execution: refactor common CV propagation into its own function

There are a few occasions where we want to "fixup" a series of clock
vectors after establishing lazy synchronization (and one place where we
currently have a bug). Refactor this out to its own function so I can
reuse it elsewhere.

diff --git a/execution.cc b/execution.cc
index f2c50c4321c67cd83da4c905ac1bcd652307b4a0..4e154275eac6b42cb4ea805ab9e86bf6a63cd2b5 100644 (file)
--- a/execution.cc
+++ b/execution.cc
@@ -1025,21 +1025,9 @@ void ModelExecution::process_relseq_fixup(ModelAction *curr, work_queue_t *work_
                /* Must synchronize */
                if (!synchronize(release, acquire))
                        return;
-               /* Re-check all pending release sequences */
-               work_queue->push_back(CheckRelSeqWorkEntry(NULL));
-               /* Re-check act for mo_graph edges */
-               work_queue->push_back(MOEdgeWorkEntry(acquire));
-
-               /* propagate synchronization to later actions */
-               action_list_t::reverse_iterator rit = action_trace.rbegin();
-               for (; (*rit) != acquire; rit++) {
-                       ModelAction *propagate = *rit;
-                       if (acquire->happens_before(propagate)) {
-                               synchronize(acquire, propagate);
-                               /* Re-check 'propagate' for mo_graph edges */
-                               work_queue->push_back(MOEdgeWorkEntry(propagate));
-                       }
-               }
+
+               /* Propagate the changed clock vector */
+               propagate_clockvector(acquire, work_queue);
        } else {
                /* Break release sequence with new edges:
                 *   release --mo--> write --mo--> rf */
@@ -2062,6 +2050,37 @@ void ModelExecution::get_release_seq_heads(ModelAction *acquire,
        }
 }
 
+/**
+ * @brief Propagate a modified clock vector to actions later in the execution
+ * order
+ *
+ * After an acquire operation lazily completes a release-sequence
+ * synchronization, we must update all clock vectors for operations later than
+ * the acquire in the execution order.
+ *
+ * @param acquire The ModelAction whose clock vector must be propagated
+ * @param work The work queue to which we can add work items, if this
+ * propagation triggers more updates (e.g., to the modification order)
+ */
+void ModelExecution::propagate_clockvector(ModelAction *acquire, work_queue_t *work)
+{
+       /* Re-check all pending release sequences */
+       work->push_back(CheckRelSeqWorkEntry(NULL));
+       /* Re-check read-acquire for mo_graph edges */
+       work->push_back(MOEdgeWorkEntry(acquire));
+
+       /* propagate synchronization to later actions */
+       action_list_t::reverse_iterator rit = action_trace.rbegin();
+       for (; (*rit) != acquire; rit++) {
+               ModelAction *propagate = *rit;
+               if (acquire->happens_before(propagate)) {
+                       synchronize(acquire, propagate);
+                       /* Re-check 'propagate' for mo_graph edges */
+                       work->push_back(MOEdgeWorkEntry(propagate));
+               }
+       }
+}
+
 /**
  * Attempt to resolve all stashed operations that might synchronize with a
  * release sequence for a given location. This implements the "lazy" portion of
@@ -2100,22 +2119,8 @@ bool ModelExecution::resolve_release_sequences(void *location, work_queue_t *wor
                                        updated = true;
 
                if (updated) {
-                       /* Re-check all pending release sequences */
-                       work_queue->push_back(CheckRelSeqWorkEntry(NULL));
-                       /* Re-check read-acquire for mo_graph edges */
-                       if (acquire->is_read())
-                               work_queue->push_back(MOEdgeWorkEntry(acquire));
-
-                       /* propagate synchronization to later actions */
-                       action_list_t::reverse_iterator rit = action_trace.rbegin();
-                       for (; (*rit) != acquire; rit++) {
-                               ModelAction *propagate = *rit;
-                               if (acquire->happens_before(propagate)) {
-                                       synchronize(acquire, propagate);
-                                       /* Re-check 'propagate' for mo_graph edges */
-                                       work_queue->push_back(MOEdgeWorkEntry(propagate));
-                               }
-                       }
+                       /* Propagate the changed clock vector */
+                       propagate_clockvector(acquire, work_queue);
                }
                if (complete) {
                        it = pending_rel_seqs.erase(it);

diff --git a/execution.h b/execution.h
index 7f63e6d99812c98f5732d35c52a1e04f8691ac17..bb4ebb08f0b67cb3b30af855196c3b2b217b8013 100644 (file)
--- a/execution.h
+++ b/execution.h
@@ -183,6 +183,7 @@ private:
        bool w_modification_order(ModelAction *curr, ModelVector<ModelAction *> *send_fv);
        void get_release_seq_heads(ModelAction *acquire, ModelAction *read, rel_heads_list_t *release_heads);
        bool release_seq_heads(const ModelAction *rf, rel_heads_list_t *release_heads, struct release_seq *pending) const;
+       void propagate_clockvector(ModelAction *acquire, work_queue_t *work);
        bool resolve_release_sequences(void *location, work_queue_t *work_queue);
        void add_future_value(const ModelAction *writer, ModelAction *reader);