#include "cyclegraph.h"
#include "action.h"
+#include "common.h"
+#include "promise.h"
+#include "model.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)
+{
}
-/** Returns the CycleNode for a given ModelAction. */
-CycleNode * CycleGraph::getNode(ModelAction * action) {
- CycleNode *node=actionToNode.get(action);
- if (node==NULL) {
- node=new CycleNode(action);
- actionToNode.put(action, node);
+/** CycleGraph destructor */
+CycleGraph::~CycleGraph()
+{
+ delete queue;
+ delete discovered;
+}
+
+/**
+ * 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
+}
+
+/**
+ * Add a CycleNode to the graph, corresponding to a Promise
+ * @param promise The Promise that should be added
+ * @param node The CycleNode that corresponds to the Promise
+ */
+void CycleGraph::putNode(const Promise *promise, CycleNode *node)
+{
+ promiseToNode.put(promise, node);
+#if SUPPORT_MOD_ORDER_DUMP
+ nodeList.push_back(node);
+#endif
+}
+
+/**
+ * @brief Remove the Promise node from the graph
+ * @param promise The promise to remove from the graph
+ */
+void CycleGraph::erasePromiseNode(const Promise *promise)
+{
+ promiseToNode.put(promise, NULL);
+#if SUPPORT_MOD_ORDER_DUMP
+ /* Remove the promise node from nodeList */
+ CycleNode *node = getNode_noCreate(promise);
+ for (unsigned int i = 0; i < nodeList.size(); )
+ if (nodeList[i] == node)
+ nodeList.erase(nodeList.begin() + i);
+ else
+ i++;
+#endif
+}
+
+/** @return The corresponding CycleNode, if exists; otherwise NULL */
+CycleNode * CycleGraph::getNode_noCreate(const ModelAction *act) const
+{
+ return actionToNode.get(act);
+}
+
+/** @return The corresponding CycleNode, if exists; otherwise NULL */
+CycleNode * CycleGraph::getNode_noCreate(const Promise *promise) const
+{
+ return promiseToNode.get(promise);
+}
+
+/**
+ * @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;
+}
+
+/**
+ * @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)
+{
+ CycleNode *node = getNode_noCreate(promise);
+ if (node == NULL) {
+ node = new CycleNode(promise);
+ putNode(promise, node);
}
return node;
}
-/** Adds an edge between two ModelActions. */
-void CycleGraph::addEdge(ModelAction *from, ModelAction *to) {
- CycleNode *fromnode=getNode(from);
- CycleNode *tonode=getNode(to);
- if (!hasCycles) {
- // Check for Cycles
- hasCycles=checkReachable(fromnode, tonode);
+/**
+ * Resolve/satisfy a Promise with a particular store ModelAction, taking care
+ * of the CycleGraph cleanups, including merging any necessary CycleNodes.
+ *
+ * @param promise The Promise to resolve
+ * @param writer The store that will resolve this Promise
+ * @return false if the resolution results in a cycle (or fails in some other
+ * way); true otherwise
+ */
+bool CycleGraph::resolvePromise(const Promise *promise, ModelAction *writer)
+{
+ CycleNode *promise_node = promiseToNode.get(promise);
+ CycleNode *w_node = actionToNode.get(writer);
+ ASSERT(promise_node);
+
+ if (w_node)
+ return mergeNodes(w_node, promise_node);
+ /* No existing write-node; just convert the promise-node */
+ promise_node->resolvePromise(writer);
+ erasePromiseNode(promise_node->getPromise());
+ 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.
+ *
+ * @return false if the merge cannot succeed; true otherwise
+ */
+bool CycleGraph::mergeNodes(CycleNode *w_node, CycleNode *p_node)
+{
+ ASSERT(!w_node->is_promise());
+ ASSERT(p_node->is_promise());
+
+ const Promise *promise = p_node->getPromise();
+ if (!promise->is_compatible(w_node->getAction()) ||
+ !promise->same_value(w_node->getAction()))
+ return false;
+
+ /* Transfer the RMW */
+ CycleNode *promise_rmw = p_node->getRMW();
+ if (promise_rmw && promise_rmw != w_node->getRMW() && w_node->setRMW(promise_rmw))
+ return false;
+
+ /* Transfer back edges to w_node */
+ while (p_node->getNumBackEdges() > 0) {
+ CycleNode *back = p_node->removeBackEdge();
+ if (back == w_node)
+ continue;
+ addNodeEdge(back, w_node);
+ if (hasCycles)
+ return false;
+ }
+
+ /* Transfer forward edges to w_node */
+ while (p_node->getNumEdges() > 0) {
+ CycleNode *forward = p_node->removeEdge();
+ if (forward == w_node)
+ continue;
+ addNodeEdge(w_node, forward);
+ if (hasCycles)
+ return false;
+ }
+
+ erasePromiseNode(promise);
+ /* Not deleting p_node, to maintain consistency if mergeNodes() fails */
+
+ 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
+ */
+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 */
+
+ /*
+ * 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();
+
+ if (rmwnode != tonode) {
+ if (rmwnode->addEdge(tonode)) {
+ if (!hasCycles)
+ hasCycles = checkReachable(tonode, rmwnode);
+
+ rollbackvector.push_back(rmwnode);
+ }
+ }
+ }
+ 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:
+ * (1) no write can occur in between the rmw and the from action.
+ * (2) 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 *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);
+
+ /* 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);
+ }
+ }
+
+ addNodeEdge(fromnode, rmwnode);
+}
+/* Instantiate two forms of CycleGraph::addRMWEdge */
+template void CycleGraph::addRMWEdge(const ModelAction *from, const ModelAction *rmw);
+template void CycleGraph::addRMWEdge(const Promise *from, const ModelAction *rmw);
+
+/**
+ * @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);
+
+ CycleNode *fromnode = getNode(from);
+ CycleNode *tonode = getNode(to);
+
+ return addNodeEdge(fromnode, tonode);
+}
+/* Instantiate four forms of CycleGraph::addEdge */
+template bool CycleGraph::addEdge(const ModelAction *from, const ModelAction *to);
+template bool CycleGraph::addEdge(const ModelAction *from, const Promise *to);
+template bool CycleGraph::addEdge(const Promise *from, const ModelAction *to);
+template bool CycleGraph::addEdge(const Promise *from, const Promise *to);
+
+#if SUPPORT_MOD_ORDER_DUMP
+
+static void print_node(FILE *file, const CycleNode *node, int label)
+{
+ if (node->is_promise()) {
+ const Promise *promise = node->getPromise();
+ int idx = model->get_promise_number(promise);
+ fprintf(file, "P%u", idx);
+ if (label) {
+ int first = 1;
+ fprintf(file, " [label=\"P%d, T", idx);
+ for (unsigned int i = 0 ; i < model->get_num_threads(); i++)
+ if (promise->thread_is_available(int_to_id(i))) {
+ fprintf(file, "%s%u", first ? "": ",", i);
+ first = 0;
+ }
+ fprintf(file, "\"]");
+ }
+ } else {
+ 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);
+}
+
+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);
+
+ print_edge(file, fromnode, tonode, prop);
+}
+/* Instantiate two forms of CycleGraph::dot_print_edge */
+template void CycleGraph::dot_print_edge(FILE *file, const Promise *from, const ModelAction *to, const char *prop);
+template void CycleGraph::dot_print_edge(FILE *file, const ModelAction *from, const ModelAction *to, const char *prop);
+
+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);
+ }
+ }
}
- fromnode->addEdge(tonode);
+ return false;
}
-/** 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;
+/**
+ * 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;
+template bool CycleGraph::checkReachable(const ModelAction *from,
+ const Promise *to) const;
+template bool CycleGraph::checkReachable(const Promise *from,
+ const ModelAction *to) const;
+template bool CycleGraph::checkReachable(const Promise *from,
+ const Promise *to) const;
- queue.push_back(from);
- discovered.put(from, from);
- while(!queue.empty()) {
- CycleNode * node=queue.back();
- queue.pop_back();
- if (node==to)
+/** @return True, if the promise has failed; false otherwise */
+bool CycleGraph::checkPromise(const ModelAction *fromact, Promise *promise) const
+{
+ discovered->reset();
+ queue->clear();
+ CycleNode *from = actionToNode.get(fromact);
+
+ queue->push_back(from);
+ discovered->put(from, from);
+ while (!queue->empty()) {
+ const CycleNode *node = queue->back();
+ queue->pop_back();
+
+ if (node->getPromise() == promise)
+ return true;
+ if (!node->is_promise() &&
+ promise->eliminate_thread(node->getAction()->get_tid()))
return true;
- 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);
+ 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() {
+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(ModelAction *modelaction) {
- action=modelaction;
+/**
+ * @brief Constructor for a CycleNode
+ * @param act The ModelAction for this node
+ */
+CycleNode::CycleNode(const ModelAction *act) :
+ action(act),
+ promise(NULL),
+ hasRMW(NULL)
+{
+}
+
+/**
+ * @brief Constructor for a Promise CycleNode
+ * @param promise The Promise which was generated
+ */
+CycleNode::CycleNode(const Promise *promise) :
+ action(NULL),
+ promise(promise),
+ hasRMW(NULL)
+{
+}
+
+/**
+ * @param i The index of the edge to return
+ * @returns The a CycleNode edge indexed by i
+ */
+CycleNode * CycleNode::getEdge(unsigned int i) const
+{
+ return edges[i];
+}
+
+/** @returns The number of edges leaving this CycleNode */
+unsigned int CycleNode::getNumEdges() 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(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;
}
-/** Returns a vector of the edges from a CycleNode. */
-std::vector<CycleNode *> * CycleNode::getEdges() {
- return &edges;
+/**
+ * @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 to a CycleNode. */
-void CycleNode::addEdge(CycleNode * node) {
+/**
+ * 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;
+}
+
+/** @returns the RMW CycleNode that reads from the current CycleNode */
+CycleNode * CycleNode::getRMW() const
+{
+ return hasRMW;
+}
+
+/**
+ * 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;
+}
+
+/**
+ * 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());
}
projects / model-checker.git / blobdiff