Remove origin arguments from write barrier functionswip/nonmoving-gc

Write barriers push old values of updated field, e.g. when we have

    *q = p;

we do

    updateRemembSetPushClosure(*q, q);
    *q = p;

Here the second argument ("origin") is not useful because by the time we
do the update we invalidate "origin" (`q` is no longer origin of old
`*q`).

In general it doesn't make sense to record origins in write barriers so
we remove all origin arguments from write barriers.

Fixes #170.

1 files changed, 8 insertions, 10 deletions

diff --git a/rts/sm/Storage.c b/rts/sm/Storage.c
index dd253ade57..6fa6d777a8 100644
--- a/rts/sm/Storage.c
+++ b/rts/sm/Storage.c
@@ -433,7 +433,7 @@ lockCAF (StgRegTable *reg, StgIndStatic *caf)
     if (nonmoving_write_barrier_enabled) {
         StgThunkInfoTable *thunk_info = itbl_to_thunk_itbl(orig_info_tbl);
         if (thunk_info->i.srt) {
-            updateRemembSetPushClosure(cap, GET_SRT(thunk_info), NULL);
+            updateRemembSetPushClosure(cap, GET_SRT(thunk_info));
         }
     }
 
@@ -1141,9 +1141,7 @@ dirty_MUT_VAR(StgRegTable *reg, StgMutVar *mvar, StgClosure *old)
         mvar->header.info = &stg_MUT_VAR_DIRTY_info;
         recordClosureMutated(cap, (StgClosure *) mvar);
         if (nonmoving_write_barrier_enabled != 0) {
-            updateRemembSetPushClosure_(reg,
-                                      old,
-                                      &mvar->var);
+            updateRemembSetPushClosure_(reg, old);
         }
     }
 }
@@ -1162,7 +1160,7 @@ dirty_TVAR(Capability *cap, StgTVar *p,
         p->header.info = &stg_TVAR_DIRTY_info;
         recordClosureMutated(cap,(StgClosure*)p);
         if (nonmoving_write_barrier_enabled != 0) {
-            updateRemembSetPushClosure(cap, old, NULL);
+            updateRemembSetPushClosure(cap, old);
         }
     }
 }
@@ -1179,7 +1177,7 @@ setTSOLink (Capability *cap, StgTSO *tso, StgTSO *target)
         tso->dirty = 1;
         recordClosureMutated(cap,(StgClosure*)tso);
         if (nonmoving_write_barrier_enabled)
-            updateRemembSetPushClosure(cap, (StgClosure *) tso->_link, NULL);
+            updateRemembSetPushClosure(cap, (StgClosure *) tso->_link);
     }
     tso->_link = target;
 }
@@ -1191,7 +1189,7 @@ setTSOPrev (Capability *cap, StgTSO *tso, StgTSO *target)
         tso->dirty = 1;
         recordClosureMutated(cap,(StgClosure*)tso);
         if (nonmoving_write_barrier_enabled)
-            updateRemembSetPushClosure(cap, (StgClosure *) tso->block_info.prev, NULL);
+            updateRemembSetPushClosure(cap, (StgClosure *) tso->block_info.prev);
     }
     tso->block_info.prev = target;
 }
@@ -1240,9 +1238,9 @@ update_MVAR(StgRegTable *reg, StgClosure *p, StgClosure *old_val)
     Capability *cap = regTableToCapability(reg);
     if (nonmoving_write_barrier_enabled) {
         StgMVar *mvar = (StgMVar *) p;
-        updateRemembSetPushClosure(cap, old_val, NULL);
-        updateRemembSetPushClosure(cap, (StgClosure *) mvar->head, NULL);
-        updateRemembSetPushClosure(cap, (StgClosure *) mvar->tail, NULL);
+        updateRemembSetPushClosure(cap, old_val);
+        updateRemembSetPushClosure(cap, (StgClosure *) mvar->head);
+        updateRemembSetPushClosure(cap, (StgClosure *) mvar->tail);
     }
 }