X-Git-Url: http://plrg.eecs.uci.edu/git/?a=blobdiff_plain;ds=sidebyside;f=model.cc;h=cbd5617d8238f9326720fbcfb7dfb9c08864b6e3;hb=dab4897e809f77fa6d7574563a169f752dbef43d;hp=167ea947a79a020964ec13fc67d67077aae961f7;hpb=7417fdabc7a66c6c05aa87cafb5961aacebffa48;p=cdsspec-compiler.git diff --git a/model.cc b/model.cc index 167ea94..cbd5617 100644 --- a/model.cc +++ b/model.cc @@ -2,6 +2,7 @@ #include #include #include +#include #include "model.h" #include "action.h" @@ -83,7 +84,6 @@ 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()), condvar_waiters_map(new HashTable()), obj_thrd_map(new HashTable *, uintptr_t, 4 >()), promises(new SnapVector()), @@ -109,7 +109,6 @@ ModelChecker::~ModelChecker() delete obj_thrd_map; delete obj_map; - delete lock_waiters_map; delete condvar_waiters_map; delete action_trace; @@ -156,9 +155,6 @@ void ModelChecker::reset_to_initial_state() DEBUG("+++ Resetting to initial state +++\n"); node_stack->reset_execution(); - /* Print all model-checker output before rollback */ - fflush(model_out); - /** * FIXME: if we utilize partial rollback, we will need to free only * those pending actions which were NOT pending before the rollback @@ -260,20 +256,8 @@ Thread * ModelChecker::get_next_thread() scheduler->update_sleep_set(prevnode); /* Reached divergence point */ - if (nextnode->increment_misc()) { - /* The next node will try to satisfy a different misc_index values. */ - tid = next->get_tid(); - node_stack->pop_restofstack(2); - } else if (nextnode->increment_promise()) { - /* The next node will try to satisfy a different set of promises. */ - tid = next->get_tid(); - node_stack->pop_restofstack(2); - } else if (nextnode->increment_read_from()) { - /* The next node will read from a different value. */ - tid = next->get_tid(); - node_stack->pop_restofstack(2); - } else if (nextnode->increment_relseq_break()) { - /* The next node will try to resolve a release sequence differently */ + if (nextnode->increment_behaviors()) { + /* Execute the same thread with a new behavior */ tid = next->get_tid(); node_stack->pop_restofstack(2); } else { @@ -300,7 +284,7 @@ Thread * ModelChecker::get_next_thread() } DEBUG("*** ModelChecker chose next thread = %d ***\n", id_to_int(tid)); ASSERT(tid != THREAD_ID_T_NONE); - return thread_map->get(id_to_int(tid)); + return get_thread(id_to_int(tid)); } /** @@ -409,22 +393,6 @@ bool ModelChecker::is_deadlocked() const return blocking_threads; } -/** - * Check if a Thread has entered a circular wait deadlock situation. This will - * not check other threads for potential deadlock situations, and may miss - * deadlocks involving WAIT. - * - * @param t The thread which may have entered a deadlock - * @return True if this Thread entered a deadlock; false otherwise - */ -bool ModelChecker::is_circular_wait(const Thread *t) const -{ - for (Thread *waiting = t->waiting_on() ; waiting != NULL; waiting = waiting->waiting_on()) - if (waiting == t) - return true; - return false; -} - /** * Check if this is a complete execution. That is, have all thread completed * execution (rather than exiting because sleep sets have forced a redundant @@ -452,9 +420,16 @@ bool ModelChecker::is_complete_execution() const * @param msg Descriptive message for the bug (do not include newline char) * @return True if bug is immediately-feasible */ -bool ModelChecker::assert_bug(const char *msg) +bool ModelChecker::assert_bug(const char *msg, ...) { - priv->bugs.push_back(new bug_message(msg)); + char str[800]; + + va_list ap; + va_start(ap, msg); + vsnprintf(str, sizeof(str), msg, ap); + va_end(ap); + + priv->bugs.push_back(new bug_message(str)); if (isfeasibleprefix()) { set_assert(); @@ -785,6 +760,7 @@ void ModelChecker::set_backtracking(ModelAction *act) Node *node = prev->get_node()->get_parent(); + /* See Dynamic Partial Order Reduction (addendum), POPL '05 */ int low_tid, high_tid; if (node->enabled_status(t->get_id()) == THREAD_ENABLED) { low_tid = id_to_int(act->get_tid()); @@ -801,6 +777,7 @@ void ModelChecker::set_backtracking(ModelAction *act) if (i >= node->get_num_threads()) break; + /* See Dynamic Partial Order Reduction (addendum), POPL '05 */ /* Don't backtrack into a point where the thread is disabled or sleeping. */ if (node->enabled_status(tid) != THREAD_ENABLED) continue; @@ -996,32 +973,26 @@ bool ModelChecker::process_mutex(ModelAction *curr) } break; } + case ATOMIC_WAIT: case ATOMIC_UNLOCK: { - //unlock the lock - state->locked = NULL; - //wake up the other threads - action_list_t *waiters = get_safe_ptr_action(lock_waiters_map, curr->get_location()); - //activate all the waiting threads - for (action_list_t::iterator rit = waiters->begin(); rit != waiters->end(); rit++) { - scheduler->wake(get_thread(*rit)); + /* wake up the other threads */ + for (unsigned int i = 0; i < get_num_threads(); i++) { + Thread *t = get_thread(int_to_id(i)); + Thread *curr_thrd = get_thread(curr); + if (t->waiting_on() == curr_thrd && t->get_pending()->is_lock()) + scheduler->wake(t); } - waiters->clear(); - break; - } - case ATOMIC_WAIT: { - //unlock the lock + + /* unlock the lock - after checking who was waiting on it */ state->locked = NULL; - //wake up the other threads - action_list_t *waiters = get_safe_ptr_action(lock_waiters_map, (void *) curr->get_value()); - //activate all the waiting threads - for (action_list_t::iterator rit = waiters->begin(); rit != waiters->end(); rit++) { - scheduler->wake(get_thread(*rit)); - } - waiters->clear(); - //check whether we should go to sleep or not...simulate spurious failures + + if (!curr->is_wait()) + break; /* The rest is only for ATOMIC_WAIT */ + + /* Should we go to sleep? (simulate spurious failures) */ if (curr->get_node()->get_misc() == 0) { get_safe_ptr_action(condvar_waiters_map, curr->get_location())->push_back(curr); - //disable us + /* disable us */ scheduler->sleep(get_thread(curr)); } break; @@ -1056,7 +1027,7 @@ bool ModelChecker::process_mutex(ModelAction *curr) * * If one of the following is true: * (a) there are no pending promises - * (b) the reader is ordered after the latest Promise creation + * (b) the reader and writer do not cross any promises * Then, it is safe to pass a future value back now. * * Otherwise, we must save the pending future value until (a) or (b) is true @@ -1068,8 +1039,18 @@ bool ModelChecker::process_mutex(ModelAction *curr) bool ModelChecker::promises_may_allow(const ModelAction *writer, const ModelAction *reader) const { - return promises->empty() || - *(promises->back()->get_reader(0)) < *reader; + if (promises->empty()) + return true; + for(int i=promises->size()-1;i>=0;i--) { + ModelAction *pr=(*promises)[i]->get_reader(0); + //reader is after promise...doesn't cross any promise + if (*reader > *pr) + return true; + //writer is after promise, reader before...bad... + if (*writer > *pr) + return false; + } + return true; } /** @@ -1245,9 +1226,12 @@ bool ModelChecker::process_thread_action(ModelAction *curr) } case THREAD_FINISH: { Thread *th = get_thread(curr); - while (!th->wait_list_empty()) { - ModelAction *act = th->pop_wait_list(); - scheduler->wake(get_thread(act)); + /* Wake up any joining threads */ + for (unsigned int i = 0; i < get_num_threads(); i++) { + Thread *waiting = get_thread(int_to_id(i)); + if (waiting->waiting_on() == th && + waiting->get_pending()->is_thread_join()) + scheduler->wake(waiting); } th->complete(); /* Completed thread can't satisfy promises */ @@ -1483,17 +1467,13 @@ void ModelChecker::thread_blocking_check_promises(Thread *blocker, Thread *waiti */ bool ModelChecker::check_action_enabled(ModelAction *curr) { if (curr->is_lock()) { - std::mutex *lock = (std::mutex *)curr->get_location(); + std::mutex *lock = curr->get_mutex(); struct std::mutex_state *state = lock->get_state(); - if (state->locked) { - //Stick the action in the appropriate waiting queue - get_safe_ptr_action(lock_waiters_map, curr->get_location())->push_back(curr); + if (state->locked) return false; - } - } else if (curr->get_type() == THREAD_JOIN) { - Thread *blocking = (Thread *)curr->get_location(); + } else if (curr->is_thread_join()) { + Thread *blocking = curr->get_thread_operand(); if (!blocking->is_complete()) { - blocking->push_wait_list(curr); thread_blocking_check_promises(blocking, get_thread(curr)); return false; } @@ -1517,15 +1497,6 @@ ModelAction * ModelChecker::check_current_action(ModelAction *curr) { ASSERT(curr); bool second_part_of_rmw = curr->is_rmwc() || curr->is_rmw(); - - if (!check_action_enabled(curr)) { - /* Make the execution look like we chose to run this action - * much later, when a lock/join can succeed */ - get_thread(curr)->set_pending(curr); - scheduler->sleep(get_thread(curr)); - return NULL; - } - bool newly_explored = initialize_curr_action(&curr); DBG(); @@ -3105,32 +3076,14 @@ Thread * ModelChecker::take_step(ModelAction *curr) Thread *curr_thrd = get_thread(curr); ASSERT(curr_thrd->get_state() == THREAD_READY); + ASSERT(check_action_enabled(curr)); /* May have side effects? */ curr = check_current_action(curr); - - /* Infeasible -> don't take any more steps */ - if (is_infeasible()) - return NULL; - else if (isfeasibleprefix() && have_bug_reports()) { - set_assert(); - return NULL; - } - - if (params.bound != 0 && priv->used_sequence_numbers > params.bound) - return NULL; + ASSERT(curr); if (curr_thrd->is_blocked() || curr_thrd->is_complete()) scheduler->remove_thread(curr_thrd); - Thread *next_thrd = NULL; - if (curr) - next_thrd = action_select_next_thread(curr); - if (!next_thrd) - next_thrd = get_next_thread(); - - DEBUG("(%d, %d)\n", curr_thrd ? id_to_int(curr_thrd->get_id()) : -1, - next_thrd ? id_to_int(next_thrd->get_id()) : -1); - - return next_thrd; + return action_select_next_thread(curr); } /** Wrapper to run the user's main function, with appropriate arguments */ @@ -3139,6 +3092,21 @@ void user_main_wrapper(void *) user_main(model->params.argc, model->params.argv); } +bool ModelChecker::should_terminate_execution() +{ + /* Infeasible -> don't take any more steps */ + if (is_infeasible()) + return true; + else if (isfeasibleprefix() && have_bug_reports()) { + set_assert(); + return true; + } + + if (params.bound != 0 && priv->used_sequence_numbers > params.bound) + return true; + return false; +} + /** @brief Run ModelChecker for the user program */ void ModelChecker::run() { @@ -3159,21 +3127,35 @@ void ModelChecker::run() Thread *thr = get_thread(tid); if (!thr->is_model_thread() && !thr->is_complete() && !thr->get_pending()) { switch_from_master(thr); - if (is_circular_wait(thr)) + if (thr->is_waiting_on(thr)) assert_bug("Deadlock detected"); } } + /* Don't schedule threads which should be disabled */ + for (unsigned int i = 0; i < get_num_threads(); i++) { + Thread *th = get_thread(int_to_id(i)); + ModelAction *act = th->get_pending(); + if (act && is_enabled(th) && !check_action_enabled(act)) { + scheduler->sleep(th); + } + } + /* Catch assertions from prior take_step or from * between-ModelAction bugs (e.g., data races) */ if (has_asserted()) break; + if (!t) + t = get_next_thread(); + if (!t || t->is_model_thread()) + break; + /* Consume the next action for a Thread */ ModelAction *curr = t->get_pending(); t->set_pending(NULL); t = take_step(curr); - } while (t && !t->is_model_thread()); + } while (!should_terminate_execution()); /* * Launch end-of-execution release sequence fixups only when