model: flatten "pending acquire/release sequence" structure
[c11tester.git] / model.cc
index d2fc366cc77d88521d583558aa50d9680df9305e..e4757bc6f0d0b919417e60ed9018e0bcd0e86301 100644 (file)
--- a/model.cc
+++ b/model.cc
@@ -32,7 +32,7 @@ ModelChecker::ModelChecker(struct model_params params) :
        obj_thrd_map(new HashTable<void *, std::vector<action_list_t>, uintptr_t, 4 >()),
        promises(new std::vector<Promise *>()),
        futurevalues(new std::vector<struct PendingFutureValue>()),
-       lazy_sync_with_release(new HashTable<void *, action_list_t, uintptr_t, 4>()),
+       pending_acq_rel_seq(new std::vector<ModelAction *>()),
        thrd_last_action(new std::vector<ModelAction *>(1)),
        node_stack(new NodeStack()),
        mo_graph(new CycleGraph()),
@@ -44,8 +44,6 @@ ModelChecker::ModelChecker(struct model_params params) :
        priv = (struct model_snapshot_members *)calloc(1, sizeof(*priv));
        /* First thread created will have id INITIAL_THREAD_ID */
        priv->next_thread_id = INITIAL_THREAD_ID;
-
-       lazy_sync_size = &priv->lazy_sync_size;
 }
 
 /** @brief Destructor */
@@ -64,7 +62,7 @@ ModelChecker::~ModelChecker()
                delete (*promises)[i];
        delete promises;
 
-       delete lazy_sync_with_release;
+       delete pending_acq_rel_seq;
 
        delete thrd_last_action;
        delete node_stack;
@@ -243,6 +241,13 @@ ModelAction * ModelChecker::get_last_conflict(ModelAction *act)
        return NULL;
 }
 
+/** This method find backtracking points where we should try to
+ * reorder the parameter ModelAction against.
+ *
+ * @param the ModelAction to find backtracking points for.
+ */
+
+
 void ModelChecker::set_backtracking(ModelAction *act)
 {
        Thread *t = get_thread(act);
@@ -254,26 +259,26 @@ void ModelChecker::set_backtracking(ModelAction *act)
 
        int low_tid, high_tid;
        if (node->is_enabled(t)) {
-               low_tid=id_to_int(act->get_tid());
-               high_tid=low_tid+1;
+               low_tid = id_to_int(act->get_tid());
+               high_tid = low_tid+1;
        } else {
-               low_tid=0;
-               high_tid=get_num_threads();
+               low_tid = 0;
+               high_tid = get_num_threads();
        }
-       
-       for(int i=low_tid;i<high_tid;i++) {
-               thread_id_t tid=int_to_id(i);
+
+       for(int i = low_tid; i < high_tid; i++) {
+               thread_id_t tid = int_to_id(i);
                if (!node->is_enabled(tid))
                        continue;
 
                /* Check if this has been explored already */
                if (node->has_been_explored(tid))
                        continue;
-               
+
                /* Cache the latest backtracking point */
                if (!priv->next_backtrack || *prev > *priv->next_backtrack)
                        priv->next_backtrack = prev;
-               
+
                /* If this is a new backtracking point, mark the tree */
                if (!node->set_backtrack(tid))
                        continue;
@@ -346,7 +351,7 @@ bool ModelChecker::process_read(ModelAction *curr, bool second_part_of_rmw)
 
 /**
  * Processes a lock, trylock, or unlock model action.  @param curr is
- * the read model action to process.  
+ * the read model action to process.
  *
  * The try lock operation checks whether the lock is taken.  If not,
  * it falls to the normal lock operation case.  If so, it returns
@@ -358,13 +363,12 @@ 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.
  */
-
 void 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()) {
+       std::mutex *mutex = (std::mutex *)curr->get_location();
+       struct std::mutex_state *state = mutex->get_state();
+       switch (curr->get_type()) {
        case ATOMIC_TRYLOCK: {
-               bool success=!state->islocked;
+               bool success = !state->islocked;
                curr->set_try_lock(success);
                if (!success) {
                        get_thread(curr)->set_return_value(0);
@@ -374,24 +378,24 @@ void ModelChecker::process_mutex(ModelAction *curr) {
        }
                //otherwise fall into the lock case
        case ATOMIC_LOCK: {
-               if (curr->get_cv()->getClock(state->alloc_tid)<=state->alloc_clock) {
+               if (curr->get_cv()->getClock(state->alloc_tid) <= state->alloc_clock) {
                        printf("Lock access before initialization\n");
                        set_assert();
                }
-               state->islocked=true;
-               ModelAction *unlock=get_last_unlock(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);
                break;
        }
        case ATOMIC_UNLOCK: {
                //unlock the lock
-               state->islocked=false;
+               state->islocked = false;
                //wake up the other threads
-               action_list_t * waiters = lock_waiters_map->get_safe_ptr(curr->get_location());
+               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++) {
+               for (action_list_t::iterator rit = waiters->begin(); rit != waiters->end(); rit++) {
                        scheduler->add_thread(get_thread((*rit)->get_tid()));
                }
                waiters->clear();
@@ -402,7 +406,6 @@ void ModelChecker::process_mutex(ModelAction *curr) {
        }
 }
 
-
 /**
  * Process a write ModelAction
  * @param curr The ModelAction to process
@@ -414,7 +417,7 @@ bool ModelChecker::process_write(ModelAction *curr)
        bool updated_promises = resolve_promises(curr);
 
        if (promises->size() == 0) {
-               for (unsigned int i = 0; i<futurevalues->size(); i++) {
+               for (unsigned int i = 0; i < futurevalues->size(); i++) {
                        struct PendingFutureValue pfv = (*futurevalues)[i];
                        if (pfv.act->get_node()->add_future_value(pfv.value, pfv.expiration) &&
                                        (!priv->next_backtrack || *pfv.act > *priv->next_backtrack))
@@ -456,7 +459,7 @@ ModelAction * ModelChecker::initialize_curr_action(ModelAction *curr)
                if (curr->is_rmwr())
                        newcurr->copy_typeandorder(curr);
 
-               ASSERT(curr->get_location()==newcurr->get_location());
+               ASSERT(curr->get_location() == newcurr->get_location());
                newcurr->copy_from_new(curr);
 
                /* Discard duplicate ModelAction; use action from NodeStack */
@@ -488,7 +491,7 @@ ModelAction * ModelChecker::initialize_curr_action(ModelAction *curr)
 
 bool ModelChecker::check_action_enabled(ModelAction *curr) {
        if (curr->is_lock()) {
-               std::mutex * lock=(std::mutex *) curr->get_location();
+               std::mutex * lock = (std::mutex *)curr->get_location();
                struct std::mutex_state * state = lock->get_state();
                if (state->islocked) {
                        //Stick the action in the appropriate waiting queue
@@ -591,7 +594,7 @@ Thread * ModelChecker::check_current_action(ModelAction *curr)
                        if (act->is_write() && process_write(act))
                                updated = true;
 
-                       if (act->is_mutex_op()) 
+                       if (act->is_mutex_op())
                                process_mutex(act);
 
                        if (updated)
@@ -672,7 +675,7 @@ 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 && *lazy_sync_size == 0;
+       return promises->size() == 0 && pending_acq_rel_seq->size() == 0;
 }
 
 /** @return whether the current partial trace is feasible. */
@@ -812,7 +815,7 @@ void ModelChecker::check_recency(ModelAction *curr) {
 
 /**
  * Updates the mo_graph with the constraints imposed from the current
- * read.  
+ * read.
  *
  * Basic idea is the following: Go through each other thread and find
  * the lastest action that happened before our read.  Two cases:
@@ -871,7 +874,7 @@ bool ModelChecker::r_modification_order(ModelAction *curr, const ModelAction *rf
  *  promises.  The basic problem is that actions that occur after the
  *  read curr could not property add items to the modification order
  *  for our read.
- *  
+ *
  *  So for each thread, we find the earliest item that happens after
  *  the read curr.  This is the item we have to fix up with additional
  *  constraints.  If that action is write, we add a MO edge between
@@ -1007,7 +1010,7 @@ bool ModelChecker::w_modification_order(ModelAction *curr)
                                 */
                                if (thin_air_constraint_may_allow(curr, act)) {
                                        if (isfeasible() ||
-                                                       (curr->is_rmw() && act->is_rmw() && curr->get_reads_from()==act->get_reads_from() && isfeasibleotherthanRMW())) {
+                                                       (curr->is_rmw() && act->is_rmw() && curr->get_reads_from() == act->get_reads_from() && isfeasibleotherthanRMW())) {
                                                struct PendingFutureValue pfv = {curr->get_value(),curr->get_seq_number()+params.maxfuturedelay,act};
                                                futurevalues->push_back(pfv);
                                        }
@@ -1031,7 +1034,7 @@ bool ModelChecker::thin_air_constraint_may_allow(const ModelAction * writer, con
                return true;
 
        for (const ModelAction *search = writer->get_reads_from(); search != NULL; search = search->get_reads_from()) {
-               if (search==reader)
+               if (search == reader)
                        return false;
                if (search->get_tid() == reader->get_tid() &&
                                search->happens_before(reader))
@@ -1124,8 +1127,6 @@ bool ModelChecker::release_seq_head(const ModelAction *rf, rel_heads_list_t *rel
 
                for (rit = list->rbegin(); rit != list->rend(); rit++) {
                        const ModelAction *act = *rit;
-                       if (!act->is_write())
-                               continue;
                        /* Reach synchronization -> this thread is complete */
                        if (act->happens_before(release))
                                break;
@@ -1134,6 +1135,10 @@ bool ModelChecker::release_seq_head(const ModelAction *rf, rel_heads_list_t *rel
                                continue;
                        }
 
+                       /* Only writes can break release sequences */
+                       if (!act->is_write())
+                               continue;
+
                        /* Check modification order */
                        if (mo_graph->checkReachable(rf, act)) {
                                /* rf --mo--> act */
@@ -1178,10 +1183,7 @@ void ModelChecker::get_release_seq_heads(ModelAction *act, rel_heads_list_t *rel
        complete = release_seq_head(rf, release_heads);
        if (!complete) {
                /* add act to 'lazy checking' list */
-               action_list_t *list;
-               list = lazy_sync_with_release->get_safe_ptr(act->get_location());
-               list->push_back(act);
-               (*lazy_sync_size)++;
+               pending_acq_rel_seq->push_back(act);
        }
 }
 
@@ -1192,7 +1194,7 @@ void ModelChecker::get_release_seq_heads(ModelAction *act, rel_heads_list_t *rel
  * modification order information is present at the time an action occurs.
  *
  * @param location The location/object that should be checked for release
- * sequence resolutions
+ * 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
@@ -1200,15 +1202,17 @@ 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)
 {
-       action_list_t *list;
-       list = lazy_sync_with_release->getptr(location);
-       if (!list)
-               return false;
-
        bool updated = false;
-       action_list_t::iterator it = list->begin();
-       while (it != list->end()) {
+       std::vector<ModelAction *>::iterator it = pending_acq_rel_seq->begin();
+       while (it != pending_acq_rel_seq->end()) {
                ModelAction *act = *it;
+
+               /* Only resolve sequences on the given location, if provided */
+               if (location && act->get_location() != location) {
+                       it++;
+                       continue;
+               }
+
                const ModelAction *rf = act->get_reads_from();
                rel_heads_list_t release_heads;
                bool complete;
@@ -1226,7 +1230,7 @@ bool ModelChecker::resolve_release_sequences(void *location, work_queue_t *work_
 
                        /* propagate synchronization to later actions */
                        action_list_t::reverse_iterator it = action_trace->rbegin();
-                       while ((*it) != act) {
+                       for (; (*it) != act; it++) {
                                ModelAction *propagate = *it;
                                if (act->happens_before(propagate)) {
                                        propagate->synchronize_with(act);
@@ -1235,10 +1239,9 @@ bool ModelChecker::resolve_release_sequences(void *location, work_queue_t *work_
                                }
                        }
                }
-               if (complete) {
-                       it = list->erase(it);
-                       (*lazy_sync_size)--;
-               } else
+               if (complete)
+                       it = pending_acq_rel_seq->erase(it);
+               else
                        it++;
        }
 
@@ -1457,7 +1460,7 @@ void ModelChecker::build_reads_from_past(ModelAction *curr)
                                continue;
 
                        /* Don't consider more than one seq_cst write if we are a seq_cst read. */
-                       if (!curr->is_seqcst()|| (!act->is_seqcst() && (last_seq_cst==NULL||!act->happens_before(last_seq_cst))) || act == last_seq_cst) {
+                       if (!curr->is_seqcst() || (!act->is_seqcst() && (last_seq_cst == NULL || !act->happens_before(last_seq_cst))) || act == last_seq_cst) {
                                DEBUG("Adding action to may_read_from:\n");
                                if (DBG_ENABLED()) {
                                        act->print();
@@ -1534,6 +1537,11 @@ void ModelChecker::add_thread(Thread *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);