model: bugfix - inherit future values from previous loads

[c11tester.git] / model.cc

diff --git a/model.cc b/model.cc
index 8f0b3ce443c4bf9d18eedbf524cd2d6e3c7b91fe..ae3788945c7756881178b1657bb215cf5a71901a 100644 (file)
--- a/model.cc
+++ b/model.cc
@@ -313,14 +313,41 @@ void ModelChecker::execute_sleep_set()
        }
 }
 
+/**
+ * @brief Should the current action wake up a given thread?
+ *
+ * @param curr The current action
+ * @param thread The thread that we might wake up
+ * @return True, if we should wake up the sleeping thread; false otherwise
+ */
+bool ModelChecker::should_wake_up(const ModelAction *curr, const Thread *thread) const
+{
+       const ModelAction *asleep = thread->get_pending();
+       /* Don't allow partial RMW to wake anyone up */
+       if (curr->is_rmwr())
+               return false;
+       /* Synchronizing actions may have been backtracked */
+       if (asleep->could_synchronize_with(curr))
+               return true;
+       /* All acquire/release fences and fence-acquire/store-release */
+       if (asleep->is_fence() && asleep->is_acquire() && curr->is_release())
+               return true;
+       /* Fence-release + store can awake load-acquire on the same location */
+       if (asleep->is_read() && asleep->is_acquire() && curr->same_var(asleep) && curr->is_write()) {
+               ModelAction *fence_release = get_last_fence_release(curr->get_tid());
+               if (fence_release && *(get_last_action(thread->get_id())) < *fence_release)
+                       return true;
+       }
+       return false;
+}
+
 void ModelChecker::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)) {
-                       ModelAction *pending_act = thr->get_pending();
-                       if ((!curr->is_rmwr()) && pending_act->could_synchronize_with(curr))
-                               //Remove this thread from sleep set
+                       if (should_wake_up(curr, thr))
+                               /* Remove this thread from sleep set */
                                scheduler->remove_sleep(thr);
                }
        }
@@ -1366,7 +1393,7 @@ ModelAction * ModelChecker::check_current_action(ModelAction *curr)
 
        /* Build may_read_from set for newly-created actions */
        if (newly_explored && curr->is_read())
-               build_reads_from_past(curr);
+               build_may_read_from(curr);
 
        /* Initialize work_queue with the "current action" work */
        work_queue_t work_queue(1, CheckCurrWorkEntry(curr));
@@ -2541,12 +2568,12 @@ void ModelChecker::compute_relseq_breakwrites(ModelAction *curr)
 
 /**
  * Build up an initial set of all past writes that this 'read' action may read
- * from. This set is determined by the clock vector's "happens before"
- * relationship.
+ * from, as well as any previously-observed future values that must still be valid.
+ *
  * @param curr is the current ModelAction that we are exploring; it must be a
  * 'read' operation.
  */
-void ModelChecker::build_reads_from_past(ModelAction *curr)
+void ModelChecker::build_may_read_from(ModelAction *curr)
 {
        std::vector<action_list_t> *thrd_lists = get_safe_ptr_vect_action(obj_thrd_map, curr->get_location());
        unsigned int i;
@@ -2591,8 +2618,25 @@ void ModelChecker::build_reads_from_past(ModelAction *curr)
                                break;
                }
        }
+
+       /* Inherit existing, promised future values */
+       for (i = 0; i < promises->size(); i++) {
+               const Promise *promise = (*promises)[i];
+               const ModelAction *promise_read = promise->get_action();
+               if (promise_read->same_var(curr)) {
+                       /* Only add feasible future-values */
+                       mo_graph->startChanges();
+                       r_modification_order(curr, promise);
+                       if (!is_infeasible()) {
+                               const struct future_value fv = promise->get_fv();
+                               curr->get_node()->add_future_value(fv);
+                       }
+                       mo_graph->rollbackChanges();
+               }
+       }
+
        /* We may find no valid may-read-from only if the execution is doomed */
-       if (!curr->get_node()->get_read_from_size()) {
+       if (!curr->get_node()->get_read_from_size() && curr->get_node()->future_value_empty()) {
                priv->no_valid_reads = true;
                set_assert();
        }