X-Git-Url: http://plrg.eecs.uci.edu/git/?p=c11tester.git;a=blobdiff_plain;f=model.cc;h=8b7201f1b88c4edf98475e0ebeadc7ecd6fd6f32;hp=66ca8be3fdc89fa5014d8787819a657576cf138b;hb=bbc3405aa23e6eafb3863738c4e203764694e9a4;hpb=c9e8710d3fc3e6915676c088511c9ff37c023de7 diff --git a/model.cc b/model.cc index 66ca8be3..8b7201f1 100644 --- a/model.cc +++ b/model.cc @@ -12,6 +12,7 @@ #include "promise.h" #include "datarace.h" #include "mutex.h" +#include "threads.h" #define INITIAL_THREAD_ID 0 @@ -25,6 +26,7 @@ ModelChecker::ModelChecker(struct model_params params) : num_executions(0), num_feasible_executions(0), diverge(NULL), + earliest_diverge(NULL), action_trace(new action_list_t()), thread_map(new HashTable()), obj_map(new HashTable()), @@ -38,7 +40,8 @@ ModelChecker::ModelChecker(struct model_params params) : 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)); @@ -80,6 +83,7 @@ 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); } @@ -96,6 +100,12 @@ int ModelChecker::get_num_threads() return priv->next_thread_id; } +/** @return The currently executing Thread. */ +Thread * ModelChecker::get_current_thread() +{ + return scheduler->get_current_thread(); +} + /** @return a sequence number for a new ModelAction */ modelclock_t ModelChecker::get_next_seq_num() { @@ -136,6 +146,9 @@ Thread * ModelChecker::get_next_thread(ModelAction *curr) ModelAction *next = node_stack->get_next()->get_action(); if (next == diverge) { + if (earliest_diverge == NULL || *diverge < *earliest_diverge) + earliest_diverge=diverge; + Node *nextnode = next->get_node(); /* Reached divergence point */ if (nextnode->increment_promise()) { @@ -155,8 +168,12 @@ Thread * ModelChecker::get_next_thread(ModelAction *curr) Node *node = nextnode->get_parent(); tid = node->get_next_backtrack(); node_stack->pop_restofstack(1); + if (diverge==earliest_diverge) { + earliest_diverge=node->get_action(); + } } DEBUG("*** Divergence point ***\n"); + diverge = NULL; } else { tid = next->get_tid(); @@ -178,8 +195,20 @@ bool ModelChecker::next_execution() DBG(); num_executions++; - if (isfinalfeasible()) + + if (isfinalfeasible()) { + printf("Earliest divergence point since last feasible execution:\n"); + if (earliest_diverge) + earliest_diverge->print(false); + else + printf("(Not set)\n"); + + earliest_diverge = NULL; num_feasible_executions++; + } + + DEBUG("Number of acquires waiting on pending release sequences: %lu\n", + pending_acq_rel_seq->size()); if (isfinalfeasible() || DBG_ENABLED()) print_summary(); @@ -334,7 +363,7 @@ 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); } @@ -374,8 +403,10 @@ bool ModelChecker::process_read(ModelAction *curr, bool second_part_of_rmw) * * 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 */ -void ModelChecker::process_mutex(ModelAction *curr) { +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()) { @@ -397,8 +428,10 @@ void ModelChecker::process_mutex(ModelAction *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: { @@ -408,7 +441,7 @@ void ModelChecker::process_mutex(ModelAction *curr) { 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())); + scheduler->wake(get_thread(*rit)); } waiters->clear(); break; @@ -416,6 +449,7 @@ void ModelChecker::process_mutex(ModelAction *curr) { default: ASSERT(0); } + return false; } /** @@ -452,11 +486,11 @@ bool ModelChecker::process_write(ModelAction *curr) * (e.g., ATOMIC_{READ,WRITE,RMW,LOCK}, etc.) * * @param curr The current action - * @return True if synchronization was updated + * @return True if synchronization was updated or a thread completed */ bool ModelChecker::process_thread_action(ModelAction *curr) { - bool synchronized = false; + bool updated = false; switch (curr->get_type()) { case THREAD_CREATE: { @@ -473,7 +507,7 @@ bool ModelChecker::process_thread_action(ModelAction *curr) scheduler->sleep(waiting); } else { do_complete_join(curr); - synchronized = true; + updated = true; /* trigger rel-seq checks */ } break; } @@ -484,9 +518,10 @@ bool ModelChecker::process_thread_action(ModelAction *curr) Thread *wake = get_thread(act); scheduler->wake(wake); do_complete_join(act); - synchronized = true; + updated = true; /* trigger rel-seq checks */ } th->complete(); + updated = true; /* trigger rel-seq checks */ break; } case THREAD_START: { @@ -497,7 +532,7 @@ bool ModelChecker::process_thread_action(ModelAction *curr) break; } - return synchronized; + return updated; } /** @@ -518,10 +553,14 @@ 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; } + curr->set_seq_number(get_next_seq_num()); + newcurr = node_stack->explore_action(curr, scheduler->get_enabled()); if (newcurr) { /* First restore type and order in case of RMW operation */ @@ -534,18 +573,19 @@ ModelAction * ModelChecker::initialize_curr_action(ModelAction *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())); + /* Always compute new clock vector */ + newcurr->create_cv(get_parent_action(newcurr->get_tid())); } else { newcurr = curr; + + /* Always compute new clock vector */ + newcurr->create_cv(get_parent_action(newcurr->get_tid())); /* * 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); + if (newcurr->is_write()) + compute_promises(newcurr); } return newcurr; } @@ -593,7 +633,7 @@ Thread * ModelChecker::check_current_action(ModelAction *curr) /* 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()); + scheduler->sleep(get_current_thread()); return get_next_thread(NULL); } @@ -608,6 +648,7 @@ Thread * ModelChecker::check_current_action(ModelAction *curr) build_reads_from_past(curr); curr = newcurr; + /* Initialize work_queue with the "current action" work */ work_queue_t work_queue(1, CheckCurrWorkEntry(curr)); while (!work_queue.empty()) { @@ -617,20 +658,24 @@ 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 */ - process_thread_action(curr); + 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; } @@ -643,13 +688,15 @@ Thread * ModelChecker::check_current_action(ModelAction *curr) bool updated = false; if (act->is_read()) { - if (r_modification_order(act, act->get_reads_from())) + const ModelAction *rf = act->get_reads_from(); + if (rf != NULL && r_modification_order(act, rf)) updated = true; } if (act->is_write()) { if (w_modification_order(act)) updated = true; } + mo_graph->commitChanges(); if (updated) work_queue.push_back(CheckRelSeqWorkEntry(act->get_location())); @@ -713,6 +760,9 @@ bool ModelChecker::isfeasibleprefix() { /** @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(); } @@ -726,10 +776,12 @@ 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. */ @@ -763,23 +815,21 @@ 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(); @@ -798,17 +848,18 @@ 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*/ @@ -890,7 +941,11 @@ bool ModelChecker::r_modification_order(ModelAction *curr, const ModelAction *rf } } else { const ModelAction *prevreadfrom = act->get_reads_from(); - if (prevreadfrom != NULL && rf != prevreadfrom) { + //if the previous read is unresolved, keep going... + if (prevreadfrom == NULL) + continue; + + if (rf != prevreadfrom) { mo_graph->addEdge(prevreadfrom, rf); added = true; } @@ -931,10 +986,10 @@ 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; @@ -942,12 +997,25 @@ 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; } @@ -1002,14 +1070,22 @@ bool ModelChecker::w_modification_order(ModelAction *curr) ModelAction *act = *rit; if (act == curr) { /* - * If RMW, we already have all relevant edges, - * so just skip to next thread. - * If normal write, we need to look at earlier - * actions, so continue processing list. + * 1) If RMW and it actually read from something, then we + * already have all relevant edges, so just skip to next + * thread. + * + * 2) If RMW and it didn't read from anything, we should + * whatever edge we can get to speed up convergence. + * + * 3) If normal write, we need to look at earlier actions, so + * continue processing list. */ - if (curr->is_rmw()) - break; - else + if (curr->is_rmw()) { + if (curr->get_reads_from()!=NULL) + break; + else + continue; + } else continue; } @@ -1026,8 +1102,12 @@ bool ModelChecker::w_modification_order(ModelAction *curr) */ if (act->is_write()) mo_graph->addEdge(act, curr); - else if (act->is_read() && act->get_reads_from() != NULL) + else if (act->is_read()) { + //if previous read accessed a null, just keep going + if (act->get_reads_from() == NULL) + continue; mo_graph->addEdge(act->get_reads_from(), curr); + } added = true; break; } else if (act->is_read() && !act->is_synchronizing(curr) && @@ -1098,6 +1178,10 @@ 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 { + /* Only check for release sequences if there are no cycles */ + if (mo_graph->checkForCycles()) + return false; + while (rf) { ASSERT(rf->is_write()); @@ -1161,7 +1245,8 @@ bool ModelChecker::release_seq_head(const ModelAction *rf, rel_heads_list_t *rel bool future_ordered = false; ModelAction *last = get_last_action(int_to_id(i)); - if (last && rf->happens_before(last)) + if (last && (rf->happens_before(last) || + last->get_type() == THREAD_FINISH)) future_ordered = true; for (rit = list->rbegin(); rit != list->rend(); rit++) { @@ -1258,19 +1343,23 @@ bool ModelChecker::resolve_release_sequences(void *location, work_queue_t *work_ 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(); } } if (updated) { + /* Re-check all pending release sequences */ + work_queue->push_back(CheckRelSeqWorkEntry(NULL)); /* Re-check act for mo_graph edges */ work_queue->push_back(MOEdgeWorkEntry(act)); /* propagate synchronization to later actions */ - action_list_t::reverse_iterator it = action_trace->rbegin(); - for (; (*it) != act; it++) { - 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 */ @@ -1402,16 +1491,20 @@ 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()); + + delete(promise); promises->erase(promises->begin() + promise_index); resolved = true; } else @@ -1545,6 +1638,34 @@ static void print_list(action_list_t *list) printf("---------------------------------------------------------------------\n"); } +#if SUPPORT_MOD_ORDER_DUMP +void ModelChecker::dumpGraph(char *filename) { + char buffer[200]; + sprintf(buffer, "%s.dot",filename); + FILE *file=fopen(buffer, "w"); + fprintf(file, "digraph %s {\n",filename); + mo_graph->dumpNodes(file); + ModelAction ** thread_array=(ModelAction **)model_calloc(1, sizeof(ModelAction *)*get_num_threads()); + + for (action_list_t::iterator it = action_trace->begin(); it != action_trace->end(); it++) { + ModelAction *action=*it; + if (action->is_read()) { + fprintf(file, "N%u [label=\"%u, T%u\"];\n", action->get_seq_number(),action->get_seq_number(), action->get_tid()); + if (action->get_reads_from()!=NULL) + fprintf(file, "N%u -> N%u[label=\"rf\", color=red];\n", action->get_seq_number(), action->get_reads_from()->get_seq_number()); + } + if (thread_array[action->get_tid()] != NULL) { + fprintf(file, "N%u -> N%u[label=\"sb\", color=blue];\n", thread_array[action->get_tid()]->get_seq_number(), action->get_seq_number()); + } + + thread_array[action->get_tid()]=action; + } + fprintf(file,"}\n"); + model_free(thread_array); + fclose(file); +} +#endif + void ModelChecker::print_summary() { printf("\n"); @@ -1557,6 +1678,8 @@ void ModelChecker::print_summary() char buffername[100]; sprintf(buffername, "exec%04u", num_executions); mo_graph->dumpGraphToFile(buffername); + sprintf(buffername, "graph%04u", num_executions); + dumpGraph(buffername); #endif if (!isfinalfeasible()) @@ -1585,12 +1708,35 @@ void ModelChecker::remove_thread(Thread *t) scheduler->remove_thread(t); } +/** + * @brief Get a Thread reference by its ID + * @param tid The Thread's ID + * @return A Thread reference + */ +Thread * ModelChecker::get_thread(thread_id_t tid) +{ + return thread_map->get(id_to_int(tid)); +} + +/** + * @brief Get a reference to the Thread in which a ModelAction was executed + * @param act The ModelAction + * @return A Thread reference + */ +Thread * ModelChecker::get_thread(ModelAction *act) +{ + return get_thread(act->get_tid()); +} + /** * Switch from a user-context to the "master thread" context (a.k.a. system * context). This switch is made with the intention of exploring a particular * model-checking action (described by a ModelAction object). Must be called * from a user-thread context. - * @param act The current action that will be explored. Must not be NULL. + * + * @param act The current action that will be explored. May be NULL only if + * trace is exiting via an assertion (see ModelChecker::set_assert and + * ModelChecker::has_asserted). * @return Return status from the 'swap' call (i.e., success/fail, 0/-1) */ int ModelChecker::switch_to_master(ModelAction *act) @@ -1610,35 +1756,36 @@ bool ModelChecker::take_step() { if (has_asserted()) return false; - Thread * 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->remove_thread(curr); } else { ASSERT(false); } } - Thread * next = scheduler->next_thread(priv->nextThread); + Thread *next = scheduler->next_thread(priv->nextThread); /* Infeasible -> don't take any more steps */ if (!isfeasible()) return false; - if (next) - next->set_state(THREAD_RUNNING); DEBUG("(%d, %d)\n", curr ? curr->get_id() : -1, next ? next->get_id() : -1); /* next == NULL -> don't take any more steps */ if (!next) return false; - if ( next->get_pending() != NULL ) { - //restart a pending action + next->set_state(THREAD_RUNNING); + + if (next->get_pending() != NULL) { + /* restart a pending action */ set_current_action(next->get_pending()); next->set_pending(NULL); next->set_state(THREAD_READY);