#include "cyclegraph.h"
#include "action.h"
#include "common.h"
-#include "promise.h"
-#include "model.h"
+#include "threads-model.h"
+#include "clockvector.h"
/** Initializes a CycleGraph object. */
CycleGraph::CycleGraph() :
- discovered(new HashTable<const CycleNode *, const CycleNode *, uintptr_t, 4, model_malloc, model_calloc, model_free>(16)),
- hasCycles(false),
- oldCycles(false)
+ queue(new SnapVector<const CycleNode *>())
{
}
/** CycleGraph destructor */
CycleGraph::~CycleGraph()
{
- delete discovered;
+ delete queue;
}
/**
return actionToNode.get(act);
}
-/** @return The corresponding CycleNode, if exists; otherwise NULL */
-CycleNode * CycleGraph::getNode_noCreate(const Promise *promise) const
-{
- return readerToPromiseNode.get(promise->get_action());
-}
-
/**
* @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 * CycleGraph::getNode(ModelAction *action)
{
CycleNode *node = getNode_noCreate(action);
if (node == NULL) {
return node;
}
-/**
- * @brief Returns a CycleNode corresponding to a promise
- *
- * Gets (or creates, if none exist) a CycleNode corresponding to a promised
- * value.
- *
- * @param promise The Promise generated by a reader
- * @return The CycleNode corresponding to the Promise
- */
-CycleNode * CycleGraph::getNode(const Promise *promise)
-{
- const ModelAction *reader = promise->get_action();
- CycleNode *node = getNode_noCreate(promise);
- if (node == NULL) {
- node = new CycleNode(promise);
- readerToPromiseNode.put(reader, node);
- }
- return node;
-}
-
-/**
- * @return false if the resolution results in a cycle; true otherwise
- */
-bool CycleGraph::resolvePromise(ModelAction *reader, ModelAction *writer,
- promise_list_t *mustResolve)
-{
- CycleNode *promise_node = readerToPromiseNode.get(reader);
- CycleNode *w_node = actionToNode.get(writer);
- ASSERT(promise_node);
-
- if (w_node)
- return mergeNodes(w_node, promise_node, mustResolve);
- /* No existing write-node; just convert the promise-node */
- promise_node->resolvePromise(writer);
- readerToPromiseNode.put(reader, NULL); /* erase promise_node */
- putNode(writer, promise_node);
- return true;
-}
-
-/**
- * @brief Merge two CycleNodes that represent the same write
- *
- * Note that this operation cannot be rolled back.
- *
- * @param w_node The write ModelAction node with which to merge
- * @param p_node The Promise node to merge. Will be destroyed after this
- * function.
- * @param mustMerge Return (pass-by-reference) any additional Promises that
- * must also be merged with w_node
- *
- * @return false if the merge results in a cycle; true otherwise
- */
-bool CycleGraph::mergeNodes(CycleNode *w_node, CycleNode *p_node,
- promise_list_t *mustMerge)
-{
- ASSERT(!w_node->is_promise());
- ASSERT(p_node->is_promise());
- const Promise *promise = p_node->getPromise();
- if (!promise->is_compatible(w_node->getAction())) {
- hasCycles = true;
- return false;
- }
-
- /* Transfer back edges to w_node */
- while (p_node->getNumBackEdges() > 0) {
- CycleNode *back = p_node->removeBackEdge();
- if (back != w_node) {
- if (back->is_promise()) {
- if (checkReachable(w_node, back)) {
- /* Edge would create cycle; merge instead */
- mustMerge->push_back(back->getPromise());
- if (!mergeNodes(w_node, back, mustMerge))
- return false;
- } else
- back->addEdge(w_node);
- } else
- addNodeEdge(back, w_node);
- }
- }
-
- /* Transfer forward edges to w_node */
- while (p_node->getNumEdges() > 0) {
- CycleNode *forward = p_node->removeEdge();
- if (forward != w_node) {
- if (forward->is_promise()) {
- if (checkReachable(forward, w_node)) {
- mustMerge->push_back(forward->getPromise());
- if (!mergeNodes(w_node, forward, mustMerge))
- return false;
- } else
- w_node->addEdge(forward);
- } else
- addNodeEdge(w_node, forward);
- }
- }
-
- /* erase p_node */
- readerToPromiseNode.put(promise->get_action(), NULL);
- delete p_node;
-
- return !hasCycles;
-}
-
/**
* 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
*/
-void CycleGraph::addNodeEdge(CycleNode *fromnode, CycleNode *tonode)
+void CycleGraph::addNodeEdge(CycleNode *fromnode, CycleNode *tonode, bool forceedge)
{
- if (!hasCycles)
- hasCycles = checkReachable(tonode, fromnode);
-
- if (fromnode->addEdge(tonode))
- rollbackvector.push_back(fromnode);
+ //quick check whether edge is redundant
+ if (checkReachable(fromnode, tonode) && !forceedge) {
+ return;
+ }
/*
- * If the fromnode has a rmwnode that is not the tonode, we should add
- * an edge between its rmwnode and the tonode
+ * If the fromnode has a rmwnode, we should
+ * follow its RMW chain to add an edge at the end.
*/
- CycleNode *rmwnode = fromnode->getRMW();
- if (rmwnode && rmwnode != tonode) {
- if (!hasCycles)
- hasCycles = checkReachable(tonode, rmwnode);
+ while (fromnode->getRMW()) {
+ CycleNode *nextnode = fromnode->getRMW();
+ if (nextnode == tonode)
+ break;
+ fromnode = nextnode;
+ }
- if (rmwnode->addEdge(tonode))
- rollbackvector.push_back(rmwnode);
+ fromnode->addEdge(tonode); //Add edge to edgeSrcNode
+
+ /* Propagate clock vector changes */
+ if (tonode->cv->merge(fromnode->cv)) {
+ queue->push_back(tonode);
+ while(!queue->empty()) {
+ const CycleNode *node = queue->back();
+ queue->pop_back();
+ unsigned int numedges = node->getNumEdges();
+ for(unsigned int i = 0;i < numedges;i++) {
+ CycleNode * enode = node->getEdge(i);
+ if (enode->cv->merge(node->cv))
+ queue->push_back(enode);
+ }
+ }
}
}
*
* Handles special case of a RMW action, where 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.
- * (2) Only one RMW action can read from a given write.
+ * -# 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
* @param rmw The edge points to this ModelAction; this action must read from
- * ModelAction from
+ * the ModelAction from
*/
-void CycleGraph::addRMWEdge(const ModelAction *from, const ModelAction *rmw)
+void CycleGraph::addRMWEdge(ModelAction *from, ModelAction *rmw)
{
ASSERT(from);
ASSERT(rmw);
CycleNode *fromnode = getNode(from);
CycleNode *rmwnode = getNode(rmw);
+ /* We assume that this RMW has no RMW reading from it yet */
+ ASSERT(!rmwnode->getRMW());
- /* Two RMW actions cannot read from the same write. */
- if (fromnode->setRMW(rmwnode))
- hasCycles = true;
- else
- rmwrollbackvector.push_back(fromnode);
+ fromnode->setRMW(rmwnode);
/* Transfer all outgoing edges from the from node to the rmw node */
/* This process should not add a cycle because either:
* (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++) {
+ 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);
}
+ tonode->removeInEdge(fromnode);
+ }
+ fromnode->edges.clear();
+
+ addNodeEdge(fromnode, rmwnode, true);
+}
+
+void CycleGraph::addEdges(SnapList<ModelAction *> * edgeset, ModelAction *to) {
+ for(sllnode<ModelAction*> * it = edgeset->begin();it!=NULL;) {
+ ModelAction *act = it->getVal();
+ CycleNode *node = getNode(act);
+ sllnode<ModelAction*> * it2 = it;
+ it2=it2->getNext();
+ for(;it2!=NULL; ) {
+ ModelAction *act2 = it2->getVal();
+ CycleNode *node2 = getNode(act2);
+ if (checkReachable(node, node2)) {
+ it = edgeset->erase(it);
+ goto endouterloop;
+ } else if (checkReachable(node2, node)) {
+ it2 = edgeset->erase(it2);
+ goto endinnerloop;
+ }
+ it2=it2->getNext();
+endinnerloop:
+ ;
+ }
+ it=it->getNext();
+endouterloop:
+ ;
+ }
+ for(sllnode<ModelAction*> *it = edgeset->begin();it!=NULL;it=it->getNext()) {
+ ModelAction *from = it->getVal();
+ addEdge(from, to, from->get_tid() == to->get_tid());
}
+}
+
+/**
+ * @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
+ */
+
+void CycleGraph::addEdge(ModelAction *from, ModelAction *to)
+{
+ ASSERT(from);
+ ASSERT(to);
+
+ CycleNode *fromnode = getNode(from);
+ CycleNode *tonode = getNode(to);
+
+ addNodeEdge(fromnode, tonode, false);
+}
+
+void CycleGraph::addEdge(ModelAction *from, ModelAction *to, bool forceedge)
+{
+ ASSERT(from);
+ ASSERT(to);
+
+ CycleNode *fromnode = getNode(from);
+ CycleNode *tonode = getNode(to);
- addNodeEdge(fromnode, rmwnode);
+ addNodeEdge(fromnode, tonode, forceedge);
}
#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());
+}
+
+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);
+}
+
+void CycleGraph::dot_print_edge(FILE *file, const ModelAction *from, const ModelAction *to, const char *prop)
+{
+ CycleNode *fromnode = getNode(from);
+ CycleNode *tonode = getNode(to);
+
+ print_edge(file, fromnode, tonode, prop);
+}
+
void CycleGraph::dumpNodes(FILE *file) const
{
- for (unsigned int i = 0; i < nodeList.size(); i++) {
- CycleNode *cn = nodeList[i];
- const ModelAction *action = cn->getAction();
- fprintf(file, "N%u [label=\"%u, T%u\"];\n", action->get_seq_number(), action->get_seq_number(), action->get_tid());
- if (cn->getRMW() != NULL) {
- fprintf(file, "N%u -> N%u[style=dotted];\n", action->get_seq_number(), cn->getRMW()->getAction()->get_seq_number());
- }
- for (unsigned int j = 0; j < cn->getNumEdges(); j++) {
- CycleNode *dst = cn->getEdge(j);
- const ModelAction *dstaction = dst->getAction();
- fprintf(file, "N%u -> N%u;\n", action->get_seq_number(), dstaction->get_seq_number());
- }
+ 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);
}
}
*/
bool CycleGraph::checkReachable(const CycleNode *from, const CycleNode *to) const
{
- std::vector< const CycleNode *, ModelAlloc<const CycleNode *> > queue;
- discovered->reset();
-
- 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;
-}
-
-bool CycleGraph::checkPromise(const ModelAction *fromact, Promise *promise) const
-{
- std::vector< CycleNode *, ModelAlloc<CycleNode *> > queue;
- discovered->reset();
- CycleNode *from = actionToNode.get(fromact);
-
- queue.push_back(from);
- discovered->put(from, from);
- while (!queue.empty()) {
- CycleNode *node = queue.back();
- queue.pop_back();
-
- if (promise->eliminate_thread(node->getAction()->get_tid())) {
- 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;
-}
-
-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;
+ return to->cv->synchronized_since(from->action);
}
-/** Rollback changes to the previous commit. */
-void CycleGraph::rollbackChanges()
+/**
+ * Checks whether one ModelAction can reach another ModelAction
+ * @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) const
{
- for (unsigned int i = 0; i < rollbackvector.size(); i++)
- rollbackvector[i]->popEdge();
+ CycleNode *fromnode = getNode_noCreate(from);
+ CycleNode *tonode = getNode_noCreate(to);
- for (unsigned int i = 0; i < rmwrollbackvector.size(); i++)
- rmwrollbackvector[i]->clearRMW();
+ if (!fromnode || !tonode)
+ return false;
- hasCycles = oldCycles;
- rollbackvector.clear();
- rmwrollbackvector.clear();
+ return checkReachable(fromnode, tonode);
}
-/** @returns whether a CycleGraph contains cycles. */
-bool CycleGraph::checkForCycles() const
-{
- return hasCycles;
+void CycleGraph::freeAction(const ModelAction * act) {
+ CycleNode *cn = actionToNode.remove(act);
+ for(unsigned int i=0;i<cn->edges.size();i++) {
+ CycleNode *dst = cn->edges[i];
+ dst->removeInEdge(cn);
+ }
+ for(unsigned int i=0;i<cn->inedges.size();i++) {
+ CycleNode *src = cn->inedges[i];
+ src->removeEdge(cn);
+ }
+ delete cn;
}
/**
* @brief Constructor for a CycleNode
* @param act The ModelAction for this node
*/
-CycleNode::CycleNode(const ModelAction *act) :
+CycleNode::CycleNode(ModelAction *act) :
action(act),
- promise(NULL),
- hasRMW(NULL)
+ hasRMW(NULL),
+ cv(new ClockVector(NULL, act))
{
}
-/**
- * @brief Constructor for a Promise CycleNode
- * @param promise The Promise which was generated
- */
-CycleNode::CycleNode(const Promise *promise) :
- action(NULL),
- promise(promise),
- hasRMW(NULL)
-{
+CycleNode::~CycleNode() {
+ delete cv;
+}
+
+void CycleNode::removeInEdge(CycleNode *src) {
+ for(unsigned int i=0;i < inedges.size();i++) {
+ if (inedges[i] == src) {
+ inedges[i] = inedges[inedges.size()-1];
+ inedges.pop_back();
+ break;
+ }
+ }
+}
+
+void CycleNode::removeEdge(CycleNode *dst) {
+ for(unsigned int i=0;i < edges.size();i++) {
+ if (edges[i] == dst) {
+ edges[i] = edges[edges.size()-1];
+ edges.pop_back();
+ break;
+ }
+ }
}
/**
* @param i The index of the edge to return
- * @returns The a CycleNode edge indexed by i
+ * @returns The CycleNode edge indexed by i
*/
CycleNode * CycleNode::getEdge(unsigned int i) const
{
return edges.size();
}
-CycleNode * CycleNode::getBackEdge(unsigned int i) const
-{
- return back_edges[i];
-}
-
-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(std::vector<T, SnapshotAlloc<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
+ * @param i The index of the edge to return
+ * @returns The CycleNode edge indexed by i
*/
-CycleNode * CycleNode::removeEdge()
+CycleNode * CycleNode::getInEdge(unsigned int i) const
{
- if (edges.empty())
- return NULL;
-
- CycleNode *ret = edges.back();
- edges.pop_back();
- vector_remove_node(ret->back_edges, this);
- return ret;
+ return inedges[i];
}
-/**
- * @brief Remove a (back) edge from this CycleNode
- * @return The CycleNode which was popped, if one exists; otherwise NULL
- */
-CycleNode * CycleNode::removeBackEdge()
+/** @returns The number of edges leaving this CycleNode */
+unsigned int CycleNode::getNumInEdges() const
{
- if (back_edges.empty())
- return NULL;
-
- CycleNode *ret = back_edges.back();
- back_edges.pop_back();
- vector_remove_node(ret->edges, this);
- return ret;
+ return inedges.size();
}
/**
* @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)
+void CycleNode::addEdge(CycleNode *node)
{
- for (unsigned int i = 0; i < edges.size(); i++)
+ for (unsigned int i = 0;i < edges.size();i++)
if (edges[i] == node)
- return false;
+ return;
edges.push_back(node);
- node->back_edges.push_back(this);
- return true;
+ node->inedges.push_back(this);
}
/** @returns the RMW CycleNode that reads from the current CycleNode */
hasRMW = node;
return false;
}
-
-/**
- * Convert a Promise CycleNode into a concrete-valued CycleNode. Should only be
- * used when there's no existing ModelAction CycleNode for this write.
- *
- * @param writer The ModelAction which wrote the future value represented by
- * this CycleNode
- */
-void CycleNode::resolvePromise(const ModelAction *writer)
-{
- ASSERT(is_promise());
- ASSERT(promise->is_compatible(writer));
- action = writer;
- promise = NULL;
- ASSERT(!is_promise());
-}
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