7 #include "threads-model.h"
10 * @brief Node constructor
12 * Constructs a single Node for use in a NodeStack. Each Node is associated
13 * with exactly one ModelAction (exception: the first Node should be created
14 * as an empty stub, to represent the first thread "choice") and up to one
17 * @param act The ModelAction to associate with this Node. May be NULL.
18 * @param par The parent Node in the NodeStack. May be NULL if there is no
20 * @param nthreads The number of threads which exist at this point in the
23 Node::Node(ModelAction *act, Node *par, int nthreads, Node *prevfairness)
26 num_threads(nthreads),
27 explored_children(num_threads),
28 backtrack(num_threads),
29 fairness(num_threads),
36 relseq_break_writes(),
37 relseq_break_index(0),
43 int currtid = id_to_int(act->get_tid());
44 int prevtid = (prevfairness != NULL) ? id_to_int(prevfairness->action->get_tid()) : 0;
46 if (model->params.fairwindow != 0) {
47 for (int i = 0; i < nthreads; i++) {
48 ASSERT(i < ((int)fairness.size()));
49 struct fairness_info *fi = &fairness[i];
50 struct fairness_info *prevfi = (par != NULL) && (i < par->get_num_threads()) ? &par->fairness[i] : NULL;
54 if (parent && parent->is_enabled(int_to_id(i))) {
61 /* Do window processing */
62 if (prevfairness != NULL) {
63 if (prevfairness->parent->is_enabled(int_to_id(i)))
68 /* Need full window to start evaluating
70 * If we meet the enabled count and have no
71 * turns, give us priority */
72 if ((fi->enabled_count >= model->params.enabledcount) &&
80 /** @brief Node desctructor */
85 model_free(enabled_array);
88 /** Prints debugging info for the ModelAction associated with this Node */
92 model_print(" backtrack: %s\n", backtrack_empty() ? "empty" : "non-empty");
93 model_print(" future values: %s\n", future_value_empty() ? "empty" : "non-empty");
94 model_print(" read-from: %s\n", read_from_empty() ? "empty" : "non-empty");
95 model_print(" promises: %s\n", promise_empty() ? "empty" : "non-empty");
96 model_print(" misc: %s\n", misc_empty() ? "empty" : "non-empty");
97 model_print(" rel seq break: %s\n", relseq_break_empty() ? "empty" : "non-empty");
100 /** @brief Prints info about may_read_from set */
101 void Node::print_may_read_from()
103 for (unsigned int i = 0; i < may_read_from.size(); i++)
104 may_read_from[i]->print();
108 * Sets a promise to explore meeting with the given node.
109 * @param i is the promise index.
111 void Node::set_promise(unsigned int i, bool is_rmw)
113 if (i >= promises.size())
114 promises.resize(i + 1, PROMISE_IGNORE);
115 if (promises[i] == PROMISE_IGNORE) {
116 promises[i] = PROMISE_UNFULFILLED;
118 promises[i] |= PROMISE_RMW;
123 * Looks up whether a given promise should be satisfied by this node.
124 * @param i The promise index.
125 * @return true if the promise should be satisfied by the given model action.
127 bool Node::get_promise(unsigned int i) const
129 return (i < promises.size()) && ((promises[i] & PROMISE_MASK) == PROMISE_FULFILLED);
133 * Increments to the next combination of promises.
134 * @return true if we have a valid combination.
136 bool Node::increment_promise()
139 unsigned int rmw_count = 0;
140 for (unsigned int i = 0; i < promises.size(); i++) {
141 if (promises[i] == (PROMISE_RMW|PROMISE_FULFILLED))
145 for (unsigned int i = 0; i < promises.size(); i++) {
146 if ((promises[i] & PROMISE_MASK) == PROMISE_UNFULFILLED) {
147 if ((rmw_count > 0) && (promises[i] & PROMISE_RMW)) {
148 //sending our value to two rmws... not going to work..try next combination
151 promises[i] = (promises[i] & PROMISE_RMW) |PROMISE_FULFILLED;
154 if ((promises[i] & PROMISE_MASK) == PROMISE_FULFILLED)
155 promises[i] = (promises[i] & PROMISE_RMW) | PROMISE_UNFULFILLED;
158 } else if (promises[i] == (PROMISE_RMW|PROMISE_FULFILLED)) {
166 * Returns whether the promise set is empty.
167 * @return true if we have explored all promise combinations.
169 bool Node::promise_empty() const
171 bool fulfilledrmw = false;
172 for (int i = promises.size() - 1; i >= 0; i--) {
173 if (promises[i] == PROMISE_UNFULFILLED)
175 if (!fulfilledrmw && ((promises[i]&PROMISE_MASK) == PROMISE_UNFULFILLED))
177 if (promises[i] == (PROMISE_FULFILLED|PROMISE_RMW))
184 void Node::set_misc_max(int i)
189 int Node::get_misc() const
194 bool Node::increment_misc()
196 return (misc_index < misc_max) && ((++misc_index) < misc_max);
199 bool Node::misc_empty() const
201 return (misc_index + 1) >= misc_max;
206 * Adds a value from a weakly ordered future write to backtrack to. This
207 * operation may "fail" if the future value has already been run (within some
208 * sloppiness window of this expiration), or if the futurevalues set has
209 * reached its maximum.
210 * @see model_params.maxfuturevalues
212 * @param value is the value to backtrack to.
213 * @return True if the future value was successully added; false otherwise
215 bool Node::add_future_value(uint64_t value, modelclock_t expiration)
217 int idx = -1; /* Highest index where value is found */
218 for (unsigned int i = 0; i < future_values.size(); i++) {
219 if (future_values[i].value == value) {
220 if (expiration <= future_values[i].expiration)
225 if (idx > future_index) {
226 /* Future value hasn't been explored; update expiration */
227 future_values[idx].expiration = expiration;
229 } else if (idx >= 0 && expiration <= future_values[idx].expiration + model->params.expireslop) {
230 /* Future value has been explored and is within the "sloppy" window */
234 /* Limit the size of the future-values set */
235 if (model->params.maxfuturevalues > 0 &&
236 (int)future_values.size() >= model->params.maxfuturevalues)
239 struct future_value newfv = {value, expiration};
240 future_values.push_back(newfv);
245 * Checks whether the future_values set for this node is empty.
246 * @return true if the future_values set is empty.
248 bool Node::future_value_empty() const
250 return ((future_index + 1) >= ((int)future_values.size()));
254 * Checks if the Thread associated with this thread ID has been explored from
256 * @param tid is the thread ID to check
257 * @return true if this thread choice has been explored already, false
260 bool Node::has_been_explored(thread_id_t tid) const
262 int id = id_to_int(tid);
263 return explored_children[id];
267 * Checks if the backtracking set is empty.
268 * @return true if the backtracking set is empty
270 bool Node::backtrack_empty() const
272 return (numBacktracks == 0);
276 * Checks whether the readsfrom set for this node is empty.
277 * @return true if the readsfrom set is empty.
279 bool Node::read_from_empty() const
281 return ((read_from_index + 1) >= may_read_from.size());
285 * Mark the appropriate backtracking information for exploring a thread choice.
286 * @param act The ModelAction to explore
288 void Node::explore_child(ModelAction *act, enabled_type_t *is_enabled)
291 enabled_array = (enabled_type_t *)model_malloc(sizeof(enabled_type_t) * num_threads);
292 if (is_enabled != NULL)
293 memcpy(enabled_array, is_enabled, sizeof(enabled_type_t) * num_threads);
295 for (int i = 0; i < num_threads; i++)
296 enabled_array[i] = THREAD_DISABLED;
299 explore(act->get_tid());
303 * Records a backtracking reference for a thread choice within this Node.
304 * Provides feedback as to whether this thread choice is already set for
306 * @return false if the thread was already set to be backtracked, true
309 bool Node::set_backtrack(thread_id_t id)
311 int i = id_to_int(id);
312 ASSERT(i < ((int)backtrack.size()));
320 thread_id_t Node::get_next_backtrack()
322 /** @todo Find next backtrack */
324 for (i = 0; i < backtrack.size(); i++)
325 if (backtrack[i] == true)
327 /* Backtrack set was empty? */
328 ASSERT(i != backtrack.size());
330 backtrack[i] = false;
335 bool Node::is_enabled(Thread *t) const
337 int thread_id = id_to_int(t->get_id());
338 return thread_id < num_threads && (enabled_array[thread_id] != THREAD_DISABLED);
341 enabled_type_t Node::enabled_status(thread_id_t tid) const
343 int thread_id = id_to_int(tid);
344 if (thread_id < num_threads)
345 return enabled_array[thread_id];
347 return THREAD_DISABLED;
350 bool Node::is_enabled(thread_id_t tid) const
352 int thread_id = id_to_int(tid);
353 return thread_id < num_threads && (enabled_array[thread_id] != THREAD_DISABLED);
356 bool Node::has_priority(thread_id_t tid) const
358 return fairness[id_to_int(tid)].priority;
362 * Add an action to the may_read_from set.
363 * @param act is the action to add
365 void Node::add_read_from(const ModelAction *act)
367 may_read_from.push_back(act);
371 * Gets the next 'future_value' value from this Node. Only valid for a node
372 * where this->action is a 'read'.
373 * @return The first element in future_values
375 uint64_t Node::get_future_value() const
377 ASSERT(future_index >= 0 && future_index < ((int)future_values.size()));
378 return future_values[future_index].value;
381 modelclock_t Node::get_future_value_expiration() const
383 ASSERT(future_index >= 0 && future_index < ((int)future_values.size()));
384 return future_values[future_index].expiration;
388 int Node::get_read_from_size() const
390 return may_read_from.size();
393 const ModelAction * Node::get_read_from_at(int i) const
395 return may_read_from[i];
399 * Gets the next 'may_read_from' action from this Node. Only valid for a node
400 * where this->action is a 'read'.
401 * @return The first element in may_read_from
403 const ModelAction * Node::get_read_from() const
405 if (read_from_index < may_read_from.size())
406 return may_read_from[read_from_index];
412 * Increments the index into the readsfrom set to explore the next item.
413 * @return Returns false if we have explored all items.
415 bool Node::increment_read_from()
419 if (read_from_index < may_read_from.size()) {
421 return read_from_index < may_read_from.size();
427 * Increments the index into the future_values set to explore the next item.
428 * @return Returns false if we have explored all values.
430 bool Node::increment_future_value()
434 if (future_index < ((int)future_values.size())) {
436 return (future_index < ((int)future_values.size()));
442 * Add a write ModelAction to the set of writes that may break the release
443 * sequence. This is used during replay exploration of pending release
444 * sequences. This Node must correspond to a release sequence fixup action.
446 * @param write The write that may break the release sequence. NULL means we
447 * allow the release sequence to synchronize.
449 void Node::add_relseq_break(const ModelAction *write)
451 relseq_break_writes.push_back(write);
455 * Get the write that may break the current pending release sequence,
456 * according to the replay / divergence pattern.
458 * @return A write that may break the release sequence. If NULL, that means
459 * the release sequence should not be broken.
461 const ModelAction * Node::get_relseq_break() const
463 if (relseq_break_index < (int)relseq_break_writes.size())
464 return relseq_break_writes[relseq_break_index];
470 * Increments the index into the relseq_break_writes set to explore the next
472 * @return Returns false if we have explored all values.
474 bool Node::increment_relseq_break()
478 if (relseq_break_index < ((int)relseq_break_writes.size())) {
479 relseq_break_index++;
480 return (relseq_break_index < ((int)relseq_break_writes.size()));
486 * @return True if all writes that may break the release sequence have been
489 bool Node::relseq_break_empty() const
491 return ((relseq_break_index + 1) >= ((int)relseq_break_writes.size()));
494 void Node::explore(thread_id_t tid)
496 int i = id_to_int(tid);
497 ASSERT(i < ((int)backtrack.size()));
499 backtrack[i] = false;
502 explored_children[i] = true;
505 NodeStack::NodeStack() :
513 NodeStack::~NodeStack()
515 for (unsigned int i = 0; i < node_list.size(); i++)
519 void NodeStack::print() const
521 model_print("............................................\n");
522 model_print("NodeStack printing node_list:\n");
523 for (unsigned int it = 0; it < node_list.size(); it++) {
524 if ((int)it == this->head_idx)
525 model_print("vvv following action is the current iterator vvv\n");
526 node_list[it]->print();
528 model_print("............................................\n");
531 /** Note: The is_enabled set contains what actions were enabled when
533 ModelAction * NodeStack::explore_action(ModelAction *act, enabled_type_t *is_enabled)
537 if ((head_idx + 1) < (int)node_list.size()) {
539 return node_list[head_idx]->get_action();
543 Node *head = get_head();
544 Node *prevfairness = NULL;
546 head->explore_child(act, is_enabled);
547 if (model->params.fairwindow != 0 && head_idx > (int)model->params.fairwindow)
548 prevfairness = node_list[head_idx - model->params.fairwindow];
550 node_list.push_back(new Node(act, head, model->get_num_threads(), prevfairness));
557 * Empties the stack of all trailing nodes after a given position and calls the
558 * destructor for each. This function is provided an offset which determines
559 * how many nodes (relative to the current replay state) to save before popping
561 * @param numAhead gives the number of Nodes (including this Node) to skip over
562 * before removing nodes.
564 void NodeStack::pop_restofstack(int numAhead)
566 /* Diverging from previous execution; clear out remainder of list */
567 unsigned int it = head_idx + numAhead;
568 for (unsigned int i = it; i < node_list.size(); i++)
570 node_list.resize(it);
573 Node * NodeStack::get_head() const
575 if (node_list.empty() || head_idx < 0)
577 return node_list[head_idx];
580 Node * NodeStack::get_next() const
582 if (node_list.empty()) {
586 unsigned int it = head_idx + 1;
587 if (it == node_list.size()) {
591 return node_list[it];
594 void NodeStack::reset_execution()