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 promises[i] = PROMISE_UNFULFILLED;
70 * Looks up whether a given promise should be satisfied by this node.
71 * @param i The promise index.
72 * @return true if the promise should be satisfied by the given model action.
74 bool Node::get_promise(unsigned int i) {
75 return (i < promises.size()) && (promises[i] == PROMISE_FULFILLED);
79 * Increments to the next combination of promises.
80 * @return true if we have a valid combination.
82 bool Node::increment_promise() {
83 for (unsigned int i = 0; i < promises.size(); i++) {
84 if (promises[i] == PROMISE_UNFULFILLED) {
85 promises[i] = PROMISE_FULFILLED;
88 if (promises[i] == PROMISE_FULFILLED)
89 promises[i] = PROMISE_UNFULFILLED;
98 * Returns whether the promise set is empty.
99 * @return true if we have explored all promise combinations.
101 bool Node::promise_empty() {
102 for (unsigned int i = 0; i < promises.size();i++)
103 if (promises[i] == PROMISE_UNFULFILLED)
109 * Adds a value from a weakly ordered future write to backtrack to.
110 * @param value is the value to backtrack to.
112 bool Node::add_future_value(uint64_t value) {
113 for (unsigned int i = 0; i < future_values.size(); i++)
114 if (future_values[i] == value)
117 future_values.push_back(value);
122 * Checks whether the future_values set for this node is empty.
123 * @return true if the future_values set is empty.
125 bool Node::future_value_empty() {
126 return ((future_index + 1) >= future_values.size());
130 * Checks if the Thread associated with this thread ID has been explored from
132 * @param tid is the thread ID to check
133 * @return true if this thread choice has been explored already, false
136 bool Node::has_been_explored(thread_id_t tid)
138 int id = id_to_int(tid);
139 return explored_children[id];
143 * Checks if the backtracking set is empty.
144 * @return true if the backtracking set is empty
146 bool Node::backtrack_empty()
148 return (numBacktracks == 0);
152 * Checks whether the readsfrom set for this node is empty.
153 * @return true if the readsfrom set is empty.
155 bool Node::read_from_empty() {
156 return ((read_from_index+1) >= may_read_from.size());
160 * Mark the appropriate backtracking information for exploring a thread choice.
161 * @param act The ModelAction to explore
163 void Node::explore_child(ModelAction *act)
165 explore(act->get_tid());
169 * Records a backtracking reference for a thread choice within this Node.
170 * Provides feedback as to whether this thread choice is already set for
172 * @return false if the thread was already set to be backtracked, true
175 bool Node::set_backtrack(thread_id_t id)
177 int i = id_to_int(id);
185 thread_id_t Node::get_next_backtrack()
187 /** @todo Find next backtrack */
189 for (i = 0; i < backtrack.size(); i++)
190 if (backtrack[i] == true)
192 /* Backtrack set was empty? */
193 ASSERT(i != backtrack.size());
195 backtrack[i] = false;
200 bool Node::is_enabled(Thread *t)
202 return id_to_int(t->get_id()) < num_threads;
206 * Add an action to the may_read_from set.
207 * @param act is the action to add
209 void Node::add_read_from(const ModelAction *act)
211 may_read_from.push_back(act);
215 * Gets the next 'future_value' value from this Node. Only valid for a node
216 * where this->action is a 'read'.
217 * @return The first element in future_values
219 uint64_t Node::get_future_value() {
220 ASSERT(future_index<future_values.size());
221 return future_values[future_index];
224 int Node::get_read_from_size() {
225 return may_read_from.size();
228 const ModelAction * Node::get_read_from_at(int i) {
229 return may_read_from[i];
233 * Gets the next 'may_read_from' action from this Node. Only valid for a node
234 * where this->action is a 'read'.
235 * @return The first element in may_read_from
237 const ModelAction * Node::get_read_from() {
238 if (read_from_index < may_read_from.size())
239 return may_read_from[read_from_index];
245 * Increments the index into the readsfrom set to explore the next item.
246 * @return Returns false if we have explored all items.
248 bool Node::increment_read_from() {
250 return (read_from_index < may_read_from.size());
254 * Increments the index into the future_values set to explore the next item.
255 * @return Returns false if we have explored all values.
257 bool Node::increment_future_value() {
259 return (future_index < future_values.size());
262 void Node::explore(thread_id_t tid)
264 int i = id_to_int(tid);
266 backtrack[i] = false;
269 explored_children[i] = true;
272 static void clear_node_list(node_list_t *list, node_list_t::iterator start,
273 node_list_t::iterator end)
275 node_list_t::iterator it;
277 for (it = start; it != end; it++)
279 list->erase(start, end);
282 NodeStack::NodeStack()
285 node_list.push_back(new Node());
287 iter = node_list.begin();
290 NodeStack::~NodeStack()
292 clear_node_list(&node_list, node_list.begin(), node_list.end());
295 void NodeStack::print()
297 node_list_t::iterator it;
298 printf("............................................\n");
299 printf("NodeStack printing node_list:\n");
300 for (it = node_list.begin(); it != node_list.end(); it++) {
301 if (it == this->iter)
302 printf("vvv following action is the current iterator vvv\n");
305 printf("............................................\n");
308 ModelAction * NodeStack::explore_action(ModelAction *act)
312 ASSERT(!node_list.empty());
313 node_list_t::iterator it=iter;
316 if (it != node_list.end()) {
318 return (*iter)->get_action();
322 get_head()->explore_child(act);
323 node_list.push_back(new Node(act, get_head(), model->get_num_threads()));
330 * Empties the stack of all trailing nodes after a given position and calls the
331 * destructor for each. This function is provided an offset which determines
332 * how many nodes (relative to the current replay state) to save before popping
334 * @param numAhead gives the number of Nodes (including this Node) to skip over
335 * before removing nodes.
337 void NodeStack::pop_restofstack(int numAhead)
339 /* Diverging from previous execution; clear out remainder of list */
340 node_list_t::iterator it = iter;
343 clear_node_list(&node_list, it, node_list.end());
346 Node * NodeStack::get_head()
348 if (node_list.empty())
353 Node * NodeStack::get_next()
355 node_list_t::iterator it = iter;
356 if (node_list.empty()) {
361 if (it == node_list.end()) {
368 void NodeStack::reset_execution()
370 iter = node_list.begin();