X-Git-Url: http://git.megacz.com/?a=blobdiff_plain;f=ghc%2Frts%2FStable.c;h=5b2635b4ab8053057b5da3e04e0cd8c08177de73;hb=26e23c6a3cba33b4e8846bf92e406974ab87a81a;hp=2d280a4c619d62a57d66bbc8d6a3dbc5f89d17f2;hpb=37cb07db3d7827c8b5058411b12e23e86e6a6520;p=ghc-hetmet.git

diff --git a/ghc/rts/Stable.c b/ghc/rts/Stable.c
index 2d280a4..5b2635b 100644
--- a/ghc/rts/Stable.c
+++ b/ghc/rts/Stable.c
@@ -1,5 +1,5 @@
 /* -----------------------------------------------------------------------------
- * $Id: Stable.c,v 1.9 1999/10/26 17:15:39 sewardj Exp $
+ * $Id: Stable.c,v 1.13 2000/09/04 15:17:03 simonmar Exp $
  *
  * (c) The GHC Team, 1998-1999
  *
@@ -107,7 +107,7 @@ unsigned int SPT_size;
  *
  * A stable pointer has a weighted reference count N attached to it
  * (actually in its upper 5 bits), which represents the weight
- * 2^N.  The stable name entry keeps a 32-bit reference count, which
+ * 2^(N-1).  The stable name entry keeps a 32-bit reference count, which
  * represents any weight between 1 and 2^32 (represented as zero).
  * When the weight is 2^32, the stable name table owns "all" of the
  * stable pointers to this object, and the entry can be garbage
@@ -152,6 +152,27 @@ initStablePtrTable(void)
   SPT_size = 0;
 }
 
+/*
+ * get at the real stuff...remove indirections.
+ *
+ * ToDo: move to a better home.
+ */
+static
+StgClosure*
+removeIndirections(StgClosure* p)
+{
+  StgClosure* q = p;
+
+  while (get_itbl(q)->type == IND ||
+         get_itbl(q)->type == IND_STATIC ||
+         get_itbl(q)->type == IND_OLDGEN ||
+         get_itbl(q)->type == IND_PERM ||
+         get_itbl(q)->type == IND_OLDGEN_PERM ) {
+      q = ((StgInd *)q)->indirectee;
+  }
+  return q;
+}
+
 StgWord
 lookupStableName(StgPtr p)
 {
@@ -160,7 +181,13 @@ lookupStableName(StgPtr p)
   if (stable_ptr_free == NULL) {
     enlargeStablePtrTable();
   }
-    
+
+  /* removing indirections increases the likelihood
+   * of finding a match in the stable name
+   * hash table.
+   */
+  p = (StgPtr)removeIndirections((StgClosure*)p);
+
   (void *)sn = lookupHashTable(addrToStableHash,(W_)p);
   
   if (sn != 0) {
@@ -198,12 +225,12 @@ StgStablePtr
 getStablePtr(StgPtr p)
 {
   StgWord sn = lookupStableName(p);
-  StgWord weight, weight_2;
+  StgWord weight, n;
   weight = stable_ptr_table[sn].weight;
   if (weight == 0) {
     weight = (StgWord)1 << (BITS_IN(StgWord)-1);
     stable_ptr_table[sn].weight = weight;
-    return (StgStablePtr)(sn + ((BITS_IN(StgWord)-1) << STABLEPTR_WEIGHT_SHIFT));
+    return (StgStablePtr)(sn + (BITS_IN(StgWord) << STABLEPTR_WEIGHT_SHIFT));
   } 
   else if (weight == 1) {
     barf("getStablePtr: too light");
@@ -211,11 +238,11 @@ getStablePtr(StgPtr p)
   else {
     weight /= 2;
     /* find log2(weight) */
-    for (weight_2 = 1; weight != 1; weight_2++) {
+    for (n = 0; weight != 1; n++) {
       weight >>= 1;
     }
-    stable_ptr_table[sn].weight -= 2^weight_2;
-    return (StgStablePtr)(sn + (weight_2 << STABLEPTR_WEIGHT_SHIFT));
+    stable_ptr_table[sn].weight -= 1 << n;
+    return (StgStablePtr)(sn + ((n+1) << STABLEPTR_WEIGHT_SHIFT));
   }
 }
 
@@ -295,7 +322,7 @@ markStablePtrTable(rtsBool full)
 	  }
 	  (StgClosure *)p->addr = new;
 	}
-	IF_DEBUG(stable, fprintf(stderr,"Stable ptr %d still alive at %p, weight %d\n", p - stable_ptr_table, new, p->weight));
+	IF_DEBUG(stable, fprintf(stderr,"Stable ptr %d still alive at %p, weight %u\n", p - stable_ptr_table, new, p->weight));
       }
     }
   }