X-Git-Url: http://plrg.eecs.uci.edu/git/?p=c11tester.git;a=blobdiff_plain;f=model.cc;h=e4757bc6f0d0b919417e60ed9018e0bcd0e86301;hp=7f1e49dc0ee0fbce09ecda84a3b044dfec311bbe;hb=f71cd7c31df98cfc814254da887de9a30c53b31e;hpb=942ca53513b4c50f3f73bc4b123c3552dbc71ca6 diff --git a/model.cc b/model.cc index 7f1e49dc..e4757bc6 100644 --- a/model.cc +++ b/model.cc @@ -11,6 +11,7 @@ #include "cyclegraph.h" #include "promise.h" #include "datarace.h" +#include "mutex.h" #define INITIAL_THREAD_ID 0 @@ -27,10 +28,11 @@ ModelChecker::ModelChecker(struct model_params params) : action_trace(new action_list_t()), thread_map(new HashTable()), obj_map(new HashTable()), + lock_waiters_map(new HashTable()), obj_thrd_map(new HashTable, uintptr_t, 4 >()), promises(new std::vector()), futurevalues(new std::vector()), - lazy_sync_with_release(new HashTable, uintptr_t, 4>()), + pending_acq_rel_seq(new std::vector()), thrd_last_action(new std::vector(1)), node_stack(new NodeStack()), mo_graph(new CycleGraph()), @@ -42,8 +44,6 @@ 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; - - lazy_sync_size = &priv->lazy_sync_size; } /** @brief Destructor */ @@ -55,13 +55,14 @@ ModelChecker::~ModelChecker() delete obj_thrd_map; delete obj_map; + delete lock_waiters_map; delete action_trace; for (unsigned int i = 0; i < promises->size(); i++) delete (*promises)[i]; delete promises; - delete lazy_sync_with_release; + delete pending_acq_rel_seq; delete thrd_last_action; delete node_stack; @@ -83,19 +84,19 @@ void ModelChecker::reset_to_initial_state() 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; @@ -118,12 +119,14 @@ Thread * ModelChecker::get_next_thread(ModelAction *curr) { thread_id_t tid; - /* Do not split atomic actions. */ - if (curr->is_rmwr()) - return thread_current(); - /* The THREAD_CREATE action points to the created Thread */ - else if (curr->get_type() == THREAD_CREATE) - return (Thread *)curr->get_location(); + if (curr!=NULL) { + /* Do not split atomic actions. */ + if (curr->is_rmwr()) + return thread_current(); + /* The THREAD_CREATE action points to the created Thread */ + else if (curr->get_type() == THREAD_CREATE) + return (Thread *)curr->get_location(); + } /* Have we completed exploring the preselected path? */ if (diverge == NULL) @@ -195,58 +198,96 @@ bool ModelChecker::next_execution() ModelAction * ModelChecker::get_last_conflict(ModelAction *act) { - action_type type = act->get_type(); - - switch (type) { - case ATOMIC_READ: - case ATOMIC_WRITE: - case ATOMIC_RMW: - break; - default: - return NULL; + 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; + for (rit = list->rbegin(); rit != list->rend(); rit++) { + ModelAction *prev = *rit; + if (act->is_synchronizing(prev)) + return prev; + } + break; } - /* 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->is_synchronizing(prev)) - return prev; + 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 (act->is_conflicting_lock(prev)) + return prev; + } + 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 (!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(); + + 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(); + } - while (!node->is_enabled(t)) - t = t->get_parent(); + for(int i = low_tid; i < high_tid; i++) { + thread_id_t tid = int_to_id(i); + if (!node->is_enabled(tid)) + continue; - /* Check if this has been explored already */ - if (node->has_been_explored(t->get_id())) - return; + /* Check if this has been explored already */ + if (node->has_been_explored(tid)) + continue; - /* Cache the latest backtracking point */ - if (!priv->next_backtrack || *prev > *priv->next_backtrack) - priv->next_backtrack = prev; + /* 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(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(); + /* 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(); + } } } @@ -308,6 +349,63 @@ bool ModelChecker::process_read(ModelAction *curr, bool second_part_of_rmw) } } +/** + * 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. + */ +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()) { + case ATOMIC_TRYLOCK: { + bool success = !state->islocked; + curr->set_try_lock(success); + if (!success) { + get_thread(curr)->set_return_value(0); + break; + } + get_thread(curr)->set_return_value(1); + } + //otherwise fall into the lock case + case ATOMIC_LOCK: { + 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); + //synchronize with the previous unlock statement + if (unlock != NULL) + curr->synchronize_with(unlock); + break; + } + case ATOMIC_UNLOCK: { + //unlock the lock + state->islocked = false; + //wake up the other threads + 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++) { + scheduler->add_thread(get_thread((*rit)->get_tid())); + } + waiters->clear(); + break; + } + default: + ASSERT(0); + } +} + /** * Process a write ModelAction * @param curr The ModelAction to process @@ -319,7 +417,7 @@ 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)) @@ -333,6 +431,78 @@ bool ModelChecker::process_write(ModelAction *curr) return updated_mod_order || updated_promises; } +/** + * Initialize the current action by performing one or more of the following + * actions, as appropriate: merging RMWR and RMWC/RMW actions, stepping forward + * in the NodeStack, manipulating backtracking sets, allocating and + * 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. + */ +ModelAction * ModelChecker::initialize_curr_action(ModelAction *curr) +{ + ModelAction *newcurr; + + if (curr->is_rmwc() || curr->is_rmw()) { + newcurr = process_rmw(curr); + delete curr; + compute_promises(newcurr); + return newcurr; + } + + 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); + + 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())); + } else { + newcurr = curr; + /* + * Perform one-time actions when pushing new ModelAction onto + * NodeStack + */ + curr->create_cv(get_parent_action(curr->get_tid())); + if (curr->is_write()) + compute_promises(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(); + struct std::mutex_state * state = lock->get_state(); + if (state->islocked) { + //Stick the action in the appropriate waiting queue + lock_waiters_map->get_safe_ptr(curr->get_location())->push_back(curr); + return false; + } + } + + return true; +} + /** * This is the heart of the model checker routine. It performs model-checking * actions corresponding to a given "current action." Among other processes, it @@ -347,44 +517,29 @@ bool ModelChecker::process_write(ModelAction *curr) */ Thread * ModelChecker::check_current_action(ModelAction *curr) { - bool second_part_of_rmw = false; - ASSERT(curr); - if (curr->is_rmwc() || curr->is_rmw()) { - ModelAction *tmp = process_rmw(curr); - second_part_of_rmw = true; - delete curr; - curr = tmp; - compute_promises(curr); - } else { - ModelAction *tmp = node_stack->explore_action(curr); - if (tmp) { - /* Discard duplicate ModelAction; use action from NodeStack */ - /* First restore type and order in case of RMW operation */ - if (curr->is_rmwr()) - tmp->copy_typeandorder(curr); - - /* If we have diverged, we need to reset the clock vector. */ - if (diverge == NULL) - tmp->create_cv(get_parent_action(tmp->get_tid())); - - delete curr; - curr = tmp; - } else { - /* - * Perform one-time actions when pushing new ModelAction onto - * NodeStack - */ - curr->create_cv(get_parent_action(curr->get_tid())); - /* Build may_read_from set */ - if (curr->is_read()) - build_reads_from_past(curr); - if (curr->is_write()) - compute_promises(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 + get_current_thread()->set_pending(curr); + remove_thread(get_current_thread()); + return get_next_thread(NULL); } + ModelAction *newcurr = initialize_curr_action(curr); + + /* 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: { @@ -399,6 +554,8 @@ Thread * ModelChecker::check_current_action(ModelAction *curr) if (!blocking->is_complete()) { blocking->push_wait_list(curr); scheduler->sleep(waiting); + } else { + do_complete_join(curr); } break; } @@ -408,6 +565,7 @@ Thread * ModelChecker::check_current_action(ModelAction *curr) ModelAction *act = th->pop_wait_list(); Thread *wake = get_thread(act); scheduler->wake(wake); + do_complete_join(act); } th->complete(); break; @@ -420,10 +578,6 @@ Thread * ModelChecker::check_current_action(ModelAction *curr) break; } - /* Add current action to lists before work_queue loop */ - if (!second_part_of_rmw) - add_action_to_lists(curr); - work_queue_t work_queue(1, CheckCurrWorkEntry(curr)); while (!work_queue.empty()) { @@ -440,6 +594,9 @@ Thread * ModelChecker::check_current_action(ModelAction *curr) if (act->is_write() && process_write(act)) updated = true; + if (act->is_mutex_op()) + process_mutex(act); + if (updated) work_queue.push_back(CheckRelSeqWorkEntry(act->get_location())); break; @@ -478,6 +635,19 @@ Thread * ModelChecker::check_current_action(ModelAction *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(); @@ -502,18 +672,18 @@ 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() { 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()) { @@ -645,7 +815,7 @@ 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: @@ -704,7 +874,7 @@ 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 @@ -840,7 +1010,7 @@ 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); } @@ -864,7 +1034,7 @@ 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)) @@ -895,8 +1065,7 @@ bool ModelChecker::thin_air_constraint_may_allow(const ModelAction * writer, con * @return true, if the ModelChecker is certain that release_heads is complete; * false otherwise */ -bool ModelChecker::release_seq_head(const ModelAction *rf, - std::vector< const ModelAction *, MyAlloc > *release_heads) const +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 */ @@ -952,10 +1121,12 @@ bool ModelChecker::release_seq_head(const ModelAction *rf, * the release seq? */ bool future_ordered = false; + ModelAction *last = get_last_action(int_to_id(i)); + if (last && rf->happens_before(last)) + 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; @@ -964,6 +1135,10 @@ bool ModelChecker::release_seq_head(const ModelAction *rf, continue; } + /* Only writes can break release sequences */ + if (!act->is_write()) + continue; + /* Check modification order */ if (mo_graph->checkReachable(rf, act)) { /* rf --mo--> act */ @@ -1001,18 +1176,14 @@ bool ModelChecker::release_seq_head(const ModelAction *rf, * with the head(s) of the release sequence(s), if they exists with certainty. * @see ModelChecker::release_seq_head */ -void ModelChecker::get_release_seq_heads(ModelAction *act, - std::vector< const ModelAction *, MyAlloc > *release_heads) +void ModelChecker::get_release_seq_heads(ModelAction *act, rel_heads_list_t *release_heads) { const ModelAction *rf = act->get_reads_from(); bool complete; complete = release_seq_head(rf, release_heads); if (!complete) { /* add act to 'lazy checking' list */ - std::list *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); } } @@ -1023,7 +1194,7 @@ void ModelChecker::get_release_seq_heads(ModelAction *act, * 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 @@ -1031,17 +1202,19 @@ void ModelChecker::get_release_seq_heads(ModelAction *act, */ bool ModelChecker::resolve_release_sequences(void *location, work_queue_t *work_queue) { - std::list *list; - list = lazy_sync_with_release->getptr(location); - if (!list) - return false; - bool updated = false; - std::list::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(); - std::vector< const ModelAction *, MyAlloc > release_heads; + 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++) { @@ -1057,7 +1230,7 @@ bool ModelChecker::resolve_release_sequences(void *location, work_queue_t *work_ /* propagate synchronization to later actions */ action_list_t::reverse_iterator it = action_trace->rbegin(); - while ((*it) != act) { + for (; (*it) != act; it++) { ModelAction *propagate = *it; if (act->happens_before(propagate)) { propagate->synchronize_with(act); @@ -1066,10 +1239,9 @@ 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++; } @@ -1105,12 +1277,18 @@ 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 nthreads = get_num_threads(); - if ((int)thrd_last_action->size() < nthreads) - thrd_last_action->resize(nthreads); - return (*thrd_last_action)[id_to_int(tid)]; + int threadid = id_to_int(tid); + if (threadid < (int)thrd_last_action->size()) + return (*thrd_last_action)[id_to_int(tid)]; + else + return NULL; } /** @@ -1121,7 +1299,7 @@ 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); @@ -1133,6 +1311,26 @@ ModelAction * ModelChecker::get_last_seq_cst(ModelAction *curr) return NULL; } +/** + * 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) | 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()) + return *rit; + return NULL; +} + ModelAction * ModelChecker::get_parent_action(thread_id_t tid) { ModelAction *parent = get_last_action(tid); @@ -1258,11 +1456,11 @@ void ModelChecker::build_reads_from_past(ModelAction *curr) ModelAction *act = *rit; /* Only consider 'write' actions */ - if (!act->is_write()) + if (!act->is_write() || act == 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(); @@ -1318,7 +1516,7 @@ 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 @@ -1339,6 +1537,11 @@ 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); @@ -1366,25 +1569,23 @@ int ModelChecker::switch_to_master(ModelAction *act) * @return Returns true (success) if a step was taken and false otherwise. */ bool ModelChecker::take_step() { - Thread *curr, *next; - if (has_asserted()) return false; - curr = thread_current(); + Thread * curr = thread_current(); if (curr) { if (curr->get_state() == THREAD_READY) { ASSERT(priv->current_action); priv->nextThread = check_current_action(priv->current_action); priv->current_action = NULL; - if (!curr->is_blocked() && !curr->is_complete()) - scheduler->add_thread(curr); + if (curr->is_blocked() || curr->is_complete()) + scheduler->remove_thread(curr); } else { ASSERT(false); } } - next = scheduler->next_thread(priv->nextThread); + Thread * next = scheduler->next_thread(priv->nextThread); /* Infeasible -> don't take any more steps */ if (!isfeasible()) @@ -1397,6 +1598,15 @@ bool ModelChecker::take_step() { /* next == NULL -> don't take any more steps */ if (!next) return false; + + if ( next->get_pending() != NULL ) { + //restart a pending action + set_current_action(next->get_pending()); + next->set_pending(NULL); + next->set_state(THREAD_READY); + return true; + } + /* Return false only if swap fails with an error */ return (Thread::swap(&system_context, next) == 0); }