X-Git-Url: http://plrg.eecs.uci.edu/git/?p=model-checker.git;a=blobdiff_plain;f=model.cc;h=1e730d794baca5dc99387053bb98125b3756193a;hp=c3f6372517d591c5016cb91127adf36ae8fadb36;hb=023c2e9d75b5f4460d1e079e4915b1c41a8045a4;hpb=80ab61e4168b993a319788c70fd41e63a34ba627 diff --git a/model.cc b/model.cc index c3f6372..1e730d7 100644 --- a/model.cc +++ b/model.cc @@ -1,5 +1,6 @@ #include #include +#include #include "model.h" #include "action.h" @@ -11,8 +12,7 @@ #include "cyclegraph.h" #include "promise.h" #include "datarace.h" -#include "mutex.h" -#include "threads.h" +#include "threads-model.h" #define INITIAL_THREAD_ID 0 @@ -31,11 +31,12 @@ ModelChecker::ModelChecker(struct model_params params) : thread_map(new HashTable()), obj_map(new HashTable()), lock_waiters_map(new HashTable()), + condvar_waiters_map(new HashTable()), obj_thrd_map(new HashTable, uintptr_t, 4 >()), - promises(new std::vector()), - futurevalues(new std::vector()), - pending_rel_seqs(new std::vector()), - thrd_last_action(new std::vector(1)), + promises(new std::vector< Promise *, SnapshotAlloc >()), + futurevalues(new std::vector< struct PendingFutureValue, SnapshotAlloc >()), + pending_rel_seqs(new std::vector< struct release_seq *, SnapshotAlloc >()), + thrd_last_action(new std::vector< ModelAction *, SnapshotAlloc >(1)), node_stack(new NodeStack()), mo_graph(new CycleGraph()), failed_promise(false), @@ -47,6 +48,10 @@ ModelChecker::ModelChecker(struct model_params params) : priv = (struct model_snapshot_members *)calloc(1, sizeof(*priv)); /* First thread created will have id INITIAL_THREAD_ID */ priv->next_thread_id = INITIAL_THREAD_ID; + + /* Initialize a model-checker thread, for special ModelActions */ + model_thread = new Thread(get_next_id()); + thread_map->put(id_to_int(model_thread->get_id()), model_thread); } /** @brief Destructor */ @@ -59,6 +64,7 @@ ModelChecker::~ModelChecker() delete obj_thrd_map; delete obj_map; delete lock_waiters_map; + delete condvar_waiters_map; delete action_trace; for (unsigned int i = 0; i < promises->size(); i++) @@ -112,6 +118,10 @@ modelclock_t ModelChecker::get_next_seq_num() return ++priv->used_sequence_numbers; } +Node * ModelChecker::get_curr_node() { + return node_stack->get_head(); +} + /** * @brief Choose the next thread to execute. * @@ -150,8 +160,15 @@ Thread * ModelChecker::get_next_thread(ModelAction *curr) earliest_diverge=diverge; Node *nextnode = next->get_node(); + Node *prevnode = nextnode->get_parent(); + scheduler->update_sleep_set(prevnode); + /* Reached divergence point */ - if (nextnode->increment_promise()) { + if (nextnode->increment_misc()) { + /* The next node will try to satisfy a different misc_index values. */ + tid = next->get_tid(); + node_stack->pop_restofstack(2); + } else if (nextnode->increment_promise()) { /* The next node will try to satisfy a different set of promises. */ tid = next->get_tid(); node_stack->pop_restofstack(2); @@ -163,15 +180,23 @@ Thread * ModelChecker::get_next_thread(ModelAction *curr) /* 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(); + node_stack->pop_restofstack(2); } else { /* Make a different thread execute for next step */ - Node *node = nextnode->get_parent(); - tid = node->get_next_backtrack(); + scheduler->add_sleep(thread_map->get(id_to_int(next->get_tid()))); + tid = prevnode->get_next_backtrack(); + /* Make sure the backtracked thread isn't sleeping. */ node_stack->pop_restofstack(1); if (diverge==earliest_diverge) { - earliest_diverge=node->get_action(); + earliest_diverge=prevnode->get_action(); } } + /* The correct sleep set is in the parent node. */ + execute_sleep_set(); + DEBUG("*** Divergence point ***\n"); diverge = NULL; @@ -183,6 +208,42 @@ Thread * ModelChecker::get_next_thread(ModelAction *curr) return thread_map->get(id_to_int(tid)); } +/** + * We need to know what the next actions of all threads in the sleep + * set will be. This method computes them and stores the actions at + * the corresponding thread object's pending action. + */ + +void ModelChecker::execute_sleep_set() { + for(unsigned int i=0;iget_enabled(thr) == THREAD_SLEEP_SET && + thr->get_pending() == NULL ) { + thr->set_state(THREAD_RUNNING); + scheduler->next_thread(thr); + Thread::swap(&system_context, thr); + priv->current_action->set_sleep_flag(); + thr->set_pending(priv->current_action); + } + } + priv->current_action = NULL; +} + +void ModelChecker::wake_up_sleeping_actions(ModelAction * curr) { + for(unsigned int i=0;iget_enabled(thr) == THREAD_SLEEP_SET ) { + ModelAction *pending_act=thr->get_pending(); + if ((!curr->is_rmwr())&&pending_act->could_synchronize_with(curr)) { + //Remove this thread from sleep set + scheduler->remove_sleep(thr); + } + } + } +} + /** * Queries the model-checker for more executions to explore and, if one * exists, resets the model-checker state to execute a new execution. @@ -207,11 +268,14 @@ bool ModelChecker::next_execution() num_feasible_executions++; } - DEBUG("Number of acquires waiting on pending release sequences: %lu\n", + DEBUG("Number of acquires waiting on pending release sequences: %zu\n", pending_rel_seqs->size()); - if (isfinalfeasible() || DBG_ENABLED()) + + if (isfinalfeasible() || (params.bound != 0 && priv->used_sequence_numbers > params.bound ) || DBG_ENABLED() ) { + checkDataRaces(); print_summary(); + } if ((diverge = get_next_backtrack()) == NULL) return false; @@ -264,13 +328,39 @@ ModelAction * ModelChecker::get_last_conflict(ModelAction *act) } break; } + case ATOMIC_WAIT: { + /* linear search: from most recent to oldest */ + action_list_t *list = obj_map->get_safe_ptr(act->get_location()); + action_list_t::reverse_iterator rit; + for (rit = list->rbegin(); rit != list->rend(); rit++) { + ModelAction *prev = *rit; + if (!act->same_thread(prev)&&prev->is_failed_trylock()) + return prev; + if (!act->same_thread(prev)&&prev->is_notify()) + return prev; + } + break; + } + + case ATOMIC_NOTIFY_ALL: + case ATOMIC_NOTIFY_ONE: { + /* linear search: from most recent to oldest */ + action_list_t *list = obj_map->get_safe_ptr(act->get_location()); + action_list_t::reverse_iterator rit; + for (rit = list->rbegin(); rit != list->rend(); rit++) { + ModelAction *prev = *rit; + if (!act->same_thread(prev)&&prev->is_wait()) + return prev; + } + break; + } default: break; } return NULL; } -/** This method find backtracking points where we should try to +/** This method finds backtracking points where we should try to * reorder the parameter ModelAction against. * * @param the ModelAction to find backtracking points for. @@ -295,9 +385,15 @@ void ModelChecker::set_backtracking(ModelAction *act) for(int i = low_tid; i < high_tid; i++) { thread_id_t tid = int_to_id(i); - if (!node->is_enabled(tid)) - continue; + /* Make sure this thread can be enabled here. */ + if (i >= node->get_num_threads()) + break; + + /* Don't backtrack into a point where the thread is disabled or sleeping. */ + if (node->enabled_status(tid)!=THREAD_ENABLED) + continue; + /* Check if this has been explored already */ if (node->has_been_explored(tid)) continue; @@ -315,7 +411,6 @@ void ModelChecker::set_backtracking(ModelAction *act) if (unfair) continue; } - /* Cache the latest backtracking point */ if (!priv->next_backtrack || *prev > *priv->next_backtrack) priv->next_backtrack = prev; @@ -353,7 +448,7 @@ ModelAction * ModelChecker::get_next_backtrack() */ bool ModelChecker::process_read(ModelAction *curr, bool second_part_of_rmw) { - uint64_t value; + uint64_t value = VALUE_NONE; bool updated = false; while (true) { const ModelAction *reads_from = curr->get_node()->get_read_from(); @@ -410,8 +505,17 @@ bool ModelChecker::process_read(ModelAction *curr, bool second_part_of_rmw) * @return True if synchronization was updated; false otherwise */ bool ModelChecker::process_mutex(ModelAction *curr) { - std::mutex *mutex = (std::mutex *)curr->get_location(); - struct std::mutex_state *state = mutex->get_state(); + std::mutex *mutex=NULL; + 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(); + state = mutex->get_state(); + } + switch (curr->get_type()) { case ATOMIC_TRYLOCK: { bool success = !state->islocked; @@ -449,6 +553,43 @@ bool ModelChecker::process_mutex(ModelAction *curr) { waiters->clear(); break; } + case ATOMIC_WAIT: { + //unlock the lock + state->islocked = false; + //wake up the other threads + action_list_t *waiters = lock_waiters_map->get_safe_ptr((void *) curr->get_value()); + //activate all the waiting threads + for (action_list_t::iterator rit = waiters->begin(); rit != waiters->end(); rit++) { + scheduler->wake(get_thread(*rit)); + } + waiters->clear(); + //check whether we should go to sleep or not...simulate spurious failures + if (curr->get_node()->get_misc()==0) { + condvar_waiters_map->get_safe_ptr(curr->get_location())->push_back(curr); + //disable us + scheduler->sleep(get_current_thread()); + } + break; + } + case ATOMIC_NOTIFY_ALL: { + action_list_t *waiters = condvar_waiters_map->get_safe_ptr(curr->get_location()); + //activate all the waiting threads + for (action_list_t::iterator rit = waiters->begin(); rit != waiters->end(); rit++) { + scheduler->wake(get_thread(*rit)); + } + waiters->clear(); + break; + } + case ATOMIC_NOTIFY_ONE: { + action_list_t *waiters = condvar_waiters_map->get_safe_ptr(curr->get_location()); + int wakeupthread=curr->get_node()->get_misc(); + action_list_t::iterator it = waiters->begin(); + advance(it, wakeupthread); + scheduler->wake(get_thread(*it)); + waiters->erase(it); + break; + } + default: ASSERT(0); } @@ -468,7 +609,9 @@ bool ModelChecker::process_write(ModelAction *curr) if (promises->size() == 0) { for (unsigned int i = 0; i < futurevalues->size(); i++) { struct PendingFutureValue pfv = (*futurevalues)[i]; - if (pfv.act->get_node()->add_future_value(pfv.value, pfv.expiration) && + //Do more ambitious checks now that mo is more complete + if (mo_may_allow(pfv.writer, pfv.act)&& + pfv.act->get_node()->add_future_value(pfv.writer->get_value(), pfv.writer->get_seq_number()+params.maxfuturedelay) && (!priv->next_backtrack || *pfv.act > *priv->next_backtrack)) priv->next_backtrack = pfv.act; } @@ -504,26 +647,17 @@ bool ModelChecker::process_thread_action(ModelAction *curr) break; } case THREAD_JOIN: { - Thread *waiting, *blocking; - waiting = get_thread(curr); - blocking = (Thread *)curr->get_location(); - if (!blocking->is_complete()) { - blocking->push_wait_list(curr); - scheduler->sleep(waiting); - } else { - do_complete_join(curr); - updated = true; /* trigger rel-seq checks */ - } + Thread *blocking = (Thread *)curr->get_location(); + ModelAction *act = get_last_action(blocking->get_id()); + curr->synchronize_with(act); + updated = true; /* trigger rel-seq checks */ break; } case THREAD_FINISH: { Thread *th = get_thread(curr); while (!th->wait_list_empty()) { ModelAction *act = th->pop_wait_list(); - Thread *wake = get_thread(act); - scheduler->wake(wake); - do_complete_join(act); - updated = true; /* trigger rel-seq checks */ + scheduler->wake(get_thread(act)); } th->complete(); updated = true; /* trigger rel-seq checks */ @@ -540,6 +674,76 @@ bool ModelChecker::process_thread_action(ModelAction *curr) return updated; } +/** + * @brief Process the current action for release sequence fixup activity + * + * Performs model-checker release sequence fixups for the current action, + * forcing a single pending release sequence to break (with a given, potential + * "loose" write) or to complete (i.e., synchronize). If a pending release + * sequence forms a complete release sequence, then we must perform the fixup + * synchronization, mo_graph additions, etc. + * + * @param curr The current action; must be a release sequence fixup action + * @param work_queue The work queue to which to add work items as they are + * generated + */ +void ModelChecker::process_relseq_fixup(ModelAction *curr, work_queue_t *work_queue) +{ + const ModelAction *write = curr->get_node()->get_relseq_break(); + struct release_seq *sequence = pending_rel_seqs->back(); + pending_rel_seqs->pop_back(); + ASSERT(sequence); + ModelAction *acquire = sequence->acquire; + const ModelAction *rf = sequence->rf; + const ModelAction *release = sequence->release; + ASSERT(acquire); + ASSERT(release); + ASSERT(rf); + ASSERT(release->same_thread(rf)); + + if (write == NULL) { + /** + * @todo Forcing a synchronization requires that we set + * modification order constraints. For instance, we can't allow + * a fixup sequence in which two separate read-acquire + * operations read from the same sequence, where the first one + * synchronizes and the other doesn't. Essentially, we can't + * allow any writes to insert themselves between 'release' and + * 'rf' + */ + + /* Must synchronize */ + if (!acquire->synchronize_with(release)) { + set_bad_synchronization(); + return; + } + /* Re-check all pending release sequences */ + work_queue->push_back(CheckRelSeqWorkEntry(NULL)); + /* Re-check act for mo_graph edges */ + work_queue->push_back(MOEdgeWorkEntry(acquire)); + + /* propagate synchronization to later actions */ + action_list_t::reverse_iterator rit = action_trace->rbegin(); + for (; (*rit) != acquire; rit++) { + ModelAction *propagate = *rit; + if (acquire->happens_before(propagate)) { + propagate->synchronize_with(acquire); + /* Re-check 'propagate' for mo_graph edges */ + work_queue->push_back(MOEdgeWorkEntry(propagate)); + } + } + } else { + /* Break release sequence with new edges: + * release --mo--> write --mo--> rf */ + mo_graph->addEdge(release, write); + mo_graph->addEdge(write, rf); + } + + /* See if we have realized a data race */ + if (checkDataRaces()) + set_assert(); +} + /** * Initialize the current action by performing one or more of the following * actions, as appropriate: merging RMWR and RMWC/RMW actions, stepping forward @@ -547,41 +751,46 @@ bool ModelChecker::process_thread_action(ModelAction *curr) * initializing clock vectors, and computing the promises to fulfill. * * @param curr The current action, as passed from the user context; may be - * freed/invalidated after the execution of this function - * @return The current action, as processed by the ModelChecker. Is only the - * same as the parameter @a curr if this is a newly-explored action. + * freed/invalidated after the execution of this function, with a different + * action "returned" its place (pass-by-reference) + * @return True if curr is a newly-explored action; false otherwise */ -ModelAction * ModelChecker::initialize_curr_action(ModelAction *curr) +bool ModelChecker::initialize_curr_action(ModelAction **curr) { ModelAction *newcurr; - if (curr->is_rmwc() || curr->is_rmw()) { - newcurr = process_rmw(curr); - delete curr; + if ((*curr)->is_rmwc() || (*curr)->is_rmw()) { + newcurr = process_rmw(*curr); + delete *curr; if (newcurr->is_rmw()) compute_promises(newcurr); - return newcurr; + + *curr = newcurr; + return false; } - curr->set_seq_number(get_next_seq_num()); + (*curr)->set_seq_number(get_next_seq_num()); - newcurr = node_stack->explore_action(curr, scheduler->get_enabled()); + newcurr = node_stack->explore_action(*curr, scheduler->get_enabled()); if (newcurr) { /* First restore type and order in case of RMW operation */ - if (curr->is_rmwr()) - newcurr->copy_typeandorder(curr); + if ((*curr)->is_rmwr()) + newcurr->copy_typeandorder(*curr); - ASSERT(curr->get_location() == newcurr->get_location()); - newcurr->copy_from_new(curr); + ASSERT((*curr)->get_location() == newcurr->get_location()); + newcurr->copy_from_new(*curr); /* Discard duplicate ModelAction; use action from NodeStack */ - delete curr; + delete *curr; /* Always compute new clock vector */ newcurr->create_cv(get_parent_action(newcurr->get_tid())); + + *curr = newcurr; + return false; /* Action was explored previously */ } else { - newcurr = curr; + newcurr = *curr; /* Always compute new clock vector */ newcurr->create_cv(get_parent_action(newcurr->get_tid())); @@ -591,14 +800,24 @@ ModelAction * ModelChecker::initialize_curr_action(ModelAction *curr) */ if (newcurr->is_write()) compute_promises(newcurr); + else if (newcurr->is_relseq_fixup()) + compute_relseq_breakwrites(newcurr); + else if (newcurr->is_wait()) + newcurr->get_node()->set_misc_max(2); + else if (newcurr->is_notify_one()) { + newcurr->get_node()->set_misc_max(condvar_waiters_map->get_safe_ptr(newcurr->get_location())->size()); + } + return true; /* This was a new ModelAction */ } - return newcurr; } /** - * This method checks whether a model action is enabled at the given point. - * At this point, it checks whether a lock operation would be successful at this point. - * If not, it puts the thread in a waiter list. + * @brief Check whether a model action is enabled. + * + * Checks whether a lock or join operation would be successful (i.e., is the + * lock already locked, or is the joined thread already complete). If not, put + * the action in a waiter list. + * * @param curr is the ModelAction to check whether it is enabled. * @return a bool that indicates whether the action is enabled. */ @@ -611,6 +830,12 @@ bool ModelChecker::check_action_enabled(ModelAction *curr) { lock_waiters_map->get_safe_ptr(curr->get_location())->push_back(curr); return false; } + } else if (curr->get_type() == THREAD_JOIN) { + Thread *blocking = (Thread *)curr->get_location(); + if (!blocking->is_complete()) { + blocking->push_wait_list(curr); + return false; + } } return true; @@ -631,31 +856,30 @@ bool ModelChecker::check_action_enabled(ModelAction *curr) { Thread * ModelChecker::check_current_action(ModelAction *curr) { ASSERT(curr); - bool second_part_of_rmw = curr->is_rmwc() || curr->is_rmw(); if (!check_action_enabled(curr)) { /* Make the execution look like we chose to run this action - * much later, when a lock is actually available to release */ + * much later, when a lock/join can succeed */ get_current_thread()->set_pending(curr); scheduler->sleep(get_current_thread()); return get_next_thread(NULL); } - ModelAction *newcurr = initialize_curr_action(curr); + bool newly_explored = initialize_curr_action(&curr); + + wake_up_sleeping_actions(curr); /* Add the action to lists before any other model-checking tasks */ if (!second_part_of_rmw) - add_action_to_lists(newcurr); + add_action_to_lists(curr); /* Build may_read_from set for newly-created actions */ - if (curr == newcurr && curr->is_read()) + if (newly_explored && curr->is_read()) build_reads_from_past(curr); - curr = newcurr; /* Initialize work_queue with the "current action" work */ work_queue_t work_queue(1, CheckCurrWorkEntry(curr)); - while (!work_queue.empty()) { WorkQueueEntry work = work_queue.front(); work_queue.pop_front(); @@ -678,6 +902,9 @@ Thread * ModelChecker::check_current_action(ModelAction *curr) if (act->is_mutex_op() && process_mutex(act)) update_all = true; + if (act->is_relseq_fixup()) + process_relseq_fixup(curr, &work_queue); + if (update_all) work_queue.push_back(CheckRelSeqWorkEntry(NULL)); else if (update) @@ -714,33 +941,20 @@ Thread * ModelChecker::check_current_action(ModelAction *curr) } check_curr_backtracking(curr); - set_backtracking(curr); - return get_next_thread(curr); } -/** - * Complete a THREAD_JOIN operation, by synchronizing with the THREAD_FINISH - * operation from the Thread it is joining with. Must be called after the - * completion of the Thread in question. - * @param join The THREAD_JOIN action - */ -void ModelChecker::do_complete_join(ModelAction *join) -{ - Thread *blocking = (Thread *)join->get_location(); - ModelAction *act = get_last_action(blocking->get_id()); - join->synchronize_with(act); -} - void ModelChecker::check_curr_backtracking(ModelAction * curr) { Node *currnode = curr->get_node(); Node *parnode = currnode->get_parent(); if ((!parnode->backtrack_empty() || + !currnode->misc_empty() || !currnode->read_from_empty() || !currnode->future_value_empty() || - !currnode->promise_empty()) + !currnode->promise_empty() || + !currnode->relseq_break_empty()) && (!priv->next_backtrack || *curr > *priv->next_backtrack)) { priv->next_backtrack = curr; @@ -760,7 +974,7 @@ bool ModelChecker::promises_expired() { /** @return whether the current partial trace must be a prefix of a * feasible trace. */ bool ModelChecker::isfeasibleprefix() { - return promises->size() == 0 && pending_rel_seqs->size() == 0; + return promises->size() == 0 && pending_rel_seqs->size() == 0 && isfeasible(); } /** @return whether the current partial trace is feasible. */ @@ -883,7 +1097,7 @@ void ModelChecker::check_recency(ModelAction *curr, const ModelAction *rf) { ModelAction *act=*rit; bool foundvalue = false; for (int j = 0; jget_node()->get_read_from_size(); j++) { - if (act->get_node()->get_read_from_at(i)==write) { + if (act->get_node()->get_read_from_at(j)==write) { foundvalue = true; break; } @@ -1122,12 +1336,16 @@ bool ModelChecker::w_modification_order(ModelAction *curr) (3) cannot synchronize with us (4) is in a different thread => - that read could potentially read from our write. + that read could potentially read from our write. Note that + these checks are overly conservative at this point, we'll + do more checks before actually removing the + pendingfuturevalue. + */ if (thin_air_constraint_may_allow(curr, act)) { if (isfeasible() || (curr->is_rmw() && act->is_rmw() && curr->get_reads_from() == act->get_reads_from() && isfeasibleotherthanRMW())) { - struct PendingFutureValue pfv = {curr->get_value(),curr->get_seq_number()+params.maxfuturedelay,act}; + struct PendingFutureValue pfv = {curr,act}; futurevalues->push_back(pfv); } } @@ -1159,6 +1377,44 @@ bool ModelChecker::thin_air_constraint_may_allow(const ModelAction * writer, con return true; } +/** + * Arbitrary reads from the future are not allowed. Section 29.3 part 9 places + * some constraints. This method checks one the following constraint (others + * require compiler support): + * + * If X --hb-> Y --mo-> Z, then X should not read from Z. + */ +bool ModelChecker::mo_may_allow(const ModelAction *writer, const ModelAction *reader) +{ + std::vector *thrd_lists = obj_thrd_map->get_safe_ptr(reader->get_location()); + unsigned int i; + + /* Iterate over all threads */ + for (i = 0; i < thrd_lists->size(); i++) { + const ModelAction *write_after_read = NULL; + + /* Iterate over actions in thread, starting from most recent */ + action_list_t *list = &(*thrd_lists)[i]; + action_list_t::reverse_iterator rit; + for (rit = list->rbegin(); rit != list->rend(); rit++) { + ModelAction *act = *rit; + + if (!reader->happens_before(act)) + break; + else if (act->is_write()) + write_after_read = act; + else if (act->is_read()&&act->get_reads_from()!=NULL) { + write_after_read = act->get_reads_from(); + } + } + + if (write_after_read && write_after_read!=writer && mo_graph->checkReachable(write_after_read, writer)) + return false; + } + + return true; +} + /** * Finds the head(s) of the release sequence(s) containing a given ModelAction. * The ModelAction under consideration is expected to be taking part in @@ -1171,7 +1427,6 @@ bool ModelChecker::thin_air_constraint_may_allow(const ModelAction * writer, con * "returns" two pieces of data: a pass-by-reference vector of @a release_heads * and a boolean representing certainty. * - * @todo Finish lazy updating, when promises are fulfilled in the future * @param rf The action that might be part of a release sequence. Must be a * write. * @param release_heads A pass-by-reference style return parameter. After @@ -1258,10 +1513,14 @@ bool ModelChecker::release_seq_heads(const ModelAction *rf, bool future_ordered = false; ModelAction *last = get_last_action(int_to_id(i)); - if (last && (rf->happens_before(last) || - get_thread(int_to_id(i))->is_complete())) + Thread *th = get_thread(int_to_id(i)); + if ((last && rf->happens_before(last)) || + !scheduler->is_enabled(th) || + th->is_complete()) future_ordered = true; + ASSERT(!th->is_model_thread() || future_ordered); + for (rit = list->rbegin(); rit != list->rend(); rit++) { const ModelAction *act = *rit; /* Reach synchronization -> this thread is complete */ @@ -1272,8 +1531,8 @@ bool ModelChecker::release_seq_heads(const ModelAction *rf, continue; } - /* Only writes can break release sequences */ - if (!act->is_write()) + /* Only non-RMW writes can break release sequences */ + if (!act->is_write() || act->is_rmw()) continue; /* Check modification order */ @@ -1350,7 +1609,7 @@ void ModelChecker::get_release_seq_heads(ModelAction *act, rel_heads_list_t *rel bool ModelChecker::resolve_release_sequences(void *location, work_queue_t *work_queue) { bool updated = false; - std::vector::iterator it = pending_rel_seqs->begin(); + std::vector< struct release_seq *, SnapshotAlloc >::iterator it = pending_rel_seqs->begin(); while (it != pending_rel_seqs->end()) { struct release_seq *pending = *it; ModelAction *act = pending->acquire; @@ -1429,6 +1688,20 @@ void ModelChecker::add_action_to_lists(ModelAction *act) if ((int)thrd_last_action->size() <= tid) thrd_last_action->resize(get_num_threads()); (*thrd_last_action)[tid] = act; + + if (act->is_wait()) { + void *mutex_loc=(void *) act->get_value(); + obj_map->get_safe_ptr(mutex_loc)->push_back(act); + + std::vector *vec = obj_thrd_map->get_safe_ptr(mutex_loc); + if (tid >= (int)vec->size()) + vec->resize(priv->next_thread_id); + (*vec)[tid].push_back(act); + + if ((int)thrd_last_action->size() <= tid) + thrd_last_action->resize(get_num_threads()); + (*thrd_last_action)[tid] = act; + } } /** @@ -1480,7 +1753,7 @@ ModelAction * ModelChecker::get_last_unlock(ModelAction *curr) const /* Find: max({i in dom(S) | isUnlock(t_i) && samevar(t_i, t)}) */ action_list_t::reverse_iterator rit; for (rit = list->rbegin(); rit != list->rend(); rit++) - if ((*rit)->is_unlock()) + if ((*rit)->is_unlock() || (*rit)->is_wait()) return *rit; return NULL; } @@ -1512,7 +1785,7 @@ ClockVector * ModelChecker::get_cv(thread_id_t tid) bool ModelChecker::resolve_promises(ModelAction *write) { bool resolved = false; - std::vector threads_to_check; + std::vector< thread_id_t, ModelAlloc > threads_to_check; for (unsigned int i = 0, promise_index = 0; promise_index < promises->size(); i++) { Promise *promise = (*promises)[promise_index]; @@ -1564,8 +1837,9 @@ void ModelChecker::compute_promises(ModelAction *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); + curr->get_node()->set_promise(i, act->is_rmw()); } } } @@ -1587,6 +1861,16 @@ void ModelChecker::check_promises(thread_id_t tid, ClockVector *old_cv, ClockVec } } +void ModelChecker::check_promises_thread_disabled() { + for (unsigned int i = 0; i < promises->size(); i++) { + Promise *promise = (*promises)[i]; + if (promise->check_promise()) { + failed_promise = true; + return; + } + } +} + /** Checks promises in response to addition to modification order for threads. * Definitions: * pthread is the thread that performed the read that created the promise @@ -1630,6 +1914,11 @@ void ModelChecker::mo_check_promises(thread_id_t tid, const ModelAction *write) //do we have a pwrite for the promise, if not, set it if (promise->get_write() == NULL ) { promise->set_write(write); + //The pwrite cannot happen before the promise + if (write->happens_before(act) && (write != act)) { + failed_promise = true; + return; + } } if (mo_graph->checkPromise(write, promise)) { failed_promise = true; @@ -1641,7 +1930,7 @@ void ModelChecker::mo_check_promises(thread_id_t tid, const ModelAction *write) if (promise->has_sync_thread(tid)) continue; - if (mo_graph->checkReachable(promise->get_write(), write)) { + if (promise->get_write()&&mo_graph->checkReachable(promise->get_write(), write)) { if (promise->increment_threads(tid)) { failed_promise = true; return; @@ -1650,6 +1939,29 @@ void ModelChecker::mo_check_promises(thread_id_t tid, const ModelAction *write) } } +/** + * Compute the set of writes that may break the current pending release + * sequence. This information is extracted from previou release sequence + * calculations. + * + * @param curr The current ModelAction. Must be a release sequence fixup + * action. + */ +void ModelChecker::compute_relseq_breakwrites(ModelAction *curr) +{ + if (pending_rel_seqs->empty()) + return; + + struct release_seq *pending = pending_rel_seqs->back(); + for (unsigned int i = 0; i < pending->writes.size(); i++) { + const ModelAction *write = pending->writes[i]; + curr->get_node()->add_relseq_break(write); + } + + /* NULL means don't break the sequence; just synchronize */ + curr->get_node()->add_relseq_break(NULL); +} + /** * 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" @@ -1695,7 +2007,12 @@ void ModelChecker::build_reads_from_past(ModelAction *curr) act->print(); curr->print(); } - curr->get_node()->add_read_from(act); + + if (curr->get_sleep_flag() && ! curr->is_seqcst()) { + if (sleep_can_read_from(curr, act)) + curr->get_node()->add_read_from(act); + } else + curr->get_node()->add_read_from(act); } /* Include at most one act per-thread that "happens before" curr */ @@ -1709,6 +2026,7 @@ void ModelChecker::build_reads_from_past(ModelAction *curr) if (!initialized) { /** @todo Need a more informative way of reporting errors. */ printf("ERROR: may read from uninitialized atomic\n"); + set_assert(); } if (DBG_ENABLED() || !initialized) { @@ -1718,8 +2036,22 @@ void ModelChecker::build_reads_from_past(ModelAction *curr) curr->get_node()->print_may_read_from(); printf("End printing may_read_from\n"); } +} - ASSERT(initialized); +bool ModelChecker::sleep_can_read_from(ModelAction * curr, const ModelAction *write) { + while(true) { + Node *prevnode=write->get_node()->get_parent(); + + bool thread_sleep=prevnode->enabled_status(curr->get_tid())==THREAD_SLEEP_SET; + if (write->is_release()&&thread_sleep) + return true; + if (!write->is_rmw()) { + return false; + } + if (write->get_reads_from()==NULL) + return true; + write=write->get_reads_from(); + } } static void print_list(action_list_t *list) @@ -1728,10 +2060,13 @@ static void print_list(action_list_t *list) printf("---------------------------------------------------------------------\n"); printf("Trace:\n"); - + unsigned int hash=0; + for (it = list->begin(); it != list->end(); it++) { (*it)->print(); + hash=hash^(hash<<3)^((*it)->hash()); } + printf("HASH %u\n", hash); printf("---------------------------------------------------------------------\n"); } @@ -1853,7 +2188,7 @@ bool ModelChecker::take_step() { if (has_asserted()) return false; - Thread *curr = thread_current(); + Thread *curr = priv->current_action ? get_thread(priv->current_action) : NULL; if (curr) { if (curr->get_state() == THREAD_READY) { ASSERT(priv->current_action); @@ -1873,9 +2208,35 @@ bool ModelChecker::take_step() { if (!isfeasible()) return false; + if (params.bound != 0) { + if (priv->used_sequence_numbers > params.bound) { + return false; + } + } + DEBUG("(%d, %d)\n", curr ? id_to_int(curr->get_id()) : -1, next ? id_to_int(next->get_id()) : -1); + /* + * Launch end-of-execution release sequence fixups only when there are: + * + * (1) no more user threads to run (or when execution replay chooses + * the 'model_thread') + * (2) pending release sequences + * (3) pending assertions (i.e., data races) + * (4) no pending promises + */ + if (!pending_rel_seqs->empty() && (!next || next->is_model_thread()) && + isfinalfeasible() && !unrealizedraces.empty()) { + printf("*** WARNING: release sequence fixup action (%zu pending release seuqences) ***\n", + pending_rel_seqs->size()); + ModelAction *fixup = new ModelAction(MODEL_FIXUP_RELSEQ, + std::memory_order_seq_cst, NULL, VALUE_NONE, + model_thread); + set_current_action(fixup); + return true; + } + /* next == NULL -> don't take any more steps */ if (!next) return false;