#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 readerToPromiseNode.get(promise->get_action());
+}
+
/**
* @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 = actionToNode.get(action);
+ CycleNode *node = getNode_noCreate(action);
if (node == NULL) {
node = new CycleNode(action);
putNode(action, node);
}
/**
- * Adds an edge between two ModelActions. The ModelAction @a to is ordered
- * after the ModelAction @a from.
- * @param to The edge points to this ModelAction
- * @param from The edge comes from this ModelAction
+ * @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
*/
-void CycleGraph::addEdge(const ModelAction *from, const ModelAction *to)
+CycleNode * CycleGraph::getNode(const Promise *promise)
{
- ASSERT(from);
- ASSERT(to);
+ const ModelAction *reader = promise->get_action();
+ CycleNode *node = getNode_noCreate(promise);
+ if (node == NULL) {
+ node = new CycleNode(promise);
+ readerToPromiseNode.put(reader, node);
+ }
+ return node;
+}
- CycleNode *fromnode = getNode(from);
- CycleNode *tonode = getNode(to);
+/**
+ * @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;
+ }
- addEdge(fromnode, tonode);
+ /* 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::addEdge(CycleNode *fromnode, CycleNode *tonode)
+bool CycleGraph::addNodeEdge(CycleNode *fromnode, CycleNode *tonode)
{
+ bool added;
+
if (!hasCycles)
hasCycles = checkReachable(tonode, fromnode);
- if (fromnode->addEdge(tonode))
+ if ((added = fromnode->addEdge(tonode)))
rollbackvector.push_back(fromnode);
/*
if (!hasCycles)
hasCycles = checkReachable(tonode, rmwnode);
- if (rmwnode->addEdge(tonode))
+ if (rmwnode->addEdge(tonode)) {
rollbackvector.push_back(rmwnode);
+ added = true;
+ }
}
+ return added;
}
/**
}
}
- addEdge(fromnode, rmwnode);
+ addNodeEdge(fromnode, rmwnode);
}
#if SUPPORT_MOD_ORDER_DUMP
}
#endif
-/**
- * Checks whether one ModelAction can reach another.
- * @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
-{
- CycleNode *fromnode = actionToNode.get(from);
- CycleNode *tonode = actionToNode.get(to);
-
- if (!fromnode || !tonode)
- return false;
-
- return checkReachable(fromnode, tonode);
-}
-
/**
* Checks whether one CycleNode can reach another.
* @param from The CycleNode from which to begin exploration
return false;
}
+/** @return True, if the promise has failed; false otherwise */
bool CycleGraph::checkPromise(const ModelAction *fromact, Promise *promise) const
{
std::vector< CycleNode *, ModelAlloc<CycleNode *> > queue;
CycleNode *node = queue.back();
queue.pop_back();
- if (promise->eliminate_thread(node->getAction()->get_tid())) {
+ 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);
*/
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)
{
}
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
+ */
+CycleNode * CycleNode::removeEdge()
+{
+ if (edges.empty())
+ return NULL;
+
+ CycleNode *ret = edges.back();
+ edges.pop_back();
+ vector_remove_node(ret->back_edges, this);
+ return ret;
+}
+
+/**
+ * @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 from this CycleNode to another CycleNode.
* @param node The node to which we add a directed edge
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 / c11tester.git / blobdiff