action: utilize release sequence(s) for synchronization

Instead of checking only the trivial release sequence (i.e., a read-acquire
reads directly from a write-release) for establishing synchronization, make use
of the ModelChecker's more complete 'get_release_seq_head()' functionality,
then loop through all release heads and synchronize with each. This is
necessary because a read-acquire may synchronize with more than one
store-release.

Note that this step only implements support based on present knowledge. The
incomplete knowledge of the modification order, as given in mo_graph, as well
as "reading from the future" may require lazy checking.

diff --git a/action.cc b/action.cc
index 5124780cec727982621a8c7e698f753bf7371e31..b435524d6d4a423405e221724794e8fcfeae4f84 100644 (file)
--- a/action.cc
+++ b/action.cc
@@ -1,6 +1,7 @@
 #include <stdio.h>
 #define __STDC_FORMAT_MACROS
 #include <inttypes.h>
+#include <vector>
 
 #include "model.h"
 #include "action.h"
@@ -166,8 +167,11 @@ void ModelAction::read_from(const ModelAction *act)
 {
        ASSERT(cv);
        reads_from = act;
-       if (act!=NULL && act->is_release() && this->is_acquire()) {
-               synchronize_with(act);
+       if (act != NULL && this->is_acquire()) {
+               std::vector<const ModelAction *> release_heads;
+               model->get_release_seq_heads(this, &release_heads);
+               for (unsigned int i = 0; i < release_heads.size(); i++)
+                       synchronize_with(release_heads[i]);
        }
 }