forgot about events that happen after an unresolved read... bug fix checked in
[model-checker.git] / model.cc
index d8699b0ebfe850b3a0a8d3d277f3ca914db0b59f..2b2a5f0ecef177282c4a065d8ac4a91d01eb20dc 100644 (file)
--- a/model.cc
+++ b/model.cc
@@ -133,7 +133,7 @@ thread_id_t ModelChecker::get_next_replay_thread()
        if (next == diverge) {
                Node *nextnode = next->get_node();
                /* Reached divergence point */
-               if (nextnode->increment_promises()) {
+               if (nextnode->increment_promise()) {
                        /* The next node will try to satisfy a different set of promises. */
                        tid = next->get_tid();
                        node_stack->pop_restofstack(2);
@@ -141,7 +141,7 @@ thread_id_t ModelChecker::get_next_replay_thread()
                        /* The next node will read from a different value. */
                        tid = next->get_tid();
                        node_stack->pop_restofstack(2);
-               } else if (nextnode->increment_future_values()) {
+               } else if (nextnode->increment_future_value()) {
                        /* The next node will try to read from a different future value. */
                        tid = next->get_tid();
                        node_stack->pop_restofstack(2);
@@ -173,7 +173,7 @@ bool ModelChecker::next_execution()
 
        num_executions++;
 
-       if (isfeasible() || DBG_ENABLED())
+       if (isfinalfeasible() || DBG_ENABLED())
                print_summary();
 
        if ((diverge = model->get_next_backtrack()) == NULL)
@@ -279,6 +279,12 @@ void ModelChecker::check_current_action(void)
                        /* First restore type and order in case of RMW operation */
                        if (curr->is_rmwr())
                                tmp->copy_typeandorder(curr);
+
+                       /* If we have diverged, we need to reset the clock vector. */
+                       if (diverge==NULL) {
+                               tmp->create_cv(get_parent_action(tmp->get_tid()));
+                       }
+
                        delete curr;
                        curr = tmp;
                } else {
@@ -348,18 +354,23 @@ void ModelChecker::check_current_action(void)
        Node *currnode = curr->get_node();
        Node *parnode = currnode->get_parent();
 
-       if (!parnode->backtrack_empty()||!currnode->readsfrom_empty()||!currnode->futurevalues_empty()||!currnode->promises_empty())
+       if (!parnode->backtrack_empty()||!currnode->read_from_empty()||!currnode->future_value_empty()||!currnode->promise_empty())
                if (!next_backtrack || *curr > *next_backtrack)
                        next_backtrack = curr;
-       
+
        set_backtracking(curr);
 }
 
-/** @returns whether the current trace is feasible. */
+/** @returns whether the current partial trace is feasible. */
 bool ModelChecker::isfeasible() {
        return !cyclegraph->checkForCycles() && !failed_promise;
 }
 
+/** Returns whether the current completed trace is feasible. */
+bool ModelChecker::isfinalfeasible() {
+       return isfeasible() && promises->size()==0;
+}
+
 /** 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());
@@ -392,7 +403,7 @@ void ModelChecker::r_modification_order(ModelAction * curr, const ModelAction *r
                        if (act->happens_before(curr)) {
                                if (act->is_read()) {
                                        const ModelAction * prevreadfrom=act->get_reads_from();
-                                       if (rf!=prevreadfrom)
+                                       if (prevreadfrom!=NULL&&rf!=prevreadfrom)
                                                cyclegraph->addEdge(rf, prevreadfrom);
                                } else if (rf!=act) {
                                        cyclegraph->addEdge(rf, act);
@@ -403,6 +414,43 @@ void ModelChecker::r_modification_order(ModelAction * curr, const ModelAction *r
        }
 }
 
+/** Updates the cyclegraph with the constraints imposed from the
+ *  current read. */
+void ModelChecker::post_r_modification_order(ModelAction * curr, const ModelAction *rf) {
+       std::vector<action_list_t> *thrd_lists = obj_thrd_map->ensureptr(curr->get_location());
+       unsigned int i;
+       ASSERT(curr->is_read());
+
+       /* 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;
+               ModelAction *lastact=NULL;
+
+               /* Find last action that happens after curr */
+               for (rit = list->rbegin(); rit != list->rend(); rit++) {
+                       ModelAction *act = *rit;
+                       if (curr->happens_before(act)) {
+                               lastact=act;
+                       } else
+                               break;
+               }
+
+                       /* Include at most one act per-thread that "happens before" curr */
+               if (lastact!=NULL) {
+                       if (lastact->is_read()) {
+                               const ModelAction * postreadfrom=lastact->get_reads_from();
+                               if (postreadfrom!=NULL&&rf!=postreadfrom)
+                                       cyclegraph->addEdge(postreadfrom, rf);
+                       } else if (rf!=lastact) {
+                               cyclegraph->addEdge(lastact, rf);
+                       }
+                       break;
+               }
+       }
+}
+
 /**
  * Updates the cyclegraph with the constraints imposed from the current write.
  * @param curr The current action. Must be a write.
@@ -441,11 +489,10 @@ void ModelChecker::w_modification_order(ModelAction * curr) {
                                                 (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 
+                                                (4) is in a different thread
                                                 =>
                                                 that read could potentially read from our write.
                                        */
-
                                        if (act->get_node()->add_future_value(curr->get_value())&&
                                                        (!next_backtrack || *act > * next_backtrack))
                                                next_backtrack = act;
@@ -522,19 +569,25 @@ ClockVector * ModelChecker::get_cv(thread_id_t tid) {
 }
 
 
-/** Resolve promises. */
+/** Resolve the given promises. */
 
 void ModelChecker::resolve_promises(ModelAction *write) {
-       for(unsigned int i=0;i<promises->size();i++) {
-               Promise * promise=(*promises)[i];
+       for(unsigned int i=0, promise_index=0;promise_index<promises->size(); i++) {
+               Promise * promise=(*promises)[promise_index];
                if (write->get_node()->get_promise(i)) {
                        ModelAction * read=promise->get_action();
                        read->read_from(write);
                        r_modification_order(read, write);
-               }
+                       post_r_modification_order(read, write);
+                       promises->erase(promises->begin()+promise_index);
+               } else
+                       promise_index++;
        }
 }
 
+/** Compute the set of promises that could potentially be satisfied by
+ *  this action. */
+
 void ModelChecker::compute_promises(ModelAction *curr) {
        for(unsigned int i=0;i<promises->size();i++) {
                Promise * promise=(*promises)[i];
@@ -601,7 +654,7 @@ void ModelChecker::build_reads_from_past(ModelAction *curr)
                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())
                                continue;
@@ -661,7 +714,7 @@ void ModelChecker::print_summary(void)
 
        scheduler->print();
 
-       if (!isfeasible())
+       if (!isfinalfeasible())
                printf("INFEASIBLE EXECUTION!\n");
        print_list(action_trace);
        printf("\n");