a bug fix
[cdsspec-compiler.git] / model.cc
index 1711e1a002b6d105cb413efec6c20e644f51f0f8..0006fd63d66e172336df1296c417a787fe559d2a 100644 (file)
--- a/model.cc
+++ b/model.cc
@@ -25,6 +25,7 @@ ModelChecker::ModelChecker(struct model_params params) :
        num_executions(0),
        num_feasible_executions(0),
        diverge(NULL),
+       earliest_diverge(NULL),
        action_trace(new action_list_t()),
        thread_map(new HashTable<int, Thread *, int>()),
        obj_map(new HashTable<const void *, action_list_t, uintptr_t, 4>()),
@@ -38,7 +39,8 @@ ModelChecker::ModelChecker(struct model_params params) :
        mo_graph(new CycleGraph()),
        failed_promise(false),
        too_many_reads(false),
-       asserted(false)
+       asserted(false),
+       bad_synchronization(false)
 {
        /* Allocate this "size" on the snapshotting heap */
        priv = (struct model_snapshot_members *)calloc(1, sizeof(*priv));
@@ -80,6 +82,7 @@ void ModelChecker::reset_to_initial_state()
        node_stack->reset_execution();
        failed_promise = false;
        too_many_reads = false;
+       bad_synchronization = false;
        reset_asserted();
        snapshotObject->backTrackBeforeStep(0);
 }
@@ -136,6 +139,9 @@ Thread * ModelChecker::get_next_thread(ModelAction *curr)
        ModelAction *next = node_stack->get_next()->get_action();
 
        if (next == diverge) {
+               if (earliest_diverge == NULL || *diverge < *earliest_diverge)
+                       earliest_diverge=diverge;
+
                Node *nextnode = next->get_node();
                /* Reached divergence point */
                if (nextnode->increment_promise()) {
@@ -155,8 +161,12 @@ Thread * ModelChecker::get_next_thread(ModelAction *curr)
                        Node *node = nextnode->get_parent();
                        tid = node->get_next_backtrack();
                        node_stack->pop_restofstack(1);
+                       if (diverge==earliest_diverge) {
+                               earliest_diverge=node->get_action();
+                       }
                }
                DEBUG("*** Divergence point ***\n");
+
                diverge = NULL;
        } else {
                tid = next->get_tid();
@@ -178,8 +188,16 @@ bool ModelChecker::next_execution()
        DBG();
 
        num_executions++;
-       if (isfinalfeasible())
+       if (isfinalfeasible()) {
+               printf("Earliest divergence point since last feasible execution:\n");
+               if (earliest_diverge)
+                       earliest_diverge->print();
+               else
+                       printf("(Not set)\n");
+
+               earliest_diverge = NULL;
                num_feasible_executions++;
+       }
 
        if (isfinalfeasible() || DBG_ENABLED())
                print_summary();
@@ -523,7 +541,9 @@ ModelAction * ModelChecker::initialize_curr_action(ModelAction *curr)
        if (curr->is_rmwc() || curr->is_rmw()) {
                newcurr = process_rmw(curr);
                delete curr;
-               compute_promises(newcurr);
+
+               if (newcurr->is_rmw())
+                       compute_promises(newcurr);
                return newcurr;
        }
 
@@ -539,18 +559,19 @@ ModelAction * ModelChecker::initialize_curr_action(ModelAction *curr)
                /* Discard duplicate ModelAction; use action from NodeStack */
                delete curr;
 
-               /* If we have diverged, we need to reset the clock vector. */
-               if (diverge == NULL)
-                       newcurr->create_cv(get_parent_action(newcurr->get_tid()));
+               /* Always compute new clock vector */
+               newcurr->create_cv(get_parent_action(newcurr->get_tid()));
        } else {
                newcurr = curr;
+
+               /* Always compute new clock vector */
+               newcurr->create_cv(get_parent_action(newcurr->get_tid()));
                /*
                 * Perform one-time actions when pushing new ModelAction onto
                 * NodeStack
                 */
-               curr->create_cv(get_parent_action(curr->get_tid()));
-               if (curr->is_write())
-                       compute_promises(curr);
+               if (newcurr->is_write())
+                       compute_promises(newcurr);
        }
        return newcurr;
 }
@@ -653,7 +674,8 @@ Thread * ModelChecker::check_current_action(ModelAction *curr)
                        bool updated = false;
 
                        if (act->is_read()) {
-                               if (r_modification_order(act, act->get_reads_from()))
+                               const ModelAction *rf = act->get_reads_from();
+                               if (rf != NULL && r_modification_order(act, rf))
                                        updated = true;
                        }
                        if (act->is_write()) {
@@ -740,10 +762,12 @@ bool ModelChecker::isfeasibleotherthanRMW() {
                        DEBUG("Infeasible: failed promise\n");
                if (too_many_reads)
                        DEBUG("Infeasible: too many reads\n");
+               if (bad_synchronization)
+                       DEBUG("Infeasible: bad synchronization ordering\n");
                if (promises_expired())
                        DEBUG("Infeasible: promises expired\n");
        }
-       return !mo_graph->checkForCycles() && !failed_promise && !too_many_reads && !promises_expired();
+       return !mo_graph->checkForCycles() && !failed_promise && !too_many_reads && !bad_synchronization && !promises_expired();
 }
 
 /** Returns whether the current completed trace is feasible. */
@@ -944,10 +968,10 @@ void ModelChecker::post_r_modification_order(ModelAction *curr, const ModelActio
                action_list_t::reverse_iterator rit;
                ModelAction *lastact = NULL;
 
-               /* Find last action that happens after curr */
+               /* Find last action that happens after curr that is either not curr or a rmw */
                for (rit = list->rbegin(); rit != list->rend(); rit++) {
                        ModelAction *act = *rit;
-                       if (curr->happens_before(act)) {
+                       if (curr->happens_before(act) && (curr != act || curr->is_rmw())) {
                                lastact = act;
                        } else
                                break;
@@ -955,12 +979,25 @@ void ModelChecker::post_r_modification_order(ModelAction *curr, const ModelActio
 
                        /* Include at most one act per-thread that "happens before" curr */
                if (lastact != NULL) {
-                       if (lastact->is_read()) {
+                       if (lastact==curr) {
+                               //Case 1: The resolved read is a RMW, and we need to make sure
+                               //that the write portion of the RMW mod order after rf
+
+                               mo_graph->addEdge(rf, lastact);
+                       } else if (lastact->is_read()) {
+                               //Case 2: The resolved read is a normal read and the next
+                               //operation is a read, and we need to make sure the value read
+                               //is mod ordered after rf
+
                                const ModelAction *postreadfrom = lastact->get_reads_from();
                                if (postreadfrom != NULL&&rf != postreadfrom)
                                        mo_graph->addEdge(rf, postreadfrom);
-                       } else if (rf != lastact) {
-                               mo_graph->addEdge(rf, lastact);
+                       } else {
+                               //Case 3: The resolved read is a normal read and the next
+                               //operation is a write, and we need to make sure that the
+                               //write is mod ordered after rf
+                               if (lastact!=rf)
+                                       mo_graph->addEdge(rf, lastact);
                        }
                        break;
                }
@@ -1276,8 +1313,10 @@ bool ModelChecker::resolve_release_sequences(void *location, work_queue_t *work_
                complete = release_seq_head(rf, &release_heads);
                for (unsigned int i = 0; i < release_heads.size(); i++) {
                        if (!act->has_synchronized_with(release_heads[i])) {
-                               updated = true;
-                               act->synchronize_with(release_heads[i]);
+                               if (act->synchronize_with(release_heads[i]))
+                                       updated = true;
+                               else
+                                       set_bad_synchronization();
                        }
                }
 
@@ -1430,6 +1469,8 @@ bool ModelChecker::resolve_promises(ModelAction *write)
                        //Next fix up the modification order for actions that happened
                        //after the read.
                        post_r_modification_order(read, write);
+                       //Make sure the promise's value matches the write's value
+                       ASSERT(promise->get_value() == write->get_value());
 
                        promises->erase(promises->begin() + promise_index);
                        resolved = true;
@@ -1564,6 +1605,33 @@ static void print_list(action_list_t *list)
        printf("---------------------------------------------------------------------\n");
 }
 
+#if SUPPORT_MOD_ORDER_DUMP
+void ModelChecker::dumpGraph(char *filename) {
+       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 *action=*it;
+               if (action->is_read()) {
+                       fprintf(file, "N%u [label=\"%u, T%u\"];\n", action->get_seq_number(),action->get_seq_number(), action->get_tid());
+                       fprintf(file, "N%u -> N%u[label=\"rf\", color=red];\n", action->get_seq_number(), action->get_reads_from()->get_seq_number());
+               }
+               if (thread_array[action->get_tid()] != NULL) {
+                       fprintf(file, "N%u -> N%u[label=\"sb\", color=blue];\n", thread_array[action->get_tid()]->get_seq_number(), action->get_seq_number());
+               }
+               
+               thread_array[action->get_tid()]=action;
+       }
+  fprintf(file,"}\n");
+       model_free(thread_array);
+  fclose(file);        
+}
+#endif
+
 void ModelChecker::print_summary()
 {
        printf("\n");
@@ -1576,6 +1644,8 @@ void ModelChecker::print_summary()
        char buffername[100];
        sprintf(buffername, "exec%04u", num_executions);
        mo_graph->dumpGraphToFile(buffername);
+       sprintf(buffername, "graph%04u", num_executions);
+  dumpGraph(buffername);
 #endif
 
        if (!isfinalfeasible())
@@ -1636,6 +1706,7 @@ bool ModelChecker::take_step() {
 
                        priv->nextThread = check_current_action(priv->current_action);
                        priv->current_action = NULL;
+
                        if (curr->is_blocked() || curr->is_complete())
                                scheduler->remove_thread(curr);
                } else {