X-Git-Url: http://plrg.eecs.uci.edu/git/?p=cdsspec-compiler.git;a=blobdiff_plain;f=execution.cc;h=4496b9c63deeca6fa8198ec086425ba8fa1d6932;hp=17ea954a65570160ffccd1a42f247c95956b8fa2;hb=741d3d1160343d8545a783a2d05d3d0562b1c737;hpb=b5d7d602016a4640c31b79ba9598dceefa778ab6 diff --git a/execution.cc b/execution.cc index 17ea954..4496b9c 100644 --- a/execution.cc +++ b/execution.cc @@ -58,15 +58,15 @@ struct model_snapshot_members { /** @brief Constructor */ ModelExecution::ModelExecution(ModelChecker *m, - struct model_params *params, + const struct model_params *params, Scheduler *scheduler, NodeStack *node_stack) : model(m), params(params), scheduler(scheduler), action_trace(), - thread_map(), - obj_map(new HashTable()), + thread_map(2), /* We'll always need at least 2 threads */ + obj_map(), condvar_waiters_map(), obj_thrd_map(), promises(), @@ -80,17 +80,16 @@ ModelExecution::ModelExecution(ModelChecker *m, { /* Initialize a model-checker thread, for special ModelActions */ model_thread = new Thread(get_next_id()); - thread_map.put(id_to_int(model_thread->get_id()), model_thread); + add_thread(model_thread); scheduler->register_engine(this); + node_stack->register_engine(this); } /** @brief Destructor */ ModelExecution::~ModelExecution() { for (unsigned int i = 0; i < get_num_threads(); i++) - delete thread_map.get(i); - - delete obj_map; + delete get_thread(int_to_id(i)); for (unsigned int i = 0; i < promises.size(); i++) delete promises[i]; @@ -265,6 +264,28 @@ bool ModelExecution::is_deadlocked() const return blocking_threads; } +/** + * @brief Check if we are yield-blocked + * + * A program can be "yield-blocked" if all threads are ready to execute a + * yield. + * + * @return True if the program is yield-blocked; false otherwise + */ +bool ModelExecution::is_yieldblocked() const +{ + if (!params->yieldblock) + return false; + + for (unsigned int i = 0; i < get_num_threads(); i++) { + thread_id_t tid = int_to_id(i); + Thread *t = get_thread(tid); + if (t->get_pending() && t->get_pending()->is_yield()) + 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 @@ -274,6 +295,8 @@ bool ModelExecution::is_deadlocked() const */ bool ModelExecution::is_complete_execution() const { + if (is_yieldblocked()) + return false; for (unsigned int i = 0; i < get_num_threads(); i++) if (is_enabled(int_to_id(i))) return false; @@ -367,17 +390,22 @@ ModelAction * ModelExecution::get_last_fence_conflict(ModelAction *act) const ModelAction * ModelExecution::get_last_conflict(ModelAction *act) const { switch (act->get_type()) { - /* case ATOMIC_FENCE: fences don't directly cause backtracking */ + case ATOMIC_FENCE: + /* Only seq-cst fences can (directly) cause backtracking */ + if (!act->is_seqcst()) + break; case ATOMIC_READ: case ATOMIC_WRITE: case ATOMIC_RMW: { ModelAction *ret = NULL; /* linear search: from most recent to oldest */ - action_list_t *list = get_safe_ptr_action(obj_map, act->get_location()); + action_list_t *list = obj_map.get(act->get_location()); action_list_t::reverse_iterator rit; for (rit = list->rbegin(); rit != list->rend(); rit++) { ModelAction *prev = *rit; + if (prev == act) + continue; if (prev->could_synchronize_with(act)) { ret = prev; break; @@ -396,7 +424,7 @@ ModelAction * ModelExecution::get_last_conflict(ModelAction *act) const case ATOMIC_LOCK: case ATOMIC_TRYLOCK: { /* linear search: from most recent to oldest */ - action_list_t *list = get_safe_ptr_action(obj_map, act->get_location()); + action_list_t *list = obj_map.get(act->get_location()); action_list_t::reverse_iterator rit; for (rit = list->rbegin(); rit != list->rend(); rit++) { ModelAction *prev = *rit; @@ -407,7 +435,7 @@ ModelAction * ModelExecution::get_last_conflict(ModelAction *act) const } case ATOMIC_UNLOCK: { /* linear search: from most recent to oldest */ - action_list_t *list = get_safe_ptr_action(obj_map, act->get_location()); + action_list_t *list = obj_map.get(act->get_location()); action_list_t::reverse_iterator rit; for (rit = list->rbegin(); rit != list->rend(); rit++) { ModelAction *prev = *rit; @@ -418,7 +446,7 @@ ModelAction * ModelExecution::get_last_conflict(ModelAction *act) const } case ATOMIC_WAIT: { /* linear search: from most recent to oldest */ - action_list_t *list = get_safe_ptr_action(obj_map, act->get_location()); + action_list_t *list = obj_map.get(act->get_location()); action_list_t::reverse_iterator rit; for (rit = list->rbegin(); rit != list->rend(); rit++) { ModelAction *prev = *rit; @@ -433,7 +461,7 @@ ModelAction * ModelExecution::get_last_conflict(ModelAction *act) const case ATOMIC_NOTIFY_ALL: case ATOMIC_NOTIFY_ONE: { /* linear search: from most recent to oldest */ - action_list_t *list = get_safe_ptr_action(obj_map, act->get_location()); + action_list_t *list = obj_map.get(act->get_location()); action_list_t::reverse_iterator rit; for (rit = list->rbegin(); rit != list->rend(); rit++) { ModelAction *prev = *rit; @@ -789,9 +817,10 @@ void ModelExecution::add_future_value(const ModelAction *writer, ModelAction *re /** * Process a write ModelAction * @param curr The ModelAction to process + * @param work The work queue, for adding fixup work * @return True if the mo_graph was updated or promises were resolved */ -bool ModelExecution::process_write(ModelAction *curr) +bool ModelExecution::process_write(ModelAction *curr, work_queue_t *work) { /* Readers to which we may send our future value */ ModelVector send_fv; @@ -804,7 +833,7 @@ bool ModelExecution::process_write(ModelAction *curr) if (promise) { earliest_promise_reader = promise->get_reader(0); - updated_promises = resolve_promise(curr, promise); + updated_promises = resolve_promise(curr, promise, work); } else earliest_promise_reader = NULL; @@ -997,21 +1026,9 @@ void ModelExecution::process_relseq_fixup(ModelAction *curr, work_queue_t *work_ /* Must synchronize */ if (!synchronize(release, acquire)) return; - /* Re-check all pending release sequences */ - work_queue->push_back(CheckRelSeqWorkEntry(NULL)); - /* Re-check act for mo_graph edges */ - work_queue->push_back(MOEdgeWorkEntry(acquire)); - - /* propagate synchronization to later actions */ - action_list_t::reverse_iterator rit = action_trace.rbegin(); - for (; (*rit) != acquire; rit++) { - ModelAction *propagate = *rit; - if (acquire->happens_before(propagate)) { - synchronize(acquire, propagate); - /* Re-check 'propagate' for mo_graph edges */ - work_queue->push_back(MOEdgeWorkEntry(propagate)); - } - } + + /* Propagate the changed clock vector */ + propagate_clockvector(acquire, work_queue); } else { /* Break release sequence with new edges: * release --mo--> write --mo--> rf */ @@ -1177,9 +1194,10 @@ void ModelExecution::thread_blocking_check_promises(Thread *blocker, Thread *wai /** * @brief Check whether a model action is enabled. * - * Checks whether a lock or join operation would be successful (i.e., is the - * lock already locked, or is the joined thread already complete). If not, put - * the action in a waiter list. + * Checks whether an operation would be successful (i.e., is a lock already + * locked, or is the joined thread already complete). + * + * For yield-blocking, yields are never enabled. * * @param curr is the ModelAction to check whether it is enabled. * @return a bool that indicates whether the action is enabled. @@ -1196,6 +1214,8 @@ bool ModelExecution::check_action_enabled(ModelAction *curr) { thread_blocking_check_promises(blocking, get_thread(curr)); return false; } + } else if (params->yieldblock && curr->is_yield()) { + return false; } return true; @@ -1210,7 +1230,7 @@ bool ModelExecution::check_action_enabled(ModelAction *curr) { * * @param curr The current action to process * @return The ModelAction that is actually executed; may be different than - * curr; may be NULL, if the current action is not enabled to run + * curr */ ModelAction * ModelExecution::check_current_action(ModelAction *curr) { @@ -1253,7 +1273,7 @@ ModelAction * ModelExecution::check_current_action(ModelAction *curr) if (act->is_read() && !second_part_of_rmw && process_read(act)) update = true; - if (act->is_write() && process_write(act)) + if (act->is_write() && process_write(act, &work_queue)) update = true; if (act->is_fence() && process_fence(act)) @@ -2031,6 +2051,37 @@ void ModelExecution::get_release_seq_heads(ModelAction *acquire, } } +/** + * @brief Propagate a modified clock vector to actions later in the execution + * order + * + * After an acquire operation lazily completes a release-sequence + * synchronization, we must update all clock vectors for operations later than + * the acquire in the execution order. + * + * @param acquire The ModelAction whose clock vector must be propagated + * @param work The work queue to which we can add work items, if this + * propagation triggers more updates (e.g., to the modification order) + */ +void ModelExecution::propagate_clockvector(ModelAction *acquire, work_queue_t *work) +{ + /* Re-check all pending release sequences */ + work->push_back(CheckRelSeqWorkEntry(NULL)); + /* Re-check read-acquire for mo_graph edges */ + work->push_back(MOEdgeWorkEntry(acquire)); + + /* propagate synchronization to later actions */ + action_list_t::reverse_iterator rit = action_trace.rbegin(); + for (; (*rit) != acquire; rit++) { + ModelAction *propagate = *rit; + if (acquire->happens_before(propagate)) { + synchronize(acquire, propagate); + /* Re-check 'propagate' for mo_graph edges */ + work->push_back(MOEdgeWorkEntry(propagate)); + } + } +} + /** * Attempt to resolve all stashed operations that might synchronize with a * release sequence for a given location. This implements the "lazy" portion of @@ -2069,22 +2120,8 @@ bool ModelExecution::resolve_release_sequences(void *location, work_queue_t *wor updated = true; if (updated) { - /* Re-check all pending release sequences */ - work_queue->push_back(CheckRelSeqWorkEntry(NULL)); - /* Re-check read-acquire for mo_graph edges */ - if (acquire->is_read()) - work_queue->push_back(MOEdgeWorkEntry(acquire)); - - /* propagate synchronization to later actions */ - action_list_t::reverse_iterator rit = action_trace.rbegin(); - for (; (*rit) != acquire; rit++) { - ModelAction *propagate = *rit; - if (acquire->happens_before(propagate)) { - synchronize(acquire, propagate); - /* Re-check 'propagate' for mo_graph edges */ - work_queue->push_back(MOEdgeWorkEntry(propagate)); - } - } + /* Propagate the changed clock vector */ + propagate_clockvector(acquire, work_queue); } if (complete) { it = pending_rel_seqs.erase(it); @@ -2112,7 +2149,7 @@ void ModelExecution::add_action_to_lists(ModelAction *act) int tid = id_to_int(act->get_tid()); ModelAction *uninit = NULL; int uninit_id = -1; - action_list_t *list = get_safe_ptr_action(obj_map, act->get_location()); + action_list_t *list = get_safe_ptr_action(&obj_map, act->get_location()); if (list->empty() && act->is_atomic_var()) { uninit = get_uninitialized_action(act); uninit_id = id_to_int(uninit->get_tid()); @@ -2145,7 +2182,7 @@ void ModelExecution::add_action_to_lists(ModelAction *act) if (act->is_wait()) { void *mutex_loc = (void *) act->get_value(); - get_safe_ptr_action(obj_map, mutex_loc)->push_back(act); + get_safe_ptr_action(&obj_map, mutex_loc)->push_back(act); SnapVector *vec = get_safe_ptr_vect_action(&obj_thrd_map, mutex_loc); if (tid >= (int)vec->size()) @@ -2193,7 +2230,7 @@ ModelAction * ModelExecution::get_last_fence_release(thread_id_t tid) const ModelAction * ModelExecution::get_last_seq_cst_write(ModelAction *curr) const { void *location = curr->get_location(); - action_list_t *list = get_safe_ptr_action(obj_map, location); + action_list_t *list = obj_map.get(location); /* Find: max({i in dom(S) | seq_cst(t_i) && isWrite(t_i) && samevar(t_i, t)}) */ action_list_t::reverse_iterator rit; for (rit = list->rbegin(); (*rit) != curr; rit++) @@ -2216,7 +2253,11 @@ ModelAction * ModelExecution::get_last_seq_cst_write(ModelAction *curr) const ModelAction * ModelExecution::get_last_seq_cst_fence(thread_id_t tid, const ModelAction *before_fence) const { /* All fences should have location FENCE_LOCATION */ - action_list_t *list = get_safe_ptr_action(obj_map, FENCE_LOCATION); + action_list_t *list = obj_map.get(FENCE_LOCATION); + + if (!list) + return NULL; + action_list_t::reverse_iterator rit = list->rbegin(); if (before_fence) { @@ -2245,7 +2286,7 @@ ModelAction * ModelExecution::get_last_seq_cst_fence(thread_id_t tid, const Mode ModelAction * ModelExecution::get_last_unlock(ModelAction *curr) const { void *location = curr->get_location(); - action_list_t *list = get_safe_ptr_action(obj_map, location); + action_list_t *list = obj_map.get(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++) @@ -2293,15 +2334,20 @@ Promise * ModelExecution::pop_promise_to_resolve(const ModelAction *curr) * Resolve a Promise with a current write. * @param write The ModelAction that is fulfilling Promises * @param promise The Promise to resolve + * @param work The work queue, for adding new fixup work * @return True if the Promise was successfully resolved; false otherwise */ -bool ModelExecution::resolve_promise(ModelAction *write, Promise *promise) +bool ModelExecution::resolve_promise(ModelAction *write, Promise *promise, + work_queue_t *work) { ModelVector actions_to_check; for (unsigned int i = 0; i < promise->get_num_readers(); i++) { ModelAction *read = promise->get_reader(i); - read_from(read, write); + if (read_from(read, write)) { + /* Propagate the changed clock vector */ + propagate_clockvector(read, work); + } actions_to_check.push_back(read); } /* Make sure the promise's value matches the write's value */ @@ -2608,7 +2654,7 @@ void ModelExecution::dumpGraph(char *filename) const 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++) { + for (action_list_t::const_iterator it = action_trace.begin(); it != action_trace.end(); it++) { ModelAction *act = *it; if (act->is_read()) { mo_graph->dot_print_node(file, act); @@ -2651,6 +2697,8 @@ void ModelExecution::print_summary() const model_print("Execution %d:", get_execution_number()); if (isfeasibleprefix()) { + if (is_yieldblocked()) + model_print(" YIELD BLOCKED"); if (scheduler->all_threads_sleeping()) model_print(" SLEEP-SET REDUNDANT"); model_print("\n"); @@ -2675,7 +2723,10 @@ void ModelExecution::print_summary() const */ void ModelExecution::add_thread(Thread *t) { - thread_map.put(id_to_int(t->get_id()), t); + unsigned int i = id_to_int(t->get_id()); + if (i >= thread_map.size()) + thread_map.resize(i + 1); + thread_map[i] = t; if (!t->is_model_thread()) scheduler->add_thread(t); } @@ -2687,7 +2738,10 @@ void ModelExecution::add_thread(Thread *t) */ Thread * ModelExecution::get_thread(thread_id_t tid) const { - return thread_map.get(id_to_int(tid)); + unsigned int i = id_to_int(tid); + if (i < thread_map.size()) + return thread_map[i]; + return NULL; } /** @@ -2802,7 +2856,7 @@ void ModelExecution::fixup_release_sequences() { while (!pending_rel_seqs.empty() && is_feasible_prefix_ignore_relseq() && - !unrealizedraces.empty()) { + haveUnrealizedRaces()) { model_print("*** WARNING: release sequence fixup action " "(%zu pending release seuqence(s)) ***\n", pending_rel_seqs.size());