X-Git-Url: http://plrg.eecs.uci.edu/git/?p=c11tester.git;a=blobdiff_plain;f=model.cc;h=508f3b98284920860c9ce5eb4231b786b070b979;hp=a13ccb7d0b7114aaa1a20adbeca5d1eb6927dbc9;hb=05f82cd6ab941db2d63ca83e778a430752de1900;hpb=31246eff241f4593a33501f8c33b6eadca1d7664 diff --git a/model.cc b/model.cc index a13ccb7d..508f3b98 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>()), + lazy_sync_with_release(new HashTable()), thrd_last_action(new std::vector(1)), node_stack(new NodeStack()), mo_graph(new CycleGraph()), @@ -55,6 +57,7 @@ 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++) @@ -83,19 +86,19 @@ 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 +121,14 @@ 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 +200,89 @@ 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; } 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(); - - while (!node->is_enabled(t)) - t = t->get_parent(); + Node * node = prev->get_node()->get_parent(); - /* Check if this has been explored already */ - if (node->has_been_explored(t->get_id())) - return; - - /* Cache the latest backtracking point */ - if (!priv->next_backtrack || *prev > *priv->next_backtrack) - priv->next_backtrack = prev; + 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(); + } + + for(int i=low_tid;iis_enabled(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(); + /* 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; + + /* 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 +344,65 @@ 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 @@ -333,6 +428,17 @@ 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; @@ -344,12 +450,15 @@ ModelAction * ModelChecker::initialize_curr_action(ModelAction *curr) return newcurr; } - newcurr = node_stack->explore_action(curr); + 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; @@ -369,6 +478,28 @@ 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(); + 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 @@ -387,8 +518,20 @@ 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 + 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); @@ -408,6 +551,8 @@ 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; } @@ -417,6 +562,7 @@ 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; @@ -429,10 +575,6 @@ 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()) { @@ -449,6 +591,9 @@ 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; @@ -487,6 +632,19 @@ 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(); @@ -511,18 +669,18 @@ 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; } -/** @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()) { @@ -904,8 +1062,7 @@ 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 */ @@ -961,10 +1118,12 @@ 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; @@ -973,6 +1132,10 @@ 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 */ @@ -1010,15 +1173,14 @@ 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; + action_list_t *list; list = lazy_sync_with_release->get_safe_ptr(act->get_location()); list->push_back(act); (*lazy_sync_size)++; @@ -1040,17 +1202,17 @@ void ModelChecker::get_release_seq_heads(ModelAction *act, */ bool ModelChecker::resolve_release_sequences(void *location, work_queue_t *work_queue) { - std::list *list; + action_list_t *list; list = lazy_sync_with_release->getptr(location); if (!list) return false; bool updated = false; - std::list::iterator it = list->begin(); + action_list_t::iterator it = list->begin(); while (it != list->end()) { ModelAction *act = *it; 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++) { @@ -1114,12 +1276,18 @@ 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; } /** @@ -1130,7 +1298,7 @@ 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); @@ -1142,6 +1310,26 @@ 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); @@ -1327,7 +1515,7 @@ 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 @@ -1375,25 +1563,23 @@ 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()) @@ -1406,6 +1592,15 @@ 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); }