model: refactor add_future_value, add documentation

diff --git a/model.cc b/model.cc
index 7ce959e90b9c5aeaf649df1f422868a63aa34421..32be0538a9077d17951911cb01be66accacbb266 100644 (file)
--- a/model.cc
+++ b/model.cc
@@ -1051,25 +1051,35 @@ bool ModelChecker::process_mutex(ModelAction *curr)
        return false;
 }
 
+/**
+ * @brief Add a future value to a reader
+ *
+ * This function performs a few additional checks to ensure that the future
+ * value can be feasibly observed by the reader
+ *
+ * @param writer The operation whose value is sent. Must be a write.
+ * @param reader The read operation which may read the future value. Must be a read.
+ */
 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)) {
-               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_write_value(),
-                       writer->get_seq_number() + params.maxfuturedelay,
-                       write_thread->get_id(),
-               };
-               if (node->add_future_value(fv))
-                       set_latest_backtrack(reader);
-       }
+       if (!mo_may_allow(writer, reader))
+               return;
+
+       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_write_value(),
+               writer->get_seq_number() + params.maxfuturedelay,
+               write_thread->get_id(),
+       };
+       if (node->add_future_value(fv))
+               set_latest_backtrack(reader);
 }
 
 /**