/* The next node will read from a different value. */
tid = next->get_tid();
node_stack->pop_restofstack(2);
- } else if (nextnode->increment_future_value()) {
- /* The next node will try to read from a different future value. */
- tid = next->get_tid();
- node_stack->pop_restofstack(2);
} else if (nextnode->increment_relseq_break()) {
/* The next node will try to resolve a release sequence differently */
tid = next->get_tid();
earliest_diverge = prevnode->get_action();
}
}
+ /* Start the round robin scheduler from this thread id */
+ scheduler->set_scheduler_thread(tid);
/* The correct sleep set is in the parent node. */
execute_sleep_set();
return blocking_threads;
}
+/**
+ * Check if a Thread has entered a circular wait deadlock situation. This will
+ * not check other threads for potential deadlock situations, and may miss
+ * deadlocks involving WAIT.
+ *
+ * @param t The thread which may have entered a deadlock
+ * @return True if this Thread entered a deadlock; false otherwise
+ */
+bool ModelChecker::is_circular_wait(const Thread *t) const
+{
+ for (Thread *waiting = t->waiting_on() ; waiting != NULL; waiting = waiting->waiting_on())
+ if (waiting == t)
+ return true;
+ return false;
+}
+
/**
* Check if this is a complete execution. That is, have all thread completed
* execution (rather than exiting because sleep sets have forced a redundant
stats.num_buggy_executions++;
else if (is_complete_execution())
stats.num_complete++;
- else
+ else {
stats.num_redundant++;
+
+ /**
+ * @todo We can violate this ASSERT() when fairness/sleep sets
+ * conflict to cause an execution to terminate, e.g. with:
+ * Scheduler: [0: disabled][1: disabled][2: sleep][3: current, enabled]
+ */
+ //ASSERT(scheduler->all_threads_sleeping());
+ }
}
/** @brief Print execution stats */
}
/**
- * Processes a read or rmw model action.
+ * Processes a read model action.
* @param curr is the read model action to process.
- * @param second_part_of_rmw is boolean that is true is this is the second action of a rmw.
* @return True if processing this read updates the mo_graph.
*/
-bool ModelChecker::process_read(ModelAction *curr, bool second_part_of_rmw)
+bool ModelChecker::process_read(ModelAction *curr)
{
- uint64_t value = VALUE_NONE;
- bool updated = false;
+ Node *node = curr->get_node();
while (true) {
- const ModelAction *reads_from = curr->get_node()->get_read_from();
- if (reads_from != NULL) {
- mo_graph->startChanges();
+ bool updated = false;
+ switch (node->get_read_from_status()) {
+ case READ_FROM_PAST: {
+ const ModelAction *rf = node->get_read_from_past();
+ ASSERT(rf);
- value = reads_from->get_value();
- bool r_status = false;
-
- if (!second_part_of_rmw) {
- check_recency(curr, reads_from);
- r_status = r_modification_order(curr, reads_from);
- }
+ mo_graph->startChanges();
- if (!second_part_of_rmw && is_infeasible() && (curr->get_node()->increment_read_from() || curr->get_node()->increment_future_value())) {
- mo_graph->rollbackChanges();
- priv->too_many_reads = false;
- continue;
+ ASSERT(!is_infeasible());
+ if (!check_recency(curr, rf)) {
+ if (node->increment_read_from()) {
+ mo_graph->rollbackChanges();
+ continue;
+ } else {
+ priv->too_many_reads = true;
+ }
}
- read_from(curr, reads_from);
+ updated = r_modification_order(curr, rf);
+ read_from(curr, rf);
mo_graph->commitChanges();
mo_check_promises(curr, true);
-
- updated |= r_status;
- } else if (!second_part_of_rmw) {
+ break;
+ }
+ case READ_FROM_PROMISE: {
+ Promise *promise = curr->get_node()->get_read_from_promise();
+ if (promise->add_reader(curr))
+ priv->failed_promise = true;
+ curr->set_read_from_promise(promise);
+ mo_graph->startChanges();
+ if (!check_recency(curr, promise))
+ priv->too_many_reads = true;
+ updated = r_modification_order(curr, promise);
+ mo_graph->commitChanges();
+ break;
+ }
+ case READ_FROM_FUTURE: {
/* Read from future value */
- struct future_value fv = curr->get_node()->get_future_value();
+ struct future_value fv = node->get_future_value();
Promise *promise = new Promise(curr, fv);
- value = fv.value;
curr->set_read_from_promise(promise);
promises->push_back(promise);
mo_graph->startChanges();
updated = r_modification_order(curr, promise);
mo_graph->commitChanges();
+ break;
+ }
+ default:
+ ASSERT(false);
}
- get_thread(curr)->set_return_value(value);
+ get_thread(curr)->set_return_value(curr->get_return_value());
return updated;
}
}
*/
bool ModelChecker::process_mutex(ModelAction *curr)
{
- std::mutex *mutex = NULL;
+ std::mutex *mutex = curr->get_mutex();
struct std::mutex_state *state = NULL;
- if (curr->is_trylock() || curr->is_lock() || curr->is_unlock()) {
- mutex = (std::mutex *)curr->get_location();
- state = mutex->get_state();
- } else if (curr->is_wait()) {
- mutex = (std::mutex *)curr->get_value();
+ if (mutex)
state = mutex->get_state();
- }
switch (curr->get_type()) {
case ATOMIC_TRYLOCK: {
- bool success = !state->islocked;
+ bool success = !state->locked;
curr->set_try_lock(success);
if (!success) {
get_thread(curr)->set_return_value(0);
case ATOMIC_LOCK: {
if (curr->get_cv()->getClock(state->alloc_tid) <= state->alloc_clock)
assert_bug("Lock access before initialization");
- state->islocked = true;
+ state->locked = get_thread(curr);
ModelAction *unlock = get_last_unlock(curr);
//synchronize with the previous unlock statement
if (unlock != NULL) {
}
case ATOMIC_UNLOCK: {
//unlock the lock
- state->islocked = false;
+ state->locked = NULL;
//wake up the other threads
action_list_t *waiters = get_safe_ptr_action(lock_waiters_map, curr->get_location());
//activate all the waiting threads
}
case ATOMIC_WAIT: {
//unlock the lock
- state->islocked = false;
+ state->locked = NULL;
//wake up the other threads
action_list_t *waiters = get_safe_ptr_action(lock_waiters_map, (void *) curr->get_value());
//activate all the waiting threads
write_thread = write_thread->get_parent();
struct future_value fv = {
- writer->get_value(),
+ writer->get_write_value(),
writer->get_seq_number() + params.maxfuturedelay,
write_thread->get_id(),
};
*/
bool ModelChecker::process_write(ModelAction *curr)
{
- bool updated_mod_order = w_modification_order(curr);
- bool updated_promises = resolve_promises(curr);
+ /* Readers to which we may send our future value */
+ std::vector< ModelAction *, ModelAlloc<ModelAction *> > send_fv;
+
+ bool updated_mod_order = w_modification_order(curr, &send_fv);
+ int promise_idx = get_promise_to_resolve(curr);
+ const ModelAction *earliest_promise_reader;
+ bool updated_promises = false;
+
+ if (promise_idx >= 0) {
+ earliest_promise_reader = (*promises)[promise_idx]->get_reader(0);
+ updated_promises = resolve_promise(curr, promise_idx);
+ } else
+ earliest_promise_reader = NULL;
+
+ /* Don't send future values to reads after the Promise we resolve */
+ for (unsigned int i = 0; i < send_fv.size(); i++) {
+ ModelAction *read = send_fv[i];
+ if (!earliest_promise_reader || *read < *earliest_promise_reader)
+ futurevalues->push_back(PendingFutureValue(curr, read));
+ }
if (promises->size() == 0) {
for (unsigned int i = 0; i < futurevalues->size(); i++) {
case THREAD_CREATE: {
thrd_t *thrd = (thrd_t *)curr->get_location();
struct thread_params *params = (struct thread_params *)curr->get_value();
- Thread *th = new Thread(thrd, params->func, params->arg);
+ Thread *th = new Thread(thrd, params->func, params->arg, get_thread(curr));
add_thread(th);
th->set_creation(curr);
/* Promises can be satisfied by children */
*/
bool ModelChecker::read_from(ModelAction *act, const ModelAction *rf)
{
+ ASSERT(rf);
act->set_read_from(rf);
- if (rf != NULL && act->is_acquire()) {
+ if (act->is_acquire()) {
rel_heads_list_t release_heads;
get_release_seq_heads(act, act, &release_heads);
int num_heads = release_heads.size();
return false;
}
+/**
+ * Check promises and eliminate potentially-satisfying threads when a thread is
+ * blocked (e.g., join, lock). A thread which is waiting on another thread can
+ * no longer satisfy a promise generated from that thread.
+ *
+ * @param blocker The thread on which a thread is waiting
+ * @param waiting The waiting thread
+ */
+void ModelChecker::thread_blocking_check_promises(Thread *blocker, Thread *waiting)
+{
+ for (unsigned int i = 0; i < promises->size(); i++) {
+ Promise *promise = (*promises)[i];
+ if (!promise->thread_is_available(waiting->get_id()))
+ continue;
+ for (unsigned int j = 0; j < promise->get_num_readers(); j++) {
+ ModelAction *reader = promise->get_reader(j);
+ if (reader->get_tid() != blocker->get_id())
+ continue;
+ if (promise->eliminate_thread(waiting->get_id())) {
+ /* Promise has failed */
+ priv->failed_promise = true;
+ } else {
+ /* Only eliminate the 'waiting' thread once */
+ return;
+ }
+ }
+ }
+}
+
/**
* @brief Check whether a model action is enabled.
*
if (curr->is_lock()) {
std::mutex *lock = (std::mutex *)curr->get_location();
struct std::mutex_state *state = lock->get_state();
- if (state->islocked) {
+ if (state->locked) {
//Stick the action in the appropriate waiting queue
get_safe_ptr_action(lock_waiters_map, curr->get_location())->push_back(curr);
return false;
Thread *blocking = (Thread *)curr->get_location();
if (!blocking->is_complete()) {
blocking->push_wait_list(curr);
+ thread_blocking_check_promises(blocking, get_thread(curr));
return false;
}
}
/* Build may_read_from set for newly-created actions */
if (newly_explored && curr->is_read())
- build_reads_from_past(curr);
+ build_may_read_from(curr);
/* Initialize work_queue with the "current action" work */
work_queue_t work_queue(1, CheckCurrWorkEntry(curr));
if (process_thread_action(curr))
update_all = true;
- if (act->is_read() && process_read(act, second_part_of_rmw))
+ if (act->is_read() && !second_part_of_rmw && process_read(act))
update = true;
if (act->is_write() && process_write(act))
}
}
if (act->is_write()) {
- if (w_modification_order(act))
+ if (w_modification_order(act, NULL))
updated = true;
}
mo_graph->commitChanges();
if ((parnode && !parnode->backtrack_empty()) ||
!currnode->misc_empty() ||
!currnode->read_from_empty() ||
- !currnode->future_value_empty() ||
!currnode->promise_empty() ||
!currnode->relseq_break_empty()) {
set_latest_backtrack(curr);
}
/**
- * Checks whether a thread has read from the same write for too many times
- * without seeing the effects of a later write.
- *
- * Basic idea:
- * 1) there must a different write that we could read from that would satisfy the modification order,
- * 2) we must have read from the same value in excess of maxreads times, and
- * 3) that other write must have been in the reads_from set for maxreads times.
+ * A helper function for ModelChecker::check_recency, to check if the current
+ * thread is able to read from a different write/promise for 'params.maxreads'
+ * number of steps and if that write/promise should become visible (i.e., is
+ * ordered later in the modification order). This helps model memory liveness.
*
- * If so, we decide that the execution is no longer feasible.
+ * @param curr The current action. Must be a read.
+ * @param rf The write/promise from which we plan to read
+ * @param other_rf The write/promise from which we may read
+ * @return True if we were able to read from other_rf for params.maxreads steps
*/
-void ModelChecker::check_recency(ModelAction *curr, const ModelAction *rf)
+template <typename T, typename U>
+bool ModelChecker::should_read_instead(const ModelAction *curr, const T *rf, const U *other_rf) const
{
- if (params.maxreads != 0) {
- if (curr->get_node()->get_read_from_size() <= 1)
- return;
- //Must make sure that execution is currently feasible... We could
- //accidentally clear by rolling back
- if (is_infeasible())
- return;
- std::vector<action_list_t> *thrd_lists = get_safe_ptr_vect_action(obj_thrd_map, curr->get_location());
- int tid = id_to_int(curr->get_tid());
-
- /* Skip checks */
- if ((int)thrd_lists->size() <= tid)
- return;
- action_list_t *list = &(*thrd_lists)[tid];
-
- action_list_t::reverse_iterator rit = list->rbegin();
- /* Skip past curr */
- for (; (*rit) != curr; rit++)
- ;
- /* go past curr now */
- rit++;
-
- action_list_t::reverse_iterator ritcopy = rit;
- //See if we have enough reads from the same value
- int count = 0;
- for (; count < params.maxreads; rit++, count++) {
- if (rit == list->rend())
- return;
- ModelAction *act = *rit;
- if (!act->is_read())
- return;
-
- if (act->get_reads_from() != rf)
- return;
- if (act->get_node()->get_read_from_size() <= 1)
- return;
- }
- for (int i = 0; i < curr->get_node()->get_read_from_size(); i++) {
- /* Get write */
- const ModelAction *write = curr->get_node()->get_read_from_at(i);
+ /* Need a different write/promise */
+ if (other_rf->equals(rf))
+ return false;
- /* Need a different write */
- if (write == rf)
- continue;
+ /* Only look for "newer" writes/promises */
+ if (!mo_graph->checkReachable(rf, other_rf))
+ return false;
- /* Test to see whether this is a feasible write to read from */
- /** NOTE: all members of read-from set should be
- * feasible, so we no longer check it here **/
+ std::vector<action_list_t> *thrd_lists = get_safe_ptr_vect_action(obj_thrd_map, curr->get_location());
+ action_list_t *list = &(*thrd_lists)[id_to_int(curr->get_tid())];
+ action_list_t::reverse_iterator rit = list->rbegin();
+ ASSERT((*rit) == curr);
+ /* Skip past curr */
+ rit++;
+
+ /* Does this write/promise work for everyone? */
+ for (int i = 0; i < params.maxreads; i++, rit++) {
+ ModelAction *act = *rit;
+ if (!act->may_read_from(other_rf))
+ return false;
+ }
+ return true;
+}
- rit = ritcopy;
+/**
+ * Checks whether a thread has read from the same write or Promise for too many
+ * times without seeing the effects of a later write/Promise.
+ *
+ * Basic idea:
+ * 1) there must a different write/promise that we could read from,
+ * 2) we must have read from the same write/promise in excess of maxreads times,
+ * 3) that other write/promise must have been in the reads_from set for maxreads times, and
+ * 4) that other write/promise must be mod-ordered after the write/promise we are reading.
+ *
+ * If so, we decide that the execution is no longer feasible.
+ *
+ * @param curr The current action. Must be a read.
+ * @param rf The ModelAction/Promise from which we might read.
+ * @return True if the read should succeed; false otherwise
+ */
+template <typename T>
+bool ModelChecker::check_recency(ModelAction *curr, const T *rf) const
+{
+ if (!params.maxreads)
+ return true;
- bool feasiblewrite = true;
- //new we need to see if this write works for everyone
+ //NOTE: Next check is just optimization, not really necessary....
+ if (curr->get_node()->get_read_from_past_size() +
+ curr->get_node()->get_read_from_promise_size() <= 1)
+ return true;
- for (int loop = count; loop > 0; loop--, rit++) {
- ModelAction *act = *rit;
- bool foundvalue = false;
- for (int j = 0; j < act->get_node()->get_read_from_size(); j++) {
- if (act->get_node()->get_read_from_at(j) == write) {
- foundvalue = true;
- break;
- }
- }
- if (!foundvalue) {
- feasiblewrite = false;
- break;
- }
- }
- if (feasiblewrite) {
- priv->too_many_reads = true;
- return;
- }
- }
+ std::vector<action_list_t> *thrd_lists = get_safe_ptr_vect_action(obj_thrd_map, curr->get_location());
+ int tid = id_to_int(curr->get_tid());
+ ASSERT(tid < (int)thrd_lists->size());
+ action_list_t *list = &(*thrd_lists)[tid];
+ action_list_t::reverse_iterator rit = list->rbegin();
+ ASSERT((*rit) == curr);
+ /* Skip past curr */
+ rit++;
+
+ action_list_t::reverse_iterator ritcopy = rit;
+ /* See if we have enough reads from the same value */
+ for (int count = 0; count < params.maxreads; ritcopy++, count++) {
+ if (ritcopy == list->rend())
+ return true;
+ ModelAction *act = *ritcopy;
+ if (!act->is_read())
+ return true;
+ if (act->get_reads_from_promise() && !act->get_reads_from_promise()->equals(rf))
+ return true;
+ if (act->get_reads_from() && !act->get_reads_from()->equals(rf))
+ return true;
+ if (act->get_node()->get_read_from_past_size() +
+ act->get_node()->get_read_from_promise_size() <= 1)
+ return true;
+ }
+ for (int i = 0; i < curr->get_node()->get_read_from_past_size(); i++) {
+ const ModelAction *write = curr->get_node()->get_read_from_past(i);
+ if (should_read_instead(curr, rf, write))
+ return false; /* liveness failure */
+ }
+ for (int i = 0; i < curr->get_node()->get_read_from_promise_size(); i++) {
+ const Promise *promise = curr->get_node()->get_read_from_promise(i);
+ if (should_read_instead(curr, rf, promise))
+ return false; /* liveness failure */
}
+ return true;
}
/**
added = mo_graph->addEdge(act, rf) || added;
}
} else {
- const ModelAction *prevreadfrom = act->get_reads_from();
- //if the previous read is unresolved, keep going...
- if (prevreadfrom == NULL)
- continue;
-
- if (!prevreadfrom->equals(rf)) {
- added = mo_graph->addEdge(prevreadfrom, rf) || added;
+ const ModelAction *prevrf = act->get_reads_from();
+ const Promise *prevrf_promise = act->get_reads_from_promise();
+ if (prevrf) {
+ if (!prevrf->equals(rf))
+ added = mo_graph->addEdge(prevrf, rf) || added;
+ } else if (!prevrf_promise->equals(rf)) {
+ added = mo_graph->addEdge(prevrf_promise, rf) || added;
}
}
break;
* (II) Sending the write back to non-synchronizing reads.
*
* @param curr The current action. Must be a write.
+ * @param send_fv A vector for stashing reads to which we may pass our future
+ * value. If NULL, then don't record any future values.
* @return True if modification order edges were added; false otherwise
*/
-bool ModelChecker::w_modification_order(ModelAction *curr)
+bool ModelChecker::w_modification_order(ModelAction *curr, std::vector< ModelAction *, ModelAlloc<ModelAction *> > *send_fv)
{
std::vector<action_list_t> *thrd_lists = get_safe_ptr_vect_action(obj_thrd_map, curr->get_location());
unsigned int i;
pendingfuturevalue.
*/
- if (thin_air_constraint_may_allow(curr, act)) {
+ if (send_fv && thin_air_constraint_may_allow(curr, act)) {
if (!is_infeasible())
- futurevalues->push_back(PendingFutureValue(curr, act));
+ send_fv->push_back(act);
else if (curr->is_rmw() && act->is_rmw() && curr->get_reads_from() && curr->get_reads_from() == act->get_reads_from())
add_future_value(curr, act);
}
}
/**
- * Resolve a set of Promises with a current write. The set is provided in the
- * Node corresponding to @a write.
+ * @brief Find the promise, if any to resolve for the current action
+ * @param curr The current ModelAction. Should be a write.
+ * @return The (non-negative) index for the Promise to resolve, if any;
+ * otherwise -1
+ */
+int ModelChecker::get_promise_to_resolve(const ModelAction *curr) const
+{
+ for (unsigned int i = 0; i < promises->size(); i++)
+ if (curr->get_node()->get_promise(i))
+ return i;
+ return -1;
+}
+
+/**
+ * Resolve a Promise with a current write.
* @param write The ModelAction that is fulfilling Promises
- * @return True if promises were resolved; false otherwise
+ * @param promise_idx The index corresponding to the promise
+ * @return True if the Promise was successfully resolved; false otherwise
*/
-bool ModelChecker::resolve_promises(ModelAction *write)
+bool ModelChecker::resolve_promise(ModelAction *write, unsigned int promise_idx)
{
- bool haveResolved = false;
std::vector< ModelAction *, ModelAlloc<ModelAction *> > actions_to_check;
- promise_list_t mustResolve, resolved;
-
- for (unsigned int i = 0, promise_index = 0; promise_index < promises->size(); i++) {
- Promise *promise = (*promises)[promise_index];
- if (write->get_node()->get_promise(i)) {
- ModelAction *read = promise->get_action();
- read_from(read, write);
- //Make sure the promise's value matches the write's value
- ASSERT(promise->is_compatible(write));
- mo_graph->resolvePromise(read, write, &mustResolve);
+ Promise *promise = (*promises)[promise_idx];
- resolved.push_back(promise);
- promises->erase(promises->begin() + promise_index);
- actions_to_check.push_back(read);
-
- haveResolved = true;
- } else
- promise_index++;
+ for (unsigned int i = 0; i < promise->get_num_readers(); i++) {
+ ModelAction *read = promise->get_reader(i);
+ read_from(read, write);
+ actions_to_check.push_back(read);
}
+ /* Make sure the promise's value matches the write's value */
+ ASSERT(promise->is_compatible(write) && promise->same_value(write));
+ if (!mo_graph->resolvePromise(promise, write))
+ priv->failed_promise = true;
+
+ promises->erase(promises->begin() + promise_idx);
+ /**
+ * @todo It is possible to end up in an inconsistent state, where a
+ * "resolved" promise may still be referenced if
+ * CycleGraph::resolvePromise() failed, so don't delete 'promise'.
+ *
+ * Note that the inconsistency only matters when dumping mo_graph to
+ * file.
+ *
+ * delete promise;
+ */
- for (unsigned int i = 0; i < mustResolve.size(); i++) {
- if (std::find(resolved.begin(), resolved.end(), mustResolve[i])
- == resolved.end())
- priv->failed_promise = true;
- }
- for (unsigned int i = 0; i < resolved.size(); i++)
- delete resolved[i];
//Check whether reading these writes has made threads unable to
//resolve promises
-
for (unsigned int i = 0; i < actions_to_check.size(); i++) {
ModelAction *read = actions_to_check[i];
mo_check_promises(read, true);
}
- return haveResolved;
+ return true;
}
/**
{
for (unsigned int i = 0; i < promises->size(); i++) {
Promise *promise = (*promises)[i];
- const ModelAction *act = promise->get_action();
- if (!act->happens_before(curr) &&
- act->is_read() &&
- !act->could_synchronize_with(curr) &&
- !act->same_thread(curr) &&
- act->get_location() == curr->get_location() &&
- promise->get_value() == curr->get_value()) {
- curr->get_node()->set_promise(i, act->is_rmw());
+ if (!promise->is_compatible(curr) || !promise->same_value(curr))
+ continue;
+
+ bool satisfy = true;
+ for (unsigned int j = 0; j < promise->get_num_readers(); j++) {
+ const ModelAction *act = promise->get_reader(j);
+ if (act->happens_before(curr) ||
+ act->could_synchronize_with(curr)) {
+ satisfy = false;
+ break;
+ }
}
+ if (satisfy)
+ curr->get_node()->set_promise(i);
}
}
{
for (unsigned int i = 0; i < promises->size(); i++) {
Promise *promise = (*promises)[i];
- const ModelAction *act = promise->get_action();
- if ((old_cv == NULL || !old_cv->synchronized_since(act)) &&
- merge_cv->synchronized_since(act)) {
- if (promise->eliminate_thread(tid)) {
- //Promise has failed
- priv->failed_promise = true;
- return;
+ if (!promise->thread_is_available(tid))
+ continue;
+ for (unsigned int j = 0; j < promise->get_num_readers(); j++) {
+ const ModelAction *act = promise->get_reader(j);
+ if ((!old_cv || !old_cv->synchronized_since(act)) &&
+ merge_cv->synchronized_since(act)) {
+ if (promise->eliminate_thread(tid)) {
+ /* Promise has failed */
+ priv->failed_promise = true;
+ return;
+ }
}
}
}
for (unsigned int i = 0; i < promises->size(); i++) {
Promise *promise = (*promises)[i];
- const ModelAction *pread = promise->get_action();
// Is this promise on the same location?
- if (!pread->same_var(write))
+ if (!promise->same_location(write))
continue;
- if (pread->happens_before(act) && mo_graph->checkPromise(write, promise)) {
- priv->failed_promise = true;
- return;
+ for (unsigned int j = 0; j < promise->get_num_readers(); j++) {
+ const ModelAction *pread = promise->get_reader(j);
+ if (!pread->happens_before(act))
+ continue;
+ if (mo_graph->checkPromise(write, promise)) {
+ priv->failed_promise = true;
+ return;
+ }
+ break;
}
// Don't do any lookups twice for the same thread
/**
* Build up an initial set of all past writes that this 'read' action may read
- * from. This set is determined by the clock vector's "happens before"
- * relationship.
+ * from, as well as any previously-observed future values that must still be valid.
+ *
* @param curr is the current ModelAction that we are exploring; it must be a
* 'read' operation.
*/
-void ModelChecker::build_reads_from_past(ModelAction *curr)
+void ModelChecker::build_may_read_from(ModelAction *curr)
{
std::vector<action_list_t> *thrd_lists = get_safe_ptr_vect_action(obj_thrd_map, curr->get_location());
unsigned int i;
mo_graph->startChanges();
r_modification_order(curr, act);
if (!is_infeasible())
- curr->get_node()->add_read_from(act);
+ curr->get_node()->add_read_from_past(act);
mo_graph->rollbackChanges();
}
break;
}
}
+
+ /* Inherit existing, promised future values */
+ for (i = 0; i < promises->size(); i++) {
+ const Promise *promise = (*promises)[i];
+ const ModelAction *promise_read = promise->get_reader(0);
+ if (promise_read->same_var(curr)) {
+ /* Only add feasible future-values */
+ mo_graph->startChanges();
+ r_modification_order(curr, promise);
+ if (!is_infeasible())
+ curr->get_node()->add_read_from_promise(promise_read);
+ mo_graph->rollbackChanges();
+ }
+ }
+
/* We may find no valid may-read-from only if the execution is doomed */
- if (!curr->get_node()->get_read_from_size()) {
+ if (!curr->get_node()->read_from_size()) {
priv->no_valid_reads = true;
set_assert();
}
if (DBG_ENABLED()) {
model_print("Reached read action:\n");
curr->print();
- model_print("Printing may_read_from\n");
- curr->get_node()->print_may_read_from();
- model_print("End printing may_read_from\n");
+ model_print("Printing read_from_past\n");
+ curr->get_node()->print_read_from_past();
+ model_print("End printing read_from_past\n");
}
}
ModelAction **thread_array = (ModelAction **)model_calloc(1, sizeof(ModelAction *) * get_num_threads());
for (action_list_t::iterator it = action_trace->begin(); it != action_trace->end(); it++) {
- ModelAction *action = *it;
- if (action->is_read()) {
- fprintf(file, "N%u [label=\"N%u, T%u\"];\n", action->get_seq_number(), action->get_seq_number(), action->get_tid());
- if (action->get_reads_from() != NULL)
- fprintf(file, "N%u -> N%u[label=\"rf\", color=red];\n", action->get_seq_number(), action->get_reads_from()->get_seq_number());
+ ModelAction *act = *it;
+ if (act->is_read()) {
+ mo_graph->dot_print_node(file, act);
+ if (act->get_reads_from())
+ mo_graph->dot_print_edge(file,
+ act->get_reads_from(),
+ act,
+ "label=\"rf\", color=red, weight=2");
+ else
+ mo_graph->dot_print_edge(file,
+ act->get_reads_from_promise(),
+ act,
+ "label=\"rf\", color=red");
}
- if (thread_array[action->get_tid()] != NULL) {
- fprintf(file, "N%u -> N%u[label=\"sb\", color=blue];\n", thread_array[action->get_tid()]->get_seq_number(), action->get_seq_number());
+ if (thread_array[act->get_tid()]) {
+ mo_graph->dot_print_edge(file,
+ thread_array[id_to_int(act->get_tid())],
+ act,
+ "label=\"sb\", color=blue, weight=400");
}
- thread_array[action->get_tid()] = action;
+ thread_array[act->get_tid()] = act;
}
fprintf(file, "}\n");
model_free(thread_array);
#endif
model_print("Execution %d:", stats.num_total);
- if (isfeasibleprefix())
+ if (isfeasibleprefix()) {
+ if (scheduler->all_threads_sleeping())
+ model_print(" SLEEP-SET REDUNDANT");
model_print("\n");
- else
+ } else
print_infeasibility(" INFEASIBLE");
print_list(action_trace);
model_print("\n");
return get_thread(act->get_tid());
}
+/**
+ * @brief Get a Promise's "promise number"
+ *
+ * A "promise number" is an index number that is unique to a promise, valid
+ * only for a specific snapshot of an execution trace. Promises may come and go
+ * as they are generated an resolved, so an index only retains meaning for the
+ * current snapshot.
+ *
+ * @param promise The Promise to check
+ * @return The promise index, if the promise still is valid; otherwise -1
+ */
+int ModelChecker::get_promise_number(const Promise *promise) const
+{
+ for (unsigned int i = 0; i < promises->size(); i++)
+ if ((*promises)[i] == promise)
+ return i;
+ /* Not found */
+ return -1;
+}
+
/**
* @brief Check if a Thread is currently enabled
* @param t The Thread to check
{
do {
thrd_t user_thread;
- Thread *t = new Thread(&user_thread, &user_main_wrapper, NULL);
+ Thread *t = new Thread(&user_thread, &user_main_wrapper, NULL, NULL);
add_thread(t);
do {
Thread *thr = get_thread(tid);
if (!thr->is_model_thread() && !thr->is_complete() && !thr->get_pending()) {
switch_from_master(thr);
+ if (is_circular_wait(thr))
+ assert_bug("Deadlock detected");
}
}
projects / model-checker.git / blobdiff