gc6.3alpha5 tarball importgc6_3alpha5

1 files changed, 29 insertions, 0 deletions

diff --git a/finalize.c b/finalize.c
index 3b9d9f5e..e103228c 100644
--- a/finalize.c
+++ b/finalize.c
@@ -807,8 +807,37 @@ void (* GC_finalizer_notifier)() = (void (*) GC_PROTO((void)))0;
 
 static GC_word last_finalizer_notification = 0;
 
+#ifdef KEEP_BACK_PTRS
+void GC_generate_random_backtrace_no_gc(void);
+#endif
+
 void GC_notify_or_invoke_finalizers GC_PROTO((void))
 {
+    /* This is a convenient place to generate backtraces if appropriate, */
+    /* since that code is not callable with the allocation lock.	 */
+#   ifdef KEEP_BACK_PTRS
+      if (GC_backtraces > 0) {
+	static word last_back_trace_gc_no = 3;	/* Skip early ones. */
+	long i;
+
+	LOCK();
+	if (GC_gc_no > last_back_trace_gc_no) {
+	  /* Stops when GC_gc_no wraps; that's OK.	*/
+	    last_back_trace_gc_no = (word)(-1);  /* disable others. */
+	    for (i = 0; i < GC_backtraces; ++i) {
+	      /* FIXME: This tolerates concurrent heap mutation,	*/
+	      /* which may cause occasional mysterious results.		*/
+	      /* We need to release the GC lock, since GC_print_callers	*/
+	      /* acquires it.  It probably shouldn't.			*/
+	      UNLOCK();
+	      GC_generate_random_backtrace_no_gc();
+	      LOCK();
+	    }
+	    last_back_trace_gc_no = GC_gc_no;
+	}
+	UNLOCK();
+      }
+#   endif
     if (GC_finalize_now == 0) return;
     if (!GC_finalize_on_demand) {
 	(void) GC_invoke_finalizers();