#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() :
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 destructor */
CycleGraph::~CycleGraph()
{
+ delete queue;
delete discovered;
}
#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)
-{
- const ModelAction *reader = promise->get_action();
- readerToPromiseNode.put(reader, node);
-}
-
-/**
- * @brief Remove the Promise node from the graph
- * @param promise The promise to remove from the graph
- */
-void CycleGraph::erasePromiseNode(const Promise *promise)
-{
- const ModelAction *reader = promise->get_action();
- readerToPromiseNode.put(reader, NULL);
-}
-
/** @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 readerToPromiseNode.get(promise->get_action());
-}
-
/**
* @brief Returns the CycleNode corresponding to a given ModelAction
*
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;
-}
-
-/**
- * @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);
- 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.
- * @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 the RMW */
- CycleNode *promise_rmw = p_node->getRMW();
- if (promise_rmw && promise_rmw != w_node->getRMW() && w_node->setRMW(promise_rmw)) {
- hasCycles = true;
- return false;
- }
-
- /* Transfer back edges to w_node */
- while (p_node->getNumBackEdges() > 0) {
- CycleNode *back = p_node->removeBackEdge();
- if (back == w_node)
- continue;
- 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)
- continue;
- 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);
- }
-
- erasePromiseNode(promise);
- delete p_node;
-
- return !hasCycles;
-}
-
/**
* Adds an edge between two CycleNodes.
* @param fromnode The edge comes from this CycleNode
*/
bool CycleGraph::addNodeEdge(CycleNode *fromnode, CycleNode *tonode)
{
- bool added;
-
- if (!hasCycles)
- hasCycles = checkReachable(tonode, fromnode);
-
- if ((added = fromnode->addEdge(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 add
- * an edge between its rmwnode and the tonode
+ * 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 && rmwnode != tonode) {
- if (!hasCycles)
- hasCycles = checkReachable(tonode, rmwnode);
+ if (rmwnode) {
+ while (rmwnode != tonode && rmwnode->getRMW())
+ rmwnode = rmwnode->getRMW();
+
+ if (rmwnode != tonode) {
+ if (rmwnode->addEdge(tonode)) {
+ if (!hasCycles)
+ hasCycles = checkReachable(tonode, rmwnode);
- if (rmwnode->addEdge(tonode)) {
- rollbackvector.push_back(rmwnode);
- added = true;
+ rollbackvector.push_back(rmwnode);
+ }
}
}
- return added;
+ return true;
}
/**
*
* 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.
+ * -# 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
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;
}
/* 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
return addNodeEdge(fromnode, tonode);
}
-/* Instantiate three forms of CycleGraph::addEdge */
+/* 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);
#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);
+}
+
+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 ModelAction *from, const ModelAction *to, const char *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());
- }
+ 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);
+ queue->clear();
+ queue->push_back(from);
discovered->put(from, from);
- while (!queue.empty()) {
- const CycleNode *node = queue.back();
- queue.pop_back();
+ 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);
+ queue->push_back(next);
}
}
}
}
/**
- * Checks whether one ModelAction can reach another ModelAction/Promise
- * @param from The ModelAction from which to begin exploration
+ * 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>
-bool CycleGraph::checkReachable(const ModelAction *from, const T *to) const
+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);
return checkReachable(fromnode, tonode);
}
-/* Instantiate two forms of CycleGraph::checkReachable */
+/* 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;
-
-/** @return True, if the promise has failed; false otherwise */
-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 (!node->is_promise() &&
- 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;
-}
+/** @brief Begin a new sequence of graph additions which can be rolled back */
void CycleGraph::startChanges()
{
ASSERT(rollbackvector.empty());
*/
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
+ * @returns The CycleNode edge indexed by i
*/
CycleNode * CycleNode::getEdge(unsigned int i) const
{
return edges.size();
}
+/**
+ * @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();
* @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)
+static bool vector_remove_node(SnapVector<T>& v, const T n)
{
for (unsigned int i = 0; i < v.size(); i++) {
if (v[i] == n) {
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());
-}