Yet another good bug (I'm on a roll today! :-)
When squeezing update frames, make sure the updatee pointers aren't
identical before updating one to point to the other. This is mostly
harmless, but in one example I have caused the program to go into an
infinite loop rather than fall down a black hole.
To be merged into the 4.08 branch.
/* -----------------------------------------------------------------------------
/* -----------------------------------------------------------------------------
- * $Id: GC.c,v 1.96 2001/02/11 17:51:07 simonmar Exp $
+ * $Id: GC.c,v 1.97 2001/03/02 14:28:44 simonmar Exp $
*
* (c) The GHC Team 1998-1999
*
*
* (c) The GHC Team 1998-1999
*
* sorted out? oh yes: we aren't counting each enter properly
* in this case. See the log somewhere. KSW 1999-04-21
*/
* sorted out? oh yes: we aren't counting each enter properly
* in this case. See the log somewhere. KSW 1999-04-21
*/
- UPD_IND_NOLOCK(updatee_bypass, updatee_keep); /* this wakes the threads up */
+ if (updatee_bypass != updatee_keep) {
+ /* this wakes the threads up */
+ UPD_IND_NOLOCK(updatee_bypass, updatee_keep);
+ }
sp = (P_)frame - 1; /* sp = stuff to slide */
displacement += sizeofW(StgUpdateFrame);
sp = (P_)frame - 1; /* sp = stuff to slide */
displacement += sizeofW(StgUpdateFrame);