X-Git-Url: http://plrg.eecs.uci.edu/git/?p=model-checker.git;a=blobdiff_plain;f=model.cc;h=e8b860c2c5058a0daf3f42ada4ba42d470a80b0e;hp=0006fd63d66e172336df1296c417a787fe559d2a;hb=2c830a91c32a55de67c21e03f36529f994d9139d;hpb=c1cc5e279bcba4216bde88a63dafac96d3ef47ba diff --git a/model.cc b/model.cc index 0006fd6..e8b860c 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 @@ -33,7 +34,7 @@ ModelChecker::ModelChecker(struct model_params params) : obj_thrd_map(new HashTable, uintptr_t, 4 >()), promises(new std::vector()), futurevalues(new std::vector()), - pending_acq_rel_seq(new std::vector()), + pending_rel_seqs(new std::vector()), thrd_last_action(new std::vector(1)), node_stack(new NodeStack()), mo_graph(new CycleGraph()), @@ -51,7 +52,7 @@ ModelChecker::ModelChecker(struct model_params params) : /** @brief Destructor */ ModelChecker::~ModelChecker() { - for (int i = 0; i < get_num_threads(); i++) + for (unsigned int i = 0; i < get_num_threads(); i++) delete thread_map->get(i); delete thread_map; @@ -64,7 +65,7 @@ ModelChecker::~ModelChecker() delete (*promises)[i]; delete promises; - delete pending_acq_rel_seq; + delete pending_rel_seqs; delete thrd_last_action; delete node_stack; @@ -94,11 +95,17 @@ thread_id_t ModelChecker::get_next_id() } /** @return the number of user threads created during this execution */ -int ModelChecker::get_num_threads() +unsigned 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() { @@ -171,7 +178,7 @@ Thread * ModelChecker::get_next_thread(ModelAction *curr) } else { tid = next->get_tid(); } - DEBUG("*** ModelChecker chose next thread = %d ***\n", tid); + 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)); } @@ -188,6 +195,7 @@ bool ModelChecker::next_execution() DBG(); num_executions++; + if (isfinalfeasible()) { printf("Earliest divergence point since last feasible execution:\n"); if (earliest_diverge) @@ -199,6 +207,9 @@ bool ModelChecker::next_execution() num_feasible_executions++; } + DEBUG("Number of acquires waiting on pending release sequences: %lu\n", + pending_rel_seqs->size()); + if (isfinalfeasible() || DBG_ENABLED()) print_summary(); @@ -313,7 +324,8 @@ void ModelChecker::set_backtracking(ModelAction *act) if (!node->set_backtrack(tid)) continue; DEBUG("Setting backtrack: conflict = %d, instead tid = %d\n", - prev->get_tid(), t->get_id()); + id_to_int(prev->get_tid()), + id_to_int(t->get_id())); if (DBG_ENABLED()) { prev->print(); act->print(); @@ -365,6 +377,8 @@ bool ModelChecker::process_read(ModelAction *curr, bool second_part_of_rmw) curr->read_from(reads_from); mo_graph->commitChanges(); + mo_check_promises(curr->get_tid(), reads_from); + updated |= r_status; } else if (!second_part_of_rmw) { /* Read from future value */ @@ -430,7 +444,7 @@ bool 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; @@ -462,6 +476,8 @@ bool ModelChecker::process_write(ModelAction *curr) } mo_graph->commitChanges(); + mo_check_promises(curr->get_tid(), curr); + get_thread(curr)->set_return_value(VALUE_NONE); return updated_mod_order || updated_promises; } @@ -475,11 +491,11 @@ 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: { @@ -496,7 +512,7 @@ bool ModelChecker::process_thread_action(ModelAction *curr) scheduler->sleep(waiting); } else { do_complete_join(curr); - synchronized = true; + updated = true; /* trigger rel-seq checks */ } break; } @@ -507,20 +523,21 @@ 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: { - check_promises(NULL, curr->get_cv()); + check_promises(curr->get_tid(), NULL, curr->get_cv()); break; } default: break; } - return synchronized; + return updated; } /** @@ -547,6 +564,8 @@ ModelAction * ModelChecker::initialize_curr_action(ModelAction *curr) 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 */ @@ -619,7 +638,7 @@ 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); } @@ -741,7 +760,7 @@ bool ModelChecker::promises_expired() { /** @return whether the current partial trace must be a prefix of a * feasible trace. */ bool ModelChecker::isfeasibleprefix() { - return promises->size() == 0 && pending_acq_rel_seq->size() == 0; + return promises->size() == 0 && pending_rel_seqs->size() == 0; } /** @return whether the current partial trace is feasible. */ @@ -780,8 +799,7 @@ bool ModelChecker::isfinalfeasible() { /** Close out a RMWR by converting previous RMWR into a RMW or READ. */ ModelAction * ModelChecker::process_rmw(ModelAction *act) { - int tid = id_to_int(act->get_tid()); - ModelAction *lastread = get_last_action(tid); + ModelAction *lastread = get_last_action(act->get_tid()); lastread->process_rmw(act); if (act->is_rmw() && lastread->get_reads_from()!=NULL) { mo_graph->addRMWEdge(lastread->get_reads_from(), lastread); @@ -927,7 +945,11 @@ 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; } @@ -1052,14 +1074,22 @@ 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; } @@ -1076,8 +1106,12 @@ 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) && @@ -1140,13 +1174,19 @@ bool ModelChecker::thin_air_constraint_may_allow(const ModelAction * writer, con * @todo Finish lazy updating, when promises are fulfilled in the future * @param rf The action that might be part of a release sequence. Must be a * write. - * @param release_heads A pass-by-reference style return parameter. After + * @param release_heads A pass-by-reference style return parameter. After * execution of this function, release_heads will contain the heads of all the - * relevant release sequences, if any exists + * relevant release sequences, if any exists with certainty + * @param pending A pass-by-reference style return parameter which is only used + * when returning false (i.e., uncertain). Returns most information regarding + * an uncertain release sequence, including any write operations that might + * break the sequence. * @return true, if the ModelChecker is certain that release_heads is complete; * false otherwise */ -bool ModelChecker::release_seq_head(const ModelAction *rf, rel_heads_list_t *release_heads) const +bool ModelChecker::release_seq_heads(const ModelAction *rf, + rel_heads_list_t *release_heads, + struct release_seq *pending) const { /* Only check for release sequences if there are no cycles */ if (mo_graph->checkForCycles()) @@ -1175,6 +1215,7 @@ bool ModelChecker::release_seq_head(const ModelAction *rf, rel_heads_list_t *rel }; if (!rf) { /* read from future: need to settle this later */ + pending->rf = NULL; return false; /* incomplete */ } @@ -1204,6 +1245,8 @@ bool ModelChecker::release_seq_head(const ModelAction *rf, rel_heads_list_t *rel ASSERT(rf->same_thread(release)); + pending->writes.clear(); + bool certain = true; for (unsigned int i = 0; i < thrd_lists->size(); i++) { if (id_to_int(rf->get_tid()) == (int)i) @@ -1216,7 +1259,7 @@ bool ModelChecker::release_seq_head(const ModelAction *rf, rel_heads_list_t *rel ModelAction *last = get_last_action(int_to_id(i)); if (last && (rf->happens_before(last) || - last->get_type() == THREAD_FINISH)) + get_thread(int_to_id(i))->is_complete())) future_ordered = true; for (rit = list->rbegin(); rit != list->rend(); rit++) { @@ -1247,14 +1290,21 @@ bool ModelChecker::release_seq_head(const ModelAction *rf, rel_heads_list_t *rel /* release --mo-> act --mo--> rf */ return true; /* complete */ } + /* act may break release sequence */ + pending->writes.push_back(act); certain = false; } if (!future_ordered) - return false; /* This thread is uncertain */ + certain = false; /* This thread is uncertain */ } - if (certain) + if (certain) { release_heads->push_back(release); + pending->writes.clear(); + } else { + pending->release = release; + pending->rf = rf; + } return certain; } @@ -1268,16 +1318,19 @@ bool ModelChecker::release_seq_head(const ModelAction *rf, rel_heads_list_t *rel * @param act The 'acquire' action that may read from a release sequence * @param release_heads A pass-by-reference return parameter. Will be filled * with the head(s) of the release sequence(s), if they exists with certainty. - * @see ModelChecker::release_seq_head + * @see ModelChecker::release_seq_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) { + struct release_seq *sequence = (struct release_seq *)snapshot_calloc(1, sizeof(struct release_seq)); + sequence->acquire = act; + + if (!release_seq_heads(rf, release_heads, sequence)) { /* add act to 'lazy checking' list */ - pending_acq_rel_seq->push_back(act); + pending_rel_seqs->push_back(sequence); + } else { + snapshot_free(sequence); } } @@ -1297,9 +1350,10 @@ void ModelChecker::get_release_seq_heads(ModelAction *act, rel_heads_list_t *rel bool ModelChecker::resolve_release_sequences(void *location, work_queue_t *work_queue) { bool updated = false; - std::vector::iterator it = pending_acq_rel_seq->begin(); - while (it != pending_acq_rel_seq->end()) { - ModelAction *act = *it; + std::vector::iterator it = pending_rel_seqs->begin(); + while (it != pending_rel_seqs->end()) { + struct release_seq *pending = *it; + ModelAction *act = pending->acquire; /* Only resolve sequences on the given location, if provided */ if (location && act->get_location() != location) { @@ -1310,7 +1364,7 @@ bool ModelChecker::resolve_release_sequences(void *location, work_queue_t *work_ const ModelAction *rf = act->get_reads_from(); rel_heads_list_t release_heads; bool complete; - complete = release_seq_head(rf, &release_heads); + complete = release_seq_heads(rf, &release_heads, pending); for (unsigned int i = 0; i < release_heads.size(); i++) { if (!act->has_synchronized_with(release_heads[i])) { if (act->synchronize_with(release_heads[i])) @@ -1321,6 +1375,8 @@ bool ModelChecker::resolve_release_sequences(void *location, work_queue_t *work_ } 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)); @@ -1335,10 +1391,12 @@ bool ModelChecker::resolve_release_sequences(void *location, work_queue_t *work_ } } } - if (complete) - it = pending_acq_rel_seq->erase(it); - else + if (complete) { + it = pending_rel_seqs->erase(it); + snapshot_free(pending); + } else { it++; + } } // If we resolved promises or data races, see if we have realized a data race. @@ -1454,6 +1512,7 @@ ClockVector * ModelChecker::get_cv(thread_id_t tid) bool ModelChecker::resolve_promises(ModelAction *write) { bool resolved = false; + std::vector threads_to_check; for (unsigned int i = 0, promise_index = 0; promise_index < promises->size(); i++) { Promise *promise = (*promises)[promise_index]; @@ -1471,12 +1530,18 @@ bool ModelChecker::resolve_promises(ModelAction *write) 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); + threads_to_check.push_back(read->get_tid()); + resolved = true; } else promise_index++; } + for(unsigned int i=0;isize(); i++) { Promise *promise = (*promises)[i]; const ModelAction *act = promise->get_action(); if ((old_cv == NULL || !old_cv->synchronized_since(act)) && merge_cv->synchronized_since(act)) { - //This thread is no longer able to send values back to satisfy the promise - int num_synchronized_threads = promise->increment_threads(); - if (num_synchronized_threads == get_num_threads()) { + if (promise->increment_threads(tid)) { //Promise has failed failed_promise = true; return; @@ -1520,6 +1583,40 @@ void ModelChecker::check_promises(ClockVector *old_cv, ClockVector *merge_cv) } } +/** Checks promises in response to change in ClockVector Threads. */ +void ModelChecker::mo_check_promises(thread_id_t tid, const ModelAction *write) { + void * location = write->get_location(); + for (unsigned int i = 0; i < promises->size(); i++) { + Promise *promise = (*promises)[i]; + const ModelAction *act = promise->get_action(); + + //Is this promise on the same location? + if ( act->get_location() != location ) + continue; + + if ( act->get_tid()==tid) { + if (promise->get_write() == NULL ) { + promise->set_write(write); + } + if (mo_graph->checkPromise(write, promise)) { + failed_promise = true; + return; + } + } + + //Don't do any lookups twice for the same thread + if (promise->has_sync_thread(tid)) + continue; + + if (mo_graph->checkReachable(promise->get_write(), write)) { + if (promise->increment_threads(tid)) { + failed_promise = true; + return; + } + } + } +} + /** * Build up an initial set of all past writes that this 'read' action may read * from. This set is determined by the clock vector's "happens before" @@ -1618,7 +1715,8 @@ void ModelChecker::dumpGraph(char *filename) { 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()); - fprintf(file, "N%u -> N%u[label=\"rf\", color=red];\n", action->get_seq_number(), action->get_reads_from()->get_seq_number()); + 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()); @@ -1674,12 +1772,35 @@ 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) const +{ + 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) const +{ + 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) @@ -1699,7 +1820,7 @@ 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); @@ -1713,22 +1834,23 @@ bool ModelChecker::take_step() { 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); + DEBUG("(%d, %d)\n", curr ? id_to_int(curr->get_id()) : -1, + next ? id_to_int(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);