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) {
112 if (i >= promises.size())
113 promises.resize(i + 1, PROMISE_IGNORE);
114 if (promises[i] == PROMISE_IGNORE) {
115 promises[i] = PROMISE_UNFULFILLED;
117 promises[i] |= PROMISE_RMW;
122 * Looks up whether a given promise should be satisfied by this node.
123 * @param i The promise index.
124 * @return true if the promise should be satisfied by the given model action.
126 bool Node::get_promise(unsigned int i) const
128 return (i < promises.size()) && ((promises[i] & PROMISE_MASK) == PROMISE_FULFILLED);
132 * Increments to the next combination of promises.
133 * @return true if we have a valid combination.
135 bool Node::increment_promise() {
137 unsigned int rmw_count = 0;
138 for (unsigned int i = 0; i < promises.size(); i++) {
139 if (promises[i] == (PROMISE_RMW|PROMISE_FULFILLED))
143 for (unsigned int i = 0; i < promises.size(); i++) {
144 if ((promises[i] & PROMISE_MASK) == PROMISE_UNFULFILLED) {
145 if ((rmw_count > 0) && (promises[i] & PROMISE_RMW)) {
146 //sending our value to two rmws... not going to work..try next combination
149 promises[i] = (promises[i] & PROMISE_RMW) |PROMISE_FULFILLED;
152 if ((promises[i] & PROMISE_MASK) == PROMISE_FULFILLED)
153 promises[i] = (promises[i] & PROMISE_RMW) | PROMISE_UNFULFILLED;
156 } else if (promises[i] == (PROMISE_RMW|PROMISE_FULFILLED)) {
164 * Returns whether the promise set is empty.
165 * @return true if we have explored all promise combinations.
167 bool Node::promise_empty() const
169 bool fulfilledrmw = false;
170 for (int i = promises.size() - 1; i >= 0; i--) {
171 if (promises[i] == PROMISE_UNFULFILLED)
173 if (!fulfilledrmw && ((promises[i]&PROMISE_MASK) == PROMISE_UNFULFILLED))
175 if (promises[i] == (PROMISE_FULFILLED|PROMISE_RMW))
182 void Node::set_misc_max(int i)
187 int Node::get_misc() const
192 bool Node::increment_misc() {
193 return (misc_index < misc_max) && ((++misc_index) < misc_max);
196 bool Node::misc_empty() const
198 return (misc_index + 1) >= misc_max;
203 * Adds a value from a weakly ordered future write to backtrack to. This
204 * operation may "fail" if the future value has already been run (within some
205 * sloppiness window of this expiration), or if the futurevalues set has
206 * reached its maximum.
207 * @see model_params.maxfuturevalues
209 * @param value is the value to backtrack to.
210 * @return True if the future value was successully added; false otherwise
212 bool Node::add_future_value(uint64_t value, modelclock_t expiration) {
213 int idx = -1; /* Highest index where value is found */
214 for (unsigned int i = 0; i < future_values.size(); i++) {
215 if (future_values[i].value == value) {
216 if (expiration <= future_values[i].expiration)
221 if (idx > future_index) {
222 /* Future value hasn't been explored; update expiration */
223 future_values[idx].expiration = expiration;
225 } else if (idx >= 0 && expiration <= future_values[idx].expiration + model->params.expireslop) {
226 /* Future value has been explored and is within the "sloppy" window */
230 /* Limit the size of the future-values set */
231 if (model->params.maxfuturevalues > 0 &&
232 (int)future_values.size() >= model->params.maxfuturevalues)
235 struct future_value newfv = {value, expiration};
236 future_values.push_back(newfv);
241 * Checks whether the future_values set for this node is empty.
242 * @return true if the future_values set is empty.
244 bool Node::future_value_empty() const
246 return ((future_index + 1) >= ((int)future_values.size()));
250 * Checks if the Thread associated with this thread ID has been explored from
252 * @param tid is the thread ID to check
253 * @return true if this thread choice has been explored already, false
256 bool Node::has_been_explored(thread_id_t tid) const
258 int id = id_to_int(tid);
259 return explored_children[id];
263 * Checks if the backtracking set is empty.
264 * @return true if the backtracking set is empty
266 bool Node::backtrack_empty() const
268 return (numBacktracks == 0);
272 * Checks whether the readsfrom set for this node is empty.
273 * @return true if the readsfrom set is empty.
275 bool Node::read_from_empty() const
277 return ((read_from_index + 1) >= may_read_from.size());
281 * Mark the appropriate backtracking information for exploring a thread choice.
282 * @param act The ModelAction to explore
284 void Node::explore_child(ModelAction *act, enabled_type_t *is_enabled)
287 enabled_array = (enabled_type_t *)model_malloc(sizeof(enabled_type_t) * num_threads);
288 if (is_enabled != NULL)
289 memcpy(enabled_array, is_enabled, sizeof(enabled_type_t) * num_threads);
291 for (int i = 0; i < num_threads; i++)
292 enabled_array[i] = THREAD_DISABLED;
295 explore(act->get_tid());
299 * Records a backtracking reference for a thread choice within this Node.
300 * Provides feedback as to whether this thread choice is already set for
302 * @return false if the thread was already set to be backtracked, true
305 bool Node::set_backtrack(thread_id_t id)
307 int i = id_to_int(id);
308 ASSERT(i < ((int)backtrack.size()));
316 thread_id_t Node::get_next_backtrack()
318 /** @todo Find next backtrack */
320 for (i = 0; i < backtrack.size(); i++)
321 if (backtrack[i] == true)
323 /* Backtrack set was empty? */
324 ASSERT(i != backtrack.size());
326 backtrack[i] = false;
331 bool Node::is_enabled(Thread *t) const
333 int thread_id = id_to_int(t->get_id());
334 return thread_id < num_threads && (enabled_array[thread_id] != THREAD_DISABLED);
337 enabled_type_t Node::enabled_status(thread_id_t tid) const
339 int thread_id = id_to_int(tid);
340 if (thread_id < num_threads)
341 return enabled_array[thread_id];
343 return THREAD_DISABLED;
346 bool Node::is_enabled(thread_id_t tid) const
348 int thread_id = id_to_int(tid);
349 return thread_id < num_threads && (enabled_array[thread_id] != THREAD_DISABLED);
352 bool Node::has_priority(thread_id_t tid) const
354 return fairness[id_to_int(tid)].priority;
358 * Add an action to the may_read_from set.
359 * @param act is the action to add
361 void Node::add_read_from(const ModelAction *act)
363 may_read_from.push_back(act);
367 * Gets the next 'future_value' value from this Node. Only valid for a node
368 * where this->action is a 'read'.
369 * @return The first element in future_values
371 uint64_t Node::get_future_value() const
373 ASSERT(future_index >= 0 && future_index < ((int)future_values.size()));
374 return future_values[future_index].value;
377 modelclock_t Node::get_future_value_expiration() const
379 ASSERT(future_index >= 0 && future_index < ((int)future_values.size()));
380 return future_values[future_index].expiration;
384 int Node::get_read_from_size() const
386 return may_read_from.size();
389 const ModelAction * Node::get_read_from_at(int i) const
391 return may_read_from[i];
395 * Gets the next 'may_read_from' action from this Node. Only valid for a node
396 * where this->action is a 'read'.
397 * @return The first element in may_read_from
399 const ModelAction * Node::get_read_from() const
401 if (read_from_index < may_read_from.size())
402 return may_read_from[read_from_index];
408 * Increments the index into the readsfrom set to explore the next item.
409 * @return Returns false if we have explored all items.
411 bool Node::increment_read_from() {
414 if (read_from_index < may_read_from.size()) {
416 return read_from_index < may_read_from.size();
422 * Increments the index into the future_values set to explore the next item.
423 * @return Returns false if we have explored all values.
425 bool Node::increment_future_value() {
428 if (future_index < ((int)future_values.size())) {
430 return (future_index < ((int)future_values.size()));
436 * Add a write ModelAction to the set of writes that may break the release
437 * sequence. This is used during replay exploration of pending release
438 * sequences. This Node must correspond to a release sequence fixup action.
440 * @param write The write that may break the release sequence. NULL means we
441 * allow the release sequence to synchronize.
443 void Node::add_relseq_break(const ModelAction *write)
445 relseq_break_writes.push_back(write);
449 * Get the write that may break the current pending release sequence,
450 * according to the replay / divergence pattern.
452 * @return A write that may break the release sequence. If NULL, that means
453 * the release sequence should not be broken.
455 const ModelAction * Node::get_relseq_break() const
457 if (relseq_break_index < (int)relseq_break_writes.size())
458 return relseq_break_writes[relseq_break_index];
464 * Increments the index into the relseq_break_writes set to explore the next
466 * @return Returns false if we have explored all values.
468 bool Node::increment_relseq_break()
472 if (relseq_break_index < ((int)relseq_break_writes.size())) {
473 relseq_break_index++;
474 return (relseq_break_index < ((int)relseq_break_writes.size()));
480 * @return True if all writes that may break the release sequence have been
483 bool Node::relseq_break_empty() const
485 return ((relseq_break_index + 1) >= ((int)relseq_break_writes.size()));
488 void Node::explore(thread_id_t tid)
490 int i = id_to_int(tid);
491 ASSERT(i < ((int)backtrack.size()));
493 backtrack[i] = false;
496 explored_children[i] = true;
499 NodeStack::NodeStack() :
507 NodeStack::~NodeStack()
509 for (unsigned int i = 0; i < node_list.size(); i++)
513 void NodeStack::print() const
515 model_print("............................................\n");
516 model_print("NodeStack printing node_list:\n");
517 for (unsigned int it = 0; it < node_list.size(); it++) {
518 if ((int)it == this->head_idx)
519 model_print("vvv following action is the current iterator vvv\n");
520 node_list[it]->print();
522 model_print("............................................\n");
525 /** Note: The is_enabled set contains what actions were enabled when
527 ModelAction * NodeStack::explore_action(ModelAction *act, enabled_type_t *is_enabled)
531 if ((head_idx + 1) < (int)node_list.size()) {
533 return node_list[head_idx]->get_action();
537 Node *head = get_head();
538 Node *prevfairness = NULL;
540 head->explore_child(act, is_enabled);
541 if (model->params.fairwindow != 0 && head_idx > (int)model->params.fairwindow)
542 prevfairness = node_list[head_idx - model->params.fairwindow];
544 node_list.push_back(new Node(act, head, model->get_num_threads(), prevfairness));
551 * Empties the stack of all trailing nodes after a given position and calls the
552 * destructor for each. This function is provided an offset which determines
553 * how many nodes (relative to the current replay state) to save before popping
555 * @param numAhead gives the number of Nodes (including this Node) to skip over
556 * before removing nodes.
558 void NodeStack::pop_restofstack(int numAhead)
560 /* Diverging from previous execution; clear out remainder of list */
561 unsigned int it = head_idx + numAhead;
562 for (unsigned int i = it; i < node_list.size(); i++)
564 node_list.resize(it);
567 Node * NodeStack::get_head() const
569 if (node_list.empty() || head_idx < 0)
571 return node_list[head_idx];
574 Node * NodeStack::get_next() const
576 if (node_list.empty()) {
580 unsigned int it = head_idx + 1;
581 if (it == node_list.size()) {
585 return node_list[it];
588 void NodeStack::reset_execution()