Avoid undefined behaviour in ring_elt by using parent (and thus offsetof) instead of deferencing a null pointer. add missing typedef for rememberedsummaryblockstruct. update ring design accordingly.

Copied from Perforce
 Change: 182084
 ServerID: perforce.ravenbrook.com

2 files changed, 7 insertions, 7 deletions

diff --git a/mps/code/ring.h b/mps/code/ring.h
index c7d14ee43d8..d5b64076f6c 100644
--- a/mps/code/ring.h
+++ b/mps/code/ring.h
@@ -1,7 +1,7 @@
 /* ring.h: RING INTERFACE
  *
  * $Id$
- * Copyright (c) 2001,2003 Ravenbrook Limited.  See end of file for license.
+ * Copyright (c) 2001-2013 Ravenbrook Limited.  See end of file for license.
  * Portions copyright (C) 2001 Global Graphics Software.
  */
 
@@ -101,7 +101,7 @@ extern Ring (RingPrev)(Ring ring);
 
 /* .ring.elt: See <design/ring/#elt> */
 #define RING_ELT(type, field, node) \
-   ((type)(void *)((char *)(node) - (size_t)(&((type)0)->field)))
+  PARENT(type ## Struct, field, node)
 
 /* .ring.for: See <design/ring/#for> */
 #define RING_FOR(node, ring, next) \
@@ -115,7 +115,7 @@ extern Ring (RingPrev)(Ring ring);
 
 /* C. COPYRIGHT AND LICENSE
  *
- * Copyright (C) 2001-2003 Ravenbrook Limited <http://www.ravenbrook.com/>.
+ * Copyright (C) 2001-2013 Ravenbrook Limited <http://www.ravenbrook.com/>.
  * All rights reserved.  This is an open source license.  Contact
  * Ravenbrook for commercial licensing options.
  * 
diff --git a/mps/code/traceanc.c b/mps/code/traceanc.c
index e4248580a19..1efb876e2cc 100644
--- a/mps/code/traceanc.c
+++ b/mps/code/traceanc.c
@@ -1,7 +1,7 @@
 /* traceanc.c: ANCILLARY SUPPORT FOR TRACER
  *
  * $Id$
- * Copyright (c) 2001-2003, 2006-2008 Ravenbrook Limited.
+ * Copyright (c) 2001-2013 Ravenbrook Limited.
  * See end of file for license.
  * Portions copyright (C) 2002 Global Graphics Software.
  *
@@ -637,13 +637,13 @@ Res ArenaCollect(Globals globals, int why)
 
 /* Low level stuff for Expose / Remember / Restore */
 
-struct RememberedSummaryBlockStruct {
+typedef struct RememberedSummaryBlockStruct {
   RingStruct globalRing;        /* link on globals->rememberedSummaryRing */
   struct SummaryPair {
     Addr base;
     RefSet summary;
   } the[RememberedSummaryBLOCK];
-};
+} RememberedSummaryBlockStruct;
 
 typedef struct RememberedSummaryBlockStruct *RememberedSummaryBlock;
 
@@ -793,7 +793,7 @@ static void arenaForgetProtection(Globals globals)
 
 /* C. COPYRIGHT AND LICENSE
  *
- * Copyright (C) 2001-2003, 2006-2008 Ravenbrook Limited
+ * Copyright (C) 2001-2013 Ravenbrook Limited
  * <http://www.ravenbrook.com/>.
  * All rights reserved.  This is an open source license.  Contact
  * Ravenbrook for commercial licensing options.