model: remove ModelChecker::is_infeasible_ignoreRMW()
[c11tester.git] / model.cc
index f2d40fe6f724022ee2b50c783df310ce0b47ff99..9e611fae96367283e33d7b927224eb259b52a27e 100644 (file)
--- a/model.cc
+++ b/model.cc
@@ -614,7 +614,7 @@ void ModelChecker::set_backtracking(ModelAction *act)
        Node *node = prev->get_node()->get_parent();
 
        int low_tid, high_tid;
-       if (node->is_enabled(t)) {
+       if (node->enabled_status(t->get_id()) == THREAD_ENABLED) {
                low_tid = id_to_int(act->get_tid());
                high_tid = low_tid + 1;
        } else {
@@ -721,7 +721,6 @@ bool ModelChecker::process_read(ModelAction *curr, bool second_part_of_rmw)
                                r_status = r_modification_order(curr, reads_from);
                        }
 
-
                        if (!second_part_of_rmw && is_infeasible() && (curr->get_node()->increment_read_from() || curr->get_node()->increment_future_value())) {
                                mo_graph->rollbackChanges();
                                priv->too_many_reads = false;
@@ -730,16 +729,16 @@ bool ModelChecker::process_read(ModelAction *curr, bool second_part_of_rmw)
 
                        read_from(curr, reads_from);
                        mo_graph->commitChanges();
-                       mo_check_promises(curr->get_tid(), reads_from);
+                       mo_check_promises(curr->get_tid(), reads_from, NULL);
 
                        updated |= r_status;
                } else if (!second_part_of_rmw) {
                        /* Read from future value */
-                       value = curr->get_node()->get_future_value();
-                       modelclock_t expiration = curr->get_node()->get_future_value_expiration();
+                       struct future_value fv = curr->get_node()->get_future_value();
+                       value = fv.value;
+                       curr->set_value(fv.value);
                        curr->set_read_from(NULL);
-                       Promise *valuepromise = new Promise(curr, value, expiration);
-                       promises->push_back(valuepromise);
+                       promises->push_back(new Promise(curr, fv));
                }
                get_thread(curr)->set_return_value(value);
                return updated;
@@ -856,10 +855,22 @@ bool ModelChecker::process_mutex(ModelAction *curr)
 void ModelChecker::add_future_value(const ModelAction *writer, ModelAction *reader)
 {
        /* Do more ambitious checks now that mo is more complete */
-       if (mo_may_allow(writer, reader) &&
-                       reader->get_node()->add_future_value(writer->get_value(),
-                               writer->get_seq_number() + params.maxfuturedelay))
-               set_latest_backtrack(reader);
+       if (mo_may_allow(writer, reader)) {
+               Node *node = reader->get_node();
+
+               /* Find an ancestor thread which exists at the time of the reader */
+               Thread *write_thread = get_thread(writer);
+               while (id_to_int(write_thread->get_id()) >= node->get_num_threads())
+                       write_thread = write_thread->get_parent();
+
+               struct future_value fv = {
+                       writer->get_value(),
+                       writer->get_seq_number() + params.maxfuturedelay,
+                       write_thread->get_id(),
+               };
+               if (node->add_future_value(fv))
+                       set_latest_backtrack(reader);
+       }
 }
 
 /**
@@ -881,7 +892,7 @@ bool ModelChecker::process_write(ModelAction *curr)
        }
 
        mo_graph->commitChanges();
-       mo_check_promises(curr->get_tid(), curr);
+       mo_check_promises(curr->get_tid(), curr, NULL);
 
        get_thread(curr)->set_return_value(VALUE_NONE);
        return updated_mod_order || updated_promises;
@@ -956,6 +967,12 @@ bool ModelChecker::process_thread_action(ModelAction *curr)
        case THREAD_CREATE: {
                Thread *th = curr->get_thread_operand();
                th->set_creation(curr);
+               /* Promises can be satisfied by children */
+               for (unsigned int i = 0; i < promises->size(); i++) {
+                       Promise *promise = (*promises)[i];
+                       if (promise->thread_is_available(curr->get_tid()))
+                               promise->add_thread(th->get_id());
+               }
                break;
        }
        case THREAD_JOIN: {
@@ -972,6 +989,13 @@ bool ModelChecker::process_thread_action(ModelAction *curr)
                        scheduler->wake(get_thread(act));
                }
                th->complete();
+               /* Completed thread can't satisfy promises */
+               for (unsigned int i = 0; i < promises->size(); i++) {
+                       Promise *promise = (*promises)[i];
+                       if (promise->thread_is_available(th->get_id()))
+                               if (promise->eliminate_thread(th->get_id()))
+                                       priv->failed_promise = true;
+               }
                updated = true; /* trigger rel-seq checks */
                break;
        }
@@ -1361,7 +1385,7 @@ void ModelChecker::print_infeasibility(const char *prefix) const
        if (promises_expired())
                ptr += sprintf(ptr, "[promise expired]");
        if (promises->size() != 0)
-               ptr += sprintf(ptr, "[unrevolved promise]");
+               ptr += sprintf(ptr, "[unresolved promise]");
        if (ptr != buf)
                model_print("%s: %s\n", prefix ? prefix : "Infeasible", buf);
 }
@@ -1383,21 +1407,11 @@ bool ModelChecker::is_feasible_prefix_ignore_relseq() const
  */
 bool ModelChecker::is_infeasible() const
 {
-       return mo_graph->checkForRMWViolation() || is_infeasible_ignoreRMW();
-}
-
-/**
- * Check If the current partial trace is infeasible, while ignoring
- * infeasibility related to 2 RMW's reading from the same store. It does not
- * check end-of-execution feasibility.
- * @see ModelChecker::is_infeasible
- * @return whether the current partial trace is infeasible, ignoring multiple
- * RMWs reading from the same store.
- * */
-bool ModelChecker::is_infeasible_ignoreRMW() const
-{
-       return mo_graph->checkForCycles() || priv->failed_promise ||
-               priv->too_many_reads || priv->bad_synchronization ||
+       return mo_graph->checkForRMWViolation() ||
+               mo_graph->checkForCycles() ||
+               priv->failed_promise ||
+               priv->too_many_reads ||
+               priv->bad_synchronization ||
                promises_expired();
 }
 
@@ -1786,10 +1800,10 @@ bool ModelChecker::w_modification_order(ModelAction *curr)
 
                                 */
                                if (thin_air_constraint_may_allow(curr, act)) {
-                                       if (!is_infeasible() ||
-                                                       (curr->is_rmw() && act->is_rmw() && curr->get_reads_from() == act->get_reads_from() && !is_infeasible_ignoreRMW())) {
+                                       if (!is_infeasible())
                                                futurevalues->push_back(PendingFutureValue(curr, act));
-                                       }
+                                       else if (curr->is_rmw() && act->is_rmw() && curr->get_reads_from() && curr->get_reads_from() == act->get_reads_from())
+                                               add_future_value(curr, act);
                                }
                        }
                }
@@ -2310,7 +2324,7 @@ ClockVector * ModelChecker::get_cv(thread_id_t tid) const
 bool ModelChecker::resolve_promises(ModelAction *write)
 {
        bool resolved = false;
-       std::vector< thread_id_t, ModelAlloc<thread_id_t> > threads_to_check;
+       std::vector< ModelAction *, ModelAlloc<ModelAction *> > actions_to_check;
 
        for (unsigned int i = 0, promise_index = 0; promise_index < promises->size(); i++) {
                Promise *promise = (*promises)[promise_index];
@@ -2331,7 +2345,7 @@ bool ModelChecker::resolve_promises(ModelAction *write)
                        delete(promise);
 
                        promises->erase(promises->begin() + promise_index);
-                       threads_to_check.push_back(read->get_tid());
+                       actions_to_check.push_back(read);
 
                        resolved = true;
                } else
@@ -2341,8 +2355,10 @@ bool ModelChecker::resolve_promises(ModelAction *write)
        //Check whether reading these writes has made threads unable to
        //resolve promises
 
-       for (unsigned int i = 0; i < threads_to_check.size(); i++)
-               mo_check_promises(threads_to_check[i], write);
+       for (unsigned int i = 0; i < actions_to_check.size(); i++) {
+               ModelAction *read=actions_to_check[i];
+               mo_check_promises(read->get_tid(), write, read);
+       }
 
        return resolved;
 }
@@ -2377,7 +2393,7 @@ void ModelChecker::check_promises(thread_id_t tid, ClockVector *old_cv, ClockVec
                const ModelAction *act = promise->get_action();
                if ((old_cv == NULL || !old_cv->synchronized_since(act)) &&
                                merge_cv->synchronized_since(act)) {
-                       if (promise->increment_threads(tid)) {
+                       if (promise->eliminate_thread(tid)) {
                                //Promise has failed
                                priv->failed_promise = true;
                                return;
@@ -2386,29 +2402,34 @@ void ModelChecker::check_promises(thread_id_t tid, ClockVector *old_cv, ClockVec
        }
 }
 
-void ModelChecker::check_promises_thread_disabled() {
+void ModelChecker::check_promises_thread_disabled()
+{
        for (unsigned int i = 0; i < promises->size(); i++) {
                Promise *promise = (*promises)[i];
-               if (promise->check_promise()) {
+               if (promise->has_failed()) {
                        priv->failed_promise = true;
                        return;
                }
        }
 }
 
-/** Checks promises in response to addition to modification order for threads.
+/**
+ * @brief Checks promises in response to addition to modification order for
+ * threads.
+ *
  * Definitions:
+ *
  * pthread is the thread that performed the read that created the promise
  *
  * pread is the read that created the promise
  *
  * pwrite is either the first write to same location as pread by
- * pthread that is sequenced after pread or the value read by the
- * first read to the same lcoation as pread by pthread that is
- * sequenced after pread..
+ * pthread that is sequenced after pread or the write read by the
+ * first read to the same location as pread by pthread that is
+ * sequenced after pread.
  *
- *     1. If tid=pthread, then we check what other threads are reachable
- * through the mode order starting with pwrite.  Those threads cannot
+ * 1. If tid=pthread, then we check what other threads are reachable
+ * through the mod order starting with pwrite.  Those threads cannot
  * perform a write that will resolve the promise due to modification
  * order constraints.
  *
@@ -2417,46 +2438,50 @@ void ModelChecker::check_promises_thread_disabled() {
  * cannot perform a future write that will resolve the promise due to
  * modificatin order constraints.
  *
- *     @param tid The thread that either read from the model action
- *     write, or actually did the model action write.
+ * @param tid The thread that either read from the model action write, or
+ * actually did the model action write.
  *
- *     @param write The ModelAction representing the relevant write.
+ * @param write The ModelAction representing the relevant write.
+ * @param read  The ModelAction that reads a promised write, or NULL otherwise.
  */
-void ModelChecker::mo_check_promises(thread_id_t tid, const ModelAction *write)
+void ModelChecker::mo_check_promises(thread_id_t tid, const ModelAction *write, const ModelAction *read)
 {
        void *location = write->get_location();
        for (unsigned int i = 0; i < promises->size(); i++) {
                Promise *promise = (*promises)[i];
                const ModelAction *act = promise->get_action();
 
-               //Is this promise on the same location?
+               // Is this promise on the same location?
                if (act->get_location() != location)
                        continue;
 
-               //same thread as the promise
+               // same thread as the promise
                if (act->get_tid() == tid) {
+                       // make sure that the reader of this write happens after the promise
+                       if ((read == NULL) || (promise->get_action()->happens_before(read))) {
+                               // do we have a pwrite for the promise, if not, set it
+                               if (promise->get_write() == NULL) {
+                                       promise->set_write(write);
+                                       // The pwrite cannot happen before the promise
+                                       if (write->happens_before(act) && (write != act)) {
+                                               priv->failed_promise = true;
+                                               return;
+                                       }
+                               }
 
-                       //do we have a pwrite for the promise, if not, set it
-                       if (promise->get_write() == NULL) {
-                               promise->set_write(write);
-                               //The pwrite cannot happen before the promise
-                               if (write->happens_before(act) && (write != act)) {
+                               if (mo_graph->checkPromise(write, promise)) {
                                        priv->failed_promise = true;
                                        return;
                                }
                        }
-                       if (mo_graph->checkPromise(write, promise)) {
-                               priv->failed_promise = true;
-                               return;
-                       }
                }
 
-               //Don't do any lookups twice for the same thread
-               if (promise->has_sync_thread(tid))
+               // Don't do any lookups twice for the same thread
+               if (!promise->thread_is_available(tid))
                        continue;
 
                if (promise->get_write() && mo_graph->checkReachable(promise->get_write(), write)) {
-                       if (promise->increment_threads(tid)) {
+                       if (promise->eliminate_thread(tid)) {
                                priv->failed_promise = true;
                                return;
                        }
@@ -2576,13 +2601,11 @@ ModelAction * ModelChecker::new_uninitialized_action(void *location) const
        return act;
 }
 
-static void print_list(action_list_t *list, int exec_num = -1)
+static void print_list(action_list_t *list)
 {
        action_list_t::iterator it;
 
        model_print("---------------------------------------------------------------------\n");
-       if (exec_num >= 0)
-               model_print("Execution %d:\n", exec_num);
 
        unsigned int hash = 0;
 
@@ -2635,9 +2658,12 @@ void ModelChecker::print_summary() const
        dumpGraph(buffername);
 #endif
 
-       if (!isfeasibleprefix())
-               print_infeasibility("INFEASIBLE EXECUTION");
-       print_list(action_trace, stats.num_total);
+       model_print("Execution %d:", stats.num_total);
+       if (isfeasibleprefix())
+               model_print("\n");
+       else
+               print_infeasibility(" INFEASIBLE");
+       print_list(action_trace);
        model_print("\n");
 }
 
@@ -2676,7 +2702,7 @@ Thread * ModelChecker::get_thread(thread_id_t tid) const
  * @param act The ModelAction
  * @return A Thread reference
  */
-Thread * ModelChecker::get_thread(ModelAction *act) const
+Thread * ModelChecker::get_thread(const ModelAction *act) const
 {
        return get_thread(act->get_tid());
 }