X-Git-Url: http://plrg.eecs.uci.edu/git/?p=c11tester.git;a=blobdiff_plain;f=model.cc;h=c4bc693ef5560f646684b3a2cb002e685f4be848;hp=aec05ffe4bc6a46c0bf00d2d252d8bfa2025613e;hb=99ca0039c04d8c3dc000f7d3899d1d81564bc168;hpb=d1930060e483b841f0a9c35c5041035dbdf6de4a diff --git a/model.cc b/model.cc index aec05ffe..c4bc693e 100644 --- a/model.cc +++ b/model.cc @@ -20,10 +20,10 @@ ModelChecker *model; /** @brief Constructor */ ModelChecker::ModelChecker(struct model_params params) : /* Initialize default scheduler */ + params(params), scheduler(new Scheduler()), num_executions(0), num_feasible_executions(0), - params(params), diverge(NULL), action_trace(new action_list_t()), thread_map(new HashTable()), @@ -32,20 +32,19 @@ ModelChecker::ModelChecker(struct model_params params) : obj_thrd_map(new HashTable, uintptr_t, 4 >()), promises(new std::vector()), futurevalues(new std::vector()), - lazy_sync_with_release(new HashTable()), + pending_acq_rel_seq(new std::vector()), thrd_last_action(new std::vector(1)), node_stack(new NodeStack()), mo_graph(new CycleGraph()), failed_promise(false), too_many_reads(false), - asserted(false) + asserted(false), + bad_synchronization(false) { /* Allocate this "size" on the snapshotting heap */ 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; - - lazy_sync_size = &priv->lazy_sync_size; } /** @brief Destructor */ @@ -64,7 +63,7 @@ ModelChecker::~ModelChecker() delete (*promises)[i]; delete promises; - delete lazy_sync_with_release; + delete pending_acq_rel_seq; delete thrd_last_action; delete node_stack; @@ -82,23 +81,24 @@ void ModelChecker::reset_to_initial_state() node_stack->reset_execution(); failed_promise = false; too_many_reads = false; + bad_synchronization = false; reset_asserted(); snapshotObject->backTrackBeforeStep(0); } -/** @returns a thread ID for a new Thread */ +/** @return a thread ID for a new Thread */ thread_id_t ModelChecker::get_next_id() { return priv->next_thread_id++; } -/** @returns the number of user threads created during this execution */ +/** @return the number of user threads created during this execution */ int ModelChecker::get_num_threads() { return priv->next_thread_id; } -/** @returns a sequence number for a new ModelAction */ +/** @return a sequence number for a new ModelAction */ modelclock_t ModelChecker::get_next_seq_num() { return ++priv->used_sequence_numbers; @@ -200,9 +200,10 @@ bool ModelChecker::next_execution() ModelAction * ModelChecker::get_last_conflict(ModelAction *act) { - action_type type = act->get_type(); - - if (type==ATOMIC_READ||type==ATOMIC_WRITE||type==ATOMIC_RMW) { + switch (act->get_type()) { + case ATOMIC_READ: + case ATOMIC_WRITE: + case ATOMIC_RMW: { /* 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; @@ -211,59 +212,96 @@ ModelAction * ModelChecker::get_last_conflict(ModelAction *act) if (act->is_synchronizing(prev)) return prev; } - } else if (type==ATOMIC_LOCK||type==ATOMIC_TRYLOCK) { + break; + } + case ATOMIC_LOCK: + case ATOMIC_TRYLOCK: { /* 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 (prev->is_success_lock()) + if (act->is_conflicting_lock(prev)) return prev; } - } else if (type==ATOMIC_UNLOCK) { + break; + } + case ATOMIC_UNLOCK: { /* 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 (prev->is_failed_trylock()) + if (!act->same_thread(prev)&&prev->is_failed_trylock()) return prev; } + break; + } + default: + break; } return NULL; } +/** This method find backtracking points where we should try to + * reorder the parameter ModelAction against. + * + * @param the ModelAction to find backtracking points for. + */ void ModelChecker::set_backtracking(ModelAction *act) { - ModelAction *prev; - Node *node; Thread *t = get_thread(act); - - prev = get_last_conflict(act); + ModelAction * prev = get_last_conflict(act); if (prev == NULL) return; - node = prev->get_node()->get_parent(); + Node * node = prev->get_node()->get_parent(); - while (!node->is_enabled(t)) - t = t->get_parent(); + int low_tid, high_tid; + if (node->is_enabled(t)) { + low_tid = id_to_int(act->get_tid()); + high_tid = low_tid+1; + } else { + low_tid = 0; + high_tid = get_num_threads(); + } - /* Check if this has been explored already */ - if (node->has_been_explored(t->get_id())) - return; + for(int i = low_tid; i < high_tid; i++) { + thread_id_t tid = int_to_id(i); + if (!node->is_enabled(tid)) + continue; - /* Cache the latest backtracking point */ - if (!priv->next_backtrack || *prev > *priv->next_backtrack) - priv->next_backtrack = prev; + /* Check if this has been explored already */ + if (node->has_been_explored(tid)) + continue; - /* If this is a new backtracking point, mark the tree */ - if (!node->set_backtrack(t->get_id())) - return; - DEBUG("Setting backtrack: conflict = %d, instead tid = %d\n", - prev->get_tid(), t->get_id()); - if (DBG_ENABLED()) { - prev->print(); - act->print(); + /* See if fairness allows */ + if (model->params.fairwindow != 0 && !node->has_priority(tid)) { + bool unfair=false; + for(int t=0;tget_num_threads();t++) { + thread_id_t tother=int_to_id(t); + if (node->is_enabled(tother) && node->has_priority(tother)) { + unfair=true; + break; + } + } + if (unfair) + continue; + } + + /* Cache the latest backtracking point */ + if (!priv->next_backtrack || *prev > *priv->next_backtrack) + priv->next_backtrack = prev; + + /* If this is a new backtracking point, mark the tree */ + if (!node->set_backtrack(tid)) + continue; + DEBUG("Setting backtrack: conflict = %d, instead tid = %d\n", + prev->get_tid(), t->get_id()); + if (DBG_ENABLED()) { + prev->print(); + act->print(); + } } } @@ -298,7 +336,7 @@ bool ModelChecker::process_read(ModelAction *curr, bool second_part_of_rmw) bool r_status = false; if (!second_part_of_rmw) { - check_recency(curr); + check_recency(curr, reads_from); r_status = r_modification_order(curr, reads_from); } @@ -325,12 +363,28 @@ bool ModelChecker::process_read(ModelAction *curr, bool second_part_of_rmw) } } -void ModelChecker::process_mutex(ModelAction *curr) { - std::mutex * mutex=(std::mutex *) curr->get_location(); - struct std::mutex_state * state=mutex->get_state(); - switch(curr->get_type()) { +/** + * Processes a lock, trylock, or unlock model action. @param curr is + * the read model action to process. + * + * The try lock operation checks whether the lock is taken. If not, + * it falls to the normal lock operation case. If so, it returns + * fail. + * + * The lock operation has already been checked that it is enabled, so + * it just grabs the lock and synchronizes with the previous unlock. + * + * The unlock operation has to re-enable all of the threads that are + * waiting on the lock. + * + * @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(); + switch (curr->get_type()) { case ATOMIC_TRYLOCK: { - bool success=!state->islocked; + bool success = !state->islocked; curr->set_try_lock(success); if (!success) { get_thread(curr)->set_return_value(0); @@ -340,25 +394,27 @@ void ModelChecker::process_mutex(ModelAction *curr) { } //otherwise fall into the lock case case ATOMIC_LOCK: { - if (curr->get_cv()->getClock(state->alloc_tid)<=state->alloc_clock) { + if (curr->get_cv()->getClock(state->alloc_tid) <= state->alloc_clock) { printf("Lock access before initialization\n"); set_assert(); } - state->islocked=true; - ModelAction *unlock=get_last_unlock(curr); + state->islocked = true; + ModelAction *unlock = get_last_unlock(curr); //synchronize with the previous unlock statement - if ( unlock != NULL ) + if (unlock != NULL) { curr->synchronize_with(unlock); + return true; + } break; } case ATOMIC_UNLOCK: { //unlock the lock - state->islocked=false; + state->islocked = false; //wake up the other threads - action_list_t * waiters = lock_waiters_map->get_safe_ptr(curr->get_location()); + action_list_t *waiters = lock_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++) { - add_thread(get_thread((*rit)->get_tid())); + for (action_list_t::iterator rit = waiters->begin(); rit != waiters->end(); rit++) { + scheduler->add_thread(get_thread((*rit)->get_tid())); } waiters->clear(); break; @@ -366,9 +422,9 @@ void ModelChecker::process_mutex(ModelAction *curr) { default: ASSERT(0); } + return false; } - /** * Process a write ModelAction * @param curr The ModelAction to process @@ -380,7 +436,7 @@ bool ModelChecker::process_write(ModelAction *curr) bool updated_promises = resolve_promises(curr); if (promises->size() == 0) { - for (unsigned int i = 0; isize(); i++) { + 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) && (!priv->next_backtrack || *pfv.act > *priv->next_backtrack)) @@ -394,6 +450,63 @@ bool ModelChecker::process_write(ModelAction *curr) return updated_mod_order || updated_promises; } +/** + * @brief Process the current action for thread-related activity + * + * Performs current-action processing for a THREAD_* ModelAction. Proccesses + * may include setting Thread status, completing THREAD_FINISH/THREAD_JOIN + * synchronization, etc. This function is a no-op for non-THREAD actions + * (e.g., ATOMIC_{READ,WRITE,RMW,LOCK}, etc.) + * + * @param curr The current action + * @return True if synchronization was updated + */ +bool ModelChecker::process_thread_action(ModelAction *curr) +{ + bool synchronized = false; + + switch (curr->get_type()) { + case THREAD_CREATE: { + Thread *th = (Thread *)curr->get_location(); + th->set_creation(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); + synchronized = true; + } + 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); + synchronized = true; + } + th->complete(); + break; + } + case THREAD_START: { + check_promises(NULL, curr->get_cv()); + break; + } + default: + break; + } + + return synchronized; +} + /** * Initialize the current action by performing one or more of the following * actions, as appropriate: merging RMWR and RMWC/RMW actions, stepping forward @@ -412,7 +525,9 @@ ModelAction * ModelChecker::initialize_curr_action(ModelAction *curr) if (curr->is_rmwc() || curr->is_rmw()) { newcurr = process_rmw(curr); delete curr; - compute_promises(newcurr); + + if (newcurr->is_rmw()) + compute_promises(newcurr); return newcurr; } @@ -422,14 +537,13 @@ ModelAction * ModelChecker::initialize_curr_action(ModelAction *curr) if (curr->is_rmwr()) newcurr->copy_typeandorder(curr); - ASSERT(curr->get_location()==newcurr->get_location()); + ASSERT(curr->get_location() == newcurr->get_location()); + newcurr->copy_from_new(curr); /* Discard duplicate ModelAction; use action from NodeStack */ delete curr; - /* If we have diverged, we need to reset the clock vector. */ - if (diverge == NULL) - newcurr->create_cv(get_parent_action(newcurr->get_tid())); + newcurr->create_cv(get_parent_action(newcurr->get_tid())); } else { newcurr = curr; /* @@ -443,9 +557,16 @@ ModelAction * ModelChecker::initialize_curr_action(ModelAction *curr) 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. + * @param curr is the ModelAction to check whether it is enabled. + * @return a bool that indicates whether the action is enabled. + */ bool ModelChecker::check_action_enabled(ModelAction *curr) { if (curr->is_lock()) { - std::mutex * lock=(std::mutex *) curr->get_location(); + std::mutex * lock = (std::mutex *)curr->get_location(); struct std::mutex_state * state = lock->get_state(); if (state->islocked) { //Stick the action in the appropriate waiting queue @@ -476,8 +597,8 @@ Thread * ModelChecker::check_current_action(ModelAction *curr) bool second_part_of_rmw = curr->is_rmwc() || curr->is_rmw(); if (!check_action_enabled(curr)) { - //we'll make the execution look like we chose to run this action - //much later...when a lock is actually available to relese + /* Make the execution look like we chose to run this action + * much later, when a lock is actually available to release */ get_current_thread()->set_pending(curr); remove_thread(get_current_thread()); return get_next_thread(NULL); @@ -494,53 +615,7 @@ Thread * ModelChecker::check_current_action(ModelAction *curr) build_reads_from_past(curr); curr = newcurr; - /* Add the action to lists before any other model-checking tasks */ - if (!second_part_of_rmw) - add_action_to_lists(newcurr); - - /* Build may_read_from set for newly-created actions */ - if (curr == newcurr && curr->is_read()) - build_reads_from_past(curr); - curr = newcurr; - - /* Thread specific actions */ - switch (curr->get_type()) { - case THREAD_CREATE: { - Thread *th = (Thread *)curr->get_location(); - th->set_creation(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); - } - 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); - } - th->complete(); - break; - } - case THREAD_START: { - check_promises(NULL, curr->get_cv()); - break; - } - default: - break; - } - + /* Initialize work_queue with the "current action" work */ work_queue_t work_queue(1, CheckCurrWorkEntry(curr)); while (!work_queue.empty()) { @@ -550,17 +625,24 @@ Thread * ModelChecker::check_current_action(ModelAction *curr) switch (work.type) { case WORK_CHECK_CURR_ACTION: { ModelAction *act = work.action; - bool updated = false; + bool update = false; /* update this location's release seq's */ + bool update_all = false; /* update all release seq's */ + + if (process_thread_action(curr)) + update_all = true; + if (act->is_read() && process_read(act, second_part_of_rmw)) - updated = true; + update = true; if (act->is_write() && process_write(act)) - updated = true; + update = true; - if (act->is_mutex_op()) - process_mutex(act); + if (act->is_mutex_op() && process_mutex(act)) + update_all = true; - if (updated) + if (update_all) + work_queue.push_back(CheckRelSeqWorkEntry(NULL)); + else if (update) work_queue.push_back(CheckRelSeqWorkEntry(act->get_location())); break; } @@ -580,6 +662,7 @@ Thread * ModelChecker::check_current_action(ModelAction *curr) if (w_modification_order(act)) updated = true; } + mo_graph->commitChanges(); if (updated) work_queue.push_back(CheckRelSeqWorkEntry(act->get_location())); @@ -635,18 +718,21 @@ bool ModelChecker::promises_expired() { return false; } -/** @returns whether the current partial trace must be a prefix of a +/** @return whether the current partial trace must be a prefix of a * feasible trace. */ bool ModelChecker::isfeasibleprefix() { - return promises->size() == 0 && *lazy_sync_size == 0; + return promises->size() == 0 && pending_acq_rel_seq->size() == 0; } -/** @returns whether the current partial trace is feasible. */ +/** @return whether the current partial trace is feasible. */ bool ModelChecker::isfeasible() { + if (DBG_ENABLED() && mo_graph->checkForRMWViolation()) + DEBUG("Infeasible: RMW violation\n"); + return !mo_graph->checkForRMWViolation() && isfeasibleotherthanRMW(); } -/** @returns whether the current partial trace is feasible other than +/** @return whether the current partial trace is feasible other than * multiple RMW reading from the same store. */ bool ModelChecker::isfeasibleotherthanRMW() { if (DBG_ENABLED()) { @@ -656,10 +742,12 @@ bool ModelChecker::isfeasibleotherthanRMW() { DEBUG("Infeasible: failed promise\n"); if (too_many_reads) DEBUG("Infeasible: too many reads\n"); + if (bad_synchronization) + DEBUG("Infeasible: bad synchronization ordering\n"); if (promises_expired()) DEBUG("Infeasible: promises expired\n"); } - return !mo_graph->checkForCycles() && !failed_promise && !too_many_reads && !promises_expired(); + return !mo_graph->checkForCycles() && !failed_promise && !too_many_reads && !bad_synchronization && !promises_expired(); } /** Returns whether the current completed trace is feasible. */ @@ -693,23 +781,21 @@ ModelAction * ModelChecker::process_rmw(ModelAction *act) { * * If so, we decide that the execution is no longer feasible. */ -void ModelChecker::check_recency(ModelAction *curr) { +void ModelChecker::check_recency(ModelAction *curr, const ModelAction *rf) { 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 (!isfeasible()) return; - std::vector *thrd_lists = obj_thrd_map->get_safe_ptr(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(); @@ -728,17 +814,18 @@ void ModelChecker::check_recency(ModelAction *curr) { ModelAction *act = *rit; if (!act->is_read()) return; - if (act->get_reads_from() != curr->get_reads_from()) + + if (act->get_reads_from() != rf) return; if (act->get_node()->get_read_from_size() <= 1) return; } - for (int i = 0; iget_node()->get_read_from_size(); i++) { //Get write const ModelAction * write = curr->get_node()->get_read_from_at(i); + //Need a different write - if (write==curr->get_reads_from()) + if (write==rf) continue; /* Test to see whether this is a feasible write to read from*/ @@ -778,7 +865,7 @@ void ModelChecker::check_recency(ModelAction *curr) { /** * Updates the mo_graph with the constraints imposed from the current - * read. + * read. * * Basic idea is the following: Go through each other thread and find * the lastest action that happened before our read. Two cases: @@ -837,7 +924,7 @@ bool ModelChecker::r_modification_order(ModelAction *curr, const ModelAction *rf * promises. The basic problem is that actions that occur after the * read curr could not property add items to the modification order * for our read. - * + * * So for each thread, we find the earliest item that happens after * the read curr. This is the item we have to fix up with additional * constraints. If that action is write, we add a MO edge between @@ -848,7 +935,6 @@ bool ModelChecker::r_modification_order(ModelAction *curr, const ModelAction *rf * @param rf is the write ModelAction that curr reads from. * */ - void ModelChecker::post_r_modification_order(ModelAction *curr, const ModelAction *rf) { std::vector *thrd_lists = obj_thrd_map->get_safe_ptr(curr->get_location()); @@ -862,10 +948,10 @@ void ModelChecker::post_r_modification_order(ModelAction *curr, const ModelActio action_list_t::reverse_iterator rit; ModelAction *lastact = NULL; - /* Find last action that happens after curr */ + /* Find last action that happens after curr that is either not curr or a rmw */ for (rit = list->rbegin(); rit != list->rend(); rit++) { ModelAction *act = *rit; - if (curr->happens_before(act)) { + if (curr->happens_before(act) && (curr != act || curr->is_rmw())) { lastact = act; } else break; @@ -873,12 +959,25 @@ void ModelChecker::post_r_modification_order(ModelAction *curr, const ModelActio /* Include at most one act per-thread that "happens before" curr */ if (lastact != NULL) { - if (lastact->is_read()) { + if (lastact==curr) { + //Case 1: The resolved read is a RMW, and we need to make sure + //that the write portion of the RMW mod order after rf + + mo_graph->addEdge(rf, lastact); + } else if (lastact->is_read()) { + //Case 2: The resolved read is a normal read and the next + //operation is a read, and we need to make sure the value read + //is mod ordered after rf + const ModelAction *postreadfrom = lastact->get_reads_from(); if (postreadfrom != NULL&&rf != postreadfrom) mo_graph->addEdge(rf, postreadfrom); - } else if (rf != lastact) { - mo_graph->addEdge(rf, lastact); + } else { + //Case 3: The resolved read is a normal read and the next + //operation is a write, and we need to make sure that the + //write is mod ordered after rf + if (lastact!=rf) + mo_graph->addEdge(rf, lastact); } break; } @@ -973,7 +1072,7 @@ bool ModelChecker::w_modification_order(ModelAction *curr) */ 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())) { + (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}; futurevalues->push_back(pfv); } @@ -988,7 +1087,6 @@ bool ModelChecker::w_modification_order(ModelAction *curr) /** Arbitrary reads from the future are not allowed. Section 29.3 * part 9 places some constraints. This method checks one result of constraint * constraint. Others require compiler support. */ - bool ModelChecker::thin_air_constraint_may_allow(const ModelAction * writer, const ModelAction *reader) { if (!writer->is_rmw()) return true; @@ -997,7 +1095,7 @@ bool ModelChecker::thin_air_constraint_may_allow(const ModelAction * writer, con return true; for (const ModelAction *search = writer->get_reads_from(); search != NULL; search = search->get_reads_from()) { - if (search==reader) + if (search == reader) return false; if (search->get_tid() == reader->get_tid() && search->happens_before(reader)) @@ -1030,24 +1128,36 @@ bool ModelChecker::thin_air_constraint_may_allow(const ModelAction * writer, con */ bool ModelChecker::release_seq_head(const ModelAction *rf, rel_heads_list_t *release_heads) const { - if (!rf) { - /* read from future: need to settle this later */ - return false; /* incomplete */ - } + /* Only check for release sequences if there are no cycles */ + if (mo_graph->checkForCycles()) + return false; - ASSERT(rf->is_write()); + while (rf) { + ASSERT(rf->is_write()); + + if (rf->is_release()) + release_heads->push_back(rf); + if (!rf->is_rmw()) + break; /* End of RMW chain */ - if (rf->is_release()) - release_heads->push_back(rf); - if (rf->is_rmw()) { - /* We need a RMW action that is both an acquire and release to stop */ /** @todo Need to be smarter here... In the linux lock * example, this will run to the beginning of the program for * every acquire. */ + /** @todo The way to be smarter here is to keep going until 1 + * thread has a release preceded by an acquire and you've seen + * both. */ + + /* acq_rel RMW is a sufficient stopping condition */ if (rf->is_acquire() && rf->is_release()) return true; /* complete */ - return release_seq_head(rf->get_reads_from(), release_heads); + + rf = rf->get_reads_from(); + }; + if (!rf) { + /* read from future: need to settle this later */ + return false; /* incomplete */ } + if (rf->is_release()) return true; /* complete */ @@ -1084,10 +1194,13 @@ bool ModelChecker::release_seq_head(const ModelAction *rf, rel_heads_list_t *rel * the release seq? */ bool future_ordered = false; + ModelAction *last = get_last_action(int_to_id(i)); + if (last && (rf->happens_before(last) || + last->get_type() == THREAD_FINISH)) + future_ordered = true; + for (rit = list->rbegin(); rit != list->rend(); rit++) { const ModelAction *act = *rit; - if (!act->is_write()) - continue; /* Reach synchronization -> this thread is complete */ if (act->happens_before(release)) break; @@ -1096,6 +1209,10 @@ bool ModelChecker::release_seq_head(const ModelAction *rf, rel_heads_list_t *rel continue; } + /* Only writes can break release sequences */ + if (!act->is_write()) + continue; + /* Check modification order */ if (mo_graph->checkReachable(rf, act)) { /* rf --mo--> act */ @@ -1140,10 +1257,7 @@ void ModelChecker::get_release_seq_heads(ModelAction *act, rel_heads_list_t *rel complete = release_seq_head(rf, release_heads); if (!complete) { /* add act to 'lazy checking' list */ - action_list_t *list; - list = lazy_sync_with_release->get_safe_ptr(act->get_location()); - list->push_back(act); - (*lazy_sync_size)++; + pending_acq_rel_seq->push_back(act); } } @@ -1154,7 +1268,7 @@ void ModelChecker::get_release_seq_heads(ModelAction *act, rel_heads_list_t *rel * modification order information is present at the time an action occurs. * * @param location The location/object that should be checked for release - * sequence resolutions + * sequence resolutions. A NULL value means to check all locations. * @param work_queue The work queue to which to add work items as they are * generated * @return True if any updates occurred (new synchronization, new mo_graph @@ -1162,23 +1276,27 @@ 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) { - action_list_t *list; - list = lazy_sync_with_release->getptr(location); - if (!list) - return false; - bool updated = false; - action_list_t::iterator it = list->begin(); - while (it != list->end()) { + std::vector::iterator it = pending_acq_rel_seq->begin(); + while (it != pending_acq_rel_seq->end()) { ModelAction *act = *it; + + /* Only resolve sequences on the given location, if provided */ + if (location && act->get_location() != location) { + it++; + continue; + } + const ModelAction *rf = act->get_reads_from(); rel_heads_list_t release_heads; bool complete; complete = release_seq_head(rf, &release_heads); for (unsigned int i = 0; i < release_heads.size(); i++) { if (!act->has_synchronized_with(release_heads[i])) { - updated = true; - act->synchronize_with(release_heads[i]); + if (act->synchronize_with(release_heads[i])) + updated = true; + else + set_bad_synchronization(); } } @@ -1187,9 +1305,9 @@ bool ModelChecker::resolve_release_sequences(void *location, work_queue_t *work_ work_queue->push_back(MOEdgeWorkEntry(act)); /* propagate synchronization to later actions */ - action_list_t::reverse_iterator it = action_trace->rbegin(); - while ((*it) != act) { - ModelAction *propagate = *it; + action_list_t::reverse_iterator rit = action_trace->rbegin(); + for (; (*rit) != act; rit++) { + ModelAction *propagate = *rit; if (act->happens_before(propagate)) { propagate->synchronize_with(act); /* Re-check 'propagate' for mo_graph edges */ @@ -1197,10 +1315,9 @@ bool ModelChecker::resolve_release_sequences(void *location, work_queue_t *work_ } } } - if (complete) { - it = list->erase(it); - (*lazy_sync_size)--; - } else + if (complete) + it = pending_acq_rel_seq->erase(it); + else it++; } @@ -1236,10 +1353,15 @@ void ModelChecker::add_action_to_lists(ModelAction *act) (*thrd_last_action)[tid] = act; } -ModelAction * ModelChecker::get_last_action(thread_id_t tid) +/** + * @brief Get the last action performed by a particular Thread + * @param tid The thread ID of the Thread in question + * @return The last action in the thread + */ +ModelAction * ModelChecker::get_last_action(thread_id_t tid) const { - int threadid=id_to_int(tid); - if (threadid<(int)thrd_last_action->size()) + int threadid = id_to_int(tid); + if (threadid < (int)thrd_last_action->size()) return (*thrd_last_action)[id_to_int(tid)]; else return NULL; @@ -1253,7 +1375,7 @@ ModelAction * ModelChecker::get_last_action(thread_id_t tid) * check * @return The last seq_cst write */ -ModelAction * ModelChecker::get_last_seq_cst(ModelAction *curr) +ModelAction * ModelChecker::get_last_seq_cst(ModelAction *curr) const { void *location = curr->get_location(); action_list_t *list = obj_map->get_safe_ptr(location); @@ -1265,11 +1387,19 @@ ModelAction * ModelChecker::get_last_seq_cst(ModelAction *curr) return NULL; } -ModelAction * ModelChecker::get_last_unlock(ModelAction *curr) +/** + * Gets the last unlock operation performed on a particular mutex (i.e., memory + * location). This function identifies the mutex according to the current + * action, which is presumed to perform on the same mutex. + * @param curr The current ModelAction; also denotes the object location to + * check + * @return The last unlock operation + */ +ModelAction * ModelChecker::get_last_unlock(ModelAction *curr) const { void *location = curr->get_location(); action_list_t *list = obj_map->get_safe_ptr(location); - /* Find: max({i in dom(S) | seq_cst(t_i) && isWrite(t_i) && samevar(t_i, t)}) */ + /* 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()) @@ -1309,16 +1439,19 @@ bool ModelChecker::resolve_promises(ModelAction *write) Promise *promise = (*promises)[promise_index]; if (write->get_node()->get_promise(i)) { ModelAction *read = promise->get_action(); - read->read_from(write); if (read->is_rmw()) { mo_graph->addRMWEdge(write, read); } + read->read_from(write); //First fix up the modification order for actions that happened //before the read r_modification_order(read, write); //Next fix up the modification order for actions that happened //after the read. post_r_modification_order(read, write); + //Make sure the promise's value matches the write's value + ASSERT(promise->get_value() == write->get_value()); + promises->erase(promises->begin() + promise_index); resolved = true; } else @@ -1406,7 +1539,7 @@ void ModelChecker::build_reads_from_past(ModelAction *curr) continue; /* Don't consider more than one seq_cst write if we are a seq_cst read. */ - if (!curr->is_seqcst()|| (!act->is_seqcst() && (last_seq_cst==NULL||!act->happens_before(last_seq_cst))) || act == last_seq_cst) { + if (!curr->is_seqcst() || (!act->is_seqcst() && (last_seq_cst == NULL || !act->happens_before(last_seq_cst))) || act == last_seq_cst) { DEBUG("Adding action to may_read_from:\n"); if (DBG_ENABLED()) { act->print(); @@ -1462,7 +1595,7 @@ void ModelChecker::print_summary() #if SUPPORT_MOD_ORDER_DUMP scheduler->print(); char buffername[100]; - sprintf(buffername, "exec%u",num_executions); + sprintf(buffername, "exec%04u", num_executions); mo_graph->dumpGraphToFile(buffername); #endif @@ -1483,6 +1616,10 @@ void ModelChecker::add_thread(Thread *t) scheduler->add_thread(t); } +/** + * Removes a thread from the scheduler. + * @param the thread to remove. + */ void ModelChecker::remove_thread(Thread *t) { scheduler->remove_thread(t); @@ -1520,6 +1657,7 @@ bool ModelChecker::take_step() { priv->nextThread = check_current_action(priv->current_action); priv->current_action = NULL; + if (curr->is_blocked() || curr->is_complete()) scheduler->remove_thread(curr); } else {