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->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 conditions
69 //If we meet the enabled count and have no turns, give us priority
70 if ((fi->enabled_count >= model->params.enabledcount) &&
79 /** @brief Node desctructor */
85 model_free(enabled_array);
88 /** Prints debugging info for the ModelAction associated with this Node */
94 printf("******** empty action ********\n");
97 /** @brief Prints info about may_read_from set */
98 void Node::print_may_read_from()
100 for (unsigned int i = 0; i < may_read_from.size(); i++)
101 may_read_from[i]->print();
105 * Sets a promise to explore meeting with the given node.
106 * @param i is the promise index.
108 void Node::set_promise(unsigned int i, bool is_rmw) {
109 if (i >= promises.size())
110 promises.resize(i + 1, PROMISE_IGNORE);
111 if (promises[i] == PROMISE_IGNORE) {
112 promises[i] = PROMISE_UNFULFILLED;
114 promises[i] |= PROMISE_RMW;
119 * Looks up whether a given promise should be satisfied by this node.
120 * @param i The promise index.
121 * @return true if the promise should be satisfied by the given model action.
123 bool Node::get_promise(unsigned int i) {
124 return (i < promises.size()) && ((promises[i] & PROMISE_MASK) == PROMISE_FULFILLED);
128 * Increments to the next combination of promises.
129 * @return true if we have a valid combination.
131 bool Node::increment_promise() {
133 unsigned int rmw_count=0;
134 for (unsigned int i = 0; i < promises.size(); i++) {
135 if (promises[i]==(PROMISE_RMW|PROMISE_FULFILLED))
139 for (unsigned int i = 0; i < promises.size(); i++) {
140 if ((promises[i] & PROMISE_MASK) == PROMISE_UNFULFILLED) {
141 if ((rmw_count > 0) && (promises[i] & PROMISE_RMW)) {
142 //sending our value to two rmws... not going to work..try next combination
145 promises[i] = (promises[i] & PROMISE_RMW) |PROMISE_FULFILLED;
148 if ((promises[i] & PROMISE_MASK) == PROMISE_FULFILLED)
149 promises[i] = (promises[i] & PROMISE_RMW) | PROMISE_UNFULFILLED;
152 } else if (promises[i] == (PROMISE_RMW|PROMISE_FULFILLED)) {
160 * Returns whether the promise set is empty.
161 * @return true if we have explored all promise combinations.
163 bool Node::promise_empty() {
164 bool fulfilledrmw=false;
165 for (int i = promises.size()-1 ; i>=0; i--) {
166 if (promises[i]==PROMISE_UNFULFILLED)
168 if (!fulfilledrmw && ((promises[i]&PROMISE_MASK)==PROMISE_UNFULFILLED))
170 if (promises[i]==(PROMISE_FULFILLED|PROMISE_RMW))
177 void Node::set_misc_max(int i) {
181 int Node::get_misc() {
185 bool Node::increment_misc() {
186 return (misc_index<misc_max)&&((++misc_index)<misc_max);
189 bool Node::misc_empty() {
190 return (misc_index+1)>=misc_max;
195 * Adds a value from a weakly ordered future write to backtrack to. This
196 * operation may "fail" if the future value has already been run (within some
197 * sloppiness window of this expiration), or if the futurevalues set has
198 * reached its maximum.
199 * @see model_params.maxfuturevalues
201 * @param value is the value to backtrack to.
202 * @return True if the future value was successully added; false otherwise
204 bool Node::add_future_value(uint64_t value, modelclock_t expiration) {
205 int idx = -1; /* Highest index where value is found */
206 for (unsigned int i = 0; i < future_values.size(); i++) {
207 if (future_values[i].value == value) {
208 if (expiration <= future_values[i].expiration)
213 if (idx > future_index) {
214 /* Future value hasn't been explored; update expiration */
215 future_values[idx].expiration = expiration;
217 } else if (idx >= 0 && expiration <= future_values[idx].expiration + model->params.expireslop) {
218 /* Future value has been explored and is within the "sloppy" window */
222 /* Limit the size of the future-values set */
223 if (model->params.maxfuturevalues > 0 &&
224 (int)future_values.size() >= model->params.maxfuturevalues)
227 struct future_value newfv = {value, expiration};
228 future_values.push_back(newfv);
233 * Checks whether the future_values set for this node is empty.
234 * @return true if the future_values set is empty.
236 bool Node::future_value_empty() {
237 return ((future_index + 1) >= ((int)future_values.size()));
241 * Checks if the Thread associated with this thread ID has been explored from
243 * @param tid is the thread ID to check
244 * @return true if this thread choice has been explored already, false
247 bool Node::has_been_explored(thread_id_t tid)
249 int id = id_to_int(tid);
250 return explored_children[id];
254 * Checks if the backtracking set is empty.
255 * @return true if the backtracking set is empty
257 bool Node::backtrack_empty()
259 return (numBacktracks == 0);
263 * Checks whether the readsfrom set for this node is empty.
264 * @return true if the readsfrom set is empty.
266 bool Node::read_from_empty() {
267 return ((read_from_index+1) >= may_read_from.size());
271 * Mark the appropriate backtracking information for exploring a thread choice.
272 * @param act The ModelAction to explore
274 void Node::explore_child(ModelAction *act, enabled_type_t * is_enabled)
276 if ( ! enabled_array )
277 enabled_array=(enabled_type_t *)model_malloc(sizeof(enabled_type_t)*num_threads);
278 if (is_enabled != NULL)
279 memcpy(enabled_array, is_enabled, sizeof(enabled_type_t)*num_threads);
281 for(int i=0;i<num_threads;i++)
282 enabled_array[i]=THREAD_DISABLED;
285 explore(act->get_tid());
289 * Records a backtracking reference for a thread choice within this Node.
290 * Provides feedback as to whether this thread choice is already set for
292 * @return false if the thread was already set to be backtracked, true
295 bool Node::set_backtrack(thread_id_t id)
297 int i = id_to_int(id);
298 ASSERT(i<((int)backtrack.size()));
306 thread_id_t Node::get_next_backtrack()
308 /** @todo Find next backtrack */
310 for (i = 0; i < backtrack.size(); i++)
311 if (backtrack[i] == true)
313 /* Backtrack set was empty? */
314 ASSERT(i != backtrack.size());
316 backtrack[i] = false;
321 bool Node::is_enabled(Thread *t)
323 int thread_id=id_to_int(t->get_id());
324 return thread_id < num_threads && (enabled_array[thread_id] != THREAD_DISABLED);
327 enabled_type_t Node::enabled_status(thread_id_t tid) {
328 int thread_id=id_to_int(tid);
329 if (thread_id < num_threads)
330 return enabled_array[thread_id];
332 return THREAD_DISABLED;
335 bool Node::is_enabled(thread_id_t tid)
337 int thread_id=id_to_int(tid);
338 return thread_id < num_threads && (enabled_array[thread_id] != THREAD_DISABLED);
341 bool Node::has_priority(thread_id_t tid)
343 return fairness[id_to_int(tid)].priority;
347 * Add an action to the may_read_from set.
348 * @param act is the action to add
350 void Node::add_read_from(const ModelAction *act)
352 may_read_from.push_back(act);
356 * Gets the next 'future_value' value from this Node. Only valid for a node
357 * where this->action is a 'read'.
358 * @return The first element in future_values
360 uint64_t Node::get_future_value() {
361 ASSERT(future_index >= 0 && future_index<((int)future_values.size()));
362 return future_values[future_index].value;
365 modelclock_t Node::get_future_value_expiration() {
366 ASSERT(future_index >= 0 && future_index<((int)future_values.size()));
367 return future_values[future_index].expiration;
371 int Node::get_read_from_size() {
372 return may_read_from.size();
375 const ModelAction * Node::get_read_from_at(int i) {
376 return may_read_from[i];
380 * Gets the next 'may_read_from' action from this Node. Only valid for a node
381 * where this->action is a 'read'.
382 * @return The first element in may_read_from
384 const ModelAction * Node::get_read_from() {
385 if (read_from_index < may_read_from.size())
386 return may_read_from[read_from_index];
392 * Increments the index into the readsfrom set to explore the next item.
393 * @return Returns false if we have explored all items.
395 bool Node::increment_read_from() {
398 if (read_from_index < may_read_from.size()) {
400 return read_from_index < may_read_from.size();
406 * Increments the index into the future_values set to explore the next item.
407 * @return Returns false if we have explored all values.
409 bool Node::increment_future_value() {
412 if (future_index < ((int)future_values.size())) {
414 return (future_index < ((int)future_values.size()));
420 * Add a write ModelAction to the set of writes that may break the release
421 * sequence. This is used during replay exploration of pending release
422 * sequences. This Node must correspond to a release sequence fixup action.
424 * @param write The write that may break the release sequence. NULL means we
425 * allow the release sequence to synchronize.
427 void Node::add_relseq_break(const ModelAction *write)
429 relseq_break_writes.push_back(write);
433 * Get the write that may break the current pending release sequence,
434 * according to the replay / divergence pattern.
436 * @return A write that may break the release sequence. If NULL, that means
437 * the release sequence should not be broken.
439 const ModelAction * Node::get_relseq_break()
441 if (relseq_break_index < (int)relseq_break_writes.size())
442 return relseq_break_writes[relseq_break_index];
448 * Increments the index into the relseq_break_writes set to explore the next
450 * @return Returns false if we have explored all values.
452 bool Node::increment_relseq_break()
456 if (relseq_break_index < ((int)relseq_break_writes.size())) {
457 relseq_break_index++;
458 return (relseq_break_index < ((int)relseq_break_writes.size()));
464 * @return True if all writes that may break the release sequence have been
467 bool Node::relseq_break_empty() {
468 return ((relseq_break_index + 1) >= ((int)relseq_break_writes.size()));
471 void Node::explore(thread_id_t tid)
473 int i = id_to_int(tid);
474 ASSERT(i<((int)backtrack.size()));
476 backtrack[i] = false;
479 explored_children[i] = true;
482 NodeStack::NodeStack() :
483 node_list(1, new Node()),
490 NodeStack::~NodeStack()
492 for (unsigned int i = 0; i < node_list.size(); i++)
496 void NodeStack::print()
498 printf("............................................\n");
499 printf("NodeStack printing node_list:\n");
500 for (unsigned int it = 0; it < node_list.size(); it++) {
501 if (it == this->iter)
502 printf("vvv following action is the current iterator vvv\n");
503 node_list[it]->print();
505 printf("............................................\n");
508 /** Note: The is_enabled set contains what actions were enabled when
511 ModelAction * NodeStack::explore_action(ModelAction *act, enabled_type_t * is_enabled)
515 ASSERT(!node_list.empty());
517 if ((iter+1) < node_list.size()) {
519 return node_list[iter]->get_action();
523 get_head()->explore_child(act, is_enabled);
524 Node *prevfairness = NULL;
525 if ( model->params.fairwindow != 0 && iter > model->params.fairwindow ) {
526 prevfairness = node_list[iter-model->params.fairwindow];
528 node_list.push_back(new Node(act, get_head(), model->get_num_threads(), prevfairness));
535 * Empties the stack of all trailing nodes after a given position and calls the
536 * destructor for each. This function is provided an offset which determines
537 * how many nodes (relative to the current replay state) to save before popping
539 * @param numAhead gives the number of Nodes (including this Node) to skip over
540 * before removing nodes.
542 void NodeStack::pop_restofstack(int numAhead)
544 /* Diverging from previous execution; clear out remainder of list */
545 unsigned int it=iter+numAhead;
546 for(unsigned int i=it;i<node_list.size();i++)
548 node_list.resize(it);
551 Node * NodeStack::get_head()
553 if (node_list.empty())
555 return node_list[iter];
558 Node * NodeStack::get_next()
560 if (node_list.empty()) {
564 unsigned int it=iter+1;
565 if (it == node_list.size()) {
569 return node_list[it];
572 void NodeStack::reset_execution()