- if (write_after_read && write_after_read != writer && mo_graph->checkReachable(write_after_read, writer))
- return false;
- }
- return true;
-}
-
-/**
- * Finds the head(s) of the release sequence(s) containing a given ModelAction.
- * The ModelAction under consideration is expected to be taking part in
- * release/acquire synchronization as an object of the "reads from" relation.
- * Note that this can only provide release sequence support for RMW chains
- * which do not read from the future, as those actions cannot be traced until
- * their "promise" is fulfilled. Similarly, we may not even establish the
- * presence of a release sequence with certainty, as some modification order
- * constraints may be decided further in the future. Thus, this function
- * "returns" two pieces of data: a pass-by-reference vector of @a release_heads
- * and a boolean representing certainty.
- *
- * @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
- * execution of this function, release_heads will contain the heads of all the
- * 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_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())
- return false;
-
- for ( ; rf != NULL; rf = rf->get_reads_from()) {
- ASSERT(rf->is_write());
-
- if (rf->is_release())
- release_heads->push_back(rf);
- else if (rf->get_last_fence_release())
- release_heads->push_back(rf->get_last_fence_release());
- if (!rf->is_rmw())
- break; /* End of RMW chain */
-
- /** @todo Need to be smarter here... In the linux lock
- * example, this will run to the beginning of the program for
- * every acquire. */
- /** @todo The way to be smarter here is to keep going until 1
- * thread has a release preceded by an acquire and you've seen
- * both. */
-
- /* acq_rel RMW is a sufficient stopping condition */
- if (rf->is_acquire() && rf->is_release())
- return true; /* complete */
- };
- if (!rf) {
- /* read from future: need to settle this later */
- pending->rf = NULL;
- return false; /* incomplete */
- }
-
- if (rf->is_release())
- return true; /* complete */
-
- /* else relaxed write
- * - check for fence-release in the same thread (29.8, stmt. 3)
- * - check modification order for contiguous subsequence
- * -> rf must be same thread as release */
-
- const ModelAction *fence_release = rf->get_last_fence_release();
- /* Synchronize with a fence-release unconditionally; we don't need to
- * find any more "contiguous subsequence..." for it */
- if (fence_release)
- release_heads->push_back(fence_release);
-
- int tid = id_to_int(rf->get_tid());
- std::vector<action_list_t> *thrd_lists = get_safe_ptr_vect_action(obj_thrd_map, rf->get_location());
- action_list_t *list = &(*thrd_lists)[tid];
- action_list_t::const_reverse_iterator rit;
-
- /* Find rf in the thread list */
- rit = std::find(list->rbegin(), list->rend(), rf);
- ASSERT(rit != list->rend());
-
- /* Find the last {write,fence}-release */
- for (; rit != list->rend(); rit++) {
- if (fence_release && *(*rit) < *fence_release)
- break;
- if ((*rit)->is_release())
- break;
- }
- if (rit == list->rend()) {
- /* No write-release in this thread */
- return true; /* complete */
- } else if (fence_release && *(*rit) < *fence_release) {
- /* The fence-release is more recent (and so, "stronger") than
- * the most recent write-release */
- return true; /* complete */
- } /* else, need to establish contiguous release sequence */
- ModelAction *release = *rit;
-
- 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)
- continue;
- list = &(*thrd_lists)[i];
-
- /* Can we ensure no future writes from this thread may break
- * the release seq? */
- bool future_ordered = false;
-
- ModelAction *last = get_last_action(int_to_id(i));
- Thread *th = get_thread(int_to_id(i));
- if ((last && rf->happens_before(last)) ||
- !is_enabled(th) ||
- th->is_complete())
- future_ordered = true;
-
- ASSERT(!th->is_model_thread() || future_ordered);
-
- for (rit = list->rbegin(); rit != list->rend(); rit++) {
- const ModelAction *act = *rit;
- /* Reach synchronization -> this thread is complete */
- if (act->happens_before(release))
- break;
- if (rf->happens_before(act)) {
- future_ordered = true;
- continue;
- }
-
- /* Only non-RMW writes can break release sequences */
- if (!act->is_write() || act->is_rmw())
- continue;
-
- /* Check modification order */
- if (mo_graph->checkReachable(rf, act)) {
- /* rf --mo--> act */
- future_ordered = true;
- continue;
- }
- if (mo_graph->checkReachable(act, release))
- /* act --mo--> release */
- break;
- if (mo_graph->checkReachable(release, act) &&
- mo_graph->checkReachable(act, rf)) {
- /* release --mo-> act --mo--> rf */
- return true; /* complete */
- }
- /* act may break release sequence */
- pending->writes.push_back(act);
- certain = false;
- }
- if (!future_ordered)
- certain = false; /* This thread is uncertain */
- }
-
- if (certain) {
- release_heads->push_back(release);
- pending->writes.clear();
- } else {
- pending->release = release;
- pending->rf = rf;
- }
- return certain;
-}
-
-/**
- * An interface for getting the release sequence head(s) with which a
- * given ModelAction must synchronize. This function only returns a non-empty
- * result when it can locate a release sequence head with certainty. Otherwise,
- * it may mark the internal state of the ModelChecker so that it will handle
- * the release sequence at a later time, causing @a acquire to update its
- * synchronization at some later point in execution.
- *
- * @param acquire The 'acquire' action that may synchronize with a release
- * sequence
- * @param read The read action that may read from a release sequence; this may
- * be the same as acquire, or else an earlier action in the same thread (i.e.,
- * when 'acquire' is a fence-acquire)
- * @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_heads
- */
-void ModelChecker::get_release_seq_heads(ModelAction *acquire,
- ModelAction *read, rel_heads_list_t *release_heads)
-{
- const ModelAction *rf = read->get_reads_from();
- struct release_seq *sequence = (struct release_seq *)snapshot_calloc(1, sizeof(struct release_seq));
- sequence->acquire = acquire;
- sequence->read = read;
-
- if (!release_seq_heads(rf, release_heads, sequence)) {
- /* add act to 'lazy checking' list */
- pending_rel_seqs->push_back(sequence);
- } else {
- snapshot_free(sequence);
- }
-}
-
-/**
- * Attempt to resolve all stashed operations that might synchronize with a
- * release sequence for a given location. This implements the "lazy" portion of
- * determining whether or not a release sequence was contiguous, since not all
- * modification order information is present at the time an action occurs.
- *
- * @param location The location/object that should be checked for release
- * sequence resolutions. A NULL value means to check all locations.
- * @param work_queue The work queue to which to add work items as they are
- * generated
- * @return True if any updates occurred (new synchronization, new mo_graph
- * edges)
- */
-bool ModelChecker::resolve_release_sequences(void *location, work_queue_t *work_queue)
-{
- bool updated = false;
- std::vector< struct release_seq *, SnapshotAlloc<struct release_seq *> >::iterator it = pending_rel_seqs->begin();
- while (it != pending_rel_seqs->end()) {
- struct release_seq *pending = *it;
- ModelAction *acquire = pending->acquire;
- const ModelAction *read = pending->read;
-
- /* Only resolve sequences on the given location, if provided */
- if (location && read->get_location() != location) {
- it++;
- continue;
- }
-
- const ModelAction *rf = read->get_reads_from();
- rel_heads_list_t release_heads;
- bool complete;
- complete = release_seq_heads(rf, &release_heads, pending);
- for (unsigned int i = 0; i < release_heads.size(); i++) {
- if (!acquire->has_synchronized_with(release_heads[i])) {
- if (acquire->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 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)) {
- propagate->synchronize_with(acquire);
- /* Re-check 'propagate' for mo_graph edges */
- work_queue->push_back(MOEdgeWorkEntry(propagate));
- }
- }
- }
- 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.
- checkDataRaces();
-
- return updated;
-}
-
-/**
- * Performs various bookkeeping operations for the current ModelAction. For
- * instance, adds action to the per-object, per-thread action vector and to the
- * action trace list of all thread actions.
- *
- * @param act is the ModelAction to add.
- */
-void ModelChecker::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());
- if (list->empty() && act->is_atomic_var()) {
- uninit = new_uninitialized_action(act->get_location());
- uninit_id = id_to_int(uninit->get_tid());
- list->push_back(uninit);
- }
- list->push_back(act);
-
- action_trace->push_back(act);
- if (uninit)
- action_trace->push_front(uninit);
-
- std::vector<action_list_t> *vec = get_safe_ptr_vect_action(obj_thrd_map, act->get_location());
- if (tid >= (int)vec->size())
- vec->resize(priv->next_thread_id);
- (*vec)[tid].push_back(act);
- if (uninit)
- (*vec)[uninit_id].push_front(uninit);
-
- if ((int)thrd_last_action->size() <= tid)
- thrd_last_action->resize(get_num_threads());
- (*thrd_last_action)[tid] = act;
- if (uninit)
- (*thrd_last_action)[uninit_id] = uninit;
-
- if (act->is_fence() && act->is_release()) {
- if ((int)thrd_last_fence_release->size() <= tid)
- thrd_last_fence_release->resize(get_num_threads());
- (*thrd_last_fence_release)[tid] = act;
- }
-
- if (act->is_wait()) {
- void *mutex_loc = (void *) act->get_value();
- get_safe_ptr_action(obj_map, mutex_loc)->push_back(act);
-
- std::vector<action_list_t> *vec = get_safe_ptr_vect_action(obj_thrd_map, mutex_loc);
- if (tid >= (int)vec->size())
- vec->resize(priv->next_thread_id);
- (*vec)[tid].push_back(act);
- }
-}
-
-/**
- * @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 threadid = id_to_int(tid);
- if (threadid < (int)thrd_last_action->size())
- return (*thrd_last_action)[id_to_int(tid)];
- else
- return NULL;
-}
-
-/**
- * @brief Get the last fence release performed by a particular Thread
- * @param tid The thread ID of the Thread in question
- * @return The last fence release in the thread, if one exists; NULL otherwise
- */
-ModelAction * ModelChecker::get_last_fence_release(thread_id_t tid) const
-{
- int threadid = id_to_int(tid);
- if (threadid < (int)thrd_last_fence_release->size())
- return (*thrd_last_fence_release)[id_to_int(tid)];
- else
- return NULL;
-}
-
-/**
- * Gets the last memory_order_seq_cst write (in the total global sequence)
- * performed on a particular object (i.e., memory location), not including the
- * current action.
- * @param curr The current ModelAction; also denotes the object location to
- * check
- * @return The last seq_cst write
- */
-ModelAction * ModelChecker::get_last_seq_cst_write(ModelAction *curr) const
-{
- void *location = curr->get_location();
- action_list_t *list = get_safe_ptr_action(obj_map, 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 != list->rend(); rit++)
- if ((*rit)->is_write() && (*rit)->is_seqcst() && (*rit) != curr)
- return *rit;
- return NULL;
-}
-
-/**
- * Gets the last memory_order_seq_cst fence (in the total global sequence)
- * performed in a particular thread, prior to a particular fence.
- * @param tid The ID of the thread to check
- * @param before_fence The fence from which to begin the search; if NULL, then
- * search for the most recent fence in the thread.
- * @return The last prior seq_cst fence in the thread, if exists; otherwise, NULL
- */
-ModelAction * ModelChecker::get_last_seq_cst_fence(thread_id_t tid, const ModelAction *before_fence) const
-{
- /* All fences should have NULL location */
- action_list_t *list = get_safe_ptr_action(obj_map, NULL);
- action_list_t::reverse_iterator rit = list->rbegin();
-
- if (before_fence) {
- for (; rit != list->rend(); rit++)
- if (*rit == before_fence)
- break;
-
- ASSERT(*rit == before_fence);
- rit++;
- }
-
- for (; rit != list->rend(); rit++)
- if ((*rit)->is_fence() && (tid == (*rit)->get_tid()) && (*rit)->is_seqcst())
- return *rit;
- 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 = get_safe_ptr_action(obj_map, 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() || (*rit)->is_wait())
- return *rit;
- return NULL;
-}
-
-ModelAction * ModelChecker::get_parent_action(thread_id_t tid) const
-{
- ModelAction *parent = get_last_action(tid);
- if (!parent)
- parent = get_thread(tid)->get_creation();
- return parent;
-}
-
-/**
- * Returns the clock vector for a given thread.
- * @param tid The thread whose clock vector we want
- * @return Desired clock vector
- */
-ClockVector * ModelChecker::get_cv(thread_id_t tid) const
-{
- return get_parent_action(tid)->get_cv();
-}
-
-/**
- * @brief Find the promise, if any to resolve for the current action
- * @param curr The current ModelAction. Should be a write.
- * @return The (non-negative) index for the Promise to resolve, if any;
- * otherwise -1
- */
-int ModelChecker::get_promise_to_resolve(const ModelAction *curr) const
-{
- for (unsigned int i = 0; i < promises->size(); i++)
- if (curr->get_node()->get_promise(i))
- return i;
- return -1;
-}
-
-/**
- * Resolve a Promise with a current write.
- * @param write The ModelAction that is fulfilling Promises
- * @param promise_idx The index corresponding to the promise
- * @return True if the Promise was successfully resolved; false otherwise
- */
-bool ModelChecker::resolve_promise(ModelAction *write, unsigned int promise_idx)
-{
- std::vector< ModelAction *, ModelAlloc<ModelAction *> > actions_to_check;
- Promise *promise = (*promises)[promise_idx];
-
- for (unsigned int i = 0; i < promise->get_num_readers(); i++) {
- ModelAction *read = promise->get_reader(i);
- read_from(read, write);
- actions_to_check.push_back(read);
- }
- /* Make sure the promise's value matches the write's value */
- ASSERT(promise->is_compatible(write) && promise->same_value(write));
- if (!mo_graph->resolvePromise(promise, write))
- priv->failed_promise = true;
-
- promises->erase(promises->begin() + promise_idx);
- /**
- * @todo It is possible to end up in an inconsistent state, where a
- * "resolved" promise may still be referenced if
- * CycleGraph::resolvePromise() failed, so don't delete 'promise'.
- *
- * Note that the inconsistency only matters when dumping mo_graph to
- * file.
- *
- * delete promise;
- */
-
- //Check whether reading these writes has made threads unable to
- //resolve promises
- for (unsigned int i = 0; i < actions_to_check.size(); i++) {
- ModelAction *read = actions_to_check[i];
- mo_check_promises(read, true);
- }
-
- return true;
-}
-
-/**
- * Compute the set of promises that could potentially be satisfied by this
- * action. Note that the set computation actually appears in the Node, not in
- * ModelChecker.
- * @param curr The ModelAction that may satisfy promises
- */
-void ModelChecker::compute_promises(ModelAction *curr)
-{
- for (unsigned int i = 0; i < promises->size(); i++) {
- Promise *promise = (*promises)[i];
- if (!promise->is_compatible(curr) || !promise->same_value(curr))
- continue;
-
- bool satisfy = true;
- for (unsigned int j = 0; j < promise->get_num_readers(); j++) {
- const ModelAction *act = promise->get_reader(j);
- if (act->happens_before(curr) ||
- act->could_synchronize_with(curr)) {
- satisfy = false;
- break;
- }
- }
- if (satisfy)
- curr->get_node()->set_promise(i);
- }
-}
-
-/** Checks promises in response to change in ClockVector Threads. */
-void ModelChecker::check_promises(thread_id_t tid, ClockVector *old_cv, ClockVector *merge_cv)
-{
- for (unsigned int i = 0; i < promises->size(); i++) {
- Promise *promise = (*promises)[i];
- if (!promise->thread_is_available(tid))
- continue;
- for (unsigned int j = 0; j < promise->get_num_readers(); j++) {
- const ModelAction *act = promise->get_reader(j);
- if ((!old_cv || !old_cv->synchronized_since(act)) &&
- merge_cv->synchronized_since(act)) {
- if (promise->eliminate_thread(tid)) {
- /* Promise has failed */
- priv->failed_promise = true;
- return;
- }
- }
- }
- }
-}
-
-void ModelChecker::check_promises_thread_disabled()
-{
- for (unsigned int i = 0; i < promises->size(); i++) {
- Promise *promise = (*promises)[i];
- if (promise->has_failed()) {
- priv->failed_promise = true;
- return;
- }
- }
-}
-
-/**
- * @brief Checks promises in response to addition to modification order for
- * threads.
- *
- * We test whether threads are still available for satisfying promises after an
- * addition to our modification order constraints. Those that are unavailable
- * are "eliminated". Once all threads are eliminated from satisfying a promise,
- * that promise has failed.
- *
- * @param act The ModelAction which updated the modification order
- * @param is_read_check Should be true if act is a read and we must check for
- * updates to the store from which it read (there is a distinction here for
- * RMW's, which are both a load and a store)
- */
-void ModelChecker::mo_check_promises(const ModelAction *act, bool is_read_check)
-{
- const ModelAction *write = is_read_check ? act->get_reads_from() : act;
-
- for (unsigned int i = 0; i < promises->size(); i++) {
- Promise *promise = (*promises)[i];
-
- // Is this promise on the same location?
- if (!promise->same_location(write))
- continue;
-
- for (unsigned int j = 0; j < promise->get_num_readers(); j++) {
- const ModelAction *pread = promise->get_reader(j);
- if (!pread->happens_before(act))
- continue;
- if (mo_graph->checkPromise(write, promise)) {
- priv->failed_promise = true;
- return;
- }
- break;
- }
-
- // Don't do any lookups twice for the same thread
- if (!promise->thread_is_available(act->get_tid()))
- continue;
-
- if (mo_graph->checkReachable(promise, write)) {
- if (mo_graph->checkPromise(write, promise)) {
- priv->failed_promise = true;
- return;
- }
- }
- }
-}
-
-/**
- * Compute the set of writes that may break the current pending release
- * sequence. This information is extracted from previou release sequence
- * calculations.
- *
- * @param curr The current ModelAction. Must be a release sequence fixup
- * action.
- */
-void ModelChecker::compute_relseq_breakwrites(ModelAction *curr)
-{
- if (pending_rel_seqs->empty())
- return;
-
- struct release_seq *pending = pending_rel_seqs->back();
- for (unsigned int i = 0; i < pending->writes.size(); i++) {
- const ModelAction *write = pending->writes[i];
- curr->get_node()->add_relseq_break(write);
- }
-
- /* NULL means don't break the sequence; just synchronize */
- curr->get_node()->add_relseq_break(NULL);
-}
-
-/**
- * Build up an initial set of all past writes that this 'read' action may read
- * from, as well as any previously-observed future values that must still be valid.
- *
- * @param curr is the current ModelAction that we are exploring; it must be a
- * 'read' operation.
- */
-void ModelChecker::build_may_read_from(ModelAction *curr)
-{
- std::vector<action_list_t> *thrd_lists = get_safe_ptr_vect_action(obj_thrd_map, curr->get_location());
- unsigned int i;
- ASSERT(curr->is_read());
-
- ModelAction *last_sc_write = NULL;
-
- if (curr->is_seqcst())
- last_sc_write = get_last_seq_cst_write(curr);
-
- /* Iterate over all threads */
- for (i = 0; i < thrd_lists->size(); i++) {
- /* Iterate over actions in thread, starting from most recent */
- action_list_t *list = &(*thrd_lists)[i];
- action_list_t::reverse_iterator rit;
- for (rit = list->rbegin(); rit != list->rend(); rit++) {
- ModelAction *act = *rit;
-
- /* Only consider 'write' actions */
- if (!act->is_write() || act == curr)
- continue;
-
- /* Don't consider more than one seq_cst write if we are a seq_cst read. */
- bool allow_read = true;
-
- if (curr->is_seqcst() && (act->is_seqcst() || (last_sc_write != NULL && act->happens_before(last_sc_write))) && act != last_sc_write)
- allow_read = false;
- else if (curr->get_sleep_flag() && !curr->is_seqcst() && !sleep_can_read_from(curr, act))
- allow_read = false;
-
- if (allow_read) {
- /* Only add feasible reads */
- mo_graph->startChanges();
- r_modification_order(curr, act);
- if (!is_infeasible())
- curr->get_node()->add_read_from_past(act);
- mo_graph->rollbackChanges();
- }
-
- /* Include at most one act per-thread that "happens before" curr */
- if (act->happens_before(curr))
- break;
- }
- }
-
- /* Inherit existing, promised future values */
- for (i = 0; i < promises->size(); i++) {
- const Promise *promise = (*promises)[i];
- const ModelAction *promise_read = promise->get_reader(0);
- if (promise_read->same_var(curr)) {
- /* Only add feasible future-values */
- mo_graph->startChanges();
- r_modification_order(curr, promise);
- if (!is_infeasible())
- curr->get_node()->add_read_from_promise(promise_read);
- mo_graph->rollbackChanges();
- }
- }
-
- /* We may find no valid may-read-from only if the execution is doomed */
- if (!curr->get_node()->read_from_size()) {
- priv->no_valid_reads = true;
- set_assert();
- }
-
- if (DBG_ENABLED()) {
- model_print("Reached read action:\n");
- curr->print();
- model_print("Printing read_from_past\n");
- curr->get_node()->print_read_from_past();
- model_print("End printing read_from_past\n");
- }
-}
-
-bool ModelChecker::sleep_can_read_from(ModelAction *curr, const ModelAction *write)
-{
- for ( ; write != NULL; write = write->get_reads_from()) {
- /* UNINIT actions don't have a Node, and they never sleep */
- if (write->is_uninitialized())
- return true;
- Node *prevnode = write->get_node()->get_parent();
-
- bool thread_sleep = prevnode->enabled_status(curr->get_tid()) == THREAD_SLEEP_SET;
- if (write->is_release() && thread_sleep)
- return true;
- if (!write->is_rmw())
- return false;
- }
- return true;
-}
-
-/**
- * @brief Create a new action representing an uninitialized atomic
- * @param location The memory location of the atomic object
- * @return A pointer to a new ModelAction
- */
-ModelAction * ModelChecker::new_uninitialized_action(void *location) const
-{
- ModelAction *act = (ModelAction *)snapshot_malloc(sizeof(class ModelAction));
- act = new (act) ModelAction(ATOMIC_UNINIT, std::memory_order_relaxed, location, 0, model_thread);
- act->create_cv(NULL);
- return act;
-}
-
-static void print_list(action_list_t *list)
-{
- action_list_t::iterator it;
-
- model_print("---------------------------------------------------------------------\n");
-
- unsigned int hash = 0;
-
- for (it = list->begin(); it != list->end(); it++) {
- (*it)->print();
- hash = hash^(hash<<3)^((*it)->hash());
- }
- model_print("HASH %u\n", hash);
- model_print("---------------------------------------------------------------------\n");
-}
-
-#if SUPPORT_MOD_ORDER_DUMP
-void ModelChecker::dumpGraph(char *filename) const
-{
- 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 *act = *it;
- if (act->is_read()) {
- mo_graph->dot_print_node(file, act);
- if (act->get_reads_from())
- mo_graph->dot_print_edge(file,
- act->get_reads_from(),
- act,
- "label=\"rf\", color=red, weight=2");
- else
- mo_graph->dot_print_edge(file,
- act->get_reads_from_promise(),
- act,
- "label=\"rf\", color=red");
- }
- if (thread_array[act->get_tid()]) {
- mo_graph->dot_print_edge(file,
- thread_array[id_to_int(act->get_tid())],
- act,
- "label=\"sb\", color=blue, weight=400");
- }
-
- thread_array[act->get_tid()] = act;
- }
- fprintf(file, "}\n");
- model_free(thread_array);
- fclose(file);
-}
-#endif
-
-/** @brief Prints an execution trace summary. */
-void ModelChecker::print_summary() const
-{
-#if SUPPORT_MOD_ORDER_DUMP
- char buffername[100];
- sprintf(buffername, "exec%04u", stats.num_total);
- mo_graph->dumpGraphToFile(buffername);
- sprintf(buffername, "graph%04u", stats.num_total);
- dumpGraph(buffername);
-#endif
-
- model_print("Execution %d:", stats.num_total);
- if (isfeasibleprefix()) {
- if (scheduler->all_threads_sleeping())
- model_print(" SLEEP-SET REDUNDANT");
- model_print("\n");
- } else
- print_infeasibility(" INFEASIBLE");
- print_list(action_trace);
- model_print("\n");
-}
-
-/**
- * Add a Thread to the system for the first time. Should only be called once
- * per thread.
- * @param t The Thread to add
- */
-void ModelChecker::add_thread(Thread *t)
-{
- thread_map->put(id_to_int(t->get_id()), t);
- scheduler->add_thread(t);
-}
-
-/**
- * Removes a thread from the scheduler.
- * @param the thread to remove.
- */
-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(const ModelAction *act) const
-{
- return get_thread(act->get_tid());
-}
-
-/**
- * @brief Get a Promise's "promise number"
- *
- * A "promise number" is an index number that is unique to a promise, valid
- * only for a specific snapshot of an execution trace. Promises may come and go
- * as they are generated an resolved, so an index only retains meaning for the
- * current snapshot.
- *
- * @param promise The Promise to check
- * @return The promise index, if the promise still is valid; otherwise -1
- */
-int ModelChecker::get_promise_number(const Promise *promise) const
-{
- for (unsigned int i = 0; i < promises->size(); i++)
- if ((*promises)[i] == promise)
- return i;
- /* Not found */
- return -1;
-}
-
-/**
- * @brief Check if a Thread is currently enabled
- * @param t The Thread to check
- * @return True if the Thread is currently enabled
- */
-bool ModelChecker::is_enabled(Thread *t) const
-{
- return scheduler->is_enabled(t);
-}
-
-/**
- * @brief Check if a Thread is currently enabled
- * @param tid The ID of the Thread to check
- * @return True if the Thread is currently enabled
- */
-bool ModelChecker::is_enabled(thread_id_t tid) const
-{
- return scheduler->is_enabled(tid);
-}
-
-/**
- * Switch from a model-checker context to a user-thread context. This is the
- * complement of ModelChecker::switch_to_master and must be called from the
- * model-checker context
- *
- * @param thread The user-thread to switch to
- */
-void ModelChecker::switch_from_master(Thread *thread)
-{
- scheduler->set_current_thread(thread);
- Thread::swap(&system_context, thread);
-}
-
-/**
- * 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. May be NULL only if
- * trace is exiting via an assertion (see ModelChecker::set_assert and
- * ModelChecker::has_asserted).
- * @return Return the value returned by the current action
- */
-uint64_t ModelChecker::switch_to_master(ModelAction *act)
-{
- DBG();
- Thread *old = thread_current();
- ASSERT(!old->get_pending());
- old->set_pending(act);
- if (Thread::swap(old, &system_context) < 0) {
- perror("swap threads");
- exit(EXIT_FAILURE);
- }
- return old->get_return_value();
-}
-
-/**
- * Takes the next step in the execution, if possible.
- * @param curr The current step to take
- * @return Returns the next Thread to run, if any; NULL if this execution
- * should terminate
- */
-Thread * ModelChecker::take_step(ModelAction *curr)
-{
- Thread *curr_thrd = get_thread(curr);
- ASSERT(curr_thrd->get_state() == THREAD_READY);
-
- 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;
-
- if (curr_thrd->is_blocked() || curr_thrd->is_complete())
- scheduler->remove_thread(curr_thrd);
-
- Thread *next_thrd = get_next_thread(curr);
-
- 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;
-}
-
-/** Wrapper to run the user's main function, with appropriate arguments */
-void user_main_wrapper(void *)
-{
- user_main(model->params.argc, model->params.argv);
-}
-
-/** @brief Run ModelChecker for the user program */
-void ModelChecker::run()
-{
- do {
- thrd_t user_thread;
- Thread *t = new Thread(&user_thread, &user_main_wrapper, NULL, NULL);
- add_thread(t);
-
- do {
- /*
- * Stash next pending action(s) for thread(s). There
- * should only need to stash one thread's action--the
- * thread which just took a step--plus the first step
- * for any newly-created thread
- */
- for (unsigned int i = 0; i < get_num_threads(); i++) {
- thread_id_t tid = int_to_id(i);
- Thread *thr = get_thread(tid);
- if (!thr->is_model_thread() && !thr->is_complete() && !thr->get_pending()) {
- switch_from_master(thr);
- }
- }
-
- /* Catch assertions from prior take_step or from
- * between-ModelAction bugs (e.g., data races) */
- if (has_asserted())
- 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());
-
- /*
- * Launch end-of-execution release sequence fixups only when
- * the execution is otherwise feasible AND there are:
- *
- * (1) pending release sequences
- * (2) pending assertions that could be invalidated by a change
- * in clock vectors (i.e., data races)
- * (3) no pending promises
- */
- while (!pending_rel_seqs->empty() &&
- is_feasible_prefix_ignore_relseq() &&
- !unrealizedraces.empty()) {
- model_print("*** WARNING: release sequence fixup action "
- "(%zu pending release seuqence(s)) ***\n",
- pending_rel_seqs->size());
- ModelAction *fixup = new ModelAction(MODEL_FIXUP_RELSEQ,
- std::memory_order_seq_cst, NULL, VALUE_NONE,
- model_thread);
- take_step(fixup);
- };
- } while (next_execution());
-
- model_print("******* Model-checking complete: *******\n");
- print_stats();