X-Git-Url: http://git.megacz.com/?a=blobdiff_plain;f=rts%2Fsm%2FMarkWeak.c;h=72f0ade797ef087956f218dd2d105ed066411358;hb=26f4bfc82f2b2359259578e9c54d476fc2de650f;hp=9df39b9a08edd5be7f6bca658df78ca807392a2d;hpb=7408b39235bccdcde48df2a73337ff976fbc09b7;p=ghc-hetmet.git

diff --git a/rts/sm/MarkWeak.c b/rts/sm/MarkWeak.c
index 9df39b9..72f0ade 100644
--- a/rts/sm/MarkWeak.c
+++ b/rts/sm/MarkWeak.c
@@ -210,21 +210,6 @@ traverseWeakPtrList(void)
           }
       }
         
-      /* Finally, we can update the blackhole_queue.  This queue
-       * simply strings together TSOs blocked on black holes, it is
-       * not intended to keep anything alive.  Hence, we do not follow
-       * pointers on the blackhole_queue until now, when we have
-       * determined which TSOs are otherwise reachable.  We know at
-       * this point that all TSOs have been evacuated, however.
-       */
-      { 
-	  StgTSO **pt;
-	  for (pt = &blackhole_queue; *pt != END_TSO_QUEUE; pt = &((*pt)->_link)) {
-	      *pt = (StgTSO *)isAlive((StgClosure *)*pt);
-	      ASSERT(*pt != NULL);
-	  }
-      }
-      
       weak_stage = WeakDone;  // *now* we're done,
       return rtsTrue;         // but one more round of scavenging, please
   }
@@ -275,18 +260,15 @@ static rtsBool tidyThreadList (generation *gen)
         }
         
         ASSERT(get_itbl(t)->type == TSO);
-        if (t->what_next == ThreadRelocated) {
-            next = t->_link;
-            *prev = next;
-            continue;
-        }
-        
         next = t->global_link;
         
         // if the thread is not masking exceptions but there are
         // pending exceptions on its queue, then something has gone
-        // wrong:
+        // wrong.  However, pending exceptions are OK if there is an
+        // FFI call.
         ASSERT(t->blocked_exceptions == END_BLOCKED_EXCEPTIONS_QUEUE
+               || t->why_blocked == BlockedOnCCall
+               || t->why_blocked == BlockedOnCCall_Interruptible
                || (t->flags & TSO_BLOCKEX));
         
         if (tmp == NULL) {
@@ -310,49 +292,6 @@ static rtsBool tidyThreadList (generation *gen)
 }
 
 /* -----------------------------------------------------------------------------
-   The blackhole queue
-   
-   Threads on this list behave like weak pointers during the normal
-   phase of garbage collection: if the blackhole is reachable, then
-   the thread is reachable too.
-   -------------------------------------------------------------------------- */
-rtsBool
-traverseBlackholeQueue (void)
-{
-    StgTSO *prev, *t, *tmp;
-    rtsBool flag;
-    nat type;
-
-    flag = rtsFalse;
-    prev = NULL;
-
-    for (t = blackhole_queue; t != END_TSO_QUEUE; prev=t, t = t->_link) {
-        // if the thread is not yet alive...
-	if (! (tmp = (StgTSO *)isAlive((StgClosure*)t))) {
-            // if the closure it is blocked on is either (a) a
-            // reachable BLAKCHOLE or (b) not a BLACKHOLE, then we
-            // make the thread alive.
-	    if (!isAlive(t->block_info.closure)) {
-                type = get_itbl(t->block_info.closure)->type;
-                if (type == BLACKHOLE || type == CAF_BLACKHOLE) {
-                    continue;
-                }
-            }
-            evacuate((StgClosure **)&t);
-            if (prev) {
-                prev->_link = t;
-            } else {
-                blackhole_queue = t;
-            }
-                 // no write barrier when on the blackhole queue,
-                 // because we traverse the whole queue on every GC.
-            flag = rtsTrue;
-	}
-    }
-    return flag;
-}
-
-/* -----------------------------------------------------------------------------
    Evacuate every weak pointer object on the weak_ptr_list, and update
    the link fields.
 
@@ -368,9 +307,18 @@ markWeakPtrList ( void )
   last_w = &weak_ptr_list;
   for (w = weak_ptr_list; w; w = w->link) {
       // w might be WEAK, EVACUATED, or DEAD_WEAK (actually CON_STATIC) here
-      ASSERT(IS_FORWARDING_PTR(w->header.info)
-             || w->header.info == &stg_DEAD_WEAK_info 
-	     || get_itbl(w)->type == WEAK);
+
+#ifdef DEBUG
+      {   // careful to do this assertion only reading the info ptr
+          // once, because during parallel GC it might change under our feet.
+          const StgInfoTable *info;
+          info = w->header.info;
+          ASSERT(IS_FORWARDING_PTR(info)
+                 || info == &stg_DEAD_WEAK_info 
+                 || INFO_PTR_TO_STRUCT(info)->type == WEAK);
+      }
+#endif
+
       evacuate((StgClosure **)last_w);
       w = *last_w;
       if (w->header.info == &stg_DEAD_WEAK_info) {