Modified the implementation of usleep and make ModelExecution process "THREAD SLEEP...
[c11tester.git] / execution.cc
index 40b83e05f9b7c2c6eecdaa7686a6846dceaedd40..870dcb1a9d06bd25614e4d872f6e6c9ae80045a4 100644 (file)
@@ -6,7 +6,6 @@
 #include "model.h"
 #include "execution.h"
 #include "action.h"
-#include "nodestack.h"
 #include "schedule.h"
 #include "common.h"
 #include "clockvector.h"
@@ -14,7 +13,9 @@
 #include "datarace.h"
 #include "threads-model.h"
 #include "bugmessage.h"
+#include "history.h"
 #include "fuzzer.h"
+#include "newfuzzer.h"
 
 #define INITIAL_THREAD_ID       0
 
@@ -48,7 +49,7 @@ struct model_snapshot_members {
 };
 
 /** @brief Constructor */
-ModelExecution::ModelExecution(ModelChecker *m, Scheduler *scheduler, NodeStack *node_stack) :
+ModelExecution::ModelExecution(ModelChecker *m, Scheduler *scheduler) :
        model(m),
        params(NULL),
        scheduler(scheduler),
@@ -62,16 +63,18 @@ ModelExecution::ModelExecution(ModelChecker *m, Scheduler *scheduler, NodeStack
        mutex_map(),
        thrd_last_action(1),
        thrd_last_fence_release(),
-       node_stack(node_stack),
        priv(new struct model_snapshot_members ()),
-                        mo_graph(new CycleGraph()),
-       fuzzer(new Fuzzer())
+       mo_graph(new CycleGraph()),
+       fuzzer(new NewFuzzer()),
+       thrd_func_list(),
+       thrd_func_act_lists(),
+       isfinished(false)
 {
        /* Initialize a model-checker thread, for special ModelActions */
        model_thread = new Thread(get_next_id());
        add_thread(model_thread);
        scheduler->register_engine(this);
-       node_stack->register_engine(this);
+       fuzzer->register_engine(m->get_history(), this);
 }
 
 /** @brief Destructor */
@@ -89,7 +92,7 @@ int ModelExecution::get_execution_number() const
        return model->get_execution_number();
 }
 
-static action_list_t * get_safe_ptr_action(HashTable<const void *, action_list_t *, uintptr_t, 4> * hash, void * ptr)
+static action_list_t * get_safe_ptr_action(HashTable<const void *, action_list_t *, uintptr_t, 2> * hash, void * ptr)
 {
        action_list_t *tmp = hash->get(ptr);
        if (tmp == NULL) {
@@ -99,7 +102,7 @@ static action_list_t * get_safe_ptr_action(HashTable<const void *, action_list_t
        return tmp;
 }
 
-static SnapVector<action_list_t> * get_safe_ptr_vect_action(HashTable<void *, SnapVector<action_list_t> *, uintptr_t, 4> * hash, void * ptr)
+static SnapVector<action_list_t> * get_safe_ptr_vect_action(HashTable<const void *, SnapVector<action_list_t> *, uintptr_t, 2> * hash, void * ptr)
 {
        SnapVector<action_list_t> *tmp = hash->get(ptr);
        if (tmp == NULL) {
@@ -127,6 +130,12 @@ modelclock_t ModelExecution::get_next_seq_num()
        return ++priv->used_sequence_numbers;
 }
 
+/** Restore the last used sequence number when actions of a thread are postponed by Fuzzer */
+void ModelExecution::restore_last_seq_num()
+{
+       priv->used_sequence_numbers--;
+}
+
 /**
  * @brief Should the current action wake up a given thread?
  *
@@ -152,6 +161,11 @@ bool ModelExecution::should_wake_up(const ModelAction *curr, const Thread *threa
                if (fence_release && *(get_last_action(thread->get_id())) < *fence_release)
                        return true;
        }
+       if (asleep->is_sleep()) {
+               if (fuzzer->shouldWake(asleep))
+                       return true;
+       }
+
        return false;
 }
 
@@ -160,9 +174,12 @@ void ModelExecution::wake_up_sleeping_actions(ModelAction *curr)
        for (unsigned int i = 0;i < get_num_threads();i++) {
                Thread *thr = get_thread(int_to_id(i));
                if (scheduler->is_sleep_set(thr)) {
-                       if (should_wake_up(curr, thr))
+                       if (should_wake_up(curr, thr)) {
                                /* Remove this thread from sleep set */
                                scheduler->remove_sleep(thr);
+                               if (thr->get_pending()->is_sleep())
+                                       thr->set_pending(NULL);
+                       }
                }
        }
 }
@@ -253,6 +270,20 @@ bool ModelExecution::is_complete_execution() const
        return true;
 }
 
+ModelAction * ModelExecution::convertNonAtomicStore(void * location) {
+       uint64_t value = *((const uint64_t *) location);
+       modelclock_t storeclock;
+       thread_id_t storethread;
+       getStoreThreadAndClock(location, &storethread, &storeclock);
+       setAtomicStoreFlag(location);
+       ModelAction * act = new ModelAction(NONATOMIC_WRITE, memory_order_relaxed, location, value, get_thread(storethread));
+       act->set_seq_number(storeclock);
+       add_normal_write_to_lists(act);
+       add_write_to_lists(act);
+       w_modification_order(act);
+       model->get_history()->process_action(act, act->get_tid());
+       return act;
+}
 
 /**
  * Processes a read model action.
@@ -260,14 +291,21 @@ bool ModelExecution::is_complete_execution() const
  * @param rf_set is the set of model actions we can possibly read from
  * @return True if processing this read updates the mo_graph.
  */
-void ModelExecution::process_read(ModelAction *curr, SnapVector<ModelAction *> * rf_set)
+bool ModelExecution::process_read(ModelAction *curr, SnapVector<ModelAction *> * rf_set)
 {
        SnapVector<const ModelAction *> * priorset = new SnapVector<const ModelAction *>();
-       while(true) {
+       bool hasnonatomicstore = hasNonAtomicStore(curr->get_location());
+       if (hasnonatomicstore) {
+               ModelAction * nonatomicstore = convertNonAtomicStore(curr->get_location());
+               rf_set->push_back(nonatomicstore);
+       }
 
+       while(true) {
                int index = fuzzer->selectWrite(curr, rf_set);
-               ModelAction *rf = (*rf_set)[index];
+               if (index == -1)        // no feasible write exists
+                       return false;
 
+               ModelAction *rf = (*rf_set)[index];
 
                ASSERT(rf);
                bool canprune = false;
@@ -282,7 +320,7 @@ void ModelExecution::process_read(ModelAction *curr, SnapVector<ModelAction *> *
                                int tid = id_to_int(curr->get_tid());
                                (*obj_thrd_map.get(curr->get_location()))[tid].pop_back();
                        }
-                       return;
+                       return true;
                }
                priorset->clear();
                (*rf_set)[index] = rf_set->back();
@@ -326,8 +364,9 @@ bool ModelExecution::process_mutex(ModelAction *curr)
        }
        //otherwise fall into the lock case
        case ATOMIC_LOCK: {
-               if (curr->get_cv()->getClock(state->alloc_tid) <= state->alloc_clock)
-                       assert_bug("Lock access before initialization");
+               //TODO: FIND SOME BETTER WAY TO CHECK LOCK INITIALIZED OR NOT
+               //if (curr->get_cv()->getClock(state->alloc_tid) <= state->alloc_clock)
+               //      assert_bug("Lock access before initialization");
                state->locked = get_thread(curr);
                ModelAction *unlock = get_last_unlock(curr);
                //synchronize with the previous unlock statement
@@ -337,7 +376,27 @@ bool ModelExecution::process_mutex(ModelAction *curr)
                }
                break;
        }
-       case ATOMIC_WAIT:
+       case ATOMIC_WAIT: {
+               /* wake up the other threads */
+               for (unsigned int i = 0;i < get_num_threads();i++) {
+                       Thread *t = get_thread(int_to_id(i));
+                       Thread *curr_thrd = get_thread(curr);
+                       if (t->waiting_on() == curr_thrd && t->get_pending()->is_lock())
+                               scheduler->wake(t);
+               }
+
+               /* unlock the lock - after checking who was waiting on it */
+               state->locked = NULL;
+
+               if (fuzzer->shouldWait(curr)) {
+                       /* disable this thread */
+                       get_safe_ptr_action(&condvar_waiters_map, curr->get_location())->push_back(curr);
+                       scheduler->sleep(get_thread(curr));
+               }
+
+               break;
+       }
+       case ATOMIC_TIMEDWAIT:
        case ATOMIC_UNLOCK: {
                //TODO: FIX WAIT SITUATION...WAITS CAN SPURIOUSLY FAIL...TIMED WAITS SHOULD PROBABLY JUST BE THE SAME AS NORMAL WAITS...THINK ABOUT PROBABILITIES THOUGH....AS IN TIMED WAIT MUST FAIL TO GUARANTEE PROGRESS...NORMAL WAIT MAY FAIL...SO NEED NORMAL WAIT TO WORK CORRECTLY IN THE CASE IT SPURIOUSLY FAILS AND IN THE CASE IT DOESN'T...  TIMED WAITS MUST EVENMTUALLY RELEASE...
 
@@ -351,17 +410,13 @@ bool ModelExecution::process_mutex(ModelAction *curr)
 
                /* unlock the lock - after checking who was waiting on it */
                state->locked = NULL;
-
-               if (!curr->is_wait())
-                       break;/* The rest is only for ATOMIC_WAIT */
-
                break;
        }
        case ATOMIC_NOTIFY_ALL: {
                action_list_t *waiters = get_safe_ptr_action(&condvar_waiters_map, curr->get_location());
                //activate all the waiting threads
-               for (action_list_t::iterator rit = waiters->begin();rit != waiters->end();rit++) {
-                       scheduler->wake(get_thread(*rit));
+               for (sllnode<ModelAction *> * rit = waiters->begin();rit != NULL;rit=rit->getNext()) {
+                       scheduler->wake(get_thread(rit->getVal()));
                }
                waiters->clear();
                break;
@@ -388,10 +443,7 @@ bool ModelExecution::process_mutex(ModelAction *curr)
  */
 void ModelExecution::process_write(ModelAction *curr)
 {
-
        w_modification_order(curr);
-
-
        get_thread(curr)->set_return_value(VALUE_NONE);
 }
 
@@ -413,10 +465,10 @@ bool ModelExecution::process_fence(ModelAction *curr)
        bool updated = false;
        if (curr->is_acquire()) {
                action_list_t *list = &action_trace;
-               action_list_t::reverse_iterator rit;
+               sllnode<ModelAction *> * rit;
                /* Find X : is_read(X) && X --sb-> curr */
-               for (rit = list->rbegin();rit != list->rend();rit++) {
-                       ModelAction *act = *rit;
+               for (rit = list->end();rit != NULL;rit=rit->getPrev()) {
+                       ModelAction *act = rit->getVal();
                        if (act == curr)
                                continue;
                        if (act->get_tid() != curr->get_tid())
@@ -434,8 +486,8 @@ bool ModelExecution::process_fence(ModelAction *curr)
                                continue;
 
                        /* Establish hypothetical release sequences */
-                       ClockVector *cv = get_hb_from_write(act);
-                       if (curr->get_cv()->merge(cv))
+                       ClockVector *cv = get_hb_from_write(act->get_reads_from());
+                       if (cv != NULL && curr->get_cv()->merge(cv))
                                updated = true;
                }
        }
@@ -453,10 +505,8 @@ bool ModelExecution::process_fence(ModelAction *curr)
  * @param curr The current action
  * @return True if synchronization was updated or a thread completed
  */
-bool ModelExecution::process_thread_action(ModelAction *curr)
+void ModelExecution::process_thread_action(ModelAction *curr)
 {
-       bool updated = false;
-
        switch (curr->get_type()) {
        case THREAD_CREATE: {
                thrd_t *thrd = (thrd_t *)curr->get_location();
@@ -486,19 +536,25 @@ bool ModelExecution::process_thread_action(ModelAction *curr)
                Thread *blocking = curr->get_thread_operand();
                ModelAction *act = get_last_action(blocking->get_id());
                synchronize(act, curr);
-               updated = true; /* trigger rel-seq checks */
                break;
        }
        case PTHREAD_JOIN: {
                Thread *blocking = curr->get_thread_operand();
                ModelAction *act = get_last_action(blocking->get_id());
                synchronize(act, curr);
-               updated = true; /* trigger rel-seq checks */
                break;  // WL: to be add (modified)
        }
 
+       case THREADONLY_FINISH:
        case THREAD_FINISH: {
                Thread *th = get_thread(curr);
+               if (curr->get_type() == THREAD_FINISH &&
+                               th == model->getInitThread()) {
+                       th->complete();
+                       setFinished();
+                       break;
+               }
+
                /* Wake up any joining threads */
                for (unsigned int i = 0;i < get_num_threads();i++) {
                        Thread *waiting = get_thread(int_to_id(i));
@@ -507,23 +563,26 @@ bool ModelExecution::process_thread_action(ModelAction *curr)
                                scheduler->wake(waiting);
                }
                th->complete();
-               updated = true; /* trigger rel-seq checks */
                break;
        }
        case THREAD_START: {
                break;
        }
+       case THREAD_SLEEP: {
+               Thread *th = get_thread(curr);
+               th->set_pending(curr);
+               scheduler->add_sleep(th);
+               break;
+       }
        default:
                break;
        }
-
-       return updated;
 }
 
 /**
  * Initialize the current action by performing one or more of the following
- * actions, as appropriate: merging RMWR and RMWC/RMW actions, stepping forward
- * in the NodeStack, manipulating backtracking sets, allocating and
+ * actions, as appropriate: merging RMWR and RMWC/RMW actions,
+ * manipulating backtracking sets, allocating and
  * initializing clock vectors, and computing the promises to fulfill.
  *
  * @param curr The current action, as passed from the user context; may be
@@ -543,7 +602,6 @@ bool ModelExecution::initialize_curr_action(ModelAction **curr)
                ModelAction *newcurr = *curr;
 
                newcurr->set_seq_number(get_next_seq_num());
-               node_stack->add_action(newcurr);
                /* Always compute new clock vector */
                newcurr->create_cv(get_parent_action(newcurr->get_tid()));
 
@@ -623,6 +681,9 @@ bool ModelExecution::check_action_enabled(ModelAction *curr) {
                if (!blocking->is_complete()) {
                        return false;
                }
+       } else if (curr->is_sleep()) {
+               if (!fuzzer->shouldSleep(curr))
+                       return false;
        }
 
        return true;
@@ -649,23 +710,35 @@ ModelAction * ModelExecution::check_current_action(ModelAction *curr)
 
        wake_up_sleeping_actions(curr);
 
-       /* Add the action to lists before any other model-checking tasks */
-       if (!second_part_of_rmw && curr->get_type() != NOOP)
-               add_action_to_lists(curr);
+       /* Add uninitialized actions to lists */
+       if (!second_part_of_rmw)
+               add_uninit_action_to_lists(curr);
 
        SnapVector<ModelAction *> * rf_set = NULL;
        /* Build may_read_from set for newly-created actions */
        if (newly_explored && curr->is_read())
                rf_set = build_may_read_from(curr);
 
-       process_thread_action(curr);
-
        if (curr->is_read() && !second_part_of_rmw) {
                process_read(curr, rf_set);
                delete rf_set;
-       } else {
+
+/*             bool success = process_read(curr, rf_set);
+               delete rf_set;
+               if (!success)
+                       return curr;    // Do not add action to lists
+*/
+       } else
                ASSERT(rf_set == NULL);
-       }
+
+       /* Add the action to lists */
+       if (!second_part_of_rmw)
+               add_action_to_lists(curr);
+
+       if (curr->is_write())
+               add_write_to_lists(curr);
+
+       process_thread_action(curr);
 
        if (curr->is_write())
                process_write(curr);
@@ -774,9 +847,9 @@ bool ModelExecution::r_modification_order(ModelAction *curr, const ModelAction *
 
                /* Iterate over actions in thread, starting from most recent */
                action_list_t *list = &(*thrd_lists)[tid];
-               action_list_t::reverse_iterator rit;
-               for (rit = list->rbegin();rit != list->rend();rit++) {
-                       ModelAction *act = *rit;
+               sllnode<ModelAction *> * rit;
+               for (rit = list->end();rit != NULL;rit=rit->getPrev()) {
+                       ModelAction *act = rit->getVal();
 
                        /* Skip curr */
                        if (act == curr)
@@ -823,7 +896,7 @@ bool ModelExecution::r_modification_order(ModelAction *curr, const ModelAction *
                        if (act->happens_before(curr)) {
                                if (i==0) {
                                        if (last_sc_fence_local == NULL ||
-                                                       (*last_sc_fence_local < *prev_same_thread)) {
+                                                       (*last_sc_fence_local < *act)) {
                                                prev_same_thread = act;
                                        }
                                }
@@ -881,13 +954,17 @@ void ModelExecution::w_modification_order(ModelAction *curr)
        unsigned int i;
        ASSERT(curr->is_write());
 
+       SnapList<ModelAction *> edgeset;
+
        if (curr->is_seqcst()) {
                /* We have to at least see the last sequentially consistent write,
                         so we are initialized. */
                ModelAction *last_seq_cst = get_last_seq_cst_write(curr);
                if (last_seq_cst != NULL) {
-                       mo_graph->addEdge(last_seq_cst, curr);
+                       edgeset.push_back(last_seq_cst);
                }
+               //update map for next query
+               obj_last_sc_map.put(curr->get_location(), curr);
        }
 
        /* Last SC fence in the current thread */
@@ -902,10 +979,9 @@ void ModelExecution::w_modification_order(ModelAction *curr)
 
                /* Iterate over actions in thread, starting from most recent */
                action_list_t *list = &(*thrd_lists)[i];
-               action_list_t::reverse_iterator rit;
-               bool force_edge = false;
-               for (rit = list->rbegin();rit != list->rend();rit++) {
-                       ModelAction *act = *rit;
+               sllnode<ModelAction*>* rit;
+               for (rit = list->end();rit != NULL;rit=rit->getPrev()) {
+                       ModelAction *act = rit->getVal();
                        if (act == curr) {
                                /*
                                 * 1) If RMW and it actually read from something, then we
@@ -918,7 +994,6 @@ void ModelExecution::w_modification_order(ModelAction *curr)
                                 * 3) If normal write, we need to look at earlier actions, so
                                 * continue processing list.
                                 */
-                               force_edge = true;
                                if (curr->is_rmw()) {
                                        if (curr->get_reads_from() != NULL)
                                                break;
@@ -931,7 +1006,7 @@ void ModelExecution::w_modification_order(ModelAction *curr)
                        /* C++, Section 29.3 statement 7 */
                        if (last_sc_fence_thread_before && act->is_write() &&
                                        *act < *last_sc_fence_thread_before) {
-                               mo_graph->addEdge(act, curr, force_edge);
+                               edgeset.push_back(act);
                                break;
                        }
 
@@ -947,30 +1022,17 @@ void ModelExecution::w_modification_order(ModelAction *curr)
                                 *   readfrom(act) --mo--> act
                                 */
                                if (act->is_write())
-                                       mo_graph->addEdge(act, curr, force_edge);
+                                       edgeset.push_back(act);
                                else if (act->is_read()) {
                                        //if previous read accessed a null, just keep going
-                                       mo_graph->addEdge(act->get_reads_from(), curr, force_edge);
+                                       edgeset.push_back(act->get_reads_from());
                                }
                                break;
-                       } else if (act->is_read() && !act->could_synchronize_with(curr) &&
-                                                                !act->same_thread(curr)) {
-                               /* We have an action that:
-                                  (1) did not happen before us
-                                  (2) is a read and we are a write
-                                  (3) cannot synchronize with us
-                                  (4) is in a different thread
-                                  =>
-                                  that read could potentially read from our write.  Note that
-                                  these checks are overly conservative at this point, we'll
-                                  do more checks before actually removing the
-                                  pendingfuturevalue.
-
-                                */
-
                        }
                }
        }
+       mo_graph->addEdges(&edgeset, curr);
+
 }
 
 /**
@@ -991,9 +1053,9 @@ bool ModelExecution::mo_may_allow(const ModelAction *writer, const ModelAction *
 
                /* 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;
+               sllnode<ModelAction *>* rit;
+               for (rit = list->end();rit != NULL;rit=rit->getPrev()) {
+                       ModelAction *act = rit->getVal();
 
                        /* Don't disallow due to act == reader */
                        if (!reader->happens_before(act) || reader == act)
@@ -1019,20 +1081,20 @@ bool ModelExecution::mo_may_allow(const ModelAction *writer, const ModelAction *
  */
 
 ClockVector * ModelExecution::get_hb_from_write(ModelAction *rf) const {
-       SnapVector<const ModelAction *> * processset = NULL;
+       SnapVector<ModelAction *> * processset = NULL;
        for ( ;rf != NULL;rf = rf->get_reads_from()) {
                ASSERT(rf->is_write());
                if (!rf->is_rmw() || (rf->is_acquire() && rf->is_release()) || rf->get_rfcv() != NULL)
                        break;
                if (processset == NULL)
-                       processset = new SnapVector<const ModelAction *>();
+                       processset = new SnapVector<ModelAction *>();
                processset->push_back(rf);
        }
 
-       int i = (processset == NULL) ? 1 : processset->size();
+       int i = (processset == NULL) ? 0 : processset->size();
 
        ClockVector * vec = NULL;
-       for(;i > 0 ;i--) {
+       while(true) {
                if (rf->get_rfcv() != NULL) {
                        vec = rf->get_rfcv();
                } else if (rf->is_acquire() && rf->is_release()) {
@@ -1053,6 +1115,11 @@ ClockVector * ModelExecution::get_hb_from_write(ModelAction *rf) const {
                        }
                        rf->set_rfcv(vec);
                }
+               i--;
+               if (i >= 0) {
+                       rf = (*processset)[i];
+               } else
+                       break;
        }
        if (processset != NULL)
                delete processset;
@@ -1060,13 +1127,15 @@ ClockVector * ModelExecution::get_hb_from_write(ModelAction *rf) const {
 }
 
 /**
- * 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.
+ * Performs various bookkeeping operations for the current ModelAction when it is
+ * the first atomic action occurred at its memory location.
  *
- * @param act is the ModelAction to add.
+ * For instance, adds uninitialized 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 process.
  */
-void ModelExecution::add_action_to_lists(ModelAction *act)
+void ModelExecution::add_uninit_action_to_lists(ModelAction *act)
 {
        int tid = id_to_int(act->get_tid());
        ModelAction *uninit = NULL;
@@ -1076,26 +1145,72 @@ void ModelExecution::add_action_to_lists(ModelAction *act)
                uninit = get_uninitialized_action(act);
                uninit_id = id_to_int(uninit->get_tid());
                list->push_front(uninit);
+               SnapVector<action_list_t> *vec = get_safe_ptr_vect_action(&obj_wr_thrd_map, act->get_location());
+               if ((int)vec->size() <= uninit_id) {
+                       int oldsize = (int) vec->size();
+                       vec->resize(uninit_id + 1);
+                       for(int i = oldsize; i < uninit_id + 1; i++) {
+                               new (&(*vec)[i]) action_list_t();
+                       }
+               }
+               (*vec)[uninit_id].push_front(uninit);
        }
-       list->push_back(act);
 
-       action_trace.push_back(act);
+       // Update action trace, a total order of all actions
        if (uninit)
                action_trace.push_front(uninit);
 
+       // Update obj_thrd_map, a per location, per thread, order of actions
        SnapVector<action_list_t> *vec = get_safe_ptr_vect_action(&obj_thrd_map, act->get_location());
-       if (tid >= (int)vec->size())
+       if ((int)vec->size() <= tid) {
+               uint oldsize = vec->size();
                vec->resize(priv->next_thread_id);
-       (*vec)[tid].push_back(act);
+               for(uint i = oldsize; i < priv->next_thread_id; i++)
+                       new (&(*vec)[i]) action_list_t();
+       }
        if (uninit)
                (*vec)[uninit_id].push_front(uninit);
 
+       // Update thrd_last_action, the last action taken by each thrad
        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;
+}
+
+
+/**
+ * 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 ModelExecution::add_action_to_lists(ModelAction *act)
+{
+       int tid = id_to_int(act->get_tid());
+       action_list_t *list = get_safe_ptr_action(&obj_map, act->get_location());
+       list->push_back(act);
+
+       // Update action trace, a total order of all actions
+       action_trace.push_back(act);
 
+       // Update obj_thrd_map, a per location, per thread, order of actions
+       SnapVector<action_list_t> *vec = get_safe_ptr_vect_action(&obj_thrd_map, act->get_location());
+       if ((int)vec->size() <= tid) {
+               uint oldsize = vec->size();
+               vec->resize(priv->next_thread_id);
+               for(uint i = oldsize; i < priv->next_thread_id; i++)
+                       new (&(*vec)[i]) action_list_t();
+       }
+       (*vec)[tid].push_back(act);
+
+       // Update thrd_last_action, the last action taken by each thrad
+       if ((int)thrd_last_action.size() <= tid)
+               thrd_last_action.resize(get_num_threads());
+       thrd_last_action[tid] = act;
+
+       // Update thrd_last_fence_release, the last release fence taken by each thread
        if (act->is_fence() && act->is_release()) {
                if ((int)thrd_last_fence_release.size() <= tid)
                        thrd_last_fence_release.resize(get_num_threads());
@@ -1107,12 +1222,94 @@ void ModelExecution::add_action_to_lists(ModelAction *act)
                get_safe_ptr_action(&obj_map, mutex_loc)->push_back(act);
 
                SnapVector<action_list_t> *vec = get_safe_ptr_vect_action(&obj_thrd_map, mutex_loc);
-               if (tid >= (int)vec->size())
+               if ((int)vec->size() <= tid) {
+                       uint oldsize = vec->size();
                        vec->resize(priv->next_thread_id);
+                       for(uint i = oldsize; i < priv->next_thread_id; i++)
+                               new (&(*vec)[i]) action_list_t();
+               }
                (*vec)[tid].push_back(act);
        }
 }
 
+void insertIntoActionList(action_list_t *list, ModelAction *act) {
+       sllnode<ModelAction*> * rit = list->end();
+       modelclock_t next_seq = act->get_seq_number();
+       if (rit == NULL || (rit->getVal()->get_seq_number() == next_seq))
+               list->push_back(act);
+       else {
+               for(;rit != NULL;rit=rit->getPrev()) {
+                       if (rit->getVal()->get_seq_number() == next_seq) {
+                               list->insertAfter(rit, act);
+                               break;
+                       }
+               }
+       }
+}
+
+void insertIntoActionListAndSetCV(action_list_t *list, ModelAction *act) {
+       sllnode<ModelAction*> * rit = list->end();
+       modelclock_t next_seq = act->get_seq_number();
+       if (rit == NULL) {
+               act->create_cv(NULL);
+       } else if (rit->getVal()->get_seq_number() == next_seq) {
+               act->create_cv(rit->getVal());
+               list->push_back(act);
+       } else {
+               for(;rit != NULL;rit=rit->getPrev()) {
+                       if (rit->getVal()->get_seq_number() == next_seq) {
+                               act->create_cv(rit->getVal());
+                               list->insertAfter(rit, act);
+                               break;
+                       }
+               }
+       }
+}
+
+/**
+ * Performs various bookkeeping operations for a normal write.  The
+ * complication is that we are typically inserting a normal write
+ * lazily, so we need to insert it into the middle of lists.
+ *
+ * @param act is the ModelAction to add.
+ */
+
+void ModelExecution::add_normal_write_to_lists(ModelAction *act)
+{
+       int tid = id_to_int(act->get_tid());
+       insertIntoActionListAndSetCV(&action_trace, act);
+
+       action_list_t *list = get_safe_ptr_action(&obj_map, act->get_location());
+       insertIntoActionList(list, act);
+
+       // Update obj_thrd_map, a per location, per thread, order of actions
+       SnapVector<action_list_t> *vec = get_safe_ptr_vect_action(&obj_thrd_map, act->get_location());
+       if (tid >= (int)vec->size()) {
+               uint oldsize =vec->size();
+               vec->resize(priv->next_thread_id);
+               for(uint i=oldsize;i<priv->next_thread_id;i++)
+                       new (&(*vec)[i]) action_list_t();
+       }
+       insertIntoActionList(&(*vec)[tid],act);
+
+       // Update thrd_last_action, the last action taken by each thrad
+       if (thrd_last_action[tid]->get_seq_number() == act->get_seq_number())
+               thrd_last_action[tid] = act;
+}
+
+
+void ModelExecution::add_write_to_lists(ModelAction *write) {
+       SnapVector<action_list_t> *vec = get_safe_ptr_vect_action(&obj_wr_thrd_map, write->get_location());
+       int tid = id_to_int(write->get_tid());
+       if (tid >= (int)vec->size()) {
+               uint oldsize =vec->size();
+               vec->resize(priv->next_thread_id);
+               for(uint i=oldsize;i<priv->next_thread_id;i++)
+                       new (&(*vec)[i]) action_list_t();
+       }
+       (*vec)[tid].push_back(write);
+}
+
 /**
  * @brief Get the last action performed by a particular Thread
  * @param tid The thread ID of the Thread in question
@@ -1152,16 +1349,7 @@ 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 = 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++)
-               ;
-       rit++;  /* Skip past curr */
-       for ( ;rit != list->rend();rit++)
-               if ((*rit)->is_write() && (*rit)->is_seqcst())
-                       return *rit;
-       return NULL;
+       return obj_last_sc_map.get(location);
 }
 
 /**
@@ -1180,20 +1368,22 @@ ModelAction * ModelExecution::get_last_seq_cst_fence(thread_id_t tid, const Mode
        if (!list)
                return NULL;
 
-       action_list_t::reverse_iterator rit = list->rbegin();
+       sllnode<ModelAction*>* rit = list->end();
 
        if (before_fence) {
-               for (;rit != list->rend();rit++)
-                       if (*rit == before_fence)
+               for (;rit != NULL;rit=rit->getPrev())
+                       if (rit->getVal() == before_fence)
                                break;
 
-               ASSERT(*rit == before_fence);
-               rit++;
+               ASSERT(rit->getVal() == before_fence);
+               rit=rit->getPrev();
        }
 
-       for (;rit != list->rend();rit++)
-               if ((*rit)->is_fence() && (tid == (*rit)->get_tid()) && (*rit)->is_seqcst())
-                       return *rit;
+       for (;rit != NULL;rit=rit->getPrev()) {
+               ModelAction *act = rit->getVal();
+               if (act->is_fence() && (tid == act->get_tid()) && act->is_seqcst())
+                       return act;
+       }
        return NULL;
 }
 
@@ -1211,10 +1401,10 @@ ModelAction * ModelExecution::get_last_unlock(ModelAction *curr) const
 
        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++)
-               if ((*rit)->is_unlock() || (*rit)->is_wait())
-                       return *rit;
+       sllnode<ModelAction*>* rit;
+       for (rit = list->end();rit != NULL;rit=rit->getPrev())
+               if (rit->getVal()->is_unlock() || rit->getVal()->is_wait())
+                       return rit->getVal();
        return NULL;
 }
 
@@ -1262,7 +1452,7 @@ bool valequals(uint64_t val1, uint64_t val2, int size) {
  */
 SnapVector<ModelAction *> *  ModelExecution::build_may_read_from(ModelAction *curr)
 {
-       SnapVector<action_list_t> *thrd_lists = obj_thrd_map.get(curr->get_location());
+       SnapVector<action_list_t> *thrd_lists = obj_wr_thrd_map.get(curr->get_location());
        unsigned int i;
        ASSERT(curr->is_read());
 
@@ -1277,21 +1467,9 @@ SnapVector<ModelAction *> *  ModelExecution::build_may_read_from(ModelAction *cu
        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()) {
-                               if (act != curr && act->is_read() && act->happens_before(curr)) {
-                                       ModelAction *tmp = act->get_reads_from();
-                                       if (((unsigned int) id_to_int(tmp->get_tid()))==i)
-                                               act = tmp;
-                                       else
-                                               break;
-                               } else
-                                       continue;
-                       }
+               sllnode<ModelAction *> * rit;
+               for (rit = list->end();rit != NULL;rit=rit->getPrev()) {
+                       ModelAction *act = rit->getVal();
 
                        if (act == curr)
                                continue;
@@ -1338,26 +1516,25 @@ SnapVector<ModelAction *> *  ModelExecution::build_may_read_from(ModelAction *cu
 /**
  * @brief Get an action representing an uninitialized atomic
  *
- * This function may create a new one or try to retrieve one from the NodeStack
+ * This function may create a new one.
  *
  * @param curr The current action, which prompts the creation of an UNINIT action
  * @return A pointer to the UNINIT ModelAction
  */
-ModelAction * ModelExecution::get_uninitialized_action(const ModelAction *curr) const
+ModelAction * ModelExecution::get_uninitialized_action(ModelAction *curr) const
 {
-       Node *node = curr->get_node();
-       ModelAction *act = node->get_uninit_action();
+       ModelAction *act = curr->get_uninit_action();
        if (!act) {
                act = new ModelAction(ATOMIC_UNINIT, std::memory_order_relaxed, curr->get_location(), params->uninitvalue, model_thread);
-               node->set_uninit_action(act);
+               curr->set_uninit_action(act);
        }
        act->create_cv(NULL);
        return act;
 }
 
-static void print_list(const action_list_t *list)
+static void print_list(action_list_t *list)
 {
-       action_list_t::const_iterator it;
+       sllnode<ModelAction*> *it;
 
        model_print("------------------------------------------------------------------------------------\n");
        model_print("#    t    Action type     MO       Location         Value               Rf  CV\n");
@@ -1365,18 +1542,18 @@ static void print_list(const action_list_t *list)
 
        unsigned int hash = 0;
 
-       for (it = list->begin();it != list->end();it++) {
-               const ModelAction *act = *it;
+       for (it = list->begin();it != NULL;it=it->getNext()) {
+               const ModelAction *act = it->getVal();
                if (act->get_seq_number() > 0)
                        act->print();
-               hash = hash^(hash<<3)^((*it)->hash());
+               hash = hash^(hash<<3)^(it->getVal()->hash());
        }
        model_print("HASH %u\n", hash);
        model_print("------------------------------------------------------------------------------------\n");
 }
 
 #if SUPPORT_MOD_ORDER_DUMP
-void ModelExecution::dumpGraph(char *filename) const
+void ModelExecution::dumpGraph(char *filename)
 {
        char buffer[200];
        sprintf(buffer, "%s.dot", filename);
@@ -1385,8 +1562,8 @@ 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::const_iterator it = action_trace.begin();it != action_trace.end();it++) {
-               ModelAction *act = *it;
+       for (sllnode<ModelAction*>* it = action_trace.begin();it != NULL;it=it->getNext()) {
+               ModelAction *act = it->getVal();
                if (act->is_read()) {
                        mo_graph->dot_print_node(file, act);
                        mo_graph->dot_print_edge(file,
@@ -1410,7 +1587,7 @@ void ModelExecution::dumpGraph(char *filename) const
 #endif
 
 /** @brief Prints an execution trace summary. */
-void ModelExecution::print_summary() const
+void ModelExecution::print_summary()
 {
 #if SUPPORT_MOD_ORDER_DUMP
        char buffername[100];
@@ -1523,7 +1700,7 @@ bool ModelExecution::is_enabled(thread_id_t tid) const
 Thread * ModelExecution::action_select_next_thread(const ModelAction *curr) const
 {
        /* Do not split atomic RMW */
-       if (curr->is_rmwr())
+       if (curr->is_rmwr() && !paused_by_fuzzer(curr))
                return get_thread(curr);
        /* Follow CREATE with the created thread */
        /* which is not needed, because model.cc takes care of this */
@@ -1535,6 +1712,15 @@ Thread * ModelExecution::action_select_next_thread(const ModelAction *curr) cons
        return NULL;
 }
 
+/** @param act A read atomic action */
+bool ModelExecution::paused_by_fuzzer(const ModelAction * act) const
+{
+       ASSERT(act->is_read());
+
+       // Actions paused by fuzzer have their sequence number reset to 0
+       return act->get_seq_number() == 0;
+}
+
 /**
  * Takes the next step in the execution, if possible.
  * @param curr The current step to take
@@ -1550,6 +1736,9 @@ Thread * ModelExecution::take_step(ModelAction *curr)
        curr = check_current_action(curr);
        ASSERT(curr);
 
+       /* Process this action in ModelHistory for records */
+       model->get_history()->process_action( curr, curr->get_tid() );
+
        if (curr_thrd->is_blocked() || curr_thrd->is_complete())
                scheduler->remove_thread(curr_thrd);