From: Ivan Maidanski <ivmai@mail.ru>
Date: Thu, 28 Jul 2016 09:06:42 +0000 (+0300)
Subject: Fix tag collision between ENABLE_DISCLAIM and KEEP_BACK_PTRS
X-Git-Tag: v7.4.6~261
X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=9ea81358992c920be52ba80823f5fe3cda817dec;p=gc

Fix tag collision between ENABLE_DISCLAIM and KEEP_BACK_PTRS
(Apply commit 012da3f from 'master' branch.)

* fnlz_mlc.c (FINALIZER_CLOSURE_FLAG): New macro (defined to 0x2 in
case of KEEP_BACK_PTRS or MAKE_BACK_GRAPH, otherwise to 0x1).
* fnlz_mlc.c (GC_finalized_disclaim, GC_finalized_malloc): Use
FINALIZER_CLOSURE_FLAG instead of 0x1.
---

diff --git a/fnlz_mlc.c b/fnlz_mlc.c
index 1305d944..7f8ca84f 100644
--- a/fnlz_mlc.c
+++ b/fnlz_mlc.c
@@ -26,11 +26,18 @@
 
 STATIC int GC_finalized_kind = 0;
 
+#if defined(KEEP_BACK_PTRS) || defined(MAKE_BACK_GRAPH)
+  /* The first bit is already used for a debug purpose. */
+# define FINALIZER_CLOSURE_FLAG 0x2
+#else
+# define FINALIZER_CLOSURE_FLAG 0x1
+#endif
+
 STATIC int GC_CALLBACK GC_finalized_disclaim(void *obj)
 {
     word fc_word = *(word *)obj;
 
-    if ((fc_word & 1) != 0) {
+    if ((fc_word & FINALIZER_CLOSURE_FLAG) != 0) {
        /* The disclaim function may be passed fragments from the        */
        /* free-list, on which it should not run finalization.           */
        /* To recognize this case, we use the fact that the first word   */
@@ -39,7 +46,8 @@ STATIC int GC_CALLBACK GC_finalized_disclaim(void *obj)
        /* which does not use the first word for storing finalization    */
        /* info, GC_reclaim_with_finalization must be extended to clear  */
        /* fragments so that the assumption holds for the selected word. */
-        const struct GC_finalizer_closure *fc = (void *)(fc_word & ~(word)1);
+        const struct GC_finalizer_closure *fc
+                        = (void *)(fc_word & ~(word)FINALIZER_CLOSURE_FLAG);
         (*fc->proc)((word *)obj + 1, fc->cd);
     }
     return 0;
@@ -122,7 +130,7 @@ GC_API void GC_CALL GC_register_disclaim_proc(int kind, GC_disclaim_proc proc,
             return NULL;
         GC_ASSERT(GC_size(op) >= lb);
     }
-    *(word *)op = (word)fclos | 1;
+    *(word *)op = (word)fclos | FINALIZER_CLOSURE_FLAG;
     return GC_clear_stack((word *)op + 1);
 }
 
@@ -163,7 +171,7 @@ GC_API void GC_CALL GC_register_disclaim_proc(int kind, GC_disclaim_proc proc,
     result = (void *)my_entry;
     *my_fl = next;
     obj_link(result) = 0;
-    *(word *)result = (word)fclos | 1;
+    *(word *)result = (word)fclos | FINALIZER_CLOSURE_FLAG;
     GC_PREFETCH_FOR_WRITE(next);
     return (word *)result + 1;
   }