanges() {
193 ASSERT(rollbackvector.size()==0);
194 ASSERT(rmwrollbackvector.size()==0);
195 ASSERT(oldCycles==hasCycles);
196 ASSERT(oldRMWViolation==hasRMWViolation);
199 /** Commit changes to the cyclegraph. */
200 void CycleGraph::commitChanges() {
201 rollbackvector.resize(0);
202 rmwrollbackvector.resize(0);
204 oldRMWViolation=hasRMWViolation;
207 /** Rollback changes to the previous commit. */
208 void CycleGraph::rollbackChanges() {
209 for (unsigned int i = 0; i < rollbackvector.size(); i++) {
210 rollbackvector[i]->popEdge();
213 for (unsigned int i = 0; i < rmwrollbackvector.size(); i++) {
214 rmwrollbackvector[i]->clearRMW();
217 hasCycles = oldCycles;
218 hasRMWViolation = oldRMWViolation;
219 rollbackvector.resize(0);
220 rmwrollbackvector.resize(0);
223 /** @returns whether a CycleGraph contains cycles. */
224 bool CycleGraph::checkForCycles() {
228 bool CycleGraph::checkForRMWViolation() {
229 return hasRMWViolation;
233 * Constructor for a CycleNode.
234 * @param modelaction The ModelAction for this node
236 CycleNode::CycleNode(const ModelAction *modelaction) :
242 /** @returns a vector of the edges from a CycleNode. */
243 std::vector<CycleNode *> * CycleNode::getEdges() {
248 * Adds an edge from this CycleNode to another CycleNode.
249 * @param node The node to which we add a directed edge
251 bool CycleNode::addEdge(CycleNode *node) {
252 for(unsigned int i=0;i<edges.size();i++)
255 edges.push_back(node);
259 /** @returns the RMW CycleNode that reads from the current CycleNode */
260 CycleNode * CycleNode::getRMW() {
265 * Set a RMW action node that reads from the current CycleNode.
266 * @param node The RMW that reads from the current node
267 * @return True, if this node already was read by another RMW; false otherwise
268 * @see CycleGraph::addRMWEdge
270 bool CycleNode::setRMW(CycleNode *node) {