rmw example works
[model-checker.git] / model.cc
index 31809918361c185cedc7d1ac791044f01bd23bad..e18fda15248399cda859339296447ca2b35bd9f5 100644 (file)
--- a/model.cc
+++ b/model.cc
@@ -118,7 +118,6 @@ Thread * ModelChecker::schedule_next_thread()
  */
 thread_id_t ModelChecker::get_next_replay_thread()
 {
-       ModelAction *next;
        thread_id_t tid;
 
        /* Have we completed exploring the preselected path? */
@@ -126,7 +125,7 @@ thread_id_t ModelChecker::get_next_replay_thread()
                return THREAD_ID_T_NONE;
 
        /* Else, we are trying to replay an execution */
-       next = node_stack->get_next()->get_action();
+       ModelAction * next = node_stack->get_next()->get_action();
 
        if (next == diverge) {
                Node *nextnode = next->get_node();
@@ -162,7 +161,10 @@ bool ModelChecker::next_execution()
        DBG();
 
        num_executions++;
-       print_summary();
+
+       if (isfeasible() || DBG_ENABLED())
+               print_summary();
+
        if ((diverge = model->get_next_backtrack()) == NULL)
                return false;
 
@@ -232,6 +234,11 @@ void ModelChecker::set_backtracking(ModelAction *act)
        }
 }
 
+/**
+ * Returns last backtracking point. The model checker will explore a different
+ * path for this point in the next execution.
+ * @return The ModelAction at which the next execution should diverge.
+ */
 ModelAction * ModelChecker::get_next_backtrack()
 {
        ModelAction *next = next_backtrack;
@@ -242,27 +249,37 @@ ModelAction * ModelChecker::get_next_backtrack()
 void ModelChecker::check_current_action(void)
 {
        ModelAction *curr = this->current_action;
-       ModelAction *tmp;
-       current_action = NULL;
+       bool already_added = false;
+       this->current_action = NULL;
        if (!curr) {
                DEBUG("trying to push NULL action...\n");
                return;
        }
 
-       tmp = node_stack->explore_action(curr);
-       if (tmp) {
-               /* Discard duplicate ModelAction; use action from NodeStack */
+       if (curr->is_rmwc()||curr->is_rmw()) {
+               ModelAction *tmp=process_rmw(curr);
+               already_added = true;
                delete curr;
-               curr = tmp;
+               curr=tmp;
        } else {
-               /*
-                * Perform one-time actions when pushing new ModelAction onto
-                * NodeStack
-                */
-               curr->create_cv(get_parent_action(curr->get_tid()));
-               /* Build may_read_from set */
-               if (curr->is_read())
-                       build_reads_from_past(curr);
+               ModelAction * tmp = node_stack->explore_action(curr);
+               if (tmp) {
+                       /* Discard duplicate ModelAction; use action from NodeStack */
+                       /* First restore type and order in case of RMW operation */
+                       if (curr->is_rmwr())
+                               tmp->copy_typeandorder(curr);
+                       delete curr;
+                       curr = tmp;
+               } else {
+                       /*
+                        * Perform one-time actions when pushing new ModelAction onto
+                        * NodeStack
+                        */
+                       curr->create_cv(get_parent_action(curr->get_tid()));
+                       /* Build may_read_from set */
+                       if (curr->is_read())
+                               build_reads_from_past(curr);
+               }
        }
 
        /* Assign 'creation' parent */
@@ -271,20 +288,7 @@ void ModelChecker::check_current_action(void)
                th->set_creation(curr);
        }
 
-       nextThread = get_next_replay_thread();
-
-       Node *currnode = curr->get_node();
-       Node *parnode = currnode->get_parent();
-
-       if (!parnode->backtrack_empty()||!currnode->readsfrom_empty())
-               if (!next_backtrack || *curr > *next_backtrack)
-                       next_backtrack = curr;
-
-       set_backtracking(curr);
-
        /* Assign reads_from values */
-       /* TODO: perform release/acquire synchronization here; include
-        * reads_from as ModelAction member? */
        Thread *th = get_thread(curr->get_tid());
        uint64_t value = VALUE_NONE;
        if (curr->is_read()) {
@@ -299,14 +303,51 @@ void ModelChecker::check_current_action(void)
 
        th->set_return_value(value);
 
-       /* Add action to list last.  */
-       add_action_to_lists(curr);
+       /* Add action to list.  */
+       if (!already_added)
+               add_action_to_lists(curr);
+
+       /* Is there a better interface for setting the next thread rather
+                than this field/convoluted approach?  Perhaps like just returning
+                it or something? */
+
+       /* Do not split atomic actions. */
+       if (curr->is_rmwr()) {
+               nextThread = thread_current()->get_id();
+       } else {
+               nextThread = get_next_replay_thread();
+       }
+
+       Node *currnode = curr->get_node();
+       Node *parnode = currnode->get_parent();
+
+       if (!parnode->backtrack_empty()||!currnode->readsfrom_empty())
+               if (!next_backtrack || *curr > *next_backtrack)
+                       next_backtrack = curr;
+
+       set_backtracking(curr);
 }
 
+/** @returns whether the current trace is feasible. */
 bool ModelChecker::isfeasible() {
        return !cyclegraph->checkForCycles();
 }
 
+/** 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);
+       lastread->process_rmw(act);
+       if (act->is_rmw())
+               cyclegraph->addRMWEdge(lastread, lastread->get_reads_from());
+       return lastread;
+}
+
+/**
+ * Updates the cyclegraph with the constraints imposed from the current read.
+ * @param curr The current action. Must be a read.
+ * @param rf The action that curr reads from. Must be a write.
+ */
 void ModelChecker::r_modification_order(ModelAction * curr, const ModelAction *rf) {
        std::vector<action_list_t> *thrd_lists = &(*obj_thrd_map)[curr->get_location()];
        unsigned int i;
@@ -335,6 +376,10 @@ void ModelChecker::r_modification_order(ModelAction * curr, const ModelAction *r
        }
 }
 
+/**
+ * Updates the cyclegraph with the constraints imposed from the current write.
+ * @param curr The current action. Must be a write.
+ */
 void ModelChecker::w_modification_order(ModelAction * curr) {
        std::vector<action_list_t> *thrd_lists = &(*obj_thrd_map)[curr->get_location()];
        unsigned int i;
@@ -425,6 +470,11 @@ ModelAction * ModelChecker::get_parent_action(thread_id_t tid)
        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) {
        return get_parent_action(tid)->get_cv();
 }
@@ -489,7 +539,7 @@ void ModelChecker::build_reads_from_past(ModelAction *curr)
                /* TODO: need a more informative way of reporting errors */
                printf("ERROR: may read from uninitialized atomic\n");
        }
-       
+
        if (DBG_ENABLED() || !initialized) {
                printf("Reached read action:\n");
                curr->print();
@@ -497,7 +547,7 @@ void ModelChecker::build_reads_from_past(ModelAction *curr)
                curr->get_node()->print_may_read_from();
                printf("End printing may_read_from\n");
        }
-       
+
        ASSERT(initialized);
 }
 
@@ -519,11 +569,11 @@ void ModelChecker::print_summary(void)
        printf("\n");
        printf("Number of executions: %d\n", num_executions);
        printf("Total nodes created: %d\n", node_stack->get_total_nodes());
-       if (!isfeasible())
-               printf("INFEASIBLE EXECUTION!\n");
 
        scheduler->print();
 
+       if (!isfeasible())
+               printf("INFEASIBLE EXECUTION!\n");
        print_list(action_trace);
        printf("\n");
 }
@@ -553,10 +603,8 @@ void ModelChecker::remove_thread(Thread *t)
  */
 int ModelChecker::switch_to_master(ModelAction *act)
 {
-       Thread *old;
-
        DBG();
-       old = thread_current();
+       Thread * old = thread_current();
        set_current_action(act);
        old->set_state(THREAD_READY);
        return Thread::swap(old, get_system_context());