X-Git-Url: http://plrg.eecs.uci.edu/git/?p=c11tester.git;a=blobdiff_plain;f=model.cc;h=508f3b98284920860c9ce5eb4231b786b070b979;hp=ec99b9a745de0960087e1f4a4bd33aafa82a920c;hb=05f82cd6ab941db2d63ca83e778a430752de1900;hpb=bd893aac350f125dc990f0ccd32b8e3cf133e2fb diff --git a/model.cc b/model.cc index ec99b9a7..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 @@ -27,6 +28,7 @@ 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()), @@ -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 @@ -355,12 +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; @@ -380,6 +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 @@ -398,6 +518,14 @@ 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 */ @@ -463,6 +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; @@ -538,18 +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()) { @@ -987,10 +1118,12 @@ 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)) + 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; @@ -999,6 +1132,10 @@ 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 */ @@ -1139,12 +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; } /** @@ -1155,7 +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); @@ -1167,6 +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); @@ -1352,7 +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 @@ -1400,25 +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()) @@ -1431,6 +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); }