7 * @brief Node constructor
9 * Constructs a single Node for use in a NodeStack. Each Node is associated
10 * with exactly one ModelAction (exception: the first Node should be created
11 * as an empty stub, to represent the first thread "choice") and up to one
14 * @param act The ModelAction to associate with this Node. May be NULL.
15 * @param par The parent Node in the NodeStack. May be NULL if there is no
17 * @param nthreads The number of threads which exist at this point in the
20 Node::Node(ModelAction *act, Node *par, int nthreads)
23 num_threads(nthreads),
24 explored_children(num_threads),
25 backtrack(num_threads),
36 /** @brief Node desctructor */
43 /** Prints debugging info for the ModelAction associated with this Node */
49 printf("******** empty action ********\n");
52 /** @brief Prints info about may_read_from set */
53 void Node::print_may_read_from()
55 for (unsigned int i = 0; i < may_read_from.size(); i++)
56 may_read_from[i]->print();
60 * Sets a promise to explore meeting with the given node.
61 * @param i is the promise index.
63 void Node::set_promise(unsigned int i) {
64 if (i >= promises.size())
65 promises.resize(i + 1, PROMISE_IGNORE);
66 if (promises[i] == PROMISE_IGNORE)
67 promises[i] = PROMISE_UNFULFILLED;
71 * Looks up whether a given promise should be satisfied by this node.
72 * @param i The promise index.
73 * @return true if the promise should be satisfied by the given model action.
75 bool Node::get_promise(unsigned int i) {
76 return (i < promises.size()) && (promises[i] == PROMISE_FULFILLED);
80 * Increments to the next combination of promises.
81 * @return true if we have a valid combination.
83 bool Node::increment_promise() {
84 for (unsigned int i = 0; i < promises.size(); i++) {
85 if (promises[i] == PROMISE_UNFULFILLED) {
86 promises[i] = PROMISE_FULFILLED;
89 if (promises[i] == PROMISE_FULFILLED)
90 promises[i] = PROMISE_UNFULFILLED;
99 * Returns whether the promise set is empty.
100 * @return true if we have explored all promise combinations.
102 bool Node::promise_empty() {
103 for (unsigned int i = 0; i < promises.size();i++)
104 if (promises[i] == PROMISE_UNFULFILLED)
110 * Adds a value from a weakly ordered future write to backtrack to.
111 * @param value is the value to backtrack to.
113 bool Node::add_future_value(uint64_t value, modelclock_t expiration) {
114 int suitableindex=-1;
115 for (unsigned int i = 0; i < future_values.size(); i++) {
116 if (future_values[i].value == value) {
117 if (future_values[i].expiration>=expiration)
119 if (future_index < i) {
125 if (suitableindex!=-1) {
126 future_values[suitableindex].expiration=expiration;
129 struct future_value newfv={value, expiration};
130 future_values.push_back(newfv);
135 * Checks whether the future_values set for this node is empty.
136 * @return true if the future_values set is empty.
138 bool Node::future_value_empty() {
139 return ((future_index + 1) >= future_values.size());
143 * Checks if the Thread associated with this thread ID has been explored from
145 * @param tid is the thread ID to check
146 * @return true if this thread choice has been explored already, false
149 bool Node::has_been_explored(thread_id_t tid)
151 int id = id_to_int(tid);
152 return explored_children[id];
156 * Checks if the backtracking set is empty.
157 * @return true if the backtracking set is empty
159 bool Node::backtrack_empty()
161 return (numBacktracks == 0);
165 * Checks whether the readsfrom set for this node is empty.
166 * @return true if the readsfrom set is empty.
168 bool Node::read_from_empty() {
169 return ((read_from_index+1) >= may_read_from.size());
173 * Mark the appropriate backtracking information for exploring a thread choice.
174 * @param act The ModelAction to explore
176 void Node::explore_child(ModelAction *act)
178 explore(act->get_tid());
182 * Records a backtracking reference for a thread choice within this Node.
183 * Provides feedback as to whether this thread choice is already set for
185 * @return false if the thread was already set to be backtracked, true
188 bool Node::set_backtrack(thread_id_t id)
190 int i = id_to_int(id);
198 thread_id_t Node::get_next_backtrack()
200 /** @todo Find next backtrack */
202 for (i = 0; i < backtrack.size(); i++)
203 if (backtrack[i] == true)
205 /* Backtrack set was empty? */
206 ASSERT(i != backtrack.size());
208 backtrack[i] = false;
213 bool Node::is_enabled(Thread *t)
215 return id_to_int(t->get_id()) < num_threads;
219 * Add an action to the may_read_from set.
220 * @param act is the action to add
222 void Node::add_read_from(const ModelAction *act)
224 may_read_from.push_back(act);
228 * Gets the next 'future_value' value from this Node. Only valid for a node
229 * where this->action is a 'read'.
230 * @return The first element in future_values
232 uint64_t Node::get_future_value() {
233 ASSERT(future_index<future_values.size());
234 return future_values[future_index].value;
237 modelclock_t Node::get_future_value_expiration() {
238 ASSERT(future_index<future_values.size());
239 return future_values[future_index].expiration;
243 int Node::get_read_from_size() {
244 return may_read_from.size();
247 const ModelAction * Node::get_read_from_at(int i) {
248 return may_read_from[i];
252 * Gets the next 'may_read_from' action from this Node. Only valid for a node
253 * where this->action is a 'read'.
254 * @return The first element in may_read_from
256 const ModelAction * Node::get_read_from() {
257 if (read_from_index < may_read_from.size())
258 return may_read_from[read_from_index];
264 * Increments the index into the readsfrom set to explore the next item.
265 * @return Returns false if we have explored all items.
267 bool Node::increment_read_from() {
269 return (read_from_index < may_read_from.size());
273 * Increments the index into the future_values set to explore the next item.
274 * @return Returns false if we have explored all values.
276 bool Node::increment_future_value() {
278 return (future_index < future_values.size());
281 void Node::explore(thread_id_t tid)
283 int i = id_to_int(tid);
285 backtrack[i] = false;
288 explored_children[i] = true;
291 static void clear_node_list(node_list_t *list, node_list_t::iterator start,
292 node_list_t::iterator end)
294 node_list_t::iterator it;
296 for (it = start; it != end; it++)
298 list->erase(start, end);
301 NodeStack::NodeStack()
304 node_list.push_back(new Node());
306 iter = node_list.begin();
309 NodeStack::~NodeStack()
311 clear_node_list(&node_list, node_list.begin(), node_list.end());
314 void NodeStack::print()
316 node_list_t::iterator it;
317 printf("............................................\n");
318 printf("NodeStack printing node_list:\n");
319 for (it = node_list.begin(); it != node_list.end(); it++) {
320 if (it == this->iter)
321 printf("vvv following action is the current iterator vvv\n");
324 printf("............................................\n");
327 ModelAction * NodeStack::explore_action(ModelAction *act)
331 ASSERT(!node_list.empty());
332 node_list_t::iterator it=iter;
335 if (it != node_list.end()) {
337 return (*iter)->get_action();
341 get_head()->explore_child(act);
342 node_list.push_back(new Node(act, get_head(), model->get_num_threads()));
349 * Empties the stack of all trailing nodes after a given position and calls the
350 * destructor for each. This function is provided an offset which determines
351 * how many nodes (relative to the current replay state) to save before popping
353 * @param numAhead gives the number of Nodes (including this Node) to skip over
354 * before removing nodes.
356 void NodeStack::pop_restofstack(int numAhead)
358 /* Diverging from previous execution; clear out remainder of list */
359 node_list_t::iterator it = iter;
362 clear_node_list(&node_list, it, node_list.end());
365 Node * NodeStack::get_head()
367 if (node_list.empty())
372 Node * NodeStack::get_next()
374 node_list_t::iterator it = iter;
375 if (node_list.empty()) {
380 if (it == node_list.end()) {
387 void NodeStack::reset_execution()
389 iter = node_list.begin();